A sanitary napkin for long-term slow release of hydrogen gas and a method for manufacturing the same

Abstract

The application provides a long-acting hydrogen slow-release sanitary napkin and a preparation method thereof, and relates to the technical field of sanitary products. The long-acting hydrogen slow-release sanitary napkin comprises a skin-friendly surface layer, a long-acting hydrogen slow-release functional layer, a flow guide layer, an absorbent core, an anti-seepage bottom film, a back adhesive layer and release paper, and the skin-friendly surface layer, the long-acting hydrogen slow-release functional layer, the flow guide layer, the absorbent core, the anti-seepage bottom film, the back adhesive layer and the release paper are sequentially stacked from top to bottom. The long-acting hydrogen slow-release functional layer is composed of a flexible carrier substrate loaded with long-acting hydrogen slow-release microcapsules. The application solves the problems of existing hydrogen functional sanitary products, such as easy hydrogen escape, poor storage stability, short slow-release time, uncontrollable hydrogen production, strong skin irritation and unreasonable structure design, while guaranteeing the biological safety of the product. On the premise of not affecting the basic absorption and anti-seepage performance of the sanitary napkin, the product is endowed with excellent antioxidant, anti-inflammatory, antibacterial and pain relief effects.

Description

Technical Field

[0001] This invention relates to the field of hygiene products technology, specifically to a sanitary napkin with long-lasting slow-release hydrogen and its preparation method. Background Technology

[0002] Sanitary napkins are essential hygiene products for women during menstruation. Their core functions are to absorb menstrual blood, prevent leakage, and ensure cleanliness and comfort during menstruation. With the upgrading of women's health care needs, ordinary sanitary napkins can no longer meet diverse care requirements. Sanitary napkins with functions such as antibacterial properties, odor removal, pain relief, and mucosal repair have become the mainstream direction of industry development. Currently, commercially available functional sanitary napkins mostly adopt the following technical routes: First, adding ingredients such as traditional Chinese medicine extracts and plant essential oils to achieve antibacterial and uterine warming effects. However, these ingredients are prone to oxidation and deterioration, have a short shelf life, and pose a risk of allergies. Some ingredients can also disrupt the vaginal microecological balance. Second, adding chemical antibacterial agents such as silver ions and quaternary ammonium salts. Although the antibacterial effect is significant, long-term use can easily lead to bacterial resistance and may also damage the vulvar mucosal barrier. Third, using a uterine warming design that generates heat through iron powder oxidation. This can only relieve menstrual cramps through physical heat application and cannot solve core problems such as menstrual inflammation and bacterial imbalance. Furthermore, there is a risk of skin burns due to excessively high local temperatures. Hydrogen is an endogenous gas molecule. Recent medical research has confirmed that hydrogen has selective antioxidant, potent anti-inflammatory, broad-spectrum antibacterial, analgesic, and repairing biological effects. It can selectively scavenge malignant reactive oxygen species such as hydroxyl free radicals in the body, inhibit the release of inflammatory factors, and reduce tissue oxidative damage. Moreover, hydrogen has a very small molecular weight, which can quickly penetrate the skin and mucous membranes to exert its effects. Its metabolic product is water, leaving no residue, toxicity, or side effects. It is a highly safe bioactive molecule and is very suitable for women's menstrual intimate care. However, the application of hydrogen in the field of hygiene products faces many technical bottlenecks. Hydrogen is difficult to store, its molecular radius is extremely small, making it very easy to diffuse and escape, and its safety is insufficient. Existing hydrogen production systems tend to generate strong alkaline substances after reaction, leading to excessively high local pH values, which can cause strong irritation to the delicate skin and mucous membranes of the vulva, and even cause allergies and burns, failing to meet the safety standards for intimate care products. Therefore, this invention develops a slow-release hydrogen sanitary napkin with good storage stability, controllable and long-lasting hydrogen production, high safety, and no impact on basic performance, thereby effectively solving the above-mentioned problems and difficulties. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a sanitary napkin with long-lasting hydrogen release and its preparation method. It solves the problems of existing hydrogen-functional sanitary products, such as easy hydrogen escape, poor storage stability, short release time, uncontrollable hydrogen production, strong skin irritation, and unreasonable structural design. This invention enables the sanitary napkin to be stably stored for more than 2 years under dry and sealed conditions, and to release hydrogen steadily and for a long time upon contact with physiological fluids, with a continuous hydrogen production time of ≥8 hours. Simultaneously, it ensures the product's biosafety and, without affecting the basic absorbency and leak-proof performance of the sanitary napkin, endows the product with excellent antioxidant, anti-inflammatory, antibacterial, and dysmenorrhea-relieving effects.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A sanitary napkin with long-lasting hydrogen release includes a skin-friendly surface layer, a long-lasting hydrogen-generating functional layer, a diversion layer, an absorbent core, a leak-proof bottom membrane, an adhesive layer, and a release paper. The skin-friendly surface layer, long-lasting hydrogen-generating functional layer, diversion layer, absorbent core, leak-proof bottom membrane, adhesive layer, and release paper are stacked sequentially from top to bottom. The long-lasting hydrogen-generating functional layer is composed of a flexible carrier substrate loaded with long-lasting hydrogen-generating microcapsules. The long-lasting hydrogen-generating microcapsules include a core material and a wall material. The core material is a modified hydrogen-generating composition, and the wall material is a composite controlled-release wall material. The modified hydrogen-producing composition of the core material includes modified magnesium hydride powder, pH buffer, corrosion inhibitor, and dispersant. The modified magnesium hydride powder comprises 40-60 parts by weight, the pH buffer 20-35 parts, the corrosion inhibitor 3-8 parts, and the dispersant 2-5 parts. The pH buffer is a citrate-sodium citrate buffer pair with a mass ratio of 1:2-1:4. The corrosion inhibitor is sodium lignosulfonate or sodium dodecylbenzenesulfonate. The dispersant is fumed silica. The modified magnesium hydride powder is a silane coupling agent-modified hydrophobically. The modification method involves placing the magnesium hydride powder in anhydrous ethanol, adding 2%-5% (by weight) of the silane coupling agent KH-570 under nitrogen protection, stirring at a constant temperature of 40-50°C for 2-4 hours, filtering, and vacuum drying to obtain modified magnesium hydride powder with a particle size of 10-50 μm.

[0005] Furthermore, the composite controlled-release wall comprises a film-forming substrate, a plasticizer, and an emulsifier. The film-forming substrate, plasticizer, and emulsifier are 30-50 parts by weight, 2-5 parts by weight, and 1-3 parts by weight. The film-forming substrate is a mixture of chitosan and ethyl cellulose in a mass ratio of 1:2-1:4. The plasticizer is glycerol. The emulsifier is Tween-80. The mass ratio of the core material to the wall material of the long-acting sustained-release hydrogen-producing microcapsule is 1:1-1:3.

[0006] Furthermore, the particle size of the long-acting sustained-release hydrogen-producing microcapsules is 50-200μm, the flexible carrier substrate is hot-air nonwoven fabric or dust-free paper with a basis weight of 20-30g / ㎡, and the loading amount of the long-acting sustained-release hydrogen-producing microcapsules on the flexible carrier substrate is 5-15g / ㎡.

[0007] Furthermore, the skin-friendly surface layer is made of pure cotton non-woven fabric or ES hydrophilic non-woven fabric with a basis weight of 15-25 g / m²; the flow-guiding layer is made of hot air flow-guiding non-woven fabric with a basis weight of 25-35 g / m²; the absorbent core is made of superabsorbent polymer and dust-free paper composite with a basis weight of 80-120 g / m²; and the impermeable bottom membrane is a PE breathable membrane with a basis weight of 15-25 g / m².

[0008] A method for preparing a sanitary napkin with long-lasting, sustained-release hydrogen gas, characterized in that the method includes the following steps: Step 1: Preparation of modified hydrogen-producing composition; Modified magnesium hydride powder was prepared by mixing the modified magnesium hydride powder, pH buffer, corrosion inhibitor, and dispersant at high speed under nitrogen protection according to the specified ratio to obtain a modified hydrogen-producing composition. Step 2: Preparation of long-acting sustained-release hydrogen-producing microcapsules; The composite controlled-release wall material was dissolved in a solvent to prepare a wall material solution. A modified hydrogen-generating composition was added to the wall material solution, and the mixture was dispersed and homogenized at high speed to obtain a suspension. The suspension was then spray-dried to prepare long-acting sustained-release hydrogen-generating microcapsules. Step 3: Preparation of the long-lasting sustained-release hydrogen production functional layer; Long-acting sustained-release hydrogen-producing microcapsules were mixed with aqueous adhesive and deionized water to prepare a spray suspension. The spray suspension was uniformly sprayed onto the surface of a flexible carrier substrate and dried at low temperature to obtain a long-acting sustained-release hydrogen-producing functional layer. Step 4: Sanitary napkin lamination and molding; The skin-friendly surface layer, long-lasting hydrogen-producing functional layer, flow-guiding layer, absorbent core, and impermeable bottom membrane are layered and laminated in sequence. Adhesive is applied to the back of the impermeable bottom membrane, release paper is attached, and the product is obtained through slitting, folding, sterilization, and packaging.

[0009] Further, in step 2, the solvent for preparing the long-acting sustained-release hydrogen-producing microcapsules is an 80% (v / v) aqueous ethanol solution; the solid content of the wall material adhesive is 8%–15%; the high-speed dispersion homogenization speed is 12000 r / min, and the time is 15–20 min. The inlet air temperature of the spray drying is 120–140℃, the outlet air temperature is 60–70℃, and the feed rate is 5–10 mL / min.

[0010] Furthermore, in the preparation of the long-acting sustained-release hydrogen-producing functional layer in step 3, the sprayed suspension comprises, by weight: 10-20 parts of long-acting sustained-release hydrogen-producing microcapsules, 3-8 parts of waterborne polyurethane adhesive, and 72-87 parts of deionized water; the low-temperature drying temperature is 40-50℃, and the moisture content of the substrate after drying is ≤3%.

[0011] Furthermore, in step S4, the sanitary napkin composite molding process, the layers are bonded together by hot melt adhesive spraying, with a hot melt adhesive coating amount of 1-3 g / ㎡, and the sterilization method is ethylene oxide sterilization.

[0012] This invention provides a sanitary napkin with long-lasting sustained hydrogen release and its preparation method. It has the following beneficial effects: 1. This invention provides a sanitary napkin with long-lasting slow-release hydrogen and its preparation method. Through a dual protection technology of hydrophobic modification of magnesium hydride surface and microcapsule encapsulation, a hydrophobic isolation layer is constructed on the surface of modified magnesium hydride powder. At the same time, a secondary sealing protection is formed by composite controlled-release wall material, which can effectively isolate water vapor in the air and prevent premature hydrogen production reaction during storage. This completely solves the pain points of existing products such as easy hydrogen escape and short shelf life, meets the storage and commercial application requirements of sanitary products, and achieves precise control of hydrogen production rate through the dual slow-release technology of water-permeable wall material and reaction system regulation, which fully covers the normal use time of sanitary napkins and solves the problems of excessively rapid hydrogen production and short slow-release time of existing products.

[0013] 2. This invention provides a sanitary napkin with long-lasting slow-release hydrogen and its preparation method. The byproducts of the core hydrogen production reaction are magnesium hydroxide and magnesium citrate, both of which are non-toxic, harmless, and biocompatible materials with no residue and no carcinogenic or teratogenic risks. Furthermore, the long-lasting slow-release hydrogen production functional layer is innovatively set independently between the skin-friendly surface layer and the diversion layer, which fully preserves the basic properties of the sanitary napkin, such as absorption, seepage prevention, and side leakage prevention, and solves the problem of unreasonable structure and inability to balance efficacy and basic performance in existing products.

[0014] 3. This invention provides a sanitary napkin with long-lasting sustained-release hydrogen gas and its preparation method. Through the long-lasting sustained-release hydrogen gas, the sanitary napkin is endowed with multiple care effects. Hydrogen gas can selectively remove excess malignant free radicals in the body during menstruation, inhibit the release of prostaglandins and inflammatory factors, effectively relieve menstrual pain symptoms, inhibit the growth of harmful bacteria during menstruation such as Escherichia coli, Staphylococcus aureus, and Candida albicans, effectively improve problems such as vulvar itching, odor, and redness during menstruation, repair damaged vulvar mucosal barrier, reduce skin sensitivity problems during menstruation, and has no side effects. It can be used safely for a long time, comprehensively upgrading the women's menstrual care experience. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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 of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0016] Example 1: This invention provides a sanitary napkin with long-lasting sustained-release hydrogen gas, comprising a skin-friendly surface layer, a long-lasting sustained-release hydrogen-generating functional layer, a diversion layer, an absorbent core, a leak-proof bottom membrane, an adhesive backing layer, and a release paper. The skin-friendly surface layer, long-lasting sustained-release hydrogen-generating functional layer, diversion layer, absorbent core, leak-proof bottom membrane, adhesive backing layer, and release paper are stacked sequentially from top to bottom. The long-lasting sustained-release hydrogen-generating functional layer is composed of a flexible carrier substrate loaded with long-lasting sustained-release hydrogen-generating microcapsules. The long-lasting sustained-release hydrogen-generating microcapsules include a core material and a wall material. The core material is a modified hydrogen-generating composition, and the wall material is a composite controlled-release wall material. The modified hydrogen-producing composition of the core material includes modified magnesium hydride powder, pH buffer, corrosion inhibitor, and dispersant. The modified magnesium hydride powder comprises 40-60 parts by weight, the pH buffer 20-35 parts, the corrosion inhibitor 3-8 parts, and the dispersant 2-5 parts. The pH buffer is a citrate-sodium citrate buffer pair with a mass ratio of 1:2-1:4. The corrosion inhibitor is sodium lignosulfonate or sodium dodecylbenzenesulfonate. The dispersant is fumed silica. The modified magnesium hydride powder is a silane coupling agent-modified hydrophobic magnesium hydride powder. The modification method involves placing the magnesium hydride powder in anhydrous ethanol, adding 2%-5% (by weight) of the silane coupling agent KH-570 under nitrogen protection, stirring at a constant temperature of 40-50℃ for 2-4 hours, filtering, and vacuum drying to obtain modified magnesium hydride powder with a particle size of 10-50 μm. The composite controlled-release wall comprises a film-forming substrate, a plasticizer, and an emulsifier. The film-forming substrate comprises 30-50 parts by weight, the plasticizer 2-5 parts, and the emulsifier 1-3 parts. The film-forming substrate is a mixture of chitosan and ethyl cellulose in a mass ratio of 1:2-1:4. The plasticizer is glycerol; the emulsifier is Tween-80. The mass ratio of the core material to the wall material of the long-acting sustained-release hydrogen-producing microcapsules is 1:1-1:3. The particle size of the long-acting sustained-release hydrogen-producing microcapsules is 50-200 μm. The flexible carrier substrate is... The substrate consists of a hot-air nonwoven fabric or dust-free paper with a basis weight of 20-30 g / m², a long-acting sustained-release hydrogen-producing microcapsules with a loading of 5-15 g / m² on a flexible carrier substrate, a skin-friendly surface layer of pure cotton nonwoven fabric or ES hydrophilic nonwoven fabric with a basis weight of 15-25 g / m², a flow-guiding layer of hot-air flow-guiding nonwoven fabric with a basis weight of 25-35 g / m², an absorbent core composed of superabsorbent polymer and dust-free paper with a basis weight of 80-120 g / m², and a waterproof bottom membrane of PE breathable membrane with a basis weight of 15-25 g / m².

[0017] Example 2: This invention provides a method for preparing a sanitary napkin with long-lasting sustained hydrogen release, the method comprising the following steps: Step 1: Preparation of modified hydrogen-producing composition; Modified magnesium hydride powder was prepared by mixing the modified magnesium hydride powder, pH buffer, corrosion inhibitor, and dispersant at high speed under nitrogen protection according to the specified ratio to obtain a modified hydrogen-producing composition. Step 2: Preparation of long-acting sustained-release hydrogen-producing microcapsules; The composite controlled-release wall material was dissolved in a solvent to prepare a wall material solution. A modified hydrogen-generating composition was added to the wall material solution, and the mixture was dispersed and homogenized at high speed to obtain a suspension. The suspension was then spray-dried to prepare long-acting sustained-release hydrogen-generating microcapsules. Step 3: Preparation of the long-lasting sustained-release hydrogen production functional layer; Long-acting sustained-release hydrogen-producing microcapsules were mixed with aqueous adhesive and deionized water to prepare a spray suspension. The spray suspension was uniformly sprayed onto the surface of a flexible carrier substrate and dried at low temperature to obtain a long-acting sustained-release hydrogen-producing functional layer. Step 4: Sanitary napkin lamination and molding; The skin-friendly surface layer, long-lasting hydrogen-producing functional layer, flow-guiding layer, absorbent core, and impermeable bottom membrane are layered and laminated in sequence. Adhesive is applied to the back of the impermeable bottom membrane, release paper is attached, and the finished product is obtained through slitting, folding, sterilization, and packaging. The solvent for preparing the long-acting sustained-release hydrogen-producing microcapsules in step 2 is an 80% (v / v) aqueous ethanol solution; the solid content of the wall material adhesive is 8%–15%; the high-speed dispersion homogenization speed is 12000 r / min, and the time is 15–20 min. The inlet air temperature of the spray drying is 120–140℃, the outlet air temperature is 60–70℃, and the feed rate is 5–10 mL / min. In the preparation of the long-acting sustained-release hydrogen-producing functional layer in step 3, the sprayed suspension, by weight, includes: 10–20 parts of long-acting sustained-release hydrogen-producing microcapsules, 3–8 parts of waterborne polyurethane adhesive, and 72–87 parts of deionized water; the low-temperature drying temperature is 40–50℃, and the moisture content of the substrate after drying is ≤3%. In the sanitary napkin composite molding in step S4, the layers are composited by hot melt adhesive spraying, the hot melt adhesive coating amount is 1–3 g / m², and the sterilization method is ethylene oxide sterilization.

[0018] Example 3: This embodiment provides a sanitary napkin with long-lasting hydrogen release, comprising, from top to bottom, a skin-friendly surface layer, a long-lasting hydrogen-generating functional layer, a diversion layer, an absorbent core, a leak-proof bottom membrane, an adhesive layer, and a release paper. The skin-friendly surface layer is made of 20g / m² ES hydrophilic nonwoven fabric; the diversion layer is made of 30g / m² hot-air diversion nonwoven fabric; the absorbent core is a composite of superabsorbent polymer and dust-free paper, with a weight of 100g / m²; and the leak-proof bottom membrane is a 20g / m² PE breathable membrane. The hydrogen functional layer is composed of hot-air nonwoven fabric loaded with long-acting sustained-release hydrogen-producing microcapsules. The hot-air nonwoven fabric has a basis weight of 25 g / m² and a microcapsule loading of 10 g / m². The core material of the long-acting sustained-release hydrogen-producing microcapsules is a modified hydrogen-producing composition, and the wall material is a composite controlled-release wall material with a core-to-wall mass ratio of 1:2. The modified hydrogen-producing composition, by weight, includes: 50 parts of modified magnesium hydride powder, 28 parts of citric acid-sodium citrate buffer pair (citric acid to sodium citrate mass ratio 1:3), 5 parts of sodium lignosulfonate, and 2 parts of fumed silica. Preparation method of modified magnesium hydride powder: magnesium hydride powder is placed in anhydrous ethanol, and 3% of the mass of magnesium hydride powder silane coupling agent KH-570 is added under nitrogen protection. The mixture is stirred at 45℃ for 3 hours, filtered, and the filter cake is washed three times with anhydrous ethanol and dried under vacuum at 35℃ for 7 hours to obtain modified magnesium hydride powder with a particle size of 20-40μm. The composite controlled-release wall material, by weight, includes 40 parts of film-forming substrate, chitosan and ethyl cellulose in a mass ratio of 1:3, 3 parts of glycerol, and 2 parts of Tween-80. The preparation method of the long-lasting hydrogen-releasing sanitary napkin in this embodiment includes the following detailed steps: Preparation of S1 modified hydrogen production composition: Modified magnesium hydride powder was prepared according to the above method. Each raw material was weighed according to the weight ratio. In a closed environment under nitrogen protection, the mixture was mixed at a high speed of 4000 r / min for 12 min. After uniform mixing, the modified hydrogen production composition was obtained and stored in a sealed container for later use. Preparation of S2 long-acting sustained-release hydrogen-generating microcapsules: The film-forming substrate, glycerol, and Tween-80 were added to an 80% (v / v) aqueous ethanol solution according to the specified ratio. The solution was stirred at 45°C until completely dissolved to prepare a wall material solution with a solid content of 10%. The modified hydrogen-generating composition was added to the wall material solution and pre-dispersed at 3000 r / min for 5 min, and then homogenized at a high speed of 10000 r / min for 15 min to obtain a uniform suspension. The suspension was fed into a spray dryer with an inlet air temperature of 130°C, an outlet air temperature of 65°C, and a feed rate of 8 mL / min. After spray drying, the powder was collected to obtain long-acting sustained-release hydrogen-generating microcapsules with a particle size of 80-150 μm, which were then stored in a nitrogen-sealed container for later use. Preparation of S3 long-lasting sustained-release hydrogen production functional layer: Weigh 15 parts of long-lasting sustained-release hydrogen production microcapsules, 5 parts of water-based polyurethane adhesive, and 80 parts of deionized water according to the weight ratio. Stir at 2500 r / min for 12 min at room temperature to obtain a spray suspension. Use a precision spraying device to uniformly spray the suspension onto the surface of hot air nonwoven fabric, dry at a low temperature of 45℃, and control the moisture content of the substrate to ≤3% to obtain the long-lasting sustained-release hydrogen production functional layer, which is then cut for later use. S4 Sanitary Napkin Composite Molding: Using a sanitary napkin production line, the layers are stacked sequentially and laminated with hot melt adhesive sprayed between each layer. The hot melt adhesive coating amount is 2g / ㎡, and the lamination pressure is 0.25MPa. Adhesive is coated on the back of the leak-proof bottom film, and release paper is attached. After slitting and folding, the product is sterilized with ethylene oxide, sealed and packaged to obtain the finished product.

[0019] The following points should be noted in this article: 1. The embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures may refer to general designs.

[0020] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0021] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A sanitary napkin with long-lasting hydrogen release, comprising a skin-friendly surface layer, a long-lasting hydrogen-generating functional layer, a diversion layer, an absorbent core, a leak-proof bottom film, an adhesive backing layer, and a release paper, characterized in that: The skin-friendly surface layer, long-lasting sustained-release hydrogen-generating functional layer, flow-guiding layer, absorbent core, impermeable bottom membrane, adhesive layer, and release paper are stacked sequentially from top to bottom. The long-lasting sustained-release hydrogen-generating functional layer is composed of a flexible carrier substrate loaded with long-lasting sustained-release hydrogen-generating microcapsules. The long-lasting sustained-release hydrogen-generating microcapsules include a core material and a wall material. The core material is a modified hydrogen-generating composition, and the wall material is a composite controlled-release wall material. The modified hydrogen-producing composition of the core material includes modified magnesium hydride powder, pH buffer, corrosion inhibitor, and dispersant. The modified magnesium hydride powder comprises 40-60 parts by weight, the pH buffer 20-35 parts, the corrosion inhibitor 3-8 parts, and the dispersant 2-5 parts. The pH buffer is a citrate-sodium citrate buffer pair with a mass ratio of 1:2-1:

4. The corrosion inhibitor is sodium lignosulfonate or sodium dodecylbenzenesulfonate. The dispersant is fumed silica. The modified magnesium hydride powder is a silane coupling agent-modified hydrophobically. The modification method involves placing the magnesium hydride powder in anhydrous ethanol, adding 2%-5% (by weight) of the silane coupling agent KH-570 under nitrogen protection, stirring at a constant temperature of 40-50°C for 2-4 hours, filtering, and vacuum drying to obtain modified magnesium hydride powder with a particle size of 10-50 μm.

2. The sanitary napkin with long-lasting hydrogen release and its preparation method according to claim 1, characterized in that: The composite controlled-release wall comprises a film-forming substrate, a plasticizer, and an emulsifier. The film-forming substrate, plasticizer, and emulsifier are 30-50 parts by weight, 2-5 parts by weight, and 1-3 parts by weight. The film-forming substrate is a mixture of chitosan and ethyl cellulose in a mass ratio of 1:2-1:

4. The plasticizer is glycerol. The emulsifier is Tween-80. The mass ratio of the core material to the wall material of the long-acting sustained-release hydrogen-producing microcapsule is 1:1-1:

3.

3. The sanitary napkin with long-lasting slow-release hydrogen gas according to claim 1 and its preparation method, characterized in that: The long-acting sustained-release hydrogen-producing microcapsules have a particle size of 50-200 μm, the flexible carrier substrate is hot-air nonwoven fabric or dust-free paper with a basis weight of 20-30 g / m², and the loading amount of the long-acting sustained-release hydrogen-producing microcapsules on the flexible carrier substrate is 5-15 g / m².

4. The sanitary napkin with long-lasting slow-release hydrogen gas according to claim 1 and its preparation method, characterized in that: The skin-friendly surface layer is made of pure cotton non-woven fabric or ES hydrophilic non-woven fabric with a basis weight of 15-25g / ㎡; the flow-guiding layer is made of hot air flow-guiding non-woven fabric with a basis weight of 25-35g / ㎡; the absorbent core is made of superabsorbent polymer and dust-free paper composite with a basis weight of 80-120g / ㎡; and the impermeable bottom membrane is made of PE breathable membrane with a basis weight of 15-25g / ㎡.

5. A sanitary napkin with long-lasting slow-release hydrogen gas and its preparation method, characterized in that: The method includes the following steps: Step 1: Preparation of modified hydrogen-producing composition; Modified magnesium hydride powder was prepared by mixing the modified magnesium hydride powder, pH buffer, corrosion inhibitor, and dispersant at high speed under nitrogen protection according to the specified ratio to obtain a modified hydrogen-producing composition. Step 2: Preparation of long-acting sustained-release hydrogen-producing microcapsules; The composite controlled-release wall material was dissolved in a solvent to prepare a wall material solution. A modified hydrogen-generating composition was added to the wall material solution, and the mixture was dispersed and homogenized at high speed to obtain a suspension. The suspension was then spray-dried to prepare long-acting sustained-release hydrogen-generating microcapsules. Step 3: Preparation of the long-lasting sustained-release hydrogen production functional layer; Long-acting sustained-release hydrogen-producing microcapsules were mixed with aqueous adhesive and deionized water to prepare a spray suspension. The spray suspension was uniformly sprayed onto the surface of a flexible carrier substrate and dried at low temperature to obtain a long-acting sustained-release hydrogen-producing functional layer. Step 4: Sanitary napkin lamination and molding; The skin-friendly surface layer, long-lasting hydrogen-producing functional layer, flow-guiding layer, absorbent core, and impermeable bottom membrane are layered and laminated in sequence. Adhesive is applied to the back of the impermeable bottom membrane, release paper is attached, and the product is obtained through slitting, folding, sterilization, and packaging.

6. The sanitary napkin with long-lasting slow-release hydrogen gas according to claim 5 and its preparation method, characterized in that: The solvent for preparing the long-acting sustained-release hydrogen-producing microcapsules in step 2 is an 80% (v / v) aqueous ethanol solution; the solid content of the wall material adhesive is 8%–15%; the high-speed dispersion homogenization speed is 12000 r / min, and the time is 15–20 min. The inlet air temperature of the spray drying is 120–140℃, the outlet air temperature is 60–70℃, and the feed rate is 5–10 mL / min.

7. The sanitary napkin with long-lasting slow-release hydrogen gas according to claim 5 and its preparation method, characterized in that: In step 3, the preparation of the long-acting sustained-release hydrogen-producing functional layer, the sprayed suspension, by weight, includes 10-20 parts of long-acting sustained-release hydrogen-producing microcapsules, 3-8 parts of waterborne polyurethane adhesive, and 72-87 parts of deionized water; the low-temperature drying temperature is 40-50℃, and the moisture content of the substrate after drying is ≤3%.

8. The method for preparing a sanitary napkin with long-lasting hydrogen release according to claim 5, characterized in that: In step S4, the sanitary napkin composite molding process, the layers are bonded together by hot melt adhesive spraying, with a hot melt adhesive coating amount of 1-3 g / m², and sterilization is performed using ethylene oxide sterilization.