Triple gradient structure one-way moisture conduction non-woven composite fabric and preparation method thereof

Abstract

The invention discloses a triple gradient structure one-way moisture conduction non-woven composite fabric and a preparation method thereof, and belongs to the technical field of garment materials. The non-woven composite fabric comprises a hydrophobic fiber web layer, a fine fiber web diffusion layer and a hydrophilic fiber web layer which are compounded in a needling or spunlace mode, the water contact angles of the hydrophobic fiber web layer, the fine fiber web diffusion layer and the hydrophilic fiber web layer are sequentially decreased, and the fiber fineness is sequentially decreased; the fiber fineness in the hydrophobic fiber net layer is greater than or equal to 2D; the porosity of the hydrophobic fiber web layer, the porosity of the fine fiber web diffusion layer and the porosity of the hydrophilic fiber web layer are sequentially reduced; fibers in the hydrophobic fiber web layer and the hydrophilic fiber web layer are mainly arranged in the output direction of the non-woven machine, and the fine fiber web diffusion layer comprises fibers which are arranged parallel to and inclined to the output direction of the non-woven machine. The non-woven fabric disclosed by the invention can realize rapid one-way moisture conduction, and has the characteristics of good uniformity and soft garment fabric.

Description

Technical Field

[0001] The invention belongs to the technical field of clothing fabrics, and in particular relates to a triple gradient structure unidirectional moisture-conducting nonwoven composite fabric and a preparation method thereof. Background Art

[0002] The global fashion industry has an annual output value of about $3 trillion, but it also produces 20% of the world's wastewater (the world's second largest water-consuming industry) and 10% of the world's carbon emissions (more than the total emissions of all international flights and shipping). The production process of traditional clothing fabrics is not conducive to environmental protection. Under the background of "double carbon", the industry needs to adjust and improve the environmental protection of production and transform towards a healthier working environment. Among them, the production of non-woven products often replaces the complicated spinning, weaving, cutting, sewing and other production processes in the past with needle punching and spunlace processes, and directly lays the fibers into non-woven fabrics, which simplifies the process of converting raw materials into clothing fabrics; and there is no need to use the traditional high-energy consumption process of the industry to make yarns, but to use needle punching and spunlace methods to connect the fibers, reducing energy consumption. It can be seen that non-woven materials have the characteristics of a wide range of raw materials, short process flow, flexible and diverse processes, high production efficiency, a wide variety of products and a wide range of applications. Therefore, these characteristics of non-wovens can be used to apply non-woven fabrics in the field of clothing fabrics, making the preparation of clothing more energy-saving, low-pollution and sustainable.

[0003] At present, in the field of non-woven clothing fabrics, there are few applications in the market at home and abroad, and there is a big gap. The only products on the market have great limitations, such as stuffiness, airtightness, easy pilling and other problems when wearing, or the fabric is stiff to the touch, similar to film and paper materials, resulting in the garment not having good comfort. Ordinary clothing fabrics are difficult to meet the current higher daily needs of people, so more and more functional fabrics are now pouring into the market. For example, a one-way moisture-conducting functional fabric product usually refers to a product in which moisture and heat are quickly transferred from the inner layer of the fabric (skin contact layer) to the outer layer of the fabric (air contact layer) for evaporation and drying, and moisture and heat do not stay in the inner layer. This type of fabric does not stick to the skin, is very comfortable to wear, and is the preferred material for sportswear fabrics. However, most of the common moisture-conducting textile fabrics are functionally finished on the front and back of the fabric with hydrophilic and hydrophobic chemical finishing agents, which is easy to cause pollution to the environment.

[0004] Some water-conducting nonwoven materials usually also use a double-layer hydrophilic and hydrophobic fiber web structure to form a wetting gradient effect, thereby achieving unidirectional moisture conduction. These existing technologies mainly reinforce the composite fiber web through multiple spunlace or needle-punched nonwoven processes, and the fiber web before composite is only obtained by parallel laying. However, the above nonwoven processing method is only suitable for the preparation of nonwoven composite materials for specific industries. The nonwoven materials prepared in this way are prone to pilling, have a stiff hand feel, and have certain defects in mechanical properties. Due to the lack of mechanical properties, wearing properties and other properties, they cannot be used in unidirectional moisture-conducting functional clothing fabrics. Summary of the invention

[0005] In view of this, the present invention provides a triple gradient structure unidirectional moisture-conducting non-woven composite fabric and a preparation method thereof. The non-woven composite fabric can not only achieve rapid unidirectional moisture-conducting but also has the characteristics of good uniformity and soft clothing fabric.

[0006] The present invention provides a triple gradient structure unidirectional moisture-conducting nonwoven composite fabric, comprising a needle-punched or spunlace composite hydrophobic fiber mesh layer, a fine fiber mesh diffusion layer and a hydrophilic fiber mesh layer, wherein the water contact angles of the hydrophobic fiber mesh layer, the fine fiber mesh diffusion layer and the hydrophilic fiber mesh layer decrease in sequence;

[0007] The fiber fineness in the hydrophobic fiber mesh layer, the fine fiber mesh diffusion layer and the hydrophilic fiber mesh layer decreases in sequence; the fiber fineness in the hydrophobic fiber mesh layer is above 2D;

[0008] The porosity of the hydrophobic fiber mesh layer, the fine fiber mesh diffusion layer and the hydrophilic fiber mesh layer decreases in sequence; the fibers in the hydrophobic fiber mesh layer and the hydrophilic fiber mesh layer are mainly arranged along the output direction of the nonwoven machine, the fine fiber mesh diffusion layer includes fibers arranged parallel to and oblique to the output direction of the nonwoven machine, and the surface density of the fine fiber mesh diffusion layer is less than 60g / m 2 .

[0009] The main working principle of unidirectional moisture conduction is that the capillary pressure of the fiber assembly on the front and back sides of the material is different, that is, the front and back layers have different capillary water absorption capacities, and thus the capillary wetting effects are different. The contact angle θ1 of the hydrophilic layer generally ranges from 0° to 90°, and the contact angle θ2 of the hydrophobic layer ranges from 90° to 180°. The capillary pressure difference formula is as follows:

[0010]

[0011] Among them, △P is the capillary pressure difference, P1 is the capillary pressure of the hydrophilic layer fiber assembly, P2 is the capillary pressure of the hydrophobic layer fiber assembly, and γ is the surface tension (the two capillaries are in the same liquid, and the surface tension is the same, that is, γ1=γ2=γ). is the equivalent radius of the capillary of the hydrophilic layer fiber assembly, is the equivalent capillary radius of the hydrophobic layer fiber assembly.

[0012] It can be seen that the size of △P is not only controlled by the contact angle, but the fiber diameter is also a major influencing factor. Through the differential capillary effect model, it is concluded that the pore size of the fiber mesh is also an important factor affecting the unidirectional moisture conduction transmission. In addition, when the contact angle difference is too large, even if a layer of hydrophilic fiber and a layer of hydrophobic fiber are satisfied, the unidirectional moisture conduction effect will still disappear. Therefore, the realization of unidirectional moisture conduction is too limited to only use the wetting gradient (difference between hydrophilic and hydrophobic fiber materials). Therefore, when one side is hydrophilic and the other side is hydrophobic, the fiber assembly with a hydrophilic and hydrophobic composite structure will produce a wetting gradient, that is, a capillary pressure difference, forming a unidirectional moisture conduction effect. In addition, the finer the diameter of the hydrophilic layer fiber, the smaller the equivalent radius of the hydrophilic layer fiber mesh capillary, the thicker the diameter of the hydrophobic layer fiber, the larger the equivalent radius of the hydrophobic layer fiber mesh capillary, and then the greater the capillary pressure difference generated, that is, due to the changes in the fiber diameter gradient and the fiber mesh pore gradient, the unidirectional moisture conduction effect will also appear.

[0013] In order to overcome the shortcomings of the prior art, the present invention mainly selects fiber diameter and wettability, and adjusts the overall structure and fiber mesh pore size to prepare a non-woven composite fabric with a three-layer structure of wettability gradient, pore size gradient, and fiber diameter gradient. The non-woven composite fabric has a fast unidirectional moisture conduction function, and its mechanical properties fully meet the standards for wearing, and can be used as a clothing fabric.

[0014] See Figure 1 , wherein 1 is a hydrophobic fiber mesh layer, 2 is a fine fiber diffusion layer, 3 is a hydrophilic fiber mesh layer, 4 is a hydrophobic single fiber, 5 is a single fine fiber, and 6 is a hydrophilic single fiber. The embodiment of the present invention provides a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure, which is composed of a three-layer design structure of a hydrophobic fiber mesh layer 1 (referred to as a hydrophobic layer or water-repellent layer), a fine fiber diffusion layer 2, and a hydrophilic fiber mesh layer 3 (referred to as a hydrophilic layer). Among them, the hydrophobic fiber mesh layer 1 is composed of a plurality of hydrophobic single fibers 4 with relatively the thickest diameters, the fine fiber diffusion layer 2 is composed of a plurality of single fine fibers 5 with relatively thinner diameters, and the hydrophilic fiber mesh layer 3 is composed of a plurality of hydrophilic single fibers 6 with relatively the thinnest diameters; the water contact angles of the three layers decrease successively, Figure 1 The fiber fineness gradient difference and pore size gradient difference are shown in the figure.

[0015] Moreover, the fibers in the hydrophobic fiber web layer 1 and the fibers in the hydrophilic fiber web layer 3 are oriented and arranged along the output direction of the nonwoven machine; while the fibers in the fine fiber diffusion layer 2 are arranged parallel and oblique to the output direction of the nonwoven machine, which can be formed by cross-laying and multi-stage drafting, and the fibers in each layer of thin fiber web inside are arranged randomly. Furthermore, due to the transfer between fiber layers caused by the nonwoven reinforcement process, only the hydrophobic fibers are transferred, while the hydrophilic fibers are not transferred and no new hydrophilic channels are added. In addition, the nonwoven fabric is mainly chemical fibers and / or semi-chemical fibers, that is, synthetic fibers and / or semi-synthetic fibers.

[0016] The fiber fineness in the hydrophobic fiber mesh layer is above 2D; preferably, the fiber material in the hydrophobic fiber mesh layer is polyolefin and / or polyester, such as polypropylene fiber (PP fiber), polyethylene terephthalate fiber (PET fiber), hydrophobic ES fiber and other hydrophobic fibers with a contact angle greater than 105°.

[0017] Preferably, the fiber fineness of the hydrophilic fiber web layer is 0.4-0.6D, further 0.4D; and / or, the hydrophilic fiber web layer is a hot air bonded hydrophilic ES fiber web layer. In a preferred embodiment of the present invention, the fibers in the hydrophilic fiber web layer are all hydrophilic ES fibers with a fineness of 0.4D, and the contact angle is 65-75°.

[0018] In an embodiment of the present invention, the fiber fineness in the fine fiber web diffusion layer may be between 0.4D and 2D. Preferably, the fine fiber web diffusion layer is composed of sea-island fibers after washing and fiber opening (which may be called a super fiber diffusion layer); more preferably, it is formed by WSPET / PA sea-island fibers with a contact angle of 85 to 95° after washing and fiber opening.

[0019] Among them, denier D is a way to express fiber fineness and belongs to the unit of linear density.

[0020] ES fiber is a chemical fiber with a skin-core composite structure, with the skin layer being PE (polyethylene) and the core layer being PET (polyester). Both hydrophilic and hydrophobic ES fibers are skin-core structures. The hydrophobic ES fiber mentioned above is 3D / 36mm with a contact angle of 125-130°, and the hydrophilic ES fiber is 0.4D / 36mm with a contact angle of 70-75° (the difference between the hydrophilic and hydrophobic properties of ES fiber is due to the hydrophilic or hydrophobic masterbatch added by upstream manufacturers when preparing chemical fiber masterbatch, which modifies the chemical fiber to make it have a difference in hydrophilicity and hydrophobicity).

[0021] Sea-island fiber is a composite fiber spun from a fiber-forming polymer dispersed in another fiber-forming polymer; in the fiber cross section, the dispersed phase is in an "island" state, while the matrix is ​​equivalent to the "sea". From the cross section of the fiber, one macromolecular component is surrounded by another macromolecular component in a fine and dispersed state, as if there are many islands in the sea. The matrix component of WSPET / PA sea-island fiber (WSPET-PA sea-island fiber) is WSPET (water-soluble polyethylene terephthalate), and the dispersed phase component is PA (polyamide, nylon). After washing and fiber opening, part of the matrix is ​​dissolved to form more entanglements of ultrafine fibers.

[0022] In the embodiment of the present invention, the hydrophobic fiber web layer 1, the fine fiber web diffusion layer 2 and the hydrophilic fiber web layer 3 are compounded by hydroentanglement to form a nonwoven fabric as a whole.

[0023] The unidirectional moisture conduction in the prior art only works along the machine output (MD) direction in the horizontal plane, resulting in the water droplets only diffusing and wetting in one direction after breaking through the water-repellent layer and reaching the intermediate mixed layer, and the transfer rate is not fast enough. In addition, the prior art does not emphasize the effect of the puncture / water needle insertion direction of the needle-punch / hydroentanglement process on the unidirectional moisture conduction. The fine fiber diffusion layer in the embodiment of the present application can accelerate the directional moisture conduction transmission rate, and the optimal process in hydroentanglement is to penetrate from the water-repellent layer to the hydrophilic layer, which has the fastest unidirectional moisture conduction effect.

[0024] Preferably, the surface density of the triple gradient structure unidirectional moisture-conducting nonwoven composite fabric is 80 to 150 g / m 2 In some specific embodiments, due to the loss of the sea component of the sea island fibers after washing and fiber opening, and the fact that a small amount of fibers are washed away by high-speed water jets during the hydroentanglement process, the final surface density of the overall fabric is less than the sum of the surface densities of the three layers after combing.

[0025] The nonwoven composite fabric with triple gradient structure provided by the embodiment of the present invention has a unidirectional moisture conduction function such as Figure 2 As shown in the figure, water droplets are quickly transferred from the inner layer of the fabric (skin contact layer) to the outer layer of the fabric (air contact layer) through the fine fiber diffusion layer.

[0026] The technical solution of the embodiment of the present application combines the two effects of wetting gradient and differential capillary action. On the one hand, it is the pressure difference caused by the difference in water adsorption capacity, and on the other hand, it is the wicking pressure difference caused by adjusting the difference in fiber mesh pore size. The two work together to achieve a better unidirectional moisture conduction effect; the application performance is: the close-fitting water-repellent layer (hydrophobic fiber mesh layer) is drier and more comfortable, the middle microfiber diffusion layer (fine fiber mesh diffusion layer) has a shorter liquid penetration time and a faster moisture diffusion rate, and the entire fabric has a larger unidirectional transfer index.

[0027] Furthermore, in the preferred embodiment of the present invention, the mechanical properties of the sea island microfiber after washing and fiber opening are greatly improved without destroying the original fabric style of the microfiber, and the microfiber is suitable for application in the field of clothing fabrics.

[0028] In the preferred embodiment of the present invention, the sea-island microfiber layer after water-soluble fiber opening has good mechanical properties and moisture absorption characteristics compared with ordinary non-woven materials, which is manifested as better breaking strength and higher wicking height of the sea-island microfiber non-woven material prepared by the same process. In addition, the outer layer of the fabric of some embodiments is an ultra-fine ES fiber mesh, which becomes softer and more comfortable after hot air reinforcement, and the inner layer of coarser ordinary water-repellent fiber plays a supporting role, making the skin contact more dry and comfortable, meeting the wearing requirements.

[0029] After being subjected to nonwoven reinforcement methods such as high needling frequency, high needle density needling, high water needle pressure, low water puncture distance, high hot air temperature, and long-term hot air bonding, the mechanical properties of nonwoven webs are usually improved, but there is also the possibility that the material itself (such as the fibers in the web) may be damaged, causing the overall mechanical properties of the web to decrease. Moreover, the entanglement between fibers generated by these nonwoven reinforcement methods generally cannot meet the mechanical requirements of clothing fabrics. However, the fiber web of the embodiment of the present invention has more entanglements of ultrafine fibers after being washed and opened, and the overall mechanical properties of the fabric can be greatly improved.

[0030] The present invention provides a method for preparing the triple gradient structure unidirectional moisture-conducting nonwoven composite fabric as described above, comprising the following steps:

[0031] A hydrophobic fiber web material, a fine fiber web material, and a hydrophilic fiber web material are provided respectively, and the water contact angle, porosity, and fiber fineness of the three materials are successively reduced; the fiber fineness in the hydrophobic fiber web material is above 2D; the fibers in the hydrophobic fiber web material and the hydrophilic fiber web material are mainly arranged along the output direction of the nonwoven machine, the fine fiber web material includes fibers arranged parallel to and oblique to the output direction of the nonwoven machine, and the surface density of the fine fiber web material is less than 60g / m 2

[0032] Laying the hydrophobic fiber web material, the fine fiber web material, and the hydrophilic fiber web material in sequence to obtain a fiber web with a three-layer structure;

[0033] The fiber web of the three-layer structure is subjected to hydroentanglement or needle punching to achieve reinforcement and compounding, so as to obtain a triple gradient structure unidirectional moisture-conducting nonwoven composite fabric.

[0034] See also Figure 3 , Figure 3The process flow diagram of the preferred embodiment of the present invention is as follows. The above-mentioned unidirectional moisture-conducting sea-island microfiber nonwoven fabric with triple gradient structure is prepared by the following method steps, that is, the preparation method steps are as follows:

[0035] Step 1: Select hydrophilic ES fiber, hydrophobic fiber and water-soluble sea-island fiber, and open and mix them respectively. Preferably, hydrophilic ES fiber with a fiber fineness of 0.4D and water-soluble sea-island fiber with a fiber fineness of 0.8D are selected, and hydrophobic fiber with a fineness ≥ 2D (can be 2D, 3D, 4D) is selected for the corresponding hydrophobic fiber web layer, such as PP fiber, PET fiber, hydrophobic ES fiber, etc.

[0036] More preferably, on the basis of the three fibers of the above-mentioned selected diameters, ES fibers with a contact angle of about 70°, WSPET / PA sea island fibers with a contact angle of about 90°, and hydrophobic fibers with a contact angle greater than 105° are selected. In a specific embodiment, hydrophobic PET fibers (3D), water-soluble sea island fibers (0.8D, PA as the island component), and hydrophilic sheath-core ES fibers (0.4D) are used; hydrophobic PET fibers are ordinary PET fibers, and their official moisture regain is generally 0.4%, and the PA component can be PA6. The hydrophilic layer can also be composed of other fibers with a fiber fineness of less than 0.6D and a contact angle of less than 75°. The cross-sections of each fiber are conventional, and commercially available products can be used.

[0037] Preferably, the preparation of the hydrophobic fiber web material comprises: combing the hydrophobic fibers by direct laying method, so that the main fibers are laid parallel to the output direction of the nonwoven machine to form a web with a surface density of 30-60 g / m 2 Hydrophobic fiber mesh material.

[0038] Preferably, the preparation of the hydrophilic fiber web material includes: combing the hydrophilic ES fibers by direct laying so that the main fibers are laid parallel to the output direction of the nonwoven machine, and then hot air thermal bonding reinforcement is performed to obtain a hydrophilic fiber web material (which may be a hot air hydrophilic ES nonwoven fabric).

[0039] Preferably, the preparation of the fine fiber web material comprises:

[0040] The WSPET-PA sea-island fiber is combed by vertical cross-lapping method and stretched to form a surface density of 30-60g / m 2 The island fiber web;

[0041] The sea-island fiber web is subjected to water-soluble weight-reduction fiber-opening to obtain a PA island fine fiber web material (which may be a PA conductive ultrafine fiber web).

[0042] Correspondingly, the second to fifth steps of the preparation method of the specific embodiment of the present invention are as follows:

[0043] Step 2: Feed the ES fibers and hydrophobic fibers selected in the first step into the carding machine respectively, and use the direct laying method to card. After the carding is completed, the ES fibers and hydrophobic fibers are laid parallel to the output direction of the machine. The amount of feeding fiber can be adjusted. The surface density of the hydrophilic ES fiber web material formed is 30-60g / m 2 , specifically 30g / m 2 , 40g / m 2 , 50g / m 2 , 60g / m 2 The surface density of the hydrophobic fiber web (hereinafter referred to as the hydrophobic fiber web) is 30-60 g / m 2 .

[0044] Step 3: Feed the WSPET-PA sea-island fiber selected in the first step into a roller-type carding machine, and use vertical cross-laying. The clamping curtain is clamped by a pulley and swings back and forth, so that the thin carded fiber web moves horizontally on the web curtain and is laid into a fiber web with a certain number of layers and a certain thickness. The surface density of the fiber web can be adjusted by adjusting the amplitude and speed of the clamping curtain. After drafting, the surface density of the formed sea-island fiber web is 30-60g / m 2 .

[0045] In some embodiments of the present invention, the weight difference between the raw material feeding and output caused by factors such as edge suction and short fiber flying during the combing process causes fiber mass loss. Therefore, a coefficient suitable for a laboratory combing machine obtained through repeated experiments is selected and included in the calculation of the mass of the fed fiber. In some embodiments, if the ES fiber or ordinary PET fiber mentioned in the text is to be combed, it is necessary to multiply it by the laboratory combing machine coefficient 1.2 mentioned herein. For example, to prepare ES fibers with a surface density of 30-60 square meters per gram, it is necessary to feed 36-72g of ES fiber mass. If sea island fibers are to be combed, since water washing and fiber dissolution must also be considered, they must be multiplied by 1.6-1.7. Similarly, if sea island fibers with a surface density of 30 square meters per gram are to be prepared and the weight loss rate is to be above 26%, 48-51g of sea island fibers need to be fed. In addition, the order of the second and third steps can be interchanged.

[0046] Step 4: Feed the hydrophilic ES fiber web formed by parallel laying in the second step into a double-web clamped hot air penetration oven for hot air thermal bonding and reinforcement to obtain a hydrophilic ES hot air cloth. By adjusting the thermal bonding temperature in the oven, the ES hot air cloth out of the oven has the characteristics of soft and comfortable hand feel.

[0047] Preferably, in the fourth step, the double webs are fed into a hot air penetration oven under a clamping pressure of 10 N. More preferably, the hot air thermal bonding reinforcement time in the fourth step is selected to be 2 to 5 minutes.

[0048] And / or, the hydrophobic PET fiber mesh can be hydroentangled, the pre-hydroentanglement water needle pressure is adjusted to 25 bar, the main hydroentanglement water needle pressure is adjusted to 35 bar, 45 bar, 55 bar, and a hydrophobic PET spunlace fabric is obtained through continuous spraying and reinforcement with high-speed water jets.

[0049] Step 5: Feed the sea island fiber web formed by the cross-laying in the third step into the water washing and fiber opening device for water-soluble reduction and fiber opening; the water temperature can be adjusted in a gradient manner, and by controlling the step temperature of the water and the residence time of the fiber web, PA island ultrafine fiber webs with different degrees of fiber opening can be obtained, thereby obtaining PA island fiber webs with different pore sizes.

[0050] Preferably, the temperature range of the water-soluble weight-reduced fiber opening of the island fiber in the fifth step is selected to be 60-100°C (about 25°C has no effect on the fiber opening, and basically no fiber opening); more preferably, the fiber web residence time of the island fiber in the fifth step is 15-180s when opening the fiber in different temperature ranges. Further, the weight loss rate of the PA island fine fiber web material is less than 30%, such as 0-26%. In some embodiments, the water washing and fiber opening can be carried out in multiple stages, for example, the fabric / island fiber web enters the first constant temperature water bath device (set the water temperature to 60°C, the residence time is 15-30s), the second constant temperature water bath device (set the water temperature to 80°C, the residence time is 15-30s), and the third constant temperature water bath pot (set the water temperature to 100°C, the residence time is 1-2min). In addition, the order of the fourth and fifth steps can be interchanged.

[0051] In the embodiment of the present invention, the hydrophobic fiber web material, fine fiber web material, and hydrophilic fiber web material prepared above are stacked in order (arranged in CD direction) to form a fiber web with a three-layer structure; then, water spunlace or needle punching is performed to achieve reinforcement and compounding, and after drying, the triple gradient structure unidirectional moisture-conducting nonwoven composite fabric is obtained. The preferred specific steps correspond to the following:

[0052] Step 6: stack the three materials in the order of hydrophobic fiber web / PA island ultrafine fiber web / hydrophilic ES hot air cloth to obtain a "sandwich" structure fiber web.

[0053] Preferably, the hydrophilic ES hot air cloth and the hydrophobic web in the sixth step are laid straight into a web after combing, and the fibers in the web are oriented in the direction of machine output. The fibers in each thin web layer in the sixth step PA island web are highly oriented, but the web is randomly arranged after cross-laying and drafting.

[0054] Step 7: The obtained "sandwich" structure fiber web is subjected to multiple spunlaces to achieve reinforcement and compounding. By adjusting the spunlace pressure, spunlace nonwoven composite materials with different compactness can be obtained, and then conventional low-temperature drying (low-temperature drying, about 30-40°C) is performed to obtain a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure (which can be referred to as three types of gradient unidirectional moisture-conducting fabrics);

[0055] Alternatively, the obtained "sandwich" structure fiber web is needle-punched for reinforcement. Specifically, the "sandwich" structure fiber web can be placed on the mesh curtain of the needle punching machine, and the hydrophobic fiber web material is oriented toward the needle to ensure that the needle is vertically shot from the hydrophobic layer into the hydrophilic layer. Preferably, the fiber web is subjected to one pre-needle punch and two main needle punches, so as to obtain a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure.

[0056] In some embodiments, the multi-pass water-jet reinforcement includes pre-water-jet and main water-jet; for example, the pre-water-jet water pressure can be adjusted to 25 bar, and the main water-jet water pressure can be adjusted to 45-65 bar, 65-85 bar, and 85-105 bar. Place the "sandwich structure fiber net" on the needle loom screen, with the hydrophobic layer facing the water needle, to ensure that the water jet is vertically injected from the hydrophobic layer into the hydrophilic layer. Relying on high-pressure water, through the water spray plate in the water-jet head, fine high-pressure water jets are formed to continuously spray the fiber net on the drag net screen. Under the dual effects of the direct impact force of the water needle and the reflected water flow force, the fibers in the fiber net are displaced, interlaced, entangled and embraced with each other, forming countless mechanical bonds, thereby reinforcing the fiber net.

[0057] In some other specific embodiments, the pre-needling process parameters include: a needling frequency of 100 punctures / min, a needling stroke of 60 mm, and a single needle plate downward needling method; the main needling process parameters include: a needling frequency of 300 punctures / min for the first pass, a needling frequency of 500 punctures / min for the second pass, a needling stroke of 60 mm, and a single needle plate downward needling method. As the needle passes through the fiber web layer, the fibers are entangled with each other during the movement. At the same time, due to the friction and the up and down displacement of the fibers, the fiber web is squeezed to a certain extent, so that the fiber web is compressed, thereby reinforcing the fiber web.

[0058] Compared with the prior art, the nonwoven composite fabric provided by the embodiment of the present invention has a triple gradient of diameter gradient, fiber mesh pore size gradient, and wetting gradient, and can achieve an excellent unidirectional moisture conduction effect. In addition, the microfiber diffusion layer adopts cross-laying, and after the water droplets are transferred from the hydrophobic layer to the microfiber diffusion layer, they diffuse simultaneously in two dimensions in the horizontal plane of the diffusion layer, uniformly reducing the water drop content and uniformly diffusing to the hydrophilic layer, and its moisture conduction rate is faster and the moisture conduction effect is better. The present invention adopts a nonwoven process to prepare clothing fabrics, which has the advantages of short process, high production capacity, low cost, and no chemical additives. The obtained fabric can quickly conduct moisture in a unidirectional manner, and also has the characteristics of good uniformity, breathability, softness, and flexibility of clothing fabrics.

[0059] Furthermore, the embodiment of the present invention is reinforced and compounded based on three raw materials: sea island fiber, ES fiber and hydrophobic fiber; the water-soluble sea island fiber used in the microfiber diffusion layer is more environmentally friendly in processing than the previous alkali-soluble sea island fiber, and can achieve stable and controllable fiber opening. The island component fiber after fiber opening has better mechanical properties and moisture absorption characteristics. At the same time, after being reinforced by hot air, the ES fiber feels more delicate and soft, and can provide a certain elasticity to the fabric; and the hydrophobic fiber mesh layer with a coarse fiber diameter is used as the supporting layer of the fabric, which is conducive to a drier and more comfortable skin contact when worn, and also improves the overall tensile strength of the fabric. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 Schematic diagram of the cross-sectional structure of a unidirectional moisture-conducting nonwoven composite fabric in an embodiment of the present invention;

[0061] Figure 2 This is a schematic diagram of the one-way moisture conduction function effect of the non-woven composite fabric according to an embodiment of the present invention;

[0062] Figure 3 A schematic diagram of a process flow of a preferred embodiment of the present invention;

[0063] Figure 4 This is a graph showing the test results of the unidirectional moisture conduction performance of Example 1 of the present invention;

[0064] Figure 5 This is the national standard dynamic moisture transfer test index classification chart. DETAILED DESCRIPTION

[0065] The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application. The raw materials, methods and equipment used in the present invention are conventional raw materials, methods and equipment in the art. Unless otherwise specified, the raw materials and equipment used in the present embodiment are conventional commercially available raw materials and equipment in the art.

[0066] Among them, the sample testing methods include:

[0067] ① Mechanical properties test: YG026MB electronic fabric strength tester

[0068] The instrument is placed under standard atmospheric conditions of 20℃±2℃ and 65%±4% relative humidity. Turn on the power of the instrument and check the electronic part of the instrument. Preheat the instrument, and the general preheating time is 10-15 minutes. Prepare five groups of samples with a width of 50mm (±0.5mm) and a length of 200mm (±0.5mm), and put one end of the fabric sample into the upper clamp to ensure that the fabric is completely clamped by the clamp. Adjust the position of the sample so that the sample is in a vertical state, and then put the other end of the sample into the lower clamp, and also ensure that it is clamped. Set the stretching speed of 100mm / min on the instrument operation panel, stretch until the sample breaks, and repeat the stretching test of five groups of samples. When the test is completed, record the breaking strength and elongation of the sample, and analyze the test data.

[0069] ② Moisture conductivity test:

[0070] M290 Liquid Moisture Tester (MMT)

[0071] Turn on the power of the M290 liquid moisture tester and preheat the instrument. The preheating time is generally 15-30 minutes. Cut five groups of circular samples with a diameter of about 100mm, place the samples horizontally between the upper and lower concentric sensors of the instrument, ensure that the samples are in close contact with the sensors, and then use a fixture to apply fixed pressure to ensure that the samples will not move during the test. Use the syringe or other injection device equipped with the instrument to slowly and evenly inject 0.17 grams of standard test solution into the center of the side of the sample that contacts the skin to simulate the process of human sweat discharge. Set the test parameters on the instrument operation panel, such as test time, data collection frequency, etc., and then start the test program. The instrument starts to run automatically, and the computer will dynamically record the resistance changes of the upper and lower sensors, monitor and collect various data of the samples during the test in real time (including the surface / bottom layer soaking time, surface / bottom layer water absorption speed, surface / bottom layer maximum soaking radius, surface / bottom layer liquid moisture diffusion speed, cumulative unidirectional transmission capacity, overall liquid moisture management capacity), and analyze the experimental data.

[0072] YG(B)871 Capillary Effect Tester

[0073] Prepare the corresponding test solution according to the test requirements, and select five groups of representative fabric samples. The samples should be flat, wrinkle-free, and undamaged, and the size is generally 200mm×25mm. Fix one end of the prepared sample to the crossbar of the instrument with a tension clamp, so that the sample is suspended vertically above the water tank. Note that the sample should remain naturally drooping and must not be twisted or bent. Slowly pour the test solution preheated to the specified temperature into the water tank. The height of the test solution should make the lower end of the sample immersed in the test solution about 5-10mm. According to the test requirements, set the temperature and test time of the constant temperature bath through the control panel of the instrument. After confirming that the sample is installed correctly, the test solution height is appropriate, and the test parameters are set correctly, start the instrument to start the test. During the test, observe the rise of the liquid on the surface of the sample. When the height of the test solution rising on the sample reaches a stable state, record the height of the test solution rising on the sample and the corresponding test time at this time, and analyze the experimental data.

[0074] One-way moisture conduction performance test method: National standard GB / T 21655.1-2023 Part 1: Unidirectional combined test method; National standard GB / T 21655.2-2019 Evaluation of moisture absorption and quick-drying properties of textiles Part 2: Dynamic moisture transfer method

[0075] Example 1

[0076] like Figure 1 As shown, the triple gradient structure unidirectional moisture-conducting nonwoven fabric of this embodiment is composed of a hydrophobic layer, a hydrophilic layer and a microfiber diffusion layer in the middle, wherein the hydrophobic layer is entirely composed of hydrophobic fibers, the microfiber diffusion layer is entirely composed of WSPET / PA island fibers, and the hydrophilic layer is entirely composed of hydrophilic core ES fibers. The fibers of the hydrophobic layer and the hydrophilic layer are arranged along the machine output direction, and the WSPET / PA island fibers in the microfiber diffusion layer are cross-laid and multi-stage drafted, and the fibers inside the fiber web are arranged in a disordered manner.

[0077] The process flow of the above triple gradient structure unidirectional moisture-conducting nonwoven fabric is as follows: Figure 3 As shown, the preparation method operation steps are:

[0078] The first step: select hydrophobic fiber, WSPET / PA island fiber, and hydrophilic skin-core ES fiber; the hydrophobic fiber is hydrophobic PET fiber (ordinary PET fiber) with a specification of 3D / 54mm, the WSPET / PA island fiber is WSPET / PA island ultrafine fiber with a specification of 19 islands, and the ES fiber is hydrophilic ES fiber (contact angle of 70-75°) with a specification of 0.4D / 36mm, and open and mix them separately.

[0079] Step 2: Feed the hydrophilic ES fiber and ordinary PET fiber selected in the first step into the carding machine respectively, and use the direct laying method to card. After the carding is completed, they are laid parallel to the machine direction. The surface density of the hydrophilic ES fiber web formed is 30g / m 2 , contact angle is 74°; ordinary PET fiber mesh surface density is 30g / m 2 , the contact angle is 106°.

[0080] Step 3: Feed the WSPET-PA sea-island fiber selected in the first step into the roller-type carding machine, and use vertical cross-laying. The clamping curtain is clamped by the pulley and swings back and forth, so that the thin carded fiber web moves horizontally on the web curtain and is laid into a fiber web with a certain number of layers and a certain thickness. The surface density of the fiber web is adjusted by adjusting the amplitude and speed of the clamping curtain. The surface density of the sea-island fiber web formed after drafting is 30g / m 2 .

[0081] Step 4: feed the hydrophilic ES fiber web formed by the parallel laying in the second step into a double-web clamped hot air penetration oven for hot air thermal bonding reinforcement, adjust the oven temperature to 140°C, and dry for 3 minutes to obtain a hydrophilic ES hot air cloth.

[0082] Step 5: Feed the sea island fiber web formed by the cross-laying in the third step into the water washing and fiber opening device for water-soluble reduction and fiber opening. Adjust the water washing and fiber opening conditions to stay at 60℃ for 30s, 80℃ for 30s, and 100℃ for 1min to obtain a PA island ultrafine fiber web with a weight loss rate of 26%.

[0083] Step 6: Compound the three materials in the order of hydrophilic ES hot air cloth / PA island ultrafine fiber web / hydrophobic PET fiber web to obtain a sandwich structure fiber web, wherein the fibers in the hydrophilic ES hot air cloth and the hydrophobic PET fiber web are oriented along the machine output direction.

[0084] Step 7: Hydroentangle the obtained sandwich structure fiber web, adjust the pre-hydroentanglement water needle pressure to 25 bar, adjust the main hydroentanglement water needle pressure to 65 bar, 85 bar, 105 bar, turn the hydrophobic layer toward the water needle, ensure that the water jet is vertically injected from the hydrophobic layer to the hydrophilic layer, and rely on high-pressure water to pass through the water spray plate in the hydroentanglement head to form a fine high-pressure water needle jet, and continuously spray the fiber web on the trawl curtain. Under the dual effects of the direct impact force of the water needle and the reflected water flow force, the fibers in the fiber web are displaced, interlaced, entangled and embraced with each other, forming countless mechanical bonds, thereby reinforcing the fiber web; then low-temperature drying is performed to obtain a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure. The schematic diagram of its unidirectional moisture-conducting function can be found in Figure 2 .

[0085] Example 2

[0086] The unidirectional moisture-conducting nonwoven fabric with a triple gradient structure in this embodiment has a fiber web layered structure that is consistent with that in Example 1.

[0087] The preparation method of the above-mentioned unidirectional moisture-conducting nonwoven fabric with triple gradient structure is as follows:

[0088] The first step: select hydrophobic fiber, WSPET / PA island fiber, and ES fiber, wherein the hydrophobic fiber is hydrophobic PET fiber with a specification of 3D / 54mm, the WSPET / PA island fiber is WSPET / PA island ultrafine fiber with a specification of 19 islands, and the ES fiber is hydrophilic ES fiber with a specification of 0.4D / 36mm, and open and mix them separately.

[0089] Step 2: Feed the hydrophilic ES fiber and hydrophobic PET fiber selected in the first step into the carding machine respectively, and use the direct laying method to card. After the carding is completed, they are laid parallel to the machine direction. The surface density of the hydrophilic ES fiber web formed is 30g / m 2 , contact angle is 74°; ordinary PET fiber mesh surface density is 30g / m 2 , the contact angle is 106°.

[0090] Step 3: Feed the WSPET-PA sea-island fiber selected in the first step into the roller-type carding machine, and use vertical cross-laying. The clamping curtain is clamped by the pulley and swings back and forth, so that the thin carded fiber web moves horizontally on the web curtain and is laid into a fiber web with a certain number of layers and a certain thickness. The surface density of the fiber web is adjusted by adjusting the amplitude and speed of the clamping curtain. The surface density of the sea-island fiber web formed after drafting is 30g / m 2 .

[0091] Step 4: feed the hydrophilic ES fiber web formed by the parallel laying in the second step into a double-web clamped hot air penetration oven for hot air thermal bonding reinforcement, adjust the oven temperature to 140°C, and dry for 3 minutes to obtain a hydrophilic ES hot air cloth.

[0092] Step 5: The hydrophobic PET fiber web formed by the parallel laying in the second step is subjected to spunlace reinforcement, the pre-spunlace water needle pressure is adjusted to 25 bar, and the main spunlace water needle pressure is adjusted to 35 bar, 45 bar, and 55 bar. After continuous spray reinforcement by high-speed water jets, a hydrophobic PET spunlace fabric is obtained;

[0093] Step 6: Feed the sea island fiber web formed by the cross-laying in the third step into the water washing and fiber opening device for water-soluble reduction and fiber opening. Adjust the water washing and fiber opening conditions to stay at 60℃ for 30s, stay at 80℃ for 30s, and stay at 100℃ for 1min to obtain a PA island ultrafine fiber web with a weight loss rate of 26%.

[0094] Step 7: Compound the three materials in the order of hydrophilic ES hot air cloth / PA island ultrafine fiber web / hydrophobic PET spunlace cloth to obtain a sandwich structure fiber web; wherein the hydrophilic ES hot air cloth and the hydrophobic PET spunlace cloth are oriented and arranged in the machine output direction.

[0095] Step 8: Hydroentangle the obtained sandwich structure fiber web. Adjust the pre-hydroentanglement water needle pressure to 25 bar, adjust the main hydroentanglement water needle pressure to 45 bar, 65 bar, and 85 bar, and turn the hydrophobic layer toward the water needle to ensure that the water jet is vertically injected from the hydrophobic layer to the hydrophilic layer. Relying on high-pressure water, it passes through the water spray plate in the hydroentanglement head to form a fine high-pressure water needle jet, and continuously sprays the fiber web on the trawl curtain. Under the dual effects of the direct impact force of the water needle and the reflected water flow force, the fibers in the fiber web are displaced, interlaced, entangled and embraced with each other, forming countless mechanical bonds, thereby reinforcing the fiber web; then low-temperature drying is performed to obtain a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure. Its unidirectional moisture-conducting function is shown in the figure below. Figure 2 shown.

[0096] The hydrophilic layer and microfiber diffusion layer materials in Example 1, the fabric sample in Example 1, and the hydrophobic layer material in Example 2 were tested for wicking height and contact angle, respectively; the results are as follows.

[0097] Table 1 Wicking height results

[0098]

[0099] Figure 4 The figure is a test result of the unidirectional moisture conduction performance of Example 1 of the present invention, corresponding to the data in Table 1. Among them, the wicking height ≥ 110 mm indicates excellent moisture absorption effect.

[0100] Example 3

[0101] The unidirectional moisture-conducting nonwoven fabric with a triple gradient structure in this embodiment has a fiber web layered structure that is consistent with that in Example 1.

[0102] The preparation method of the above-mentioned unidirectional moisture-conducting nonwoven fabric with triple gradient structure is as follows:

[0103] The first step: select hydrophobic fiber, WSPET / PA island fiber, and ES fiber, wherein the hydrophobic fiber is hydrophobic PET fiber with a specification of 3D / 54mm, the WSPET / PA island fiber is WSPET / PA island microfiber with a specification of 19 islands, and the ES fiber is hydrophilic ES fiber with a specification of 0.4D / 36mm, and open and mix them separately.

[0104] Step 2: Feed the hydrophilic ES fiber and ordinary PET fiber selected in the first step into the carding machine respectively, and use the direct laying method to card. After the carding is completed, they are laid parallel to the machine direction. The surface density of the hydrophilic ES fiber web formed is 30g / m 2 , contact angle is 74°; ordinary PET fiber mesh surface density is 30g / m 2 , the contact angle is 106°.

[0105] Step 3: Feed the WSPET-PA sea-island fiber selected in the first step into the roller-type carding machine, and use vertical cross-laying. The clamping curtain is clamped by the pulley and swings back and forth, so that the thin carded fiber web moves horizontally on the web curtain and is laid into a fiber web with a certain number of layers and a certain thickness. The surface density of the fiber web is adjusted by adjusting the amplitude and speed of the clamping curtain. The surface density of the sea-island fiber web formed after drafting is 30g / m 2 .

[0106] Step 4: feed the hydrophilic ES fiber web formed by the parallel laying in the second step into a double-web clamped hot air penetration oven for hot air thermal bonding reinforcement, adjust the oven temperature to 140°C, and dry for 3 minutes to obtain a hydrophilic ES hot air cloth.

[0107] Step 5: Feed the sea island fiber web formed by the cross-laying in the third step into the water washing and fiber opening device but do not use hot water to open the fiber. Adjust the water washing and fiber opening conditions to 25°C for 2 minutes to obtain a PA island ultrafine fiber web (unopened) with a weight loss rate of 0%.

[0108] Step 6: Compound the three materials in the order of hydrophilic ES hot air cloth / PA island ultrafine fiber web / hydrophobic PET fiber web to obtain a sandwich structure fiber web, wherein the hydrophilic ES hot air cloth and the hydrophobic PET fiber web are oriented in the machine output direction.

[0109] Step 7: Hydroentangle the obtained sandwich structure fiber web. Adjust the pre-hydroentanglement water needle pressure to 25 bar, adjust the main hydroentanglement water needle pressure to 65 bar, 85 bar, and 105 bar, and point the hydrophobic layer toward the water needle to ensure that the water jet is vertically injected from the hydrophobic layer into the hydrophilic layer. Relying on high-pressure water, it passes through the water spray plate in the hydroentanglement head to form a fine high-pressure water needle jet, and continuously sprays the fiber web on the trawl curtain. Under the dual effects of the direct impact force of the water needle and the reflected water flow force, the fibers in the fiber web are displaced, interlaced, entangled and embraced with each other, forming countless mechanical bonds, thereby reinforcing the fiber web; then low-temperature drying is performed to obtain a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure. Its unidirectional moisture-conducting function is shown in the figure below. Figure 2 shown.

[0110] Example 4

[0111] The unidirectional moisture-conducting nonwoven fabric with a triple gradient structure in this embodiment has a fiber web layered structure that is consistent with that in Example 1.

[0112] The preparation method of the above-mentioned unidirectional moisture-conducting nonwoven fabric with triple gradient structure is as follows:

[0113] The first step: select hydrophobic fiber, WSPET / PA island fiber, and ES fiber; the hydrophobic fiber is hydrophobic PET fiber with a specification of 3D / 54mm, the WSPET / PA island fiber is WSPET / PA island microfiber with a specification of 19 islands, and the ES fiber is hydrophilic ES fiber with a specification of 0.4D / 36mm, and open and mix them separately.

[0114] Step 2: Feed the hydrophilic ES fiber and ordinary PET fiber selected in the first step into the carding machine respectively, and use the direct laying method to card. After the carding is completed, they are laid parallel to the machine direction (MD). The surface density of the hydrophilic ES fiber web formed is 30g / m 2 , contact angle is 74°; ordinary PET fiber web surface density is 60g / m 2 , the contact angle is 106°.

[0115] Step 3: Feed the WSPET-PA sea-island fiber selected in the first step into the roller-type carding machine, and use vertical cross-laying. The clamping curtain is clamped by the pulley and swings back and forth, so that the thin carded fiber web moves horizontally on the web curtain and is laid into a fiber web with a certain number of layers and a certain thickness. The surface density of the fiber web is adjusted by adjusting the amplitude and speed of the clamping curtain. The surface density of the sea-island fiber web formed after drafting is 50g / m 2 .

[0116] Step 4: feed the hydrophilic ES fiber web formed by the parallel laying in the second step into a double-web clamped hot air penetration oven for hot air thermal bonding reinforcement, adjust the oven temperature to 140°C, and dry for 3 minutes to obtain a hydrophilic ES hot air cloth.

[0117] Step 5: Feed the sea island fiber web formed by the cross-laying in the third step into the water washing and fiber opening device for water-soluble reduction and fiber opening. Adjust the water washing and fiber opening conditions to stay at 60℃ for 30s, stay at 80℃ for 30s, and stay at 100℃ for 1min30s to obtain a PA island ultrafine fiber web with a weight loss rate of 26%.

[0118] Step 6: Compound the three materials in the order of hydrophilic ES hot air cloth / PA island ultrafine fiber web / hydrophobic PET fiber web to obtain a sandwich structure fiber web, wherein the hydrophilic ES hot air cloth and the hydrophobic PET fiber web are oriented in the machine output direction.

[0119] Step 7: Needle punch reinforcement for the obtained sandwich structure fiber web. Place the sandwich structure fiber web on the needling machine mesh curtain, with the hydrophobic layer facing the needle, ensuring that the needle is vertically shot from the hydrophobic layer into the hydrophilic layer, and perform one pre-needle punch and two main needling punches on the fiber web. The pre-needle punching process parameters are: a needling frequency of 200 punctures / min, a needling stroke of 60mm, and a single needle plate downward needling method; the main needling process parameters are: the first needling frequency is 400 punctures / min, the second needling frequency is 500 punctures / min, and the needling stroke is 60mm. A single needle plate downward needling method is used. As the needle passes through the fiber web layer, the fibers are entangled with each other during movement. At the same time, due to the action of friction and the up and down displacement of the fibers, a certain amount of extrusion is generated on the fiber web, causing the fiber web to be compressed, thereby reinforcing the fiber web, and obtaining a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure. Its unidirectional moisture-conducting function is shown in the figure below. Figure 2 shown.

[0120] Example 5

[0121] The unidirectional moisture-conducting nonwoven fabric with a triple gradient structure in this embodiment has a fiber web layered structure that is consistent with that in Example 1.

[0122] The preparation method of the above-mentioned unidirectional moisture-conducting nonwoven fabric with triple gradient structure is as follows:

[0123] The first step: select hydrophobic fiber, WSPET / PA island fiber, and ES fiber; the hydrophobic fiber is hydrophobic PET fiber with a specification of 3D / 54mm, the WSPET / PA island fiber is WSPET / PA island microfiber with a specification of 19 islands, and the ES fiber is hydrophilic ES fiber with a specification of 0.4D / 36mm, and open and mix them separately.

[0124] Step 2: Feed the hydrophilic ES fiber and ordinary PET fiber selected in the first step into the carding machine respectively, and use the direct laying method to card. After the carding is completed, they are laid parallel to the machine direction (MD). The surface density of the hydrophilic ES fiber web formed is 30g / m 2 , contact angle is 74°; ordinary PET fiber mesh surface density is 30g / m 2 , the contact angle is 106°.

[0125] Step 3: Feed the WSPET-PA sea-island fiber selected in the first step into the roller-type carding machine, and use vertical cross-laying. The clamping curtain is clamped by the pulley and swings back and forth, so that the thin carded fiber web moves horizontally on the web curtain and is laid into a fiber web with a certain number of layers and a certain thickness. The surface density of the fiber web is adjusted by adjusting the amplitude and speed of the clamping curtain swing. The surface density of the sea-island fiber web formed after drafting is 90g / m 2 .

[0126] Step 4: Feed the sea island fiber web formed by the cross-laying in the third step into the water washing and fiber opening device for water-soluble reduction and fiber opening. Adjust the water washing and fiber opening conditions to stay at 60℃ for 15s, stay at 80℃ for 15s, and stay at 100℃ for 2min to obtain a PA island ultrafine fiber web with a weight loss rate of 26%.

[0127] Step 5: Compound the three materials in the order of hydrophilic ES fiber web-PA island ultrafine fiber web-hydrophobic PET fiber web to obtain a sandwich structure fiber web, wherein the hydrophilic ES fiber web and the hydrophobic PET fiber web are oriented in the machine output direction.

[0128] Step 6: Hydroentangle the obtained sandwich structure fiber web. Adjust the pre-hydroentanglement water needle pressure to 25bar, adjust the main hydroentanglement water needle pressure to 65bar, 95bar, and 115bar, and point the hydrophobic layer toward the water needle to ensure that the water jet is vertically injected from the hydrophobic layer into the hydrophilic layer. Relying on high-pressure water, through the water spray plate in the hydroentanglement head, a fine high-pressure water needle jet is formed to continuously spray the fiber web on the trawling curtain. Under the dual effects of the direct impact force of the water needle and the reflected water flow force, the fibers in the fiber web are displaced, interlaced, entangled and embraced with each other, forming countless mechanical bonds, thereby reinforcing the fiber web; then low-temperature drying is performed to obtain a unidirectional moisture-conducting nonwoven fabric with a triple gradient structure. Its unidirectional moisture-conducting function is shown in the figure below. Figure 2 shown.

[0129] The following are the results of MMT testing, air permeability and mechanical properties:

[0130] Table 2 MMT test (liquid moisture management test) of the embodiment

[0131]

[0132] In the MMT test, the surface layer is the water-repellent surface and the bottom layer is the hydrophilic surface. The data of the hydrophobic layer in the table is used to calculate the one-way moisture conduction index, and the data of the bottom layer, i.e. the hydrophilic layer, can be analyzed.

[0133] Figure 5It is the performance index classification tested by the dynamic moisture transfer method. The one-way moisture conduction index of the five embodiments is all>700%>300% (level 5), among which the moisture conduction index of embodiment 1 reaches 1073, which has an excellent one-way moisture conduction effect; the wetting time of the hydrophilic surface of embodiments 1, 2, 3, and 5 is all ≤3s (level 5), the water absorption rate of the hydrophilic surface of embodiments 1, 2, 3, 4, and 5 is all 50.1-100 (level 4), the maximum wetting radius of the hydrophilic surface of embodiments 1, 2, 4, and 5 is all 17.1-22 (level 4), and the liquid water diffusion rate of the hydrophilic surface of embodiments 1, 2, 3, 4, and 5 is all ≥4 (level 5), which all indicate that the hydrophilic surface has excellent moisture absorption capacity, can quickly guide the sweat on the skin contact surface of the fabric, and absorb it into the hydrophilic surface, ensuring that the skin is refreshed and dry. Among them, Example 4 has the highest gram weight and the thickest thickness, and has only two main needle punching paths when prepared by the needle punching process. The structure is relatively fluffy, and the wetting time of its hydrophilic surface is slightly worse, but still between 3.1-4.0 (level 4), and its hydrophilic surface also has good moisture absorption capacity.

[0134] Table 3 Air permeability test results of the examples

[0135] Serial number Test fabric <![CDATA[Air permeability / mm·s -1 > ① Example 1 756.68 ② Example 2 830.36 ③ Example 3 1288.93 ④ Example 4 563.29 ⑤ Example 5 626.33 ⑥ Hydrophobic layer 5310.34 ⑦ Microfiber diffusion layer 1249.80 ⑧ Hydrophilic layer 1476.59

[0136] At present, many clothing products do not have clear requirements. Some needle / woven fabrics require ≥300mm / s. All five embodiments meet the requirements, and the higher the air permeability, the better the air permeability, and the drier and more comfortable it is to wear. Among them, the air permeability of Examples 4-5 is slightly lower due to the larger weight and thicker fabric, but it still meets the ≥300mm / s requirement.

[0137] Table 4 Mechanical properties test results of the examples

[0138] Example 1 Example 2 Example 3 Example 4 Example 5 Breaking strength / N 134.8 106.8 50.3 148.3 161.2 Elongation at break % 61.2％ 63.9％ 69.7％ 92.4％ 70.9％

[0139] At present, the breaking strength range of nonwoven materials in mechanical tensile strength is mostly 10-300N, among which low-weight (30-80g / m 2 The breaking strength of spunlace products may be 5-20N, such as medical dressings, industrial wipes, etc. with higher gram weight (100-200g / m 2 ) The breaking strength of spunlace products is 20-100N.

[0140] The product weights in Examples 1-3 are all 90 g / m 2 Compared with nonwoven products with the same weight and the same process, its mechanical properties have been significantly improved, with a maximum breaking strength of 134.8N, which can meet some wearing requirements. Example 4-5 raises the product weight to 150g / m 2 After that, its mechanical properties are improved again, and the breaking strength can reach more than 150N, which is enough to meet the general wearing performance.

[0141] It can be seen from the above embodiments that the present invention implements a triple gradient structure unidirectional moisture-conducting water-soluble sea island microfiber non-woven composite fabric, as well as its preparation method and application. The unidirectional moisture-conducting non-woven fabric comprises a hydrophilic layer, a microfiber diffusion layer and a hydrophobic layer. The pore size of the fiber mesh is regulated by selecting the fiber diameter and wettability, and the water-soluble reduction fiber opening process, so as to obtain a non-woven fabric with a three-layer structure of wettability gradient, pore size gradient and fiber diameter gradient, and having a fast unidirectional moisture-conducting function. Furthermore, for the microfiber diffusion layer, the sea island fiber has better mechanical properties and hygroscopic properties after being washed and opened; the hydrophilic layer ultrafine ES fiber mesh has a more delicate and soft feel and a certain degree of elasticity after being reinforced by hot air thermal bonding; hydrophobic fibers with coarser fiber diameters are selected as the hydrophobic layer in contact with the skin, so that the skin remains dry and comfortable, while also providing support for the fabric as a whole. The preparation process of the embodiment of the present invention has the advantages of short process, high production capacity, low cost and no chemical additives. The obtained non-woven fabric can not only achieve rapid unidirectional moisture conduction, but also has the characteristics of good uniformity, breathability, softness and flexibility of clothing fabrics, which is conducive to its application in clothing and accessories.

[0142] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. The above is only a preferred implementation of the present invention. It should be pointed out that due to the limitations of textual expression and the objective existence of infinite specific structures, ordinary technicians in this technical field can make several improvements, modifications or changes without departing from the principles of the present invention, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the inventive concept and technical solution to other occasions without improvement, should be regarded as the protection scope of the present invention.

Claims

1. A triple gradient structure unidirectional moisture-conducting nonwoven composite fabric, characterized in that: It comprises a needle-punched or water-spunlace composite hydrophobic fiber mesh layer, a fine fiber mesh diffusion layer and a hydrophilic fiber mesh layer, wherein the water contact angles of the hydrophobic fiber mesh layer, the fine fiber mesh diffusion layer and the hydrophilic fiber mesh layer decrease in sequence; The fiber fineness in the hydrophobic fiber mesh layer, the fine fiber mesh diffusion layer and the hydrophilic fiber mesh layer decreases in sequence; the fiber fineness in the hydrophobic fiber mesh layer is above 2D; The porosity of the hydrophobic fiber mesh layer, the fine fiber mesh diffusion layer and the hydrophilic fiber mesh layer decreases in sequence; the fibers in the hydrophobic fiber mesh layer and the hydrophilic fiber mesh layer are mainly arranged along the output direction of the nonwoven machine, the fine fiber mesh diffusion layer includes fibers arranged parallel to and oblique to the output direction of the nonwoven machine, and the surface density of the fine fiber mesh diffusion layer is less than 60g / m 2 .

2. The triple gradient structure unidirectional moisture-conducting nonwoven composite fabric according to claim 1, characterized in that: The fiber material in the hydrophobic fiber mesh layer is polyolefin and / or polyester.

3. The triple gradient structure unidirectional moisture-conducting nonwoven composite fabric according to claim 1, characterized in that: The fiber diameter of the hydrophilic fiber web layer is 0.4-0.6D, and / or the hydrophilic fiber web layer is a hot air bonded hydrophilic ES fiber web layer.

4. The triple gradient structure unidirectional moisture-conducting nonwoven composite fabric according to any one of claims 1 to 3, characterized in that: The fine fiber web diffusion layer is formed by combing the sea-island fibers into a web and then washing and opening the fibers.

5. The triple gradient structure unidirectional moisture-conducting nonwoven composite fabric according to claim 4, characterized in that: The surface density of the triple gradient structure unidirectional moisture-conducting nonwoven composite fabric is 80 to 150 g / m 2 .

6. The method for preparing the triple gradient structure unidirectional moisture-conducting nonwoven composite fabric according to any one of claims 1 to 5, comprising the following steps: A hydrophobic fiber web material, a fine fiber web material, and a hydrophilic fiber web material are provided respectively, and the water contact angle, porosity, and fiber fineness of the three materials are successively reduced; the fiber fineness in the hydrophobic fiber web material is above 2D; the fibers in the hydrophobic fiber web material and the hydrophilic fiber web material are mainly arranged along the output direction of the nonwoven machine, the fine fiber web material includes fibers arranged parallel to and oblique to the output direction of the nonwoven machine, and the surface density of the fine fiber web material is less than 60g / m 2 ; Laying the hydrophobic fiber web material, the fine fiber web material, and the hydrophilic fiber web material in sequence to obtain a fiber web with a three-layer structure; The fiber web of the three-layer structure is subjected to hydroentanglement or needle punching to achieve reinforcement and compounding, so as to obtain a triple gradient structure unidirectional moisture-conducting nonwoven composite fabric.

7. The preparation method according to claim 6, characterized in that: The preparation of the hydrophobic fiber web material comprises: combing the hydrophobic fibers by a direct laying method, so that the main fibers are laid parallel to the output direction of the nonwoven machine to form a web with a surface density of 30-60 g / m 2 Hydrophobic fiber mesh material.

8. The preparation method according to claim 7, characterized in that: The preparation of the hydrophilic fiber web material includes: combing the hydrophilic ES fibers by direct laying method, making the main fibers lay in parallel along the output direction of the nonwoven machine, and then performing hot air thermal bonding reinforcement to obtain the hydrophilic fiber web material.

9. The preparation method according to any one of claims 6 to 8, characterized in that: The preparation of the fine fiber web material comprises: The WSPET-PA sea-island fiber is combed by vertical cross-lapping method and stretched to form a surface density of 30-60g / m 2 The island fiber web; The sea island fiber web is subjected to water-soluble weight-reduction fiber opening to obtain a PA island fine fiber web material.

10. The preparation method according to claim 9, characterized in that: The water-soluble weight-reducing fiber opening temperature is 60-100° C., and the time is 15-180 seconds; the weight loss rate of the PA island fine fiber mesh material is less than 30%.

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