Preparation method of flame-retardant and antibacterial bifunctional polyester textile fabric

Abstract

The application relates to the technical field of functional polyester textiles, and discloses a preparation method of a flame-retardant and antibacterial dual-functional polyester textile fabric. First, zinc source and copper source are used to prepare zinc-copper composite metal oxide nanoparticles, which are coated with dopamine and modified by phosphorylation, and then are compounded with a flame-retardant oligomer containing phosphorus, nitrogen and siloxane structure to obtain a metal nanoparticle catalytic activation type phosphorus-nitrogen-silicon flame-retardant and antibacterial agent; then the flame-retardant and antibacterial agent is melt-blended with polyester carrier resin, an interfacial compatibilizer and a processing aid to prepare a functional masterbatch, and is mixed with polyester chips to prepare the fabric through drying, melt spinning, drafting, winding, weaving and heat setting. The metal active sites in the flame-retardant and antibacterial agent can promote the flame-retardant oligomer to dehydrate, condense and form carbon in advance, a phosphorus-silicon carbonization protective layer is formed, the zinc-copper component simultaneously provides antibacterial action, and the functional components are distributed in the fibers in an embedded mode and are not easy to be washed off, so that the obtained fabric has high flame retardance, antibacterial durability and processing stability.

Description

Technical Field

[0001] This invention relates to the field of textiles, and in particular to a method for preparing a flame-retardant and antibacterial dual-functional polyester textile fabric. Background Technology

[0002] Polyester fiber is a synthetic fiber with polyethylene terephthalate as its main component. It possesses advantages such as high strength, good dimensional stability, good abrasion resistance, ease of processing, and low cost, and is widely used in clothing, home textiles, decorative fabrics, vehicle interiors, public textiles, and protective textiles. With the continuous expansion of textile applications, especially in public health, transportation interiors, hotel furnishings, medical auxiliary materials, and protective clothing, single mechanical and appearance properties are no longer sufficient to meet usage requirements. Textiles possessing flame-retardant, antibacterial, durable, and processable properties are gradually becoming an important development direction.

[0003] However, ordinary polyester materials are inherently flammable polymers with a low limiting oxygen index, making them prone to melting, shrinkage, dripping, and continuous combustion when exposed to fire or high-temperature heat sources. Polyester readily produces flammable pyrolysis products during heating and has a weak char-forming ability, making it difficult to form a continuous, dense, and stable char protective layer after combustion. Therefore, it is ineffective at blocking the transfer of heat, oxygen, and flammable gases. Especially in woven form, polyester fabrics have a large specific surface area and air contact area, resulting in rapid combustion propagation. Molten droplets can also ignite surrounding combustibles, increasing the risk of secondary combustion. Therefore, improving the flame-retardant properties of polyester textiles is of great significance for expanding their application in public safety and protection fields.

[0004] Existing methods for flame-retardant modification of polyester mainly include flame-retardant copolymerization, flame-retardant blend spinning, and flame-retardant finishing. Flame-retardant copolymerization typically involves introducing phosphorus-containing flame-retardant monomers during the polyester synthesis stage, allowing the flame-retardant structure to enter the polyester molecular chain. This results in good flame-retardant durability, but it significantly impacts the polymerization process, chip quality, spinning window, and product cost, making industrial switching difficult. Flame-retardant finishing usually involves attaching flame retardants to the fabric surface through padding, coating, or impregnation. This process is relatively simple, but the flame retardants are mainly distributed on the fiber surface and are easily migrated and lost during washing, friction, or long-term use, potentially affecting the fabric's feel, breathability, and wash resistance. Flame-retardant blend spinning involves adding flame retardants to the polyester melt in masterbatch or powder form to prepare functional fibers. It has advantages such as good process adaptability and stable distribution of functional components, but it requires high standards for the thermal stability, dispersibility, compatibility, and spinning processing adaptability of the flame retardants.

[0005] Traditional flame retardants used in polyester are mainly phosphorus-containing flame retardants, phosphorus-nitrogen intumescent flame retardants, inorganic flame retardants, or their compound systems. Phosphorus-containing structures can promote acid source generation and dehydration carbonization during heating, nitrogen-containing structures can assist in expansion insulation and dilution of combustible gases, and inorganic components can improve the stability of the char layer. However, in polyester systems, single phosphorus-containing or phosphorus-nitrogen flame retardants still have problems such as high flame retardant dosage, high char formation activation temperature, insufficient char layer continuity, and limited drip suppression effect. Especially before the severe thermal decomposition of polyester, if the flame retardant system cannot form an effective char protective layer in time, a large amount of combustible decomposition products will be released, making it difficult to fully exert the subsequent flame retardant effect. Therefore, how to activate the flame retardant in advance at a lower temperature range and promote char formation protection in the early stages of polyester combustion is an important technical problem for improving the flame retardant efficiency of polyester.

[0006] On the other hand, textiles easily absorb human sweat, sebum, dust, and environmental pollutants during use, becoming carriers for bacterial growth and spread. Especially in applications such as public places, medical care, home textiles, and intimate apparel, antibacterial properties have become one of the important performance characteristics of functional polyester fabrics. Existing antibacterial polyester fabrics typically use silver-based, zinc-based, or copper-based inorganic antibacterial agents, or organic antibacterial agents such as quaternary ammonium salts, guanidine salts, and chitosan for finishing or blending modification. Among these, inorganic antibacterial agents have advantages such as good heat resistance, a broad antibacterial spectrum, and suitability for melt processing; however, they are prone to agglomeration in the polyester matrix, resulting in weak interfacial bonding with the polyester matrix. Long-term use or washing can lead to migration, precipitation, and decreased antibacterial durability. If antibacterial properties are only imparted through finishing processes, the antibacterial components are more likely to detach from the fiber surface, making it difficult to simultaneously achieve washability and long-term stability.

[0007] To simultaneously impart flame retardant and antibacterial properties to polyester fabrics, existing technologies include adding both flame retardants and antibacterial agents to the fibers or fabric. However, these solutions are often simply a superposition of functional components, with the flame retardant responsible for flame retardancy and the antibacterial agent for antibacterial properties, lacking a clear structural relationship and synergistic effect between the two. Simple compounding systems are prone to the following problems: First, the different compatibility of flame retardants and antibacterial agents in the polyester melt can easily lead to uneven dispersion of functional components, powder agglomeration, and increased spinning and filtration pressure; second, if antibacterial particles exist only as inert fillers, they cannot participate in the flame retardant charring process, thus having limited impact on flame retardant efficiency; third, the migration or precipitation of flame retardants and antibacterial agents can result in insufficient wash-resistant flame retardant and wash-resistant antibacterial properties; fourth, to simultaneously meet the requirements of flame retardancy and antibacterial properties, it is often necessary to increase the total amount of functional components added, thereby affecting the mechanical properties, spinnability, and fabric feel of the polyester fibers.

[0008] In recent years, metal oxide nanoparticles have been used in polymer flame retardant or antibacterial modification due to their high specific surface area, surface active sites, and certain antibacterial activity. Metal oxides such as zinc and copper not only provide antibacterial effects but may also influence acid source release, dehydration condensation, char layer formation, and inorganic framework construction during polymer thermal decomposition. However, if metal oxide nanoparticles are directly added to polyester or flame retardant systems, their high surface energy makes them prone to aggregation, and the lack of stable interfacial bonding between them and the organic flame retardant and polyester matrix makes it difficult for the metal active sites to effectively approach the flame retardant structure, thus hindering the full catalytic char formation effect. Furthermore, unmodified metal nanoparticles may cause filter clogging, yarn breakage, and decreased fiber performance during melt spinning.

[0009] Therefore, existing flame-retardant and antibacterial polyester fabrics still need to solve the following technical problems: how to construct a functional system that has both flame-retardant charring ability and antibacterial activity; how to make antibacterial metal nanoparticles no longer just ordinary antibacterial fillers, but able to participate in the thermal activation and charring process of flame retardants; how to improve the interfacial bonding between metal nanoparticles, flame-retardant oligomers and polyester matrix, and reduce agglomeration, migration and washing loss; and how to stably introduce flame-retardant and antibacterial functions into the fiber interior and near-surface region through a masterbatch method suitable for polyester melt spinning, so that the resulting polyester textile fabric has flame retardancy, antibacterial properties, durability and industrial processing adaptability.

[0010] Based on this, it is necessary to develop a new method for preparing flame-retardant and antibacterial dual-functional polyester textile fabrics. By constructing a metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent, a stable adjacent distribution relationship is formed between the metal active sites and the phosphorus-nitrogen-silicon flame-retardant structure. During heating, the flame-retardant oligomers are dehydrated, condensed, and charred in advance. At the same time, the metal active components provide antibacterial properties. Furthermore, the functional components are stably embedded in the polyester fibers through masterbatch and melt spinning, thereby improving the problems of insufficient flame-retardant efficiency, poor antibacterial durability, and weak synergy of functional components in existing flame-retardant and antibacterial polyester fabrics. Summary of the Invention

[0011] In view of the above analysis, the present invention aims to provide a method for preparing a flame-retardant and antibacterial dual-functional polyester textile fabric to solve the problems in the background art.

[0012] The objective of this invention is mainly achieved through the following technical solutions: A method for preparing a flame-retardant and antibacterial dual-functional polyester textile fabric includes the following steps: S1. Preparation of metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent; S2. The polyester carrier resin, the metal nanoparticle catalytic activated phosphorus nitrogen silicon flame retardant and antibacterial agent, the interface compatibilizer and the processing aid are mixed, and then melt-blended, extruded, cooled and pelletized to obtain flame retardant and antibacterial functional masterbatch. S3. The flame-retardant and antibacterial functional masterbatch is mixed with polyester chips, and then dried, melt-spun, cooled, oiled, stretched and wound to obtain flame-retardant and antibacterial dual-functional polyester fiber. S4. The flame-retardant and antibacterial dual-function polyester fiber is woven, knitted or nonwoven and then heat-set to obtain the flame-retardant and antibacterial dual-function polyester textile fabric. The content of the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent is 1-15 wt% based on the total mass of the flame-retardant and antibacterial bifunctional polyester fiber.

[0013] In one or more embodiments, step S1, the preparation of the metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent includes the following steps: S11. Disperse the zinc source and copper source in an alcohol-water mixture, adjust the pH of the system to alkaline, and allow the zinc and copper precursors to precipitate or undergo in-situ conversion reactions. After separation, washing, drying and heat treatment, composite metal oxide nanoparticles including zinc oxide and cuprous oxide are obtained. S12. The composite metal oxide nanoparticles are dispersed in a buffer solution, and a dopamine compound is added to carry out a surface coating reaction to form a polydopamine interface layer on the surface. Then, a phosphorylation modifier is added to allow the phosphorylation modifier to coordinate, hydrogen bond, or condensate with the polydopamine interface layer and / or the metal active sites on the surface of the composite metal oxide nanoparticles to obtain modified composite metal oxide nanoparticles with a phosphorylation interface layer on the surface. S13. Phosphorus-containing reactive monomers, nitrogen-containing reactive monomers and siloxane-containing reactive monomers undergo condensation, substitution and / or addition reactions to obtain phosphorus-nitrogen-silicon flame-retardant oligomers including phosphorus-containing structural units, nitrogen-containing structural units, siloxane structural units and metal-coordinating active groups. S14. The modified composite metal oxide nanoparticles are mixed and reacted with the phosphorus-nitrogen-silicon flame-retardant oligomer, so that the modified composite metal oxide nanoparticles and the phosphorus-nitrogen-silicon flame-retardant oligomer undergo interfacial bonding with the phosphorus-containing groups, silicon-containing groups and / or nitrogen-containing groups in the phosphorus-nitrogen-silicon flame-retardant oligomer to form a composite structure in which the metal active sites and the phosphorus-nitrogen-silicon flame-retardant structure are distributed adjacently. After separation, drying and pulverization, the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant antibacterial agent is obtained. The modified composite metal oxide nanoparticles are used to catalyze the dehydration, condensation and char formation of the phosphorus-nitrogen-silicon flame-retardant oligomers during heating, and to provide antibacterial activity.

[0014] In one or more embodiments, in step S1, the zinc source is one or more of zinc nitrate, zinc acetate, zinc chloride, and zinc sulfate; the copper source is one or more of copper nitrate, copper acetate, copper chloride, and copper sulfate; the alcohol-water mixture includes water and one or more of ethanol, methanol, and isopropanol; the zinc source and copper source are added at a Zn to Cu molar ratio of 95:5 to 60:40; the pH is adjusted to 8 to 12; the heat treatment temperature is 120 to 350°C; the heat treatment time is 1 to 6 hours; and the average particle size of the resulting composite metal oxide nanoparticles is 10 to 150 nm.

[0015] In one or more embodiments, in step S1, the buffer solution is a Tris buffer solution, a phosphate buffer solution, or a carbonate buffer solution, and the pH of the buffer solution is 7.5–9.5; the dopamine compound is one or more of dopamine hydrochloride, dopamine, and catecholamine compounds; the surface coating reaction temperature is 20–50°C, and the reaction time is 2–24 h; the phosphorylation modifier is one or more of phytic acid, phosphoric acid, phosphonic acid compounds, and phosphate ester silane coupling agents, and the mass ratio of the phosphorylation modifier to the composite metal oxide nanoparticles is 0.05–0.8:1.

[0016] In one or more embodiments, in step S1, the phosphorus-containing reactive monomer includes one or more of DOPO, DOPO derivatives, phosphonate compounds, phosphate ester compounds, and phosphoryl chloride compounds; the nitrogen-containing reactive monomer includes one or more of cyanuric chloride, melamine, dicyandiamide, aminotriazine compounds, and hydroxytriazine compounds; the siloxane-containing reactive monomer includes one or more of aminosilane coupling agents, epoxysilane coupling agents, hydroxyl-terminated polysiloxanes, amino-terminated polysiloxanes, and alkoxysilanes; and the metal coordinating active group... The modified composite metal oxide nanoparticles contain one or more of the following groups: phosphonic acid group, phosphate group, hydroxyl group, amino group, carboxyl group, silanol group, alkoxysilyl group, and triazine nitrogen coordination site. The mass ratio of the modified composite metal oxide nanoparticles to the phosphorus-nitrogen-silicon flame-retardant oligomer is 3-30:70-97. The mixing reaction temperature is 40-120℃, the reaction time is 2-12h, and the mixing reaction is carried out in one or more solvents selected from water, ethanol, methanol, isopropanol, N,N-dimethylformamide, and dimethyl sulfoxide, and a uniform dispersion system is formed under ultrasonic dispersion, mechanical stirring, or high-speed shearing conditions.

[0017] In one or more embodiments, in step S2, the flame-retardant and antibacterial functional masterbatch comprises, by weight: 50-85 parts of polyester carrier resin, 10-45 parts of metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent, 1-10 parts of interface compatibilizer, and 0.1-5 parts of processing aid.

[0018] In one or more embodiments, in step S2, the interface compatibilizer includes one or more of epoxy-based compatibilizers, anhydride-grafted polyester compatibilizers, silane coupling agents, carboxyl-containing polyester oligomers, and epoxy-containing polyester oligomers; the processing aid includes one or more of antioxidants, lubricants, dispersants, and heat stabilizers.

[0019] In one or more embodiments, in step S2, the melt blending temperature is 230–285°C, the screw speed is 100–500 r / min, and the moisture content of the resulting flame-retardant and antibacterial masterbatch is not higher than 500 ppm.

[0020] In one or more embodiments, in step S3, the mass ratio of the flame-retardant and antibacterial functional masterbatch to polyester chips is 5-35:65-95; the drying temperature is 120-180℃, and the drying time is 4-12h; the melt spinning temperature is 260-295℃, the draw ratio is 2.0-4.5 times, and the winding speed is 1000-4500m / min.

[0021] In one or more embodiments, in step S4, the temperature of the heat setting treatment is 150-210°C and the treatment time is 20-180s; the resulting flame-retardant and antibacterial dual-functional polyester textile fabric has a limiting oxygen index of not less than 28% and an antibacterial rate of not less than 90% against Staphylococcus aureus and Escherichia coli.

[0022] Principle of this invention This invention targets polyester fiber and addresses the problems of polyester material itself, such as low limiting oxygen index, easy melting and dripping after heating, weak char layer formation ability during combustion, and insufficient washability of conventional antibacterial finishing. It constructs a metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent, and introduces it into the polyester melt spinning system after mastering, so that the flame retardant and antibacterial functions exist stably in the polyester fiber and its fabric in an embedded manner.

[0023] The metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent uses phosphorus-nitrogen-silicon flame-retardant oligomers as the main flame-retardant framework. In these phosphorus-nitrogen-silicon flame-retardant oligomers, the phosphorus-containing structural units can generate phosphoric acid, polyphosphoric acid, or similar acidic phosphorus-containing structures when heated, promoting dehydration, condensation, and carbonization reactions of polyester pyrolysis products and the flame-retardant oligomers themselves. The nitrogen-containing structural units can release non-flammable gases or form nitrogen-containing carbonized structures during heating, diluting combustible gases in the combustion zone and improving the expansion and insulation properties of the carbon layer. The siloxane structural units can form silicon-oxygen networks or silicon-oxygen carbonized structures at high temperatures, improving the thermal stability, continuity, and anti-collapse ability of the carbon layer. Thus, phosphorus, nitrogen, and silicon structural units form a synergistic relationship as an acid source, gas source, and framework reinforcement source in the same oligomer system.

[0024] This invention further introduces composite metal oxide nanoparticles containing zinc and copper elements into phosphorus-nitrogen-silicon flame-retardant oligomers. After treatment with a polydopamine interface layer and a phosphorylated interface layer, these composite metal oxide nanoparticles possess numerous interfacial interaction sites such as hydroxyl, amino, phenolic hydroxyl, phosphate, or phosphonic acid groups on their surface. These sites can coordinate, hydrogen-bond, condensate, or adsorb onto the phosphorus-nitrogen-silicon flame-retardant oligomers, allowing them to interact with phosphorus-containing, silicon-containing, and / or nitrogen-containing groups in the phosphorus-nitrogen-silicon flame-retardant oligomers. This ensures that the active metal sites are not freely dispersed but rather distributed adjacent to the phosphorus-nitrogen-silicon flame-retardant structure. This structure enables the metal nanoparticles to directly participate in catalytic activation during the thermal decomposition and char formation of the flame retardant, rather than merely existing as inert fillers.

[0025] In the initial stage of heating, the metal active sites on the surface of zinc-copper composite metal oxide nanoparticles can interact with the phosphorus-oxygen, silicon-oxygen, and nitrogen-containing structures in the phosphorus-nitrogen-silicon flame-retardant oligomers, weakening the stability of some heat-sensitive bonds and promoting the earlier release of acid sources, dehydration condensation, and cross-linking to form char in the phosphorus-containing structures. In other words, the introduction of metal nanoparticles allows the flame-retardant system to enter the char formation protection stage before the polyester matrix undergoes severe thermal decomposition, enabling the flame retardant to begin functioning at a relatively low temperature, thereby improving the flame retardant's ability to intervene in the initial stage of polyester combustion.

[0026] During the combustion development stage, the phosphorus-containing structure promotes the formation of a phosphorus-containing carbonized layer on the surface of polyester and flame-retardant oligomers, while the nitrogen-containing structure assists in the formation of an expanded carbon layer. The siloxane structure further enhances the inorganic and densification degree of the carbon layer. Simultaneously, zinc and copper metal oxide nanoparticles and the inorganic active structures formed with the phosphorylated interface layer serve as micro-regional support points for carbon layer growth and cross-linking, promoting a more continuous, uniform, and dense carbon layer structure. This carbon layer can block the transfer of oxygen and heat into the polyester interior, inhibit the release of combustible pyrolysis gases, and reduce the risk of secondary combustion caused by molten polyester dripping.

[0027] Furthermore, the zinc and copper composite metal oxide nanoparticles also endow the system with antibacterial properties. During fabric use, the zinc and copper active components can influence bacterial cell membrane integrity, protease activity, and metabolic processes through trace metal ion release, surface contact disruption, and the induction of reactive oxygen species, thereby inhibiting common bacteria such as Staphylococcus aureus and Escherichia coli. Because the metal nanoparticles are jointly immobilized by the polydopamine interface layer, the phosphorylated interface layer, and the phosphorus-nitrogen-silicon flame-retardant oligomers, and further dispersed within the polyester fibers in an embedded manner, their antibacterial components are less likely to be rapidly lost during washing and friction, thus improving antibacterial durability.

[0028] Therefore, the essence of this invention is not simply to combine flame retardants and antibacterial agents, but to construct a functional system that couples "phosphorus-nitrogen-silicon flame retardant oligomers - phosphorylated interface layer - zinc-copper composite metal oxide nanoparticles". This allows the metal nanoparticles to simultaneously serve as a source of antibacterial activity and a center for flame retardant catalytic activation, while the phosphorus-nitrogen-silicon flame retardant oligomers simultaneously serve as a char-forming flame retardant framework and a carrier for anchoring metal active sites, thereby achieving a synergistic unity of flame retardancy, antibacterial properties, catalytic char formation, and durable fixation.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects: This invention employs a metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent as its core functional component. In this flame-retardant and antibacterial agent, the composite metal oxide nanoparticles, after modification with a polydopamine interface layer and a phosphorylated interface layer, form a stable interfacial bonding structure with the phosphorus-nitrogen-silicon flame-retardant oligomers. This ensures that the zinc and copper metal active sites are distributed adjacent to the phosphorus-, nitrogen-, and silicon-containing flame-retardant structures. This structure enables the metal active sites to participate in the thermal activation process of the phosphorus-nitrogen-silicon flame-retardant oligomers in the early stages of polyester heating, promoting earlier acid source release, dehydration condensation, and char formation reactions. This allows the flame-retardant system to form an initial charred protective layer before the polyester matrix undergoes extensive cracking and molten dripping, thus improving the flame retardant's ability to inhibit combustion in the early stages.

[0030] The phosphorus-nitrogen-silicon flame-retardant oligomers of this invention simultaneously contain phosphorus, nitrogen, and siloxane structures. The phosphorus-containing structure promotes carbonization of the polyester surface and reduces the release of combustible pyrolysis products; the nitrogen-containing structure assists in forming an expansion-insulating structure and dilutes combustible gases in the combustion zone; and the siloxane structure improves the heat resistance, continuity, and structural strength of the char layer. Zinc and copper composite metal oxide nanoparticles further serve as catalytic active centers and inorganic support points during char layer formation, promoting the formation of a denser protective layer between the phosphorus-containing char layer and the silicon-containing inorganic structure. This reduces the likelihood of cracking, collapse, and peeling of the char layer at high temperatures, thereby improving the problems of weak char formation, loose char layer, and insufficient flame-retardant efficiency in traditional polyester flame-retardant systems.

[0031] This invention endows composite metal oxide nanoparticles with dual functions of flame retardant catalysis and antibacterial activity. During combustion, the zinc and copper active components promote the early activation of the phosphorus-nitrogen-silicon flame retardant system and the densification of the char layer. During fabric use, they inhibit bacterial growth through metal ion release, surface contact, and reactive oxygen species. Therefore, the metal nanoparticles are not simply added as antibacterial fillers, but rather form synergistic functional units with flame-retardant oligomers. This allows both flame retardant and antibacterial properties to originate from the same composite structure, avoiding the problems of independent functions, uneven dispersion, poor compatibility, and insufficient durability that arise when traditional flame retardants and antibacterial agents are simply mixed.

[0032] This invention employs a polydopamine interface layer and a phosphorylated interface layer to regulate the surface of composite metal oxide nanoparticles. The polydopamine interface layer enhances the surface adhesion and dispersion stability of the metal oxide nanoparticles, while the phosphorylated interface layer provides phosphorus-containing char-forming structures and metal binding sites, making it easier for the metal nanoparticles to form stable bonds with phosphorus-nitrogen-silicon flame-retardant oligomers. This interface structure not only reduces the agglomeration tendency of nanoparticles during melt blending and spinning but also reduces the migration and loss of metal nanoparticles during fabric washing, friction, and use, thus contributing to improved retention of the flame-retardant and antibacterial properties of polyester fabrics.

[0033] This invention first prepares a functional masterbatch of a metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent, then blends it with polyester chips and melt-spun it. This allows the functional components to be embedded within the polyester fibers and in the near-surface region, rather than relying on a finishing coating to adhere to the fabric surface. The polyester carrier resin in the functional masterbatch improves the compatibility between the flame-retardant and antibacterial agent and the polyester matrix, the interface compatibilizer improves the interfacial bonding between the functional components and polyester segments, and the processing aids improve melt processing stability and spinning continuity. This reduces problems such as powder agglomeration, filter clogging, yarn breakage, and functional component separation, making this flame-retardant and antibacterial system more suitable for the industrial continuous production of polyester fibers.

[0034] The flame-retardant and antibacterial dual-functional polyester textile fabric obtained by this invention achieves both flame-retardant and antibacterial properties while maintaining the basic mechanical and processability properties of polyester fibers. Its flame-retardant properties originate from the early charring, expansion insulation, and silicon oxidation reinforcement effects of the phosphorus-nitrogen-silicon flame-retardant structure; its antibacterial properties originate from the sustained antibacterial effect of zinc and copper composite metal oxide nanoparticles; and its durability originates from the multi-level interface fixing structure formed between the polydopamine interface layer, the phosphorylated interface layer, the phosphorus-nitrogen-silicon flame-retardant oligomer, and the polyester matrix. Therefore, this fabric can balance flame retardancy, antibacterial properties, washability, spinnability, and fabric stability, making it suitable for applications requiring both flame retardancy and antibacterial properties, such as home textiles, decorative fabrics, public health textiles, vehicle interiors, and protective clothing. In this invention, the above-mentioned technical solutions can also be combined to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from the description and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0035] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0036] Figure 1This is a process flow diagram of the preparation method of the present invention. Detailed Implementation

[0037] In the following embodiments, unless otherwise stated, all raw materials used are commercially available.

[0038] Zinc acetate dihydrate can be purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with the brand or product number Z110779.

[0039] Copper acetate monohydrate can be purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., under the brand name or product number C433064.

[0040] Dopamine hydrochloride can be purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., under the brand or product number D103111.

[0041] Phytic acid can be purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., under the brand or product number P108518.

[0042] The hydroxyl-containing DOPO derivative, DOPO-HQ, is available from Tokyo Chemical Industry Co., Ltd., under the brand name or product number O0629.

[0043] Cyanogen chloride is available from Sigma-Aldrich under the brand name or product number C95501.

[0044] 3-Aminopropyltriethoxysilane is available from Nanjing Shuguang Chemical Group Co., Ltd., under the brand name KH-550.

[0045] Hydroxyl-terminated polysiloxane can be selected from hydroxyl-terminated polydimethylsiloxane, which has a kinematic viscosity of 16-32 cSt at 25°C. It is purchased from Gelest, Inc. and its brand name is DMS-S12.

[0046] Both the polyester carrier resin and the polyester chips can be fiber-grade polyester chips from Sinopec Yizheng Chemical Fiber Co., Ltd.

[0047] The epoxy compatibilizer can be a multifunctional epoxy chain extender from BASF SE, brand name Joncryl® ADR 4468.

[0048] Antioxidant 1010 can be selected from BASF SE's Irganox® 1010.

[0049] For polyester wax dispersion lubricant, Clariant AG's Licowax™ PE 520powder can be used.

[0050] In the examples, the hydroxyl-containing DOPO derivative is DOPO-HQ, namely 10-(2,5-dihydroxyphenyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, CAS number 99208-50-1; The hydroxyl-terminated polysiloxane is specifically hydroxyl-terminated polydimethylsiloxane.

[0051] In Example 1, the total volume of the alcohol-water mixture was 300 mL, the mass concentration of the glucose aqueous solution was 5 wt%, and the added volume was 20 mL; in Example 2, the total volume of the alcohol-water mixture was 300 mL, the mass concentration of the glucose aqueous solution was 5 wt%, and the added volume was 15 mL; in Example 3, the total volume of the alcohol-water mixture was 300 mL, the mass concentration of the glucose aqueous solution was 5 wt%, and the added volume was 25 mL.

[0052] The specific manufacturers, brands, or product numbers mentioned above are only used to illustrate the availability of the raw materials in the embodiments and do not constitute a limitation on the scope of protection of this invention. Those skilled in the art can choose commercially available raw materials with the same or similar functions to replace them according to actual needs. Concentration % refers to mass percentage; all substances used are commercially available.

[0053] Example 1 This embodiment provides a method for preparing a flame-retardant and antibacterial dual-functional polyester textile fabric, which includes the following steps.

[0054] S1. Preparation of metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent S11, Preparation of composite metal oxide nanoparticles Weigh 21.95 g of zinc acetate dihydrate and 4.00 g of copper acetate monohydrate, add them to an alcohol-water mixture consisting of ethanol and deionized water in a volume ratio of 7:3, and stir to dissolve, obtaining a mixed solution of metal salts. The molar ratio of Zn to Cu is approximately 83:17.

[0055] At 60°C, a 1 mol / L sodium hydroxide solution was added dropwise to the metal salt mixture to adjust the pH of the system to 10.0–10.5, causing precipitation and in-situ transformation of the zinc and copper precursors. Subsequently, a glucose aqueous solution was added as a mild reducing agent, and the reaction continued for 2 hours, partially converting the copper precursor into cuprous oxide. After the reaction, the resulting precipitate was centrifuged and washed sequentially with deionized water and ethanol, then dried at 80°C for 12 hours, and finally heat-treated at 220°C for 3 hours under a nitrogen atmosphere to obtain composite metal oxide nanoparticles comprising zinc oxide and cuprous oxide.

[0056] Particle size analysis revealed that the average particle size of the obtained composite metal oxide nanoparticles was approximately 55 nm.

[0057] S12. Surface modification of composite metal oxide nanoparticles Weigh 5.0g of the above composite metal oxide nanoparticles and add them to 500mL of Tris buffer solution with pH 8.5. After ultrasonic dispersion for 30min, add 0.5g of dopamine hydrochloride and stir at 30℃ for 8h to allow dopamine to self-polymerize on the surface of the composite metal oxide nanoparticles to form a polydopamine interface layer.

[0058] After the reaction was complete, 1.0 g of phytic acid was added to the system, and the mixture was stirred at 40 °C for 4 h to allow the phytic acid to coordinate, hydrogen bond, and condensate with the polydopamine interface layer and the metal active sites on the surface of the composite metal oxide nanoparticles. After the reaction was complete, the nanoparticles were centrifuged, washed, and dried to obtain modified composite metal oxide nanoparticles with a phosphorylated interface layer on the surface.

[0059] The mass ratio of phytic acid to composite metal oxide nanoparticles is 0.2:1.

[0060] S13, Preparation of phosphorus-nitrogen-silicon flame-retardant oligomers Under nitrogen protection, 18.4 g of cyanuric chloride was added to anhydrous acetone and dispersed under ice bath conditions with stirring, and the system temperature was controlled at 0-5℃. Then, 32.0 g of hydroxyl-containing DOPO derivative and 10.1 g of triethylamine were added, and after reacting for 2 h, the temperature was raised to 40℃ and the reaction was continued for 4 h to allow the phosphorus-containing reactive monomer to undergo a substitution reaction with the triazine nitrogen-containing reactive monomer.

[0061] Then, 22.0 g of 3-aminopropyltriethoxysilane and 20.0 g of hydroxyl-terminated polysiloxane were added to the system, and the mixture was heated to 75 °C and reacted for 6 h to further introduce the siloxane-containing reactive monomers into the reaction system. After the reaction was completed, the by-product salts were removed by filtration, the solvent was removed under reduced pressure, and the mixture was washed with ethanol and dried under vacuum to obtain the phosphorus-nitrogen-silicon flame-retardant oligomer.

[0062] The resulting phosphorus-nitrogen-silicon flame-retardant oligomers include phosphorus-containing structural units, nitrogen-containing triazine structural units, siloxane structural units, and phosphoxy, hydroxyl, amino, alkoxysilyl, and triazine nitrogen coordination sites that can interact with metal active sites.

[0063] S14, Constructing a catalytically activated composite structure Weigh 10.0g of modified composite metal oxide nanoparticles and 90.0g of phosphorus-nitrogen-silicon flame-retardant oligomers, add them to a mixed solvent of ethanol and deionized water in a volume ratio of 8:2, ultrasonically disperse for 30min, and then mechanically stir at 80℃ for 6h to allow the modified composite metal oxide nanoparticles to undergo interfacial bonding with the phosphorus-containing, silicon-containing, and nitrogen-containing groups in the phosphorus-nitrogen-silicon flame-retardant oligomers, forming a composite structure in which the metal active sites are adjacent to the phosphorus-nitrogen-silicon flame-retardant structure.

[0064] After the reaction was completed, the phosphorus-nitrogen-silicon flame retardant and antibacterial agent was obtained by separation, washing, vacuum drying at 80℃ and pulverization.

[0065] In this flame retardant and antibacterial agent, the mass ratio of modified composite metal oxide nanoparticles to phosphorus-nitrogen-silicon flame retardant oligomers is 10:90.

[0066] S2. Preparation of flame-retardant and antibacterial functional masterbatch Weigh the following raw materials by weight: Raw material weight 73.0 parts of polyester carrier resin Metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent, 20.0 parts 5.0 parts of epoxy-based polyester compatibilizer Antioxidant 10100.5 parts 1.5 parts of polyester wax-dispersed lubricant The above raw materials were premixed and then added to a twin-screw extruder for melt blending. The temperatures of zones one through five were set to 235℃, 250℃, 260℃, 268℃, and 275℃, respectively, with the die head temperature at 275℃ and the screw speed at 250 r / min. The extrudate was then water-cooled, air-dried, and pelletized to obtain flame-retardant and antibacterial masterbatch.

[0067] The obtained flame-retardant and antibacterial masterbatch was vacuum dried at 120℃ for 6 hours and the moisture content was measured to be approximately 320 ppm.

[0068] S3. Preparation of flame-retardant and antibacterial dual-functional polyester fibers The flame-retardant and antibacterial functional masterbatch was mixed with conventional polyester chips at a mass ratio of 30:70. Since the content of the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent in the flame-retardant and antibacterial functional masterbatch is 20 wt%, the content of the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent is 6 wt% based on the total mass of the final flame-retardant and antibacterial bifunctional polyester fibers.

[0069] The mixed chips were dried at 160℃ for 8 hours to reduce the moisture content to below 50ppm. Melt spinning was then performed, with the screw temperatures set sequentially to 270℃, 278℃, 283℃, 286℃, and 288℃ for zones one through five, and the spinning box temperature set to 288℃. The melt was metered by a metering pump and extruded from the spinneret, then cooled by side-blowing air, oiled, drawn, and wound to obtain flame-retardant and antibacterial bifunctional polyester filament.

[0070] The draw ratio is 3.2, the winding speed is 3000m / min, and the resulting polyester filament is 75D / 36F.

[0071] S4. Preparation of flame-retardant and antibacterial dual-functional polyester textile fabric The aforementioned flame-retardant and antibacterial dual-functional polyester filaments were used as warp and weft yarns for weaving to obtain a plain polyester fabric. The polyester fabric was then heat-set at 180°C for 60 seconds and cooled to obtain a flame-retardant and antibacterial dual-functional polyester textile fabric.

[0072] Example 2 This embodiment provides a method for preparing a flame-retardant and antibacterial dual-functional polyester textile fabric. Compared with Example 1, the types of reagents used in this embodiment are the same, but the zinc-copper ratio of the composite metal oxide nanoparticles, the degree of surface modification, the ratio of each structural unit in the phosphorus-nitrogen-silicon flame-retardant oligomer, the composition of the functional masterbatch, and the melt spinning process parameters are adjusted.

[0073] S1. Preparation of metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent S11, Preparation of composite metal oxide nanoparticles Weigh 24.15 g of zinc acetate dihydrate and 2.22 g of copper acetate monohydrate, add them to an alcohol-water mixture consisting of ethanol and deionized water in a volume ratio of 6:4, and stir to dissolve, obtaining a mixed solution of metal salts. The molar ratio of Zn to Cu is approximately 90:10.

[0074] At 55°C, 1 mol / L sodium hydroxide solution was added dropwise to the metal salt mixture to adjust the pH of the system to 9.5–10.0, causing precipitation and in-situ transformation of the zinc and copper precursors. Subsequently, a glucose aqueous solution was added as a mild reducing agent, and the reaction continued for 3 hours, partially converting the copper precursor into cuprous oxide. After the reaction, the resulting precipitate was centrifuged and washed sequentially with deionized water and ethanol, then dried at 75°C for 10 hours, and finally heat-treated at 180°C for 4 hours under a nitrogen atmosphere to obtain composite metal oxide nanoparticles comprising zinc oxide and cuprous oxide.

[0075] Particle size analysis revealed that the average particle size of the obtained composite metal oxide nanoparticles was approximately 48 nm.

[0076] S12. Surface modification of composite metal oxide nanoparticles Weigh 5.0g of the above composite metal oxide nanoparticles and add them to 500mL of Tris buffer solution with pH 8.3. After ultrasonic dispersion for 40min, add 0.35g of dopamine hydrochloride and stir the mixture at 25℃ for 12h to allow dopamine to self-polymerize on the surface of the composite metal oxide nanoparticles to form a polydopamine interface layer.

[0077] After the reaction was complete, 0.75 g of phytic acid was added to the system, and the mixture was stirred at 35 °C for 6 h to allow the phytic acid to coordinate, hydrogen bond, and condensate with the polydopamine interface layer and the metal active sites on the surface of the composite metal oxide nanoparticles. After the reaction was complete, the nanoparticles were centrifuged, washed, and dried to obtain modified composite metal oxide nanoparticles with a phosphorylated interface layer on the surface.

[0078] The mass ratio of phytic acid to composite metal oxide nanoparticles is 0.15:1.

[0079] S13, Preparation of phosphorus-nitrogen-silicon flame-retardant oligomers Under nitrogen protection, 18.4 g of cyanuric chloride was added to anhydrous acetone and dispersed under ice bath conditions with stirring, and the system temperature was controlled at 0-5℃. Then, 36.0 g of hydroxyl-containing DOPO derivative and 11.0 g of triethylamine were added, and the reaction was carried out for 2.5 h. The temperature was then raised to 45℃ and the reaction was continued for 5 h to allow the phosphorus-containing reactive monomer to undergo a substitution reaction with the triazine nitrogen-containing reactive monomer.

[0080] Then, 18.0 g of 3-aminopropyltriethoxysilane and 24.0 g of hydroxyl-terminated polysiloxane were added to the system, and the mixture was heated to 80 °C and reacted for 5 h to further introduce the siloxane-containing reactive monomers into the reaction system. After the reaction was completed, the by-product salts were removed by filtration, the solvent was removed under reduced pressure, and the mixture was washed with ethanol and dried under vacuum to obtain the phosphorus-nitrogen-silicon flame-retardant oligomer.

[0081] The resulting phosphorus-nitrogen-silicon flame-retardant oligomers include phosphorus-containing structural units, nitrogen-containing triazine structural units, siloxane structural units, and phosphoxy, hydroxyl, amino, alkoxysilyl, and triazine nitrogen coordination sites that can interact with metal active sites.

[0082] S14, Constructing a catalytically activated composite structure Weigh 8.0g of modified composite metal oxide nanoparticles and 92.0g of phosphorus-nitrogen-silicon flame-retardant oligomers, add them to a mixed solvent of ethanol and deionized water in a volume ratio of 7:3, ultrasonically disperse for 45min, and then mechanically stir at 70℃ for 8h to allow the modified composite metal oxide nanoparticles to undergo interfacial bonding with the phosphorus-containing, silicon-containing, and nitrogen-containing groups in the phosphorus-nitrogen-silicon flame-retardant oligomers, forming a composite structure in which the metal active sites and the phosphorus-nitrogen-silicon flame-retardant structure are distributed adjacently.

[0083] After the reaction was completed, the phosphorus-nitrogen-silicon flame retardant and antibacterial agent was obtained by separation, washing, vacuum drying at 75°C and pulverization.

[0084] In this flame retardant and antibacterial agent, the mass ratio of modified composite metal oxide nanoparticles to phosphorus nitrogen silicon flame retardant oligomers is 8:92.

[0085] S2. Preparation of flame-retardant and antibacterial functional masterbatch Weigh the following raw materials by weight: Raw material weight 65.0 parts of polyester carrier resin Metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent, 28.0 parts. 5.0 parts of epoxy-based polyester compatibilizer Antioxidant 10100.5 parts 1.5 parts of polyester wax-dispersed lubricant The above raw materials were premixed and then added to a twin-screw extruder for melt blending. The temperatures of zones one through five were set to 240℃, 252℃, 262℃, 270℃, and 278℃, respectively, with the die head temperature at 278℃ and the screw speed at 300 r / min. The extrudate was then water-cooled, air-dried, and pelletized to obtain flame-retardant and antibacterial masterbatch.

[0086] The obtained flame-retardant and antibacterial masterbatch was vacuum dried at 120℃ for 8 hours and the moisture content was measured to be approximately 280 ppm.

[0087] S3. Preparation of flame-retardant and antibacterial dual-functional polyester fibers The flame-retardant and antibacterial functional masterbatch was mixed with conventional polyester chips at a mass ratio of 25:75. Since the content of the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent in the flame-retardant and antibacterial functional masterbatch is 28 wt%, the content of the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent is 7 wt% based on the total mass of the final flame-retardant and antibacterial bifunctional polyester fibers.

[0088] The mixed chips were dried at 165℃ for 7 hours to reduce the moisture content to below 50ppm. Melt spinning was then performed, with the screw temperatures set sequentially to 272℃, 280℃, 285℃, 288℃, and 290℃ for zones one through five, and the spinning box temperature set to 290℃. The melt was metered by a metering pump and extruded from the spinneret, then cooled by side-blowing air, oiled, drawn, and wound to obtain flame-retardant and antibacterial bifunctional polyester filament.

[0089] The draw ratio is 3.5, the winding speed is 3200m / min, and the resulting polyester filament is 75D / 36F.

[0090] S4. Preparation of flame-retardant and antibacterial dual-functional polyester textile fabric The aforementioned flame-retardant and antibacterial dual-functional polyester filaments were used as warp and weft yarns for weaving to obtain a plain polyester fabric. The polyester fabric was then heat-set at 185°C for 50 seconds and cooled to obtain a flame-retardant and antibacterial dual-functional polyester textile fabric.

[0091] Example 3 This embodiment provides a method for preparing a flame-retardant and antibacterial dual-functional polyester textile fabric. Compared with Embodiments 1 and 2, this embodiment increases the proportion of copper in the composite metal oxide nanoparticles and appropriately reduces the proportion of flame-retardant and antibacterial functional masterbatch added to the polyester fiber, so as to balance the catalytic char formation effect, antibacterial properties and spinning processing stability.

[0092] S1. Preparation of metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent S11, Preparation of composite metal oxide nanoparticles Weigh 16.46 g of zinc acetate dihydrate and 4.99 g of copper acetate monohydrate, add them to an alcohol-water mixture consisting of ethanol and deionized water in a volume ratio of 8:2, and stir to dissolve, obtaining a mixed solution of metal salts. The molar ratio of Zn to Cu is approximately 75:25.

[0093] At 65°C, 1 mol / L sodium hydroxide solution was added dropwise to the metal salt mixture to adjust the pH of the system to 10.8–11.2, causing precipitation and in-situ transformation of the zinc and copper precursors. Subsequently, a glucose aqueous solution was added as a mild reducing agent, and the reaction continued for 1.5 h, partially converting the copper precursor into cuprous oxide. After the reaction, the resulting precipitate was centrifuged and washed sequentially with deionized water and ethanol, then dried at 85°C for 10 h, and finally heat-treated at 250°C for 2 h under a nitrogen atmosphere to obtain composite metal oxide nanoparticles comprising zinc oxide and cuprous oxide.

[0094] Particle size analysis revealed that the average particle size of the obtained composite metal oxide nanoparticles was approximately 62 nm.

[0095] S12. Surface modification of composite metal oxide nanoparticles Weigh 5.0g of the above composite metal oxide nanoparticles and add them to 500mL of Tris buffer solution with pH 8.8. After ultrasonic dispersion for 35min, add 0.75g of dopamine hydrochloride and stir the mixture at 35℃ for 6h to allow dopamine to self-polymerize on the surface of the composite metal oxide nanoparticles to form a polydopamine interface layer.

[0096] After the reaction was complete, 1.5 g of phytic acid was added to the system, and the mixture was stirred at 45 °C for 3 h to allow the phytic acid to coordinate, hydrogen bond, and condensate with the polydopamine interface layer and the metal active sites on the surface of the composite metal oxide nanoparticles. After the reaction was complete, the nanoparticles were centrifuged, washed, and dried to obtain modified composite metal oxide nanoparticles with a phosphorylated interface layer on the surface.

[0097] The mass ratio of phytic acid to composite metal oxide nanoparticles is 0.3:1.

[0098] S13, Preparation of phosphorus-nitrogen-silicon flame-retardant oligomers Under nitrogen protection, 18.4 g of cyanuric chloride was added to anhydrous acetone and dispersed under ice bath conditions with stirring, and the system temperature was controlled at 0-5℃. Then, 30.0 g of hydroxyl-containing DOPO derivative and 10.5 g of triethylamine were added, and the reaction was carried out for 1.5 h. The temperature was then raised to 42℃ and the reaction was continued for 5 h to allow the phosphorus-containing reactive monomer to undergo a substitution reaction with the triazine nitrogen-containing reactive monomer.

[0099] Then, 24.0 g of 3-aminopropyltriethoxysilane and 18.0 g of hydroxyl-terminated polysiloxane were added to the system, and the mixture was heated to 78 °C and reacted for 7 h to further introduce the siloxane-containing reactive monomers into the reaction system. After the reaction was completed, the by-product salts were removed by filtration, the solvent was removed under reduced pressure, and the mixture was washed with ethanol and dried under vacuum to obtain the phosphorus-nitrogen-silicon flame-retardant oligomer.

[0100] The resulting phosphorus-nitrogen-silicon flame-retardant oligomers include phosphorus-containing structural units, nitrogen-containing triazine structural units, siloxane structural units, and phosphoxy, hydroxyl, amino, alkoxysilyl, and triazine nitrogen coordination sites that can interact with metal active sites.

[0101] S14, Constructing a catalytically activated composite structure Weigh 12.0g of modified composite metal oxide nanoparticles and 88.0g of phosphorus-nitrogen-silicon flame-retardant oligomers, add them to a mixed solvent of ethanol and deionized water in a volume ratio of 9:1, ultrasonically disperse for 25min, and then mechanically stir at 90℃ for 5h to allow the modified composite metal oxide nanoparticles to undergo interfacial bonding with the phosphorus-containing, silicon-containing, and nitrogen-containing groups in the phosphorus-nitrogen-silicon flame-retardant oligomers, forming a composite structure in which the metal active sites and the phosphorus-nitrogen-silicon flame-retardant structure are distributed adjacently.

[0102] After the reaction was completed, the phosphorus-nitrogen-silicon flame retardant and antibacterial agent was obtained by separation, washing, vacuum drying at 85℃ and pulverization.

[0103] In this flame retardant and antibacterial agent, the mass ratio of modified composite metal oxide nanoparticles to phosphorus-nitrogen-silicon flame retardant oligomers is 12:88.

[0104] S2. Preparation of flame-retardant and antibacterial functional masterbatch Weigh the following raw materials by weight: Raw material weight 70.0 parts of polyester carrier resin Metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent, 22.0 parts. 6.0 parts of epoxy-based polyester compatibilizer Antioxidant 10100.6 parts 1.4 parts of polyester wax-dispersed lubricant The above raw materials were premixed and then added to a twin-screw extruder for melt blending. The temperatures of zones one through five were set to 238℃, 250℃, 260℃, 266℃, and 272℃, respectively, with the die head temperature at 272℃ and the screw speed at 220 r / min. The extrudate was then water-cooled, air-dried, and pelletized to obtain flame-retardant and antibacterial masterbatch.

[0105] The obtained flame-retardant and antibacterial masterbatch was vacuum dried at 125℃ for 6 hours and the moisture content was measured to be approximately 350 ppm.

[0106] S3. Preparation of flame-retardant and antibacterial dual-functional polyester fibers The flame-retardant and antibacterial functional masterbatch was mixed with conventional polyester chips at a mass ratio of 35:65. Since the content of the metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent in the flame-retardant and antibacterial functional masterbatch is 22 wt%, the content of the metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent is 7.7 wt% based on the total mass of the final flame-retardant and antibacterial bifunctional polyester fibers.

[0107] The mixed chips were dried at 155℃ for 9 hours to reduce the moisture content to below 50ppm. Melt spinning was then performed, with the screw temperatures set sequentially to 268℃, 276℃, 282℃, 285℃, and 287℃ for zones one through five, and the spinning box temperature set to 287℃. The melt was metered by a metering pump and extruded from the spinneret, then cooled by side-blowing air, oiled, drawn, and wound to obtain flame-retardant and antibacterial bifunctional polyester filament.

[0108] The draw ratio is 3.0, the winding speed is 2800m / min, and the resulting polyester filament is 75D / 36F.

[0109] S4. Preparation of flame-retardant and antibacterial dual-functional polyester textile fabric The aforementioned flame-retardant and antibacterial dual-functional polyester filaments were used as warp and weft yarns for weaving to obtain a plain polyester fabric. The polyester fabric was then heat-set at 175°C for 80 seconds and cooled to obtain a flame-retardant and antibacterial dual-functional polyester textile fabric.

[0110] Comparative Example 1 Antibacterial particles without catalytic activation are used to replace composite metal oxide nanoparticles. This comparative example provides a method for preparing polyester textile fabric, which is basically the same as that in Example 1, except that the modified composite metal oxide nanoparticles described in Example 1 are replaced with an equal mass of silver-loaded silica antibacterial particles to investigate the effect of ordinary antibacterial particles on flame retardant catalytic activation.

[0111] Specifically, in preparing the flame-retardant and antibacterial agent, instead of using zinc oxide and cuprous oxide composite metal oxide nanoparticles, silver-loaded silica antibacterial particles with an average particle size of approximately 55 nm were used. 10.0 g of silver-loaded silica antibacterial particles and 90.0 g of the phosphorus-nitrogen-silicon flame-retardant oligomer prepared using the same method in Example 1 were weighed and added to a mixed solvent of ethanol and deionized water in a volume ratio of 8:2. After ultrasonic dispersion for 30 min, the mixture was mechanically stirred at 80 °C for 6 h. Following separation, washing, vacuum drying at 80 °C, and pulverization, the flame-retardant and antibacterial agent for Comparative Example 1 was obtained.

[0112] Subsequently, following the same method as in Example 1, the flame-retardant and antibacterial functional masterbatch of Comparative Example 1 was prepared by using a flame-retardant and antibacterial agent with polyester carrier resin, epoxy polyester compatibilizer, antioxidant 1010 and polyester wax dispersion lubricant; the obtained flame-retardant and antibacterial functional masterbatch was then mixed with polyester chips at a mass ratio of 30:70, and subjected to drying, melt spinning, cooling, oiling, stretching, winding, weaving and heat setting treatment to obtain the polyester textile fabric of Comparative Example 1.

[0113] Comparative Example 2 Using unmodified composite metal oxide nanoparticles This comparative example provides a method for preparing polyester textile fabric, which is basically the same as that in Example 1, except that the polydopamine coating and phosphorylation modification steps of the composite metal oxide nanoparticles in Example 1 are omitted, and flame retardant and antibacterial agent is prepared directly using unmodified composite metal oxide nanoparticles.

[0114] Specifically, composite metal oxide nanoparticles comprising zinc oxide and cuprous oxide were prepared according to the method in S11 of Example 1. The average particle size of the obtained composite metal oxide nanoparticles was approximately 55 nm. The difference was that this comparative example did not undergo dopamine hydrochloride coating treatment, nor was phytic acid added for phosphorylation modification.

[0115] Weigh 10.0g of the unmodified composite metal oxide nanoparticles and 90.0g of the phosphorus-nitrogen-silicon flame-retardant oligomer prepared by the same method in Example 1, add them to a mixed solvent of ethanol and deionized water in a volume ratio of 8:2, ultrasonically disperse for 30 min, and then mechanically stir and react at 80°C for 6 h. After separation, washing, vacuum drying at 80°C and pulverization, the flame-retardant and antibacterial agent for Comparative Example 2 is obtained.

[0116] Subsequently, following the same method as in Example 1, Comparative Example 2 was prepared into a flame-retardant and antibacterial functional masterbatch using a flame-retardant and antibacterial agent, and the polyester textile fabric of Comparative Example 2 was further prepared.

[0117] Comparative Example 3 Remove the phosphorylated interface layer, retaining only the polydopamine interface layer. This comparative example provides a method for preparing polyester textile fabric, which is basically the same as that in Example 1, except that only a polydopamine interface layer is formed on the surface of the composite metal oxide nanoparticles, and no phosphorylation modification treatment is performed.

[0118] Specifically, composite metal oxide nanoparticles comprising zinc oxide and cuprous oxide were prepared according to the method in S11 of Example 1. 5.0 g of the above composite metal oxide nanoparticles were weighed and added to 500 mL of Tris buffer solution with a pH of 8.5. After ultrasonic dispersion for 30 min, 0.5 g of dopamine hydrochloride was added, and the mixture was stirred at 30 °C for 8 h to allow dopamine to self-polymerize on the surface of the composite metal oxide nanoparticles, forming a polydopamine interface layer. After the reaction was completed, the nanoparticles were centrifuged, washed, and dried to obtain modified composite metal oxide nanoparticles with only the polydopamine interface layer.

[0119] This comparative example does not contain phytic acid and does not form a phosphorylated interface layer.

[0120] Weigh 10.0g of the modified composite metal oxide nanoparticles with only a polydopamine interface layer and 90.0g of the phosphorus-nitrogen-silicon flame-retardant oligomer prepared by the same method in Example 1, add them to a mixed solvent of ethanol and deionized water in a volume ratio of 8:2, ultrasonically disperse for 30 min, and then mechanically stir and react at 80°C for 6 h. After separation, washing, vacuum drying at 80°C and pulverization, the flame-retardant and antibacterial agent for Comparative Example 3 is obtained.

[0121] Subsequently, following the same method as in Example 1, Comparative Example 3 was prepared into a flame-retardant and antibacterial functional masterbatch using a flame-retardant and antibacterial agent, and the polyester textile fabric of Comparative Example 3 was further prepared.

[0122] Comparative Example 4 Direct physical mixing of modified composite metal oxide nanoparticles with phosphorus-nitrogen-silicon flame-retardant oligomers This comparative example provides a method for preparing polyester textile fabric, which is basically the same as that in Example 1, except that the modified composite metal oxide nanoparticles and phosphorus nitrogen silicon flame retardant oligomers are not mixed and reacted, but only prepared by room temperature physical mixing.

[0123] Specifically, modified composite metal oxide nanoparticles with a polydopamine interface layer and a phosphorylated interface layer on the surface were prepared according to the methods of S11 and S12 in Example 1; phosphorus-nitrogen-silicon flame-retardant oligomers were prepared according to the method of S13 in Example 1.

[0124] Weigh 10.0g of the modified composite metal oxide nanoparticles and 90.0g of the phosphorus-nitrogen-silicon flame-retardant oligomers, place them in a high-speed mixer, and mechanically mix them at room temperature for 10min. Do not disperse them in an ethanol / water mixed solvent, nor do you perform a mixing reaction at 80℃ for 6h, and directly obtain a physically mixed flame-retardant and antibacterial agent.

[0125] Subsequently, following the same method as in Example 1, the physically mixed flame retardant and antibacterial agent was combined with polyester carrier resin, epoxy polyester compatibilizer, antioxidant 1010, and polyester wax dispersion lubricant to form a flame retardant and antibacterial functional masterbatch; then, the obtained flame retardant and antibacterial functional masterbatch was mixed with polyester chips at a mass ratio of 30:70, and then subjected to drying, melt spinning, cooling, oiling, stretching, winding, weaving, and heat setting treatments to obtain the polyester textile fabric of Comparative Example 4.

[0126] The polyester textile fabrics obtained in Examples 1-3 and Comparative Examples 1-4 were subjected to performance testing.

[0127] 1. Limiting Oxygen Index Test The polyester textile fabrics obtained in Examples 1-3 and Comparative Examples 1-4 were cut into samples of specified sizes and conditioned for 24 hours at a temperature of 20±2℃ and a relative humidity of 65±4%. The limiting oxygen index of each sample was tested according to the oxygen index method specified in GB / T 5454. At least 5 parallel samples were tested for each group of samples, and the average value was taken as the limiting oxygen index of the group of samples.

[0128] The higher the limiting oxygen index, the higher the oxygen concentration required for the fabric to sustain combustion, and the better its flame retardant properties.

[0129] 2. Vertical combustion performance test The polyester textile fabrics obtained in Examples 1-3 and Comparative Examples 1-4 were cut into samples of specified sizes and conditioned for 24 hours at a temperature of 20±2℃ and a relative humidity of 65±4%. Vertical burning tests were conducted according to the method specified in GB / T 5455, and the afterflame time, smoldering time, damage length, and molten droplet formation of each sample were recorded.

[0130] Each group of samples should be tested with no fewer than 5 parallel samples. The test values ​​of each parallel sample should be recorded and the average value should be calculated. The smaller the afterflame time, smoldering time, and damage length, the weaker the burning persistence of the fabric. The reduction or absence of molten droplets indicates that the flame retardant system can inhibit the polyester from melting and dripping when heated.

[0131] 3. Antibacterial performance test The antibacterial properties of the polyester textile fabrics obtained in Examples 1-3 and Comparative Examples 1-4 were tested using the oscillation method. Staphylococcus aureus and Escherichia coli were selected as the test bacteria. The sterilized fabric samples were shaken together with a certain concentration of bacterial solution and incubated for a specified time. The number of viable bacteria in the bacterial solution was measured, and the antibacterial rate was calculated according to the following formula: Antibacterial rate / % = (Number of viable bacteria in blank control sample - Number of viable bacteria in sample) / Number of viable bacteria in blank control sample × 100%.

[0132] At least three parallel samples were tested for each group of samples, and the average value was taken as the antibacterial rate of that group of samples. The higher the antibacterial rate, the stronger the inhibitory effect of the fabric on the corresponding bacteria.

[0133] 4. Thermogravimetric analysis and catalytic char formation test Flame retardant and antibacterial agents, flame retardant and antibacterial functional masterbatches, and polyester fabric samples obtained in Examples 1-3 and Comparative Examples 1-4 were subjected to thermogravimetric analysis (TGA) tests. The test atmosphere could be nitrogen or air, with a heating rate of 10°C / min and a test temperature range from room temperature to 700°C or 800°C.

[0134] Record the initial thermal decomposition temperature, the maximum weight loss peak temperature in the first stage, the main decomposition peak temperature, and the char residue at 700℃ for each sample, and compare the changes in the position of the thermal decomposition peak for each sample based on the DTG curve.

[0135] The test results are shown in Table 1 below.

[0136] Table 1 As shown in Table 1, the limiting oxygen indices of the flame-retardant and antibacterial dual-functional polyester textile fabrics obtained in Examples 1-3 were 30.2%, 30.8%, and 31.5%, respectively, all significantly higher than those in Comparative Examples 1-4. This indicates that the metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent used in this invention can effectively improve the flame-retardant performance of polyester fabrics. The afterflame time, smoldering time, and damage length of Examples 1-3 were all lower than those of the comparative examples, and the dripping phenomenon was significantly reduced. This indicates that the flame-retardant and antibacterial agent can not only increase the oxygen concentration required for the fabric to maintain combustion, but also inhibit the continuous combustion and dripping of the polyester matrix during combustion.

[0137] Thermogravimetric analysis results show that the maximum weight loss peak temperatures in the first stage of Examples 1-3 were 335℃, 333℃, and 328℃, respectively, which were lower than those in Comparative Examples 1-4. Meanwhile, the char residue rates of Examples 1-3 at 700℃ were 18.6%, 19.1%, and 20.3%, respectively, which were higher than those in Comparative Examples 1-4. These results indicate that the present invention does not simply increase the thermal decomposition temperature of the material, but rather enables the flame-retardant system to enter the dehydration, condensation, and char formation stages earlier in a lower temperature range. In other words, the zinc and copper metal active sites in the modified composite metal oxide nanoparticles can promote the early activation of phosphorus-nitrogen-silicon flame-retardant oligomers, allowing them to form an initial charred protective structure before the severe thermal decomposition and melting dripping of the polyester matrix, thereby improving the integrity and thermal shielding ability of the subsequent char layer.

[0138] The main decomposition peak temperatures of Examples 1-3 were 426℃, 424℃, and 421℃, respectively. Although slightly earlier than the comparative examples, their char residue rates were significantly improved, indicating that the role of metal nanoparticles is not simply to accelerate the thermal decomposition of materials, but rather to promote the shift of the phosphorus-nitrogen-silicon flame retardant system from a combustible pyrolysis pathway to a char-forming protective pathway. The phosphorus-containing structure promotes acid source generation and dehydration carbonization during heating, while the nitrogen-containing structure assists in the formation of an expansion and heat-insulating structure. The siloxane structure enhances the inorganic and densification degree of the char layer. Furthermore, the zinc and copper composite metal oxide nanoparticles serve as catalytic active centers and inorganic support points, promoting a more continuous, dense, and stable char layer. Therefore, Examples 1-3 exhibit shorter afterflame times, lower damage lengths, and less dripping.

[0139] Compared with Comparative Example 1, the antibacterial rates of Examples 1-3 were at a similar or higher level, but their flame retardant and char-forming properties were significantly superior. Comparative Example 1 used silver-loaded silica antibacterial particles instead of zinc-copper composite metal oxide nanoparticles, achieving antibacterial rates of 97.8% against Staphylococcus aureus and 96.9% against Escherichia coli, indicating that ordinary antibacterial particles can provide a certain antibacterial effect. However, Comparative Example 1 had a limiting oxygen index of only 27.6%, a char residue rate of only 13.4% at 700°C, and significantly higher afterflame time and damage length than the examples. This indicates that while silver-loaded silica antibacterial particles have antibacterial effects, they lack the catalytic activation ability for phosphorus-nitrogen-silicon flame-retardant oligomers, making it difficult to promote early char formation and the formation of a dense char layer in the flame-retardant system. Therefore, it can be proven that the zinc-copper composite metal oxide nanoparticles in this invention are not ordinary antibacterial fillers, but rather simultaneously serve as a source of antibacterial activity and a flame-retardant catalytic activation center.

[0140] Compared with Comparative Example 2, Examples 1-3 showed superior performance in limiting oxygen index, char residue, damage length, and antibacterial properties. Although Comparative Example 2 also used zinc oxide and cuprous oxide composite metal oxide nanoparticles, these nanoparticles were not coated with polydopamine or modified with phosphorylation. Their limiting oxygen index was 28.3%, and their char residue at 700°C was 14.7%, both lower than those of Examples 1-3. These results indicate that while unmodified composite metal oxide nanoparticles possess certain metal catalytic and antibacterial effects, their dispersion stability in phosphorus-nitrogen-silicon flame-retardant oligomers and polyester matrices is poor, making them prone to aggregation. This results in the metal active sites not being sufficiently and uniformly distributed adjacent to the phosphorus-nitrogen-silicon flame-retardant structure, thus limiting the catalytic char formation efficiency and antibacterial effect. The polydopamine interface layer and the phosphorylation interface layer play important roles in improving nanoparticle dispersion, enhancing interfacial bonding, and improving functional durability.

[0141] Compared with Comparative Example 3, Examples 1-3 showed further improvements in limiting oxygen index and char residue at 700°C, while afterflame time and damage length were further reduced. Comparative Example 3 retained only the polydopamine interface layer without forming a phosphorylated interface layer, achieving a limiting oxygen index of 28.9% and a char residue at 700°C of 15.6%, which, while better than Comparative Example 2 without surface modification, was still lower than the examples. These results indicate that the polydopamine interface layer can improve the surface adhesion and dispersibility of the composite metal oxide nanoparticles, but relying solely on the polydopamine layer is insufficient to fully establish the synergistic relationship between the metal active sites and the phosphorus-containing flame-retardant structure. The phosphorylated interface layer provides a phosphorus-containing interface structure and metal binding sites, enabling the composite metal oxide nanoparticles to participate more effectively in the early dehydration, condensation, and char formation processes of the phosphorus-nitrogen-silicon flame-retardant oligomers, thus significantly improving flame-retardant efficiency and char layer density.

[0142] Compared to Comparative Example 4, Examples 1-3 exhibited higher limiting oxygen index, char residue, and antibacterial rate, and lower afterflame time and damage length. Although Comparative Example 4 contained both modified composite metal oxide nanoparticles and phosphorus-nitrogen-silicon flame-retardant oligomers, they were only combined through room-temperature physical mixing without undergoing a mixing reaction to form a stable composite structure. Its limiting oxygen index was 29.2%, and its char residue at 700°C was 16.2%, lower than Examples 1-3. This result indicates that while simple physical mixing can produce certain flame-retardant and antibacterial effects, the insufficient spatial adjacency and interfacial bonding stability between the metal active sites and the phosphorus-nitrogen-silicon flame-retardant structure limits the promoting effect of the metal active sites on the thermal activation process of the flame-retardant oligomers. The composite structure formed by the mixing reaction in this invention allows for a more complete adjacency distribution of the metal active sites with the phosphorus-, nitrogen-, and silicon-containing flame-retardant structures, thereby improving the catalytic activation char formation efficiency.

[0143] The results from Examples 1-3 also show that the flame retardant and antibacterial properties of the fabric show a certain upward trend as the proportion of copper in the composite metal oxide nanoparticles, the degree of phosphorylation modification, and the content of flame retardant and antibacterial agents in the fiber are adjusted. In Example 3, the molar ratio of Zn to Cu was approximately 75:25, the mass ratio of phytic acid to composite metal oxide nanoparticles was 0.3:1, and the final flame retardant and antibacterial agent content in the fiber was 7.7 wt%, with a limiting oxygen index of 31.5%, a char residue rate of 20.3% at 700℃, and antibacterial rates of 99.4% and 99.0% against Staphylococcus aureus and Escherichia coli, respectively. This indicates that appropriately increasing the content of copper active sites and the content of the phosphoric acid interface layer is beneficial to enhancing the catalytic char formation and antibacterial effects of the metal active sites, while also improving the promoting effect of the phosphorus-containing interface structure on char layer formation.

[0144] In summary, Examples 1-3 demonstrated superior results compared to Comparative Examples 1-4 in terms of flame retardancy, antibacterial properties, and catalytic char formation. This indicates that the beneficial effects of the present invention do not stem from a simple superposition of flame retardants and antibacterial agents, but rather from the synergistic effect between the composite metal oxide nanoparticles, the polydopamine interface layer, the phosphorylated interface layer, and the phosphorus-nitrogen-silicon flame-retardant oligomers. This synergistic structure enables the metal active sites to promote the early dehydration, condensation, and char formation of the phosphorus-nitrogen-silicon flame-retardant oligomers in the initial stage of heating. Simultaneously, the zinc and copper active components provide antibacterial properties, and the functional components are stably embedded in the polyester fiber system through masterbatch and melt spinning, thereby obtaining a bifunctional polyester textile fabric with flame retardancy, antibacterial properties, and char formation stability.

[0145] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a flame-retardant and antibacterial dual-functional polyester textile fabric, characterized in that, Includes the following steps: S1. Preparation of metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent; S2. The polyester carrier resin, the metal nanoparticle catalytic activated phosphorus nitrogen silicon flame retardant and antibacterial agent, the interface compatibilizer and the processing aid are mixed, and then melt-blended, extruded, cooled and pelletized to obtain flame retardant and antibacterial functional masterbatch. S3. The flame-retardant and antibacterial functional masterbatch is mixed with polyester chips, and then dried, melt-spun, cooled, oiled, stretched and wound to obtain flame-retardant and antibacterial dual-functional polyester fiber. S4. The flame-retardant and antibacterial dual-function polyester fiber is woven, knitted or nonwoven and then heat-set to obtain the flame-retardant and antibacterial dual-function polyester textile fabric. The content of the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent is 1-15 wt% based on the total mass of the flame-retardant and antibacterial bifunctional polyester fiber.

2. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S1, the preparation of the metal nanoparticle-catalyzed activated phosphorus-nitrogen-silicon flame retardant and antibacterial agent includes the following steps: S11. Disperse the zinc source and copper source in an alcohol-water mixture, adjust the pH of the system to alkaline, and allow the zinc and copper precursors to precipitate or undergo in-situ conversion reactions. After separation, washing, drying and heat treatment, composite metal oxide nanoparticles including zinc oxide and cuprous oxide are obtained. S12. The composite metal oxide nanoparticles are dispersed in a buffer solution, and a dopamine compound is added to carry out a surface coating reaction to form a polydopamine interface layer on the surface. Then, a phosphorylation modifier is added to allow the phosphorylation modifier to coordinate, hydrogen bond, or condensate with the polydopamine interface layer and / or the metal active sites on the surface of the composite metal oxide nanoparticles to obtain modified composite metal oxide nanoparticles with a phosphorylation interface layer on the surface. S13. Phosphorus-containing reactive monomers, nitrogen-containing reactive monomers and siloxane-containing reactive monomers undergo condensation, substitution and / or addition reactions to obtain phosphorus-nitrogen-silicon flame-retardant oligomers including phosphorus-containing structural units, nitrogen-containing structural units, siloxane structural units and metal-coordinating active groups. S14. The modified composite metal oxide nanoparticles are mixed and reacted with the phosphorus-nitrogen-silicon flame-retardant oligomer, so that the modified composite metal oxide nanoparticles and the phosphorus-nitrogen-silicon flame-retardant oligomer undergo interfacial bonding with the phosphorus-containing groups, silicon-containing groups and / or nitrogen-containing groups in the phosphorus-nitrogen-silicon flame-retardant oligomer to form a composite structure in which the metal active sites and the phosphorus-nitrogen-silicon flame-retardant structure are distributed adjacently. After separation, drying and pulverization, the metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant antibacterial agent is obtained. The modified composite metal oxide nanoparticles are used to catalyze the dehydration, condensation and char formation of the phosphorus-nitrogen-silicon flame-retardant oligomers during heating, and to provide antibacterial activity.

3. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S1, the zinc source is one or more of zinc nitrate, zinc acetate, zinc chloride, and zinc sulfate; the copper source is one or more of copper nitrate, copper acetate, copper chloride, and copper sulfate; the alcohol-water mixture includes water and one or more of ethanol, methanol, and isopropanol; the zinc source and copper source are added at a Zn to Cu molar ratio of 95:5 to 60:40; the pH is adjusted to 8 to 12; the heat treatment temperature is 120 to 350°C; the heat treatment time is 1 to 6 hours; and the average particle size of the resulting composite metal oxide nanoparticles is 10 to 150 nm.

4. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S1, the buffer solution is a Tris buffer solution, a phosphate buffer solution, or a carbonate buffer solution, and the pH of the buffer solution is 7.5–9.5; the dopamine compound is one or more of dopamine hydrochloride, dopamine, and catecholamine compounds; the surface coating reaction temperature is 20–50°C, and the reaction time is 2–24 h; the phosphorylation modifier is one or more of phytic acid, phosphoric acid, phosphonic acid compounds, and phosphate ester silane coupling agents, and the mass ratio of the phosphorylation modifier to the composite metal oxide nanoparticles is 0.05–0.8:

1.

5. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S1, the phosphorus-containing reactive monomer includes one or more of DOPO, DOPO derivatives, phosphonate compounds, phosphate ester compounds, and phosphoryl chloride compounds; the nitrogen-containing reactive monomer includes one or more of cyanuric chloride, melamine, dicyandiamide, aminotriazine compounds, and hydroxytriazine compounds; the siloxane-containing reactive monomer includes one or more of aminosilane coupling agents, epoxysilane coupling agents, hydroxyl-terminated polysiloxanes, amino-terminated polysiloxanes, and alkoxysilanes; and the metal coordinating active group includes phosphonic acid groups. The modified composite metal oxide nanoparticles contain one or more of the following groups: phosphate group, hydroxyl group, amino group, carboxyl group, silanol group, alkoxysilyl group, and triazine nitrogen coordination site; the mass ratio of the modified composite metal oxide nanoparticles to the phosphorus nitrogen silicon flame retardant oligomer is 3-30:70-97, the mixing reaction temperature is 40-120℃, the reaction time is 2-12h, the mixing reaction is carried out in one or more solvents selected from water, ethanol, methanol, isopropanol, N,N-dimethylformamide, and dimethyl sulfoxide, and a uniform dispersion system is formed under ultrasonic dispersion, mechanical stirring, or high-speed shearing conditions.

6. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S2, the flame-retardant and antibacterial functional masterbatch, by weight, comprises: 50-85 parts of polyester carrier resin, 10-45 parts of metal nanoparticle catalytically activated phosphorus-nitrogen-silicon flame-retardant and antibacterial agent, 1-10 parts of interface compatibilizer, and 0.1-5 parts of processing aid.

7. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S2, the interface compatibilizer includes one or more of epoxy-based compatibilizers, anhydride-grafted polyester compatibilizers, silane coupling agents, carboxyl-containing polyester oligomers, and epoxy-based polyester oligomers; the processing aid includes one or more of antioxidants, lubricants, dispersants, and heat stabilizers.

8. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S2, the melt blending temperature is 230–285°C, and the screw speed is 100–500 r / min; the moisture content of the resulting flame-retardant and antibacterial masterbatch is not higher than 500 ppm.

9. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S3, the mass ratio of the flame-retardant and antibacterial functional masterbatch to polyester chips is 5-35:65-95; the drying temperature is 120-180℃, and the drying time is 4-12h; the melt spinning temperature is 260-295℃, the draw ratio is 2.0-4.5 times, and the winding speed is 1000-4500m / min.

10. The method for preparing the flame-retardant and antibacterial dual-functional polyester textile fabric according to claim 1, characterized in that, In step S4, the temperature of the heat setting treatment is 150-210℃ and the treatment time is 20-180s; the limiting oxygen index of the obtained flame-retardant and antibacterial dual-function polyester textile fabric is not less than 28%, and the antibacterial rate against Staphylococcus aureus and Escherichia coli is not less than 90%.

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