A method for preparing nylon fiber

Abstract

This invention discloses a method for preparing nylon fiber, belonging to the field of synthetic fiber modification technology. The preparation method includes the following steps: polyamino organosiloxane@CuS-PDA, nylon 66 salt, and nylon antioxidant are added to an extruder in a weight ratio of 1:10~20:0.01~0.02 for co-blending and granulation to obtain the high-strength antibacterial nylon fiber. This invention, through the synergistic effect of metal coordination and chemical covalent crosslinking, introduces nano-copper sulfide with photothermal antibacterial effect and polydopamine with good mechanical properties into the nylon fiber structure, thus obtaining high-strength antibacterial nylon fiber.

Description

[0001] This application is a divisional application of application number 2024117765451, filed on December 5, 2024, entitled "A high-strength antibacterial nylon fiber and its preparation method". Technical Field

[0002] This invention belongs to the field of synthetic fiber modification technology, specifically designing a method for preparing nylon fiber. Background Technology

[0003] Nylon fiber (PA), also known as polyamide fiber, is one of the earliest, most widely used, and high-performance synthetic fibers. Currently, nylon 6 and nylon 66 are the most commonly used. The macromolecular chain of nylon is linked by amide bonds (-CONH-). Its molecule consists of hydrophilic polar amide groups, methylene segments, terminal amino groups, and carboxyl groups. The amide bonds can form stable hydrogen bonds, resulting in intermolecular interactions and the formation of crystalline regions. Nylon possesses excellent abrasion resistance, elasticity, strength, toughness, and ease of dyeing, making it widely used in the textile industry (clothing, ropes, automotive interiors, and home furnishings such as curtains). However, nylon fibers are prone to static electricity, attracting dust to the fabric surface. Combined with human sweat, bacteria easily multiply on the fabric surface, potentially affecting human health. Since washing cannot effectively protect the surface of nylon fabrics from microbial contamination, there is a significant market demand for antibacterial nylon fabrics.

[0004] Antibacterial textiles can be classified into natural antibacterial textiles and artificial antibacterial textiles according to the source of the effective antibacterial components. Natural antibacterial textiles refer to textiles made from raw materials that grow in nature and have antibacterial properties, such as bamboo pulp fiber and ramie fiber. Artificial antibacterial textiles are textiles that are artificially endowed with antibacterial properties. At present, artificial antibacterial textiles are usually obtained by the following methods: (1) Blending spinning method, which mixes antibacterial agents with fiber raw materials and then produces antibacterial fibers through melt spinning; (2) Chemical grafting modification method, which grafts antibacterial groups onto the fiber surface through chemical bonds; (3) Composite spinning method, which spins antibacterial fibers and ordinary fibers together through a special spinneret; (4) Post-treatment method, which attaches antibacterial agents to the fibers.

[0005] Patent CN114672894A discloses an antibacterial nylon filament and its preparation process. This antibacterial nylon filament is made from an antibacterial masterbatch and a regular masterbatch. The antibacterial masterbatch is composed of graphene oxide / silver nanoparticle antibacterial agent, antioxidant, dispersant, and PA6 carrier resin, while the regular masterbatch is made from PA6 carrier resin. After graphene oxide acts as a carrier and combines with silver nanoparticles, the silver nanoparticles are mainly loaded on the graphene oxide sheets, stabilizing and protecting the silver nanoparticles. This improves the problem of easy oxidation and discoloration of silver nanoparticles to a certain extent. Simultaneously, the graphene oxide / silver nanoparticle composite material can reduce the release rate of silver nanoparticles, providing a slow-release effect and prolonging the action time of the antibacterial nylon filament, allowing it to maintain good antibacterial properties for a longer period.

[0006] Patent CN113417026A discloses a graphene high-insulation fiber and its preparation method. The graphene aerogel high-insulation composite nylon fiber prepared by this invention has numerous pores, which reduces heat loss by decreasing the surrounding airflow. Simultaneously, the infrared properties of graphene allow the fiber to absorb and release far-infrared rays, improving its high insulation performance. Furthermore, utilizing the antibacterial properties of graphene, the nylon fiber possesses antibacterial functions, protecting human health.

[0007] Patent CN115074857A discloses a cooling iodine antibacterial fiber and its preparation method. The invention first reacts silicon carbide nanowires and 3-chloropropyltrimethoxysilane, and then reacts them with sodium azide to obtain modified silicon carbide nanowires. Then, graphene oxide and 2-(4-ethynylphenyl)ethylene oxide are reacted to obtain modified graphene oxide. The modified silicon carbide nanowires, modified graphene oxide, and polyamide are extruded and melted to obtain silicon carbide nylon masterbatch. Iodine solution prepared by potassium iodide and iodine is reacted with soluble starch and polyvinyl alcohol to obtain composite gel. The composite gel and polyamide are extruded and melted to obtain PAT masterbatch. The silicon carbide nylon masterbatch and PAT masterbatch are combined and spun to obtain cooling iodine antibacterial fiber.

[0008] The aforementioned patent uses graphene, nano-silver, or graphene oxide as the core antibacterial raw materials. Although these materials have good antibacterial properties, graphene and graphene oxide are dark in color, making it difficult to change the fiber color through subsequent impregnation. Furthermore, due to the special nature of their nanostructures, graphene, graphene oxide, and nano-silver have high surface energy and are prone to agglomeration. When antibacterial nylon fibers are prepared by simply melt blending with nylon fiber materials without controlling the addition ratio and other core process parameters, uneven dispersion due to agglomeration can easily occur, which in turn reduces the antibacterial and toughness properties of the antibacterial nylon fibers.

[0009] Therefore, it is of great significance to design a high-strength antibacterial nylon fiber that avoids the aggregation phenomenon caused by the direct use of nano-antibacterial materials, which would negatively affect the nylon fiber. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention, through the synergistic effect of constructed metal coordination and chemical covalent crosslinking, introduces nano-copper sulfide with photothermal antibacterial effects and polydopamine with good mechanical properties into the nylon fiber structure, thereby obtaining high-strength antibacterial nylon fiber and solving the technical problems mentioned in the background art. Specifically, the technical solution of this invention includes the following:

[0011] One objective of this invention is to provide a method for preparing nylon fibers, the method comprising the following steps:

[0012] Polyamino organosiloxane@CuS-PDA, nylon 66 salt and nylon antioxidant are added to an extruder in a weight ratio of 1:10~20:0.01~0.02 to be co-blended and granulated to obtain the high-strength antibacterial nylon fiber.

[0013] Furthermore, the preparation method of the polyamino organosiloxane@CuS-PDA includes the following steps:

[0014] Monoamino-terminated organosiloxanes and alkanolamine compounds are mixed at a mass ratio of 1:0.05~0.1 and heated at 30℃~40℃ for 1h~2h to obtain polyamino-terminated organosiloxanes;

[0015] The polyamino-terminated organosiloxane, dopamine hydrochloride, carboxylic acid activator and carboxylic acid crosslinking agent are mixed and stirred in a mass ratio of 1:1~2:1.5~2.5:2~3 to form a reaction solution. The temperature of the reaction solution is controlled at 20℃~25℃ and the reaction is carried out for 20h~24h to obtain dopamine-modified polyamino organosiloxane.

[0016] The dopamine-modified polyamino organosiloxane, copper salt, and vulcanizing agent are mixed in a mass ratio of 1:0.1~0.2:0.01~0.05 and heated to 80℃~90℃ for vulcanization reaction for 2h~3h. After the vulcanization reaction is completed, the polyamino organosiloxane@CuS-PDA is obtained by alkaline catalytic crosslinking.

[0017] Furthermore, the monoamino-terminated organosiloxane includes 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

[0018] Furthermore, the alkanolamine compound includes ethanolamine or propanolamine.

[0019] Furthermore, the carboxylic acid activator is composed of EDC reagent and DMAP reagent in a 1:1 mass ratio.

[0020] Furthermore, the carboxylic acid crosslinking agent includes oxalic acid, and the structure of the carboxylic acid crosslinking agent needs to contain two carboxylic acid structures, which are used for amino amidation of dopamine hydrochloride and polyamino-terminated organosiloxane, respectively, thereby linking dopamine to polyamino-terminated organosiloxane.

[0021] Furthermore, the copper salt includes copper sulfate, copper chloride, or copper nitrate.

[0022] Furthermore, the sulfiding agent includes sodium sulfide nonahydrate, and the sulfiding agent may also be sulfur-containing hydrogen sulfide or sodium thiosulfate.

[0023] Furthermore, the conditions for the alkali-catalyzed crosslinking include a pH value of 8-9, a crosslinking temperature of 25℃-35℃, and a crosslinking time of 1h-3h.

[0024] Furthermore, the nylon 66 salt is prepared by heating a mixture of adipic acid and hexamethylenediamine.

[0025] Furthermore, the nylon antioxidant includes antioxidant BHT or antioxidant BHA.

[0026] The second objective of this invention is to provide a high-strength antibacterial nylon fiber prepared by a method for preparing high-strength antibacterial nylon fiber.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] This invention uses alkanolamine compounds as amino sources, leveraging both the alkaline catalytic effect of these compounds and the covalent bridging effect of the hydroxyl groups. Monoamino-terminated organosiloxanes are hydrolyzed under alkaline conditions, and through the condensation reaction between silanol and hydroxyl groups, an amino group is introduced to the other side of the monoamino-terminated organosiloxane, yielding a polyamino-terminated organosiloxane with multiple amino groups. Then, with the chemical crosslinking effect of a carboxyl crosslinking agent, the amino group on dopamine hydrochloride is bridged with the amino group of the polyamino-terminated organosiloxane through amidation to form dopamine-modified polyamino organosiloxanes. Next, leveraging the catechol hydroxyl groups on the dopamine structure to coordinate with metal ions, copper ions are fixed onto a dopamine-modified polyamino organosiloxane. The fixed copper ions are then deposited via sulfurization with a sulfurizing agent to form nano-copper sulfide with photothermal antibacterial effects. After sulfurization, cross-linking polymerization under the alkaline environment of dopamine further forms a polyamino organosiloxane@CuS-PDA with a strong cross-linked network structure and antibacterial properties. Finally, the polyamino organosiloxane@CuS-PDA is fed into an extruder with nylon 66 salt and nylon antioxidants for co-blending and granulation to obtain high-strength antibacterial nylon fiber. This invention creatively introduces nano-copper sulfide with photothermal antibacterial effects into nylon fiber through loading deposition, improving the antibacterial properties of nylon and reducing the possibility of negatively impacting nylon fiber from directly adding antibacterial, easily agglomerated nanomaterials. Subsequently, leveraging the excellent tensile strength and toughness of polydopamine (PDA) formed through dopamine polymerization, PDA is introduced into the nylon structure not only through covalent bonding but also by forming a cross-linked network structure with hydrogen bonds within the nylon fibers, thereby improving the toughness of the nylon fibers. Through the synergistic effect of metal coordination, covalent cross-linking, and hydrogen bonding, nylon fiber materials with high strength and antibacterial properties were prepared. Detailed Implementation

[0029] The technical solution of the present invention will be clearly and completely described below through embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Unless otherwise stated, all raw materials and reagents used in this invention are commercially available or can be prepared by known methods.

[0031] Preparation method of Nylon 66 salt: (It can be purchased commercially or prepared on-site as needed)

[0032] Adipic acid was dispersed in purified water using an ultrasonic cleaner to form a 50% (w / w) adipic acid suspension. Then, adipic acid was dissolved in purified water to form a 50% (w / w) hexamethylenediamine solution. The adipic acid suspension was placed in a temperature environment of 50±1℃, and then the hexamethylenediamine solution was added dropwise to mix and react. The reaction was stopped when the pH reached 8.0. The solution was then cooled to room temperature, filtered, and dried to obtain nylon 66 salt.

[0033] Preparation Example 1:

[0034] The preparation of polyamino organosiloxanes@CuS-PDA specifically includes the following processes:

[0035] Add 500g of 3-aminopropyltrimethoxysilane to a flask and add 200mL of purified water, stirring to disperse evenly (an ultrasonic cleaner can also be used to assist dispersion). Then add 25g of ethanolamine and mix to form a reaction solution. Place the reaction solution in a 30℃ water bath and heat for 1 hour. After the reaction, dialyze the mixture using a dialysis bag with a molecular weight cutoff of 500kDa, retaining the dialysate outside the dialysis bag. Purify the dialysate by vacuum distillation to obtain polyamino-terminated organosiloxanes.

[0036] 100g of polyamino-terminated organosiloxane and 100g of dopamine hydrochloride were mixed in 600mL of DMSO solvent and stirred until homogeneous. Then, 200g of oxalic acid, 75g of EDC reagent, and 75g of DMAP reagent were added, and the mixture was stirred continuously to form a reaction solution. The reaction solution was placed in a water bath at 20℃, and the stirring speed was set to 200 rpm. The reaction was carried out for 20 hours. After the reaction, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa to obtain the dialysate. The dialysate was then filtered to remove insoluble impurities, yielding the dopamine-modified polyamino organosiloxane.

[0037] 200g of dopamine-modified polyamino organosiloxane was dispersed in 1L of TE buffer (pH 7.0), and then 20g of copper nitrate was added and stirred for 30min to form a reaction solution. Subsequently, 2g of sodium sulfide was added to the reaction solution and stirred until homogeneous. The mixture was then heated to 80℃ for 2h. After heating, alkali was added to adjust the pH to 8.5±0.5, and crosslinking was continued at room temperature for 1h. After crosslinking, the mixture was filtered, washed with water, and dried to obtain polyamino organosiloxane@CuS-PDA.

[0038] Preparation Example 2:

[0039] The preparation of polyamino organosiloxanes@CuS-PDA specifically includes the following processes:

[0040] 500g of 3-aminopropyltrimethoxysilane was added to a flask, followed by 210mL of purified water and stirred until evenly dispersed (an ultrasonic cleaner can also be used to assist dispersion). Then, 30g of ethanolamine was added and stirred to form a reaction solution. The reaction solution was then placed in a water bath at 32°C and heated for 1 hour. After the reaction, the mixture was dialyzed using a dialysis bag with a molecular weight cutoff of 500kDa. The dialysate outside the dialysis bag was retained. The dialysate was purified by vacuum distillation to obtain polyamino-terminated organosiloxanes.

[0041] 100g of polyamino-terminated organosiloxane and 120g of dopamine hydrochloride were mixed in 800mL of DMSO solvent and stirred until homogeneous. Then, 220g of oxalic acid, 85g of EDC reagent, and 85g of DMAP reagent were added, and the mixture was stirred continuously to form a reaction solution. The reaction solution was placed in a water bath at 20℃, and the stirring speed was set to 200r / min. The reaction was carried out for 20h. After the reaction, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa to obtain the dialysate. The dialysate was then filtered to remove insoluble impurities, yielding the dopamine-modified polyamino organosiloxane.

[0042] 200g of dopamine-modified polyamino organosiloxane was dispersed in 1L of TE buffer (pH 7.0), and then 25g of copper nitrate was added and stirred for 30min to form a reaction solution. Subsequently, 4g of sodium sulfide was added to the reaction solution and stirred until homogeneous. The mixture was then heated to 80℃ for 2h. After heating, alkali was added to adjust the pH to 8.5±0.5, and crosslinking was continued at room temperature for 1h. After crosslinking, the mixture was filtered, washed with water, and dried to obtain polyamino organosiloxane@CuS-PDA.

[0043] Preparation Example 3:

[0044] The preparation of polyamino organosiloxanes@CuS-PDA specifically includes the following processes:

[0045] 500g of 3-aminopropyltrimethoxysilane was added to a flask, followed by 220mL of purified water and stirred until evenly dispersed (an ultrasonic cleaner can also be used to assist dispersion). Then, 35g of ethanolamine was added and stirred to form a reaction solution. The reaction solution was then placed in a water bath at 34°C and heated for 1.5 hours. After the reaction, the mixture was dialyzed using a dialysis bag with a molecular weight cutoff of 500kDa. The dialysate outside the dialysis bag was retained. The dialysate was purified by vacuum distillation to obtain polyamino-terminated organosiloxanes.

[0046] 100g of polyamino-terminated organosiloxane and 140g of dopamine hydrochloride were mixed in 800mL of DMSO solvent and stirred until homogeneous. Then, 240g of oxalic acid, 95g of EDC reagent, and 95g of DMAP reagent were added, and the mixture was stirred continuously to form a reaction solution. The reaction solution was placed in a water bath at 20℃, and the stirring speed was set to 250r / min. The reaction was started and the reaction time was set to 22h. After the reaction was completed, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa to obtain the dialysate. The dialysate was then filtered to remove insoluble impurities, yielding the dopamine-modified polyamino organosiloxane.

[0047] 200g of dopamine-modified polyamino organosiloxane was dispersed in 1L of TE buffer (pH 7.0), and then 30g of copper chloride was added and stirred for 35min to form a reaction solution. Subsequently, 6g of sodium sulfide was added to the reaction solution and stirred until homogeneous. The mixture was then heated to 85℃ for 2.5h. After heating, alkali was added to adjust the pH to 8.5±0.5, and crosslinking was continued at room temperature for 2h. After crosslinking, the mixture was filtered, washed with water, and dried to obtain polyamino organosiloxane@CuS-PDA.

[0048] Preparation Example 4:

[0049] The preparation of polyamino organosiloxanes@CuS-PDA specifically includes the following processes:

[0050] 500g of 3-aminopropyltriethoxysilane was added to a flask, followed by 230mL of purified water and stirred until evenly dispersed (an ultrasonic cleaner can also be used to assist dispersion). Then, 40g of propanolamine was added and stirred to form a reaction solution. The reaction solution was then placed in a water bath at 36°C and heated for 1.5 hours. After the reaction, the mixture was dialyzed using a dialysis bag with a molecular weight cutoff of 500kDa. The dialysate outside the dialysis bag was retained. The dialysate was purified by vacuum distillation to obtain polyamino-terminated organosiloxanes.

[0051] 100g of polyamino-terminated organosiloxane and 160g of dopamine hydrochloride were mixed in 900mL of DMF solvent and stirred until homogeneous. Then, 260g of oxalic acid, 105g of EDC reagent, and 105g of DMAP reagent were added, and the mixture was stirred continuously to form a reaction solution. The reaction solution was placed in a water bath at 25℃, and the stirring speed was set to 250r / min. The reaction was started and the reaction time was set to 22h. After the reaction was completed, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa to obtain the dialysate. The dialysate was then filtered to remove insoluble impurities, yielding the dopamine-modified polyamino organosiloxane.

[0052] 200g of dopamine-modified polyamino organosiloxane was dispersed in 1L of TE buffer (pH 7.5), and then 35g of copper chloride was added and stirred for 35min to form a reaction solution. Subsequently, 8g of sodium sulfide was added to the reaction solution and stirred until homogeneous. The mixture was then heated to 85℃ for 2.5h. After heating, alkali was added to adjust the pH to 8.5±0.5, and crosslinking was continued at room temperature for 2h. After crosslinking, the mixture was filtered, washed with water, and dried to obtain polyamino organosiloxane@CuS-PDA.

[0053] Preparation Example 5:

[0054] The preparation of polyamino organosiloxanes@CuS-PDA specifically includes the following processes:

[0055] 500g of 3-aminopropyltriethoxysilane was added to a flask, and 240mL of purified water was added and stirred until evenly dispersed (an ultrasonic cleaner can also be used to assist dispersion). Then, 45g of propanolamine was added and stirred to form a reaction solution. The reaction solution was then placed in a water bath at 38°C and heated for 2 hours. After the reaction, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa. The dialysate outside the dialysis bag was retained. The dialysate was purified by vacuum distillation to obtain polyamino-terminated organosiloxanes.

[0056] 100g of polyamino-terminated organosiloxane and 180g of dopamine hydrochloride were mixed in 1L of DMF solvent and stirred until homogeneous. Then, 280g of oxalic acid, 115g of EDC reagent, and 115g of DMAP reagent were added, and the mixture was stirred continuously to form a reaction solution. The reaction solution was placed in a water bath at 25℃, and the stirring speed was set to 300 rpm. The reaction was started and the reaction time was set to 24h. After the reaction was completed, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa to obtain the dialysate. The dialysate was then filtered to remove insoluble impurities, yielding the dopamine-modified polyamino organosiloxane.

[0057] 200g of dopamine-modified polyamino organosiloxane was dispersed in 1L of TE buffer (pH 7.5), and then 40g of copper sulfate was added and stirred for 40min to form a reaction solution. Subsequently, 10g of sodium sulfide was added to the reaction solution and stirred until homogeneous. The mixture was then heated to 90℃ for 3h. After heating, alkali was added to adjust the pH to 8.5±0.5, and crosslinking was continued at room temperature for 3h. After crosslinking, the mixture was filtered, washed with water, and dried to obtain polyamino organosiloxane@CuS-PDA.

[0058] Preparation Example 6:

[0059] The preparation of polyamino organosiloxanes@CuS-PDA specifically includes the following processes:

[0060] 500g of 3-aminopropyltriethoxysilane was added to a flask and 250mL of purified water was added and stirred until evenly dispersed (an ultrasonic cleaner can also be used to assist dispersion). Then, 50g of propanolamine was added and stirred to form a reaction solution. The reaction solution was then placed in a water bath at 40℃ and heated for 2 hours. After the reaction, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa. The dialysate outside the dialysis bag was retained. The dialysate was purified by vacuum distillation to obtain polyamino-terminated organosiloxanes.

[0061] 100g of polyamino-terminated organosiloxane and 200g of dopamine hydrochloride were mixed in 1L of DMF solvent and stirred until homogeneous. Then, 300g of oxalic acid, 125g of EDC reagent, and 125g of DMAP reagent were added, and the mixture was stirred continuously to form a reaction solution. The reaction solution was placed in a water bath at 25℃, and the stirring speed was set to 300 rpm. The reaction was started and the reaction time was set to 24h. After the reaction was completed, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa to obtain the dialysate. The dialysate was then filtered to remove insoluble impurities, yielding the dopamine-modified polyamino organosiloxane.

[0062] 200g of dopamine-modified polyamino organosiloxane was dispersed in 1L of TE buffer (pH 7.5), and then 40g of copper sulfate was added and stirred for 40min to form a reaction solution. Subsequently, 10g of sodium sulfide was added to the reaction solution and stirred until homogeneous. The mixture was then heated to 90℃ for 3h. After heating, alkali was added to adjust the pH to 8.5±0.5, and crosslinking was continued at room temperature for 3h. After crosslinking, the mixture was filtered, washed with water, and dried to obtain polyamino organosiloxane@CuS-PDA.

[0063] Preparation Example 7:

[0064] The preparation of polyamino organosiloxanes@CuS-PDA specifically includes the following processes:

[0065] 500g of 3-aminopropyltriethoxysilane was added to a flask and 250mL of purified water was added and stirred until evenly dispersed (an ultrasonic cleaner can also be used to assist dispersion). Then, 50g of propanolamine was added and stirred to form a reaction solution. The reaction solution was then placed in a water bath at 40℃ and heated for 2 hours. After the reaction, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa. The dialysate outside the dialysis bag was retained. The dialysate was purified by vacuum distillation to obtain polyamino-terminated organosiloxanes.

[0066] 100g of polyamino-terminated organosiloxane and 200g of dopamine hydrochloride were mixed in 1L of DMF solvent and stirred until homogeneous. Then, 300g of oxalic acid, 125g of EDC reagent, and 125g of DMAP reagent were added, and the mixture was stirred continuously to form a reaction solution. The reaction solution was placed in a water bath at 25℃, and the stirring speed was set to 300 rpm. The reaction was started and the reaction time was set to 24h. After the reaction was completed, the mixture was dialyzed through a dialysis bag with a molecular weight cutoff of 500kDa to obtain the dialysate. The dialysate was then filtered to remove insoluble impurities, yielding the dopamine-modified polyamino organosiloxane.

[0067] 200g of dopamine-modified polyamino organosiloxane was dispersed in 1L of TE buffer (pH 7.5), and the pH was adjusted to 8.5±0.5 with alkali. Crosslinking was continued for 3h at room temperature with stirring. After crosslinking, the product was filtered, washed with water, and dried to obtain polyamino organosiloxane@CuS-PDA.

[0068] Example 1:

[0069] The preparation of a high-strength antibacterial nylon fiber specifically includes the following process:

[0070] Five parts by weight of the polyamino organosiloxane @CuS-PDA obtained in Preparation Example 1, 50 parts by weight of nylon 66 salt, and 0.05 parts by weight of antioxidant BHT were mixed and added to an extruder. The mixture was then plasticized and blended at 210°C and 100 r / min for 70 min. The temperature was then raised to 260°C, and the mixture was melt-blended at 150 r / min and 0.5 MPa for 10 min. The resulting product was then extruded and granulated to obtain high-strength antibacterial nylon fiber.

[0071] Example 2:

[0072] The preparation of a high-strength antibacterial nylon fiber specifically includes the following process:

[0073] Five parts by weight of the polyamino organosiloxane @CuS-PDA obtained in Preparation Example 2, 60 parts by weight of nylon 66 salt, and 0.05 parts by weight of antioxidant BHT were mixed and added to an extruder. The mixture was then plasticized and blended at 210°C and a rotation speed of 110 r / min for 80 min. The temperature was then raised to 260°C, and the mixture was melt-blended at a rotation speed of 150 r / min and a pressure of 0.6 MPa for 12 min. Subsequently, the mixture was extruded and granulated to obtain high-strength antibacterial nylon fiber.

[0074] Example 3:

[0075] The preparation of a high-strength antibacterial nylon fiber specifically includes the following process:

[0076] Five parts by weight of the polyamino organosiloxane @CuS-PDA obtained in Preparation Example 3, 70 parts by weight of nylon 66 salt, and 0.05 parts by weight of antioxidant BHT were mixed and added to an extruder. The mixture was then plasticized and blended at 220°C and 120 r / min for 90 min. The temperature was then raised to 270°C, and the mixture was melt-blended at 200 r / min and 0.7 MPa for 14 min. The resulting product was then extruded and granulated to obtain high-strength antibacterial nylon fiber.

[0077] Example 4:

[0078] The preparation of a high-strength antibacterial nylon fiber specifically includes the following process:

[0079] Five parts by weight of the polyamino organosiloxane @CuS-PDA obtained in Preparation Example 4, 80 parts by weight of nylon 66 salt, and 0.1 parts by weight of antioxidant BHA were mixed and added to an extruder. The mixture was then plasticized and blended at 220°C and a rotation speed of 130 r / min for 100 min. The temperature was then raised to 270°C, and the mixture was melt-blended at a rotation speed of 200 r / min and a pressure of 0.8 MPa for 16 min. Subsequently, the mixture was extruded and granulated to obtain high-strength antibacterial nylon fiber.

[0080] Example 5:

[0081] The preparation of a high-strength antibacterial nylon fiber specifically includes the following process:

[0082] Five parts by weight of the polyamino organosiloxane @CuS-PDA obtained in Preparation Example 5, 90 parts by weight of nylon 66 salt, and 0.1 parts by weight of antioxidant BHA were mixed and added to an extruder. The mixture was then plasticized and blended at 230°C and a rotation speed of 140 r / min for 110 min. The temperature was then raised to 280°C, and the mixture was melt-blended at a rotation speed of 250 r / min and a pressure of 0.9 MPa for 18 min. Subsequently, the mixture was extruded and granulated to obtain high-strength antibacterial nylon fiber.

[0083] Example 6:

[0084] The preparation of a high-strength antibacterial nylon fiber specifically includes the following process:

[0085] Five parts by weight of the polyamino organosiloxane @CuS-PDA obtained in Preparation Example 6, 100 parts by weight of nylon 66 salt, and 0.1 parts by weight of antioxidant BHA were mixed and added to an extruder. The mixture was then plasticized and blended at 230°C and 150 r / min for 110 min. The temperature was then raised to 280°C, and the mixture was melt-blended at 250 r / min and 1 MPa for 20 min. The resulting product was then extruded and granulated to obtain high-strength antibacterial nylon fiber.

[0086] Comparative Example 1:

[0087] The preparation of a high-strength antibacterial nylon fiber specifically includes the following process:

[0088] Five parts by weight of the polyamino organosiloxane@CuS-PDA obtained in Preparation Example 7, 100 parts by weight of nylon 66 salt, 0.1 parts by weight of antioxidant BHA, and 5 parts by weight of nano-copper sulfide were mixed and added to an extruder. The mixture was then plasticized and blended at 230°C and a rotation speed of 150 r / min for 110 min. The temperature was then raised to 280°C, and the mixture was melt-blended at a rotation speed of 250 r / min and a pressure of 1 MPa for 20 min. The resulting product was then extruded and granulated to obtain high-strength antibacterial nylon fiber.

[0089] At room temperature, the viable bacterial count is 1×10⁻⁶. 7 ~1×10 8 CFU / mL of Escherichia coli and Staphylococcus aureus bacterial suspensions were dropped onto the surface of the high-strength antibacterial nylon fibers obtained in Examples 1-6 and Comparative Example 1, and then transferred to an NIR laser emitter with a wavelength of 1100 nm at a firing rate of 0.7 W / cm². 2 The surface of the high-strength antibacterial nylon fiber was irradiated with a certain power for 10 minutes, and the surface temperature was recorded using a temperature measuring instrument. After treatment, the surface of the high-strength antibacterial nylon fiber was rinsed with PBS buffer solution. 100 µL of the rinsing solution was taken and spread on LB solid medium. Finally, it was incubated in a constant temperature incubator at 37℃ for 24 hours, and the bacterial count was recorded by plate counting method to calculate the sterilization rate. The results are shown in Table 1 below.

[0090] Table 1

[0091]

[0092] Using an electronic universal testing machine, the high-strength antibacterial nylon fibers obtained in Examples 1-6 and Comparative Example 1 were stretched at a stretching rate of 5 mm / min according to ISO 527-1-2012 "Determination of tensile properties of plastics". The tensile strength and elongation at break were calculated, and the results are shown in Table 2 below.

[0093] Table 2

[0094]

[0095] From Tables 1 and 2 above, we can conclude that:

[0096] (1) In Examples 1-6, the present invention introduces nano-copper sulfide with photothermal antibacterial effect into nylon fibers through metal coordination and chemical deposition to improve the antibacterial properties of nylon. Subsequently, by utilizing the good tensile strength and toughness of polydopamine (PDA) formed by dopamine polymerization, a cross-linked network structure with hydrogen bonding is formed inside the nylon fiber through covalent bonding and hydrogen bonding, thereby improving the mechanical properties of the nylon fiber.

[0097] (2) As can be seen from Comparative Example 1, although polyamino organosiloxanes @CuS-PDA can enter nylon fiber materials through hydrogen bonding and covalent cross-linking, due to the agglomeration characteristics of nano copper oxide, it only relies on physical adsorption such as van der Waals forces to bind to nylon fibers, resulting in low binding force and easy uneven dispersion on nylon fibers, low tensile strength and elongation at break, decreased mechanical properties, and poor antibacterial properties.

[0098] The embodiments described above provide a detailed explanation of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for preparing nylon fiber, characterized in that, The preparation method includes the following steps: Polyamino organosiloxane@CuS-PDA, nylon 66 salt and nylon antioxidant are added to an extruder in a weight ratio of 1:10~20:0.01~0.02 and then blended and granulated to obtain the nylon fiber; The preparation method of the polyamino organosiloxane@CuS-PDA includes the following steps: Monoamino-terminated organosiloxanes and alkanolamine compounds are mixed at a mass ratio of 1:0.05~0.1 and heated at 30℃~40℃ for 1h~2h to obtain polyamino-terminated organosiloxanes; The polyamino-terminated organosiloxane, dopamine hydrochloride, carboxylic acid activator and carboxylic acid crosslinking agent are mixed and stirred in a mass ratio of 1:1~2:1.5~2.5:2~3 to form a reaction solution. The temperature of the reaction solution is controlled at 20℃~25℃ and the reaction is carried out for 20h~24h to obtain dopamine-modified polyamino organosiloxane. The dopamine-modified polyamino organosiloxane, copper salt, and vulcanizing agent are mixed in a mass ratio of 1:0.1~0.2:0.01~0.05 and heated to 80℃~90℃ for vulcanization reaction for 2h~3h. After the vulcanization reaction is completed, the polyamino organosiloxane@CuS-PDA is obtained by alkaline catalytic crosslinking. The monoamino-terminated organosiloxane is 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane; The alkanolamine compound includes ethanolamine or propanolamine, the carboxylic acid crosslinking agent includes oxalic acid, and the copper salt includes copper sulfate, copper chloride, or copper nitrate. The vulcanizing agent includes sodium sulfide nonahydrate, and the conditions for alkaline-catalyzed crosslinking include a pH value of 8-9, a crosslinking temperature of 25℃-35℃, and a crosslinking time of 1h-3h.

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