Degradable soft cotton towel and preparation method thereof

Abstract

The invention discloses a degradable soft cotton towel and a preparation method thereof, relates to the technical field of fiber composite materials, and belongs to the patent classification number D01F8 / 02. The preparation method comprises the following steps: carrying out alkali treatment and enzymolysis on Egypt long stapled cotton fibers to obtain pretreated cotton fibers, and preheating, stretching and shaping polycaprolactone fibers to obtain pretreated polycaprolactone fibers; mixing and opening the two fibers, and performing air laying to form a fiber web; a super-absorbent network is constructed through impregnation of a main network solution carboxymethyl chitin and oxidized cellulose nanofibrils and an auxiliary network dispersion solution calcium alginate gel microspheres and a hyaluronic acid cross-linking body; performing hot pressing on a hexagonal nickel template to form micron bulges, and performing electrostatic spraying on modified nano silicon dioxide to obtain a matrix; spraying essence, drying in vacuum, slitting and sterilizing. The soft cotton towel has excellent water absorption performance through the synergistic effect of multistage pore channels, a super water absorption network and micro-nano surface modification, and the polycaprolactone fibers and the cotton fibers used by the soft cotton towel are mixed and have good biodegradability.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber composite materials, belongs to patent classification number D01F8 / 02, and specifically relates to a degradable cotton wipe and a preparation method thereof. Background Art

[0002] As a new type of cleaning and skincare product with a soft touch and pleasant user experience, cotton wipes have seen increasing adoption in recent years across personal care, daily cleaning, and medical care consumables. Their delicate, skin-friendly nature and resistance to shedding provide gentle cleansing and care, making them particularly suitable for infants and those with sensitive skin who demand a high level of comfort. Furthermore, cotton wipes offer the flexibility of wet or dry use, accommodating a variety of needs, including makeup removal, cleansing, and daily wiping. They are becoming a popular alternative to traditional paper towels and cotton pads, and are widely favored by consumers.

[0003] With growing environmental awareness and the growing popularity of sustainable development, consumers are placing higher demands on the biodegradability of cotton wipes. Currently, some cotton wipes on the market utilize a blend of cotton and other hydrophilic fibers to achieve excellent water absorption. However, these hydrophilic fibers are mostly non-degradable, such as chemically synthesized fibers like polyester and viscose. Polyester is produced through the chemical polycondensation of organic dibasic acids and diols, while viscose is produced through chemical processing and extraction from raw materials such as wood pulp.

[0004] The widespread use of these non-degradable fibers has created serious environmental problems. With the rapid growth in cotton wipe usage, discarded cotton wipes are extremely difficult to degrade in the natural environment. Long-term accumulation not only occupies significant land resources, but also damages soil structure and ecosystems, impacting the habitats of plants and animals, creating "white pollution" and placing a heavy burden on the environment. Summary of the Invention

[0005] The present invention aims to provide a degradable cotton wipe and a method for preparing the same, in order to solve the technical problems raised by the above-mentioned background art. The cotton wipe prepared by the present invention not only has good degradability but also has excellent water absorption performance, thereby meeting the needs of daily skin hygiene care.

[0006] To achieve the above object, the present invention provides the following technical solutions: A method for preparing a degradable cotton wipe comprises the following steps: a) using Egyptian long-staple cotton fiber as raw material, first placing it in a sodium hydroxide aqueous solution for alkaline treatment, then repeatedly washing it with deionized water until it is neutral; then immersing the cotton fiber in a cellulase solution prepared with an acetate buffer for enzymatic hydrolysis, and heating and inactivating it after the enzymatic hydrolysis to obtain pretreated cotton fiber; b) taking polycaprolactone fibers as raw materials, preheating them in a hot air oven, stretching them at a constant stretching rate, and then immediately cooling and setting them to obtain pretreated polycaprolactone fibers; c) mixing the pretreated cotton fibers and the pretreated polycaprolactone fibers, opening them with a needle cloth opener, and then forming a fiber web with an air-laid machine; d) first preparing a main network solution obtained by dissolving carboxymethyl chitin and oxidized cellulose nanofilament in deionized water; then preparing an auxiliary network dispersion liquid obtained by dispersing calcium alginate gel microspheres and hyaluronic acid crosslinked bodies in deionized water and ultrasonic treatment; and then immersing the fiber web obtained in step c) in the auxiliary network solution, removing liquid with a roller, and drying, and then immersing it in the main network solution, removing liquid with a roller, and drying, so as to build a super water-absorbing network inside the fiber web, thereby obtaining a water-absorbing fiber web; e) selecting a nickel template with a hexagonal convex array, pressing the fiber web in a hot press, then naturally cooling and demolding, forming a micron-level protruding structure on the surface, preparing a nano-silicon dioxide ethanol suspension, uniformly spraying it on the surface of the water-absorbing fiber web using an electrostatic spraying device, and then drying to obtain a cotton-soft towel base; f) spraying the essence liquid on the cotton-soft towel base, then vacuum drying, and finally cutting and irradiation sterilization, thereby obtaining the product.

[0007] In the technical solution of the present invention, Egyptian long-staple cotton fibers are subjected to graded treatment to form a unique pore structure. This multi-scale pore system significantly improves the wetting performance through physical structure optimization. The alkali treatment process selectively dissolves the wax layer and primary cell wall on the fiber surface, exposing the cellulose microfibril bundles and forming a micron-scale groove structure. These grooves provide channels for rapid diffusion of liquids. Subsequent enzymatic hydrolysis further etches a nanoscale pore network inside the micron-grooves, significantly increasing the specific surface area and surface active sites of the fiber. The internal microchannels formed by the polycaprolactone fiber after stretching cooperate with the surface structure of the cotton fiber to construct a four-level continuous pore network of fiber gaps, fiber internal gaps, surface microgrooves and nanopores. This multi-level pore structure produces a gradient capillary effect, allowing the liquid to spontaneously penetrate rapidly along the pores from large pores to small pores. At the same time, the strong capillary force generated by the nanoscale pores ensures the uniform distribution and stable retention of the liquid inside the material. Secondly, in the construction of the super absorbent network of the biodegradable, highly absorbent cotton wipe, the primary and secondary absorbent networks achieve efficient water absorption, rapid water transfer, and stable water retention through complementary material properties and synergistic structures. The primary absorbent network is formed by carboxymethyl chitosan and oxidized cellulose nanofibrils dissolved in deionized water. Carboxymethyl chitosan contains a large number of hydrophilic carboxyl and hydroxyl groups, which have good water solubility and film-forming properties. Oxidized cellulose nanofibrils form a three-dimensional network with their high specific surface area and abundant hydroxyl groups. The viscous solution formed by the two is impregnated and adheres to the surface of the fiber mesh, forming a continuous hydrophilic film. This enhances the fiber mesh's affinity for liquids and fills the interfiber gaps, forming a continuous transmission channel from the surface to the interior, laying the foundation for rapid liquid penetration and diffusion. The auxiliary water-absorbing network is formed by ultrasonically dispersing calcium alginate gel microspheres and hyaluronic acid crosslinks. The three-dimensional network within the calcium alginate gel microspheres locks in water molecules through osmosis, while the hyaluronic acid crosslinks reduce water loss by forming a water-rich gel. Ultrasonic treatment breaks up the aggregates and evenly disperses them, forming a composite structure called a "main skeleton-dispersed water storage unit." The calcium alginate microspheres provide independent water storage spaces to prevent reverse osmosis, while the hyaluronic acid crosslinks fill the gaps and enhance water retention. The synergistic effect of these two elements is essentially the complementary function of "rapid transport" and "efficient water storage." The continuous channels of the main network ensure rapid liquid penetration to all areas, while the auxiliary network water storage units quickly absorb and store liquid upon arrival. The dispersed microspheres and crosslinks neither clog the channels nor swell to reduce pores, enhancing capillary pressure and counteracting water transport efficiency. This "skeleton-reservoir" structure resolves the conflict between water absorption and water retention inherent in a single material. Furthermore, the materials used are all naturally biodegradable, enhancing performance while ensuring environmental sustainability. Finally, by constructing micron-scale protrusions and nano-scale nano-silica protrusion structures on the fiber surface, the combination of the two forms a micro-nano protrusion structure that greatly improves the roughness of the fiber surface, increases the hydrophilicity of the fiber web surface, and increases the conduction of water from the surface to the inside. Figure 1This SEM image shows the surface of the cotton wipe substrate of the present invention. The surface of the fiber web exhibits a rough, uneven structure. Through this synergistic effect, the present invention provides the cotton wipe with excellent water absorption properties. Furthermore, the cotton and polycaprolactone fibers used in the present invention are highly biodegradable, causing no environmental pollution and contributing to its environmentally friendly nature.

[0008] Preferably, in step a), the concentration of the sodium hydroxide solution is 2-5 wt %, the alkali treatment temperature is 50-60° C., and the alkali treatment time is 10-20 min.

[0009] Preferably, in step b), the polycaprolactone fiber is preheated at a temperature of 85 to 90° C., for a time of 5 to 10 minutes, and stretched 2 to 3 times.

[0010] Preferably, in step c), the mass ratio of the pretreated cotton fiber to the pretreated polycaprolactone fiber is 10:3-7.

[0011] Preferably, in step d), the mass ratio of carboxymethyl chitosan to oxidized cellulose nanofibrils is 5:2-4.

[0012] Preferably, in step d), the mass ratio of calcium alginate gel microspheres to hyaluronic acid cross-linked body is 10:4-6.

[0013] Preferably, the preparation method of the cross-linked hyaluronic acid comprises the following steps: The hyaluronic acid powder is added to deionized water and stirred to dissolve, and then sodium hydroxide solution is added to adjust the pH to 8.5-9.0, and then 1,4-butanediol diglycidyl ether is added, heated and stirred to react, and washed and freeze-dried to obtain a hyaluronic acid cross-linked body.

[0014] Preferably, in step e), the nano-silicon dioxide is modified, comprising the following steps: The nano-silica is added to a mixed solvent of ethanol and water, and dispersed uniformly by ultrasonic oscillation. Then, γ-glycidyloxypropyltrimethoxysilane is added, and the pH is adjusted to 4-5. The mixture is heated and stirred for reaction, and the mixture is centrifuged, washed, and dried to obtain epoxidized nano-silica. Add dodecyldimethylaminopropylammonium chloride into deionized water, stir and dissolve, then add epoxidized nano-silica, heat and stir to react, and then centrifuge, wash and dry to obtain the product.

[0015] Preferably, in step f), the essence comprises the following components in parts by weight: 5-10 parts of peach gum polysaccharide, 2-5 parts of collagen, 1-3 parts of sodium hyaluronate, 1-3 parts of glycerin, and 80-90 parts of deionized water.

[0016] In the technical solution of the present invention, as described above, nano-silica is incorporated into the surface of the fiber web to increase its surface roughness, thereby enhancing its surface hydrophilicity. However, the present invention team encountered a further problem during their experiments: a large amount of nano-silica fell off the fiber web surface during the subsequent drying process, affecting its effect on improving the surface hydrophilicity of the fiber web. To further solve this problem, the present invention modifies nano-silica. First, γ-glycidyloxypropyltrimethoxysilane is grafted onto the nano-silica to load epoxy functional groups on its surface. Then, the epoxy functional groups are used to undergo a ring-opening reaction with the amino groups on dodecyldimethylaminopropylammonium chloride, thereby grafting dodecyldimethylaminopropylammonium chloride onto the surface of the nano-silica. This makes the surface of the silica positively charged, while the fiber web is negatively charged under the action of carboxymethyl chitosan and oxidized cellulose nanofibrils. Under electrostatic force, the nano-silica can be firmly bonded to the surface of the fiber web, thereby forming a significant micro-nano composite structure on the surface of the fiber web, thereby improving the roughness of the fiber surface and further improving the hydrophilicity of the surface.

[0017] A degradable cotton soft towel is prepared by the above method.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. Through the multi-level pore structure design (a four-level continuous pore network of fiber gaps, internal gaps, surface microgrooves and nanopores), a gradient capillary effect is generated. Combined with the synergistic effect of the main water absorption network (carboxymethyl chitin and oxidized cellulose nanofibrils to construct a continuous hydrophilic transmission channel) and the auxiliary water absorption network (calcium alginate gel microspheres and hyaluronic acid cross-linked bodies to form a "skeleton-reservoir" water storage structure), the water absorption speed, water absorption and water retention stability of the cotton wipes are greatly improved. At the same time, the surface micro-nano protrusion structure enhances hydrophilicity, meeting the needs of efficient water absorption in daily cleaning and medical care consumables, and improving the poor water absorption performance of traditional biodegradable cotton wipes.

[0019] 2. Naturally degradable Egyptian long-staple cotton fiber and polycaprolactone fiber are used as the base material, and the water-absorbing network and essence ingredients are all made of naturally degradable materials; performance is improved through physical modification (hot embossing, electrostatic spraying, etc.) and structural optimization without sacrificing the degradable properties of the material, solving the contradiction between high water absorbency and environmental protection in traditional technology, reducing pollution to the environment after use, and conforming to the trend of green consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an SEM image of the surface of the cotton wipe substrate of the present invention. DETAILED DESCRIPTION

[0021] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0022] Example 1 A method for preparing a degradable cotton wipe comprises the following steps: Step a: Weigh 500g of Egyptian long-staple cotton fiber and place it in 5000mL of a 3wt% sodium hydroxide aqueous solution in a 55°C water bath with stirring for 15 minutes (stirring at 200rpm). After treatment, rinse the fiber repeatedly with deionized water until the pH of the washing solution reaches 7.0±0.2. Immerse the alkali-treated cotton fiber in a cellulase solution (enzyme activity 2000U / g, fiber to solution mass volume ratio 1:10) prepared in acetate buffer at pH 4.8. Enzymatic hydrolysis is carried out in a shaking water bath at 45°C (150rpm) for 30 minutes. Immediately after the enzymatic hydrolysis, the system is heated to 80°C and maintained for 10 minutes to inactivate the enzyme. Filter the pretreated cotton fiber and place it in a well-ventilated area to drain for later use.

[0023] Step b: Weigh 200g of polycaprolactone fiber (1.5 dtex), lay it flat in a hot air oven, and preheat it at 88°C for 8 minutes. Secure the preheated fiber to a stretching device and stretch it to 2.8 times its original length at a constant rate of 10mm / min. Immediately after stretching, blow it with cold air to room temperature to set the shape. This yields pretreated polycaprolactone fiber, which should be sealed and stored to protect from moisture.

[0024] Step c: Mix the pretreated cotton fiber and pretreated polycaprolactone fiber in a mass ratio of 10:6 (total weight 700g), place them in an opener with a card cloth spacing of 0.5mm and open them three times to ensure that the fibers are evenly mixed. The opened mixed fiber is sent to the air-laid machine with the working pressure set at 0.6MPa, the ambient temperature at 25±1℃, the relative humidity at 60±5%, and the prepared weight is 50±2g / m 2 The fiber web should be made of a uniform fiber web with a coefficient of variation of ≤8%. Immediately after forming the web, pre-press it with a 0.5MPa pressure roller for 30 seconds to enhance the bonding strength between fibers.

[0025] Step d: Prepare the main network solution: weigh 25 g of carboxymethyl chitosan (88% deacetylation degree) and 18 g of oxidized cellulose nanofibrils (30 nm in diameter), add them together into 460 mL of deionized water, and stir at 50°C for 2 hours until they are completely dissolved to form a uniform viscous solution.

[0026] Prepare the auxiliary network dispersion: Add 500 mL of deionized water to a beaker, weigh 5 g of hyaluronic acid powder, and stir at 200 rpm using a magnetic stirrer for 30 minutes until the hyaluronic acid is completely dissolved. Next, slowly add 1 mol / L sodium hydroxide solution dropwise, checking the pH with pH paper, to adjust the solution to 8.5-9.0. Slowly add 2 g of 1,4-butanediol diglycidyl ether to the solution while increasing the stirring speed to 300 rpm. Place the beaker in a 40°C water bath and continue stirring for 6 hours. After the reaction is complete, transfer the mixture to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes. Discard the supernatant. Wash the precipitate three times with deionized water, centrifuging again after each wash. The washed precipitate was placed in a freeze dryer, pre-frozen at -40°C for 2 hours, and then freeze-dried at a vacuum degree of ≤10 Pa for 12 hours to obtain a hyaluronic acid cross-linked product.

[0027] Weigh 20g of calcium alginate gel microspheres (particle size 30μm) and 11g of hyaluronic acid crosslinker, add them to 300mL of deionized water, and treat them using a 40kHz, 300W ultrasonic device for 15 minutes until uniformly dispersed. The fiber web obtained in step c was first passed through an auxiliary network dispersion solution immersion tank at a speed of 2m / min (immersion time 60 seconds), dehydrated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 2 minutes. The fiber web was then passed through a main network solution immersion tank at the same speed (immersion time 30 seconds), dehydrated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 3 minutes to obtain a water-absorbent fiber web.

[0028] Step e: Select a nickel template with a hexagonal protrusion array with a height of 30 μm and a spacing of 80 μm, spread the absorbent fiber mesh obtained in step d on the template, place it in a hot press, press it at 70°C and 5 MPa for 5 seconds, and demold it after natural cooling to form a micron-scale protrusion structure on the surface.

[0029] Preparation of modified nano-silica: 5 g of nano-silica was added to 200 mL of an ethanol-water mixed solvent (volume ratio 3:1) and ultrasonically dispersed for 30 minutes; 8 g of γ-glycidyloxypropyltrimethoxysilane was added, the pH was adjusted to 4-5 with glacial acetic acid, and the mixture was stirred at 60°C for 4 hours. The mixture was centrifuged, washed, and dried to obtain epoxidized nano-silica; 3 g of dodecyldimethylaminopropylammonium chloride was dissolved in 150 mL of deionized water, the epoxidized nano-silica was added, the mixture was stirred at 70°C for 6 hours, and the mixture was centrifuged, washed, and dried to obtain modified nano-silica.

[0030] The modified nano-silica was prepared into a 0.5wt% ethanol suspension and evenly sprayed on the surface of the fiber web using an electrostatic spraying device (voltage 15kV, flow rate 10mL / min, nozzle 15cm away from the fiber web) (the spraying amount was 10% of the fiber web mass), and dried in a 60℃ oven for 10 minutes to obtain a cotton wipe base.

[0031] Step f: Weigh 9 parts peach gum polysaccharide, 4 parts collagen, 2.5 parts sodium hyaluronate, and 2.5 parts glycerin by weight, add 88 parts deionized water, and stir until completely dissolved to prepare an essence. The essence is evenly sprayed onto the surface of the cotton wipes obtained in step e using a sprayer (the spraying amount is 15% of the substrate's mass). The wipes are then dried in a vacuum drying oven at 40°C and -0.09 MPa for 2 hours. The dried material is cut into pieces using a slitter and sterilized by irradiation to obtain the finished biodegradable cotton wipes. Example 2 A method for preparing a degradable cotton wipe comprises the following steps: Step a: Weigh 500g of Egyptian long-staple cotton fiber and place it in 5000mL of a 3wt% sodium hydroxide aqueous solution in a 55°C water bath with stirring for 15 minutes (stirring at 200rpm). After treatment, rinse the fiber repeatedly with deionized water until the pH of the washing solution reaches 7.0±0.2. Immerse the alkali-treated cotton fiber in a cellulase solution (enzyme activity 2000U / g, fiber to solution mass volume ratio 1:10) prepared in acetate buffer at pH 4.8. Enzymatic hydrolysis is carried out in a shaking water bath at 45°C (150rpm) for 30 minutes. Immediately after the enzymatic hydrolysis, the system is heated to 80°C and maintained for 10 minutes to inactivate the enzyme. Filter the pretreated cotton fiber and place it in a well-ventilated area to drain for later use.

[0032] Step b: Weigh 200g of polycaprolactone fiber (1.5 dtex), lay it flat in a hot air oven, and preheat it at 88°C for 8 minutes. Secure the preheated fiber to a stretching device and stretch it to 2.3 times its original length at a constant rate of 10mm / min. Immediately after stretching, blow it with cold air to room temperature to set the shape. This yields pretreated polycaprolactone fiber, which should be sealed and stored to protect from moisture.

[0033] Step c: Mix the pretreated cotton fiber and pretreated polycaprolactone fiber in a mass ratio of 10:4 (total weight 700g), place them in an opener with a card cloth spacing of 0.5mm and open them three times to ensure that the fibers are evenly mixed. The opened mixed fiber is sent to the air-laid machine with an operating pressure of 0.6MPa, an ambient temperature of 25±1℃, a relative humidity of 60±5%, and a gram weight of 50±2g / m 2 The fiber web should be made of a uniform fiber web with a coefficient of variation of ≤8%. Immediately after forming the web, pre-press it with a 0.5MPa pressure roller for 30 seconds to enhance the bonding strength between fibers.

[0034] Step d: Prepare the main network solution: weigh 25 g of carboxymethyl chitosan (88% deacetylation degree) and 12 g of oxidized cellulose nanofibrils (30 nm in diameter), add them together into 460 mL of deionized water, and stir at 50°C for 2 hours until they are completely dissolved to form a uniform viscous solution.

[0035] Prepare the auxiliary network dispersion: Add 500 mL of deionized water to a beaker, weigh 5 g of hyaluronic acid powder, and stir at 200 rpm using a magnetic stirrer for 30 minutes until the hyaluronic acid is completely dissolved. Next, slowly add 1 mol / L sodium hydroxide solution dropwise, checking the pH with pH paper, to adjust the solution to 8.5-9.0. Slowly add 2 g of 1,4-butanediol diglycidyl ether to the solution while increasing the stirring speed to 300 rpm. Place the beaker in a 40°C water bath and continue stirring for 6 hours. After the reaction is complete, transfer the mixture to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes. Discard the supernatant. Wash the precipitate three times with deionized water, centrifuging again after each wash. The washed precipitate was placed in a freeze dryer, pre-frozen at -40°C for 2 hours, and then freeze-dried at a vacuum degree of ≤10 Pa for 12 hours to obtain a hyaluronic acid cross-linked product.

[0036] Weigh 20g of calcium alginate gel microspheres (particle size 30μm) and 9g of hyaluronic acid crosslinker, add them to 300mL of deionized water, and treat them using a 40kHz, 300W ultrasonic device for 15 minutes until uniformly dispersed. The fiber web obtained in step c was first passed through an auxiliary network dispersion solution immersion tank at a speed of 2m / min (immersion time 60 seconds), dehydrated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 2 minutes. The fiber web was then passed through a main network solution immersion tank at the same speed (immersion time 30 seconds), dehydrated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 3 minutes to obtain a water-absorbent fiber web.

[0037] Step e: Select a nickel template with a hexagonal protrusion array with a height of 30 μm and a spacing of 80 μm, spread the absorbent fiber mesh obtained in step d on the template, place it in a hot press, press it at 70°C and 5 MPa for 5 seconds, and demold it after natural cooling to form a micron-scale protrusion structure on the surface.

[0038] Preparation of modified nano-silica: 5 g of nano-silica was added to 200 mL of an ethanol-water mixed solvent (volume ratio 3:1) and ultrasonically dispersed for 30 minutes; 8 g of γ-glycidyloxypropyltrimethoxysilane was added, the pH was adjusted to 4-5 with glacial acetic acid, and the mixture was stirred at 60°C for 4 hours. The mixture was centrifuged, washed, and dried to obtain epoxidized nano-silica; 3 g of dodecyldimethylaminopropylammonium chloride was dissolved in 150 mL of deionized water, the epoxidized nano-silica was added, the mixture was stirred at 70°C for 6 hours, and the mixture was centrifuged, washed, and dried to obtain modified nano-silica.

[0039] The modified nano-silica was prepared into a 0.5wt% ethanol suspension and evenly sprayed on the surface of the fiber web using an electrostatic spraying device (voltage 15kV, flow rate 10mL / min, nozzle 15cm away from the fiber web) (the spraying amount was 10% of the fiber web mass), and dried in a 60℃ oven for 10 minutes to obtain a cotton wipe base.

[0040] Step f: Weigh 6 parts peach gum polysaccharide, 3 parts collagen, 1.5 parts sodium hyaluronate, and 1.5 parts glycerin by weight, add 83 parts deionized water, and stir until completely dissolved to prepare an essence. The essence is evenly sprayed onto the surface of the cotton wipes obtained in step e using a sprayer (the spraying amount is 15% of the substrate's mass). The wipes are then dried in a vacuum drying oven at 40°C and -0.09 MPa for 2 hours. The dried material is cut into pieces using a slitter and sterilized by irradiation to obtain the finished biodegradable cotton wipes.

[0041] Example 3 A method for preparing a degradable cotton wipe comprises the following steps: Step a: Weigh 500g of Egyptian long-staple cotton fiber and place it in 5000mL of a 3wt% sodium hydroxide aqueous solution in a 55°C water bath with stirring for 15 minutes (stirring at 200rpm). After treatment, rinse the fiber repeatedly with deionized water until the pH of the washing solution reaches 7.0±0.2. Immerse the alkali-treated cotton fiber in a cellulase solution (enzyme activity 2000U / g, fiber to solution mass volume ratio 1:10) prepared in acetate buffer at pH 4.8. Enzymatic hydrolysis is carried out in a shaking water bath at 45°C (150rpm) for 30 minutes. Immediately after the enzymatic hydrolysis, the system is heated to 80°C and maintained for 10 minutes to inactivate the enzyme. Filter the pretreated cotton fiber and place it in a well-ventilated area to drain for later use.

[0042] Step b: Weigh 200g of polycaprolactone fiber (1.5 dtex), lay it flat in a hot air oven, and preheat it at 88°C for 8 minutes. Secure the preheated fiber to a stretching device and stretch it to 2.5 times its original length at a constant rate of 10mm / min. Immediately after stretching, blow it with cold air to room temperature to set the shape. This yields pretreated polycaprolactone fiber, which should be sealed and stored to protect from moisture.

[0043] Step c: Mix the pretreated cotton fiber and pretreated polycaprolactone fiber in a mass ratio of 10:5 (total weight 700g), place them in an opener with a card cloth spacing of 0.5mm and open them three times to ensure that the fibers are evenly mixed. The opened mixed fiber is sent to the air-laid machine with an operating pressure of 0.6MPa, an ambient temperature of 25±1℃, and a relative humidity of 60±5%. The prepared weight is 50±2g / m 2 The fiber web should be made of a uniform fiber web with a coefficient of variation of ≤8%. Immediately after forming the web, pre-press it with a 0.5MPa pressure roller for 30 seconds to enhance the bonding strength between fibers.

[0044] Step d: Prepare the main network solution: weigh 25 g of carboxymethyl chitosan (88% deacetylation degree) and 15 g of oxidized cellulose nanofibrils (30 nm in diameter), add them together into 460 mL of deionized water, and stir at 50°C for 2 hours until they are completely dissolved to form a uniform viscous solution.

[0045] Prepare the auxiliary network dispersion: Add 500 mL of deionized water to a beaker, weigh 5 g of hyaluronic acid powder, and stir at 200 rpm using a magnetic stirrer for 30 minutes until the hyaluronic acid is completely dissolved. Next, slowly add 1 mol / L sodium hydroxide solution dropwise, checking the pH with pH paper, to adjust the solution to 8.5-9.0. Slowly add 2 g of 1,4-butanediol diglycidyl ether to the solution while increasing the stirring speed to 300 rpm. Place the beaker in a 40°C water bath and continue stirring for 6 hours. After the reaction is complete, transfer the mixture to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes. Discard the supernatant. Wash the precipitate three times with deionized water, centrifuging again after each wash. The washed precipitate was placed in a freeze dryer, pre-frozen at -40°C for 2 hours, and then freeze-dried at a vacuum degree of ≤10 Pa for 12 hours to obtain a hyaluronic acid cross-linked product.

[0046] Weigh 20g of calcium alginate gel microspheres (particle size 30μm) and 10g of cross-linked hyaluronic acid, add them to 300mL of deionized water, and treat them using a 40kHz, 300W ultrasonic device for 15 minutes until uniformly dispersed. The fiber web obtained in step c was first passed through an auxiliary network dispersion solution immersion tank at a speed of 2m / min (immersion time 60 seconds), dehydrated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 2 minutes. The fiber web was then passed through a main network solution immersion tank at the same speed (immersion time 30 seconds), dehydrated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 3 minutes to obtain a water-absorbent fiber web.

[0047] Step e: Select a nickel template with a hexagonal protrusion array with a height of 30 μm and a spacing of 80 μm, spread the absorbent fiber mesh obtained in step d on the template, place it in a hot press, press it at 70°C and 5 MPa for 5 seconds, and demold it after natural cooling to form a micron-scale protrusion structure on the surface.

[0048] Preparation of modified nano-silica: 5 g of nano-silica was added to 200 mL of an ethanol-water mixed solvent (volume ratio 3:1) and ultrasonically dispersed for 30 minutes; 8 g of γ-glycidyloxypropyltrimethoxysilane was added, the pH was adjusted to 4-5 with glacial acetic acid, and the mixture was stirred at 60°C for 4 hours. The mixture was centrifuged, washed, and dried to obtain epoxidized nano-silica; 3 g of dodecyldimethylaminopropylammonium chloride was dissolved in 150 mL of deionized water, the epoxidized nano-silica was added, the mixture was stirred at 70°C for 6 hours, and the mixture was centrifuged, washed, and dried to obtain modified nano-silica.

[0049] The modified nano-silica was prepared into a 0.5wt% ethanol suspension and evenly sprayed on the surface of the fiber web using an electrostatic spraying device (voltage 15kV, flow rate 10mL / min, nozzle 15cm away from the fiber web) (the spraying amount was 10% of the fiber web mass), and dried in a 60℃ oven for 10 minutes to obtain a cotton wipe base.

[0050] Step f: Weigh 7 parts peach gum polysaccharide, 3.5 parts collagen, 2 parts sodium hyaluronate, and 2 parts glycerin by weight, add 85 parts deionized water, and stir until completely dissolved to prepare an essence. The essence is evenly sprayed onto the surface of the cotton wipes obtained in step e using a sprayer (the spraying amount is 15% of the substrate's mass). The wipes are then dried in a vacuum drying oven at 40°C and -0.09 MPa for 2 hours. The dried material is cut into pieces using a slitter and sterilized by irradiation to obtain the finished biodegradable cotton wipes.

[0051] Example 4 A method for preparing a degradable cotton wipe comprises the following steps: Step a: Weigh 500g of Egyptian long-staple cotton fiber and place it in 5000mL of a 5wt% sodium hydroxide aqueous solution in a 60°C water bath with stirring for 20 minutes (stirring at 200rpm). After treatment, rinse the fiber repeatedly with deionized water until the pH of the washing solution reaches 7.0±0.2. Immerse the alkali-treated cotton fiber in a cellulase solution (enzyme activity 2000U / g, fiber to solution mass volume ratio 1:10) prepared in acetate buffer at pH 4.8. Enzyme hydrolysis is carried out in a shaking water bath at 45°C (150rpm) for 30 minutes. Immediately after the enzymatic hydrolysis, the system is heated to 80°C and maintained for 10 minutes to inactivate the enzyme. Filter the pretreated cotton fiber and place it in a well-ventilated area to drain for later use.

[0052] Step b: Weigh 200g of polycaprolactone fiber (1.5 dtex), lay it flat in a hot air oven, and preheat it at 90°C for 10 minutes. Secure the preheated fiber to a stretching device and stretch it to three times its original length at a constant rate of 10mm / min. Immediately after stretching, blow it with cold air to room temperature to set the shape. This yields pretreated polycaprolactone fiber, which should be sealed and stored to protect from moisture.

[0053] Step c: Mix the pretreated cotton fiber and pretreated polycaprolactone fiber in a mass ratio of 10:7 (total weight 700g), place them in an opener with a card cloth spacing of 0.5mm and open them three times to ensure that the fibers are evenly mixed. The opened mixed fiber is sent to the air-laid machine with an operating pressure of 0.6MPa, an ambient temperature of 25±1℃, a relative humidity of 60±5%, and a gram weight of 50±2g / m 2 The fiber web should be made of a uniform fiber web with a coefficient of variation of ≤8%. Immediately after forming the web, pre-press it with a 0.5MPa pressure roller for 30 seconds to enhance the bonding strength between fibers.

[0054] Step d: Prepare the main network solution: weigh 25 g of carboxymethyl chitosan (88% deacetylation degree) and 20 g of oxidized cellulose nanofibrils (30 nm in diameter), add them together into 460 mL of deionized water, and stir at 50 °C for 2 h until they are completely dissolved to form a uniform viscous solution.

[0055] Prepare the auxiliary network dispersion: Add 500 mL of deionized water to a beaker, weigh 5 g of hyaluronic acid powder, and stir at 200 rpm using a magnetic stirrer for 30 minutes until the hyaluronic acid is completely dissolved. Next, slowly add 1 mol / L sodium hydroxide solution dropwise, checking the pH with pH paper, to adjust the solution to 8.5-9.0. Slowly add 2 g of 1,4-butanediol diglycidyl ether to the solution while increasing the stirring speed to 300 rpm. Place the beaker in a 40°C water bath and continue stirring for 6 hours. After the reaction is complete, transfer the mixture to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes. Discard the supernatant. Wash the precipitate three times with deionized water, centrifuging again after each wash. The washed precipitate was placed in a freeze dryer, pre-frozen at -40°C for 2 hours, and then freeze-dried at a vacuum degree of ≤10 Pa for 12 hours to obtain a hyaluronic acid cross-linked product.

[0056] Weigh 20g of calcium alginate gel microspheres (particle size 30μm) and 12g of cross-linked hyaluronic acid, add them to 300mL of deionized water, and treat them using a 40kHz, 300W ultrasonic device for 15 minutes until uniformly dispersed. The fiber web obtained in step c was first passed through an auxiliary network dispersion solution immersion tank at a speed of 2m / min (immersion time 60 seconds), de-liquidated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 2 minutes. The fiber web was then passed through a main network solution immersion tank at the same speed (immersion time 30 seconds), de-liquidated with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 3 minutes to obtain a water-absorbent fiber web.

[0057] Step e: Select a nickel template with a hexagonal protrusion array with a height of 30 μm and a spacing of 80 μm, spread the absorbent fiber mesh obtained in step d on the template, place it in a hot press, press it at 70°C and 5 MPa for 5 seconds, and demold it after natural cooling to form a micron-scale protrusion structure on the surface.

[0058] Preparation of modified nano-silica: 5 g of nano-silica was added to 200 mL of an ethanol-water mixed solvent (volume ratio 3:1) and ultrasonically dispersed for 30 minutes; 8 g of γ-glycidyloxypropyltrimethoxysilane was added, the pH was adjusted to 4-5 with glacial acetic acid, and the mixture was stirred at 60°C for 4 hours. The mixture was centrifuged, washed, and dried to obtain epoxidized nano-silica; 3 g of dodecyldimethylaminopropylammonium chloride was dissolved in 150 mL of deionized water, the epoxidized nano-silica was added, the mixture was stirred at 70°C for 6 hours, and the mixture was centrifuged, washed, and dried to obtain modified nano-silica.

[0059] The modified nano-silica was prepared into a 0.5wt% ethanol suspension and evenly sprayed on the surface of the fiber web using an electrostatic spraying device (voltage 15kV, flow rate 10mL / min, nozzle 15cm away from the fiber web) (the spraying amount was 10% of the fiber web mass), and dried in a 60℃ oven for 10 minutes to obtain a cotton wipe base.

[0060] Step f: Weigh 10 parts peach gum polysaccharide, 5 parts collagen, 3 parts sodium hyaluronate, and 3 parts glycerin by weight, add 90 parts deionized water, and stir until completely dissolved to prepare an essence. The essence is evenly sprayed onto the surface of the cotton wipes obtained in step e using a sprayer (the spraying amount is 15% of the substrate's mass). The wipes are then dried in a vacuum drying oven at 40°C and -0.09 MPa for 2 hours. The dried material is cut into pieces using a slitter and sterilized by irradiation to obtain the finished biodegradable cotton wipes. Example 5 A method for preparing a degradable cotton wipe comprises the following steps: Step a: Weigh 500g of Egyptian long-staple cotton fiber and place it in 5000mL of a 2wt% sodium hydroxide aqueous solution in a 50°C water bath with stirring for 10 minutes (stirring at 200rpm). After treatment, rinse the fiber repeatedly with deionized water until the pH of the washing solution reaches 7.0±0.2. Immerse the alkali-treated cotton fiber in a cellulase solution (enzyme activity 2000U / g, fiber to solution mass volume ratio 1:10) prepared in acetate buffer at pH 4.8. Enzyme hydrolysis is carried out in a shaking water bath at 45°C (150rpm) for 30 minutes. Immediately after the enzymatic hydrolysis, the system is heated to 80°C and maintained for 10 minutes to inactivate the enzyme. Filter the pretreated cotton fiber and place it in a well-ventilated area to drain for later use.

[0061] Step b: Weigh 200g of polycaprolactone fiber (1.5 dtex), lay it flat in a hot air oven, and preheat it at 85°C for 5 minutes. Secure the preheated fiber to a stretching device and stretch it to twice its original length at a constant rate of 10mm / min. Immediately after stretching, blow it with cold air to room temperature to set the shape. This yields pretreated polycaprolactone fiber, which should be sealed and stored to protect from moisture.

[0062] Step c: Mix the pretreated cotton fiber and pretreated polycaprolactone fiber in a mass ratio of 10:3 (total weight 700g), place them in an opener with a card cloth spacing of 0.5mm and open them three times to ensure that the fibers are evenly mixed. The opened mixed fiber is sent to the air-laid machine with an operating pressure of 0.6MPa, an ambient temperature of 25±1℃, and a relative humidity of 60±5%. The prepared weight is 50±2g / m 2 The fiber web should be made of a uniform fiber web with a coefficient of variation of ≤8%. Immediately after forming the web, pre-press it with a 0.5MPa pressure roller for 30 seconds to enhance the bonding strength between fibers.

[0063] Step d: Prepare the main network solution: weigh 25 g of carboxymethyl chitosan (88% deacetylation degree) and 10 g of oxidized cellulose nanofibrils (30 nm in diameter), add them together into 460 mL of deionized water, and stir at 50°C for 2 hours until they are completely dissolved to form a uniform viscous solution.

[0064] Prepare the auxiliary network dispersion: Add 500 mL of deionized water to a beaker, weigh 5 g of hyaluronic acid powder, and stir at 200 rpm using a magnetic stirrer for 30 minutes until the hyaluronic acid is completely dissolved. Next, slowly add 1 mol / L sodium hydroxide solution dropwise, checking the pH with pH paper, to adjust the solution to 8.5-9.0. Slowly add 2 g of 1,4-butanediol diglycidyl ether to the solution while increasing the stirring speed to 300 rpm. Place the beaker in a 40°C water bath and continue stirring for 6 hours. After the reaction is complete, transfer the mixture to a centrifuge tube and centrifuge at 8000 rpm for 15 minutes. Discard the supernatant. Wash the precipitate three times with deionized water, centrifuging again after each wash. The washed precipitate was placed in a freeze dryer, pre-frozen at -40°C for 2 hours, and then freeze-dried at a vacuum degree of ≤10 Pa for 12 hours to obtain a hyaluronic acid cross-linked product.

[0065] Weigh 20g of calcium alginate gel microspheres (particle size 30μm) and 8g of hyaluronic acid crosslinker, add them to 300mL of deionized water, and treat them using a 40kHz, 300W ultrasonic device for 15 minutes until uniformly dispersed. The fiber web obtained in step c was first passed through an auxiliary network dispersion solution immersion tank at a speed of 2m / min (immersion time 60 seconds), de-liquided with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 2 minutes. The fiber web was then passed through a main network solution immersion tank at the same speed (immersion time 30 seconds), de-liquided with a 0.2MPa roller, and then dried in a 60°C hot air dryer for 3 minutes to obtain a water-absorbent fiber web.

[0066] Step e: Select a nickel template with a hexagonal protrusion array with a height of 30 μm and a spacing of 80 μm, spread the absorbent fiber mesh obtained in step d on the template, place it in a hot press, press it at 70°C and 5 MPa for 5 seconds, and demold it after natural cooling to form a micron-scale protrusion structure on the surface.

[0067] Preparation of modified nano-silica: 5 g of nano-silica was added to 200 mL of an ethanol-water mixed solvent (volume ratio 3:1) and ultrasonically dispersed for 30 minutes; 8 g of γ-glycidyloxypropyltrimethoxysilane was added, the pH was adjusted to 4-5 with glacial acetic acid, and the mixture was stirred at 60°C for 4 hours. The mixture was centrifuged, washed, and dried to obtain epoxidized nano-silica; 3 g of dodecyldimethylaminopropylammonium chloride was dissolved in 150 mL of deionized water, the epoxidized nano-silica was added, the mixture was stirred at 70°C for 6 hours, and the mixture was centrifuged, washed, and dried to obtain modified nano-silica.

[0068] The modified nano-silica was prepared into a 0.5wt% ethanol suspension and evenly sprayed on the surface of the fiber web using an electrostatic spraying device (voltage 15kV, flow rate 10mL / min, nozzle 15cm away from the fiber web) (the spraying amount was 10% of the fiber web mass), and dried in a 60℃ oven for 10 minutes to obtain a cotton wipe base.

[0069] Step f: Weigh 5 parts peach gum polysaccharide, 2 parts collagen, 1 part sodium hyaluronate, and 1 part glycerin by weight, add 80 parts deionized water, and stir until completely dissolved to prepare an essence. Use a sprayer to evenly spray the essence onto the surface of the cotton wipes obtained in step e (the amount applied is 15% of the substrate's mass). Then, place the essence in a vacuum drying oven and dry it at 40°C and -0.09 MPa for 2 hours. The dried material is cut into pieces using a slitter and sterilized by irradiation to obtain the finished biodegradable cotton wipes.

[0070] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that step a and step b are omitted, that is, the cotton fiber and the polycaprolactone fiber are not pretreated.

[0071] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that step d is omitted, that is, the fiber web is not impregnated with the main network solution and the auxiliary network dispersion.

[0072] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that step e is omitted, that is, the micro-nano raised rough structure is not formed on the surface of the fiber web.

[0073] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the modified nano-silica in step e is replaced by ordinary nano-silica.

[0074] Performance testing: 1. Biodegradation Test: According to GB / T 19277.1-2011, 5g of shredded cotton wipes were mixed with 50g of humus soil. Deionized water was added to adjust the moisture content to 60%. The mixture was incubated in a 25°C incubator in the dark for 60 days. After incubation, the mixture was filtered through a 200-mesh sieve, and the undegraded residue was collected and dried to a constant weight (m0). The biodegradation rate was calculated using the formula: Biodegradation rate (%) = (5 - m0) / 5 × 100%. Each sample was tested three times, and the average value was calculated. The test results are shown in Table 1.

[0075] 2. Water Absorption Rate Test: Take a cotton wipe sample, cut it into a 10 cm x 10 cm square specimen, and weigh its initial mass (m0). Place the specimen horizontally under a 5 cm diameter glass funnel. Add deionized water at a constant rate of 5 mL / min through the funnel onto the specimen surface. Record the time it takes for the specimen to completely absorb water and no longer seep water (t). Simultaneously, weigh the mass of the specimen after water absorption (m1). Calculate the water absorption rate using the formula: Water absorption rate (g / s) = (m1 - m0) / t. Test each sample three times and take the average value. See Table 1 for test results.

[0076] 3. Maximum Water Absorption Test: Using the centrifugation method, a 10 cm x 10 cm sample with an initial mass of m0 was immersed in deionized water for 30 minutes until fully swollen. The sample was removed with tweezers and suspended for 30 seconds to drain any surface moisture. The sample was then placed in a centrifuge tube and centrifuged at 3000 rpm for 10 minutes. The post-centrifugation mass (m2) was measured. Maximum water absorption was calculated using the formula: Maximum water absorption (g / g) = (m2 - m0) / m0. Each sample was tested three times, and the average value was calculated. The test results are shown in Table 1.

[0077] 4. Water Retention Test: After saturation with water and centrifugation, place the sample (mass m1) in an environment with a temperature of 25°C and a relative humidity of 60% for 2 hours. Weigh the post-storage mass (m2). Calculate the water retention rate using the formula: Water Retention (%) = (m2 / m1) × 100%. Test each sample three times and take the average value. See Table 1 for test results.

[0078] 5. Surface Contact Angle Measurement: Using a contact angle meter, drop 5 μL of deionized water onto the surface of a cotton towel. After 10 seconds, capture an image and calculate the contact angle. Test the surface five times at different locations on the sample and take the average value. A smaller contact angle indicates a more hydrophilic surface. See Table 1 for test results.

[0079] Table 1: Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a degradable cotton soft towel, characterized in that: The following steps are involved: a) using Egyptian long-staple cotton fiber as raw material, first placing it in a sodium hydroxide aqueous solution for alkaline treatment, then repeatedly washing it with deionized water until it is neutral; then immersing the cotton fiber in a cellulase solution prepared with an acetate buffer for enzymatic hydrolysis, and heating and inactivating it after the enzymatic hydrolysis to obtain pretreated cotton fiber; b) using polycaprolactone fiber as raw material, placing it in a hot air oven for preheating, stretching it at a constant stretching rate, and then immediately cooling it to set it, thereby obtaining pretreated polycaprolactone fiber; c) mixing the pretreated cotton fibers and the pretreated polycaprolactone fibers, opening the fibers with a card cloth opener, and forming a fiber web with an air-laid machine; d) preparing a primary network solution by dissolving carboxymethyl chitosan and oxidized cellulose nanofibrils in deionized water; then preparing an auxiliary network dispersion by dispersing calcium alginate gel microspheres and hyaluronic acid crosslinkers in deionized water and ultrasonically treating the dispersion; and sequentially immersing the fiber web obtained in step c) in the auxiliary network solution, removing the liquid by a roller, and drying the fiber web, and then immersing the primary network solution, removing the liquid by a roller, and drying the fiber web, thereby constructing a super absorbent network within the fiber web to obtain a water-absorbent fiber web; e) Using a nickel template with a hexagonal protrusion array, the web is placed in a hot press and pressed, followed by natural cooling and demolding to form a micron-scale protrusion structure on the surface. Nano-silica is then prepared into an ethanol suspension and evenly sprayed onto the surface of the absorbent web using an electrostatic sprayer. The web is then dried to obtain a cotton wipe substrate. f) Spray the essence onto the cotton towel base, then vacuum dry it, and finally cut it and sterilize it by irradiation.

2. The method for preparing a degradable cotton wipe according to claim 1, characterized in that: In the step a), the concentration of the sodium hydroxide solution is 2-5 wt %, the alkali treatment temperature is 50-60° C., and the alkali treatment time is 10-20 min.

3. The method for preparing a degradable cotton wipe according to claim 1, characterized in that: In the step b), the polycaprolactone fiber is preheated at a temperature of 85 to 90° C. for 5 to 10 minutes and stretched 2 to 3 times.

4. The method for preparing a degradable cotton wipe according to claim 1, characterized in that: In the step c), the mass ratio of the pretreated cotton fiber to the pretreated polycaprolactone fiber is 10:3-7.

5. The method for preparing a degradable cotton wipe according to claim 1, characterized in that: In the step d), the mass ratio of carboxymethyl chitosan to oxidized cellulose nanofibrils is 5:2-4.

6. The method for preparing a degradable cotton wipe according to claim 1, characterized in that: In the step d), the mass ratio of calcium alginate gel microspheres to hyaluronic acid cross-linked body is 10:4-6.

7. The method for preparing a degradable cotton wipe according to claim 6, characterized in that: The preparation method of the cross-linked hyaluronic acid comprises the following steps: The hyaluronic acid powder is added to deionized water and stirred to dissolve, and then sodium hydroxide solution is added to adjust the pH to 8.5-9.0, and then 1,4-butanediol diglycidyl ether is added, heated and stirred to react, and washed and freeze-dried to obtain a hyaluronic acid cross-linked body.

8. The method for preparing a degradable cotton wipe according to claim 1, characterized in that: In the step e), the nano-silicon dioxide is modified, which includes the following steps: The nano-silica is added to a mixed solvent of ethanol and water, and dispersed uniformly by ultrasonic oscillation. Then, γ-glycidyloxypropyltrimethoxysilane is added, and the pH is adjusted to 4-5. The mixture is heated and stirred for reaction, and the mixture is centrifuged, washed, and dried to obtain epoxidized nano-silica. Add dodecyldimethylaminopropylammonium chloride into deionized water, stir and dissolve, then add epoxidized nano-silica, heat and stir to react, and then centrifuge, wash and dry to obtain the product.

9. The method for preparing a degradable cotton wipe according to claim 1, characterized in that: In step f), the essence comprises the following components in parts by weight: 5-10 parts of peach gum polysaccharide, 2-5 parts of collagen, 1-3 parts of sodium hyaluronate, 1-3 parts of glycerin, and 80-90 parts of deionized water.

10. A degradable cotton soft towel, characterized in that: The product is prepared by the method described in any one of claims 1 to 9 above.

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