Method and device for preparing antibacterial meta-aramid filament by dry-wet spinning

Abstract

The application discloses a method and device for preparing antibacterial meta-aramid filaments by dry-wet spinning, and the method comprises the following steps: (1) preparing a nano-silver colloidal solution; (2) dissolving m-phenylenediamine in an N,N-dimethylacetamide solution, adding the nano-silver colloidal solution, and then adding m-phthaloyl chloride to generate a poly-m-phenylenediamine terephthalate polymer solution by low-temperature polycondensation; adding a neutralizing agent and performing vacuum defoaming; (3) extruding the resin stock solution from a spinneret, and then sequentially passing through a primary air layer, a solidification tank, a coagulation bath, water washing, drying, high-temperature stretching, heat setting, and heat stretching to prepare the dry-wet antibacterial meta-aramid filaments. The in-situ polymerization method enables the nano-silver powder and the resin to be fully combined, the chemical modification method enables the combination of the two to be more compact and not easy to fall off, and the problem that the antibacterial performance is not strong and durable is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of meta-aramid, and particularly relates to a method and device for preparing antibacterial meta-aramid filaments through dry-wet spinning. BACKGROUND

[0002] Aramid belongs to polyamide fibers. Aramid, as a high-tech fiber material, is widely used in individual protection, environmental protection, information communication, electronic and electrical fields. Meta-aramid was industrialized in 1967, and the product is named Nomex. Aramid industry in China is late and the technology is backward. Shandong Taihe New Material realized mass production of meta-aramid in 2004. With the rapid development of science and technology, aramid products are increasingly used in daily life. For example, modified antibacterial aramid fibers can be used in medical gloves, protective clothing and other products due to the high-temperature resistance and aging resistance of meta-aramid; the antibacterial aramid fibers can also be used in storage bags for urban environmental protection and sewage treatment; and the antibacterial aramid fibers can also be used in biological experiments in scientific research laboratories to prevent infection by microorganisms and bacteria.

[0003] Patent publication application No. CN113981560A, entitled "Antibacterial meta-aramid and preparation thereof", provides an antibacterial meta-aramid loaded with silver ion mesoporous material, which is obtained by blending antibacterial silver ions. However, the fiber strength obtained by the use method is low, the silver ion loaded mesoporous material is unevenly distributed, and the antibacterial meta-aramid cannot be used in high-performance fiber application fields. Patent publication application No. CN103233292A, entitled "Preparation method of meta-aramid fiber", provides a dry spinning preparation method. The nascent fiber obtained by removing the solvent through a hot channel has a compact structure. However, the residual fibrils in the fiber and a small amount of solvent wrapped by the fiber shell are not easy to remove, which has a great influence on the uniformity of the fiber. Patent publication application No. CN107815741A, entitled "Preparation method of meta-aramid filaments", provides a low-temperature solution polymerization process and a wet spinning technology. The wet spinning preparation of filaments has a slow spinning speed and low single-fiber strength. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the above-mentioned deficiencies and shortcomings in the background art, and to provide a method and device for preparing antibacterial meta-aramid filaments through dry-wet spinning.

[0005] To solve the above technical problems, the technical solution provided by the present application is as follows:

[0006] A method for preparing antibacterial meta-aramid filaments through dry-wet spinning, comprising the following steps:

[0007] (1) adding nano-silver powder into N,N-dimethylacetamide solution to prepare nano-silver colloidal solution;

[0008] (2) dissolving m-phenylenediamine in N,N-dimethylacetamide solution, adding the nano-silver colloidal solution prepared in step (1) to stir, then adding isophthaloyl chloride to generate poly-m-phenylene isophthalamide polymer solution by low-temperature polycondensation; adding neutralizing agent to mix uniformly, vacuum degassing to obtain nano-silver aramid resin stock solution with uniform distribution;

[0009] (3) extruding the nano-silver aramid resin stock solution from a spinneret, sequentially passing through a primary air layer, a solidification pool, a secondary air layer, a primary coagulation bath, a secondary coagulation bath, water washing, drying, high-temperature stretching, heat setting, and heat stretching to prepare meta-aramid filament of dry-wet antibacterial type.

[0010] The present application introduces silver in the form of nano-silver colloidal solution, and the nano-silver and m-phenylenediamine are fully stirred in N,N-dimethylacetamide solution, so that the nano-silver is uniformly dispersed and the diamine monomer is filled into the structure gap of the nano-silver; then isophthaloyl chloride is added to generate polymerization reaction, and the nano-silver particles are firmly combined with the polymer generated by the reaction.

[0011] Preferably, the preparation method of the nano-silver powder in step (1) is specifically as follows: mixing silver nitrate solution in N,N-dimethylacetamide solution, adding a reducing agent to reduce the silver nitrate into nano-silver during stirring, and then washing with water, filtering, and drying to obtain nano-silver powder;

[0012] Preferably, the mass concentration of the silver nitrate solution is 5-20%, the diameter of the nano-silver powder reduced by the reducing agent is 10-30 nm, and the specific surface area is 2000-5000 m 2 / g; the reducing agent includes one of hydrazine hydrate, tea polyphenol, or sodium hydroxide, and the concentration is 50-250 mmol / L;

[0013] Preferably, the preparation of the nano-silver colloidal solution in step (1) is specifically as follows: adding a dispersing agent dropwise at room temperature, and obtaining the nano-silver colloidal solution by ultrasonic oscillation; the addition amount of the nano-silver powder is 0.5%-2% of the mass fraction content of m-phenylenediamine; and the dispersing agent includes one of polyacrylic acid, dodecanol, or polydiallyldimethylammonium chloride, and the mass concentration is 0.5-2%.

[0014] Preferably, the m-phenylenediamine in step (2) is stirred at -20 to -10℃ for 0.5-1h after being added into the nanosilver colloidal solution; the low-temperature polycondensation is specifically as follows: 15%-25% of isophthaloyl chloride based on the total mass fraction of isophthaloyl chloride is added, the low-temperature polycondensation is carried out for 1-4h, the temperature is raised to 5-20℃, the acyl chloride is continuously added in batches, stirring is carried out, and the reaction is carried out for 0.5-3h at a reaction temperature of 20-40℃, and the low-temperature polycondensation is completed.

[0015] Preferably, the neutralizing agent in step (2) comprises one or more of lithium hydroxide, calcium hydroxide, potassium hydroxide, lithium carbonate, calcium carbonate or triethanolamine, the neutralization reaction temperature is 40-60℃, the pH value is adjusted to 6-8, the nanosilver aramid resin stock solution is obtained, and the apparent viscosity of the nanosilver aramid resin stock solution is 250-350 million centipoises.

[0016] Preferably, the spinneret hole number in step (3) is 25-10000 holes, the first-stage air layer height is 5-10cm, the second-stage air layer height is 10-20cm, the solidification pool temperature is 35-45℃, the organic solvent is DMAc, and the mass concentration is 65%-80%.

[0017] Preferably, the first-stage and second-stage coagulation bath concentrations in step (3) are 50-60% and 45-55% respectively, the temperature is 40-50℃; the washing temperature is 60-80℃, the drying temperature is 50-60℃, the high-temperature stretching multiple is 1.2-2.5 times, the heat setting temperature is 270-400℃, the heat stretching temperature is 280-360℃, and the heat stretching multiple is 1.5-6 times.

[0018] Under the same technical concept, the application further provides a device for preparing antibacterial meta-aramid filament by dry-wet spinning, which comprises a raw material storage system, an in-situ polymerization system and a dry-wet spinning system connected in sequence, the dry-wet spinning system comprises a solidification U-shaped duct, the U-shaped part of the solidification U-shaped duct is a solidification pool, and a traction pulley is arranged on the U-shaped part; the two sides of the U-shaped part are respectively a first-stage air layer straight pipe and a second-stage air layer straight pipe.

[0019] Preferably, the length of the first-stage air layer straight pipe is 2-10cm, and the length of the second-stage air layer straight pipe is 10-20cm.

[0020] Preferably, the raw material storage system comprises a nanosilver colloidal solution storage device, an N,N-dimethylacetamide solution storage device, an m-phenylenediamine storage device and an isophthaloyl chloride storage device; and the in-situ polymerization system comprises a microreactor.

[0021] Preferably, the solidified U-shaped duct is connected to the spinneret by a primary air layer straight pipe, and the secondary air layer straight pipe is sequentially connected to the primary coagulation pool, the secondary coagulation pool, the hot water washing device, the drum drying device, the stretching device, the heat setting device and the hot stretching device.

[0022] Compared with the prior art, the present application has the following advantages:

[0023] (1) The present application provides a method for preparing antibacterial meta-aramid filament by dry-wet method, which fully combines nano-silver powder and resin by in-situ polymerization, and makes the combination more compact and less likely to fall off by chemical modification, thereby solving the problem of poor durability of antibacterial performance. In the in-situ polymerization process, the nano-silver powder is uniformly dispersed in the resin by rapid stirring. Compared with the blending method, which can only spread nano-silver on the surface of the filament, the antibacterial filament prepared by in-situ polymerization has uniform distribution of nano-silver on the inner and outer walls, so even if the surface of the fiber is worn, it will not affect its antibacterial property. The prepared antibacterial aramid fiber can be used for medical protection and biological experiments.

[0024] (2) The present application provides a solidified U-shaped duct which combines the characteristics of wet and dry methods. In the design of the traditional dry-wet method, two air layers are designed. The fiber forms a thin shell through the first hot air layer, enters the solidification duct, and the inside of the fiber is solidified. Through the second hot air layer, the inner layer of the fiber is further solidified to form a more compact structure. This solves the problems of low strength and slow spinning speed of antibacterial aramid fiber filament prepared by wet method, and compared with dry spinning, the requirements for fiber raw materials, equipment and cost are low, which is convenient for cost control and large-scale production of fiber filament, and improves the spinning speed and fiber strength. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0026] Figure 1 is a flow chart of the method for preparing antibacterial meta-aramid filament by dry-wet method;

[0027] Figure 2 is a schematic diagram of the solidified U-shaped duct of embodiment 1;

[0028] Wherein: 1, primary air layer straight pipe; 2, secondary air layer straight pipe; 3, solidification pool. DETAILED DESCRIPTION

[0029] For the convenience of understanding the present application, the present application will be described more fully below with reference to the accompanying drawings and preferred embodiments of the application, but the scope of the protection of the present application is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The materials used in the present application are only for the purpose of describing specific embodiments, and are not intended to limit the scope of protection of the present application.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present application can be purchased on the market or can be prepared by existing methods.

[0032] Example 1

[0033] This embodiment uses a dry-wet spinning device to prepare antibacterial meta-aramid filament. The devices used in subsequent examples and comparative examples are also the same as in Example 1. The device includes a raw material storage system, an in-situ polymerization system, and a dry-wet spinning system connected in sequence. The dry-wet spinning system includes a solidification U-shaped duct, and the U-shaped part of the solidification U-shaped duct is a solidification pool 3. The two sides of the U-shaped part are a first air layer straight pipe 1 and a second air layer straight pipe 2, respectively.

[0034] The raw material storage system includes a nanosilver colloidal solution storage device, an N,N-dimethylacetamide solution storage device, a m-phenylenediamine storage device, and a m-phenylenediformyl chloride storage device. The in-situ polymerization system includes a microreactor.

[0035] As shown in Figure 2 The length of the first air layer straight pipe 1 is 5 cm, and the length of the second air layer straight pipe 2 is 10 cm. The U-shaped part of the solidification U-shaped duct is provided with a traction pulley made of polytetrafluoroethylene, which is fixed in the duct by a stainless steel pipe. When the spinneret in the spinning system enters the solidification U-shaped duct, the traction pulley plays a role in traction and transportation of the yarn.

[0036] The first air layer straight pipe 1 of the solidification U-shaped duct is connected to the spinneret plate, and the second air layer straight pipe 2 is connected to the first coagulation pool, the second coagulation pool, the hot water washing device, the drum drying device, the stretching device, the heat setting device, and the hot stretching device in sequence.

[0037] This embodiment provides a method for preparing antibacterial meta-aramid filament by dry-wet spinning. The specific process is shown in Figure 1

[0038] ​The nanosilver powder is added into N,N-dimethylacetamide solution solvent, a NaOH dispersant with a mass fraction of 0.5% of the nanosilver powder is added dropwise at normal temperature, and a nanosilver colloidal solution is obtained through sufficient ultrasonic oscillation; the nanosilver colloidal solution and m-phenylenediamine are added into the N,N-dimethylacetamide solution, m-phthaloyl chloride is added in batches, and a poly-m-phenyleneterephthalamide polymer solution is generated through low-temperature polycondensation, the molar ratio of the m-phenylenediamine and the m-phthaloyl chloride is 1:1.05, the mixture is uniformly mixed after neutralization by calcium hydroxide, and vacuum degassing is performed, so that a uniform aramid resin stock solution containing 0.5% of nanosilver is obtained, wherein the resin solid content is 18.8%, and the resin apparent viscosity is 226 million;

[0039] The resin solution is extruded from a 500-hole spinneret, passes through a first-stage 5cm air layer, a solidification pool with a concentration of 80%, and then passes through a second-stage 10cm air layer, a U-shaped pipeline with a temperature of 35°C, and is formed through a primary and secondary coagulation bath with concentrations of 40% and 45%. The hot water pool stretching ratio is 1.5 times, the temperature is 80°C, the secondary hot water washing temperature is 70°C, the filament is dried on a 50°C roller, high-temperature stretching is performed at 300°C with a stretching ratio of 1.6 times, heat setting is performed in a 320°C oven, and the filament is obtained after oiling and winding.

[0040] Example 2

[0041] The nanosilver powder is added into N,N-dimethylacetamide solution solvent, a NaOH dispersant with a mass fraction of 0.5% of the nanosilver powder is added dropwise at normal temperature, and a nanosilver colloidal solution is obtained through sufficient ultrasonic oscillation; the nanosilver colloidal solution and m-phenylenediamine are added into the N,N-dimethylacetamide solution, m-phthaloyl chloride is added in batches, and a poly-m-phenyleneterephthalamide polymer solution is generated through low-temperature polycondensation, the molar ratio of the m-phenylenediamine and the m-phthaloyl chloride is 1:1.08, the mixture is uniformly mixed after neutralization by calcium hydroxide, and vacuum degassing is performed, so that a uniform aramid resin stock solution containing 0.5% of nanosilver is obtained, wherein the resin solid content is 19.6%, and the resin apparent viscosity is 247 million;

[0042] The resin solution is extruded from a 500-hole spinneret, passes through a first-stage 7cm air layer, a solidification pool with a concentration of 85%, and then passes through a second-stage 10cm air layer, a U-shaped pipeline with a temperature of 40°C, and is formed through a primary and secondary coagulation bath with concentrations of 40% and 45%. The hot water pool stretching ratio is 1.8 times, the temperature is 75°C, the secondary hot water washing temperature is 70°C, the filament is dried on a 50°C roller, high-temperature stretching is performed at 300°C with a stretching ratio of 2 times, heat setting is performed in a 320°C oven, and the filament is obtained after oiling and winding.

[0043] Example 3

[0044] The nano-silver powder is added into N,N-dimethylacetamide solution solvent, a NaOH dispersant with a mass fraction of 0.8% of the nano-silver powder is added dropwise at normal temperature, and a nano-silver colloidal solution is obtained by ultrasonic oscillation; the nano-silver colloidal solution and m-phenylenediamine are added into the N,N-dimethylacetamide solution, m-phthaloyl chloride is added in batches, and a poly-m-phenyleneterephthalamide polymer solution is generated by low-temperature polycondensation, the molar ratio of m-phenylenediamine to m-phthaloyl chloride is 1:1.12, the solution is uniformly mixed after neutralization by calcium hydroxide, and vacuum degassing is performed, so that a uniform aramid resin stock solution containing 0.8% of nano-silver is obtained, wherein the resin solid content is 21.1%, and the resin apparent viscosity is 324 million;

[0045] The resin solution is extruded from a 500-hole spinneret, passes through a first 5cm air layer, a solidification pool with a concentration of 85%, and then passes through a second 10cm air layer, a U-shaped pipeline temperature of 35°C, and is formed by a primary and secondary coagulation bath with concentrations of 42% and 48%. The hot water pool stretching ratio is 1.7 times, the temperature is 75°C, the secondary hot water washing temperature is 70°C, the filament is dried by a 50°C roller, high-temperature stretching at 280°C with a stretching ratio of 2.4 times, and then heat setting in a 300°C oven, oiling and winding to obtain the filament.

[0046] Example 4

[0047] The nano-silver powder is added into N,N-dimethylacetamide solution solvent, a NaOH dispersant with a mass fraction of 0.8% of the nano-silver powder is added dropwise at normal temperature, and a nano-silver colloidal solution is obtained by ultrasonic oscillation; the nano-silver colloidal solution and m-phenylenediamine are added into the N,N-dimethylacetamide solution, m-phthaloyl chloride is added in batches, and a poly-m-phenyleneterephthalamide polymer solution is generated by low-temperature polycondensation, the molar ratio of m-phenylenediamine to m-phthaloyl chloride is 1:1.12, the solution is uniformly mixed after neutralization by calcium hydroxide, and vacuum degassing is performed, so that a uniform aramid resin stock solution containing 0.8% of nano-silver is obtained, wherein the resin solid content is 21.1%, and the resin apparent viscosity is 324 million;

[0048] The resin solution is extruded from a 500-hole spinneret, passes through a first 5cm air layer, a solidification pool with a concentration of 85%, and then passes through a second 10cm air layer, a U-shaped pipeline temperature of 35°C, and is formed by a primary and secondary coagulation bath with concentrations of 42% and 48%. The hot water pool stretching ratio is 1.7 times, the temperature is 75°C, the secondary hot water washing temperature is 70°C, the filament is dried by a 50°C roller, high-temperature stretching at 280°C with a stretching ratio of 2.4 times, and then heat setting in a 300°C oven, oiling and winding to obtain the filament.

[0049] Example 5

[0050] The nano-silver powder is added into N,N-dimethylacetamide solution solvent, a NaOH dispersant with a mass fraction of 1% of the nano-silver powder is added dropwise at normal temperature, and a nano-silver colloidal solution is obtained by ultrasonic oscillation; the nano-silver colloidal solution and m-phenylenediamine are added into the N,N-dimethylacetamide solution, m-phthaloyl chloride is added in batches, and a poly-m-phenyleneterephthalamide polymer solution is generated by low-temperature polycondensation, the molar ratio of m-phenylenediamine to m-phthaloyl chloride is 1:1.14, the solution is uniformly mixed after neutralization by calcium hydroxide, and vacuum degassing is performed, so that a uniform aramid resin stock solution containing 1% of nano-silver is obtained, wherein the resin solid content is 22.5%, and the resin apparent viscosity is 367000;

[0051] The resin solution is extruded from a 500-hole spinneret, passes through a first 5 cm air layer, a solidification pool with a concentration of 80%, and then passes through a second 10 cm air layer, a U-shaped pipeline temperature of 40°C, and is formed by a primary and secondary coagulation bath with concentrations of 45% and 40%. The hot water pool stretching ratio is 2 times, the temperature is 80°C, the secondary hot water washing temperature is 70°C, the filament is dried by a 50°C roller, high-temperature stretching at 300°C with a stretching ratio of 1.8 times, heat setting in a 310°C oven, and oiling and winding, to obtain the filament.

[0052] Example 6

[0053] The nano-silver powder is added into N,N-dimethylacetamide solution solvent, a NaOH dispersant with a mass fraction of 1% of the nano-silver powder is added dropwise at normal temperature, and a nano-silver colloidal solution is obtained by ultrasonic oscillation; the nano-silver colloidal solution and m-phenylenediamine are added into the N,N-dimethylacetamide solution, m-phthaloyl chloride is added in batches, and a poly-m-phenyleneterephthalamide polymer solution is generated by low-temperature polycondensation, the molar ratio of m-phenylenediamine to m-phthaloyl chloride is 1:1.02, the solution is uniformly mixed after neutralization by calcium hydroxide, and vacuum degassing is performed, so that a uniform aramid resin stock solution containing 1.2% of nano-silver is obtained, wherein the resin solid content is 18.4%, and the resin apparent viscosity is 207000;

[0054] The resin solution is extruded from a 500-hole spinneret, passes through a first 5 cm air layer, a solidification pool with a concentration of 75%, and then passes through a second 15 cm air layer, a U-shaped pipeline temperature of 40°C, and is formed by a primary and secondary coagulation bath with concentrations of 40% and 50%. The hot water pool stretching ratio is 1.3 times, the temperature is 80°C, the secondary hot water washing temperature is 70°C, the filament is dried by a 50°C roller, high-temperature stretching at 280°C with a stretching ratio of 2 times, heat setting in a 300°C oven, and oiling and winding, to obtain the filament.

[0055] Comparative Example 1

[0056] The m-phenylenediamine and m-phthaloyl chloride are low-temperature polycondensed to form a poly-m-phenylenediamine-m-phthaloyl polymer solution, the molar ratio of the m-phenylenediamine and the m-phthaloyl chloride is 1:1.05, the solution is mixed uniformly after neutralization by calcium hydroxide and vacuum degassing, and the obtained aramid resin stock solution has a resin solid content of 19.2% and a resin apparent viscosity of 237 million;

[0057] The resin solution is extruded from a 500-hole spinneret, passes through a first 5 cm air layer, a solidification pool with a concentration of 75%, and then passes through a second 10 cm air layer, a U-shaped pipe with a temperature of 45°C, and is formed by a primary and secondary coagulation bath with concentrations of 42% and 48%. The hot water pool stretching ratio is 1.5 times, the temperature is 80°C, the secondary hot water washing temperature is 70°C, the filament is dried by a 50°C roller, high-temperature stretched at 280°C with a stretching ratio of 2.5 times, heat set in a 300°C oven, oiled, and wound up to obtain a filament.

[0058] Comparative Example 2

[0059] The nano-silver powder is added to an N,N-dimethylacetamide solution solvent, a mass fraction of 1% of a NaOH dispersant is added dropwise at room temperature, and a nano-silver colloidal solution is obtained by ultrasonic oscillation; the nano-silver colloidal solution and m-phenylenediamine are added to the N,N-dimethylacetamide solution, and m-phthaloyl chloride is added in batches, low-temperature polycondensation is performed to form a poly-m-phenylenediamine-m-phthaloyl polymer solution, the molar ratio of the m-phenylenediamine and the m-phthaloyl chloride is 1:1.05, the solution is mixed uniformly after neutralization by calcium hydroxide, and vacuum degassing is performed, and the obtained aramid resin stock solution has a resin solid content of 19.8% and a resin apparent viscosity of 246 million;

[0060] The resin solution is extruded from a 500-hole spinneret, directly enters a primary and secondary coagulation bath to form, and has concentrations of 40% and 50%. The hot water pool stretching ratio is 1.7 times, the temperature is 80°C, the secondary hot water washing temperature is 70°C, the filament is dried by a 50°C roller, high-temperature stretched at 280°C with a stretching ratio of 2.2 times, heat set in a 300°C oven, oiled, and wound up to obtain a filament.

[0061] Comparative Example 3

[0062] The nano-silver powder is added into N,N-dimethylacetamide solution solvent, a mass fraction of 1% of the nano-silver powder NaOH dispersant is added dropwise at normal temperature, and the nano-silver colloidal solution is obtained by ultrasonic oscillation; the m-phenylenediamine is added into the N,N-dimethylacetamide solution, the isophthaloyl chloride is added in batches, the poly-m-phenylenediamine isophthaloyl polymer solution is generated by low-temperature polycondensation, the molar ratio of the m-phenylenediamine and the isophthaloyl chloride is 1:1.05, the nano-silver colloidal solution is added into the polymer solution and stirred for 3 hours, the mixture is uniformly mixed after neutralization by calcium hydroxide, and the aramid resin stock solution containing 1% of nano-silver is obtained by vacuum degassing, wherein the resin solid content is 21.8%, and the apparent viscosity of the resin is 255 million;

[0063] The resin solution is extruded from a 500-hole spinneret plate, directly enters a primary and secondary coagulation bath for forming, and the concentration is 40% and 50%. The hot water pool stretching ratio is 1.7 times, the temperature is 80°C, the secondary hot water washing temperature is 70°C, the yarn is dried by a 50°C roller, high-temperature stretching is performed at 280°C, the stretching ratio is 2.2 times, the yarn is heat set in a 300°C oven, is oiled, and is wound up to obtain the filament.

[0064]

[0065]

Claims

1. A method for preparing antibacterial meta-aramid filaments by dry-wet spinning, characterized in that, Includes the following steps: (1) Add nano-silver powder to N,N-dimethylacetamide solution to prepare nano-silver colloidal solution; (2) Dissolve m-phenylenediamine in N,N-dimethylacetamide solution, add the nano-silver colloidal solution prepared in step (1), stir at -20℃ to -10℃ for 0.5-1h, then add isophthaloyl chloride, add isophthaloyl chloride accounting for 15% to 25% of the total isophthaloyl chloride mass fraction, perform low-temperature polycondensation reaction for 1 to 4h, raise the temperature to 5 to 20℃, continue to add acyl chloride in batches, stir, react for 0.5 to 3h, the reaction temperature is 20 to 40℃, and generate poly(m-phenylenediamine isophthaloyl) polymer solution; add neutralizing agent and mix evenly, degas under vacuum to obtain uniformly distributed nano-silver aramid resin stock solution; (3) The nano-silver aramid resin stock solution is extruded from the spinneret and passed through the first-stage air layer, curing tank, second-stage air layer, first-stage coagulation bath, second-stage coagulation bath, water washing, drying, high-temperature stretching, heat setting, and hot stretching to prepare dry and wet antibacterial meta-aramid filament.

2. The method as described in claim 1, characterized in that, The specific method for preparing the nano-silver powder in step (1) is as follows: silver nitrate solution is mixed in N,N-dimethylacetamide solution, and a reducing agent is added during stirring to reduce silver nitrate to nano-silver. After washing with water, filtering and drying, nano-silver powder is obtained.

3. The method as described in claim 2, characterized in that, The silver nitrate solution has a mass concentration of 5-20%, and the reduced silver nanoparticles have a diameter of 10-30 nm and a specific surface area of ​​2000-5000 m². 2 / g; the reducing agent includes hydrazine hydrate and one of tea polyphenols, with a concentration of 50-250 mmol / L.

4. The method as described in claim 1, characterized in that, The preparation of the nano-silver colloidal solution in step (1) is as follows: a dispersant is added dropwise at room temperature, and the nano-silver colloidal solution is obtained by full ultrasonic vibration; the amount of nano-silver powder added is 0.5% to 2% of the mass fraction of m-phenylenediamine; the dispersant includes one of polyacrylic acid, dodecyl alcohol or polydiallyl dimethyl ammonium chloride, with a mass concentration of 0.5% to 2%.

5. The method as described in claim 1, characterized in that, The neutralizing agent in step (2) includes one or more of lithium hydroxide, calcium hydroxide, potassium hydroxide, lithium carbonate, calcium carbonate or triethanolamine. The neutralization reaction temperature is 40-60℃, and the pH value is adjusted to 6-8 to obtain nano-silver aramid resin stock solution. The apparent viscosity of the nano-silver aramid resin stock solution is 250,000-350,000 centipoise.

6. The method as described in claim 1, characterized in that, In step (3), the spinneret has 25 to 10,000 holes, the primary air layer height is 5 to 10 cm, the secondary air layer height is 10 to 20 cm, the curing bath temperature is 35 to 45°C, the organic solvent is DMAc, and the mass concentration is 65% to 80%. In step (3), the primary and secondary coagulation baths have concentrations of 50 to 60% and 45 to 55%, respectively, and a temperature of 40 to 50°C. The washing temperature is 60 to 80°C, the drying temperature is 50 to 60°C, the high-temperature stretching ratio is 1.2 to 2.5 times, the heat setting temperature is 270 to 400°C, the hot stretching temperature is 280 to 360°C, and the hot stretching ratio is 1.5 to 6 times.

7. An apparatus for preparing antibacterial meta-aramid filaments by wet-dry spinning, the apparatus comprising a raw material storage system, an in-situ polymerization system, and a wet-dry spinning system connected in sequence, characterized in that, The dry-wet spinning system includes a solidification U-shaped channel, the U-shaped part of which is a solidification tank, and a traction pulley is installed in the U-shaped part; the two sides of the U-shaped part are a primary air layer straight pipe and a secondary air layer straight pipe, respectively; the primary air layer straight pipe of the solidification U-shaped channel is connected to the spinneret, and the secondary air layer straight pipe is sequentially connected to the primary solidification tank, the secondary solidification tank, the hot water washing device, the drum drying device, the stretching device, the heat setting device, and the hot stretching device.

8. The apparatus as claimed in claim 7, characterized in that, The length of the straight pipe for the primary air layer is 2–10 cm, and the length of the straight pipe for the secondary air layer is 10–20 cm.

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