Water retaining film with anti-electromagnetic interference function, preparation method and intelligent automobile door system

Abstract

The invention discloses a water retaining film with an anti-electromagnetic interference function, a preparation method and an intelligent automobile door system, and the water retaining film comprises a doped conductive coating layer which is coated on the surface of a film main body; the at least one reinforcing structure is arranged at the wire harness threading through hole of the film main body, a reinforcing plastic flange seat ring and a reinforcing plastic cover plate respectively cover the wire harness threading through hole from two sides of the film main body, and the reinforcing structure and the film main body are welded and fixed into a whole; the at least one waterproof, moisture-permeable and breathable unit is arranged on the film main body; and the waterproof, moisture-permeable and air-permeable unit comprises a moisture-removing and air-permeable hole formed in the film main body, and an ePTFE waterproof and air-permeable film patch covering and sealing the moisture-removing and air-permeable hole. By means of the mode, through the innovative multi-layer composite structure, the three technical problems of electromagnetic interference, rainwater leakage and internal condensation of the intelligent vehicle door are comprehensively solved, the reliability and safety of the system are remarkably improved, and the service life of the system is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of water-retaining membranes, and in particular to a water-retaining membrane with anti-electromagnetic interference function, a preparation method thereof, and an intelligent car door system having the water-retaining membrane. Background Technology

[0002] With the rapid advancement of automotive intelligence, intelligent car doors (electric side door opening systems) have become standard equipment in high-end models. This system integrates numerous sophisticated electronic components such as door actuators, electric door locks, radar, and ECUs, significantly improving ease of use and user experience. However, the increasingly complex in-vehicle electronic environment (such as in-vehicle radar, 5G modules, and high-voltage motors) generates strong electromagnetic noise, creating a complex electromagnetic interference (EMI) environment. According to data from the International Electromagnetic Compatibility Association, the bit error rate of unprotected ECU modules can surge by 300% in strong electromagnetic environments. This poses a serious threat to intelligent car doors that rely on precise electrical signal control, potentially leading to safety hazards such as accidental opening or locking of the door, or malfunction in emergency situations.

[0003] At the same time, the physical protection of intelligent car door systems also faces challenges. Traditional automotive water shields mostly use non-breathable materials such as PE, EVA, or XPE, which have two major drawbacks: First, the wiring harness through-hole area is prone to fatigue cracking under driving vibration, causing rainwater to seep into the "electrical side space" inside the door (i.e., the area between the water shield and the door sheet metal); second, the non-breathable material will seal in high-temperature and high-humidity air inside, and when the ambient temperature changes, condensation and fogging are prone to occur on the surface of internal electrical components, causing random faults such as electrical short circuits and grounding.

[0004] In existing technologies, although door wiring harnesses employ measures such as twisted-pair cables and anti-magnetic wrapping layers for local electromagnetic protection, and waterproofing of vias is achieved with rubber plugs, these are all decentralized solutions targeting the wiring harness itself and lack a systematic approach. Currently, there is no effective overall electromagnetic shielding solution for the entire electrical side space enclosed by the water-retaining membrane and the door sheet metal.

[0005] Therefore, inventing a water-repellent membrane that can overcome the above problems has become an urgent need to improve the reliability and safety of smart car doors. Summary of the Invention

[0006] The main technical problem solved by this invention is to provide an integrated water-blocking membrane that can achieve both physical waterproofing and anti-condensation at the physical level, as well as electromagnetic interference shielding, and an intelligent car door system with the water-blocking membrane, thereby improving the reliability and safety of the intelligent car door.

[0007] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is to provide a water-retaining membrane with anti-electromagnetic interference function, comprising:

[0008] The main body of the film is made of polymer film material;

[0009] A doped conductive coating layer is applied to the surface of the thin film substrate;

[0010] At least one reinforcing structure is disposed at the wire harness through-hole of the film body; the reinforcing structure includes a reinforcing plastic flange seat and a reinforcing plastic cover plate, the reinforcing plastic flange seat and the reinforcing plastic cover plate respectively cover the wire harness through-hole from both sides of the film body, and are welded and fixed to the film body as one piece by welding.

[0011] At least one waterproof, breathable and ventilated unit is disposed on the membrane body; the waterproof, breathable and ventilated unit includes a moisture-venting and venting hole opened on the membrane body, and an ePTFE waterproof and ventilated membrane patch covering and sealing the moisture-venting and venting hole;

[0012] An adhesive layer is coated on the other surface of the film body that is not coated with the doped conductive coating layer, preferably a butyl adhesive layer.

[0013] By integrating electromagnetic shielding, structural reinforcement, and waterproofing / breathability into a single water-retaining membrane product, a comprehensive solution is provided to address the dual technical challenges of waterproofing, condensation prevention, and interference resistance faced by smart car doors.

[0014] In a preferred embodiment of the present invention, the doped conductive coating layer is one of carbon-based conductive coatings, graphite conductive coatings, metal-based conductive coatings, nanotube conductive coatings, or metal oxide conductive coatings. Carbon-based and graphite coatings prioritize cost; metal-based coatings, such as nickel and copper, prioritize performance; nanotubes represent cutting-edge technology. These multiple options provide the technical solution with great flexibility and industrial adaptability, ensuring that suitable solutions can be found for vehicle models with different cost and performance requirements.

[0015] In a preferred embodiment of the present invention, the metallic conductive coating is a nickel-based conductive coating or a copper-based conductive coating that has undergone anti-oxidation treatment. Nickel powder has good chemical stability and is the preferred choice for balancing performance and cost; copper powder is inexpensive but easily oxidized, and anti-oxidation treatment ensures the long-term stability of the conductivity of copper powder in actual use.

[0016] In a preferred embodiment of the present invention, the surface resistivity of the doped conductive coating layer is ≤0.3Ω / 10cm. This threshold value is a threshold value to ensure the formation of effective electromagnetic shielding and to guarantee the shielding effect.

[0017] In a preferred embodiment of the present invention, the polymer film material is one of PE, EVA or XPE, and is further limited to a polymer material with common, flexible, waterproof and cost-controllable properties.

[0018] In a preferred embodiment of the present invention, the welding method is ultrasonic welding or hot-press welding. This ensures that the reinforcing structure and the film body are fused and fixed together, thereby obtaining optimal connection strength and long-term sealing reliability, which is the technical guarantee for realizing the reinforcing function.

[0019] In a preferred embodiment of the present invention, the ePTFE waterproof and breathable membrane patch is bonded to the moisture-wicking and breathable holes by a pressure-sensitive adhesive ring, which not only ensures the effective realization of the breathability function, but also prevents moisture from seeping in from the bonding edge, thus balancing functionality and sealing.

[0020] Another technical solution adopted by the present invention is: providing a method for preparing the water-retaining membrane with anti-electromagnetic interference function, comprising the following steps:

[0021] S1: Prepare thin film raw materials, doped conductive coating, reinforced plastic flange seat ring, reinforced plastic cover plate, ePTFE waterproof and breathable membrane patch, pressure-sensitive rubber ring and adhesive;

[0022] S2: Unwind the film, electrostatically or manually spray the doped conductive coating onto one surface, and after leveling and low-temperature drying and curing, form a conductive coating layer, then rewind for later use.

[0023] S3: Unwind the film with the conductive coating layer, die-cut it, and then perform vacuum forming;

[0024] S4: Die-cut wire harness through holes and moisture venting holes on the formed film body;

[0025] S5: Align the reinforcing plastic flange seat and the reinforcing plastic cover plate with the wire harness through-hole of the film body and fix them by welding.

[0026] S6: The ePTFE waterproof and breathable membrane patch is bonded to the moisture-wicking and breathable holes using a pressure-sensitive rubber ring;

[0027] S7: Apply a butyl adhesive layer to the surface of the film body that is not coated with a conductive coating layer, and cover it with release paper;

[0028] S8: Inspect and package the finished product.

[0029] Another technical solution adopted by the present invention is: to provide an intelligent car door system, including a metal door sheet metal, a door opening actuator, an electric suction door lock, a radar, an ECU, and a connecting wiring harness disposed thereon. The system is equipped with a water-blocking membrane with anti-electromagnetic interference function as described in any one of the present inventions. The water-blocking membrane is sealed and attached to the door sheet metal by its butyl adhesive layer. The doped conductive coating layer is in electrical contact with the door sheet metal, together forming an electromagnetic shielding cavity. The door opening actuator, the electric suction door lock, the radar, and the ECU are located in the shielding cavity.

[0030] In a preferred embodiment of the present invention, the connecting harness passes through the reinforcing structure in a sealed manner via a wire harness rubber plug, ensuring that the electromagnetic sealing and waterproofing of the shielding cavity are effective simultaneously under vehicle vibration conditions.

[0031] The beneficial effects of the present invention are as follows: By adding a doped conductive coating layer to the water-blocking membrane body and reliably connecting it with the metal door sheet metal, the present invention forms a closed shielding chamber, which effectively attenuates electromagnetic interference from internal and external components of the vehicle, provides a "clean" working environment for sensitive electronic components such as door actuators and ECUs, significantly reduces the signal error rate, and ensures the accuracy and reliability of intelligent door control commands.

[0032] The reinforcing structure of this invention ensures the mechanical strength and dynamic sealing of the wire harness through-hole area, fundamentally preventing rainwater leakage. The expanded polytetrafluoroethylene (ePTFE) microporous membrane achieves balanced convection between internal moisture and the external atmosphere, effectively eliminating internal condensation and providing a dry and stable internal environment for electrical components.

[0033] This invention innovatively integrates three major functions—electromagnetic shielding, waterproof sealing, and moisture-proof anti-condensation—into a single component. This not only simplifies the vehicle door assembly process but also comprehensively addresses potential risks in both electrical and environmental dimensions, achieving a multiplier effect on system safety. Especially in emergency situations (such as after a collision with strong electromagnetic interference accompanied by damp circuitry), this invention maximizes the normal operation of the intelligent door opening function, enhancing the reliability and safety of the intelligent vehicle door. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0035] Figure 1 This is a schematic diagram of a preferred embodiment of the water-blocking membrane with anti-electromagnetic interference function of the present invention;

[0036] Figure 2 yes Figure 1 The diagram shows a cross-sectional view of a water-retaining membrane with electromagnetic interference resistance. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0040] In the description of this invention, it should be noted that the terms "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0041] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0042] In this invention, unless otherwise expressly specified and limited, "above or below" a first feature may include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on" the first feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the first feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0043] Please see Figure 1 and Figure 2 .

[0044] Embodiment 1 of the present invention includes:

[0045] A water-blocking membrane 100 with anti-electromagnetic interference function is a core protective component of the automotive intelligent door system, integrating four major functions: electromagnetic shielding, waterproof sealing, structural reinforcement, and moisture permeability and anti-condensation.

[0046] The water-retaining membrane 100 includes:

[0047] The film body 101, serving as the structural substrate of the entire product, is made of a flexible and waterproof polymer film material, such as PE (polyethylene), EVA (ethylene-vinyl acetate copolymer), or XPE (chemically cross-linked polyethylene foam). Its shape is adapted to the contour of the inner sheet metal of the car door.

[0048] The doped conductive coating layer 102 is the core layer for achieving electromagnetic shielding in this embodiment. This coating is uniformly applied to the entire outer surface of the film body 101 (i.e., the side facing away from the car door sheet metal) using an electrostatic spraying process. The conductive coating is preferably a nickel-based conductive coating or a copper-based conductive coating that has undergone anti-oxidation treatment. Its surface resistivity after coating and curing is tested to be ≤0.3Ω / 10cm, ensuring the formation of a continuous and efficient conductive path.

[0049] A reinforcing structure 103 is disposed on the membrane body 101 at the wire harness through-hole reserved for the wire harness. This structure includes a reinforcing plastic flange seat 103a and a reinforcing plastic cover plate 103b. Preferably, both are made of the same material as the membrane body 101 (e.g., both are PE) to ensure welding compatibility. The reinforcing plastic flange seat 103a and the reinforcing plastic cover plate 103b cover and clamp the wire harness through-hole 103c from both sides of the membrane body 101, and are welded together as a whole using ultrasonic welding. This "sandwich" structure greatly enhances the tear resistance and fatigue resistance of the through-hole area. The central through-hole of the reinforcing plastic flange seat 103a is precisely designed to form an interference fit with the standard wire harness rubber plug 106 to achieve a dynamic seal.

[0050] A waterproof, breathable, and ventilated unit 104 is disposed on the membrane body 101 in an area away from the wiring harness through-hole 103c (typically located on the upper part of the vehicle door). This unit includes a moisture-wicking and ventilating hole 104c formed in the membrane body 101, and an ePTFE (expanded polytetrafluoroethylene) waterproof and breathable membrane patch 104b bonded to the hole by a water-resistant pressure-sensitive adhesive ring 104a. This ePTFE membrane allows water vapor molecules to pass through but effectively blocks liquid water and dust, thereby achieving pressure balance and humidity regulation between the electrical side space and the external atmosphere.

[0051] A butyl adhesive layer 105 is applied to the inner surface of the film body 101 that is not coated with the conductive coating layer 102, i.e., the side facing the door sheet metal. Butyl adhesive provides excellent long-term adhesion, sealing, and shock absorption. During storage and transportation, this adhesive layer 105 is covered by a release liner.

[0052] In this embodiment, the water-retaining membrane 100 forms a nearly closed electromagnetic shielding cavity through effective electrical contact between the conductive coating layer 102 and the metal sheet metal of the car door, providing protection for the internal precision electrical components.

[0053] Embodiment 2 of the present invention includes: a method for preparing a water-retaining membrane with anti-electromagnetic interference function:

[0054] This embodiment provides a method for preparing the water-retaining membrane 100 as described in Embodiment 1. The method has clear steps and is suitable for automated continuous production. Specifically, it includes the following steps:

[0055] S1: Prepare PE film rolls, nickel-based conductive coating, injection-molded PE material reinforced plastic flange seat ring 103a and reinforced plastic cover plate 103b, ePTFE waterproof and breathable membrane patch 104b, water-resistant pressure-sensitive rubber ring 104a, and butyl adhesive.

[0056] S2: Unwind the PE film and uniformly spray a nickel-based conductive coating onto one surface using an electrostatic spraying device. Control the spraying pressure at 0.4-0.55 MPa and the spraying distance at 15-25 cm. After spraying, allow it to level at room temperature for more than 10 minutes, then place it in a 60℃ drying tunnel for 30 minutes to cure the coating into a conductive coating layer 102. After verifying that its surface resistivity is within acceptable limits, rewind the film for later use.

[0057] S3: Unwind the film roll with conductive coating layer 102, cut it into a blank of a predetermined shape by a precision die-cutting machine, and then use a vacuum forming process to form a three-dimensional shape that matches the curved surface of the car door sheet metal, thus obtaining the preliminary film body 101.

[0058] S4: On the formed film body 101, a wire harness through hole 103c and at least one moisture venting and ventilation hole 140c are precisely die-cut using a mold.

[0059] S5: Place the reinforcing plastic flange seat 103a and the reinforcing plastic cover plate 103b on the wire harness through holes 103c on both sides of the film body 101, and weld them around the through holes using an ultrasonic welding machine. The ultrasonic energy melts the plastic on the contact surface instantly, and after cooling, the three are firmly fused together to form the reinforcing structure 103.

[0060] S6: Remove the release paper from the back of the ePTFE waterproof and breathable membrane patch 104b, and accurately align and press it onto the moisture-venting and breathable holes 104c of the membrane body 101 through the pre-coated water-resistant pressure-sensitive adhesive ring 104a to ensure complete coverage and sealing, forming a waterproof, moisture-permeable and breathable unit 104.

[0061] S7: On the inner surface of the film body 101 (i.e., the side without the conductive layer), butyl adhesive is uniformly applied along its edge area using an automatic adhesive applicator to form a butyl adhesive layer 105. Subsequently, release paper is immediately applied to protect the adhesive surface.

[0062] S8: Perform full-size inspection, conductivity test of the conductive layer, and airtightness test of the breathable unit on the finished water-resistant membrane 100. Qualified products are protected and packaged in special packaging boxes and put into storage for shipment.

[0063] This provides an advanced process route that is efficient, stable, and suitable for large-scale automated production. First, an electrostatic spraying process is used to prepare the conductive layer, ensuring that the surface resistivity of the conductive coating on each product consistently meets the technical requirement of ≤0.3Ω / 10cm, thus guaranteeing a high degree of consistency in electromagnetic shielding effectiveness. Second, ultrasonic welding is used to fix the reinforcing structure. This is a fast, precise, and clean joining technology that requires no auxiliary adhesives. Its energy is concentrated at the welding interface, minimizing the thermal impact on the film body. It enables millisecond-level high-speed welding, making it particularly suitable for assembly line operations and ensuring the long-term reliability of the reinforced area connection. The entire production line, from unwinding, spraying, forming to welding and gluing, is easily automated continuously, greatly improving production efficiency and ensuring the uniformity and stability of product quality. This provides a reliable manufacturing solution to meet the large-scale, high-standard quality requirements of the automotive industry.

[0064] Embodiment 3 of the present invention includes: a method for preparing a water-retaining membrane with anti-electromagnetic interference function:

[0065] This embodiment optimizes the process flow for small- to medium-batch production or specific material compatibility requirements. It employs manual spraying to form the conductive layer and uses hot-press welding to fix the reinforcing structure. The specific steps are as follows:

[0066] S1: Prepare XPE film rolls, copper-based conductive coatings treated with anti-oxidation, injection-molded EVA reinforced plastic flange seats and reinforced plastic covers, ePTFE waterproof and breathable membrane patches, water-resistant pressure-sensitive rubber rings, and butyl adhesive.

[0067] S2: Unwind the XPE film and fix it onto the spraying fixture. According to the manual spraying process parameters in the document, first dilute the copper-based conductive coating at a dilution rate of 30-50% and adjust its application viscosity to 12-15c. Then, using a standard spray gun, maintain a spraying pressure of 0.4-0.55MPa and a spraying distance of 15-25cm to uniformly spray the film surface. After spraying, allow sufficient leveling time (>10 minutes), then place it in an oven at (60±2)℃ for 30 minutes to cure the coating into a conductive coating layer that meets the requirements (surface resistivity ≤0.3Ω / 10cm). This method requires low equipment investment and has relatively relaxed requirements for the operating environment, making it particularly suitable for product development or small-batch production.

[0068] S3: This step is the same as S3 in Example 2. The film with the conductive coating layer is unwound, die-cut, and vacuum-formed to obtain the film body.

[0069] S4: This step is the same as S4 in Example 2. The wire harness through hole 103c and the moisture venting and ventilation hole 104c are die-cut into the formed film body.

[0070] S5: Align the reinforcing plastic flange seat and the reinforcing plastic cover with the wire harness through-hole 103c of the film body and place them in the mold of the hot press welding machine. By controlling the temperature, pressure, and time of the hot press plate, the EVA material reinforcement and the XPE film body are thermally fused and fused at the contact interface. The hot press welding process is particularly suitable for thermoplastic materials such as EVA and XPE, and can form a wide welding surface with high connection strength and good sealing performance.

[0071] S6: This step is the same as S6 in Example 2, where the ePTFE waterproof and breathable membrane patch is bonded to the moisture-wicking and breathable hole 104c by a pressure-sensitive adhesive ring.

[0072] S7: This step is the same as S7 in Example 2, where a butyl adhesive layer is coated on the inner surface of the film body and a release liner is covered.

[0073] S8: This step is the same as S8 in Example 2, which involves inspecting and packaging the finished product.

[0074] By combining manual spraying and hot-press welding processes, the production threshold and equipment costs are reduced. Meanwhile, material optimization (such as the combination of XPE and EVA) ensures the reliability of the final product's performance. This demonstrates the high flexibility and adaptability of the manufacturing method of this invention, allowing for optimization and adjustment according to different production conditions and cost control requirements, further highlighting its broad industrialization prospects.

[0075] Embodiment 4 of the present invention includes: a smart car door system with a water-retaining membrane having anti-electromagnetic interference function.

[0076] This embodiment provides an intelligent car door system, which uses the water-blocking membrane 100 with anti-electromagnetic interference function described in Embodiment 1.

[0077] The system includes a metal door sheet 200, a door opening actuator fixedly installed inside the door sheet 200, an electric suction door lock, radar, ECU and other key electrical components, as well as wiring harnesses connecting these components.

[0078] Its assembly relationship and working principle are as follows:

[0079] During the final assembly of the vehicle door, the electrical components are first installed and the wiring harness is connected. Then, the release liner on the butyl adhesive layer 105 of the water-retaining membrane 100 is removed, and the water-retaining membrane 100 is smoothly and tightly adhered to the door sheet metal 200. At this point, the doped conductive coating layer 102 on the water-retaining membrane 100 achieves large-area, low-impedance electrical contact with the metal door sheet metal 200, and the two together form an electromagnetic shielding cavity 300 that surrounds all electrical components. This cavity can effectively attenuate electromagnetic interference from internal and external vehicle components (such as motors and vehicle communication equipment), ensuring the integrity of the intelligent door control signals.

[0080] The wire harness, through its end rubber, allows the plug 106 to pass tightly (interference fit) through the central through-hole of the reinforcing structure 103 on the water-resistant membrane 100, achieving a dynamic waterproof seal at the wire harness entry point. Simultaneously, the waterproof, breathable, and ventilated unit 104 ensures pressure balance and moisture exchange between the inside of the shielded cavity and the external atmosphere, preventing internal condensation.

[0081] In summary, the water-retaining membrane and its door system of the present invention, through an innovative multi-layer composite structure, comprehensively solves the three major technical challenges faced by intelligent car doors: electromagnetic interference, rainwater leakage, and internal condensation, significantly improving the system's reliability, safety, and service life.

[0082] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A water-retaining membrane with anti-electromagnetic interference function, characterized in that, include: The main body of the film is made of polymer film material; A doped conductive coating layer is applied to the surface of the thin film substrate; At least one reinforcing structure is disposed at the wire harness through-hole of the film body; the reinforcing structure includes a reinforcing plastic flange seat and a reinforcing plastic cover plate, the reinforcing plastic flange seat and the reinforcing plastic cover plate respectively cover the wire harness through-hole from both sides of the film body, and are welded and fixed to the film body as one piece by welding. At least one waterproof, breathable and ventilated unit is disposed on the membrane body; the waterproof, breathable and ventilated unit includes a moisture-venting and venting hole opened on the membrane body, and an ePTFE waterproof and ventilated membrane patch covering and sealing the moisture-venting and venting hole; An adhesive layer is coated on the other surface of the thin film body that is not coated with the doped conductive coating layer.

2. The water-retaining membrane with anti-electromagnetic interference function according to claim 1, characterized in that, The doped conductive coating layer is one of carbon-based conductive coatings, graphite conductive coatings, metal-based conductive coatings, nanotube conductive coatings, or metal oxide conductive coatings.

3. The water-retaining membrane with anti-electromagnetic interference function according to claim 2, characterized in that, The metallic conductive coating is a nickel-based conductive coating or a copper-based conductive coating that has undergone anti-oxidation treatment.

4. The water-retaining membrane with anti-electromagnetic interference function according to claim 1, characterized in that, The surface resistivity of the doped conductive coating layer is ≤0.3Ω / 10cm.

5. The water-retaining membrane with anti-electromagnetic interference function according to claim 1, characterized in that, The polymer film material is one of PE, EVA or XPE.

6. The water-retaining membrane with anti-electromagnetic interference function according to claim 1, characterized in that, The welding method is ultrasonic welding or hot-press welding.

7. The water-retaining membrane with anti-electromagnetic interference function according to claim 1, characterized in that, The ePTFE waterproof and breathable membrane patch is bonded to the moisture-wicking and breathable pores by a pressure-sensitive adhesive ring.

8. A method for preparing a water-retaining membrane with anti-electromagnetic interference function as described in any one of claims 1 to 7, characterized in that, Includes the following steps: S1: Prepare thin film raw materials, doped conductive coating, reinforced plastic flange seat ring, reinforced plastic cover plate, ePTFE waterproof and breathable membrane patch, pressure-sensitive rubber ring and adhesive; S2: Unwind the film, electrostatically or manually spray the doped conductive coating onto one surface, and after leveling and low-temperature drying and curing, form a conductive coating layer, then rewind for later use. S3: Unwind the film with the conductive coating layer, die-cut it, and then perform vacuum forming; S4: Die-cut wire harness through holes and moisture venting holes on the formed film body; S5: Align the reinforcing plastic flange seat and the reinforcing plastic cover plate with the wire harness through-hole of the film body and fix them by welding. S6: The ePTFE waterproof and breathable membrane patch is bonded to the moisture-wicking and breathable holes using a pressure-sensitive rubber ring; S7: Apply an adhesive layer to the surface of the film body that is not coated with a conductive coating layer, and cover it with release paper; S8: Inspect and package the finished product.

9. An intelligent vehicle door system, comprising a metal door sheet metal, an opening actuator mounted thereon, an electric suction door lock, a radar, an ECU, and connecting wiring harnesses, characterized in that, The system is equipped with a water-blocking membrane with anti-electromagnetic interference function as described in any one of claims 1 to 7. The water-blocking membrane is sealed and attached to the door sheet metal through its adhesive layer. The doped conductive coating layer is in electrical contact with the door sheet metal, together forming an electromagnetic shielding cavity. The door opening actuator, electric suction door lock, radar, and ECU are located in the shielding cavity.

10. The intelligent vehicle door system according to claim 9, characterized in that, The connecting wire harness passes through the reinforcing structure in a sealed manner via a wire harness rubber plug.

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