Composite antibacterial fiber fabric and preparation method thereof

Abstract

The application relates to the technical field of fabrics, in particular to a composite antibacterial fiber fabric and a preparation method thereof. The preparation method comprises the following steps: pretreating and pre-adsorbing benzophenone on terylene cotton base cloth; preparing a first grafting solution containing polymerizable hydantoin monomers, N-vinyl-2-pyrrolidone and an inner salt monomer, and performing ultraviolet light-induced grafting; without water washing, the terylene cotton base cloth is directly immersed into a second grafting solution containing butyl acrylate to perform secondary grafting; and finally, the product is obtained through washing and chlorination regeneration. Through specific grafting monomers and a layered construction process, the fabric has high initial bacteriostatic rate, excellent washing resistance, multiple regeneration and performance recovery ability after resisting sweat pollution while maintaining good air permeability and mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of fabric technology, and in particular to a composite antibacterial fiber fabric and its preparation method. Background Technology

[0002] Currently, endowing textiles with durable and highly effective antibacterial properties is an important research direction in the field of functional textiles. Physical finishing methods, such as impregnation and coating, are simple to operate, but the antibacterial agents are usually bound to the fibers by physical adsorption or van der Waals forces, resulting in generally poor wash resistance. After repeated washing, the antibacterial performance drops sharply, and the residue of the additives may cause skin irritation or environmental problems.

[0003] To improve bonding strength, chemical grafting has been widely studied, which uses covalent bonds to fix antibacterial functional groups onto the fiber surface. Among these, N-haloamine compounds are considered a promising renewable antibacterial strategy because their antibacterial function can be restored through a mild chlorination / regeneration cycle (N-Cl / NH conversion). Existing technologies have attempted to introduce N-haloamine precursors such as hydantoin and amides onto the surface of cotton or polyester-cotton fabrics through surface finishing, free radical grafting, or covalent grafting, followed by hypochlorite treatment to form N-Cl antibacterial sites. These methods have, to some extent, solved the problems of initial antibacterial rate and durability after a certain number of washes.

[0004] However, this approach of achieving antibacterial properties through chlorination faces multiple challenges in practice. First, the stability of antibacterial sites depends not only on the initial grafting amount but also on their ability to maintain their activity under complex usage environments (such as repeated mechanical washing and sweat contamination) and their accessibility to rechlorination. While many technologies can achieve high initial antibacterial rates, their antibacterial performance significantly declines after more than 30 standard washes. Furthermore, after multiple (e.g., 5) chlorination regeneration cycles, the regeneration efficiency also decreases significantly, indicating that the antibacterial sites may suffer irreversible loss or inactivation during washing and regeneration.

[0005] Secondly, the unavoidable sweat contamination during daily use poses a severe challenge to the antibacterial regeneration ability of the N-haloamine system. Components such as organic salts and amino acids in sweat may occupy or block the rechlorination channels inside the fibers, or react with active chlorine sites, resulting in the fabric's antibacterial properties failing to effectively recover to the initial level even after standard chlorination treatment, meaning the "regeneration recovery rate after contamination" is low.

[0006] Furthermore, the pursuit of high antibacterial properties often comes at the expense of the textile's inherent wearability. Excessive chemical modification or overly thick functional layers can clog fabric pores, leading to decreased breathability; they may also damage the internal structure of the fibers, affecting the fabric's mechanical strength, such as warp tensile strength. Existing technologies often struggle to strike a balance between "high antibacterial properties" and "good wearability," either limiting the degree of functionalization to maintain fabric feel and strength, resulting in insufficient long-lasting antibacterial performance; or over-grafting to achieve high antibacterial properties, severely impacting the fabric's breathability and durability.

[0007] Therefore, developing a novel composite antibacterial fiber fabric and its preparation method, aiming to overcome the above-mentioned defects, and to achieve a comprehensive performance of high efficiency, long-lasting antibacterial function, multiple regeneration, and resistance to daily pollution (such as sweat) without significantly sacrificing the fabric's inherent practical performance, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0008] In view of this, the purpose of this invention is to propose a composite antibacterial fiber fabric and its preparation method, so as to solve the problem that existing N-haloamine antibacterial textiles are unable to maintain good fabric performance while achieving a synergistic balance in which antibacterial sites can be efficiently maintained and restored after multiple washings, chlorination regeneration and sweat contamination.

[0009] To achieve the above objectives, the present invention provides a composite antibacterial fiber fabric, comprising a polyester-cotton base fabric and a composite antibacterial grafted layer covalently grafted onto the surface of the polyester-cotton base fabric. Based on 100 parts by weight of the polyester-cotton base fabric, the composite antibacterial grafted layer is formed by stepwise ultraviolet light initiation grafting and chlorination of a system comprising the following components:

[0010] 5-7 parts by weight of benzophenone for pre-adsorption on the surface of the polyester-cotton base fabric;

[0011] 22-30 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 10-16 parts by weight of N-vinyl-2-pyrrolidone, and 2-4 parts by weight of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt are used to form the inner graft portion near the surface of the polyester-cotton base fabric.

[0012] And 6-10 parts by weight of butyl acrylate, 1-3 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and 0.5-1.5 parts by weight of N-vinyl-2-pyrrolidone for forming the outer graft portion in the unwashed state after the inner graft portion is formed;

[0013] In this embodiment, the hydantoin group in the 3-(4-vinylbenzyl)-5,5-dimethylhydantoin is converted into an N-Cl antibacterial site by chlorination.

[0014] Preferably, the inner grafted portion contains chlorinated hydantoin structural units, N-vinyl-2-pyrrolidone structural units, and internal salt-type hydration structural units; the outer grafted portion contains butyl acrylate flexible hydrophobic segments, chlorinated hydantoin structural units, and N-vinyl-2-pyrrolidone structural units.

[0015] Preferably, the polyester-cotton base fabric is a polyester-cotton blended twill fabric, wherein the mass ratio of polyester to cotton in the polyester-cotton blended twill fabric is 65:35.

[0016] Preferably, the 3-(4-vinylbenzyl)-5,5-dimethylhydantoin is prepared by reacting 5,5-dimethylhydantoin, anhydrous potassium carbonate, and 4-vinylbenzyl chloride in N,N-dimethylformamide; the mass ratio of 5,5-dimethylhydantoin, anhydrous potassium carbonate, 4-vinylbenzyl chloride, and N,N-dimethylformamide is 24-28:32-38:28-34:220-260.

[0017] Preferably, the first grafting solution used to form the inner graft portion comprises 22-30 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 2.5-3.5 parts by weight of benzophenone, 140-180 parts by weight of N,N-dimethylformamide, 330-390 parts by weight of anhydrous ethanol, 10-16 parts by weight of N-vinyl-2-pyrrolidone, 2-4 parts by weight of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt, and 140-180 parts by weight of deionized water.

[0018] Preferably, the second grafting solution used to form the outer grafted portion comprises 6-10 parts by weight of butyl acrylate, 1-3 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 0.5-1.5 parts by weight of N-vinyl-2-pyrrolidone, 1.5-2.5 parts by weight of benzophenone, 50-70 parts by weight of N,N-dimethylformamide, 160-200 parts by weight of anhydrous ethanol and 30-50 parts by weight of deionized water.

[0019] Preferably, the chlorination is carried out using a chlorination regeneration solution, wherein the chlorination regeneration solution contains a sodium hypochlorite solution with an effective chlorine mass fraction of 12%, and the mass ratio of deionized water to sodium bicarbonate is 3-5:995-997:0.8-1.2. Furthermore, the present invention also provides a method for preparing a composite antibacterial fiber fabric, comprising the following steps:

[0020] S1: Preparation of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin;

[0021] S2: The polyester-cotton base fabric is washed, treated with hot water and dried to obtain a pretreated base fabric;

[0022] S3: The pretreated base fabric is pre-adsorbed with benzophenone finishing solution to obtain a base fabric with benzophenone adsorbed on its surface;

[0023] S4: The base fabric with benzophenone adsorbed on the surface is immersed in the first grafting solution, rolled and sandwiched between transparent polyester films, and irradiated with 365nm ultraviolet light in a nitrogen atmosphere to obtain the inner grafted intermediate fabric.

[0024] S5: After step S4 is completed, without washing, the inner grafted intermediate fabric is directly transferred into the second grafting liquid, impregnated and rolled, and then irradiated with 365nm ultraviolet light and heat-treated in a nitrogen atmosphere to obtain the composite grafted fabric.

[0025] S6: Wash and dry the composite grafted fabric to obtain an unchlorinated composite grafted fabric.

[0026] S7: The unchlorinated composite grafted fabric is chlorinated using sodium hypochlorite / sodium bicarbonate chlorination regeneration solution, and after rinsing and drying, a composite antibacterial fiber fabric is obtained.

[0027] Preferably, in step S4, the intensity of the ultraviolet light irradiation is 25-35 mW / cm². 2 , front side irradiation for 5-7 minutes, back side irradiation for 5-7 minutes.

[0028] Preferably, in step S5, the intensity of the ultraviolet light irradiation is 25-35 mW / cm². 2 Irradiate the front side for 3-5 minutes, the back side for 3-5 minutes, and then treat in hot air at 55-65℃ for 25-35 minutes.

[0029] Preferably, in step S7, rinsing is performed by rinsing with deionized water until the free available chlorine in the washing solution is less than 1 mg / L.

[0030] The beneficial effects of this invention are:

[0031] (1) This invention significantly improves the density of grafting initiation sites and the binding stability of grafted layers of functional monomers on the surface of polyester-cotton fibers by pre-adsorbing benzophenone and combining it with ultraviolet light-induced grafting. As shown in Table 1, compared with Comparative Example 1 without pre-adsorbing benzophenone, the antibacterial rate of Example 1 after 30 washes increased significantly from 79.3% to 96.4%, effectively ensuring the washing durability of the antibacterial function.

[0032] (2) This invention uses polymerizable 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and introduces N-vinyl-2-pyrrolidone (NVP) and [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salts in a two-step process, and finally delays the introduction of butyl acrylate to construct a composite grafted structure with an "inner hydrophilic / outer hydrophobic flexible spacer". This structure has a significant synergistic effect. As shown in Table 1, the initial antibacterial rate of Example 3 is as high as 99.9%, and after 30 washes and 5 regenerations, the antibacterial rate still remains at an extremely high level of 98.2% and 98.6%, respectively. In particular, the regeneration recovery rate after sweat contamination in Example 4 reaches 96.4%, which proves the excellent anti-fouling ability of the inner salt structure and its ability to maintain the rechlorination channel.

[0033] (3) The composite grafting strategy of the present invention achieves excellent antibacterial performance while minimizing the impact on the fabric's intrinsic properties. The air permeability of all embodiments remained between 73.9 and 88.6 mm / s, and the warp breaking strength retention rate was between 89.8% and 94.5%. In contrast, Comparative Example 3, which simply increased the amount of hydantoin monomer, or Comparative Example 5, which incorrectly adjusted the monomer introduction order, showed a more significant decrease in air permeability and / or strength retention rate. This indicates that the layered grafting method of the present invention effectively achieves an excellent balance between antibacterial performance and wearability. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0035] The polyester-cotton blended twill fabric used is T / C65 / 35 Woven VATDyed Twill / Drill Fabric from Henan Tianyu Garment Import & Export Co., Ltd., with specifications of 16×12, density of 108×56, weight of 270GSM, and width of 58 / 59in. The transparent polyester film is laboratory-grade polyester film with a thickness of 75μm.

[0036] Example 1:

[0037] Step 1: Add 26g of 5,5-dimethylhydantoin, 35g of anhydrous potassium carbonate, and 240g of N,N-dimethylformamide to a reaction flask equipped with a mechanical stirrer, thermometer, and nitrogen gas delivery tube. Stir at 200r / min and purge with nitrogen for 15min, then continue stirring at 25℃ for 20min. Subsequently, add 31g of 4-vinylbenzyl chloride dropwise to the reaction flask over 30min. Heat to 55℃ and react in the dark for 8h. After the reaction is complete, cool to 25℃, filter to remove inorganic salts, pour the filtrate into 1600g of deionized water, and stir at 300r / min for 30min. Collect the precipitated solid, wash with deionized water until the conductivity of the washing solution is below 100μS / cm, and then vacuum dry at 45℃ for 8h to obtain 3-(4-vinylbenzyl)-5,5-dimethylhydantoin.

[0038] Step 2: Place 100g of polyester-cotton blended twill fabric into 600g of anhydrous ethanol, stir and wash at 100r / min for 30min at 40℃, take it out and rinse with 1000g of deionized water for 10min, then place it in 1000g of deionized water and treat at 60℃ for 30min, and then dry it with hot air at 80℃ for 40min to obtain the pretreated base fabric;

[0039] Step 3: Add 6g of benzophenone to 600g of anhydrous ethanol and stir at 300r / min for 20min at 25℃. After the benzophenone dissolves, add 200g of deionized water and continue stirring for 10min to obtain a photoinitiator finishing solution. Immerse 100g of the pretreated base fabric obtained in Step 2 into the finishing solution for 20min, then roll it to control the fabric weight to 185g, and then dry it in hot air at 45℃ to constant weight to obtain a base fabric with benzophenone adsorbed on the surface.

[0040] Step 4: Add 26g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and 3g of benzophenone to a mixture of 160g of N,N-dimethylformamide and 360g of anhydrous ethanol, and stir at 300r / min for 30min at 25℃; separately add 13g of N-vinyl-2-pyrrolidone and 3g of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt to 160g of deionized water, and stir at 300r / min for 20min at 25℃; then mix the two liquids and purge with nitrogen for 20min to obtain the first grafting solution; immerse the benzophenone-adsorbed base fabric obtained in Step 3 in the first grafting solution for 10min, remove it, and roll it to control the fabric weight to 225g. Lay the fabric flat and sandwich it between transparent polyester films, and irradiate it with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 30mW / cm. 2 Irradiate the front side for 6 minutes and the back side for 6 minutes to obtain the inner grafted intermediate fabric.

[0041] Step 5: After completing Step 4, without washing, directly transfer the resulting inner grafted intermediate fabric into a second grafting solution composed of 8g butyl acrylate, 2g 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 1g N-vinyl-2-pyrrolidone, 2g benzophenone, 60g N,N-dimethylformamide, 180g anhydrous ethanol, and 40g deionized water. Immerse at 25°C for 5 minutes. After removal, roll to control the fabric weight to 185g. Subsequently, irradiate with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 30mW / cm. 2 The front side was irradiated for 4 minutes, the back side for 4 minutes, and then treated in hot air at 60℃ for 30 minutes to obtain the composite grafted fabric.

[0042] Step 6: Add the composite grafted fabric obtained in Step 5 to a washing solution consisting of 500g anhydrous ethanol and 500g deionized water, wash at 50℃ and 100r / min for 30min, remove and wash with 1000g deionized water at 25℃ for 10min, repeat the washing 3 times, and then dry with hot air at 70℃ for 40min to obtain the unchlorinated composite grafted fabric.

[0043] Step 7: Add 4g of sodium hypochlorite solution with an effective chlorine mass fraction of 12% determined by iodometric titration to 996g of deionized water, then add 1g of sodium bicarbonate and stir for 10min to obtain a chlorinated regeneration solution; immerse the unchlorinated composite grafted fabric obtained in Step 6 completely in the chlorinated regeneration solution, treat it at 25℃ at 80r / min for 10min, remove it and rinse it three times with 1000g of deionized water for 5min each time until the free effective chlorine in the washing solution is less than 1mg / L, and then dry it with hot air at 45℃ for 30min to obtain a composite antibacterial fiber fabric.

[0044] Example 2:

[0045] Step 1: Add 24g of 5,5-dimethylhydantoin, 32g of anhydrous potassium carbonate, and 220g of N,N-dimethylformamide to a reaction flask equipped with a mechanical stirrer, thermometer, and nitrogen gas delivery tube. Stir at 200r / min and purge with nitrogen for 15min, then continue stirring at 25℃ for 20min. Subsequently, add 28g of 4-vinylbenzyl chloride dropwise to the reaction flask over 25min. Heat to 50℃ and react in the dark for 7h. After the reaction is complete, cool to 25℃, filter to remove inorganic salts, pour the filtrate into 1500g of deionized water, and stir at 300r / min for 30min. Collect the precipitated solid, wash with deionized water until the conductivity of the washing solution is below 100μS / cm, and then vacuum dry at 42℃ for 6h to obtain 3-(4-vinylbenzyl)-5,5-dimethylhydantoin.

[0046] Step 2: Place 100g of polyester-cotton blended twill fabric into 500g of anhydrous ethanol, stir and wash at 35℃ and 100r / min for 25min, take it out and rinse with 900g of deionized water for 8min, then place it in 900g of deionized water and treat at 55℃ for 25min, and then dry it with hot air at 75℃ for 35min to obtain the pretreated base fabric.

[0047] Step 3: Add 5g of benzophenone to 550g of anhydrous ethanol and stir at 300r / min for 20min at 25℃. After the benzophenone dissolves, add 180g of deionized water and continue stirring for 10min to obtain a photoinitiator finishing solution. Immerse 100g of the pretreated base fabric obtained in Step 2 into the finishing solution for 15min, then roll it to control the fabric weight to 175g, and then dry it in hot air at 43℃ to constant weight to obtain a base fabric with benzophenone adsorbed on the surface.

[0048] Step 4: Add 22g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and 2.5g of benzophenone to a mixture of 140g of N,N-dimethylformamide and 330g of anhydrous ethanol, and stir at 300r / min for 30min at 25℃; separately add 10g of N-vinyl-2-pyrrolidone and 2g of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt to 140g of deionized water, and stir at 300r / min for 20min at 25℃; then mix the two liquids and purge with nitrogen for 15min to obtain the first grafting solution; immerse the benzophenone-adsorbed base fabric obtained in Step 3 in the first grafting solution for 8min, remove it, and roll it to control the fabric weight to 215g. Lay the fabric flat and sandwich it between transparent polyester films, and irradiate it with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 25mW / cm². 2 Irradiate the front side for 5 minutes and the back side for 5 minutes to obtain the inner grafted intermediate fabric.

[0049] Step 5: After completing Step 4, without washing, directly transfer the resulting inner grafted intermediate fabric into a second grafting solution composed of 6g butyl acrylate, 1g 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 0.5g N-vinyl-2-pyrrolidone, 1.5g benzophenone, 50g N,N-dimethylformamide, 160g anhydrous ethanol, and 30g deionized water. Immerse at 25°C for 4 minutes. After removal, roll to control the fabric weight to 175g. Subsequently, irradiate with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 25mW / cm². 2 Irradiate the front side for 3 minutes, irradiate the back side for 3 minutes, and then treat in hot air at 55℃ for 25 minutes to obtain the composite grafted fabric.

[0050] Step 6: Add the composite grafted fabric obtained in Step 5 to a washing solution consisting of 450g of anhydrous ethanol and 450g of deionized water, wash at 45℃ and 100r / min for 25min, remove and wash with 900g of deionized water at 25℃ for 10min, repeat the washing twice, and then dry with hot air at 65℃ for 35min to obtain the unchlorinated composite grafted fabric.

[0051] Step 7: Add 3g of sodium hypochlorite solution with an effective chlorine mass fraction of 12% determined by iodometric titration to 997g of deionized water, then add 0.8g of sodium bicarbonate and stir for 10min to obtain a chlorinated regeneration solution; immerse the unchlorinated composite grafted fabric obtained in Step 6 completely in the chlorinated regeneration solution, treat it at 25℃ at 80r / min for 8min, remove it and rinse it twice with 900g of deionized water, 5min each time, until the free effective chlorine in the washing solution is less than 1mg / L, and then dry it with hot air at 45℃ for 30min to obtain a composite antibacterial fiber fabric.

[0052] Example 3:

[0053] Step 1: Add 28g of 5,5-dimethylhydantoin, 38g of anhydrous potassium carbonate, and 260g of N,N-dimethylformamide to a reaction flask equipped with a mechanical stirrer, thermometer, and nitrogen gas delivery tube. Stir at 200r / min and purge with nitrogen for 15min, then continue stirring at 25℃ for 20min. Subsequently, add 34g of 4-vinylbenzyl chloride dropwise to the reaction flask over 35min. Heat to 60℃ and react in the dark for 9h. After the reaction is complete, cool to 25℃, filter to remove inorganic salts, pour the filtrate into 1700g of deionized water, and stir at 300r / min for 30min. Collect the precipitated solid, wash with deionized water until the conductivity of the washing solution is below 100μS / cm, and then vacuum dry at 48℃ for 10h to obtain 3-(4-vinylbenzyl)-5,5-dimethylhydantoin.

[0054] Step 2: Place 100g of polyester-cotton blended twill fabric into 700g of anhydrous ethanol, stir and wash at 100r / min for 35min at 45℃, take it out and rinse with 1100g of deionized water for 12min, then place it in 1100g of deionized water and treat at 65℃ for 35min, and then dry it with hot air at 85℃ for 45min to obtain the pretreated base fabric;

[0055] Step 3: Add 7g of benzophenone to 650g of anhydrous ethanol and stir at 300r / min for 20min at 25℃. After the benzophenone dissolves, add 220g of deionized water and continue stirring for 10min to obtain a photoinitiator finishing solution. Immerse 100g of the pretreated base fabric obtained in Step 2 into the finishing solution for 25min, then roll it to control the fabric weight to 195g, and then dry it in hot air at 47℃ to constant weight to obtain a base fabric with benzophenone adsorbed on the surface.

[0056] Step 4: Add 30g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and 3.5g of benzophenone to a mixture of 180g of N,N-dimethylformamide and 390g of anhydrous ethanol, and stir at 300r / min for 30min at 25℃; separately add 16g of N-vinyl-2-pyrrolidone and 4g of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt to 180g of deionized water, and stir at 300r / min for 20min at 25℃; then mix the two liquids and purge with nitrogen for 25min to obtain the first grafting solution; immerse the benzophenone-adsorbed base fabric obtained in Step 3 in the first grafting solution for 12min, remove it, and roll it to control the fabric weight to 235g. Lay the fabric flat and sandwich it between transparent polyester films, and irradiate it with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 35mW / cm. 2 Irradiate the front side for 7 minutes and the back side for 7 minutes to obtain the inner grafted intermediate fabric.

[0057] Step 5: After completing Step 4, without washing, directly transfer the resulting inner grafted intermediate fabric into a second grafting solution composed of 10g butyl acrylate, 3g 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 1.5g N-vinyl-2-pyrrolidone, 2.5g benzophenone, 70g N,N-dimethylformamide, 200g anhydrous ethanol, and 50g deionized water. Immerse at 25°C for 6 minutes. After removal, roll to control the fabric weight to 195g. Subsequently, irradiate with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 35mW / cm. 2 Irradiate the front side for 5 minutes, irradiate the back side for 5 minutes, and then treat in hot air at 65℃ for 35 minutes to obtain the composite grafted fabric.

[0058] Step 6: Add the composite grafted fabric obtained in Step 5 to a washing solution consisting of 550g of anhydrous ethanol and 550g of deionized water, wash at 55℃ and 100r / min for 35min, remove and wash with 1100g of deionized water at 25℃ for 10min, repeat the washing 4 times, and then dry with hot air at 75℃ for 45min to obtain the unchlorinated composite grafted fabric.

[0059] Step 7: Add 5g of sodium hypochlorite solution with an effective chlorine mass fraction of 12% as determined by iodometric titration to 995g of deionized water, then add 1.2g of sodium bicarbonate and stir for 10min to obtain a chlorinated regeneration solution; immerse the unchlorinated composite grafted fabric obtained in Step 6 completely in the chlorinated regeneration solution, treat it at 25℃ at 80r / min for 12min, remove it and rinse it 4 times with 1100g of deionized water for 5min each time until the free effective chlorine in the washing solution is less than 1mg / L, and then dry it with hot air at 45℃ for 30min to obtain a composite antibacterial fiber fabric.

[0060] Example 4:

[0061] Step 1: Add 25g of 5,5-dimethylhydantoin, 34g of anhydrous potassium carbonate, and 230g of N,N-dimethylformamide to a reaction flask equipped with a mechanical stirrer, thermometer, and nitrogen gas delivery tube. Stir at 200r / min and purge with nitrogen for 15min, then continue stirring at 25℃ for 20min. Subsequently, add 30g of 4-vinylbenzyl chloride dropwise to the reaction flask over 30min. Heat to 52℃ and react in the dark for 7.5h. After the reaction is complete, cool to 25℃, filter to remove inorganic salts, pour the filtrate into 1550g of deionized water, and stir at 300r / min for 30min. Collect the precipitated solid, wash with deionized water until the conductivity of the washing solution is below 100μS / cm, and then dry under vacuum at 44℃ for 7h to obtain 3-(4-vinylbenzyl)-5,5-dimethylhydantoin.

[0062] Step 2: Place 100g of polyester-cotton blended twill fabric into 580g of anhydrous ethanol, stir and wash at 38℃ and 100r / min for 28min, take it out and rinse with 950g of deionized water for 9min, then place it in 950g of deionized water and treat at 58℃ for 28min, and then dry it with hot air at 78℃ for 38min to obtain the pretreated base fabric.

[0063] Step 3: Add 5.5g of benzophenone to 580g of anhydrous ethanol, stir at 300r / min for 20min at 25℃, and after the benzophenone dissolves, add 190g of deionized water and continue stirring for 10min to obtain a photoinitiator finishing solution; immerse 100g of the pretreated base fabric obtained in Step 2 in the finishing solution for 18min, then roll it to control the fabric weight to 182g, and then dry it in hot air at 44℃ to constant weight to obtain a base fabric with benzophenone adsorbed on the surface;

[0064] Step 4: Add 24g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and 3g of benzophenone to a mixture of 150g of N,N-dimethylformamide and 350g of anhydrous ethanol, and stir at 300r / min for 30min at 25℃; separately add 16g of N-vinyl-2-pyrrolidone and 4g of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt to 150g of deionized water, and stir at 300r / min for 20min at 25℃; then mix the two liquids and purge with nitrogen for 18min to obtain the first grafting solution; immerse the benzophenone-adsorbed base fabric obtained in Step 3 in the first grafting solution for 9min, remove it, and roll it to control the fabric weight to 220g. Lay the fabric flat and sandwich it between transparent polyester films, and irradiate it with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 30mW / cm. 2 Irradiate the front side for 5.5 minutes and the back side for 5.5 minutes to obtain the inner grafted intermediate fabric;

[0065] Step 5: After completing Step 4, without washing, directly transfer the resulting inner grafted intermediate fabric into a second grafting solution composed of 6g butyl acrylate, 1.5g 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 1.5g N-vinyl-2-pyrrolidone, 2g benzophenone, 60g N,N-dimethylformamide, 180g anhydrous ethanol, and 40g deionized water. Immerse at 25°C for 5 minutes. After removal, roll to control the fabric weight to 182g. Subsequently, irradiate with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 30mW / cm. 2 The front side was irradiated for 4 minutes, the back side for 4 minutes, and then treated in hot air at 60℃ for 30 minutes to obtain the composite grafted fabric.

[0066] Step 6: Add the composite grafted fabric obtained in Step 5 to a washing solution consisting of 500g anhydrous ethanol and 500g deionized water, wash at 50℃ and 100r / min for 30min, remove and wash with 1000g deionized water at 25℃ for 10min, repeat the washing 3 times, and then dry with hot air at 70℃ for 40min to obtain the unchlorinated composite grafted fabric.

[0067] Step 7: Add 4g of sodium hypochlorite solution with an effective chlorine mass fraction of 12% determined by iodometric titration to 996g of deionized water, then add 1g of sodium bicarbonate and stir for 10min to obtain a chlorinated regeneration solution; immerse the unchlorinated composite grafted fabric obtained in Step 6 completely in the chlorinated regeneration solution, treat it at 25℃ at 80r / min for 10min, remove it and rinse it three times with 1000g of deionized water for 5min each time until the free effective chlorine in the washing solution is less than 1mg / L, and then dry it with hot air at 45℃ for 30min to obtain a composite antibacterial fiber fabric.

[0068] Example 5:

[0069] Step 1: Add 27g of 5,5-dimethylhydantoin, 37g of anhydrous potassium carbonate, and 250g of N,N-dimethylformamide to a reaction flask equipped with a mechanical stirrer, thermometer, and nitrogen gas delivery tube. Stir at 200r / min and purge with nitrogen for 15min, then continue stirring at 25℃ for 20min. Subsequently, add 33g of 4-vinylbenzyl chloride dropwise to the reaction flask over 30min. Heat to 58℃ and react in the dark for 8.5h. After the reaction is complete, cool to 25℃, filter to remove inorganic salts, pour the filtrate into 1650g of deionized water, and stir at 300r / min for 30min. Collect the precipitated solid, wash with deionized water until the conductivity of the washing solution is below 100μS / cm, and then dry under vacuum at 46℃ for 9h to obtain 3-(4-vinylbenzyl)-5,5-dimethylhydantoin.

[0070] Step 2: Place 100g of polyester-cotton blended twill fabric into 650g of anhydrous ethanol, stir and wash at 100r / min for 32min at 42℃, take it out and rinse with 1050g of deionized water for 11min, then place it in 1050g of deionized water and treat at 62℃ for 32min, and then dry it with hot air at 82℃ for 42min to obtain the pretreated base fabric;

[0071] Step 3: Add 6.5g of benzophenone to 620g of anhydrous ethanol, stir at 300r / min for 20min at 25℃, and after the benzophenone dissolves, add 210g of deionized water and continue stirring for 10min to obtain a photoinitiator finishing solution; immerse 100g of the pretreated base fabric obtained in Step 2 in the finishing solution for 22min, then roll it to control the fabric weight to 190g, and then dry it in hot air at 46℃ to constant weight to obtain a base fabric with benzophenone adsorbed on the surface;

[0072] Step 4: Add 30g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and 3.5g of benzophenone to a mixture of 175g of N,N-dimethylformamide and 380g of anhydrous ethanol, and stir at 300r / min for 30min at 25℃; separately add 10g of N-vinyl-2-pyrrolidone and 2g of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt to 175g of deionized water, and stir at 300r / min for 20min at 25℃; then mix the two liquids and purge with nitrogen for 22min to obtain the first grafting solution; immerse the benzophenone-adsorbed base fabric obtained in Step 3 in the first grafting solution for 11min, remove it, and roll it to control the fabric weight to 230g. Lay the fabric flat and sandwich it between transparent polyester films, and irradiate it with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 35mW / cm.2 Irradiate the front side for 6.5 minutes and the back side for 6.5 minutes to obtain the inner grafted intermediate fabric;

[0073] Step 5: After completing Step 4, without washing, directly transfer the resulting inner grafted intermediate fabric into a second grafting solution composed of 10g butyl acrylate, 3g 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 0.5g N-vinyl-2-pyrrolidone, 2.5g benzophenone, 70g N,N-dimethylformamide, 200g anhydrous ethanol, and 50g deionized water. Immerse at 25°C for 6 minutes. After removal, roll to control the fabric weight to 192g. Subsequently, irradiate with 365nm ultraviolet light in a nitrogen atmosphere with an ultraviolet light intensity of 35mW / cm². 2 Irradiate the front side for 5 minutes, irradiate the back side for 5 minutes, and then treat in hot air at 65℃ for 35 minutes to obtain the composite grafted fabric.

[0074] Step 6: Add the composite grafted fabric obtained in Step 5 to a washing solution consisting of 520g anhydrous ethanol and 520g deionized water, wash at 52℃ and 100r / min for 32min, remove and wash with 1050g deionized water at 25℃ for 10min, repeat the washing 4 times, and then dry with hot air at 72℃ for 42min to obtain the unchlorinated composite grafted fabric.

[0075] Step 7: Add 4.5g of sodium hypochlorite solution with an effective chlorine mass fraction of 12% as determined by iodometric titration to 995.5g of deionized water, then add 1.1g of sodium bicarbonate and stir for 10min to obtain a chlorinated regeneration solution; immerse the unchlorinated composite grafted fabric obtained in Step 6 completely in the chlorinated regeneration solution, treat it at 25℃ at 80r / min for 11min, remove it and rinse it 4 times with 1050g of deionized water for 5min each time until the free effective chlorine in the washing solution is less than 1mg / L, and then dry it with hot air at 45℃ for 30min to obtain a composite antibacterial fiber fabric.

[0076] Comparative Example 1:

[0077] The difference between Comparative Example 1 and Example 1 is that 6g of benzophenone was not added in step 3, and the mixture was made up with 6g of anhydrous ethanol. The remaining composition, impregnation, rolling, and drying conditions of the photoinitiator finishing solution were the same as in Example 1. All other conditions were the same as in Example 1.

[0078] Comparative Example 2:

[0079] The difference between Comparative Example 2 and Example 1 is that the 26g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin in step 4 is replaced with 26g of 5,5-dimethylhydantoin, and the 2g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin in step 5 is replaced with 2g of 5,5-dimethylhydantoin. All other conditions are the same as in Example 1.

[0080] Comparative Example 3:

[0081] The difference between Comparative Example 3 and Example 1 is that 13g of N-vinyl-2-pyrrolidone was not added in step 4, and 13g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin was used to make up the total mass of the graftable monomers in the first grafting solution. The remaining conditions were the same as in Example 1.

[0082] Comparative Example 4:

[0083] The difference between Comparative Example 4 and Example 1 is that in step 4, 3g of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt is not added, and 3g of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin is used to make up the total mass of the graftable monomers in the first grafting solution. The remaining conditions are the same as in Example 1.

[0084] Comparative Example 5:

[0085] The difference between Comparative Example 5 and Example 1 is that 8g of butyl acrylate in step 5 is added to the first grafting solution in step 4 beforehand, and butyl acrylate is not added to the second grafting solution in step 5. The total mass of the second grafting solution is made up with 8g of anhydrous ethanol. All other conditions are the same as in Example 1.

[0086] Comparative Example 6:

[0087] The difference between Comparative Example 6 and Example 1 is as follows: After step 4, the obtained inner grafted intermediate fabric is added to a washing solution consisting of 500g of anhydrous ethanol and 500g of deionized water, and washed at 50°C and 100r / min for 30min. After removal, it is washed with 1000g of deionized water at 25°C for 10min, and the washing is repeated 3 times. Then it is dried with hot air at 70°C for 40min, and then proceeds to step 5. The remaining conditions are the same as in Example 1.

[0088] Comparative Example 7:

[0089] The difference between Comparative Example 7 and Example 1 is that in step 7, 4g of sodium hypochlorite solution with an effective chlorine mass fraction of 12% determined by iodometric titration is not added, and 4g of deionized water is used to make up the total mass of the chlorination regeneration solution. The amount of sodium bicarbonate added, the treatment temperature, the treatment time, the rinsing method, and the drying conditions are all the same as in Example 1. All other conditions are the same as in Example 1.

[0090] Performance testing:

[0091] Sample preparation: The composite antibacterial fiber fabrics obtained in Examples 1-5 and Comparative Examples 1-7 were conditioned for 24 hours under standard atmospheric conditions of 20°C and 65% relative humidity. For antibacterial performance, wash durability, and recycling cycle testing, 0.75g of each sample was weighed. For air permeability and tensile strength testing, samples were cut to the dimensions specified in the corresponding standards. All cut samples avoided the area within 100mm of the fabric edge, and samples from the same sample should not be taken from the same warp and weft intersection.

[0092] Initial antibacterial performance: The initial inhibition rates of Examples 1-5 and Comparative Examples 1-7 against Staphylococcus aureus were tested according to GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Shaking method". Staphylococcus aureus was used as the test strain, and the bacterial suspension concentration was adjusted to 1.0 × 10⁻⁶. 5 CFU / mL. 0.75 g of each sample was weighed and placed in a 250 mL Erlenmeyer flask. 70 mL of phosphate buffer and 5 mL of bacterial suspension were added, and the mixture was shaken at 24 °C and 150 rpm for 18 h. After shaking, serial dilutions were performed, plates were plated, and the mixture was incubated at 37 °C for 24 h. The viable bacterial concentration was then counted. Untreated polyester-cotton blend twill fabric was used as a blank control, and the inhibition rate was calculated using the standard formula.

[0093] Antibacterial performance after 30 washes: The washing program was conducted according to GB / T 8629-2017 "Home Washing and Drying Procedures for Textile Testing", using a Type A standard washing machine, 4N washing program, washing temperature of 40℃, standard detergent, and a total washing load of 2.0 kg. After each wash, the samples were hung to dry, and the process was repeated 30 times. After washing, the samples were treated once under the chlorination regeneration conditions in step 7 of Example 1, and then the inhibition rate against Staphylococcus aureus was tested according to the shaking method in GB / T 20944.3-2008.

[0094] Antibacterial performance after 5 chlorination regeneration cycles: Samples from Examples 1-5 and Comparative Examples 1-7 were rinsed with deionized water after the antibacterial test, dried with hot air at 45°C for 30 min, chlorinated again according to step 7 of Example 1, rinsed with deionized water until the free available chlorine in the washing solution was below 1 mg / L, and dried with hot air at 45°C for 30 min as one regeneration cycle. This process was repeated 5 times. After the 5th regeneration cycle, the inhibition rate against Staphylococcus aureus was tested according to the shaking method in GB / T 20944.3-2008 and compared with the initial inhibition rate.

[0095] Regeneration recovery rate after sweat contamination: Alkaline artificial sweat was prepared according to GB / T 3922-2013 "Textiles - Tests for Color Fastness to Perspiration". Samples from Examples 1-5 and Comparative Examples 1-7 were completely immersed in the artificial sweat at a liquor ratio of 1:50 and allowed to stand at 37°C for 2 hours. After removal, they were dried with hot air at 45°C for 30 minutes. Subsequently, chlorination regeneration was performed according to step 7 of Example 1, rinsing until the free available chlorine in the washing solution was below 1 mg / L and then drying. The inhibition rate against Staphylococcus aureus was then tested according to the shaking method in GB / T 20944.3-2008. The regeneration recovery rate after contamination was calculated as (inhibition rate after sweat contamination regeneration / initial inhibition rate) × 100%.

[0096] Air permeability: Air permeability was tested according to GB / T 5453-1997 "Textiles - Determination of Air Permeability of Fabrics". Examples 1-5, Comparative Examples 1-7, and untreated polyester-cotton blended twill fabrics were conditioned for 24 hours at 20°C and 65% relative humidity. The test area was 20 cm², and the pressure difference was 100 Pa. Ten locations were tested for each sample, avoiding creases and selvage. The air permeability was recorded and the average value was taken.

[0097] Tensile strength retention rate: Tensile strength was tested according to GB / T 3923.1-2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Tensile Strength and Elongation at Break (Strip Method)". Five strips were cut along the warp direction for each sample, with a strip width of 50 mm, an effective clamping distance of 200 mm, and a tensile speed of 100 mm / min. The maximum tensile strength was recorded. The tensile strength retention rate was calculated as: (Warp tensile strength of the treated sample / Warp tensile strength of the untreated polyester-cotton blend twill fabric) × 100%.

[0098] Table 1 Performance Test Results

[0099] Sample Initial inhibition rate (%) Antibacterial rate (%) after 30 washes and re-chlorination Antibacterial rate (%) after 5 chlorination regeneration cycles Regeneration and recovery rate after sweat contamination (%) Air permeability (mm / s) Meridional fracture strength retention rate (%) Example 1 99.8 96.4 97.1 94.6 80.4 92.7 Example 2 99.2 91.7 93.0 90.7 88.6 94.5 Example 3 99.9 98.2 98.6 95.8 73.9 89.8 Example 4 99.6 96.9 97.4 96.4 83.7 93.0 Example 5 99.7 94.1 94.9 87.9 75.1 90.6 Comparative Example 1 98.1 79.3 81.6 72.4 90.2 93.5 Comparative Example 2 73.6 34.8 39.2 42.8 96.8 95.2 Comparative Example 3 99.6 88.7 84.2 75.1 72.5 88.4 Comparative Example 4 99.5 92.8 92.1 67.8 76.1 90.1 Comparative Example 5 97.4 83.4 80.1 73.9 74.8 88.9 Comparative Example 6 96.5 86.7 84.8 77.2 84.9 91.3 Comparative Example 7 18.4 14.6 15.8 37.5 80.6 94.1

[0100] As shown in Table 1, although Comparative Example 7 underwent composite grafting treatment, it did not undergo sodium hypochlorite chlorination. As a result, the hydantoin sites in the fabric were difficult to be converted into N-Cl antibacterial sites with strong oxidative bactericidal effects. The initial inhibition rate against Staphylococcus aureus was only 18.4%, and the inhibition rates after 30 washes and 5 regenerations were still only 14.6% and 15.8%, respectively. This indicates that the chlorination step is a necessary condition for obtaining effective antibacterial properties.

[0101] Comparative Example 1 did not undergo surface pre-adsorption of benzophenone. Although the grafting solution still contained benzophenone and could form a certain grafting layer, the antibacterial rate dropped to 79.3% after 30 washes, indicating that pre-adsorption of benzophenone is beneficial to improving the bonding stability between the grafting layer and the surface of the polyester-cotton fiber.

[0102] In Comparative Example 2, after replacing the polymerizable 3-(4-vinylbenzyl)-5,5-dimethylhydantoin with the non-polymerizable 5,5-dimethylhydantoin, the antibacterial rate was only 34.8% after 30 washes, indicating that simple physical retention or weak interaction is insufficient to guarantee the fixation stability of hydantoin sites after repeated washing.

[0103] Comparative Example 3, which did not add N-vinyl-2-pyrrolidone but was supplemented with polymerizable hydantoin monomers, showed that its antibacterial rate after 30 washes, antibacterial rate after 5 regenerations, and regeneration recovery rate after sweat contamination decreased to 88.7%, 84.2%, and 75.1%, respectively. This indicates that simply increasing the number of hydantoin sites is not equivalent to improving the accessibility of repeated rechlorination.

[0104] Comparative Example 4, without the addition of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt, still maintained an initial antibacterial rate of 99.5% and an antibacterial rate of 92.1% after 5 regenerations, but the regeneration recovery rate after sweat contamination dropped to 67.8%, indicating that the inner salt-type hydration structure plays an important role in reducing sweat component contamination and maintaining rechlorination recovery ability.

[0105] In Comparative Example 5, after adding butyl acrylate to the first grafting solution in advance, the air permeability and strength retention rate decreased to 74.8 mm / s and 88.9%, respectively, and the antibacterial rate decreased to 80.1% after 5 regenerations. This indicates that the delayed introduction of butyl acrylate is beneficial to the formation of a more reasonable outer flexible spacer layer, avoiding its premature participation in the inner grafting and affecting the exposure and regeneration of N-Cl sites.

[0106] Comparative Example 6 showed that washing with water after the first grafting and then performing the second grafting resulted in a comprehensive decline in performance, indicating that not washing with water after the first grafting is beneficial for maintaining the continuity of subsequent layered construction.

[0107] In Examples 1-5, Example 3 achieved the following results due to sufficient amounts of polymerizable hydantoin monomer, N-vinyl-2-pyrrolidone, internal salt monomer, and butyl acrylate, as well as adequate light conditions: initial antibacterial rate, antibacterial rate after 30 washes, and antibacterial rate after 5 regenerations, reaching 99.9%, 98.2%, and 98.6%, respectively. Example 4 achieved the highest regeneration recovery rate of 96.4% after sweat contamination, due to its higher proportion of N-vinyl-2-pyrrolidone and internal salt monomer.

[0108] In summary, this invention, through the combination of benzophenone pre-adsorbed UV grafting, polymerizable hydantoin covalent fixation, N-vinyl-2-pyrrolidone-assisted rechlorination, internal salt-type hydration structure for stain resistance, and delayed introduction of butyl acrylate to construct a flexible outer layer, enables the fabric to maintain a breathability of 73.9-88.6 mm / s and a warp breaking strength retention rate of 89.8%-94.5%, while achieving high initial antibacterial rate, washability, and regenerable antibacterial properties. This demonstrates that the components are not simply superimposed, but rather form a synergistic effect in terms of antibacterial site fixation, rechlorination accessibility, and recovery after sweat staining.

[0109] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A composite antibacterial fiber fabric, comprising a polyester-cotton base fabric and a composite antibacterial graft layer covalently grafted onto the surface of the polyester-cotton base fabric, characterized in that, Based on 100 parts by weight of polyester-cotton base fabric, the composite antibacterial grafted layer is formed by stepwise ultraviolet light initiation grafting and chlorination of a system comprising the following components: 5-7 parts by weight of benzophenone for pre-adsorption on the surface of the polyester-cotton base fabric; 22-30 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 10-16 parts by weight of N-vinyl-2-pyrrolidone, and 2-4 parts by weight of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt are used to form the inner graft portion near the surface of the polyester-cotton base fabric. And 6-10 parts by weight of butyl acrylate, 1-3 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin and 0.5-1.5 parts by weight of N-vinyl-2-pyrrolidone for forming the outer graft portion in the unwashed state after the inner graft portion is formed; In this embodiment, the hydantoin group in the 3-(4-vinylbenzyl)-5,5-dimethylhydantoin is converted into an N-Cl antibacterial site by chlorination.

2. The composite antibacterial fiber fabric according to claim 1, characterized in that, The inner grafted portion contains chlorinated hydantoin structural units, N-vinyl-2-pyrrolidone structural units, and internal salt-type hydration structural units; the outer grafted portion contains butyl acrylate flexible hydrophobic segments, chlorinated hydantoin structural units, and N-vinyl-2-pyrrolidone structural units.

3. The composite antibacterial fiber fabric according to claim 1, characterized in that, The polyester-cotton base fabric is a polyester-cotton blended twill fabric, wherein the mass ratio of polyester to cotton in the polyester-cotton blended twill fabric is 65:

35.

4. The composite antibacterial fiber fabric according to claim 1, characterized in that, The 3-(4-vinylbenzyl)-5,5-dimethylhydantoin was prepared by reacting 5,5-dimethylhydantoin, anhydrous potassium carbonate, and 4-vinylbenzyl chloride in N,N-dimethylformamide; the mass ratio of 5,5-dimethylhydantoin, anhydrous potassium carbonate, 4-vinylbenzyl chloride, and N,N-dimethylformamide was 24-28:32-38:28-34:220-260.

5. The composite antibacterial fiber fabric according to claim 1, characterized in that, The first grafting solution used to form the inner grafted portion comprises 22-30 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 2.5-3.5 parts by weight of benzophenone, 140-180 parts by weight of N,N-dimethylformamide, 330-390 parts by weight of anhydrous ethanol, 10-16 parts by weight of N-vinyl-2-pyrrolidone, 2-4 parts by weight of [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide inner salt, and 140-180 parts by weight of deionized water.

6. The composite antibacterial fiber fabric according to claim 1, characterized in that, The second grafting solution used to form the outer grafted portion comprises 6-10 parts by weight of butyl acrylate, 1-3 parts by weight of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin, 0.5-1.5 parts by weight of N-vinyl-2-pyrrolidone, 1.5-2.5 parts by weight of benzophenone, 50-70 parts by weight of N,N-dimethylformamide, 160-200 parts by weight of anhydrous ethanol, and 30-50 parts by weight of deionized water.

7. The composite antibacterial fiber fabric according to claim 1, characterized in that, The chlorination is carried out using a chlorination regeneration solution, wherein the chlorination regeneration solution contains a sodium hypochlorite solution with an effective chlorine mass fraction of 12%, and the mass ratio of deionized water to sodium bicarbonate is 3-5:995-997:0.8-1.

2.

8. A method for preparing the composite antibacterial fiber fabric according to any one of claims 1-7, characterized in that, Includes the following steps: S1: Preparation of 3-(4-vinylbenzyl)-5,5-dimethylhydantoin; S2: The polyester-cotton base fabric is washed, treated with hot water and dried to obtain a pretreated base fabric; S3: The pretreated base fabric is pre-adsorbed with benzophenone finishing solution to obtain a base fabric with benzophenone adsorbed on its surface; S4: The base fabric with benzophenone adsorbed on the surface is immersed in the first grafting solution, rolled and sandwiched between transparent polyester films, and irradiated with 365nm ultraviolet light in a nitrogen atmosphere to obtain the inner grafted intermediate fabric. S5: After step S4 is completed, without washing, the inner grafted intermediate fabric is directly transferred into the second grafting liquid, impregnated and rolled, and then irradiated with 365nm ultraviolet light and heat-treated in a nitrogen atmosphere to obtain the composite grafted fabric. S6: Wash and dry the composite grafted fabric to obtain an unchlorinated composite grafted fabric. S7: The unchlorinated composite grafted fabric is chlorinated using sodium hypochlorite / sodium bicarbonate chlorination regeneration solution, and after rinsing and drying, a composite antibacterial fiber fabric is obtained.

9. The method for preparing the composite antibacterial fiber fabric according to claim 8, characterized in that, In step S4, the intensity of the ultraviolet light irradiation is 25-35 mW / cm². 2 Irradiate the front side for 5-7 minutes, and the back side for 5-7 minutes; in step S5, the ultraviolet light intensity of the ultraviolet light irradiation is 25-35 mW / cm². 2 Irradiate the front side for 3-5 minutes, the back side for 3-5 minutes, and then treat in hot air at 55-65℃ for 25-35 minutes.

10. The method for preparing the composite antibacterial fiber fabric according to claim 8, characterized in that, In step S7, rinsing is performed by rinsing with deionized water until the free available chlorine in the washing solution is less than 1 mg / L.