Antibacterial master batch for melt spinning of chinlon 6 and preparation method of antibacterial master batch

Abstract

The invention provides an antibacterial master batch for melt spinning of chinlon 6 and a preparation method thereof, the antibacterial master batch comprises chinlon 6 resin slices, a long carbon chain alkyl glycidyl ether modified guanidine salt polymer anti-harmful microorganism material, a main antioxidant, an auxiliary antioxidant, a lubricant and a dispersing agent, and the preparation method comprises the following steps: uniformly mixing the components in proportion, and adding into a twin-screw extruder; and under the protection of inert gas, carrying out melt blending on the blended materials through a twin-screw extruder, and granulating to obtain the antibacterial master batch for melt spinning of chinlon 6. The antibacterial master batch for melt-spinning chinlon 6 is used for antibacterial modification of melt-spinning chinlon 6 fibers, the addition amount of the antibacterial master batch is 2-10% of the mass of a chinlon 6 resin slice base material, and the prepared antibacterial modified melt-spinning chinlon 6 has the advantages of lasting antibacterial performance, high efficiency, broad spectrum, washing resistance, dissolution resistance and the like.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to an antibacterial masterbatch for melt-spun nylon 6 and its preparation method. Background Technology

[0002] Polyamide 6 (Nylon 6) is a polymer containing amide groups in its main chain. Polyamide 6 fiber (nylon 6) was the first fiber to be industrially produced in the world, and it is commonly known as nylon 6 in my country. Nylon 6 has excellent abrasion resistance, alkali resistance, moisture absorption, elasticity, and fatigue resistance, and is widely used in clothing, home textiles, and industrial textiles. However, ordinary nylon 6 textiles do not have antibacterial properties, but bacteria are widespread in the human environment and closely related to people's lives, thus having a significant impact on people's production and daily life. Textiles are ubiquitous in daily life, making them a significant medium for the direct or indirect transmission of bacteria in human life. This allows various pathogens to proliferate and multiply on the surface of ordinary nylon 6 textiles without antibacterial properties, leading to the following three main adverse effects: 1. Pathogenic bacteria on nylon 6 textiles multiply rapidly after obtaining nutrients, metabolizing or decomposing various volatile compounds with irritating odors, causing the nylon 6 textiles contaminated with bacteria to produce various unpleasant smells, affecting human hygiene; 2. During the processing of nylon 6 textiles, small amounts of finishing agents and other reagents may adhere to the textiles. These substances become a nutrient source for pathogens, allowing them to multiply rapidly. The various metabolic products of pathogens may damage the molecular chains within the fibers, causing the nylon 6 textiles to experience deterioration in mechanical properties and discoloration; 3. Pathogenic bacteria can exist in the human body through the skin, respiratory tract, etc., adversely affecting human health.

[0003] Therefore, by using physical or chemical methods to endow ordinary nylon 6 textiles with certain antibacterial properties, the aim is to inhibit the proliferation of pathogenic bacteria or kill pathogenic bacteria, thereby effectively reducing the damage of pathogenic bacteria to nylon 6 textiles and the harm to human hygiene and health. Currently, antibacterial functionalization technologies for nylon 6 can be broadly divided into two categories: fiber modification technology and fiber / fabric finishing technology. Fiber modification refers to adding antibacterial auxiliaries during polymerization or spinning to produce nylon 6 with antibacterial functions. Fiber / fabric finishing involves coating or impregnating nylon 6 or fabrics with antibacterial components. Compared to the former, the former produces products with longer-lasting antibacterial effects and better wash resistance, while the latter's wash resistance needs improvement. Furthermore, the latter generates more waste during the entire production process. Therefore, fiber modification technology is currently the more commonly used antibacterial functionalization technology for nylon 6.

[0004] Currently, antibacterial nylon 6 is mainly produced using fiber modification technology through blend spinning. This method can be further divided into two approaches: the antibacterial masterbatch method and the adhesion method, with the former being more convenient. Antibacterial agents applicable to the blend spinning method for preparing antibacterial melt-spun nylon 6 are mainly classified into inorganic and organic types. Inorganic antibacterial agents primarily include metals and metal oxides. Inorganic metal antibacterial agents are mainly produced by introducing metal ions such as silver, copper, and zinc onto inorganic carriers such as phosphates and silicates. Inorganic metal oxide antibacterial agents mainly include titanium oxide, zinc oxide, cuprous oxide, etc., and generally use ceramics as a carrier. The main advantage of inorganic antibacterial agents is their good heat resistance, but their disadvantages include higher price, delayed antibacterial effect, and easy aggregation in the matrix resin. Among these, silver-based substances have the strongest bactericidal ability, but silver ions are prone to discoloration and have slight toxicity. The safety of silver ion antibacterial products is highly controversial in Europe and the United States. Organic antibacterial agents mainly include quaternary ammonium salts, quaternary phosphate salts, phenols, pyridines, alcohols, aldehydes, guanidines, and imidazoles. Organic antibacterial agents have high bactericidal efficiency and require less addition, but generally have disadvantages such as low heat resistance and easy precipitation. Among them, antibacterial agents containing guanidine salt polymers are considered to have great development potential. Guanidine salt polymers are cationic polyelectrolytes with guanidine salt groups. They mainly inhibit the action of harmful microbial cell lysis enzymes by forming electrostatic adsorption between the cations in the molecule and the anionic sites on the surface of bacterial cells, thereby deforming the cell surface structure and destroying the cell membrane, thus achieving the effect of inhibiting and disinfecting microorganisms. Guanidine salt polymers have the advantages of good water solubility, photothermal stability, high efficiency and broad spectrum of antibacterial properties, safety, low toxicity, non-irritation, no bacterial resistance, non-volatile, free of heavy metals and phenols, non-corrosive to various treated surfaces, and environmental friendliness. They have been widely used in medical disinfection, food and other daily necessities sterilization and disinfection. Since the guanidine group is a hydrophilic group, most guanidine salt polymers are highly water-soluble. Currently, they are mainly used in the form of aqueous solutions of guanidine salt polymers for surface disinfection of products and post-antibacterial finishing of textiles. However, when guanidine salt polymers are blended and modified with plastics or rubber, the products will gradually lose their antibacterial properties due to their poor water resistance because of their water solubility.

[0005] Therefore, how to improve the water resistance of polymer products containing guanidine salt polymers while maintaining the advantages of guanidine salt polymers in resisting harmful microorganisms is a topic worthy of research. Thus, it is necessary to develop a melt-spun nylon 6 antibacterial masterbatch based on guanidine salt polymers that has high antibacterial efficiency, is resistant to leaching, has a long-lasting antibacterial effect, is safe, and has broad market prospects. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention provides an antibacterial masterbatch for melt-spun nylon 6 and its preparation method. This antibacterial masterbatch for melt-spun nylon 6 is used to manufacture nylon 6 fiber products with antibacterial functions. The addition amount is 2% to 10% of the melt-spun fiber-grade nylon 6 chip base material. The prepared antibacterial melt-spun nylon 6 fiber products have excellent antibacterial properties, water resistance, long-lasting antibacterial effect, and safety.

[0007] The purpose of this invention is to provide an antibacterial masterbatch for melt-spun nylon 6, comprising the following components in parts by weight: 100 portions of nylon 6 resin chips; 10-30 parts of long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material; 0.2~1.0 parts of the main antioxidant; 0.2-1.0 parts of auxiliary antioxidant; Lubricant 0.2~1.0 parts; Dispersant 0.2~1.0 parts.

[0008] The above-mentioned long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material includes the following components in the following ratio: the mass ratio of long-chain glycidyl ether to guanidine salt polymer is 1:0.5-2.

[0009] Preferably, the long-chain alkyl glycidyl ethers include at least one of C12-14-alkyl glycidyl ether, C16-alkyl glycidyl ether, and C18-alkyl glycidyl ether.

[0010] The guanidine salt polymers include at least one of polyhexamethylene guanidine hydrochloride, polyhexamethylene biguanidine hydrochloride, polyhexamethylene guanidine propionate, polyhexamethylene biguanidine propionate, polyhexamethylene guanidine nitrate, polyhexamethylene biguanidine nitrate, polyhexamethylene guanidine phosphate, polyhexamethylene biguanidine phosphate, polyhexamethylene guanidine carbonate, and polyhexamethylene biguanidine carbonate.

[0011] A method for preparing a long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material includes the following steps: Step (1): Under the protection of an inert gas, the guanidine salt polymer and anhydrous dimethylformamide (DMF) are added to the ultrasonic reactor and mixed to prepare a guanidine salt polymer solution with a mass concentration of 5% to 10%. Triethylamine is slowly added dropwise to the ultrasonic reactor to adjust the pH value of the guanidine salt polymer solution to 8.0 to 9.5. After stirring at room temperature for 1 to 2 hours, 2,4,6-tris(dimethylaminomethyl)phenol and butylhydroxytoluene are added to the reaction system. Step (2): Mix long-chain alkyl glycidyl ether with anhydrous dimethylformamide to prepare a long-chain alkyl glycidyl ether solution with a mass concentration of 20%~40%, and preheat it to 50~60℃. Then slowly add it dropwise into the ultrasonic reactor of step (1). During the dropwise addition, the ultrasonic generator of the ultrasonic reactor is started at the same time. After the dropwise addition is completed, under the protection of inert gas, the temperature is raised to 50℃~60℃ and the reaction is continuously stirred for 4~16 hours. Step (3): After the reaction in step (2) is completed, the reaction system is cooled to room temperature, a small amount of glacial acetic acid is added to adjust the pH value to neutral, the reaction solution is slowly poured into 5 times the volume of cold methanol, and the product is stirred vigorously to precipitate as a white flocculent precipitate. The product is then filtered using a Buchner funnel and the precipitate is collected. The precipitate is dispersed in a 1:1 mass ratio acetone / ethanol mixture and ultrasonically washed for 10 minutes. This is repeated 3 times until the washing solution is transparent. The washed precipitate is placed in a vacuum drying oven and dried at 50°C for 12 hours to obtain a white to light yellow long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material solid powder product.

[0012] Preferably, in the above preparation method, 2,4,6-tris(dimethylaminomethyl)phenol is selected from DMP-30, and its amount is 0.1% to 3% of the mass of long-chain alkyl glycidyl ether; butyl hydroxytoluene is selected from BHT, and its amount is 0.1% to 0.3% of the mass of long-chain alkyl glycidyl ether.

[0013] This invention relates to the preparation of a long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material. Using DMF as a solvent and a system pH of 8.0–9.5, and with DMP-30 as a catalyst, the epoxy groups of the long-chain alkyl glycidyl ether undergo a grafting reaction with the secondary amine groups of the guanidine salt polymer backbone, and also react with the primary amine groups at the chain ends of the guanidine salt polymer. This introduces the hydrophobic long-chain alkyl group into the water-soluble guanidine salt polymer molecular chain, thus hydrophobically modifying the water-soluble guanidine salt polymer and preparing the long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material.

[0014] Furthermore, the primary antioxidant is selected from at least one of antioxidant 1098 and antioxidant 1330, the secondary antioxidant is selected from at least one of antioxidant 168 and antioxidant 626, the lubricant is selected from ethylene bis-stearamide (EBS), and the dispersant is selected from polyethylene wax.

[0015] The present invention also aims to provide a method for preparing antibacterial masterbatch for melt-spun nylon 6. This method employs a parallel-co-rotating twin-screw extruder with nitrogen protection during the production process. The extruder consists of thirteen barrel sections. The method for preparing the antibacterial masterbatch includes the following steps: pre-drying nylon 6 resin chips at 100°C with hot air for 24 hours; then mixing the dried nylon 6 resin chips with a long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material, a primary antioxidant, a secondary antioxidant, a lubricant, and a dispersant in a certain proportion until homogeneous, and then adding the mixture to the hopper of the twin-screw extruder. The hopper is protected by nitrogen gas. The temperature of each barrel of the twin-screw extruder is set to 180~250℃, and the screw speed is 200~350rpm. Nitrogen gas is introduced into the barrel sections 2~4, 6~8, and 10~11 from the feed inlet through the nitrogen gas inlet at the center of the top of the barrel for protection. Vacuum degassing is performed by opening vacuum exhaust chambers on the barrel sections 5, 9, and 12 from the feed inlet. The blended material is melt-blended by the twin-screw extruder and then granulated by an air-cooled die pelletizing device. Nitrogen air cooling is used to protect the die head, and antibacterial masterbatch for melt-spun nylon 6 is obtained.

[0016] The present invention also aims to provide a twin-screw extruder for preparing the above-mentioned antibacterial masterbatch, which is a parallel co-rotating meshing twin-screw extruder. The extruder barrel is divided into several sections, one of which or several consecutive sections form several groups. The extruder is equipped with an inert gas protection system, including an inert gas inlet pipe. The barrel is sequentially provided with an inert gas inlet component and a vacuum regulating gas outlet component. The cover plate of the extruder hopper is provided with an inert gas inlet component and a gas outlet component. The inert gas inlet component is connected to the inert gas inlet pipe. An inert gas air cooling component is also provided at the die of the extruder head.

[0017] The inert gas inlet assembly includes a valve, a pressure regulating assembly, and a flow regulating assembly.

[0018] In use, inert gas enters the cylinder through the inert gas inlet component and is discharged through the gas outlet component. The blended material is melt-blended and granulated after being processed by a twin-screw extruder. Inert gas protection is achieved at the die head through an inert gas air-cooling component, thus realizing inert gas protection for the material during the production process.

[0019] The present invention also aims to provide a melt-spun nylon 6, wherein the amount of antibacterial masterbatch added is 2 to 10% of the mass of nylon 6 resin chip base material.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The antibacterial masterbatch for melt-spun nylon 6 of this application has good spinnability, good antibacterial efficiency and long-lasting effect, water resistance, safety and silver-free properties. It can be used to prepare melt-spun nylon 6 products with antibacterial function. The addition amount is 2~10% of the melt-spun nylon 6 chip base material. The prepared antibacterial melt-spun nylon 6 products have the advantages of safety, broad spectrum, water resistance, and long-lasting antibacterial effect, and have broad market prospects and commercial value. (2) The preparation method of the antibacterial masterbatch for melt-spun nylon 6 in this application has a simple process flow and is easy to prepare, which can meet the needs of mass production. Detailed Implementation

[0021] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0022] This invention provides an antibacterial masterbatch for melt-spun nylon 6, which is used to manufacture nylon 6 fiber products with antibacterial function. The amount added is 2% to 10% of the mass of melt-spun fiber-grade nylon 6 chips. The prepared antibacterial melt-spun nylon 6 fiber products have excellent properties such as antibacterial properties, water resistance, long-lasting antibacterial effect and safety.

[0023] The present invention relates to an antibacterial masterbatch for melt-spun nylon 6, comprising the following components in parts by weight: 100 portions of nylon 6 resin chips; 10-30 parts of long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material; 0.2~1.0 parts of the main antioxidant; 0.2-1.0 parts of auxiliary antioxidant; Lubricant 0.2~1.0 parts; Dispersant 0.2~1.0 parts.

[0024] The long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material is prepared by reacting the epoxy groups of the long-chain alkyl glycidyl ether with the guanidine salt polymer in a mass ratio of 1:2 to 2:1. The preparation reaction uses DMF as solvent, triethylamine to adjust the pH of the system to 8.0 to 9.5, and DMP-30 as catalyst to graft the epoxy groups of the long-chain alkyl glycidyl ether onto the secondary amine groups of the guanidine salt polymer backbone, and also onto the primary amine groups at the chain ends of the guanidine salt polymer. This introduces the hydrophobic long-chain alkyl group into the water-soluble guanidine salt polymer molecular chain, thus hydrophobically modifying the water-soluble guanidine salt polymer and preparing the long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material.

[0025] Example 1 1. Prepare powder #1 of long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material for later use: (1) Add 1000g of polyhexamethylene guanidine hydrochloride and 9000g of anhydrous dimethylformamide into an ultrasonic reactor (ultrasonic frequency 20kHz, power 100w~1000w adjustable), replace the reactor with argon gas for protection, and stir evenly to prepare a 10% polyhexamethylene guanidine hydrochloride solution. (2) Slowly add triethylamine to the ultrasonic reactor. When the pH of the polyhexamethylene guanidine hydrochloride solution in the reactor reaches 9.0, stop adding triethylamine. After stirring at room temperature for 2 hours, add 20g DMP-30 and 3g BHT to the reactor and continue stirring at room temperature for 1 hour until homogeneous. (3) Prepare a 30% CDO-TECHo-glycidyl glycidyl ether solution by mixing 1000g of CDO-TECHo-glycidyl ether with 3000g of anhydrous DMF, and preheat it to 50°C. Then slowly add it dropwise into the ultrasonic reactor mentioned above, while starting the ultrasonic generator and adjusting the power to 150w. (4) After the C12 to 14 tetradecyl glycidyl ether solution prepared in step (3) is added dropwise, the temperature is raised to 55°C under argon protection and the reaction is carried out by continuous stirring for 12 hours. (5) After the reaction is complete, stop the ultrasonic generator and heating, continue stirring, and after the temperature of the reaction vessel system is reduced to room temperature, slowly add glacial acetic acid to adjust the pH value of the system to neutral. (6) Slowly pour the reaction liquid in the reactor into 5 times the volume of cold methanol, stir vigorously to precipitate flocculent precipitate, and then filter it with a Buchner funnel to collect the precipitate. (7) Disperse the precipitate collected in step (6) in a mixture of acetone / ethanol (mass ratio 1:1), and ultrasonically wash for 10 minutes. Repeat three times until the washing solution is clear. (8) Place the precipitate washed in step (7) in a vacuum drying oven and dry it at 50°C for 12 hours to obtain light yellow long carbon chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material powder 1#, which is ready for further preparation of melt-spun nylon 6 antibacterial masterbatch.

[0026] 2. Preparation of antibacterial masterbatch (1) 2216g of nylon 6 resin chips that have been pre-dried at 100°C for 24 hours and other additives that have been pre-dried at 105°C for 3 hours, including 250.0g of long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material powder 1#, 7.0g of antioxidant 1010, 7.0g of antioxidant 168, 10.0g of ethylene bis-stearamide (EBS) and 10.0g of polyethylene wax, are thoroughly mixed in a mixer.

[0027] (2) The equipment for preparing antibacterial masterbatch is a parallel co-rotating meshing twin-screw extruder with a length-to-diameter ratio of 56. Multiple barrel sections are installed on the extruder body, and the hopper is installed on the extruder body and positioned close to the barrel. The barrel has thirteen sections, with the first section closest to the hopper. The extruder is equipped with a nitrogen protection system, including a nitrogen inlet pipe and a gas outlet pipe. Vacuum venting structures are located on the barrel sections at positions 5, 9, and 12. Nitrogen inlet components are located on the barrel sections at positions 2-4, 6-8, and 10-11. These components include a first valve, a pressure regulating component, and a flow regulating component. The hopper has a cover plate with a nitrogen inlet component and a nitrogen outlet component. A nitrogen air-cooling component is located at the die head of the extruder. The nitrogen inlet component is connected to the nitrogen inlet pipe, and the nitrogen outlet component is connected to the nitrogen outlet pipe. This achieves nitrogen protection of the material during the production process. The preparation device of this invention has a simple structure and reasonable design, which facilitates vacuum adjustment and inert gas protection during the preparation process, and has good application effect.

[0028] Add the mixture obtained in step (1) into the hopper of a twin-screw extruder protected by nitrogen, cover the hopper with the cover plate, open the stainless steel pipe valve for nitrogen inlet on the extruder head cover plate, set the barrel temperature of the parallel and co-rotating twin-screw extruder to 140℃~250℃ and the screw speed to 300rpm, open the stainless steel gas valves of the nitrogen inlet at the center of the top of the barrels from the 2nd to 4th, 6th to 8th and 10th to 11th sections from the feed inlet, and introduce nitrogen for protection, and start the vacuum system, opening vacuum exhaust chambers on the 5th, 9th and 12th sections from the feed inlet for vacuum degassing. After the blended material is melt-blended by the twin-screw extruder, it is granulated by the air-cooled die-cutting device. Nitrogen air cooling is used to protect the die head, and antibacterial masterbatch 1# for melt-spun nylon 6 is obtained.

[0029] 3. Preparation of melt-spun nylon 6 fiber samples Weigh 175g of the antibacterial masterbatch #1 for melt-spun nylon 6 obtained in step 2 and 4825g of fiber-grade nylon 6 resin chips. After thorough mixing in a mixer, the mixture is dried with hot air at 100℃ for 24 hours and then added to the hopper of a screw extruder. The material is metered and fed into the screw extruder, where it is fully melted and extruded. During the melting process, the temperatures of each zone of the screw and the chamber are 256, 258, 259, 260, 260, and 260℃, respectively. The melt is precisely metered by a metering pump and enters the spinning assembly, where it is extruded through a spinneret to form a filament bundle. The filament bundle is cooled by an outer ring blower and then precisely metered and oiled through an oil nozzle to form a bundle. After passing through a pre-networker, guide disc, and main networker, it is wound to form a test sample of antibacterial melt-spun nylon 6 fiber for testing its antibacterial properties.

[0030] The 17.5g of antibacterial masterbatch 1# and 482.5g of fiber-grade melt-spun nylon 6 resin chips prepared in this embodiment were thoroughly mixed in a mixer. Then, they were injection molded into 50mm*50mm*3mm samples at an injection temperature of 250℃ using an injection molding machine. After that, they were hot-pressed into thin sheets with a thickness of about 2mm at 250℃. Finally, they were cut into round pieces with a diameter of 5mm to form antibacterial nylon 6 resin test samples for antibacterial substance anti-leaching test.

[0031] Example 2 350g of antibacterial masterbatch 1# of melt-spun nylon 6 prepared in Example 1 and 4650g of fiber-grade melt-spun nylon 6 resin chips were thoroughly mixed in a mixer and then dried with hot air at 100°C for 24 hours. Antibacterial melt-spun nylon 6 fiber test samples were prepared using the same sample preparation method as in Example 1, and their antibacterial properties were tested.

[0032] 35g of the antibacterial masterbatch 1# for melt-spun nylon 6 and 465g of fiber-grade melt-spun nylon 6 resin chips prepared in Example 1 were thoroughly mixed in a mixer. Then, a 50mm*50mm*3mm sample was injection molded at 250℃ using an injection molding machine. The sample was then hot-pressed at 250℃ into a sheet with a thickness of about 2mm. Finally, the antibacterial nylon 6 resin chip test samples with a diameter of 5mm were cut into round pieces for antibacterial substance anti-leaching test.

[0033] Comparative Example 1 Antibacterial masterbatch was prepared by replacing 500.0g of long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material powder 1# in Example 1 with 500g of polyhexamethylene guanidine hydrochloride. The rest was the same as in Example 1. The antibacterial melt-spun nylon 6 test sample of Comparative Example 1 was obtained.

[0034] Comparative Example 2 Antibacterial masterbatch was prepared by replacing 500.0g of long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material powder 1# in Example 1 with 500g of polyhexamethylene guanidine hydrochloride. The rest was the same as in Example 2. The antibacterial melt-spun nylon 6 test sample of Comparative Example 2 was obtained.

[0035] The test standards for Examples 1-2 and Comparative Examples 1-2 are as follows: 1. Antibacterial Test Standard: The antibacterial melt-spun nylon 6 fiber test sample was placed in a polyester washing bag and washed 50 times according to the AAA grade test sample requirements of FZ / T73023-2006 "Antibacterial Knitted Fabrics". The antibacterial performance was then tested using the shaking method in Appendix D8. The tested bacteria were: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, and Candida albicans ATCC10231. After 50 washes, the test sample met the standard values ​​for 3A grade antibacterial knitted fabrics: the inhibition rates of Escherichia coli, Staphylococcus aureus, and Candida albicans were ≥70%, ≥80%, and ≥60%, respectively. 2. Antimicrobial substance leaching resistance test standard (inhibition ring width): The width of the inhibition ring of 5mm diameter antimicrobial melt-spun nylon 6 chips is tested according to GB 21551.1-2024 "Special Requirements for Antimicrobial Materials with Antimicrobial, Sterilizing, and Purifying Functions in Household and Similar Electrical Appliances". The inhibition ring width D≤5mm.

[0036] The test results are shown in the table below. As can be seen from the test results in the table, Examples 1 and 2 are melt-spun nylon 6 samples with the addition of the antibacterial masterbatch for melt-spun nylon 6 of the present invention. After washing 50 times with water according to the AAA grade test sample requirements of FZ / T 73023-2006 "Antibacterial Knitted Fabrics", the antibacterial rates against Escherichia coli, Staphylococcus aureus and Candida albicans all greatly exceeded the standard index requirements, demonstrating good antibacterial performance. Furthermore, the antibacterial resin used to prepare the corresponding antibacterial nylon 6 fiber samples was injection molded and then hot-pressed into antibacterial nylon 6 resin sheets, and the width of the inhibition ring was 0 mm. This further illustrates that the antibacterial agent of the melt-spun nylon 6 antibacterial masterbatch prepared according to the present invention has excellent anti-dissolution properties. In contrast, Comparative Examples 1 and 2, which contain highly water-soluble polyhexamethylene guanidine hydrochloride, showed a large loss of antibacterial active polyhexamethylene guanidine hydrochloride after washing 50 times, resulting in a very low antibacterial rate, which was far below the standard antibacterial index requirements, and thus did not have an effective antibacterial effect. Therefore, as can be seen from the test results in the table, the antibacterial masterbatch for melt-spun nylon 6 of the present invention has good antibacterial properties, with high antibacterial efficiency, resistance to water leaching, and washability. It is also safe and silver-free, and can be used to prepare melt-spun nylon 6 fiber products with antibacterial functions. The addition amount is 2-10% of the fiber-grade melt-spun nylon 6 chip resin matrix. The antibacterial grade of the prepared antibacterial melt-spun nylon 6 fiber products even reaches the AAA level requirement, which can better meet the application needs. It also has the advantages of safety, broad spectrum, resistance to water leaching, and long-lasting antibacterial effect, and has broad market prospects and commercial value.

[0037] The above embodiments are for illustrative purposes only and are not intended to limit the invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the invention. Therefore, all equivalent technical solutions should also fall within the scope of the invention and should be defined by the claims.

Claims

1. An antibacterial masterbatch for melt-spun nylon 6, characterized in that, Includes the following components in parts by mass, 100 portions of nylon 6 resin chips; 10-30 parts of long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material; 0.2~1.0 parts of the main antioxidant; 0.2-1.0 parts of auxiliary antioxidant; Lubricant 0.2~1.0 parts; Dispersant 0.2~1.0 parts.

2. The antibacterial masterbatch for melt-spun nylon 6 according to claim 1, characterized in that, The long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material comprises the following components in the following ratio: the mass ratio of long-chain glycidyl ether to guanidine salt polymer is 1:0.5-2.

3. The antibacterial masterbatch for melt-spun nylon 6 according to claim 2, characterized in that, The long-chain alkyl glycidyl ether is selected from at least one of C12-14-alkyl glycidyl ether, C16-alkyl glycidyl ether, and C18-alkyl glycidyl ether. The guanidine salt polymer is selected from at least one of polyhexamethylene guanidine hydrochloride, polyhexamethylene biguanidine hydrochloride, polyhexamethylene guanidine propionate, polyhexamethylene biguanidine propionate, polyhexamethylene guanidine nitrate, polyhexamethylene biguanidine nitrate, polyhexamethylene guanidine phosphate, polyhexamethylene biguanidine phosphate, polyhexamethylene guanidine carbonate, and polyhexamethylene biguanidine carbonate.

4. The antibacterial masterbatch for melt-spun nylon 6 according to claim 2, characterized in that, The preparation method of the long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material includes the following steps: Step (1): Under the protection of an inert gas, the guanidine salt polymer and anhydrous dimethylformamide are added to the ultrasonic reactor and mixed to prepare a guanidine salt polymer solution with a mass concentration of 5%~10%. Triethylamine is slowly added dropwise to the ultrasonic reactor to adjust the pH value of the guanidine salt polymer solution to 8.0~9.

5. After stirring at room temperature for 1~2 hours, 2,4,6-tris(dimethylaminomethyl)phenol and butylhydroxytoluene are added to the reaction system. Step (2): Mix long-chain alkyl glycidyl ether with anhydrous dimethylformamide to prepare a long-chain alkyl glycidyl ether solution with a mass concentration of 20%~40%, and preheat it to 50~60℃. Then slowly add it dropwise into the ultrasonic reactor of step (1). During the dropwise addition, the ultrasonic generator of the ultrasonic reactor is started at the same time. After the dropwise addition is completed, under the protection of inert gas, the temperature is raised to 50℃~60℃ and the reaction is continuously stirred for 4~16 hours. Step (3): After the reaction in step (2) is completed, the reaction system is cooled to room temperature, a small amount of glacial acetic acid is added to adjust the pH value to neutral, the reaction solution is slowly poured into 5 times the volume of cold methanol, and the product is stirred vigorously to precipitate as a white flocculent precipitate. The product is then filtered using a Buchner funnel and the precipitate is collected. The precipitate is dispersed in a 1:1 mass ratio acetone / ethanol mixture and ultrasonically washed for 10 minutes. This is repeated 3 times until the washing solution is transparent. The washed precipitate is placed in a vacuum drying oven and dried at 50°C for 12 hours to obtain a white to light yellow long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material solid powder product.

5. The antibacterial masterbatch for melt-spun nylon 6 according to claim 4, characterized in that, The amount of 2,4,6-tris(dimethylaminomethyl)phenol used is 0.1% to 3% of the mass of the long-chain alkyl glycidyl ether; the amount of butyl hydroxytoluene used is 0.1% to 0.3% of the mass of the long-chain alkyl glycidyl ether.

6. The antibacterial masterbatch for melt-spun nylon 6 according to claim 1, characterized in that, The primary antioxidant is selected from at least one of antioxidant 1098 and antioxidant 1330, the secondary antioxidant is selected from at least one of antioxidant 168 and antioxidant 626, the lubricant is selected from ethylene bis-stearamide, and the dispersant is selected from polyethylene wax.

7. The method for preparing antibacterial masterbatch according to any one of claims 1-6, characterized in that, A parallel, co-rotating, meshing twin-screw extruder is used, which provides nitrogen protection for the material during production. This extruder consists of thirteen barrel sections. The preparation method includes the following steps: Nylon 6 resin chips were pre-dried at 100°C with hot air for 24 hours. The dried nylon 6 resin chips were then mixed evenly with the long-chain alkyl glycidyl ether modified guanidine salt polymer antimicrobial material, primary antioxidant, secondary antioxidant, lubricant, and dispersant in a certain proportion. This mixture was then added to the hopper of a twin-screw extruder. The hopper was protected with nitrogen gas. The temperature of each barrel of the twin-screw extruder was set to 180~250°C, and the screw speed was 200~350 rpm. Nitrogen gas is introduced into the 2nd to 4th, 6th to 8th, and 10th to 11th sections of the cylinder near the feed inlet for protection. Vacuum degassing is performed by opening vacuum exhaust chambers on the 5th, 9th, and 12th sections of the cylinder near the feed inlet. The blended material is melt-blended by the twin-screw extruder and then granulated by an air-cooled die pelletizing device. Nitrogen air cooling is used to protect the die head, thus producing the antibacterial masterbatch for melt-spun nylon 6.

8. A melt-spun nylon 6, characterized in that, The amount of antibacterial masterbatch prepared by the preparation method described in claim 7 is 2-10% of the mass of nylon 6 resin chip matrix.

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