Negative ion milk fiber fabric and preparation process

Abstract

The invention relates to the field of textiles, and particularly discloses a negative ion milk fiber fabric and a preparation process. The anion milk fiber fabric is formed by blending anion milk fibers and cotton fibers, wherein the blending ratio of the anion milk fibers to the cotton fibers is (7-7.5): (2.5-3); the anion milk fiber yarns are regenerated protein fibers loaded with nano-scale tourmaline, and the mass ratio of the nano-scale tourmaline in the fiber matrix is 5-15%; the preparation method comprises the following steps: uniformly dispersing the surface-modified nano tourmaline in a milk protein spinning solution, carrying out wet spinning to obtain the negative ion milk fibers, blending the negative ion milk fibers with the cotton fibers to form the fabric, and carrying out plasma treatment. The anion milk fiber fabric has the advantages that the inherent skin-friendly comfort of the milk fibers is kept, and meanwhile, the anion function is permanently and efficiently released.

Description

Technical Field

[0001] This application relates to the field of textiles, and more specifically, to a negative ion milk fiber fabric and its preparation process. Background Technology

[0002] In the high-end apparel fabric sector, regenerated protein fibers, with their skin-friendly properties of natural fibers and the strength and durability of synthetic fibers, have become an important material category to meet consumers' demands for high-quality clothing. Milk fiber is a prime example. This fiber is prepared by graft copolymerization of milk protein and acrylonitrile. Its unique raw material composition and chemical synthesis process allow it to inherit the skin-friendly properties of natural protein fibers while possessing the excellent mechanical strength and durability of synthetic fibers, effectively balancing wearing comfort and fabric lifespan. Therefore, it is widely used in the production and manufacturing of high-end apparel. Currently, the mainstream technical approach in the industry to modify milk fiber fabrics for negative ion functionality involves adding negative ion powder during the fabric's post-processing stage. Specifically, this involves using coating, impregnation, and other processes to attach negative ion powder to the surface of the milk fiber fabric, giving the fabric an initial ability to release negative ions. However, this technical solution has significant limitations and performance defects: First, the negative ion powder and milk fiber only have a superficial physical adhesion relationship, without forming a stable chemical bond or deep fusion structure. During daily wear, friction, and washing with water and detergent, the surface-attached negative ion powder is easily detached, causing the fabric's negative ion release to rapidly decrease with prolonged use, severely affecting the durability of the negative ion function and making it difficult to achieve long-term stable functional output. Second, the surface adhesion of the negative ion powder itself alters the original surface microstructure of the milk fiber fabric. Furthermore, the powder detachment process further damages the inter-fiber void structure, not only making the fabric feel rough and stiff but also hindering air and moisture circulation, significantly reducing the fabric's breathability and ultimately destroying the inherent skin-friendly comfort of the milk fiber fabric, affecting the consumer's wearing experience. In summary, the current technology for preparing negative ion milk fiber fabric based on adding negative ion powder in the post-processing stage presents a contradiction between functional durability and the maintenance of the fabric's basic performance, failing to meet the dual demands of high-end apparel for both functionality and comfort. Summary of the Invention

[0003] To address the aforementioned issues, this application provides a negative ion milk fiber fabric and its preparation process.

[0004] The first part of this application provides a negative ion milk fiber fabric using the following technical solution: A negative ion milk fiber fabric is made by blending negative ion milk fiber filaments and cotton fibers, wherein the blending ratio of negative ion milk fiber filaments to cotton fibers is (7-7.5):(2.5-3); the negative ion milk fiber filaments are regenerated protein fibers loaded with nano-scale tourmaline, and the mass percentage of nano-scale tourmaline in the fiber matrix is ​​5-15%.

[0005] By adopting the above technical solution, a 70%-75% proportion of negative ion milk fiber ensures a sufficient total amount of nano-scale tourmaline in the fiber matrix, providing a material basis for the stable release of negative ions and avoiding the failure of the effect due to insufficient functional components. The 25%-30% cotton fiber compensates for the slight shortcomings of milk fiber in terms of moisture absorption, breathability, and natural softness, while improving the overall flexibility and wrinkle resistance of the fabric, solving the problem of excessive rigidity that may occur with single-milk fiber fabrics. The nano-scale tourmaline is applied "loaded onto the fiber matrix" rather than being attached to the surface through traditional post-processing, structurally eliminating the risk of powder detachment during friction and washing, and completely solving the defect of rapid decay of negative ion function with the usage cycle in the background technology. A mass ratio of 5-15% is the optimal range that has been repeatedly verified, and this ratio can simultaneously take into account functionality and fiber spinnability.

[0006] Optionally, the average particle size of the nano-sized tourmaline is ≤100 nanometers, and the particle size distribution D90 is ≤200 nanometers.

[0007] By adopting the above technical solution, this particle size control can effectively prevent problems such as spinneret clogging, internal fiber stress concentration, and even fiber breakage caused by particle agglomeration, ensuring the continuity of the spinning process and the excellent mechanical properties of the fiber. More importantly, the small particle size provides a huge specific surface area, which allows the fiber to release negative ions more efficiently when subjected to minor environmental stimuli.

[0008] Optionally, the negative ion milk fiber is obtained by wet spinning of a spinning solution containing milk protein, nano-sized tourmaline, dispersant and plasticizer.

[0009] By adopting the above technical solutions, the dispersant can be adsorbed on the surface of nano-tourmaline through steric hindrance effect, preventing the powder from settling or agglomerating in the spinning solution, ensuring the long-term stability of the spinning solution, and avoiding functional breaks in the spun fibers; the plasticizer can penetrate into the molecular chains of milk protein, weaken the intermolecular forces, improve the fluidity of the spinning solution, make the spinning process smoother, increase the flexibility of the fiber after forming, reduce the elongation at break, prevent the fiber from breaking due to excessive rigidity during weaving or wearing, and improve the durability of the fabric.

[0010] Secondly, this application provides a preparation process for negative ion milk fiber fabric.

[0011] A preparation process for a negative ion milk fiber fabric includes the following steps: (a) Surface-modified nano-sized tourmaline was uniformly dispersed in milk protein spinning solution to obtain functionalized spinning solution; (b) The functionalized spinning solution is spun, coagulated, multi-stage drawn and heat-set by wet spinning process to obtain negative ion milk fiber filament. (c) The negative ion milk fiber filaments are blended with cotton fibers to form yarn and woven into fabric, and the resulting fabric is subjected to plasma treatment.

[0012] By adopting the above technical solution and using the in-situ composite technology route, the negative ion functional element is permanently fixed in the internal structure of the fiber during the fiber forming stage, ensuring the durability of the function. At the same time, this process route organically combines material modification, fiber forming, and fabric finishing. In particular, the final low-power short-time plasma treatment can activate only the fabric surface without damaging the fiber body or affecting the internal negative ion material, effectively improving the fabric's hand feel, enhancing its hydrophilicity and dyeing properties, and achieving a synergistic improvement in functionality and wearability.

[0013] Optionally, in step (a), the protein component in the milk protein spinning solution is composed of casein and whey protein in a mass ratio of (3-3.5):(6.52-7), and the pH value of the functionalized spinning solution is adjusted to 6.5-7.0.

[0014] By employing the above technical solutions, casein exhibits good film-forming properties but is relatively hard and brittle, while whey protein is more flexible. This ratio range can synergistically regulate the rheological properties of the spinning solution and the mechanical properties of the final fiber, enabling the fiber to possess both sufficient strength and excellent flexibility. Strictly controlling the pH within the near-neutral, weakly acidic to neutral range is crucial to prevent excessive denaturation, gelation, or precipitation of the protein during subsequent processing and storage, thereby ensuring good stability and spinnability of the spinning solution.

[0015] Optionally, in step (a), the surface modification treatment of the nano-scale tourmaline includes: treating it with a silane coupling agent under ultrasonic assistance; during the preparation of the functionalized spinning solution, polyethylene glycol is added as a dispersant and glycerol as a plasticizer.

[0016] By employing the above technical solutions, silane coupling agent treatment can introduce organic groups onto the surface of nano-tourmaline, greatly enhancing its interfacial compatibility with the milk protein matrix and making the bond between inorganic nanoparticles and organic polymer chains more robust. Ultrasonic assistance ensures the uniformity and dispersion efficiency of the modification. The addition of polyethylene glycol further prevents nanoparticle re-agglomeration through steric hindrance; the introduction of glycerol effectively plasticizes, improving the fiber's flexibility and stretchability. These three factors work together to achieve long-term stable and uniform dispersion of nanomaterials in a polymer system, ultimately resulting in high-performance functional fibers.

[0017] Optionally, in step (b), the wet spinning process specifically involves: extruding the functionalized spinning solution through a spinneret with an aperture of 0.05-0.1 mm and solidifying it in a sodium sulfate coagulation bath with a concentration of 10-15 wt%; the multi-stage drawing includes: a first drawing with a drawing ratio of 2-3 times at 50-60°C, followed by a second drawing with a drawing ratio of 1.5-2 times at 80-90°C after washing; and the heat setting treatment is performed at 100-110°C for 1-2 minutes.

[0018] By adopting the above technical solution, fine denier fibers can be spun with a spinneret orifice diameter of 0.05-0.1mm. Fabrics made from fine denier fibers are more delicate and soft, and have a larger specific surface area, which is conducive to the release of negative ions. If the orifice diameter is too large, the fibers will be too coarse, and the fabric will feel rough. A sodium sulfate coagulation bath concentration of 10-15wt% is the optimal choice. If the concentration is too low, the coagulation speed will be slow and the fibers will easily stick together; if the concentration is too high, the coagulation will be too fast, forming a porous and loose structure inside the fiber, which will reduce the mechanical strength. This concentration allows the spinning solution to coagulate quickly and uniformly after extrusion, forming a dense fiber structure. The low-temperature first draft initially guides the orientation of macromolecular chains, laying the foundation for fiber strength; the intermediate water wash thoroughly removes residual solvents and salts, avoiding corrosion and yellowing of the fibers; the high-temperature second draft further promotes the rearrangement, crystallization, and orientation of macromolecular chains, thereby significantly improving the fiber's breaking strength, modulus, and dimensional stability. The final heat setting treatment eliminates the internal stress of the fiber, locks in excellent morphology and performance, and ensures the stability of the fiber's subsequent processing and the finished fabric.

[0019] Optionally, in step (c), the plasma treatment conditions are: treatment at a power of 300W for 5-10 seconds.

[0020] By employing the aforementioned technical solution, and through the bombardment and activation effect of high-energy particles in plasma, physical etching and chemical modification can be performed only on the outermost layer of the fabric to a depth of a few nanometers without damaging the fiber itself or its internal functional structure. This not only removes the slight oil stains adhering to the fiber surface during spinning and weaving, but also introduces polar groups, thereby significantly improving the fabric's hydrophilicity, antistatic properties, and dye adhesion, ultimately giving the finished fabric a crisper and softer feel and more vibrant and lasting colorfastness.

[0021] In summary, this application has the following beneficial effects: 1. Because this application fundamentally solves the problem of easy detachment of functional components in traditional finishing technology by in-situ composite of nano-tourmaline into the fiber during the spinning stage, and combines its surface modification and fine dispersion technology, it achieves the durability and washability of negative ion function, and ensures the functional life of the product.

[0022] 2. In this application, the optimal blending of milk fiber and cotton fiber, as well as the scientific ratio of protein components in the spinning solution and the use of plasticizers, successfully retain the skin-friendly and soft properties of milk fiber while introducing negative ion function, and also have the breathability and toughness of cotton fiber, thus achieving a high level of unity between functionality and wearing comfort.

[0023] 3. The method of this application ensures the stability of the nanocomposite spinning solution, the spinnability of the fiber, and the mechanical properties by optimizing the parameters of the entire process from spinning solution preparation, wet spinning to fabric finishing. Detailed Implementation

[0024] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources. Example

[0025] Example 1 A preparation process for a negative ion milk fiber fabric: The raw materials are prepared as follows in this embodiment: Negative ion material: Nanoscale tourmaline powder with an initial particle size of approximately 150 nanometers and a purity of >98%.

[0026] Milk proteins: food-grade casein and whey protein.

[0027] Chemical reagents: silane coupling agent (KH-550), polyethylene glycol (PEG-4000), glycerol, sodium hydroxide (NaOH), and sodium sulfate (Na2SO4), all of which are industrial grade.

[0028] Fiber raw material: cotton fiber (specification: 1.5D×38mm).

[0029] Solvent: Deionized water.

[0030] S1: Refinement and Surface Modification of Negative Ion Materials 100 grams of nano-tourmaline powder was placed in a planetary ball mill and ground at 250 rpm for 3 hours. After grinding, a sample was taken and measured by a laser particle size analyzer. The average particle size was 85 nanometers and the D90 was 180 nanometers.

[0031] The ground tourmaline powder was dispersed in deionized water, and 1.0 wt% of silane coupling agent KH-550 was added.

[0032] The mixture was placed in an ultrasonic disperser and ultrasonically treated for 10 minutes at a power of 600W to obtain a surface-modified and uniformly dispersed negative ion material slurry for later use.

[0033] S2: Prepare milk protein spinning solution A 3 wt% NaOH solution is prepared in a reaction vessel.

[0034] Weigh out the mixed protein according to the mass ratio of casein:whey protein = 3.2:6.8, and slowly add it to the alkaline solution while stirring.

[0035] Heat the system to 70°C and stir continuously until the protein is completely dissolved.

[0036] The pH of the solution was carefully adjusted to 6.8 with dilute hydrochloric acid to obtain a milk protein spinning solution with a solid content of approximately 12 wt%.

[0037] S3: Preparation of Functionalized Spinning Solution Add the negative ion material slurry obtained in S1 (10 wt% of the total mass of the spinning solution by dry weight) to the milk protein spinning solution prepared in S2.

[0038] First, mix the ingredients in a mixer at 800 rpm for 45 minutes to achieve initial mixing.

[0039] Subsequently, 2 wt% polyethylene glycol (PEG-4000) as a dispersant and 4 wt% glycerol as a plasticizer were added to the spinning solution.

[0040] Increase the mixer speed to 1200 rpm and continue stirring for 2 hours until the mixture is uniform and stable with no visible particles or agglomerates, thus obtaining the functionalized spinning solution.

[0041] S4: Spinning and forming to prepare negative ion milk fiber filaments S4-1 Coagulation and Molding: The functionalized spinning solution is pumped at a flow rate of 65 mL / min through a spinneret with a diameter of 0.08 mm and 40 holes, and extruded into a sodium sulfate coagulation bath with a temperature of 35℃ and a concentration of 12 wt%, and solidified into nascent fiber filaments.

[0042] S4-2 First Drafting and Washing: The nascent fibers are first drafted in a 55°C warm water bath with a draft ratio of 2.5. Subsequently, they are passed through multiple washing tanks to thoroughly wash away any residual solvents and salts on the fibers.

[0043] S4-3 Second Drafting: The washed fibers are subjected to a second drafting process in a steam environment at 85℃, with a drafting ratio of 1.8.

[0044] S4-4 Heat Setting: Finally, the fiber filaments are placed in a hot air oven at 105℃ for 1.5 minutes to complete the heat setting and obtain stable negative ion milk fiber filaments.

[0045] S5: Textile forming and fabric preparation The obtained negative ion milk fiber filaments were blended with cotton fiber at an actual blending ratio of 72:28. The yarn underwent sequential processes including opening, carding, drawing, roving, and spinning to produce a 40-count blended yarn. This yarn was then woven into a plain weave fabric using a rapier loom. The woven fabric was then treated with a low-temperature plasma treatment device at 300W for 8 seconds to obtain the final negative ion milk fiber fabric.

[0046] Example 2 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (c) textile forming, the blending ratio of negative ion milk fiber and cotton fiber is adjusted to 75:25.

[0047] Example 3 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (c) textile forming, the blending ratio of negative ion milk fiber and cotton fiber is adjusted to 70:30.

[0048] Example 4 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (a) the negative ion material pretreatment, the ball milling process is controlled so that the average particle size of the nano-tourmaline is 95 nanometers and the particle size distribution D90 is 195 nanometers.

[0049] Example 5 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (a) of preparing the milk protein spinning solution, the mass ratio of casein to whey protein is adjusted to 3.5:6.5.

[0050] Example 6 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (a) of preparing the functionalized spinning solution, the amount of pretreated negative ion material added accounts for 5 wt% of the total mass of the spinning solution.

[0051] Example 7 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (a) of preparing the functionalized spinning solution, the amount of pretreated negative ion material added accounts for 15 wt% of the total mass of the spinning solution.

[0052] Example 8 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (b), the first stretching ratio is adjusted to 2.0 times and the temperature is 60°C.

[0053] Example 9 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (c), the plasma treatment time is 5 seconds.

[0054] Comparative Example Comparative Example 1 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that, instead of blending and modifying the spinning solution, a negative ion material is added through a post-treatment process. Specifically: First, ordinary milk fiber filaments without nano-tourmaline were prepared according to the method in Example 1.

[0055] Then, the milk fiber filaments are blended with cotton fibers in the same ratio of 72:28 to create a fabric.

[0056] Finally, the fabric is immersed in a finishing solution containing 10wt% nano tourmaline powder, 2wt% binder (polyurethane) and 1wt% dispersant, using a two-dip and two-nip process, and then dried and set at 120°C to obtain the fabric.

[0057] Comparative Example 2 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that in step (c) textile forming, the blending ratio of negative ion milk fiber and cotton fiber is adjusted to 60:40.

[0058] Comparative Example 3 A preparation process for a negative ion milk fiber fabric: The difference from Example 1 is that the surface modification treatment in step (a) is omitted (without adding silane coupling agent and ultrasound), and tourmaline powder with an initial particle size of 150 nanometers is directly added to the spinning solution in step (a).

[0059] Performance testing Negative ion release: According to the standard GB / T30128-2013 "Detection and Evaluation of Negative Ion Generation in Textiles", the test was conducted using an atmospheric ion meter under standard temperature and humidity conditions (temperature 20±2℃, humidity 50±5%). The initial value and the value after washing were recorded.

[0060] Wash resistance: The samples were washed according to procedure 5A of the standard GB / T8629-2017 Textiles - Test Procedures for Household Washing and Drying. After washing, the samples were conditioned under standard conditions and then tested.

[0061] Mechanical properties (breaking strength): Tested according to the standard GB / T3923.1-2013 Textiles - Tensile properties of fabrics - Part 1: Determination of breaking strength and elongation at break (strip method)

[0062] Air permeability: Tested according to the standard GB / T5453-1997 Determination of air permeability of textile fabrics.

[0063] Spinability evaluation: During the spinning process, the frequency of spinneret clogging and fiber breakage rate are observed and recorded, and are divided into three levels: "excellent", "good" and "poor".

[0064] Table 1 Detection Data As can be seen from Example 1 and Comparative Example 1, and Table 1, the fabric prepared using the in-situ loading technology described in this invention (Example 1) retains up to 87% of its negative ion release rate after 50 washes, while the Comparative Example 1, which uses a traditional finishing process, retains only 32.7% and has significantly reduced breathability. This fully demonstrates that this invention fundamentally solves the problem of functional durability through fiber internal loading technology and effectively maintains the comfort of wearing the fabric.

[0065] Combining Example 1 and Comparative Example 2 with Table 1, it can be seen that when the proportion of cotton fibers exceeds the protection scope of this invention (Comparative Example 2), although the breathability of the fabric is improved, its negative ion release (1650 ions / cm³) is still low. 3 The values ​​were significantly lower than those in Example 1 (2850 ions / cm). 3This fails to meet the requirements of functional fabrics, which confirms the necessity of the blending ratio specified in claim 1 for balancing functionality and comfort.

[0066] Combining Example 1 and Comparative Example 3 with Table 1, it can be seen that Comparative Example 3 failed to perform the spinning process due to the omission of the surface modification treatment of nano-tourmaline (spinnability was rated as "poor"). This proves that the surface modification treatment described in claim 6 is an indispensable key step in realizing the technical solution of the present invention.

[0067] As can be seen from Examples 1-3 and Table 1, within the blending ratio range defined in claim 1, as the proportion of milk fiber increases (Example 3→1→2), the amount of negative ions released by the fabric increases accordingly, while the breathability decreases slightly. This proves that the present invention can flexibly adjust the functionality and comfort of the fabric according to needs by precisely controlling the blending ratio.

[0068] Combining Examples 1 and 4 with Table 1, it can be seen that when the nano-tourmaline particle size is close to the upper limit of claim 2 (Example 4), its negative ion release and fiber strength are slightly lower than those of Example 1. This indicates that controlling the particle size within the preferred range helps to obtain better overall performance.

[0069] Combining Examples 1 and 5 with Table 1, it can be seen that appropriately increasing the casein ratio (Example 5) can increase the fiber breaking strength by about 7.7%, proving that the mechanical properties of fibers can be effectively controlled by adjusting the ratio of casein to whey protein.

[0070] Combining Examples 1, 6-7 and Table 1, it can be seen that the amount of negative ion material added directly affects the functionality and spinnability of the fabric: too low an addition (Example 6) results in insufficient functionality; too high an addition (Example 7) although it has the strongest functionality, it sacrifices mechanical properties and spinnability; the 10wt% addition in Example 1 achieves the best balance between functionality and spinnability.

[0071] As can be seen from Examples 1 and 8 and Table 1, reducing the first draft ratio (Example 8) results in a significant decrease in fiber breaking strength of approximately 11.5%, demonstrating that the drafting process defined in claim 7 is crucial to ensuring fiber mechanical properties.

[0072] Combining Examples 1 and 9 with Table 1, it can be seen that after shortening the plasma treatment time from 8 seconds to 5 seconds, the negative ion release performance and mechanical properties of the resulting fabric (Example 9) did not show a significant decrease compared to Example 1, and its negative ion release and tensile strength remained at excellent levels. This proves that plasma treatment can effectively function within the treatment time range (5-10 seconds) defined in claim 8. Simultaneously, this result also indicates that the plasma treatment, as a mild surface modification technique, mainly acts on the fabric surface and does not damage the fiber structure or the internal negative ion functional components, thereby improving the fabric surface properties while ensuring functional durability and physical integrity.

[0073] As can be seen from Examples 1-9 and Table 1, all examples successfully prepared fabrics with good negative ion function, and the various performance indicators were excellent. This proves that the entire process route provided by the present invention has wide implementability and reliability, and qualified functional fabrics can be obtained by adjusting each process parameter within the scope of the claims.

[0074] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A negative ion milk fiber fabric, characterized in that, The negative ion milk fiber and cotton fiber are mixed to form a yarn, wherein the mixing ratio of the negative ion milk fiber and the cotton fiber is (7-7.5):(2.5-3); the negative ion milk fiber is a regenerated protein fiber loaded with nano tourmaline, and the mass fraction of the nano tourmaline in the fiber matrix is 5-15%.

2. The anionized milk fiber fabric according to claim 1, characterized in that, The average particle size of the nano tourmaline is ≤100 nm, and the particle size distribution D90 is ≤200 nm.

3. The anionized milk fiber fabric according to claim 1, characterized in that, The negative ion milk fiber is prepared by wet spinning of a spinning solution containing milk protein, nano tourmaline, dispersant and plasticizer.

4. A process for the production of a negative ion milk fiber fabric as claimed in any one of claims 1 to 3, characterized in that, The method comprises the following steps: (a) uniformly dispersing the surface-modified nano tourmaline in a milk protein spinning solution to obtain a functionalized spinning solution; (b) spinning, coagulating, multi-stage drawing and heat setting the functionalized spinning solution by a wet spinning process to obtain the negative ion milk fiber; (c) mixing the negative ion milk fiber and cotton fiber to form a yarn and weaving the yarn into a fabric, and then performing plasma treatment on the fabric.

5. The process for preparing the anion milk fiber fabric according to claim 4, characterized in that, In step (a), the protein component in the milk protein spinning solution is composed of casein and whey protein at a mass ratio of (3-3.5):(6.52-7), and the pH value of the functionalized spinning solution is adjusted to 6.5-7.

0.

6. The process for preparing the negative ion milk fiber fabric as claimed in claim 4, wherein, In step (a), the surface modification treatment of the nano tourmaline includes using a silane coupling agent to treat the nano tourmaline under ultrasonic assistance; and in the preparation process of the functionalized spinning solution, polyethylene glycol is added as a dispersant, and glycerol is added as a plasticizer.

7. The process for preparing the negative ion milk fiber fabric according to claim 4, characterized in that, In step (b), the wet spinning process is as follows: the functionalized spinning solution is extruded through a spinneret with a pore size of 0.05-0.1 mm and then enters a sodium sulfate coagulation bath with a concentration of 10-15 wt% for solidification; the multi-stage drawing includes first-stage drawing at 50-60°C with a draw ratio of 2-3 times, and after washing, second-stage drawing at 80-90°C with a draw ratio of 1.5-2 times; and the heat setting treatment is performed at 100-110°C for 1-2 minutes.

8. The process for preparing the negative ion milk fiber fabric as claimed in claim 4, wherein, In step (c), the plasma treatment is performed at a power of 300 W for 5-10 seconds.

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