Composite drain board based on ultrasonic welding and preparation method thereof

Abstract

The invention provides a composite drainage plate based on ultrasonic welding. The composite drainage plate comprises a bottom plate provided with a boss array and a geotechnical cloth layer. Wherein the surface of the geotechnical cloth layer is provided with polyester fibers, the polyester fibers are partially embedded into the boss array through ultrasonic welding to form an occlusion structure, and the embedding length of the polyester fibers is 0.3-0.8 mm. The invention further provides a method for preparing the composite drain board.

Description

Technical Field

[0001] This disclosure relates to the field of drainage materials technology in geotechnical engineering, and in particular to a composite drainage board structure and manufacturing method prepared by ultrasonic welding process. Background Technology

[0002] Composite drainage boards, as a key drainage material in geotechnical engineering, typically consist of a high-density polyethylene (HDPE) shaped base plate and a polyester (PET) geotextile filter layer. The HDPE base plate forms the main drainage channel through its raised surface structure, while the PET geotextile serves to filter sediment and prevent channel blockage.

[0003] Traditional composite drainage boards primarily employ adhesive bonding or hot-melt pressing processes to bond the two layers of materials. However, due to significant differences in the physicochemical properties of HDPE and PET, such as melting point, modulus, and surface energy, their interfacial bonding suffers from inherent structural disadvantages, leading to numerous technical defects in existing composite processes. On one hand, while adhesive bonding processes (using adhesives such as EVA and PU) are widely used, the adhesive layer is prone to aging, resulting in a sharp decline in peel strength and poor weather resistance. Simultaneously, adhesives can penetrate and clog the pores of the geotextile, severely impairing its permeability. Furthermore, solvent-based adhesives pose environmental risks such as excessive volatile organic compound (VOC) emissions. On the other hand, while hot-melt pressing avoids the use of adhesives, it requires overall heating to high temperatures, resulting in extremely high energy consumption. The heat also causes the PET fiber molecular chains to disorient, significantly reducing their breaking strength. Additionally, the limited melt flow of HDPE restricts the actual effective bonding area and results in insufficient bonding strength. In addition, although there have been attempts to improve the geotextile through surface modification or fiber melting, these methods have all resulted in new problems such as rapid decline in effectiveness, damage to the open porosity of the geotextile, or introduction of low-temperature brittleness, and have failed to fundamentally resolve the contradictions.

[0004] In summary, traditional composite drainage board manufacturing technologies struggle to simultaneously achieve multiple objectives, including ensuring the strength of component materials, improving production efficiency, and reducing energy consumption. Therefore, developing a novel composite material that simultaneously achieves reliable interfacial bonding, does not damage the properties of material components, and is environmentally friendly is of great significance for improving the long-term stability of drainage board projects and promoting the green and low-carbon development of the industry. Summary of the Invention

[0005] In view of this, in order to solve at least one technical problem in related technologies and other aspects, this disclosure proposes a composite drainage board based on ultrasonic welding, including a base plate with an array of protrusions and a geotextile layer. The surface of the geotextile layer has polyester fibers, which are partially embedded in the protrusion array by ultrasonic welding to form an interlocking structure, wherein the embedding length of the polyester fibers is 0.3~0.8 mm.

[0006] According to embodiments of this disclosure, the embedding length accounts for 30% to 60% of the total length of the polyester fiber.

[0007] According to embodiments of this disclosure, the basis weight of the geotextile layer is 100~300 g / m². 2 .

[0008] According to embodiments of this disclosure, the height of each boss in the boss array is 0.8~2.0cm.

[0009] According to embodiments of this disclosure, the melting point of the base plate is 120~130℃, and the melting point of the geotextile layer is 250~260℃.

[0010] In another aspect of this disclosure, a method for preparing the aforementioned composite drainage board is also provided, comprising:

[0011] An ultrasonic welding head is used to emit ultrasonic waves onto the surface of each boss in the boss array of the base plate, so that a melting zone is formed on the surface of each boss, and a geotextile layer with polyester fibers is used to cover the melting zone.

[0012] Pressure is applied to the geotextile layer to partially embed the polyester fibers into the molten zone, forming an interlocking structure.

[0013] According to embodiments of this disclosure, in the process of forming a molten zone on the surface of the boss array of the base plate by ultrasonic welding:

[0014] The ultrasonic welding time is 0.2~0.8s, and the power density of ultrasonic welding is 300~500W / cm³. 2 The ratio of the effective area of ​​the ultrasonic welding head to the projected area of ​​the boss surface is (1.2~1.5):1, and the working frequency of ultrasonic welding is 10~50kHz.

[0015] According to embodiments of this disclosure, the temperature of the melting zone is 130~160°C, which is lower than the melting temperature of the polyester fiber.

[0016] According to embodiments of this disclosure, the pressure applied to the geotextile layer is 0.2~0.5 MPa.

[0017] According to embodiments of this disclosure, in the process of applying pressure to the geotextile layer: the pressure holding time is 1.2 to 1.8 times the ultrasonic welding time.

[0018] According to embodiments of this disclosure, ultrasonic welding is used to directly embed polyester fibers into the base plate boss array, creating a mechanical interlocking effect and forming an interlocking structure. This significantly enhances the interfacial bonding force between the geotextile layer and the base plate, effectively resisting interlayer delamination and thus improving the overall structural stability and durability of the composite drainage board. Simultaneously, ultrasonic welding facilitates precise application to the bonding interface, avoiding large-area thermal damage to the polyester fibers of the geotextile layer and the base plate material. This preserves the original fiber structure and porosity of the geotextile, maintaining the filtration and permeability performance of the composite drainage board and ensuring long-term unobstructed drainage channels. Specifically, the embedding length of the polyester fibers is limited, optimizing the depth range of the mechanical interlocking, thereby ensuring sufficient anchoring strength while preventing fiber damage or base plate structural destruction due to excessive embedding. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of the composite drainage board in the direction perpendicular to the base plate in an embodiment of this disclosure;

[0020] Figure 2 This is a schematic diagram illustrating the principle of using an ultrasonic welding head to emit ultrasonic waves onto the surface of each boss in the boss array of the base plate in this embodiment of the disclosure.

[0021] Figure 3 This is a physical image of the composite drainage board in an embodiment of this disclosure;

[0022] Figure 4 These are comparative test images of the composite drainage boards prepared in Example 1 and the comparative example of this disclosure, where A is the peeling and damage test image of the composite drainage board prepared in Example 1, and B is the peeling and damage test image of the composite drainage board prepared in the comparative example.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1-Base plate; 11-Boss; 2-Geotextile layer; 3-Interlocking structure; 4-Melting zone; 5-Ultrasonic welding head. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0026] The endpoints and any values ​​of the ranges disclosed in this disclosure are not limited to the precise ranges or values, and such ranges or values ​​should be understood to include values ​​close to such ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in this disclosure.

[0027] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0028] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0029] In this disclosure, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0030] In the description of this disclosure, it should be understood that the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and do not indicate or imply that the subsystem or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0031] Throughout the accompanying drawings, identical elements are represented by the same or similar reference numerals. Conventional structures or configurations have been omitted where they may cause confusion in understanding this disclosure. Furthermore, the shapes, dimensions, and positional relationships of the components in the drawings do not reflect their actual size, scale, or actual positional relationships. Additionally, any reference symbols enclosed in parentheses should not be construed as limiting this disclosure.

[0032] Similarly, to simplify this disclosure and aid in understanding one or more of the various aspects of the disclosure, in the above description of exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. The use of terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refers to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present disclosure. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0033] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of a person skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this disclosure.

[0034] In the process of implementing this disclosure, it was discovered that by utilizing the difference in melting points between the base plate (HDPE (high-density polyethylene)) and the geotextile layer (polyester material), and by applying instantaneous and localized precise heating to the low-melting-point HDPE only at the interface to melt it, while maintaining the structural stability of the higher-melting-point polyester fibers, a strong bond can be achieved through physical encapsulation, thus avoiding the inherent defects of chemical adhesives and overall thermal damage. Based on this, this disclosure introduces ultrasonic welding technology, utilizing its characteristics of energy localization and instantaneous action to selectively melt the surface layer of the HDPE protrusions, and embed solid polyester fibers into them under pressure. After cooling, the polyester fibers are firmly anchored by the solidified HDPE, forming a micro-mechanical interlocking structure.

[0035] Specifically, by calculating the standard thermodynamic formula for heat absorption by the material, and utilizing the material melting point difference (ΔT≥120℃) and the localization coupling effect of ultrasonic energy, the following equation (1) is obtained:

[0036]

[0037] in:

[0038] Q: Ultrasonic energy (unit: J)

[0039] ρ: HDPE density (0.95 g / cm³) 3 (ASTM D792)

[0040] c p Specific heat capacity of HDPE (2.3 J / g·K, ISO 11357)

[0041] d: Thickness of the molten zone (50-100 μm, calculated value)

[0042] A: Welding head working area (mm) 2 )

[0043] When ultrasound propagates through a material, some of its mechanical energy is converted into heat energy, causing the material temperature to rise (ΔT). Ultrasonic power is related to energy transfer, but equation (1) focuses on the thermal effect. This formula assumes that the heat is uniformly distributed and ignores the heat loss (such as convection and radiation) and uneven energy distribution that may exist in actual ultrasonic welding.

[0044] Figure 1 This is a cross-sectional view of the composite drainage board in the direction perpendicular to the base plate in an embodiment of this disclosure.

[0045] This disclosure proposes a composite drainage board based on ultrasonic welding, such as Figure 1 As shown, the structure includes a base plate 1 with an array of protrusions and a geotextile layer 2. The surface of the geotextile layer 2 has polyester fibers, which are partially embedded in the array of protrusions by ultrasonic welding to form an interlocking structure 3. The embedding length of the polyester fibers is 0.3~0.8mm.

[0046] According to embodiments of this disclosure, ultrasonic welding is used to directly embed polyester fibers into the protrusion array of the base plate 1, creating a mechanical interlocking effect and forming an interlocking structure 3. This significantly enhances the interfacial bonding force between the geotextile layer 2 and the base plate 1, effectively resisting interlayer delamination and thus improving the overall structural stability and durability of the composite drainage board. Simultaneously, ultrasonic welding facilitates precise application to the bonding interface, avoiding large-area thermal damage to the polyester fibers of the geotextile layer 2 and the material of the base plate 1. This preserves the original fiber structure and porosity of the geotextile, maintaining the filtration and permeability performance of the composite drainage board and ensuring long-term unobstructed drainage channels. Specifically, the embedding length of the polyester fibers is limited, optimizing the depth range of the mechanical interlocking, thereby ensuring sufficient anchoring strength while preventing fiber damage or structural destruction of the base plate 1 due to excessive embedding.

[0047] Specifically, the term "interlocking structure" as used in this disclosure means that when the surface of the protrusion array is in a molten state, polyester fibers penetrate into the surface of the geotextile layer 2. After the molten protrusion array cools and solidifies, some polyester fibers are embedded into the protrusion array, thereby forming an "interlocking structure (or interlocking structure)," which increases the bonding strength between the geotextile layer 2 and the base plate 1, making the two difficult to separate.

[0048] In some specific embodiments, the base plate 1 is made of high-density polyethylene (HDPE) and forms the main drainage channel; the geotextile layer 2 is made of polyester (PET) and serves to filter silt and prevent channel blockage. Water that permeates through the geotextile layer flows out through the gaps formed by the convex strip array. The physical and chemical properties of the two layers are fundamentally different.

[0049] In some specific embodiments, the peel strength of the composite drainage board is not less than 3.5 N / mm, and the permeability coefficient retention rate is >95%.

[0050] According to embodiments of this disclosure, the embedding length accounts for 30% to 60% of the total length of the polyester fiber.

[0051] According to embodiments of this disclosure, the embedded proportion range is beneficial in ensuring that sufficient length of polyester fiber is anchored by HDPE, so that the interlocking structure 3 has sufficient bonding strength; at the same time, it also ensures that a portion of the polyester fiber segment remains free, thereby maintaining the overall flexibility and permeability integrity of the geotextile. When the polyester fiber embedding is too short, polyester fiber pull-out is likely to occur, resulting in weak interfacial bonding and weak stability of the interlocking structure 3; if the polyester fiber embedding is too long, it may excessively damage the continuity and mechanical properties of the polyester fiber, and may cause excessively high local hardness of the interlocking structure 3, affecting the overall flexibility and deformation capacity of the geotextile layer 2.

[0052] According to embodiments of this disclosure, the basis weight of geotextile layer 2 is 100~300 g / m². 2 .

[0053] According to embodiments of this disclosure, the basis weight range ensures that the geotextile layer 2 has sufficient polyester fiber density and thickness, allowing enough polyester fibers to be embedded in the molten HDPE during ultrasonic welding. If the basis weight is too low, the geotextile layer 2 will be too thin and the fiber quantity insufficient, resulting in limited polyester fibers available for forming mechanical interlocking, sparse bonding points, insufficient overall bonding strength, and easily compromised filtration and protection functions. If the basis weight is too high, it not only increases unnecessary material costs but may also reduce the structural stability of the composite drainage board.

[0054] According to embodiments of this disclosure, the height of each boss 11 in the boss array is 0.8~2.0cm.

[0055] According to the embodiments of this disclosure, the height range of the boss 11 is beneficial to balancing the structural strength of the composite drainage board and appropriate drainage space. If the height of the boss 11 is too low, the rigidity of the boss 11 is poor, the molten zone 4 during ultrasonic welding is small, it is difficult to form an effective mechanical interlocking structure, and the drainage space is easily squeezed and blocked; if the height of the boss 11 is too high, the overall rigidity of the base plate 1 decreases, it is easy to bend and deform, which will have an adverse effect on the pressure uniformity during pressure application and the flatness of the drainage board.

[0056] According to embodiments of this disclosure, the melting point of the base plate 1 is 120~130℃, and the melting point of the geotextile layer 2 is 250~260℃.

[0057] According to embodiments of this disclosure, the base plate 1 and the geotextile layer 2 have a significant melting point difference, which is the physical basis for the successful implementation of ultrasonic welding. Under this melting point difference, the applied ultrasonic energy can be precisely controlled to only momentarily melt the surface layer of the protrusions 11 in the base plate 1, while the polyester fibers of the geotextile layer 2 remain solid. This ensures a strong mechanical interlock while avoiding strength and structural damage to the geotextile's polyester fibers due to thermal melting and orientation.

[0058] Figure 2 This is a schematic diagram illustrating the principle of using an ultrasonic welding head 5 to emit ultrasonic waves onto the surface of each boss 11 of the boss array on the base plate 1 in this embodiment of the present disclosure.

[0059] In another aspect of this disclosure, a method for preparing the aforementioned composite drainage board is also provided, comprising:

[0060] like Figure 2 As shown, ultrasonic waves are emitted from the ultrasonic welding head 5 onto the surface of each boss 11 of the boss array on the base plate 1, so that a melting zone 4 is formed on the surface of each boss 11, and the geotextile layer 2 with polyester fiber is covered with the melting zone 4.

[0061] Pressure is applied to the geotextile layer 2 to partially embed the polyester fibers into the melting zone 4, forming an interlocking structure 3.

[0062] According to embodiments of this disclosure, the preparation method proposed in this disclosure achieves precise and low-damage heterogeneous material composites. First, ultrasonic energy is selectively and instantaneously applied to the surface of the HDPE boss 11 to form a molten zone 4. This process involves highly concentrated energy and an extremely short duration, achieving precise local heating and reducing thermal damage. Second, by applying pressure in the molten state, solid polyester fibers are embedded into the melt, followed by cooling and solidification. This process directly forms a robust physical-mechanical interlocking structure. This bonding method does not rely on any chemical adhesives, thereby avoiding the risks of adhesive layer aging and peeling, and VOC emissions.

[0063] According to embodiments of this disclosure, in the process of forming a molten zone 4 on the surface of the boss 11 of the boss array of the base plate 1 by ultrasonic welding:

[0064] The ultrasonic welding time is 0.2~0.8s, and the power density of ultrasonic welding is 300~500W / cm³. 2 The ratio of the effective area of ​​the ultrasonic welding head to the projected area of ​​the surface of the boss 11 is (1.2~1.5):1, and the working frequency of ultrasonic welding is 10~50kHz.

[0065] According to embodiments of this disclosure, by coordinating the control of ultrasonic welding time, power density, and effective area ratio, instantaneous and precise melting of the HDPE boss 11 surface layer is achieved. This provides sufficient energy in a very short time, ensuring the formation of a molten layer with suitable thickness and fluidity, creating conditions for polyester fiber embedding. Simultaneously, it strictly limits the range of the heat-affected zone, avoiding energy waste and thermal damage to the substrate. Here, "effective area of ​​the ultrasonic welding head" refers to the actual area where the welding head contacts and transfers energy to the boss 11; "projected area of ​​the boss 11 surface" refers to the projected area of ​​the top of the boss 11 on a horizontal plane. Controlling the former to be slightly larger than the latter helps ensure that ultrasonic energy completely covers the top of the boss 11, avoiding uneven melting due to alignment deviations.

[0066] In some specific embodiments, the ultrasonic welding head area calibration model is ISO17662.

[0067] According to embodiments of this disclosure, the temperature of the melting zone 4 is 130~160°C, which is lower than the melting temperature of the polyester fiber.

[0068] According to embodiments of this disclosure, limiting the temperature of the melting zone 4 helps ensure that the HDPE can melt fully and have good fluidity, thereby encapsulating the polyester fibers, while avoiding melting or heat damage to the polyester fibers.

[0069] In some specific embodiments, the melt flow rate of the base plate 1 is 0.5-2.0 g / 10 min (190℃ / 2.16 kg).

[0070] In some specific embodiments, the temperature of the molten zone 4 is determined by infrared thermometry, and the infrared thermometry device is a Hima AR320.

[0071] According to embodiments of this disclosure, the pressure applied to the geotextile layer 2 is 0.2~0.5 MPa.

[0072] According to embodiments of this disclosure, this pressure range is beneficial for effectively embedding polyester fibers into the HDPE in the molten zone 4, thereby forming a sufficiently deep interlocking structure 3; at the same time, it avoids excessive pressure causing the HDPE in the molten zone 4 to be excessively squeezed out or the polyester fibers to be damaged, thereby ensuring the integrity of the interlocking structure 3 and that the geotextile itself is not damaged.

[0073] According to an embodiment of this disclosure, in the process of applying pressure to the geotextile layer 2: the pressure holding time is 1.2 to 1.8 times the ultrasonic welding time.

[0074] According to embodiments of this disclosure, controlling the holding time allows the HDPE in the molten zone 4 to have sufficient time to fully encapsulate the embedded polyester fibers, while ensuring that it can complete preliminary curing and shaping under pressure, thereby forming a stable and uniform interlocking structure 3.

[0075] In some specific embodiments, after the interlocking structure 3 is formed, cooling and shaping are required. This can be achieved through air cooling, with a cooling rate ≥15℃ / s. An industrial electric fan can be used for cooling; a Diamond brand high-powered fan FS-65 is a suitable model.

[0076] It should be noted that the described embodiments are merely some, not all, of the embodiments disclosed herein. Other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without inventive effort are all within the scope of protection of this disclosure.

[0077] Example 1

[0078] 1. Material preparation and pretreatment

[0079] Commercially available high-density polyethylene raw material was selected, and an array of boss base plates 1 with a boss height of 1.2 mm and a center distance of 10 mm was prepared by a twin-screw plastic extrusion molding machine.

[0080] Short-fiber needle-punched polyester material was selected as geotextile layer 2, with an average thickness of 0.8 mm. Before use, it was equilibrated for 24 hours under a standard environment of 23±2℃ and 50±10% relative humidity.

[0081] 2. Configuration of Ultrasonic Welding System

[0082] The core components of the ultrasonic welding system include:

[0083] Ultrasonic generator: Shanghai Dehuilian, model 15-20K, maximum output power of 1500W, automatic tracking and display of real-time frequency, amplitude step function, 1% accuracy.

[0084] Ultrasonic welding head: Shanghai Dehuilian, made of imported alloy steel, with a 5mm×10mm rectangular plane on the working end face.

[0085] Pneumatic pressurization system: provides adjustable pressure with an accuracy of ±0.02MPa.

[0086] Infrared thermometer: Hima AR320, used for real-time monitoring of the temperature field in the welding area.

[0087] 3. Welding and stacking positioning: Lay the geotextile layer 2 flat on the protrusion 11 of the base plate 1, ensuring no wrinkles.

[0088] 4. Parameter Setting and Welding: The ultrasonic generator output power is set to 1200W, and the calculated power density is approximately 400W / cm³. 2 Set the air pressure system pressure to 0.3 MPa; set the welding time to 0.5 s.

[0089] 5. Start the equipment, and the ultrasonic welding head descends and aligns with the predetermined welding area. Under the action of ultrasound for 0.5 seconds, the top of the HDPE boss 11 instantly absorbs energy and melts to form a molten pool. Infrared thermal imaging shows that the surface temperature of HDPE rises to about 150°C within 0.4 seconds, while the temperature of the back side of geotextile layer 2 remains below 80°C, far below its glass transition temperature.

[0090] 6. Compression and Holding Pressure: Immediately after the ultrasonic treatment, the system enters the holding pressure stage, maintaining a pressure of 0.3 MPa for 0.7 seconds. During this stage, the molten HDPE flows under pressure and encapsulates the PET fibers in contact with it.

[0091] 7. Cooling and Shaping: Remove the pressure and welding head, and the molten HDPE will cool and solidify naturally in ambient air (cooling rate of about 20℃ / s), forming a strong interlocking structure with the PET fibers.

[0092] Figure 3 This is a physical image of the composite drainage board in an embodiment of this disclosure.

[0093] The composite drainage board prepared in Example 1 is as follows: Figure 1 As shown.

[0094] Test Example 1: Interlayer Peel Strength Test

[0095] The composite drainage board prepared in Example 1 was tested on a universal testing machine (Dongguan Kejian KJ1065A) according to ASTM D903 standard.

[0096] Its average peel strength was measured to be 4.2 N / mm.

[0097] Observation of the damaged surface showed that the damage mainly occurred at the broken PET fibers, rather than at the bonding interface, proving that the interfacial bonding strength of the interlocking structure 3 was higher than the strength of the geotextile itself.

[0098] Test Example 2: Vertical Permeability Coefficient Test

[0099] According to GB / T17633 standard, the composite drainage board prepared in Example 1 was tested using a GDSHYRD-2 constant head permeameter.

[0100] Its vertical permeability coefficient was measured to be 2.7 × 10⁻⁶. -1 cm / s, compared with the raw material geotextile (2.9×10 cm / s).-1 Compared to (cm / s), it maintained 93% permeability, proving that the welding process did not damage the filtration performance of the geotextile.

[0101] Example 2

[0102] The preparation method of the composite drainage board in this embodiment is the same as or similar to that in Embodiment 1, but this embodiment specifically demonstrates the optimal application mode under normal conditions.

[0103] The base plate 1 is made of Sinopec Yanchang Petrochemical (brand name: 6094), with a melt flow rate (MFR) of 1.0 g / 10 min (190℃ / 2.16 kg, test standard ASTM D1238); the geotextile layer 2 is made of geotextile with a basis weight of 200 g / m. 2 The short-fiber needle-punched polyester geotextile (Shandong Xinghe) has an average thickness of 0.8 mm.

[0104] The ultrasonic welding process is as follows: ultrasonic power: 1200W (power density approximately 400W / cm²), welding time: 0.5s, welding pressure: 0.3MPa, and holding time: 0.7s.

[0105] Tests showed that the average interlaminar peel strength of the composite drainage board prepared in Example 2 was 4.2 N / mm, with the failure mode being the breakage of PET fibers. The composite strength was higher than the strength of the material itself; its vertical permeability coefficient was 2.7 × 10⁻⁶. -1 cm / s.

[0106] Application Example 1: Application in high-altitude and cold environments

[0107] This application example aims to verify the reliability of the composite drainage board prepared according to this disclosure in low-temperature environments, focusing on solving the problem of low-temperature brittleness of polymer materials.

[0108] In Example 1, 3% of ethylene-vinyl acetate copolymer (EVA, brand name UL00528, Beijing Chemical) was blended into the HDPE raw material as an antifreeze and toughening modifier, and its MFR was adjusted to 0.9 g / 10 min.

[0109] The samples were placed in a -30℃ low temperature environment for 24 hours before testing. The average low temperature peel strength was 3.5 N / mm. Low temperature brittleness test was performed on the bonding interface, and no cracking or peeling was observed.

[0110] Application Example 2: High-frequency rapid welding

[0111] This application example aims to explore how to achieve more precise and faster welding by increasing the ultrasonic frequency to meet the demands of high-efficiency production.

[0112] The parameters of the ultrasonic welding process were adjusted as follows: Ultrasonic power: 1500W (power density approximately 500W / cm³). 2 The welding time is 0.3s, the welding pressure is 0.3MPa, and the holding time is 0.5s. The high-frequency welding head has a smaller effective area of ​​3mm × 8mm, resulting in more concentrated energy.

[0113] The average interlayer peel strength was measured to be 3.8 N / mm. Although slightly lower than that of the composite drainage board prepared in Example 1, it is still far superior to the level of traditional processes and meets the requirements of engineering applications. At the same time, due to the reduction of the welding cycle by about 40%, its production efficiency is improved, and the theoretical production speed of the production line can be increased by 30%.

[0114] Comparative Example

[0115] In this comparative example, the composition of the base plate 1 and the geotextile layer 2 is the same as in Example 1, and the interlayer bonding is achieved using a hot melt adhesive process. The required EVA hot melt adhesive is Yuhong's own EVA hot melt adhesive, with a melt viscosity of 15000 cps (170℃) and a softening point of 72℃; and the hot melt adhesive coating machine is ChemInstruments, model HICL-2000, equipped with a precision slot coating head and a double-roller laminating machine.

[0116] The specific process is as follows:

[0117] 1. Adhesive preparation and coating: EVA hot melt adhesive granules are melted in a glue tank at 160℃. The molten adhesive is then coated using a coating machine at a rate of 80g / m³. 2 The coating amount is evenly applied to the surface of the boss 11 on the base plate 1.

[0118] 2. Pre-composite: Immediately cover the geotextile layer 2 onto the base plate 1 coated with adhesive, and perform preliminary pressing using a composite roller.

[0119] 3. Curing and shaping: Cool the pre-composite semi-finished product to allow the EVA adhesive layer to fully cure, and finally obtain the composite drainage board.

[0120] The performance of the composite drainage boards prepared in Example 1 and the comparative example was tested, and the specific results are shown in Table 1 below.

[0121] Table 1:

[0122]

[0123] Figure 4 These are comparative test images of the peeling and damage tests of the composite drainage boards prepared in Embodiment 1 and the comparative example of this disclosure.

[0124] As shown in Table 1 and Figure 4As shown, a quantitative comparison of the composite drainage boards prepared in Example 1 and the comparative example reveals that ultrasonic welding technology exhibits comprehensive advantages over traditional EVA adhesive bonding. In terms of core bonding performance, the initial peel strength of ultrasonic welding is 2-3 times that of EVA adhesive bonding (1.8 N / mm). In terms of functionality, the permeability coefficient of the ultrasonically welded sample is essentially consistent with that of the adhesive-bonded sample, maintaining the geotextile's permeability. In the manufacturing process, ultrasonic welding achieves zero VOC emissions, and the unit energy consumption is reduced by more than 40% compared to the EVA process. In summary, ultrasonic welding achieves improvements over traditional adhesive bonding processes in terms of strength, functional retention, and environmental efficiency.

[0125] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A composite drainage board based on ultrasonic welding, comprising: The base plate has an array of bosses on its surface; The geotextile layer has polyester fibers on its surface. The polyester fibers are partially embedded in the protrusion array by ultrasonic welding to form an interlocking structure. The embedding length of the polyester fibers is 0.3~0.8mm.

2. The composite drainage board according to claim 1, wherein, The embedding length accounts for 30% to 60% of the total length of the polyester fiber.

3. The composite drainage board according to claim 1, wherein, The geotextile layer has a basis weight of 100~300 g / m². 2 .

4. The composite drainage board according to claim 1, wherein, The height of each boss in the boss array is 0.8~2.0cm.

5. The composite drainage board according to claim 1, wherein, The melting point of the base plate is 120~130℃, and the melting point of the geotextile layer is 250~260℃.

6. A method for preparing a composite drainage board as described in any one of claims 1 to 5, comprising: An ultrasonic welding head is used to emit ultrasonic waves onto the surface of each boss in the boss array of the base plate, so that a melting zone is formed on the surface of each boss, and a geotextile layer with polyester fibers is covered to the melting zone. Pressure is applied to the geotextile layer to partially embed the polyester fibers into the molten zone, forming an interlocking structure.

7. The method according to claim 6, wherein, In the process of forming a molten zone on the surface of the boss array of the base plate by ultrasonic welding: The ultrasonic welding time is 0.2~0.8s, and the power density of ultrasonic welding is 300~500W / cm³. 2 The ratio of the effective area of ​​the ultrasonic welding head to the projected area of ​​the boss surface is (1.2~1.5):1, and the working frequency of ultrasonic welding is 10~50kHz.

8. The method according to claim 7, wherein, The temperature of the melting zone is 130~160℃, which is lower than the melting temperature of the polyester fiber.

9. The method according to claim 7, wherein, During the pressure application to the geotextile layer, the pressure is 0.2~0.5 MPa.

10. The method according to claim 9, wherein, In the process of applying pressure to the geotextile layer: the pressure holding time is 1.2 to 1.8 times the ultrasonic welding time.

Images