An antibacterial, long-lasting, skin-friendly sanitary napkin and its preparation method

Abstract

This invention discloses a long-lasting antibacterial, skin-friendly sanitary napkin and its preparation method, belonging to the technical field of disposable hygiene products. The sanitary napkin, from top to bottom, consists of a skin-friendly surface layer, a diversion layer, an absorbent core, a leak-proof bottom layer, and a release paper. The skin-friendly surface layer is treated with a chitosan-permeable solution, high-pressure impregnation at 10-20 MPa for 1 hour. The chitosan-permeable solution is a compound of 4-6% chitosan solution, 20-25% modified hydroxyapatite, and 8-12% sodium alginate. This invention achieves deep penetration of antibacterial components through high-pressure impregnation, combined with the sustained-release effect of modified hydroxyapatite and the skin-friendly soothing effect of sodium alginate, giving the sanitary napkin advantages such as long-lasting antibacterial effect, long-lasting skin-friendliness, breathability, backflow prevention, and safety without irritation.

Description

Technical Field

[0001] This invention relates to the field of sanitary napkin technology, specifically to an antibacterial, long-lasting, skin-friendly sanitary napkin and its preparation method. Background Technology

[0002] Sanitary napkins are essential disposable hygiene products for women during menstruation, and their core performance directly affects the user experience and health safety. Traditional sanitary napkins mostly use cotton or non-woven fabric as the surface layer. Although they have a certain degree of skin-friendliness, they have problems such as weak antibacterial ability, easy growth of bacteria and mold, poor breathability, easy odor, and short-lasting antibacterial effect. Some products add chemical antibacterial agents, which can easily cause skin allergies and irritation, and long-term use poses health risks. At the same time, the skin-friendly layer and absorbent core of ordinary sanitary napkins have poor bonding, and menstrual blood is prone to backflow and side leakage, affecting the comfort of use.

[0003] Existing antibacterial sanitary napkins mostly use antibacterial agents such as silver ions and quaternary ammonium salts, which have drawbacks such as high cost, easy precipitation, insufficient antibacterial durability, and decreased skin affinity. Although chitosan has advantages such as natural antibacterial properties, skin affinity, and good biocompatibility, simple chitosan solution impregnation treatment has problems such as insufficient penetration depth, weak binding force, short antibacterial effect, and poor water resistance, making it difficult to meet the requirements of long-lasting antibacterial and long-lasting skin affinity for sanitary napkins.

[0004] How to achieve a combination of long-lasting antibacterial properties, skin-friendly properties, breathability, backflow prevention, and safety and non-irritation in sanitary napkins by deeply impregnating and modifying them with chitosan-based penetrants, combined with the synergistic effect of modified hydroxyapatite and sodium alginate, has become a technical problem that the industry urgently needs to solve. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the purpose of this invention is to provide an antibacterial, long-lasting, skin-friendly sanitary napkin and its preparation method, so as to solve the problems mentioned in the background art.

[0006] The present invention solves the technical problem by adopting the following technical solution: This invention provides an antibacterial, long-lasting, skin-friendly sanitary napkin, comprising, from top to bottom: a skin-friendly surface layer, a diversion layer, an absorbent core, a leak-proof bottom layer, and a release paper; the skin-friendly surface layer is treated with a chitosan permeation solution, with a permeation pressure of 10-20 MPa and a permeation time of 1 hour; the chitosan permeation solution is prepared by the following method: adding 20-25% modified hydroxyapatite and 8-12% sodium alginate to a chitosan solution with a mass fraction of 4-6%, and stirring thoroughly to obtain the chitosan permeation solution.

[0007] Preferably, the skin-friendly surface layer is made of pure cotton nonwoven fabric, spunlace nonwoven fabric, or bamboo fiber nonwoven fabric; the diversion layer is made of hot air nonwoven fabric; the absorbent core is made of a composite core of superabsorbent polymer and wood pulp fiber; the leak-proof bottom layer is made of breathable PE film; and the release paper is made of glassine paper.

[0008] Preferably, the modified hydroxyapatite is prepared by the following steps: S1: preheating hydroxyapatite at 55-60℃ for 1 hour to obtain preheated hydroxyapatite; S2: stirring the preheated hydroxyapatite and the modification liquid at a weight ratio of 3:(5-7) for 1 hour at a stirring speed of 350-400 r / min; S3: after stirring, filtering and drying to obtain modified hydroxyapatite; wherein, the modification liquid is prepared by fully mixing sodium silicate solution, silane coupling agent KH550 and nano calcium carbonate at a weight ratio of (5-8):(1-3):2.

[0009] Preferably, the sodium alginate agent is prepared by the following method: a sodium alginate solution with a mass fraction of 5-8%, glycolic acid and citric acid are mixed thoroughly in a weight ratio of (5-8):4:(1-3) to prepare the sodium alginate agent.

[0010] This invention also provides a method for preparing an antibacterial, long-lasting, skin-friendly sanitary napkin, comprising the following steps: S100: Skin-friendly surface layer pretreatment: The skin-friendly surface layer is placed in a chitosan permeation solution and immersed for 1 hour under a pressure of 10-20 MPa. After removal, it is dried at 50-60℃ until the moisture content is ≤8%, thus obtaining an antibacterial, skin-friendly surface layer; S200: Layered composite: The skin-friendly surface layer, the diversion layer, the absorbent core, and the leak-proof bottom layer are stacked sequentially and formed by hot pressing; S300: Auxiliary processing: Three-dimensional protective barriers are set on both sides of the composite layer, and release paper is laminated to the bottom of the leak-proof bottom layer. After slitting and packaging, an antibacterial, long-lasting, skin-friendly sanitary napkin is obtained.

[0011] Preferably, in step S200, the hot pressing temperature is 110-130℃ and the hot pressing pressure is 0.3-0.5MPa.

[0012] Compared with the prior art, the present invention has the following beneficial effects: This invention relates to a deep wetting modification of chitosan infiltration liquid: through high-pressure wetting at 10-20MPa, the chitosan infiltration liquid deeply penetrates into the interior of the skin-friendly surface fibers, rather than just adhering to the surface, greatly improving the antibacterial durability and binding force, avoiding the rapid loss of antibacterial components, and achieving long-lasting antibacterial effect.

[0013] Synergistic effect of modified hydroxyapatite: Hydroxyapatite modified by sodium silicate, KH550 and nano calcium carbonate has significantly improved dispersibility and compatibility, can be loaded with chitosan to enhance antibacterial effect, and at the same time improve the moisture absorption, breathability, liquid absorption and structural stability of the skin-friendly surface, and reduce backflow.

[0014] Sodium alginate optimizes performance: Sodium alginate, when combined with glycolic acid and citric acid, can adjust the pH of chitosan solution, improve chitosan solubility and film-forming properties, enhance the wettability of the penetrating liquid on fibers, and at the same time impart moisturizing, soothing, and anti-irritant effects to the skin-friendly layer, improving skin comfort and reducing the risk of allergies.

[0015] Multiple synergies result in superior overall performance: The natural antibacterial properties of chitosan, the enhanced load-bearing capacity of modified hydroxyapatite, and the skin-friendly and soothing properties of sodium alginate work synergistically to give sanitary napkins advantages such as long-lasting antibacterial effect, long-lasting skin-friendliness, breathability and backflow prevention, and safety and non-irritation. It has a high antibacterial rate, long duration of action, good skin-friendliness, is suitable for sensitive skin, and has a stable process, making it suitable for industrial production. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the sanitary napkin of the present invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. 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.

[0018] This embodiment of an antibacterial, long-lasting, skin-friendly sanitary napkin includes, from top to bottom: a skin-friendly surface layer, a diversion layer, an absorbent core, a leak-proof bottom layer, and a release paper; the skin-friendly surface layer is treated with chitosan permeation liquid, with a permeation pressure of 10-20 MPa and a permeation time of 1 hour.

[0019] In this embodiment, the skin-friendly surface layer is made of pure cotton nonwoven fabric, spunlace nonwoven fabric, or bamboo fiber nonwoven fabric; the flow guiding layer is made of hot air nonwoven fabric; the absorbent core is made of a composite core of superabsorbent polymer and wood pulp fiber; the leak-proof bottom layer is made of breathable PE film; and the release paper is made of glassine paper.

[0020] The chitosan permeation solution of this embodiment is prepared by the following method: 20-25% of modified hydroxyapatite and 8-12% of sodium alginate are added to a chitosan solution with a mass fraction of 4-6%, and the mixture is stirred thoroughly to obtain the chitosan permeation solution.

[0021] The modified hydroxyapatite of this embodiment is prepared by the following steps: S1: preheating hydroxyapatite at 55-60℃ for 1 hour to obtain preheated hydroxyapatite; S2: stirring and modifying the preheated hydroxyapatite and the modification liquid at a weight ratio of 3:(5-7) with a stirring speed of 350-400 r / min for 1 hour; S3: after stirring, filtering and drying to obtain modified hydroxyapatite; wherein, the modification liquid is prepared by fully mixing sodium silicate solution, silane coupling agent KH550 and nano calcium carbonate at a weight ratio of (5-8):(1-3):2.

[0022] The sodium alginate agent of this embodiment is prepared by the following method: a sodium alginate solution with a mass fraction of 5-8%, glycolic acid and citric acid are mixed thoroughly in a weight ratio of (5-8):4:(1-3) to prepare the sodium alginate agent.

[0023] This embodiment describes a method for preparing an antibacterial, long-lasting, skin-friendly sanitary napkin, comprising the following steps: S100: Skin-friendly surface layer pretreatment: The skin-friendly surface layer is placed in a chitosan permeation solution and immersed for 1 hour under a pressure of 10-20 MPa. After removal, it is dried at 50-60°C until the moisture content is ≤8%, thus obtaining an antibacterial, skin-friendly surface layer; S200: Layered composite: The skin-friendly surface layer, the diversion layer, the absorbent core, and the leak-proof bottom layer are stacked sequentially and formed by hot pressing; S300: Auxiliary processing: Three-dimensional protective barriers are set on both sides of the composite layer, and release paper is laminated to the bottom of the leak-proof bottom layer. After slitting and packaging, an antibacterial, long-lasting, skin-friendly sanitary napkin is obtained.

[0024] In step S200 of this embodiment, the hot pressing temperature is 110-130℃ and the hot pressing pressure is 0.3-0.5MPa.

[0025] Example 1 An antibacterial and long-lasting skin-friendly sanitary napkin comprises, from top to bottom: a pure cotton spunlace nonwoven skin-friendly surface layer, a hot-air nonwoven absorbent layer, a superabsorbent polymer resin-wood pulp composite absorbent core, a breathable PE leak-proof bottom layer, and glassine release paper; the skin-friendly surface layer is impregnated with chitosan permeation liquid at 15MPa pressure for 1 hour and dried at 55℃ until the moisture content is ≤8%.

[0026] Chitosan permeation solution preparation Take 100 parts of a 5% (w / w) chitosan solution, add 22 parts of modified hydroxyapatite and 10 parts of sodium alginate, stir at 300 r / min for 30 min to obtain a chitosan permeation solution.

[0027] Preparation of modified hydroxyapatite S1: Hydroxyapatite was preheated at 58℃ for 1 hour; S2: Preheated hydroxyapatite:modifying solution = 3:6, stirred at 380 r / min for 1 hour; S3: Filtered and dried at 60℃ to obtain modified hydroxyapatite; wherein, the ratio of modifying solution:sodium silicate solution:KH550:nanocalcium carbonate = 6:2:2, was uniformly mixed.

[0028] Preparation of sodium alginate A sodium alginate solution with a mass fraction of 6% was prepared by mixing glycolic acid and citric acid in a ratio of 6:4:2.

[0029] Sanitary napkin preparation S100: Pure cotton spunlace nonwoven fabric is immersed in chitosan permeating liquid, impregnated at 15MPa pressure for 1 hour, and dried at 55℃ to a moisture content of 7%; S200: Skin-friendly surface layer, flow-guiding layer, absorbent core, and leak-proof bottom layer are stacked in sequence and hot-pressed at 120℃ and 0.4MPa; S300: Three-dimensional protective barrier is set, release paper is laminated, and the product is cut and packaged to obtain the finished product.

[0030] Example 2 The skin-friendly surface layer is made of bamboo fiber non-woven fabric, impregnated at a pressure of 10 MPa for 1 hour, and dried at 50°C. The chitosan permeation solution consists of 100 parts of 4% chitosan solution, plus 20 parts of modified hydroxyapatite and 8 parts of sodium alginate. The ratio of modified hydroxyapatite to preheated hydroxyapatite to modified solution is 3:5, and the mixture is stirred at 350 r / min for 1 hour. The modified solution ratio is 5:1:2. The sodium alginate solution ratio is 5% sodium alginate solution to glycolic acid to citric acid, which is 5:4:1. The preparation process is as follows: hot pressing temperature 110°C, pressure 0.3 MPa, and the rest is the same as in Example 1.

[0031] Example 3 The skin-friendly surface layer is made of pure cotton non-woven fabric, impregnated at a pressure of 20 MPa for 1 hour, and dried at 60°C. The chitosan permeation solution consists of 100 parts of 6% chitosan solution, plus 25 parts of modified hydroxyapatite and 12 parts of sodium alginate. The ratio of modified hydroxyapatite to preheated hydroxyapatite to modified solution is 3:7, and the mixture is stirred at 400 r / min for 1 hour. The modified solution ratio is 8:3:2. The sodium alginate solution ratio is 8% sodium alginate solution to glycolic acid to citric acid. The preparation process is as follows: hot pressing temperature 130°C, pressure 0.5 MPa, and the rest is the same as in Example 1.

[0032] Scale settings Referring to the process of Example 1, only the functional components were changed, and the rest were the same: Comparative Example 1: no chitosan permeation solution was used for impregnation, and only ordinary pure cotton surface was used; Comparative Example 2: ordinary chitosan solution (without added modified hydroxyapatite and sodium alginate) was used for impregnation treatment; Comparative Example 3: unmodified hydroxyapatite was used instead of modified hydroxyapatite; Comparative Example 4: ordinary sodium alginate solution (without added glycolic acid and citric acid) was used instead of sodium alginate; Comparative Example 5: chitosan permeation solution was impregnated under normal pressure (0 MPa), and the rest of the process was the same as in Example 1.

[0033] Performance testing Antibacterial properties were tested according to GB / T 20944.3-2008; absorbency and skin-friendliness of sanitary napkins were tested according to GB / T 8939-2018; hygiene indicators were tested according to GB 15979-2002; antibacterial durability was evaluated by the antibacterial rate after 5 washes; skin-friendliness was evaluated by the human skin irritation test score.

[0034] Table 1 Antibacterial performance (initial / after 5 washes, %) Table 2 Absorption and Skin-Friendliness Performance test results analysis I. Analysis of Antibacterial Properties and Durability Examples 1-3 demonstrate the long-lasting antibacterial effect of the core functional system. Initially, the inhibition rates against *Escherichia coli* and *Staphylococcus aureus* both reached over 99.2%, and after five washes, the inhibition rate remained above 98.1%, achieving long-lasting antibacterial effects. Comparative Example 1, without any antibacterial treatment, showed initial inhibition rates of only 62.3% and 65.1%, indicating no effective antibacterial ability. Comparative Example 2, using only ordinary chitosan solution, showed initial inhibition rates of only 90.5% and 91.2%, which plummeted to 76.2% and 77.5% after washing. This demonstrates that the combination of modified hydroxyapatite and sodium alginate significantly enhances the antibacterial activity and binding strength of chitosan, preventing the loss of antibacterial components.

[0035] The key role of modification treatment in antibacterial durability: Comparative Example 3 uses unmodified hydroxyapatite. Due to poor dispersibility and weak binding force with chitosan, the antibacterial rate after washing is only 72.4% and 73.6%, far lower than the examples. This indicates that the sodium silicate, KH550, and nano-calcium carbonate composite modification process of the present invention can significantly improve the dispersibility and loading capacity of hydroxyapatite, enhance the adhesion and sustained release of chitosan, and prolong the antibacterial effect. Comparative Example 4 uses ordinary sodium alginate solution without compounding. Lacking the pH adjustment and film-forming enhancement effects of glycolic acid and citric acid, the antibacterial rate after washing is only 78.6% and 79.3%. This indicates that the compounding of sodium alginate can optimize the solubility and film-forming properties of chitosan, improve the wetting and penetration effect, and enhance the antibacterial durability.

[0036] The core value of the high-pressure impregnation process: Comparative Example 5 uses atmospheric pressure impregnation, with an initial antibacterial rate of 93.4% and 94.1%, which is only 80.2% and 81.5% after washing, significantly lower than the example. This proves that high-pressure impregnation at 10-20MPa can allow chitosan to penetrate deeply into the fiber interior, rather than just adhering to the surface, greatly improving the binding force and durability of antibacterial components, and achieving true long-lasting antibacterial effect.

[0037] Example 3 shows the optimal antibacterial effect and durability due to the highest concentration of chitosan, the highest dosage of modified hydroxyapatite and sodium alginate, and the highest wetting pressure. Example 2 shows that even with lower dosage, it still maintains high antibacterial efficiency, proving that the formulation of this invention is reasonable and can achieve long-lasting antibacterial effect with low addition amount, balancing cost and performance.

[0038] II. Analysis of Absorption and Skin-Friendliness Results Absorption and Anti-backflow Performance: Examples 1-3 all showed absorption amounts ≥17.5g and backflow amounts ≤0.15g, significantly better than the comparative examples. This indicates that modified hydroxyapatite can improve the absorbency and conductivity of the skin-friendly surface layer. Combined with the hygroscopic effect of chitosan, it accelerates the flow of menstrual blood to the absorbent core, reduces surface residue, and lowers backflow. Comparative Example 1 showed a backflow amount as high as 0.87g, indicating poor absorbency and conductivity of the unmodified surface layer. Comparative Examples 2-5 showed significantly higher backflow amounts than the examples, demonstrating that the synergistic effect of modified hydroxyapatite and sodium alginate can optimize the surface structure and improve the anti-backflow effect.

[0039] The skin-friendly and low-irritation performance examples all had skin irritation scores ≤0.3, belonging to the non-irritating level, demonstrating excellent skin affinity. Comparative Example 1 scored 1.2, indicating that ordinary surface coatings are prone to friction and skin irritation; Comparative Examples 2-5 scored 0.5-0.8, indicating some irritation due to insufficient modification or inadequate infiltration. This shows that the natural skin affinity of chitosan, the soothing and moisturizing effect of sodium alginate, and the gentle regulating effect of glycolic acid and citric acid work synergistically to significantly reduce skin irritation, making it suitable for sensitive skin and achieving long-lasting skin affinity.

[0040] III. Summary of Overall Technical Results Chitosan permeation liquid system: With chitosan as the core antibacterial component, it is combined with modified hydroxyapatite and sodium alginate to form a synergistic system of "antibacterial-loading-slow release-skin-friendly", which solves the problems of easy loss of chitosan and short antibacterial effect.

[0041] High-pressure impregnation process: 10-20MPa high-pressure impregnation achieves deep penetration, allowing antibacterial components to bind inside the fiber rather than adhering to the surface, fundamentally improving the durability of antibacterial properties.

[0042] Multiple modifications and optimizations: Modified hydroxyapatite improves dispersibility and load-bearing capacity, while sodium alginate optimizes solubility and skin-friendliness. Together, they enhance the overall performance of sanitary napkins, including antibacterial properties, skin-friendliness, and anti-backflow properties.

[0043] Safe, environmentally friendly, and non-irritating: Made entirely with natural antibacterial ingredients, without chemical antibacterial agents, it is safe and non-irritating, suitable for sensitive skin, and meets consumers' needs for healthy and hygienic products.

[0044] Stable process and easy to mass-produce: The preparation process is simple and the parameters are controllable, making it suitable for large-scale industrial production. It can be widely used in disposable hygiene products such as sanitary napkins, panty liners, and period panties.

[0045] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A long-lasting, antibacterial, skin-friendly sanitary napkin, characterized in that, The components, from top to bottom, are: a skin-friendly surface layer, a flow-guiding layer, an absorbent core, a leak-proof bottom layer, and a release paper. The skin-friendly surface layer is treated with a chitosan permeation solution, with a permeation pressure of 10-20 MPa and a permeation time of 1 hour. The chitosan permeation solution is prepared by the following method: adding 20-25% modified hydroxyapatite and 8-12% sodium alginate to a 4-6% (w / w) chitosan solution, and stirring thoroughly to obtain the chitosan permeation solution. The modified hydroxyapatite is prepared by the following steps: S1: preheating hydroxyapatite at 55-60℃ for 1 hour to obtain preheated hydroxyapatite; S2: stirring and modifying the preheated hydroxyapatite and the modification solution at a weight ratio of 3:(5-7) with a stirring speed of 350-400 r / min for 1 hour; S3: after stirring, filtering and drying to obtain modified hydroxyapatite; wherein, the modification solution is prepared by fully mixing sodium silicate solution, silane coupling agent KH550 and nano calcium carbonate at a weight ratio of (5-8):(1-3):

2. The sodium alginate agent is prepared by the following method: a sodium alginate solution with a mass fraction of 5-8%, glycolic acid and citric acid are mixed thoroughly in a weight ratio of (5-8):4:(1-3) to prepare the sodium alginate agent.

2. The antibacterial, long-lasting, skin-friendly sanitary napkin according to claim 1, characterized in that, The skin-friendly surface layer is made of pure cotton non-woven fabric, spunlace non-woven fabric, or bamboo fiber non-woven fabric; the diversion layer is made of hot air non-woven fabric; the absorbent core is made of a composite core of superabsorbent polymer and wood pulp fiber; the leak-proof bottom layer is made of breathable PE film; and the release paper is made of glassine paper.

3. A method for preparing the antibacterial, long-lasting, skin-friendly sanitary napkin according to claim 1 or 2, characterized in that, The process includes the following steps: S100: Skin-friendly surface pretreatment: The skin-friendly surface is placed in a chitosan permeation solution and soaked for 1 hour under a pressure of 10-20 MPa. After removal, it is dried at 50-60℃ until the moisture content is ≤8% to obtain an antibacterial skin-friendly surface; S200: Layered composite: The skin-friendly surface, the diversion layer, the absorbent core, and the leak-proof bottom layer are stacked in sequence and formed by hot pressing; S300: Auxiliary processing: Three-dimensional protective barriers are set on both sides of the composite layer, and release paper is laminated to the bottom of the leak-proof bottom layer. After slitting and packaging, an antibacterial and durable skin-friendly sanitary napkin is obtained.

4. The method for preparing the antibacterial, long-lasting, skin-friendly sanitary napkin according to claim 3, characterized in that, In step S200, the hot pressing temperature is 110-130℃ and the hot pressing pressure is 0.3-0.5MPa.

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