Slow-release mask cloth based on onion extract and preparation method thereof

Abstract

The invention relates to the technical field of mask cloth, and discloses onion extract-based slow-release mask cloth, which sequentially comprises a bottom layer non-woven fabric, an onion extract embedded fiber layer and a polylactic acid nanofiber layer, and the bottom layer non-woven fabric, the onion extract embedded fiber layer and the polylactic acid nanofiber layer are compounded through spunlace. The invention discloses a preparation method of slow-release antibacterial mask cloth based on onion extract. The preparation method comprises the following steps: s1, preparing a bottom-layer non-woven fabric; s2, preparing an onion extract embedded fiber layer; s3, preparing a polylactic acid nanofiber layer; and s4, performing hot rolling on the three fiber layers, performing spunlace compounding, and performing drying so as to obtain the mask cloth. The prepared mask cloth has the effects of resisting bacteria, resisting oxidation and whitening skin, and the onion extract is long in slow release time.

Description

Technical Field

[0001] The present invention relates to the technical field of facial mask fabrics, and in particular to a slow-release facial mask fabric based on onion extract and a preparation method thereof. Background Art

[0002] A facial mask fabric is a common carrier for facial mask essence, and it is usually made of non-woven fabric. At present, the facial mask fabric itself does not have the function of skin care. It usually needs to be used in combination with facial mask essence, that is, after the facial mask fabric absorbs the facial mask essence, it is applied on the skin surface, and the functions of nourishing the skin, moisturizing the skin, whitening the skin, etc. are realized through the facial mask essence; if the facial mask fabric is directly moistened with water and then pasted on the skin surface (that is, using water to replace the facial mask essence), the facial mask fabric without the facial mask essence does not have the effects of nourishing the skin, moisturizing, whitening, etc. That is, the facial mask fabric is only a carrier for the facial mask essence, and the facial mask fabric itself does not have any skin care effects. The effect of the facial mask completely depends on the facial mask essence. The existing facial mask fabric has a relatively single function and only serves as a carrier for the facial mask essence, and it lacks the role of skin care itself. Summary of the Invention

[0003] In order to solve the above problems existing in the prior art, the present invention provides a slow-release facial mask fabric based on onion extract and a preparation method thereof. This kind of facial mask fabric can be directly used after being moistened with water, and has good effects of antioxidant, antibacterial, oil control and skin whitening; when used in combination with facial mask essence, it can promote the uniform distribution of the essence and improve the utilization efficiency of the essence.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: A slow-release facial mask fabric based on onion extract, successively including a bottom non-woven fabric, an onion extract-embedded fiber layer, and a polylactic acid nanofiber layer. The bottom non-woven fabric, the onion extract-embedded fiber layer, and the polylactic acid nanofiber layer are hydrospun and compounded.

[0005] By adopting the above technical solution: A three-layer structure is adopted. The middle layer is an onion extract-embedded fiber layer, that is, the onion extract is embedded in other fibers and directly applied to the human skin after being moistened with water. The polylactic acid nanofiber layer is in contact with the skin; the onion extract-embedded fiber layer is isolated by the polylactic acid nanofiber layer and does not directly contact the skin. The onion extract in the onion extract-embedded fiber layer is slowly released and acts on the skin through the polylactic acid nanofiber layer, enabling a longer sustained release. On the one hand, it prolongs the continuous skin care of the mask cloth, and on the other hand, it reduces the irritation of the onion extract to the skin. At the same time, the polylactic acid nanofiber layer adopts a nanofilm structure, which can enhance the interaction between the onion extract and the skin; the onion extract is rich in antioxidant components such as quercetin, polyphenolic compounds, and vitamins C / E, which can effectively scavenge free radicals and slow down skin oxidative damage. At the same time, quercetin in the onion extract can inhibit the activity of tyrosinase and block the melanin production pathway, while vitamin C fades existing age spots through a reduction effect; the onion extract contains allicin derivatives, which have broad-spectrum antibacterial properties and can inhibit common acne-causing bacteria such as Staphylococcus aureus and regulate sebum secretion; the polysaccharide substances in the onion extract have strong water absorption, can increase the liquid-carrying capacity of the mask cloth, and can better form a long-acting moisturizing network when used in combination with the mask essence to moisturize the skin.

[0006] A preparation method of a sustained-release antibacterial mask cloth based on onion extract, comprising the following steps: S1. Prepare the bottom non-woven fabric: The fiber main material is mixed, opened, and then carded into a web, and then hot-rolled to prepare the bottom non-woven fabric; S2. Prepare the onion extract-embedded fiber layer: S2-1: Mix the powdery onion extract with an emulsifier, and prepare an onion extract nanoemulsion through high-pressure homogenization; S2-2: Adopt the melt-blown process to spray polypropylene as the polymer melt on the surface of the bottom non-woven fabric, and at the same time spray the onion extract nanoemulsion onto the same surface of the bottom non-woven fabric through a side injection system, so that the onion nanoemulsion is embedded in the polypropylene fiber to obtain an onion extract-embedded fiber layer with a fiber diameter of 2-5 μm; S3. Polylactic acid nanofiber layer: S3-1: Dissolve the polylactic acid particles in a solvent to obtain a polylactic acid solution with a concentration of 12-18% (w / v); S3-2: Prepare a polylactic acid nanofiber layer with a fiber diameter of 300-1200 nm on the surface of the onion extract-embedded fiber layer through the electrospinning process; S4. Hot-roll and hydroentangle the above three fiber layers, and dry them to obtain the mask cloth.

[0007] By adopting the above technical solution: The melt-blown process is used to embed the onion extract nanoemulsion into the polypropylene fiber to form an onion extract-embedded fiber layer, and a polylactic acid nanofiber layer is prepared on the surface of the onion extract-embedded fiber layer through the electrospinning process. The three layers are hot-rolled and hydroentangled. During the hydroentangling process, the residual reagents (such as emulsifiers, etc.) in the mask cloth can be washed away.

[0008] Preferably, the fiber main material in step s1 is prepared according to the following parts by weight: 15-25 parts of viscose fiber, 2-4 parts of mint fiber, 1-2 parts of blueberry fiber, and 3-5 parts of high-shrinkage polyester fiber.

[0009] By adopting the above technical solution: The bottom non-woven fabric uses viscose fiber as the main fiber, and at the same time adds two plant fibers, mint fiber and blueberry fiber. The menthol in the mint fiber disrupts the ordered arrangement of the lipids in the skin cutin layer, thereby enhancing the transdermal absorption rate of quercetin in the onion extract. At the same time, the mint fiber contains the cool aroma of menthofuran, which forms a stable complex with the volatile sulfides (such as propanethiol) in the onion extract through intermolecular interactions, significantly improving the odor acceptance score of the mask cloth. The polyphenols (such as caffeic acid) in the mint fiber protect the onion quercetin from photooxidative degradation through a hydrogen donation mechanism, increasing the active retention rate of the onion extract; the pectin in the blueberry fiber forms a three-dimensional network structure with the polysaccharide (β-glucan) in the onion extract, further enhancing the liquid-carrying rate of the mask cloth; the high-shrinkage polyester fiber has the characteristic of shrinking as the temperature rises. When the mask cloth is applied to the skin surface, it absorbs the heat of the skin and gradually warms up. The high-shrinkage polyester fiber makes the entire mask cloth more compact through its shrinking characteristic, which is beneficial to lifting the skin.

[0010] Preferably, in step s2-1, the preparation method of the onion extract is as follows: After crushing the onion, it is immersed in a citric acid buffer solution with a pH of 5-5.5, and 0.1-0.3% (w / v) of L-cysteine lyase is added, and it is treated in a microwave at 40-45 °C and 300-350 W for 10-20 min; The primary filtrate is obtained by preliminary filtration with a filter screen, the primary filtrate is filtered through a ceramic membrane gradient to obtain a secondary filtrate, and the secondary filtrate is dehydrated to obtain a powdery onion extract.

[0011] By adopting the above technical solution: The sulfides (such as methyl propyl disulfide and other sulfides) in the onion extract are irritating to the human skin, making some people uncomfortable; the sulfides are converted into non-irritating amino acids by L-cysteine lyase to reduce the irritation of the sulfides in the onion extract to the skin.

[0012] Preferably, in step s2-2, the melt flow index of the polymer melt is formulated to be 80-95 g / 10 min, the extrusion amount of the polymer melt is 0.3-0.6 g / hole / min, the melt blowing die head temperature is 185-192 °C, the air flow injection angle in the melt blowing die head is 40-48°, and the air flow pressure in the melt blowing die head is 0.12-0.25 Mpa; The injection temperature of the lateral injection system is 185-192 °C, and the injection angle is 35-40°; The percentage weight of the onion extract in the prepared onion extract-embedded fiber layer is 8-12%.

[0013] By adopting the above technical solution: By reasonably setting the parameters of the meltblowing process, the onion extract can be comprehensively and stably embedded into the polypropylene fibers.

[0014] Preferably, in step s3-1, polylactic acid particles are first added to DCM solvent until completely dissolved; then DMF solvent is slowly added to the solution at a rate of 1-1.5 mL / min to obtain a polylactic acid solution with a viscosity of 1200-1500 cP.

[0015] By adopting the above technical solution: DCM solvent is dichloromethane. Polylactic acid (PLA) has good solubility in dichloromethane. And during the electrospinning process, dichloromethane can quickly volatilize by heat (boiling point 39.6 °C), which can effectively promote the fiber solidification and forming, prevent fiber adhesion, and at the same time can also reduce the fracture tendency of the spinning solution jet to form continuous and uniform nanofibers; DMF solvent is N,N-dimethylformamide. When mixed with DCM, it can adjust the evaporation rate and dielectric constant of the solution, improve the spinning stability. At the same time, DMF solvent can slow down the ordered arrangement of polylactic acid molecular chains to form amorphous fibers and improve the flexibility of the membrane.

[0016] Preferably, 1-2% (by mass) of powdery onion extract is added to the polylactic acid solution prepared in step s3-1, and a polylactic acid composite solution is obtained by ultrasonic dispersion.

[0017] By adopting the above technical solution: Adding onion extract to the polylactic acid nanofiber layer enhances the loading of onion extract in the facial mask cloth.

[0018] Preferably, in step s3-2, a double-layer coaxial electrospinning process is adopted. The inner layer uses a polylactic acid solution, and the outer layer uses a polyvinyl alcohol solution; the polyvinyl alcohol solution is prepared by dissolving polyvinyl alcohol in deionized water, and the concentration of the polyvinyl alcohol solution is 10-12% (w / v); when the polylactic acid nanofiber layer prepared in step s3-2 undergoes hydroentangling composite in step s4, the polyvinyl alcohol in the polylactic acid nanofiber layer is removed by washing, so that a honeycomb-like pore structure is formed in the polylactic acid nanofiber layer.

[0019] By adopting the above technical solution: It effectively improves the porosity of the polylactic acid nanofiber layer and better mechanical properties, so that the facial mask cloth has better long-term moisturizing and essence slow-release effects.

[0020] Therefore, the present invention has the following beneficial effects: (1) The mask cloth adopts a three-layer structure. The polylactic acid nanofiber layer is gentler in contact with the skin. Its internal honeycomb pore structure can store liquids (liquids containing onion extract or mask essence) more smoothly and diffuse them, effectively improving the skin moisturizing effect; The onion extract-embedded fiber layer can release the onion extract to act on the skin, achieving the effects of antibacterial, antioxidant, and skin whitening; (2) The onion extract-embedded fiber layer uses the melt-blown process to embed the onion extract into polypropylene fibers, thereby achieving long-term slow release and reducing the irritation of the onion extract to the skin; (3) The bottom non-woven fabric contains mint fibers and blueberry fibers. The synergistic effect between the mint fibers, blueberry fibers and the onion extract improves the liquid loading rate of the mask cloth, the absorption rate of the onion extract by the skin, and the active retention rate of the onion extract; (4) The polylactic acid nanofiber layer adopts a honeycomb multi-pore structure, enabling the onion extract (or mask essence) to be better absorbed by the skin; (5) Finally, hydrospun lamination is used to wash away various solvents or reagents remaining in the mask cloth during the hydrospun process, making the mask cloth safer to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a schematic structural diagram of a mask cloth.

[0022] In the figure: bottom non-woven fabric 1, onion extract-embedded fiber layer 2, polylactic acid nanofiber layer 3. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to make the technical problems to be solved, technical solutions and beneficial technical effects of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and multiple exemplary embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the protection scope of the present invention.

[0024] As Figure 1 shown, a slow-release antibacterial mask cloth based on onion extract sequentially includes a bottom non-woven fabric 1, an onion extract-embedded fiber layer 2, and a polylactic acid nanofiber layer 3. The bottom non-woven fabric 1, the onion extract-embedded fiber layer 2, and the polylactic acid nanofiber layer 3 are hydrospun laminated.

[0025] A preparation method of a slow-release antibacterial facial mask cloth based on onion extract, comprising the following steps: S1, preparing the bottom non-woven fabric: mixing and opening the fiber main material, then carding it into a web, and then hot-rolling it into the bottom non-woven fabric; S2, preparing the onion extract-embedded fiber layer: S2-1: mixing the powdery onion extract with an emulsifier, and preparing an onion extract nano-emulsion through high-pressure homogenization; S2-2: using the melt-blown process to spray polypropylene as a polymer melt on the surface of the bottom non-woven fabric, and at the same time spraying the onion extract nano-emulsion onto the same surface of the bottom non-woven fabric through a side injection system, so that the onion nano-emulsion is embedded in the polypropylene fiber to obtain an onion extract-embedded fiber layer with a fiber diameter of 2-5 μm; S3, polylactic acid nanofiber layer: S3-1: dissolving polylactic acid particles in a solvent to obtain a polylactic acid solution with a concentration of 12-18% (w / v); S3-2: preparing a polylactic acid nanofiber layer with a fiber diameter of 300-1200 nm on the surface of the onion extract-embedded fiber layer through the electrospinning process; S4, hot-rolling, hydroentangling and compounding the above three fiber layers, and drying to obtain the facial mask cloth.

[0026] Example 1: A preparation method of a slow-release antibacterial facial mask cloth based on onion extract, comprising the following steps: S1, preparing the bottom non-woven fabric: The fiber main material is prepared according to the following weight parts: 25 parts of viscose fiber, 4 parts of mint fiber, 2 parts of blueberry fiber, and 5 parts of high-shrinkage polyester fiber. Mixing and opening the fiber main material, then carding it into a web, and then hot-rolling it into the bottom non-woven fabric; S2, preparing the onion extract-embedded fiber layer: S2-1: mixing the powdery onion extract with an emulsifier, and preparing an onion extract nano-emulsion through high-pressure homogenization; S2-2: using the melt-blown process to spray polypropylene as a polymer melt on the surface of the bottom non-woven fabric, and at the same time spraying the onion extract nano-emulsion onto the same surface of the bottom non-woven fabric through a side injection system, so that the onion nano-emulsion is embedded in the polypropylene fiber to obtain an onion extract-embedded fiber layer with a fiber diameter of 5 μm; S3, polylactic acid nanofiber layer: S3-1: dissolving polylactic acid particles in a solvent to obtain a polylactic acid solution with a concentration of 18% (w / v); S3-2: preparing a polylactic acid nanofiber layer with a fiber diameter of 1200 nm on the surface of the onion extract-embedded fiber layer through the electrospinning process; S4, hot-rolling, hydroentangling and compounding the above three fiber layers, and drying to obtain the facial mask cloth.

[0027] In step s2-1, the preparation method of the onion extract is as follows: After crushing the onion, it is immersed in a citric acid buffer solution with a pH of 5.5, 0.3% (w / v) of L-cysteine lyase is added, and it is treated in a microwave at 45°C and 350 W for 20 min; The primary filtrate is obtained by preliminary filtration with a filter screen, the primary filtrate is filtered through a ceramic membrane gradient to obtain a secondary filtrate, and the secondary filtrate is dehydrated to obtain a powdery onion extract. The emulsifier in step s2-1 is Tween-80 emulsifier, which is directly purchased.

[0028] In step s2-2, the melt flow index of the polymer melt is formulated to be 95 g / 10 min, the extrusion amount of the polymer melt is 0.6 g / hole / min, the temperature of the meltblown die head is 192°C, the air jet angle in the meltblown die head is 48°, and the air pressure in the meltblown die head is 0.25 Mpa; The injection temperature of the lateral injection system is 192°C, and the injection angle is 40°; The percentage weight of the onion extract in the onion extract-embedded fiber layer prepared is 12%.

[0029] In step s3-1, first add polylactic acid particles to DCM solvent until completely dissolved; Then slowly add DMF solvent to the solution at a speed of 1.5 mL / min to obtain a polylactic acid solution with a viscosity of 1500 cP.

[0030] Example 2: A preparation method of a sustained-release antibacterial facial mask cloth based on onion extract, comprising the following steps: s1. Prepare the bottom non-woven fabric: The fiber main materials are prepared according to the following weight parts: 15 parts of viscose fiber, 2 parts of mint fiber, 1 part of blueberry fiber, and 3 parts of high shrinkage polyester fiber. The fiber main materials are mixed, opened and then carded into a web, and then hot-rolled to form the bottom non-woven fabric; s2. Prepare the onion extract-embedded fiber layer: s2-1: Mix the powdery onion extract with an emulsifier, and prepare an onion extract nanoemulsion by high-pressure homogenization; s2-2: Use the meltblown process to spray polypropylene as the polymer melt on the surface of the bottom non-woven fabric, and at the same time spray the onion extract nanoemulsion onto the same surface of the bottom non-woven fabric through a lateral injection system, so that the onion nanoemulsion is embedded in the polypropylene fiber to obtain an onion extract-embedded fiber layer with a fiber diameter of 2 μm; s3. Polylactic acid nanofiber layer: s3-1: Dissolve polylactic acid particles in a solvent to obtain a polylactic acid solution with a concentration of 12% (w / v); s3-2: Use the electrospinning process to prepare a polylactic acid nanofiber layer with a fiber diameter of 300 nm on the surface of the onion extract-embedded fiber layer; s4. Hot-roll and hydroentangle the above three fiber layers, and dry them to obtain the facial mask cloth.

[0031] In step s2-1, the preparation method of the onion extract is as follows: After crushing the onion, it is immersed in a citric acid buffer solution with a pH of 5, 0.1% (w / v) of L-cysteine lyase is added, and it is treated in a microwave with a power of 300 W at 40 °C for 10 min; The primary filtrate is obtained by preliminary filtration with a filter screen, the primary filtrate is filtered through a ceramic membrane gradient to obtain a secondary filtrate, and the secondary filtrate is dehydrated to obtain a powdery onion extract. The emulsifier in step s2-1 is Tween-80 emulsifier, which is directly purchased.

[0032] In step s2-2, the melt flow index of the polymer melt is set to 80 g / 10 min, the extrusion amount of the polymer melt is 0.3 g / hole / min, the temperature of the meltblown die head is 185 °C, the gas injection angle in the meltblown die head is 40°, and the gas pressure in the meltblown die head is 0.12 Mpa; The injection temperature of the lateral injection system is 185 °C, and the injection angle is 35°; The percentage weight of the onion extract in the onion extract-embedded fiber layer prepared is 8%.

[0033] In step s3-1, first add polylactic acid particles to DCM solvent until completely dissolved; Then slowly add DMF solvent to the solution at a rate of 1 mL / min to obtain a polylactic acid solution with a viscosity of 1200 cP.

[0034] Example 3: A preparation method of a slow-release antibacterial facial mask cloth based on onion extract, comprising the following steps: s1. Prepare the bottom non-woven fabric: The fiber main materials are prepared according to the following weight parts: 20 parts of viscose fiber, 3 parts of mint fiber, 2 parts of blueberry fiber, and 4 parts of high shrinkage polyester fiber. The fiber main materials are mixed, opened and then carded into a web, and then hot-rolled to prepare the bottom non-woven fabric; s2. Prepare the onion extract-embedded fiber layer: s2-1: Mix the powdery onion extract with an emulsifier, and prepare an onion extract nanoemulsion by high-pressure homogenization; s2-2: Use the meltblown process to spray polypropylene as the polymer melt on the surface of the bottom non-woven fabric, and at the same time spray the onion extract nanoemulsion onto the same surface of the bottom non-woven fabric through a lateral injection system, so that the onion nanoemulsion is embedded in the polypropylene fiber to obtain an onion extract-embedded fiber layer with a fiber diameter of 4 μm; s3. Polylactic acid nanofiber layer: s3-1: Dissolve polylactic acid particles in a solvent to obtain a polylactic acid solution with a concentration of 15% (w / v); s3-2: Use the electrospinning process to prepare a polylactic acid nanofiber layer with a fiber diameter of 750 nm on the surface of the onion extract-embedded fiber layer; s4. Hot-roll and hydroentangle the above three fiber layers, and dry them to obtain the facial mask cloth.

[0035] In step s2-1, the preparation method of the onion extract is as follows: After crushing the onion, it is immersed in a citric acid buffer solution with a pH of 5.2, 0.2% (w / v) of L-cysteine lyase is added, and it is treated in a microwave with a power of 300-350 W at 42 °C for 15 min; The primary filtrate is obtained by preliminary filtration with a filter screen, the secondary filtrate is obtained by gradient filtration of the primary filtrate through a ceramic membrane, and the secondary filtrate is dehydrated to obtain a powdery onion extract. The emulsifier in step s2-1 is Tween-80 emulsifier, which is obtained by direct purchase.

[0036] In step s2-2, the melt flow index of the polymer melt is formulated to be 90 g / 10 min, the extrusion amount of the polymer melt is 0.5 g / hole / min, the temperature of the meltblown die head is 190 °C, the air jet angle in the meltblown die head is 45°, and the air pressure in the meltblown die head is 0.2 Mpa; The injection temperature of the lateral injection system is 190 °C, and the injection angle is 36°; The percentage weight of the onion extract in the onion extract-embedded fiber layer prepared is 10%.

[0037] In step s3-1, first add polylactic acid particles to the DCM solvent until completely dissolved; Then, slowly add the DMF solvent to the solution at a speed of 1.2 mL / min to obtain a polylactic acid solution with a viscosity of 1400 cP.

[0038] Example 4: 1-2% of powdery onion extract by mass is added to the polylactic acid solution prepared in step s3-1, and a polylactic acid composite solution is obtained by ultrasonic dispersion. The remaining processes are the same as those in Example 3.

[0039] Example 5: In step s3-2, a double-layer coaxial electrospinning process is adopted, with the inner layer using a polylactic acid solution and the outer layer using a polyvinyl alcohol solution; The polyvinyl alcohol solution is prepared by dissolving polyvinyl alcohol in deionized water, and the concentration of the polyvinyl alcohol solution is 10-12% (w / v); When the polylactic acid nanofiber layer prepared in step s3-2 is subjected to hydroentangling composite in step s4, the polyvinyl alcohol in the polylactic acid nanofiber layer is removed by washing with water, so that a honeycomb-like pore structure is formed in the polylactic acid nanofiber layer. The remaining processes are the same as those in Example 3.

[0040] The liquid loading rate of the mask cloth prepared through the above examples reaches 320%, the slow-release time of the onion extract reaches 2-6 h, and after storing for 3 months under the conditions of 40 °C / 75% RH, the retention rate of quercetin in the onion extract in the mask cloth is >90%, thus maintaining stable antibacterial and antioxidant properties.

[0041] In the description of the present invention, it should be understood that the directions or positional relationships indicated by up and down, left and right, inner end, outer end, one end, the other end, etc. are based on the orientation or positional relationship shown in the drawings, and are only for the purpose of more clearly facilitating the description of the technical solution of the present invention, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific orientation, and should not be construed as a limitation on the present invention.

[0042] Although specific embodiments of the present invention are described in detail herein, they are given for illustrative purposes only and should not be considered as limiting the scope of the present invention. Various substitutions, changes, and modifications can be conceived without departing from the spirit and scope of the present invention.

Claims

1. A slow-release antibacterial facial mask cloth based on onion extract, characterized in that The invention comprises a bottom non-woven fabric, an onion extract embedded fiber layer and a polylactic acid nanofiber layer in sequence, wherein the bottom non-woven fabric, the onion extract embedded fiber layer and the polylactic acid nanofiber layer are compounded by hydroentanglement.

2. A preparation method of a sustained-release antibacterial facial mask cloth based on onion extract, characterized in that, The following steps are involved: s1. Preparing the bottom non-woven fabric: mixing and opening the main fiber materials and then combing them into a web, and then hot-rolling them into the bottom non-woven fabric; s2. Preparation of onion extract embedded fiber layer: s2-1: mixing powdered onion extract with an emulsifier and preparing an onion extract nanoemulsion by high pressure homogenization; s2-2: The melt-blowing process is used to spray polypropylene as a polymer melt onto the surface of the bottom non-woven fabric, and at the same time, the onion extract nanoemulsion is sprayed onto the same surface of the bottom non-woven fabric through a lateral injection system, so that the onion nanoemulsion is embedded in the polypropylene fiber to obtain an onion extract embedded fiber layer with a fiber diameter of 2-5 μm; s3, polylactic acid nanofiber layer: s3-1: dissolving polylactic acid particles in a solvent to prepare a polylactic acid solution with a concentration of 12-18% (w / v); s3-2: The polylactic acid solution is electrospinned on the surface of the onion extract embedded fiber layer to prepare a polylactic acid nanofiber layer with a fiber diameter of 300-1200 nm; s4. The three fiber layers are hot-rolled, hydroentangled and compounded, and dried to obtain a facial mask cloth.

3. The preparation method of a sustained-release antibacterial facial mask cloth based on onion extract according to claim 2, characterized in that, The main fiber materials in step s1 are prepared according to the following weight parts: 15-25 parts of viscose fiber, 2-4 parts of mint fiber, 1-2 parts of blueberry fiber, and 3-5 parts of high shrinkage polyester fiber.

4. The preparation method of a sustained-release antibacterial facial mask cloth based on onion extract according to claim 2, characterized in that, In step s2-1, the onion extract is prepared as follows: Crush the onion and immerse it in a citric acid buffer with a pH of 5-5.5, add 0.1-0.3% (w / v) L-cysteine lyase, and treat it in a microwave at 40-45°C and 300-350W for 10-20min; A primary filtrate is obtained by preliminary filtration through a filter screen, the primary filtrate is gradient filtered through a ceramic membrane to obtain a secondary filtrate, and the secondary filtrate is dehydrated to obtain a powdered onion extract.

5. The preparation method of a sustained-release antibacterial facial mask fabric based on onion extract according to claim 2, characterized in that, In step s2-2, the melt flow index of the polymer melt is 80-95 g / 10 min, the extrusion amount of the polymer melt is 0.3-0.6 g / hole / min, the temperature of the meltblowing die is 185-192° C., the air flow injection angle in the meltblowing die is 40-48°, and the air flow pressure in the meltblowing die is 0.12-0.25 MPa; The injection temperature of the lateral injection system is 185-192°C, and the injection angle is 35-40°; the weight percentage of the onion extract in the prepared onion extract embedded fiber layer is 8-12%.

6. The preparation method of a sustained-release antibacterial facial mask cloth based on onion extract according to claim 2, characterized in that, In step s3-1, the polylactic acid particles are first added to the DCM solvent until they are completely dissolved; then the DMF solvent is slowly added to the solution at a rate of 1-1.5 mL / min to obtain a polylactic acid solution with a viscosity of 1200-1500 cP.

7. The preparation method of a sustained-release antibacterial facial mask cloth based on onion extract according to claim 6, characterized in that, A powdered onion extract having a mass ratio of 1-2% is added to the polylactic acid solution prepared in step s3-1, and a polylactic acid composite solution is prepared by ultrasonic dispersion.

8. The preparation method of a sustained-release antibacterial facial mask fabric based on onion extract according to claim 2 or 6 or 7, characterized in that, In step S3-2, a double-layer coaxial electrospinning process is adopted. The inner layer uses a polylactic acid solution, and the outer layer uses a polyvinyl alcohol solution; Among them, the polyvinyl alcohol solution is prepared by dissolving polyvinyl alcohol in deionized water, and the concentration of the polyvinyl alcohol solution is 10-12% (w / v); In step S3-2, a polylactic acid nanofiber layer is prepared. When subjected to hydroentangling composite in step S4, the polyvinyl alcohol in the polylactic acid nanofiber layer is removed by washing with water, so that a honeycomb-like pore structure is formed in the polylactic acid nanofiber layer.

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