Antibacterial halogen-free flame-retardant reinforced cross-linked polyethylene composite fiber and preparation method thereof

Abstract

The invention relates to the field of polyethylene composite fibers, and discloses an antibacterial halogen-free flame-retardant reinforced cross-linked polyethylene composite fiber and a preparation method thereof.The composite fiber is prepared from linear low-density polyethylene resin, modified magnesium hydroxide, a silver-loaded zirconium phosphate inorganic antibacterial agent, tetra [beta-(3, 4, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, the composite material is prepared from the following components: 1, 3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester antioxidant, dicumyl peroxide cross-linking agent, hydrogenated castor oil dispersing agent and industrial white oil solvent. The modified magnesium hydroxide is prepared from magnesium hydroxide, deionized water, stearic acid and a sodium hydroxide solution. The composite fiber disclosed by the invention has relatively good mechanical property, antibacterial property and flame retardance.

Description

Technical Field

[0001] This invention relates to the field of polyethylene composite fibers, specifically to an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber and its preparation method. Background Technology

[0002] Polyethylene fiber (ethylene filament) is a fibrous material obtained by melt spinning polyethylene. It includes short fibers and filaments. The mechanical strength of this fiber can be adjusted by the spinning process parameters. Moreover, the wet strength and elongation are the same as those in the dry state. Polyethylene fiber has the advantages of high strength, low density and good insulation. It is mainly used to produce various industrial textiles, especially filter materials, tarpaulins and mesh belts.

[0003] Patent CN119980499B discloses a method for preparing cool-feeling polyethylene fiber, including the following steps: Step 1, preparing a modifier: S1, weigh magnesium silicide nanopowder and disperse it in an ethanol solution, then add an epoxy silane coupling agent, reflux in a water bath, then centrifuge, wash and dry to obtain product A; S2, weigh 5-amino-2-mercaptobenzimidazole and dissolve it in tetrahydrofuran, add it to product A, reflux in a water bath again, centrifuge, wash and dry after the reaction is complete to obtain product B; S3, weigh 4-vinylguaiacol and add N,N-dimethylformyl In the first step, after stirring the amine until homogeneous, product B is added and stirred until homogeneous again. A photoinitiator is then added, and the reaction is carried out under ultraviolet light. After the reaction is complete, the product is washed and dried to obtain the modifier. The second step involves preparing the modified resin: antioxidants and nucleating agents are added to an organic solvent and stirred thoroughly. High-density polyethylene resin is then added, and the mixture is heated and stirred until dissolved. The modifier is then added, and the mixture is stirred thoroughly again. The solvent is removed under reduced pressure, and the resin is dried to obtain the modified polyethylene resin. The third step involves melt spinning: the modified polyethylene resin is melted in a twin-screw extruder and then extruded through a spinning machine to obtain cool-feeling polyethylene fiber. However, this method has some drawbacks: the fiber lacks antibacterial properties during use, making it prone to microbial growth, and its flame retardancy is poor. Summary of the Invention

[0004] The purpose of this invention is to provide an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber, wherein the composite fiber is prepared from linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] antioxidant, dicumyl peroxide cross-linking agent, hydrogenated castor oil dispersant, and industrial white oil solvent; the modified magnesium hydroxide is prepared from magnesium hydroxide, deionized water, stearic acid, and sodium hydroxide solution.

[0006] Furthermore, the melt index of linear low-density polyethylene resin is 20-30 g / 10 min (190℃ / 2.16 kg).

[0007] Furthermore, the particle size of magnesium hydroxide is 0.8-1.2 μm.

[0008] Furthermore, the particle size of the silver-loaded zirconium phosphate inorganic antibacterial agent is 0.1-0.3 μm, and the silver content is 4.0-4.2%.

[0009] Furthermore, a method for preparing antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber includes the following steps: (1) Add magnesium hydroxide to deionized water and stir at 800-1000 rpm for 20-30 minutes. Then, treat it with ultrasound at 200-400W for 10-15 minutes to obtain a suspension with a solid content of 15-20%. Mix stearic acid and sodium hydroxide solution with a mass fraction of 5-10% at a mass ratio of 1:(3-5). Stir at 200-300 rpm for 15-20 minutes at 70-75℃ to obtain sodium stearate solution. Slowly add sodium stearate solution to magnesium hydroxide suspension over 30-40 minutes at 75-85℃, while stirring continuously at 400-500 rpm. After the addition is complete, continue stirring at 80-85℃ for 2-3 hours. After filtration, wash with deionized water 3-5 times and dry in a vacuum drying oven at 100-105℃ for 4-6 hours to obtain modified magnesium hydroxide. (2) Linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] antioxidant are placed in a mixer and mixed at 80-85℃ and 300-400 rpm for 15-20 minutes; then melt extrusion granulation is carried out using a twin-screw extruder to obtain flame-retardant antibacterial masterbatch; (3) After drying the linear low-density polyethylene resin and the flame-retardant and antibacterial masterbatch obtained in step (2) at 60-65℃ for 1-2 hours, mix them in a mixer at 200-300 rpm for 10-15 minutes at room temperature, and then melt spin them to obtain nascent fibers. The melt spinning conditions are: spinneret orifice diameter 0.3-0.4 mm, spinning rate 800-1000 m / min, and spinning temperature 190-200℃. (4) Add dicumyl peroxide crosslinking agent and hydrogenated castor oil dispersant to industrial white oil solvent with a distillation range of 190-220℃, and stir at 300-400 rpm for 60-70 minutes at 70-75℃ to obtain impregnation solution. (5) Immerse the nascent fibers obtained in step (3) in an impregnation solution at 50-60°C for 4-5 hours; (6) The impregnated fibers are subjected to graded heat treatment by a heat setting machine. The temperature of the first zone is 110-115℃ and the treatment time is 90-100 seconds. The temperature of the second zone is 175-180℃ and the treatment time is 120-130 seconds. The temperature of the third zone is 150-155℃ and the treatment time is 60-70 seconds to obtain composite fibers.

[0010] Furthermore, in step (1), the mass ratio of sodium stearate solution to magnesium hydroxide suspension is 1:(8-12).

[0011] Furthermore, in step (2), the mass ratio of linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] antioxidant is 60:(33-37):(4-6):(0.4-0.6).

[0012] Furthermore, in step (2), the temperature of the twin-screw extruder is set as follows: Zone 1 150-155℃, Zone 2 170-175℃, Zone 3 180-185℃, and the die head 185-190℃. The screw speed is 250-300 rpm, and the length-to-diameter ratio is 39-41:1.

[0013] Furthermore, in step (3), the mass ratio of linear low-density polyethylene resin to flame-retardant antibacterial masterbatch is (30-40):(20-30).

[0014] Furthermore, in step (4), the mass ratio of dicumyl peroxide crosslinking agent, hydrogenated castor oil dispersant, and industrial white oil solvent is (4-6):(0.5-1.0):(93-95).

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. Stearic acid reacts with sodium hydroxide to form sodium stearate, which forms an organic coating layer on the surface of magnesium hydroxide, improving its dispersibility and compatibility in the polyethylene matrix. Silver-loaded zirconium phosphate inorganic antibacterial agent is used to slowly release silver ions through ion exchange, achieving antibacterial properties. Pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] antioxidant is used to terminate the free radical oxidation reaction of the polyethylene molecular chain by providing hydrogen atoms, preventing thermal oxidative degradation during processing. Dicumyl peroxide crosslinking agent generates free radicals under heating conditions. These free radicals abstract hydrogen atoms from the polyethylene molecular chain to form macromolecular free radicals, which then form a three-dimensional network crosslinked structure through carbon-carbon bonds. Hydrogenated castor oil dispersant is used, whose amphiphilic molecular structure reduces the solid-liquid interfacial energy, resulting in more uniform dispersion of the dicumyl peroxide crosslinking agent in industrial white oil solvents. Heat treatment promotes the crosslinking reaction, thus giving the composite fiber better mechanical properties, antibacterial properties, and flame retardancy. Detailed Implementation

[0016] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0017] An antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber is provided, wherein the composite fiber is prepared from linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] antioxidant, dicumyl peroxide cross-linking agent, hydrogenated castor oil dispersant, and industrial white oil solvent; the modified magnesium hydroxide is prepared from magnesium hydroxide, deionized water, stearic acid, and sodium hydroxide solution.

[0018] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products. Example

[0019] (1) Add magnesium hydroxide with a particle size of 0.8 μm to deionized water and stir at 800 rpm for 20 minutes. Then, treat it with ultrasound at 200 W for 10 minutes to obtain a suspension with a solid content of 15%. Mix stearic acid and sodium hydroxide solution with a mass fraction of 5% at a mass ratio of 1:3 and stir at 200 rpm for 15 minutes at 70°C to obtain sodium stearate solution. At 75°C, slowly add sodium stearate solution to magnesium hydroxide suspension over 30 minutes while stirring continuously at 400 rpm. After the addition is complete, continue stirring at 80°C for 2 hours. After filtration, wash with deionized water 3 times and dry in a vacuum drying oven at 100°C for 4 hours, modified magnesium hydroxide is obtained. The mass ratio of sodium stearate solution to magnesium hydroxide suspension is 1:8.

[0020] (2) Linear low-density polyethylene resin with a melt index of 20 g / 10 min (190℃ / 2.16 kg), modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent with a particle size of 0.1 μm and a silver content of 4.0%, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] antioxidant were placed in a mixer and mixed at 80℃ and 300 rpm for 15 minutes. Subsequently, a twin-screw extruder was used for melt extrusion granulation to obtain flame-retardant and antibacterial masterbatch. The twin-screw extruder temperature was set as follows: Zone 1 150℃, Zone 2 170℃, Zone 3 180℃, and Die Head 185℃; the screw speed was 250 rpm; and the length-to-diameter ratio was 39:1. The mass ratio of linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] antioxidant is 60:33:4:0.4.

[0021] (3) Linear low-density polyethylene resin with a melt index of 20 g / 10 min (190℃ / 2.16 kg) and the flame-retardant and antibacterial masterbatch obtained in step (2) were dried at 60℃ for 1 hour, and then mixed at 200 rpm for 10 minutes at room temperature in a mixer. Then, melt spinning was performed to obtain nascent fibers. The melt spinning conditions were: spinneret orifice diameter 0.3 mm, spinning rate 800 m / min, and spinning temperature 190℃.

[0022] The mass ratio of linear low-density polyethylene resin to flame-retardant antibacterial masterbatch is 30:20.

[0023] (4) Add dicumyl peroxide crosslinking agent and hydrogenated castor oil dispersant to industrial white oil solvent with a distillation range of 190°C, and stir at 300 rpm for 60 minutes at 70°C to obtain impregnation solution. The mass ratio of dicumyl peroxide crosslinking agent, hydrogenated castor oil dispersant, and industrial white oil solvent is 4:0.5:93.

[0024] (5) Immerse the nascent fibers obtained in step (3) in an impregnation solution at 50°C for 4 hours; (6) The impregnated fibers are subjected to graded heat treatment by a heat setting machine. The temperature of the first zone is 110℃ and the treatment time is 90 seconds. The temperature of the second zone is 175℃ and the treatment time is 120 seconds. The temperature of the third zone is 150℃ and the treatment time is 60 seconds to obtain composite fibers. Example

[0025] (1) Add magnesium hydroxide with a particle size of 1.0 μm to deionized water and stir at 900 rpm for 25 minutes. Then, sonicate it at 300 W for 12.5 minutes to obtain a suspension with a solid content of 17.5%. Mix stearic acid and sodium hydroxide solution with a mass fraction of 7.5% at a mass ratio of 1:4 and stir at 250 rpm for 17.5 minutes at 72.5℃ to obtain sodium stearate solution. At 80℃, slowly add sodium stearate solution to magnesium hydroxide suspension over 35 minutes while stirring continuously at 450 rpm. After the addition is complete, continue stirring at 82.5℃ for 2.5 hours. After filtration, washing with deionized water 4 times, and drying in a vacuum drying oven at 102.5℃ for 5 hours, modified magnesium hydroxide is obtained. The mass ratio of sodium stearate solution to magnesium hydroxide suspension is 1:10.

[0026] (2) Linear low-density polyethylene resin with a melt index of 25 g / 10 min (190℃ / 2.16 kg), modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent with a particle size of 0.2 μm and a silver content of 4.1%, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] antioxidant were placed in a mixer and mixed at 82.5℃ and 350 rpm for 17.5 minutes. Subsequently, a twin-screw extruder was used for melt extrusion granulation to obtain flame-retardant and antibacterial masterbatch. The twin-screw extruder temperature was set as follows: Zone 1 152.5℃, Zone 2 172.5℃, Zone 3 182.5℃, and Die Head 187.5℃. The screw speed was 275 rpm, and the length-to-diameter ratio was 40:1. The mass ratio of linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] antioxidant is 60:35:5:0.5.

[0027] (3) Linear low-density polyethylene resin with a melt index of 25 g / 10 min (190℃ / 2.16 kg) and the flame-retardant and antibacterial masterbatch obtained in step (2) were dried at 62.5℃ for 1.5 hours, and then mixed at room temperature in a mixer at a speed of 250 rpm for 12.5 minutes. Then, melt spinning was performed to obtain nascent fibers. The melt spinning conditions were: spinneret orifice diameter 0.35 mm, spinning rate 900 m / min, and spinning temperature 195℃.

[0028] The mass ratio of linear low-density polyethylene resin to flame-retardant antibacterial masterbatch is 35:25.

[0029] (4) Add dicumyl peroxide crosslinking agent and hydrogenated castor oil dispersant to industrial white oil solvent with a distillation range of 200℃, and stir at 350 rpm for 65 minutes at 72.5℃ to obtain impregnation solution. The mass ratio of dicumyl peroxide crosslinking agent, hydrogenated castor oil dispersant, and industrial white oil solvent is 5:0.75:94.

[0030] (5) Immerse the nascent fibers obtained in step (3) in an impregnation solution at 55°C for 4.5 hours; (6) The impregnated fibers are subjected to graded heat treatment by a heat setting machine. The temperature of the first zone is 112.5℃ and the treatment time is 95 seconds. The temperature of the second zone is 177.5℃ and the treatment time is 125 seconds. The temperature of the third zone is 152.5℃ and the treatment time is 65 seconds to obtain composite fibers. Example

[0031] (1) Add magnesium hydroxide with a particle size of 1.2 μm to deionized water and stir at 1000 rpm for 30 minutes. Then, treat it with ultrasound at 400 W for 15 minutes to obtain a suspension with a solid content of 20%. Mix stearic acid and sodium hydroxide solution with a mass fraction of 10% at a mass ratio of 1:5 and stir at 300 rpm for 20 minutes at 75°C to obtain sodium stearate solution. At 85°C, slowly add sodium stearate solution to magnesium hydroxide suspension over 40 minutes while stirring continuously at 500 rpm. After the addition is complete, continue stirring at 85°C for 3 hours. After filtration, wash with deionized water 5 times and dry in a vacuum drying oven at 105°C for 6 hours, modified magnesium hydroxide is obtained. The mass ratio of sodium stearate solution to magnesium hydroxide suspension is 1:12.

[0032] (2) Linear low-density polyethylene resin with a melt index of 30 g / 10 min (190℃ / 2.16 kg), modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent with a particle size of 0.3 μm and a silver content of 4.2%, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] antioxidant were placed in a mixer and mixed at 85℃ and 400 rpm for 20 minutes. Subsequently, a twin-screw extruder was used for melt extrusion granulation to obtain flame-retardant and antibacterial masterbatch. The twin-screw extruder temperature was set as follows: zone 1 155℃, zone 2 175℃, zone 3 185℃, die head 190℃, screw speed 300 rpm, and length-to-diameter ratio 41:1. The mass ratio of linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] antioxidant is 60:37:6:0.6.

[0033] (3) Linear low-density polyethylene resin with a melt index of 30 g / 10 min (190℃ / 2.16 kg) and the flame-retardant and antibacterial masterbatch obtained in step (2) were dried at 65℃ for 2 hours, and then mixed at 300 rpm for 15 minutes at room temperature in a mixer. Then, melt spinning was performed to obtain nascent fibers. The melt spinning conditions were: spinneret orifice diameter 0.4 mm, spinning rate 1000 m / min, and spinning temperature 200℃.

[0034] The mass ratio of linear low-density polyethylene resin to flame-retardant antibacterial masterbatch is 40:30.

[0035] (4) Add dicumyl peroxide crosslinking agent and hydrogenated castor oil dispersant to industrial white oil solvent with a distillation range of 220°C, and stir at 400 rpm for 70 minutes at 75°C to obtain impregnation solution. The mass ratio of dicumyl peroxide crosslinking agent, hydrogenated castor oil dispersant, and industrial white oil solvent is 6:1.0:95.

[0036] (5) Immerse the nascent fibers obtained in step (3) in an impregnation solution at 60°C for 5 hours; (6) The impregnated fibers are subjected to graded heat treatment by a heat setting machine. The temperature of the first zone is 115℃ and the treatment time is 100 seconds. The temperature of the second zone is 180℃ and the treatment time is 130 seconds. The temperature of the third zone is 155℃ and the treatment time is 70 seconds to obtain composite fibers.

[0037] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that no surface modification of magnesium hydroxide is performed.

[0038] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that no silver-loaded zirconium phosphate inorganic antibacterial agent was added.

[0039] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that dicumyl peroxide crosslinking agent is not added.

[0040] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that no impregnation treatment or subsequent heat treatment process is performed, and the nascent fiber is directly used as the finished fiber.

[0041] Tensile strength and elongation at break were tested according to GB / T14344-2022. The fibers were woven in a plain weave with a fabric density of 120 warp threads / 10cm and 80 weft threads / 10cm. The antibacterial properties against Staphylococcus aureus and Escherichia coli were tested according to GB / T20944.3-2008, and the flame retardant properties were tested according to GB / T5454-1997.

[0042] Table 1 below shows the performance analysis results of the embodiments and comparative examples of the present invention.

[0043] sample Fracture strength (cN / dtex) Elongation at break (%) Limiting oxygen index (%) Staphylococcus aureus antibacterial rate (%) Escherichia coli antibacterial rate (%) Example 1 5.0 28 26 99.6 99.4 Example 2 5.3 32 27 99.7 99.6 Example 3 4.8 29 26 99.5 99.3 Comparative Example 1 3.3 50 25 99.1 98.9 Comparative Example 2 3.8 140 26 No antibacterial properties No antibacterial properties Comparative Example 3 3.5 200 24 99.1 98.9 Comparative Example 4 3.8 140 25 98.7 98.4 Experimental data from the examples and comparative examples show that the present invention uses the reaction of stearic acid and sodium hydroxide to generate sodium stearate, forming an organic coating layer on the surface of magnesium hydroxide, which improves its dispersibility and compatibility in the polyethylene matrix; it uses silver-loaded zirconium phosphate inorganic antibacterial agent to slowly release silver ions through ion exchange; it uses dicumyl peroxide crosslinking agent to generate free radicals under heating conditions, and these free radicals abstract hydrogen atoms from the polyethylene molecular chain to form macromolecular free radicals, which are then bonded by carbon-carbon bonds to form a three-dimensional network crosslinked structure; it uses hydrogenated castor oil dispersant to reduce the solid-liquid interface energy through its amphiphilic molecular structure, ensuring the uniform dispersion of the dicumyl peroxide crosslinking agent in industrial white oil solvent; and it promotes the crosslinking reaction through heat treatment, thereby giving the composite fiber better mechanical properties, antibacterial properties, and flame retardancy.

[0044] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. An antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber, characterized in that, The composite fiber is made from linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] antioxidant, dicumyl peroxide crosslinking agent, hydrogenated castor oil dispersant, and industrial white oil solvent; the modified magnesium hydroxide is made from magnesium hydroxide, deionized water, stearic acid, and sodium hydroxide solution.

2. The antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 1, characterized in that... The melt index of linear low-density polyethylene resin is 20-30 g / 10 min (190℃ / 2.16 kg).

3. The antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 2, characterized in that... The particle size of magnesium hydroxide is 0.8-1.2 μm.

4. The antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 3, characterized in that... The particle size of the silver-loaded zirconium phosphate inorganic antibacterial agent is 0.1-0.3μm, and the silver content is 4.0-4.2%.

5. The method for preparing an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 4, characterized in that, Includes the following steps: (1) Add magnesium hydroxide to deionized water and stir at 800-1000 rpm for 20-30 minutes. Then, treat it with ultrasound at 200-400W for 10-15 minutes to obtain a suspension with a solid content of 15-20%. Mix stearic acid and sodium hydroxide solution with a mass fraction of 5-10% at a mass ratio of 1:(3-5). Stir at 200-300 rpm for 15-20 minutes at 70-75℃ to obtain sodium stearate solution. Slowly add sodium stearate solution to magnesium hydroxide suspension over 30-40 minutes at 75-85℃, while stirring continuously at 400-500 rpm. After the addition is complete, continue stirring at 80-85℃ for 2-3 hours. After filtration, wash with deionized water 3-5 times and dry in a vacuum drying oven at 100-105℃ for 4-6 hours to obtain modified magnesium hydroxide. (2) Linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] antioxidant are placed in a mixer and mixed at 80-85℃ and 300-400 rpm for 15-20 minutes; then melt extrusion granulation is carried out using a twin-screw extruder to obtain flame-retardant antibacterial masterbatch; (3) After drying the linear low-density polyethylene resin and the flame-retardant and antibacterial masterbatch obtained in step (2) at 60-65℃ for 1-2 hours, mix them in a mixer at 200-300 rpm for 10-15 minutes at room temperature, and then melt spin them to obtain nascent fibers. The melt spinning conditions are: spinneret orifice diameter 0.3-0.4 mm, spinning rate 800-1000 m / min, and spinning temperature 190-200℃. (4) Add dicumyl peroxide crosslinking agent and hydrogenated castor oil dispersant to industrial white oil solvent with a distillation range of 190-220℃, and stir at 300-400 rpm for 60-70 minutes at 70-75℃ to obtain impregnation solution. (5) Immerse the nascent fibers obtained in step (3) in an impregnation solution at 50-60°C for 4-5 hours; (6) The impregnated fibers are subjected to graded heat treatment by a heat setting machine. The temperature of the first zone is 110-115℃ and the treatment time is 90-100 seconds. The temperature of the second zone is 175-180℃ and the treatment time is 120-130 seconds. The temperature of the third zone is 150-155℃ and the treatment time is 60-70 seconds to obtain composite fibers.

6. The method for preparing an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 5, characterized in that... In step (1), the mass ratio of sodium stearate solution to magnesium hydroxide suspension is 1:(8-12).

7. The method for preparing an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 5, characterized in that... In step (2), the mass ratio of linear low-density polyethylene resin, modified magnesium hydroxide, silver-loaded zirconium phosphate inorganic antibacterial agent, and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] antioxidant is 60:(33-37):(4-6):(0.4-0.6).

8. The method for preparing an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 5, characterized in that... In step (2), the temperature of the twin-screw extruder is set as follows: Zone 1 150-155℃, Zone 2 170-175℃, Zone 3 180-185℃, and Die head 185-190℃. The screw speed is 250-300rpm and the length-to-diameter ratio is 39-41:

1.

9. The method for preparing an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 5, characterized in that... In step (3), the mass ratio of linear low-density polyethylene resin to flame-retardant antibacterial masterbatch is (30-40):(20-30).

10. The method for preparing an antibacterial, halogen-free, flame-retardant, reinforced cross-linked polyethylene composite fiber according to claim 5, characterized in that... In step (4), the mass ratio of dicumyl peroxide crosslinking agent, hydrogenated castor oil dispersant, and industrial white oil solvent is (4-6):(0.5-1.0):(93-95).