High-toughness anti-ultraviolet PET (Polyethylene Terephthalate) fiber and preparation method thereof

Abstract

The invention discloses a high-toughness anti-ultraviolet PET (Polyethylene Terephthalate) fiber and a preparation method thereof, belongs to the technical field of polyester fibers, and is used for solving the technical problem that the mechanical strength, the ultraviolet resistance and the moisture absorption and quick drying performance of the PET fiber in the prior art need to be further improved. The invention relates to a high-toughness anti-ultraviolet PET (Polyethylene Terephthalate) fiber which is prepared from modified PET, modified polyester, modified montmorillonite, epoxy modified polysiloxane and an additive in a weight ratio of (55-60): (30-35): (10-16): (20-30): (3-5), according to the invention, the modified montmorillonite is used as a heterogeneous nucleation point, and a PET molecular chain composed of the modified PET, the modified polyester and the epoxy modified polysiloxane is induced to be arranged in a height orientation manner along the drafting direction, so that the breaking strength of the PET fiber is improved, a relatively high elongation at break is maintained, and the anti-ultraviolet effect and the moisture-absorbing and quick-drying performance of the PET fiber are improved.

Description

Technical Field

[0001] This invention relates to the field of polyester fiber processing technology, specifically to a high-toughness UV-resistant PET fiber and its preparation method. Background Technology

[0002] Polyethylene terephthalate (PET) fiber, commonly known as polyester resin, has become one of the world's largest-produced and most widely used synthetic fibers due to its excellent mechanical properties, wrinkle resistance, drape, wash-and-wear properties, and relatively low cost.

[0003] However, the rigid structure of the PET molecular chain in the existing technology makes the fiber brittle and prone to breakage under high stretching or complex stress environment. The ester group and benzene ring structure in the PET fiber molecular chain are easily damaged by ultraviolet light, which can cause photo-oxidative degradation, resulting in yellowing of the fiber, reduced strength, and serious impact on the weather resistance of outdoor products.

[0004] For example, the invention patent with publication number CN108456947A involves an anti-ultraviolet PET fiber and its preparation method. The method involves uniformly mixing PET chips with hollow porous microspheres of composite organic ultraviolet absorbers and then melt spinning to obtain anti-ultraviolet PET fiber. The final product contains hollow porous microspheres of composite organic ultraviolet absorbers that are uniformly dispersed. The hollow porous microspheres of composite organic ultraviolet absorbers are mainly composed of cross-linked spheres and organic ultraviolet absorbers. The cross-linked spheres are hollow inside, porous on the surface, and have a cross-linked structure formed by the cross-linking of molecular chains of styrene-difunctional dimethacrylate monomer copolymers. The organic ultraviolet absorber is doped in the cross-linked structure and / or attached to the inner wall of the cross-linked spheres. The final product has a breaking strength reduction rate of less than 20.5% after irradiation under 365nm ultraviolet light for 240 hours.

[0005] However, when the above methods are used to modify fibers for UV resistance, inorganic particles are difficult to disperse uniformly in the melt-mixed system, resulting in the need to further improve the UV resistance and mechanical strength of the material. In addition, the hydrophobicity of PET results in low moisture absorption, making it difficult for sweat to diffuse and evaporate quickly, which can easily cause discomfort when wearing the garment and make it difficult to meet the needs of functional textiles such as sportswear and hygiene materials. Summary of the Invention

[0006] The purpose of this invention is to provide a high-toughness UV-resistant PET fiber and its preparation method, in order to solve the technical problem that the mechanical strength, UV resistance and moisture absorption and quick-drying properties of PET fibers in the prior art need to be further improved.

[0007] The objective of this invention can be achieved through the following technical solution: a high-toughness UV-resistant PET fiber, wherein the high-toughness UV-resistant PET fiber is composed of modified PET, modified polyester, modified montmorillonite, epoxy-modified polysiloxane and additives in a weight ratio of 55-60:30-35:10-16:20-30:3-5; The modified polyester is prepared as follows: sebacic acid, diethylene glycol, 3-amino-1,5-pentanediol and catalyst are mixed, the reaction system temperature is raised to 128-135℃, and the reaction is maintained until the acid value is 120mgKOH / g. The reaction is continued for 60-80min, and then post-treatment is performed to obtain linear polyester; under an inert gas atmosphere, linear polyester and N,N-dimethylformamide are mixed and stirred at room temperature until the system is dissolved. The reaction system temperature is lowered to 0-5℃, catalyst is added to the reaction system, and then 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride is added to the reaction system. The reaction is maintained for 2-3h, and then post-treatment is performed to obtain modified polyester.

[0008] The synthesis reaction mechanism of modified polyester is as follows: In the formula: ; During the preparation process, the carboxyl group on the sebacic acid molecule undergoes an esterification reaction with the hydroxyl group on the diethylene glycol or 3-amino-1,5-pentanediol molecule to form a long straight-chain polycarbonate structure. Then, under low temperature conditions, the acyl chloride on the 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride molecule undergoes nucleophilic substitution with the amino group on the linear polyester molecule, forming hindered phenolic modification on the linear polyester molecular chain, thus preparing the modified polyester.

[0009] Furthermore, the ratio of sebacic acid, diethylene glycol, and 3-amino-1,5-pentanediol is 2.2 mol:1 mol:1 mol, the weight ratio of the catalyst to sebacic acid is 1:10, the catalyst is p-toluenesulfonic acid, and the post-treatment includes: after the reaction is complete, the reactants are poured out while hot, cooled and solidified, and pulverized to obtain linear polyester; the ratio of linear polyester, N,N-dimethylformamide, catalyst, and 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride is 7-8 g:80 mL:0.5-0.7 g:0.7-0.8 g, and the post-treatment includes: after the reaction is complete, the temperature of the reaction system is raised to room temperature, purified water is added to the reaction system, the mixture is stirred and dispersed for 30-50 min, filtered, the filter cake is washed three times with purified water and then dried, the filter cake is transferred to a drying oven at 60-70℃ and dried to constant weight to obtain modified polyester.

[0010] Furthermore, the modified PET is prepared by adding PET, allyl polyethylene glycol and an initiator into a torque rheometer and melting and mixing for 8-10 minutes to obtain modified PET.

[0011] The synthesis reaction mechanism of modified PET is as follows: During the reaction, under the action of the initiator, the olefin double bond on the allyl polyethylene glycol molecule undergoes a free radical addition reaction with the methylene carbon on the PET molecular chain to form polyethylene glycol chain modification, thus preparing modified PET.

[0012] Furthermore, the weight ratio of PET, allyl polyethylene glycol, and initiator is 20:1:0.1, the initiator is dicumyl peroxide, and the temperature of the torque rheometer is 245-255℃, and the rotation speed is 50-60 r / min.

[0013] Furthermore, modified montmorillonite is obtained through the following steps: A1. Tetrabutyl titanate and anhydrous ethanol are mixed and stirred. Acetic acid solution is added to the reaction system and stirred and dispersed at room temperature for 20-30 min. Sodium montmorillonite is added to the reaction system and stirred and dispersed for 60-80 min. After post-treatment, titanium-modified montmorillonite is obtained. A2. Mix titanium-modified montmorillonite, sodium hexametaphosphate, hexamethyl melamine, and deionized water, and stir and disperse at room temperature for 60-80 min. Add hydrochloric acid to the reaction system to adjust the pH of the system to 5-5.5. Raise the temperature of the reaction system to 70-80℃ and keep the reaction at this temperature for 5-6 h. After post-treatment, the coated modified montmorillonite is obtained. A3. Mix the coated modified montmorillonite and zinc chloride solution, ultrasonically disperse for 60-80 min, raise the temperature of the reaction system to 70-80℃, keep it at the temperature for 4-5 h, and then perform post-treatment to obtain the modified montmorillonite.

[0014] The synthesis reaction mechanism of modified montmorillonite is as follows: During the reaction, tetrabutyl titanate hydrolyzes in ethanol and acetic acid solutions to form a titanium-based sol. Sodium-based montmorillonite is then dispersed in the titanium-based sol, which undergoes dehydration condensation to form a titanium-oxygen network coating on the sodium-based montmorillonite. Under high-temperature oxidation, the titanium-oxygen network crystallizes into anatase TiO2, while the interlayer dehydration and shrinkage of montmorillonite enhances its mechanical intercalation with TiO2, thus preparing titanium-modified montmorillonite. Sodium hexametaphosphate acts as a dispersant to prevent the aggregation of hexamethyl melamine. Simultaneously, under acidic conditions, hexamethyl melamine condenses with the active hydroxyl groups on the sodium-based montmorillonite particles, forming a three-dimensional network structure that coats the montmorillonite particles, thus preparing coated modified montmorillonite. The interlayer Na... +The ammonium bromide ions in hexadecyltrimethylammonium bromide exchange with each other, and the ammonium bromide ions insert into the interlayer through hydrophobic alkyl chains, expanding the interlayer spacing. 2+ Modified montmorillonite was prepared by adsorbing onto the surface and interlayer of montmorillonite through electrostatic interaction and forming coordination bonds with oxygen vacancies on the TiO2 surface.

[0015] Further, in step A1, the ratio of tetrabutyl titanate, anhydrous ethanol, acetic acid solution, and sodium montmorillonite is 4g:20mL:10mL:7-8g. The acetic acid solution is composed of acetic acid, ethanol, and purified water in a ratio of 1g:5mL:5mL. The post-treatment includes: after the reaction is complete, raising the temperature of the reaction system to 70-80℃, evaporating the solvent, transferring the reactants to a tube furnace at a temperature of 450-480℃, oxidizing and calcining in air for 6-8 hours, pulverizing, and passing through a 100-mesh sieve to obtain titanium-modified montmorillonite.

[0016] Further, in step A2, the ratio of titanium-modified montmorillonite, sodium hexametaphosphate, hexamethyl melamine, and deionized water is 25-30g:0.6-0.8g:8-10g:500mL, the concentration of hydrochloric acid is 2-3mol / L, and the post-treatment includes: after the reaction is complete, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed with purified water until neutral and then dried, the filter cake is transferred to a drying oven at a temperature of 65-75℃ and dried to constant weight to obtain coated modified montmorillonite.

[0017] Further, in step A3, the ratio of the coated modified montmorillonite to the zinc chloride solution is 1g:10mL. The zinc chloride solution is a zinc chloride solution with pH=4, and the zinc chloride solution is composed of zinc chloride, hexadecyltrimethylammonium bromide, and purified water in a ratio of 1.5g:0.8g:100mL. The post-treatment includes: after the reaction is completed, the temperature of the reaction system is lowered to room temperature, filtered, the filter cake is washed twice with purified water and then dried, the filter cake is transferred to a drying oven at a temperature of 95-105℃, and dried to constant weight in an air atmosphere to obtain modified montmorillonite.

[0018] Furthermore, epoxy-modified polysiloxanes are obtained through the following steps: B1. Mix and stir octamethylcyclotetrasiloxane, trifluoropropylcyclotetrasiloxane, mercaptopropylmethyldimethoxysilane and catalyst, raise the temperature of the reaction system to 100-110℃, keep the reaction temperature for 2-3h, add 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction system, keep the reaction temperature for 60-80min, and then perform post-treatment to obtain fluorinated polysiloxane. B2. Mix fluorinated polysiloxane, epoxy butene, hexafluoroisopropanol and catalyst, and heat the reaction system to 50-56℃. Maintain the temperature for 60-80 min and then perform post-treatment to obtain epoxy-modified polysiloxane.

[0019] The synthesis reaction mechanism of epoxy-modified polysiloxanes is as follows:

[0020] During the reaction, under the action of a catalyst, octamethylcyclotetrasiloxane, trifluoropropylcyclotetrasiloxane, and mercaptopropylmethyldimethoxysilane molecules undergo ring-opening to form silanol-terminated polysiloxane chains and disilool-modified mercaptopropyl groups. Then, condensation occurs between silanols to form long polysiloxane segments. 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane acts as a capping agent, which, under the action of a catalyst, forms monosilanol silicon-containing compounds, thereby forming alcohol hydroxyl-terminated fluorinated polysiloxanes. Then, under the condition of azobisisobutyronitrile as a catalyst, the olefin double bond on the epoxide molecule adds to the mercapto group on the fluorinated polysiloxane molecular chain, forming epoxy groups on its molecule, thus preparing epoxy-modified polysiloxanes.

[0021] Further, in step B1, the ratio of octamethylcyclotetrasiloxane, trifluoropropylcyclotetrasiloxane, mercaptopropylmethyldimethoxysilane, catalyst, and 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane is 7-8g:4-5g:2.2-2.6g:1mL:2-3g. The catalyst is 40-50wt% sulfuric acid. The post-treatment includes: after the reaction is complete, the temperature of the reaction system is lowered to room temperature, 5wt% sodium bicarbonate solution is added to the reaction system to adjust the pH of the system to 7, the system is allowed to stand and separated, the upper oily substance is washed three times with purified water and then transferred to a rotary evaporator with a water bath temperature of 80-90℃, the pressure is reduced to 0.1MPa, and the low-boiling substances are removed by vacuum evaporation to obtain fluorinated polysiloxane.

[0022] Further, in step B2, the ratio of the fluorinated polysiloxane, epoxy butene, hexafluoroisopropanol and catalyst is 10-12g:3g:30mL:0.1g, the catalyst is azobisisobutyronitrile, and the post-treatment includes: after the reaction is completed, the reaction system is kept at 50-56℃, the negative pressure is drawn to 0.1MPa, and the low-boiling substances are removed by vacuum evaporation to obtain epoxy-modified polysiloxane.

[0023] This invention also proposes a method for preparing high-toughness UV-resistant PET fibers, wherein modified PET, modified polyester, modified montmorillonite, epoxy-modified polysiloxane and additives are added to a twin-screw extruder, melt-extruded into a spinning machine, and then subjected to secondary hot stretching after melt spinning to obtain UV-resistant PET fibers.

[0024] Furthermore, the additives consist of a dispersant, a lubricant, a plasticizer, an antistatic agent, and an antioxidant in a weight ratio of 2:1:3:2:2. The dispersant is stearate, the lubricant is ethylene bis-stearamide, the plasticizer is phthalate, the antistatic agent is antistatic agent SN, and the antioxidant is antioxidant 1010. The twin-screw extruder has four temperature zones from the feed end to the discharge end with temperatures of 330℃, 335℃, 340℃, and 340℃ respectively. The spinning machine has an aspect ratio of 20:1, a spinneret orifice diameter of 0.3mm, 36 orifices, a spinning speed of 800m / min, a melt spinning temperature of 340℃, a primary hot drawing temperature of 150-160℃ with a draw ratio of 2.5-2.8, and a secondary hot drawing temperature of 170-180℃ with a draw ratio of 3.8-4.2.

[0025] The present invention has the following beneficial effects: 1. This invention involves modifying PET and mixing it with modified polyester and epoxy-modified polysiloxane. Then, using modified montmorillonite as a heterogeneous nucleation site, the PET molecular chains are induced to align highly along the stretching direction, forming a highly oriented lamellar structure. This increases the crystallinity of the polyester fiber. The oriented crystallization increases the grain size along the stretching direction and decreases it perpendicular to the stretching direction, reducing grain boundary defects and improving crystal perfection. While increasing the tensile strength of the polyester fiber, it maintains a high elongation at break. The highly oriented lamellar structure of the PET fiber works synergistically with the modified montmorillonite and modified polyester to reduce the penetration path of ultraviolet rays, thereby improving the UV resistance and moisture absorption and quick-drying properties of the PET fiber.

[0026] 2. This invention modifies PET with allyl polyethylene glycol by modifying the PET chain segments with long-chain polyethylene glycol. The flexible segments of polyethylene glycol disrupt the regularity of the PET molecular chain, and the polyether segments have strong hydrophilicity, further improving the hygroscopic properties of PET. The modified polyester is prepared from sebacic acid, diethylene glycol, and 3-amino-1,5-pentanediol as raw materials through high-temperature esterification. The long fatty chains and ether bonds of sebacic acid, along with the rotational freedom of the diethylene glycol segments in the modified polyester through the ether bonds, endow the molecular chain with a certain degree of flexibility. 3,5-Bis(tert-butyl) 4-hydroxyphenylpropionyl chloride, as a hindered phenol, undergoes a nucleophilic substitution reaction between its acyl chloride group and the amino group of the linear polyester to form a stable chemical bond. This introduces the UV-resistant group of the hindered phenol into the modified polyester molecular chain, thereby significantly improving the UV resistance and elongation of the UV-resistant PET fiber. The hydroxyl and ether bonds in the modified polyester adsorb moisture through hydrogen bonding. The layered structure of the modified montmorillonite and the hydrophilic groups of the modified polyester work synergistically to form micron-nano-scale moisture transport channels, increasing the moisture diffusion coefficient of the material and thus improving its moisture absorption and quick-drying properties.

[0027] 3. This invention involves modifying titanium dioxide with sodium-based montmorillonite, then coating it with a hexamethyl melamine coating and zinc oxide, to prepare titanium / zinc modified and organically coated montmorillonite. This improves the dispersibility of the modified montmorillonite in PET fibers. The montmorillonite nanosheets form a "maze effect" in the PET matrix, extending the ultraviolet penetration path. TiO2 is dispersed on the surface of the sheets, enhancing the full-band reflection efficiency. Zn can quench free radicals generated by PET photodegradation, delaying fiber aging. Combined with modified polyester, it improves the UV resistance of PET fibers. The epoxy groups in the epoxy-modified polysiloxane have certain reactivity. During melt extrusion, the epoxy groups can chemically react with the active groups in the modified PET, modified polyester, and other components to form chemical bonds, enhancing the interaction forces between molecular chains and making the internal structure of the fiber more compact and regular. Therefore, under external tensile force, the fiber's UV resistance is improved. It can better transfer and disperse stress, reduce stress concentration, and thus improve the breaking strength of the fiber. The polysiloxane segments themselves have excellent flexibility, and epoxy-modified polysiloxane retains this characteristic. When the fiber is stretched, the flexible segments of epoxy-modified polysiloxane can stretch and deform, providing the fiber with a certain deformation space, so that the fiber can withstand greater elongation deformation before breaking, thereby improving the breaking elongation. The CF bond energy of the fluorine-containing groups introduced in the preparation process of epoxy-modified polysiloxane is high, which can absorb and scatter ultraviolet rays, reduce the damaging effect of ultraviolet rays on the fiber molecular chain, and further improve the material's resistance to ultraviolet aging. In addition, the siloxane segments in epoxy-modified polysiloxane have low surface energy, which can reduce the surface tension of the fiber, making the fiber surface easier to wet with water, and also facilitating the spread and penetration of water on the fiber surface, thereby improving the fiber's moisture absorption and quick-drying performance. Detailed Implementation

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] In this application, the sodium montmorillonite was selected from Lingshou County Wanzhu Mineral Products Co., Ltd., with an effective ingredient content of 90% and a density of 2-3 g / cm³. 3 Its hardness is 1-2; In this application, PET refers to commercially available polyester chips, grade CR-8828, specification 1100KGmm, brand Changzhou Huarun; In this application, allyl polyethylene glycol is a commercially available product with the specification APEG-700, a hydroxyl value of 74-88 mgKOH / g, and a pH value of 5-7. Example 1

[0030] This embodiment provides a method for preparing modified polyester, including the following steps: Step a: Preparation of linear polyester Weigh out 44.5g of sebacic acid, 10.6g of diethylene glycol, 11.9g of 3-amino-1,5-pentanediol and 4.45g of p-toluenesulfonic acid catalyst, add them to a reaction flask and stir. Raise the temperature of the reaction flask to 128℃ and keep it at that temperature until the acid value is 120mgKOH / g. Continue the reaction for 60min. Pour out the reactants while they are still hot, cool them down to solidify, and then crush them to obtain linear polyester.

[0031] Step b: Preparation of modified polyester Weigh 70g of linear polyester and 800mL of N,N-dimethylformamide and add them to an argon-protected reaction flask. Stir at room temperature until the linear polyester dissolves. Lower the temperature of the reaction flask to 0℃, add 5g of sodium bicarbonate to the reaction flask, and then add 7g of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride. Keep the reaction at this temperature for 2 hours. Raise the temperature of the reaction flask to room temperature, add purified water to the reaction system, stir and disperse for 30 minutes, filter, wash the filter cake three times with purified water, and then dry it. Transfer the filter cake to a drying oven at 60℃ and dry it to constant weight to obtain the modified polyester. Example 2

[0032] This embodiment provides a method for preparing modified polyester, including the following steps: Step a: Preparation of linear polyester Weigh out 44.5g of sebacic acid, 10.6g of diethylene glycol, 11.9g of 3-amino-1,5-pentanediol and 4.45g of p-toluenesulfonic acid catalyst, add them to a reaction flask and stir. Raise the temperature of the reaction flask to 131℃ and keep the reaction at this temperature until the acid value reaches 120mgKOH / g. Continue the reaction for 70min. Pour out the reactants while they are still hot, cool them down to solidify, and then crush them to obtain linear polyester.

[0033] Step b: Preparation of modified polyester Weigh 75g of linear polyester and 800mL of N,N-dimethylformamide and add them to an argon-protected reaction flask. Stir at room temperature until the linear polyester dissolves. Lower the temperature of the reaction flask to 3℃, add 6g of sodium bicarbonate, and then add 7.5g of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride. Keep the reaction at this temperature for 2.5h. Raise the temperature of the reaction flask to room temperature, add purified water to the reaction system, stir and disperse for 40min, filter, wash the filter cake three times with purified water, and then dry it. Transfer the filter cake to a drying oven at 65℃ and dry it to constant weight to obtain the modified polyester. Example 3

[0034] This embodiment provides a method for preparing modified polyester, including the following steps: Step a: Preparation of linear polyester Weigh out 44.5g of sebacic acid, 10.6g of diethylene glycol, 11.9g of 3-amino-1,5-pentanediol and 4.45g of p-toluenesulfonic acid catalyst, add them to a reaction flask and stir. Raise the temperature of the reaction flask to 135℃ and keep it at that temperature until the acid value is 120mgKOH / g. Continue the reaction for 80min. Pour out the reactants while they are still hot, cool them down to solidify, and then crush them to obtain linear polyester.

[0035] Step b: Preparation of modified polyester Weigh 80g of linear polyester and 800mL of N,N-dimethylformamide and add them to an argon-protected reaction flask. Stir at room temperature until the linear polyester dissolves. Lower the temperature of the reaction flask to 5℃, add 7g of sodium bicarbonate to the reaction flask, and then add 8g of 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride. Keep the reaction at this temperature for 3 hours. Raise the temperature of the reaction flask to room temperature, add purified water to the reaction system, stir and disperse for 50 minutes, filter, wash the filter cake three times with purified water, and then dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain the modified polyester. Example 4

[0036] This embodiment provides a method for preparing epoxy-modified polysiloxane, including the following steps: Step ①: Preparation of fluorinated polysiloxane Weigh out 70g of octamethylcyclotetrasiloxane, 40g of trifluoropropylcyclotetrasiloxane, 22g of mercaptopropylmethyldimethoxysilane, and 10mL of 40wt% sulfuric acid and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 100℃. Keep the reaction at this temperature for 2h. Add 20g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction flask and keep the reaction at this temperature for 60min. Lower the temperature of the reaction flask to room temperature and add 5wt% sodium bicarbonate solution to adjust the pH of the system to 7. Allow the mixture to stand and separate the layers. Wash the upper oily layer three times with purified water and transfer it to a rotary evaporator with a water bath temperature of 80℃. Apply a negative pressure of 0.1MPa and remove low-boiling substances by vacuum evaporation to obtain fluorinated polysiloxane.

[0037] Step ②: Preparation of epoxy-modified polysiloxane Weigh out 100g of fluorinated polysiloxane, 30g of epoxy butene, 300mL of hexafluoroisopropanol and 1g of catalyst azobisisobutyronitrile and add them to a reaction flask and stir. The temperature of the reaction flask is raised to 50℃ and the reaction is maintained at this temperature for 60min. The reaction flask is then kept at 50℃ and the negative pressure is reduced to 0.1MPa. Low-boiling substances are removed by vacuum evaporation to obtain epoxy-modified polysiloxane. Example 5

[0038] This embodiment provides a method for preparing epoxy-modified polysiloxane, including the following steps: Step ①: Preparation of fluorinated polysiloxane Weigh out 75g of octamethylcyclotetrasiloxane, 45g of trifluoropropylcyclotetrasiloxane, 24g of mercaptopropylmethyldimethoxysilane, and 10mL of 45wt% sulfuric acid and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 105℃. Maintain the temperature for 2.5h. Add 25g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction flask and maintain the temperature for 70min. Lower the temperature of the reaction flask to room temperature and add 5wt% sodium bicarbonate solution to adjust the pH of the system to 7. Allow the mixture to stand and separate the layers. Wash the upper oily layer three times with purified water and transfer it to a rotary evaporator with a water bath temperature of 85℃. Apply a negative pressure of 0.1MPa and remove low-boiling substances by vacuum evaporation to obtain fluorinated polysiloxane.

[0039] Step ②: Preparation of epoxy-modified polysiloxane Weigh out 110g of fluorinated polysiloxane, 30g of epoxy butene, 300mL of hexafluoroisopropanol and 1g of catalyst azobisisobutyronitrile and add them to the reaction flask and stir. The temperature of the reaction flask is raised to 53℃ and the reaction is maintained at this temperature for 70min. The reaction flask is then kept at 53℃ and the negative pressure is reduced to 0.1MPa. Low-boiling substances are removed by vacuum evaporation to obtain epoxy-modified polysiloxane.

[0040] Example 6 This embodiment provides a method for preparing epoxy-modified polysiloxane, including the following steps: Step ①: Preparation of fluorinated polysiloxane Weigh out 80g of octamethylcyclotetrasiloxane, 50g of trifluoropropylcyclotetrasiloxane, 26g of mercaptopropylmethyldimethoxysilane, and 10mL of 50wt% sulfuric acid and add them to a reaction flask. Stir the mixture and raise the temperature of the reaction flask to 110℃. Keep the reaction at this temperature for 3h. Add 30g of 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction flask and keep the reaction at this temperature for 80min. Lower the temperature of the reaction flask to room temperature and add 5wt% sodium bicarbonate solution to adjust the pH of the system to 7. Allow the mixture to stand and separate the layers. Wash the upper oily layer three times with purified water and transfer it to a rotary evaporator with a water bath temperature of 90℃. Apply a negative pressure of 0.1MPa and remove low-boiling substances by vacuum evaporation to obtain fluorinated polysiloxane.

[0041] Step ②: Preparation of epoxy-modified polysiloxane Weigh out 120g of fluorinated polysiloxane, 30g of epoxy butene, 300mL of hexafluoroisopropanol and 1g of catalyst azobisisobutyronitrile and add them to the reaction flask and stir. The temperature of the reaction flask is raised to 56℃ and the reaction is maintained at this temperature for 80min. The reaction flask is then kept at 56℃ and the negative pressure is reduced to 0.1MPa. Low-boiling substances are removed by vacuum evaporation to obtain epoxy-modified polysiloxane.

[0042] Example 7 This embodiment provides a method for preparing modified montmorillonite, including the following steps: Step I: Preparation of titanium-modified montmorillonite Acetic acid, ethanol and purified water were mixed evenly at a ratio of 1g:5mL:5mL to obtain an acetic acid solution. Weigh out 40g of tetrabutyl titanate and 200mL of anhydrous ethanol and add them to the reaction flask. Stir and add 100mL of acetic acid solution to the reaction flask. Stir and disperse at room temperature for 20min. Add 70g of sodium montmorillonite to the reaction flask and stir and disperse for 60min. Raise the temperature of the reaction flask to 70℃, evaporate the solvent, transfer the reactants to a tube furnace at 450℃, and oxidize and calcine in air for 6h. Crush and pass through a 100-mesh sieve to obtain titanium-modified montmorillonite.

[0043] Step II: Preparation of coated modified montmorillonite; Weigh out 50g of titanium-modified montmorillonite, 1.2g of sodium hexametaphosphate, 16g of hexamethyl melamine, and 1000mL of deionized water and add them to a reaction flask. Stir and disperse at room temperature for 60min. Add 2mol / L hydrochloric acid to the reaction flask to adjust the pH of the system to 5. Raise the temperature of the reaction flask to 70℃ and keep it at that temperature for 5h. Lower the temperature of the reaction flask to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 65℃ and dry it to constant weight to obtain coated modified montmorillonite.

[0044] Step III: Preparation of modified montmorillonite Zinc chloride, hexadecyltrimethylammonium bromide, and purified water were mixed at a ratio of 1.5 g: 0.8 g: 100 mL. Hydrochloric acid was added to the reaction system to adjust the pH to 4, thus obtaining a zinc chloride solution. Weigh out 50g of the modified montmorillonite and 500mL of zinc chloride solution, add them to the reaction flask and mix. Disperse the mixture by sonication for 60min. Raise the temperature of the reaction flask to 70℃ and keep it at that temperature for 4h. Lower the temperature of the reaction flask to room temperature and filter. Wash the filter cake twice with purified water and dry it. Transfer the filter cake to a drying oven at 95℃ and dry it to constant weight in air to obtain the modified montmorillonite.

[0045] Example 8 This embodiment provides a method for preparing modified montmorillonite, including the following steps: Step I: Preparation of titanium-modified montmorillonite Acetic acid, ethanol and purified water were mixed evenly at a ratio of 1g:5mL:5mL to obtain an acetic acid solution. Weigh out 40g of tetrabutyl titanate and 200mL of anhydrous ethanol and add them to the reaction flask. Stir. Add 100mL of acetic acid solution to the reaction flask and stir to disperse at room temperature for 25min. Add 75g of sodium montmorillonite to the reaction flask and stir to disperse for 70min. Raise the temperature of the reaction flask to 75℃, evaporate the solvent, transfer the reactants to a tube furnace at 465℃, and oxidize and calcine in air for 7h. Crush and pass through a 100-mesh sieve to obtain titanium-modified montmorillonite.

[0046] Step II: Preparation of coated modified montmorillonite; Weigh out 55g of titanium-modified montmorillonite, 1.4g of sodium hexametaphosphate, 18g of hexamethyl melamine, and 1000mL of deionized water and add them to a reaction flask. Stir and disperse at room temperature for 70min. Add 2.5mol / L hydrochloric acid to the reaction flask to adjust the pH of the system to 5.3. Raise the temperature of the reaction flask to 75℃ and keep it at that temperature for 5.5h. Lower the temperature of the reaction flask to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 70℃ and dry it to constant weight to obtain coated modified montmorillonite.

[0047] Step III: Preparation of modified montmorillonite Zinc chloride, hexadecyltrimethylammonium bromide, and purified water were mixed at a ratio of 1.5 g: 0.8 g: 100 mL. Hydrochloric acid was added to the reaction system to adjust the pH to 4, thus obtaining a zinc chloride solution. Weigh out 50g of the modified montmorillonite and 500mL of zinc chloride solution, add them to the reaction flask and mix. Disperse the mixture by sonication for 70min. Raise the temperature of the reaction flask to 75℃ and keep it at that temperature for 4.5h. Lower the temperature of the reaction flask to room temperature, filter the mixture, wash the filter cake twice with purified water and dry it. Transfer the filter cake to a drying oven at 100℃ and dry it to constant weight in air to obtain the modified montmorillonite.

[0048] Example 9 This embodiment provides a method for preparing modified montmorillonite, including the following steps: Step I: Preparation of titanium-modified montmorillonite Acetic acid, ethanol and purified water were mixed evenly at a ratio of 1g:5mL:5mL to obtain an acetic acid solution. Weigh out 40g of tetrabutyl titanate and 200mL of anhydrous ethanol and add them to the reaction flask. Stir and add 100mL of acetic acid solution to the reaction flask. Stir and disperse at room temperature for 30min. Add 80g of sodium montmorillonite to the reaction flask and stir and disperse for 80min. Raise the temperature of the reaction flask to 80℃, evaporate the solvent, transfer the reactants to a tube furnace at 480℃, and oxidize and calcine in air atmosphere for 8h. Crush and pass through a 100-mesh sieve to obtain titanium-modified montmorillonite.

[0049] Step II: Preparation of coated modified montmorillonite; Weigh out 60g of titanium-modified montmorillonite, 1.6g of sodium hexametaphosphate, 20g of hexamethyl melamine, and 1000mL of deionized water and add them to a reaction flask. Stir and disperse at room temperature for 80min. Add 3mol / L hydrochloric acid to the reaction flask to adjust the pH of the system to 5.5. Raise the temperature of the reaction flask to 80℃ and keep it at that temperature for 6h. Lower the temperature of the reaction flask to room temperature, filter, wash the filter cake with purified water until neutral, and then dry it. Transfer the filter cake to a drying oven at 75℃ and dry it to constant weight to obtain coated modified montmorillonite.

[0050] Step III: Preparation of modified montmorillonite Zinc chloride, hexadecyltrimethylammonium bromide, and purified water were mixed at a ratio of 1.5 g: 0.8 g: 100 mL. Hydrochloric acid was added to the reaction system to adjust the pH to 4, thus obtaining a zinc chloride solution. Weigh out 50g of the modified montmorillonite and 500mL of zinc chloride solution, add them to the reaction flask and mix. Disperse the mixture by sonication for 80min. Raise the temperature of the reaction flask to 80℃ and keep it at that temperature for 5h. Lower the temperature of the reaction flask to room temperature and filter. Wash the filter cake twice with purified water and dry it. Transfer the filter cake to a drying oven at 105℃ and dry it to constant weight in air to obtain the modified montmorillonite.

[0051] Example 10 This embodiment provides a method for preparing high-toughness, UV-resistant PET fibers, including the following steps: S1. Material preparation PET, allyl polyethylene glycol, and initiator dicumyl peroxide were added to a torque rheometer at a weight ratio of 20:1:0.1 at 245°C. The speed was set to 50 r / min, and the mixture was melted and mixed for 8 min. The product was then discharged to obtain modified PET. Calcium stearate, ethylene bis-stearamide, diisobutyl phthalate, antistatic agent SN and antioxidant 1010 are mixed in a weight ratio of 2:1:3:2:2 to obtain the additives. Weigh out the following by weight: 55 parts of modified PET, 30 parts of modified polyester prepared in Example 1, 10 parts of modified montmorillonite prepared in Example 7, 20 parts of epoxy-modified polysiloxane prepared in Example 4, and 3 parts of additives, and mix them to obtain a mixture.

[0052] S2. Preparation of UV-resistant PET fiber crude product The mixture is added to a twin-screw extruder, and the temperatures of the four temperature zones from the feed end to the discharge end of the twin-screw extruder are set to 330℃, 335℃, 340℃, and 340℃ respectively. The mixture is melt-extruded into a spinning machine with a length-to-diameter ratio of 20:1, a spinneret orifice diameter of 0.3mm, and 36 orifices. The melt spinning temperature is set to 340℃ and the spinning speed is 800m / min. The melt spinning process yields a UV-resistant PET fiber preform.

[0053] S3, Preparation of UV-resistant PET fibers A parallel drawing machine was selected, and the drawing temperature was set to 150℃ and the drawing ratio to 2.5 times for one drawing. Then, the drawing machine temperature was raised to 170℃ and the drawing ratio was set to 3.8 times for a second drawing to obtain UV-resistant PET fiber.

[0054] Example 11 This embodiment provides a method for preparing high-toughness, UV-resistant PET fibers, including the following steps: S1. Material preparation PET, allyl polyethylene glycol, and initiator dicumyl peroxide were added to a torque rheometer at a weight ratio of 20:1:0.1 at 250°C. The speed was set to 55 r / min, and the mixture was melted and mixed for 9 min. The product was then discharged to obtain modified PET. Zinc stearate, ethylene bis-stearamide, dioctyl phthalate, antistatic agent SN and antioxidant 1010 are mixed in a weight ratio of 2:1:3:2:2 to obtain the additives. Weigh out the following by weight: 57 parts of modified PET, 33 parts of modified polyester prepared in Example 2, 13 parts of modified montmorillonite prepared in Example 8, 25 parts of epoxy-modified polysiloxane prepared in Example 5, and 4 parts of additives, and mix them to obtain a mixture.

[0055] S2. Preparation of UV-resistant PET fiber crude product The mixture is added to a twin-screw extruder, and the temperatures of the four temperature zones from the feed end to the discharge end of the twin-screw extruder are set to 330℃, 335℃, 340℃, and 340℃ respectively. The mixture is melt-extruded into a spinning machine with a length-to-diameter ratio of 20:1, a spinneret orifice diameter of 0.3mm, and 36 orifices. The melt spinning temperature is set to 340℃ and the spinning speed is 800m / min. The melt spinning process yields a UV-resistant PET fiber preform.

[0056] S3, Preparation of UV-resistant PET fibers A parallel drawing machine was selected, and the drawing temperature was set to 155℃ and the drawing ratio to 2.7 times for one drawing. Then, the drawing machine temperature was raised to 175℃ and the drawing ratio was set to 4.0 times for a second drawing to obtain UV-resistant PET fiber.

[0057] Example 12 This embodiment provides a method for preparing high-toughness, UV-resistant PET fibers, including the following steps: S1. Material preparation PET, allyl polyethylene glycol, and initiator dicumyl peroxide were added to a torque rheometer at a weight ratio of 20:1:0.1 at 255°C. The speed was set to 60 r / min, and the mixture was melted and mixed for 10 min. The product was then discharged to obtain modified PET. Sodium stearate, ethylene bis-stearamide, dibutyl phthalate, antistatic agent SN and antioxidant 1010 are mixed in a weight ratio of 2:1:3:2:2 to obtain the additives. Weigh out the following by weight: 60 parts of modified PET, 35 parts of modified polyester prepared in Example 3, 16 parts of modified montmorillonite prepared in Example 9, 30 parts of epoxy-modified polysiloxane prepared in Example 6, and 5 parts of additives, and mix them to obtain a mixture.

[0058] S2. Preparation of UV-resistant PET fiber crude product The mixture is added to a twin-screw extruder, and the temperatures of the four temperature zones from the feed end to the discharge end of the twin-screw extruder are set to 330℃, 335℃, 340℃, and 340℃ respectively. The mixture is melt-extruded into a spinning machine with a length-to-diameter ratio of 20:1, a spinneret orifice diameter of 0.3mm, and 36 orifices. The melt spinning temperature is set to 340℃ and the spinning speed is 800m / min. The melt spinning process yields a UV-resistant PET fiber preform.

[0059] S3, Preparation of UV-resistant PET fibers A parallel drawing machine was selected, and the drawing temperature was set to 160℃ and the drawing ratio to 2.8 times for one drawing. Then, the drawing machine temperature was raised to 180℃ and the drawing ratio was set to 4.2 times for a second drawing to obtain UV-resistant PET fiber.

[0060] Comparative Example 1 The difference between this comparative example and Example 12 is that, in step S1, the modified PET in the mixture is replaced with an equal amount of PET.

[0061] Comparative Example 2 The difference between this comparative example and Example 12 is that, in the preparation of the modified polyester, ethylene glycol was used in place of sebacic acid and diethylene glycol in equal molar amounts.

[0062] Comparative Example 3 The difference between this comparative example and Example 12 is that, in the preparation of the modified montmorillonite, step II is omitted, and the titanium-modified montmorillonite in step I is used instead of the coated modified montmorillonite in step III.

[0063] Comparative Example 4 The difference between this comparative example and Example 12 is that step ② is omitted in the preparation of the epoxy-modified polysiloxane used.

[0064] Performance testing: The breaking strength and elongation at break of the UV-resistant PET fibers prepared in Examples 10-12 and Comparative Examples 1-4 were determined according to the standard GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments". The UV-resistant PET fibers prepared in Examples 10-12 and Comparative Examples 1-4 were subjected to irradiation at 60°C and an intensity of 0.77 W / m². 2 Exposure to ultraviolet light at a wavelength of 340nm for 168 hours, according to the formula In the formula, X1 represents the fracture strength and elongation at break of the sample after ultraviolet irradiation, and X0 represents the fracture strength and elongation at break of the sample before irradiation. The retention rate of the fracture strength and elongation at break of the sample is determined. The UV-resistant PET fibers prepared in Examples 10-12 and Comparative Examples 1-4 were blended to prepare textile yarns. The yarns were spun with a warp density of 100 threads / inch and a weft density of 80 threads / inch to prepare textile fiber fabrics. The water absorption rate and drying rate of the samples were determined according to the standard GB / T 21655.1-2023 "Evaluation of the moisture absorption and quick-drying properties of textiles - Part 1: Single combination test method". The specific test data are shown in Table 1 below.

[0065] Table 1 - Performance Test Data of Samples

[0066] Data Analysis: Comparative analysis of the data in Table 1 shows that the UV-resistant PET fiber prepared by this invention has a breaking strength of 7.42 cN / detx and a breaking elongation of 48.3%. After UV aging, the breaking strength retention rate reaches 97.1% and the breaking elongation retention rate reaches 97.3%. The fabric sample prepared with the UV-resistant PET fiber has a water absorption rate of 125% and a drying rate of 0.42 g / h. All performance test data are superior to the comparative example. This indicates that this invention uses modified montmorillonite as a heterogeneous nucleation point to induce the PET molecular chains composed of modified PET, modified polyester, and epoxy-modified polysiloxane to be highly oriented along the stretching direction. This improves the breaking strength of PET fiber while maintaining a high breaking elongation, thereby enhancing the UV resistance and moisture absorption and quick-drying properties of PET fiber.

[0067] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high-toughness, UV-resistant PET fiber, characterized in that, The high-toughness UV-resistant PET fiber is composed of modified PET, modified polyester, modified montmorillonite, epoxy-modified polysiloxane, and additives in a weight ratio of 55-60:30-35:10-16:20-30:3-5. The modified polyester is prepared as follows: sebacic acid, diethylene glycol, 3-amino-1,5-pentanediol and catalyst are mixed, the reaction system temperature is raised to 128-135℃, and the reaction is maintained until the acid value is 120mgKOH / g. The reaction is continued for 60-80min, and then post-treatment is performed to obtain linear polyester; under an inert gas atmosphere, linear polyester and N,N-dimethylformamide are mixed and stirred at room temperature until the system is dissolved. The reaction system temperature is lowered to 0-5℃, catalyst is added to the reaction system, and then 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride is added to the reaction system. The reaction is maintained for 2-3h, and then post-treatment is performed to obtain modified polyester.

2. The high-toughness UV-resistant PET fiber according to claim 1, characterized in that, The molar ratio of sebacic acid, diethylene glycol, and 3-amino-1,5-pentanediol is 2.2 mol: 1 mol: 1 mol. The weight ratio of the catalyst to sebacic acid is 1:

10. The catalyst is p-toluenesulfonic acid. The post-treatment includes: after the reaction is complete, pouring out the reactants while hot, cooling and solidifying, and pulverizing to obtain a linear polyester. The molar ratio of the linear polyester, N,N-dimethylformamide, catalyst, and 3,5-bis(tert-butyl)-4-hydroxyphenylpropionyl chloride is 7-8 g: 80 mL: 0.5-0.7 g: 0.7-0.8 g.

3. The high-toughness UV-resistant PET fiber according to claim 1, characterized in that, The modified PET is prepared by adding PET, allyl polyethylene glycol and initiator into a torque rheometer and melting and mixing for 8-10 minutes to obtain modified PET.

4. The high-toughness UV-resistant PET fiber according to claim 3, characterized in that, The weight ratio of PET, allyl polyethylene glycol, and initiator is 20:1:0.1, the initiator is dicumyl peroxide, and the temperature of the torque rheometer is 245-255℃, and the rotation speed is 50-60 r / min.

5. The high-toughness UV-resistant PET fiber according to claim 1, characterized in that, Modified montmorillonite is obtained through the following steps: A1. Tetrabutyl titanate and anhydrous ethanol are mixed and stirred. Acetic acid solution is added to the reaction system and stirred and dispersed at room temperature for 20-30 min. Sodium montmorillonite is added to the reaction system and stirred and dispersed for 60-80 min. After post-treatment, titanium-modified montmorillonite is obtained. A2. Mix titanium-modified montmorillonite, sodium hexametaphosphate, hexamethyl melamine, and deionized water, and stir and disperse at room temperature for 60-80 min. Add hydrochloric acid to the reaction system to adjust the pH of the system to 5-5.

5. Raise the temperature of the reaction system to 70-80℃ and keep the reaction at this temperature for 5-6 h. After post-treatment, the coated modified montmorillonite is obtained. A3. Mix the coated modified montmorillonite and zinc chloride solution, ultrasonically disperse for 60-80 min, raise the temperature of the reaction system to 70-80℃, keep it at the temperature for 4-5 h, and then perform post-treatment to obtain the modified montmorillonite.

6. The high-toughness UV-resistant PET fiber according to claim 5, characterized in that, In step A1, the ratio of tetrabutyl titanate, anhydrous ethanol, acetic acid solution, and sodium montmorillonite is 4g:20mL:10mL:7-8g, and the acetic acid solution is composed of acetic acid, ethanol, and purified water in a ratio of 1g:5mL:5mL. In step A2, the ratio of titanium-modified montmorillonite, sodium hexametaphosphate, hexamethyl melamine, and deionized water is 25-30g:0.6-0.8g:8-10g:500mL, and the concentration of hydrochloric acid is 2-3mol / L. In step A3, the ratio of coated modified montmorillonite and zinc chloride solution is 1g:10mL, and the zinc chloride solution is a zinc chloride solution with pH=4, composed of zinc chloride, hexadecyltrimethylammonium bromide, and purified water in a ratio of 1.5g:0.8g:100mL.

7. The high-toughness UV-resistant PET fiber according to claim 1, characterized in that, Epoxy-modified polysiloxanes are obtained through the following steps: B1. Mix and stir octamethylcyclotetrasiloxane, trifluoropropylcyclotetrasiloxane, mercaptopropylmethyldimethoxysilane and catalyst, raise the temperature of the reaction system to 100-110℃, keep the reaction temperature for 2-3h, add 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane to the reaction system, keep the reaction temperature for 60-80min, and then perform post-treatment to obtain fluorinated polysiloxane. B2. Mix fluorinated polysiloxane, epoxy butene, hexafluoroisopropanol and catalyst, and heat the reaction system to 50-56℃. Maintain the temperature for 60-80 min and then perform post-treatment to obtain epoxy-modified polysiloxane.

8. The high-toughness UV-resistant PET fiber according to claim 7, characterized in that, In step B1, the ratio of octamethylcyclotetrasiloxane, trifluoropropylcyclotetrasiloxane, mercaptopropylmethyldimethoxysilane, catalyst, and 1,3-bis(4-hydroxybutyl)tetramethyldisiloxane is 7-8g:4-5g:2.2-2.6g:1mL:2-3g, and the catalyst is 40-50wt% sulfuric acid; in step B2, the ratio of fluorinated polysiloxane, epoxybutene, hexafluoroisopropanol, and catalyst is 10-12g:3g:30mL:0.1g, and the catalyst is azobisisobutyronitrile.

9. A method for preparing high-toughness UV-resistant PET fiber as described in any one of claims 1-8, characterized in that, Modified PET, modified polyester, modified montmorillonite, epoxy-modified polysiloxane, and additives are added to a twin-screw extruder, melt-extruded into a spinning machine, and then subjected to secondary hot stretching after melt spinning to obtain UV-resistant PET fibers.

10. The method for preparing a high-toughness UV-resistant PET fiber according to claim 9, characterized in that, The additives consist of a dispersant, a lubricant, a plasticizer, an antistatic agent, and an antioxidant in a weight ratio of 2:1:3:2:

2. The dispersant is stearate, the lubricant is ethylene bis-stearamide, the plasticizer is phthalate, the antistatic agent is antistatic agent SN, and the antioxidant is antioxidant 1010. The twin-screw extruder has four temperature zones from the feed end to the discharge end with temperatures of 330℃, 335℃, 340℃, and 340℃ respectively. The spinning machine has an aspect ratio of 20:1, a spinneret orifice diameter of 0.3mm, 36 orifices, a spinning speed of 800m / min, a melt spinning temperature of 340℃, a primary hot drawing temperature of 150-160℃ with a draw ratio of 2.5-2.8, and a secondary hot drawing temperature of 170-180℃ with a draw ratio of 3.8-4.2.

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