Semi-water-repellent spunlace nonwoven fabric, and preparation method and application thereof

Abstract

This invention relates to a semi-water-repellent spunlace nonwoven fabric, its preparation method, and its application. The invention provides a method for preparing a semi-water-repellent spunlace nonwoven fabric, comprising the following steps: (1) placing the spunlace nonwoven fabric in water, adding a refining agent, a stabilizer, and liquid alkali, and then performing a first heating; adding hydrogen peroxide, immediately performing a second heating, and performing debleaching; (2) sequentially washing and neutralizing the spunlace nonwoven fabric, and finally dehumidifying and drying it to obtain a semi-water-repellent spunlace nonwoven fabric; one side of the spunlace nonwoven fabric is a cotton fiber layer, and the other side is a polyester fiber layer. This invention, through precise control of bleaching without degreasing of a spunlace nonwoven fabric with a specific structure, selectively retains the natural cotton wax in the cotton fibers while removing impurities and pigments to achieve bleaching, thereby activating and utilizing the natural water-repellent properties of the cotton fibers, ultimately obtaining a high-performance composite material with a semi-water-repellent effect on one side and inherent water-repellent properties on the other.

Description

Technical Field

[0001] This invention relates to the field of nonwoven fabric processing technology, specifically to a semi-water-repellent spunlace nonwoven fabric, its preparation method, and its application. Background Technology

[0002] Spunlace nonwoven fabrics are widely used in medical dressings, wipes, and hygiene products due to their softness, breathability, and lint-free properties. Pure cotton spunlace nonwoven fabrics have excellent skin-friendliness and biocompatibility, but their natural hydrophilicity becomes a drawback in certain applications (such as medical protective materials requiring a certain degree of liquid resistance, and dry wipes). Currently, the industry mainly uses two methods to impart water-repellent properties to materials: firstly, processing with chemical fibers that inherently possess water-repellent properties (such as polypropylene and polyester); secondly, after the material is formed, applying additional chemical water-repellent agents such as fluorine-containing, silicon-containing, or hydrocarbon-based agents through coating, spraying, or impregnation processes to form a hydrophobic film on the fiber surface, thereby achieving a water-repellent effect.

[0003] However, these traditional methods have significant limitations: First, synthetic fibers are inferior to cotton fibers in terms of biocompatibility, skin friendliness, and biodegradability; second, the chemical water-repellent agents added during finishing may lead to increased costs, a stiffer hand feel, and reduced breathability, with some water-repellent agents (such as long-chain fluorocarbons) posing potential biocompatibility risks and environmental controversies. To impart water repellency to cotton materials, chemical finishing agents (such as fluorinated and hydrocarbon-based water-repellent agents) are typically used, but this can lead to increased costs, a stiffer hand feel, potential biocompatibility risks, and environmental problems. On the other hand, cotton fibers themselves contain approximately 0.5%-1.0% natural cotton wax, a natural water-repellent substance. However, in traditional cotton fabric bleaching pretreatment processes, to obtain extremely high whiteness and wicking effect (hydrophilicity), strong alkalis and oxidants are usually used, combined with high-temperature treatment. This process almost completely removes the cotton wax, causing the cotton fibers to lose their natural water repellency. In the existing technology, there is a lack of a process that can precisely control the degree of processing, effectively remove impurities and achieve bleaching, while deliberately retaining this part of the natural cotton wax.

[0004] Therefore, developing a process to prepare functional spunlace nonwoven fabrics with semi-water-repellent effects without the need for additional chemical water-repellent agents, and by retaining and utilizing the natural water-repellent components of cotton fibers through specific processes, has significant application value and market prospects. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a semi-water-repellent spunlace nonwoven fabric, its preparation method, and its application. The present invention achieves bleaching without degreasing of a spunlace nonwoven fabric with a specific structure by precisely controlling the process. While removing impurities and pigments to achieve bleaching, it selectively retains the natural cotton wax in the cotton fibers, thereby activating and utilizing the natural water-repellent properties of the cotton fibers. Ultimately, a high-performance composite material with a semi-water-repellent effect on one side and inherent water-repellent properties on the other side is obtained.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: Based on the above technical solution, the present invention can be further improved as follows.

[0007] The first objective of this invention is to provide a method for preparing a semi-water-repellent spunlace nonwoven fabric, comprising the following steps: (1) Place the spunlace nonwoven fabric in water, add refining agent, stabilizer and liquid alkali, and then raise the temperature for the first time; add hydrogen peroxide and immediately raise the temperature for the second time to remove bleach; (2) The spunlace nonwoven fabric is washed and neutralized in sequence, and finally dehumidified and dried to obtain a semi-water-repellent spunlace nonwoven fabric.

[0008] One side of the spunlace nonwoven fabric is a cotton fiber layer, and the other side is a polyester fiber layer.

[0009] The beneficial effects of this invention are: the process of this invention involves precisely controlled bleaching without degreasing of spunlace nonwoven fabric with a specific structure. While removing impurities and pigments to achieve bleaching, it selectively retains the natural cotton wax in the cotton fibers, thereby activating and utilizing the natural water-repellent properties of the cotton fibers. The final product is a high-performance composite material with a semi-water-repellent effect on the cotton side and an inherent water-repellent property on the polyester side.

[0010] Furthermore, the weight ratio of water to spunlace nonwoven fabric in step (1) is 9~10:1.

[0011] The beneficial effects of adopting the above-mentioned further solutions are: the present invention does not require the use or synthesis of additional water-repellent finishing agents, thus avoiding the associated costs, feel, and potential environmental / health risks, making the products more natural and safe, and especially suitable for high-end medical and hygiene products.

[0012] Furthermore, in step (1), the weight ratio of the spunlace nonwoven fabric, the refining agent, the stabilizer, and the liquid alkali is 1:0.01~0.04:0.003~0.009:0.02~0.03; The weight ratio of hydrogen peroxide to spunlace nonwoven fabric is 0.05-0.3:1; the mass concentration (OWF) of hydrogen peroxide is the amount of hydrogen peroxide used / weight of nonwoven fabric; the concentration of hydrogen peroxide is 25%~30%; and the mass concentration of liquid alkali is 30%~35%.

[0013] Furthermore, the hydrogen peroxide has a mass concentration of 27.5%; the liquid alkali has a mass concentration of 32%.

[0014] Furthermore, the heating rate of the first heating in step (1) is 2℃ / min~3℃ / min, and the temperature is raised to 58℃~62℃; The second heating rate is 2℃ / min~3℃ / min, and the temperature is raised to 85℃~90℃.

[0015] The beneficial effects of adopting the above-mentioned further solution are: the present invention achieves the effect of "bleaching without degreasing": by precisely controlling the dosage of alkali (liquid alkali), oxidant (hydrogen peroxide), heating curve (especially slowly heating to 88°C instead of the traditional 95°C or above), and treatment time, the present invention effectively decomposes and removes impurities such as pectin, protein, and pigments in cotton fibers, achieving the purpose of bleaching, while maximizing the protection of the natural cotton wax on the surface of cotton fibers from being saponified or emulsified and removed.

[0016] Furthermore, the cyclic bleaching time in step (1) is 20 min to 30 min.

[0017] Furthermore, the water washing in step (2) specifically involves injecting room temperature soft water, heating it to 50°C, and washing for 10 minutes; after draining the water washing liquid, soft water is added again to perform a fixed wash for 4 minutes to 5 minutes and an overflow wash for 4 minutes to 5 minutes.

[0018] Furthermore, the temperature of the constant wash and the overflow wash are both at room temperature; during the constant wash and the overflow wash, the water flows outward, the pump speed is 50-60%, and the drive motor is a variable frequency motor.

[0019] Furthermore, the dehumidification time in step (2) is 50 min to 80 min, the drying temperature is 110℃ to 150℃, and the surface drying weight loss of the semi-water-repellent spunlace nonwoven fabric is 2% to 6%.

[0020] Furthermore, in step (2), an acid solution is added during neutralization, the concentration of which is 95% to 99.6%; the acid solution is at least one of sulfuric acid solution and oxalic acid solution; and the pH value after neutralization is 5.0 to 7.0.

[0021] Furthermore, when the acid solution is a sulfuric acid solution, the concentration of the sulfuric acid solution is 98%.

[0022] Furthermore, when the acid solution is an oxalic acid solution, the concentration of the oxalic acid solution is 99.6%.

[0023] Furthermore, during washing, a variable frequency pump is used to drive high-pressure water flow in an alternating "outer flow-inner flow" mode to forcefully penetrate the fabric roll.

[0024] The beneficial effects of adopting the above-mentioned further solutions are: the specific internal and external flow circulation mode and variable frequency pump control ensure the uniformity of the inner and outer layer treatment of the roll nonwoven fabric, avoiding performance differences caused by uneven treatment. The step-by-step water washing and precise acid neutralization process effectively remove residual chemicals, ensuring the purity and safety of the product.

[0025] The second objective of this invention is to provide a semi-water-repellent spunlace nonwoven fabric prepared by the aforementioned preparation method.

[0026] A third objective of this invention is to provide an application of a semi-water-repellent spunlace nonwoven fabric, which is used in the preparation of medical and / or hygiene products.

[0027] The beneficial effects of this invention are as follows: the spunlace nonwoven fabric of this invention has a durable semi-water-repellent effect on its cotton side due to the retention of natural cotton wax, where liquid forms beads on its surface instead of immediately penetrating; the polyester side, due to the nature of the material, has inherent water repellency. This asymmetrical water-repellent structure gives it a unique advantage in products such as disposable surgical gowns, surgical drapes, and specific wipes, as it can resist liquid penetration while maintaining the comfort of the cotton side in contact with the skin. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating the preparation process of Example 1 of the present invention; Figure 2 This is a schematic diagram of the structure of the semi-water-repellent spunlace nonwoven fabric of Embodiment 1 of the present invention. Detailed Implementation

[0029] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0030] The spunlace nonwoven fabric used in the following examples has one side consisting of a 100% cotton fiber layer and the other side consisting of a 100% water-repellent polyester fiber layer. The nonwoven fabric has a basis weight of 35gsm-45gsm and is packaged in rolls of approximately 1.2 tons each.

[0031] Example 1: Preparation of semi-water-repellent spunlace nonwoven fabric like Figure 1 , 2 As shown: (1) Horizontally load two rolls of spunlace nonwoven fabric, totaling approximately 2.4 tons, into a 23m³ volume container. 3In a horizontal bleaching pan, add 9-10 times the weight of the spunlace nonwoven fabric to the pan. At approximately 25°C, sequentially add 1% of the weight of the spunlace nonwoven fabric as a high-efficiency refining agent (comprising 15% by mass of fatty alcohol polyoxyethylene ether (CAS No. 9064-14-6), 10% by mass of fatty alcohol ethoxylate (CAS No. 68920-66-1), and 5% by mass of acrylic polyoxyethylene ether phosphate), 0.6% of the weight of the spunlace nonwoven fabric as a stabilizer (10% by mass of polyhydroxy polycarboxylic acid (CAS No. 62601-60-9) and 15% by mass of sodium polyacrylate (CAS No. 76774-25-9)), and 2.4% by weight of the spunlace nonwoven fabric as liquid alkali (32% by mass concentration). Start the circulation pump to begin the first heating at a rate of 2.5°C / min to 3.0°C / min. When the temperature rises to 60℃, hydrogen peroxide additive of 10% of the weight of the spunlace nonwoven fabric is slowly added to the system through the dosing system. After feeding is complete, continue heating at a rate of 2.5℃ / min~3℃ / min to 88℃. Once 88℃ is reached, start timing and run the de-bleaching process for 50-70 minutes before draining. During this stage, the variable frequency pump drives high-pressure water flow in an alternating "outer flow-inner flow" mode to forcefully penetrate the fabric roll. The optimal de-bleaching time is 50 minutes.

[0032] (2) Inject room temperature soft water, heat to 50℃ and wash for 10 minutes; after draining, add water again for a 4-minute fixed wash and a 5-minute overflow wash. The fixed wash and overflow wash are both room temperature fixed washes. The overflow wash requirements are: water flow outward, pump speed 50-60%, and the drive motor is a variable frequency motor. After washing, 3-5 kg ​​of concentrated sulfuric acid is added to a 300-500 L soft water mixing tank for dilution. The diluted concentrated sulfuric acid is then added to a bleaching tank for neutralization and circulation. During neutralization, the water level in the bleaching tank is 21000 L-22000 L, using an external circulation method for 18 minutes. The pH value of the system is monitored online. When the pH value stabilizes at 5-7, neutralization is stopped. The neutralized spunlace nonwoven fabric is then removed from the bleaching tank and sequentially fed into a dehumidifier and dryer for dehumidification and drying. The dehumidification time is 50-80 minutes, and the drying temperature is controlled at 110℃-150℃, with a fabric surface weight loss of 2%-6% as the control standard. After drying and setting, a semi-water-repellent spunlace nonwoven fabric is obtained.

[0033] The final product obtained according to GB / T 24218.6 test Example 1 has a white and soft cotton side with an absorption time of more than 5 minutes, exhibiting a significant semi-water-repellent effect; the polyester side is completely water-repellent. This product is particularly suitable for use as a base material for surgical drapes, mask linings, etc. The cotton side keeps the skin dry and breathable, improving comfort, while the semi-water-repellent properties of both the polyester and cotton sides effectively prevent liquid penetration during surgery.

[0034] Example 2: The only difference between Example 2 and Example 1 is that the mass fractions of the high-efficiency refining agent, stabilizer, liquid alkali, and hydrogen peroxide in step (1) are different relative to the spunlace nonwoven fabric. The other steps and conditions are the same as those in Example 1. The specific mass fractions of the high-efficiency refining agent, stabilizer, liquid alkali, and hydrogen peroxide in Example 2 relative to the spunlace nonwoven fabric are shown in Table 1. Table 1 Comparative Examples 1-3: Compared with Example 1, the only difference between Comparative Examples 1 to 3 is that the mass fractions of the high-efficiency refining agent, stabilizer, liquid alkali, and hydrogen peroxide in step (1) are different from those of the spunlace nonwoven fabric. The other steps and conditions are the same as those of Example 1. The specific mass fractions of the high-efficiency refining agent, stabilizer, liquid alkali, and hydrogen peroxide in Comparative Examples 1 to 3 compared to the spunlace nonwoven fabric are shown in Table 2: Table 2 Performance testing: Physicochemical tests were conducted on the spunlace nonwoven fabrics prepared in Examples 2-5 at uniform intervals of 20-30 cm along the width direction. Each group had six test points. The water absorption time of the spunlace nonwoven fabric was tested according to Appendix B of YY / T 0472.1; the sampling basis weight of the spunlace nonwoven fabric was tested according to GB / T 24218.1; the pH of the spunlace nonwoven fabric was tested according to GB / T 7573-2009; and the whiteness of the spunlace nonwoven fabric was tested according to YY0331-2002. The fabric appearance was evaluated visually and using a WSB-3A intelligent digital whiteness meter. The results are shown in Table 3. Table 3 Table 3 shows that the water absorption time of the semi-water-repellent spunlace nonwoven fabric prepared in Example 2 is qualified, while the water absorption time of Comparative Examples 2 and 3 is short and unqualified. Although Comparative Example 1 has better water absorption performance, there are a large number of yellow-green spots on the fabric surface that have not been cleaned. Therefore, it can be concluded that the semi-water-repellent spunlace nonwoven fabric prepared in Example 2 has the best overall performance.

[0035] In summary, this invention achieves the effect of "bleaching without degreasing": by precisely controlling the dosage of alkali (liquid alkali), oxidant (hydrogen peroxide), heating curve (especially slowly heating to 88°C instead of the traditional 95°C or above), and processing time, this invention effectively decomposes and removes impurities such as pectin, protein, and pigments from cotton fibers, achieving the purpose of bleaching, while maximizing the protection of the natural cotton wax on the surface of cotton fibers from being saponified or emulsified and removed.

[0036] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a semi-water-repellent spunlace nonwoven fabric, characterized in that, Includes the following steps: (1) Place the spunlace nonwoven fabric in water, add refining agent, stabilizer and liquid alkali, then raise the temperature for the first time, add hydrogen peroxide, and immediately raise the temperature for the second time to remove bleach; (2) The spunlace nonwoven fabric is washed and neutralized in sequence, and finally dehumidified and dried to obtain a semi-water-repellent spunlace nonwoven fabric. One side of the spunlace nonwoven fabric is a cotton fiber layer, and the other side is a polyester fiber layer.

2. The method for preparing a semi-water-repellent spunlace nonwoven fabric according to claim 1, characterized in that, The weight ratio of water to spunlace nonwoven fabric in step (1) is 9~10:

1.

3. The method for preparing a semi-water-repellent spunlace nonwoven fabric according to claim 1, characterized in that, The weight ratio of the spunlace nonwoven fabric, the refining agent, the stabilizer, and the liquid alkali in step (1) is 1:0.01~0.04:0.003~0.009:0.02~0.03; The weight ratio of hydrogen peroxide to spunlace nonwoven fabric is 0.05-0.3:1; the mass concentration of hydrogen peroxide is 25%~30%; and the mass concentration of liquid alkali is 30%~35%.

4. The method for preparing a semi-water-repellent spunlace nonwoven fabric according to claim 1, characterized in that, The heating rate for the first heating in step (1) is 2℃ / min~3℃ / min, and the temperature is raised to 58℃~62℃; The second heating rate is 2℃ / min~3℃ / min, and the temperature is raised to 85℃~90℃.

5. The method for preparing a semi-water-repellent spunlace nonwoven fabric according to claim 1, characterized in that, The cyclic bleaching time in step (1) is 20 min to 30 min.

6. The method for preparing a semi-water-repellent spunlace nonwoven fabric according to claim 1, characterized in that, The water washing in step (2) specifically involves injecting room temperature soft water, heating it to 50°C, and washing for 10 minutes; after draining the water washing liquid, adding soft water again to perform a fixed wash for 4 minutes to 5 minutes and an overflow wash for 4 minutes to 5 minutes.

7. The method for preparing a semi-water-repellent spunlace nonwoven fabric according to claim 6, characterized in that, The dehumidification time in step (2) is 50 min to 80 min, the drying temperature is 110℃ to 150℃, and the surface drying weight loss of the semi-water-repellent spunlace nonwoven fabric is 2% to 6%.

8. The method for preparing a semi-water-repellent spunlace nonwoven fabric according to claim 1, characterized in that, In step (2), an acid solution is added during neutralization. The concentration of the acid solution is 95% to 99.6%. The acid solution is at least one of sulfuric acid solution and oxalic acid solution. The pH value after neutralization is 5.0 to 7.

0.

9. A semi-water-repellent spunlace nonwoven fabric, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 8.

10. An application of a semi-water-repellent spunlace nonwoven fabric, characterized in that, The spunlace nonwoven fabric of claim 9 is used in the preparation of medical and / or hygiene products.

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