Multifunctional nylon textile sheath and preparation method and application thereof

Abstract

This invention discloses a multifunctional nylon textile sheath, its preparation method, and its applications, relating to the fields of surface modification and wire harness protection technology. The preparation method of the multifunctional nylon textile sheath includes: low-temperature drying of a nylon textile sheath impregnated with an organophosphorus liquid flame retardant; immersion and rolling in a first working solution containing dopamine hydrochloride, followed by washing and drying to form a polydopamine layer in situ on the surface; then immersion in a second working solution containing hyperbranched cyclodopamine and a crosslinking agent, followed by pre-drying and segmented baking, and finishing to fix a hyperbranched cyclodopamine layer on the surface of the polydopamine layer through a crosslinking reaction. This invention utilizes the physical barrier effect of the polydopamine bottom layer to prevent flame retardant loss, and combines the polyhydroxyl charring effect and hydrophobic cavities of the outer hyperbranched cyclodopamine layer to achieve dual flame retardancy in both the gas phase and condensed phase. Simultaneously, it can effectively adsorb and lock in volatile organic compounds (VOCs), significantly improving the environmental friendliness, safety, and wear resistance of the nylon sheath.

Description

Technical Field

[0001] This invention relates to the fields of surface modification and wire harness protection technology, and in particular to a multifunctional nylon textile sheath, its preparation method, and its application. Background Technology

[0002] Nylon textile sheaths are widely used in industrial and civilian fields such as cable protection, sports equipment, and rail transportation due to their excellent mechanical strength, abrasion resistance, and flexibility. With increasingly stringent safety and environmental standards across industries, the market is demanding higher functionalities from nylon textile sheaths, particularly in terms of flame retardancy and low volatile organic compound (VOC) emissions. Currently, the industry commonly uses surface finishing processes to impart flame retardant properties to nylon textile sheaths. One mainstream processing method is to apply liquid flame retardants containing phosphorus-nitrogen or intumescent components to the sheath surface via padding. While this method of externally coating liquid flame retardants is relatively simple and has minimal impact on the mechanical properties of the nylon substrate, it faces significant risks of functional failure and environmental degradation under actual long-term service conditions.

[0003] Existing liquid flame retardant coatings typically exhibit only a single physical adhesion state on the substrate surface, resulting in generally poor mechanical durability and water resistance. Due to the strong chemical inertness and lack of highly reactive groups on the nylon surface, conventional flame retardant coatings are prone to interfacial delamination when the sheath undergoes frequent bending, friction, or washing processes, leading to flame retardant loss and a sharp decline in flame retardant efficacy. A more significant drawback is that traditional finishing processes not only fail to effectively curb the slow release of residual volatiles from the nylon substrate, but the liquid flame retardant systems used often contain large amounts of small-molecule solvents and related additives. These small molecules, after coating curing or in subsequent heated environments, transform into new sources of volatile organic compound (VOC) release, significantly increasing the overall VOC content of the finished sheath and making it difficult to meet the stringent environmental limits for high-end applications. Currently, control measures for these pollutants are mostly limited to optimizing the upstream drawing process, lacking long-term source interception technologies for already formed surface-treated sheaths.

[0004] Given the objective limitations of the existing technology, the urgent technical problem to be solved in this field is how to develop a multi-interface modification and coating crosslinking construction technology for nylon textile sheaths with external liquid flame retardants. This technology aims to overcome the defects of poor coating adhesion and easy loss of flame retardant components caused by the chemical inertness of the nylon surface, and to construct a dense interfacial barrier on the sheath surface that can effectively seal and stabilize the underlying flame retardant system. Furthermore, it aims to further construct a spatial crosslinking network with durable molecular retention and adsorption functions on this solid interfacial layer, thereby actively capturing and physically locking the escape of dual volatile organic compounds from the nylon substrate and the underlying flame retardant during the use stage. Ultimately, while maintaining the original structural characteristics of the textile sheath, it aims to achieve the dual goals of high-durability flame retardancy and continuous low release of volatile organic compounds. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a multifunctional nylon textile sheath, its preparation method, and its application.

[0006] Firstly, a method for preparing a multifunctional nylon textile sheath, employing the following technical solution: A method for preparing a multifunctional nylon textile sheath includes the following steps: Step (1): Dry the nylon textile sheath impregnated with organophosphorus liquid flame retardant at low temperature; Step (2): The nylon textile sheath treated in step (1) is completely immersed in the first working solution, and after the liquid-pinching rate is controlled by rolling, it is dried and washed in sequence. Step (3): Immerse the nylon textile sheath treated in step (2) in the second working solution and roll it again with a rolling mill to control the total liquid rate. Step (4): The nylon textile sheath treated in step (3) is pre-dried and then baked in sections, followed by washing in warm water and drying to obtain the multifunctional nylon textile sheath. The first working solution contains dopamine hydrochloride and has a pH of 8.5 to 9.0; the second working solution contains hyperbranched cyclodextrin and a cross-linking agent and has a pH of 4.0 to 5.0.

[0007] Furthermore, the first working solution comprises the following components: 3 g / L to 5 g / L of dopamine hydrochloride, 1 g / L to 2 g / L of penetrant and 1 g / L to 6 g / L of feel modifier; The second working solution comprises the following components: 10 g / L to 30 g / L of hyperbranched cyclodextrin, 12 g / L to 18 g / L of crosslinking agent, 5 g / L to 10 g / L of catalyst and 5 g / L to 10 g / L of β-cyclodextrin.

[0008] Furthermore, the first working solution also contains an oxidant component, wherein the oxidant is selected from sodium percarbonate or hydrogen peroxide with a mass fraction of 25% to 35%; The penetrant is selected from nonionic fatty alcohol polyoxyethylene ether, wetting and penetrating agent JFC or AEO series fatty alcohol polyoxyethylene ether; The feel modifier is selected from amino silicone oil emulsion, polyethylene emulsion, or fatty acid amide; The pH of the first working solution is adjusted using a first pH adjuster, which is selected from borax buffer, triethanolamine or carbonate buffer.

[0009] Furthermore, in the second working solution, the hyperbranched cyclodextrin is a BETA-cyclodextrin-epoxychloropropane copolymer with a molecular weight of 3000-8000; The catalyst is sodium hypophosphite; The second working solution is adjusted to pH using a second pH adjuster, which is selected from an aqueous solution of citric acid with a mass fraction of 8%-12% or a diluted acetic acid solution.

[0010] Furthermore, in the second working solution, the crosslinking agent is selected from aqueous blocked isocyanate, ethylene glycol diglycidyl ether, or a combination of citric acid and glycerol; when the crosslinking agent is a combination of citric acid and glycerol, the mass concentration ratio of citric acid to glycerol in the second working solution is 1.5:1 to 2.5:1.

[0011] Further, in step (1), the temperature of the low-temperature drying is 75 ℃~95 ℃, and the drying time is 2 min~4 min; In step (2), the immersion time in the first working solution is 5 min to 15 min, the immersion temperature is 35℃ to 45℃, and the liquid surface is kept slightly aerated during the process; the controlled liquid rolling rate is 60% to 80% of the mass of the sheath after treatment in step (1); the drying temperature is 80℃ to 90℃, and the drying time is 3 min to 5 min; the water washing is done with warm water at 35℃ to 40℃.

[0012] Furthermore, in step (3), the immersion time in the second working solution is 30 s to 50 s; the total rolling yield is controlled to be 60% to 90% of the mass of the sheath after treatment in step (1).

[0013] Further, in step (4), the pre-baking is performed at a temperature of 100 ℃~110 ℃ for 1 min~3 min; the segmented baking includes the following process: first, transferring to a temperature of 130 ℃~140 ℃ for 1 min~4 min to allow the crosslinking agent to initially penetrate and react, and then rapidly raising the temperature to 155 ℃~165 ℃ for 1 min~4 min to complete the curing; the washing conditions in warm water are washing at a temperature of 40 ℃~60 ℃ for 1 min~3 min; the drying temperature is 75 ℃~90 ℃.

[0014] Secondly, a multifunctional nylon textile sheath adopts the following technical solution: A multifunctional nylon textile sheath is prepared by the preparation method described above; the nylon textile sheath includes a nylon substrate with an organophosphorus liquid flame retardant dried at low temperature, and the outer surface of the nylon substrate is sequentially and firmly grafted with a polydopamine layer formed by the self-polymerization of dopamine hydrochloride from the inside to the outside, and a hyperbranched cyclodextrin layer fixed on the surface of the polydopamine layer by a crosslinking reaction.

[0015] Thirdly, the application of a multifunctional nylon textile sheath adopts the following technical solution: An application of a multifunctional nylon textile sheath, as described above, in the manufacture of cable protection, sports equipment, or rail transit wiring harness protection devices.

[0016] The beneficial effects of this invention are: This invention provides a method for preparing a multifunctional nylon textile sheath. A polydopamine interfacial layer is formed by the self-polymerization of dopamine hydrochloride in a weakly alkaline working solution. This polydopamine layer forms a strong interfacial bond with the nylon substrate, not only densely encapsulating and stabilizing the previously impregnated organophosphorus liquid flame retardant within the substrate to prevent the flame retardant components from being detached or lost during friction or washing, but also improving the chemical inertness of the nylon surface and providing dense reactive sites for subsequent coatings. Subsequently, hyperbranched cyclodextrin is firmly grafted onto the surface of the polydopamine layer using a crosslinking agent in a slightly acidic working solution and a segmented baking process, thereby constructing a stable, multifunctional sheath. The inter-linked network, in which the unique hydrophobic cavity structure of hyperbranched cyclodextrin can actively capture and lock in free small molecule volatiles from the substrate and liquid flame retardant system through host-guest inclusion, thereby significantly reducing the release of volatile organic compounds during the use of the sheath. At the same time, the polyhydroxy skeleton rich in hyperbranched cyclodextrin itself acts as a highly efficient charring agent when heated, and produces a synergistic effect with the underlying organophosphorus flame retardant, constructing a dual flame retardant mechanism of gas phase and condensed phase. Ultimately, while maintaining the original structural characteristics of the nylon substrate, it endows the finished product with excellent and durable flame retardant properties and long-lasting air purification capabilities. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the following is a further detailed description of this application. The described embodiments should not be regarded as limitations on this invention. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0018] In the following description, references to "some embodiments" refer to a subset of all possible embodiments; however, it is understood that "some embodiments" may be the same or different subsets of all possible embodiments and may be combined with each other without conflict. Unless otherwise defined, all technical and scientific terms used in the embodiments of the invention have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiments of the invention pertain. The terminology used in the embodiments of the invention is for the purpose of describing the embodiments of the invention only and is not intended to limit the invention.

[0019] Those skilled in the art should understand that, in the following description of the embodiments of the present invention, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0020] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0021] Those skilled in the art will understand that the numerical ranges in the embodiments of the present invention should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any stated value and an intermediate value within the stated range, as well as any other stated value or an intermediate value within the stated range, is also included within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0022] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may be used in embodiments or test cases of the invention. All references to this specification are generally incorporated herein by reference to disclose and describe methods and / or materials associated with said references. In the event of any conflict with any incorporated reference, the contents of this application shall prevail.

[0023] It should be noted that all raw materials and / or reagents in the embodiments of the present invention were purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0024] Example Example 1 This embodiment 1 provides a method for preparing a multifunctional nylon textile sheath, including the following steps: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 85 ℃ for 2 min.

[0025] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 3.0 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 1.0 g of wetting and penetrating agent JFC (nonionic fatty alcohol polyoxyethylene ether) and 2.0 g of amino silicone oil emulsion and stir evenly. Then weigh 8.00 g of sodium percarbonate, dissolve it in a small amount of water and add it to the solution while stirring. Use a 10% borax aqueous solution as the first pH adjuster and add it dropwise while monitoring with a pH meter until the pH stabilizes at 8.5. Finally, transfer it to a 1000 mL volumetric flask and dilute to volume with deionized water, shake well, and the first working solution is obtained.

[0026] Padding treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 5 minutes, during which the liquid surface is kept slightly aerated; after wetting, it is rolled with a rolling mill to control the liquid rolling rate at 75% (compared to the quality of the nylon textile sheath obtained after pretreatment); then the sheath is transferred to an 80 ℃ oven to dry for 4 minutes, and finally rinsed with 40 ℃ warm water in a water tank.

[0027] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 30.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55℃, and stir vigorously until completely dissolved and clear. Add 10.0 g of citric acid, 5.0 g of glycerol, 5.0 g of sodium hypophosphite, and 5.0 g of β-cyclodextrin sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, adding a small amount of 10% citric acid aqueous solution as a second pH adjuster until the pH stabilizes at 4.5. Finally, transfer to a 1000 mL volumetric flask and dilute to volume with deionized water, shaking well to obtain the second working solution.

[0028] Padding treatment: The nylon textile sheath that has been treated in step (2) is transferred into the second working solution for immersion for 30 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 85% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0029] Step (4), finishing and curing: Immediately after applying the second working fluid, the nylon textile sheath is pre-dried in a 105 ℃ oven for 2 min. The pre-dried nylon textile sheath is then quickly transferred to a 130 ℃ oven for 2.5 min to allow the crosslinking agent to initially penetrate and react. The temperature is then rapidly increased to 160 ℃ for 2.5 min to complete the curing process. The baked nylon textile sheath is then washed in 50 ℃ warm water for 2 min and finally dried in a 90 ℃ oven to constant weight, thus producing a multifunctional nylon textile sheath.

[0030] Example 2 This embodiment 2 provides a method for preparing a multifunctional nylon textile sheath, including the following steps: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 75 ℃ for 4 min.

[0031] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 5.0 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 2.0 g of penetration enhancer AEO-7 (AEO series fatty alcohol polyoxyethylene ether) and 1.0 g of polyethylene emulsion and stir. Then weigh 8.00 g of 30% hydrogen peroxide and add it while stirring. Use triethanolamine as the first pH adjuster and add it dropwise slowly while monitoring with a pH meter until the pH stabilizes at 9.0. Finally, transfer it to a 1000 mL volumetric flask and dilute to volume with deionized water, shake well, and obtain the first working solution.

[0032] Padding treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 15 min at a temperature of 35 ℃, with the liquid surface being slightly aerated during the process; after wetting, it is rolled with a rolling mill to control the liquid-to-liquid ratio at 60% (compared to the quality of the nylon textile sheath obtained after pretreatment); then the sheath is placed in a 90 ℃ oven to dry for 3 min, and finally rinsed with warm water at 35 ℃ in a water tank.

[0033] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 10.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 12.0 g of aqueous blocked isocyanate, 10.0 g of sodium hypophosphite, and 10.0 g of β-cyclodextrin sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, adding a small amount of diluted acetic acid solution as a second pH adjuster until the pH stabilizes at 4.0. Finally, transfer to a 1000 mL volumetric flask and dilute to volume with deionized water, shaking well to obtain the second working solution.

[0034] Padding treatment: The nylon textile sheath that has been treated in step (2) is transferred into the second working solution for immersion for 50 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 60% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0035] Step (4), finishing and curing: Immediately after applying the second working fluid, the nylon textile sheath is pre-dried in a 100°C oven for 3 minutes. The pre-dried nylon textile sheath is then quickly transferred to a 140°C oven for 1 minute to allow the crosslinking agent to initially penetrate and react. The temperature is then rapidly increased to 155°C for 4 minutes to complete the curing process. The baked nylon textile sheath is then washed in 40°C warm water for 3 minutes and finally dried in a 75°C oven to constant weight, thus producing a multifunctional nylon textile sheath.

[0036] Example 3 This embodiment 3 provides a method for preparing a multifunctional nylon textile sheath, including the following steps: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 95 ℃ for 2 min.

[0037] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 4.0 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 1.5 g of wetting and penetrating agent JFC (nonionic fatty alcohol polyoxyethylene ether) and 3.0 g of fatty acid amide and stir. Then weigh 8.00 g of sodium percarbonate, dissolve it in a small amount of water and add it to the solution while stirring. Use carbonate buffer as the first pH adjuster and add it dropwise, while monitoring with a pH meter, until the pH stabilizes at 8.8. Finally, transfer it to a 1000 mL volumetric flask and make up to volume with deionized water, shake well, and obtain the first working solution.

[0038] Padding treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 10 min at a temperature of 45 ℃, with the liquid surface being slightly aerated during the soaking process; after wetting, it is pressed with a padding machine to control the liquid-pickup rate at 80% (compared to the quality of the nylon textile sheath obtained after pretreatment); then the sheath is transferred to an oven at 85 ℃ for 5 min to dry, and finally rinsed with warm water at 40 ℃ in a water tank.

[0039] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 20.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 18.0 g of ethylene glycol diglycidyl ether, 7.5 g of sodium hypophosphite, and 7.5 g of β-cyclodextrin sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, and add a small amount of 10% citric acid aqueous solution as a second pH adjuster until the pH stabilizes at 5.0. Finally, transfer to a 1000 mL volumetric flask and dilute to volume with deionized water, shaking well to obtain the second working solution.

[0040] Padding treatment: The nylon textile sheath that has been treated in step (2) is immersed in the second working solution for 40 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 90% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0041] Step (4), finishing and curing: Immediately after applying the second working fluid, the nylon textile sheath is pre-dried in a 110°C oven for 1 minute. The pre-dried nylon textile sheath is then quickly transferred to a 135°C oven for 4 minutes to allow the crosslinking agent to initially penetrate and react. The temperature is then rapidly increased to 165°C for 1 minute to complete the curing process. The baked nylon textile sheath is then washed in 60°C warm water for 1 minute and finally dried in an 85°C oven to constant weight, thus producing a multifunctional nylon textile sheath.

[0042] Example 4 This embodiment 4 provides a method for preparing a multifunctional nylon textile sheath, including the following steps: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 80 ℃ for 3 min.

[0043] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 3.5 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 1.0 g of penetration enhancer AEO-9 (AEO series fatty alcohol polyoxyethylene ether) and 6.0 g of amino silicone oil emulsion and stir. Then weigh 8.00 g of 35% hydrogen peroxide and add it while stirring. Use borax buffer as the first pH adjuster and add it dropwise slowly while monitoring with a pH meter until the pH stabilizes at 8.6. Finally, transfer it to a 1000 mL volumetric flask and make up to volume with deionized water. Shake well to obtain the first working solution.

[0044] Padding treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 5 minutes at a temperature of 40°C, with the liquid surface being kept slightly aerated during the soaking process; after wetting, it is pressed with a padding machine to control the liquid-pickup rate at 70% (compared to the quality of the nylon textile sheath obtained after pretreatment); then the sheath is transferred to an oven at 88°C for 4 minutes to dry, and finally rinsed with warm water at 38°C in a water tank.

[0045] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 25.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 17.5 g of crosslinking agent (composed of 12.5 g of citric acid and 5.0 g of glycerol, mass ratio 2.5:1), 6.0 g of sodium hypophosphite, and 8.0 g of β-cyclodextrin sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, and add a small amount of 12% citric acid aqueous solution as a second pH adjuster until the pH stabilizes at 4.2. Finally, transfer to a 1000 mL volumetric flask, dilute to volume with deionized water, and shake well to obtain the second working solution.

[0046] Padding treatment: The nylon textile sheath that has been treated in step (2) is immersed in the second working solution for 35 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 75% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0047] Step (4), finishing and curing: Immediately after applying the second working fluid, the nylon textile sheath is pre-dried in a 105°C oven for 2.5 minutes. The pre-dried nylon textile sheath is then quickly transferred to a 130°C oven for 3 minutes to allow the crosslinking agent to initially penetrate and react. The temperature is then rapidly increased to 160°C for 3 minutes to complete the curing process. The baked nylon textile sheath is then washed in 45°C warm water for 2 minutes and finally dried in an 80°C oven to constant weight, thus producing a multifunctional nylon textile sheath.

[0048] Example 5 This embodiment 5 provides a method for preparing a multifunctional nylon textile sheath, including the following steps: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 90 ℃ for 2.5 min.

[0049] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 4.5 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 1.8 g of wetting and penetrating agent JFC and 4.0 g of polyethylene emulsion and stir. Next, weigh 8.00 g of 25% hydrogen peroxide and add it while stirring. Use triethanolamine as the first pH adjuster and add it dropwise slowly while monitoring with a pH meter until the pH stabilizes at 8.7. Finally, transfer it to a 1000 mL volumetric flask and dilute to volume with deionized water, shake well, and obtain the first working solution.

[0050] Padding treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 12 min at a temperature of 38 ℃, with the liquid surface being slightly aerated during the process; after wetting, it is rolled with a rolling mill to control the liquid-to-liquid ratio at 65% (compared to the quality of the nylon textile sheath obtained after pretreatment); then the sheath is placed in an oven at 82 ℃ for 4.5 min to dry, and finally rinsed with warm water at 37 ℃ in a water tank.

[0051] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 15.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 12.0 g of crosslinking agent (composed of 7.2 g of citric acid and 4.8 g of glycerol, mass ratio 1.5:1), 8.0 g of sodium hypophosphite, and 6.0 g of β-cyclodextrin sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, and add a small amount of 8% citric acid aqueous solution as a second pH adjuster until the pH stabilizes at 4.8. Finally, transfer to a 1000 mL volumetric flask, dilute to volume with deionized water, and shake well to obtain the second working solution.

[0052] Padding treatment: The nylon textile sheath that has been treated in step (2) is immersed in the second working solution for 45 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 80% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0053] Step (4), finishing and curing: Immediately after applying the second working fluid, the nylon textile sheath is pre-dried in a 108 ℃ forced-air oven for 1.5 min. The pre-dried nylon textile sheath is then quickly transferred to a 138 ℃ oven for 2 min to allow the crosslinking agent to initially penetrate and react. The temperature is then rapidly increased to 158 ℃ for 2 min to complete the curing process. The baked nylon textile sheath is then washed in 55 ℃ warm water for 2.5 min and finally dried in an 88 ℃ oven to constant weight, thus producing a multifunctional nylon textile sheath.

[0054] Example 6 This embodiment 6 provides a method for preparing a multifunctional nylon textile sheath, including the following steps: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 85 ℃ for 3.5 min.

[0055] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 5.0 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 2.0 g of AEO-7 osmotic agent and 5.0 g of fatty acid amide and stir. Next, weigh 8.00 g of sodium percarbonate, dissolve it in a small amount of water, add it and stir. Use carbonate buffer as the first pH adjuster and add it dropwise, while monitoring with a pH meter, until the pH stabilizes at 9.0. Finally, transfer it to a 1000 mL volumetric flask and make up to volume with deionized water, shake well, and obtain the first working solution.

[0056] Padding treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 8 minutes at a temperature of 42°C, with the liquid surface being kept slightly aerated during the soaking process; after wetting, it is pressed with a padding machine to control the liquid-pickup rate at 78% (compared to the quality of the nylon textile sheath obtained after pretreatment); then the sheath is placed in an oven at 80°C for 5 minutes to dry, and finally rinsed with warm water at 40°C in a water tank.

[0057] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 30.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 15.0 g of crosslinking agent (composed of 10.0 g of citric acid and 5.0 g of glycerol, mass ratio 2:1), 10.0 g of sodium hypophosphite, and 10.0 g of β-cyclodextrin sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, and add a small amount of diluted acetic acid solution as a second pH adjuster until the pH stabilizes at 4.5. Finally, transfer to a 1000 mL volumetric flask and dilute to volume with deionized water, shake well, and obtain the second working solution.

[0058] Padding treatment: The nylon textile sheath that has been treated in step (2) is immersed in the second working solution for 30 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 70% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0059] Step (4), finishing and curing: Immediately after applying the second working fluid, the nylon textile sheath is pre-dried in a 110°C oven for 2 minutes. The pre-dried nylon textile sheath is then quickly transferred to a 130°C oven for 4 minutes to allow the crosslinking agent to initially penetrate and react. The temperature is then rapidly increased to 165°C for 2.5 minutes to complete the curing process. The baked nylon textile sheath is then washed in 50°C warm water for 1.5 minutes and finally dried in a 90°C oven to constant weight, thus producing a multifunctional nylon textile sheath.

[0060] Comparative Example Comparative Example 1 Comparative Example 1 provides a method for preparing a nylon textile sheath, which differs from Example 1 in that only the low-temperature drying in step (1) is performed, without subsequent coating treatment. The specific steps are as follows: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath, which is impregnated with an organophosphorus liquid flame retardant, is dried at a low temperature of 85 ℃ for 2 min to obtain the nylon textile sheath.

[0061] Comparative Example 2 Comparative Example 2 provides a method for preparing a multifunctional nylon textile sheath, which differs from Example 1 in that the first working fluid coating treatment in step (2) is omitted. The specific steps are as follows: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 85 ℃ for 2 min.

[0062] Step (2), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 30.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 10.0 g of citric acid, 5.0 g of glycerol, 5.0 g of sodium hypophosphite, and 5.0 g of β-cyclodextrin sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, adding a small amount of 10% citric acid aqueous solution as a pH adjuster until the pH stabilizes at 4.5. Finally, transfer to a 1000 mL volumetric flask and dilute to volume with deionized water, shaking well to obtain the second working solution.

[0063] Padding treatment: The nylon textile sheath that has been treated in step (1) is directly transferred into the second working solution for immersion for 30 seconds; it is then rolled with a rolling mill to control the total liquid rate at 85% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0064] Step (3), finishing and curing: Immediately after applying the second working fluid, the nylon textile sheath is placed in a 105°C forced-air oven for pre-drying for 2 minutes. The pre-dried nylon textile sheath is then quickly transferred to a 130°C oven for 2.5 minutes, followed by rapid heating to 160°C for another 2.5 minutes to complete curing. The cured nylon textile sheath is then washed in 50°C warm water for 2 minutes, and finally dried in a 90°C oven to constant weight, thus obtaining the nylon textile sheath.

[0065] Comparative Example 3 Comparative Example 3 provides a method for preparing a multifunctional nylon textile sheath, which differs from Example 1 in that the second working solution soaking and rolling step (3) is omitted. The specific steps are as follows: Step (1), pretreatment of nylon textile sheath: The nylon textile sheath impregnated with organophosphorus liquid flame retardant was dried at a low temperature of 85 ℃ for 2 min.

[0066] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 3.0 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 1.0 g of wetting and penetrating agent JFC and 2.0 g of amino silicone oil emulsion and stir. Next, weigh 8.00 g of sodium percarbonate, dissolve it in a small amount of water, add it and stir. Use a 10% borax aqueous solution as a pH adjuster and slowly add it dropwise, while monitoring with a pH meter, until the pH stabilizes at 8.5. Finally, transfer it to a 1000 mL volumetric flask and dilute to volume with deionized water, shake well, and the first working solution is obtained.

[0067] Padding treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 5 minutes, during which the liquid surface is kept slightly aerated; after wetting, it is rolled with a rolling mill to control the liquid rolling rate at 75% (compared to the quality of the nylon textile sheath obtained after pretreatment); then the sheath is transferred to an oven at 80 ℃ and dried for 4 minutes.

[0068] Step (3), finishing and curing: Immediately transfer the nylon textile sheath treated in step (2) into a forced-air oven at 105 ℃ for pre-drying for 2 min; quickly transfer the pre-dried nylon textile sheath to an oven at 130 ℃ for 2.5 min, then quickly raise the temperature to 160 ℃ for 2.5 min to complete curing; place the baked nylon textile sheath in warm water at 50 ℃ for 2 min, and finally dry it in an oven at 90 ℃ to constant weight to obtain the nylon textile sheath.

[0069] Comparative Example 4 Comparative Example 4 provides a method for preparing a multifunctional nylon textile sheath. The difference from Example 1 is that in step (3), hyperbranched cyclodextrin is not added; instead, an equal amount of ordinary β-cyclodextrin is used. The specific steps are as follows: Steps (1) and (2) are exactly the same as in Example 1.

[0070] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 35.0 g of β-cyclodextrin (i.e., replace the 30.0 g of hyperbranched cyclodextrin in Example 1 with 30.0 g of β-cyclodextrin, plus the original 5.0 g), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 10.0 g of citric acid, 5.0 g of glycerol, and 5.0 g of sodium hypophosphite in sequence, and stir until completely dissolved. Monitor with a pH meter, and add a small amount of 10% citric acid aqueous solution as a second pH adjuster to fine-tune until the pH stabilizes at 4.5. Finally, transfer to a 1000 mL volumetric flask and dilute to volume with deionized water, shake well, and obtain the second working solution.

[0071] Padding treatment: The nylon textile sheath that has been treated in step (2) is transferred into the second working solution for immersion for 30 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 85% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0072] Step (4) is exactly the same as in Example 1.

[0073] Comparative Example 5 Comparative Example 5 provides a method for preparing a multifunctional nylon textile sheath, which differs from Example 1 in that the second working solution in step (3) does not contain the citric acid and glycerol crosslinking agent system. The specific steps are as follows: Steps (1) and (2) are exactly the same as in Example 1.

[0074] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 30.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 5.0 g of sodium hypophosphite and 5.0 g of β-cyclodextrin (without citric acid and glycerol) sequentially, stirring until completely dissolved. Monitor the pH with a pH meter, adding a small amount of 10% dilute hydrochloric acid to finely adjust until the pH stabilizes at 4.5. Finally, transfer to a 1000 mL volumetric flask and dilute to volume with deionized water, shaking well to obtain the second working solution.

[0075] Padding treatment: The nylon textile sheath that has been treated in step (2) is transferred into the second working solution for immersion for 30 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 85% (compared to the quality of the nylon textile sheath obtained after pretreatment).

[0076] Step (4) is exactly the same as in Example 1.

[0077] Comparative Example 6 Comparative Example 6 provides a method for preparing a multifunctional nylon textile sheath. The difference from Example 1 is that the pH value of the first working solution in step (2) is set to 7.0. The specific steps are as follows: Step (1) is exactly the same as in Example 1.

[0078] Step (2), preparation of the first working solution and coating treatment: Preparation of the first working solution: Taking the preparation of 1 L of the first working solution as an example, weigh 3.0 g of dopamine hydrochloride, dissolve it in about 750 mL of deionized water and stir. Then add 1.0 g of wetting and penetrating agent JFC and 2.0 g of amino silicone oil emulsion and stir. Next, weigh 8.00 g of sodium percarbonate, dissolve it in a small amount of water, add it to the solution and stir. Monitor the pH with a pH meter and adjust it to a stable pH of 7.0. Finally, transfer the solution to a 1000 mL volumetric flask and dilute to volume with deionized water. Shake well to obtain the first working solution.

[0079] Pulping treatment: The nylon textile sheath treated in step (1) is completely immersed in the first working solution for 5 minutes, during which the liquid surface is kept slightly aerated; after wetting, it is pressed with a rolling mill to control the liquid rolling rate at 75%; then the sheath is transferred to an 80°C oven to dry for 4 minutes, and finally rinsed with 40°C warm water in a water tank.

[0080] Steps (3) and (4) are exactly the same as in Example 1.

[0081] Comparative Example 7 Comparative Example 7 provides a method for preparing a multifunctional nylon textile sheath. The difference from Example 1 is that the pH value of the second working solution in step (3) is set to 7.0. The specific steps are as follows: Steps (1) and (2) are exactly the same as in Example 1.

[0082] Step (3), preparation and soaking / rolling of the second working solution: Preparation of the second working solution: Taking the preparation of 1 L of the second working solution as an example, weigh 30.0 g of hyperbranched cyclodextrin (BETA-cyclodextrin-epoxychloropropane copolymer, molecular weight 3000-8000), dissolve it in warm water at about 55 ℃, and stir vigorously until completely dissolved and clear. Add 10.0 g of citric acid, 5.0 g of glycerol, 5.0 g of sodium hypophosphite, and 5.0 g of β-cyclodextrin sequentially, stirring until completely dissolved. Adjust the pH with 10% sodium hydroxide solution until it stabilizes at 7.0. Finally, transfer the solution to a 1000 mL volumetric flask and dilute to volume with deionized water, shaking well to obtain the second working solution.

[0083] Padding treatment: The nylon textile sheath that has been treated in step (2) is transferred into the second working solution for immersion for 30 seconds; it is then rolled again with a rolling mill to control the total liquid rate at 85%.

[0084] Step (4) is exactly the same as in Example 1.

[0085] Comparative Example 8 Comparative Example 8 provides a method for preparing a multifunctional nylon textile sheath. The difference from Example 1 is that the curing process in step (4) skips pre-baking and initial penetration, and directly proceeds to high-temperature baking. The specific steps are as follows: Steps (1), (2), and (3) are exactly the same as in Example 1.

[0086] Step (4), finishing and curing: After the nylon textile sheath is rolled with the second working fluid, it is immediately transferred to a 160 ℃ oven for 7 minutes to cure without pre-drying. The cured nylon textile sheath is then washed in 50 ℃ warm water for 2 minutes and finally dried in a 90 ℃ oven to constant weight to obtain the nylon textile sheath.

[0087] Application Examples Application Example 1 This application example 1 provides an application of a multifunctional nylon textile sheath in cable protection (specifically, a wiring harness protection device for automotive interiors and engine compartments). The specific implementation process is as follows: Step 1, Material Selection and Hot-Melt Cutting: Select the multifunctional nylon textile sheath prepared in Example 1 above. Based on the actual three-dimensional wiring data of the main wiring harness inside the engine compartment and dashboard of the car to be protected, use an automated hot-melt cutting device to cut the sheath into sections of the corresponding size. Hot-melt cutting can effectively seal the edges of the nylon cut, preventing fraying and wear during subsequent threading.

[0088] Step 2, Harness Threading and Node Covering: Using a pneumatic wire guide, smoothly thread the main harness and branch communication harnesses of the automotive multi-core insulated cable through one end of the multi-functional nylon textile sheath, ensuring they are fully contained within the sheath's inner cavity. For harness nodes with branches, use specialized scissors to create rounded exit holes at corresponding positions on the side of the sheath, smoothly guiding the branch harnesses out while ensuring the main sheath layer is flatly covered without excessive wrinkles.

[0089] Step 3, End sealing and heat shrinking fixation: At both ends of the wire harness sheath and at the branch lead-out nodes, insert halogen-free flame-retardant heat shrink tubing or wrap automotive-grade high-temperature resistant velour tape for heat shrinking and tightening fixation, ensuring that the sheath fits tightly with the internal cables and preventing axial slippage or loosening of the sheath during long-term vehicle operation.

[0090] The resulting automotive cable protection device demonstrates excellent comprehensive protection performance during actual vehicle installation and long-term service. On the one hand, the high-frequency vibration and high-temperature friction in the vehicle's engine compartment provide a strong barrier effect. The dense polydopamine underlayer constructed by this invention prevents the microscopic peeling and loss of the organophosphorus flame retardant in the nylon textile sheath, enabling the wire harness protection device to meet automotive interior combustion standards for an extended period and avoid fire hazards. On the other hand, when the vehicle is exposed to intense sunlight and the temperature inside the dashboard rises sharply, the hyperbranched cyclodextrin crosslinked network on the sheath surface can actively capture and firmly lock in volatile organic compounds such as benzene and aldehydes released from the nylon substrate, the underlayer flame retardant, and even the cable insulation rubber through host-guest inclusion. This significantly reduces odors inside the vehicle from the source, perfectly meeting the stringent low VOC emission limits required by modern automakers for automotive interior components.

[0091] Application Example 2 This application example 2 provides an application of a multifunctional nylon textile sheath in rail transit wiring harness protection devices (specifically, a protective sheath for concealed wiring harness groups in high-speed rail and urban light rail carriages). The specific implementation process is as follows: Step 1, Radial Appropriate Expansion and Pre-treatment: Select the multifunctional nylon textile sheath prepared in Example 2. Since the communication cables, control cables, and power supply cables in the bottom mezzanine and roof concealed works of rail transit are numerous, densely arranged, and have a large overall outer diameter, the multifunctional nylon textile sheath is first radially appropriately expanded and stretched using a mechanical flaring device to increase the inner cavity volume, facilitating the rapid introduction of large quantities of heavy-duty cables later.

[0092] Step two, cable bundling and self-retracting assembly: Various parallel cables within the high-speed train carriage chassis are combed and bundled together using a cable management comb; then, the bundled heavy-duty cables are threaded into the expanded multi-functional nylon textile sheath. Thanks to the excellent mechanical flexibility and high resilience of the nylon substrate, the sheath quickly and naturally retracts after the external flaring tension is removed, tightly and evenly adhering to the exterior of the massive cable bundle.

[0093] Step 3, cable tray installation and seismic installation: Lay the rail transit composite cable harness with sheaths in the metal cable trays on the side wall or chassis of the high-speed rail car, and use large-size flame-retardant nylon cable ties at specified intervals of 30-50 cm to firmly tie and fix it to the seismic support of the car frame.

[0094] In the enclosed and highly crowded environment of high-speed rail carriages, this rail transit wiring harness protection device plays a crucial role in providing both safety and environmental protection. Regarding fire safety, the outer layer of hyperbranched cyclodextrin with its multi-hydroxyl structure synergistically works with the underlying phosphorus-based flame retardant. Upon ignition from an electrical short circuit, it rapidly triggers a dual flame-retardant mechanism of "gas phase-condensed phase," generating a dense, heat-insulating char layer that effectively blocks the spread of fire within the long wiring ducts. In terms of environmental control, the high-speed rail carriage is a highly enclosed micro-circulation space. The durable three-dimensional adsorption network of the sheath's cross-linked layer not only does not release any harmful gases itself but also continuously absorbs and purifies odor molecules emitted from other non-metallic components within the interlayer. Simultaneously, the significantly increased wear resistance cycles after cross-linking and curing ensure that the sheath can withstand the long-term high-frequency friction generated during high-speed train operation and track changes, greatly extending the service life and maintenance cycle of the concealed wiring harness.

[0095] Application Example 3 This application example 3 provides an application of a multifunctional nylon textile sheath in sports equipment (specifically, a high abrasion-resistant protective jacket for outdoor rock climbing / adventure training safety ropes). The specific implementation process is as follows: Step 1, Preparation and pre-tensioning of the load-bearing inner core: Select a multi-strand twisted load-bearing rope woven from high molecular weight polyethylene fiber or aramid fiber with extremely high tensile strength as the core load-bearing inner core of the sports equipment, and place it on a constant tension device for pre-tensioning treatment to keep it straight.

[0096] Step 2, Tight Covering with Sleeves: The multifunctional nylon textile sheath prepared in Example 3 is selected as the wear-resistant and functional protective layer. A precision sleeve traction process is used to smoothly insert the pre-tensioned high-strength inner core from one end of the sheath; or, directly on a tubular braiding machine, using multifunctional nylon yarn prepared with the same liquid treatment process as in Example 3 as warp and weft yarns, high-density cross-weaving is performed directly around the stressed inner core, so that the multifunctional nylon textile sheath layer and the inner core achieve a tight nesting and binding structure.

[0097] Step 3, End bearing stitching and buckle assembly: At the bearing points at both ends of the prepared safety rope, use a heavy-duty industrial sewing machine with high-strength sewing thread to perform multiple "W"-shaped reinforcement knots and stitches; then, precisely assemble aerospace-grade aluminum metal safety buckles at the rope end eyelets, and put a thickened transparent heat-shrinkable protective sleeve on the outside of the rope end stitching connection for secondary reinforcement, thus producing a high-performance outdoor rock climbing safety rope.

[0098] This sports equipment demonstrates its multi-functional advantages in extremely harsh outdoor environments. During high-altitude rappelling or accidental falls, the safety rope inevitably experiences intense friction against rough rock faces, generating instantaneous high heat. The hyperbranched cyclodextrin cross-linked network on the outer side of the sheath of this invention not only greatly enhances the surface abrasion resistance and anti-pilling ability of the nylon fibers, but its unique dual flame-retardant mechanism also effectively prevents localized melting or ignition of the sheath caused by frictional heat, protecting the structural integrity of the internal aramid core and preventing rope breakage accidents. Furthermore, when athletes are in prolonged close contact with the skin, experience heavy hand sweating, or the rope is in a humid and hot environment, the green coating, cured with bio-based cross-linking agents such as citric acid and glycerin, is free of harmful heavy metals and formaldehyde residues. It is not only extremely skin-friendly but also effectively absorbs and locks in odors produced by the degradation of human sweat and free VOCs in the environment, demonstrating excellent safety protection.

[0099] Performance testing 1. Performance Testing Methods To fully verify the environmental friendliness, safety, and long-term service durability of the multifunctional nylon textile sheath prepared by this invention in practical applications, the following standard methods were used to characterize the comprehensive performance of the finished products obtained in Examples 1-6 and Comparative Examples 1-8: (1) Volatile organic compound (TVOC) release test: The TVOC rejection capacity of each group of samples was quantitatively analyzed by thermal desorption-gas chromatography-mass spectrometry (TDS-GC-MS). 2.0 g of sample was cut and placed in a sampling tube and sealed. It was desorbed at 90 °C for 30 min. The desorbed gas was introduced into the chromatography-mass spectrometry instrument by high-purity helium carrier gas for separation and quantification. The TVOC release (unit: μg) in the carbon chain length range of C6 to C16 was calculated and recorded. The lower the value, the stronger the physical locking ability of the sheath for volatile pollutants.

[0100] (2) Horizontal flame retardant performance test: Fix each group of samples horizontally on the metal bracket in the combustion chamber, ignite the free end of the sample with a Bunsen burner flame of 38 mm height for 15 s and then remove it, record the burning rate (mm / min) from the first mark. The sample is considered qualified if it self-extinguishes before the mark or the burning rate is less than 100 mm / min.

[0101] (3) Limiting Oxygen Index (LOI) test after water washing: In order to reflect the durability of the coating, each group of sheath samples were subjected to 10 consecutive standardized water washing cycles in warm water containing standard detergent and then dried. The minimum oxygen volume percentage required to maintain stable combustion in an oxygen-nitrogen mixed gas flow was then tested. This index can directly reflect the retention rate and long-term flame retardant ability of the bottom liquid flame retardant after water washing.

[0102] (4) Wear resistance test: The sheath sample is flattened and fixed on the grinding table of the wear tester. Under standard pressure, it is rubbed with standard wool friction cloth in multiple directions along the Lissajous trajectory. The number of friction cycles when two yarns on the sample surface break is recorded. The higher the number, the more significant the synergistic effect of the crosslinking coating on the mechanical strength of the substrate.

[0103] 2. Performance Test Results The four performance tests mentioned above were performed on the multifunctional nylon textile sheaths prepared in Examples 1-6 and Comparative Examples 1-8. The specific test results are shown in Table 1.

[0104] Table 1. Overall performance test results of each embodiment and comparative example

[0105] 3. Results Summary and Analysis As shown in Table 1, the multifunctional nylon textile sheaths prepared using the process of this invention (Examples 1 to 6) have achieved comprehensive performance improvements in terms of environmental protection, flame retardancy, and long-term physical durability. The TVOC emissions of each example were firmly controlled at extremely low levels. Not only did they meet all conventional horizontal combustion tests, but their limiting oxygen index remained consistently above 28.0% after 10 washes, and the wear resistance cycles all exceeded 26,000. This fully demonstrates that the polydopamine and hyperbranched cyclodextrin dual-coating system constructed in this application has extremely high interfacial bonding strength and structural density. While the hyperbranched cyclodextrin utilizes hydrophobic cavities to adsorb odor molecules, its three-dimensional network constructed through an acidic crosslinking system not only forms a gas-phase condensed-phase dual flame retardant mechanism with the underlying organophosphorus flame retardant, but also enhances the friction resistance and water washing erosion resistance of the nylon substrate surface, achieving high tolerance and performance stability under multi-dimensional process parameter adjustments.

[0106] Comparative Example 1, lacking a protective coating, experienced near-complete loss of its underlying flame retardant after washing, resulting in a limiting oxygen index (LOI) plummeting to 21.2% and extremely poor abrasion resistance. This confirms the technical bias of traditional external liquid flame retardants being highly susceptible to failure. Comparative Examples 2 and 6, lacking a polydopamine polymer layer under weakly alkaline conditions, not only suffered from the inability to firmly anchor the outer cyclodextrin, leading to a significant rebound in TVOC release, but also experienced flame retardant leakage and failure during washing due to the loss of a crucial physical barrier. While Comparative Example 3 maintained a high LIO after washing thanks to its polydopamine layer, the absence of a hyperbranched cross-linked network resulted in the complete loss of VOC retention capacity and the enhancement effect on outer abrasion resistance. Furthermore, the TVOC data of Comparative Example 4 deteriorated due to insufficient adsorption sites in the cavity caused by the use of ordinary cyclodextrin. Comparative Examples 5, 7, and 8 all suffered from the failure of the crosslinking system or improper curing conditions, which prevented the hyperbranched cyclodextrin from forming a complete and dense network structure. This directly led to microscopic peeling of the coating during water washing and friction testing, and the TVOC control rate, limiting oxygen index after washing, and number of wear resistance cycles all showed a decline.

[0107] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a multifunctional nylon textile sheath, characterized in that, Includes the following steps: Step (1): Dry the nylon textile sheath impregnated with organophosphorus liquid flame retardant at low temperature; Step (2): The nylon textile sheath treated in step (1) is completely immersed in the first working solution, and after the liquid-pinching rate is controlled by rolling, it is dried and washed in sequence. Step (3): Immerse the nylon textile sheath treated in step (2) in the second working solution and roll it again with a rolling mill to control the total liquid rate. Step (4): The nylon textile sheath treated in step (3) is pre-dried and then baked in sections, followed by washing in warm water and drying to obtain the multifunctional nylon textile sheath. The first working solution contains dopamine hydrochloride and has a pH of 8.5 to 9.0; the second working solution contains hyperbranched cyclodextrin and a cross-linking agent and has a pH of 4.0 to 5.

0.

2. The method for preparing a multifunctional nylon textile sheath according to claim 1, characterized in that, The first working solution comprises the following components: 3 g / L to 5 g / L of dopamine hydrochloride, 1 g / L to 2 g / L of penetrant and 1 g / L to 6 g / L of feel modifier; The second working solution comprises the following components: 10 g / L to 30 g / L of hyperbranched cyclodextrin, 12 g / L to 18 g / L of crosslinking agent, 5 g / L to 10 g / L of catalyst and 5 g / L to 10 g / L of β-cyclodextrin.

3. The method for preparing a multifunctional nylon textile sheath according to claim 2, characterized in that, The first working solution also contains an oxidant component, wherein the oxidant is selected from sodium percarbonate or hydrogen peroxide with a mass fraction of 25% to 35%; The penetrant is selected from nonionic fatty alcohol polyoxyethylene ether, wetting and penetrating agent JFC or AEO series fatty alcohol polyoxyethylene ether; The feel modifier is selected from amino silicone oil emulsion, polyethylene emulsion, or fatty acid amide; The pH of the first working solution is adjusted using a first pH adjuster, which is selected from borax buffer, triethanolamine or carbonate buffer.

4. The method for preparing a multifunctional nylon textile sheath according to claim 2, characterized in that, In the second working solution, the hyperbranched cyclodextrin is a BETA-cyclodextrin-epoxychloropropane copolymer with a molecular weight of 3000-8000; The catalyst is sodium hypophosphite; The second working solution is adjusted to pH using a second pH adjuster, which is selected from an aqueous solution of citric acid with a mass fraction of 8%-12% or a diluted acetic acid solution.

5. The method for preparing a multifunctional nylon textile sheath according to claim 4, characterized in that, In the second working solution, the crosslinking agent is selected from aqueous blocked isocyanate, ethylene glycol diglycidyl ether, or a combination of citric acid and glycerol; when the crosslinking agent is a combination of citric acid and glycerol, the mass concentration ratio of citric acid to glycerol in the second working solution is 1.5:1 to 2.5:

1.

6. A method for preparing a multifunctional nylon textile sheath according to claim 1, characterized in that, In step (1), the temperature of the low-temperature drying is 75 ℃~95 ℃, and the drying time is 2 min~4 min; In step (2), the immersion time in the first working solution is 5 min to 15 min, the immersion temperature is 35 ℃ to 45 ℃, and the liquid surface is kept slightly aerated during the process; the controlled liquid rolling rate is 60% to 80% of the mass of the sheath after treatment in step (1); the drying temperature is 80 ℃ to 90 ℃, and the drying time is 3 min to 5 min; the water washing is done with warm water at 35 ℃ to 40 ℃.

7. A method for preparing a multifunctional nylon textile sheath according to claim 1, characterized in that, In step (3), the immersion time in the second working fluid is 30 s to 50 s; the total molten liquid rate is controlled to be 60% to 90% of the mass of the sheath after treatment in step (1).

8. A method for preparing a multifunctional nylon textile sheath according to claim 1, characterized in that, In step (4), the pre-baking is performed at a temperature of 100 ℃~110 ℃ for 1 min~3 min; the segmented baking includes the following process: first, transfer to a temperature of 130 ℃~140 ℃ for 1 min~4 min to allow the crosslinking agent to initially penetrate and react, and then rapidly raise the temperature to 155 ℃~165 ℃ for 1 min~4 min to complete the curing; The washing conditions in warm water are 40 ℃ to 60 ℃ for 1 min to 3 min; the drying temperature is 75 ℃ to 90 ℃.

9. A multifunctional nylon textile sheath, characterized in that, The nylon textile sheath is prepared by any one of the preparation methods described in claims 1 to 8; the nylon textile sheath comprises a nylon substrate with an organophosphorus liquid flame retardant dried at low temperature, wherein the outer surface of the nylon substrate is sequentially and firmly grafted with a polydopamine layer formed by the self-polymerization of dopamine hydrochloride, and a hyperbranched cyclodextrin layer fixed on the surface of the polydopamine layer by a crosslinking reaction.

10. The application of the multifunctional nylon textile sheath as described in claim 9 in the manufacture of cable protection, sports equipment or rail transit wiring harness protection devices.

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