Intrinsic flame-retardant, high-strength aramid protective fabric and preparation method thereof

Abstract

The application discloses an intrinsic flame-retardant high-strength aramid protective fabric and a preparation method thereof, and belongs to the technical field of protective fabrics. The aramid protective fabric comprises a first thin layer and a second thin layer, and the second thin layer is loaded on the outer surface of the first thin layer. The first thin layer is a single-layer fabric structure, the outer layer region and the inner layer region thereof are alternately connected through surface-back stitching or double-sided organization, and a plurality of micro-channels for unidirectional moisture conduction are formed therebetween; the second thin layer is a zirconium-magnesium@SiO2 core-shell nanoparticle coating generated in situ and mediated by extract of Taiping flower, and is anchored to the surface of the first thin layer; the magnesium element and the zirconium element in the coating form a functional gradient distribution along the thickness direction of the first thin layer, the mass concentration of the zirconium element in the outer layer region is higher than that in the inner layer region, and the mass concentration of the magnesium element in the inner layer region is higher than that in the outer layer region. The aramid protective fabric has excellent flame-retardant performance, broad-spectrum antibacterial and mildew-proof performance, high washing resistance and good thermal-wet comfort.

Description

Technical Field

[0001] This invention relates to the field of protective fabric technology, specifically to an intrinsically flame-retardant, high-strength aramid protective fabric and its preparation method. Background Technology

[0002] Traditional flame-retardant protective fabrics mostly rely on the addition of flame retardants in the finishing process to achieve flame-retardant effects, which has problems such as poor durability, stiff hand feel, and poor environmental performance. Although aramid is an intrinsically flame-retardant fiber, existing aramid flame-retardant fabrics still generally suffer from defects such as high basis weight, insufficient softness, and lack of composite functions such as antibacterial, mildew-proof, and moisture-wicking properties.

[0003] Aramids, especially para-aramids (e.g., Kevlar) ® Due to its high strength, high modulus, high temperature resistance, and intrinsic flame retardancy, aramid fiber is widely used in personal protective equipment in high-risk fields such as fire fighting, military and police, and aerospace. However, the high crystallinity, strong chemical inertness, and extremely few active functional groups of aramid fiber surface result in weak interfacial adhesion between it and functional coatings. Traditional finishing coatings are prone to peeling and failure under harsh conditions such as repeated washing and friction, seriously affecting the service life and safety of protective equipment.

[0004] To endow aramid fabrics with multifunctionality, existing technologies mainly employ the following strategies: One approach is to activate the surface through plasma treatment or chemical etching to introduce polar groups and increase the surface energy of the fiber. However, a single activation treatment is difficult to achieve long-term anchoring, and the coating is still easy to fall off after multiple washes. Secondly, silane coupling agents or chitosan are introduced as bridging grafts of functional nanoparticles (such as MgO, ZrO2, AgNPs, etc.). However, there is a lack of synergistic design between different functional components, and antibacterial and flame-retardant components often interfere with each other. Moreover, most technologies can only withstand 5-100 washes, making it difficult to achieve long-term synergistic durability of dual functions. Third, one-way moisture-guiding microchannels are constructed through structural designs such as connecting double-layer tissues to improve thermal and humid comfort. However, this structure has poor compatibility with surface coatings. After coating, the microchannels are often blocked or the wetting gradient is destroyed, making it difficult to balance moisture-guiding function and coating anchoring.

[0005] Furthermore, while plant extracts (such as pomegranate peel, eucalyptus leaves, and tea polyphenols) have been used in existing technologies to mediate the synthesis of metal nanoparticles, their active ingredients, such as polyphenols and flavonoids, typically function as both reducing agents and stabilizers. However, these applications are mostly limited to achieving a single function (such as antibacterial or staining), and the synergistic effect between their multiple components has not yet been utilized to achieve a synergistic effect of flame retardancy and antibacterial properties in the same coating.

[0006] Taiping Flower ( PhiladelphianRupr. is a common perennial deciduous shrub in northern mountain forests, belonging to the genus Rupr. in the family Saxifragaceae. It is also known as Jingshan Plum or Beijing Plum. Its methanol, butanol, and water extracts all contain coumarin compounds (calculated as umbelliferone), but to date, there are no reports of its applications in the textile technology field.

[0007] Based on this, the present invention provides an intrinsically flame-retardant, high-strength aramid protective fabric. It constructs one-way moisture-wicking microchannels through an interlocking structure and utilizes extracts of *Euphorbia tirucalli*, combined with the synergistic effects of magnesium salts, zirconium salts, and chitosan, supplemented by a coumarin-aluminum-zirconium hybrid coupling agent crosslinking network and synergistic anchoring with the SiO2 shell. This aims to achieve spatial separation and synergy of flame-retardant and antibacterial functions, and significantly improve the fabric's washability, mechanical strength, and thermal and moisture comfort. This provides a new strategy for the multifunctional integration and ultra-durable design of personal protective equipment. Summary of the Invention

[0008] Therefore, the present invention provides an intrinsically flame-retardant, high-strength aramid protective fabric and its preparation method to overcome the shortcomings of the prior art.

[0009] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, an intrinsically flame-retardant, high-strength aramid protective fabric is provided, the protective fabric comprising a first thin layer and a second thin layer; the second thin layer is loaded on the outer surface of the first thin layer; The first thin layer is a single-layer fabric structure, which is divided into an outer layer region and an inner layer region from the outside to the inside in the fabric thickness direction. The outer layer region and the inner layer region are connected alternately by face-to-face bonding or double-sided weave, forming a number of microchannels for unidirectional moisture conduction between the outer layer region and the inner layer region. The second thin layer is a zirconium-magnesium@SiO2 core-shell nanoparticle coating generated in situ through the extraction of *Euphorbia pekinensis* extract; the zirconium-magnesium@SiO2 core-shell nanoparticle coating is anchored to the surface of the first thin layer; In the coating, magnesium and zirconium elements form a functional gradient distribution along the thickness direction of the first thin layer. The mass concentration of zirconium element in the outer layer region of the coating is higher than that in the inner layer region, and the mass concentration of magnesium element in the inner layer region is higher than that in the outer layer region.

[0010] Furthermore, the zirconium magnesium@SiO2 core-shell nanoparticle coating is anchored to the surface of the first thin layer through a cross-linked network formed by coumarin-aluminum zirconium hybrid coupling agent and chitosan.

[0011] Furthermore, the coumarin-aluminum zirconium hybrid coupling agent is prepared by coordination reaction of *Euphorbia pekinensis* extract and aluminum zirconate coupling agent.

[0012] Furthermore, the aramid is para-aramid.

[0013] According to a second aspect of the present invention, a method for preparing an intrinsically flame-retardant, high-strength aramid protective fabric is provided, comprising the following steps: S1. Aramid fibers are woven by joining the inner and outer sides or by double-sided weaving to form an aramid fabric with unidirectional moisture-wicking microchannels. S2. After the aramid fabric in step S1 is subjected to alkali reduction treatment and plasma surface activation, it is placed in a dye bath containing aramid extract, aramid dyeing carrier, cationic dye, disperse dye and acetate-sodium acetate buffer system for dyeing treatment to obtain dyed aramid fabric. The method for alkali reduction treatment is as follows: The aramid fabric was immersed in a sodium hydroxide (NaOH) solution with a concentration of 60-90 g / L at 85-95℃ for 8-12 minutes.

[0014] The methods for plasma surface activation are as follows: After the alkali reduction treatment is completed, a dielectric barrier discharge cold plasma device is used to treat the sample for 1-3 minutes in an O2 atmosphere at a power of 100-200W.

[0015] The preparation method of the extract of *Euphorbia hirta* is as follows: Take tender branches and leaves of *Euphorbia hirta*, remove impurities, wash, and dry at 40-50℃ to constant weight. Grind and pass through a 40-60 mesh sieve to obtain powder. Mix the powder with a 60%-80% ethanol aqueous solution at a material-to-liquid ratio of 1g:(10-30)mL. Reflux and extract at 60-65℃ for 60-90min. After cooling, vacuum filter at 0.07-0.09MPa for 10-30min and collect the filtrate. Extract the residue again under the same conditions and combine the two filtrates. Concentrate the combined filtrate under reduced pressure (temperature 50-60℃, vacuum degree not lower than 0.085MPa) to 1 / 2-1 / 3 of the original volume, and spray dry (inlet air temperature 140-160℃, outlet air temperature 70-80℃) to obtain *Euphorbia hirta* extract.

[0016] The staining process is as follows: Mix 5-15 g / L of *Euphorbia pekinensis* extract, 40-70 g / L of amide carrier (e.g., VKOOT N900), 1%-3% (owf) (owf) (owf) (of the aramid fabric) of cationic dye (e.g., Cationic Blue FGL), and 1%-3% (owf) (owf) (owf) (of the aramid fabric) (of disperse dye (Disperse Blue 2BLN)). Adjust the pH of the dye bath to 4.0-4.5 using a 0.1-0.2 mol / L acetate-sodium acetate buffer system. Then, raise the system temperature to 120-140℃ at a rate of 0.8-1.2℃ / min and dye at this temperature for 50-70 min. After dyeing, add 2-3 g / L of sodium sulfite and treat at 70-80℃ for 10-15 min to remove excess dye.

[0017] S3. The dyed aramid fabric from step S2 is subjected to cross-linking fixation, heat setting and softening finishing, and dried to obtain the pretreated aramid fabric. The cross-linking and color-fixing methods are as follows: The dyed aramid fabric is immersed in deionized water containing 20-30 g / L tricyclodecanediethanol bissilane crosslinking agent, the pH is adjusted to 6.0-6.5, and it is treated at 70-80℃ for 10-15 min. The preparation method of the tricyclodecane-diethanol bissilane crosslinking agent is as follows: Tricyclodecanediethanol (TCD) and dibutyltin dilaurate (DBTDL) were dissolved in anhydrous toluene and heated and stirred under an inert gas atmosphere (such as nitrogen). Then, γ-glycidoxypropyltrimethoxysilane was added dropwise and reacted at 80-120℃ for 4-8 hours. After the reaction was completed, the tricyclodecanediethanol disilane crosslinking agent was obtained by vacuum distillation (temperature 60-80℃, pressure <10mmHg). The molar ratio of tricyclodecanediethanol and γ-glycidoxypropyltrimethoxysilane is 1:(2-2.4); the amount of dibutyltin dilaurate (DBTDL) added is 0.1wt.%-0.3wt.% of the total mass of tricyclodecanediethanol and γ-glycidoxypropyltrimethoxysilane.

[0018] The heat setting method is as follows: After cross-linking and color fixing are completed, the dyed aramid fabric is heat-set at 170-180℃ for 35-45 seconds.

[0019] The following are methods for softening and finishing: After heat setting, the dyed aramid fabric is immersed in a softening liquid containing 20-30 g / L of fluffy amino silicone oil (e.g., RH-NB-8438) for 6-10 minutes at room temperature, with the pick-up rate controlled at 70%-80%, and then dried at 100-120℃ until no liquid remains.

[0020] S4. The pretreated aramid fabric in step S3 is subjected to plasma activation and acrylic acid grafting to introduce a polyacrylic acid graft layer to obtain a modified aramid fabric. The method for plasma activation and acrylic acid grafting is as follows: The pretreated aramid fabric is placed in a plasma treatment chamber, evacuated to <10Pa, and treated at 100-300W for 5-10min. Under vacuum conditions, acrylic acid that has been treated by vacuum distillation (temperature 60-80℃, pressure <10mmHg) is directly injected into the chamber at a rate of 1.5-2mL per gram of fabric, and reacted at 50-60℃ for 30-45min.

[0021] S5. Immerse the modified aramid fabric from step S4 in deionized water containing magnesium and zirconium salts, and pre-bake at 55-65℃ for 2-4 minutes to obtain an aramid fabric loaded with zirconium-magnesium precursors; during this process, the carboxyl groups introduced on the surface of the modified aramid fabric through acrylic acid grafting react with Mg... 2+ Ion exchange and coordination anchoring will bring higher concentrations of Mg to the surface. 2+ (15-25 g / L) preferentially anchors to the surface of modified aramid fabrics and the inner walls of microchannels, while lower concentrations of Zr... 4+ (5-10 g / L) was also introduced simultaneously, providing a precursor basis for the inner layer rich in Mg in the subsequent functional gradient distribution; S6. The aramid fabric loaded with zirconium-magnesium precursor from step S5 is immersed in a mixture containing *Pyrrosia lingua* extract, magnesium salt, zirconium salt, SiO2 precursor, chitosan, coumarin-aluminum-zirconium hybrid coupling agent, and auxiliaries. After padding and baking, an aramid fabric loaded with zirconium-magnesium@SiO2 core-shell nanoparticle coating is obtained. In this process, the polyphenolic components in *Pyrrosia lingua* extract are used to react with the Mg... 2+ and Zr 4+ Differences in coordination stability constants (i.e., Zr) 4+ The coordination stability constant of Mg is higher than that of Mg 2+ (3-5 orders of magnitude higher), driving higher concentrations of Zr 4+ (25-35 g / L) migrates and enriches to the outer layer, forming a ZrO2 flame-retardant layer, while Mg introduced in step S5 is simultaneously... 2+ Locked in the inner layer; in addition, the SiO2 precursor condenses during baking to form a SiO2 shell, which covers the outer surface of the core; The methods for padding and baking are as follows: After adjusting the pH of the mixture to 8-10, the aramid fabric loaded with zirconium magnesium precursor is immersed in it and subjected to a two-dip two-roll process (roll pressure of 0.1-0.3 MPa, control the roll residue rate to 70%-80%), followed by baking at 160-170℃ for 3-5 minutes.

[0022] S7. The aramid fabric loaded with zirconium magnesium@SiO2 core-shell nanoparticle coating in step S6 is subjected to one-sided hydrophobic modification, and then washed, dried and heat-set to obtain aramid protective fabric.

[0023] The method for single-sided hydrophobic modification is as follows: Lay the aramid fabric loaded with zirconium magnesium@SiO2 core-shell nanoparticle coating flat, cover the uncoated side with a solvent-resistant protective film (e.g., polytetrafluoroethylene film) to prevent the uncoated side from hydrophobic modification treatment and maintain its original hydrophilic properties; use a spray gun to uniformly spray the coating liquid onto the coated side, let it air dry at room temperature for 5-10 minutes, dry it at 100-120℃ for 5-10 minutes, and then set it at 150-160℃ for 5-10 minutes. The spraying solution is a 95% ethanol solution containing 3wt.%-6wt.% hexadecyltrimethoxysilane (HDTMS), and the pH is adjusted to 8-10 with 25%-28% ammonia. The spray gun pressure is 0.2-0.3 MPa, the spray gun distance is 15-25 cm, and the spraying volume is 30-50 mL / m. 2 (Based on wet conditions).

[0024] The washing, drying, and heat-setting methods are as follows: Wash the hydrophobically modified aramid fabric loaded with zirconium magnesium@SiO2 core-shell nanoparticle coating 2-4 times with deionized water, dry it at 75-85℃ until there is no liquid, and then fix it at 100-120℃ for 3-5 minutes.

[0025] Furthermore, the preparation method of the coumarin-aluminum-zirconium hybrid coupling agent in step S6 is as follows: (1) Take the extract of the flower of the flower, perform chromatography, elution, collect the elution fraction, concentrate under reduced pressure, freeze dry, and obtain the coumarin component; The methods for chromatography, elution, and collection of the eluted fraction are as follows: 30-60 mesh polyamide column chromatography was used, with gradient elution of 30%-95% ethanol and water. Thin-layer chromatography (TLC) was used for monitoring, with silica gel G plate as the stationary phase and ethyl acetate, formic acid and water in a volume ratio of 8:1:1 as the developing solvent. The samples were examined under UV light at 254 nm and 365 nm. The 50% ethanol eluent fractions containing the same characteristic spots of coumarins (Rf values ​​in the range of 0.5-0.7) were combined. The combined fractions were concentrated to 1 / 10-1 / 12 of the original volume under reduced pressure at 50-60℃ and a vacuum degree of not less than 0.085 MPa. After pre-freezing at -55~-45℃ for 6-8 h, they were dried at -65~-45℃ and a pressure not exceeding 20 Pa for 16-20 h. The eluent fraction containing coumarin components was collected. The peak area of ​​coumarin compounds was not less than 40% by HPLC normalization.

[0026] (2) After mixing the coumarin components obtained in step (1) with anhydrous N,N-dimethylformamide at a ratio of 1g:(10-20)mL, triethylamine is added and the mixture is heated to 70°C under nitrogen protection. Then, aluminum zirconate coupling agent is slowly added dropwise and the mixture is stirred and refluxed under nitrogen protection at 65-75°C for 3-4 hours to form a coumarin-aluminum zirconium hybrid complex. (3) After the reaction is completed, the mixture is concentrated under reduced pressure and washed 2-3 times with anhydrous ethanol and dried under vacuum to obtain the coumarin-aluminum zirconium hybrid coupling agent.

[0027] Furthermore, the mass ratio of coumarin components to aluminum zirconate coupling agent is 1:(2-4); the ratio of triethylamine to coumarin components is 1g:(0.4-0.6)mL.

[0028] Furthermore, in step S5: the molar ratio of magnesium salt to zirconium salt is (9-12):1; In step S6: the mass ratio of the addition of *Eupatorium fortunei* extract to magnesium salt is (2-3):1; the molar ratio of magnesium salt to zirconium salt is (0.5-1.3):1.

[0029] Further, in step S5: the concentration of the magnesium salt is 15-25 g / L; the concentration of the zirconium salt is 5-10 g / L; In step S6: the concentration of the *Eupatorium fortunei* extract is 10-30 g / L; the concentration of the magnesium salt is 5-10 g / L; the concentration of the zirconium salt is 25-35 g / L; the amount of the SiO2 precursor added is 50-80 g / L; the amount of chitosan added is 10-20 g / L; the amount of the coumarin-aluminum-zirconium hybrid coupling agent added is 5-10 g / L; and the amount of the auxiliary agent added is 0.5-2 g / L.

[0030] Further, the magnesium salt is selected from at least one of magnesium acetate, magnesium chloride, and magnesium nitrate; the zirconium salt is selected from at least one of zirconium acetate, zirconium carbonate, and zirconium oxychloride; the SiO2 precursor is selected from at least one of silica sol, tetraethyl orthosilicate, and sodium silicate; and the additive is selected from at least one of sodium dodecyl diphenyl ether disulfonate (C12-MADS), fatty acid polyoxyethylene ether (AEO-9), and polyvinylpyrrolidone (PVP).

[0031] Further, the magnesium salt is magnesium acetate; the zirconium salt is zirconium acetate; the SiO2 precursor is tetraethyl orthosilicate (TEOS); and the additive is sodium dodecyl diphenyl ether disulfonate (C12-MADS).

[0032] In one specific embodiment, the preparation method of the tetraethyl orthosilicate (TEOS) sol-gel reaction solution is as follows: Anhydrous ethanol and deionized water were mixed, and the pH was adjusted to 8-10 with dilute ammonia. Tetraethyl orthosilicate (TEOS) was slowly added under stirring and stirred for 20-40 minutes to obtain a tetraethyl orthosilicate (TEOS) sol-gel reaction solution. The volume ratio of tetraethyl orthosilicate (TEOS), anhydrous ethanol, and deionized water is 1:4:(1-2).

[0033] According to a third aspect of the present invention, the application of the aramid protective fabric prepared by the said preparation method in the preparation of personal protective equipment is provided.

[0034] Compared with the prior art, the present invention has the following advantages: (1) The aramid protective fabric of the present invention achieves chemical anchoring through covalent bonding of a tricyclodecanediethanol bissilane crosslinking agent and coordination crosslinking of a coumarin-aluminum zirconium hybrid coupling agent; the dense coating structure formed on its surface, consisting of a SiO2 shell, a ZrO2 outer layer, and a crosslinking network, provides physical shielding; the polyphenolic components in the extract of *Euphorbia pekinensis* in its system have a positive effect on Mg 2+ and Zr 4+ The differentiated coordination ability of the coating drives the gradient distribution and slow-release regulation of the two components in the thickness direction, achieving dynamic coordination. These three mechanisms work synergistically to form a strong covalent bond and three-dimensional cross-linked network between the functional coating and the aramid fiber. Simultaneously, the SiO2 shell provides triple protection to the metal oxide core—physical anchoring, chemical isolation, and anti-agglomeration dispersion—contributing to the integrity of the coating structure during use. The resulting aramid protective fabric retains its antibacterial activity, flame retardant properties, and mechanical strength after 150 standard washes, overcoming the defect of traditional coatings where functionality decreases with washing cycles.

[0035] (2) The aramid protective fabric of the present invention utilizes the polyphenolic components in the extract of *Euphorbia milii* to inhibit the formation of Mg. 2+ and Zr4+ Significant differences in coordination stability constants (i.e., Zr) 4+ The coordination stability constant of Mg is higher than that of Mg 2+ (3-5 orders of magnitude higher), driving Zr during baking. 4+ The ZrO2 flame-retardant layer migrates and accumulates to the outer layer of the fiber, while Mg... 2+ The MgO antibacterial layer migrates and accumulates in the inner layer and on the inner wall of the unidirectional moisture-guiding microchannels. This functional gradient distribution, with the outer layer rich in Zr and the inner layer rich in Mg, achieves spatial separation of flame-retardant and antibacterial functions in the thickness direction, avoiding the mutual interference caused by direct mixing of flame retardants and antibacterial agents in traditional coatings.

[0036] (3) This invention combines fabric structure design with single-sided hydrophobic modification technology. Utilizing a microchannel structure constructed from an inner-outer or double-sided weave, combined with single-sided asymmetric wetting modification, a wetting gradient is formed in the fabric thickness direction, with the inner side being hydrophilic and the outer side hydrophobic. This design allows sweat to be rapidly pumped from the skin side to the outer surface for evaporation, while effectively preventing external moisture backflow. This microchannel structure is compatible with the functional gradient distribution, with the MgO antibacterial layer enriched in the inner wall of the microchannels, achieving precise positioning of the antibacterial function. Simultaneously, this system does not significantly increase the fabric weight, imparting softness and breathability to the fabric, and improving thermal and humid comfort under prolonged wear conditions.

[0037] (4) This invention uses the extract of *Euphorbia hirta* as the core functional auxiliary agent. Its rich polyphenols and flavonoids act as both natural dye auxiliary agents and biological reducing agents in the dyeing process. After plasma grafting, it provides additional hydrogen bond anchor sites and acts as a central mediator for bimetallic coordination competition in the subsequent sol-gel process, regulating Zr 4+ With Mg 2+ The fabric exhibits differentiated migration behavior. This end-to-end, multi-purpose design simplifies process operations, reduces the amount of added chemicals, and imparts bioactive characteristics to the fabric. The entire process is gentle, aligning with the principles of sustainable development and clean production.

[0038] (5) In this invention, the cross-linked network synergistically constructed by chitosan and coumarin-aluminum zirconium hybrid coupling agent forms a composite coating structure together with the SiO2 shell, which can buffer external impact and inhibit crack propagation; at the same time, the functional gradient distribution helps to alleviate local stress concentration inside the coating and improve the fatigue resistance of the coating. Therefore, the fabric can still maintain good breaking strength and tear strength while meeting the requirements of lightweight design, thus meeting the mechanical strength requirements of personal protective equipment such as fire fighting and military police equipment.

[0039] In summary, this invention provides a high-performance aramid protective fabric that integrates intrinsic flame retardancy, high durability, antibacterial and mildew resistance, unidirectional moisture wicking, and lightweight high strength. It offers a new technical approach to overcome the problems of poor washability and low functional compatibility of traditional multifunctional coatings and has good application prospects in the field of personal protective equipment. Detailed Implementation

[0040] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0041] According to a first aspect of the present invention, an intrinsically flame-retardant, high-strength aramid protective fabric is provided, the protective fabric comprising a first thin layer and a second thin layer; the second thin layer is loaded on the outer surface of the first thin layer; The first thin layer is a single-layer fabric structure, which is divided into an outer layer region and an inner layer region from the outside to the inside in the fabric thickness direction. The outer layer region and the inner layer region are connected by face-to-face bonding or double-sided weave, forming a number of microchannels for unidirectional moisture conduction between the outer layer region and the inner layer region. The second thin layer is a zirconium-magnesium@SiO2 core-shell nanoparticle coating generated in situ through the extraction of *Euphorbia pekinensis*; the zirconium-magnesium@SiO2 core-shell nanoparticle coating is anchored to the surface of the first thin layer. In the coating, magnesium and zirconium elements form a functional gradient distribution along the thickness direction of the first thin layer. The mass concentration of zirconium element in the outer layer region of the coating is higher than that in the inner layer region, and the mass concentration of magnesium element in the inner layer region is higher than that in the outer layer region.

[0042] Furthermore, the zirconium magnesium@SiO2 core-shell nanoparticle coating is anchored to the surface of the first thin layer through a cross-linked network formed by coumarin-aluminum zirconium hybrid coupling agent and chitosan.

[0043] Furthermore, the coumarin-aluminum zirconium hybrid coupling agent is prepared by coordination reaction of *Euphorbia hirta* extract and aluminum zirconate coupling agent.

[0044] Furthermore, the aramid is a para-aramid.

[0045] According to a second aspect of the present invention, a method for preparing an intrinsically flame-retardant, high-strength aramid protective fabric is provided, comprising the following steps: S1. Aramid fibers are woven by joining the inner and outer sides or by double-sided weaving to form an aramid fabric with unidirectional moisture-wicking microchannels. S2. After the aramid fabric in step S1 is subjected to alkali reduction treatment and plasma surface activation, it is placed in a dye bath containing aramid extract, aramid dyeing carrier, cationic dye, disperse dye and acetate-sodium acetate buffer system for dyeing treatment to obtain dyed aramid fabric. The method for alkali reduction treatment is as follows: The aramid fabric was immersed in a sodium hydroxide (NaOH) solution with a concentration of 60-90 g / L at 85-95℃ for 8-12 minutes.

[0046] The methods for plasma surface activation are as follows: After the alkali reduction treatment is completed, a dielectric barrier discharge cold plasma device is used to treat the sample for 1-3 minutes in an O2 atmosphere at a power of 100-200W.

[0047] The preparation method of the extract of *Euphorbia hirta* is as follows: Take tender branches and leaves of *Euphorbia hirta*, remove impurities, wash, and dry at 40-50℃ to constant weight. Grind and pass through a 40-60 mesh sieve to obtain powder. Mix the powder with a 60%-80% ethanol aqueous solution at a material-to-liquid ratio of 1g:(10-30)mL. Reflux and extract at 60-65℃ for 60-90min. After cooling, vacuum filter at 0.07-0.09MPa for 10-30min and collect the filtrate. Extract the residue again under the same conditions and combine the two filtrates. Concentrate the combined filtrate under reduced pressure and spray dry (inlet air temperature 140-160℃, outlet air temperature 70-80℃) to obtain *Euphorbia hirta* extract.

[0048] The staining process is as follows: Mix 5-15 g / L of *Euphorbia pekinensis* extract, 40-70 g / L of amide carrier (e.g., VKOOT N900), 1%-3% (owf) (owf) (owf) (of the aramid fabric) of cationic dye (e.g., Cationic Blue FGL), and 1%-3% (owf) (owf) (owf) (of the aramid fabric) (of disperse dye (Disperse Blue 2BLN)). Adjust the pH of the dye bath to 4.0-4.5 using a 0.1-0.2 mol / L acetate-sodium acetate buffer system. Then, raise the system temperature to 120-140℃ at a rate of 0.8-1.2℃ / min and dye at this temperature for 50-70 min. After dyeing, add 2-3 g / L of sodium sulfite and treat at 70-80℃ for 10-15 min to remove excess dye.

[0049] S3. The dyed aramid fabric from step S2 is subjected to cross-linking fixation, heat setting and softening finishing, and dried to obtain the pretreated aramid fabric. The cross-linking and color-fixing methods are as follows: Immerse the dyed aramid fabric in deionized water containing 20-30 g / L tricyclodecanediethanol bissilane crosslinking agent, adjust the pH to 6.0-6.5, and treat at 70-80℃ for 10-15 min. The preparation method of the tricyclodecane-diethanol bissilane crosslinking agent is as follows: Tricyclodecanediethanol (TCD) and dibutyltin dilaurate (DBTDL) were dissolved in anhydrous toluene and heated and stirred under an inert gas atmosphere (such as nitrogen). Then, γ-glycidoxypropyltrimethoxysilane was added dropwise and reacted at 80-120℃ for 4-8 hours. After the reaction was completed, the tricyclodecanediethanol disilane crosslinking agent was obtained by vacuum distillation (temperature 60-80℃, pressure <10mmHg). The molar ratio of tricyclodecanediethanol and γ-glycidoxypropyltrimethoxysilane is 1:(2-2.4); the amount of dibutyltin dilaurate (DBTDL) added is 0.1wt.%-0.3wt.% of the total mass of tricyclodecanediethanol and γ-glycidoxypropyltrimethoxysilane.

[0050] The heat setting method is as follows: After cross-linking and color fixing, the dyed aramid fabric is heat-set at 170-180℃ for 35-45 seconds.

[0051] The following are methods for softening and finishing: After heat setting, the dyed aramid fabric is immersed in a softening solution containing 20-30 g / L of fluffy amino silicone oil (e.g., RH-NB-8438) for 6-10 minutes at room temperature, with the pick-up rate controlled at 70%-80%, and then dried at 100-120℃.

[0052] S4. The pretreated aramid fabric in step S3 is subjected to plasma activation and acrylic acid grafting to introduce a polyacrylic acid graft layer to obtain a modified aramid fabric. The method for plasma activation and acrylic acid grafting is as follows: The pretreated aramid fabric is placed in the plasma treatment chamber and evacuated to <10Pa. It is then treated at 100-300W for 5-10 minutes. While maintaining the vacuum, acrylic acid that has been treated by vacuum distillation (temperature 60-80℃, pressure <10mmHg) is directly injected into the chamber at a rate of 1.5-2mL per gram of fabric. The mixture is then reacted at 50-60℃ for 30-45 minutes.

[0053] S5. Immerse the modified aramid fabric from step S4 in deionized water containing magnesium and zirconium salts, and pre-bake at 55-65℃ for 2-4 minutes to obtain an aramid fabric loaded with zirconium-magnesium precursors; during this process, the carboxyl groups introduced on the surface of the modified aramid fabric through acrylic acid grafting react with Mg... 2+ Ion exchange and coordination anchoring will bring higher concentrations of Mg to the surface.2+ (15-25 g / L) preferentially anchors to the surface of modified aramid fabrics and the inner walls of microchannels, while lower concentrations of Zr... 4+ (5-10 g / L) was also introduced simultaneously, providing a precursor basis for the inner layer rich in Mg in the subsequent functional gradient distribution; S6. The aramid fabric loaded with zirconium-magnesium precursor from step S5 is immersed in a mixture containing *Pyrrosia lingua* extract, magnesium salt, zirconium salt, SiO2 precursor, chitosan, coumarin-aluminum-zirconium hybrid coupling agent, and auxiliaries. After padding and baking, an aramid fabric loaded with zirconium-magnesium@SiO2 core-shell nanoparticle coating is obtained. In this process, the polyphenolic components in *Pyrrosia lingua* extract are used to react with the Mg... 2+ and Zr 4+ Differences in coordination stability constants (i.e., Zr) 4+ The coordination stability constant of Mg is higher than that of Mg 2+ (3-5 orders of magnitude higher), driving higher concentrations of Zr 4+ (25-35 g / L) migrates and enriches to the outer layer, forming a ZrO2 flame-retardant layer, while Mg introduced in step S5 is simultaneously... 2+ Locked in the inner layer; in addition, the SiO2 precursor condenses during baking to form a SiO2 shell, which covers the outer surface of the core; The methods for padding and baking are as follows: After adjusting the pH of the mixture to 8-10, the aramid fabric loaded with zirconium magnesium precursor is immersed in it and subjected to a two-dip two-roll process (roll pressure of 0.1-0.3MPa, control the roll residue rate of 70%-80%), and then baked at 160-170℃ for 3-5 minutes.

[0054] S7. The aramid fabric loaded with zirconium magnesium@SiO2 core-shell nanoparticle coating in step S6 is subjected to one-sided hydrophobic modification, and then washed, dried and heat-set to obtain aramid protective fabric.

[0055] The method for single-sided hydrophobic modification is as follows: Lay out an aramid fabric coated with zirconium magnesium@SiO2 core-shell nanoparticles. Cover the uncoated side with a solvent-resistant protective film (e.g., polytetrafluoroethylene film) to prevent hydrophobic modification and maintain its original hydrophilic properties. Use a spray gun to uniformly spray a 95% ethanol solution containing hexadecyltrimethoxysilane (HDTMS) and ammonia onto the coated side. After spraying, allow it to air dry at room temperature for 5-10 minutes, dry it at 100-120℃ for 5-10 minutes, and then set it at 150-160℃ for 5-10 minutes. The spraying solution is a 95% ethanol solution containing 3wt.%-6wt.% hexadecyltrimethoxysilane (HDTMS), and the pH is adjusted to 8-10 with 25%-28% ammonia. The spray gun pressure is 0.2-0.3 MPa, the spray gun distance is 15-25 cm, and the spraying volume is 30-50 mL / m. 2 (Based on wet conditions).

[0056] The washing, drying, and heat-setting methods are as follows: Wash the hydrophobically modified aramid fabric loaded with zirconium magnesium@SiO2 core-shell nanoparticle coating 2-4 times with deionized water, dry it at 75-85℃, and then fix it at 100-120℃ for 3-5 minutes.

[0057] Furthermore, the preparation method of the coumarin-aluminum-zirconium hybrid coupling agent in step S6 is as follows: (1) Take the extract of the flower of the flower, perform chromatography, elution, collect the elution fraction, concentrate under reduced pressure, freeze dry, and obtain the coumarin component; The methods for chromatography, elution, and collection of the eluted fraction are as follows: 30-60 mesh polyamide column chromatography was used, with gradient elution of 30%-95% ethanol and water. Thin-layer chromatography (TLC) was used for monitoring, with silica gel G plate as the stationary phase and ethyl acetate, formic acid and water in a volume ratio of 8:1:1 as the developing solvent. The samples were examined under UV light at 254 nm and 365 nm. The 50% ethanol eluent fractions containing the same characteristic spots of coumarins (Rf values ​​in the range of 0.5-0.7) were combined. The combined fractions were concentrated to 1 / 10-1 / 12 of the original volume under reduced pressure at 50-60℃ and a vacuum degree of not less than 0.085 MPa. After pre-freezing at -55~-45℃ for 6-8 h, they were dried at -65~-45℃ and a pressure not exceeding 20 Pa for 16-20 h. The eluent fraction containing coumarin components was collected. The peak area of ​​coumarin compounds was not less than 40% by HPLC normalization.

[0058] (2) After mixing the coumarin components obtained in step (1) with anhydrous N,N-dimethylformamide at a ratio of 1g:(10-20)mL, triethylamine is added and the mixture is heated to 70°C under nitrogen protection. Then, aluminum zirconate coupling agent is slowly added dropwise and the mixture is stirred and refluxed under nitrogen protection at 70°C for 3-4 hours to form a coumarin-aluminum zirconium hybrid complex. (3) After the reaction is completed, the mixture is concentrated under reduced pressure and washed 2-3 times with anhydrous ethanol and dried under vacuum to obtain the coumarin-aluminum zirconium hybrid coupling agent.

[0059] Furthermore, the mass ratio of coumarin components to aluminum zirconate coupling agent is 1:(2-4); the ratio of triethylamine to coumarin components is 1g:(0.4-0.6)mL.

[0060] Furthermore, in step S5: the molar ratio of magnesium salt to zirconium salt is (9-12):1; In step S6: the mass ratio of the addition of *Eupatorium fortunei* extract to magnesium salt is (2-3):1; the molar ratio of magnesium salt to zirconium salt is (0.5-1.3):1.

[0061] Further, in step S5: the concentration of magnesium salt is 15-25 g / L; the concentration of zirconium salt is 5-10 g / L; In step S6: the concentration of the extract of *Eupatorium fortunei* is 10-30 g / L; the concentration of magnesium salt is 5-10 g / L; the concentration of zirconium salt is 25-35 g / L; the amount of SiO2 precursor added is 50-80 g / L; the amount of chitosan added is 10-20 g / L; the amount of coumarin-aluminum-zirconium hybrid coupling agent added is 5-10 g / L; and the amount of auxiliary agent added is 0.5-2 g / L.

[0062] Furthermore, the magnesium salt is selected from at least one of magnesium acetate, magnesium chloride, and magnesium nitrate; the zirconium salt is selected from at least one of zirconium acetate, zirconium carbonate, and zirconium oxychloride; the SiO2 precursor is selected from at least one of silica sol, tetraethyl orthosilicate, and sodium silicate; and the additive is selected from at least one of sodium dodecyl diphenyl ether disulfonate (C12-MADS), fatty acid polyoxyethylene ether (AEO-9), and polyvinylpyrrolidone (PVP).

[0063] Furthermore, the magnesium salt is magnesium acetate; the zirconium salt is zirconium acetate; the SiO2 precursor is tetraethyl orthosilicate (TEOS); and the additive is sodium dodecyl diphenyl ether disulfonate (C12-MADS).

[0064] In one specific embodiment, the SiO2 precursor is tetraethyl orthosilicate (TEOS) sol-gel reaction solution, and its preparation method is as follows: Anhydrous ethanol and deionized water were mixed, and the pH was adjusted to 8-10 with dilute ammonia. Tetraethyl orthosilicate (TEOS) was slowly added under stirring and stirred for 20-40 minutes to obtain a tetraethyl orthosilicate (TEOS) sol-gel reaction solution. The volume ratio of tetraethyl orthosilicate (TEOS), anhydrous ethanol, and deionized water is 1:4:(1-2).

[0065] According to a third aspect of the present invention, the application of the aramid protective fabric prepared by the preparation method in the preparation of personal protective equipment is provided.

[0066] Preparation Example 1 Preparation of tricyclodecanediethanol bissilane crosslinking agent In a three-necked flask equipped with a stirrer, reflux condenser, and thermometer, under nitrogen protection, 20.0 g of tricyclodecanediethanol (TCD) and 0.13 g of dibutyltin dilaurate (DBTDL) were dissolved in 150 mL of anhydrous toluene. The temperature was raised to 80 °C with continuous stirring. Subsequently, 52.9 g of γ-glycidoxypropyltrimethoxysilane (KH-560) was slowly added dropwise through a constant-pressure dropping funnel over a period of 30 min. After the addition was complete, the temperature was raised to 100 °C and the reaction was stirred for 6 h. After the reaction was completed, the reaction mixture was cooled to room temperature and distilled under reduced pressure at 70 °C and 8 mmHg to remove toluene and unreacted KH-560, yielding a tricyclodecanediethanol disilane crosslinking agent, which was a pale yellow viscous liquid.

[0067] Preparation Example 2 Preparation of extract from *Euphorbia hirta* Young branches and leaves of *Euphorbia lathyris* (current year's shoots) were collected, impurities were removed, and the leaves were washed and dried at 45°C to constant weight. The powder was then ground and passed through a 50-mesh sieve. 10g of the powder was added to 150mL of 75% ethanol aqueous solution, mixed evenly, and extracted by reflux at 65°C for 60min. After cooling to room temperature, the mixture was vacuum filtered at 0.08MPa for 20min, and the filtrate was collected. The residue was extracted again under the same conditions, and the two filtrates were combined. The combined filtrate was concentrated under reduced pressure at 55°C and 0.09MPa to half its original volume, and then spray-dried at an inlet air temperature of 140-160°C and an outlet air temperature of 70-80°C to obtain *Euphorbia lathyris* extract.

[0068] The above-mentioned extracts of *Euphorbia hirta* must meet the following requirements: The total polyphenols were determined by the Folin-Ciocalteu method (in gallic acid equivalent, GAE) to be no less than 50 mg GAE / g dry weight; The total flavonoids were determined by AlCl3 colorimetric method (in quercetin equivalent, QE) to be no less than 5 mg QE / g dry weight.

[0069] Preparation Example 3 Preparation of tetraethyl orthosilicate (TEOS) sol-gel reaction solution Mix 40 mL of anhydrous ethanol with 15 mL of deionized water, and adjust the pH to (9 ± 0.2) with dilute ammonia. Under stirring conditions, slowly add 10 mL of tetraethyl orthosilicate (TEOS) and continue stirring for 30 min to obtain a homogeneous and transparent tetraethyl orthosilicate (TEOS) sol-gel reaction solution with a TEOS content of 100 g / L.

[0070] Preparation Example 4 Preparation of coumarin-aluminum-zirconium hybrid coupling agents (1) Take 100 mL of the extract of *Euphorbia hirta* from Preparation Example 2 and perform polyamide column chromatography (30-60 mesh, column diameter 2.5 cm, column height 40 cm, column volume about 200 mL). Elute with deionized water, 30% ethanol, 50% ethanol, 70% ethanol and 95% ethanol for 2 column volumes each, at a flow rate of 1.2 mL / min. Collect 10 mL from each tube and detect the fractions in each tube by thin-layer chromatography (TLC): use silica gel G plate as stationary phase and ethyl acetate-formic acid-water (8:1:1, volume ratio) as developing solvent. Examine under ultraviolet light at 254 nm and 365 nm. Combine the 50% ethanol elution fractions containing the same characteristic spots of coumarins (Rf value about 0.5-0.7). The combined fractions were concentrated to 1 / 12 of their original volume under reduced pressure at 55℃ and 0.085MPa. The concentrate was transferred to a freeze-drying pan and pre-frozen at -45℃ for 7 hours. Then, it was placed in a freeze dryer and freeze-dried at -55℃ and 20Pa for 18 hours to obtain coumarin components (based on HPLC normalization, the proportion of chromatographic peak area belonging to coumarin compounds to the total peak area is not less than 40%).

[0071] (2) Dissolve 1g of the coumarin component obtained in step (1) in 20mL of anhydrous N,N-dimethylformamide (DMF), add 0.5mL of triethylamine, and heat to 70℃ under nitrogen protection; slowly add 3g of aluminum zirconate coupling agent (model TL-4, purchased from Chongqing Gaoyao Technology Co., Ltd.); after the addition is complete, continue stirring and reflux reaction for 3.5h under nitrogen protection at 70℃ to form a stable coumarin-aluminum zirconium hybrid complex.

[0072] (3) After the reaction is completed, the reaction product is concentrated under reduced pressure to 1 / 3 of the original volume, anhydrous ethanol is added to precipitate the product, and the product is filtered. The filter cake is washed three times with anhydrous ethanol and dried under vacuum at 50°C for 12 hours to obtain a light yellow solid powder, which is the coumarin-aluminum zirconium hybrid coupling agent.

[0073] Example 1 A method for preparing an intrinsically flame-retardant, high-strength aramid protective fabric includes the following steps: S1, Kevlar ® Aramid yarn (purchased from DuPont, USA) is woven by joining the inner and outer layers to form an aramid protective fabric with one-way moisture-wicking microchannels.

[0074] S2. The aramid fabric from step S1 is immersed in a 75g / L NaOH solution at 90°C for 10 minutes to perform alkali reduction treatment; then, it is treated with dielectric barrier discharge cold plasma at 150W in an O2 atmosphere for 2 minutes to perform surface activation. 5g of *Eupatorium fortunei* extract from Preparation Example 2, 70g of aramid dyeing carrier VKOOT N900 (purchased from UniVOOK Chemical), 3% (owf) cationic blue FGL (purchased from Shanghai Run Biotechnology Co., Ltd.), and 3% (owf) disperse blue 2BLN (purchased from Guangzhou Shuyang Daoerchi E-commerce Co., Ltd.) were dissolved in 1L of deionized water and mixed thoroughly to prepare a dyeing solution. The activated aramid fabric was placed in a dyeing machine, and the dyeing solution was added. The pH was adjusted to 4.2±0.2 using a 0.15mol / L acetate-sodium acetate buffer system (purchased from Jiangsu Maige Biotechnology Co., Ltd.). Subsequently, the system temperature was raised to 130℃ at a rate of 1℃ / min and dyed for 60min. After dyeing, 3g of sodium sulfite was added, and the mixture was treated at 75℃ for 12min to remove excess dye, yielding the dyed aramid fabric.

[0075] S3. Immerse the dyed aramid fabric from step S2 into 1L of deionized water containing 20g of the tricyclodecanediethanol bissilane crosslinking agent from Preparation Example 1, adjust the pH to 6.2±0.2, and treat at 75℃ for 12min. After treatment, heat set at 175℃ for 40s. Then, immerse the heat-set dyed aramid fabric into 1L of deionized water containing 30g / L of fluffy amino silicone oil (model RH-NB-8438, purchased from Ningbo Runhe High-tech Materials Technology Co., Ltd.), soak at room temperature for 8min, control the roll-off rate to 75%, and dry at 110℃ until there is no liquid to obtain the pretreated aramid fabric.

[0076] S4. Place the pretreated aramid fabric from step S3 into the plasma treatment chamber, evacuate to 5 Pa, and treat at 200 W for 10 min. Maintain the vacuum, and inject acrylic acid treated by vacuum distillation (temperature 70℃, pressure 5 mmHg) directly into the chamber at a rate of 1.8 mL per gram of fabric. React at 55℃ for 40 min to obtain the modified aramid fabric.

[0077] S5. Immerse the modified aramid fabric from step S4 into 1L of deionized water containing 15g magnesium acetate and 5g zirconium acetate, and pre-bake at 60°C for 3min to obtain the aramid fabric loaded with zirconium magnesium precursor. S6. Take 30g of the extract of *Euphorbia hirta* from Preparation Example 2, 10g of magnesium acetate and 30g of zirconium acetate, mix them together, add 500mL of 100g / L tetraethyl orthosilicate (TEOS) sol-gel reaction solution from Preparation Example 3, 20g of chitosan (pre-dissolved in 200mL of 5% HAc at 45℃), 10g of coumarin-aluminum zirconium hybrid coupling agent from Preparation Example 4 and 2g of sodium dodecyl diphenyl ether disulfonate (C12-MADS), adjust the pH to (9.2±0.2) with dilute ammonia, add deionized water to 1L, stir well to obtain a mixture.

[0078] The aramid fabric loaded with zirconium-magnesium precursors in step S5 is immersed in the above mixture and subjected to a two-dip two-roll process (roll pressure of 0.2 MPa, roll rate controlled at 75%), followed by baking at 165°C for 4 min to obtain an aramid fabric loaded with ZrO2 / MgO@SiO2 core-shell nanoparticle coating.

[0079] S7. Lay the aramid fabric loaded with the ZrO2 / MgO@SiO2 core-shell nanoparticle coating from step S6 flat, cover the uncoated surface with a polytetrafluoroethylene film, and use a spray gun (pressure 0.25MPa, spray distance 20cm) at a spray rate of 40mL / m. 2 (Wet condition) The coating layer was uniformly sprayed with a 95% ethanol solution containing 4.5 wt.% hexadecyltrimethoxysilane (HDTMS), and the pH was adjusted to (9.2±0.2) with 26% ammonia. After spraying, the coating was allowed to air dry at room temperature for 8 min, then dried at 110℃ for 8 min, and finally set at 155℃ for 8 min. The aramid fabric loaded with ZrO2 / MgO@SiO2 core-shell nanoparticles after hydrophobic modification was washed three times with deionized water, dried at 80°C until no liquid remained, and then set at 110°C for 4 minutes to obtain the aramid protective fabric.

[0080] Example 2 A method for preparing an intrinsically flame-retardant, high-strength aramid protective fabric includes the following steps: S1, Kevlar ® Aramid yarn (purchased from DuPont, USA) is woven by joining the inner and outer layers to form an aramid protective fabric with one-way moisture-wicking microchannels.

[0081] S2. The aramid fabric from step S1 is immersed in a 75g / L NaOH solution at 90°C for 10 minutes to perform alkali reduction treatment; then, it is treated with dielectric barrier discharge cold plasma at 150W in an O2 atmosphere for 2 minutes to perform surface activation. 15g of *Eupatorium fortunei* extract from Preparation Example 2, 40g of aramid dyeing carrier VKOOT N900 (purchased from UniVOOK Chemical), 1% (owf) cationic blue FGL (purchased from Shanghai Run Biotechnology Co., Ltd.), and 1% (owf) disperse blue 2BLN (purchased from Guangzhou Shuyang Daoerchi E-commerce Co., Ltd.) were dissolved in 1L of deionized water and mixed thoroughly to prepare a dyeing solution. The activated aramid fabric was placed in a dyeing machine, and the dyeing solution was added. The pH was adjusted to 4.2±0.2 using a 0.15mol / L acetate-sodium acetate buffer system (purchased from Jiangsu Maige Biotechnology Co., Ltd.). Subsequently, the system temperature was raised to 130℃ at a rate of 1℃ / min and dyed for 60min. After dyeing, 2g of sodium sulfite was added, and the mixture was treated at 75℃ for 12min to remove excess dye, resulting in the dyed aramid fabric.

[0082] S3. Immerse the dyed aramid fabric from step S2 into 1L of deionized water containing 30g of the tricyclodecanediethanol bissilane crosslinking agent from Preparation Example 1, adjust the pH to 6.2±0.2, and treat at 75℃ for 12min. After treatment, heat set at 175℃ for 40s. Then, immerse the heat-set dyed aramid fabric into 1L of deionized water containing 20g / L of fluffy amino silicone oil (model RH-NB-8438, purchased from Ningbo Runhe High-tech Materials Technology Co., Ltd.), soak at room temperature for 8min, control the roll-off rate to 75%, and dry at 110℃ until there is no liquid to obtain the pretreated aramid fabric.

[0083] S4. Place the pretreated aramid fabric from step S3 into the plasma treatment chamber, evacuate to 5 Pa, and treat at 200 W for 10 min. Maintain the vacuum, and inject acrylic acid treated by vacuum distillation (temperature 70℃, pressure 5 mmHg) directly into the chamber at a rate of 1.8 mL per gram of fabric. React at 55℃ for 40 min to obtain the modified aramid fabric.

[0084] S5. The modified aramid fabric from step S4 is immersed in 1L of deionized water containing 25g magnesium acetate and 10g zirconium acetate, and pre-baked at 60°C for 3min to obtain the aramid fabric loaded with zirconium magnesium precursor. S6. Take 10g of the extract of *Eupatorium fortunei* from Preparation Example 2, 5g of magnesium acetate and 35g of zirconium acetate, mix them together, add 800mL of 100g / L tetraethyl orthosilicate (TEOS) sol-gel reaction solution from Preparation Example 3, 10g of chitosan (pre-dissolved in 100mL of 5% HAc at 45℃), 5g of coumarin-aluminum zirconium hybrid coupling agent from Preparation Example 4 and 0.5g of sodium dodecyl diphenyl ether disulfonate (C12-MADS), adjust the pH to (9.2±0.2) with dilute ammonia, add deionized water to 1L, stir well to obtain a mixture.

[0085] The aramid fabric loaded with zirconium-magnesium precursors in step S5 is immersed in the above mixture and subjected to a two-dip two-roll process (roll pressure of 0.2 MPa, roll rate controlled at 75%), followed by baking at 165°C for 4 min to obtain an aramid fabric loaded with ZrO2 / MgO@SiO2 core-shell nanoparticle coating.

[0086] S7. Lay the aramid fabric loaded with the ZrO2 / MgO@SiO2 core-shell nanoparticle coating from step S6 flat, cover the uncoated surface with a polytetrafluoroethylene film, and use a spray gun (pressure 0.25MPa, spray distance 20cm) at a spray rate of 40mL / m. 2 (Wet condition) The coating layer was uniformly sprayed with a 95% ethanol solution containing 4.5 wt.% hexadecyltrimethoxysilane (HDTMS), and the pH was adjusted to (9.2±0.2) with 26% ammonia. After spraying, the coating was allowed to air dry at room temperature for 8 min, then dried at 110℃ for 8 min, and finally set at 155℃ for 8 min. The aramid fabric loaded with ZrO2 / MgO@SiO2 core-shell nanoparticles after hydrophobic modification was washed three times with deionized water, dried at 80°C until no liquid remained, and then set at 110°C for 4 minutes to obtain the aramid protective fabric.

[0087] Example 3 A method for preparing an intrinsically flame-retardant, high-strength aramid protective fabric includes the following steps: S1, Kevlar ® Aramid yarn (purchased from DuPont, USA) is woven by joining the inner and outer layers to form an aramid protective fabric with one-way moisture-wicking microchannels.

[0088] S2. The aramid fabric from step S1 is immersed in a 75g / L NaOH solution at 90°C for 10 minutes to perform alkali reduction treatment; then, it is treated with dielectric barrier discharge cold plasma at 150W in an O2 atmosphere for 2 minutes to perform surface activation. 10g of *Eupatorium fortunei* extract from Preparation Example 2, 55g of aramid dyeing carrier VKOOT N900 (purchased from UniVOOK Chemical), 2% (owf) cationic blue FGL (purchased from Shanghai Run Biotechnology Co., Ltd.), and 2% (owf) disperse blue 2BLN (purchased from Guangzhou Shuyang Daoerchi E-commerce Co., Ltd.) were dissolved in 1L of deionized water and mixed thoroughly to prepare a dyeing solution. The activated aramid fabric was placed in a dyeing machine, and the dyeing solution was added. The pH was adjusted to 4.2±0.2 using a 0.15mol / L acetate-sodium acetate buffer system (purchased from Jiangsu Maige Biotechnology Co., Ltd.). Subsequently, the system temperature was raised to 130℃ at a rate of 1℃ / min and dyed for 60min. After dyeing, 2.5g of sodium sulfite was added, and the mixture was treated at 75℃ for 12min to remove excess dye, yielding the dyed aramid fabric.

[0089] S3. Immerse the dyed aramid fabric from step S2 into 1L of deionized water containing 25g of the tricyclodecanediethanol bissilane crosslinking agent from Preparation Example 1, adjust the pH to 6.2±0.2, and treat at 75℃ for 12min. After treatment, heat set at 175℃ for 40s. Then, immerse the heat-set dyed aramid fabric into 1L of deionized water containing 25g / L of fluffy amino silicone oil (model RH-NB-8438, purchased from Ningbo Runhe High-tech Materials Technology Co., Ltd.), soak at room temperature for 8min, control the roll-off rate to 75%, and dry at 110℃ until there is no liquid to obtain the pretreated aramid fabric.

[0090] S4. Place the pretreated aramid fabric from step S3 into the plasma treatment chamber, evacuate to 5 Pa, and treat at 200 W for 10 min. Maintain the vacuum, and inject acrylic acid treated by vacuum distillation (temperature 70℃, pressure 5 mmHg) directly into the chamber at a rate of 1.8 mL per gram of fabric. React at 55℃ for 40 min to obtain the modified aramid fabric.

[0091] S5. Immerse the modified aramid fabric from step S4 into 1L of deionized water containing 20g magnesium acetate and 8g zirconium acetate, and pre-bake at 60°C for 3min to obtain the aramid fabric loaded with zirconium magnesium precursor. S6. Take 20g of the extract of *Euphorbia hirta* from Preparation Example 2, 8g of magnesium acetate and 30g of zirconium acetate, mix them together, add 600mL of 100g / L tetraethyl orthosilicate (TEOS) sol-gel reaction solution from Preparation Example 3, 15g of chitosan (pre-dissolved in 150mL of 5% HAc at 45℃), 8g of coumarin-aluminum zirconium hybrid coupling agent from Preparation Example 4 and 1.5g of sodium dodecyl diphenyl ether disulfonate (C12-MADS), adjust the pH to (9.2±0.2) with dilute ammonia, add deionized water to 1L, stir well to obtain a mixture.

[0092] The aramid fabric loaded with zirconium-magnesium precursors in step S5 is immersed in the above mixture and subjected to a two-dip two-roll process (roll pressure of 0.2 MPa, roll rate controlled at 75%), followed by baking at 165°C for 4 min to obtain an aramid fabric loaded with ZrO2 / MgO@SiO2 core-shell nanoparticle coating.

[0093] S7. Lay the aramid fabric loaded with the ZrO2 / MgO@SiO2 core-shell nanoparticle coating from step S6 flat, cover the uncoated surface with a polytetrafluoroethylene film, and use a spray gun (pressure 0.25MPa, spray distance 20cm) at a spray rate of 40mL / m. 2 (Wet condition) The coating layer was uniformly sprayed with a 95% ethanol solution containing 4.5 wt.% hexadecyltrimethoxysilane (HDTMS), and the pH was adjusted to (9.2±0.2) with 26% ammonia. After spraying, the coating was allowed to air dry at room temperature for 8 min, then dried at 110℃ for 8 min, and finally set at 155℃ for 8 min. The aramid fabric loaded with ZrO2 / MgO@SiO2 core-shell nanoparticles after hydrophobic modification was washed three times with deionized water, dried at 80°C until no liquid remained, and then set at 110°C for 4 minutes to obtain the aramid protective fabric.

[0094] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that an equal amount of γ-aminopropyltriethoxysilane (KH-550) is used to replace the coumarin-aluminum zirconium hybrid coupling agent in step S6; the remaining steps are the same as in Example 1.

[0095] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that 30g of *Euphorbia pekinensis* extract in step S6 was replaced with an equal amount of deionized water; the remaining steps were the same as in Example 1, and the final coating was a mixed coating of ZrO2@SiO2 and MgO@SiO2 core-shell nanoparticles.

[0096] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that: 15g of magnesium acetate in step S5 and 10g of magnesium acetate in step S6 are replaced with an equal amount of deionized water; the remaining steps are the same as in Example 1, and the final coating is a coating loaded with ZrO2@SiO2 core-shell nanoparticles.

[0097] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that 5g of zirconium acetate in step S5 and 30g of zirconium acetate in step S6 are replaced with an equal amount of deionized water; the remaining steps are the same as in Example 1, and the final coating is a coating loaded with MgO@SiO2 core-shell nanoparticles.

[0098] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that steps S4 to S6 are omitted; the pre-treated aramid fabric from step S3 is laid flat, the uncoated surface is covered with a polytetrafluoroethylene film, and a spray gun (pressure 0.25 MPa, spray distance 20 cm) is used with a spraying rate of 40 mL / m. 2 (Wet condition) The coating solution is uniformly sprayed onto the surface. The coating solution is a 95% ethanol solution containing 4.5 wt.% hexadecyltrimethoxysilane (HDTMS), and the pH is adjusted to (9.2±0.2) with 26% ammonia. After spraying, the surface is allowed to air dry at room temperature for 8 minutes, then dried at 110℃ for 8 minutes, and finally set at 155℃ for 8 minutes. The pretreated aramid fabric, which has undergone hydrophobic modification, was washed three times with deionized water, dried at 80°C until no liquid remained, and then set at 110°C for 4 minutes to obtain an uncoated aramid protective fabric.

[0099] Test Example 1 Flame retardant performance test To evaluate the flame-retardant properties of the aramid protective fabric of the present invention, the following tests were conducted on the aramid protective fabrics in Examples 1-3 and Comparative Examples 1-5, referring to GB / T 5455-2014 "Determination of Vertical Damage Length, Flame Retardancy and Afterflame Time of Textiles": Five 300mm × 80mm (length × width) samples were cut from the aramid protective fabric of each experimental group, five in the warp and five in the weft. The samples were suspended vertically, the flame height was set to (40±2)mm, the flame was applied for 12s, and the afterflame time (s) and flame retardant time (s) were recorded. The damaged length (mm) was measured, and melting and dripping phenomena were observed.

[0100] Evaluation criteria: Afterflame time is 0s; flame retardant time is 0s; warp damage length ≤ 60mm, weft damage length ≤ 60mm; no melting, no dripping.

[0101] The test results are shown in Table 1 below: Table 1. Test results of flame retardant properties of aramid protective fabrics with different formulations.

[0102] Note: In the table above, the afterflame time of the aramid protective fabric sample in each group is 0s; the flame retardant time is 0s; the warp damage length is ≤60mm, the weft damage length is ≤60mm, there is no melting or dripping, and the result in the judgment column is "qualified"; if at least one of the above five indicators is not met, the result in the judgment column is "unqualified".

[0103] In Examples 1-3, the aramid protective fabric samples showed no melting or dripping; in Comparative Examples 1-5, the aramid protective fabric samples all showed melting and dripping.

[0104] Compared with Examples 1-3, the warp and weft damage lengths of the aramid protective fabric samples in Comparative Examples 1-5 showed significant differences. p <0.05).

[0105] It can be seen from Table 1 above: In Examples 1-3, the afterflame time and flame retardant time of the aramid protective fabric samples were all 0 seconds. The warp damage length was within the range of 48-57 mm, and the weft damage length was within the range of 50-56 mm. Furthermore, all samples showed no melting or dripping, meeting the evaluation criteria and were deemed qualified. This indicates that the aramid protective fabric of the present invention possesses excellent flame retardant properties under different formulation conditions, meeting the requirements for the use of protective fabrics.

[0106] Compared with Examples 1-3, the afterflame time of aramid protective fabric samples in Comparative Example 1 (where γ-aminopropyltriethoxysilane (KH-550) replaced the coumarin-aluminum-zirconium hybrid coupling agent) and Comparative Example 2 (lacking *Euphorbia pekinensis* extract) was 0 s, but the flame retardant time of some samples was 1-2 s. The warp damage length was in the range of 64-70 mm, and the weft damage length was in the range of 65-72 mm. All samples exhibited melting and dripping phenomena, failing to meet the evaluation criteria. This is because the conventional silane coupling agent KH-550 lacks the conjugated aromatic ring structure of coumarin components in its molecular structure, and cannot rearrange to form a stable graphitized carbon layer at high temperatures. It relies solely on the Si-OC covalent bonds to provide limited interfacial bonding force. Simultaneously, the condensation degree of the SiO2 shell is limited, and the coating structure integrity is insufficient, resulting in lower coating adhesion than in Examples 1-3, leading to a significant increase in damage length. p <0.05); while the lack of euphorbia extract results in the coating failing to effectively protect the fiber matrix due to the absence of chemical anchoring groups of coumarin components, causing the interface to delaminate and peel off during combustion.

[0107] In Comparative Example 3 (lacking magnesium acetate) and Comparative Example 4 (lacking zirconium acetate), the afterflame time of the aramid protective fabric samples was 0 seconds. However, the flame retardant time of all samples exceeded 0 seconds, ranging from 1 to 3 seconds. The warp damage length was in the range of 67-78 mm, and the weft damage length was in the range of 69-79 mm. All samples exhibited melting and dripping phenomena, failing to meet the evaluation criteria. Notably, compared to Comparative Example 3, the warp and weft damage lengths of the aramid protective fabric samples in Comparative Example 4 further increased. This confirms that the outer Zr-rich structure is the key and core to achieving high-efficiency flame retardant performance, and its heat insulation and oxygen barrier function is irreplaceable. Although MgO has an effect on promoting char formation in the inner layer, its flame retardant effect is extremely limited without the synergistic effect of the outer ZrO2 layer.

[0108] In the five comparative examples without coating, the afterflame time of the aramid protective fabric samples was 0 seconds, but some samples had a flame retardant time of 1-2 seconds. The warp damage length was the highest at (80±3) mm, and the weft damage length was the highest at (81±4) mm. All samples showed melting and dripping phenomena, failing to meet the evaluation criteria. This indicates that although the aramid protective fabric possesses the intrinsic flame retardant properties of aramid (LOI exceeding 29%, afterflame time of 0 seconds), the fibers still undergo severe cracking and shrinkage under strong fire impact. The intrinsic flame retardancy of the substrate alone cannot simultaneously meet the dual requirements of damage length and anti-dripping properties. ZrO2 is a prerequisite for the functional coating to achieve comprehensive flame retardant protection.

[0109] Test Example 2 Washability and antibacterial performance test To evaluate the wash resistance and antibacterial properties of the aramid protective fabric of the present invention, the aramid protective fabrics in Examples 1-3 and Comparative Examples 1-5 were subjected to an antibacterial performance test after 150 washes. The specific method is as follows: (1) Wash-resistant treatment Referring to GB / T 8629-2017 "Test Procedures for Textiles - Household Washing and Drying", program 4N (Type A standard washing machine, washing temperature 40℃, main wash time 45min, rinsing 3 times, 2min each time, spin drying 5min) was used. 20g of ECE standard detergent was added to each batch along with 1.5kg of accompanying fabric, resulting in a washing liquid volume of 15L. The total sample mass did not exceed 2kg. The washing cycle was 150 times, and drying was done by hanging. After washing, the aramid protective fabric from each experimental group was cut into 5mm×5mm (length×width) pieces, and (0.75±0.05)g of each piece was weighed as an antibacterial test sample, with 5 parallel samples.

[0110] (2) Antibacterial performance test (oscillation method) Referring to GB / T 20944.3-2008 "Evaluation of Antimicrobial Properties of Textiles - Part 3: Shaking Method", the bacterial strain selected was Staphylococcus aureus (… Staphylococcus aureus subsp. golden Rosenbach (ATCC 6538), Escherichia coli ( Escherichia coli (ATCC 8739), Candida albicans ( Candida albicans (ATCC 10231), all purchased from the American Center for Type Culture Collection (ATCC, USA), with a concentration of 5×10⁻⁶. 5 The inoculated bacterial solution was prepared at CFU / mL. The antibacterial test samples obtained in step (1) were immersed in the solution and cultured at 37℃ with shaking for 24 hours. Colony counting was performed according to the standard, and the inhibition rate (%) was calculated according to the following formula: ; Note: AThe number of colonies (CFU / mL) after shaking culture of the blank control sample is indicated. B The number of colonies (CFU / mL) after shaking and culturing the antibacterial test sample is indicated.

[0111] Evaluation criteria: Staphylococcus aureus inhibition rate ≥70%; Escherichia coli inhibition rate ≥70%; Candida albicans inhibition rate ≥60%.

[0112] The test results are shown in Table 2 below: Table 2. Antibacterial performance test results of aramid protective fabrics with different formulations after 150 washes.

[0113] Note: The positive control group used the five uncoated samples of the comparative example as a control. After culturing under the same conditions for 24 hours, the colony count increased by ≥99%, and the bacterial activity was good, proving that the test system was effective. The blank control group contained blank flasks without samples (containing only nutrient broth and inoculated bacterial solution). After culturing under the same conditions for 24 hours, there was no significant colony growth, eliminating the interference of culture medium and environmental contamination on the test results.

[0114] In the table above, if the Staphylococcus aureus inhibition rate of the aramid protective fabric samples in each group is ≥70%, the Escherichia coli inhibition rate is ≥70%, and the Candida albicans inhibition rate is ≥60%, the result in the judgment column is "qualified"; if at least one of the above three indicators is not met, the result in the judgment column is "unqualified".

[0115] Compared with Examples 1-3, the antibacterial rates of Staphylococcus aureus, Escherichia coli, and Candida albicans in the aramid protective fabric samples of Comparative Examples 1-5 were significantly different. p <0.05).

[0116] It can be seen from Table 2 above: In Examples 1-3, the Staphylococcus aureus inhibition rate of the aramid protective fabric samples ranged from 97.6% to 98.7%, the Escherichia coli inhibition rate ranged from 85.9% to 91.6%, and the Candida albicans inhibition rate ranged from 84.2% to 87.5%, all meeting the evaluation criteria and were deemed qualified. This indicates that the aramid protective fabric of the present invention possesses excellent wash-resistant antibacterial properties under different formulation conditions, and the formed coating structure is stable, effectively inhibiting bacterial colonization and growth on the fabric surface even after 150 washes.

[0117] Compared with Examples 1-3, the antibacterial rates of Staphylococcus aureus, Escherichia coli, and Candida albicans in the aramid protective fabric samples of Comparative Example 4 (lacking zirconium acetate) were (89.4±2.2)%, (76.8±2.0)%, and (75.2±2.1)%, respectively. Although all met the evaluation criteria and were deemed qualified, the antibacterial rates of the three bacteria were significantly lower than those in Examples 1-3. p <0.05). This is because the outer layer of ZrO2 also provides physical protection, preventing the washing solution from corroding the inner MgO layer and ensuring the Mg content remains within the MgO layer. 2 + The antibacterial properties are continuously and stably released; however, when magnesium acetate is lacking, MgO is lost more rapidly during repeated washing, leading to a decrease in antibacterial performance. In the three comparative groups lacking magnesium acetate, the antibacterial rates of Staphylococcus aureus, Escherichia coli, and Candida albicans in the aramid protective fabric samples were (27.0±3.1)%, (23.1±3.5)%, and (19.8±3.4)%, respectively, all failing to meet the evaluation criteria and thus deemed unqualified. This confirms that MgO is the core component in this system that achieves highly efficient antibacterial function, which is achieved through the release of Mg... 2+ The antibacterial mechanism that disrupts bacterial cell membranes and interferes with metabolism remains highly effective even after 150 washes; although ZrO2 has a certain antibacterial effect, its antibacterial effect is extremely limited without the synergistic effect of the MgO inner layer.

[0118] In Comparative Example 1, where γ-aminopropyltriethoxysilane (KH-550) replaced the coumarin-aluminum-zirconium hybrid coupling agent, and in Comparative Example 2, which lacked *Euphorbia lathyris* extract, the aramid protective fabric samples exhibited Staphylococcus aureus inhibition rates ranging from 70.1% to 81.5%, Escherichia coli inhibition rates ranging from 66.2% to 68.3%, and Candida albicans inhibition rates ranging from 52.7% to 62.2%. While Staphylococcus aureus met the evaluation criteria, the other two bacterial species did not, and both were deemed unqualified. This is because: conventional silane coupling agent KH-550 lacks active cross-linking groups of coumarin components, and the degree of condensation cross-linking of the SiO2 shell is insufficient, resulting in poor core-shell structure integrity. This leads to decreased coating density and poor wash fastness. After 150 washes, a large amount of coating peels off, and MgO is severely lost, resulting in a significant decrease in antibacterial performance. On the other hand, the lack of peony extract results in the absence of chemical anchoring groups of coumarin components. The coating formed gradually peels off during repeated washing, and at the same time, it loses the synergistic antibacterial effect of the coumarin compounds themselves, leading to a continuous decline in antibacterial performance.

[0119] In the five comparative groups without coating, the antibacterial rates of Staphylococcus aureus, Escherichia coli, and Candida albicans in the aramid protective fabric samples were (7.9±2.3)%, (5.2±2.3)%, and (3.1±1.1)%, respectively, all failing to meet the evaluation criteria and thus deemed unqualified. This indicates that the aramid substrate itself does not possess antibacterial properties, and the fabric's excellent antibacterial performance is entirely derived from the introduction of the functional coating.

[0120] Test Example 3 Anti-mildew performance test To evaluate the mildew resistance of the aramid protective fabric of the present invention, the mildew resistance level of the aramid protective fabrics in Examples 1-3 and Comparative Examples 1-5 was tested in accordance with GB / T 24346-2009 "Evaluation of Mildew Resistance of Textiles". The specific methods are as follows: (1) Preparation of strain and spore suspension The strain selected is Aspergillus niger ( Aspergillus brasiliensis (ATCC 16404), Chaetomium globulus ( Chaetomium globosum Kunze: Fries)(ATCC 6205), green broom mold ( Gliocladium chained Gilman (ATCC 16389) and Penicillium cordiformis ( Penicillium pinophilum (ATCC36839), purchased from the American Type Culture Collection (ATCC, USA).

[0121] The four bacterial strains were inoculated onto potato dextrose agar (PDA) medium and cultured at (28±2)℃ for 12 days. After the spores had fully grown, they were washed with sterile physiological saline containing 0.05% (v / v) Tween-80, and the mycelia were removed by filtration through sterile gauze. The spore suspensions were then collected. The concentration of the spore suspensions for each strain was adjusted to 10 using a hemocytometer. 6 -10 7 CFU / mL, mix the spore suspensions of Aspergillus niger, Chaetomium globosum, Cladosporium virgaureum and Penicillium cordiformis in a volume ratio of 1:1:1:1 to obtain a mixed spore suspension for later use.

[0122] (2) Anti-mildew performance test Five parallel samples were prepared by cutting 50mm × 50mm (length × width) samples from the aramid protective fabrics of each experimental group. The samples were completely immersed in the mixed spore suspension for 10 minutes, then removed and laid flat on sterile moistened filter paper in a sterile petri dish (the filter paper was moistened with sterile water and excess water was drained). The dish was then covered and placed in a constant temperature and humidity incubator at (28±2)℃ and relative humidity >90% for 28 days. The mold growth on the sample surface was observed on days 7, 14, and 28, and the mold growth level was recorded according to the following standards: Level 0: No visible mildew spots on the surface of the specimen with the naked eye; Level 1: The covered area of mildew spots < 10%; Level 2: 10% ≤ the covered area of mildew spots < 30%; Level 3: 30% ≤ the covered area of mildew spots < 60%; Level 4: The covered area of mildew spots ≥ 60%; Evaluation criteria: The mildew grade is Level 0 (i.e., after 28 days of cultivation, there are no visible mildew spots on the surface of the specimen with the naked eye).

[0123] The test results are shown in Table 3 below: Table 3 Mildew-proof performance test results of aramid protective fabrics under different formulations

[0124] Note: The positive control group was compared with the uncoated specimens in 5 groups of comparative examples. After 7 days of cultivation under the same conditions, the mildew grade was Level 4, proving that the test system is effective; the blank control group only contained wet filter paper (without specimens), and no mold growth occurred after 28 days of cultivation, excluding the interference of the medium and environmental self-pollution on the test results.

[0125] In the above table, the mildew grades of the aramid protective fabric specimens in each group at the three time points of the 7th, 14th, and 28th days are all Level 0, and the result in the judgment column is "qualified"; if the mildew grade is at least once Level 1 - 4 at the above three time points, the result in the judgment column is "unqualified".

[0126] As can be seen from Table 3 above: For the aramid protective fabric specimens in Groups 1 - 3 of the examples, the mildew grades at the three time nodes of the 7th, 14th, and 28th days are all (0.0 ± 0.0) level, all meeting the evaluation criteria, and all are judged as qualified. This shows that the aramid protective fabric of the present invention has excellent mildew-proof performance under different formulation conditions, the formed coating structure is stable, and it can still effectively inhibit the colonization and growth of molds on the surface of the fabric under the cultivation conditions of high temperature and high humidity (28 ± 2°C, relative humidity > 90%) for 28 days.

[0127] Compared to Examples 1-3, in Comparative Example 1, where γ-aminopropyltriethoxysilane (KH-550) replaced the coumarin-aluminum-zirconium hybrid coupling agent, the aramid protective fabric sample had a mold growth grade of (0.0±0.0) on day 7, but the mold growth grade increased to (1.0±0.0) on day 14 and further increased to (2.2±0.4) on day 28, failing to meet the evaluation criteria and thus being deemed unqualified. This is because the conventional silane coupling agent KH-550 lacks active crosslinking groups of coumarin components, resulting in a low density of the crosslinked network and poor resistance to mold erosion. The coating formed is gradually destroyed by mold metabolites during long-term cultivation, leading to the loss of anti-mold components. In Comparative Example 2, which lacked *Euphorbia pekinensis* extract, the aramid protective fabric samples showed a mold growth grade of (0.8±0.4) on day 7, but this grade increased to (1.6±0.5) on day 14 and further to (3.2±0.4) on day 28, failing to meet the evaluation criteria and thus being deemed unqualified. This is because the absence of *Euphorbia pekinensis* extract resulted in the lack of chemical anchoring groups for coumarin components. Consequently, the coating and fiber interface delaminated and structurally damaged under mold erosion, and the synergistic antibacterial effect of the coumarin compounds was lost, leading to a continuous deterioration of antifungal performance with prolonged cultivation time. In Comparative Example 3, which lacked magnesium acetate, the aramid protective fabric samples showed a mold growth grade of (1.2±0.4) on day 7, but this grade increased to (2.6±0.9) on day 14 and further to (4.0±0.0) on day 28, failing to meet the evaluation criteria and thus being deemed unqualified. This confirms that MgO is the core component for achieving high-efficiency anti-mildew performance. Although ZrO2 has some anti-mildew activity, its efficiency is far lower than that of MgO, and it cannot inhibit the rapid colonization and growth of mold on the fabric surface. In the four comparative groups lacking zirconium acetate, the mold growth level of the aramid protective fabric samples on days 7 and 14 was (0.0±0.0), but the mold growth level on day 28 was (1.0±0.0), which did not meet the evaluation criteria and was therefore deemed unqualified. This confirms that although MgO is the core anti-mildew component, without the physical protection of the dense ceramic layer on the outside of ZrO2, the coating is easily eroded by mold metabolites in long-term high-humidity environments, resulting in insufficient anti-mildew durability. Specifically, the outer physical protection is jointly provided by the ZrO2 and SiO2 shell layers. The ZrO2 layer, as a dense ceramic layer, blocks the direct penetration of moisture and metabolites, while the SiO2 shell layer provides a second inorganic barrier outside the ZrO2 layer and enhances the overall structural integrity of the coating through its interfacial bonding with the ZrO2 layer. The two work synergistically to effectively prevent moisture and metabolic products from eroding the inner MgO layer, ensuring the integrity of the MgO. 2+ Sustained and stable release is essential; neither can be neglected.

[0128] In the five comparative groups without coating, the aramid protective fabric samples showed a mold growth level of (4.0±0.0) on the 7th day of cultivation, failing to meet the evaluation criteria and thus being deemed unqualified. This indicates that the aramid substrate itself does not possess anti-mold properties; instead, it becomes a favorable substrate for mold growth under high temperature and humidity conditions. The fabric's excellent anti-mold performance is entirely due to the introduction of the functional coating.

[0129] Test Example 4 Functional gradient distribution validation To evaluate the distribution characteristics of magnesium (Mg) and zirconium (Zr) elements in the aramid protective fabric of the present invention along the coating thickness direction, elemental distribution tests were conducted on the aramid protective fabrics of Examples 1-3 and Comparative Examples 1-5. The specific test methods are as follows: (1) Sample preparation The fabric to be tested was cut into 5mm×5mm (length×width) samples, 5 parallel samples were set up, embedded in epoxy resin, and ultrathin sections were obtained by freezing at -120℃ to obtain a flat cross section perpendicular to the fiber direction. The thickness of the sections was controlled at (75±5)nm.

[0130] (2) Testing instruments Line scanning analysis was performed using a field emission scanning electron microscope (SEM-EDS) equipped with an X-ray energy dispersive spectrometer (EDS); in-depth analysis was performed simultaneously using an X-ray photoelectron spectrometer (XPS) in conjunction with argon ion sputtering.

[0131] (3) Test parameters The parameter settings for SEM-EDS line scan are as follows: Accelerating voltage: 15kV; Working distance: 10mm; Scanning mode: Line scan along the direction from the outer surface of the coating to the fiber interface; Scan step size: 50nm; Signal acquisition: Acquire characteristic X-ray signals of Zr and Mg; Data acquisition: 15 seconds for each data point; Quantitative correction: The ZAF correction method was used to quantitatively process the data.

[0132] The parameter settings for XPS deep profiling are as follows: X-ray source: Monochromatic Al Kα X-ray source (hν=1486.6eV); Analytical chamber vacuum level: 5×10 -8 Pa; Sputtered ions: Argon ions (Ar + ); Sputtering energy: 2keV; Sputtering rate: 5 nm / min; Data acquisition interval: Once every 30 s of sputtering. Acquired spectrograms: Full-spectrum scans and high-resolution spectrograms of Zr 3d, Mg 1s, Si 2p, and C 1s.

[0133] (4)Data processing Read the signal intensities (cps) of Zr and Mg in the outer layer region (0 - 30% thickness) and inner layer region (70% - 100% thickness) of the coating in the SEM-EDS line scan respectively. Take 5 scanning points at different positions in each region and record the average signal intensity of each region. Calculate the outer layer Zr / Mg ratio ( R outer ), and the inner layer Zr / Mg ratio ( R inner ). After that, calculate the gradient coefficient ( G ) according to the following formula: ; Evaluation criteria: G ≥ 1.5: Strong gradient distribution (Zr is significantly enriched in the outer layer, and Mg is enriched in the inner layer); 1.0 < G < 1.5: Gradient distribution (there is an obvious concentration gradient); G = (1.0 ± 0.1): Uniform distribution (no obvious gradient).

[0134] The test results are shown in Table 4 below: Table 4 Gradient coefficient test results of aramid protective fabrics under different formulations

[0135] As can be seen from Table 4 above: For the aramid protective fabric specimens in Examples 1 - 3 groups, the gradient coefficients are within the range of 1.97 - 2.62, all ≥ 1.5, and are determined to have a strong gradient distribution. This confirms that through the gradient impregnation process of pre-impregnating with a Mg-rich solution and impregnating with a Zr-rich solution in the present invention, combined with the differential thermal diffusion behavior of Mg 2+ and Zr 4+ during the baking process, a functional gradient coating structure with Zr-rich outer layer and Mg-rich inner layer can be effectively constructed under different formulation conditions.

[0136] Compared with Examples 1 - 3 groups, in Comparative Example 1 group where γ-aminopropyltriethoxysilane (KH-550) is used to replace the coumarin-aluminum zirconium hybrid coupling agent, the gradient coefficient of the aramid protective fabric specimen is (1.25 ± 0.12), satisfying 1.0 < G < 1.5, and is determined to have a gradient distribution. This is because the conventional silane coupling agent KH-550 lacks the aromatic ring structure and multidentate coordination ability of the coumarin component, and although the amino group (-NH2) in its molecular structure can react with Zr 4+Coordination occurs, but the coordination site is singular and the coordination stability constant is low, preventing the formation of a stable multidentate chelate structure like the phenolic hydroxyl groups of coumarin components. Insufficient anchoring leads to Zr 4+ During the baking process, TEOS migrates into the inner layer, while the enrichment level in the outer layer decreases. Simultaneously, although the SiO2 shell formed by the condensation of TEOS during baking provides physical coating, it does not possess coordination-driven functionality. 4+ The gradient migration still requires chemical mediation by coumarin polydentate ligands. In contrast, the gradient coefficient of the aramid protective fabric samples in Comparative Example 2, which lacked *Euphorbia pekinensis* extract, was (1.01±0.07), and was judged to be uniformly distributed. This is because the coumarin components in *Euphorbia pekinensis* extract react with Zr via phenolic hydroxyl groups. 4+ Coordination complexation, delaying Zr during baking 4+ Thermal diffusion is the key medium for achieving a gradient distribution of Zr-rich outer layers and Mg-rich inner layers; when Zr is absent... 4+ Free diffusion into the inner layer leads to the complete loss of the concentration gradient. This indicates a synergistic effect between the coordination anchoring of coumarin components and the physical coating of the SiO2 shell, with the former driving Zr... 4+ Selective migration to the outer layer of the fiber, which condenses and solidifies in the later stage of baking, provides spatial confinement and physical protection for the already formed gradient distribution. Together, they ensure the effective construction and stable maintenance of the functional gradient structure.

[0137] In comparative example 3 (lacking magnesium acetate), comparative example 4 (lacking zirconium acetate), and comparative example 5 (without coating), the aramid protective fabric samples could not form an effective functional gradient coating because the characteristic signals of Mg and / or Zr could not be detected.

[0138] Test Example 5 Physical performance testing To evaluate the physical properties of the aramid protective fabric of the present invention, the unit area mass, breaking strength (warp and weft), and tearing strength (warp and weft) of the aramid protective fabrics in Examples 1-3 and Comparative Examples 1-5 were tested. The specific test methods are as follows: (1) Mass per unit area test Referring to GB / T 4669-2008 "Textiles - Determination of Mass per Unit Length and Mass per Unit Area of ​​Fabrics", 10cm × 10cm (length × width) samples were cut from the aramid protective fabrics of each experimental group, 5 samples each in the warp and weft directions, avoiding selvage and obvious defects. The samples were conditioned under standard atmospheric conditions for 24 hours. The mass of each sample was weighed, accurate to 0.001g. The mass per unit area was calculated using the following formula: ; Note: The sample area is 0.01m². 2 .

[0139] Calculate the arithmetic mean of each sample.

[0140] Evaluation criteria: Mass per unit area ≤ 210g / m² 2 .

[0141] (2) Fracture strength test (meridian and zonal) Referring to GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength (Strip Method)", 500mm × 50mm (length × width) samples were cut from the aramid protective fabrics of each experimental group, with 5 samples each in the warp and weft directions, evenly distributed, 200mm from the selvage. After conditioning the samples under standard atmospheric conditions for 24 hours, the clamping distance was set to 200mm, and the tensile speed was 100mm / min. Both ends of the sample were clamped into the upper and lower clamps respectively, ensuring no skewing. The sample was stretched until it broke, and the maximum breaking strength (N) was recorded.

[0142] Evaluation criteria: Meridional breaking strength ≥ 1100 N, latitudinal breaking strength ≥ 1100 N.

[0143] (3) Tear strength test (warp and weft) Referring to GB / T 3917.2-2009 "Textiles - Tear Properties of Fabrics - Part 2: Determination of Tear Strength of Trousers Specimens (Single Seam)," 200mm × 50mm (length × width) specimens were cut from the aramid protective fabrics of each experimental group, five in the warp and five in the weft directions, 200mm from the selvage. A 150mm slit was cut along the length of the specimen at its center to form two trouser legs. After conditioning the specimens under standard atmospheric conditions for 24 hours, the clamping distance was set to 100mm, and the tensile speed to 100mm / min. The two trouser legs of the specimen were clamped into the upper and lower clamps respectively, with the slit line located in the center of the clamps. The instrument was started, and the specimen was stretched until it was completely torn, and the tear strength (N) was recorded.

[0144] Evaluation criteria: Warp tear strength ≥ 270N, weft tear strength ≥ 200N.

[0145] The test results are shown in Table 5 below, expressed as mean ± standard deviation: Table 5. Test results of physical properties of aramid protective fabrics with different formulations.

[0146] Note: The unit area mass of the aramid protective fabric samples in each group in the table above is ≤210g / m². 2 If the longitudinal breaking strength is ≥1100N, the latitudinal breaking strength is ≥1100N, the longitudinal tear strength is ≥270N, and the latitudinal tear strength is ≥200N, the result in the judgment column is "qualified"; if at least one of the above five indicators is not met, the result in the judgment column is "unqualified".

[0147] It can be seen from Table 5 above: The unit area mass of the aramid protective fabric samples in the five comparative examples without coating was (200.2±2.1) g / m². 2 The warp breaking strength is (1160±23) N, the weft breaking strength is (1148±26) N, the warp tear strength is (295±17) N, and the weft tear strength is (232±14) N, all of which meet the evaluation criteria. This indicates that the aramid substrate itself has an inherently excellent mechanical property.

[0148] Compared with Comparative Example 5, the unit area mass of the aramid protective fabric samples in Examples 1-3 was between 204.6 and 207.7 g / m². 2 Within the specified range, the warp breaking strength is in the range of 1171-1201 N, the weft breaking strength is in the range of 1160-1181 N, the warp tear strength is in the range of 313-331 N, and the weft tear strength is in the range of 241-258 N, all of which are superior to the five comparative examples and all meet the evaluation criteria. This confirms that by constructing a coumarin-aluminum zirconium hybrid coupling agent crosslinking network on the aramid surface and loading a ZrO2 / MgO@SiO2 core-shell nanoparticle coating, the present invention can achieve effective mechanical reinforcement compensation of the fiber substrate through uniform coating and interfacial bonding while maintaining the advantage of lightweight.

[0149] Compared with Comparative Example 5, the unit area mass of the aramid protective fabric samples in Comparative Example 1 (where γ-aminopropyltriethoxysilane (KH-550) replaced the coumarin-aluminum-zirconium hybrid coupling agent), Comparative Example 2 (lacking *Euphorbia pekinensis* extract), Comparative Example 3 (lacking magnesium acetate), and Comparative Example 4 (lacking zirconium acetate) ranged from 201.5 to 203.2 g / m². 2Within the specified range, the warp breaking strength was between 1084-1098 N, the weft breaking strength was between 1071-1099 N, the warp tear strength was between 248-268 N, and the weft tear strength was between 173-194 N, all lower than the five comparative groups, and none met the evaluation criteria. This is because: the conventional silane coupling agent KH-550 lacks the aromatic ring structure and multidentate coordination ability of coumarin components, and therefore cannot form a strong π-π stacking and chelate anchoring with the aramid surface, resulting in weak interfacial bonding and difficulty in forming an effective cross-linked network; the lack of *Euphorbia milii* extract leads to insufficient interfacial bonding strength between the coating and the fiber due to the loss of chemical anchoring by coumarin components; and the single coating (containing only ZrO2@SiO2 or only MgO@SiO2) results in an incomplete hybrid network structure and increased defects due to the single inorganic component. All of these factors prevent the coating from forming a continuous and dense structural reinforcement layer on the fiber surface. This is mainly reflected in the insufficient integrity and density of the SiO2 shell. The SiO2 network formed by the condensation of the TEOS sol-gel reaction solution not only coats the ZrO2 / MgO core to form a core-shell structure, but also provides additional load-bearing capacity to the coating through its own rigid inorganic framework. When the SiO2 network structure is incomplete (such as in Comparative Examples 3 and 4, which contain a single coating), the interface defects between the inorganic and organic phases in the coating increase, the stress transmission path is interrupted, and the mechanical reinforcement effect is lost. Therefore, the stress transmission efficiency is low, and cracks easily initiate and rapidly propagate at the defects under load, leading to premature fracture during tensile and tearing processes, and a significant reduction in physical properties.

[0150] Test Example 6 Durability color fastness test To evaluate the durable colorfastness of the aramid protective fabric of the present invention, the colorfastness to washing staining and the colorfastness to water rubbing of the aramid protective fabrics in Examples 1-3 and Comparative Examples 1-5 were tested. The specific test methods are as follows: (1) Color fastness to washing and staining test Referring to method C(3) of GB / T 3921-2008 "Tests for Color Fastness of Textiles - Color Fastness to Washing", 40mm×100mm (length×width) samples were cut from the aramid protective fabrics of each experimental group, and 5 parallel samples were set up. The samples were sandwiched between cotton and wool monofiber lining fabrics and sewn along the short side to form composite samples. The composite samples were placed in a container and soap solution preheated to 60℃ (containing 5g soap and 2g anhydrous sodium carbonate per liter of grade III water) was added, with a bath ratio of 50:1. Following method C(3) without adding stainless steel beads, the container was covered and treated at 60℃ for 30min. After washing, the composite samples were taken out, washed twice with grade III water, rinsed clean in running water, squeezed out excess water, spread out, and hung to dry at (55±2)℃. The staining grades of cotton and wool linings were assessed according to the gray scale of GB / T251-2008, and the grade of the heavier staining was taken as the staining grade of the sample.

[0151] Evaluation criteria: Staining grade ≥ 4.

[0152] (2) Water rubbing color fastness test Referring to GB / T 3920-2008 "Textiles - Tests for Color Fastness to Rubbing", 50mm × 140mm (length × width) samples were cut from aramid protective fabrics in each experimental group, and five parallel samples were set up. The samples were conditioned for 24 hours under standard atmospheric conditions. A rubbing fastness tester was used, with a cylindrical rubbing head of (16±0.2)mm in diameter, applying a downward vertical pressure of (9±0.2)N, a reciprocating stroke of (104±5)mm, and a rubbing speed of 60 times / min.

[0153] Dry friction: Fix a dry standard friction cloth (compliant with GB / T 7568.2, cut into 50mm×50mm pieces) onto the friction head and rub back and forth 10 times.

[0154] Wet friction: Soak the standard friction cloth in distilled water, roll it to a moisture content of (98±2)%, complete the friction within 3 minutes, and repeat the friction 10 times.

[0155] The staining grade of dry and wet friction cloths was assessed according to the gray scale for staining in GB / T 251-2008.

[0156] Evaluation criteria: Dry friction grade ≥ 4; Wet friction grade ≥ 4.

[0157] The test results are shown in Table 6 below, expressed as mean ± standard deviation: Table 6. Test results of color fastness performance of aramid protective fabrics with different formulations.

[0158] Note: For the aramid protective fabric samples in each group in the above table, the staining grade ≥ 4, the dry rubbing grade ≥ 4, and the wet rubbing grade ≥ 4, and the result in the judgment column is "qualified"; if at least one of the above three indicators is not met, the result in the judgment column is "unqualified".

[0159] As can be seen from Table 6 above: In the aramid protective fabric samples of the Examples 1-3 groups, the staining grade is within the range of 4-5, the dry rubbing grade is within the range of 4-5, and the wet rubbing grade is within the range of 4-5, all meeting the evaluation criteria and the judgments are all qualified. This shows that by constructing a coumarin-aluminum zirconium hybrid coupling agent cross-linked network on the surface of aramid and loading a ZrO2 / MgO@SiO2 core-shell nanoparticle coating in the present invention, due to the dense cross-linked network and the strong binding between the inorganic particles and the fiber interface, it can still effectively block the transfer of dyes to the lining under the conditions of soaping and wet rubbing, endowing the fabric with excellent hydrolysis stability and interfacial adhesion durability.

[0160] Compared with the Examples 1-3 groups, in the Comparative Example 1 group where γ-aminopropyltriethoxysilane (KH-550) is used to replace the coumarin-aluminum zirconium hybrid coupling agent and the Comparative Example 2 group lacking Philadelphus pekinensis extract, the staining grade of the aramid protective fabric samples is within the range of 2-3, the dry rubbing grade is within the range of 2-3, and the wet rubbing grade is within the range of 2-3, all not meeting the evaluation criteria and the judgments are all unqualified. This is because: the conventional silane coupling agent KH-550 lacks the conjugated aromatic ring structure and multidentate coordination ability of coumarin components, and cannot form strong π-π stacking and efficient chelating anchoring with the aramid surface. Only relying on a single Si-O-C covalent bond to provide interfacial binding, the cross-linked network density is low, the washability is poor, and the coating is easy to peel off; the lack of Philadelphus pekinensis extract directly weakens the chemical anchoring effect and interfacial dispersion stability between the coating and the fiber, making the coating more likely to be damaged and peeled off during mechanical friction and soaping. After the dyes lose physical shielding and chemical fixation, a large amount of desorption occurs, and the color fastness further decreases.

[0161] In Comparative Example 3 (lacking magnesium acetate) and Comparative Example 4 (lacking zirconium acetate), the staining grade of the aramid protective fabric samples was in the range of 3-4, the dry friction grade was in the range of 3, and the wet friction grade was in the range of 2-3, all failing to meet the evaluation criteria and thus being deemed unqualified. This is because single coatings (containing only ZrO2@SiO2 or only MgO@SiO2) lack complementary inorganic networks, making it impossible to construct a complete functional gradient structure with an outer layer rich in Zr and an inner layer rich in Mg, resulting in insufficient overall integrity and density of the coating. This is mainly closely related to the degree of condensation crosslinking of the SiO2 shell. As the outer barrier of the core-shell structure, the degree of condensation crosslinking of the SiO2 shell directly determines the density and barrier performance of the coating. When the ratio of SiO2 precursor (TEOS sol-gel reaction solution) to Zr / Mg precursor (zirconia / magnesium acetate) is unbalanced (such as in Comparative Example 3 and Comparative Example 4 containing single coatings), the SiO2 network cannot form a continuous and complete coating layer, leading to increased structural defects and decreased density in the coating. The structural defects create weak channels for dye desorption, which not only have limited physical barrier effects, but also cause preferential desorption of dye around the defects, resulting in lower color fastness than in Examples 1-3 of the complete gradient coating.

[0162] In the five comparative groups without coating, the aramid protective fabric samples had a staining grade of 2-3, a dry rubbing grade of 2, and a wet rubbing grade of 1-2, all of which failed to meet the evaluation criteria and were the worst in color fastness among all experimental groups, thus all were deemed unqualified. This confirms that aramid fabrics without coating protection lack both a physical barrier to prevent external erosion and chemical bonding anchoring, making them extremely prone to desorption and detachment during washing and rubbing.

[0163] Test Example 7 Other functional tests To evaluate the wearing comfort and functionality of the aramid protective fabric of the present invention, the unidirectional moisture wicking properties and softness (flexural stiffness) of the aramid protective fabrics in Examples 1-3 and Comparative Examples 1-5 were tested. The specific test methods are as follows: (1) One-way moisture conduction performance test Referring to GB / T 21655.2-2019 "Evaluation of the Moisture Absorption and Quick-Drying Properties of Textiles - Part 2: Dynamic Moisture Transfer Method", 90mm × 90mm (length × width) samples were cut from the aramid protective fabrics of each experimental group and conditioned for 24 hours under standard atmospheric conditions. The samples were placed flat between the instrument's sensors, with the side closest to the skin during actual wear as the immersion surface, facing the direction of the test liquid drop. The instrument was started, and (0.22 ± 0.01) g of test liquid was dropped onto the immersion surface of the fabric. The change in moisture content within 120 seconds was immediately recorded, with a data acquisition frequency of no less than 10 Hz. After the test, the instrument automatically calculated the unidirectional transfer index. After each test, the residual liquid on the sensor plate was absorbed with absorbent paper, allowed to stand for 80 seconds, and the test was repeated only after ensuring no residue remained.

[0164] One-way transmission index is rated according to the following levels: Level 1: <100; Level 2: 100-299; Level 3: 300-499; Level 4: 500-699; Level 5: ≥700.

[0165] Evaluation criteria: Single-item transmission index level ≥ 3 (i.e., index ≥ 300).

[0166] (2) Flexibility (bending stiffness) test Referring to GB / T 18318.1-2009 "Determination of Bending Properties of Textiles - Part 1: Inclined Plane Method", 200mm × 25mm (length × width) samples were cut from the aramid protective fabrics of each experimental group, 5 samples each in the warp and weft directions, with the samples 120mm from the selvage. The samples were placed flat on the testing platform, one end aligned with the scale line, and the other end extended freely. The sliding plate was slowly pushed to tilt the sample with the platform until the free end contacted the inclined plane, and the bending length was read. The bending stiffness was calculated using the following formula: ; Evaluation criteria: warp bending stiffness ≤ 15 cN·cm, weft bending stiffness ≤ 15 cN·cm.

[0167] The test results are shown in Table 7 below, expressed as mean ± standard deviation: Table 7. Test results of unidirectional moisture wicking and softness (flexural stiffness) of aramid protective fabrics with different formulations.

[0168] Note: In the table above, if the single-transfer index level of the aramid protective fabric sample in each group is ≥3, the warp bending stiffness is ≤15cN·cm, and the weft bending stiffness is ≤15cN·cm, the result in the judgment column is "qualified"; if at least one of the above three indicators is not met, the result in the judgment column is "unqualified".

[0169] It can be seen from Table 7 above: In the five comparative examples without coating, the aramid protective fabric samples had a single-element transfer index of (3.2±0.4), a warp bending stiffness of (7.8±1.2) cN·cm, and a weft bending stiffness of (7.4±0.8) cN·cm, all meeting the evaluation criteria and were deemed qualified. This indicates that the aramid substrate itself possesses inherently good softness and a certain degree of moisture transfer capability.

[0170] Compared with Comparative Example 5, the aramid protective fabric samples in Examples 1-3 had a single-phase transfer index level of 3.6-4.8, which was better than Comparative Example 5. Their warp bending stiffness was in the range of 9.6-11.6 cN·cm, and their weft bending stiffness was in the range of 9.1-11.2 cN·cm. Although both were higher than Comparative Example 5, they still met the evaluation criteria and were deemed qualified. This result confirms that the present invention, by constructing a coumarin-aluminum-zirconium hybrid coupling agent crosslinking network on the aramid surface and loading a ZrO2 / MgO@SiO2 core-shell nanoparticle coating, can effectively avoid rigid agglomeration while introducing functional micro / nano structures, achieving a synergistic unity of excellent unidirectional moisture wicking and good softness.

[0171] Compared with Comparative Example 5, the aramid protective fabric samples in Comparative Example 1 (where γ-aminopropyltriethoxysilane (KH-550) replaced the coumarin-aluminum-zirconium hybrid coupling agent), Comparative Example 2 (lacking *Euphorbia pekinensis* extract), Comparative Example 3 (lacking magnesium acetate), and Comparative Example 4 (lacking zirconium acetate) had single-phase transfer index levels ranging from 1.6 to 2.8, warp bending stiffness ranging from 14.4 to 17.7 cN·cm, and weft bending stiffness ranging from 14.1 to 18.1 cN·cm. Although some indicators of some samples met the evaluation criteria, it was still impossible to guarantee that all three indicators met the evaluation criteria. Therefore, all samples were judged to be unqualified. This is because: conventional silane coupling agent KH-550 lacks the conjugated aromatic ring structure and multidentate coordination ability of coumarin components, making it difficult to form a strong π-π stack and chelate anchoring on the aramid surface, resulting in insufficient coating adhesion and uneven distribution; the absence of *Euphorbia pekinensis* extract leads to the loss of key interfacial anchoring and dispersion stabilization functions, resulting in a significant decrease in coating uniformity; single coatings (containing only ZrO2@SiO2 or only MgO@SiO2) suffer from insufficient sol-gel precursors, resulting in low inorganic network crosslinking density and a non-dense coating structure. Among these factors, the dispersion stability of the TEOS sol-gel reaction solution (SiO2 precursor) is particularly critical. The degree of condensation and uneven particle size distribution of TEOS sol in the mixture directly affect the final arrangement of core-shell particles on the fiber surface. When the ratio of SiO2 precursor (TEOS sol) to Zr / Mg precursor (zirconium acetate / magnesium) is improper or the cross-linking network is incomplete (such as in Comparative Example 3 and Comparative Example 4 with a single coating), the sol particles are prone to agglomeration, resulting in non-uniform deposition of the subsequently generated core-shell particles on the fiber surface. On the one hand, this blocks the microchannels between fibers used for the directional transport of liquid water. On the other hand, the rigid stress concentration points generated by agglomeration significantly degrade the fabric's hand feel, thus failing to achieve both efficient moisture-wicking function and soft and comfortable wear.

[0172] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An intrinsically flame-retardant, high-strength aramid protective fabric, characterized in that, The protective fabric includes a first thin layer and a second thin layer; the second thin layer is loaded on the outer surface of the first thin layer. The first thin layer is a single-layer fabric structure, which is divided into an outer layer region and an inner layer region from the outside to the inside in the fabric thickness direction. The outer layer region and the inner layer region are connected alternately by face-to-face bonding or double-sided weave, forming a number of microchannels for unidirectional moisture conduction between the outer layer region and the inner layer region. The second thin layer is a zirconium magnesium@SiO2 core-shell nanoparticle coating generated in situ through the mediated formation of eupatorium extract; The zirconium magnesium@SiO2 core-shell nanoparticle coating is anchored to the surface of the first thin layer; In the coating, magnesium and zirconium elements form a functional gradient distribution along the thickness direction of the first thin layer. The mass concentration of zirconium element in the outer layer region of the coating is higher than that in the inner layer region, and the mass concentration of magnesium element in the inner layer region is higher than that in the outer layer region.

2. The aramid protective fabric as described in claim 1, characterized in that, The zirconium-magnesium@SiO2 core-shell nanoparticle coating is anchored to the surface of the first thin layer through a cross-linked network formed by coumarin-aluminum-zirconium hybrid coupling agent and chitosan.

3. The aramid protective fabric as described in claim 2, characterized in that, The coumarin-aluminum zirconium hybrid coupling agent is prepared by coordination reaction of *Euphorbia pekinensis* extract and aluminum zirconate coupling agent.

4. The aramid protective fabric as described in claim 1, characterized in that, The aramid is para-aramid.

5. A method for preparing an intrinsically flame-retardant, high-strength aramid protective fabric, characterized in that, Includes the following steps: S1. Aramid fibers are woven by joining the inner and outer sides or by double-sided weaving to form an aramid fabric with unidirectional moisture-wicking microchannels. S2. After the aramid fabric in step S1 is subjected to alkali reduction treatment and plasma surface activation, it is placed in a dye bath containing aramid extract, aramid dyeing carrier, cationic dye, disperse dye and acetate-sodium acetate buffer system for dyeing treatment to obtain dyed aramid fabric. S3. The dyed aramid fabric from step S2 is subjected to cross-linking fixation, heat setting and softening finishing, and dried to obtain the pretreated aramid fabric. S4. The pretreated aramid fabric in step S3 is subjected to plasma activation and acrylic acid grafting to introduce a polyacrylic acid graft layer to obtain a modified aramid fabric. S5. Immerse the modified aramid fabric from step S4 in deionized water containing magnesium salt and zirconium salt, and pre-bake at 55-65℃ for 2-4 minutes to obtain the aramid fabric loaded with zirconium magnesium precursor. S6. The aramid fabric loaded with zirconium magnesium precursor in step S5 is immersed in a mixture containing euphorbia extract, magnesium salt, zirconium salt, SiO2 precursor, chitosan, coumarin-aluminum zirconium hybrid coupling agent and auxiliaries. After padding and baking, an aramid fabric loaded with zirconium magnesium@SiO2 core-shell nanoparticle coating is obtained. S7. The aramid fabric loaded with zirconium magnesium@SiO2 core-shell nanoparticle coating in step S6 is subjected to one-sided hydrophobic modification, and then washed, dried and heat-set to obtain aramid protective fabric.

6. The preparation method according to claim 5, characterized in that, The preparation method of the coumarin-aluminum-zirconium hybrid coupling agent in step S6 is as follows: (1) Take the extract of the flower of the flower, and after chromatography, elution, collection of the elution fraction, concentration under reduced pressure, and freeze drying, the coumarin components are obtained; (2) After mixing the coumarin components obtained in step (1) with anhydrous N,N-dimethylformamide at a ratio of 1g:(10-20)mL, triethylamine is added and the mixture is heated to 70°C under nitrogen protection. Then, aluminum zirconate coupling agent is slowly added dropwise and the mixture is stirred and refluxed under nitrogen protection at 70°C for 3-4 hours to form a coumarin-aluminum zirconium hybrid complex. (3) After the reaction is completed, the mixture is concentrated under reduced pressure and washed 2-3 times with anhydrous ethanol and dried under vacuum to obtain the coumarin-aluminum zirconium hybrid coupling agent.

7. The preparation method according to claim 6, characterized in that, The mass ratio of coumarin components to aluminum zirconate coupling agent is 1:(2-4); the ratio of triethylamine to coumarin components is 1g:(0.4-0.6)mL.

8. The preparation method according to claim 5, characterized in that: In step S5: the molar ratio of magnesium salt to zirconium salt is (9-12):1; In step S6: the mass ratio of the addition of *Eupatorium fortunei* extract to magnesium salt is (2-3):1; the molar ratio of magnesium salt to zirconium salt is (0.5-1.3):

1.

9. The preparation method according to claim 5, characterized in that: In step S5: the concentration of the magnesium salt is 15-25 g / L; the concentration of the zirconium salt is 5-10 g / L; In step S6: the concentration of the *Eupatorium fortunei* extract is 10-30 g / L; the concentration of the magnesium salt is 5-10 g / L; the concentration of the zirconium salt is 25-35 g / L; the amount of the SiO2 precursor added is 50-80 g / L; the amount of chitosan added is 10-20 g / L; the amount of the coumarin-aluminum-zirconium hybrid coupling agent added is 5-10 g / L; and the amount of the auxiliary agent added is 0.5-2 g / L.

10. The application of the aramid protective fabric prepared by the preparation method according to any one of claims 5-9 in the preparation of personal protective equipment.

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