Composite non-woven fabric processing method, processing system and composite non-woven fabric

Abstract

The invention relates to the technical field of non-woven materials, in particular to a composite non-woven fabric processing method and system and a composite non-woven fabric. Firstly, the first fiber net layer is subjected to electrostatic treatment, so that the surface of the first fiber net layer is provided with electrostatic charges, then hot melting polymer powder is sprayed on the surface of the second fiber net layer, then the two fiber nets are overlapped, the powder is evenly transferred to the first fiber net layer through the electrostatic adsorption effect to form a pre-composite green body, and then the pre-composite green body is subjected to ultrasonic needling through an ultrasonic needling device. According to the method, accurate distribution and transfer of the powder are achieved through electrostatic adsorption, efficient combination of fibers is achieved at the normal temperature through the synergistic effect of electrostatic adsorption and ultrasonic needling, the structural strength of the non-woven fabric is effectively improved, and the non-woven fabric has the advantages of being simple in preparation process, low in cost and easy to popularize and use. The composite strength of the composite non-woven fabric is improved while the fluffy structure and the inherent characteristics of the raw materials are kept.

Description

Technical Field

[0001] This application relates to the field of nonwoven materials technology, specifically to a composite nonwoven fabric processing method, processing system, and composite nonwoven fabric. Background Technology

[0002] Composite nonwoven fabric is a type of nonwoven fabric. It is generally made by forming fibers into a web through airflow or mechanical means using polymer chips, short fibers or filaments, and then reinforcing it through hydroentangling, needle punching or hot rolling. Finally, it is finished to form a nonwoven fabric. Its advantages are that it does not produce fiber dust, is strong, durable, silky soft, belongs to a type of reinforcing material, and also has a cotton-like feel.

[0003] Existing production methods for composite nonwoven fabrics mainly include thermal bonding, chemical bonding, hydroentangling, and ultrasonic bonding. However, during the production process, there is a contradiction between the bonding strength and softness of composite nonwoven fabrics. Thermal bonding has strong bonding strength but feels hard, while hydroentangling is soft but requires high fiber web structure and consumes a lot of energy. At the same time, the layers are usually bonded to surfaces or points, resulting in weak interfacial shear force, which makes it easy for delamination to occur during use. Therefore, it is difficult to achieve a composite effect with high strength and high bulk while maintaining the functionality of each layer.

[0004] Application content

[0005] The purpose of this application is to provide a method, system and composite nonwoven fabric processing method for composite nonwoven fabric, so as to improve composite strength while maintaining the loose structure and inherent properties of raw materials.

[0006] In a first aspect, this application provides a method for processing composite nonwoven fabrics, including:

[0007] S1: Electrostatic treatment, electrostatic treatment is performed on the first fiber web layer to give its surface a static charge of the first polarity;

[0008] S2: Powder spraying, spraying hot-melt polymer powder onto the surface of the second fiber mesh layer;

[0009] S3: Layering and adsorption, the second fiber web layer is stacked with the first fiber web layer, and the hot-melt polymer powder is attracted and transferred to the surface of the first fiber web layer through electrostatic adsorption to form a pre-composite preform.

[0010] S4: Ultrasonic needle punching composite, the pre-composite blank is passed through an ultrasonic needle punching device, the needle of the ultrasonic needle punching device vibrates under ultrasonic action and reciprocates to puncture the pre-composite blank following the feeding process.

[0011] S5; Cold rolling curing: The pre-composite preform after ultrasonic needle punching is cold rolled and shaped to obtain the finished composite nonwoven fabric.

[0012] In some embodiments, in step S1, the first fiber web layer is electrostatically treated using corona discharge or a contact electrostatic generator to make its surface potential reach 1-20kV.

[0013] In some embodiments, in step S2, the hot-melt polymer powder is selected from one or a mixture of several of the following: copolyamide (Co-PA), copolyester (Co-PES), thermoplastic polyurethane (TPU), polyethylene (PE), or ethylene-vinyl acetate copolymer (EVA).

[0014] In some embodiments, in step S2, the particle size range of the hot-melt polymer powder is 1-100 μm.

[0015] In some embodiments, step S2 further includes: electrostatically treating the hot-melt polymer powder to give the hot-melt polymer powder a second polarity opposite to the first polarity.

[0016] In some embodiments, step S3 further includes: introducing a functional film layer, wherein the precomposite preform is composed of the first fiber web layer, the second fiber web layer and the functional film layer, and the hot-melt polymer powder is located between any two layers or simultaneously at multiple interlayer interfaces.

[0017] In some embodiments, in step S4, the ultrasonic frequency of the ultrasonic acupuncture device is 20-100kHz, the power is 100-3000W, the puncture density of the needle is 10-200 punctures / cm², and the puncture depth is 1-20mm.

[0018] In some embodiments, in step S5, the surface temperature of the cooling roll is 5-25°C, and the rolling pressure is 10-200 N / mm.

[0019] Secondly, this application provides a composite nonwoven fabric processing apparatus for implementing the above-mentioned processing method, comprising the following components arranged sequentially along the processing direction:

[0020] An unwinding device is used to flatten and convey the fiber web layers.

[0021] An electrostatic generator is configured along the path of the first fiber web layer to electrostatically treat the first fiber web layer so that its surface carries a static charge of a first polarity, and to electrostatically treat the hot-melt polymer powder so that the hot-melt polymer powder carries a static charge of a second polarity opposite to the first polarity.

[0022] The powder spraying device is configured to spray hot-melt polymer powder onto the surface of the second fiber mesh layer.

[0023] A lamination device is used to laminate the second fiber web layer with the first fiber web layer, and through electrostatic adsorption, the hot-melt polymer powder is attracted and transferred to the surface of the first fiber web layer to form a pre-composite preform.

[0024] An ultrasonic needle-piercing device is used to vibrate the needle under ultrasonic action and pierce the pre-composite preform.

[0025] The cold rolling apparatus includes a pair of coolable rolls for cold rolling and shaping the pre-composite preform after ultrasonic needle punching to obtain the finished composite nonwoven fabric.

[0026] A winding device is used to collect the finished product.

[0027] Thirdly, this application provides a composite nonwoven fabric prepared by the above-mentioned processing method. The composite nonwoven fabric includes at least two layers of fiber webs. The adjacent two layers of fiber webs are bonded together by three-dimensionally dispersed bonding points formed by hot-melt polymer powder. The bonding points are distributed in a discontinuous point-like and / or columnar three-dimensional manner, and there are entangled fibers from adjacent fiber webs inside and around the bonding points.

[0028] The beneficial effects of this application are as follows: First, the first fiber web layer is electrostatically treated to give it a static charge. Then, hot-melt polymer powder is sprayed onto the surface of the second fiber web layer. Next, the two fiber web layers are stacked, and the powder is uniformly transferred to the first fiber web layer using electrostatic adsorption to form a pre-composite preform. Then, an ultrasonic needle-punching device is used to puncture the preform with high-frequency vibrating needles to achieve fiber entanglement and powder embedding. Finally, the finished product is obtained by cold rolling. This method achieves precise distribution and transfer of powder through electrostatic adsorption, and the binder forms countless tiny "welding points" between the layers through three-dimensional dispersion. The powder utilization rate is high and the distribution is uniform. The ultrasonic needle-punching technology replaces... High-temperature hot rolling melts the adhesive instantly, forming numerous, evenly distributed "bonding points." This achieves efficient bonding between fibers at room temperature, effectively improving the structural strength of the nonwoven fabric and avoiding the impact of heat damage on fiber properties. The fiber entanglement caused by needle punching further enhances the structural strength and improves the softness and breathability of the nonwoven fabric. Cold rolling further enhances the structural stability and surface smoothness. Through the synergistic effect of electrostatic adsorption and ultrasonic needle punching, the composite strength of the composite nonwoven fabric is improved while maintaining the fluffy structure and inherent properties of the raw materials. To a certain extent, this achieves a balance between high strength, high softness, and high breathability in the composite nonwoven fabric. Attached Figure Description

[0029] Figure 1 This is a flowchart of the composite nonwoven fabric processing method in this application;

[0030] Figure 2 This is a schematic diagram of the composite nonwoven fabric processing system in this application;

[0031] Figure 3 This is a schematic diagram of the process of the composite nonwoven fabric processing system in this application.

[0032] Reference numerals: 1. Unwinding device; 2. Electrostatic generator; 3. Powder spraying device; 4. Laminating device; 5. Ultrasonic needle punching device; 6. Cold rolling device; 7. Winding device. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0035] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0036] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0037] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0038] Composite nonwoven fabric is a type of nonwoven fabric. It is generally made by forming fibers into a web through airflow or mechanical means using polymer chips, short fibers or filaments, and then reinforcing it through hydroentangling, needle punching or hot rolling. Finally, it is finished to form a nonwoven fabric. Its advantages are that it does not produce fiber dust, is strong, durable, silky soft, belongs to a type of reinforcing material, and also has a cotton-like feel.

[0039] Existing methods for producing composite nonwoven fabrics mainly include thermal bonding, chemical bonding, hydroentangling, and ultrasonic bonding. Thermal bonding is similar to chemical bonding and is generally used in combination. It forms nonwoven fabrics by bonding between layers. The resulting nonwoven fabrics are stiff, have poor bulkiness, and the heat can easily damage their microstructure, leading to a decrease in functionality (such as filtration efficiency and barrier properties). Furthermore, the bonding between layers is usually surface or point bonding, with weak interfacial shear force, making delamination easy to occur during use. Hydroentangling uses high-pressure water flow to entangle fibers, but its effectiveness is limited for hydrophobic fibers or composite materials with special structures. Ultrasonic bonding is also inefficient and difficult to achieve large-area, uniform surface bonding.

[0040] This leads to a contradiction between the bonding strength and softness of composite nonwoven fabrics. Hot-rolled composites have strong bonding strength but feel hard, while spunlace composites are soft but require high fiber web structure and consume a lot of energy. At the same time, the layers are usually bonded to surfaces or points, and the interfacial shear force is weak, making it easy for delamination to occur during use. Therefore, it is difficult to achieve a composite effect of high strength and high bulkiness while maintaining the functionality of each layer.

[0041] In view of the above, the first aspect of this application provides a method, system and composite nonwoven fabric processing method.

[0042] Example 1

[0043] Firstly, referring to Figure 1 This application provides a method for processing composite nonwoven fabrics, including:

[0044] S1: Electrostatic treatment, electrostatic treatment is performed on the first fiber web layer to give its surface a static charge of the first polarity;

[0045] During the unwinding or feeding process of the first fiber web layer, a high-voltage electrostatic generator, preferably a corona discharge type or a contact type electrostatic generator, is used to perform unipolar electrostatic treatment on the traveling first fiber web layer, so that its surface is stably and uniformly covered with a first polarity (such as positive polarity) electrostatic charge. The fiber web layer can be a fiber web formed by various dry / wet methods such as spunbond, meltblown, hydroentangling, and needle punching.

[0046] By precisely controlling the discharge voltage, electrode spacing, and processing time, the surface electrostatic potential of the fiber web layer is brought to and maintained within the optimized range of 1 kV to 20 kV. If the voltage is too low (e.g., below 500V), the resulting electrostatic field is too weak to effectively charge the fiber web or overcome interference from gravity, leading to low and uneven powder adsorption efficiency. Conversely, if the voltage is too high, the effect on improving powder adsorption force becomes insignificant, and strong repulsive forces may even cause uneven adsorption layers. Therefore, the preferred operating voltage in this application is between 1 kV and 20 kV. The specific operating voltage is determined based on the subsequent spraying volume of the thermoplastic polymer powder and the size of the fiber web layer. To accommodate more situations, a wider voltage range can also be selected. The establishment of a high-potential electrostatic field provides a strong electrostatic foundation for the subsequent directional and efficient adsorption of the thermoplastic polymer powder.

[0047] S2: Powder spraying, spraying hot-melt polymer powder onto the surface of the second fiber mesh layer;

[0048] Polymer powder with specific hot-melting properties is uniformly sprayed onto the surface of the second fiber mesh layer at a preset rate using a powder spraying device, such as an electrostatic powder spraying system or a vibrating sieve spraying system. The second fiber mesh layer can be made of the same or different material as the first layer.

[0049] In some embodiments, the hot-melt polymer powder is selected from one or a mixture of several of copolyamide (Co-PA), copolyester (Co-PES), thermoplastic polyurethane (TPU), polyethylene (PE), or ethylene-vinyl acetate copolymer (EVA). The specific ratio of the hot-melt polymer powder material needs to be determined according to different non-woven fabric materials and applications. For example, when polyester (PET) fiber is selected as the fiber layer, copolyester (Co-PES) can be used as the main body, with copolyamide (Co-PA) added to improve the product's durability, or ethylene-vinyl acetate copolymer (EVA) can be added to improve the product's flexibility. Or, when producing stretchable products, thermoplastic polyurethane (TPU) can be used as the main body to improve the product's extremely high elasticity and flexibility.

[0050] In some embodiments, the particle size is controlled between 1 micrometer (μm) and 100 micrometers (μm). Powders with excessively small particle sizes (submicrometer level) are prone to agglomeration, forming particles that are difficult to disperse, leading to uneven powder spraying. Simultaneously, excessively fine powders have poor flowability, easily clogging powder spraying equipment, and exhibit unstable adsorption behavior. Conversely, excessively large particle sizes result in a mass exceeding the effective binding limit of electrostatic adsorption, leading to weak adsorption, detachment during transport and lamination, and poor melting effect. By controlling the particle size range between 1 micrometer (μm) and 100 micrometers (μm), excellent powder flowability, spray uniformity, and a suitable subsequent melting rate are ensured. In actual industrial production, to obtain the most uniform coating and the best feel, a particle size distribution of 20-80 μm is preferred. In other cases, to adapt to the needs of other products and materials, particle sizes outside the range provided in this application can be selected to achieve the desired effect.

[0051] In a more optimized and efficient embodiment, step S3 further includes a parallel powder pretreatment process: before or simultaneously with spraying, the thermoplastic polymer powder undergoes an opposite electrostatic treatment, such as triboelectric charging or corona charging, to stably impart a second polarity (e.g., negative polarity) electrostatic charge opposite to the first polarity in step S1. Pre-enabling the powder with opposite charges significantly enhances the Coulomb attraction between the powder and the first fiber network layer during subsequent lamination, resulting in higher powder transfer rates and a more uniform and dense distribution at the target layer, thereby significantly improving the bonding uniformity and overall quality of the final product.

[0052] S3: Layering adsorption, the second fiber network layer is stacked with the first fiber network layer, and the hot melt polymer powder is attracted and transferred to the surface of the first fiber network layer through electrostatic adsorption to form a pre-composite preform.

[0053] The second fiber web layer, which has been coated with powder of opposite charge in step S2, is precisely aligned and superimposed with the first fiber web layer, which has been treated with strong electrostatic charge in step S1, at a specific lamination device. At the moment of contact between the two, due to the strong electrostatic attraction of opposite charges, the hot-melt polymer powder on the surface of the second fiber web layer is attracted by the first fiber web layer, transferred across the interlayer interface, and attached to the surface of the first fiber web layer, thereby forming a pre-composite preform with uniform powder distribution. Due to the use of electrostatic adsorption, this process is almost dust-free, and the powder is evenly distributed in the gaps of the first fiber web layer, resulting in high material utilization.

[0054] In some embodiments, step S3 may also include the simultaneous introduction of a third or more layers of fiber mesh or other functional material layers, such as microporous breathable membranes, polymer barrier membranes, antibacterial layers containing active ingredients, fragrance-releasing layers, elastic membranes, etc., which can be specifically set according to product requirements.

[0055] At this point, the pre-composite preform consists of a first fiber mesh layer, a second fiber mesh layer, and a functional membrane layer inserted therebetween, forming a sandwich structure or a more complex structure. The hot-melt polymer powder can be located between any two layers, such as between the functional membrane and any fiber mesh layer, or simultaneously distributed at multiple interlayer interfaces, according to design requirements, thereby achieving a one-time composite of multifunctional, multi-layered structures, which effectively improves the applicability of the product in different application fields.

[0056] S4: Ultrasonic needle punching composite, the pre-composite green body is passed through the ultrasonic needle punching device, the needle of the ultrasonic needle punching device vibrates under the action of ultrasound and reciprocates to puncture the pre-composite green body following the feeding process.

[0057] The pre-composite preform formed above is smoothly passed through the ultrasonic needle-punching device. The core of the device is a number of transducers driven by ultrasonic generators, which convert electrical signals into high-frequency mechanical vibrations and transmit them to the needles through the amplitude transformer. This causes the powder to melt and bond through frictional heat generation. As the pre-composite preform is continuously fed, the needles puncture repeatedly, thereby melting and bonding the powder at various points.

[0058] In some embodiments, the needle vibrates violently in the vertical direction under the action of high-frequency ultrasound at 20 kHz to 100 kHz and with an ultrasonic power of 100-3000W. Specifically, 20-40 kHz is considered a low frequency, with a larger amplitude and stronger penetration, suitable for processing thicker and denser materials. 40-100 kHz is the preferred frequency in this application, offering a good balance between penetration and accuracy. However, in actual production, the ultrasonic frequency can be selected according to actual conditions such as powder particle size.

[0059] Similarly, the ultrasonic power is determined according to the actual situation. Among them, 100-500W is suitable for lightweight composites of thin, low-basis-weight materials (such as medical and health non-woven fabrics); 500-1500W is suitable for medium-thickness and basis-weight materials, which is the preferred power range in this application; 1500-3000W or higher is suitable for processing high-basis-weight, high-density materials or materials containing high-melting-point polymers, which require greater energy input to achieve effective melting.

[0060] The puncture density of the needles is 10-200 needles / cm². Among them, 10-50 needles / cm² is considered low-density needle punching, which is suitable for products that require maintaining softness and drape, forming only the necessary bonding points. Lower densities may not be able to form an effective continuous mesh structure. 50-150 needles / cm² is the preferred needle punching density range in this application, which can better balance strength and softness. 150-200 needles / cm² is considered high-density needle punching, which is used for products that require extremely high strength and density, such as synthetic leather base fabrics and high-performance filter materials. In other cases, different ranges of puncture density can be selected according to different materials and product requirements.

[0061] The puncture depth can be selected from 1 to 20 mm. Specifically, the puncture depth of the needle is 100% to 150% of the thickness of the composite blank. During the processing, the puncture depth usually needs to penetrate the bottom layer and expose a little bit of the needle tip to ensure the hooking. Among them, 1-5 mm is suitable for thin materials, 5-15 mm is suitable for medium thickness materials, and 15-20 mm is suitable for very fluffy thick wadding, padding materials, etc.

[0062] During processing, the mechanical action of the piercing needle causes fibers of different layers to entangle and interweave. Ultrasonic waves generate high-frequency friction and energy dissipation within the fibers and powder, instantly creating localized high temperatures around the needle tip. These temperatures exceed the powder's melting point, but the overall material remains at room temperature, causing the thermoplastic powder to rapidly melt into a viscous flow state and wet and coat the surrounding fibers. Under the influence of ultrasonic vibration, the molten polymer penetrates deeper into the gaps between the fiber network. After the ultrasonic energy is removed, the melt rapidly cools and solidifies, forming numerous "spot weld" bonding points, while the mechanically entangled structure is also fixed. The entire process is carried out at macroscopic room temperature, eliminating the need for external heating of the overall material, effectively avoiding damage to heat-sensitive fibers and maintaining the inherent fluffy structure and soft feel of the nonwoven fabric.

[0063] S5; Cold rolling curing: The pre-composite preform after ultrasonic needle punching is cold rolled and shaped to obtain the finished composite nonwoven fabric.

[0064] To further improve the dimensional stability, surface smoothness, mechanical properties, and hand feel of the composite material, a final cold rolling shaping is performed on the pre-composite preform after ultrasonic needle punching. A cold rolling device consisting of a pair of rollers is used, controlling the surface temperature within a low-temperature range of 5°C to 25°C. Simultaneously, a linear pressure of 10 N / mm to 200 N / mm is applied to the passing preform, further compacting the structure, improving the interlayer bonding tightness and strength. The rapid cooling effect also allows any trace amounts of molten polymer remaining after ultrasonic needle punching to quickly and completely crystallize and solidify, forming stronger bonding points. This process also imparts a smooth, flat surface appearance to the product, eliminates internal stress, and effectively prevents later shrinkage and deformation, ultimately resulting in a composite nonwoven fabric product with a complete structure, excellent performance, and a good appearance.

[0065] Example 2

[0066] Secondly, referring to Figure 2 and Figure 3 This application provides a composite nonwoven fabric processing device for implementing the processing method of Embodiment 2, including an unwinding device 1, an electrostatic generator 2, a powder spraying device 3, a laminating device 4, an ultrasonic needle punching device 5, a cold rolling device 6, and a winding device 7 arranged sequentially along the processing direction.

[0067] The unwinding device 1 is used to flatten and convey each layer of fiber web; multiple sets of unwinding devices 1 are provided to carry, flatten and precisely control the tension of the first fiber web roll, the second fiber web roll and the optional functional membrane roll respectively.

[0068] The electrostatic generator 2 is positioned along the path of the first fiber web layer 11. It is used to electrostatically treat the first fiber web layer, giving its surface a first polarity of static charge, and to electrostatically treat the hot-melt polymer powder, giving it a second polarity of static charge opposite to the first polarity. Specifically, the electrostatic generator 2 is positioned on the conveying path of the first fiber web layer and is used to perform high-voltage electrostatic treatment on one or both sides of the first fiber web layer. The electrostatic generator 2 of the powder spraying device is integrated or positioned adjacent to the powder before spraying to charge the powder with the opposite polarity. Optionally, the powder spraying device may be equipped with another set of electrostatic generators to charge the powder with the opposite polarity before spraying.

[0069] The powder spraying device 3 is set along the path of the second fiber mesh layer 12 and is used to spray hot-melt polymer powder onto the surface of the second fiber mesh layer. The powder spraying device 3 typically includes a powder hopper, a metering feeder, a diffusion spray head, etc., and is used to quantitatively and uniformly spray hot-melt polymer powder onto the surface of the second fiber mesh layer.

[0070] The laminating device 4 is used to stack the second fiber web layer with the first fiber web layer. Through electrostatic adsorption, the hot-melt polymer powder is attracted and transferred to the surface of the first fiber web layer to form a pre-composite preform. The laminating device 4 is usually composed of one or more pairs of guide rollers and pressure rollers. It is used to precisely align, stack and press the second fiber web layer with sprayed powder, the first fiber web layer with static electricity and the optional functional film layer. In this process, the electrostatic field force is used to complete the cross-layer transfer of powder to form a pre-composite preform.

[0071] The ultrasonic acupuncture device 5 is used to make the needle vibrate and puncture the pre-composite blank under ultrasonic action; the ultrasonic acupuncture device 5 is the core processing unit, including a frame, an ultrasonic power supply system, multiple ultrasonic vibration units (transducer + amplitude rod + needle), a needle plate and a drive mechanism, and the pre-composite blank passes under it to receive high-frequency ultrasonic puncture treatment.

[0072] The cold rolling unit 6 includes a pair of coolable rolls for cold rolling and shaping the pre-composite blank after ultrasonic needle punching and bonding to obtain the finished composite nonwoven fabric.

[0073] The winding device 7 is used to collect the finished product by collecting the final manufactured composite nonwoven fabric roll at a constant tension.

[0074] Example 3

[0075] Thirdly, this application provides a composite nonwoven fabric prepared by the processing method of Example 2. This composite nonwoven fabric comprises at least two fiber webs or functional membrane layers. Its structural feature is that adjacent layers are bonded together through three-dimensionally dispersed bonding points formed by ultrasonic melting and solidification of hot-melt polymer powder. The bonding points are discontinuously distributed in a dotted and / or columnar three-dimensional pattern. Furthermore, under the powerful mechanical vibration and puncture action of ultrasonic needle punching, a large number of fibers from adjacent different fiber webs are violently entangled, interwoven, and embedded within and around the bonding points, forming a composite interface structure that synergistically enhances the chemical bonding of the molten powder and the mechanical interlocking of the fiber entanglement. This effectively improves the material's extremely high interlayer peel strength, tear resistance, and structural integrity. Simultaneously, due to the discontinuous distribution of the bonding points and the avoidance of overall heating and compaction, the original bulkiness, softness, elasticity, and excellent air permeability and moisture permeability of each component material are maintained to the maximum extent, achieving a balance between high strength and high comfort. Moreover, because no chemical adhesives are added throughout the entire process, biocompatibility and environmental friendliness are further improved.

[0076] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0077] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for processing composite nonwoven fabrics, characterized in that, include: S1: Electrostatic treatment, electrostatic treatment is performed on the first fiber web layer to give its surface a static charge of the first polarity; S2: Powder spraying, spraying hot-melt polymer powder onto the surface of the second fiber mesh layer; S3: Layering and adsorption, the second fiber web layer is stacked with the first fiber web layer, and the hot-melt polymer powder is attracted and transferred to the surface of the first fiber web layer through electrostatic adsorption to form a pre-composite preform. S4: Ultrasonic needle punching composite, the pre-composite blank is passed through an ultrasonic needle punching device, the needle of the ultrasonic needle punching device vibrates under ultrasonic action and reciprocates to puncture the pre-composite blank following the feeding process. S5; Cold rolling curing: The pre-composite preform after ultrasonic needle punching is cold rolled and shaped to obtain the finished composite nonwoven fabric.

2. The processing method according to claim 1, characterized in that, In step S1, the first fiber web layer is electrostatically treated using corona discharge or a contact electrostatic generator to make its surface potential reach 1-20kV.

3. The processing method according to claim 1, characterized in that, In step S2, the hot-melt polymer powder is selected from one or a mixture of several of the following: copolyamide (Co-PA), copolyester (Co-PES), thermoplastic polyurethane (TPU), polyethylene (PE), or ethylene-vinyl acetate copolymer (EVA).

4. The processing method according to claim 1, characterized in that, In step S2, the particle size range of the hot-melt polymer powder is 1-100 μm.

5. The processing method according to claim 1, characterized in that, Step S2 further includes: electrostatically treating the hot-melt polymer powder to give the hot-melt polymer powder a second polarity opposite to the first polarity.

6. The processing method according to claim 1, characterized in that, Step S3 further includes: introducing a functional film layer, wherein the precomposite preform is composed of the first fiber mesh layer, the second fiber mesh layer and the functional film layer, and the hot-melt polymer powder is located between any two layers or simultaneously at multiple interlayer interfaces.

7. The processing method according to claim 1, characterized in that, In step S4, the ultrasonic frequency of the ultrasonic acupuncture device is 20-100kHz, and the power is 100-3000W; the puncture density of the needle is 10-200 punctures / cm², and the puncture depth is 1-20mm.

8. The processing method according to claim 1, characterized in that, In step S5, the surface temperature of the cooling roll is 5-25℃, and the rolling pressure is 10-200N / mm.

9. A composite nonwoven fabric processing apparatus for implementing the processing method according to any one of claims 1-8, characterized in that, Including those arranged sequentially along the processing direction: Unwinding device (1) is used to flatten and convey the fiber web layers; The electrostatic generator (2) is set along the path of the first fiber mesh layer (11) and is used to electrostatically treat the first fiber mesh layer so that its surface has a first polarity of static charge, and to electrostatically treat the hot melt polymer powder so that the hot melt polymer powder has a second polarity of static charge opposite to the first polarity. The powder spraying device (3) is set along the path of the second fiber mesh layer (12) and is used to spray hot-melt polymer powder onto the surface of the second fiber mesh layer. The lamination device (4) is used to laminate the second fiber web layer with the first fiber web layer. Through electrostatic adsorption, the hot-melt polymer powder is attracted and transferred to the surface of the first fiber web layer to form a pre-composite preform. An ultrasonic needle-piercing device (5) is used to make the needle vibrate under ultrasonic action and pierce the pre-composite blank; The cold rolling device (6) includes a pair of coolable rolls for cold rolling and shaping the pre-composite blank after ultrasonic needle punching to obtain the finished composite nonwoven fabric. The winding device (7) is used to collect the finished product.

10. A composite nonwoven fabric, prepared by the processing method according to any one of claims 1-8, characterized in that, The composite nonwoven fabric includes at least two layers of fiber webs, and the adjacent two layers of fiber webs are bonded together by three-dimensionally dispersed bonding points formed by hot-melt polymer powder. The bonding points are distributed in a discontinuous three-dimensional distribution of dots and / or columns, and there are entangled fibers from adjacent fiber webs inside and around the bonding points.

Images