Concealer type nanofiber mask as well as preparation method and application thereof

Abstract

The invention provides a concealer type nanofiber mask and a preparation method and application thereof, and the preparation method comprises the following steps: 1) preparing a spinning base solution: dissolving polyvinylpyrrolidone (PVP) in a solvent to prepare 5wt.%-15wt.% of the spinning base solution; 2) preparing a spinning solution: adding a cosmetic-grade coloring agent into the spinning base solution according to the skin color to obtain the spinning solution, wherein the color of the spinning solution is matched with the skin color; and (3) preparing the concealer type nanofiber mask: spinning the spinning solution by adopting an electrostatic spinning technology to prepare nanofibers as the concealer type nanofiber mask, aiming at solving the defects of the existing mask in the aspects of concealer effect, personalized preparation and multifunctionality, especially meeting the requirements of consumers with different skin colors, and improving the concealer type nanofiber mask. And an efficient concealing effect and a skin care function are provided.

Description

Technical Field

[0001] This invention relates to the field of skin care and cosmetics technology, and in particular to a concealing nanofiber mask, its preparation method and application. The biomimetic skin is prepared using electrospinning technology and can be used for skin blemish coverage, sun protection and personalized beauty applications. Background Technology

[0002] Acne, post-cosmetic surgery facial recovery, pigmentation, vascular birthmarks, moles, and scars are common cosmetic concerns that not only affect appearance but can also have negative psychological impacts. To address these issues, more and more consumers are seeking concealing products such as concealers, eyeshadow sticks, and foundations. However, existing makeup products typically focus solely on coverage and fail to meet the need for simultaneous skincare benefits. Long-term use of these products may clog pores and potentially cause new skin problems due to the irritating ingredients, leaving consumers in a dilemma where "concealing" and "skincare" are difficult to achieve simultaneously.

[0003] As a form of skincare product, face masks do offer certain benefits to the skin, such as hydration, moisturizing, and repair. However, traditional non-woven fabric masks are often predominantly white, which makes them inadequate for meeting consumers' needs for concealing imperfections. After using a face mask, consumers often need to apply concealer before going out, which is cumbersome and prevents the simultaneous application of skincare and concealing. Therefore, developing a face mask that effectively conceals imperfections while deeply nourishing the skin has become crucial for meeting the personalized needs of modern consumers and represents a highly promising development direction for the beauty and skincare industry. Summary of the Invention

[0004] The purpose of this invention is to provide a concealing nanofiber mask, its preparation method, and its application, aiming to solve the shortcomings of existing masks in terms of concealing effect, personalized preparation, and multifunctionality, especially to provide efficient concealing effect and skin care function while meeting the needs of consumers with different skin tones.

[0005] To achieve the above objectives, this technical solution provides a method for preparing a concealing nanofiber facial mask, comprising: 1) Preparation of spinning base solution: Polyvinylpyrrolidone (PVP) is dissolved in a solvent to prepare a spinning base solution of 5 wt.%~15 wt.%; 2) Preparation of spinning solution: Cosmetic-grade colorant is added to the spinning base solution according to the skin color to obtain the spinning solution, wherein the color of the spinning solution matches the skin color; 3) Preparation of concealing nanofiber masks: Nanofibers are prepared by spinning the spinning solution using electrospinning technology to obtain concealing nanofiber masks.

[0006] It's important to note that traditional concealer products mostly use cosmetic-grade colorants, such as titanium dioxide and iron oxide, to cover skin imperfections by adjusting color. However, these colorants can feel heavy on the skin during use, and their skincare benefits are almost negligible. This solution abandons the traditional approach of adding colorants to ordinary masks to achieve a concealing effect. Instead, it innovatively uses electrospinning technology with PVP as the matrix and cosmetic-grade colorants to create a nanofiber mask that matches the color of simulated skin. This concealing nanofiber mask not only effectively covers skin imperfections such as acne marks, blemishes, and scars, but also has sun protection (UPF ≥ 90) and excellent breathability, ensuring skin comfort and health while providing skincare benefits.

[0007] In addition, it is particularly important to emphasize that the preparation method of the concealing nanofiber mask in this solution can avoid the traditional mask mold method. Instead, it uses a convenient electrospinning device to spray the spinning solution onto the surface of the skin, realizing an instant preparation and immediate use method, providing a flexible and immediate concealing effect.

[0008] In other words, in some embodiments, a portable electrospinning device is used to directly spray the spinning solution onto the facial skin to spin nanofibers, thereby preparing a concealing nanofiber mask tailored to individual facial contours and skin tone on-site. That is, this solution utilizes on-site preparation of concealing nanofiber masks, which greatly enhances the personalization and portability of the mask, avoiding the limitations of traditional pre-made masks (such as size and color restrictions), and eliminating the need for additional preservatives to extend the mask's lifespan.

[0009] In some embodiments, polyvinylpyrrolidone (PVP) is dissolved in anhydrous ethanol to prepare a spinning base solution of 5 wt.% to 15 wt.%. Controlling the mass ratio of PVP in this solution is beneficial for achieving good spinnability in subsequent processes. As a water-soluble polymer, polyvinylpyrrolidone (PVP) possesses good biocompatibility, spinnability, and adhesion, and is widely used in electrospinning processes.

[0010] In some embodiments, a cosmetic-grade colorant is added to the spinning base solution according to the skin color to obtain the spinning solution, and the color difference between the spinning solution and the skin color is controlled to be ≤10 and the brightness value is ≤10.

[0011] It should be noted that if the concealer-type nanofiber mask is made on-site, the cosmetic-grade colorant can be adjusted according to the actual skin color to achieve the spinning solution, thus realizing personalized concealing for people with different skin tones.

[0012] In some embodiments, the cosmetic-grade colorant is one or a combination of iron oxide red (RIO), curcumin (Cur), and graphene oxide (GO).

[0013] Regarding the cosmetic-grade colorants selected in this scheme: Iron oxide red (RIO) is an iron oxide pigment with excellent dispersibility, lightfastness, and weather resistance. It can adapt to different environmental conditions, ensuring that the color of the mask is long-lasting and does not easily fade. In addition, iron oxide red (RIO) has the property of absorbing ultraviolet rays, which can help enhance the sun protection function of the mask, allowing users to protect themselves from some ultraviolet damage while concealing blemishes.

[0014] Curcumin (Cur) is a polyphenolic substance extracted from the roots and stems of plants in the ginger family, araceae family, etc. It is stable under acidic conditions, has strong coloring power, bright color, and strong thermal stability. Crucially, it is also safe and non-toxic. Adding it to face masks can provide extra care for the skin on top of concealing blemishes and improving skin inflammation and other problems.

[0015] Graphene oxide (GO) is a novel carbon nanomaterial with a unique two-dimensional structure and excellent properties. It exhibits good light absorption and scattering characteristics, which positively impact the concealing power of face masks. Furthermore, graphene oxide possesses a degree of biocompatibility, reducing the probability of adverse reactions such as allergies when in contact with skin. It also possesses antibacterial properties, helping to maintain the hygiene of face masks, preventing microbial growth, and extending the mask's shelf life. Additionally, GO enhances the fiber's mechanical properties through π-π conjugation and imparts a UPF>90 ultraviolet shielding function.

[0016] It should be emphasized that the introduction of graphene oxide (GO) in this solution not only endows the mask with excellent UV protection performance, but also improves the stability of the fiber structure and the skin-friendly experience of the mask, resulting in a UV protection factor (UPF) of ≥90 for the final concealing nanofiber mask.

[0017] In some embodiments, the mass concentration of PVP is 5.0 wt.% to 20.0 wt.%, the mass ratio of graphene oxide (GO) to PVP is 0.1 wt.% to 1.0 wt.%, the mass ratio of iron oxide red (RIO) to PVP is 1.0 wt.% to 10.0 wt.%, and the mass ratio of curcumin (Cur) to PVP is 0.1 wt.% to 0.8 wt.%.

[0018] It should be noted that in some embodiments, this method determines the ratio of iron oxide red (RIO), curcumin (Cur), and graphene oxide (GO) based on skin color, and then adds curcumin, iron oxide red, and graphene oxide to the spinning base solution in sequence.

[0019] Furthermore, curcumin is added to the spinning base solution and stirred until the curcumin is completely dissolved to obtain a solution. Iron oxide red is added to the solution and stirred evenly to obtain a dispersion solution. Finally, graphene oxide solution is added to the dispersion solution and ultrasonically dispersed to obtain the spinning solution.

[0020] Curcumin, a polyphenol, is soluble in solvents. Adding it first and stirring until completely dissolved provides a uniform foundation for the dispersion of other colorants, preventing undissolved curcumin from affecting the overall dispersion. Iron oxide red, a pigment and solid particles, needs to be stirred evenly in the solution containing dissolved curcumin to ensure thorough dispersion. Adding it first might affect the uniformity of dispersion due to the curcumin's dissolution process. Graphene oxide, a two-dimensional nanomaterial, is prone to agglomeration. Ultrasonic dispersion effectively breaks up these agglomerates. Adding it last and then sonicating prevents re-agglomeration during the initial stirring process, ensuring optimal dispersion. This step-by-step approach fully utilizes the characteristics of each colorant, ensuring uniform composition of the spinning solution. This results in a nanofiber mask with uniform color, stable performance, and excellent concealing and skincare effects.

[0021] That is, this scheme uses polyvinylpyrrolidone (PVP) as the matrix and adopts a ternary composite coloring system of iron oxide red, curcumin and graphene oxide. By precisely controlling the mass ratio of the ternary composite coloring system and combining it with a multi-stage dispersion process in an acetic acid solvent system, the compatibility problem of inorganic / organic / nanomaterials in spinning solution is solved, and fiber coloring uniformity is achieved.

[0022] In some embodiments, the electrospinning technology is controlled under the following conditions: flow rate of 1.0~2.0 mL / h, spinning distance of 10~20 cm, and voltage range of 10~15 kV.

[0023] In some embodiments, the nanofiber diameter is 100~400nm to ensure that the concealing nanofiber mask has good flexibility and breathability.

[0024] Secondly, this solution provides a concealing nanofiber mask, which is a nanofiber prepared by electrospinning technology, wherein the nanofiber is based on PVP and contains colorants of different cosmetic grades.

[0025] In some embodiments, the concealing nanofiber mask is prepared directly on the facial skin on-site using a portable electrospinning device to meet the personalized needs of different skin tones and facial contours, avoiding the problem of traditional masks requiring pre-made molds. Furthermore, this on-the-spot preparation method ensures that no preservatives are added to the concealing nanofiber mask, meeting the modern consumer demand for natural, safe, and environmentally friendly skincare products.

[0026] In some embodiments, the cosmetic-grade colorant is one or a combination of iron oxide red (RIO), curcumin (Cur), and graphene oxide (GO), and the cosmetic-grade colorant is mixed to ensure that the color difference and brightness difference between the concealing nanofiber mask and the facial skin meet the requirements of ≤10 and ±1, which can effectively cover skin blemishes such as acne marks, spots, and scars.

[0027] In some embodiments, the concealing nanofiber mask has good flexibility and fit, with a tensile strength of 1.0 MPa and a tensile strain of up to 120%, enabling it to better fit the facial contours and improve the comfort of use.

[0028] In some embodiments, the concealing nanofiber mask has concealing, sun protection and breathable functions, and the ultraviolet protection performance of the concealing nanofiber mask is UPF≥90.

[0029] In summary, the concealing nanofiber mask provided by this solution has functions such as concealing, sun protection, and personalized skin care. It can effectively cover skin imperfections and has functions such as anti-ultraviolet rays, sun protection, skin-friendly and breathable. It is especially suitable for covering skin problems such as acne marks, spots, and scars, and is widely used in the cosmetics industry and personalized beauty and skin care scenarios.

[0030] Compared with existing technologies, this technical solution has the following characteristics and beneficial effects: This solution employs a ternary composite coloring system of iron oxide red, curcumin, and graphene oxide. By precisely controlling the mass ratio of these three components with PVP, and combining it with a multi-stage dispersion process, it overcomes the limitations of traditional single-colorant methods. The multi-stage dispersion process ensures the compatibility of inorganic, organic, and nanomaterials in the spinning solution, achieving uniform coloring of the nanofibers. This concealing nanofiber mask can precisely match simulated skin, solving the problem of unsatisfactory concealing effects in existing technologies.

[0031] This innovative solution utilizes portable or handheld electrospinning equipment, allowing for direct spraying onto the skin to create personalized masks on-site, eliminating the limitations of traditional pre-made molds. This method adapts to different facial contours and skin tones, greatly enhancing the flexibility and convenience of preparation and meeting individual needs. Because of its on-demand preparation mode, no preservatives are required, avoiding potential skin allergies or irritation caused by preservatives, thus aligning with modern consumers' demand for natural, safe, and environmentally friendly skincare products.

[0032] In addition to its high-efficiency concealing properties, the concealing nanofibers in this solution also have excellent sun protection (UV protection factor UPF≥90), thanks to the UV shielding effect of graphene oxide. They also have good breathability, and graphene oxide enhances the mechanical properties of the fibers through π-π conjugation, expanding the application range of traditional masks in areas such as skin blemish coverage, sun protection, and personalized skincare. Attached Figure Description

[0033] Figure 1 The following are SEM images and fiber diameter distributions of commercial nonwoven fabric masks and nanofiber masks in Example 1: (a) Commercial nonwoven fabric mask; (b) Blank nanofiber mask; (c) 6.0% GO nanofiber mask; (ef) correspond to the fiber diameter distributions of (a), (b), and (c), respectively.

[0034] Figure 2 This is the stress-strain curve of the concealer-type face mask in Example 2.

[0035] Figure 3 This is a comparison chart of the hydrophilic properties of nanofiber masks and commercial nonwoven fabrics.

[0036] Figure 4 Macroscopic images of concealing nanofiber masks with different spinning times: (a) The receiving carrier is tin foil; (b) The receiving carrier is simulated skin; (c) The nanofiber mask peeling condition.

[0037] Figure 5 shows the concealing performance of nanofiber masks: (a) Schematic diagram of nanofiber mask concealing effect; (b) Color values ​​of simulated skin and blank nanofiber masks with different spinning times; (c) Color values ​​of nanofiber masks with different concentrations of GO.

[0038] Figure 6 The following is a schematic diagram of the moisture permeability test of nanofiber masks (a) and a comparison of the moisture permeability of commercial nonwoven fabrics and nanofiber masks (b).

[0039] Figure 7 The UV protection properties of the nanofiber mask are as follows: (a) Schematic diagram of UV protection; (b) UV transmittance; (c) UV protection factor. Detailed Implementation

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0041] Example 1: Preparation of a face film 1) Preparation of spinning solution: A 20 wt.% gelatin spinning solution was prepared using 80% acetic acid. The solution was stirred on a constant-temperature stirrer for 4.0 h to obtain a clear and transparent spinning solution. Curcumin (Cur) at a mass ratio of 0.4% to PVP was then added, and stirring continued until the gelatin was completely mixed in the spinning solution. Stirring continued until Cur was completely dissolved. RIO at a mass ratio of 10% to PVP was then added, and the solution was stirred to form a homogeneous dispersion. A 1.0 mg / mL GO solution was prepared and dispersed using an ultrasonic cleaner for 30 min. GO was added at mass ratios of 0.1%, 0.2%, 0.3%, 0.4%, and 0.5% (mGO:mPVP) to prepare the spinning solution. The solution was stirred until homogeneous and ready for use.

[0042] 2) Preparation of the face mask: Spinning solutions with different glycerin contents were drawn up, and a 21G needle was fixed to the push pump. Aluminum foil was attached to the fibers on the roller receiver, and then the electrospinning apparatus was started. The spinning parameters were set as follows: speed 1.5 mL / h, spinning distance 15 cm, positive voltage 12.0 ± 1.0 KV, negative voltage 2.5 ± 0.5 KV, and spinning time 6.0 h.

[0043] 3) Preservation of the mask: Place the mask prepared in step 2) into a vacuum drying oven and dry for 4.0 h, then store it in a sealed bag with desiccant.

[0044] Example 2: Performance Characterization of Facial Mask (1) Test 1: Morphological observation Cut 0.5 cm x 0.5 cm pieces of dried nanofiber mask and commercial nonwoven fabric, respectively. Fix the samples onto the sample stage with conductive adhesive, ensuring the samples are flat, otherwise it will affect the observation. After sputtering with gold for 1.0 min, place them in the sample chamber and observe them using a Phenom XL scanning electron microscope. Figure 1 The prepared nanofiber masks were observed using SEM, with commercial nonwoven fabric masks used as a control. The fiber diameter was measured using ImageJ software. The results are shown below. Figure 1 .

[0045] like Figure 1 As shown in (b), the blank nanofiber mask contains many white dots, which are not beads or droplets, and may be caused by the insolubility of iron oxide red in the spinning solution. Figure 1As shown in (c), the nanofiber mask containing 6.0% GO exhibits a uniform fiber distribution with no obvious white specks. In contrast, the fiber diameter of commercial nonwoven fabrics is mainly around 10 μm, while the nanofiber mask's fiber diameter reaches the nanometer level. Those skilled in the art will know that finer fibers have a softer feel and can be made into highly dense materials. The interlacing of fibers forms numerous pores, which facilitates water vapor permeation and the loading of other components, making it a promising candidate for use as a mask substrate.

[0046] (2) Test 2: Mechanical properties The prepared nanofiber masks were dried at room temperature for 4.0 h and 8.0 h, respectively. Samples of 4.0 cm x 1.0 cm were cut from each sample, and a commercially available nonwoven fabric mask of the same size was cut as a control. The two ends of the samples were fixed with clamps, and the samples were tested using a Shanghai Hengyu HY-940FS computer-controlled tensile and compressive testing machine. The test conditions were: tensile speed 50 mm / min, maximum bearing force 10 N. The masks will undergo stretching and peeling processes during use, therefore, they need to possess certain mechanical properties. The nanofiber masks dried naturally for 4.0 h and 8.0 h were tested using a tensile testing machine, and compared with commercially available nonwoven fabric masks. The results are shown in the figure. Figure 2 .

[0047] As shown in the figure, the yield stress of commercial nonwoven fabric can reach 6.0 MPa, significantly higher than that of nanofiber masks (<1.0 MPa). Therefore, the nanofiber mask prepared in this method is softer and more skin-friendly. Furthermore, due to the larger fiber diameter and pore size, the nonwoven fabric has multiple fracture points, making it less prone to complete breakage. The stress at complete breakage of the nonwoven fabric, i.e., its tensile strength, is higher than that of the nanofiber mask. Extending the drying time of the nanofiber mask increases the strain from 70% to 120%, improving its tensile strength and toughness. In conclusion, the nanofiber mask prepared using this method is softer and more resilient than nonwoven fabric.

[0048] (3) Test 3: Hydrophilicity Nanofiber masks and nonwoven fabrics were cut into 1.0 cm × 1.0 cm samples and attached to double-sided tape fixed to a glass slide using tweezers. A KRUSS DSA 30 contact angle meter (Germany) was used in automatic droplet mode. The hydrophilicity was analyzed by measuring the contact angle between the water droplet and the sample surface. The results are as follows: Figure 3 As shown.

[0049] As shown in the figure, the commercial nonwoven fabric mask can be completely wetted by water droplets, with a contact angle of 0°. This is due to its visible pores, allowing water droplets to pass through completely. The contact angle of the control group is 16.4°, indicating its high affinity for water. This is because the main component of the nanofiber mask, PVP, contains hydrophilic groups. The addition of GO increases the contact angle between water and the surface of the nanofiber mask, but it still exhibits hydrophilicity, indicating that the mask has good skin-friendly properties.

[0050] Example 3: Use and Functional Testing of the Facial Mask (1) Test 1: Concealing performance Simulated skin and nanofiber mask samples were placed in the light-transmitting holes, respectively. The Lab values ​​of the sample colors were measured using a DATACOLOR 650 colorimeter from Shanghai Hecheng Industrial Co., Ltd. The color differences between the nanofiber mask and the simulated skin were compared to evaluate their concealing performance. An electrospinning apparatus was used, with tin foil and simulated skin as the receiving carriers, respectively. Markers were applied to the receiving carriers to simulate skin blemishes. Nanofiber masks were prepared using spinning time as a variable, and their ability to cover blemishes was observed. The spinning results are shown in Figure 4(a).

[0051] In addition, from Figure 4 As shown in (b), when using tin foil as a carrier, a spinning time of 2.0 minutes is sufficient to completely cover the mark and achieve a concealing effect. However, simulated skin requires at least 8.0 minutes to achieve a similar effect. This is likely because simulated skin is non-conductive, resulting in many fibers not being absorbed during the spinning process. Since the mask needs to be removed after use, its peelability needs to be investigated.

[0052] In this experiment, tweezers were used to peel off the nanofiber mask from the surface of simulated skin to simulate the peeling process after mask use. The peelability of the nanofiber mask was observed, and the results are as follows: Figure 4 As shown in (c) of the figure, the nanofiber mask can be completely peeled off without damage, and there is no residue on the simulated skin surface. Therefore, in actual use, the mask can be easily and completely removed from the face, which is relatively convenient and not complicated. Figure 5 This is a schematic diagram of a nanofiber mask for concealing blemishes. After using a nanofiber mask that matches your skin tone, acne or blemishes on the face can be covered, thus achieving a concealing effect. To quantitatively evaluate its concealing ability, the Lab values ​​of the simulated skin and the nanofiber mask colors were compared using a colorimeter. The results are as follows... Figure 5 As shown.

[0053] from Figure 5As can be seen from (b), the nanofiber mask with added RIO and Cur has a value (a) representing red and a value (b) representing yellow that are similar to those of simulated skin. When the spinning time reaches 8.0 min, the brightness (L) of the nanofiber mask is 78.14, which is the smallest difference from the simulated skin (65.33), consistent with the results of the macroscopic photograph.

[0054] To reduce the shine of the nanofiber mask, a brownish-yellow GO colorant was selected for adjustment. From Figure 5 As shown in (c), the brightness difference ΔL between the 2.0% GO and 4.0% GO samples and the simulated skin decreased significantly, indicating that GO can reduce the brightness of the nanofiber mask. When the GO content was greater than 6.0%, ΔL was negative, indicating that the sample color was too dark. The ΔL of the 6.0% GO sample was almost 0, and the difference in brightness between it and the simulated skin was negligible. At this point, the color difference value ΔE was 9.3, the smallest color difference from the simulated skin, and the best concealing effect. This allows people who want to cover facial blemishes to adjust the color according to different skin tones, meeting the needs of personalized concealing masks.

[0055] (2) Test 2: Moisture permeability The moisture permeability test was conducted using the moisture permeation cup method. First, an appropriate amount of anhydrous calcium chloride was weighed into the moisture permeation cup, ensuring its surface was 3.0-4.0 mm below the bottom surface of the sample. A nanofiber mask sample of appropriate size was cut and placed on the moisture permeation cup along with a non-woven fabric. The sample was then fixed in place. The YG(B)216X fabric moisture permeability meter was started, and the experimental conditions were set to: temperature 37℃, humidity 65%. The instrument began adjusting the temperature and humidity. After adjustment, the assembled moisture permeation cup was placed on the sample holder (without the lid), ensuring the holder was balanced to prevent the cup from falling. After 30 minutes, the balanced moisture permeation cup was removed, the lid was replaced, and the cup was placed in a desiccator for 30 minutes. Removing the lid aimed to address the shortcomings of existing masks in terms of concealing effect, personalized preparation, and multifunctionality, especially in providing efficient concealing effect and skincare function while meeting the needs of consumers with different skin tones. The mass of the moisture permeation cup was weighed. After weighing, the lid was removed, and the cup was placed in the fabric moisture permeability meter for 1.0 h, then removed and weighed again. Calculate the moisture permeability of each sample using the following formula:

[0056] In the formula, WAT represents the moisture permeability per square meter per day (g / m²). 2 .h); Δm - the difference in mass between two permeation cups in the same experiment; S - the effective experimental area of ​​the sample; t - the experimental time. Face masks are typically used for about 20 minutes, during which time the skin is isolated from the air, forming a closed layer that hinders the flow of water vapor between the skin and the air. Therefore, the mask substrate needs to have a certain degree of permeability to ensure contact between the skin and water vapor in the air.

[0057] Figure 6 (a) is a schematic diagram of the moisture permeability test. The moisture permeability of the sample is determined based on the ability of CaCl2 to absorb water vapor. From Figure 6 As can be seen from (b), the moisture permeability of the nanofibers is 160 g / m³. 2 The moisture permeability was approximately the same as that of commercial nonwoven fabrics, with no significant difference. Nonwoven fabrics have looser fibers and larger pores, allowing water vapor to pass through easily, thus exhibiting good moisture permeability. In contrast, the PVP substrate for nanofiber masks is a hydrophilic polymer with inherently good hygroscopic properties. The nanofibers have small diameters and high porosity, so their moisture permeability is similar to that of commercial nonwoven fabrics. This indicates that the nanofiber mask prepared in this chapter has good moisture permeability, is skin-friendly and breathable, and can be used as a mask substrate.

[0058] (3) Test 3: UV resistance The UV-2000F UV resistance tester was used for testing. The nanofiber mask sample and the commercial nonwoven fabric were fixed in place with sample clips. The distance between the sample and the test head was adjusted to 1.0-2.0 mm, and the wavelength range was set to 250-400 nm. The results are as follows: Figure 7 As shown in (b), within the wavelength range of 250-450 nm, the transmittance of ultraviolet light to commercial nonwoven fabrics can reach 90%, while the transmittance of nanofiber masks decreases with increasing GO content. When the GO content reaches 6.0%, ultraviolet light can hardly penetrate the nanofiber mask. The UV protection factor (UPF) evaluates the ability to resist ultraviolet rays based on both UVA and UVB. When a product has a UPF greater than 50 and an ultraviolet transmittance not higher than 5.0%, it indicates that it has sun protection capabilities. Figure 7(c) shows that the 6.0% GO nanofiber mask has a UV protection factor of about 90, which is significantly different from that of commercial nonwoven fabric masks. When the GO concentration is low, the protection factor of the nanofiber mask is low. Therefore, concealing nanofiber masks have good anti-ultraviolet performance, meeting the standards for sun protection products, and providing them with more flexible usage time and location.

[0059] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for preparing a concealing nanofiber facial mask, characterized in that, include: 1) Preparation of spinning base solution: Polyvinylpyrrolidone (PVP) was dissolved in a solvent to prepare a spinning base solution of 5 wt.%~15 wt.%; 2) Preparation of spinning solution: Cosmetic-grade colorant is added to the spinning base solution according to the skin color to obtain the spinning solution, wherein the color of the spinning solution matches the skin color; 3) Preparation of concealing nanofiber masks: Nanofibers are prepared by spinning the spinning solution using electrospinning technology to obtain concealing nanofiber masks.

2. The method for preparing the concealing nanofiber mask according to claim 1, characterized in that, Nanofibers were prepared by directly spraying spinning solution onto facial skin using a portable electrospinning device.

3. The method for preparing the concealing nanofiber facial mask according to claim 1, characterized in that, Cosmetic-grade colorants are added to the spinning base solution according to the skin color to obtain the spinning solution. The color difference between the spinning solution and the skin color is controlled to be ≤10, and the brightness value is ≤10.

4. The method for preparing the concealing nanofiber mask according to claim 1, characterized in that, Cosmetic-grade colorants are one or a combination of iron oxide red (RIO), curcumin (Cur), and graphene oxide (GO).

5. The method for preparing the concealing nanofiber facial mask according to claim 1, characterized in that, The mass concentration of PVP ranges from 5.0 wt.% to 20.0 wt.%, the mass ratio of graphene oxide (GO) to PVP ranges from 0.1 wt.% to 1.0 wt.%, the mass ratio of iron oxide red (RIO) to PVP ranges from 1.0 wt.% to 10.0 wt.%, and the mass ratio of curcumin (Cur) to PVP ranges from 0.1 wt.% to 0.8 wt.%.

6. The method for preparing the concealing nanofiber facial mask according to claim 1, characterized in that, Curcumin was added to the spinning base solution and stirred until the curcumin was completely dissolved to obtain a solution. Iron oxide red was added to the solution and stirred evenly to obtain a dispersion solution. Finally, graphene oxide solution was added to the dispersion solution and ultrasonically dispersed to obtain the spinning solution.

7. The method for preparing the concealing nanofiber facial mask according to claim 1, characterized in that, Nanofibers have a diameter of 100~400nm.

8. A concealing nanofiber facial mask, characterized in that, The concealing nanofiber mask is prepared by the preparation method according to any one of claims 1 to 7, and is a nanofiber prepared by electrospinning technology, wherein the nanofiber is based on PVP and contains colorants of different cosmetic grades.

9. The concealing nanofiber mask according to claim 8, characterized in that, The color difference and brightness difference between the concealing nanofiber mask and the facial skin meet the requirements of ≤10 and ±1, respectively, and the ultraviolet protection performance of the concealing nanofiber mask is UPF≥90.

10. The concealing nanofiber mask according to claim 8, characterized in that, The tensile strength reaches 1.0 MPa, and the tensile strain reaches 120%.

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