Small molecule collagen peptide core-shell nanofiber skin care fabric and preparation method thereof

Abstract

The application discloses a small-molecule collagen peptide core-shell nanofiber skin care fabric and a preparation method thereof, and relates to the technical field of functional textile material preparation. The fabric is formed by stacking light-crosslinking nanofibers with core-shell structures, wherein the core-shell structure nanofiber takes a light-crosslinking polymer as a core layer and a small-molecule collagen peptide grafted with a photosensitive group as a shell layer; the light-crosslinking polymer is a continuous-phase fiber skeleton matrix, which provides basic mechanical support and has an unsaturated double bond capable of participating in a crosslinking reaction; and the small-molecule collagen peptide grafted with the photosensitive group is a surface functional phase, which endows the fabric with skin care active efficacy and has a light-triggerable reaction site. Through the mutual cooperation of the core-shell structure design, a light-initiated in-situ crosslinking mechanism and a mild preparation process, the application solves the problems of the existing small-molecule collagen peptide electrospun fibers, such as easy loss of activity, poor washing resistance, insufficient mechanical strength and slow efficacy release.

Description

Technical Field

[0001] This invention relates to the field of functional textile material preparation technology, specifically to a small molecule collagen peptide core-shell nanofiber skin care fabric and its preparation method. Background Technology

[0002] Small molecule collagen peptides are small-molecule active substances formed by multiple amino acids linked by peptide bonds. They possess various skin care activities such as moisturizing and skin repair, and have high application value in functional fabrics such as skin care textiles and medical dressings. However, small molecule collagen peptides have poor molecular structure stability and are sensitive to processing conditions such as high temperature and strong shear. Moreover, most small molecule collagen peptides are highly water-soluble, and are easily lost during washing and friction after being loaded into the fiber matrix, making it difficult to maintain their efficacy in the long term.

[0003] Electrospinning is a mature technology for preparing nanofiber materials. Its working principle is as follows: a polymer solution or melt is introduced into a high-voltage electric field. The charged polymer fluid overcomes surface tension under the action of the electric field, forming a fine jet. During its flight, the jet continuously stretches and refines, accompanied by rapid solvent evaporation or melt cooling and solidification, ultimately depositing a fiber-laden film with diameters ranging from tens to hundreds of nanometers onto a receiving substrate. Electrospun nanofibers possess characteristics such as large specific surface area, high porosity, and tunable fiber morphology and structure, providing ample loading sites and contact area for functional components, making them a commonly used carrier for preparing high-value-added functional fabrics.

[0004] Currently, the mainstream method for loading small molecule collagen peptides into electrospun fibers is blend spinning, which involves directly adding the small molecule collagen peptides to the polymer spinning solution, mixing them evenly, and then performing uniaxial electrospinning. This method has several drawbacks: First, the strong shearing action during spinning, and the high-temperature melting conditions required by some polymer systems, can disrupt the spatial structure of the small molecule collagen peptides, leading to their inactivation. Second, the compatibility between the small molecule collagen peptides and the polymer matrix is ​​limited, and local aggregation easily occurs after blending, causing a decrease in fiber mechanical properties and affecting the fabric's performance. Third, the small molecule collagen peptides are uniformly embedded within the fiber and cannot directly contact the skin, requiring slow release through diffusion, resulting in slow onset of efficacy and low utilization of active ingredients. Fourth, the physical embedding method cannot restrict the migration of small molecule collagen peptides; after repeated washing, a large amount of small molecule collagen peptides dissolve, leading to rapid degradation of fabric functionality.

[0005] To improve the release efficiency of small-molecule collagen peptides, some studies have employed coaxial electrospinning technology to incorporate these peptides into the shell spinning solution, thereby enriching them on the fiber surface. While this method accelerates the release of active ingredients, it still falls under the category of physical coating. There are no chemical bonds between the shell-layer small-molecule collagen peptides and the core polymer, making them prone to detachment during washing and friction, thus failing to substantially improve wash fastness. Furthermore, the introduction of the shell layer weakens the overall mechanical properties of the fiber, failing to address the mechanical degradation caused by the addition of functional components.

[0006] In existing technologies, photocrosslinking technology is mostly used for the mechanical reinforcement of pure polymer electrospun fibers or for the grafting modification of small molecule collagen peptides on the surface of planar substrates. There is no solution that combines coaxial core-shell structure design with photo-induced in-situ crosslinking to simultaneously address the multiple needs of small molecule collagen peptide activity retention, improved wash fastness, fiber mechanical reinforcement, and rapid release of efficacy within the same process system. Therefore, this paper proposes a small molecule collagen peptide core-shell nanofiber skin care fabric and its preparation method to solve these problems. Summary of the Invention

[0007] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a small molecule collagen peptide core-shell nanofiber skincare fabric and its preparation method, thus solving the problems mentioned in the background section.

[0008] Technical solution To achieve the above objectives, the present invention is implemented through the following technical solution: a small molecule collagen peptide core-shell nanofiber skin care fabric, which is formed by stacking photocrosslinked nanofibers with a core-shell structure, wherein the core-shell structured nanofibers have a photocrosslinkable polymer as the core layer and a small molecule collagen peptide grafted with photosensitive groups as the shell layer.

[0009] The photocrosslinkable polymer is a continuous phase fiber skeleton matrix. On the one hand, it serves as the main load-bearing structure of the fiber, providing the basic mechanical support, flexibility, and dimensional stability required by the fabric. On the other hand, its molecular chains are grafted with unsaturated double bonds that can participate in crosslinking reactions. It can not only undergo interfacial reactions with the photosensitive groups of small molecule collagen peptides in the shell, but also undergo intermolecular self-crosslinking under light conditions. This is the structural basis for achieving both mechanical reinforcement and interfacial anchoring effects.

[0010] The small-molecule collagen peptides grafted with photosensitive groups serve as the surface functional phase of the fiber. The small-molecule collagen peptide molecules themselves possess corresponding skin care active effects, such as moisturizing and repairing, and are the main source of the fabric's functional value. The photosensitive groups grafted onto the sides of the small-molecule collagen peptides provide active sites for photo-triggered reactions. They can form covalent bonds with the double bonds of the core polymer under mild light conditions, without the need for harsh conditions such as high temperature or strong chemical reagents, thus preserving the natural skin care activity of the small-molecule collagen peptides to the greatest extent.

[0011] This core-shell structured nanofiber achieves precise nanoscale forming through coaxial electrospinning technology. Coaxial electrospinning employs nested coaxial needles, with the core and shell spinning solutions extruded simultaneously from the inner and outer needles, respectively. Under a high-voltage electric field, the composite jet is continuously stretched and refined, accompanied by rapid solvent evaporation, ultimately solidifying to form nanofibers with a clear core-shell hierarchical structure. By controlling the flow rate, ratio, and spinning parameters of the inner and outer fluids, the core diameter and shell thickness can be precisely controlled, enabling controllable fabrication of nanoscale structures.

[0012] By placing small-molecule collagen peptides in the fiber shell rather than dispersing them within the matrix, the two aspects are as follows: First, the small-molecule collagen peptides are directly exposed on the fiber surface, allowing them to act directly on the skin when the fabric comes into contact with it, without the need for slow diffusion from within the matrix. This solves the problems of delayed release of efficacy and low utilization rate of effective ingredients in existing embedded small-molecule collagen peptide fibers. Second, the independent phase formation of small-molecule collagen peptides avoids problems such as high-temperature shearing and poor compatibility when blended with polymer matrices, reducing the risk of small-molecule collagen peptide inactivation and fiber mechanical degradation from the source of the process.

[0013] After photo-initiated in-situ crosslinking, the core-shell nanofibers undergo two types of crosslinking reactions simultaneously, forming a synergistic effect. The first type is the covalent crosslinking reaction at the core-shell interface: photosensitive groups on the small-molecule collagen peptides in the shell layer are excited by light to generate active intermediates, which undergo addition reactions with the unsaturated double bonds on the surface of the core layer polymer, forming stable covalent chemical bonds at the core-shell interface. This firmly anchors the small-molecule collagen peptide molecules to the fiber backbone, replacing the traditional physical embedding method and solving the industry pain points of easy dissolution and poor wash resistance of small-molecule collagen peptides. The second type is the bulk crosslinking reaction within the core layer: unsaturated double bonds on the polymer molecular chains in the core layer undergo intermolecular crosslinking polymerization under light irradiation, forming a three-dimensional network crosslinked structure. This enhances the fiber's cohesive strength and resistance to deformation, offsetting the negative impact of introducing functional components on mechanical properties, achieving simultaneous functional enhancement and mechanical strengthening.

[0014] The two types of cross-linking reactions are triggered simultaneously through the same light irradiation process, eliminating the need for step-by-step processing and making the process simple and efficient. Furthermore, the interfacial cross-linking and bulk cross-linking promote each other. The interfacial covalent bonding enhances the bonding stability of the core and shell layers, preventing shell detachment. The bulk cross-linking enhances the structural strength of the core framework, providing a more stable base for interfacial anchoring. The synergistic effect of the two ultimately achieves multiple benefits, including firm anchoring of small molecule collagen peptides, improved fiber mechanics, and long-lasting retention of activity.

[0015] Preferably, the photocrosslinkable polymer is selected from one or a combination of two of polyvinyl alcohol-methacrylate and polycaprolactone-acrylate. Polyvinyl alcohol-methacrylate is obtained by modifying polyvinyl alcohol through methacrylate conversion. It possesses excellent biocompatibility and skin affinity, is non-irritating to the skin, and is suitable for the use of close-fitting functional fabrics. The hydroxyl groups on its molecular chain provide good hydrophilicity and moisturizing properties, while the grafted methacrylate double bonds provide ample photocrosslinking reaction sites. The three-dimensional network structure formed after crosslinking exhibits both good mechanical strength and dimensional stability. Polycaprolactone-acrylate possesses excellent flexibility, flexural strength, and water resistance. After film formation, it is soft and elastic, providing the fabric with a good feel and washability. Its acrylate groups have moderate reactivity, and the photocrosslinking reaction is highly controllable. Both can be used alone or compounded in proportion. By adjusting the ratio, the skin affinity, mechanical strength, and water resistance of the fabric can be balanced to suit different application scenarios.

[0016] Preferably, the photosensitive group is selected from one or a combination of two of phenyl azide and benzophenone. The phenyl azide group decomposes under ultraviolet light irradiation, releasing nitrogen gas and generating a highly reactive nitrogen-containing intermediate. This intermediate can rapidly undergo addition reactions with carbon-carbon double bonds and carbon-hydrogen bonds, exhibiting high reaction efficiency and mild conditions. The reaction can be completed quickly at room temperature, and no small-molecule toxic byproducts remain, making it suitable for the fixation of skincare active ingredients. The benzophenone group forms a diradical under ultraviolet light excitation, capable of abstracting hydrogen atoms from the polymer molecular chain and forming covalent bonds. This reaction exhibits good stability and minimal impact on the main chain structure of small-molecule collagen peptides, maximizing the preservation of their skincare activity. Both types of photosensitive groups can be grafted onto the active sites such as amino and carboxyl groups on the side chains of small-molecule collagen peptides. The grafting sites can be selected at the inactive ends of the small-molecule collagen peptides to avoid affecting the functional domains of the peptides, ensuring that the modified small-molecule collagen peptides retain their complete biological efficacy.

[0017] Preferably, the core-shell structured nanofiber has a core diameter of 200–400 nm and a shell thickness of 50–100 nm. Setting the core diameter within the 200–400 nm range represents a reasonable range for balancing overall mechanical properties and nano-effects. If the core diameter is less than 200 nm, the fiber is too thin, resulting in insufficient load-bearing capacity of the core skeleton, making it difficult to meet the tensile and abrasion resistance requirements of the fabric even after cross-linking. If the core diameter is greater than 400 nm, the fiber loses the advantages of high specific surface area and high porosity of nanofibers, leading to decreased breathability and skin feel of the fabric, and a reduced relative proportion of small-molecule collagen peptides in the shell, resulting in a smaller effective contact area. Setting the shell thickness within the 50–100 nm range represents a reasonable range for balancing the loading capacity and binding stability of small-molecule collagen peptides. If the shell thickness is less than 50nm, the total amount of small molecule collagen peptides that can be loaded is limited, making it difficult to achieve the target efficacy concentration. If the shell thickness is greater than 100nm, the small molecule collagen peptides inside the shell are difficult to form an effective covalent bond with the core layer. The small molecule collagen peptides near the surface are not effectively anchored and are easily detached and lost during washing. In addition, an excessively thick shell will lead to a decrease in jet stability during spinning, and the fiber morphology is prone to defects such as beading and uneven thickness.

[0018] Preferably, the total loading of the small molecule collagen peptides in the fiber is 15–30 wt%. Setting the loading of small molecule collagen peptides within this range balances the functional effectiveness and structural stability of the fabric. When the loading is below 15 wt%, the concentration of small molecule collagen peptides on the fiber surface is insufficient, resulting in a low effective dose upon skin contact, making it difficult to achieve the expected biological efficacy and failing to realize the value of the functional fabric. When the loading is above 30 wt%, on the one hand, the shell layer accounts for too large a proportion, resulting in insufficient interfacial bonding area between the core and shell structures, a decrease in overall bonding strength after cross-linking, and a tendency for the shell layer to peel off in whole pieces; on the other hand, the viscosity and rheological properties of the high-concentration small molecule collagen peptide spinning solution are difficult to match the requirements of coaxial spinning, easily leading to problems such as needle blockage and jet breakage, decreased spinning stability, and poor fiber morphological uniformity. The loading range of 15–30 wt% ensures that there are sufficient small molecule collagen peptides on the fiber surface to exert their effects, while also guaranteeing the molding stability of the core-shell structure and the bonding strength after cross-linking.

[0019] Preferably, after photo-initiated in-situ crosslinking, the fiber's tensile strength is 8–12 cN / dtex, and the retention rate of small molecule collagen peptides after 50 standard washes is ≥92%. This performance indicator reflects the final effect of the synergistic technical solution of this invention. A tensile strength of 8–12 cN / dtex, more than 60% higher than that of uncrosslinked core-shell fibers, fully meets the mechanical requirements for textile fabrics, can withstand the external forces during daily wear, washing, and friction, and is less prone to fiber breakage and pilling. The retention rate of small molecule collagen peptides after 50 standard washes is ≥92%, higher than the typically less than 60% retention rate of traditional physical blending and physical coating systems. This means that the fabric can still retain most of the effective small molecule collagen peptide components after long-term repeated washing, improving the durability of its efficacy. This performance level cannot be achieved through a single technical means; it is the result of the synergistic effect of core-shell structure design, interfacial covalent anchoring, and core layer bulk reinforcement.

[0020] This invention also provides a method for preparing a small-molecule collagen peptide core-shell nanofiber skincare fabric, comprising the following steps: Step 1, adding a photocrosslinkable polymer to a corresponding solvent, stirring until completely dissolved, and obtaining a core-layer spinning solution after filtration and degassing. Step 2, adding small-molecule collagen peptides grafted with photosensitive groups to a corresponding solvent, stirring until uniformly dispersed, and obtaining a shell-layer spinning solution after filtration and degassing. Step 3, loading the core-layer spinning solution and the shell-layer spinning solution into corresponding feeding devices of a coaxial electrospinning device, and performing coaxial electrospinning at room temperature to collect a primary core-shell nanofiber membrane on a receiving substrate. Step 4, irradiating the primary core-shell nanofiber membrane under ultraviolet or visible light to initiate an in-situ crosslinking reaction, and obtaining the finished functional fabric after curing and shaping.

[0021] This preparation method primarily operates at room temperature / low temperature, without high-temperature melting or curing processes. This avoids denaturation and inactivation of small-molecule collagen peptides due to high temperatures during processing, providing the technological basis for achieving high activity retention of small-molecule collagen peptides. Furthermore, the seamless integration of each process allows for continuous production of spinning, forming, and cross-linking curing, meeting the demands of industrial-scale mass production.

[0022] Steps one and two are the spinning solution preparation processes, where core-layer and shell-layer spinning solutions are prepared independently. Suitable solvents and dissolution conditions can be selected based on the characteristics of the two types of materials. The core-layer polymer spinning solution is filtered to remove undissolved impurities and gel particles, preventing clogging of the spinning needles during spinning. A degassing treatment removes micro-air bubbles from the solution, preventing interruptions in the spinning jet, fiber breakage, and uneven fiber thickness, ensuring the continuity and uniformity of fiber formation. The shell-layer small-molecule collagen peptide spinning solution is prepared under gentle stirring conditions to avoid high-speed shearing damaging the spatial structure of the small-molecule collagen peptides, ensuring that the small-molecule collagen peptides retain their complete skin-care activity before spinning.

[0023] Step three is the coaxial electrospinning process, a crucial step in realizing core-shell structured nanofibers. A precision propulsion device controls the delivery rates of the spinning solutions for the core and shell layers, allowing the two fluids to form a stable coaxial composite jet at the exit of the coaxial needle. Under the electrostatic force provided by a high-voltage electric field, the composite jet is continuously stretched and refined, while the solvent rapidly evaporates at room temperature, ultimately depositing a core-shell structured nanofiber membrane onto the receiving substrate. The entire spinning process is conducted at room temperature, eliminating the need for heating and preventing the degradation of small-molecule collagen peptide activity by high temperatures.

[0024] Step four is the photo-initiated in-situ curing process, a crucial step in achieving covalent anchoring and mechanical reinforcement. The formed primary fiber membrane is directly placed in a light environment, triggering both interfacial and bulk crosslinking reactions in a single irradiation step. No additional chemical crosslinking agents or high-temperature treatment are required, and the reaction conditions are mild and controllable. By adjusting the light irradiation parameters, the degree of crosslinking can be precisely controlled. While ensuring sufficient crosslinking, the impact of light on the activity of small-molecule collagen peptides is minimized, ultimately resulting in a structurally stable and high-performance finished functional fabric.

[0025] Preferably, in step three, the core-shell propulsion rate of coaxial electrospinning is 0.2–0.8 mL / h, the shell-shell propulsion rate is 0.1–0.5 mL / h, the spinning voltage is 12–20 kV, and the receiving distance is 10–20 cm. The propulsion rates of the core and shell layers directly determine the size ratio and molding stability of the core-shell structure. Setting the core-shell propulsion rate to 0.2–0.8 mL / h and the shell-shell propulsion rate to 0.1–0.5 mL / h maintains a higher ratio between the core-shell and shell-shell rates, ensuring the core layer's dominant position as the framework while also meeting the shell's thickness requirement of 50–100 nm. If the propulsion rate is too low, the spinning efficiency is too low, resulting in poor mass production; if the propulsion rate is too high, the jet stretching is insufficient, the fiber diameter is too coarse, and a beaded morphology is easily formed.

[0026] Setting the spinning voltage to 12–20 kV is a reasonable range to ensure stable stretching of the jet. When the voltage is below 12 kV, the electric field force is insufficient, the jet cannot be fully stretched, the fiber diameter is coarse and the uniformity is poor, and droplet adhesion is likely to occur. When the voltage is above 20 kV, the electric field force is too strong, the jet is unstable, and splitting and scattering are likely to occur, the uniformity of the fiber membrane decreases, and there is a risk of breakdown discharge.

[0027] The receiving distance is set to 10–20 cm to match the requirements of solvent evaporation and fiber curing. If the receiving distance is too short, the solvent will not evaporate sufficiently, and the fiber will remain in a viscous flow state during deposition, making it prone to adhesion and collapse, and easily damaging the core-shell structure. If the receiving distance is too long, the fiber will drift excessively during flight, resulting in low deposition efficiency and reduced density and uniformity of the fiber membrane. This range ensures sufficient solvent evaporation and complete fiber curing, while maintaining high deposition efficiency and membrane uniformity.

[0028] Preferably, in step four, the irradiation wavelength is 254–405 nm, the light power is 50–200 W, and the irradiation time is 2–15 min. The irradiation wavelength matches the characteristic absorption peaks of the photosensitive groups. Phenylated azide and benzophenone both have strong absorption in the ultraviolet-near-ultraviolet band of 254–405 nm, which can efficiently excite the photoreaction and avoid ineffective irradiation. The light power and irradiation time together determine the total irradiation dose. If the total dose is too low, the cross-linking reaction will be insufficient, and the interfacial bonding force and mechanical strength will not reach the target level; if the total dose is too high, it will cause photodegradation of the small molecule collagen peptide molecular chains, leading to a decrease in skin care activity, as well as energy waste and reduced production efficiency. A power of 50–200 W combined with an irradiation time of 2–15 min can maintain the small molecule collagen peptide activity retention rate above 90% while the cross-linking reaction reaches saturation, achieving a balance between cross-linking efficiency and activity retention.

[0029] Preferably, the receiving substrate in step three is one of nonwoven fabric, woven fabric, or spunlace fabric, and the surface density of the collected primary core-shell nanofiber membrane is 10–50 g / m². Different receiving substrates can be adapted to different product positioning and application scenarios. Nonwoven fabric substrates have low cost, high porosity, and good breathability, making them suitable for disposable functional masks and dressings; woven fabric substrates have high mechanical strength and good stiffness, making them suitable for clothing fabrics; spunlace fabric substrates have a soft feel and good skin-friendliness, making them suitable for close-fitting skincare fabrics. Setting the surface density to 10–50 g / m² balances the fabric's functionality, breathability, and wearing comfort. If the surface density is too low, the fiber membrane is too thin, resulting in insufficient total loading of small molecule collagen peptides and a short duration of efficacy; if the surface density is too high, the fiber membrane is too thick, reducing breathability and causing a stuffy feeling when worn close to the skin, and also reducing the fabric's flexibility and worsening the skin feel.

[0030] Beneficial effects The present invention has the following beneficial effects: (1) The small molecule collagen peptide core-shell nanofiber skin care fabric and its preparation method, through the combination of core-shell structure design, photo-induced in-situ crosslinking mechanism and mild preparation process, solves the problems of easy loss of activity, poor wash fastness, insufficient mechanical strength and slow release of efficacy of existing small molecule collagen peptide electrospun fibers. It achieves simultaneous improvement of small molecule collagen peptide activity retention, wash fastness, mechanical properties and release efficiency. The prepared functional fabric is suitable for multiple scenarios such as skin care textiles and medical dressings.

[0031] (2) The small molecule collagen peptide core-shell nanofiber skin care fabric and its preparation method adopt the photo-initiated in-situ cross-linking mechanism. Two types of cross-linking reactions are achieved simultaneously through one-step light irradiation. After the photosensitive groups of the shell are excited, they form covalent bonds with the unsaturated double bonds of the core polymer, anchoring the small molecule collagen peptides on the fiber skeleton and improving wash fastness. Simultaneously, the core polymer undergoes intermolecular cross-linking to form a network structure, which improves the overall mechanical properties of the fiber and offsets the negative impact of the introduction of functional components on mechanics.

[0032] (3) The small molecule collagen peptide core-shell nanofiber skin care fabric and its preparation method adopt a combination of room temperature coaxial spinning and room temperature light crosslinking. The entire process does not require high temperature melting and high temperature curing. The reaction conditions are mild. While achieving covalent bonding and mechanical enhancement, it can retain the skin care activity of small molecule collagen peptides, taking into account both functional effectiveness and structural stability.

[0033] (4) The small molecule collagen peptide core-shell nanofiber skin care fabric and its preparation method adopt a core-shell structure fiber design, and set the small molecule collagen peptide grafted with photosensitive groups as the fiber shell layer. After the small molecule collagen peptide is formed independently, it does not need to be blended with the core layer polymer, thus avoiding the shear damage and high temperature effect during the blending spinning process. At the same time, the small molecule collagen peptide is directly exposed on the fiber surface and can play a direct role when in contact with the skin, thereby improving the efficacy release efficiency and ingredient utilization rate.

[0034] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0035] Figure 1 This is a flowchart illustrating the small molecule collagen peptide core-shell nanofiber skincare fabric and its preparation method according to the present invention. Detailed Implementation

[0036] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1 This embodiment provides a small molecule collagen peptide core-shell nanofiber skincare fabric, the preparation method of which is as follows: Figure 1 As shown, the specific preparation steps are as follows: Step 1, Core spinning solution preparation: Polyvinyl alcohol-methacrylate is added to a solvent containing deionized water and anhydrous ethanol at a volume ratio of 7:3. The mixture is stirred at room temperature until completely dissolved to prepare a homogeneous solution with a mass fraction of 12%. After filtration through a filter membrane and vacuum standing to remove bubbles, the core spinning solution is obtained. Step 2, Shell spinning solution preparation: Small molecule collagen peptides grafted with phenyl azide groups are added to a phosphate buffer solution with a pH of 7.4. The mixture is stirred at low speed until completely dispersed to prepare a small molecule collagen peptide solution with a mass fraction of 8%. After filtration through a filter membrane and vacuum standing to remove bubbles, the shell spinning solution is obtained. Step 3, Coaxial Electrospinning: The core-shell spinning solution and the shell-shell spinning solution are respectively loaded into the corresponding feeding devices of the coaxial electrospinning equipment. The core-shell feed rate is set to 0.8 mL / h, the shell-shell feed rate to 0.5 mL / h, the spinning voltage to 20 kV, the receiving distance to 20 cm, and the receiving substrate to be spunlace nonwoven fabric. Continuous spinning is performed at room temperature to collect the primary core-shell nanofiber membrane, with a membrane surface density of 50 g / m². Step 4, Photo-Initiated In-Situ Crosslinking and Curing: The primary core-shell nanofiber membrane is laid flat in a light irradiation device and irradiated with visible light at a wavelength of 405 nm. The light power is set to 200 W, and the irradiation time is 15 min. After irradiation, the membrane is removed to obtain the finished functional fabric.

[0038] The functional fabric prepared in this embodiment has a core-shell structure in its constituent fibers, with a core diameter of 400 nm, a shell thickness of 100 nm, and a loading of 30 wt% of small molecule collagen peptides in the fibers.

[0039] Example 2 This embodiment provides a small molecule collagen peptide core-shell nanofiber skincare fabric. The specific preparation steps are as follows: Step 1, Core layer spinning solution preparation: Polycaprolactone-acrylate is added to a solvent containing N,N-dimethylformamide and dichloromethane at a volume ratio of 4:6. The mixture is stirred at room temperature until completely dissolved to prepare a homogeneous solution with a mass fraction of 10%. After filtration through a filter membrane and vacuum standing to remove bubbles, the core layer spinning solution is obtained. Step 2, Shell layer spinning solution preparation: Small molecule collagen peptides grafted with benzophenone groups are added to a hexafluoroisopropanol aqueous solution and stirred at low speed until completely dispersed to prepare a small molecule collagen peptide solution with a mass fraction of 6%. After filtration through a filter membrane and vacuum standing to remove bubbles, the shell layer spinning solution is obtained. Step 3, Coaxial Electrospinning: The core-shell spinning solution and the shell-shell spinning solution are respectively loaded into the corresponding feeding devices of the coaxial electrospinning equipment. The core-shell feed rate is set to 0.2 mL / h, the shell-shell feed rate to 0.1 mL / h, the spinning voltage to 12 kV, the receiving distance to 10 cm, and the receiving substrate to polypropylene nonwoven fabric. Continuous spinning is performed at room temperature to collect the primary core-shell nanofiber membrane, with a membrane surface density of 10 g / m². Step 4, Photo-Initiated In-Situ Crosslinking and Curing: The primary core-shell nanofiber membrane is laid flat in a light irradiation device and irradiated with ultraviolet light at a wavelength of 254 nm. The light power is set to 50 W, and the irradiation time is 2 min. After irradiation, the membrane is removed to obtain the finished functional fabric.

[0040] The functional fabric prepared in this embodiment has a core-shell structure in its constituent fibers, with a core diameter of 200 nm, a shell thickness of 50 nm, and a loading of 15 wt% of small molecule collagen peptides in the fibers.

[0041] Comparative Example 1 This comparative example uses a functional fabric made from small-molecule collagen peptides, prepared using a blended electrospinning process without photocrosslinking. The specific steps are as follows: Polyvinyl alcohol-methacrylate and unmodified photosensitive small-molecule collagen peptides are added to a mixed solvent of deionized water and anhydrous ethanol at a mass ratio of 7:3. The mixture is stirred until completely dissolved, preparing a blended spinning solution with a total solute mass fraction of 12%. After filtration through a filter membrane and vacuum degassing, uniaxial electrospinning is performed. The feed rate is set to 1.3 mL / h, the spinning voltage to 20 kV, the receiving distance to 20 cm, and the receiving substrate to be spunlace nonwoven fabric. The finished fabric is obtained directly after spinning without photocrosslinking.

[0042] In this comparative example, the total loading of small molecule collagen peptides is 30 wt%, consistent with that in Example 1.

[0043] Comparative Example 2 This comparative example uses a small molecule collagen peptide functional fabric, prepared using a coaxial electrospinning process without photocrosslinking treatment. The specific steps are as follows: the formulation and operation of the core layer spinning solution and shell layer spinning solution are completely consistent with those in Example 1. The process parameters of coaxial electrospinning are exactly the same as those in Example 1. After obtaining the primary core-shell nanofiber membrane, no photocrosslinking step is performed, and it is directly used as the finished fabric.

[0044] In this comparative example, the total loading of small molecule collagen peptides was 30 wt%, and the core-shell size of the fibers was basically the same as that in Example 1.

[0045] Experimental Example 1: Fabric Tension Strength Test Test standard: GB / T3923.1-2013 "Textiles - Tensile properties of fabrics - Part 1: Determination of breaking strength and elongation at break (strip method)" Experimental objective: To test the tensile breaking strength of functional fabrics prepared by different methods, and to compare and evaluate the mechanical performance level of each method.

[0046] Experimental Procedure: Samples from Example 1, Example 2, Comparative Example 1, and Comparative Example 2 were cut into rectangular strips 50 mm wide and 200 mm long. The clamping distance of the electronic strength tester was set to 100 mm, and the tensile rate was 100 mm / min. Five parallel specimens were prepared for each group of samples. After testing, the average value was taken to calculate the breaking strength, and the results are recorded in the table below:

[0047] As shown in the table above, the tensile strength of both sets of example samples is higher than that of the two sets of comparative samples. After photocrosslinking treatment, the core polymer of the example samples forms a crosslinked network structure, which improves the cohesive strength of the fibers. The overall mechanical properties of the fibers in the uncrosslinked comparative samples are relatively low. Among them, the small molecule collagen peptides in the blend system are dispersed inside the matrix, and their influence on mechanical properties is slightly lower than that of the purely physically coated coaxial comparative sample 2. This method, through photo-initiated in-situ crosslinking, can improve the mechanical properties of fibers while loading small molecule collagen peptides, which can meet the basic mechanical requirements of conventional apparel fabrics. Experiment Example 2: Water Wash Resistance Test of Small Molecule Collagen Peptides Test standard: GB / T8629-2017 "Home washing and drying procedures for testing textiles", using the 5A washing program. Experimental objective: To test the retention of small molecule collagen peptides in fabrics after multiple standard washes, and to compare and evaluate the wash fastness of small molecule collagen peptides in different methods.

[0048] Experimental Procedure: Samples from Examples 1, 2, Comparative Example 1, and 2 were cut to the same size. The initial small molecule collagen peptide content of each sample was determined using high-performance liquid chromatography (HPLC). Subsequently, the samples were washed 50 times according to a standard washing procedure, followed by standard drying after each wash. After all washing was completed, the remaining small molecule collagen peptide content in the samples was tested again, and the small molecule collagen peptide retention rate was calculated as (remaining small molecule collagen peptide mass / initial small molecule collagen peptide mass × 100%). Three parallel samples were set up for each group, and the average results were recorded in the table below.

[0049] As shown in the table above, after 50 standard washes, the retention rates of small molecule collagen peptides in the two comparative samples were relatively low. Comparative Example 2, with its physically encapsulated coaxial structure, exhibited the largest loss of small molecule collagen peptides during washing, as there were no chemical bonds between the shell layer and the core layer. Comparative Example 1, with its small molecule collagen peptides embedded within the fiber matrix, experienced slightly less loss than Comparative Example 2, but still saw a significant amount dissolved during washing. This proposed method utilizes photo-initiated in-situ crosslinking to form covalent bonds between the small molecule collagen peptides and the core polymer, thereby reducing the loss of small molecule collagen peptides during washing and extending the effective lifespan of the fabric's function.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0051] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A small molecule collagen peptide core-shell nanofiber skincare fabric, characterized in that, It is formed by stacking photocrosslinked nanofibers with a core-shell structure, wherein the core-shell structured nanofibers have a photocrosslinkable polymer as the core layer and a small molecule collagen peptide grafted with photosensitive groups as the shell layer. The photocrosslinkable polymer is a continuous phase fiber skeleton matrix that provides basic mechanical support and contains unsaturated double bonds that can participate in crosslinking reactions; The small molecule collagen peptides grafted with photosensitive groups are the surface functional phase, which endows the fabric with skin care active effects and has photo-triggerable reaction sites. After the core-shell structured nanofibers are photo-initiated and cross-linked in situ, the small molecule collagen peptides in the shell layer form covalent bonds with the unsaturated double bonds of the core layer polymer through photosensitive groups. At the same time, the core layer polymer itself cross-links to form a three-dimensional network structure. The synergistic effect of the two makes the small molecule collagen peptides firmly anchored on the fiber surface, simultaneously improving the mechanical strength of the fiber and the wash fastness of the small molecule collagen peptides, and ensuring the immediate release of the skin care activity of the small molecule collagen peptides.

2. The small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 1, characterized in that, The photocrosslinkable polymer is selected from one or a combination of two of polyvinyl alcohol-methacrylate and polycaprolactone-acrylate.

3. The small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 1, characterized in that, The photosensitive group is selected from one or a combination of two of phenyl azide and benzophenone.

4. The small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 1, characterized in that, The core-shell structured nanofibers have a core diameter of 200–400 nm and a shell thickness of 50–100 nm.

5. The small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 1, characterized in that, The loading amount of the small molecule collagen peptide in the fiber is 15-30 wt%.

6. The small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 1, characterized in that, After photo-initiated in-situ cross-linking, the fiber breaking strength is 8-12 cN / dtex, and the retention rate of small molecule collagen peptides after 50 standard washes is ≥92%.

7. A method for preparing small molecule collagen peptide core-shell nanofiber skincare fabric, characterized in that, The method for preparing the small molecule collagen peptide core-shell nanofiber skin care fabric according to any one of claims 1 to 6 includes the following steps: Step 1: Add the photocrosslinkable polymer to the corresponding solvent, stir until completely dissolved, and obtain the core spinning solution after filtration and degassing. Step 2: Add the small molecule collagen peptides grafted with photosensitive groups to the corresponding solvent, stir until uniformly dispersed, and obtain the shell spinning solution after filtration and degassing. Step 3: The core spinning solution and the shell spinning solution are respectively loaded into the corresponding feeding devices of the coaxial electrospinning equipment, and coaxial electrospinning is carried out at room temperature. The primary core-shell nanofiber membrane is collected on the receiving substrate. Step four: Irradiate the primary core-shell nanofiber membrane under ultraviolet or visible light to initiate an in-situ cross-linking reaction, and obtain the finished functional fabric after curing and shaping.

8. The method for preparing the small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 7, characterized in that, In step three, the core advance rate of coaxial electrospinning is 0.2–0.8 mL / h, the shell advance rate is 0.1–0.5 mL / h, the spinning voltage is 12–20 kV, and the receiving distance is 10–20 cm.

9. The method for preparing the small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 7, characterized in that, In step four, the irradiation wavelength is 254–405 nm, the light power is 50–200 W, and the irradiation time is 2–15 min.

10. The method for preparing the small molecule collagen peptide core-shell nanofiber skincare fabric according to claim 7, characterized in that, The receiving substrate in step three is one of nonwoven fabric, woven fabric or spunlace fabric, and the surface density of the primary core-shell nanofiber membrane collected is 10-50 g / m².

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