A method for preparing an antibacterial regenerated polyester staple

Abstract

This invention discloses a method for preparing antibacterial recycled polyester staple fiber. The method uses hexagonal boron nitride, dopamine, copper, terephthalic acid, and ethylene glycol as main components. Through ball milling, ultrasonication, and calcination, an antibacterial polyester masterbatch is obtained. The antibacterial masterbatch is then mixed with recycled polyester raw materials, dried, and melt-blended and spun to obtain antibacterial recycled polyester staple fiber. The fiber bundle is then cut and packaged to obtain the finished product. The advantages of this invention are that it simultaneously incorporates copper, hexagonal boron nitride, and carbon materials with antibacterial properties into the preparation process of antibacterial recycled polyester staple fiber. The preparation method is simple, and the antibacterial performance is excellent. It also exhibits good flame retardant properties, electrical conductivity, and mechanical properties, greatly expanding the application fields of polyester staple fiber. Furthermore, using recycled polyester as raw material can reduce the amount of waste polyester in nature, which not only reduces environmental pollution but also alleviates the problem of scarce petroleum resources.

Description

Technical Field

[0001] This invention relates to a method for preparing recycled polyester staple fiber, and particularly to a method for preparing antibacterial recycled polyester staple fiber, belonging to the field of polyester fiber manufacturing technology. Background Technology

[0002] Polyethylene terephthalate (PET) is a semi-crystalline thermoplastic polyester with excellent chemical and physical properties. It is widely used in textiles, packaging bottles, electronic devices, and machinery manufacturing, and is currently the most widely used polyester material worldwide. Due to PET's excellent stability, it is difficult to biodegrade naturally in the environment, causing serious environmental pollution. Therefore, it is necessary to recycle and reuse PET to reduce the amount of waste polyester in the cycle and mitigate environmental pollution.

[0003] Polyester fiber is widely used in clothing, home textiles, and decoration due to its advantages such as high strength, good elasticity, heat resistance, light resistance, and acid and alkali resistance. It also has good processability and easy spinning properties. Its fabrics are washable, wear-resistant, wrinkle-resistant, and require no ironing. It occupies a huge market share and is one of the most important applications of PET.

[0004] With social development and increasing demands in human life, traditional polyester fibers, due to their poor antibacterial, conductive, and flame-retardant properties, no longer meet the needs of human production and daily life. Patent application number CN202011428377.9 discloses a method for manufacturing antibacterial polyester staple fibers: polyester resin is mixed with antibacterial masterbatch after impurity removal, slicing, dehumidification, and drying; the mixture is then heated and melted to obtain a polyester fiber spinning melt. This melt is then subjected to spinning, winding, stretching, and heat setting processes to obtain antibacterial polyester staple fibers. This method simplifies the production process, and the produced polyester staple fibers exhibit good antibacterial properties. Patent application CN201811002692.8 discloses a composite antibacterial polyester staple fiber and its preparation method: using disodium propylenediaminetetraacetate as a chelating agent, copper, zinc, and calcium ions are gradually chelated and coated to form a composite antibacterial agent. A composite antibacterial polyester masterbatch is then prepared by melt blending. This masterbatch is further thickened by liquid phase to obtain a composite antibacterial polyester masterbatch. The composite antibacterial polyester masterbatch is then melt-blended and spun with recycled polyester chips to obtain composite antibacterial polyester staple fibers with good antibacterial ability. Patent application CN201310742904.7 discloses an anti-mite and antibacterial polyester staple fiber and its preparation method: anti-mite and antibacterial polyester staple fibers are prepared by esterification polymerization spinning of micron-sized heat-storing anti-mite ceramic powder and silver-loaded nano-titanium dioxide composite antibacterial powder. The resulting anti-mite and antibacterial polyester staple fibers exhibit strong antibacterial effects against Staphylococcus aureus and Escherichia coli. Patent application CN201911168948.7 discloses a preparation process for antibacterial virgin polyester staple fiber: Antibacterial masterbatch preparation: An antibacterial masterbatch is prepared using dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, arachidonic acid propionate, dimethyl terephthalate, propylene glycol, and a dispersant as raw materials. The antibacterial virgin polyester staple fiber is then obtained through raw material processing, heating and melting, spinning, cooling and forming, oiling, winding and bundling, and crimping and cutting processes. The produced polyester staple fiber exhibits good antibacterial properties. However, the above-mentioned preparation process for polyester staple fiber involves relatively simple improvements to fiber properties, and the large amount of antibacterial agent used reduces the mechanical and thermal properties of the polyester fiber. Therefore, it is necessary to develop a novel polyester staple fiber that integrates antibacterial, conductive, and flame-retardant properties. This would improve the antibacterial properties of polyester staple fiber while also enhancing its flame retardancy and conductivity, thus expanding the application market for polyester staple fiber.

[0005] Copper, due to its excellent antibacterial properties, is widely used in antibacterial fibers, medicine, and drinking water disinfection. As an antibacterial agent, copper can effectively control the biological activity of common bacteria such as Gram-negative bacilli, Gram-positive cocci, and Candida. Furthermore, studies have shown that some carbon materials also possess antibacterial functions, such as graphene and carbon nanotubes. After calcination, dopamine loses its amino and hydroxyl functional groups, forming a carbon layer uniformly coating the surface of a boron nitride matrix, exhibiting certain antibacterial properties. Because hexagonal boron nitride has a layered structure similar to graphite, it is also known as "white graphene." Research has found that "white graphene" also possesses good antibacterial properties and has great potential for development in fiber applications. As a novel two-dimensional material, boron nitride has a large surface area and a typical layered structure. It can serve as a physical barrier layer in the combustion process of polymer materials and as a good barrier to slow down heat transfer and effectively transfer combustible gases, greatly improving the flame retardant properties of polymer materials. However, there is currently no research on the use of boron nitride, carbon, and copper composites to manufacture antibacterial recycled polyester staple fibers. Summary of the Invention

[0006] To address the shortcomings of abundant waste polyester reserves in nature and the poor antibacterial effect of traditional polyester staple fibers, this invention provides a method for preparing antibacterial recycled polyester staple fibers. An antibacterial polyester masterbatch is prepared using boron nitride, carbon materials, and copper as the main antibacterial components. The antibacterial masterbatch is then mixed with recycled polyester raw materials, dried, and melt-blended and spun. The resulting recycled polyester staple fibers exhibit excellent antibacterial properties, along with good flame retardant, electrical conductivity, and mechanical properties, significantly expanding the application areas of polyester staple fibers. Furthermore, using recycled polyester as a raw material reduces the amount of waste polyester reserves in nature, which not only avoids environmental pollution but also alleviates the problem of scarce petroleum resources.

[0007] A method for preparing antibacterial recycled polyester staple fiber, the specific steps of which are as follows:

[0008] (1) Preparation of antibacterial masterbatch: Hexagonal boron nitride and dopamine are wet-milled to load dopamine onto the boron nitride matrix. The milled product is then placed in a copper salt solution for adsorption. The oxygen atoms on the catechol in dopamine complex with metal ions through shared electrons, and the metallic copper is uniformly dispersed onto the boron nitride-loaded dopamine precursor. After calcination in a tube furnace, dopamine loses hydroxyl and amino groups, forming a carbon layer that coats the boron nitride matrix, forming a composite of boron nitride, copper, and carbon material, BN@C@Cu. The calcined product and dispersant are then ultrasonically dispersed in an ethylene glycol solution. A catalyst is then added to the reaction system of ethylene glycol dispersion and terephthalic acid to prepare polyester through esterification and polycondensation reactions. The polyester is then extruded, granulated, and dried to obtain the polyester antibacterial masterbatch.

[0009] (2) Spinning process: The antibacterial masterbatch and recycled polyester raw materials are weighed according to a certain mass ratio, mixed and dried, and then processed through spinning, ring blowing, oiling, bundling, stretching, crimping, relaxation heat setting, cutting and packaging to obtain antibacterial recycled polyester short fibers.

[0010] Preferably, the mass ratio of boron nitride to dopamine in step (1) is 1:0.1-10, the ball mill is a planetary ball mill, and the ball milling conditions are: ball mill speed 400 rpm, forward and reverse rotation for 5 min, and interval time 30 s.

[0011] Preferably, the copper salt solution in step (1) is one of copper chloride solution, copper nitrate solution, or copper sulfate solution, and the concentration of the copper salt solution is 100-800 mg / L.

[0012] Preferably, the calcination temperature in step (1) is 800-1200℃ and the holding time is 2-4h.

[0013] Preferably, the dispersant in step (1) includes: white oil, zinc stearate, polyethylene wax, stearic acid, paraffin wax, ethylene bis-stearamide, etc.

[0014] Preferably, the mass concentration of the BN@C@Cu complex in the diol in step (1) is 10%-20%.

[0015] Preferably, the catalyst in step (1) is one of zinc acetate, cobalt acetate, or manganese acetate, and the amount of catalyst used is 0.001-0.06 wt% of the mass of terephthalic acid; the molar ratio of terephthalic acid to diol is 1:1.1-1.6.

[0016] Preferably, the esterification reaction temperature in step (1) is 220-260℃, the esterification pressure is 0.1MPa-0.4MPa, the polycondensation reaction temperature is 250-290℃, the polycondensation pressure is a vacuum degree ≤100Pa, and the intrinsic viscosity of the polyester is 0.1-0.5dL / g.

[0017] Preferably, the extrusion granulation in step (1) is divided into six zones, and the screw temperatures of the six zones are as follows: Zone 1 220-250℃, Zone 2 230-260℃, Zone 3 250-280℃, Zone 4 260-290℃, Zone 5 260-290℃, and Zone 6 260-290℃.

[0018] As a preferred embodiment, the method for preparing an antibacterial recycled polyester staple fiber described in step (2) is characterized in that the recycled polyester raw material is selected from one or two of the following: fabric foam processed from waste polyester textiles and recycled polyester bottle flakes.

[0019] As a preferred embodiment, the method for preparing an antibacterial recycled polyester staple fiber described in step (2) is characterized in that the mass fractions of the antibacterial masterbatch and the recycled polyester raw material are respectively: 1-4 parts of antibacterial masterbatch and 96-99 parts of recycled polyester.

[0020] As a preferred embodiment, the method for preparing an antibacterial recycled polyester staple fiber described in step (2) is characterized in that the mixed drying conditions are as follows: drying is carried out using a vacuum drum dryer with a vacuum degree lower than -0.09MPa, a rotation speed of 4r / min, a drying temperature of 110-150℃, and a drying time of 8-12h.

[0021] As a preferred embodiment, the method for preparing an antibacterial recycled polyester staple fiber described in step (2) is characterized in that the spinning temperature is 270-285℃, and the temperature fluctuation is controlled within ±2℃; the cooling wind speed of the ring blower is 0.5-4.0m / s, the relative humidity is controlled within 65%-80%, the wind temperature is controlled within 20-30℃, and the oiling rate is controlled within 0.1%-0.2%.

[0022] As a preferred embodiment, the method for preparing an antibacterial recycled polyester staple fiber described in step (2) is characterized in that the width of the crimping wheel in the bundling process is (4.4-6.6)×103dtex / mm, and the variation of the bus density of the bundled fiber is controlled within ±4%.

[0023] As a preferred embodiment, the method for preparing an antibacterial recycled polyester staple fiber described in step (2) is characterized in that the stretching process adopts two stretching steps. The first stretching is carried out in a hot oil-water bath with the temperature controlled at 60-80℃. The second stretching uses superheated steam (steam pressure greater than 0.1MPa) at 130-150℃ to heat the filament bundle to 100-120℃.

[0024] As a preferred embodiment, the method for preparing an antibacterial recycled polyester staple fiber described in step (2) is characterized in that the relaxation heat setting process adopts a chain plate relaxation heat setting machine, the drying zone temperature is 110-120℃, the heat setting zone temperature is 120-130℃, and the drying heat setting time is controlled at 15-20min.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0026] (1) The preparation process of antibacterial recycled polyester staple fiber is simple and has excellent antibacterial properties by simultaneously applying copper, hexagonal boron nitride and carbon materials with antibacterial properties.

[0027] (2) In addition to antibacterial properties, the antibacterial components have good flame retardant properties, electrical conductivity and mechanical properties, which greatly expands the application field of polyester staple fiber. Detailed Implementation

[0028] The present invention will be further illustrated below with specific examples. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0029] Example 1:

[0030] 1. Preparation of antibacterial masterbatch: Dopamine was loaded onto boron nitride by wet ball milling at a mass ratio of 1:1 with boron nitride. The product was then placed in a 100 mg / L copper nitrate solution for 3 h for adsorption, where copper ions were adsorbed onto the boron nitride-loaded dopamine precursor. The product was then placed in a tube furnace and calcined at 900 °C for 2 h under a nitrogen atmosphere at a heating rate of 5 °C / min to obtain a composite material BN@C@Cu of boron nitride, copper, and carbon. The BN@C@Cu composite and a dispersant were then uniformly dispersed in an ethylene glycol solution at a high speed of 3000 r / min, with the total mass of the BN@C@Cu composite and the dispersant accounting for 10% of the mass of the ethylene glycol solution. A uniform dispersion was prepared. Polyester was prepared by adding a catalyst to an esterification reaction and a polycondensation reaction using ethylene glycol dispersion and terephthalic acid as monomers. The catalyst was zinc acetate, and the amount of catalyst was 0.006 wt% of the mass of terephthalic acid. The molar ratio of terephthalic acid to ethylene glycol was 1:1.3. The esterification reaction temperature was 240℃, and the esterification pressure was 0.1 MPa. The polycondensation reaction was carried out at a temperature of 260℃ and a pressure of vacuum 80 Pa. The intrinsic viscosity of the polyester was 0.3 dL / g. The obtained polyester was extruded, granulated, and dried. The extrusion screw temperatures were: zone 1 220℃, zone 2 230℃, zone 3 250℃, zone 4 260℃, zone 5 260℃, and zone 6 260℃.

[0031] 2. Spinning process parameters: The recycled polyester raw material is fabric foam processed from waste polyester textiles. The mass fractions of antibacterial masterbatch and recycled polyester raw material are 5 parts antibacterial masterbatch and 95 parts recycled polyester. The vacuum drum dryer has a vacuum degree of -0.1MPa, a rotation speed of 4r / min, a drying temperature of 120℃, and a drying time of 8h. The spinning temperature is 275℃±2℃. The ring blowing cooling air velocity is 3.0m / s, the relative humidity is 75%, and the air temperature is 25℃. The oiling rate is 0.1%. The first stretching temperature is 80℃, and the second stretching temperature is 135℃. Superheated steam heats the fiber bundle to 105℃. In the bundling process, the crimping wheel width is 5×103dtex / mm, and the bus density variation of the bundled fibers is controlled within ±4%. The relaxation heat setting process uses a chain plate relaxation heat setting machine. The drying zone temperature is 110℃, and the heat setting zone temperature is 120℃. The drying heat setting time is 15min.

[0032] Example 2:

[0033] 1. Preparation of antibacterial masterbatch: Dopamine was loaded onto boron nitride by wet ball milling at a mass ratio of 2:1 with boron nitride. The product was then placed in a 200 mg / L copper nitrate solution for 2 h for adsorption, where copper ions were adsorbed onto the boron nitride-loaded dopamine precursor. The product was then placed in a tube furnace and calcined at 900 °C for 3 h under a nitrogen atmosphere at a heating rate of 5 °C / min to obtain a composite material BN@C@Cu of boron nitride, copper, and carbon. The BN@C@Cu composite and a dispersant were then uniformly dispersed in an ethylene glycol solution at a high speed of 3500 r / min, with the total mass of the BN@C@Cu composite and the dispersant accounting for 15% of the mass of the ethylene glycol solution. A uniform dispersion was prepared. Polyester was prepared by adding a catalyst to an ethylene glycol dispersion and terephthalic acid as monomers through esterification and polycondensation reactions. The catalyst was manganese acetate, and the amount of catalyst was 0.005 wt% of the mass of terephthalic acid. The molar ratio of terephthalic acid to ethylene glycol was 1:1.1. The esterification reaction temperature was 220℃, and the esterification pressure was 0.2 MPa. The polycondensation reaction was carried out at a temperature of 265℃ and a pressure of 90 Pa under vacuum. The intrinsic viscosity of the polyester was 0.2 dL / g. The obtained polyester was then extruded, granulated, and dried. The extrusion screw temperatures were: Zone 1 230℃, Zone 2 240℃, Zone 3 260℃, Zone 4 270℃, Zone 5 270℃, and Zone 6 270℃.

[0034] 2. Spinning process parameters: The recycled polyester raw material is fabric foam processed from waste polyester textiles. The mass fractions of antibacterial masterbatch and recycled polyester raw material are 4 parts antibacterial masterbatch and 96 parts recycled polyester. The vacuum drum dryer has a vacuum degree of -0.15MPa, a rotation speed of 4r / min, a drying temperature of 110℃, and a drying time of 10h. The spinning temperature is 270℃±2℃. The ring blowing cooling air velocity is 3.5m / s, the relative humidity is 70%, and the air temperature is 26℃. The oiling rate is 0.15%. The first stretching temperature is 70℃, and the second stretching temperature is 130℃. Superheated steam heats the fiber bundle to 110℃. In the bundling process, the crimping wheel width is 4.5×103dtex / mm, and the overall fiber density variation is controlled within ±4%. The relaxation heat setting process uses a chain plate relaxation heat setting machine. The drying zone temperature is 115℃, and the heat setting zone temperature is 125℃. The drying and heat setting time is 20min.

[0035] Example 3:

[0036] 1. Preparation of antibacterial masterbatch: Dopamine was loaded onto boron nitride by wet ball milling at a mass ratio of 1:2 with boron nitride. The product was then placed in a 100 mg / L copper nitrate solution for 3 h for adsorption, where copper ions were adsorbed onto the boron nitride-loaded dopamine precursor. The product was then placed in a tube furnace and calcined at 900 °C for 2 h under a nitrogen atmosphere at a heating rate of 5 °C / min to obtain a composite material BN@C@Cu of boron nitride, copper, and carbon. The BN@C@Cu composite and a dispersant were then uniformly dispersed in an ethylene glycol solution at a high speed of 3000 r / min, with the total mass of the BN@C@Cu composite and the dispersant accounting for 10% of the mass of the ethylene glycol solution. A uniform dispersion was prepared. Polyester was prepared by adding a catalyst to an ethylene glycol dispersion and terephthalic acid as monomers through esterification and polycondensation reactions. The catalyst was cobalt acetate, and the amount of catalyst was 0.006 wt% of the mass of terephthalic acid. The molar ratio of terephthalic acid to ethylene glycol was 1:1.3. The esterification reaction temperature was 240℃, and the esterification pressure was 0.1 MPa. The polycondensation reaction was carried out at a temperature of 260℃ and a pressure of 80 Pa under vacuum. The intrinsic viscosity of the polyester was 0.3 dL / g. The obtained polyester was then extruded, granulated, and dried. The extrusion screw temperatures were: Zone 1 220℃, Zone 2 230℃, Zone 3 250℃, Zone 4 260℃, Zone 5 260℃, and Zone 6 260℃.

[0037] 2. Spinning process parameters: The recycled polyester raw material is recycled polyester bottle flakes. The mass fractions of antibacterial masterbatch and recycled polyester raw material are 5 parts antibacterial masterbatch and 95 parts recycled polyester, respectively. The vacuum drum dryer has a vacuum degree of -0.1MPa, a rotation speed of 4r / min, a drying temperature of 120℃, and a drying time of 8h. The spinning temperature is 275℃±2℃. The ring blowing cooling air velocity is 3.0m / s, the relative humidity is 75%, and the air temperature is 25℃. The oiling rate is 0.1%. The first stretching temperature is 80℃, and the second stretching temperature is 135℃. Superheated steam heats the fiber bundle to 105℃. In the bundling process, the crimping wheel width is 5×103dtex / mm, and the bus density variation of the bundled fibers is controlled within ±4%. The relaxation heat setting process uses a chain plate relaxation heat setting machine. The drying zone temperature is 110℃, and the heat setting zone temperature is 120℃. The drying heat setting time is 15min.

[0038] Example 4:

[0039] 1. Preparation of antibacterial masterbatch: Dopamine was loaded onto boron nitride by wet ball milling at a mass ratio of 4:1 with boron nitride. The product was then placed in a 200 mg / L copper nitrate solution for 2 h for adsorption, where copper ions were adsorbed onto the boron nitride-loaded dopamine precursor. The product was then placed in a tube furnace and calcined at 900 °C for 3 h under a nitrogen atmosphere at a heating rate of 5 °C / min to obtain a composite material BN@C@Cu of boron nitride, copper, and carbon. The BN@C@Cu composite and a dispersant were then uniformly dispersed in an ethylene glycol solution at a high speed of 3500 r / min, with the total mass of the BN@C@Cu composite and the dispersant accounting for 15% of the mass of the ethylene glycol solution. A uniform dispersion was prepared. Polyester was prepared by adding a catalyst to an ethylene glycol dispersion and terephthalic acid as monomers through esterification and polycondensation reactions. The catalyst was manganese acetate, and the amount of catalyst was 0.005 wt% of the mass of terephthalic acid. The molar ratio of terephthalic acid to ethylene glycol was 1:1.1. The esterification reaction temperature was 220℃, and the esterification pressure was 0.2 MPa. The polycondensation reaction was carried out at a temperature of 265℃ and a pressure of 90 Pa under vacuum. The intrinsic viscosity of the polyester was 0.2 dL / g. The obtained polyester was then extruded, granulated, and dried. The extrusion screw temperatures were: Zone 1 230℃, Zone 2 240℃, Zone 3 260℃, Zone 4 270℃, Zone 5 270℃, and Zone 6 270℃.

[0040] 2. Spinning process parameters: The recycled polyester raw material is recycled polyester bottle flakes. The mass fractions of antibacterial masterbatch and recycled polyester raw material are 4 parts antibacterial masterbatch and 96 parts recycled polyester, respectively. The vacuum drum dryer has a vacuum degree of -0.15MPa, a rotation speed of 4r / min, a drying temperature of 110℃, and a drying time of 10h. The spinning temperature is 270℃±2℃. The ring blowing cooling air velocity is 3.5m / s, the relative humidity is 70%, and the air temperature is 26℃. The oiling rate is 0.15%. The first stretching temperature is 70℃, and the second stretching temperature is 130℃. Superheated steam heats the fiber bundle to 110℃. In the bundling process, the crimping wheel width is 4.5×103dtex / mm, and the overall fiber density variation is controlled within ±4%. The relaxation heat setting process uses a chain plate relaxation heat setting machine. The drying zone temperature is 115℃, and the heat setting zone temperature is 125℃. The drying and heat setting time is 20min.

[0041] Example 5:

[0042] 1. Preparation of antibacterial masterbatch: Dopamine was loaded onto boron nitride by wet ball milling at a mass ratio of 1:4 with boron nitride. The product was then placed in a 200 mg / L copper nitrate solution for 2 h for adsorption, where copper ions were adsorbed onto the boron nitride-loaded dopamine precursor. The product was then placed in a tube furnace and calcined at 900 °C for 3 h under a nitrogen atmosphere at a heating rate of 5 °C / min to obtain a composite material BN@C@Cu of boron nitride, copper, and carbon. The BN@C@Cu composite and a dispersant were then uniformly dispersed in an ethylene glycol solution at a high speed of 3500 r / min, with the total mass of the BN@C@Cu composite and the dispersant accounting for 15% of the mass of the ethylene glycol solution. A uniform dispersion was prepared. Polyester was prepared by adding a catalyst to an esterification reaction and a polycondensation reaction using ethylene glycol dispersion and terephthalic acid as monomers. The catalyst was zinc acetate, and the amount of catalyst was 0.005 wt% of the mass of terephthalic acid. The molar ratio of terephthalic acid to ethylene glycol was 1:1.1. The esterification reaction temperature was 220℃, and the esterification pressure was 0.2 MPa. The polycondensation reaction was carried out at a temperature of 265℃ and a pressure of vacuum of 90 Pa. The intrinsic viscosity of the polyester was 0.2 dL / g. The obtained polyester was extruded, granulated, and dried. The extrusion screw temperatures were: zone 1 230℃, zone 2 240℃, zone 3 260℃, zone 4 270℃, zone 5 270℃, and zone 6 270℃.

[0043] 2. Spinning process parameters: The recycled polyester raw material is recycled polyester bottle flakes. The mass fractions of antibacterial masterbatch and recycled polyester raw material are 4 parts antibacterial masterbatch and 95 parts recycled polyester, respectively. The vacuum drum dryer has a vacuum degree of -0.15MPa, a rotation speed of 4r / min, a drying temperature of 110℃, and a drying time of 10h. The spinning temperature is 270℃±2℃. The ring blowing cooling air velocity is 3.5m / s, the relative humidity is 70%, and the air temperature is 26℃. The oiling rate is 0.15%. The first stretching temperature is 70℃, and the second stretching temperature is 130℃. Superheated steam heats the fiber bundle to 110℃. In the bundling process, the crimping wheel width is 4.5×103dtex / mm, and the overall fiber density variation is controlled within ±4%. The relaxation heat setting process uses a chain plate relaxation heat setting machine. The drying zone temperature is 115℃, and the heat setting zone temperature is 125℃. The drying and heat setting time is 20min.

[0044] Comparative Example 1:

[0045] 1. Preparation of antibacterial masterbatch: Boron nitride and copper sulfate powder were mixed at a mass ratio of 1:1 and ball-milled to obtain a copper-doped boron nitride precursor. The product was then placed in a tube furnace and calcined at 900°C for 2 hours under a nitrogen atmosphere at a heating rate of 5°C / min to obtain copper-doped boron nitride (BN@Cu). The BN@Cu composite and dispersant were uniformly dispersed in an ethylene glycol solution at a high speed of 3000 r / min, with the total mass of the BN@Cu composite and dispersant accounting for 10% of the mass of the ethylene glycol solution, to form a uniform dispersion. A catalyst was added using the ethylene glycol dispersion and terephthalic acid as monomers. Polyester was prepared by esterification and polycondensation reactions. The catalyst was zinc acetate, and the catalyst dosage was 0.006 wt% of terephthalic acid. The molar ratio of terephthalic acid to ethylene glycol was 1:1.3. The esterification reaction temperature was 220℃, and the esterification pressure was 0.1 MPa. The polycondensation reaction was carried out at 260℃ and the polycondensation pressure was a vacuum of 80 Pa. The intrinsic viscosity of the polyester was 0.3 dL / g. The obtained polyester was then extruded, granulated, and dried. The extrusion screw temperatures were: zone 1 220℃, zone 2 230℃, zone 3 250℃, zone 4 260℃, zone 5 260℃, and zone 6 260℃.

[0046] 2. Spinning process parameters: The recycled polyester raw material is recycled polyester bottle flakes. The mass fractions of antibacterial masterbatch and recycled polyester raw material are 4 parts antibacterial masterbatch and 95 parts recycled polyester, respectively. The vacuum drum dryer has a vacuum degree of -0.15MPa, a rotation speed of 4r / min, a drying temperature of 110℃, and a drying time of 10h. The spinning temperature is 270℃±2℃. The ring blowing cooling air velocity is 3.5m / s, the relative humidity is 70%, and the air temperature is 26℃. The oiling rate is 0.15%. The first stretching temperature is 70℃, and the second stretching temperature is 130℃. Superheated steam heats the fiber bundle to 110℃. In the bundling process, the crimping wheel width is 4.5×103dtex / mm, and the overall fiber density variation is controlled within ±4%. The relaxation heat setting process uses a chain plate relaxation heat setting machine. The drying zone temperature is 115℃, and the heat setting zone temperature is 125℃. The drying and heat setting time is 20min.

[0047] Comparative Example 2:

[0048] 1. Preparation of antibacterial masterbatch: Dopamine was loaded onto boron nitride by wet ball milling at a mass ratio of 1:1 with boron nitride. The product was then calcined in a tube furnace under nitrogen atmosphere at a heating rate of 5°C / min to 900°C for 2 hours to obtain a boron nitride-carbon composite BN@C. The BN@C composite and a dispersant were uniformly dispersed in an ethylene glycol solution at a high speed of 3000 r / min, with the total mass of the BN@C composite and the dispersant accounting for 10% of the mass of the ethylene glycol solution, to form a uniform dispersion. Using the ethylene glycol dispersion and terephthalic acid as monomers, a catalyst was added to esterify the product. Polyester was prepared by esterification and polycondensation reactions. The catalyst was zinc acetate, and the catalyst dosage was 0.006 wt% of the mass of terephthalic acid. The molar ratio of terephthalic acid to ethylene glycol was 1:1.3. The esterification reaction temperature was 220℃, and the esterification pressure was 0.1 MPa. Polycondensation reaction was carried out at 260℃ and the polycondensation pressure was a vacuum of 80 Pa. The intrinsic viscosity of the polyester was 0.3 dL / g. The obtained polyester was then extruded, granulated, and dried. The extrusion screw temperatures were: zone 1 220℃, zone 2 230℃, zone 3 250℃, zone 4 260℃, zone 5 260℃, and zone 6 260℃.

[0049] 2. Spinning process parameters: The recycled polyester raw material is fabric foam processed from waste polyester textiles. The mass fractions of antibacterial masterbatch and recycled polyester raw material are 4 parts antibacterial masterbatch and 96 parts recycled polyester. The vacuum drum dryer has a vacuum degree of -0.1MPa, a rotation speed of 4r / min, a drying temperature of 120℃, and a drying time of 8h. The spinning temperature is 275℃±2℃. The ring blowing cooling air velocity is 3.0m / s, the relative humidity is 75%, and the air temperature is 25℃. The oiling rate is 0.1%. The first stretching temperature is 80℃, and the second stretching temperature is 135℃. Superheated steam heats the fiber bundle to 105℃. In the bundling process, the crimping wheel width is 5×103dtex / mm, and the bus density variation of the bundled fibers is controlled within ±4%. The relaxation heat setting process uses a chain plate relaxation heat setting machine. The drying zone temperature is 110℃, and the heat setting zone temperature is 120℃. The drying heat setting time is 15min.

[0050] Example 6:

[0051] The antibacterial properties of Examples 1-5 and Comparative Examples 1-2 were tested using conventional microbial testing methods, and the results are shown in Table 1.

[0052] Table 1

[0053]

[0054] As shown in Table 1, the antibacterial properties of the antibacterial masterbatches obtained in Examples 1-5 are superior to those of the antibacterial masterbatches obtained in Comparative Examples 1-2. The poor antibacterial properties of Comparative Example 1 may be due to the uneven dispersion of copper ions on the boron nitride support, while those of Comparative Example 2 may be due to the loss of hydroxyl and amino functional groups in dopamine after calcination, thereby reducing its antibacterial properties.

Claims

1. A method for preparing antibacterial recycled polyester staple fiber, characterized in that, Includes the following steps: (1) Preparation of antibacterial masterbatch: Hexagonal boron nitride and dopamine were wet-milled to load dopamine onto a boron nitride matrix. The milled product was then placed in a copper salt solution for adsorption. The oxygen atoms on the catechol in dopamine complexed with metal ions through shared electrons, uniformly dispersing metallic copper onto the boron nitride-loaded dopamine precursor. After calcination in a tube furnace, a carbon layer was formed coating the boron nitride matrix. The calcined product and dispersant were then ultrasonically dispersed in an ethylene glycol solution to form an ethylene glycol dispersion. A catalyst is then added to the reaction system of ethylene glycol dispersion and terephthalic acid to prepare polyester through esterification and polycondensation. The polyester is then extruded, granulated, and dried to obtain polyester antibacterial masterbatch. The extrusion granulation process is divided into six zones, with the screw temperatures of the six zones being as follows: Zone 1: 220-250℃, Zone 2: 230-260℃, Zone 3: 250-280℃, Zone 4: 260-290℃, Zone 5: 260-290℃, Zone 6: 260-290℃. The mass ratio of hexagonal boron nitride to dopamine is 1:0.1-10; The copper salt solution is one of copper chloride solution, copper nitrate solution, or copper sulfate solution, and the concentration of the copper salt solution is 100-800 mg / L; The ball milling conditions are: ball mill speed 400 rpm, forward and reverse rotation for 5 minutes, with an interval of 30 seconds; The calcination conditions are: temperature 800-1200℃, holding time 2-4h; The dispersant includes one or a mixture of several of the following: white oil, zinc stearate, polyethylene wax, stearic acid, or ethylene bis-stearamide; The esterification catalyst is one of zinc acetate, cobalt acetate, or manganese acetate, and the amount of catalyst used is 0.001-0.06 wt% of the mass of terephthalic acid; the molar ratio of terephthalic acid to ethylene glycol is 1:1.1-1.6; the esterification reaction temperature is 220-260℃, the esterification pressure is 0.1MPa-0.4MPa, the polycondensation reaction temperature is 250-290℃, the polycondensation pressure is ≤100Pa (vacuum degree), and the intrinsic viscosity of the polyester is 0.1-0.5 dL / g. (2) Spinning process: The antibacterial masterbatch and recycled polyester raw materials are weighed according to a certain mass ratio, mixed and dried, and then obtained by spinning, ring blowing, oiling, bundling, stretching, crimping, relaxation heat setting, cutting and packaging processes.

2. The method for preparing antibacterial recycled polyester staple fiber according to claim 1, characterized in that, The recycled polyester raw material mentioned in step (1) is selected from one or a mixture of two of the following: fabric foam processed from waste polyester textiles or recycled polyester bottle flakes.

3. The method for preparing antibacterial recycled polyester staple fiber according to claim 1, characterized in that, The mass fractions of the antibacterial masterbatch and the recycled polyester raw material in step (2) are 1-4 parts of antibacterial masterbatch and 96-99 parts of recycled polyester.

4. The method for preparing antibacterial recycled polyester staple fiber according to claim 1, characterized in that, The mixing and drying conditions described in step (2) are as follows: a vacuum drum dryer is used for drying, with a vacuum degree below -0.09MPa, a rotation speed of 4r / min, a drying temperature of 110-150℃, and a drying time of 8-12h.

5. The method for preparing antibacterial recycled polyester staple fiber according to claim 1, characterized in that, Step (2) The spinning temperature is 270-285℃, and the temperature fluctuation is controlled within ±2℃; the cooling wind speed of the ring blower is 0.5-4.0m / s, the relative humidity is controlled within 65%-80%, and the wind temperature is controlled within 20-30℃; the oiling rate is controlled within 0.1%-0.2%.

6. The method for preparing antibacterial recycled polyester staple fiber according to claim 1, characterized in that, In step (2) of the bundling process, the width of the coiling wheel is (4.44-6.66)×10 3 The bus density variation of the bundled fiber is controlled within ±4%, with a density of dtex / mm.

7. The method for preparing antibacterial recycled polyester staple fiber according to claim 1, characterized in that, Step (2) The stretching process uses two stretching processes. The first stretching is carried out in a hot oil-water bath with the temperature controlled at 60-80℃. The second stretching uses superheated steam at 130-150℃ with a steam pressure greater than 0.1MPa to heat the filament bundle to 100-120℃.

8. The method for preparing antibacterial recycled polyester staple fiber according to claim 1, characterized in that, The relaxation heat setting process described in step (2) uses a chain plate relaxation heat setting machine. The temperature of the drying zone is 110-120℃, and the temperature of the heat setting zone is 120-130℃. The drying heat setting time is controlled at 15-20 minutes.

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