Silver / plant essential oil synergistic antibacterial non-woven fabric and preparation method thereof

Abstract

The invention belongs to the technical field of functional non-woven materials, and particularly relates to a silver / plant essential oil synergistic antibacterial non-woven fabric and a preparation method thereof. According to the non-woven fabric, modified silver-containing short fibers and main body fibers are mixed and reinforced through hot air to form basic non-woven fabric; a core material formed by compounding lavandula angustifolia, piper nigrum, tea trees and chamomile essential oil according to a specific proportion is microencapsulated through a gelatin-Arabic gum-sodium alginate composite wall material, and then the core material is finished on a basic non-woven fabric through an electrostatic spraying technology. According to the invention, inorganic silver antibiosis and natural plant essential oil antibiosis are organically combined, efficient and uniform loading of the microcapsule is realized by utilizing electrostatic spraying, and the problems that the silver component is easy to fall off, the essential oil is easy to volatilize, the function is single and not durable and the like are solved. The obtained product has the advantages of efficient synergistic antibiosis, lasting slow release and good air permeability, and is suitable for sanitary care products such as sanitary napkins and paper diapers.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional non-woven materials, and particularly relates to a silver / plant essential oil synergistic antibacterial non-woven fabric and a preparation method thereof. BACKGROUND

[0002] The non-woven fabric produced by the hot air method is widely used in the field of health care due to its soft hand feeling, high bulkiness, good air permeability and other advantages, especially sanitary napkins, paper diapers, wet wipes and other products which are in direct contact with the skin. With the improvement of people's health consciousness, consumers not only pay attention to the basic use performance of products, but also put forward higher requirements for their comfort and functionality, such as antibacterial, soothing and other additional effects.

[0003] At present, the common way to give non-woven fabric antibacterial function is to add antibacterial agents during the preparation process or to introduce antibacterial agents in the finishing stage. According to the nature of the antibacterial agent, it can be divided into two categories: organic antibacterial agent and inorganic antibacterial agent. Organic antibacterial agents, such as quaternary ammonium salt compounds, although the initial antibacterial effect is significant, but in practical use, there is a common problem of insufficient durability, and after several washes or long-term storage, its antibacterial efficiency is easy to decay. More worth noting is that long-term or improper use of some organic antibacterial agents may induce microbial resistance, thereby reducing its long-term protection effect and bringing potential ecological and health risks.

[0004] In contrast, inorganic antibacterial agents represented by silver-based antibacterial agents have been widely used due to their broad-spectrum, high-efficiency antibacterial properties and the characteristics of not easily inducing drug resistance. Usually, silver ions or nano-silver are loaded on the surface or inside of the fiber to realize functionalization. However, this kind of loaded silver antibacterial non-woven fabric has some limitations in practical application. On the one hand, the binding strength between silver ions and fibers is limited, and when subjected to friction or washing, silver components are easy to fall off, resulting in a decrease in antibacterial durability and possibly affecting the safety of product use. On the other hand, if the silver component is enriched on the surface of the non-woven fabric, it may affect the skin-friendly touch of the material to some extent, making it feel hard or wet and cold, which is not good for the comfort experience of sensitive skin groups such as infants, women, etc.

[0005] In recent years, plant essential oils derived from nature have been favored in the field of functional textiles due to their broad-spectrum antibacterial, anti-inflammatory and soothing skin effects, as well as their natural and safe image. However, plant essential oils have the characteristics of easy volatilization and unstable chemical properties, and if they are directly loaded on non-woven fabrics by impregnation or coating, the essential oils will quickly volatilize and lose, making it difficult to maintain their functionality. At the same time, there is a lack of strong binding force between essential oils and fiber substrates, which may be lost in large quantities in the early stage of use.

[0006] The prior art has not yet been able to provide an ideal solution that can effectively combine the durability of inorganic silver antibacterial agent with the broad-spectrum antibacterial and soothing advantages of natural plant essential oil, while ensuring that the function is durable, evenly distributed, and does not affect the original soft and breathable properties of the non-woven fabric. Therefore, it has become a technical problem to be solved in the field to develop an innovative process and material system to achieve the perfect integration of high-efficiency multi-antibacterial and skin-soothing functions, and to have good durability and use comfort. SUMMARY

[0007] The purpose of the present application is to provide a silver / plant essential oil synergistic antibacterial non-woven fabric and a preparation method thereof, aiming to realize the synergistic antibacterial effect of silver ions and plant essential oil, while giving the product durable antibacterial efficiency, excellent soothing performance, and good air permeability and soft hand feeling.

[0008] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions: The first aspect of the present application provides a preparation method of a silver / plant essential oil synergistic antibacterial non-woven fabric, comprising the following steps: (1) mixing a main fiber and a modified silver-containing short fiber, carding into a fiber web with a grammage of 20-45 g / m 2 , and then hot air reinforcing the fiber web to obtain a silver-containing basic non-woven fabric; (2) preparing a compound essential oil microcapsule finishing liquid, and electrostatically spraying the finishing liquid onto the silver-containing basic non-woven fabric of step (1); the compound essential oil comprises Lavandula latifolia Medik. essential oil, Piper methysticum G. Forst. essential oil, Melaleuca alternifolia (Maiden & Betche) Cheel essential oil, and Matricaria chamomilla L. essential oil; (3) drying the non-woven fabric electrostatically sprayed in step (2) to obtain the silver / plant essential oil synergistic antibacterial non-woven fabric.

[0009] Further, the main fiber in step (1) is one or both of polyethylene / polypropylene composite fiber (ES) and polypropylene fiber (PP).

[0010] Further, the modified silver-containing short fiber in step (1) is prepared according to the following method: (i) taking polyethylene (PE) or polypropylene (PP) short fiber as a substrate, and immersing it in a chitosan-acetic acid aqueous solution with a mass concentration of 5-15% at 60-80°C for 30-60 minutes; (ii) the impregnated fiber is taken out and immersed in a 0.1-0.5 mol / L silver nitrate (AgNO3) solution, under ultrasonic oscillation, a reducing agent ascorbic acid is added dropwise, the molar ratio of ascorbic acid to silver nitrate is controlled to be (1-1.2):1, and the reaction is carried out at 50-70℃ for 1-3 hours; (iii) after the reaction is completed, the fiber is washed to neutral, dried, and the modified silver-containing short fiber is obtained.

[0011] Further, the polyethylene (PE) or polypropylene (PP) short fiber in step (i) has a fineness of 1.5-3.5D and a length of 30-60mm.

[0012] Further, the mass of the modified silver-containing short fiber in step (1) accounts for 1-10% of the total mass of the fiber.

[0013] Further, the temperature of the hot air reinforcement in step (1) is 120-160℃, the wind speed is 0.5-2.0 m / s, and the hot air reinforcement time is 1-3 minutes.

[0014] The modified silver-containing short fiber of the present application constructs a stable fiber-biopolymer-nano silver ternary composite structure through a chitosan-in situ reduction process. The chitosan film layer is first tightly coated on the surface of the fiber through adsorption and winding, and the abundant amino and hydroxyl groups on the molecular chain provide a large number of uniform active sites for the subsequent complexation and reduction of silver ions; under the assistance of ultrasonic oscillation, ascorbic acid reduces silver ions in situ into nano-sized silver particles, which are firmly anchored inside the chitosan network and on the surface of the fiber, rather than simply physically attached. This structure fundamentally solves the problem of easy peeling and poor water washing and abrasion resistance of traditional silver-plated fibers due to the weak bonding force between the silver layer and the fiber, ensuring the durability of the antibacterial component. At the same time, chitosan itself is a natural cationic polymer with inherent antibacterial activity, and when it and nano silver contact microorganisms, they can produce a double action mechanism, damaging the cell membrane and interfering with metabolism, significantly improving the antibacterial efficiency. In addition, this nano silver form coated by chitosan has a more moderate and controllable release behavior than bare silver particles, not only prolonging the action time, but also reducing the negative impact on the skin-friendly feel of the product, laying a stable and long-acting foundation for subsequent synergistic action with plant essential oils.

[0015] Further, the mass ratio of the spike lavender essential oil, kava pepper essential oil, tea tree essential oil and chamomile essential oil in step (2) is (3.0 ~ 4.0) : 1 : (1.5 ~ 2.5) : (0.8 ~ 1.2).

[0016] Further, the compound essential oil microcapsule finishing liquid in step (2) is prepared according to the following method: (a) A mixture of spike lavender essential oil, kava essential oil, tea tree essential oil and chamomile essential oil was used as the core material, and a composite system of gelatin, gum arabic and sodium alginate was used as the wall material. The mixture was encapsulated using the complex coagulation method, and the mass ratio of the core material to the wall material was controlled to be 1: (1-4) to prepare compound essential oil microcapsules. (b) The compound essential oil microcapsules were dispersed in deionized water, and waterborne polyurethane dispersion (WPU) was added as a binder and penetrant JFC. The mixture was stirred to obtain the compound essential oil microcapsule finishing solution.

[0017] Further, in step (a), the mass ratio of gelatin, gum arabic and sodium alginate is 1:(0.8~1.2):(0.1~0.3); in step (b), the amount of waterborne polyurethane dispersion is 5%-15% of the mass of microcapsules, and the amount of penetrant JFC is 0.1%-0.5% of the total mass of finishing liquid.

[0018] In this compound essential oil formula, Spike lavender essential oil, with its high content of linalool and linalyl acetate, provides a broad-spectrum and potent antibacterial base and exhibits excellent soothing properties for the skin. Kava pepper essential oil, with its kava lactone components, not only effectively soothes skin discomfort but also preferentially acts on the lipid structure of microbial cell membranes, increasing their permeability. This creates a significant advantage for the transmembrane transport and intracellular penetration of silver ions in the system, resulting in a deep synergistic antibacterial effect through membrane-breaking and penetration with silver fibers. Tea tree essential oil, as an adjunct, enhances the targeted clearance of specific pathogens with its abundant terpinen-4-ol. Chamomile essential oil, through its anti-inflammatory components such as bisabolol, balances the overall formula's irritation and enhances its soothing and repairing functions. The combination of these four essential oils in a specific ratio creates a complementary and synergistic effect in terms of antibacterial spectrum, target sites, and soothing dimensions. Microencapsulation, as a carrier technology, mainly solves the physical defects of this complex essential oil system, such as volatility and instability, ensuring that it can be uniformly and stably loaded on non-woven fabric and achieve slow release, so that this specific chemical synergy can be continuously and stably exerted throughout the product's entire lifespan.

[0019] Further, the process parameters for electrostatic spraying in step (2) are: voltage 30-80 kV, liquid flow rate 5-20 mL / min, distance between the nozzle and the nonwoven fabric 15-30 cm, and nonwoven fabric conveying speed 1-5 m / min.

[0020] A second aspect of the present invention provides a nonwoven fabric with silver / plant essential oil synergistic antibacterial properties prepared by the above method.

[0021] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. This invention combines the antibacterial properties of inorganic silver with the antibacterial properties of natural plant essential oils. The modified silver-containing short fibers provide a long-lasting and broad-spectrum antibacterial basis, while specific components in the compound essential oils can effectively destroy the cell membranes of microorganisms, significantly promote the penetration and action of silver ions, and produce a synergistic antibacterial effect. This results in a stronger ability to cope with complex microbial environments and excellent water resistance.

[0022] 2. By encapsulating and protecting the volatile compound essential oils using microencapsulation technology, the slow and controlled release of the essential oils is achieved, greatly extending the duration of the soothing and antibacterial efficacy of the nonwoven fabric product. Simultaneously, modified silver-containing short fibers firmly anchor the silver particles through chemical bonding, preventing rapid loss during use and ensuring the long-term stability of the antibacterial effect.

[0023] 3. The electrostatic spraying process enables microcapsules to be evenly distributed and fixed on the fiber surface and shallow layer in a single layer, avoiding the problems of pore blockage and hardening caused by excessive finishing liquid in traditional padding or coating methods, and preserving the original softness, fluffiness and high air permeability of nonwoven fabric to the greatest extent. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, all raw materials used in the embodiments are commercially available products. The following sources are illustrative examples.

[0026] Spike lavender essential oil was purchased from Yili Tianyao Biotechnology Co., Ltd.; kava pepper essential oil was purchased from Naissance Natural Products; tea tree essential oil was purchased from Guangzhou Anu Biotechnology Co., Ltd.; and chamomile essential oil was purchased from Guangzhou Jiamile Cosmetics Co., Ltd.

[0027] Example 1 This embodiment provides a nonwoven fabric with synergistic antibacterial properties of silver and plant essential oil, the preparation method of which includes the following steps: (1) Preparation of modified silver-containing short fibers: (i) Take polypropylene (PP) short fibers with a fineness of 2.2D and a length of 40mm as the matrix, place them in a chitosan-acetic acid aqueous solution with a mass concentration of 10% (using acetic acid aqueous solution with a mass fraction of 1% as solvent and chitosan solution with a mass concentration of 10%), and immerse them at 70°C for 45 minutes.

[0028] (ii) Remove the fiber and immerse it in a 0.3 mol / L silver nitrate solution. Under ultrasonic oscillation with a power of 200W, slowly add a 0.15 mol / L ascorbic acid solution, controlling the molar ratio of ascorbic acid to silver nitrate to be 1.1:1, and react at 60℃ for 2 hours.

[0029] (iii) After the reaction is complete, the fiber is washed with deionized water until neutral and dried at 80°C to obtain modified silver-containing short fiber.

[0030] 70% polypropylene (PP) fiber (2.2D, 40mm) and 30% polyethylene / polypropylene composite (ES) fiber (3.0D, 51mm) were mixed as the main fiber, and modified silver-containing short fibers (3% of the total mass) were added. The above mixed fibers were opened by an opening machine, and after being mixed evenly in a blending box, they were carded by a carding machine to a basis weight of 25 g / m². 2 The fiber web was then placed in a hot air oven and cured with hot air for 2 minutes at 140°C and a wind speed of 1.2 m / s to obtain a silver-containing base nonwoven fabric.

[0031] (2) Preparation of compound essential oil microcapsule finishing solution: (a) Accurately weigh lavender essential oil, kava essential oil, tea tree essential oil, and chamomile essential oil in a mass ratio of 3.5:1:2:1, mix them evenly as the core material, and use gelatin, gum arabic, and sodium alginate (mass ratio of 1:1:0.2) as the composite wall material. Control the mass ratio of core material to wall material to be 1:2, and use the complex coagulation method for encapsulation: first, prepare a 4% aqueous solution of gelatin at 55°C, and prepare a 4% mixed solution of gum arabic and sodium alginate at 50°C; add the compound essential oils to the mixed solution, and emulsify at high speed at 10000 rpm for 5 minutes to form a primary emulsion; then, at 500... The gelatin solution was slowly poured into the emulsion under stirring at rpm, and after mixing, the mixture was cooled to 40°C to initiate a coagulation reaction. Then, the pH of the system was adjusted to 4.2 with 10% acetic acid solution for acidification and curing, and stirring was continued for 30 minutes. The system was then cooled to 10°C, and 0.5% of glutaraldehyde solution by weight of the wall material was added for cross-linking for 1 hour to fix the microcapsule wall. Finally, the mixture was filtered, washed with water until neutral, and vacuum dried at 45°C for 6 hours to obtain the compound essential oil microcapsules.

[0032] (b) The compound essential oil microcapsules were dispersed in deionized water to prepare a dispersion system with a solid content of 20%. Then, an aqueous polyurethane dispersion was added as a binder, with a solid addition amount of 10% of the mass of the microcapsules, and a penetrant JFC accounting for 0.3% of the total mass of the finishing solution. The mixture was mechanically stirred for 30 minutes to obtain the compound essential oil microcapsule finishing solution.

[0033] The compound essential oil microcapsule finishing solution was injected into an electrostatic spraying device. The process parameters were set as follows: voltage 50 kV, finishing solution flow rate 12 mL / min, distance between the nozzle and the nonwoven fabric substrate 20 cm, and nonwoven fabric conveying speed 3 m / min. Under the action of an electrostatic field, the microcapsule finishing solution was uniformly sprayed onto the surface of the silver-containing base nonwoven fabric.

[0034] (3) The nonwoven fabric after spraying is placed in an oven at 70°C and dried for 10 minutes to allow the adhesive to fully form a film and fix the microcapsules, and finally the nonwoven fabric product with silver / plant essential oil synergistic antibacterial effect is obtained.

[0035] Example 2 This embodiment provides a nonwoven fabric with synergistic antibacterial properties of silver and plant essential oils. The difference from Embodiment 1 is that the preparation method of the modified silver-containing short fibers is as follows: (i) Take polyethylene (PE) short fibers with a fineness of 3.0D and a length of 50mm as the matrix, place them in a chitosan-acetic acid aqueous solution with a mass concentration of 7% (using acetic acid aqueous solution with a mass fraction of 1% as the solvent and chitosan solution with a mass concentration of 7%), and immerse them at 70°C for 55 minutes.

[0036] (ii) Remove the fiber and immerse it in a 0.2 mol / L silver nitrate solution. Under ultrasonic oscillation with a power of 200W, slowly add a 0.15 mol / L ascorbic acid solution, controlling the molar ratio of ascorbic acid to silver nitrate to be 1:1, and react at 50℃ for 3 hours.

[0037] (iii) After the reaction is complete, the fiber is washed with deionized water until neutral and dried at 80°C to obtain modified silver-containing short fiber.

[0038] Everything else is the same as in Example 1.

[0039] Example 3 This embodiment provides a nonwoven fabric with silver / plant essential oil synergistic antibacterial properties. The difference from embodiment 1 is that the mass ratio of spike lavender essential oil, kava pepper essential oil, tea tree essential oil and chamomile essential oil in step (2) is 3:1:2.5:0.9.

[0040] Everything else is the same as in Example 1.

[0041] Comparative Example 1 The difference between this comparative example and Example 1 is that the preparation method of the modified silver-containing short fiber is replaced with: (i) Take polypropylene (PP) short fibers (2.2D, 40mm) as the matrix, immerse them in 0.3 mol / L silver nitrate solution, and soak them at 60°C for 45 minutes to allow silver ions to be adsorbed on the fiber surface.

[0042] (ii) Remove the fiber, drain off the excess solution, and immerse it in a 0.15 mol / L ascorbic acid solution (controlling the molar ratio with silver nitrate to be approximately 1.1:1), and let it stand at 60°C for 2 hours for reduction.

[0043] (iii) After the reaction is complete, the fiber is washed with deionized water until neutral and dried at 80°C to obtain modified silver-containing short fiber.

[0044] Comparative Example 2 The difference between this comparative example and Example 1 is that the modified silver-containing short fibers are replaced with silver-containing short fibers prepared by the following method: (i) Silver-loaded zirconium phosphate antibacterial agent (silver content is 3.5% of the total antibacterial agent mass) is premixed with polypropylene (PP) chips at a mass ratio of 3:97, and then melt-blended and granulated by a twin-screw extruder to obtain silver-containing antibacterial masterbatch; (ii) The above-mentioned silver-containing antibacterial masterbatch and pure polypropylene chips are mixed again at a mass ratio of 1:4, and spun by melt spinning equipment. After stretching, silver-containing short fibers with a fineness of 2.2D and a length of 40mm are obtained.

[0045] Comparative Example 3 The difference between this comparative example and Example 1 is that the compound essential oils were replaced with spike lavender essential oil, tea tree essential oil and chamomile essential oil in a mass ratio of 3.5:2:1, i.e., without kava pepper essential oil.

[0046] Comparative Example 4 The difference between this comparative example and Example 1 is that the compound essential oils were replaced with lavender essential oil, kava pepper essential oil, tea tree essential oil and chamomile essential oil in a mass ratio of 3.5:1:2:1.

[0047] Comparative Example 5 The difference between this comparative example and Example 1 is as follows: After preparing the compound essential oil microcapsule finishing solution in step (2), the silver-containing base nonwoven fabric is immersed in the finishing solution and a two-dip two-ply process is adopted to control the ply rate to 80%. Subsequently, the ply-ply nonwoven fabric is post-treated under the same conditions as Example 1 (drying at 70°C for 10 minutes) to obtain the nonwoven fabric of Comparative Example 5.

[0048] Performance testing Test samples: Nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-5.

[0049] Test method: 1. Antibacterial rate: Referring to the national standard GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method", the antibacterial rates of the samples against Staphylococcus aureus (Gram-positive bacteria) and Escherichia coli (Gram-negative bacteria) were tested. The test consisted of initial antibacterial rate and antibacterial rate after 10 washes to examine the immediacy and durability of the antibacterial effect.

[0050] 2. Durability of Essential Oil Release: Thermogravimetric analysis (TGA) was used for testing. 5.0 mg of sample was accurately weighed and heated from 30°C to 300°C at a rate of 10°C / min under a nitrogen atmosphere. The initial essential oil content (W0) was defined as the percentage of mass loss of the sample within the temperature range of 50°C to 250°C. After accelerated aging in a 40°C constant-temperature drying oven for 60 days, TGA testing was performed again to obtain the essential oil content after aging (W1). The essential oil residue rate (%) was calculated using the following formula: Essential oil residue rate = (W1 / W0) × 100%.

[0051] 3. Air permeability: Refer to standard GB / T 5453 and use a fabric air permeability meter to measure the air permeability (mm / s) of the nonwoven fabric.

[0052] 4. Silver element fastness: After washing the sample with water 10 times, collect all the washing liquid and use inductively coupled plasma optical emission spectrometry (ICP-OES) to determine the silver element content in the washing liquid and calculate the silver loss rate, thereby characterizing the bonding strength between the silver component and the fiber.

[0053] The test results are shown in Table 1.

[0054] Table 1 Performance Test Results

[0055] The test results above show that the nonwoven fabric products prepared in Examples 1-3 all exhibit excellent performance in terms of high efficiency, durability and balance.

[0056] Comparative Example 1: The silver-containing short fibers were not pretreated with chitosan, resulting in weak bonding between silver particles and fibers. A large amount of silver was shed during washing, severely weakening the product's durable antibacterial properties. Comparative Example 2: Silver-containing fibers were prepared using a blend spinning method. The silver component was encapsulated within the fibers, making it difficult to quickly migrate to the surface and exert its effect. This resulted in significantly low initial antibacterial efficiency, failing to meet the need for immediate antibacterial action. Comparative Example 3: The absence of the crucial kava pepper oil in the compound essential oil weakened the synergistic antibacterial pathway between the essential oil system and silver ions, leading to a noticeable decrease in both antibacterial durability and sustained-release properties. Comparative Example 4: Lavender essential oil was used instead of spike lavender essential oil. Due to the difference in the content and composition of key active ingredients, the overall synergistic antibacterial efficacy and the stability of the essential oil system decreased, with all performance indicators inferior to Example 1. Comparative Example 5 uses a traditional padding process, which results in the destruction of a large number of microcapsules and premature loss of essential oils due to the high mechanical extrusion. At the same time, the high liquid carryover rate causes blockage of the nonwoven fabric pores, which seriously degrades the product's long-lasting effect and breathability.

[0057] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a silver / plant essential oil synergistic antibacterial non-woven fabric, comprising the following steps: (1) mixing the main fibers with the modified silver-containing short fibers, carding into a web with a grammage of 20-45 g / m 2 , and then hot air reinforcing the web to obtain a silver-containing base nonwoven fabric; (2) preparing a compound essential oil microcapsule finishing liquid, and electrostatically spraying the finishing liquid onto the silver-containing base non-woven fabric of step (1); the compound essential oil comprises lavender essential oil, kava pepper essential oil, tea tree essential oil and chamomile essential oil; (3) drying the non-woven fabric electrostatically sprayed in step (2) to obtain the silver / plant essential oil synergistic antibacterial non-woven fabric.

2. The production method according to claim 1, characterized by, In step (1), the main fibers are one or both of polyethylene / polypropylene composite fibers and polypropylene fibers.

3. The preparation method according to claim 1, characterized in that, In step (1), the modified silver-containing short fibers are prepared as follows: (i) taking polyethylene or polypropylene short fibers as a substrate, and immersing the substrate in a chitosan-acetic acid aqueous solution with a mass concentration of 5-15% at 60-80°C for 30-60 minutes; (ii) taking out the immersed fibers, immersing them in a silver nitrate solution with a concentration of 0.1-0.5 mol / L, and adding a reducing agent ascorbic acid dropwise under ultrasonic oscillation, with the molar ratio of ascorbic acid to silver nitrate controlled at (1-1.2):1, and reacting at 50-70°C for 1-3 hours; (iii) after the reaction, washing the fibers to neutral, and drying to obtain the modified silver-containing short fibers.

4. The preparation method according to claim 3, characterized in that, In step (i), the polyethylene or polypropylene short fibers have a fineness of 1.5-3.5D and a length of 30-60 mm.

5. The preparation method according to claim 1, characterized in that, In step (1), the mass of the modified silver-containing short fibers accounts for 1-10% of the total mass of the fibers.

6. The method of claim 1, wherein, In step (1), the temperature of the hot air reinforcement is 120-160°C, the air speed is 0.5-2.0 m / s, and the time of the hot air reinforcement is 1-3 minutes.

7. The preparation method according to claim 1, characterized in that, In step (2), the mass ratio of the lavender essential oil, kava pepper essential oil, tea tree essential oil and chamomile essential oil is (3.0-4.0):(1.5-2.5):(0.8-1.2).

8. The method of claim 1, wherein, In step (2), the compound essential oil microcapsule finishing liquid is prepared as follows: (a) mixing the lavender essential oil, kava pepper essential oil, tea tree essential oil and chamomile essential oil as core material, taking a composite system of gelatin, gum arabic and sodium alginate as wall material, and using the complex coacervation method to coat, with the mass ratio of the core material to the wall material controlled at 1:(1-4) to prepare the compound essential oil microcapsules; (b) dispersing the compound essential oil microcapsules in deionized water, adding water-based polyurethane dispersion as adhesive and penetrant JFC, and stirring to obtain the compound essential oil microcapsule finishing liquid.

9. The preparation method according to claim 8, characterized in that, In step (a), the mass ratio of gelatin, gum arabic and sodium alginate is 1:(0.8-1.2):(0.1-0.3); in step (b), the amount of water-based polyurethane dispersion is 5%-15% of the mass of the microcapsules, and the amount of penetrant JFC is 0.1%-0.5% of the total mass of the finishing liquid.

10. A nonwoven fabric having synergistic antibacterial effect of silver and a plant essential oil, characterized by comprising a plant essential oil and silver. The method is prepared according to any one of claims 1-9.

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