In-situ ion-exchange modified nonwoven fabric and method for preparing the same

Abstract

The present application relates to the technical field of non-woven fabrics, and particularly relates to an in-situ ion replacement modified non-woven fabric and a preparation method thereof.The present application comprises the following steps: dipping a pretreated non-woven fabric substrate into a sodium alginate solution, vacuum treatment, liquid rolling and drying to obtain a semi-dry state non-woven fabric loaded with sodium alginate; immersing the obtained semi-dry state non-woven fabric into a calcium lactate aqueous solution and a calcium chloride aqueous solution in sequence to carry out an ion replacement reaction, and obtaining a water-containing state calcium alginate modified non-woven fabric; immersing the obtained water-containing state calcium alginate modified non-woven fabric into a mineralization induction liquid A and a mineralization fixing liquid B in sequence to carry out a mineralization treatment, and then washing, drying, and obtaining the same; wherein the mineralization induction liquid A contains a phosphorus source and a silicon source, and the mineralization fixing liquid B contains a zinc source, a calcium source, a strontium source and lactoferrin peptide.The non-woven fabric obtained by the present application has good antibacterial performance, functional layer fixing stability and skin repair auxiliary effect.

Description

Technical Field

[0001] This invention relates to the field of nonwoven fabric technology, specifically to an in-situ ion-displacement modified nonwoven fabric and its preparation method. Background Technology

[0002] Nonwoven fabrics, due to their lightweight, softness, breathability, high processing efficiency, and suitability for large-scale continuous production, are widely used in hygiene care, medical dressings, skin contact materials, mask base fabrics, and functional wiping materials. With the continuous expansion of application scenarios, ordinary nonwoven fabrics are no longer required to only possess basic functions such as liquid absorption, covering, or support; they also need to further exhibit comprehensive properties such as antibacterial properties, skin-friendliness, moisture stability, and stable retention of functional components. Especially in applications involving direct contact with human skin, nonwoven materials not only need to maintain softness and a close fit to the skin and good liquid conductivity, but also need to reduce the risk of bacterial growth and maintain good structural integrity and functional stability in humid environments.

[0003] Alginate materials are a class of polysaccharide materials derived from natural seaweed. Their molecular chains contain numerous carboxyl and hydroxyl groups, exhibiting excellent hydrophilicity, biocompatibility, and gel-forming ability. Sodium alginate can undergo ionic cross-linking with calcium ions to form an insoluble calcium alginate gel network, thus it is frequently used in the preparation of absorbent materials, wet dressings, gel carriers, and skin-contact functional materials. Introducing alginate into nonwoven fabric systems can improve the absorbency and wet integrity of nonwoven fabrics to a certain extent. In particular, introducing sodium alginate into pre-formed nonwoven fabrics through post-treatment, followed by calcium ion replacement to generate a calcium alginate network, avoids the impact of pre-spinning blending or pre-web forming modification on fiber processing, demonstrating good process adaptability.

[0004] However, existing in-situ ion-exchange modified nonwoven fabrics still have certain shortcomings. First, the simply formed calcium alginate network mainly serves as a hydrophilic absorbent and gel support, with a relatively simple functional layer structure, offering limited contribution to antibacterial and repair functions. Second, if antibacterial agents, repair agents, or functional ions are directly impregnated, sprayed, or coated onto the surface of the nonwoven fabric, the functional components mostly adhere through physical adsorption or weak interactions, making them prone to migration and detachment during washing, soaking, or use, resulting in insufficient function retention. Third, when inorganic salt deposition or mineralization is performed directly on the surface of the nonwoven fabric, the reactants are prone to free precipitation in the treatment solution or the formation of coarse, uneven particle deposition layers on the fiber surface, which not only affects the stability of functional component fixation but may also reduce the softness, skin-friendliness, and comfort of the nonwoven fabric.

[0005] Therefore, how to construct a modified structure in an existing nonwoven fabric that can maintain the original softness and liquid absorption of the nonwoven fabric, while also stably supporting functional components such as antibacterial and repair properties, is a problem that needs to be solved in the current modification of functional nonwoven fabrics. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides an in-situ ion-displacement modified nonwoven fabric and its preparation method.

[0007] Existing nonwoven fabrics modified using in-situ ion exchange typically involve introducing sodium alginate into the nonwoven fabric or fiber system, followed by calcium ion exchange to form a calcium alginate structure. While this method can improve the hydrophilicity and wet integrity of the nonwoven fabric to some extent, the resulting calcium alginate layer is mostly a single gel network with a relatively simple functional layer structure, limiting its capacity to carry antibacterial components, repair components, or functional ions. If zinc salts, peptides, or other functional additives are subsequently directly impregnated into the nonwoven fabric, the functional components mainly adhere to the fiber surface through physical adsorption or weak interactions, making them prone to migration and loss during washing, soaking, or use, hindering the formation of a stable functional retention effect. Furthermore, direct inorganic salt deposition or simple mineralization treatment can easily lead to free precipitation in the treatment solution or the formation of coarse particles on the fiber surface, resulting in uneven distribution and weak bonding of the deposited layer, affecting the softness, skin-friendliness, and stability of the nonwoven fabric.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A method for preparing an in-situ ion-displacement modified nonwoven fabric includes the following steps: S1. Clean and dry the non-woven fabric substrate to obtain a pretreated non-woven fabric substrate; S2. The pretreated nonwoven fabric substrate is impregnated with sodium alginate solution, and then subjected to vacuum treatment, squeezing and drying to obtain a semi-dry nonwoven fabric loaded with sodium alginate, with its moisture content controlled at 20%-40%. S3. The semi-dry nonwoven fabric obtained in step S2 is sequentially immersed in calcium lactate aqueous solution and calcium chloride aqueous solution to carry out ion exchange reaction, and then aqueous calcium alginate modified nonwoven fabric is obtained. S4. The aqueous calcium alginate modified nonwoven fabric obtained in step S3 is sequentially immersed in mineralization induction solution A and mineralization fixation solution B for mineralization treatment, and then washed and dried to obtain the final product. The mineralization induction solution A contains a phosphorus source and a silicon source, and the mineralization fixation solution B contains a zinc source, a calcium source, a strontium source, and lactoferrin peptide.

[0009] This invention first uses vacuum impregnation and semi-dry control to allow sodium alginate to fully penetrate the fiber gaps and pore structure of the formed nonwoven fabric. Then, a two-step ion exchange process using calcium lactate and calcium chloride is employed to generate a calcium alginate network in situ within the nonwoven fabric. This calcium alginate network not only exists as a hydrophilic gel structure but also serves as the calcium source basis, confined reaction space, and binding site for subsequent mineralization reactions. Next, the fabric is treated sequentially with mineralization induction solution A and mineralization fixation solution B. Under the regulation of sodium γ-polyglutamate and sodium phytate, the phosphorus and silicon sources in mineralization induction solution A preferentially form a relatively uniform calcium-phosphorus / silicon mineralization precursor layer near the calcium alginate network. Zinc ions, calcium ions, strontium ions, and lactoferrin peptides in mineralization fixation solution B then coordinate, deposit, intercalate, and are fixed at multiple points with this precursor layer, thereby forming a relatively stable composite mineralization functional layer on the surface of the nonwoven fabric fibers and within its pores.

[0010] Preferably, the mass concentration of the sodium alginate solution in step S2 is 1%-3%; the vacuum degree of the vacuum treatment is -0.05MPa to -0.1MPa, and the treatment time is 1-10min; the drying is hot air drying at a temperature of 40-60℃ until the moisture content is 25%-35%.

[0011] Preferably, in step S3, the mass concentration of the calcium lactate aqueous solution is 0.5%-2%, the pH is 6.5-7.0, and the treatment time is 1-5 min; the mass concentration of the calcium chloride aqueous solution is 1%-2%, and the treatment time is 3-10 min; the treatment temperature is 20-30℃.

[0012] Preferably, in step S3, after the ion exchange treatment, there is also a washing and rolling step to control the liquid carryover rate to 100%-150%.

[0013] Sodium glycerophosphate and sodium dihydrogen phosphate in mineralization induction solution A act as phosphate donors, diffusing into the interfiber gaps and pores of the aqueous calcium alginate-modified nonwoven fabric. They interact locally with exchangeable calcium ions and carboxyl groups in the calcium alginate network, forming a calcium-phosphorus precursor layer on the nonwoven fabric fiber surface and at fiber cross-pores. Sodium silicate provides silicate ions that participate in the calcium-phosphorus deposition process, resulting in a silicon-containing, low-crystallinity calcium-phosphorus structure in the mineralized layer. Sodium γ-polyglutamate and sodium phytate regulate the calcium-phosphorus deposition rate, inhibiting the rapid free precipitation or coarsening of calcium phosphate particles in the treatment solution, thus preferentially causing the mineralization reaction to occur near the calcium alginate network. Therefore, the calcium alginate network not only exists as the object of modification but also serves as a confined template, calcium source, and binding site for the mineralization reaction, participating in the formation of the subsequent mineralized layer.

[0014] Preferably, the mineralization induction solution A comprises the following components in parts by weight: 10-30 parts by weight of sodium glycerophosphate, 1-5 parts by weight of sodium dihydrogen phosphate, 0.5-3 parts by weight of sodium γ-polyglutamate, 0.5-2 parts by weight of sodium silicate, 0.5-3 parts by weight of sodium phytate, and 4000-6000 parts by weight of water. After stirring and dissolving, the pH value is adjusted to 5.5-6.5 with lactic acid to obtain the solution.

[0015] Zinc gluconate, calcium chloride, and strontium lactate in mineralization fixation solution B further coordinate, deposit, and intercalate with the aforementioned calcium phosphate / silicon precursor layer, causing zinc and strontium ions to bind in the low-crystallinity calcium phosphate mineralization layer. Simultaneously, lactoferrin peptides, through their carboxyl, amino, and amide groups, undergo coordination adsorption, hydrogen bonding, and multi-point fixation with calcium, zinc, and strontium ions and the surface of the mineralization layer, thus being stably loaded onto the surface and pores of the nonwoven fabric fibers. The resulting mineralization functional layer is not a pre-prepared inorganic powder layer coated onto the nonwoven fabric surface, nor is it a simple impregnation and adsorption layer of antibacterial or repairing agents. Instead, it is a low-crystallinity calcium phosphate mineralization composite layer containing zinc, strontium, and silicon, formed based on an in-situ generated calcium alginate network. This improves the fixation stability of the functional components and gives the nonwoven fabric better antibacterial properties and skin repair auxiliary effects.

[0016] Preferably, the mineralization fixative B comprises the following components in parts by weight: 8-16 parts by weight of zinc gluconate, 3-8 parts by weight of calcium chloride, 1-4 parts by weight of strontium lactate, 4-8 parts by weight of lactoferrin peptide and 6000-10000 parts by weight of water, stirred and dissolved, and then the pH value is adjusted to 6.5-7.0 with lactic acid to obtain the final product.

[0017] Preferably, the temperature of the mineralization treatment in step S4 is 25-35℃, the treatment time in the mineralization induction solution A is 5-10 min, and the treatment time in the mineralization fixation solution B is 8-15 min; the drying after treatment is hot air drying at a temperature of 40-50℃ until the moisture content is 5%-15%.

[0018] This invention enables the construction of a functional layer that is more tightly integrated with the fiber pore structure without altering the basic sheet-like morphology of the nonwoven fabric. In this functional layer, the calcium alginate network provides the basis for in-situ molding and confined fixation; the calcium phosphorus / silicon mineralization layer enhances the binding stability of functional ions; zinc ions and lactoferrin peptides jointly impart antibacterial effects; and strontium ions, silicon sources, and lactoferrin peptides help improve the repair and auxiliary properties of the material when in contact with the skin. Compared to schemes that only form a calcium alginate network, only employ mineralization induction treatment, only employ mineralization fixation treatment, or lack key regulatory components, this invention, through continuous processing of in-situ construction of the calcium alginate network, formation of a controlled mineralization precursor layer, and fixation of functional ions and lactoferrin peptides, ensures that the functional components are no longer merely impregnated on the surface but are stably bound within the nonwoven fabric and the surface mineralization layer. Therefore, it achieves better antibacterial properties, functional retention, and skin repair auxiliary effects.

[0019] An in-situ ion-displacement modified nonwoven fabric, the nonwoven fabric comprising a nonwoven fabric substrate and a calcium alginate network structure generated in-situ on and inside the surface of the nonwoven fabric substrate, wherein a low-crystallinity calcium phosphate mineralization deposit layer is loaded on the calcium alginate network structure, the low-crystallinity calcium phosphate mineralization deposit layer comprising calcium, phosphorus, silicon, zinc and strontium.

[0020] Preferably, the mineralized deposit layer further comprises lactoferrin peptides.

[0021] The beneficial effects of this invention are: This invention provides an in-situ ion-replacement modified nonwoven fabric and its preparation method. By post-loading sodium alginate onto a pre-formed nonwoven substrate and performing stepwise ion replacement with calcium lactate and calcium chloride, an in-situ calcium alginate network is formed on the surface of the nonwoven fibers and within the pores between the fibers. Compared to directly forming a web using alginate fibers or simply impregnating functional additives onto the surface of the nonwoven fabric, this invention can form a calcium alginate network layer that is tightly integrated with the pore structure of the nonwoven fabric while maintaining its original sheet-like structure, softness, and usability. This provides a calcium source, carboxyl binding sites, and confined reaction space for the stable fixation of subsequent functional components, thereby improving the structural stability of the modified nonwoven layer.

[0022] This invention further utilizes continuous treatment with mineralization induction solution A and mineralization fixation solution B to form a low-crystallinity mineralization composite layer containing calcium, phosphorus, silicon, zinc, and strontium on a calcium alginate network, and stably loads lactoferrin peptides into this mineralization layer. The phosphorus and silicon sources in mineralization induction solution A can form a calcium-phosphorus / silicon mineralization precursor layer near the calcium alginate network, while sodium γ-polyglutamate and sodium phytate can regulate the mineralization deposition process, reducing the formation of free precipitates and coarse particles. Zinc ions, strontium ions, and lactoferrin peptides in mineralization fixation solution B are further fixed in the mineralization layer through deposition, coordination, hydrogen bonding, and multi-site adsorption. Therefore, this invention does not simply rely on the surface adsorption of antibacterial agents or repair agents, but achieves stable binding of functional components through an in-situ mineralization composite layer, which is beneficial for improving the retention rate of functional components and stability during use.

[0023] The in-situ ion-replacement modified nonwoven fabric obtained by this invention exhibits good antibacterial properties, antibacterial retention, and skin repair auxiliary properties. Zinc ions and lactoferrin peptides work together to enhance the inhibitory effect of the nonwoven fabric on common bacteria; strontium ions, silicates, and lactoferrin peptides collectively improve the material microenvironment when the nonwoven fabric comes into contact with the skin, helping to promote the migration of skin repair-related cells; simultaneously, the mineralization layer, relying on a calcium alginate network, is formed and fixed on the fiber surface and inside the pores, allowing the nonwoven fabric to maintain good functional stability even after washing or soaking. Detailed Implementation

[0024] The invention will now be described in further detail with reference to specific embodiments, but it should not be construed as limiting the scope of the invention to the following embodiments.

[0025] This application describes some of the raw materials; all other raw materials not described are commercially available. The nonwoven fabric substrate is spunlace nonwoven fabric, purchased from Kaimaoxing (Hebei) Cellulose Co., Ltd., with a basis weight of 30-60 g / m². 2 .

[0026] Sodium alginate was purchased from Shandong Duoju Chemical Co., Ltd.

[0027] Sodium γ-polyglutamate was purchased from Guangzhou Aiante Biotechnology Co., Ltd., product number: HH50118PI0XC.

[0028] The lactoferrin peptide was purchased from Shanghai Yingxin Laboratory Equipment Co., Ltd., item number: TX21931-5g.

[0029] Example 1: A method for preparing an in-situ ion-exchange modified nonwoven fabric, comprising the following steps: S1. Cut the non-woven fabric substrate into 20cm×20cm sheets and immerse them in 40℃ water for 10min; then dry them in 60℃ hot air for 20min to obtain the pretreated non-woven fabric substrate. S2. Mix 20 parts by weight of sodium alginate and 980 parts by weight of water, and stir at 45°C and 500 rpm for 1.5 h to obtain a sodium alginate treatment solution. Immerse the pretreated nonwoven fabric substrate obtained in step S1 completely in the sodium alginate treatment solution at a bath ratio of 1:30, maintain it under a vacuum of -0.08 MPa for 5 min, then restore it to normal pressure and continue immersion for 10 min. Take out the nonwoven fabric and perform liquid-pickling treatment through a roller with a pressure of 0.25 MPa and a temperature of 30°C. The liquid content of the nonwoven fabric is 120%. Dry it under hot air at 45°C until the moisture content of the nonwoven fabric is controlled at 30% to obtain a semi-dry nonwoven fabric loaded with sodium alginate. S3. Immerse the semi-dry nonwoven fabric loaded with sodium alginate obtained in step S2 into the calcium lactate aqueous solution at a bath ratio of 1:25 and treat it at 25°C for 3 minutes. Transfer the nonwoven fabric after the initial calcium lactate treatment into a 1.5% (w / w) calcium chloride aqueous solution at a bath ratio of 1:25 and continue to treat it at 25°C for 6 minutes to obtain a nonwoven fabric with an in-situ calcium alginate network structure. Remove the fabric, wash it with water, and lightly roll it through a roller at a pressure of 0.25 MPa and a temperature of 30°C, controlling the liquid content of the nonwoven fabric to be 130%, to obtain an aqueous calcium alginate modified nonwoven fabric. The calcium lactate aqueous solution contains 1 wt% calcium lactate and has a pH of 6.7. S4. Immerse the aqueous calcium alginate modified nonwoven fabric in mineralization induction solution A at a bath ratio of 1:25 and treat it at 30°C for 7 minutes. Then transfer the nonwoven fabric treated with mineralization induction solution A to mineralization fixation solution B at a bath ratio of 1:25 and continue to treat it at 30°C for 10 minutes. Remove the fabric, wash it with water, and then lightly roll it through a roller at a pressure of 0.25 MPa and a temperature of 30°C, controlling the liquid content to 100%. Then dry it under hot air at 45°C until the moisture content of the nonwoven fabric is 10%, thus obtaining the in-situ ion-displacement modified nonwoven fabric.

[0030] The preparation method of the mineralization induction solution A is as follows: Take 20 parts by weight of sodium glycerophosphate, 3 parts by weight of sodium dihydrogen phosphate, 1.5 parts by weight of sodium γ-polyglutamate, 1 part by weight of sodium silicate, 1.5 parts by weight of sodium phytate and 5000 parts by weight of water, stir to dissolve, and adjust the pH value to 6.0 with lactic acid to obtain the solution.

[0031] The mineralization fixative B is prepared as follows: Weigh 12 parts by weight of zinc gluconate, 5 parts by weight of calcium chloride, 2 parts by weight of strontium lactate, 6 parts by weight of lactoferrin peptide and 8000 parts by weight of water, stir to dissolve, and adjust the pH value to 6.7 with lactic acid to obtain the solution.

[0032] Example 2: Basically the same as Example 1, except that in S4, the aqueous calcium alginate modified nonwoven fabric is immersed in mineralization induction solution A and treated at 30°C for 5 min; then it is transferred to mineralization fixation solution B and treated at 30°C for another 12 min.

[0033] Example 3: Basically the same as Example 1, except that in S4, the aqueous calcium alginate modified nonwoven fabric is immersed in mineralization induction solution A and treated at 30°C for 9 min; then it is transferred to mineralization fixation solution B and treated at 30°C for another 8 min.

[0034] Comparative Example 1: It is basically the same as Example 1, except that only S1 pretreatment is performed, and S2, S3 and S4 treatments are not performed, and the pretreated nonwoven fabric substrate is obtained directly.

[0035] Comparative Example 2: Basically the same as Example 1, except that: only S1, S2 and S3 treatments were performed, and S4 mineralization induction liquid A and mineralization fixation liquid B treatments were not performed; the aqueous calcium alginate modified nonwoven fabric was directly dried at 45°C hot air to a moisture content of 10%.

[0036] Comparative Example 3: It is basically the same as Example 1, except that the mineralization induction liquid A treatment step in S4 was not performed. Instead, the aqueous calcium alginate modified nonwoven fabric obtained in S3 was directly immersed in mineralization fixation liquid B and treated at 30°C for 10 min. Then it was washed, squeezed, and dried until the water content was 10%.

[0037] Comparative Example 4: It is basically the same as Example 1, except that the mineralization fixation solution B treatment step in S4 was not performed. Instead, the aqueous calcium alginate modified nonwoven fabric obtained in S3 was directly immersed in the mineralization induction solution A and treated at 30°C for 10 min. Then it was washed, squeezed, and dried until the water content was 10%.

[0038] Comparative Example 5: Basically the same as Example 1, except that: the preparation method of the mineralization induction solution A is as follows: take 20 parts by weight of sodium glycerophosphate, 3 parts by weight of sodium dihydrogen phosphate, 1 part by weight of sodium silicate and 5003 parts by weight of water, stir to dissolve, and adjust the pH value to 6.0 with lactic acid to obtain the solution.

[0039] Comparative Example 6: Basically the same as Example 1, except that: the preparation method of the mineralization induction solution A is as follows: take 20 parts by weight of sodium glycerophosphate, 3 parts by weight of sodium dihydrogen phosphate, 1.5 parts by weight of sodium γ-polyglutamate, 1.5 parts by weight of sodium phytate and 5001 parts by weight of water, stir to dissolve, and adjust the pH value to 6.0 with lactic acid to obtain the solution.

[0040] Comparative Example 7: Basically the same as Example 1, except that: the preparation method of the mineralized fixative B is as follows: weigh 5 parts by weight of calcium chloride, 2 parts by weight of strontium lactate, 6 parts by weight of lactoferrin peptide and 8012 parts by weight of water, stir to dissolve, and adjust the pH value to 6.7 with lactic acid to obtain the solution.

[0041] Comparative Example 8: Basically the same as Example 1, except that: the preparation method of the mineralized fixative B is as follows: weigh 12 parts by weight of zinc gluconate, 5 parts by weight of calcium chloride, 6 parts by weight of lactoferrin peptide and 8002 parts by weight of water, stir to dissolve, and adjust the pH value to 6.7 with lactic acid to obtain the solution.

[0042] Comparative Example 9: Basically the same as Example 1, except that: the preparation method of the mineralized fixative B is as follows: weigh 12 parts by weight of zinc gluconate, 5 parts by weight of calcium chloride, 2 parts by weight of strontium lactate and 8008 parts by weight of water, stir to dissolve, and adjust the pH value to 6.7 with lactic acid to obtain the solution.

[0043] Test Example 1: Antibacterial performance test: The test was conducted in accordance with the national standard GB / T 20944.3-2008 "Evaluation of antibacterial properties of textiles - Part 3: Vibration method".

[0044] Test method: The samples obtained in Examples 1-3 and Comparative Examples 1-9 were cut into approximately 0.75g pieces, placed in sterile Erlenmeyer flasks, and 70mL of phosphate buffer and bacterial suspension of a specified concentration were added to make the initial bacterial concentration 1.0×10⁻⁶. 5 CFU / mL up to 5.0 × 10⁻⁶ 5 CFU / mL. Incubate at 37℃ and 150 rpm for 18 h with shaking. After incubation, serially dilute the eluent, plate it onto nutrient agar plates, and incubate at 37℃ for 24 h. Count the colonies. Test bacteria: Staphylococcus aureus, ATCC 6538; Escherichia coli, ATCC 8739.

[0045] Antibacterial rate is calculated using the following formula: Antibacterial rate / % = (BA) / B × 100% In the formula: A represents the number of viable bacteria in the sample group after shaking culture, in CFU / mL; B represents the number of viable bacteria (CFU / mL) in the control group (blank nonwoven fabric) after shaking culture in Comparative Example 1.

[0046] To further evaluate the antibacterial durability, the samples were washed in deionized water at 37°C and 100 rpm for 30 min with shaking. After washing, the water was replaced with fresh deionized water, and the process was repeated 20 times. After washing, the samples were dried at 45°C until the moisture content was 10%, and then the antibacterial test was performed. The result was recorded as the antibacterial rate after washing. Each group was tested 3 times, and the average value was taken.

[0047] Table 1. Results of antibacterial performance test Example 1 98.6 97.4 94.3 92.8 Example 2 99.1 98.0 95.1 93.6 Example 3 97.5 96.2 93.2 91.6 Comparative Example 1 6.8 5.5 4.3 3.8 Comparative Example 2 18.6 15.9 12.4 10.8 Comparative Example 3 73.5 69.2 46.8 42.5 Comparative Example 4 24.3 21.5 18.6 16.2 Comparative Example 5 86.4 82.7 69.8 65.1 Comparative Example 6 94.1 92.5 89.2 86.9 Comparative Example 7 58.6 53.4 50.2 46.1 Comparative Example 8 96.2 94.8 91.7 89.5 Comparative Example 9 88.5 84.9 77.3 72.6 Test Example 2: Mineralization Layer Fixation Stability Test: Samples from Examples 1-3 and Comparative Examples 2-9 were cut into 50mm × 50mm specimens, weighed, and placed in 50mL centrifuge tubes. 30mL of deionized water was added, and the samples were shaken at 37℃ and 100r / min for 30min. The washing was repeated 3 times. Fresh deionized water was used after each washing, and the process was repeated 20 times. After washing, the samples were dried at 45℃ until the moisture content was 10%, and then an antibacterial test was performed.

[0048] Element retention rate is calculated using the following formula: Element retention rate / % = Element content after washing / Element content before washing × 100% P and Si are used to characterize the calcium-phosphorus / silicon mineralization structure formed by mineralization induction solution A, while Zn and Sr are used to characterize the fixation stability of functional ions in mineralization fixation solution B.

[0049] Table 2 Results of the stability test of the mineralized layer Example 1 91.4 85.6 88.7 86.9 Example 2 89.6 83.8 90.5 88.2 Example 3 92.8 88.4 84.6 82.7 Comparative Example 2 - - - - Comparative Example 3 - - 48.6 45.3 Comparative Example 4 82.5 77.4 - - Comparative Example 5 68.7 61.5 70.2 66.4 Comparative Example 6 90.8 - 86.5 84.1 Comparative Example 7 91.2 84.9 - 86.2 Comparative Example 8 91.0 85.2 88.1 - Comparative Example 9 91.3 85.4 87.5 86.4 Test Example 3: Skin Repair Auxiliary Performance Test: HaCaT keratinocytes were seeded in 6-well plates, with 5 × 10⁶ cells per well. 5 Culture individual cells until cell confluence reaches 90% or higher. Use a sterile 200 μL pipette tip to draw a straight line along the center of the cell monolayer, and gently wash twice with PBS to remove detached cells.

[0050] The samples were cut into 10mm×10mm pieces, sterilized with UV light for 30min, and added to serum-free DMEM medium at a ratio of sample surface area to culture medium volume of 3cm² / mL. The samples were extracted at 37℃ for 24h and filtered through a 0.22μm filter membrane to obtain the sample extract. Subsequently, the sample extracts from Examples 1-3 and Comparative Examples 1-9 were added and cultured for another 24h. Three replicates were set for each group, and the average value of the results was taken.

[0051] Images were taken using an inverted microscope at 0h and 24h, and the scratch area was measured using ImageJ software. Cell migration rate was calculated using the following formula: Cell migration rate / % = (0h scratch area - 24h scratch area) / 0h scratch area × 100%.

[0052] Table 3. Auxiliary Tests for Skin Repair Example 1 77.6 Example 2 75.8 Example 3 79.4 Comparative Example 1 43.5 Comparative Example 2 52.8 Comparative Example 3 59.6 Comparative Example 4 57.4 Comparative Example 5 61.2 Comparative Example 6 66.5 Comparative Example 7 72.4 Comparative Example 8 64.2 Comparative Example 9 67.6 The results above indicate that the nonwoven fabric prepared by this invention possesses good antibacterial properties, mineralization layer fixation stability, and skin repair auxiliary properties. In Example 1, treatment with mineralization induction solution A for 7 minutes and mineralization fixation solution B for 10 minutes resulted in a relatively balanced overall antibacterial performance, mineralization layer stability, and repair auxiliary properties. This indicates that the treatment conditions allow for sufficient confined mineralization of phosphate, silicate, and calcium ions in the calcium alginate network, further fixing zinc ions, strontium ions, and lactoferrin peptides. In Example 2, shortening the treatment time with mineralization induction solution A and extending the treatment time with mineralization fixation solution B slightly improved the antibacterial effect and the retention of antibacterial properties after washing. This suggests that extending the treatment time with mineralization fixation solution B is beneficial for further fixing zinc ions and lactoferrin peptides in the mineralization layer, thereby improving antibacterial performance. Example 3 shows that extending the treatment time of mineralization induction solution A and shortening the treatment time of mineralization fixation solution B resulted in better skin repair auxiliary performance, indicating that a more sufficient calcium-phosphorus / silicon mineralization precursor layer is conducive to the formation of a silicon-containing low-crystallinity mineralization structure and has a more positive promoting effect on HaCaT cell migration.

[0053] Comparative Example 1 only pretreated the nonwoven fabric substrate, without loading sodium alginate or forming a calcium alginate network and mineralization functional layer. Therefore, its antibacterial and repair-aiding properties were weak, indicating that ordinary nonwoven fabric substrates themselves do not possess the functional effects described in this invention. Comparative Example 2, although subjected to sodium alginate loading and calcium ion replacement to form a certain calcium alginate network, was not treated with mineralization induction solution A and mineralization fixation solution B, and thus could not introduce a calcium-phosphorus / silicon mineralization layer, zinc ions, strontium ions, and lactoferrin peptides. Therefore, its antibacterial and repair effects remained limited. These results indicate that the calcium alginate network mainly provides hydrophilicity, calcium source, and confined template, but it is insufficient on its own to produce significant antibacterial and repair effects.

[0054] Comparative Example 3 omitted the treatment with mineralization induction solution A and directly used mineralization fixation solution B. Although mineralization fixation solution B contained zinc ions, strontium ions, and lactoferrin peptides, due to the lack of a pre-formed calcium-phosphorus / silicon mineralization precursor layer, the above functional components mainly adhered to the nonwoven fabric surface through ordinary adsorption or weak coordination, resulting in insufficient fixation stability and a significant decrease in antibacterial effect after washing. This indicates that the calcium-phosphorus / silicon precursor layer formed by mineralization induction solution A is a key foundation for the subsequent stable fixation of zinc, strontium, and lactoferrin peptides. Comparative Example 4 only treated with mineralization induction solution A without mineralization fixation solution B. Although a certain calcium-phosphorus / silicon deposition structure could be formed, the lack of zinc ions, strontium ions, and lactoferrin peptides resulted in unsatisfactory antibacterial and repair auxiliary effects, indicating that mineralization fixation solution B is an important step in imparting functional effects.

[0055] Comparative Example 5, which omitted sodium γ-polyglutamate and sodium phytate in the mineralization induction solution A, exhibited lower antibacterial properties, mineralization layer stability, and repair-aiding properties compared to Example 1. This indicates that sodium γ-polyglutamate and sodium phytate are not ordinary auxiliary additives, but rather play a role in regulating the calcium and phosphorus deposition rate, inhibiting particle coarsening, and promoting the uniform formation of the mineralization layer during the mineralization process. Without this regulatory system, calcium and phosphorus mineralization deposition is more prone to forming uneven or coarse particle structures, leading to decreased bonding stability between the mineralization layer and the nonwoven fibers, and further affecting the fixation effects of zinc, strontium, and lactoferrin peptides.

[0056] In Comparative Example 6, sodium silicate was omitted from the mineralization induction solution A. While its antibacterial properties remained at a good level, its skin repair auxiliary properties were lower than in Example 1. This indicates that sodium silicate primarily does not simply provide antibacterial effects, but rather participates in the construction of a silicon-containing, low-crystallinity calcium-phosphorus mineralization layer, thereby improving the surface microenvironment and promoting cell migration. In Comparative Example 7, omitting zinc gluconate significantly reduced antibacterial properties, indicating that zinc ions are an important factor in the antibacterial effect of this invention. In Comparative Example 8, omitting strontium lactate reduced repair auxiliary properties, indicating that strontium ions have a positive effect on cell migration and repair auxiliary effects. In Comparative Example 9, omitting lactoferrin peptide reduced both antibacterial and repair auxiliary properties, indicating that lactoferrin peptide not only participates in antibacterial activity but also works with the zinc, strontium, and silicon co-doped mineralization layer to improve skin repair effects.

Claims

1. A method for preparing in-situ ion-exchange modified nonwoven fabric, characterized in that, Includes the following steps: S1. Clean and dry the non-woven fabric substrate to obtain a pretreated non-woven fabric substrate; S2. The pretreated nonwoven fabric substrate is impregnated with sodium alginate solution, and then subjected to vacuum treatment, squeezing and drying to obtain a semi-dry nonwoven fabric loaded with sodium alginate, with its moisture content controlled at 20%-40%. S3. The semi-dry nonwoven fabric obtained in step S2 is sequentially immersed in calcium lactate aqueous solution and calcium chloride aqueous solution to carry out ion exchange reaction, and then aqueous calcium alginate modified nonwoven fabric is obtained. S4. The aqueous calcium alginate modified nonwoven fabric obtained in step S3 is sequentially immersed in mineralization induction solution A and mineralization fixation solution B for mineralization treatment, and then washed and dried to obtain the final product. The mineralization induction solution A contains a phosphorus source and a silicon source, and the mineralization fixation solution B contains a zinc source, a calcium source, a strontium source, and lactoferrin peptide.

2. The preparation method according to claim 1, characterized in that, In step S2, the mass concentration of the sodium alginate solution is 1-3%; the vacuum degree of the vacuum treatment is -0.05MPa to -0.1MPa, and the treatment time is 1-10min; the drying is hot air drying at a temperature of 40-60℃ until the moisture content is 25-35%.

3. The preparation method according to claim 1, characterized in that, In step S3, the calcium lactate aqueous solution has a mass concentration of 0.5-2%, a pH of 6.5-7.0, and a treatment time of 1-5 min; the calcium chloride aqueous solution has a mass concentration of 1-2%, a treatment time of 3-10 min; and the treatment temperature is 20-30℃.

4. The preparation method according to claim 1, characterized in that, In step S3, after the ion exchange treatment, a washing and rolling process is also included to control the liquid carryover rate to 100-150%.

5. The preparation method according to claim 1, characterized in that, The mineralization induction solution A comprises the following components in parts by weight: 10-30 parts by weight of sodium glycerophosphate, 1-5 parts by weight of sodium dihydrogen phosphate, 0.5-3 parts by weight of sodium γ-polyglutamate, 0.5-2 parts by weight of sodium silicate, 0.5-3 parts by weight of sodium phytate, and 4000-6000 parts by weight of water. After stirring and dissolving, the pH value is adjusted to 5.5-6.5 with lactic acid.

6. The preparation method according to claim 1, characterized in that, The mineralization fixative B comprises the following components in parts by weight: weigh 8-16 parts by weight of zinc gluconate, 3-8 parts by weight of calcium chloride, 1-4 parts by weight of strontium lactate, 4-8 parts by weight of lactoferrin peptide and 6000-10000 parts by weight of water, stir to dissolve, and adjust the pH value to 6.5-7.0 with lactic acid to obtain the final solution.

7. The preparation method according to claim 1, characterized in that, The mineralization treatment in step S4 is carried out at a temperature of 25-35℃, with a treatment time of 5-10 min in mineralization induction solution A and 8-15 min in mineralization fixation solution B. The drying after treatment is carried out by hot air drying at a temperature of 40-50℃ until the moisture content is 5-15%.

8. An in-situ ion-displacement modified nonwoven fabric obtained by the preparation method according to any one of claims 1-7, characterized in that, The nonwoven fabric includes a nonwoven fabric substrate and a calcium alginate network structure generated in situ on and inside the surface of the nonwoven fabric substrate. The calcium alginate network structure is loaded with a low-crystallinity calcium phosphate mineralization deposit layer, which contains calcium, phosphorus, silicon, zinc and strontium.

9. The in-situ ion-exchange modified nonwoven fabric according to claim 8, characterized in that, The mineralized sedimentary layer also contains lactoferrin peptides.