Anion-coated artificial fiber as well as preparation method and application thereof

Abstract

The invention discloses a negative ion coated artificial fiber as well as a preparation method and application thereof. The artificial fiber comprises modified tourmaline powder, polyester fiber and a surfactant, the preparation process comprises the steps of preparation of the tourmaline finishing agent, preparation of the polyester fibers and preparation of the negative ion artificial fibers through a blending method. According to the preparation method, the crushed and color-changed tourmaline powder is subjected to surface coating by using the surface modifier, so that the surface energy of the powder can be effectively reduced, particle aggregation is reduced, the dispersity of the powder in a non-polar medium is improved, and the prepared polyester fiber and the modified tourmaline powder are blended and spun, so that the preparation of the negative ion coated artificial fiber is completed; the anion fiber shows unique advantages in the fields of clothes, medical treatment, industrial filtration and the like by virtue of the characteristic of releasing anions, and is extremely wide in application.

Description

Technical Field

[0001] The present invention relates to the technical field of artificial fibers and production thereof, in particular to an artificial fiber coated with negative ions and a preparation method and application thereof. Background Art

[0002] Negative ions are active particles beneficial to the environment and health, known as "vitamins of the air." They can purify the air, kill bacteria, and improve blood circulation and metabolism. They are now being increasingly researched in functional materials. Artificial fibers are a staple of the textile industry, and adding new functionalities to them can better meet people's needs for a healthy and comfortable lifestyle. If artificial fibers were equipped with the ability to release negative ions, textiles could maintain long-term health benefits, with potential applications in clothing, household items, medical supplies, and more. Therefore, the development of high-performance, negative ion-functionalized artificial fibers has become a key focus of the industry. However, current technology for producing negative ion synthetic fibers still faces numerous challenges. When using a blended spinning method, negative ion particles like tourmaline don't bond well with the fiber material. Adding too much will cause them to stick together, leading to broken and fuzzy yarns during spinning; adding too little will not release sufficient negative ions. Using a surface coating method, the coating simply adheres to the fiber surface and easily falls off after washing or excessive friction, quickly degrading the negative ion function. Furthermore, tourmaline, a commonly used negative ion material, has its own shortcomings. Natural tourmaline has numerous internal structural defects, and untreated, its negative ion release is inefficient and unstable. Furthermore, the micron-sized tourmaline particles tend to clump together during processing, creating ineffective areas and further compromising the fiber's negative ion performance. These issues make it difficult for existing negative ion synthetic fibers to simultaneously achieve functional effectiveness, durability, and stability during processing, limiting their large-scale production and use. Summary of the Invention

[0003] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a negative ion coated artificial fiber and its preparation method and application.

[0004] In order to achieve the above object, the present invention proposes the following technical solutions: A method for preparing a negative ion-coated artificial fiber comprises the following steps: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, and then wet ball mill for 1-4 hours, filter, and dry to obtain tourmaline powder; S102, using concentrated acid and the tourmaline powder of S101 in a mass ratio of 4:1 and fully stirring and mixing at room temperature for 1-2 hours, filtering, then washing with clean water, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 20-30 minutes, raising the temperature to 70-80° C., adding acrylic acid monomer and potassium persulfate aqueous solution with a mass concentration of 10%-30% dropwise to the reactor, respectively, keeping the temperature at 75° C. for reaction for 2-4 hours, and cooling to room temperature to obtain polyacrylic acid; S104, adding the acid-modified tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 40-70° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid, and molecular sieves in S103, reacting with mechanical stirring for 2-4 hours, vacuum filtering, and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.2-1.8 are reacted at 220-240° C. until the water output stabilizes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.02%-0.05% Sb2O3 and 0.01%-0.03% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for reaction for 3-6 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by solution spinning method: S301, vacuum melting the polyester chips of S203 at 250-280°C, adding the polyacrylic acid-coated tourmaline composite particles of S104 in a mass ratio of 95-99:1-5, and then adding Sb(Ac)3 accounting for 0.01%-0.5% of the total system, mechanically stirring, and reacting for 10-15 minutes to obtain molten negative ion fibers; S302, the volume flow rate is accurately measured by the metering pump to 50-100cm 3 / min, the molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded from the 0.2-0.4mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120-150℃, heated to 150-180℃, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

[0005] Preferably, the purpose of soaking the tourmaline particles in 1% hydrochloric acid in S101 is to remove impurities on the particle surface and expose the hydroxyl sites required for modification.

[0006] Preferably, the main purpose of treating the tourmaline with concentrated acid in S102 is to change its color. Currently, most tourmaline on the market is mainly black, and dyeing is limited after it is made into fiber. A whitening operation can be performed to remove ferrous oxide. Taking concentrated hydrochloric acid as an example, the relevant reaction equation is as follows: 2HCl+Fe2O3·SiO2→FeCl3+H2O+SiO2 2HCl+FeO·SiO2→FeCl2+H2O+SiO2 4HCl+FeO·SiO2→FeCl2+H2O+SiO2 4FeO·SiO2+3O2→2Fe2O3+SiO2 4FeO·SiO2+O2+2HCl→4FeCl3+6H2O+SiO2 Preferably, in S103, acrylic acid monomer undergoes a free radical polymerization reaction initiated by potassium persulfate as an initiator, and the related reaction is as follows: Chain initiation stage: potassium persulfate forms free radical R· under heating conditions; R·+CH2=CHCOOH→R-CH2-CHCOOH; Chain growth stage: monomer free radicals undergo addition reaction with double bonds of other acrylic monomers; R-CH2−CHCOOH+nCH2=CHCOOH→R-(-CH2−CHCOOH-) n -CH2−CHCOOH; Chain termination stage: The activity of the growing free radicals will eventually disappear and the polymerization reaction will stop.

[0007] Preferably, in S104, the carboxyl groups in the polyacrylic acid and the hydroxyl groups in the modified tourmaline powder undergo an esterification reaction under the catalysis of p-toluenesulfonic acid to complete the coating of the tourmaline powder with the polyacrylic acid. On the one hand, this solves the dispersibility problem of tourmaline in non-polar solutions. On the other hand, the polyacrylic acid reacts with the tourmaline to form an ester, which is more evenly fused with the polyester fiber when melted. The molecular sieve is used as a dehydrating agent in this reaction to adsorb water produced by the esterification and promote the esterification reaction.

[0008] Preferably, the temperature in S201 is in the range of 220-240° C. to reduce the volatilization of ethylene glycol. The reaction is continuously stirred to ensure full contact of the materials. At the same time, the generated water is separated from the excess ethylene glycol through a distillation column, the water is discharged after condensation, and the ethylene glycol is refluxed to the reactor.

[0009] Preferably, the polycondensation reaction in S202 needs to be carried out at a high temperature. The high temperature can increase the reaction rate, promote the growth of the molecular chain, and cause an excess of ethylene glycol. The final product is a hydroxyl-terminated polyester.

[0010] Preferably, the polyester fiber in S3 is stable at 250-280°C and is not easily hydrolyzed or broken in the absence of a catalyst. The polyacrylic acid reacts with the hydroxyl groups on the surface of the tourmaline to form an ester bond, which increases its melting point and improves its thermal stability. The hydroxyl groups in the polyester fiber can react with the carboxyl groups on the composite particles in a molten state under the catalysis of Sb(Ac)3 to form an esterification reaction to form a three-dimensional structure. However, this needs to be carried out under vacuum conditions to remove the generated water in time.

[0011] Preferably, the volume flow of the molten mixture in S3 is accurately measured by a metering pump. The purpose of accurate metering is to ensure the uniformity of the size of the continuous filaments during spinning. The purpose of stretching is to enhance the fiber strength. Maintaining it at 150°C for 0.5-1 second can eliminate internal stress and fix the orientation structure, thereby reducing the boiling water shrinkage of the finished fiber.

[0012] The present invention also provides anion-coated man-made fibers prepared by the above-mentioned preparation method. First, concentrated acid is used to modify tourmaline powder, which is then coated with polyacrylic acid. Finally, the polyacrylic acid-coated tourmaline composite particles are blended with polyester to prepare anion-coated man-made fibers.

[0013] In addition, the present invention also applies the aforementioned negative ion-coated artificial fibers to daily clothing, medical and other fields, such as daily underwear, socks, home clothes, etc. In the medical field, they are mostly used for medical work clothes, patient gowns, rehabilitation protective gear and medical bed sheets, etc.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. In the prior art, natural tourmaline is mostly dark, such as black or brown. Adding it to fibers can easily darken the base color, interfering with dyeing results, requiring large amounts of dye to cover the color or only producing dark fibers. The present invention uses targeted color-changing treatment to adjust tourmaline to a lighter color, eliminating interference with fiber dyeing at the source. This not only broadens the fiber's dyeing color range, adapting to a variety of light colors such as light pink and light blue, but also avoids the uneven coloring caused by dark tourmaline.

[0015] 2. Conventional technologies often use silane coupling agents or stearic acid to modify tourmaline. While these agents improve dispersibility, they have weak interfacial bonding with the polyester matrix and are prone to agglomeration even at high addition levels. The present invention uses polyacrylic acid for modification. The carboxyl groups on its molecular chain can form ester bonds with the hydroxyl groups on the tourmaline surface, generating polar interactions with the ester groups on the polyester molecular chain. This structure improves the dispersion uniformity of tourmaline in the matrix by over 40% and significantly reduces the spinning breakage rate caused by agglomeration. Furthermore, the polyacrylic acid coating of the tourmaline powder ensures the integrity of its crystal structure.

[0016] 3. In existing technologies, co-blending often results in reduced spinnability due to poor powder dispersion, and surface coating methods often suffer from the problem of functional layer shedding. The present invention utilizes a co-melting preparation process to chemically react and mix tourmaline with a hydroxyl-terminated polyester matrix in a molten state, avoiding the interfacial defects of traditional blending. Furthermore, the co-melting process allows tourmaline and polyacrylic acid to form a stable, integrated structure, addressing the industry's pain point of poor functional durability. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0018] Example 1: A method for preparing a negative ion-coated artificial fiber comprises the following steps: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, and then wet ball mill for 3 hours, filter, and dry to obtain tourmaline powder; S102, using concentrated nitric acid and the tourmaline powder in S101 in a mass ratio of 4:1 at room temperature for 1 hour, washing with clean water, filtering, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 30 minutes, raising the temperature to 70° C., and dropwise adding 20% ​​by mass concentration of acrylic acid monomer and 40:5 by mass ratio of potassium persulfate aqueous solution into the reactor, respectively. Keep the temperature at 75° C. for reaction for 3 hours, and cool to room temperature to obtain a polyacrylic acid product; S104, adding the tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 60° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid (2% by weight of the polyacrylic acid), and molecular sieves of the same weight as the polyacrylic acid in S103, wherein the ratio of polyacrylic acid to modified tourmaline powder is 1:8, reacting for 3 h with mechanical stirring, and vacuum filtering and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.5 are reacted at 220° C. until the water output is stable and exceeds 90% of the theoretical amount, and the reaction is continued for 20 minutes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.03% Sb2O3 and 0.02% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for 4 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by blending method: S301, the polyester chips in S203 were vacuum melted at 250°C, and the polyacrylic acid-coated tourmaline composite particles in S104 were added in a mass ratio of 97:3, and then 0.1% of Sb(Ac)3 was added to the total amount of the system, and mechanical stirring was performed and the reaction was carried out for 12 minutes to obtain molten negative ion fibers; S302. The volume flow rate is accurately measured by a metering pump to be 50-100 cm³ / min. The molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded through a 0.2-0.4 mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120°C, heated to 150°C, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

[0019] Example 2: A method for preparing a negative ion-coated artificial fiber comprises the following steps: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, and then wet ball mill for 3 hours, filter, and dry to obtain tourmaline powder; S102, using concentrated hydrochloric acid and the tourmaline powder in S101 in a mass ratio of 4:1 at room temperature for 1 hour, washing with clean water, filtering, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 30 minutes, raising the temperature to 70° C., and dropwise adding 20% ​​by mass concentration of acrylic acid monomer and 40:5 by mass ratio of potassium persulfate aqueous solution into the reactor, respectively. Keep the temperature at 75° C. for reaction for 3 hours, and cool to room temperature to obtain a polyacrylic acid product; S104, adding the tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 60° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid (2% by weight of the polyacrylic acid), and molecular sieves of the same weight as the polyacrylic acid in S103, wherein the ratio of polyacrylic acid to modified tourmaline powder is 1:10, reacting for 3 h with mechanical stirring, and vacuum filtering and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.5 are reacted at 220° C. until the water output is stable and exceeds 90% of the theoretical amount, and the reaction is continued for 20 minutes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.03% Sb2O3 and 0.02% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for 4 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by blending method: S301, the polyester chips in S203 were vacuum melted at 250°C, and the polyacrylic acid-coated tourmaline composite particles in S104 were added in a mass ratio of 97:3, and then 0.1% of Sb(Ac)3 was added to the total amount of the system, and mechanical stirring was performed and the reaction was carried out for 12 minutes to obtain molten negative ion fibers; S302. The volume flow rate is accurately measured by a metering pump to be 50-100 cm³ / min. The molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded through a 0.2-0.4 mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120°C, heated to 150°C, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

[0020] Example 3: A method for preparing a negative ion-coated artificial fiber comprises the following steps: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, and then wet ball mill for 3 hours, filter, and dry to obtain tourmaline powder; S102, using concentrated nitric acid and the tourmaline powder in S101 in a mass ratio of 4:1 at room temperature for 1 hour, washing with clean water, filtering, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 30 minutes, raising the temperature to 70° C., and dropwise adding 20% ​​by mass concentration of acrylic acid monomer and 40:5 by mass ratio of potassium persulfate aqueous solution into the reactor, respectively. Keep the temperature at 75° C. for reaction for 3 hours, and cool to room temperature to obtain a polyacrylic acid product; S104, adding the tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 60° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid (2% by weight of the polyacrylic acid), and molecular sieves of the same weight as the polyacrylic acid in S103, wherein the ratio of polyacrylic acid to modified tourmaline powder is 1:8, reacting for 3 h with mechanical stirring, and vacuum filtering and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.5 are reacted at 220° C. until the water output is stable and exceeds 90% of the theoretical amount, and the reaction is continued for 20 minutes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.03% Sb2O3 and 0.02% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for 4 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by blending method: S301, the polyester chips in S203 are vacuum melted at 250°C, and the polyacrylic acid-coated tourmaline composite particles in S104 are added in a mass ratio of 99:1, and then 0.1% of Sb(Ac)3 is added to the total amount of the system, and mechanical stirring is performed and the reaction is carried out for 12 minutes to obtain molten negative ion fibers; S302. The volume flow rate is accurately measured by a metering pump to be 50-100 cm³ / min. The molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded through a 0.2-0.4 mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120°C, heated to 150°C, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

[0021] Example 4: A method for preparing a negative ion-coated artificial fiber comprises the following steps: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, and then wet ball mill for 3 hours, filter, and dry to obtain tourmaline powder; S102, using concentrated nitric acid and the tourmaline powder in S101 in a mass ratio of 4:1 at room temperature for 1 hour, washing with clean water, filtering, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 30 minutes, raising the temperature to 70° C., and dropwise adding 20% ​​by mass concentration of acrylic acid monomer and 40:5 by mass ratio of potassium persulfate aqueous solution into the reactor, respectively. Keep the temperature at 75° C. for reaction for 3 hours, and cool to room temperature to obtain a polyacrylic acid product; S104, adding the tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 60° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid (2% by weight of the polyacrylic acid), and molecular sieves of the same weight as the polyacrylic acid in S103, wherein the ratio of polyacrylic acid to modified tourmaline powder is 1:8, reacting for 3 h with mechanical stirring, and vacuum filtering and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.5 are reacted at 220° C. until the water output is stable and exceeds 90% of the theoretical amount, and the reaction is continued for 20 minutes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.03% Sb2O3 and 0.02% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for 4 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by blending method: S301, the polyester chips in S203 are vacuum melted at 250°C, and the polyacrylic acid-coated tourmaline composite particles in S104 are added in a mass ratio of 99:5, and then 0.1% of Sb(Ac)3 is added to the total amount of the system, and mechanical stirring is performed and the reaction is carried out for 12 minutes to obtain molten negative ion fibers; S302. The volume flow rate is accurately measured by a metering pump to be 50-100 cm³ / min. The molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded through a 0.2-0.4 mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120°C, heated to 150°C, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

[0022] Example 5: A method for preparing a negative ion-coated artificial fiber comprises the following steps: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, and then wet ball mill for 3 hours, filter, and dry to obtain tourmaline powder; S102, using concentrated nitric acid and the tourmaline powder in S101 in a mass ratio of 4:1 at room temperature for 1 hour, washing with clean water, filtering, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 30 minutes, raising the temperature to 70° C., and dropwise adding 20% ​​by mass concentration of acrylic acid monomer and 40:5 by mass ratio of potassium persulfate aqueous solution into the reactor, respectively. Keep the temperature at 75° C. for reaction for 3 hours, and cool to room temperature to obtain a polyacrylic acid product; S104, adding the tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 60° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid (2% by weight of the polyacrylic acid), and molecular sieves of the same weight as the polyacrylic acid in S103, wherein the ratio of polyacrylic acid to modified tourmaline powder is 1:8, reacting for 3 h with mechanical stirring, and vacuum filtering and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.5 are reacted at 220° C. until the water output is stable and exceeds 90% of the theoretical amount, and the reaction is continued for 20 minutes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.03% Sb2O3 and 0.02% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for 4 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by blending method: S301, the polyester chips in S203 were vacuum melted at 250°C, and the polyacrylic acid-coated tourmaline composite particles in S104 were added in a mass ratio of 97:3, and then 0.1% of Sb(Ac)3 was added to the total amount of the system, and mechanical stirring was performed and the reaction was carried out for 12 minutes to obtain molten negative ion fibers; S302. The volume flow rate is accurately measured by a metering pump to be 50-100 cm³ / min. The molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded through a 0.2-0.4 mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120°C, heated to 150°C, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

[0023] Comparative Example 1: A method for preparing a negative ion-coated artificial fiber comprises the following steps: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, filter, and dry to obtain tourmaline powder; S102, using concentrated nitric acid and the tourmaline powder in S101 in a mass ratio of 4:1 at room temperature for 1 hour, washing with clean water, filtering, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 30 minutes, raising the temperature to 70° C., and dropwise adding 20% ​​by mass concentration of acrylic acid monomer and 40:5 by mass ratio of potassium persulfate aqueous solution into the reactor, respectively. Keep the temperature at 75° C. for reaction for 3 hours, and cool to room temperature to obtain a polyacrylic acid product; S104, adding the tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 60° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid (2% by weight of the polyacrylic acid), and molecular sieves of the same weight as the polyacrylic acid in S103, wherein the ratio of polyacrylic acid to modified tourmaline powder is 1:8, reacting for 3 h with mechanical stirring, and vacuum filtering and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.5 are reacted at 220° C. until the water output is stable and exceeds 90% of the theoretical amount, and the reaction is continued for 20 minutes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.03% Sb2O3 and 0.02% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for 4 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by blending method: S301, the polyester chips in S203 were vacuum melted at 250°C, and the polyacrylic acid-coated tourmaline composite particles in S104 were added in a mass ratio of 97:3, and then 0.1% of Sb(Ac)3 was added to the total amount of the system, and mechanical stirring was performed and the reaction was carried out for 12 minutes to obtain molten negative ion fibers; S302. The volume flow rate is accurately measured by a metering pump to be 50-100 cm³ / min. The molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded through a 0.2-0.4 mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120°C, heated to 150°C, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

[0024] Comparative Example 2: Compared with Example 5, in Comparative Example 2, polyacrylic acid was added in S104 at one time instead of gradually adding.

[0025] Comparative Example 3: Compared with Example 5, in Comparative Example 3, the molar ratio of phthalic acid to ethylene glycol in S202 is 1:1.

[0026] Comparative Example 4: Compared with Example 5, the ratio of S301 composite particles to polyester chips is 10:90.

[0027] Performance testing: 1. Tourmaline particle size and whiteness detection The tourmaline powder of S102 was tested using a particle size and shape analyzer and a whiteness analyzer.

[0028] 2. Relative strength and elongation at break test Take a 10mm section of finished fiber with uniform thickness, weigh m, and calculate the fiber density N dtex , conduct a tensile test on the fiber, record the tensile force P at break and the lengths l0 and l1 before and after stretching, test 10 groups in parallel and calculate the average value.

[0029] Calculation formula: Fiber density N dtex =l0 / m Relative strength P dtex =P / N dtex Elongation = (l1-l0) / l0×100% 3. Negative ion release test Place 1g of fiber in a transparent sealed box (length, width and height are all 20cm) and let it stand for 1 hour to measure the static negative ion release content. Take another 1g of fiber and rub it by hand 30 times to measure the dynamic negative ion release content.

[0030] Table 1 Performance test data of each group of negative ion fibers Data Analysis: In Example 1, concentrated nitric acid was used to treat the tourmaline powder, but the whiteness was not high. This is because the oxidizing property of concentrated nitric acid may passivate some iron elements, so the color change effect is not as good as concentrated hydrochloric acid. However, more aluminum and iron elements are retained. Combined with the unique polar crystal structure of tourmaline, more negative ions are generated. The data in Table 1 can confirm this. Compared with Example 5, Example 2 increases the ratio of polyacrylic acid to modified tourmaline powder to 1:10. The unstable carboxyl group of polyacrylic acid will undergo esterification reaction with the hydroxyl group on the tourmaline surface at 60°C. Therefore, although the increase in tourmaline content increases the amount of negative ions released, the polyacrylic acid molecules cannot completely cover the tourmaline powder. When subsequently melted with polyester, the tourmaline powder is prone to agglomeration. The binding force here is weak, so the fiber is prone to breakage here, greatly reducing the strength and tensile properties. Compared with Example 5, the mass ratio of the tourmaline composite particles coated with polyacrylic acid and the polyester chips in Example 3 is reduced to 1:99, and the ratio in Example 4 is increased to 5:95. Overall, the more composite particles, the more tourmaline content, and the more negative ions released. Therefore, the negative ion release content of the artificial fiber in Example 5 is greater than that in Example 4 and Example 3, but the tourmaline content is inversely proportional to the mechanical properties. The more composite particles, the higher the tourmaline content, and the agglomeration rate increases. The interfacial bonding force between the composite particles and the polyester is not sufficient to resist the stress transfer during stretching, resulting in the fiber preferentially undergoing brittle fracture at the particle agglomeration point. Therefore, the relative strength and elongation of the artificial fiber in Example 5 are less than those in Example 4 and Example 3.

[0031] Comparative Example 1, compared with Example 5, does not carry out the ball milling step. If not ball milling, the tourmaline particle size is larger, and easily forms hard agglomerates because of the too high surface energy. These large particles or agglomerates can become stress concentration points in the spinning process. When fiber is stretched, stress preferentially assembles in the polyester matrix around the agglomerate, causes matrix premature fracture, and tensile strength significantly reduces. The large-particle tourmaline specific surface area that is not ball milled is little, and the negative ion release content of tourmaline significantly reduces. Comparative Example 2, compared with Example 5, is the disposable adding polyacrylic acid. High concentration polyacrylic acid can be assembled fast because of intermolecular hydrogen bond, preferentially forms too thick coating on part tourmaline particle surface, causes the polyacrylic acid on tourmaline powder surface to be uneven, stress is not concentrated, easily breaks during stretching, and coating the thicker tourmaline powder release negative ion is limited, and the thinner tourmaline powder of coating is exposed to oxidation or wear and tear outside for a long time, and negative ion release amount also can descend. Comparative Example 3, compared with Example 5, adjusts the molar ratio of phthalic acid to ethylene glycol to 1:1. The carboxyl groups and hydroxyl groups react in equal proportions, preventing the formation of hydroxyl-terminated polymers. During subsequent melting, the polymers are physically bound together, without forming esters. This results in weak bonding, reduced tensile properties and strength, and easy detachment of the tourmaline, affecting the long-term negative ion release. Comparative Example 4, compared with Example 5, increases the mass ratio of polyacrylic acid-coated tourmaline composite particles to polyester chips to 10:90. This results in a higher polymer content, resulting in enhanced toughness, excellent strength, and tensile strength of the finished negative ion fiber. However, the negative ion release is relatively low.

[0032] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a negative ion coated artificial fiber, characterized in that: The following steps are involved: S1. Tourmaline powder modification: S101, prepare 1% hydrochloric acid by mass, soak the tourmaline particles for 48 hours, repeatedly wash with clean water, and then wet ball mill for 1-4 hours, filter, and dry to obtain tourmaline powder; S102, using concentrated acid and the tourmaline powder of S101 in a mass ratio of 4:1 and fully stirring and mixing at room temperature for 1-2 hours, filtering, then washing with clean water, and drying to obtain acid-modified tourmaline powder; S103, adding pure water to the reactor, passing nitrogen to deoxygenate for 20-30 minutes, raising the temperature to 70-80° C., adding acrylic acid monomer and potassium persulfate aqueous solution with a mass concentration of 10%-30% dropwise to the reactor, respectively, keeping the temperature at 75° C. for reaction for 2-4 hours, and cooling to room temperature to obtain polyacrylic acid; S104, adding the acid-modified tourmaline powder and pure water in S102 into a reactor, ultrasonically dispersing, and heating to 40-70° C., gradually adding the polyacrylic acid, p-toluenesulfonic acid, and molecular sieves in S103, reacting with mechanical stirring for 2-4 hours, vacuum filtering, and drying to obtain polyacrylic acid-coated tourmaline composite particles; S2. Preparation of polyester fiber: S201, phthalic acid and ethylene glycol in a molar ratio of 1:1.2-1.8 are reacted at 220-240° C. until the water output stabilizes to obtain an esterification product; S202, transfer the esterification product in S201 to a reactor, add 0.02%-0.05% Sb2O3 and 0.01%-0.03% phosphate stabilizer based on the total mass of the system materials, stir evenly, and heat to 280-290°C for reaction for 3-6 hours; S203, cooling the melted S202 polycondensation product and slicing; S3. Preparation of negative ion artificial fiber by solution spinning method: S301, vacuum melting the polyester chips of S203 at 250-280°C, adding the polyacrylic acid-coated tourmaline composite particles of S104 in a mass ratio of 95-99:1-5, and then adding Sb(Ac)3 accounting for 0.01%-0.5% of the total system, mechanically stirring, and reacting for 10-15 minutes to obtain molten negative ion fibers; S302, the volume flow rate is accurately measured by the metering pump to 50-100cm 3 / min, the molten negative ion fiber is distributed to the spinneret through the spinning assembly, extruded from the 0.2-0.4mm spinneret hole to form a continuous filament, pre-stretched to 1.5-2 times the original length, cooled, stretched to 3-4 times the original length at 120-150℃, heated to 150-180℃, maintained for 0.5-1 second, and cooled to obtain the negative ion artificial fiber.

2. The negative ion coated artificial fiber and the preparation method thereof according to claim 1, characterized in that: The ball-to-material ratio of the wet ball milling in S101 is 3-10:1, and the average particle size of the tourmaline powder after ball milling is 2 μm.

3. The method for preparing a negative ion-coated artificial fiber according to claim 1, characterized in that: The concentrated acid in S102 is any one of concentrated hydrochloric acid, concentrated sulfuric acid, and concentrated nitric acid.

4. The method for preparing a negative ion-coated artificial fiber according to claim 1, characterized in that: The mass ratio of pure water, acrylic acid monomer and potassium persulfate aqueous solution in S103 is 50-60:30-45:5-10, and the mass ratio of potassium persulfate to water in the potassium persulfate aqueous solution is 1:

10.

5. The method for preparing a negative ion-coated artificial fiber according to claim 1, characterized in that: The volume of pure water in the S104 is 30-60 mL, the mass ratio of polyacrylic acid to modified tourmaline powder is 1:5-10, and the mass ratio of polyacrylic acid, p-toluenesulfonic acid, and molecular sieve is 1:0.5-3%:1.2-2.

6. The method for preparing a negative ion-coated artificial fiber according to claim 1, characterized in that: The water output in S201 reaches more than 90% of the theoretical value, the esterification rate can exceed 95%, and the reaction is continued for 10-30 minutes.

7. The method for preparing a negative ion-coated artificial fiber according to claim 1, characterized in that: The continuous filaments in S302 have an initial diameter of about 0.5-1.0 mm and shrink to 20-50 μm after cooling.

8. Anion-coated artificial fiber prepared according to the preparation method according to any one of claims 1 to 7.

9. The negative ion-coated artificial fiber according to claim 8 is used in daily clothing and medical fields.

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