Spunbond nonwoven fabric with long-lasting one-way moisture transfer and smooth touch and its preparation method

Abstract

This application relates to a spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking properties, and its preparation method. It belongs to the technical field of unidirectional moisture-wicking spunbond nonwoven fabrics. The fabric includes: a skin-adhering inner layer, an intermediate layer, and an evaporating outer layer. The skin-adhering inner layer comprises 98.5-99.8% matrix resin and 0.2-1.5% first masterbatch. The intermediate layer comprises 96-98.5% matrix resin, 0.5-1% second masterbatch, and 1-3% graft-modified resin. The total mass of the raw material components in the evaporating outer layer is 100%. The evaporating outer layer comprises 95-98% matrix resin and 2-5% second masterbatch. The first masterbatch is a fluorinated compound, and the second masterbatch is a mixture of nano-titanium dioxide and a polyoxyethylene-polypropylene-polyoxyethylene triblock copolymer. The graft-modified resin is a mixture of polyethylene grafted with maleic anhydride and an ionomer. The spunbond nonwoven fabric prepared by this application can simultaneously achieve smoothness, adhesion, and long-lasting unidirectional moisture wicking properties.

Description

Technical Field

[0001] This application relates to the field of unidirectional moisture-wicking spunbond nonwoven fabric technology, and in particular to a spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking and its preparation method. Background Technology

[0002] One-way moisture-wicking nonwoven fabrics are widely used in medical and hygiene fields (such as surgical gowns and dressings), personal care (such as the skin-contact layer of diapers and sanitary napkins), and high-end sportswear. Their core principle is to utilize capillary pressure difference to rapidly draw sweat or moisture from the skin-contact side to the evaporating outer layer, keeping the skin-contact surface dry. To improve user comfort, manufacturers of one-way moisture-wicking nonwoven fabrics often add slip-resistant substances to the raw materials of the inner skin-contact layer. However, the surface slippage (low surface energy) of the substance and interlayer adhesion are thermodynamically mutually exclusive. In multilayer nonwoven fabric composite processes, once a substance with excellent hydrophobic and slip-resistant properties is added to the inner skin-contact layer, these low surface energy substances will inevitably accumulate at the interface between the inner skin-contact layer and the evaporating outer layer. This forms a "lubricating isolation film," making it impossible for the layers to bond during hot-pressing and easily leading to interlayer delamination. To prevent adhesion, existing technologies are forced to use adhesives, but this clogs the moisture-wicking pores.

[0003] In addition, the preparation of unidirectional moisture-wicking nonwoven fabrics in the existing technology still has the following problems: hydrophilic modification is mostly carried out by post-treatment coating process (such as roller coating, spraying). This process not only increases production energy consumption and drying process, but also makes it easy for hydrophilic agents to penetrate into the inner layer of the skin and destroy the moisture wicking gradient. More seriously, the surface coating has poor water resistance and durability and is prone to failure after friction or washing. Summary of the Invention

[0004] The purpose of this application is to address the shortcomings of existing technologies in preparing unidirectional moisture-wicking nonwoven fabrics, which make it difficult to simultaneously achieve a smooth feel, strong interlayer adhesion, and long-term stable moisture-wicking performance. Therefore, this application proposes a spunbond nonwoven fabric with a smooth feel and long-term unidirectional moisture wicking and its preparation method.

[0005] In the first aspect, the spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking provided by this application adopts the following technical solution: it includes a skin-adhering inner layer, an intermediate layer and an evaporating outer layer. Based on the total mass of the raw material components of the skin-adhering inner layer as 100%, the skin-adhering inner layer includes 98.5~99.8% matrix resin and 0.2~1.5% first masterbatch. Based on the total mass of the raw material components of the intermediate layer as 100%, the intermediate layer comprises 96-98.5% matrix resin, 0.5-1% second masterbatch and 1-3% grafted modified resin. Based on the total mass of the raw material components of the evaporation outer layer being 100%, the evaporation outer layer comprises 95-98% matrix resin and 2-5% second masterbatch; The first masterbatch is a fluorinated compound, the second masterbatch is a mixture of nano-titanium dioxide and polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (PEO-PPO-PEO), and the grafted modified resin is a mixture of polyethylene grafted with maleic anhydride and ionomer.

[0006] Through the above technical solution, the spunbond nonwoven fabric of this application has 0.2-1.5% of a first masterbatch (fluorinated compound, strongly hydrophobic) added to the inner skin-contact layer, 0.5-1% of a second masterbatch (micro-hydrophilic) added to the middle layer, and 2-5% of a second masterbatch (strongly hydrophilic) added to the outer evaporation layer, establishing a continuously increasing surface energy gradient. This promotes moisture to pass through the hydrophobic inner layer, cross the middle layer, and finally lock in the strongly hydrophilic outer layer, thereby giving the spunbond nonwoven fabric unidirectional moisture-wicking properties. At the same time, the ionomer in the middle layer, utilizing its dynamically reversible ion clusters, can penetrate the low-temperature inner layer instantaneously during the high temperature of thermal bonding. The surface energy interface generates strong "ion-dipole interaction" with the polar segments in the inner fluorinated components or the polar groups in the matrix resin. At the same time, it is combined with the flexible chain segment entanglement provided by polyethylene grafted maleic anhydride. The middle layer acts as a "thermodynamic bonding membrane". This compound not only provides the possibility of interfacial chemical bonding, but also absorbs interlayer shear stress through elastomer. The synergistic effect of polyethylene grafted maleic anhydride and ionomer makes it possible to effectively improve the interlayer bonding strength even in the presence of slip components, so that the prepared spunbond nonwoven fabric can simultaneously take into account both "slip" and "adhesion" properties. Due to its relatively moderate molecular weight and amphiphilic properties, PEO-PPO-PEO can more rapidly segregate and migrate to the fiber surface during the spinning and cooling stage, giving the nonwoven fabric extremely high hydrophilic activity and instantaneous suction force in the early stage of film formation. Nano titanium dioxide, due to its better compatibility with the polyester hard segment and the matrix resin, exhibits a stronger "matrix anchoring effect", which allows the hydrophilic components to remain on the fiber surface after repeated wetting, ensuring the long-term stability of the unidirectional moisture-wicking performance of the nonwoven fabric under complex usage environments (such as repeated urination or heavy sweating).

[0007] Optionally, the first masterbatch is a mixture of perfluoroalkyl (meth)acrylate copolymer and polytetrafluoroethylene micro powder in a mass ratio of 3 to 5:1.

[0008] The above technical solution, through the synergistic effect of perfluoroalkyl (meth)acrylate copolymer and polytetrafluoroethylene micropowder in a specific ratio, utilizes the excellent melt migration and film-forming properties of perfluoroacrylate polymer to solve the problems of dispersion stability and interfacial bonding force of polytetrafluoroethylene micropowder in the spinning process. Thus, while giving the inner layer of nonwoven fabric an extremely low friction feel, it ensures the wear resistance and long-lasting effect of the smooth function.

[0009] Optionally, the mass ratio of nano-titanium dioxide to poly(ethylene oxide-poly(propylene oxide-poly(ethylene oxide)) triblock copolymer is 3 to 6:1.

[0010] Through the above technical solution, although nano-titanium dioxide possesses permanent surface hydroxyl hydrophilicity, its large specific surface area easily leads to severe agglomeration in the polymer melt. This not only results in the loss of hydrophilicity but also increases the likelihood of fiber breakage during spinning. An appropriate amount of PEO-PPO-PEO block copolymer, with its flexible polyether segments (especially PEO segments rich in ether oxygen bonds), can form strong hydrogen bond interactions with the hydroxyl groups on the surface of nano-titanium dioxide. This "in-situ coating" of the polymer chain provides excellent steric hindrance, preventing nanoparticle agglomeration and ensuring smooth spinning of the components and stable fiber mechanical properties.

[0011] Optionally, the ionic polymer is an ethylene-methacrylic acid copolymer containing sodium ions, and the mass ratio of polyethylene grafted with maleic anhydride to the ethylene-methacrylic acid copolymer containing sodium ions is 1~2:1.

[0012] With the above technical solutions, when the ratio is less than 1:1, the overall flexibility of the interlayer decreases significantly. When the fabric is torn or rubbed externally, the stress cannot be effectively dissipated, which may lead to brittle fracture of the interlayer itself (cohesive failure), still exhibiting interlayer adhesion. When the ratio is greater than 2:1, the concentration of ionic polymers at the low surface energy interface in the interlayer is excessively diluted. During the brief millisecond-level hot rolling contact time, it is impossible to provide a sufficient density of ionic bonding points at the bonding interface, resulting in an inability to effectively counteract the interfacial slippage effect brought about by the fluorinated components in the inner layer, and a significant decrease in hot-pressing adhesion strength.

[0013] Further optionally, the grafting rate of the polyethylene grafted with maleic anhydride is 8-12%.

[0014] Through the above technical solution, the appropriate distribution of anhydride groups will not interfere with the migration of metal ions in the ionomer due to the charge shielding effect, and can also assist the rearrangement of ion clusters at the interface through polar induction. This synergistic effect constructs a dynamic bonding network at the microscopic level, giving the nonwoven fabric excellent interlayer bonding strength.

[0015] Alternatively, the melt index ratio of the ionomer to the matrix resin is 0.8 to 1.2:1.

[0016] With the above technical solution, when the ratio is less than 0.8, the melt viscosity of the ionomer is significantly higher than that of the matrix resin. During the short hot rolling composite process, when the matrix resin is already in a suitable viscous flow state, the ionomer often still exhibits high viscous resistance, making it difficult for it to effectively migrate and wet the polar sites of adjacent layers (especially the inner layer with hydrophobic properties), which greatly reduces the "electrostatic anchoring" effect. When the ratio is higher than 1.2, the viscosity of the ionomer is much lower than that of the matrix resin. This may cause the excessively diluted ionomer to form discontinuous defect points on the fiber surface, which can easily lead to "flying" or "dripping" during the spinning process. It may also block the capillary pores of the nonwoven fabric due to excessive flow, thus affecting the overall mechanical strength and moisture-wicking properties.

[0017] Optionally, the matrix resin is selected from one or more of thermoplastic polyester elastomer (TPEE), polyester (PET), polypropylene (PP), and polylactic acid (PLA). More preferably, it is polypropylene.

[0018] Secondly, this application provides a method for preparing the above-described spunbond nonwoven fabric, the method comprising the following steps: S1. Weigh the raw material components of the skin-adhering inner layer, the middle layer, and the evaporation outer layer according to the formula. Place the raw material components of the skin-adhering inner layer in the screw extruder of the first die, the raw material components of the middle layer in the screw extruder of the second die, and the raw material components of the evaporation outer layer in the screw extruder of the third die for extrusion melting and filtration. Then, transport the filtered products to the spinneret corresponding to each die for confluence spinning. Then, separate the fibers and lay them into webs. From bottom to top, the average fiber fineness of the inner layer fiber web, the middle layer fiber web, and the evaporation outer layer fiber web decreases sequentially. S2. The inner skin-adhesive fiber web, the middle fiber web, and the outer evaporation fiber web are pre-consolidated, main-consolidated, cooled and shaped, and then wound up to obtain the spunbond nonwoven fabric.

[0019] Optionally, the average fiber fineness of the inner skin-adhering fiber mesh is 3~3.5D, the average fiber fineness of the middle layer fiber mesh is 1.8~2.5D, and the average fiber fineness of the outer evaporation fiber mesh is 0.7~1.5D.

[0020] Through the above technical solution, the outer evaporation layer uses ultra-fine fibers (0.7~1.5D), not only to provide maximum capillary suction, but also because the ultra-fine fibers give this layer the largest specific surface area. When water is "pumped" to the outer layer, it can quickly spread into an extremely thin liquid film on the surface of the numerous fine fibers. The huge liquid-gas contact area greatly increases the evaporation rate of water. At the same time, the inner skin-adhering layer uses coarser fibers (3~3.5D), reducing the actual contact area between a single fiber and the skin. Combined with the low-friction properties of the fluorine-containing component, This further amplifies the "non-sticky, highly smooth" feel of the inner layer; combined with the unique "ion polymer and grafted elastomer" compound in the middle layer, the moderate average fiber fineness of 1.8~2.5D ensures that the middle layer melt can effectively penetrate downwards to wet the robust inner layer fibers, and can also achieve sufficient physical entanglement with the dense, extremely fine outer layer fibers. It is probably due to this smooth transition of geometric dimensions that the interfacial stress concentration caused by excessive differences in the pore size of coarse and fine fibers is effectively avoided, further consolidating the interfacial resistance to interlaminar delamination from a physical and mechanical perspective.

[0021] Optionally, the first die head has a spinneret orifice diameter of 0.5~0.6 mm, a spinneret orifice density of 3500~4500 orifices / meter, a metering pump speed of 30~40 rpm, a suction pressure under the mesh of 1000~1500 Pa, and a cold air temperature of 15~20 ℃; the second die head has a spinneret orifice diameter of 0.4~0.5 mm, a spinneret orifice density of 4500~5500 orifices / meter, a metering pump speed of 20~28 rpm, a suction pressure under the mesh of 1800~2500 Pa, and a cold air temperature of 15~20 ℃; the third die head has a spinneret orifice diameter of 0.3~0.4 mm, a spinneret orifice density of 5500~7000 orifices / meter, a metering pump speed of 12~18 rpm, a suction pressure under the mesh of 3000~4500 Pa, and a cold air temperature of 8~12 ℃.

[0022] In a specific implementation, the screw extruder temperature corresponding to the first die, the second die, and the third die is 190~250 ℃, the spinning box temperature is 230~280 ℃, the hot rolling temperature is 150~175 ℃, and the linear pressure is 60~80 N / mm.

[0023] In this paper, pre-consolidation, primary consolidation, cooling and shaping, and winding are all routine operations in this field and will not be elaborated on here.

[0024] In a specific embodiment, the difference in web laying angle between the inner skin-adhering fiber web and the middle fiber web, and between the middle fiber web and the outer evaporation fiber web, is controlled within 10°~30°.

[0025] A three-dimensional oblique fiber network was constructed between the layers by means of an angle difference of 10° to 30°. This physical "geometric interlocking" greatly increased the density of fiber contact points, providing a large number of microscopic attachment points for the intermediate layer "ion exchange resin", forming a composite consolidation effect similar to "physical fastening + chemical zipper".

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. The spunbond nonwoven fabric described in this application establishes a continuously increasing surface energy gradient among the skin-adhering inner layer, the intermediate layer, and the evaporating outer layer, thereby giving the spunbond nonwoven fabric unidirectional moisture-wicking properties. At the same time, a mixture of polyethylene grafted maleic anhydride and ionomer is added to the intermediate layer. By utilizing the synergistic effect of polyethylene grafted maleic anhydride and ionomer, the interlayer bonding strength can still be effectively improved even in the presence of slip-resistant components, so that the prepared spunbond nonwoven fabric can simultaneously take into account both "slip-resistant" and "adhesive" properties. 2. The specific components contained in the inner, middle and outer layers of the skin-adhesive fabric are combined with the average fiber fineness of each layer to further amplify the smooth feel of the inner layer, while further consolidating the anti-delamination of the spunbond nonwoven fabric layers from a physical and mechanical perspective. Detailed Implementation

[0027] The present application will be further described in detail below with reference to specific embodiments.

[0028] It should be noted that the specific embodiments of this application are intended to elaborate on the technical solutions in the claims. Terms such as "first" and "second" used herein are only used to distinguish different components or structures and do not indicate any order or importance. Furthermore, non-absolute terms such as "usually," "may," and "optionally" mentioned in the embodiments of this application are intended to provide preferred or exemplary guidance, and those skilled in the art can make adjustments according to the actual situation.

[0029] The following examples further illustrate the spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking as described in this application, and its preparation method. The examples are implemented based on the technical solution of this application, providing detailed implementation methods and specific operating procedures; however, the scope of protection of this application is not limited to the following examples.

[0030] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0031] Perfluoroalkyl (meth)acrylate copolymer: Purchased from Tianjin Fankai New Materials Co., Ltd.; Polytetrafluoroethylene micro powder: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number P301928; Nano titanium dioxide: Purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number T767970; Polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer (P123): Purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Polyethylene grafted with maleic anhydride: Purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number P304899, grafting rate 8%; Ethylene / methacrylic acid ionomer, sodium ion (ionomer): purchased from Shanghai Saikerui Biotechnology Co., Ltd., product number SCPP-80288, melt index 10 g / 10min; Polypropylene (PP): Purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number P110850, melt index 12 g / 10min.

[0032] Test case Critical number of friction cycles at which "interlayer delamination" occurs: The test was conducted according to GB / T 21196.2: "Textiles - Martindale Method for Determination of Abrasion Resistance of Fabrics - Part 2: Determination of Specimen Breakage". The test trajectory was a Lissajous curve, and the abrasive was standard wool friction cloth. The number of friction cycles at which "interlayer delamination" or "obvious delamination and slippage" first occurred during the friction process was recorded. The critical number of friction cycles at which "interlayer delamination" occurs represents the bonding performance of spunbond nonwoven fabric. One-way moisture conduction index (OMMC): The OMMC is determined using a liquid water dynamic transport performance tester (MMT) in accordance with GB / T 32600 standard. The higher the value, the better the one-way moisture conduction performance. The OMMC retention rate after 10 standard water washes is also tested. Static friction coefficient: The static friction coefficient of the inner surface of the skin-contacting device is tested using a friction coefficient measuring instrument. The smaller the value, the smoother the surface.

[0033] Example 1 A spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking includes a skin-adhering inner layer, an intermediate layer, and an evaporating outer layer. The skin-adhering inner layer comprises 98.5% PP and 1.5% first masterbatch, wherein the first masterbatch is a mixture of perfluoroalkyl (meth) acrylate copolymer and polytetrafluoroethylene micropowder in a mass ratio of 3:1. Based on the total mass of the raw material components of the intermediate layer as 100%, the intermediate layer comprises 96% PP, 1% second masterbatch and 3% grafted modified resin, wherein the second masterbatch is a mixture of nano titanium dioxide and P123 in a mass ratio of 3:1, and the grafted modified resin is a mixture of polyethylene grafted with maleic anhydride and ethylene / methacrylic acid ionomer and sodium ions in a mass ratio of 1:1. Based on the total mass of the raw material components of the evaporation outer layer being 100%, the evaporation outer layer comprises 95% PP and 5% second masterbatch.

[0034] The preparation method of the spunbond nonwoven fabric described in Example 1 includes the following steps: S1. Weigh the raw material components of the skin-adhesive inner layer, the middle layer and the evaporation outer layer according to the formula, and place the raw material components of the skin-adhesive inner layer in the screw extruder of the first die head, the raw material components of the middle layer in the screw extruder of the second die head and the raw material components of the evaporation outer layer in the screw extruder of the third die head for extrusion melting and filtration. The first die has a spinneret orifice diameter of 0.5 mm, a spinneret orifice density of 4000 orifices / meter, a metering pump speed of 30 rpm, a suction pressure of 1000 Pa under the screen, and a cold air temperature of 15 ℃. The second die has a spinneret orifice diameter of 0.4 mm, a spinneret orifice density of 5000 orifices / meter, a metering pump speed of 20 rpm, a suction pressure of 1800 Pa under the screen, and a cold air temperature of 15 ℃. The third die has a spinneret orifice diameter of 0.3 mm, a spinneret orifice density of 6000 orifices / meter, a metering pump speed of 12 rpm, a suction pressure of 3000 Pa under the screen, and a cold air temperature of 8 ℃. The screw extruder temperature corresponding to the first, second, and third dies is 230 ℃, the spinning box temperature is 250 ℃, the hot rolling temperature is 165 ℃, and the linear pressure is 70 N / mm. The filtered product is fed to the spinneret corresponding to each die head for confluence spinning, and then the fibers are separated and laid into a web. From bottom to top, the web consists of a skin-adhering inner layer fiber web with an average fiber fineness of 3D, an intermediate layer fiber web with an average fiber fineness of 1.8D, and an evaporation outer layer fiber web with an average fiber fineness of 0.7D. S2. The inner skin-adhesive fiber web, the middle fiber web, and the outer evaporation fiber web are pre-consolidated, main-consolidated, cooled and shaped, and then wound up to obtain the spunbond nonwoven fabric.

[0035] Example 2 A spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking includes a skin-adhering inner layer, an intermediate layer, and an evaporating outer layer. The skin-adhering inner layer comprises 99.2% PP and 0.8% first masterbatch, wherein the first masterbatch is a mixture of perfluoroalkyl (meth)acrylate copolymer and polytetrafluoroethylene micropowder in a mass ratio of 4:1. Based on the total mass of the raw material components of the intermediate layer as 100%, the intermediate layer comprises 97.2% PP, 0.8% second masterbatch and 2% grafted modified resin, wherein the second masterbatch is a mixture of nano titanium dioxide and P123 in a mass ratio of 4.5:1, and the grafted modified resin is a mixture of polyethylene grafted with maleic anhydride and ethylene / methacrylic acid ionomer and sodium ions in a mass ratio of 1.5:1. Based on the total mass of the raw material components of the evaporation outer layer being 100%, the evaporation outer layer comprises 96.5% PP and 3.5% second masterbatch.

[0036] The preparation method of the spunbond nonwoven fabric described in Example 2 includes the following steps: S1. Weigh the raw material components of the skin-adhesive inner layer, the middle layer and the evaporation outer layer according to the formula, and place the raw material components of the skin-adhesive inner layer in the screw extruder of the first die head, the raw material components of the middle layer in the screw extruder of the second die head and the raw material components of the evaporation outer layer in the screw extruder of the third die head for extrusion melting and filtration. The first die has a spinneret orifice diameter of 0.6 mm, a spinneret orifice density of 4500 orifices / meter, a metering pump speed of 40 rpm, a suction pressure of 1500 Pa under the screen, and a cold air temperature of 20 ℃. The second die has a spinneret orifice diameter of 0.5 mm, a spinneret orifice density of 5500 orifices / meter, a metering pump speed of 28 rpm, a suction pressure of 2500 Pa under the screen, and a cold air temperature of 20 ℃. The third die has a spinneret orifice diameter of 0.4 mm, a spinneret orifice density of 7000 orifices / meter, a metering pump speed of 18 rpm, a suction pressure of 4500 Pa under the screen, and a cold air temperature of 12 ℃. The screw extruder temperature corresponding to the first, second, and third dies is 250 ℃, the spinning box temperature is 280 ℃, the hot rolling temperature is 175 ℃, and the linear pressure is 80 N / mm. The filtered product is fed to the spinneret corresponding to each die head for confluence spinning, and then the fibers are separated and laid into a web. From bottom to top, the web consists of a skin-adhering inner layer fiber web with an average fiber fineness of 3.5D, an intermediate layer fiber web with an average fiber fineness of 2.5D, and an evaporation outer layer fiber web with an average fiber fineness of 1.5D. S2. The inner skin-adhesive fiber web, the middle fiber web, and the outer evaporation fiber web are pre-consolidated, main-consolidated, cooled and shaped, and then wound up to obtain the spunbond nonwoven fabric.

[0037] Example 3 A spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking includes a skin-adhering inner layer, an intermediate layer, and an evaporating outer layer. The skin-adhering inner layer comprises 99.8% PP and 0.2% first masterbatch, wherein the first masterbatch is a mixture of perfluoroalkyl (meth) acrylate copolymer and polytetrafluoroethylene micropowder in a mass ratio of 5:1. Based on the total mass of the raw material components of the intermediate layer as 100%, the intermediate layer comprises 98.5% PP, 0.5% second masterbatch and 1% grafted modified resin, wherein the second masterbatch is a mixture of nano titanium dioxide and P123 in a mass ratio of 6:1, and the grafted modified resin is a mixture of polyethylene grafted with maleic anhydride and ethylene / methacrylic acid ionomer and sodium ions in a mass ratio of 2:1. Based on the total mass of the raw material components of the evaporation outer layer being 100%, the evaporation outer layer comprises 98% PP and 2% second masterbatch.

[0038] In preparing the spunbond nonwoven fabric, the method of Example 2 was followed, except that all the raw material components in Example 2 were replaced with the raw material components of Example 3.

[0039] Comparative Example 1 The method of Example 2 is implemented, except that the grafted modified resin in the intermediate layer is completely replaced with PP. That is, based on the total mass of the raw material components of the intermediate layer being 100%, the intermediate layer includes 99% PP and 1% second masterbatch.

[0040] Comparative Example 2 The procedure was carried out in accordance with Example 2, except that the polyethylene grafted maleic anhydride in the grafted modified resin was completely replaced with ethylene / methacrylic acid ionomer and sodium ions.

[0041] Comparative Example 3 The procedure was carried out in accordance with Example 2, except that the sodium ions in the ethylene / methacrylic acid ionomer in the grafted modified resin were completely replaced with polyethylene grafted maleic anhydride.

[0042] Comparative Example 4 The method was implemented as in Example 2, except that all the nano-titanium dioxide in the second masterbatch was replaced with P123.

[0043] Comparative Example 5 The method was implemented as in Example 2, except that all P123 in the second masterbatch was replaced with nano-titanium dioxide.

[0044] Comparative Example 6 The method described in Example 2 is different in that a spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking is provided, comprising a skin-adhering inner layer, an intermediate layer, and an evaporating outer layer. The skin-adhering inner layer comprises 98% PP and 2% first masterbatch, based on the total mass of its raw material components (100%). The intermediate layer comprises 96% PP, 2% second masterbatch, and 2% grafted modified resin, based on the total mass of its raw material components (100%). The evaporating outer layer comprises 99% matrix resin and 1% second masterbatch, based on the total mass of its raw material components (100%).

[0045] Comparative Example 7 The process was carried out in accordance with Example 2, except that in the preparation of spunbond nonwoven fabric, the diameter of the spinneret holes of the first, second and third diester heads was 0.6 mm, the spinneret hole density was 4500 holes / meter, the metering pump speed was 40 rpm, the under-web suction was 1500 Pa, the cold air temperature was 20 ℃, and the average fiber fineness of the final skin-adhering inner fiber web, middle fiber web and evaporation outer fiber web was 2.5D.

[0046] The spunbond nonwoven fabrics prepared in Examples 1-3 and Comparative Examples 1-7 were subjected to Martindale abrasion resistance, unidirectional moisture conductivity index, and static friction coefficient tests. The test results are shown in Table 1. Table 1

[0047] As can be seen from Table 1, compared with Comparative Example 1, when the intermediate layer lacks grafted modified resin, the interlayer delamination is very likely to occur due to the low surface energy effect of the perfluorinated masterbatch in the skin-adhesive inner layer. In Comparative Example 1, severe interlayer delamination occurred in the very early stages of the Martindale test (within 100-200 rubs). The inner skin layer and the outer evaporated layer were crumpled and disintegrated like two unrelated pieces of paper, resulting in wrinkling, delamination, and even tearing of the fabric. This is because pure PP is a completely nonpolar macromolecule. It is sandwiched between the extremely hydrophobic fluorinated inner skin layer and the strongly polar hydrophilic polyether evaporated outer layer. There is neither chemical bond anchoring nor dipole or ionic attraction. During hot rolling, pure PP cannot penetrate the low surface energy "weak boundary layer" of the fluoride in the inner skin layer, nor can it generate any affinity with the hydroxyl / ether bonds of the outer layer. This is a typical interfacial failure caused by thermodynamic incompatibility. Comparative Example 2 showed some improvement in adhesion performance (e.g., able to withstand 500-800 cycles), but subsequently, localized blistering and slippage appeared on the fabric surface. Close observation of the cross-section revealed that the inner skin layer adhered tightly to the middle layer, but adhesion occurred between the middle layer and the evaporated outer layer. This is because the most significant characteristic of ionomers is the presence of metal ion clusters. In the molten state, they exhibit extremely strong fluidity and "dipole-induced" adhesion to low surface energy materials (such as fluoropolymers), thus holding the inner skin layer firmly. However, ionomers lack groups capable of undergoing strong chemical reactions or high-density hydrogen bonding with the evaporated outer layer polyether / PEO. When faced with the extremely dense, highly polar groups of the evaporated outer layer, the simple ionic / dipole interaction forces eventually fatigued and fractured under repeated high-intensity mechanical rubbing, leading to interface failure of the middle layer / evaporated outer layer.

[0048] Comparative Example 3 also exhibited moderate adhesion (approximately 400-600 cycles), subsequently leading to delamination. However, in stark contrast to Comparative Example 2, the intermediate layer and the evaporated outer layer were tightly bonded, while the inner skin-adhesive layer was rubbed off, adhering like peeling skin. This is because maleic anhydride groups readily open their rings upon heating, forming an extremely strong, high-density hydrogen bond network with the polyether ester / PEO in the evaporated outer layer, making the intermediate layer / evaporated outer layer interface virtually indestructible. However, the highly nonpolar and strongly repulsive fluorinated molecular chains, coupled with the lack of the unique elastomer conformation and ion-inducing ability of ionomers, prevented the formation of an effective anchor on the inner skin-adhesive layer surface. Consequently, under frictional shear force, the inner skin-adhesive layer / intermediate layer interface collapsed first.

[0049] Comparing Example 2 with Comparative Examples 4 and 5, it can be seen that in Comparative Example 4, due to the lack of the "matrix anchoring effect" of inorganic nano-titanium dioxide, its hydrophilicity severely decreased after 10 washes, with the OMMC index dropping from 0.89 to 0.35. In Comparative Example 5, the lack of steric hindrance coating from the P123 macromolecule led to the aggregation of inorganic particles, making spinning difficult and resulting in a low initial OMMC index (only 0.65). The embodiments of this application, through organic-inorganic compounding, achieve excellent unidirectional moisture wicking ability (OMMC≥0.88) while also providing extremely excellent long-term stability against washing. In summary, the spunbond nonwoven fabric provided in this application, through a reasonable layer structure ratio and a special preparation process, effectively overcomes the industry problem of mutual repulsion between "high smoothness and low friction" and "interlayer composite adhesion" in the prior art, and achieves excellent smoothness, extremely high anti-adhesion performance and long-lasting water-resistant one-way moisture-wicking effect.

[0050] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application.

Claims

1. A spunbond nonwoven fabric with a smooth feel and long-lasting unidirectional moisture wicking, comprising a skin-friendly inner layer, a middle layer, and an evaporation outer layer, characterized in that, Based on the total mass of the raw material components of the inner skin layer as 100%, the inner skin layer comprises 98.5~99.8% matrix resin and 0.2~1.5% first masterbatch; Based on the total mass of the raw material components of the intermediate layer as 100%, the intermediate layer comprises 96-98.5% matrix resin, 0.5-1% second masterbatch and 1-3% grafted modified resin. Based on the total mass of the raw material components of the evaporation outer layer being 100%, the evaporation outer layer comprises 95-98% matrix resin and 2-5% second masterbatch; The first masterbatch is a fluorinated compound, the second masterbatch is a mixture of nano-titanium dioxide and polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and the grafted modified resin is a mixture of polyethylene grafted with maleic anhydride and ionomer.

2. The spunbond nonwoven fabric according to claim 1, characterized in that, The first masterbatch is a mixture of perfluoroalkyl (meth) acrylate copolymer and polytetrafluoroethylene micro powder in a mass ratio of 3~5:

1.

3. The spunbond nonwoven fabric according to claim 1 or 2, characterized in that, The mass ratio of nano-titanium dioxide to poly(ethylene oxide-poly(propylene oxide-poly(ethylene oxide)) triblock copolymer is 3~6:

1.

4. The spunbond nonwoven fabric according to claim 1 or 2, characterized in that, The ionic polymer is an ethylene-methacrylic acid copolymer containing sodium ions, and the mass ratio of polyethylene grafted with maleic anhydride to the ethylene-methacrylic acid copolymer containing sodium ions is 1~2:

1.

5. The spunbond nonwoven fabric according to claim 4, characterized in that, The grafting rate of the polyethylene grafted with maleic anhydride is 8-12%.

6. The spunbond nonwoven fabric according to claim 5, characterized in that, The melt index ratio of the ionomer to the matrix resin is 0.8~1.2:

1.

7. The spunbond nonwoven fabric according to claim 1 or 2, characterized in that, The matrix resin is one or more of thermoplastic polyester elastomer, polyester, polypropylene, and polylactic acid.

8. A method for preparing the spunbond nonwoven fabric according to any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: S1. Weigh the raw material components of the skin-adhering inner layer, the middle layer, and the evaporation outer layer according to the formula. Place the raw material components of the skin-adhering inner layer in the screw extruder of the first die, the raw material components of the middle layer in the screw extruder of the second die, and the raw material components of the evaporation outer layer in the screw extruder of the third die for extrusion melting and filtration. Then, transport the filtered products to the spinneret corresponding to each die for confluence spinning. Then, separate the fibers and lay them into webs. From bottom to top, the average fiber fineness of the inner layer fiber web, the middle layer fiber web, and the evaporation outer layer fiber web decreases sequentially. S2. The inner skin-adhesive fiber web, the middle fiber web, and the outer evaporation fiber web are pre-consolidated, main-consolidated, cooled and shaped, and then wound up to obtain the spunbond nonwoven fabric.

9. The method for preparing spunbond nonwoven fabric according to claim 8, characterized in that, The average fiber fineness of the inner skin-adhering fiber mesh is 3~3.5D, the average fiber fineness of the middle layer fiber mesh is 1.8~2.5D, and the average fiber fineness of the outer evaporation fiber mesh is 0.7~1.5D.

10. The method for preparing spunbond nonwoven fabric according to claim 8 or 9, characterized in that, The first die head has a spinneret orifice diameter of 0.5~0.6 mm, a spinneret orifice density of 3500~4500 orifices / meter, a metering pump speed of 30~40 rpm, a suction pressure of 1000~1500 Pa under the mesh, and a cold air temperature of 15~20 ℃; the second die head has a spinneret orifice diameter of 0.4~0.5 mm, a spinneret orifice density of 4500~5500 orifices / meter, a metering pump speed of 20~28 rpm, a suction pressure of 1800~2500 Pa under the mesh, and a cold air temperature of 15~20 ℃; the third die head has a spinneret orifice diameter of 0.3~0.4 mm, a spinneret orifice density of 5500~7000 orifices / meter, a metering pump speed of 12~18 rpm, a suction pressure of 3000~4500 Pa under the mesh, and a cold air temperature of 8~12 ℃.

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