Alginate fiber sanitary towel and preparation method thereof

Abstract

The invention provides an alginate fiber sanitary towel and a preparation method thereof, and belongs to the technical field of nursing materials. Through the directional water-repellent design of the double-sided reverse osmosis prevention functional layer and in combination with the three-dimensional leakage-proof partition edge structure, the risks of liquid back seepage and side leakage are remarkably reduced, and the use dryness and reliability are improved; the natural antibacterial effect of the alginate fibers is utilized, efficient peculiar smell control is achieved, irritation of traditional chemical bacteriostatic agents to the skin is avoided, and biological safety is guaranteed; the core material adopts alginate fiber renewable resources, the characteristics of high water absorption and degradability of the alginate fiber absorber are combined, the environmental protection sustainability of the product is enhanced, the common problems of reverse osmosis, side leakage, dependence on chemical addition and the like of the sanitary towel are solved, meanwhile, the unification of the protection performance, the health attribute and the sustainability is achieved through material and structure innovation, and the sanitary towel is suitable for being used for sanitary napkins. And a technical normal form capable of being flexibly expanded is provided for the industry.

Description

Technical Field

[0001] This invention relates to the field of nursing care products technology, and in particular to a seaweed fiber sanitary napkin and its preparation method. Background Technology

[0002] Sanitary napkins, as a basic product for women's menstrual care, have the core function of quickly absorbing and locking in bodily fluids, keeping the skin surface dry, and preventing side leakage and odor. Traditional sanitary napkins typically use a multi-layered composite structure, including, from top to bottom, a permeable layer, a diversion layer, an absorbent core, an anti-backflow layer, and a waterproof bottom membrane. The top layer, which comes into direct contact with the skin, needs to be skin-friendly and have rapid absorption capabilities; the absorbent core is responsible for the main liquid absorption function and is often made of a mixture of wood pulp fibers and superabsorbent polymer (SAP); the bottom layer needs to balance breathability and leak-proof safety.

[0003] Despite continuous product iterations, several common technical bottlenecks remain: Liquid backflow issues: Some products are prone to liquid backflow under pressure, leading to skin dampness and discomfort, and potentially causing allergies with long-term use. This is mainly due to insufficient anti-backflow layer design or limited water-locking capacity of the core. Especially at night or in high-flow scenarios, liquid easily seeps from the side edges, affecting reliability. Existing leak-proof structures often rely on widened wings or thickened side panels, but this may sacrifice wearing comfort. To inhibit bacterial growth and odor, most products require the addition of chlorine bleach or synthetic antibacterial agents (such as triclosan), raising concerns about biosafety and potentially disrupting the skin's microecological balance. The surface layer widely uses petroleum-based nonwoven fabric, and the core relies on non-renewable wood pulp resources, conflicting with green consumption trends.

[0004] In recent years, the industry has attempted to introduce natural fibers (such as cotton and bamboo fiber) to replace synthetic materials, but this has faced problems such as poor adaptability to processing techniques and limited functionality. For example, natural antibacterial components are difficult to maintain their activity in high-temperature composite processes due to their heat sensitivity; uneven distribution can easily occur during fiber blending, leading to fluctuations in leak-proof performance. Therefore, there is an urgent need to develop a sanitary napkin structure and preparation method that combines high-efficiency leak prevention, natural antibacterial properties, and the application of environmentally friendly materials, thereby improving the user experience while responding to health-conscious consumer demands. Summary of the Invention

[0005] The purpose of this invention is to provide a seaweed fiber sanitary napkin and its preparation method, which can take into account the application of highly effective leak prevention, natural antibacterial properties and environmentally friendly materials.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a sanitary napkin, the overall structure of which, from top to bottom, consists of a surface layer, an upper anti-reverse osmosis functional layer, an absorbent core layer, a lower anti-reverse osmosis functional layer, a bottom film, and anti-leakage barriers located on both sides; each layer is tightly connected by hot-pressing composite, and the anti-leakage barriers are in an arc-shaped convex state to form a surrounding anti-leakage barrier; Both the upper and lower anti-reverse osmosis functional layers are non-woven fabrics, which are coated with a water-repellent finishing agent on one side to form a water-repellent and hydrophilic property on the other. The nonwoven fabric is made by mixing seaweed fiber and cotton fiber in a mass ratio of 0.1 to 100:1; The upper anti-reverse osmosis functional layer has its water-repellent surface facing upwards and its hydrophilic surface facing downwards, while the lower anti-reverse osmosis functional layer has its water-repellent surface facing downwards and its hydrophilic surface facing upwards. The absorbent core layer contains seaweed fiber absorbers.

[0007] Preferably, the surface layer has a basis weight of 10~90g / m². 2 Seaweed fiber nonwoven fabric.

[0008] Preferably, the water-repellent finishing agent comprises the following components in parts by weight: 8-18 parts of waterborne polyurethane, 4-10 parts of waterborne carnauba wax emulsion, 2-6 parts of polydimethylsiloxane PEG-10-15 crosslinked polymer, and 10-100 parts of deionized water.

[0009] The preparation method of the seaweed fiber absorbent includes the following steps: Using seaweed fiber as raw material, a cotton-like paper is made by airflow forming at a wind speed of 10~18m / s, hot pressing and curing at a temperature of 100~130℃ and a pressure of 0.1~0.4MPa; the thickness of the cotton-like paper is 0.1~0.4mm, and the seaweed fiber absorbent is a highly absorbent seaweed fiber copolymer.

[0010] Preferably, the bottom film is a breathable PE film with a thickness of 0.008~0.025mm.

[0011] Preferably, the anti-leakage partition is a non-woven fabric three-dimensional structure with a width of 5~15mm and a height of 2~6mm.

[0012] The present invention also provides a method for preparing the above-mentioned sanitary napkin, comprising the following steps: (a) Raw material pretreatment: treating seaweed fiber, cotton fiber, cotton-like paper, seaweed fiber absorbent, water-repellent finishing agent, breathable PE bottom film and seaweed fiber non-woven fabric surface layer; (b) Fabrication of the anti-reverse osmosis functional layer; (c) Fabrication of the absorbent core layer; (d) Topcoat and basecoat treatment; (e) Multi-layer composite and anti-leakage molding; (f) Post-processing.

[0013] Preferably, the pretreatment of seaweed fibers in step (a) includes: Cleaning: Water temperature 25~40℃, time 4~10 minutes; Crushing: Rotation speed 1200~1800r / min, crush to particle size ≤10mm; Alkaline extraction: NaOH solution mass fraction 1~5%, temperature 75~90℃, constant temperature extraction for 1.5~3h; Bleaching: Hydrogen peroxide mass fraction 0.5~3%, pH value 8~11, temperature 50~70℃ for 20-40 min; Drying: Hot air temperature 55~75℃, so that the moisture content is controlled at 5~12%.

[0014] Preferably, step (b) specifically includes: Seaweed fiber and cotton fiber are mixed at a mass ratio of 0.1 to 100:1, and then combed to form a single fiber web at a combing speed of 10 to 25 m / min and a web thickness of 0.2 to 0.6 mm. The mesh is laid in 3 to 6 layers at a speed of 10 to 25 m / min, with a total thickness of 0.8 to 1.5 mm. Hot air bonding: temperature 120~140℃, wind speed 8~18m / s, time 25~50s, to form a non-woven fabric substrate; Apply water-repellent finishing agent to one side, with a spraying amount of 6~12g / m². 2 Spraying pressure: 0.2~0.5MPa; Drying and curing: Temperature 70~100℃, time 1~5min.

[0015] Preferably, step (c) specifically includes: Cotton-like paper is made from seaweed fiber as raw material, formed by airflow at a wind speed of 10~18m / s, hot-pressed and cured at a temperature of 100~130℃ and a pressure of 0.1~0.4MPa; Production of seaweed fiber absorbent: Using seaweed fiber as raw material, it is formed into a net by airflow at a wind speed of 10~18m / s, hot-pressed and cured at a temperature of 100~130℃ and a pressure of 0.1~0.4MPa to make a cotton-like paper as the absorbent, with a dosage of 10~25g / m³. 2 Particle size: 0.05~0.4mm; Compacted with a light pressure roller at a pressure of 0.05~0.3MPa; Step (d) specifically includes: Surface treatment: Perforate the seaweed fiber nonwoven fabric with ventilation holes; Bottom film treatment: The unwinding tension of the breathable PE bottom film is controlled at 3-10N; Step (e) specifically includes: The layers are stacked in the following order: surface layer → upper anti-reverse osmosis functional layer → absorbent core layer → lower anti-reverse osmosis functional layer → bottom membrane. Hot pressing composite: temperature 65-85℃, pressure 0.2-0.5MPa, composite speed 10-25m / min; Non-woven fabric leak-proof barriers are added to both sides of the composite layer, and a three-dimensional barrier is formed by ultrasonic sealing with a sealing frequency of 18-28kHz.

[0016] The technical effects and advantages of this invention are as follows: This invention significantly reduces the risk of liquid backflow and side leakage through a directional water-repellent design with a double-sided anti-reverse osmosis functional layer, combined with a three-dimensional leak-proof edge structure, thereby improving dryness and reliability. It utilizes the natural antibacterial properties of seaweed fiber to achieve efficient odor control, avoiding skin irritation from traditional chemical antibacterial agents and ensuring biocompatibility. The core material uses renewable resources such as seaweed fiber, combined with the high absorbency and biodegradability of the seaweed fiber absorbent, enhancing the product's environmental sustainability.

[0017] This invention provides consumers with a sanitary napkin option that combines high protection, health and safety, and eco-friendliness, especially suitable for users with sensitive skin and those who prefer natural products. It boasts strong scalability: the anti-backflow layer can be adapted to contain fluorinated water-repellent agents to extend its lifespan; the absorbent core can balance absorbency and environmental requirements by adjusting the proportion of seaweed fibers; and the leak-proof side panels use elastic materials to improve body fit, meeting diverse market demands. While addressing common problems in sanitary napkins such as backflow, side leakage, dependence on chemical additives, lack of antibacterial properties, and biodegradability, this invention achieves a unity of protective performance, antibacterial and odor-eliminating properties, health attributes, and sustainability through material and structural innovation, providing the industry with a flexibly scalable technological paradigm. Attached Figure Description

[0018] Figure 1 Photograph of the core layer before it absorbs water; Figure 2 Photograph of the core layer after it has absorbed water; Figure 3 Test report 1 for the seaweed fiber material used in this invention; Figure 4 Test report 2 for the seaweed fiber material used in this invention; Figure 5 Test report 3 for the seaweed fiber material used in this invention. Detailed Implementation

[0019] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0020] Example 1 The overall structure of a sanitary napkin, from top to bottom, is as follows: Surface layer (using 22.5g / m²) 2 The seaweed fiber nonwoven fabric has a certain degree of antibacterial properties and features a diameter of 0.65mm and a pore density of 35 pores / cm². 2 (vent holes) The upper anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 45g / m²) 2 Apply a water-repellent finishing agent to one side (mass fraction: 12.5% ​​waterborne polyurethane, 6.5% waterborne carnauba wax emulsion, 4% polydimethylsiloxane PEG-10-15 crosslinked polymer, balance deionized water), with the water-repellent side facing up and the hydrophilic side facing down, and a contact angle ≥130°. Absorbent core layer (including cotton-like paper (0.25mm thick), seaweed fiber absorbent (sodium alginate copolymer), antibacterial rate: ≥90% against Escherichia coli and Staphylococcus aureus, with a sustained antibacterial time of ≥8h) The lower anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 45g / m²) 2 A single-sided spray coating of water-repellent finishing agent (mass fraction: 12.5% ​​waterborne polyurethane, 6.5% waterborne carnauba wax emulsion, 4% polydimethylsiloxane PEG-10-15 crosslinked polymer, balance deionized water) is applied with the water-repellent side facing down and the hydrophilic side facing up, with a contact angle ≥130°. Bottom film (breathable PE film, 0.015mm thick) And the side leakage prevention partitions located on both sides (non-woven fabric three-dimensional structure, 9mm wide and 4mm high).

[0021] Each layer is tightly connected by hot-pressing composite, and the anti-leakage partition is in an arc-shaped protrusion, forming a surrounding anti-leakage barrier.

[0022] The production process includes raw material pretreatment, anti-reverse osmosis functional layer fabrication, absorbent core layer fabrication, surface and bottom membrane treatment, multi-layer composite and anti-side leakage molding, post-processing and quality inspection.

[0023] In the raw material pretreatment stage, the core raw materials include seaweed fiber with a length of 4mm and a fineness of 1.35dtex, cotton fiber with a length of 3mm and a fineness of 1.1dtex, cotton-like paper, seaweed fiber absorbent, water-repellent finishing agent, breathable PE bottom film, and seaweed fiber nonwoven fabric surface layer.

[0024] The seaweed raw materials (brown / red algae) were washed (water temperature 32.5℃, washing time 6.5 min), crushed (speed 1500 r / min, crushed to particle size ≤5 mm), extracted using an alkaline method (NaOH solution mass fraction 2.5%, constant temperature extraction at 82.5℃ for 2 h, to separate seaweed fibers), bleached (hydrogen peroxide mass fraction 1.5%, pH value 9.5, treated at 60℃ for 30 min), and dried (hot air temperature 65℃, moisture content controlled at 9%). The test report for the seaweed fiber material used in this invention is as follows: Figures 3-4 As shown.

[0025] Cotton fibers are opened using a fiber opener (800 rpm) to remove knots and impurities. Then, they are thoroughly mixed with seaweed fibers in a blender at a 1:9 mass ratio (mixing time 12.5 min, uniformity ≥95%). For the anti-reverse osmosis functional layer, the mixed fibers are carded into a single-fiber web (carding speed 17.5 m / min, web thickness 0.4 mm). After being layered by a web-laying machine (4 layers, web-laying speed 17.5 m / min, total thickness 1.1 mm), they are bonded using a hot air bonding machine (hot air temperature 130℃, air velocity 12.5 m / s, bonding time 35 s) to form a nonwoven fabric base (45 g / m²). 2 Subsequently, a single-sided spraying machine was used to evenly spray the water-repellent finishing agent onto one side of the nonwoven fabric (spraying amount 9g / m²). 2 The coating is applied at a pressure of 0.35 MPa and then dried in an oven at 85°C for 2.5 minutes to form a functional layer with a water-repellent surface contact angle of ≥130° and a hydrophilic surface on one side.

[0026] The absorbent core layer is manufactured using the following principle: a dust-free paper machine is used, with sodium alginate as the raw material (pulp concentration 4%). The paper is formed into a cotton-like paper (35 g / m²) through airflow (wind speed 13.5 m / s) and hot-pressed for curing (temperature 115℃, pressure 0.25 MPa). 2 (0.25mm thick) as the absorbent (dosage 17.5g / m³) 2 (Particles with a diameter of 0.2 mm) form a preliminary absorption layer. A photo before water absorption is shown below. Figure 1 As shown, after absorbing water... Figure 2 As shown.

[0027] The surface layer uses seaweed fiber nonwoven fabric, with perforations to enhance liquid permeation speed (permeation time ≤ 2s). The bottom membrane uses a breathable PE membrane, unwound using an unwinding machine to maintain stable tension (6.5N). In the multi-layer lamination and anti-leakage molding stage, the following sequence is used: surface layer → upper anti-reverse osmosis functional layer (water-repellent side up, hydrophilic side down) → absorbent core layer → lower anti-reverse osmosis functional layer (water-repellent side down, hydrophilic side up) → bottom membrane. This is achieved through hot-pressing with a five-roll laminator (temperature 75℃, pressure 0.35MPa, lamination speed 17.5m / min, ensuring interlayer peel strength ≥ 3N / 15mm). On both sides of the laminated roll, nonwoven leak-proof edge sealers are added using an ultrasonic sealing machine (ultrasonic frequency 22.5kHz), with a sealing strength ≥ 2N / 15mm, forming a three-dimensional leak-proof barrier (side leakage test: placed at a 30° angle, injected with 50mL of simulated blood, no side leakage). In the post-processing and quality inspection stage, the composite roll material is cut into individual sanitary napkins (260mm in length, 70mm in width, cutting accuracy ±0.5mm) using a rotary cutter. The integrity of each layer, the sealing performance of the leak-proof side panels, the uniformity of thickness (deviation ≤0.1mm), the absorbency (absorbency ≥800%, reverse osmosis ≤0.1g, reverse osmosis rate ≤5%), and the production qualification rate (≥98%) are tested. This technical solution prevents reverse leakage of liquid through the single-sided water-repellent properties of the anti-reverse osmosis functional layer and physically blocks side leakage through the three-dimensional leak-proof side panels. Natural antibacterial properties are achieved through the natural antibacterial components (such as seaweed polysaccharides) contained in the seaweed fiber itself, eliminating the need for added chemical antibacterial agents and ensuring higher safety. Each process step is controlled by specialized equipment to ensure stable and repeatable functionality.

[0028] The absorbency of the seaweed fiber absorbent sanitary napkin in this embodiment was tested. When the amount of seaweed fiber super absorbent material added was 5g, the sanitary napkin could absorb more than 50 times its weight in water, which is higher than the absorbency requirement of sanitary napkins specified in GB / T8939-2008 (standard requirement ≥7).

[0029] Example 2 The overall structure of a sanitary napkin, from top to bottom, is as follows: Surface layer (using 23g / m²) 2 The seaweed fiber nonwoven fabric has inherent antibacterial properties and features a diameter of 0.7mm and a pore density of 38 pores / cm². 2 (vent holes) The upper anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 48g / m²) 2 Apply a water-repellent finishing agent to one side (mass fraction: 14% waterborne polyurethane, 7.5% waterborne carnauba wax emulsion, 4.5% polydimethylsiloxane PEG-10-15 crosslinked polymer, balance deionized water), with the water-repellent side facing up and the hydrophilic side facing down, and a contact angle ≥130°. Absorbent core layer (including cotton-like paper (0.28mm thick), seaweed fiber absorbent (sodium alginate copolymer), antibacterial rate: ≥90% against Escherichia coli and Staphylococcus aureus, with a continuous antibacterial time of ≥8h) The lower anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 48g / m²) 2 A water-repellent finishing agent is sprayed on one side (mass fraction: 14% waterborne polyurethane, 7.5% waterborne carnauba wax emulsion, 4.5% polydimethylsiloxane PEG-10-15 cross-linked polymer, balance deionized water), with the water-repellent side facing down and the hydrophilic side facing up, and a contact angle ≥130°. Bottom film (breathable PE film, 0.018mm thick) And the side leakage prevention partitions located on both sides (non-woven fabric three-dimensional structure, 9.5mm wide and 4.5mm high).

[0030] The production process includes raw material pretreatment, anti-reverse osmosis functional layer fabrication, absorbent core layer fabrication, surface and bottom membrane treatment, multi-layer composite and anti-side leakage molding, post-processing and quality inspection.

[0031] In the raw material pretreatment stage, the core raw materials include seaweed fiber with a length of 4.5 mm and a fineness of 1.45 dtex, cotton fiber with a length of 3.5 mm and a fineness of 1.15 dtex, cotton-like paper, seaweed absorbent, water-repellent finishing agent, breathable PE bottom film, and seaweed fiber nonwoven fabric surface layer.

[0032] The seaweed raw materials (brown algae / red algae) were washed (water temperature 34℃, washing time 7.5min), crushed (speed 1500r / min, crushed to particle size ≤5mm), extracted by alkaline method (NaOH solution mass fraction 2.8%, constant temperature extraction at 84℃ for 2h, seaweed fiber was separated), bleached (hydrogen peroxide mass fraction 1.8%, pH value 9.8, treatment at 60℃ for 30min) and dried (hot air temperature 68℃, moisture content controlled at 9.5%).

[0033] Cotton fibers are opened using a fiber opener (800 rpm) to remove knots and impurities. Then, they are thoroughly mixed with seaweed fibers in a blender at a 3:7 mass ratio (mixing time 14 min, uniformity ≥95%). For the anti-reverse osmosis functional layer, the mixed fibers are carded into a single-fiber web (carding speed 19 m / min, web thickness 0.45 mm). After being layered by a web-laying machine (5 layers, web-laying speed 19 m / min, total thickness 1.15 mm), they are bonded using a hot air bonding machine (hot air temperature 130℃, air velocity 14 m / s, bonding time 38 s) to form a nonwoven fabric base (48 g / m²). 2 Then, a single-sided spraying machine was used to evenly spray the water-repellent finishing agent onto one side of the nonwoven fabric (spraying amount 9.5g / m²).2 The coating is applied at a pressure of 0.38 MPa and then dried in an oven at 88°C for 2.8 minutes to form a functional layer with a water-repellent surface contact angle of ≥130° and a hydrophilic surface on one side.

[0034] The absorbent core layer is manufactured using the following principle: a dust-free paper machine is used, with sodium alginate as the raw material (pulp concentration 4.5%), which is formed into a web by airflow (wind speed 14m / s) and then cured by hot pressing (temperature 118℃, pressure 0.28MPa) to produce cotton-like paper (grammage 38g / m²). 2 (Thickness 0.28mm). As an absorbent (dosage 19g / m³). 2 A preliminary absorption layer is formed by particles with a diameter of 0.25 mm.

[0035] The surface layer uses seaweed fiber nonwoven fabric, with perforations to enhance liquid permeation speed (permeation time ≤ 2s). The bottom membrane uses a breathable PE membrane, unwound using an unwinding machine to maintain stable tension (7.2N). In the multi-layer lamination and anti-leakage molding stage, the following sequence is used: surface layer → upper anti-reverse osmosis functional layer (water-repellent side up, hydrophilic side down) → absorbent core layer → lower anti-reverse osmosis functional layer (water-repellent side down, hydrophilic side up) → bottom membrane. This is achieved through hot-pressing with a five-roll laminator (temperature 78℃, pressure 0.38MPa, lamination speed 19m / min, ensuring interlayer peel strength ≥ 3N / 15mm). On both sides of the laminated roll, nonwoven leak-proof edge sealers are added using an ultrasonic sealing machine (ultrasonic frequency 24kHz), with a sealing strength ≥ 2N / 15mm, forming a three-dimensional leak-proof barrier (side leakage test: placed at a 30° angle, injected with 50mL of simulated blood, no side leakage). In the post-processing and quality inspection stage, the composite roll material is cut into individual sanitary napkins (270mm in length, 75mm in width, cutting accuracy ±0.5mm) using a rotary cutter. The integrity of each layer, the sealing performance of the leak-proof side panels, the uniformity of thickness (deviation ≤0.1mm), the absorbency (absorbency ≥800%, reverse osmosis ≤0.1g, reverse osmosis rate ≤5%), and the production qualification rate (≥98%) are tested. This technical solution prevents reverse leakage of liquid through the single-sided water-repellent properties of the anti-reverse osmosis functional layer and physically blocks side leakage through the three-dimensional leak-proof side panels. Natural antibacterial properties are achieved through the natural antibacterial components (such as seaweed polysaccharides) contained in the seaweed fiber itself, eliminating the need for added chemical antibacterial agents and resulting in higher safety. Each process step is controlled by specialized equipment to ensure stable and repeatable functionality.

[0036] Example 3 The overall structure of a sanitary napkin, from top to bottom, is as follows: Surface layer (using 21g / m²) 2 The seaweed fiber nonwoven fabric has a certain degree of antibacterial properties and features a diameter of 0.55mm and a pore density of 32 pores / cm². 2 (vent holes) The upper anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 42g / m²) 2 Apply a water-repellent finishing agent to one side (mass fraction: 11% waterborne polyurethane, 5.5% waterborne carnauba wax emulsion, 3.5% polydimethylsiloxane PEG-10-15 cross-linked polymer, balance deionized water), with the water-repellent side facing up and the hydrophilic side facing down, and a contact angle ≥130°. Absorbent core layer (comprising cotton-like paper (0.22mm thick), seaweed fiber absorbent (sodium alginate copolymer), antibacterial rate: ≥90% against Escherichia coli and Staphylococcus aureus, with a sustained antibacterial time of ≥8h) The lower anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 42g / m²) 2 A water-repellent finishing agent is sprayed on one side (mass fraction: 11% waterborne polyurethane, 5.5% waterborne carnauba wax emulsion, 3.5% polydimethylsiloxane PEG-10-15 cross-linked polymer, balance deionized water), with the water-repellent side facing down and the hydrophilic side facing up, and a contact angle ≥130°. Bottom film (breathable PE film, 0.012mm thick) And the side leakage prevention partitions located on both sides (non-woven fabric three-dimensional structure, 8.5mm wide and 3.5mm high).

[0037] The production process includes raw material pretreatment, anti-reverse osmosis functional layer fabrication, absorbent core layer fabrication, surface and bottom membrane treatment, multi-layer composite and anti-side leakage molding, post-processing and quality inspection.

[0038] In the raw material pretreatment stage, the core raw materials include seaweed fiber with a length of 3.5 mm and a fineness of 1.25 dtex, cotton fiber with a length of 2.5 mm and a fineness of 1.05 dtex, cotton-like paper, seaweed fiber absorbent, water-repellent finishing agent, breathable PE bottom film, and seaweed fiber nonwoven fabric surface layer.

[0039] The seaweed raw materials (brown algae / red algae) were washed (water temperature 31℃, washing time 5.5min), crushed (speed 1500r / min, crushed to particle size ≤5mm), extracted by alkaline method (NaOH solution mass fraction 2.2%, constant temperature extraction at 81℃ for 2h, seaweed fiber was separated), bleached (hydrogen peroxide mass fraction 1.2%, pH value 9.2, treatment at 60℃ for 30min) and dried (hot air temperature 62℃, moisture content controlled at 8.5%).

[0040] Cotton fibers are opened using a fiber opener (800 rpm) to remove knots and impurities. Then, they are thoroughly mixed with seaweed fibers in a blender at a 3:7 mass ratio (mixing time 11 min, uniformity ≥95%). For the anti-reverse osmosis functional layer, the mixed fibers are carded into a single-fiber web (carding speed 16 m / min, web thickness 0.35 mm). After being layered by a web-laying machine (3 layers, web-laying speed 16 m / min, total thickness 1.05 mm), they are bonded using a hot air bonding machine (hot air temperature 130℃, air velocity 11 m / s, bonding time 32 s) to form a nonwoven fabric base (42 g / m²). 2 Then, a single-sided spraying machine was used to evenly spray the water-repellent finishing agent onto one side of the nonwoven fabric (spraying amount 8.5g / m²). 2 The coating is applied at a pressure of 0.32 MPa and then dried in an oven at 82°C for 2.2 min to form a functional layer with a water-repellent surface contact angle ≥130° and one side being water-repellent and the other side being hydrophilic.

[0041] The absorbent core layer is manufactured using the following principle: a dust-free paper machine is used, with sodium alginate as the raw material (pulp concentration 3.5%), which is formed into a web by airflow (wind speed 13m / s) and then cured by hot pressing (temperature 112℃, pressure 0.22MPa) to produce cotton-like paper (grammage 32g / m²). 2 (Thickness 0.22mm). As an absorbent (dosage 16g / m³). 2 A preliminary absorption layer is formed by particles with a diameter of 0.15 mm.

[0042] The surface layer uses seaweed fiber nonwoven fabric, with perforations to enhance liquid permeation speed (permeation time ≤ 2s). The bottom membrane uses a breathable PE membrane, unwound using an unwinding machine to maintain stable tension (5.8N). In the multi-layer lamination and anti-leakage molding stage, the following sequence is used: surface layer → upper anti-reverse osmosis functional layer (water-repellent side up, hydrophilic side down) → absorbent core layer → lower anti-reverse osmosis functional layer (water-repellent side down, hydrophilic side up) → bottom membrane. This is achieved through hot-pressing with a five-roll laminator (temperature 72℃, pressure 0.32MPa, lamination speed 16m / min, ensuring interlayer peel strength ≥ 3N / 15mm). On both sides of the laminated roll, nonwoven leak-proof edge sealers are added using an ultrasonic sealing machine (ultrasonic frequency 21kHz), with a sealing strength ≥ 2N / 15mm, forming a three-dimensional leak-proof barrier (side leakage test: placed at a 30° angle, injected with 50mL of simulated blood, no side leakage). In the post-processing and quality inspection stage, the composite roll material is cut into individual sanitary napkins (250mm in length, 65mm in width, cutting accuracy ±0.5mm) using a rotary cutter. The integrity of each layer, the sealing performance of the leak-proof side panels, the uniformity of thickness (deviation ≤0.1mm), the absorbency (absorbency ≥800%, reverse osmosis ≤0.1g, reverse osmosis rate ≤5%), and the production qualification rate (≥98%) are tested. This technical solution prevents reverse leakage of liquid through the single-sided water-repellent properties of the anti-reverse osmosis functional layer and physically blocks side leakage through the three-dimensional leak-proof side panels. Natural antibacterial properties are achieved through the natural antibacterial components (such as seaweed polysaccharides) contained in the seaweed fiber itself, eliminating the need for added chemical antibacterial agents and resulting in higher safety. Each process step is controlled by specialized equipment to ensure stable and repeatable functionality.

[0043] Example 4 The overall structure of a sanitary napkin, from top to bottom, is as follows: Surface layer (using 24g / m²) 2 The seaweed fiber nonwoven fabric has a certain degree of antibacterial properties and features a diameter of 0.75mm and a pore density of 39 pores / cm². 2 (vent holes) The upper anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 49g / m²) 2 A water-repellent finishing agent is sprayed on one side (mass fraction: 14.5% waterborne polyurethane, 7.8% waterborne carnauba wax emulsion, 4.8% polydimethylsiloxane PEG-10-15 cross-linked polymer, balance deionized water), with the water-repellent side facing up and the hydrophilic side facing down, and a contact angle ≥130°. Absorbent core layer (including cotton-like paper (0.29mm thick), seaweed fiber absorbent (sodium alginate copolymer), antibacterial rate: ≥90% against Escherichia coli and Staphylococcus aureus, with a continuous antibacterial time of ≥8h) The lower anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 49g / m²) 2 A water-repellent finishing agent is sprayed on one side (mass fraction: 14.5% waterborne polyurethane, 7.8% waterborne carnauba wax emulsion, 4.8% polydimethylsiloxane PEG-10-15 cross-linked polymer, balance deionized water), with the water-repellent side facing down and the hydrophilic side facing up, and a contact angle ≥130°. Bottom film (breathable PE film, 0.019mm thick) And the side leakage prevention partitions located on both sides (non-woven fabric three-dimensional structure, 9.8mm wide and 4.8mm high).

[0044] Each layer is tightly connected by hot-pressing composite, and the anti-leakage partition is in an arc-shaped protrusion, forming a surrounding anti-leakage barrier.

[0045] The production process includes raw material pretreatment, anti-reverse osmosis functional layer fabrication, absorbent core layer fabrication, surface and bottom membrane treatment, multi-layer composite and anti-side leakage molding, post-processing and quality inspection.

[0046] In the raw material pretreatment stage, the core raw materials include seaweed fiber with a length of 5mm and a fineness of 1.5dtex, cotton fiber with a length of 4mm and a fineness of 1.2dtex, cotton-like paper, seaweed fiber absorbent, water-repellent finishing agent, breathable PE bottom film, and seaweed fiber nonwoven fabric surface layer.

[0047] The seaweed raw materials (brown algae / red algae) were washed (water temperature 35℃, washing time 8min), crushed (speed 1500r / min, crushed to particle size ≤5mm), extracted by alkaline method (NaOH solution mass fraction 2.9%, constant temperature extraction at 84.5℃ for 2h, seaweed fiber was separated), bleached (hydrogen peroxide mass fraction 1.8%, pH value 10, treatment at 60℃ for 30min) and dried (hot air temperature 70℃, moisture content controlled at 10%).

[0048] Cotton fibers are opened using a fiber opener (800 rpm) to remove knots and impurities. Then, they are thoroughly mixed with seaweed fibers in a blender at a 3:7 mass ratio (mixing time 15 min, uniformity ≥95%). For the anti-reverse osmosis functional layer, the mixed fibers are carded into a single-fiber web (carding speed 20 m / min, web thickness 0.5 mm). After being layered by a web-laying machine (5 layers, web-laying speed 20 m / min, total thickness 1.2 mm), they are bonded using a hot air bonding machine (hot air temperature 130℃, air velocity 15 m / s, bonding time 40 s) to form a nonwoven fabric base (49 g / m²). 2 Subsequently, a single-sided spraying machine was used to evenly spray the water-repellent finishing agent onto one side of the nonwoven fabric (spraying amount 10g / m²). 2The coating is applied at a pressure of 0.4 MPa and then dried in an oven at 90°C for 3 minutes to form a functional layer with a water-repellent surface contact angle of ≥130° and a hydrophilic surface on one side.

[0049] The absorbent core layer is manufactured using the following principle: a dust-free paper machine is used, with sodium alginate as the raw material (pulp concentration 5%), which is formed into a web by airflow (wind speed 15m / s) and then cured by hot pressing (temperature 120℃, pressure 0.3MPa) to produce cotton-like paper (grammage 40g / m²). 2 (Thickness 0.29mm). As an absorbent (dosage 20g / m³). 2 A preliminary absorption layer is formed by particles with a diameter of 0.3 mm.

[0050] The surface layer uses seaweed fiber nonwoven fabric, with perforations to enhance liquid permeation speed (permeation time ≤ 2s). The bottom membrane uses a breathable PE membrane, unwound using an unwinding machine to maintain stable tension (8N). In the multi-layer lamination and anti-leakage molding stage, the following sequence is used: surface layer → upper anti-reverse osmosis functional layer (water-repellent side up, hydrophilic side down) → absorbent core layer → lower anti-reverse osmosis functional layer (water-repellent side down, hydrophilic side up) → bottom membrane. This is achieved through hot-pressing with a five-roll laminator (temperature 80℃, pressure 0.4MPa, lamination speed 20m / min, ensuring interlayer peel strength ≥ 3N / 15mm). On both sides of the laminated roll, nonwoven leak-proof edge sealers are added using an ultrasonic sealing machine (ultrasonic frequency 25kHz), with a sealing strength ≥ 2N / 15mm, forming a three-dimensional leak-proof barrier (side leakage test: placed at a 30° angle, injected with 50mL of simulated blood, no side leakage). In the post-processing and quality inspection stage, the composite roll material is cut into individual sanitary napkins (280mm in length, 80mm in width, cutting accuracy ±0.5mm) using a rotary cutter. The integrity of each layer, the sealing performance of the leak-proof side panels, the uniformity of thickness (deviation ≤0.1mm), the absorbency (absorbency ≥800%, reverse osmosis ≤0.1g, reverse osmosis rate ≤5%), and the production qualification rate (≥98%) are tested. This technical solution prevents reverse leakage of liquid through the single-sided water-repellent properties of the anti-reverse osmosis functional layer and physically blocks side leakage through the three-dimensional leak-proof side panels. Natural antibacterial properties are achieved through the natural antibacterial components (such as seaweed polysaccharides) contained in the seaweed fiber itself, eliminating the need for added chemical antibacterial agents and resulting in higher safety. Each process step is controlled by specialized equipment to ensure stable and repeatable functionality.

[0051] Example 5 The overall structure of a sanitary napkin, from top to bottom, is as follows: Surface layer (using a weight of 20.5 g / m²) 2 The seaweed fiber nonwoven fabric has a certain degree of antibacterial properties and features a diameter of 0.52mm and a pore density of 31 pores / cm². 2 (vent holes) The upper anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 41g / m²) 2 A water-repellent finishing agent is sprayed on one side (mass fraction: 10.5% waterborne polyurethane, 5.2% waterborne carnauba wax emulsion, 3.2% polydimethylsiloxane PEG-10-15 cross-linked polymer, balance deionized water), with the water-repellent side facing up and the hydrophilic side facing down, and a contact angle ≥130°. Absorbent core layer (including cotton-like paper (0.21mm thick), seaweed fiber absorbent (sodium alginate copolymer), antibacterial rate: ≥90% against Escherichia coli and Staphylococcus aureus, with a continuous antibacterial time of ≥8h) The lower anti-reverse osmosis functional layer (a non-woven fabric made of seaweed fiber and cotton fiber in a mass ratio of 3:7, with a basis weight of 41g / m²) 2 A water-repellent finishing agent is sprayed on one side (mass fraction: 10.5% waterborne polyurethane, 5.2% waterborne carnauba wax emulsion, 3.2% polydimethylsiloxane PEG-10-15 cross-linked polymer, balance deionized water), with the water-repellent side facing down and the hydrophilic side facing up, and a contact angle ≥130°. Bottom film (breathable PE film, 0.011mm thick) And the side leakage prevention partitions located on both sides (non-woven fabric three-dimensional structure, 8.2mm wide and 3.2mm high).

[0052] Each layer is tightly connected by hot-pressing composite, and the anti-leakage partition is in an arc-shaped protrusion, forming a surrounding anti-leakage barrier.

[0053] The production process includes raw material pretreatment, anti-reverse osmosis functional layer fabrication, absorbent core layer fabrication, surface and bottom membrane treatment, multi-layer composite and anti-side leakage molding, post-processing and quality inspection.

[0054] In the raw material pretreatment stage, the core raw materials include seaweed fiber with a length of 3mm and a fineness of 1.2dtex, cotton fiber with a length of 2mm and a fineness of 1.0dtex, cotton-like paper, seaweed fiber absorbent, water-repellent finishing agent, breathable PE bottom film, and seaweed fiber nonwoven fabric surface layer.

[0055] The seaweed raw materials (brown algae / red algae) were washed (water temperature 30℃, washing time 5min), crushed (speed 1500r / min, crushed to particle size ≤5mm), extracted by alkaline method (NaOH solution mass fraction 2.0%, constant temperature extraction at 80℃ for 2h, seaweed fiber was separated), bleached (hydrogen peroxide mass fraction 1.0%, pH value 9, treatment at 60℃ for 30min) and dried (hot air temperature 60℃, moisture content controlled at 8%).

[0056] Cotton fibers are opened using a fiber opener (800 rpm) to remove knots and impurities. Then, they are thoroughly mixed with seaweed fibers in a blender at a 3:7 mass ratio (mixing time 10 min, uniformity ≥95%). For the anti-reverse osmosis functional layer, the mixed fibers are carded into a single-fiber web (carding speed 15 m / min, web thickness 0.3 mm). After being layered by a web-laying machine (3 layers, web-laying speed 15 m / min, total thickness 1.0 mm), they are bonded using a hot air bonding machine (hot air temperature 130℃, air velocity 10 m / s, bonding time 30 s) to form a nonwoven fabric base (41 g / m²). 2 Subsequently, a single-sided spraying machine was used to evenly spray the water-repellent finishing agent onto one side of the nonwoven fabric (spraying amount 8g / m²). 2 The coating is applied at a pressure of 0.3 MPa and then dried in an oven at 80°C for 2 minutes to form a functional layer with a water-repellent surface contact angle of ≥130° and a hydrophilic surface on one side.

[0057] The absorbent core layer is manufactured using the following principle: a dust-free paper machine is used, with sodium alginate as the raw material (pulp concentration 3%), which is formed into a web by airflow (wind speed 12m / s) and then cured by hot pressing (temperature 110℃, pressure 0.2MPa) to produce cotton-like paper (weight 30g / m²). 2 (Thickness 0.21mm). As an absorbent (dosage 15g / m³). 2 A preliminary absorption layer is formed by particles with a diameter of 0.1 mm.

[0058] The surface layer uses seaweed fiber nonwoven fabric, with perforations to enhance liquid permeation speed (permeation time ≤ 2s). The bottom membrane uses a breathable PE membrane, unwound using an unwinding machine to maintain stable tension (5N). In the multi-layer lamination and anti-leakage molding stage, the following sequence is used: surface layer → upper anti-reverse osmosis functional layer (water-repellent side up, hydrophilic side down) → absorbent core layer → lower anti-reverse osmosis functional layer (water-repellent side down, hydrophilic side up) → bottom membrane. This is achieved through hot-pressing with a five-roll laminator (temperature 70℃, pressure 0.3MPa, lamination speed 15m / min, ensuring interlayer peel strength ≥ 3N / 15mm). On both sides of the laminated roll, nonwoven leak-proof edge sealers are added using an ultrasonic sealing machine (ultrasonic frequency 20kHz), with a sealing strength ≥ 2N / 15mm, forming a three-dimensional leak-proof barrier (side leakage test: placed at a 30° angle, injected with 50mL of simulated blood, no side leakage). In the post-processing and quality inspection stage, the composite roll material is cut into individual sanitary napkins (240mm in length, 60mm in width, cutting accuracy ±0.5mm) using a rotary cutter. The integrity of each layer, the sealing performance of the leak-proof side panels, the uniformity of thickness (deviation ≤0.1mm), the absorbency (absorbency ≥800%, reverse osmosis ≤0.08g, reverse osmosis rate ≤5%), and the production qualification rate (≥98%) are tested. This technical solution prevents reverse leakage of liquid through the single-sided water-repellent properties of the anti-reverse osmosis functional layer and physically blocks side leakage through the three-dimensional leak-proof side panels. Natural antibacterial properties are achieved through the natural antibacterial components (such as seaweed polysaccharides) contained in the seaweed fiber itself, eliminating the need for added chemical antibacterial agents and resulting in higher safety. Each process step is controlled by specialized equipment to ensure stable and repeatable functionality.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A sanitary napkin, characterized in that, The overall structure consists of, from top to bottom, a surface layer, an upper anti-reverse osmosis functional layer, an absorbent core layer, a lower anti-reverse osmosis functional layer, a bottom membrane, and anti-leakage barriers located on both sides; each layer is tightly connected by hot-pressing composite, and the anti-leakage barriers are in an arc-shaped convex state to form a surrounding anti-leakage barrier; Both the upper and lower anti-reverse osmosis functional layers are non-woven fabrics, which are coated with a water-repellent finishing agent on one side to form a water-repellent and hydrophilic property on the other. The nonwoven fabric is made by mixing seaweed fiber and cotton fiber in a mass ratio of 0.1 to 100:1; The upper anti-reverse osmosis functional layer has its water-repellent surface facing upwards and its hydrophilic surface facing downwards, while the lower anti-reverse osmosis functional layer has its water-repellent surface facing downwards and its hydrophilic surface facing upwards. The absorbent core layer contains seaweed fiber absorbers.

2. The sanitary napkin according to claim 1, characterized in that, The surface layer has a weight of 10-90 g / m². 2 Seaweed fiber nonwoven fabric.

3. The sanitary napkin according to claim 1, characterized in that, The water-repellent finishing agent comprises the following components in parts by weight: 8-18 parts of waterborne polyurethane, 4-10 parts of waterborne carnauba wax emulsion, 2-6 parts of polydimethylsiloxane PEG-10-15 crosslinked polymer, and 10-100 parts of deionized water.

4. The sanitary napkin according to claim 1, characterized in that, The preparation method of the seaweed fiber absorbent includes the following steps: Cotton-like paper is made from seaweed fiber as raw material, formed by airflow at a wind speed of 10~18m / s, hot-pressed and cured at a temperature of 100~130℃ and a pressure of 0.1~0.4MPa.

5. The sanitary napkin according to claim 1, characterized in that, The base film is a breathable PE film with a thickness of 0.008~0.025mm.

6. The sanitary napkin according to claim 1, characterized in that, The anti-leakage partition is a non-woven fabric three-dimensional structure with a width of 5~15mm and a height of 2~6mm.

7. The method for preparing a sanitary napkin according to any one of claims 1 to 6, characterized in that, Includes the following steps: (a) Raw material pretreatment: treating seaweed fiber surface layer, cotton fiber, cotton paper, seaweed fiber absorbent, breathable PE bottom film and seaweed fiber non-woven fabric surface layer; (b) Fabrication of the anti-reverse osmosis functional layer; (c) Fabrication of the absorbent core layer; (d) Topcoat and basecoat treatment; (e) Multi-layer composite and anti-leakage molding; (f) Post-processing.

8. The preparation method according to claim 7, characterized in that, The pretreatment of seaweed fibers in step (a) includes: Cleaning: Water temperature 25~40℃, time 4~10 minutes; Crushing: Rotation speed 1200~1800 r / min, crush to particle size ≤10mm; Alkaline extraction: NaOH solution mass fraction 1~5%, temperature 75~90℃, constant temperature extraction for 1.5~3h; Bleaching: Hydrogen peroxide mass fraction 0.5~3%, pH value 8~11, temperature 50~70℃ for 20-40 min; Drying: Hot air temperature 55~75℃, so that the moisture content is controlled at 5~12%.

9. The preparation method according to claim 7, characterized in that, Step (b) specifically includes: Seaweed fiber and cotton fiber are mixed at a mass ratio of 0.1 to 100:1, and then carded to form a single fiber web at a carding speed of 10 to 25 m / min and a web thickness of 0.2 to 0.6 mm. The mesh is laid in 3 to 6 layers at a speed of 10 to 25 m / min, with a total thickness of 0.8 to 1.5 mm. Hot air bonding: temperature 120~140℃, wind speed 8~18m / s, time 25~50s, to form a non-woven fabric substrate; Apply water-repellent finishing agent to one side, with a spraying amount of 6~12g / m². 2 Spraying pressure: 0.2~0.5MPa; Drying and curing: Temperature 70~100℃, time 1~5min.

10. The preparation method according to claim 7, characterized in that, Step (c) specifically includes: Using seaweed fiber as raw material, it is made into cotton-like paper through airflow forming at a wind speed of 10~18m / s, hot pressing and curing at a temperature of 100~130℃ and a pressure of 0.1~0.4MPa, and used as a seaweed fiber water absorbent. Step (d) specifically includes: Surface treatment: Perforate the seaweed fiber nonwoven fabric with ventilation holes; Bottom film treatment: The unwinding tension of the breathable PE bottom film is controlled at 3-10N; Step (e) specifically includes: The layers are stacked in the following order: surface layer → upper anti-reverse osmosis functional layer → absorbent core layer → lower anti-reverse osmosis functional layer → bottom membrane. Hot pressing composite: temperature 65-85℃, pressure 0.2-0.5MPa, composite speed 10-25m / min; Non-woven fabric leak-proof barriers are added to both sides of the composite layer, and a three-dimensional barrier is formed by ultrasonic sealing with a sealing frequency of 18-28kHz.

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