Antibacterial and ultraviolet resistant polyester fiber and melt spinning preparation method thereof

Abstract

The present application relates to the technical field of polyester fiber, in particular to an antibacterial and ultraviolet resistant polyester fiber and a melt spinning preparation method thereof. The fiber is prepared by melt spinning of antibacterial and ultraviolet resistant functional master batch and PET chip; the functional master batch is made of PET chip, interfacial directional compatibilized nano zinc oxide and hydroxyl-terminated low molecular weight PET oligomer. The interfacial directional compatibilized nano zinc oxide is combined by nano zinc oxide with silicon-containing surface compound and carboxyl-rich low molecular weight polyester affinity segment, and the carboxyl-rich low molecular weight polyester affinity segment is obtained by reaction of hydroxyl-terminated low molecular weight PET oligomer and 1,2,4-benzene tricarboxylic anhydride. The present application improves the dispersibility and interfacial stability of nano zinc oxide in PET melt by low-silicon surface regulation, polyester affinity segment anchoring and delayed addition of hydroxyl-terminated low molecular weight PET oligomer in the functional master batch stage, so that the fiber has antibacterial, ultraviolet resistant, spinnable and washable functions.

Description

Technical Field

[0001] This invention relates to the field of polyester fiber technology, and in particular to an antibacterial and UV-resistant polyester fiber and its melt spinning preparation method. Background Technology

[0002] Polyethylene terephthalate (PET) fiber is widely used in textiles, apparel, medical and health products, and outdoor equipment due to its excellent mechanical properties, chemical stability, and processability. However, ordinary polyester fibers lack natural antibacterial and UV-resistant properties, are prone to bacterial growth in humid environments, and are susceptible to photodegradation when exposed to sunlight for extended periods, limiting their application in high-end scenarios. To address this issue, existing technologies typically functionalize polyester fibers by introducing inorganic nanoparticles (such as nano-zinc oxide and nano-titanium dioxide) or organic antibacterial agents into the polyester matrix. Among these, nano-zinc oxide is considered an ideal modifying additive due to its dual antibacterial and UV-resistant properties.

[0003] However, nano-zinc oxide has extremely high surface energy, making it prone to agglomeration in polyester melt, forming micron-sized hard agglomerates. This leads to a sharp increase in filtration pressure during spinning, an increased risk of spinneret clogging, stress concentration points during fiber drafting, and a significant decrease in breaking strength. To improve dispersibility, existing technologies often use silane coupling agents to modify the surface of nano-zinc oxide. However, traditional small-molecule coupling agents have limited compatibility with the polyester matrix, weak interfacial bonding, and are prone to detachment during subsequent washing or use, resulting in insufficient functional durability. Furthermore, while coating nano-zinc oxide with a continuous, dense silica layer can inhibit agglomeration to some extent, it hinders the contact between nano-zinc oxide and bacteria and the absorption path of ultraviolet light, thus reducing functional efficiency. How to achieve uniform dispersion, stable interfacial bonding, and efficient functional output of nano-zinc oxide in the polyester matrix at low addition levels, while ensuring spinning processing stability and fiber mechanical properties, remains a pressing technical challenge in this field. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose an antibacterial and UV-resistant polyester fiber and its melt spinning preparation method, so as to solve the problems in existing nano-zinc oxide modified polyester fibers, such as the easy agglomeration of nanoparticles leading to poor spinning stability, weak interfacial bonding causing insufficient functional durability, and high filling or dense coating reducing antibacterial and UV-resistant efficiency and fiber mechanical properties.

[0005] To achieve the above objectives, the present invention provides an antibacterial and UV-resistant polyester fiber, comprising a polyethylene terephthalate matrix and interfacially oriented compatible nano-zinc oxide dispersed in the polyethylene terephthalate matrix. By mass percentage, the raw material for preparing the antibacterial and UV-resistant polyester fiber consists of 4.5%-7.5% antibacterial and UV-resistant functional masterbatch and the balance being polyethylene terephthalate chips.

[0006] The raw materials for preparing the antibacterial and UV-resistant functional masterbatch, by weight, consist of 2200-2600 parts of polyethylene terephthalate chips, 400-650 parts of interface-oriented compatible nano zinc oxide, and 45-85 parts of hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer.

[0007] The antibacterial and UV-resistant functional masterbatch is prepared by first adding the interface-directed compatibility nano zinc oxide to the melted polyethylene terephthalate chips and then adding the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer and continuing to mix.

[0008] The interface-oriented compatibility nano-zinc oxide is obtained by anchoring carboxyl-enriched low-molecular-weight polyester affinity segments onto the surface of silicon-oxygen modified nano-zinc oxide. The silicon-oxygen modified nano-zinc oxide is nano-zinc oxide with a surface containing 1.5%-4.0% silicon oxide compounds based on silicon dioxide. The carboxyl-enriched low-molecular-weight polyester affinity segments are obtained by reacting hydroxyl-terminated low-molecular-weight polyethylene terephthalate oligomers with 1,2,4-phenyltricarboxylic anhydride.

[0009] Preferably, the content of silicon oxide is 1.8%-3.3% based on silicon dioxide; and the organic grafting amount of the interface-oriented compatible nano zinc oxide is 11.8%-18.1%.

[0010] Preferably, the intrinsic viscosity of the polyethylene terephthalate chips is 0.6-0.7 dL / g; and the average particle size of the nano zinc oxide is 15-25 nm.

[0011] Preferably, the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer is prepared by the following method: 1000 parts of bis(2-hydroxyethyl) terephthalate and 1.5-2.5 parts of tetrabutyl titanate are taken, heated to 215-230°C under nitrogen protection and stirred for 50-70 min; then the pressure is reduced to 5 kPa within 30 min, and the reaction is carried out at 215-230°C and 5 kPa for 70-110 min. After the reaction is completed, the melt is cooled to 180°C and discharged to obtain the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer.

[0012] Preferably, the carboxyl-enriched low molecular weight polyester affinity segment is prepared by the following method: 500 parts of hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer, 95-140 parts of 1,2,4-benzenetricarboxylic anhydride and 1 part of tetrabutyl titanate are taken and stirred at 178-182°C under nitrogen protection for 70-90 min, then 2 parts of phosphoric acid are added and stirring is continued for 10 min, followed by removal of low-boiling substances at 160°C and 5 kPa for 30 min to obtain the carboxyl-enriched low molecular weight polyester affinity segment.

[0013] Preferably, the silicon-oxygen modified nano zinc oxide is prepared by the following method: 500 parts of nano zinc oxide, 4000 parts of anhydrous ethanol, 600 parts of deionized water and 90 parts of ammonia water with a mass fraction of 25% are taken and stirred at 35°C for 30 min; 31-60 parts of tetraethyl orthosilicate and 400 parts of anhydrous ethanol are mixed to form a dropping solution, and the dropping solution is added dropwise to the nano zinc oxide dispersion system within 40 min. After the addition is completed, stirring is continued at 35°C for 180 min; after the reaction is completed, the supernatant is discarded by centrifugation, and the resulting precipitate is washed successively with anhydrous ethanol and deionized water. After centrifugation again, the solid is collected, dried at 110°C for 8 h, and then heat-treated at 280°C for 30 min in a nitrogen atmosphere to obtain the silicon-oxygen modified nano zinc oxide.

[0014] Preferably, the interface-oriented compatibility nano-zinc oxide is prepared by the following method: 500 parts of silicon-oxygen modified nano-zinc oxide and 70-125 parts of carboxyl-enriched low molecular weight polyester affinity segments are added to a nitrogen-protected internal mixer and mixed at 195-210°C for 70-100 min; after discharge, the mixture is vacuum dried, pulverized, and passed through a 200-mesh sieve to obtain the interface-oriented compatibility nano-zinc oxide.

[0015] Preferably, the antibacterial and UV-resistant functional masterbatch is prepared by the following method: 2200-2600 parts of polyethylene terephthalate (PET) chips are dried under vacuum at 160°C and below 100Pa for 8 hours; the dried PET chips are added to the main feed port of a co-rotating twin-screw extruder for melt extrusion; 400-650 parts of interface-oriented compatible nano-zinc oxide are added from the first side feed port and mixed for 5-7 minutes; then 45-85 parts of hydroxyl-terminated low molecular weight PET oligomer are added from the second side feed port and mixed for another 4-5 minutes; subsequently, the mixture is vacuum degassed, extruded, cooled, and pelletized to obtain the antibacterial and UV-resistant functional masterbatch.

[0016] Furthermore, the present invention provides a melt spinning method for preparing antibacterial and UV-resistant polyester fibers, comprising the following steps:

[0017] (1) Prepare hydroxyl-terminated low molecular weight polyethylene terephthalate oligomers, and react a portion of the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomers with 1,2,4-benzenetricarboxylic anhydride to obtain carboxyl-enriched low molecular weight polyester affinity segments.

[0018] (2) A silicon oxide compound is formed on the surface of nano zinc oxide to obtain silicon oxide modified nano zinc oxide;

[0019] (3) The silicon-oxygen modified nano zinc oxide is mixed with the carboxyl-enriched low molecular weight polyester affinity segments, so that the carboxyl-enriched low molecular weight polyester affinity segments are anchored on the surface of the silicon-oxygen modified nano zinc oxide to obtain interface-oriented compatibility nano zinc oxide.

[0020] (4) After melting polyethylene terephthalate chips, first add the interface-oriented compatibility nano zinc oxide and mix, then add the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer and continue mixing to obtain antibacterial and UV-resistant functional masterbatch.

[0021] (5) The antibacterial and UV-resistant functional masterbatch is mixed with polyethylene terephthalate chips and melt-spun to obtain antibacterial and UV-resistant polyester fiber.

[0022] In this invention, the silicon oxide compound does not completely coat the nano-zinc oxide with a high-content continuous dense layer. Instead, the surface state of the nano-zinc oxide is controlled within a lower content range to reduce the tendency for hard agglomeration between particles while retaining the antibacterial and UV absorption activities of the nano-zinc oxide. The carboxyl groups in the low molecular weight polyester affinity segments enriched with carboxyl groups can form coordination, hydrogen bonds, or other interfacial interactions with the hydroxyl groups or metal sites on the surface of the nano-zinc oxide / silicon oxide compound. These polyester segments are compatible with the polyethylene terephthalate matrix, thus forming a stable interfacial transition layer between the functional particles and the polyester matrix. The hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer is added during the functional masterbatch preparation stage after the initial dispersion of the interfacially oriented compatible nano-zinc oxide. This further improves the local segment movement and interfacial wetting around the functional particles in the melt, reducing the risk of increased spinning filtration pressure and drawing defects.

[0023] The beneficial effects of this invention are:

[0024] (1) This invention constructs a silicon oxide compound with 1.5%-4.0% silica content on the surface of nano-zinc oxide, which reduces the surface energy of nanoparticles, inhibits hard agglomeration in the melt, and retains the active sites of nano-zinc oxide. Data shows that the functional particle D90 of Example 1 decreased to 0.58 μm, which is 53% lower than that of the unmodified comparative example 1 (1.24 μm). The increase in spinning filtration pressure decreased from 0.42 MPa to 0.16 MPa, and the breaking strength increased from 3.20 cN / dtex to 3.66 cN / dtex, thus solving the problem of decreased processing stability and mechanical properties caused by nanoparticle agglomeration.

[0025] (2) Carboxyl-enriched low-molecular-weight polyester affinity segments are used to anchor silicon-oxygen modified nano-zinc oxide. A stable interfacial transition layer is formed through chemical bonding and segment entanglement between the carboxyl groups and the polyester matrix. In Example 1, the antibacterial rates of Staphylococcus aureus and Escherichia coli after washing reached 92.1% and 90.4%, respectively, which were significantly improved compared with Comparative Example 3 (70.6% and 66.8%) without the use of carboxyl-enriched segments. This overcomes the defects of weak interfacial bonding and easy detachment of functional components in traditional small molecule coupling agents.

[0026] (3) Hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer was set as a post-addition component in the functional masterbatch mixing stage, so that it formed a synergistic compatibility effect with the polyester melt after the initial dispersion of nano zinc oxide. The UPF of Example 1 reached 72.4, which was significantly improved compared with Comparative Example 4 (61.7) and Comparative Example 5 (57.4), while the functional particle D90 remained at 0.58 μm, realizing the synergistic optimization of dispersibility, interfacial bonding and functional efficiency, and avoiding the performance loss of high filling or single modification methods. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0028] The main raw materials used are as follows: polyethylene terephthalate chips were SD500 from Sinopec Yizheng Chemical Fiber Co., Ltd., with an intrinsic viscosity of 0.66 dL / g; nano zinc oxide was XH-ZnO-20 from Shanghai Xiaohuang Nanotechnology Co., Ltd., with an average particle size of 20 nm; ammonia water was commercially available analytical grade ammonia water with a mass fraction of 25%; and phosphoric acid was commercially available analytical grade phosphoric acid with a mass fraction of 85%.

[0029] Example 1:

[0030] Step 1: Add 1000g of bis(2-hydroxyethyl) terephthalate and 2g of tetrabutyl titanate to a reactor equipped with a stirrer, nitrogen purging, and vacuum interface. After purging with nitrogen three times, raise the temperature to 220℃ and stir at 120r / min for 60min. Then, reduce the pressure inside the reactor to 5kPa within 30min and react at 220℃ and 5kPa for 90min, collecting the distilled ethylene glycol. After the reaction, cool the melt to 180℃ and discharge it to obtain hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer. Weigh 300g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and seal it for storage as a subsequent longer chain co-linking segment. Separately weigh 500g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and 120g of... 1,2,4-Benzotricarboxylic anhydride and 1g tetrabutyl titanate were added to a reaction vessel and stirred at 120r / min for 80min at 180℃ and under nitrogen protection. Then 2g phosphoric acid was added and stirring was continued for 10min. Subsequently, low-boiling substances were removed at 160℃ and 5kPa for 30min to obtain carboxyl-enriched low molecular weight polyester affinity segments.

[0031] Step 2: Add 500g of nano zinc oxide, 4000g of anhydrous ethanol, 600g of deionized water, and 90g of 25% ammonia solution to a stirred glass or stainless steel reactor. Stir at 800r / min for 30min at 35℃. Separately, mix 40g of tetraethyl orthosilicate and 400g of anhydrous ethanol to form a dropping solution. Add this solution dropwise to the nano zinc oxide dispersion system over 40min. After the addition is complete, continue stirring at 800r / min for 180min at 35℃. After the reaction is complete, centrifuge at 8000r / min for 20min and discard the supernatant. Wash the precipitate successively with 3000g of anhydrous ethanol and 2000g of deionized water, centrifuge again at 8000r / min for 20min, collect the solid, dry the solid at 110℃ for 8h, and then heat-treat at 280℃ for 30min in a nitrogen atmosphere to obtain silicon-oxygen modified nano zinc oxide.

[0032] Step 3: Take 500g of the silicon-oxygen modified nano zinc oxide obtained in Step 2 and 90g of the carboxyl-enriched low molecular weight polyester affinity segments obtained in Step 1 and add them to a nitrogen-protected internal mixer. Mix them at 205℃ and 60r / min for 80min. After discharge, vacuum dry them at 120℃ and 5kPa for 6h, pulverize them and pass them through a 200-mesh sieve to obtain interface-oriented compatibility nano zinc oxide.

[0033] Step 4: Take 2400g of polyethylene terephthalate (PET) chips and vacuum dry them at 160℃ and below 100Pa for 8 hours. Add the dried PET chips to the main feed port of a co-rotating twin-screw extruder. Set the screw zone temperature to 255℃, zone 2 to 265℃, zone 3 to 270℃, zone 4 to 272℃, and the die head temperature to 270℃. Set the screw speed to 150r / min. After the PET chips have been stably melted and extruded, add 500g of the interface-oriented compatibility nano zinc oxide obtained in Step 3 from the first side feed port and mix for 6 minutes. Then add 60g of the hydroxyl-terminated low molecular weight PET oligomer obtained in Step 1 from the second side feed port and continue mixing for 4 minutes. After vacuum degassing, extrusion, cooling, and pelletizing, obtain the antibacterial and UV-resistant functional masterbatch.

[0034] Step 5: Take 1200g of the antibacterial and UV-resistant functional masterbatch obtained in Step 4 and 18800g of polyethylene terephthalate chips, and vacuum dry them at 160℃ and below 100Pa for 8 hours respectively. Then, mix and melt spin them in a melt spinning machine. The temperature of the screw zone 1 is set to 276℃, the temperature of zone 2 is set to 282℃, the temperature of zone 3 is set to 286℃, the temperature of the spinning box is set to 286℃, the output of the metering pump is set to 40g / min, the spinneret has 36 holes, the diameter of the spinneret hole is 250μm, the side blowing temperature is 22℃, the side blowing speed is 40cm / s, the oiling amount is 6g / kg, and the winding speed is 1200m / min. The resulting raw filament is preheated by a hot roller at 85℃ and then stretched by 330%, and then heat-set at 170℃ to obtain antibacterial and UV-resistant polyester filament.

[0035] Example 2:

[0036] Step 1: Add 1000g of bis(2-hydroxyethyl) terephthalate and 2g of tetrabutyl titanate to a reactor equipped with a stirrer, nitrogen purging, and vacuum interface. After purging with nitrogen three times, raise the temperature to 215℃ and stir at 120r / min for 50min. Then, reduce the pressure inside the reactor to 5kPa within 30min and react at 215℃ and 5kPa for 70min, collecting the distilled ethylene glycol. After the reaction, cool the melt to 180℃ and discharge it to obtain hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer. Weigh 300g of hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer and seal it for storage as a subsequent longer chain co-linking segment. Separately weigh 500g of hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer and 140g of... 1,2,4-Benzotricarboxylic anhydride and 1g tetrabutyl titanate were added to a reaction vessel and stirred at 120r / min for 70min at 178℃ and under nitrogen protection. Then 2g phosphoric acid was added and stirring was continued for 10min. Subsequently, low-boiling substances were removed at 160℃ and 5kPa for 30min to obtain carboxyl-enriched low molecular weight polyester affinity segments.

[0037] Step 2: Add 500g of nano zinc oxide, 4000g of anhydrous ethanol, 600g of deionized water, and 90g of 25% ammonia solution to a stirred glass or stainless steel reactor. Stir at 800r / min for 30min at 35℃. Separately, mix 31g of tetraethyl orthosilicate and 400g of anhydrous ethanol to form a dropping solution. Add this solution dropwise to the nano zinc oxide dispersion system over 40min. After the addition is complete, continue stirring at 800r / min for 180min at 35℃. After the reaction is complete, centrifuge at 8000r / min for 20min and discard the supernatant. Wash the precipitate successively with 3000g of anhydrous ethanol and 2000g of deionized water, centrifuge again at 8000r / min for 20min, collect the solid, dry the solid at 110℃ for 8h, and then heat-treat at 280℃ for 30min in a nitrogen atmosphere to obtain silicon-oxygen modified nano zinc oxide.

[0038] Step 3: Take 500g of the silicon-oxygen modified nano zinc oxide obtained in Step 2 and 70g of the carboxyl-enriched low molecular weight polyester affinity segments obtained in Step 1 and add them to a nitrogen-protected internal mixer. Mix them at 195℃ and 60r / min for 70min. After discharge, vacuum dry them at 120℃ and 5kPa for 6h, pulverize them and pass them through a 200-mesh sieve to obtain interface-oriented compatibility nano zinc oxide.

[0039] Step 4: Take 2600g of polyethylene terephthalate (PET) chips and vacuum dry them at 160℃ and below 100Pa for 8 hours. Add the dried PET chips to the main feed port of a co-rotating twin-screw extruder. Set the screw zone temperature to 255℃, zone 2 to 265℃, zone 3 to 270℃, zone 4 to 272℃, and the die head temperature to 270℃. Set the screw speed to 150r / min. After the PET chips have been stably melted and extruded, add 400g of the interface-oriented compatibility nano zinc oxide obtained in Step 3 from the first side feed port and mix for 5 minutes. Then add 45g of the hydroxyl-terminated low molecular weight PET oligomer obtained in Step 1 from the second side feed port and continue mixing for 4 minutes. After vacuum degassing, extrusion, cooling, and pelletizing, obtain the antibacterial and UV-resistant functional masterbatch.

[0040] Step 5: Take 900g of the antibacterial and UV-resistant functional masterbatch obtained in Step 4 and 19100g of polyethylene terephthalate chips, and vacuum dry them at 160℃ and below 100Pa for 8 hours respectively. Then, mix and melt spin them in a melt spinning machine. The temperature of the first zone of the screw is set to 276℃, the temperature of the second zone is set to 282℃, the temperature of the third zone is set to 286℃, the temperature of the spinning box is set to 286℃, the output of the metering pump is set to 40g / min, the spinneret has 36 holes, the diameter of the spinneret hole is 250μm, the side blowing temperature is 22℃, the side blowing speed is 40cm / s, the oiling amount is 6g / kg, and the winding speed is 1200m / min. The resulting raw filament is preheated by an 85℃ hot roller and then stretched by 330%, and then heat-set at 170℃ to obtain antibacterial and UV-resistant polyester filament.

[0041] Example 3:

[0042] Step 1: Add 1000g of bis(2-hydroxyethyl) terephthalate and 2g of tetrabutyl titanate to a reactor equipped with a stirrer, nitrogen purging, and vacuum interface. After purging with nitrogen three times, raise the temperature to 225℃ and stir at 120r / min for 65min. Then, reduce the pressure inside the reactor to 5kPa within 30min and react at 225℃ and 5kPa for 100min, collecting the distilled ethylene glycol. After the reaction, cool the melt to 180℃ and discharge it to obtain hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer. Weigh 300g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and seal it for storage as a subsequent longer chain co-linking segment. Separately weigh 500g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and 105g of... 1,2,4-Benzotricarboxylic anhydride and 1g tetrabutyl titanate were added to a reaction vessel and stirred at 120r / min for 85min at 182℃ and under nitrogen protection. Then 2g phosphoric acid was added and stirring was continued for 10min. Subsequently, low-boiling substances were removed at 160℃ and 5kPa for 30min to obtain carboxyl-enriched low molecular weight polyester affinity segments.

[0043] Step 2: Add 500g of nano zinc oxide, 4000g of anhydrous ethanol, 600g of deionized water, and 90g of 25% ammonia solution to a stirred glass or stainless steel reactor. Stir at 800r / min for 30min at 35℃. Separately, mix 50g of tetraethyl orthosilicate and 400g of anhydrous ethanol to form a dropping solution. Add this solution dropwise to the nano zinc oxide dispersion system over 40min. After the addition is complete, continue stirring at 800r / min for 180min at 35℃. After the reaction is complete, centrifuge at 8000r / min for 20min and discard the supernatant. Wash the precipitate successively with 3000g of anhydrous ethanol and 2000g of deionized water, centrifuge again at 8000r / min for 20min, collect the solid, dry the solid at 110℃ for 8h, and then heat-treat at 280℃ for 30min in a nitrogen atmosphere to obtain silicon-oxygen modified nano zinc oxide.

[0044] Step 3: Take 500g of the silicon-oxygen modified nano zinc oxide obtained in Step 2 and 110g of the carboxyl-enriched low molecular weight polyester affinity segments obtained in Step 1 and add them to a nitrogen-protected internal mixer. Mix them at 205℃ and 60r / min for 90min. After discharge, vacuum dry them at 120℃ and 5kPa for 6h, pulverize them and pass them through a 200-mesh sieve to obtain interface-oriented compatibility nano zinc oxide.

[0045] Step 4: Take 2300g of polyethylene terephthalate (PET) chips and vacuum dry them at 160℃ and below 100Pa for 8 hours. Add the dried PET chips to the main feed port of a co-rotating twin-screw extruder. Set the screw zone temperature to 255℃, zone 2 to 265℃, zone 3 to 270℃, zone 4 to 272℃, and the die head temperature to 270℃. Set the screw speed to 150r / min. After the PET chips have been stably melted and extruded, add 550g of the interface-oriented compatibility nano zinc oxide obtained in Step 3 from the first side feed port and mix for 6 minutes. Then add 70g of the hydroxyl-terminated low molecular weight PET oligomer obtained in Step 1 from the second side feed port and continue mixing for 5 minutes. After vacuum degassing, extrusion, cooling, and pelletizing, obtain the antibacterial and UV-resistant functional masterbatch.

[0046] Step 5: Take 1200g of the antibacterial and UV-resistant functional masterbatch obtained in Step 4 and 18800g of polyethylene terephthalate chips, and vacuum dry them at 160℃ and below 100Pa for 8 hours respectively. Then, mix and melt spin them in a melt spinning machine. The temperature of the screw zone 1 is set to 276℃, the temperature of zone 2 is set to 282℃, the temperature of zone 3 is set to 286℃, the temperature of the spinning box is set to 286℃, the output of the metering pump is set to 40g / min, the spinneret has 36 holes, the diameter of the spinneret hole is 250μm, the side blowing temperature is 22℃, the side blowing speed is 40cm / s, the oiling amount is 6g / kg, and the winding speed is 1200m / min. The resulting raw filament is preheated by a hot roller at 85℃ and then stretched by 330%, and then heat-set at 170℃ to obtain antibacterial and UV-resistant polyester filament.

[0047] Example 4:

[0048] Step 1: Add 1000g of bis(2-hydroxyethyl) terephthalate and 2g of tetrabutyl titanate to a reactor equipped with a stirrer, nitrogen purging, and vacuum interface. After purging with nitrogen three times, raise the temperature to 230℃ and stir at 120r / min for 70min. Then, reduce the pressure inside the reactor to 5kPa within 30min and react at 230℃ and 5kPa for 110min, collecting the distilled ethylene glycol. After the reaction, cool the melt to 180℃ and discharge it to obtain hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer. Weigh 300g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and seal it for subsequent use as a longer chain co-linking segment. Separately weigh 500g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and 95g of... 1,2,4-Benzotricarboxylic anhydride and 1g tetrabutyl titanate were added to a reaction vessel and stirred at 120r / min for 90min at 182℃ and under nitrogen protection. Then 2g phosphoric acid was added and stirring was continued for 10min. Subsequently, low-boiling substances were removed at 160℃ and 5kPa for 30min to obtain carboxyl-enriched low molecular weight polyester affinity segments.

[0049] Step 2: Add 500g of nano zinc oxide, 4000g of anhydrous ethanol, 600g of deionized water, and 90g of 25% ammonia solution to a stirred glass or stainless steel reactor. Stir at 800r / min for 30min at 35℃. Separately, mix 60g of tetraethyl orthosilicate and 400g of anhydrous ethanol to form a dropping solution. Add this solution dropwise to the nano zinc oxide dispersion system over 40min. After the addition is complete, continue stirring at 800r / min for 180min at 35℃. After the reaction is complete, centrifuge at 8000r / min for 20min and discard the supernatant. Wash the precipitate successively with 3000g of anhydrous ethanol and 2000g of deionized water, centrifuge again at 8000r / min for 20min, collect the solid, dry the solid at 110℃ for 8h, and then heat-treat at 280℃ for 30min in a nitrogen atmosphere to obtain silicon-oxygen modified nano zinc oxide.

[0050] Step 3: Take 500g of the silicon-oxygen modified nano zinc oxide obtained in Step 2 and 125g of the carboxyl-enriched low molecular weight polyester affinity segments obtained in Step 1 and add them to a nitrogen-protected internal mixer. Mix them at 210℃ and 60r / min for 100min. After discharge, vacuum dry them at 120℃ and 5kPa for 6h, pulverize them and pass them through a 200-mesh sieve to obtain interface-oriented compatibility nano zinc oxide.

[0051] Step 4: Take 2200g of polyethylene terephthalate (PET) chips and vacuum dry them at 160℃ and below 100Pa for 8 hours. Add the dried PET chips to the main feed port of a co-rotating twin-screw extruder. Set the screw zone temperature to 255℃, zone 2 to 265℃, zone 3 to 270℃, zone 4 to 272℃, and the die head temperature to 270℃. Set the screw speed to 150r / min. After the PET chips have been stably melted and extruded, add 650g of the interface-oriented compatibility nano zinc oxide obtained in Step 3 from the first side feed port and mix for 7 minutes. Then add 85g of the hydroxyl-terminated low molecular weight PET oligomer obtained in Step 1 from the second side feed port and continue mixing for 5 minutes. After vacuum degassing, extrusion, cooling, and pelletizing, obtain the antibacterial and UV-resistant functional masterbatch.

[0052] Step 5: Take 1500g of the antibacterial and UV-resistant functional masterbatch obtained in Step 4 and 18500g of polyethylene terephthalate chips, and vacuum dry them at 160℃ and below 100Pa for 8 hours respectively. Then, mix and melt spin them in a melt spinning machine. The temperature of the first zone of the screw is set to 276℃, the temperature of the second zone is set to 282℃, the temperature of the third zone is set to 286℃, the temperature of the spinning box is set to 286℃, the output of the metering pump is set to 40g / min, the spinneret has 36 holes, the diameter of the spinneret hole is 250μm, the side blowing temperature is 22℃, the side blowing speed is 40cm / s, the oiling amount is 6g / kg, and the winding speed is 1200m / min. The resulting raw filament is preheated by a hot roller at 85℃ and then stretched by 330%, and then heat-set at 170℃ to obtain antibacterial and UV-resistant polyester filament.

[0053] Example 5:

[0054] Step 1: Add 1000g of bis(2-hydroxyethyl) terephthalate and 2g of tetrabutyl titanate to a reactor equipped with a stirrer, nitrogen purging, and vacuum interface. After purging with nitrogen three times, raise the temperature to 220℃ and stir at 120r / min for 60min. Then, reduce the pressure inside the reactor to 5kPa within 30min and react at 220℃ and 5kPa for 95min, collecting the distilled ethylene glycol. After the reaction, cool the melt to 180℃ and discharge it to obtain hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer. Weigh 300g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and seal it for subsequent use as a longer chain co-linking segment. Separately weigh 500g of hydroxyl-terminated low molecular weight ethylene glycol terephthalate oligomer and 115g of... 1,2,4-Benzotricarboxylic anhydride and 1g tetrabutyl titanate were added to a reaction vessel and stirred at 120r / min for 80min at 180℃ and under nitrogen protection. Then 2g phosphoric acid was added and stirring was continued for 10min. Subsequently, low-boiling substances were removed at 160℃ and 5kPa for 30min to obtain carboxyl-enriched low molecular weight polyester affinity segments.

[0055] Step 2: Add 500g of nano zinc oxide, 4000g of anhydrous ethanol, 600g of deionized water, and 90g of 25% ammonia solution to a stirred glass or stainless steel reactor. Stir at 800r / min for 30min at 35℃. Separately, mix 45g of tetraethyl orthosilicate and 400g of anhydrous ethanol to form a dropping solution. Add this solution dropwise to the nano zinc oxide dispersion system over 40min. After the addition is complete, continue stirring at 800r / min for 180min at 35℃. After the reaction is complete, centrifuge at 8000r / min for 20min and discard the supernatant. Wash the precipitate successively with 3000g of anhydrous ethanol and 2000g of deionized water, centrifuge again at 8000r / min for 20min, collect the solid, dry the solid at 110℃ for 8h, and then heat-treat at 280℃ for 30min in a nitrogen atmosphere to obtain silicon-oxygen modified nano zinc oxide.

[0056] Step 3: Take 500g of the silicon-oxygen modified nano zinc oxide obtained in Step 2 and 95g of the carboxyl-enriched low molecular weight polyester affinity segments obtained in Step 1 and add them to a nitrogen-protected internal mixer. Mix them at 205℃ and 60r / min for 85min. After discharge, vacuum dry them at 120℃ and 5kPa for 6h, pulverize them and pass them through a 200-mesh sieve to obtain interface-oriented compatibility nano zinc oxide.

[0057] Step 4: Take 2400g of polyethylene terephthalate (PET) chips and vacuum dry them at 160℃ and below 100Pa for 8 hours. Add the dried PET chips to the main feed port of a co-rotating twin-screw extruder. Set the screw zone temperature to 255℃, zone 2 to 265℃, zone 3 to 270℃, zone 4 to 272℃, and the die head temperature to 270℃. Set the screw speed to 150r / min. After the PET chips have been stably melted and extruded, add 500g of the interface-oriented compatibility nano zinc oxide obtained in Step 3 from the first side feed port and mix for 6 minutes. Then add 80g of the hydroxyl-terminated low molecular weight PET oligomer obtained in Step 1 from the second side feed port and continue mixing for 5 minutes. After vacuum degassing, extrusion, cooling, and pelletizing, obtain the antibacterial and UV-resistant functional masterbatch.

[0058] Step 5: Take 1400g of the antibacterial and UV-resistant functional masterbatch obtained in Step 4 and 18600g of polyethylene terephthalate chips, and vacuum dry them at 160℃ and below 100Pa for 8 hours respectively. Then, mix and melt spin them in a melt spinning machine. The temperature of the first zone of the screw is set to 276℃, the temperature of the second zone is set to 282℃, the temperature of the third zone is set to 286℃, the temperature of the spinning box is set to 286℃, the output of the metering pump is set to 40g / min, the spinneret has 36 holes, the diameter of the spinneret hole is 250μm, the side blowing temperature is 22℃, the side blowing speed is 40cm / s, the oiling amount is 6g / kg, and the winding speed is 1200m / min. The resulting raw filament is preheated by a hot roller at 85℃ and then stretched by 330%, and then heat-set at 170℃ to obtain antibacterial and UV-resistant polyester filament.

[0059] Comparative Example 1:

[0060] The difference from Example 1 is that: in step two, tetraethyl orthosilicate and 400g of anhydrous ethanol for preparing the dropping solution are not added. 500g of nano zinc oxide, 4000g of anhydrous ethanol, 600g of deionized water and 90g of ammonia water with a mass fraction of 25% are stirred at 35°C and 800r / min for 180min. Then, the mixture is treated under the same centrifugation, washing, drying and nitrogen heat treatment conditions as in step two of Example 1 to obtain nano zinc oxide without the formation of discontinuous silicon-oxygen nano islands. In step three, the nano zinc oxide without the formation of discontinuous silicon-oxygen nano islands is used instead of the silicon-oxygen modified nano zinc oxide obtained in step two of Example 1, and the other conditions are the same as in Example 1.

[0061] Comparative Example 2:

[0062] The difference from Example 1 is that in step two, the amount of tetraethyl orthosilicate is adjusted from 40g to 130g, and the amount of anhydrous ethanol used to prepare the dropping solution is still 400g. The remaining conditions for dispersion, dropping, reaction, centrifugation, washing, drying and nitrogen heat treatment are the same as in step two of Example 1, and high-silica-coated nano zinc oxide is obtained. In step three, this high-silica-coated nano zinc oxide is used instead of the silicon-modified nano zinc oxide obtained in step two of Example 1, and the remaining conditions are the same as in Example 1.

[0063] Comparative Example 3:

[0064] The difference from Example 1 is that in step three, instead of adding 90g of the carboxyl-enriched low molecular weight polyester affinity segments obtained in step one, 90g of the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer obtained in step one is added. The mixing, vacuum drying, pulverizing and sieving conditions are the same as in step three of Example 1, and the remaining conditions are the same as in Example 1.

[0065] Comparative Example 4:

[0066] The difference from Example 1 is that in step four, instead of delaying the addition of 60g of the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer obtained in step one at the second side feed port, the 60g of the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer is added at the same time as adding 500g of the interface-oriented compatibility nano zinc oxide obtained in step three at the first side feed port; the total mixing time after adding the material at the first side feed port is 10min, and the other conditions are the same as in Example 1.

[0067] Comparative Example 5:

[0068] The difference from Example 1 is that: in step four, 60g of the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer obtained in step one is not added, and the amount of polyethylene terephthalate chips used in step four is adjusted from 2400g to 2460g, so as to keep the total mass of material entering the extruder in step four unchanged; the other conditions are the same as in Example 1.

[0069] Comparative Example 6:

[0070] The difference from Example 1 is that 500g of the interface-oriented compatibility nano zinc oxide obtained in Step 3 is not added in Step 4, and the amount of polyethylene terephthalate chips used in Step 4 is adjusted from 2400g to 2900g to keep the total mass of material entering the extruder in Step 4 unchanged; the other conditions are the same as in Example 1.

[0071] Sample preparation before performance testing:

[0072] The antibacterial and UV-resistant polyester filaments obtained in Examples 1-5 and Comparative Examples 1-6 were used as fiber samples. Samples used for intrinsic fiber characterization, linear density, and tensile property testing were directly taken from the same batch of packaged filaments. Each sample was equilibrated for 24 hours in a standard atmosphere at 20°C and 65% relative humidity before testing. Fabric samples used for antibacterial and UV-resistant performance testing were prepared using the same knitting process: each filament was woven into a plain weave fabric on a 28-gauge single-sided circular knitting machine at a speed of 20 r / min, with a fabric weight controlled at 150 g / m². After finishing, the fabric was equilibrated for 24 hours in a standard atmosphere at 20°C and 65% relative humidity without dyeing, softening, antibacterial finishing, or UV-resistant finishing. Fabric samples used for wash resistance retesting were washed 20 times in a Type A washing machine according to the 4N program specified in GB / T 8629-2017, dried using a hanging drying program, and then equilibrated for 24 hours in a standard atmosphere at 20°C and 65% relative humidity before testing.

[0073] Tests on the content of silicon-oxygen nano-islands and the amount of organic grafting: The silicon-oxygen modified nano-zinc oxide obtained in step two of the examples, the interface-oriented compatible nano-zinc oxide obtained in step three, and the corresponding powders from the comparative example were subjected to thermogravimetric analysis according to GB / T 27761-2011 "Test Method for Weight Loss and Residual Amount of Thermogravimetric Analyzer". 8 mg of each sample was weighed and placed in an alumina crucible. The temperature was increased from 30℃ to 800℃ at a rate of 10℃ / min under nitrogen flow of 50 mL / min. Based on the residual mass of the blank nano-zinc oxide sample, the content of silicon-oxygen nano-islands in the silicon-oxygen modified nano-zinc oxide (calculated as silica) was calculated, and the amount of organic grafting in the interface-oriented compatible nano-zinc oxide within the 200-600℃ range was calculated.

[0074] Functional particle size distribution test: The interfacially oriented compatible nano-zinc oxide obtained in step three of the example and the corresponding powder obtained in step three of the comparative example were tested for particle size distribution according to GB / T 19077-2024 "Particle size analysis by laser diffraction". 0.20g of powder was weighed and added to 100mL of anhydrous ethanol, and ultrasonically dispersed at 200W for 10min, followed by immediate injection for testing; each sample was tested three times consecutively, and the average D90 value was taken as the evaluation index of the dispersion state of functional particles. The smaller the D90, the lower the degree of secondary agglomeration in the powder stage and before subsequent melt mixing, which is more conducive to reducing spinneret clogging and tensile stress defects.

[0075] Melt spinning stability test: The dried melt spinning raw materials used in the examples and comparative examples were taken and continuously spun for 8 hours according to the spinning conditions in step five of each example and comparative example. The pressure before and after filtration of the spinning assembly was recorded, and the pressure data was recorded every 30 minutes. The pressure before filtration at the beginning of spinning 30 minutes was taken as the initial pressure, and the pressure before filtration at the end of continuous spinning for 8 hours was taken as the termination pressure. The increase in filtration pressure was calculated. Each sample was spun three times, and the average value was taken as the melt spinning stability evaluation index.

[0076] Linear density and tensile properties testing of filaments: Filament samples obtained from the examples and comparative examples were used. First, the linear density was determined according to GB / T 14343-2008 "Test Method for Linear Density of Chemical Fiber Filaments," and then the breaking strength was determined according to GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments." Before the tensile test, the samples were equilibrated for 24 hours in standard atmosphere at 20℃ and 65% relative humidity. The clamping distance was set to 250 mm, and the tensile speed was set to 250 mm / min. Each sample was tested 20 times, and data where breakage occurred at the clamps were discarded. The average of the valid data was taken.

[0077] Antimicrobial performance test: Knitted fabric samples prepared according to the examples and comparative examples were tested for antimicrobial performance in accordance with GB / T 20944.3-2008 "Evaluation of antimicrobial properties of textiles - Part 3: Shaking method". The test bacteria were Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC 8739. For each sample, 0.75g of fabric was cut and placed in a 250mL Erlenmeyer flask, and 70mL of a 1×10⁻⁶ solution was added. 5 The bacterial suspension at CFU / mL was shaken at 24℃ and 150 rpm for 18 h. After shaking, serial dilutions, plate plating, and incubation were performed to count the bacteria and calculate the inhibition rates against Staphylococcus aureus and Escherichia coli. Three replicates were set up for each sample, and the average value was taken as the test result.

[0078] UV protection performance test: Knitted fabric samples prepared according to Examples 1 and Comparative Example 1 were tested for UV protection performance according to GB / T 18830-2009 "Evaluation of UV Protection Performance of Textiles". Before testing, the samples were equilibrated for 24 hours in standard atmosphere at 20℃ and 65% relative humidity. A UV transmittance meter with an integrating sphere was used, with a test wavelength range of 290nm-400nm and a wavelength interval of 5nm. Each sample was tested 5 times at different positions, and the average value was taken. The UV protection factor (UPF) and the average long-wave ultraviolet transmittance (T(UVA)AV) were recorded. The higher the UPF and the lower the T(UVA)AV, the more effective the UV absorption and scattering pathway of nano-zinc oxide in the fiber.

[0079] Functional retention test after washing: Knitted fabric samples prepared according to the examples and comparative examples were washed 20 times using the 4N program of a type A washing machine according to GB / T8629-2017 "Home washing and drying procedures for textile testing" and dried using the hanging drying program; after washing, the samples were equilibrated in a standard atmosphere at 20°C and 65% relative humidity for 24 hours, and the antibacterial properties were retested.

[0080] Table 1 Performance Test Results

[0081]

[0082] As shown in Table 1, Comparative Example 6, without the addition of interface-oriented compatibility nano-zinc oxide, had a filtration pressure increase of only 0.06 MPa during continuous spinning and a breaking strength of 3.82 cN / dtex. However, its antibacterial rates against Staphylococcus aureus and Escherichia coli were only 6.3% and 4.8%, respectively, with a UPF of only 17.8 and a T(UVA)AV of 10.86%. This indicates that ordinary polyester filaments do not possess effective antibacterial and UV protection functions.

[0083] Compared with Example 1, Comparative Example 1 did not form discontinuous silicon-oxygen nanoislands on the surface of nano zinc oxide. Although the exposed nano zinc oxide could still provide a certain initial antibacterial effect, its functional particle D90 increased to 1.24 μm, the filtration pressure increase value increased to 0.42 MPa, the breaking strength decreased to 3.20 cN / dtex, and the antibacterial rate of Staphylococcus aureus and Escherichia coli after washing decreased to 80.2% and 76.9%, respectively. This indicates that unpassivated nano zinc oxide is more likely to generate hard agglomeration and stretching defects in polyester melt.

[0084] Comparative Example 2 used excessive tetraethyl orthosilicate to form a high silica coating. Although the functional particle D90 was lower than that of Comparative Example 1, the inhibition rates of Staphylococcus aureus and Escherichia coli decreased to 90.6% and 86.8%, respectively, and the UPF decreased to 49.6. This indicates that an excessively thick or nearly continuous silica layer may reduce the effective contact and UV shielding efficiency of nano-zinc oxide.

[0085] Comparative Example 3 did not use carboxyl-enriched low molecular weight polyester affinity segments for interface anchoring. Its organic grafting amount decreased to 7.4%, the functional particle D90 increased to 1.09 μm, the filtration pressure increased to 0.38 MPa, and the E. coli inhibition rate decreased to 66.8% after washing. This indicates that simple hydroxyl-terminated oligomers are difficult to form a stable interface transition between functional particles and polyester matrix.

[0086] Comparative Examples 4 and 5 changed the timing of adding oligomers or removed the addition of oligomers, respectively. The powder D90 of both was the same as that of Example 1, but the filtration pressure increase was increased to 0.33 MPa and 0.29 MPa, respectively. The antibacterial rate and UPF after washing were lower than those of Example 1, indicating that the post-addition of hydroxyl-terminated low molecular weight polyethylene terephthalate oligomers has a promoting effect on melt compatibility, stretching stability and functional retention.

[0087] In Examples 1-5, with the synergistic adjustment of the content of silicon-oxygen nanoislands, the amount of carboxyl-enriched polyester affinity segments, and the amount of functional masterbatch added, the D90 of the functional particles was controlled at 0.51-0.72 μm, the filtration pressure rise was controlled at 0.13-0.27 MPa, and the tensile strength remained at 3.48-3.72 cN / dtex. Simultaneously, the antibacterial rates against Staphylococcus aureus and Escherichia coli, UPF, and T(UVA)AV reached 95.2%-99.4%, 92.8%-98.7%, 58.6-89.3%, and 1.21%-2.41%, respectively. Example 4, due to its higher amounts of functional particles and functional masterbatch, exhibited the highest antibacterial and UV protection properties, but its tensile strength was slightly lower than that of Examples 1-3. Example 5 demonstrated a good balance between high functional retention and good spinning stability.

[0088] In summary, this invention, through the combination of silicon-oxygen nano-islands, carboxyl-enriched low-molecular-weight polyester affinity segments, and the subsequent addition of hydroxyl-terminated low-molecular-weight polyethylene terephthalate oligomers, simultaneously improves the dispersion, interfacial bonding, and functional effects of nano-zinc oxide in polyester filaments, resulting in a synergistic enhancement of antibacterial, UV protection, washability, and spinnability.

[0089] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. An antibacterial and UV-resistant polyester fiber, comprising a polyethylene terephthalate matrix and interfacially oriented compatible nano-zinc oxide dispersed in the polyethylene terephthalate matrix, characterized in that, The raw materials for preparing the antibacterial and UV-resistant polyester fiber, by weight percentage, consist of 4.5%-7.5% antibacterial and UV-resistant functional masterbatch and the balance polyethylene terephthalate chips; The raw materials for preparing the antibacterial and UV-resistant functional masterbatch, by weight, consist of 2200-2600 parts of polyethylene terephthalate chips, 400-650 parts of interface-oriented compatible nano zinc oxide, and 45-85 parts of hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer. The antibacterial and UV-resistant functional masterbatch is prepared by first adding the interface-directed compatibility nano zinc oxide to the melted polyethylene terephthalate chips and then adding the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer and continuing to mix. The interface-oriented compatibility nano-zinc oxide is obtained by anchoring carboxyl-enriched low-molecular-weight polyester affinity segments onto the surface of silicon-oxygen modified nano-zinc oxide. The silicon-oxygen modified nano-zinc oxide is nano-zinc oxide with a surface containing 1.5%-4.0% silicon oxide compounds based on silicon dioxide. The carboxyl-enriched low-molecular-weight polyester affinity segments are obtained by reacting hydroxyl-terminated low-molecular-weight polyethylene terephthalate oligomers with 1,2,4-phenyltricarboxylic anhydride.

2. The antibacterial and UV-resistant polyester fiber according to claim 1, characterized in that, The silicon-oxygen content, calculated as silicon dioxide, is 1.8%-3.3%; the organic grafting amount of the interface-oriented compatible nano zinc oxide is 11.8%-18.1%.

3. The antibacterial and UV-resistant polyester fiber according to claim 1, characterized in that, The intrinsic viscosity of the polyethylene terephthalate chips is 0.6-0.7 dL / g; the average particle size of the nano zinc oxide is 15-25 nm.

4. The antibacterial and UV-resistant polyester fiber according to claim 1, characterized in that, The hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer was prepared by the following method: 1000 parts of bis(2-hydroxyethyl) terephthalate and 1.5-2.5 parts of tetrabutyl titanate were taken, heated to 215-230℃ under nitrogen protection and stirred for 50-70 min; then the pressure was reduced to 5 kPa within 30 min, and the reaction was carried out at 215-230℃ and 5 kPa for 70-110 min. After the reaction was completed, the melt was cooled to 180℃ and discharged to obtain the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer.

5. The antibacterial and UV-resistant polyester fiber according to claim 1, characterized in that, The carboxyl-enriched low molecular weight polyester affinity segment was prepared by the following method: 500 parts of hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer, 95-140 parts of 1,2,4-benzenetricarboxylic anhydride and 1 part of tetrabutyl titanate were taken and stirred at 178-182℃ under nitrogen protection for 70-90 min. Then, 2 parts of phosphoric acid were added and stirring was continued for 10 min. Subsequently, low-boiling substances were removed at 160℃ and 5 kPa for 30 min to obtain the carboxyl-enriched low molecular weight polyester affinity segment.

6. The antibacterial and UV-resistant polyester fiber according to claim 1, characterized in that, The silicon-oxygen modified nano zinc oxide was prepared by the following method: 500 parts of nano zinc oxide, 4000 parts of anhydrous ethanol, 600 parts of deionized water and 90 parts of ammonia water with a mass fraction of 25% were taken and stirred at 35°C for 30 min; 31-60 parts of tetraethyl orthosilicate and 400 parts of anhydrous ethanol were mixed to form a dropping solution, which was added dropwise to the nano zinc oxide dispersion system over 40 min. After the addition was completed, stirring was continued at 35°C for 180 min; after the reaction was completed, the supernatant was discarded by centrifugation, and the precipitate was washed with anhydrous ethanol and deionized water in sequence. After centrifugation again, the solid was collected, dried at 110°C for 8 h, and then heat-treated at 280°C for 30 min in a nitrogen atmosphere to obtain the silicon-oxygen modified nano zinc oxide.

7. The antibacterial and UV-resistant polyester fiber according to claim 1, characterized in that, The interface-oriented compatibility nano-zinc oxide was prepared by the following method: 500 parts of silicon-oxygen modified nano-zinc oxide and 70-125 parts of carboxyl-enriched low molecular weight polyester affinity segments were added to a nitrogen-protected internal mixer and mixed at 195-210℃ for 70-100 min; after discharge, the mixture was vacuum dried, pulverized and passed through a 200-mesh sieve to obtain the interface-oriented compatibility nano-zinc oxide.

8. The antibacterial and UV-resistant polyester fiber according to claim 1, characterized in that, The antibacterial and UV-resistant functional masterbatch is prepared by the following method: 2200-2600 parts of polyethylene terephthalate (PET) chips are dried under vacuum at 160℃ and below 100Pa for 8 hours; the dried PET chips are added to the main feed port of a co-rotating twin-screw extruder for melt extrusion; 400-650 parts of interface-oriented compatible nano-zinc oxide are added from the first side feed port and mixed for 5-7 minutes; then 45-85 parts of hydroxyl-terminated low molecular weight PET oligomer are added from the second side feed port and mixed for another 4-5 minutes; subsequently, the mixture is vacuum degassed, extruded, cooled, and pelletized to obtain the antibacterial and UV-resistant functional masterbatch.

9. A method for preparing antibacterial and UV-resistant polyester fiber by melt spinning according to any one of claims 1-8, characterized in that, Includes the following steps: (1) Prepare hydroxyl-terminated low molecular weight polyethylene terephthalate oligomers, and react a portion of the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomers with 1,2,4-benzenetricarboxylic anhydride to obtain carboxyl-enriched low molecular weight polyester affinity segments. (2) A silicon oxide compound is formed on the surface of nano zinc oxide to obtain silicon oxide modified nano zinc oxide; (3) The silicon-oxygen modified nano zinc oxide is mixed with the carboxyl-enriched low molecular weight polyester affinity segments, so that the carboxyl-enriched low molecular weight polyester affinity segments are anchored on the surface of the silicon-oxygen modified nano zinc oxide to obtain interface-oriented compatibility nano zinc oxide. (4) After melting polyethylene terephthalate chips, first add the interface-oriented compatibility nano zinc oxide and mix, then add the hydroxyl-terminated low molecular weight polyethylene terephthalate oligomer and continue mixing to obtain antibacterial and UV-resistant functional masterbatch. (5) The antibacterial and UV-resistant functional masterbatch is mixed with polyethylene terephthalate chips and melt-spun to obtain antibacterial and UV-resistant polyester fiber.

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