Small molecule coated silicon nitride monodisperse antibacterial colloid and preparation method and application thereof

Abstract

The present invention relates to the technical field of nanomaterials. The present invention provides a small molecule-coated silicon nitride monodisperse antibacterial colloid and a preparation method and application thereof. The antibacterial colloid has monodisperse particles of small molecule-coated silicon nitride, and the small molecule-coated silicon nitride monodisperse antibacterial colloid is formed by silicon nitride, a small molecule dispersant and water through high-energy ball milling; the small molecule dispersant is selected from hexametaphosphate. The dispersion performance of this material in water is improved by the method of the embodiment of the present invention, so that the size of the material can be stable for a long time. The small molecule described in the present invention is coated with silicon nitride by a mechanical-chemical modification method to avoid agglomeration of silicon nitride after ball milling dispersion. At the same time, the colloid has good antibacterial properties against both Gram-positive bacteria and Gram-negative bacteria, which is conducive to application.

Description

Technical Field

[0001] The invention relates to the technical field of nanomaterials, and in particular to a small molecule-coated silicon nitride monodisperse antibacterial colloid and a preparation method and application thereof. Background Art

[0002] Nanomaterials (generally ranging in size from 1 to 100 nm) have small size effects and surface effects, so they have large specific surface areas and surface energy, and are prone to agglomeration. Among them, silicon nitride is a new type of inorganic material with special properties in catalysis, optics, magnetism, etc., and is widely used in chemical fields such as ceramics, rubber, and coatings. However, as a nano-scale material, silicon nitride also has the disadvantages of being easy to agglomerate and having poor dispersibility in water, which limits the full application effect of this material. Therefore, it is necessary to use certain dispersants and dispersion methods to eliminate agglomeration and improve dispersion stability, so that silicon nitride can play its maximum effect.

[0003] The commonly used method of dispersing nanomaterials includes two parts: first, mechanically dispersing the nanoparticles, and then coating the silicon nitride particles with a dispersant, which can effectively prevent the occurrence of agglomeration and achieve a uniform effect. Mechanical ball milling can break up the agglomerates of silicon nitride, and the dispersant interacts with the dangling bonds on the surface of silicon nitride to form a protective film with a coating effect on the surface to prevent the particles from agglomerating again.

[0004] Silicon nitride can release free electrons and generate active oxygen with oxygen, killing most bacteria through oxidation reactions. It is often used as an antibacterial agent in daily plastics, architectural coatings, food packaging, ceramics and other fields. The shape and size of silicon nitride have a great influence on its bactericidal ability, and the antibacterial effect of existing silicon nitride nanomaterials needs to be further improved. Summary of the invention

[0005] Based on this, the present invention provides a small molecule coated silicon nitride monodisperse antibacterial colloid and its preparation method and application. The silicon nitride antibacterial colloid obtained by the method of the present invention is dispersed stably and has improved antibacterial effect, which is conducive to application in antibacterial products.

[0006] The present invention provides a small molecule-coated silicon nitride monodisperse antibacterial colloid, which has small molecule-coated silicon nitride monodisperse particles, and the small molecule-coated silicon nitride monodisperse antibacterial colloid is formed by silicon nitride, a small molecule dispersant and water through high-energy ball milling;

[0007] The small molecule dispersant is selected from hexametaphosphate.

[0008] In one embodiment, the mass ratio of silicon nitride to water is 1:100-1:10000; and / or the mass ratio of silicon nitride to small molecule dispersant is 1:1-10:1.

[0009] In one embodiment, the small molecule dispersant further comprises a small molecule auxiliary agent, and the small molecule auxiliary agent is selected from one or more of dodecylbenzene sulfonate, polyethylene glycol and tripolyphosphate.

[0010] In one of the embodiments, the small molecule-coated silicon nitride monodisperse antibacterial colloid has an antibacterial effect on both Staphylococcus aureus and Escherichia coli.

[0011] The present invention provides a method for preparing the small molecule-coated silicon nitride monodisperse antibacterial colloid as described above, comprising the following steps:

[0012] Silicon nitride, a small molecule dispersant, water and a ball milling medium are mixed, high-energy ball milling is performed, and then the ball milling medium is removed to obtain a small molecule-coated silicon nitride monodisperse antibacterial colloid.

[0013] In one embodiment, the high energy ball milling time is 2h-10h, and / or the rotation speed is 200r / min-800r / min.

[0014] In one embodiment, the temperature of the high energy ball milling is 20°C-50°C.

[0015] In one embodiment, the ball milling medium is zirconia beads, and the particle size is 0.1 mm-0.5 mm.

[0016] In one embodiment, the small molecule dispersant is sodium hexametaphosphate, or one or a combination of sodium hexametaphosphate, sodium dodecylbenzene sulfonate, polyethylene glycol and sodium tripolyphosphate.

[0017] In one embodiment, the purity of the small molecule dispersant is AR grade.

[0018] The present invention provides use of any of the above-mentioned small molecule-coated silicon nitride monodisperse antibacterial colloids in the preparation of antibacterial materials.

[0019] The invention provides an antibacterial material, comprising a main raw material and any one of the above-mentioned small molecule-coated silicon nitride monodisperse antibacterial colloids.

[0020] The invention provides a mildew-proof and antibacterial plastic, and the preparation raw materials include: common plastic polyethylene and the small molecule-coated silicon nitride monodisperse antibacterial colloid described in any one of the above items.

[0021] In one of the embodiments, the addition amount of the small molecule-encapsulated silicon nitride monodisperse antibacterial colloid is 0.1-2% of the mass of the mildew-proof and antibacterial plastic.

[0022] The present invention provides a method for preparing the mildew-proof and antibacterial plastic, comprising the following steps:

[0023] S1, centrifuging the small molecule-coated silicon nitride monodisperse antibacterial colloid and sending it into an oven for drying, grinding and crushing it, and then sieving it to obtain silicon nitride antibacterial powder;

[0024] S2, placing the antibacterial powder obtained in step S1 and common plastic polyethylene in a granulator for blending, extrusion and granulation to obtain an antibacterial masterbatch;

[0025] S3, drying the antibacterial masterbatch obtained in step S2, and then mixing it with ordinary plastic polyethylene in an injection molding machine for injection molding, and hot pressing to obtain an antibacterial plastic plate.

[0026] In one embodiment, the twin-screw extrusion temperature of the granulator is 180°C, 200°C, 210°C, the extrusion speed is 18r / min, and the pelletizer speed is 12r / min.

[0027] The present invention provides an antibacterial fiber membrane, the preparation raw materials of which include: cellulose acetate and the small molecule-coated silicon nitride monodisperse antibacterial colloid described in any one of the above items.

[0028] In one of the embodiments, the small molecule-coated silicon nitride monodisperse antibacterial colloid accounts for 0.5-2% of the mass of the antibacterial fiber membrane.

[0029] The present invention provides a method for preparing the antibacterial fiber membrane, comprising the following steps:

[0030] S1. Prepare cellulose acetate spinning solution: dissolve cellulose acetate in solvent, acetone / DMAc / water (7 / 2 / 1 w / w / w);

[0031] S2, mixing the small molecule-coated silicon nitride monodisperse antibacterial colloid with the cellulose acetate spinning solution of step S1 at a ratio of 0.5-2%;

[0032] S3. Spin the mixed spinning solution obtained in the above step S2 according to the process parameters (preferably: spinning voltage 15-25 kV, receiving distance 15-20 cm, injection pump flow rate 1-2 ml / h, spinning temperature 20-30°C, relative humidity 45-55%) to obtain an antibacterial fiber membrane.

[0033] The inventors of this application have discovered, based on their long-term experience in this field and creative experiments, that in addition to introducing small molecule dispersants to modify the surface of silicon nitride, in this process, large particles of silicon nitride are ground and dispersed into small particles through high-energy ball milling, and then the small molecule dispersants are used to coat the silicon nitride particles to reduce the surface energy of silicon nitride, which is more conducive to improving the dispersion performance of silicon nitride in water.

[0034] The particle size of the antibacterial colloidal silicon nitride is optimized by the method of the embodiment of the present invention, the dispersion performance of this material in water is improved, the disadvantage of easy agglomeration of nanomaterials due to high surface energy and large specific surface area is overcome, and the size of the material can be stable for a long time. The small molecules described in the present invention are coated with silicon nitride particles by a mechanical-chemical modification method to reduce the effects of van der Waals forces and electrostatic attraction between particles, thereby avoiding agglomeration of silicon nitride after ball milling dispersion. At the same time, the antibacterial performance of the obtained colloid is studied, and the colloid has good antibacterial performance against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli).

[0035] Furthermore, the small molecule-coated silicon nitride monodisperse antibacterial colloid also has the characteristics of high temperature resistance, good durability, stability and non-toxicity.

[0036] The present invention provides an application of the small molecule-coated silicon nitride monodisperse antibacterial colloid described in any one of the above items in the preparation of an antibacterial material, that is, an antibacterial material is provided, comprising: a main raw material and any one of the small molecule-coated silicon nitride monodisperse antibacterial colloids described in the above items. The main raw material includes but is not limited to: natural or synthetic polymers, ceramics, etc., and the material form is not particularly limited.

[0037] One of the embodiments provides a mildew-proof and antibacterial plastic, which uses the small molecule-coated silicon nitride monodisperse antibacterial colloid as described in any of the above items as an auxiliary preparation raw material; mainly by using the extrusion granulation method, the antibacterial colloid is blended with ordinary plastic polyethylene (PE) for extrusion granulation to obtain an antibacterial masterbatch containing silicon nitride antibacterial components, and then the dried antibacterial masterbatch is blended with ordinary plastic polyethylene, and injection molding and hot pressing are used to obtain an antibacterial and mildew-proof plastic board. In the present invention, the antibacterial powder prepared by the small molecule-coated silicon nitride monodisperse antibacterial colloid has good dispersibility when blended with plastic, and will not affect the original color and gloss of the plastic. Only a small amount needs to be added to achieve a good antibacterial and mildew-proof effect. This preparation process is efficient and easy to operate, and the addition of the antibacterial component will not affect the original performance and gloss of the plastic, which is convenient for industrial production.

[0038] One of the embodiments provides an antibacterial fiber membrane, which uses the small molecule-coated silicon nitride monodisperse antibacterial colloid described in any of the above items as an auxiliary preparation raw material; it can be evenly mixed with cellulose acetate, and then the corresponding spinning process parameters are adjusted by combining electrospinning technology to obtain the antibacterial fiber membrane. In the present invention, the small molecule-coated silicon nitride monodisperse antibacterial colloid is used to prepare a fiber membrane together with cellulose acetate with good biocompatibility, giving the cellulose acetate membrane an antibacterial effect. Compared with the existing traditional cotton gauze dressings, the antibacterial fiber membrane described in the present invention is more suitable for wounds. At the same time, by releasing free electrons and generating active oxygen with oxygen, it has a more stable antibacterial process and a long antibacterial effect. It can not only effectively promote the healing of human wounds, but also is non-toxic to the human body and will not cause secondary damage to the wound when used.

[0039] In addition, it can also be used in ceramic products to meet the requirements of antibacterial durability and other requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Digital photos of the colloids of Example 1 (left) and Comparative Example 1 (right);

[0041] Figure 2 The Tyndall effect of the colloid of Example 1;

[0042] Figure 3 is a TEM image of the colloid of Example 1;

[0043] Figure 4 Digital photos of the plastics of Example 6 (left) and Comparative Example 4 (right);

[0044] Figure 5 Digital photos of the fiber membranes of Example 9 (left) and Comparative Example 5 (right). DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present application are clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0046] The present invention provides a small molecule-coated silicon nitride monodisperse antibacterial colloid, which has small molecule-coated silicon nitride monodisperse particles, and the small molecule-coated silicon nitride monodisperse antibacterial colloid is formed by silicon nitride, a small molecule dispersant and water through high-energy ball milling;

[0047] The small molecule dispersant is selected from hexametaphosphate; or is one or a combination of hexametaphosphate, dodecylbenzene sulfonate, polyethylene glycol and tripolyphosphate;

[0048] The mass ratio of the silicon nitride to the small molecule dispersant is preferably 1:1-10:1.

[0049] In the small molecule-coated silicon nitride monodisperse antibacterial colloid provided by the present invention, the size of silicon nitride can be stable for a long time and is not easy to agglomerate; the colloid has good antibacterial performance.

[0050] Colloid, also known as colloidal dispersion, is a homogeneous mixture and highly dispersed multiphase system. It contains two substances in different states, one dispersed phase (system) and the other continuous phase. Colloids can produce Tyndall phenomenon, etc.

[0051] In the small molecule-coated silicon nitride monodisperse antibacterial colloid of the present invention, the dispersed phase is monodisperse particles of small molecule-coated silicon nitride, and the diameter of the dispersed particles is between 1nm and 100nm; it is an aqueous colloid, and water is the continuous phase.

[0052] The method for preparing the small molecule silicon nitride monodisperse antibacterial colloid of the present invention utilizes a mechanical-chemical modification method to coat some small molecule substances onto the surface of silicon nitride to improve the dispersibility of silicon nitride. The prepared small molecule coated silicon nitride monodisperse antibacterial colloid exhibits good dispersibility in water, thereby achieving the purpose of improving the antibacterial effect.

[0053] The preparation method described in the embodiment of the present invention comprises: mixing silicon nitride, a small molecule dispersant sodium hexametaphosphate, water and a ball milling medium in a certain mass ratio, high-energy ball milling, and then removing the ball milling medium to obtain the small molecule-coated silicon nitride monodisperse antibacterial colloid.

[0054] The present invention mainly introduces a specific small molecule dispersant and adopts a high-energy mechanical ball milling method to grind and disperse large particles of silicon nitride into small particles, and then combines the coating of silicon nitride particles with small molecules to reduce the surface energy of silicon nitride and the van der Waals force and electrostatic attraction between particles, which is more conducive to improving the dispersibility of silicon nitride in water and improving antibacterial properties. By mechanically (ball milling)-chemically modifying silicon nitride with the method of the present invention, the dispersibility of silicon nitride in water can be significantly improved, and the secondary agglomeration phenomenon caused by thermodynamic and kinetic instability of nanomaterials can be overcome, so as to fully demonstrate its excellent performance. The small molecules are wrapped with silicon nitride particles by a mechanical-chemical modification method, which reduces the van der Waals force between particles and avoids the secondary agglomeration of silicon nitride after ball milling dispersion. The obtained colloid also has good dispersibility in water, and the nitride colloidal body prepared by the present invention can be stably stored for a long time. At the same time, by studying the antibacterial properties of the obtained colloid, it is found that the colloid has good antibacterial properties against Staphylococcus aureus and Escherichia coli.

[0055] In the present invention, the small molecule dispersant is selected from hexametaphosphate; preferably, it also contains one or more small molecule additives selected from dodecylbenzene sulfonate, polyethylene glycol (molecular weight 4000-6000) and tripolyphosphate, generally sodium salt; sodium hexametaphosphate can be introduced alone, or multiple small molecule additives can be added together. Preferably, the purity of the small molecule dispersant is AR grade.

[0056] Moreover, the mass ratio of silicon nitride to small molecule dispersant of the present invention is 1:1-10:1. Preferably, the total mass ratio of silicon nitride to small molecule dispersant is (1:1)-(9:1). It can be understood that the mass ratio of silicon nitride to small molecule dispersant includes but is not limited to: 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1. More preferably, the mass ratio of silicon nitride to small molecule dispersant is (2:1)-(8:1).

[0057] Preferably, the particle size of the modified silicon nitride in the embodiment of the present invention is 50nm-100nm; the silicon nitride raw material is commercially available ordinary silicon nitride with a purity of 99.99%, a particle size of about 300-1400nm, and is in the form of agglomerates (commercially available silicon nitride tends to agglomerate to stabilize itself during storage due to thermodynamic and kinetic instability, so it is called "agglomerate").

[0058] Preferably, the mass ratio of silicon nitride to water is (1:100)-(1:10000). More preferably, the mass ratio of silicon nitride to water is (1:250)-(1:10000). It can be understood that the mass ratio of silicon nitride to water includes but is not limited to: 1:250, 1:500, 1:1000, 1:1500, 1:2000, 1:2500, 1:3000, 1:3500, 1:4000, 1:5000, 1:6000, 1:7000, 1:7500, 1:8000, 1:9000, 1:10000. Preferably, the water is deionized water, which can be homemade in the laboratory or commercially available, and has a pH of 6.5-6.8.

[0059] High-energy ball milling is a method of using the rotation or vibration of the ball mill to make the hard balls strongly impact, grind and stir the raw materials to crush the powder into nano-sized particles. It can be understood that ball milling can be carried out in conventional equipment such as planetary ball mills. After the ball milling is completed, the ball mill jar is removed and the ball milling medium is removed.

[0060] Preferably, the rotation speed of the high energy ball mill of the present invention is 200 r / min-800 r / min. More preferably, the rotation speed of the ball mill is 600-700 r / min.

[0061] Preferably, the high-energy ball milling time is 2h-10h. More preferably, the ball milling time is 3h-6h. Through experimental studies, it is found that the length of ball milling time will affect the dispersion form of silicon nitride in water. Controlling the ball milling time can obtain a more uniform and transparent colloid and obtain a better antibacterial effect. After ball milling, the ball milling medium is removed to obtain a small molecule coated silicon nitride antibacterial colloid.

[0062] Optionally, the ball milling medium is zirconium oxide beads with a particle size of 0.1mm-0.5mm. Preferably, the ball milling medium is zirconium oxide beads with a particle size of 0.1mm-0.2mm, for example, 50g of 0.1mm zirconium oxide beads are used as ball milling media. Preferably, the mass ratio of silicon nitride to ball milling medium is (1:100)-(1:10000). Through experimental studies, it was found that the particle size of the ball milling medium will affect the dispersion form of silicon nitride in water. By controlling the particle size of the ball milling medium, a more uniform and transparent colloid can be obtained, thereby obtaining a better antibacterial effect.

[0063] In the embodiment of the present invention, the temperature of the high energy ball milling is 20° C.-50° C. During the experiment, the experiment will not be significantly affected by the seasonal climate change, the conditions are simple and suitable for process amplification, the high energy ball milling is carried out under normal pressure, and during the ball milling, the pH value of the liquid is maintained at 9-9.5.

[0064] The mechanical-chemical modification method used in the technology of the present invention coats the silicon nitride surface with small molecules of the dispersant through mechanical dispersion and high-energy ball milling, thereby preparing a monodisperse antibacterial colloidal solution of silicon nitride that is well dispersed and can be stably preserved. At the same time, the prepared antibacterial colloidal solution is environmentally friendly. Compared with the slow-release antibacterial agent that relies on metal ions, the active oxygen antibacterial of the silicon nitride of the present invention has a longer efficacy time.

[0065] Compared with mixing silicon nitride, a small molecule dispersant, and water and then stirring them, or ultrasonic stirring, the present invention adds a ball milling process to mix the three, effectively coating the small molecule dispersant on silicon nitride, and the prepared nitride colloidal body has better dispersibility and is more uniform. After the prepared nitride colloidal body in the embodiment of the present invention is centrifuged at 8000r / min, the colloid has no precipitation and obvious changes, indicating that the nitride colloidal body can be stably stored for a long time and has better antibacterial properties.

[0066] The above method is simple in process for preparing nitride colloidal body, easy to realize large-scale industrial production, and low in reagent price. The prepared nitride colloidal body has good stability and good dispersibility in water. The prepared colloid has excellent antibacterial properties, further broadens the application field of silicon nitride, makes it more conducive to research, has no impact on the environment, and the produced solution can be recovered.

[0067] The small molecule coated silicon nitride antibacterial colloid provided by the present invention can be prepared by the above method; the prepared small molecule coated silicon nitride antibacterial colloid also has good dispersibility in water, and the preparation operation is simple, the cost is low, and the reproducibility is good. The present invention also performs transmission scanning electron microscopy (TEM) and other aspects of detection and analysis on the prepared small molecule dispersant coated silicon nitride antibacterial colloid.

[0068] The monodisperse colloid obtained above has good water solubility. By conducting antibacterial tests on this well-dispersed colloid, it was found that the silicon nitride aqueous colloid coated with a small molecule dispersant has excellent antibacterial properties; in some embodiments, its minimum inhibitory concentration (MIC) is 39 ppm for Staphylococcus aureus and 78 ppm for Escherichia coli, which is much lower than the antibacterial concentration of commercially available silicon nitride, improving the current shortcoming of silicon nitride directly used in antibacterial materials with weak antibacterial properties.

[0069] Furthermore, the present invention provides the use of any of the above-mentioned small molecule-coated silicon nitride monodisperse antibacterial colloids in the preparation of antibacterial materials.

[0070] Existing antibacterial plastics refer to ordinary plastics that have been treated with antibacterial agents or added with certain conventional antibacterial agents, thus having antibacterial effects. They can be used in home appliances, food packaging, toys, etc. Since the production conditions of plastics involve high temperature and high pressure, and organic antibacterial agents are prone to decomposition at high temperatures and produce toxic substances, they are not suitable for use in the plastic field. Silver ions are commonly used in conventional inorganic antibacterial agents, but this type of antibacterial material has the disadvantage of insufficient antibacterial durability.

[0071] Some embodiments of the present invention provide a mildew-proof and antibacterial plastic, the preparation raw materials of which include: ordinary plastic polyethylene and the small molecule-encapsulated silicon nitride monodisperse antibacterial colloid described in any of the above items; the antibacterial plastic board can be obtained by co-blending extrusion granulation, co-blending injection molding, and hot pressing molding, and has good antibacterial and mildew-proof effects.

[0072] In the technical scheme of the embodiment of the present invention, there is no special restriction on the polyethylene (PE) plastic resin, and conventional ordinary polyethylene is used; and the small molecule coated silicon nitride monodisperse antibacterial colloid described above is used as an antibacterial and mildew-proof additive for antibacterial plastics. The silicon nitride therein activates oxygen in the air to become active oxygen by generating free electrons and holes, has extremely strong oxidizing activity, can penetrate the cell membrane of bacteria, destroy its cell structure, and has a good inhibitory effect on bacteria and mold. In addition, it is resistant to high temperatures, has good durability, is stable and non-toxic, has good dispersibility when blended with plastics, and will not affect the original color and gloss of the plastic. Only a small amount of the antibacterial component needs to be added. Preferably, the addition amount of the small molecule coated silicon nitride monodisperse antibacterial colloid accounts for 0.1-2% of the mass of the mildew-proof and mildew-proof plastic, which can achieve a good antibacterial and mildew-proof effect.

[0073] The embodiment of the present invention provides a method for preparing the mildew-proof and antibacterial plastic, comprising the following steps:

[0074] S1, centrifuging the small molecule-coated silicon nitride monodisperse antibacterial colloid, and then drying it in an oven, grinding and crushing it, and sieving it to obtain silicon nitride antibacterial powder;

[0075] S2, placing the antibacterial powder obtained in step S1 and common plastic polyethylene in a granulator for blending, extrusion and granulation to obtain an antibacterial masterbatch;

[0076] S3, drying the antibacterial masterbatch obtained in the above step S2, placing it in an injection molding machine for mixed injection molding with ordinary plastic polyethylene, and hot pressing to obtain an antibacterial plastic plate.

[0077] In the embodiment of the present invention, the small molecule-coated silicon nitride monodisperse antibacterial colloid is first made into silicon nitride antibacterial powder with a particle size of 50-100nm. After that, it is blended and granulated with ordinary plastic polyethylene to maintain good dispersibility in the plastic. Compared with existing organic antibacterial agents, the silicon nitride in the present invention has a more stable antibacterial process. It releases free electrons, generates active oxygen with oxygen, and kills most bacteria through oxidation reactions. It is non-toxic and has a longer antibacterial effect. And while the amount of antibacterial ingredients added is low, it has excellent antibacterial properties against Staphylococcus aureus and Escherichia coli.

[0078] The above silicon nitride antibacterial powder can be added to common plastic polyethylene, mixed evenly, and then extruded, drawn, and water-cooled by a granulator to obtain antibacterial masterbatch containing silicon nitride. The masterbatch obtained in the granulation process has a particle size of, for example, 30*30*0.5 mm.

[0079] In a preferred embodiment, the twin-screw extrusion temperature of the granulator is 180°C, 200°C, 210°C; the extrusion speed can be 18r / min. The water cooling temperature of the granulator is generally ordinary tap water cooling, and the pelletizer speed can be 12r / min. Specifically, the embodiment of the present invention can use polyethylene with a molecular weight of 5000.

[0080] In the embodiment of the present invention, a portion of the dried silicon nitride antibacterial masterbatch is taken, uniformly mixed with ordinary plastic polyethylene, placed in an injection molding machine for mixed injection molding, and hot-pressed to obtain a plate-shaped mildew-proof and antibacterial plastic. Preferably, the injection and hot-pressing molding temperature is set to 200°C, and the pressure is set to 15T. In the embodiment of the present invention, the mold can be used to prepare plastic plates of different sizes of 50mm*50mm*10mm. The addition amount of the small molecule-coated silicon nitride monodisperse antibacterial colloid accounts for 0.1-2% of the mass of the mildew-proof and antibacterial plastic.

[0081] Other embodiments of the present invention provide an antibacterial fiber membrane, the preparation raw materials of which include: cellulose acetate and the small molecule-encapsulated silicon nitride monodisperse antibacterial colloid described in any one of the above items; preferably, the nanoscale antibacterial fiber membrane is prepared by electrospinning technology.

[0082] Cellulose acetate has the characteristics of good hydrophilicity and hygroscopicity, and good biocompatibility, and is suitable for wound dressings. In a humid environment, if traditional cotton gauze dressings are not changed frequently, human wounds are prone to breed bacteria, and there is a risk of secondary infection. Cellulose acetate, with its good hygroscopic and biocompatibility characteristics, when used as a medical dressing, avoids secondary damage caused by adhesion to the wound during replacement. The cellulose acetate described in the embodiment of the present invention is industrial grade cellulose acetate, a commercially available product.

[0083] In an embodiment of the present invention, cellulose acetate with good water absorption and small molecule-encapsulated silicon nitride monodisperse antibacterial colloid are combined to give the fiber an effective antibacterial effect, which can avoid the risk of excessive moisture and bacterial infection in the wound healing process, thereby achieving the effect of promoting wound healing.

[0084] Further preferably, the small molecule coated silicon nitride monodisperse antibacterial colloid accounts for 0.5-2% of the mass of the antibacterial fiber film. The antibacterial fiber film of the present invention is a composite silicon nitride component that has been ball-milled and coated with a small molecule reagent added to cellulose acetate with good biocompatibility; compared with the existing traditional cotton gauze dressing, the cellulose acetate film containing silicon nitride is more suitable for use as a dressing, and even in the absence of light, it can generate free electrons and holes to activate oxygen in the air to become active oxygen, which has a good inhibitory effect on bacteria, and at the same time has a more stable antibacterial process, long-lasting antibacterial effect, non-toxic, can effectively promote the healing of human wounds, and will not cause secondary damage to the wounds when used.

[0085] The present invention provides a method for preparing the antibacterial fiber membrane, comprising the following steps:

[0086] S1, dissolving cellulose acetate in a solvent, preferably acetone / DMAc (dimethylacetamide) / water (7 / 2 / 1 w / w / w), to prepare a cellulose acetate spinning solution;

[0087] S2, mixing the small molecule-coated silicon nitride monodisperse antibacterial colloid with the cellulose acetate spinning solution of step S1 at a ratio of 0.5-2%;

[0088] S3. Spin the mixed spinning solution obtained in the above step S2 according to the process parameters (preferably: spinning voltage 15-25 kV, receiving distance 15-20 cm, injection pump flow rate 1-2 ml / h, spinning temperature 20-30°C, relative humidity 45-55%) to obtain an antibacterial fiber membrane.

[0089] In a specific embodiment of the present invention, acetone / DMAc / water (7 / 2 / 1 w / w / w) is used as a solvent, and cellulose acetate is added according to a solute of 10 wt% to obtain a spinning solution. Then, according to a certain addition ratio, the above-mentioned small molecule-coated silicon nitride monodisperse antibacterial colloid is taken and added to the prepared spinning solution, preferably by ultrasonic dispersion, etc., to obtain a uniform mixed spinning solution containing silicon nitride.

[0090] In the embodiment of the present invention, the spinning solution prepared in the above steps is transferred to the spinning needle tube, and the spinning process parameters are set, for example: spinning voltage 15-25kV, receiving distance 15-20cm, injection pump flow rate 1-2ml / h, spinning temperature 20-30°C, relative humidity 45-55%. Preferably, the electrospinning voltage is 17kV, the receiving distance is 18cm, the injection pump flow rate is 1ml / h, the spinning temperature is 25°C, and the relative humidity is 45%; the receiving roller speed can be 90r / min. After the spinning is completed, an antibacterial fiber membrane containing a composite nano antibacterial component is obtained.

[0091] The antibacterial plastic board prepared by the above method is tested for antibacterial performance and mildew resistance, and the glossiness is characterized, etc. The antibacterial fiber film prepared by the above method is tested for antibacterial performance. According to the test results, the antibacterial material in the embodiment of the present invention has the characteristics of good antibacterial effect, etc.

[0092] In order to better understand the technical content of the present invention, the following specific examples are provided to further illustrate the present invention. The following examples use commercially available silicon nitride powder raw materials with a particle size of 300nm-1400nm (actual transmission electron microscope display); the purity is 99.99%, and it is in the form of agglomerates. In addition, the examples of the present invention use polyethylene with a molecular weight of 5000.

[0093] Example 1

[0094] This embodiment provides a small molecule-coated silicon nitride monodisperse antibacterial colloid and a preparation method and a detection method thereof. The specific steps are as follows:

[0095] a. Place the ball milling medium (50 g of 0.1 mm zirconium oxide beads) in a 100 ml ball milling jar, add 0.5 g of commercially available silicon nitride powder, 0.05 g of AR-grade small molecule reagent sodium hexametaphosphate and 50 g of deionized water, set the ball mill (model: UBE-V2L, Hunan Deke Equipment Co., Ltd.) to a speed of 300 r / min, and ball mill for 3 h. After turning off the ball mill, remove the ball milling jar and remove the ball milling medium to obtain a small molecule sodium hexametaphosphate-coated silicon nitride antibacterial colloid; the actual digital photo is shown in FIG. Figure 1 (left) shows the Tyndall effect. Figure 2 .

[0096] b. Take a portion of the above sodium hexametaphosphate-coated silicon nitride antibacterial colloid and drop it directly onto a copper mesh for sample preparation and conduct transmission scanning electron microscopy (TEM) characterization. The results are as follows Figure 3 As shown. And through infrared spectrum analysis, it can be observed that the salts cover the silicon nitride.

[0097] c. Take a portion of the sodium hexametaphosphate-coated silicon nitride antibacterial colloid and perform a minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications, 2002 edition. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0098] The silicon nitride antibacterial colloid prepared in this example is light yellow, and no precipitation occurs after standing for 30 minutes, 1 hour, and 5 hours, and no obvious change occurs after standing for 15 days.

[0099] Comparative Example 1

[0100] This comparative example provides a silicon nitride antibacterial colloid and its preparation method and detection method, which are basically the same as Example 1 and also undergo ball milling treatment, the main difference being that sodium hexametaphosphate is not added. The specific steps are as follows:

[0101] a. Place the ball milling medium (50 g of 0.1 mm zirconium oxide beads) in a 100 ml ball milling jar, accurately weigh 0.5 g of commercially available silicon nitride powder, mix it with 50 g of deionized water, set the ball mill (model: UBE-V2L, Hunan Deke Equipment Co., Ltd.) to a speed of 300 r / min, and mill for 3 h. After turning off the ball mill, remove the ball milling jar and remove the ball milling medium. The resulting colloid is shown in the digital photo. Figure 1 (right) shown.

[0102] b. Take a portion of the above silicon nitride antibacterial colloid and perform a minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications 2002. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0103] By comparison:

[0104] Figure 1 In the experiment, the unmodified silicon nitride precipitated after standing for 10 minutes, and obvious stratification appeared after 48 hours, indicating that the dispersion effect of the unmodified nitride colloidal body was not good. However, the silicon nitride after mechanical-chemical modification with sodium hexametaphosphate did not precipitate after standing for 48 hours, and it was still in a uniform state, indicating that the silicon nitride after mechanical-chemical modification with sodium hexametaphosphate can be stably dispersed in the aqueous reagent to form a uniform and transparent colloid.

[0105] Example 2

[0106] This embodiment provides a small molecule coated silicon nitride monodisperse antibacterial colloid and its preparation method and detection method, which are basically the same as those in Example 1, except that the dispersant addition ratio and process parameters are different. The specific steps are as follows:

[0107] a. Place the ball milling medium (50 g of 0.1 mm zirconium oxide beads) in a 100 ml ball mill, add 0.5 g of commercially available silicon nitride powder, 0.05 g of AR-grade small molecule reagent sodium hexametaphosphate, 0.05 g of sodium dodecylbenzene sulfonate and 50 g of deionized water, set the ball mill (model: UBE-V2L, Hunan Deke Equipment Co., Ltd.) to a speed of 500 r / min, and ball mill for 3 h. After turning off the ball mill, remove the ball mill and remove the ball milling medium to obtain small molecule (sodium hexametaphosphate, sodium dodecylbenzene sulfonate)-coated silicon nitride antibacterial colloid.

[0108] b. It was observed that the small molecule coated silicon nitride antibacterial colloid prepared in this example was more uniform than the sodium hexametaphosphate coated silicon nitride antibacterial colloid prepared in Example 1. The silicon nitride antibacterial colloid prepared in this example was light yellow, and no precipitation appeared after standing for 30 minutes, 1 hour, and 5 hours, and no obvious change after standing for 15 days.

[0109] c. Take a portion of the above small molecule coated silicon nitride antibacterial colloid and perform the minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications 2002. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0110] Comparative Example 2

[0111] This comparative example provides a silicon nitride antibacterial colloid and its preparation method and detection method, which are basically the same as Example 2, except that the mechanical stirring method is used instead of the ball milling step. The specific steps are as follows:

[0112] a. Mix 0.5g of commercially available silicon nitride powder, 0.05g of AR-grade small molecule reagent sodium hexametaphosphate, 0.05g of sodium dodecylbenzene sulfonate and 50g of deionized water, place in a 50ml beaker, and stir at high speed for 1h at a speed of 500r / min to obtain silicon nitride antibacterial colloid. Let the sample stand for 10min until precipitation and obvious stratification appear at the bottom.

[0113] b. The particle size analyzer test showed that the aqueous antibacterial silicon nitride colloid prepared in this comparative example had colloid particles larger than 300 nm compared with the small molecule coated silicon nitride antibacterial colloid prepared by ball milling in Example 2.

[0114] c. Take a portion of the above silicon nitride antibacterial colloid and perform a minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications 2002. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0115] Example 3

[0116] This embodiment provides a small molecule coated silicon nitride monodisperse antibacterial colloid and its preparation method and detection method, which are basically the same as those in Example 1, except that the dispersant addition ratio and process parameters are different. The specific steps are as follows:

[0117] a. Place the ball milling medium (50 g of 0.1 mm zirconium oxide beads) in a 100 ml ball mill, add 0.5 g of commercially available silicon nitride powder, 0.05 g of AR-grade small molecule reagent sodium hexametaphosphate, 0.05 g of polyethylene glycol (molecular weight 4000-6000) and 50 g of deionized water, set the ball mill (model: UBE-V2L, Hunan Deke Equipment Co., Ltd.) to a speed of 600 m / min, ball mill for 4 h, close the ball mill, remove the ball mill, remove the ball milling medium, and obtain small molecule (sodium hexametaphosphate, polyethylene glycol) coated silicon nitride antibacterial colloid.

[0118] b. It was observed that the small molecule coated silicon nitride antibacterial colloid prepared in this example was more transparent and uniform than the sodium hexametaphosphate coated silicon nitride antibacterial colloid prepared in Example 1. The silicon nitride antibacterial colloid prepared in this example was light yellow, and no precipitation appeared after standing for 30 minutes, 1 hour, and 5 hours, and no obvious change after standing for 15 days.

[0119] c. Take a portion of the above small molecule coated silicon nitride antibacterial colloid and perform the minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications 2002. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0120] Comparative Example 3

[0121] This comparative example provides a silicon nitride antibacterial colloid and its preparation method and detection method, which are basically the same as Example 3, except that the ultrasonic dispersion method is used instead of the ball milling step. The specific steps are as follows:

[0122] a. Mix 0.5g of commercially available silicon nitride powder, 0.05g of AR-grade small molecule reagent sodium hexametaphosphate, 0.05g of polyethylene glycol and 50g of deionized water, place in a 50ml sample bottle, and ultrasonically disperse for 30 minutes to obtain silicon nitride antibacterial colloid. Let the sample stand for 10 minutes until precipitation and obvious stratification appear at the bottom.

[0123] b. The particle size analyzer test showed that the silicon nitride antibacterial colloid prepared in this comparative example had colloid particles larger than 300 nm compared with the small molecule coated silicon nitride antibacterial colloid prepared in Example 3.

[0124] c. Take a portion of the above silicon nitride antibacterial colloid and perform a minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications 2002. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0125] Example 4

[0126] This embodiment provides a small molecule coated silicon nitride antibacterial colloid and its preparation method and detection method, which are basically the same as those in Example 1, except that the process parameters are different. The specific steps are as follows:

[0127] a. Place the ball milling medium (50 g of 0.1 mm zirconium oxide beads) in a 100 ml ball mill, add 0.5 g of commercially available silicon nitride powder, 0.05 g of AR-grade small molecule reagent sodium hexametaphosphate, 0.05 g of sodium tripolyphosphate and 50 g of deionized water, set the ball mill (model: UBE-V2L, Hunan Deke Equipment Co., Ltd.) to a speed of 700 m / min, ball mill for 4 h, close the ball mill, remove the ball mill, remove the ball milling medium, and obtain a small molecule-coated silicon nitride monodisperse antibacterial colloid.

[0128] b. It was observed that the small molecule coated silicon nitride antibacterial colloid prepared in this example was more uniform than the sodium hexametaphosphate coated silicon nitride antibacterial colloid prepared in Example 1. The silicon nitride antibacterial colloid prepared in this example was light yellow and showed a very obvious "Tyndall effect". No precipitation appeared after standing for 30 minutes, 1 hour, and 5 hours, and no obvious change after standing for 15 days.

[0129] c. Take a portion of the above small molecule coated silicon nitride antibacterial colloid and perform the minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications 2002. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0130] Example 5

[0131] This embodiment provides a small molecule coated silicon nitride antibacterial colloid and its preparation method and detection method, which are basically the same as those in Example 1, except that the process parameters are different. The specific steps are as follows:

[0132] a. Place the ball milling medium (50 g of 0.1 mm zirconium oxide beads) in a ball milling jar with a volume of 100 ml, add 0.5 g of commercially available silicon nitride powder, 0.05 g of AR-grade small molecule reagent sodium hexametaphosphate, 0.01 g of sodium dodecylbenzene sulfonate, 0.01 g of polyethylene glycol, 0.01 g of sodium tripolyphosphate and 50 g of deionized water, set the ball mill (model: UBE-V2L, Hunan Deke Equipment Co., Ltd.) to a speed of 700 m / min, ball mill for 5 h, close the ball milling jar, remove the ball milling medium, and obtain a small molecule-coated silicon nitride monodisperse antibacterial colloid.

[0133] b. It was observed that the small molecule coated silicon nitride antibacterial colloid prepared in this example was more uniform than the sodium hexametaphosphate coated silicon nitride antibacterial colloid prepared in Example 1. The silicon nitride antibacterial colloid prepared in this example was light yellow and showed a very obvious "Tyndall effect". No precipitation appeared after standing for 30 minutes, 1 hour, and 5 hours, and no obvious change after standing for 15 days.

[0134] c. Take a portion of the above small molecule coated silicon nitride antibacterial colloid and perform the minimum inhibitory concentration test according to 2.1.8.4 of the Disinfection Technical Specifications 2002. Test bacteria: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213. The test results are summarized in Tables 1 and 2.

[0135] Table 1 Antibacterial effect of the colloids of the present invention on Staphylococcus aureus

[0136]

[0137] Table 2 Antibacterial effect of the colloids of the present invention on Escherichia coli

[0138]

[0139]

[0140] As can be seen from Table 1 and Table 2, in Comparative Example 1, the commercially available silicon nitride (particle size of 60-100nm, purity of 99.99%) itself has weak antibacterial properties, and its minimum inhibitory concentration (MIC) for Escherichia coli is above 2496ppm, and its minimum inhibitory concentration (MIC) for Staphylococcus aureus is above 1248ppm. The nitride colloidal bodies of Examples 1-5, which have been ball-milled and chemically modified by small molecule reagents, have excellent antibacterial properties, especially the minimum inhibitory concentration (MIC) for Staphylococcus aureus of Example 5 is 39ppm, and the minimum inhibitory concentration for Escherichia coli is 78ppm. This indicates that the particle size of silicon nitride becomes smaller after the mechanical-chemical modification of silicon nitride by small molecule coating, and at the same time, due to the synergistic antibacterial effect of small molecule dispersant and silicon nitride, the well-dispersed nitride colloidal bodies have a more excellent antibacterial effect.

[0141] Compared with mixing silicon nitride, a small molecule dispersant, and water and then stirring, or ultrasonic stirring, the present invention adds a ball milling process to mix the three, effectively coating the small molecule dispersant on silicon nitride, and the prepared nitride colloidal body has better dispersibility and is more uniform. After the prepared nitride colloidal body in the embodiment of the present invention is centrifuged at 8000r / min, the colloid has no precipitation and obvious changes, indicating that the nitride colloidal body can be stably stored for a long time, and the antibacterial performance is also better, which is conducive to the application in antibacterial products.

[0142] Example 6

[0143] This embodiment provides a mildew-proof and antibacterial plastic and a preparation method and a detection method thereof, and the specific steps are as follows:

[0144] a. The small molecule-coated antibacterial silicon nitride colloid prepared in Example 5 was centrifuged, dried in an oven at 80°C for 24 hours, ground and sieved through 200 mesh to obtain antibacterial silicon nitride powder.

[0145] b. Weigh the above-mentioned antibacterial silicon nitride powder at a dosage of 0.5%, add it to ordinary plastic polyethylene and mix evenly, and obtain antibacterial masterbatch containing silicon nitride after extrusion, wire drawing, water cooling and granulation in a granulator. The twin-screw extrusion temperature is 180°C, 200°C, 210°C, the extrusion speed is 18r / min, and the pelletizer speed is 12r / min.

[0146] c. Take a portion of the dried silicon nitride antibacterial masterbatch, mix it evenly with ordinary plastic polyethylene, put it in an injection molding machine for mixed injection molding, and hot press molding to obtain an antibacterial plastic plate. Set the hot press temperature to 200°C and the pressure to 15T.

[0147] d. Take the antibacterial plastic plate prepared in the above steps, and test the antibacterial and mildew-proof properties according to the standards "Test Method for Antibacterial Performance of Plastic Surfaces" (GB / T 31402-2015) and "Evaluation of the Antibacterial Effect of Plastic Antifungal Agents" (GB / T24128-2018). The test bacteria are: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213; Aspergillus niger, Chaetomium globosum, Penicillium variotii, Penicillium funiculum, and Trichoderma longibrachiatum.

[0148] e. The test results are summarized in Table 3.

[0149] Example 7

[0150] This embodiment provides a mildew-proof and antibacterial plastic and a preparation method and a detection method thereof, which are basically the same as those in Embodiment 6, except that the addition ratio of silicon nitride antibacterial powder is different. The specific steps are as follows:

[0151] a. The small molecule-coated antibacterial silicon nitride colloid prepared in Example 5 was centrifuged, dried in an oven at 80°C for 24 hours, ground and sieved through 200 mesh to obtain antibacterial silicon nitride powder.

[0152] b. Weigh the above-mentioned silicon nitride antibacterial powder according to a 1% addition amount, add it to ordinary plastic polyethylene and mix evenly, and obtain the antibacterial masterbatch containing silicon nitride after extrusion, wire drawing, water cooling and granulation in a granulator. The twin-screw extrusion temperature is 180°C, 200°C, 210°C, the extrusion speed is 18r / min, and the pelletizer speed is 12r / min.

[0153] c. Take a portion of the dried silicon nitride antibacterial masterbatch, mix it evenly with ordinary plastic polyethylene, put it in an injection molding machine for mixed injection molding, and hot press molding to obtain an antibacterial plastic plate. Set the hot press temperature to 200°C and the pressure to 15T.

[0154] d. Take the antibacterial plastic plate prepared in the above steps, and test the antibacterial and mildew-proof properties according to the standards "Test Method for Antibacterial Performance of Plastic Surfaces" (GB / T 31402-2015) and "Evaluation of the Antibacterial Effect of Plastic Antifungal Agents" (GB / T24128-2018). The test bacteria are: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213; Aspergillus niger, Chaetomium globosum, Penicillium variotii, Penicillium funiculum, and Trichoderma longibrachiatum.

[0155] e. The test results are summarized in Table 3.

[0156] Example 8

[0157] This embodiment provides a mildew-proof and antibacterial plastic and a preparation method and a detection method thereof, which are basically the same as those in Embodiment 6, except that the addition ratio of silicon nitride antibacterial powder is different. The specific steps are as follows:

[0158] a. The small molecule-coated antibacterial silicon nitride colloid prepared in Example 5 was centrifuged, dried in an oven at 80°C for 24 hours, ground and sieved through 200 mesh to obtain antibacterial silicon nitride powder.

[0159] b. Weigh the above-mentioned antibacterial silicon nitride powder at a 1.5% addition amount, add it to ordinary plastic polyethylene and mix evenly, and obtain antibacterial masterbatch containing silicon nitride after extrusion, wire drawing, water cooling and granulation in a granulator. The twin-screw extrusion temperature is 180°C, 200°C, 210°C, the extrusion speed is 18r / min, and the pelletizer speed is 12r / min.

[0160] c. Take a portion of the dried silicon nitride antibacterial masterbatch, mix it evenly with ordinary plastic polyethylene, put it in an injection molding machine for mixed injection molding, and hot press molding to obtain an antibacterial plastic plate. Set the hot press temperature to 200°C and the pressure to 15T.

[0161] d. Take the antibacterial plastic plate prepared in the above steps, and test the antibacterial and mildew-proof properties according to the standards "Test Method for Antibacterial Performance of Plastic Surfaces" (GB / T 31402-2015) and "Evaluation of the Antibacterial Effect of Plastic Antifungal Agents" (GB / T24128-2018). The test bacteria are: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213; Aspergillus niger, Chaetomium globosum, Penicillium variotii, Penicillium funiculum, and Trichoderma longibrachiatum.

[0162] e. The test results are summarized in Table 3.

[0163] Comparative Example 4

[0164] This comparative example provides a preparation method and detection method of a mildew-proof and antibacterial plastic comparative sample, which is basically the same as Example 6, except that no antibacterial agent is added to the polyethylene. The specific steps are as follows:

[0165] a. Take ordinary plastic polyethylene, place it in an injection molding machine for injection molding, and heat press molding to obtain an antibacterial plastic plate. Set the hot pressing temperature to 200℃ and the pressure to 15T.

[0166] b. Take the plastic plate made in the above steps, and test the antibacterial and mildew-proof properties according to the standard "Test Method for Antibacterial Performance of Plastic Surface" (GB / T 31402-2015) and "Evaluation of Antibacterial Effect of Plastic Antifungal Agents" (GB / T24128-2018). The test bacteria are: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213; Aspergillus niger, Chaetomium globosum, Penicillium variotii, Penicillium funiculum, and Trichoderma longibrachiatum.

[0167] c. The test results are summarized in Table 3.

[0168] Figure 4 These are digital photos of the plastics of Example 6 (left) and Comparative Example 4 (right). It can be seen that the anti-mildew and antibacterial plastics to which small molecule-encapsulated silicon nitride monodisperse antibacterial colloids are added have no obvious difference in appearance from ordinary plastics.

[0169] Table 3 Anti-mildew and antibacterial effects of plastics of the present invention

[0170]

[0171]

[0172] According to the test results, it can be seen from Comparative Example 4 and Example 6 that the plastic sample with added silicon nitride antibacterial powder has good antibacterial and mildew-proof effects. When the amount of silicon nitride antibacterial powder added is 0.5%, the antibacterial rate of the coating against Staphylococcus aureus can reach 98.9%, and the antibacterial rate against Escherichia coli can reach 97.0%; the plastic sample with added silicon nitride antibacterial powder was observed under a microscope (magnification 50 times) without mold growth, while the plastic sample without added silicon nitride antibacterial powder had obvious mold growth.

[0173] Example 9

[0174] This embodiment provides an antibacterial fiber membrane and a preparation method and a detection method thereof, and the specific steps are as follows:

[0175] a. According to the solute content of 10%, cellulose acetate was added to a solution with acetone / DMAc / water (7 / 2 / 1 w / w / w) as solvent, and the small molecule-encapsulated silicon nitride antibacterial colloid prepared in Example 5 was weighed according to the addition amount of 0.5%, and added to the prepared spinning solution, and ultrasonically dispersed for 30 minutes. The mixed system was stirred at 250r / min in a constant temperature water bath at 60°C for 1 hour, and a bubble-free transparent spinning solution containing silicon nitride was obtained after standing.

[0176] b. Take the spinning solution prepared in the above steps, transfer it to the spinning needle tube, set the spinning process parameters of 17kV wire voltage, 18cm receiving distance, 1ml / h injection pump flow rate, 25℃ spinning temperature, 45% relative humidity, and 90r / min receiving roller speed. After spinning, an antibacterial fiber membrane containing silicon nitride is obtained.

[0177] c. Take the antibacterial fiber membrane prepared in the above steps, and test the antibacterial and antifungal properties according to the standard "Evaluation of Antibacterial Properties of Textiles" (GB / T20944). The tested bacteria are: Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC29213.

[0178] d. The test results are summarized in Table 4.

[0179] Example 10

[0180] This embodiment provides an antibacterial fiber membrane and a preparation method and a detection method thereof, which are basically the same as those in Embodiment 9, except that the addition ratio of the small molecule-coated silicon nitride antibacterial colloid is different. The specific steps are as follows:

[0181] a. According to the solute content of 10%, cellulose acetate was added to a solution with acetone / DMAc / water (7 / 2 / 1 w / w / w) as solvent, and the small molecule-coated silicon nitride antibacterial colloid prepared in Example 5 was weighed according to the addition amount of 1%, and added to the prepared spinning solution, and ultrasonically dispersed for 30 minutes. The mixed system was stirred at 250r / min in a constant temperature water bath at 60°C for 1 hour, and a bubble-free transparent spinning solution containing silicon nitride was obtained after standing.

[0182] b. Take the spinning solution prepared in the above steps, transfer it to the spinning needle tube, set the spinning process parameters of 17kV wire voltage, 18cm receiving distance, 1ml / h injection pump flow rate, 25℃ spinning temperature, 45% relative humidity, and 90r / min receiving roller speed. After spinning, an antibacterial fiber membrane containing silicon nitride is obtained.

[0183] c. Take the antibacterial fiber membrane prepared in the above steps, and test the antibacterial and antifungal properties according to the standard "Evaluation of Antibacterial Properties of Textiles" (GB / T20944). The tested bacteria are: Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC29213.

[0184] d. The test results are summarized in Table 4.

[0185] Embodiment 11

[0186] This embodiment provides an antibacterial fiber membrane and a preparation method and a detection method thereof, which are basically the same as those in Embodiment 9, except that the addition ratio of the small molecule-coated silicon nitride antibacterial colloid is different. The specific steps are as follows:

[0187] a. According to the solute content of 10%, cellulose acetate was added to a solution with acetone / DMAc / water (7 / 2 / 1 w / w / w) as solvent, and the small molecule-coated silicon nitride antibacterial colloid prepared in Example 5 was weighed according to the addition amount of 1.5%, and added to the prepared spinning solution, and ultrasonically dispersed for 30 minutes. The mixed system was stirred at 250r / min in a constant temperature water bath at 60°C for 1 hour, and a bubble-free transparent spinning solution containing silicon nitride was obtained after standing.

[0188] b. Take the spinning solution prepared in the above steps, transfer it to the spinning needle tube, set the spinning process parameters of 17kV wire voltage, 18cm receiving distance, 1ml / h injection pump flow rate, 25℃ spinning temperature, 45% relative humidity, and 90r / min receiving roller speed. After spinning, an antibacterial fiber membrane containing silicon nitride is obtained.

[0189] c. Take the antibacterial fiber membrane prepared in the above steps, and test the antibacterial and antifungal properties according to the standard "Evaluation of Antibacterial Properties of Textiles" (GB / T20944). The tested bacteria are: Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC29213.

[0190] d. The test results are summarized in Table 4.

[0191] Example 12

[0192] This embodiment provides an antibacterial fiber membrane and a preparation method and a detection method thereof, which are basically the same as those in Embodiment 9, except that the addition ratio of the small molecule-coated silicon nitride antibacterial colloid is different. The specific steps are as follows:

[0193] a. According to the solute content of 10%, cellulose acetate was added to a solution with acetone / DMAc / water (7 / 2 / 1 w / w / w) as solvent, and the small molecule-coated silicon nitride antibacterial colloid prepared in Example 5 was weighed according to the addition amount of 2%, and added to the prepared spinning solution, and ultrasonically dispersed for 30 minutes. The mixed system was stirred at 250r / min in a constant temperature water bath at 60°C for 1 hour, and a bubble-free transparent spinning solution containing silicon nitride was obtained after standing.

[0194] b. Take the spinning solution prepared in the above steps, transfer it to the spinning needle tube, set the spinning process parameters of 17kV wire voltage, 18cm receiving distance, 1ml / h injection pump flow rate, 25℃ spinning temperature, 45% relative humidity, and 90r / min receiving roller speed. After spinning, an antibacterial fiber membrane containing silicon nitride is obtained.

[0195] c. Take the antibacterial fiber membrane prepared in the above steps, and test the antibacterial and antifungal properties according to the standard "Evaluation of Antibacterial Properties of Textiles" (GB / T20944). The tested bacteria are: Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC29213.

[0196] d. The test results are summarized in Table 4.

[0197] Comparative Example 5

[0198] This comparative example provides a preparation method and detection method of an antibacterial fiber membrane comparative sample, which is basically the same as Example 9, except that no antibacterial agent is added to cellulose acetate. The specific steps are as follows:

[0199] a. Add cellulose acetate to a solution with acetone / DMAc / water (7 / 2 / 1 w / w / w) as solvent at a solute content of 10%, stir the mixed system at 250 r / min in a constant temperature water bath at 60°C for 1 hour, and prepare a bubble-free transparent spinning solution after standing.

[0200] b. Take the spinning solution prepared in the above steps, transfer it to the spinning needle tube, set the spinning process parameters to 17kV of spinning voltage, 18cm of receiving distance, 1ml / h of injection pump flow rate, 25℃ of spinning temperature, 45% of relative humidity, and 90r / min of receiving roller speed. After spinning, a fiber membrane is obtained.

[0201] c. Take the fiber membrane prepared in the above steps and test the antibacterial and antifungal properties according to the standard "Evaluation of Antibacterial Properties of Textiles" (GB / T20944). The tested bacteria are: Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213.

[0202] d. The test results are summarized in Table 4.

[0203] Figure 5 These are digital photos of the fiber membranes of Example 9 (left) and Comparative Example 5 (right); it can be seen that the antibacterial fiber membrane to which small molecule-encapsulated silicon nitride monodisperse antibacterial colloid is added has no obvious difference in appearance from the ordinary fiber membrane.

[0204] Table 4 Antibacterial effect of the fiber membrane of the embodiment of the present invention

[0205]

[0206] According to the test results, it can be seen from Comparative Example 5 and Example 9 that the cellulose film with the addition of silicon nitride antibacterial agent has a good antibacterial effect. When the addition amount of silicon nitride antibacterial agent is 0.5%, the antibacterial rate of the coating against Staphylococcus aureus can reach 99.1%, and the antibacterial rate against Escherichia coli can reach 97.2%; while the cellulose film without the addition of silicon nitride antibacterial agent has no antibacterial performance.

[0207] It can be seen from the above embodiments that the particle size of the antibacterial colloidal silicon nitride is optimized by the method of the embodiment of the present invention, the dispersion performance of this material in water is improved, and the size of the material can be stable for a long time. The small molecules described in the present invention are coated with silicon nitride particles by a mechanical-chemical modification method to reduce the effects of van der Waals forces, electrostatic attraction, etc. between the particles. At the same time, the antibacterial properties of the obtained colloid are studied, and the colloid has good antibacterial properties against both Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Furthermore, the small molecule-coated silicon nitride monodisperse antibacterial colloid also has the characteristics of high temperature resistance, good durability, stability and non-toxicity, which is conducive to its application in the preparation of antibacterial materials.

[0208] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0209] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A small molecule coated silicon nitride monodisperse antibacterial colloid, characterized in that: The invention relates to monodisperse particles of small molecule-coated silicon nitride, wherein the small molecule-coated silicon nitride monodisperse antibacterial colloid is formed by high-energy ball milling of silicon nitride, a small molecule dispersant and water; the mass ratio of silicon nitride to water is 1:100-1:9000; and the mass ratio of silicon nitride to the small molecule dispersant is 1:1-10:1; The small molecule dispersant is selected from hexametaphosphate; Alternatively, the small molecule dispersant comprises hexametaphosphate and a small molecule auxiliary agent, and the small molecule auxiliary agent is selected from one or more of dodecylbenzene sulfonate, polyethylene glycol and tripolyphosphate.

2. The method for preparing the small molecule-coated silicon nitride monodisperse antibacterial colloid as claimed in claim 1 comprises the following steps: Silicon nitride, a small molecule dispersant, water and a ball milling medium are mixed, high-energy ball milling is performed, and then the ball milling medium is removed to obtain a small molecule-coated silicon nitride monodisperse antibacterial colloid.

3. The preparation method according to claim 2, characterized in that: The rotation speed of the high energy ball mill is 200 r / min-800 r / min; and / or, the temperature of the high energy ball mill is 20° C.-50° C.; and / or, the ball milling medium is zirconia beads with a particle size of 0.1 mm-0.5 mm.

4. Use of the small molecule coated silicon nitride monodisperse antibacterial colloid as claimed in claim 1 in the preparation of antibacterial materials.

5. A mildew-proof and antibacterial plastic, the raw materials for its preparation include: Ordinary plastic polyethylene and the small molecule coated silicon nitride monodisperse antibacterial colloid according to claim 1.

6. The mildew-proof and antibacterial plastic according to claim 5, characterized in that: The addition amount of the small molecule coated silicon nitride monodisperse antibacterial colloid accounts for 0.1-2% of the mass of the mildew-proof and antibacterial plastic.

7. An antibacterial fiber membrane, the raw materials for preparation include: Cellulose acetate and the small molecule-coated silicon nitride monodisperse antibacterial colloid according to claim 1.

8. The antibacterial fiber membrane according to claim 7, characterized in that: The small molecule coated silicon nitride monodisperse antibacterial colloid accounts for 0.5-2% of the mass of the antibacterial fiber membrane.

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