Directional moisture-wicking nonwoven fabric and its preparation method, as well as disposable hygiene products

Abstract

This invention discloses a directional moisture-wicking nonwoven fabric, its preparation method, and disposable hygiene products. The upper fiber web has a core-sheath structure composed of two types of fibers: hydrophobic and hydrophilic fibers, which are uniformly mixed and combed, with the ratio of hydrophobic fibers to hydrophilic fibers being 1:0.2–5. The lower fiber web has a core-sheath structure composed of high- and low-melting-point fibers, consisting of eccentric fibers and hollow fibers, which are uniformly mixed and combed, with the ratio of eccentric fibers to hollow fibers being 1:0.5–2. The contact angle θ1 between a wettable droplet on the surface of the upper fiber web and a solid surface, and the equivalent radius r1 of the interfiber gap, satisfy θ2 < θ1 < 90° and cosθ1 / r1. <cosθ 22 / r2; The fiber disorder of the upper fiber web is greater than that of the lower fiber web. Hot air penetrates from the lower fiber web to the upper fiber web to reinforce the double-layer fiber web. The nonwoven fabric prepared by this invention has the characteristics of being soft, having low surface diffusion, blocking menstrual blood, allowing liquid to seep in quickly, and having low moisture return.

Description

Technical Field Background Technology

[0001] Nonwoven fabrics, as materials that come into direct contact with the human body, play a crucial role in disposable hygiene products. Currently, the use of nonwoven fabrics for the surface layer in diapers or sanitary napkins presents a trade-off between softness, liquid absorption, and a moist feel. The most effective solution for achieving a soft feel is to use fine denier surface fibers; however, fine denier fibers often result in poor liquid absorption and retention, affecting the user experience. At the same time, the widespread use of disposable hygiene products also places significant pressure on the environment. Summary of the Invention

[0002] To overcome the above-mentioned defects, the present invention provides a directional moisture-wicking nonwoven fabric and its preparation method.

[0003] To achieve the above objectives, the directional moisture-wicking nonwoven fabric of the present invention is reinforced with a double-layer fiber web; wherein,

[0004] The upper fiber web is a bicomponent fiber with a core-sheath structure, consisting of a PBAT or PBS sheath and a PLA core, with a fiber denier of 0.6D to 1.5D.

[0005] The lower fiber web is composed of high- and low-melting-point fibers with a sheath-core structure consisting of a low-melting-point PLA sheath and a high-melting-point PLA core, with a fiber denier of 1.5D to 6.0D.

[0006] The core-sheath structure of the upper fiber web consists of two types of fibers: hydrophobic and hydrophilic. The two types of fibers are uniformly mixed and combed, with the ratio of hydrophobic fiber to hydrophilic fiber being 1:0.2 to 5.

[0007] The core-sheath structure of the lower fiber web consists of high and low melting point fibers composed of eccentric fibers and hollow fibers, which are uniformly mixed and combed; the ratio of eccentric fibers to hollow fibers is 1:0.5 to 2.

[0008] The contact angle θ1 between a wettable droplet on the surface of the upper fiber web and the solid surface, and the equivalent radius r1 of the inter-fiber void; the contact angle θ2 between a wettable droplet on the surface of the lower fiber web and the solid surface, and the equivalent radius r2 of the inter-fiber void, satisfying θ2 < θ1 < 90° and cosθ1 / r1 <cosθ2 / r2;

[0009] The fiber disorder of the upper fiber web is greater than that of the lower fiber web. Hot air penetrates from the lower fiber web to the upper fiber web to reinforce the double-layer fiber web.

[0010] Furthermore, TiO2 is added to the PBAT or PBS.

[0011] To achieve the above objectives, the disposable hygiene product of the present invention has a surface layer made of the moisture-wicking nonwoven fabric as described in claim 1.

[0012] To achieve the above objectives, the present invention provides a method for preparing a directional moisture-wicking nonwoven fabric, the method comprising the following steps:

[0013] Prepare the upper layer fiber; the upper layer fiber is a bicomponent fiber with a core-shell structure consisting of a PBAT or PBS sheath and a PLA core, with a fiber denier of 0.6D to 1.5D;

[0014] Prepare the lower layer fiber; the lower layer fiber is a high-low melting point fiber with a sheath-core structure composed of a low melting point PLA sheath layer and a high melting point PLA core layer, with a fiber denier of 1.5D to 6.0D;

[0015] The core-sheath structure bicomponent fiber is prepared into two types of fibers: hydrophobic and hydrophilic. The two types of fibers are uniformly mixed and combed to prepare an upper fiber web, wherein the ratio of hydrophobic fiber to hydrophilic fiber in the upper fiber web is 1:0.2~5.

[0016] High and low melting point fibers with a core-sheath structure are prepared into eccentric fibers and hollow fibers. The two types of fibers are uniformly mixed and combed to prepare a lower fiber web. The ratio of eccentric fibers to hollow fibers in the lower fiber web is 1:0.5~2.

[0017] Hot air penetrates from the lower fiber web to the upper fiber web to reinforce the double-layer fiber web, wherein the fiber disorder of the upper fiber web is greater than that of the lower fiber web;

[0018] The contact angle θ1 between the wettable droplet on the surface of the upper fiber web and the solid surface, and the equivalent radius r1 of the inter-fiber gap; the contact angle θ2 between the wettable droplet on the surface of the lower fiber web and the solid surface, and the equivalent radius r2 of the inter-fiber gap, satisfy θ2 < θ1 < 90° and cosθ1 / r1 <cosθ2 / r2;。

[0019] Furthermore, TiO2 is added to the PBAT or PBS.

[0020] This invention utilizes the softness, rigidity, and melting point characteristics of PBAT (PBS) and high- and low-melting-point PLA fibers to prepare a unidirectional, biodegradable hot-air nonwoven fabric composed of an upper layer of soft, fine-denier fiber web and a lower layer of rigid, coarse-denier fiber web. The relationship between the surface energy and capillary properties of the upper and lower fiber layers is established to achieve rapid liquid penetration, while the three-dimensional, fluffy structure composed of the lower layer of eccentric and hollow fibers prevents liquid re-wetting. Simultaneously, techniques are employed to block liquid diffusion in the upper fiber web and to lighten the color of the whitening fibers, resulting in a nonwoven fabric characterized by softness, minimal surface diffusion, effective concealment of menstrual blood, rapid liquid penetration, and low re-wetting. Attached Figure Description

[0021] Figure 1This is a comparison diagram of monofilament + yarn versus monofilament and yarn as the support layer in this invention. Detailed Implementation

[0022] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0023] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] Example 1

[0027] The nonwoven fabric of the present invention is formed by reinforcement of a double-layer fiber web; wherein,

[0028] The upper fiber web is a bicomponent fiber with a core-sheath structure, consisting of a PBAT sheath and a PLA core, with a denier of 0.6D to 1.5D. The PBAT sheath provides a soft touch, while the PLA core provides good rigidity. Alternatively, the upper fiber web can be a bicomponent fiber with a PBS sheath and a PLA core, also with a denier of 0.6D to 1.5D. The PBS sheath provides a soft touch, while the PLA core provides good rigidity.

[0029] The lower fiber web is composed of a sheath-core structure of high and low melting point fibers, consisting of a sheath layer of low melting point PLA (melting point 127℃~133℃) and a core layer of high melting point PLA (160℃~180℃), with a fiber denier of 1.5D~6.0D.

[0030] The core - sheath structured bicomponent fibers of the upper fiber web are composed of two types of fibers, water - repellent and hydrophilic fibers. The two types of fibers are evenly mixed and carded. The ratio of water - repellent fibers to hydrophilic fibers is 1:0.2 - 5; for example: 1:0.4; 1:0.5; 1:0.7; 1:0.9; 1:1.5; 1:2; 1:2.5; 1:3; 1:4; 1:5, etc. By using the hydrophilic fibers and water - repellent fibers to surround and divide each other, the diffusion of liquid in the upper fiber web is blocked, and the infiltration of liquid in the upper fiber web is ensured.

[0031] The core - sheath structured high - and low - melting - point fibers of the lower fiber web are composed of eccentric fibers and hollow fibers. The two types of fibers are evenly mixed and carded. The eccentric fibers form three - dimensional natural curls, which is beneficial to providing the three - dimensional thickness of the product and reducing re - wetting. The hollow fibers have the characteristics of moisture absorption, light weight and softness, which is beneficial to liquid conduction. The ratio of eccentric fibers to hollow fibers is 1:0.5 - 2. For example: 1:0.4; 1:0.5; 1:0.7; 1:0.9; 1:1.5; 1:2; 1:2.5; 1:3; 1:4; 1:5, etc.

[0032] For the upper fiber web, the contact angle θ1 between the liquid droplet with wettability of surface energy and the solid surface, and the equivalent radius r1 of the voids between fibers; for the lower fiber web, the contact angle θ2 between the liquid droplet with wettability of surface energy and the solid surface, and the equivalent radius r2 of the voids between fibers satisfy θ2 < θ1 < 90° and cosθ1 / r1 < cosθ2 / r2. During the production process, by controlling the hydrophilic strength of the fiber oil agent, such as the EO number of polyethylene oxide ether in the oil agent, the regulation of the contact angle θ between the liquid droplet and the solid surface is achieved; by adjusting the process and fiber fineness during the fiber carding process, the equivalent radius r of the voids between fibers is controlled.

[0033] The fiber randomness of the upper fiber web > the fiber randomness of the lower fiber web. The hot air penetrates from the lower fiber web to the upper fiber web to reinforce the double - layer fiber web. The low fiber randomness of the lower fiber web improves the longitudinal liquid diversion; the high fiber randomness of the upper fiber web reduces the difference in longitudinal and transverse strengths of the upper fiber web and improves the abrasion resistance of the upper layer (not easy to fluff, soft).

[0034] As a further improvement of the present invention, TiO2 is added to PBAT or PBS. Tri - n - butyl acetylcitrate, TiO2 and PBAT or PBS are extruded and pelletized by a screw extruder to prepare PBAT or PBS filled with TiO2. Due to TiO 22 and the resin having different refractive indices to light, it has the effect of whitening the fibers. Using the principle of color superposition, the fading of red or dark - red menstrual blood is achieved.

[0035] This invention utilizes the softness, rigidity, and melting point characteristics of PBAT (PBS) and high- and low-melting-point PLA fibers to prepare a unidirectional, biodegradable hot-air nonwoven fabric composed of an upper layer of soft, fine-denier fiber web and a lower layer of rigid, coarse-denier fiber web. The relationship between the surface energy and capillary properties of the upper and lower fiber layers is established to achieve rapid liquid penetration, while the three-dimensional, fluffy structure composed of the lower layer of eccentric and hollow fibers prevents liquid re-wetting. Simultaneously, techniques are employed to block liquid diffusion in the upper fiber web and to lighten the color of the whitening fibers, resulting in a nonwoven fabric characterized by softness, minimal surface diffusion, effective concealment of menstrual blood, rapid liquid penetration, and low re-wetting.

[0036] According to GB / T 24218.2-2009 Textiles - Nonwovens - Test Methods - Part 2: Determination of Thickness, GB / T 24218.13-2010 Textiles - Nonwovens - Test Methods - Part 13: Determination of Liquid Penetration Time, and GB / T 24218.14-2010 Textiles - Nonwovens - Test Methods - Part 14: Determination of Moisture Reabsorption of Covering Materials, 30gsm nonwoven fabric (both upper and lower fiber webs are 15gsm) was tested to characterize its bulkiness, liquid penetration time, and moisture reabsorption.

[0037]

[0038] Using 30gsm nonwoven fabric (both upper and lower fiber webs are 15gsm) as the surface layer material of the sanitary napkin, the performance of the sanitary napkin was tested according to the following method:

[0039] 1. Adjust the temperature of the pig's blood to 23±1℃;

[0040] 2. Lay the sanitary napkin flat on the table, measure the longitudinal center as the dispensing point, and mark it.

[0041] 3. Use a pipette to add 5ml of pig blood to the liquid addition point, and start timing the time required for the pig blood to be completely absorbed on the surface (i.e., absorption time in seconds);

[0042] 4. After 5 minutes, cover the liquid addition point with a known weight of filter paper (110 mm in diameter) and place a 2.5 kg block (110 mm in diameter) on top. After 2 minutes, weigh the filter paper W2 and calculate the increase in weight of the filter paper (i.e., the amount of backflow W).

[0043] 5. Repeat step 3 after 1 minute, repeating twice, for a total of 3 additions;

[0044] 6. Test the diffusion length between the surface layer and the core, and observe the color of the surface layer.

[0045]

[0046] Example 2

[0047] A disposable hygiene product includes a top layer, an absorbent core, and a breathable bottom membrane; the top layer is made of a directional moisture-wicking nonwoven fabric as described in the above embodiment.

[0048] Example 3

[0049] Based on the above embodiment 2, the absorbent core is a multi-layer absorbent core.

[0050] The multi-layer absorbent core includes an upper spacer fabric absorbent layer and a lower reservoir layer composed of highly absorbent resin and non-woven material.

[0051] The absorbent layer of the spacer fabric is composed of upper textile yarns, lower textile yarns, and support textile yarns.

[0052] The upper textile yarn is polyester yarn. In order to improve the liquid wetting effect, the polyester yarn is treated with sodium hydroxide to open some of the ester bonds in the polyester to achieve a hydrophilic effect. Its moisture regain is controlled at 0.4% to 2.0%.

[0053] The lower layer of textile yarn is polyester, viscose, cotton, or a combination thereof, and its moisture regain is controlled at ≥3%.

[0054] The support layer textile yarn is polyester yarn or a combination of polyester yarn and polyester monofilament. In order to improve the liquid wetting effect, it is hydrophilic after being modified with polyether, epoxy polyether or amino polyether, and its moisture regain is controlled at 0.8% to 4.0%.

[0055] The aforementioned textile yarns are yarns with a diameter of 35-500um; each yarn consists of 7-30 fibers, each fiber being approximately 5-35um.

[0056] Anticoagulant, hydrophilic additives and PET chips are mixed, melt co-extruded by twin-screw extruder, water cooled, pelletized and dried to obtain hydrophilic anticoagulant PET masterbatch, which is then spun to prepare polyester yarn.

[0057] The anticoagulant is sodium citrate or disodium EDTA, and the dosage is generally 1%-5% of the total weight.

[0058] Moisture regain: Upper layer textile yarn < Support layer textile yarn < Lower layer textile yarn;

[0059] The diameter of a single polyester fiber is: the diameter of the supporting layer textile fiber is less than that of the upper layer textile fiber; this ensures that the liquid seeps downwards while minimizing the diffusion of the liquid in the upper layer.

[0060] The supporting layer of polyester single fibers is an irregularly shaped fiber, such as cross-shaped, Y-shaped, T-shaped or W-shaped, with grooves on the fiber surface to prevent the capillary channels between fibers from being blocked by coagulated blood, thus losing the capillary effect and preventing blood from penetrating downwards. This results in repeated use, where the liquid spreads in the upper layer, affecting dryness.

[0061] The synergistic effect of anticoagulant masterbatch and grooved irregular fibers slows down capillary blockage caused by blood coagulation on the fiber surface.

[0062] Furthermore, the support layer can be a composition of polyester yarn and polyester monofilament, with the ratio of polyester monofilament fineness to polyester yarn fineness being 0.5 to 2:1, for example, 0.5:1, 1:1, 1.5:1, or 2:1. The polyester monofilaments and polyester yarn are arranged at regular intervals, with the polyester monofilaments providing a supportive elastic structure and the polyester yarn promoting liquid penetration.

[0063] The liquid storage layer has a four-layer structure: the first layer is a non-woven material; the second layer is a highly absorbent resin prepared by a low-temperature synthesis method of prior polymerization and cross-linking followed by neutralization, which has a rough surface and constructs multiple blood flow channels to prevent hemoglobin blockage; the third layer is a highly absorbent resin prepared by a high-temperature synthesis method of prior neutralization followed by polymerization and cross-linking, which has high absorption capacity; and the fourth layer is a non-woven material.

[0064] According to GB / T 10807-2006 "Determination of Hardness of Flexible Foam Polymer Materials (Indentation Method)", the flat compression performance of the spacer fabric was tested to characterize its elasticity. The monofilament + yarn solution significantly improved the stress compared to the yarn, approaching the effect of using monofilament as a support layer, which can effectively improve the elasticity of the material.

[0065] Test Method (1):

[0066] 1. Adjust the temperature of the pig's blood to 23±1℃;

[0067] 2. Lay the sanitary napkin flat on the table, measure the longitudinal center as the dispensing point, and mark it.

[0068] 3. Use a pipette to add 5ml of pig blood to the liquid addition point, and start timing the time required for the pig blood to be completely absorbed on the surface (i.e., absorption time in seconds);

[0069] 4. After 5 minutes, cover the liquid addition point with a known weight of filter paper (110 mm in diameter) and place a 2.5 kg block (110 mm in diameter) on top. After 2 minutes, weigh the filter paper W2 and calculate the increase in weight of the filter paper (i.e., the amount of backflow W).

[0070] 5. Repeat step 3 after 1 minute, repeating twice, for a total of 3 additions.

[0071]

[0072]

[0073] Test Method (II)

[0074] 1. Adjust the temperature of the pig's blood to 23±1℃;

[0075] 2. Lay the sanitary napkin flat on the table, measure the longitudinal center as the dispensing point, and mark it.

[0076] 3. Use a pipette to add 5ml of pig blood to the liquid addition point, and start timing the time required for the pig blood to be completely absorbed on the surface (i.e., absorption time in seconds);

[0077] 4. After 5 minutes, cover the liquid addition point with a known weight of filter paper (110 mm in diameter) and place a 2.5 kg block (110 mm in diameter) on top. After 2 minutes, weigh the filter paper W2 and calculate the increase in weight of the filter paper (i.e., the amount of backflow W).

[0078] 5. After 30 minutes (to allow the blood to clot), repeat step 3 again, repeating twice, for a total of 3 additions.

[0079] Study the effects of different yarn treatment methods on absorption and rewetting.

[0080]

[0081] Study on the effects of different SAP combinations on absorption and re-osmosis

[0082]

[0083] Example 4

[0084] Based on the above embodiments, the liquid storage layer has a five-layer structure: the first layer is a non-woven material, the second layer is a plant-based composite core, the third layer is a non-woven material, the fourth layer is a highly absorbent resin prepared by a low-temperature synthesis method after polymerization and cross-linking, which has a rough surface, constructs multiple blood flow channels, and prevents hemoglobin blockage, and the fifth layer is a non-woven material.

[0085] The plant-based absorbent core consists of three layers: the upper and lower layers are composite non-woven absorbent covering layers made of seaweed fiber and acidic wood ash; the middle absorbent layer is a liquid storage layer composed of acidic wood ash absorbent material and fluffy cotton. The preparation method of the plant-based composite core includes the following steps:

[0086] 1) Preparation of acidic wood ash; The method for preparing acidic wood ash includes: dissolving wood ash powder in hydrochloric acid solution, with a hydrochloric acid content of 1%-10% and a mass ratio of hydrochloric acid to wood ash of 10:1, to achieve an acid-base neutralization reaction and adjust the acidity or alkalinity of the wood ash; stirring the reaction with a stirrer for 1-2 hours; drying at a temperature controlled at 40-50℃; and sieving through a 120-mesh sieve to obtain acidic wood ash particles;

[0087] 2) Preparation of modified seaweed fiber; The preparation method of the modified seaweed fiber includes: using seaweed fiber as a substrate and deionized aqueous solution as a solvent; dispersing the seaweed fiber in a pulping machine, adding acidic wood ash, and stirring at high speed and low temperature with a content of 0.1-1% and a temperature of 30-40℃ for 3-6 minutes to fully mix the seaweed fiber and wood ash.

[0088] After the seaweed fiber was rapidly stirred and dispersed, it was mixed with acidic wood ash. Under acidic conditions, the eggshell structure of the seaweed fiber was destroyed, and the crystalline region was disrupted. At the same time, the calcium alginate in the seaweed fiber and the wood ash contained a variety of trace elements. Among them, potassium ions and sodium ions underwent an exchange reaction to form calcium alginate / potassium and calcium alginate / sodium hydrogel fibers, which promoted slight swelling of the fibers, reduced cross-linking points, weakened the interaction force, enhanced the water-accessible area, and improved hygroscopicity and tensile strength.

[0089] 3) Preparation of composite nonwoven fabric; The preparation method of composite nonwoven fabric includes the following steps: laying modified seaweed fiber into a web; spreading acidic wood ash between two layers of seaweed fiber web; combining the two fiber webs after spreading acidic wood ash, using gelled seaweed fiber to coat and bond the acidic wood ash, using needle punching process to slowly reinforce, pressing into sheets, dehydrating and drying, finishing and shaping to make composite nonwoven fabric;

[0090] The nonwoven fabric made of seaweed fiber and wood ash has increased absorption capacity. After absorbing moisture, water molecules and fiber molecules form a three-dimensional network structure through hydrogen bonding, thus transforming into a gel and enhancing the tensile strength of the nonwoven fabric in a wet state. The wood ash particles improve the clogging of the seaweed fiber moisture-absorbing paste gel. After the seaweed fiber absorbs blood quickly, it gels and becomes more skin-friendly and conforms better to the body. The wood ash absorbs blood and seeps downward, improving backflow and enhancing dryness.

[0091] 4) Preparation of plant-based liquid reservoir layer; The plant-based liquid reservoir layer is composed of acidic wood ash and fluffy cotton as a fixing layer; The fluffy cotton is divided into multiple layers; Acidic wood ash is spread on each layer of fluffy cotton;

[0092] Wood ash is the ash powder produced by burning various medicinal plants. It contains the most potassium, followed by phosphorus, and also trace elements such as calcium, magnesium, silicon, iron, and zinc. It has mild properties, dispels cold and reduces swelling, and has antibacterial and bacteriostatic effects, which can effectively promote women's health.

[0093] Using acidic wood ash as the absorbent substrate, absorbent materials are prepared by distributing acidic wood ash in different proportions on fluffy non-woven fabric to replace water-absorbing resin. While ensuring absorption performance, the dryness and humidity can be adjusted to reduce dampness, while also increasing natural antibacterial, cold-dispelling, swelling-reducing, and odor-removing effects.

[0094] The fixed layer of fluffy cotton is a three-dimensional mesh structure with many pores. Acidic wood ash is distributed and spread in different proportions and positions on the top layer of fluffy cotton in a candy-like spreading pattern with a ratio of 3:1. The middle layer of acidic wood ash is concentrated and spread from the center to both sides. At the same time, the fluffy cotton in the middle position is made into a cone-shaped opening pattern, and the wood ash layer is spread in the lower middle to prepare an absorbent layer.

[0095] 5) A layer of composite nonwoven fabric is placed on the top and bottom of the prepared liquid storage layer to cover the liquid storage layer.

[0096] During the core composite process, the upper and lower layers of seaweed composite nonwoven fabric are wrapped around the middle absorbent layer. At the same time, under the alkaline conditions of wood ash, the seaweed fibers and cotton fibers exhibit gelation properties. Wood ash is used as an adhesive to bond the wrapping layer and the absorbent layer, thus preparing the composite core.

[0097] A plant-based composite core is made using seaweed fiber and natural plant materials such as wood ash as the base material, ensuring that the materials are natural, safe, and biodegradable. The various trace elements in wood ash can gel with seaweed fiber to prepare the upper and lower base fabrics. At the same time, wood ash is used to regulate the dryness and moisture, improve the backflow of the base fabric, and enhance dryness. Fluffy cotton and wood ash are used as the absorbent layer. Wood ash, as a plant ash powder, can adjust the dryness and moisture while ensuring absorption performance, reducing dampness, and adding natural antibacterial, cold-dispelling, swelling-reducing, and odor-removing effects. The prepared composite core is not easy to break or delaminate, and it also adds antibacterial and odor-removing functions, reducing the occurrence of inflammation.

[0098] Example 5

[0099] As an improvement to the above embodiment, the bottom film is an antibacterial, deodorizing and breathable bottom film, which is made by three-layer co-extrusion and stretching of a first film layer, a second film layer and a third film layer;

[0100] The first thin film layer is provided with an antibacterial porous material and / or a deodorizing porous material of a first diameter;

[0101] The second film layer is provided with a deodorizing porous material and / or an antibacterial porous material of a second diameter;

[0102] The third film layer material contains a third filler with a third diameter;

[0103] in,

[0104] First diameter > Second diameter > Third diameter;

[0105] In co-extruded films, the thickness of the first film layer > the thickness of the second film layer > the thickness of the third film layer;

[0106] The weight ratio of the first filler to the first resin raw material in the first film layer raw material is 1.5-2.5:1;

[0107] The weight ratio of the second filler to the second resin in the second film layer raw material is 1-2:1;

[0108] The weight ratio of the third filler to the second resin raw material in the third film layer raw material is 0.8-1:1.

[0109] By using porous materials instead of traditional calcium carbonate, the material is lightweight and has numerous breathable channels, which improves air permeability. The porous material is modified with deodorizing functional groups to eliminate various odors; surface activation treatment gives the porous particles good dispersibility and hydrophobicity; the addition of antibacterial agents inhibits bacterial growth during use, further improving the deodorizing effect. In summary, this invention is a lightweight, highly breathable, antibacterial, and deodorizing breathable bottom membrane for hygiene products.

[0110] Deodorization modification of porous materials (average particle size 1-5 μm) includes:

[0111] 1) Ionic liquid / acidification modification (containing acidic components such as amino acids, sulfonic acid, carboxylic acid, and sulfuric acid)

[0112] 2) Metal ion supported (Fe, Mn, Zn, Cu, Ag, Na, etc.)

[0113] For example, the impregnation method is used to load metal ions onto zeolite materials. The impregnation method involves immersing a solid powder or a pre-formed solid (carrier or catalyst containing the host) of a specific shape and size in a solution of a soluble compound containing active components (main and co-catalyst components). After contact for a certain period, the residual liquid is separated, and the active components adhere to the solid in the form of ions or compounds. This method is mainly used to prepare Fe, Mn, Cu, Ag, Ce, Al, La, Zn, and Na-loaded zeolites. The main steps are impregnation-drying-calcination. Among these, Fe, Mn, and Na-loaded zeolites show better adsorption effects for ammonia nitrogen, exhibiting ion exchange activity.

[0114] For example, the sol-gel method can be used to load metal ions onto zeolite materials. The sol-gel method uses compounds containing highly chemically active components as precursors. These raw materials are uniformly mixed in the liquid phase and undergo hydrolysis and condensation reactions to form a stable, transparent sol system in solution. The sol then ages and slowly polymerizes between the particles, forming a three-dimensional network structure called a gel. The spaces between the gel networks are filled with solvent that has lost its flowability, thus forming a gel. This method is mainly used to prepare Ti-loaded zeolites, using natural zeolites. For example, antibacterial porous materials can also be prepared by loading silver, zinc, or nano-silver into porous materials using the sol-gel method.

[0115] 3) Add 1-5 parts of deodorizing agent: such as acidic materials, zinc ricinoleate, plant extracts, etc.

[0116] Plant extracts contain many bioactive components, including flavonoids, phenolic acids, and alkaloids. The ortho- and meta-position active phenolic hydroxyl groups can undergo condensation and complexation reactions with the -SH and -NH2 groups of ammonia and hydrogen sulfide gases. Therefore, plant extracts containing flavonoids and phenolic hydroxyl groups have certain deodorizing properties against ammonia and hydrogen sulfide gases.

[0117] Lemon extract – active ingredients include: polyphenols, phenolic glycosides, alkaloids, etc.

[0118] Tea extracts – active ingredients include: polyphenols, catechins, etc.

[0119] Eucalyptus oil – active ingredients include: polyphenols, catechins, etc.

[0120] The activation treatment of porous materials in this invention can be carried out by various methods, including metal loading modification, metal oxide modification of compounds, surface modification, surfactant modification, acidification modification, adsorbent composite modification, ultrasonic / microwave modification, etc.

[0121] Examples of deodorization and activation using porous materials:

[0122] Step ① Powder Modification: Impregnate 100 parts of silica in 150 parts of a 10wt% dilute hydrochloric acid solution of 2-amino-3-p-hydroxyphenylpropionic acid, mix and stir for 30 minutes, then filter and wash with deionized water. Add 10 parts of Zn(NO3)·6H2O, stir for 10 minutes, and then filter. Add an appropriate amount of 10 parts of AgNO3, filter, and dry at 110℃ for 12 hours, controlling the moisture content to below 600ppm. Remove, grind, sieve, classify, and store in sealed bags for later use.

[0123] The present invention has been described in detail above, but it is not limited to the embodiments described above. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the invention. Many other changes and modifications made without departing from the concept and scope of the invention should be considered within the scope of protection of the present invention.

[0124] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0125] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A directional moisture-wicking nonwoven fabric, characterized in that, The nonwoven fabric is made of a double-layer fiber web reinforced with fibers; wherein, The upper fiber web is a bicomponent fiber with a core-sheath structure, consisting of a PBAT or PBS sheath and a PLA core, with a fiber denier of 0.6D to 1.5D. The lower fiber web is composed of high- and low-melting-point fibers with a sheath-core structure consisting of a low-melting-point PLA sheath and a high-melting-point PLA core, with a fiber denier of 1.5D to 6.0D. The core-sheath structure of the upper fiber web consists of two types of fibers: hydrophobic and hydrophilic. The two types of fibers are uniformly mixed and combed, with the ratio of hydrophobic fiber to hydrophilic fiber being 1:0.2~5. The core-sheath structure of the lower fiber web consists of high and low melting point fibers composed of eccentric fibers and hollow fibers, which are uniformly mixed and combed; the ratio of eccentric fibers to hollow fibers is 1:0.5~2. The contact angle θ1 between a wettable droplet on the surface of the upper fiber web and the solid surface, and the equivalent radius r1 of the inter-fiber void; the contact angle θ2 between a wettable droplet on the surface of the lower fiber web and the solid surface, and the equivalent radius r2 of the inter-fiber void, satisfying θ2 < θ1 < 90° and cosθ1 / r1 <cosθ2 / r2; The fiber disorder of the upper fiber web is greater than that of the lower fiber web. Hot air penetrates from the lower fiber web to the upper fiber web to reinforce the double-layer fiber web.

2. The directional moisture-wicking nonwoven fabric as described in claim 1, characterized in that, TiO2 is added to the PBAT or PBS.

3. A disposable sanitary product made from the directional moisture-wicking nonwoven fabric as described in claim 1.

4. A method for preparing a directional moisture-wicking nonwoven fabric as described in claim 1, characterized in that, The method includes the following steps: Prepare the upper layer fiber; the upper layer fiber is a bicomponent fiber with a core-sheath structure consisting of a PBAT or PBS sheath and a PLA core, with a fiber denier of 0.6D~1.5D; Prepare the lower layer fiber; the lower layer fiber is a high-low melting point fiber with a sheath-core structure composed of a low melting point PLA sheath layer and a high melting point PLA core layer, with a fiber denier of 1.5D~6.0D; The core-sheath structure bicomponent fiber is prepared into two types of fibers: hydrophobic and hydrophilic. The two types of fibers are uniformly mixed and combed to prepare an upper fiber web, wherein the ratio of hydrophobic fiber to hydrophilic fiber in the upper fiber web is 1:0.2~5. High and low melting point fibers with a core-sheath structure are prepared into eccentric fibers and hollow fibers. The two types of fibers are uniformly mixed and combed to prepare a lower fiber web. The ratio of eccentric fibers to hollow fibers in the lower fiber web is 1:0.5~2. Hot air penetrates from the lower fiber web to the upper fiber web to reinforce the double-layer fiber web, wherein the fiber disorder of the upper fiber web is greater than that of the lower fiber web; The contact angle θ1 between the wettable droplet on the surface of the upper fiber web and the solid surface, and the equivalent radius r1 of the inter-fiber gap; the contact angle θ2 between the wettable droplet on the surface of the lower fiber web and the solid surface, and the equivalent radius r2 of the inter-fiber gap, satisfy θ2 < θ1 < 90° and cosθ1 / r1 <cosθ2 / r2。 5. The method for preparing the directional moisture-wicking nonwoven fabric as described in claim 4, characterized in that, TiO2 is added to the PBAT or PBS.

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