Antibacterial silk and preparation method thereof

Abstract

The invention relates to the technical field of textile materials, and discloses antibacterial silk and a preparation method thereof.The antibacterial silk is prepared by dipping acetylation-modified degummed mulberry silk in composite antibacterial liquid and conducting thermocuring, and the composite antibacterial liquid comprises nano-silver colloid, a copper sulfate-chitosan complex, natural plant extract and a cross-linking agent; the composite antibacterial liquid takes a mixed solvent of ethanol and water as a carrier. Wherein the acetylation modification is realized by the following steps: immersing the degummed mulberry silk into a DMF (Dimethyl Formamide) solution containing 5-10wt% of acetic acid acetyl tert-butyl ester, reacting at 80-150 DEG C for 1-6 hours, and grafting an acetoacetic acid group. The nano-material, the metal complex and the natural antibacterial component are compositely loaded on the surface of the silk fiber in a chemical bonding and physical adsorption combined mode, efficient, broad-spectrum and durable antibacterial performance is achieved, and the silk fiber is suitable for the high-added-value fields of medical treatment, clothes and the like.

Description

Technical Field

[0001] The invention relates to the technical field of textile materials, in particular to antibacterial silk and a preparation method thereof. Background Art

[0002] Silk, as a natural protein fiber, has good moisture absorption and breathability, but it is susceptible to bacterial and mold growth, leading to fiber degradation and odor. Existing antimicrobial technologies are primarily categorized into two types: inorganic or organic antimicrobial finishing and chemically modified grafted antimicrobial groups. Inorganic or organic antimicrobial finishing involves fixing the fiber surface with agents such as nanosilver and copper sulfate through impregnation or coating, but these methods suffer from particle detachment and poor washability. Chemically modified grafted antimicrobial groups, such as acetylation combined with amino antimicrobials, are complex processes and have a limited antimicrobial spectrum.

[0003] Therefore, there is an urgent need to develop a composite process that combines chemical bonding with natural antibacterial ingredients to solve the problems of uneven dispersion of antibacterial agents and insufficient wash resistance. Summary of the Invention

[0004] In view of this, in order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide an antibacterial silk and a preparation method thereof, which combines chemical bonding with physical adsorption to load nanomaterials, metal complexes and natural antibacterial components on the surface of silk fibers to achieve high-efficiency, broad-spectrum and durable antibacterial properties, and is suitable for high-value-added fields such as medical care and clothing.

[0005] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides an antibacterial silk, which is prepared by impregnating acetylated degummed mulberry silk with a composite antibacterial liquid and heat-curing. The composite antibacterial liquid contains nanosilver colloid, copper sulfate-chitosan complex, natural plant extracts and a cross-linking agent.

[0006] As a further embodiment of the present invention, the composite antibacterial solution comprises the following components: Nanosilver colloid, particle size 20-50nm, concentration 0.01-0.1wt%; Copper sulfate-chitosan complex, the molar ratio of chitosan to copper sulfate is 1:0.5-1.5; Natural plant extracts, selected from at least two of baicalein, honeysuckle polyphenols or mugwort extract, with a mass ratio of 1:1-3 and a total concentration of 0.5-2wt%; The cross-linking agent is glutaraldehyde or polyethylene glycol diglycidyl ether, with a concentration of 0.1-1wt%.

[0007] As a further solution of the present invention, the composite antibacterial liquid uses a mixed solvent of ethanol and water as a carrier, and the volume ratio of ethanol to water is 1:3-5.

[0008] As a further embodiment of the present invention, the acetylation modification is achieved by the following steps: immersing the degummed mulberry silk in a DMF solution containing 5-10 wt% tert-butyl acetate, reacting at 80-150° C. for 1-6 hours, and grafting acetoacetate groups.

[0009] As a further embodiment of the present invention, the acetylation modification further comprises pretreatment of the silk substrate: immersing the degummed mulberry silk in a 1-3 wt% sodium carbonate solution at 80-100° C. for 20-40 minutes, removing residual sericin, and then washing to a neutral state.

[0010] In a second aspect, the present invention further provides a method for preparing antibacterial silk, comprising the following steps: a. Silk pretreatment: Immerse the degummed mulberry silk in a 1-3wt% sodium carbonate solution at 80-100°C for 20-40 minutes and rinse until neutral; b. Acetylation modification: The pretreated silk is immersed in a DMF solution containing 5-10wt% tert-butyl acetate, reacted at 80-150°C for 1-6 hours, and then washed and dried; c. Composite antibacterial liquid impregnation: immerse the modified silk in the composite antibacterial liquid at 40-60°C and ultrasonic frequency of 20-50kHz for 2-6 hours; d. Curing and post-treatment: rolling (liquid content 60-90%), pre-baking at 80-100℃ for 10-30 minutes, heat curing at 120-160℃ for 20-60 minutes, and washing with water to remove unbound components.

[0011] As a further embodiment of the present invention, the concentration of each component in the composite antibacterial solution is: Nano silver colloid 0.01-0.1wt%, copper sulfate-chitosan complex 0.5-3wt%, plant extract 0.5-2wt%, cross-linking agent 0.1-1wt%.

[0012] As a further solution of the present invention, a composite antibacterial layer with a thickness of 50-200 nm is formed on the fiber surface of the antibacterial silk. The composite antibacterial layer is composed of nanosilver particles and plant extracts, and its tensile strength is increased by 10-20% compared with untreated silk.

[0013] As a further embodiment of the present invention, the molecular weight of chitosan in the copper sulfate-chitosan complex is 10-50 kDa, and the degree of deacetylation is ≥85%.

[0014] As a further embodiment of the present invention, the volume ratio of ethanol to water in the solvent of the composite antibacterial liquid is 1:4, and the ultrasonic frequency in the immersion process is 30 kHz.

[0015] Compared with the existing technology, the present invention provides an antibacterial silk and its preparation method. By loading nanomaterials, metal complexes and natural antibacterial components onto the surface of silk fibers, the antibacterial silk achieves high-efficiency, broad-spectrum and durable antibacterial properties, with the following beneficial effects: 1. Highly effective antibacterial properties. This antibacterial silk uses nanosilver colloids with a particle size of 20-50nm, which have a large specific surface area and excellent antibacterial activity, effectively inhibiting the growth of a variety of bacteria and fungi. The chitosan in the copper sulfate-chitosan complex itself has good biocompatibility and antibacterial properties, and the complexation with copper sulfate further enhances the antibacterial effect. Natural plant extracts such as baicalein, honeysuckle polyphenols, and mugwort extract have natural antibacterial properties. When used in combination, they can provide a broad-spectrum antibacterial effect.

[0016] 2. Through a combination of chemical bonding and physical adsorption, the antibacterial ingredients are more firmly attached to the silk surface, improving the durability of the antibacterial effect. Through heat curing treatment, the antibacterial layer is further stabilized, ensuring that the antibacterial performance remains effective after multiple washes. A composite antibacterial layer is formed on the surface of the treated antibacterial silk fiber, which increases the tensile strength compared to untreated silk, while maintaining the soft feel of silk and improving its mechanical properties. After acetylation modification and composite antibacterial treatment, the stability and softness of the silk fiber are effectively maintained and improved.

[0017] 3. In the antibacterial silk of the present invention, the natural plant extracts in the composite antibacterial liquid are derived from nature, are safe and non-toxic, and meet environmental protection and health standards. Ethanol and water are used as solvents, which reduces the use of organic solvents. The process is environmentally friendly and environmentally friendly. Due to its excellent antibacterial properties and biocompatibility, the antibacterial silk of the present invention is suitable for medical textiles such as wound dressings, medical gauze, etc. The antibacterial silk is also suitable for high-value-added clothing products, providing long-term and effective antibacterial and deodorizing functions, and improving wearing comfort and safety.

[0018] In summary, the antibacterial silk and its preparation method provided by the present invention, through innovative composite antibacterial technology, not only significantly improve the antibacterial properties and durability of silk, but also enhance the mechanical properties and safety of fiber, and have broad application prospects and market value. DETAILED DESCRIPTION

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the specification.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0022] Example 1 The first embodiment of the present invention provides an antibacterial silk, and the specific preparation steps of the antibacterial silk are as follows: 1. Raw materials and components.

[0023] (1) Silk substrate: degummed mulberry silk fabric (pretreated with sodium carbonate solution).

[0024] (2) Compound antibacterial liquid formula: Nanosilver colloid: particle size 30nm, concentration 0.05wt%; Copper sulfate-chitosan complex: chitosan (molecular weight 30 kDa, deacetylation degree ≥90%) and copper sulfate in a molar ratio of 1:1; Natural plant extracts: baicalein and honeysuckle polyphenols (mass ratio 1:1), total concentration 1wt%; Cross-linking agent: glutaraldehyde, concentration 0.5wt%; Solvent: a mixed solution of ethanol and water (volume ratio 1:4).

[0025] 2. Preparation steps.

[0026] Step 1: Silk pre-treatment: The degummed mulberry silk was immersed in a 2 wt % sodium carbonate solution at 90 °C for 30 min to remove residual sericin, and then washed with deionized water until neutral.

[0027] Step 2: Acetylation modification: The pretreated silk was immersed in a DMF solution containing 8 wt% tert-butyl acetate (bath ratio 1:10) and reacted at 100°C for 2 hours to graft acetoacetate groups. After the reaction, the silk was rinsed three times with ethanol and dried.

[0028] Step 3: Impregnation with composite antibacterial liquid.

[0029] Preparation of antibacterial solution: dissolve nanosilver colloid, copper sulfate-chitosan complex, plant extract and cross-linking agent in ethanol / water mixed solvent according to the above formula.

[0030] Ultrasonic-assisted impregnation: The modified silk was immersed in the antibacterial solution and immersed under 50°C, 30kHz ultrasonic conditions for 4 hours to ensure that the antibacterial agent fully penetrated the interior of the fiber.

[0031] Step 4: Curing and post-processing.

[0032] Rolling: liquid rate is controlled at 80%; Pre-baking: 90℃ for 20 minutes; Thermal curing: 140℃ for 30 minutes; Washing: Wash with deionized water to remove unbound components, and dry at room temperature to produce antibacterial silk.

[0033] The antibacterial properties of the antibacterial silk prepared in this example were tested, and the initial antibacterial rates against Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) were ≥99.5%. After 50 washes according to the GB / T 3921-2008 standard, the antibacterial rates remained ≥95%.

[0034] The mechanical properties of the antibacterial silk prepared in this example were tested, wherein a composite antibacterial layer with a thickness of about 120 nm was formed on the fiber surface; and the tensile strength was increased by 15% compared with that of the untreated silk.

[0035] The antibacterial silk prepared in this example contains ≥30% plant extracts, and the ethanol / water solvent system reduces organic solvent usage, making it environmentally friendly. It utilizes a synergistic antibacterial mechanism: nanosilver (contact sterilization) and copper sulfate-chitosan (sustained copper ion release) work synergistically, combined with plant extracts to disrupt bacterial membrane structures, acetylation modification covalently binds the antibacterial agent, and ultrasonic impregnation improves dispersion uniformity. Experimental verification demonstrates that the silk meets antibacterial performance and washability requirements, making it suitable for medical dressings and high-end apparel.

[0036] Example 2 The second embodiment of the present invention provides an antibacterial silk, and the specific preparation steps of the antibacterial silk are as follows: 1. Raw materials and components.

[0037] (1) Silk substrate: degummed mulberry silk fabric (pretreated with sodium carbonate solution).

[0038] (2) Compound antibacterial liquid formula: Nanosilver colloid: particle size 40nm, concentration 0.08wt%; Copper sulfate-chitosan complex: chitosan (molecular weight 20 kDa, deacetylation degree ≥88%): copper sulfate molar ratio 1:1.2; Natural plant extracts: baicalein and mugwort extract (mass ratio 1:2), total concentration 1.5wt%; Cross-linking agent: polyethylene glycol diglycidyl ether, concentration 0.8wt%; Solvent: a mixed solution of ethanol and water (volume ratio 1:3).

[0039] 2. Preparation steps.

[0040] Step 1: Silk pre-treatment: The degummed mulberry silk was immersed in a 3 wt % sodium carbonate solution at 100 °C for 40 min to remove residual sericin, and then washed with deionized water until neutral.

[0041] Step 2: Acetylation modification: The pretreated silk was immersed in a DMF solution containing 10 wt% tert-butyl acetate (bath ratio 1:15) and reacted at 150°C for 3 hours to graft acetoacetate groups. After the reaction, the silk was rinsed three times with ethanol and dried.

[0042] Step 3: Compound antibacterial liquid impregnation: Preparation of antibacterial liquid: Dissolve nanosilver colloid, copper sulfate-chitosan complex, plant extract and cross-linking agent in ethanol / water mixed solvent according to the above formula.

[0043] Ultrasonic-assisted impregnation: The modified silk was immersed in the antibacterial solution and immersed under 60°C, 40kHz ultrasonic conditions for 5 hours to ensure that the antibacterial agent penetrated deep into the fiber.

[0044] Step 4: Curing and post-processing: Rolling: Liquid rate is controlled at 90%; Pre-baking: 100℃ for 25 minutes; Thermal curing: 155℃ for 45 minutes; Washing: Wash with deionized water to remove unbound components, and dry at room temperature to produce antibacterial silk.

[0045] The antibacterial performance of the antibacterial silk prepared in this example was tested, and the initial antibacterial rate against Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) was ≥99.8%. After 50 washes according to the GB / T 3921-2008 standard, the antibacterial rate was still ≥96%.

[0046] The mechanical properties of the antibacterial silk prepared in this example were tested, and a composite antibacterial layer with a thickness of about 150 nm was formed on the fiber surface; the tensile strength was increased by 18% compared with that of the untreated silk.

[0047] The antibacterial silk prepared in this example contains ≥35% plant extracts. The ethanol / water solvent system reduces the amount of organic solvents used, meeting OEKO-TEX® standards. The antibacterial silk prepared in this example exhibits a synergistic effect with a composite antimicrobial agent: nanosilver (particle size 40 nm) destroys bacterial cell membranes through contact sterilization; the copper sulfate-chitosan complex slowly releases copper ions, inhibiting bacterial metabolism; and baicalein and mugwort extract (mass ratio 1:2) enhance the antibacterial spectrum through polyphenol oxidation.

[0048] In this example, the antimicrobial silk fabric was prepared using high-temperature, short-term acetylation (150°C for 3 hours) to increase the acetyl group density on the fiber surface. High-concentration ultrasonic impregnation (40kHz) promoted uniform penetration of the antimicrobial agent into the fiber. Polyethylene glycol diglycidyl ether crosslinker formed a three-dimensional network structure, enhancing the binding of the antimicrobial agent. A chitosan deacetylation degree of ≥88% ensured complex stability and prevented excessive copper ion release. By adjusting the component ratios and process parameters of the composite antimicrobial solution, this example demonstrated the flexibility and universality of the technical solution, demonstrating its applicability to medical dressings and high-end antimicrobial apparel.

[0049] Example 3 The third embodiment of the present invention provides an antibacterial silk. The specific preparation steps of the antibacterial silk are as follows: 1. Raw materials and components.

[0050] (1) Silk substrate: degummed mulberry silk fabric (pretreated with sodium carbonate solution).

[0051] (2) Compound antibacterial liquid formula: Nanosilver colloid: particle size 25nm, concentration 0.03wt%; Copper sulfate-chitosan complex: chitosan (molecular weight 40 kDa, deacetylation degree ≥90%): copper sulfate molar ratio 1:0.8; Natural plant extracts: baicalein and honeysuckle polyphenols (mass ratio 1:2), total concentration 1.2wt%; Cross-linking agent: polyethylene glycol diglycidyl ether, concentration 0.3wt%; Solvent: a mixed solution of ethanol and water (volume ratio 1:5).

[0052] 2. Preparation steps.

[0053] Step 1: Silk pre-treatment: The degummed mulberry silk was immersed in 2.5 wt% sodium carbonate solution and treated at 85 °C for 35 min to remove residual sericin, and then washed with deionized water until neutral.

[0054] Step 2: Acetylation modification: The pretreated silk was immersed in a DMF solution containing 7 wt% tert-butyl acetate (bath ratio 1:12) and reacted at 130°C for 4 hours to graft acetoacetate groups. After the reaction, the silk was rinsed three times with ethanol and dried.

[0055] Step 3: Compound antibacterial liquid impregnation: Preparation of antibacterial liquid: Dissolve nanosilver colloid, copper sulfate-chitosan complex, plant extract and cross-linking agent in ethanol / water mixed solvent according to the above formula.

[0056] Ultrasonic-assisted impregnation: The modified silk was immersed in the antibacterial solution and immersed under 55°C, 25kHz ultrasonic conditions for 5 hours to ensure that the antibacterial agent penetrated deep into the fiber.

[0057] Step 4: Curing and post-processing: Rolling: Liquid rate is controlled at 85%; Pre-baking: 95℃ for 25 minutes; Thermal curing: 150℃ for 40 minutes; Water washing: Wash with deionized water to remove unbound components and dry at room temperature.

[0058] The antibacterial properties of the antibacterial silk prepared in this example were tested, and the initial antibacterial rates against Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 6538) were ≥99.7%. After 50 washes according to the GB / T 3921-2008 standard, the antibacterial rates were still ≥96%.

[0059] The mechanical properties of the antibacterial silk prepared in this example were tested. A composite antibacterial layer with a thickness of about 180 nm was formed on the fiber surface; and the tensile strength was increased by 17% compared with that of the untreated silk.

[0060] The antibacterial silk prepared in this example contains ≥32% plant extracts. The ethanol / water solvent system reduces the amount of organic solvents used, meeting OEKO-TEX® standards. In this example, nanosilver (25 nm) destroys bacterial cell membranes through contact sterilization; a copper sulfate-chitosan complex (chitosan deacetylation ≥90%) slowly releases copper ions, inhibiting bacterial metabolism; and baicalein and honeysuckle polyphenols (mass ratio 1:2) enhance the antibacterial spectrum through polyphenol oxidation. During the preparation process, a moderate-temperature, long-term acetylation modification (130°C for 4 hours) balances the acetyl group density on the fiber surface with energy consumption. Low-frequency ultrasonic impregnation (25 kHz) enhances the penetration efficiency of the antimicrobial agent and prevents fiber damage. Polyethylene glycol diglycidyl ether crosslinker forms a flexible crosslinked network, enhancing the binding strength of the antimicrobial agent. The nanosilver and plant extract composite layer (180 nm) provides a dual antimicrobial barrier. The antibacterial silk prepared in this example is suitable for medical dressings and high-end home textiles.

[0061] It is important to note that the construction and arrangement of the present application, as illustrated in various exemplary embodiments, are illustrative only. Although only a few embodiments are described in detail in this disclosure, those reading this disclosure will readily appreciate that numerous modifications are possible (e.g., variations in the size, dimensions, structure, shape, and proportions of various components, as well as parameter values (e.g., temperature, pressure, etc.), mounting arrangements, use of materials, color, orientation, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. For example, components shown as integrally formed may be constructed from multiple parts or components, the positions of components may be inverted or otherwise altered, and the nature, number, or position of discrete components may be modified or changed. All such modifications are therefore intended to be encompassed within the scope of this invention. The order or sequence of any process or method steps may be altered or resequenced according to alternative embodiments. In the claims, any "means-plus-function" clause is intended to cover structures described herein that perform the recited function, and not only structural equivalents but also equivalent structures. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the exemplary embodiments without departing from the scope of this invention. Therefore, the invention is not limited to the specific embodiments, but extends to various modifications that still fall within the scope of the appended claims.

[0062] Additionally, in order to provide a concise description of exemplary embodiments, all features of an actual embodiment may not be described (i.e., those features that are not relevant to the best mode presently contemplated for carrying out the invention or those that are not relevant to implementing the invention).

[0063] It will be appreciated that in the development of any actual embodiment, as in any engineering or design project, numerous implementation-specific decisions may be made. Such a development effort may be complex and time-consuming, but will, for those of ordinary skill having the benefit of this disclosure, be a routine undertaking of design, fabrication, and production without undue experimentation.

[0064] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An antibacterial silk, characterized in that: The invention is prepared by impregnating acetylated degummed mulberry silk with a composite antibacterial liquid and heat-curing the composite antibacterial liquid, wherein the composite antibacterial liquid contains nano silver colloid, copper sulfate-chitosan complex, natural plant extract and cross-linking agent.

2. The antibacterial silk according to claim 1, characterized in that: The composite antibacterial solution comprises the following components: Nanosilver colloid, particle size 20-50nm, concentration 0.01-0.1wt%; Copper sulfate-chitosan complex, the molar ratio of chitosan to copper sulfate is 1:0.5-1.5; Natural plant extracts, selected from at least two of baicalein, honeysuckle polyphenols or mugwort extract, with a mass ratio of 1:1-3 and a total concentration of 0.5-2wt%; The cross-linking agent is glutaraldehyde or polyethylene glycol diglycidyl ether, with a concentration of 0.1-1wt%.

3. The antibacterial silk according to claim 2, characterized in that: The composite antibacterial liquid uses a mixed solvent of ethanol and water as a carrier, and the volume ratio of ethanol to water is 1:3-5.

4. The antibacterial silk according to claim 1, characterized in that: The acetylation modification is achieved by the following steps: immersing the degummed mulberry silk in a DMF solution containing 5-10 wt% of tert-butyl acetate, reacting at 80-150° C. for 1-6 hours, and grafting acetoacetate groups.

5. The antibacterial silk according to claim 4, characterized in that: The acetylation modification further includes pretreatment of the silk substrate: immersing the degummed mulberry silk in a 1-3 wt% sodium carbonate solution at 80-100° C. for 20-40 minutes, removing residual sericin, and then washing to a neutral state.

6. A method for preparing the antibacterial silk according to any one of claims 1 to 5, characterized in that: The preparation method comprises the following steps: a. Silk pretreatment: Immerse the degummed mulberry silk in a 1-3wt% sodium carbonate solution at 80-100°C for 20-40 minutes and rinse until neutral; b. Acetylation modification: The pretreated silk is immersed in a DMF solution containing 5-10wt% tert-butyl acetate, reacted at 80-150°C for 1-6 hours, and then washed and dried; c. Composite antibacterial liquid impregnation: immerse the modified silk in the composite antibacterial liquid at 40-60°C and ultrasonic frequency of 20-50kHz for 2-6 hours; d. Curing and post-treatment: rolling, pre-baking at 80-100℃ for 10-30 minutes, heat curing at 120-160℃ for 20-60 minutes, and washing with water to remove unbound components.

7. The method for preparing antibacterial silk according to claim 6, characterized in that: The concentration of each component in the composite antibacterial solution is: Nano silver colloid 0.01-0.1wt%, copper sulfate-chitosan complex 0.5-3wt%, plant extract 0.5-2wt%, cross-linking agent 0.1-1wt%.

8. The method for preparing antibacterial silk according to claim 7, characterized in that: A composite antibacterial layer with a thickness of 50-200 nm is formed on the fiber surface of the antibacterial silk. The composite antibacterial layer is composed of nano-silver particles and plant extracts, and its tensile strength is increased by 10-20% compared with that of untreated silk.

9. The method for preparing antibacterial silk according to claim 8, characterized in that: The molecular weight of chitosan in the copper sulfate-chitosan complex is 10-50 kDa, and the degree of deacetylation is ≥85%.

10. The method for preparing antibacterial silk according to claim 9, characterized in that: The volume ratio of ethanol to water in the solvent of the composite antibacterial liquid is 1:4, and the ultrasonic frequency in the immersion process is 30 kHz.