Method for repairing large-size electromagnetic shielding composite rubber sealing element

Abstract

The invention relates to a sealing element repairing technology, and discloses a large-size electromagnetic shielding composite rubber sealing element repairing method which comprises the following steps: determining a damaged position of conductive cloth and determining a repairing area; grinding, coarsening, cleaning and drying the conductive cloth in the repairing area; cutting the lap joint conductive cloth, and grinding, coarsening, cleaning and drying the to-be-bonded surface of the lap joint conductive cloth; a tackifying treatment agent is sprayed on the surfaces of the two parts, and dealcoholized single-component room temperature vulcanized silicone rubber is coated on the surfaces of the two parts; laminating and lapping, and cutting off redundant lapping conductive cloth; covering the plastic cloth, placing the sealing element into a repairing device, and locking and shaping by a fastener; removing the clear glue, replacing the plastic cloth, and locking and curing again; and after curing, the repairing device is dismounted, and room-temperature curing is continued. Through the method, on-site repair of the damaged part of the conductive cloth can be realized, and the bonding stability and the conductive continuity can be maintained.

Description

Technical Field

[0001] This invention belongs to the field of electromagnetic shielding composite material technology, specifically relating to a repair method for large-size electromagnetic shielding composite rubber seals. Background Technology

[0002] Large-size electromagnetic shielding composite rubber seals are important rubber sealing products for achieving sealing and electromagnetic shielding functions in large equipment bodies. They are usually made of rubber materials combined with wear-resistant fabrics, reinforcing fabrics, and conductive fabrics, and formed into stable and reliable composite rubber seals through chemical cross-linking. They are used at the joints of large equipment body structures to achieve functions such as waterproof sealing, load transfer, and electromagnetic shielding.

[0003] During installation and maintenance, these seals are typically fixed to the mounting surface using pressure plates. Waterproof sealant is applied to the outer edge without compromising electromagnetic shielding to ensure a tight seal between the base and the machine body. Due to the large size of the sealing opening (ranging from tens to hundreds of meters in circumference) and the involvement of processes such as fitting holes to the machine body and applying sealant to the bottom, coupled with the need for specific temperature and humidity conditions for sealant application and curing, a significant amount of on-site resources and manpower are required. The installation and maintenance of a single product is time-consuming. When used in large outdoor equipment, these seals may experience normal wear, scratches from foreign objects, or even breakage. Considering the high cost and difficulty of replacement, the need for feasible on-site repairs is particularly prominent.

[0004] Regarding electromagnetic shielding seals with conductive cloth covering the surface, existing technologies include bonding a similar conductive cloth with adhesive backing to the outer surface of the conductive cloth; the corresponding seal structure is usually "double-lip" type, with the main material being silicone rubber and the interior being composite with multiple layers of reinforcing fabric, wherein the lip surface that plays a sealing role is covered with wear-resistant fabric, and the lip surface that plays an electromagnetic shielding role is covered with conductive fabric.

[0005] However, conductive fabrics are typically knitted from polyester yarns plated with silver or copper. Their high metal coverage and relatively inert surface result in insufficient adhesion to other materials. Adhesive-backed conductive fabrics also exhibit limited bonding strength and peel resistance, making them more suitable for planar, non-dynamic applications with less stringent requirements. For large-scale electromagnetic shielding composite rubber seals, whose cross-sections are often non-planar and subjected to repeated compression deformation and shear wear during operation, the aforementioned adhesive-backed conductive fabric bonding method is prone to adhesion failure during use, making it difficult to reliably achieve both critical waterproof sealing and electromagnetic shielding functions.

[0006] Therefore, there is an urgent need for a repair process suitable for large-scale electromagnetic shielding composite rubber seals that can reliably repair damaged areas of the conductive cloth under field conditions and maintain the watertightness and electromagnetic shielding functions that the seals should possess after repair. Summary of the Invention

[0007] This invention provides a repair method for large-size electromagnetic shielding composite rubber seals, which solves the problems of insufficient adhesion between the overlapped conductive cloth and the seal and difficulty in maintaining the shielding function in the prior art.

[0008] To achieve the above objectives, the technical solution proposed by this invention is as follows: Repair method for large-size electromagnetic shielding composite rubber seals includes the following steps: Determine the location of damage to the conductive cloth of the seal, and determine the repair area centered on the location of the damage; The conductive cloth in the repair area is ground to create a rough texture on the surface of the conductive cloth, and the ground conductive cloth is then cleaned and dried. Cut the overlap conductive cloth, grind the surface of the overlap conductive cloth to be bonded to form a rough texture, and clean and dry the ground overlap conductive cloth. An tackifier is sprayed onto the surface of the conductive cloth in the repair area, and a de-alcoholized one-component room temperature vulcanizing silicone rubber is coated onto the surface of the conductive cloth after the tackifier is sprayed; an tackifier is sprayed onto the bonding surface of the overlapping conductive cloth, and a de-alcoholized one-component room temperature vulcanizing silicone rubber is coated onto the surface of the overlapping conductive cloth after the tackifier is sprayed. The overlapping conductive cloth is attached to the conductive cloth in the repair area and the excess overlapping conductive cloth is cut off. A plastic sheet is placed over the surface of the overlapping area, and the sealant and the plastic sheet are placed together in the repair device and locked with fasteners to shape the overlapping area. Remove the repair device and remove the plastic sheet, and remove the alcohol-free one-component room temperature vulcanizing silicone rubber extruded from both sides of the bonding overlap area; Replace the plastic sheet with a clean one and cover the outer layer of the overlapping area. Then, place the sealant and the plastic sheet into the repair device again and lock them in place for curing. After curing is complete, remove the repair device and continue curing at room temperature for the predetermined time. Furthermore, when the damaged location of the seal can be removed from the machine body, the repair device includes an upper mold, a first middle mold, a second middle mold, and a lower mold; The upper mold and the lower mold are disposed opposite to each other, and the first middle mold and the second middle mold are sandwiched between the upper mold and the lower mold; The upper mold, the first middle mold, the second middle mold, and the lower mold, when assembled and locked, together enclose a shaping space for accommodating the sealing element, the plastic sheet, and the overlapping area. The shaping space is used to apply a pressing force to the overlapping area during the shaping and curing process. The repair device is provided with a plurality of threaded holes; the fastener includes a screw, which is threadedly engaged with the threaded holes to detachably lock the upper mold, the first middle mold, the second middle mold and the lower mold.

[0009] Furthermore, when the damaged part of the seal cannot be removed from the machine body, the repair device includes a left mold, a middle mold and a right mold arranged sequentially in the left-right direction; The middle mold is configured to be able to be inserted into the gap formed by the lip portion of the seal, the left mold is in contact with the inner structure of the lip portion, and the right mold is in contact with the outer structure of the lip portion. When assembled and locked, the left mold, the middle mold, and the right mold together form a shaping space for applying a pressing force to the overlapping area; The repair device is provided with a plurality of threaded holes, and the fastener includes a screw rod, which is threadedly engaged with the threaded holes to detachably connect the left mold, the middle mold and the right mold; The repair device has several lifting threaded holes on one side, and lifting components are connected to the external lifting threaded holes.

[0010] Furthermore, the repair area is centered on the damaged location, with 25 to 35 mm on each side of the center line, making the total width of the repair area 50 to 70 mm.

[0011] Furthermore, the grinding process of the conductive cloth includes using a handheld electric drill equipped with abrasive rods to grind the entire repair area from top to bottom twice. The first pass is used to remove the coating on the surface of the conductive cloth, and the second pass is used to form the roughened texture on the surface of the conductive cloth. After grinding, the cloth is wiped with alcohol and allowed to air dry naturally.

[0012] Furthermore, the overlapping conductive cloth is a conductive cloth that has undergone adhesive treatment, and the width of the overlapping conductive cloth is 50 to 70 mm and the length is 120 mm.

[0013] Furthermore, the coating thickness of the dealcohol-type single-component room temperature vulcanizing silicone rubber on the conductive cloth surface and the overlapping conductive cloth surface in the repair area is approximately 0.2 mm.

[0014] Furthermore, the width of the plastic sheet is 70 to 90 mm, and the plastic sheet is used to cover the overlapping area during the shaping and curing stages.

[0015] Furthermore, the curing process includes: curing for 2 to 3 hours while the repair device is locked; and continuing to cure at room temperature for more than 24 hours after the repair device is removed. Furthermore, if the damaged part of the seal cannot be removed from the machine body, before the shaping, after covering it with plastic cloth, use a putty knife to apply slight force from the bottom to the lip to make the conductive cloth and the overlapping conductive cloth fit tightly together, and shape for 1 minute after the repair device is locked.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention employs a grinding process to create a roughened texture on the surfaces of the conductive cloth and overlapping conductive cloth within the repair area. This, combined with an tackifier and the coating and bonding of a de-alcoholized, single-component room-temperature vulcanizing silicone rubber, results in a more stable bonding layer at the interface. This enhances the interface's peel resistance and service reliability. Verification has shown that the bond strength between the conductive cloth and the de-alcoholized, single-component room-temperature vulcanizing silicone rubber reaches 1.4 kN / m, meeting common requirements exceeding 0.5 kN / m. Furthermore, this invention utilizes a repair device to provide clamping force and create a shaping space during the shaping and curing process. This, along with the steps of covering with plastic sheeting, locking and shaping, removing the adhesive, replacing the plastic sheeting, and then locking and curing again, facilitates control over the adhesive layer thickness and the regularity of the overlapping boundaries. This reduces the risk of localized lifting, air trapping, and adhesive overflow affecting assembly after curing, resulting in a repair structure with a smooth appearance and uniform adhesive layer. Furthermore, this invention provides suitable repair device structures and process steps for two types of on-site conditions: those where the damage location can be detached from the main body and those where it cannot. This allows repairs to be carried out on-site, reducing material input and downtime associated with complete replacement. Moreover, the repaired component maintains conductive continuity and electromagnetic shielding functionality. Surface resistance measurements show that the surface resistance of the repaired area is less than 0.5Ω; shielding effectiveness tests show a shielding effectiveness greater than 63dB in the 20MHz to 20GHz frequency band, ensuring that the repaired seal continues to meet electromagnetic shielding and sealing application requirements.

[0017] Of course, implementing the various technical solutions of this invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0018] Figure 1 This is a structural diagram of the repair device according to Embodiment 1 of the present invention; Figure 2 yes Figure 1 Top view; Figure 3 This is a structural diagram of the repair device according to Embodiment 2 of the present invention; Figure 4 yes Figure 3 Top view; In the diagram, 1-upper mold, 2-first middle mold, 3-second middle mold, 4-lower mold, 5-left mold, 6-middle mold, 7-right mold, 8-connecting threaded hole, 9-lifting threaded hole. Detailed Implementation

[0019] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods.

[0020] In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid the core parts of this application being overwhelmed by excessive description. For those skilled in the art, it is not necessary to describe these related operations in detail. They can fully understand the related operations based on the description in the specification and general technical knowledge in the field.

[0021] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0022] The following embodiments illustrate the repair method for large-size electromagnetic shielding composite rubber seals of the present invention. It should be understood that the order of steps described in the embodiments can be appropriately adjusted without departing from the limitations of the claims of the present invention; the size range, curing time, etc., can be reasonably set according to the on-site temperature and humidity conditions. The "overlapping conductive cloth" is a conductive cloth that has undergone adhesive enhancement treatment.

[0023] Example 1: In this embodiment, the damaged location of the seal can be detached from the machine body, see [link / reference]. Figure 1 and Figure 2 The repair device in this embodiment includes an upper mold 1, a first middle mold 2, a second middle mold 3, and a lower mold 4. The upper mold 1 and the lower mold 4 are arranged opposite to each other, and the first middle mold 2 and the second middle mold 3 are sandwiched between the upper mold 1 and the lower mold 4. The repair device is provided with a connecting threaded hole 8, and the fastener includes a screw. The screw is threadedly engaged with the connecting threaded hole 8 to achieve detachable locking, thereby applying a pressing force to the bonding overlap area during the shaping and curing process.

[0024] S1: Prepare tooling and seals to be repaired Remove the repair device and clean it thoroughly. Confirm that there are no foreign objects on the mating surfaces between the upper mold 1, the first middle mold 2, the second middle mold 3, and the lower mold 4 to avoid introducing local warping or indentations during subsequent pressing and shaping.

[0025] S2: Determine the repair area Identify the damaged location of the conductive fabric and mark repair areas 25 to 35 mm to the left and right of the damaged location as the center line, making the total width of the repair area 50 to 70 mm. This method facilitates the formation of sufficient overlap boundaries on both sides of the damaged point, thus providing a continuous stress and adhesive foundation for subsequent bonding.

[0026] S3: Surface grinding, cleaning and drying of conductive cloth Within the repair area, a handheld electric drill equipped with an abrasive rod is used to grind the entire surface twice from top to bottom: the first pass removes the coating on the conductive cloth surface, and the second pass creates a roughened texture on the conductive cloth surface. After grinding, the surface is wiped clean with a clean cloth dampened with alcohol and allowed to air dry. The surface morphology created by the roughened texture facilitates the formation of a more stable bonding layer between the tackifier and the dealcoholized single-component room temperature vulcanizing silicone rubber at the interface.

[0027] S4: Cut the overlapped conductive fabric and perform the same surface treatment. Cut a piece of overlapping conductive cloth according to the width of the repair area, with a width of 50 to 70 mm and a length of 120 mm; repeat the S3 grinding process twice on the surface to be bonded to the overlapping conductive cloth to form a rough texture on the surface, and clean and dry it.

[0028] S5: Apply tackifier and coat with de-alcoholized one-component room temperature vulcanizing silicone rubber. First, an tackifier is sprayed onto the roughened conductive cloth surface in the repair area, followed by a uniform application of a 0.2mm thick layer of de-alcoholized one-component room temperature vulcanizing silicone rubber. Similarly, an tackifier is sprayed onto the roughened conductive cloth surfaces to be bonded, followed by a uniform application of a 0.2mm thick layer of de-alcoholized one-component room temperature vulcanizing silicone rubber. This step creates an overlapping interface of "conductive cloth—silicone rubber transition layer—conductive cloth," facilitating the subsequent pressing and shaping to obtain a uniform adhesive layer.

[0029] S6: Fitting and Trimming Two pieces of conductive cloth coated with de-alcoholized one-component room temperature vulcanizing silicone rubber are evenly bonded together starting from the inner lip and extending to the base, with any excess overlapping conductive cloth trimmed off. Maintaining smooth edges of the overlapping conductive cloth during bonding helps reduce the risk of edge lifting under subsequent repeated compression and deformation conditions.

[0030] S7: Cover with plastic sheeting and insert the repair device for shaping. Cover the overlapping area with a 70-90mm wide plastic sheet. Place the sealant and the plastic sheet together into the repair device and tighten with fasteners to shape the overlapping area. The plastic sheet isolates the adhesive layer from the mold contact surface, facilitating removal and cleaning after shaping.

[0031] S8: Remove the repair device, remove the plastic sheeting, and clean up any excess adhesive. Remove the fasteners, open the repair device and remove the plastic sheet. Remove the extruded alcohol-free single-component room temperature vulcanizing silicone rubber from both sides of the bonding overlap area to make the overlap boundary more regular and avoid the formation of local bulges after curing, which would affect the reassembly and bonding.

[0032] S9: Replace with a clean plastic sheet and tighten and solidify again. Replace the plastic sheet with a clean one and attach it to the outer layer of the conductive cloth. Then, place the sealant and the plastic sheet together into the repair device and tighten them for curing. This "shape first, clean then cure" process facilitates control over the appearance of the overlapping area and the boundaries of the adhesive layer.

[0033] S10: Remove the repair device and continue curing at room temperature. Remove the repair device after curing for 2 to 3 hours; place the repaired seal on a flat surface and continue curing at room temperature for more than 24 hours. The curing time can be adjusted according to temperature and humidity conditions.

[0034] Example 2: In this embodiment, the damaged location of the seal could not be removed from the machine body; see [link to relevant documentation]. Figure 3 and Figure 4 The repair device in this embodiment includes a left mold 5, a middle mold 6 and a right mold 7 arranged sequentially in the left-right direction; the middle mold 6 is configured to be inserted into the gap formed by the lip of the sealing element, the left mold 5 is in contact with the inner structure of the lip, and the right mold 7 is in contact with the outer structure of the lip; the repair device is provided with a connecting threaded hole 8, and the fastener includes a screw and is used for locking; one side of the repair device is provided with a lifting threaded hole 9, which can be connected to an external lifting component for easy handling and positioning.

[0035] S1: Prepare the repair equipment and clean up. Remove the repair device and clean it. Check whether the mating surfaces and pressing surfaces of the left mold 5, middle mold 6, and right mold 7 are clean to ensure that a stable shaping space can be formed after assembly and that uniform pressing force is provided to the mating and overlapping areas.

[0036] S2: Determine the repair area Using the damage location as the center line, mark the repair area 25 to 35 mm to the left and right, making the total width of the repair area 50 to 70 mm. This width is designed to easily cover the damage point and create an overlapping transition area on both sides.

[0037] S3: Surface grinding, cleaning and drying of conductive cloth Use a handheld drill with abrasive pads to grind the marked area twice from top to bottom: the first pass removes the surface coating, and the second pass creates a rough texture; then wipe the surface with a cloth dampened with alcohol and let it air dry.

[0038] S4: Cut and process the overlapping conductive fabric. Cut a piece of conductive fabric with a width of 50 to 70 mm and a length of 120 mm; repeat the S3 grinding process twice on the surface to be bonded, clean it, and let it dry.

[0039] S5: Apply tackifier and coat with de-alcoholized one-component room temperature vulcanizing silicone rubber. Apply an tackifier to the roughened conductive cloth surface in the repair area and evenly coat it with a 0.2mm thick layer of de-alcoholized one-component room temperature vulcanizing silicone rubber; similarly apply an tackifier to the overlapping conductive cloth surfaces to be bonded and coat them with a 0.2mm thick layer of de-alcoholized one-component room temperature vulcanizing silicone rubber.

[0040] S6: Fitting and Trimming Two pieces of conductive cloth coated with de-alcoholized one-component room temperature vulcanizing silicone rubber are evenly overlapped from the inside of the inner lip, extending to the bottom edge of the installation, and the excess overlapped conductive cloth is cut off.

[0041] S7: Cover with plastic sheeting and perform manual pre-pressing. Cover the overlapping area with a piece of plastic sheeting 70 to 90 mm wide. Before assembling the repair device, apply slight pressure from the bottom to the lip with a putty knife to ensure the conductive cloth adheres tightly to the overlapping conductive cloth. This pre-compression process helps to eliminate local warping or air trapping in space-constrained environments, creating conditions for subsequent assembly, pressing, and shaping.

[0042] S8: Assemble the repair device and lock it in place. Insert the middle mold 6 into the gap formed by the lip of the sealing component, so that the left mold 5 is close to the inner structure and the right mold 7 is close to the outer structure; lock the left mold 5, middle mold 6 and right mold 7 by fastening the fastener (screw) with the threaded connection hole 8, and shape the overlapping area for 1 minute.

[0043] S9: Remove the repair device and clean up any excess adhesive. Remove the repair device and plastic sheeting, and clean the extruded de-alcoholized single-component room temperature vulcanized silicone rubber on both sides of the overlapping area to ensure a smooth overlap boundary.

[0044] S10: Replace with a clean plastic sheet and tighten to cure. Replace the outer layer of the overlapping area with a clean plastic sheet with a width of 70 to 90 mm, reassemble the repair device, and tighten it with fasteners to cure.

[0045] S11: Remove the repair device and continue curing at room temperature. Remove the repair device after 2 to 3 hours of curing. The repaired seal should continue to cure at room temperature for more than 24 hours. The curing time can be adjusted according to temperature and humidity conditions.

[0046] After completing the repair process described in Example 1 or Example 2, and curing for 2 to 3 hours with the repair device locked, and then continuing to cure at room temperature for more than 24 hours after removing the repair device, the repaired area is inspected for appearance and electrical properties, and the repair effect is verified by combining adhesive strength and shielding effectiveness tests.

[0047] First, from the perspective of appearance and structural integrity, a compression test was performed on the conductive cloth overlap interface of the repaired area: holding the repaired area 300 to 400 mm away from both sides, gently applying horizontal pressure downwards, compressing the sealing component to 25 to 30 mm, no delamination was observed on both sides of the conductive cloth on the inner lip of the repaired area. This inspection demonstrates that the repaired overlap interface can still maintain a stable fit under pressure deformation, meeting the basic requirement of repeated compression deformation of the seal under actual working conditions.

[0048] Secondly, from the perspective of electrical continuity, surface resistance was tested at the repaired area: test electrodes were placed 5 to 10 mm from both ends of the repaired conductive fabric to measure the surface resistance. The test results showed that the surface resistance of the repaired area was less than 0.5 Ω. This result indicates that a continuous conductive path can be formed between the repaired and original conductive fabric, which is beneficial for maintaining the conductive continuity required for electromagnetic shielding.

[0049] Furthermore, the interfacial adhesion performance between the conductive cloth, the dealcoholized one-component room temperature vulcanizing silicone rubber, and the conductive cloth was verified. Standard samples were prepared according to GB / T 532-2008, and the adhesion performance between the three components was tested using a simulated actual repair process. The obtained adhesion strength reached 1.4 kN / m (1.4 kN / m), far exceeding the industry requirement of 0.5 kN / m (0.5 kN / m). This experimental result demonstrates that the combined process of "surface roughening, tackifying agent, room temperature vulcanizing silicone rubber layer, and pressing and curing with a repair device" can significantly improve the interfacial peel resistance between conductive cloths, thus better meeting the service requirements of seals under complex conditions such as repeated extrusion deformation and shear wear.

[0050] Furthermore, regarding the electromagnetic shielding function, the shielding effectiveness of the scaled-down component was tested in the 20MHz to 20GHz frequency band according to the GJB 8820 test method. The test results showed that the shielding effectiveness was greater than 63dB. The electromagnetic shielding effectiveness test report after repair is attached as Appendix 1. This conclusion indicates that the repair process can not only restore the mechanical integrity and conductive continuity of the overlapping area, but also maintain a high level of shielding effectiveness within the stated frequency band, meeting the functional consistency requirements of electromagnetic shielding seals.

[0051] Based on the above inspection and test results, it can be concluded that the repair method of the present invention is applicable to both scenarios where the damaged area can be detached from the body and scenarios where the damaged area cannot be detached from the body. By providing a stable clamping force through the repair device to ensure that the adhesive layer is uniform and fully adhered to the interface, high bonding strength and low surface resistance can be obtained, and good shielding effectiveness can be maintained within the test frequency band, thereby achieving reliable repair and continuous use of large-size electromagnetic shielding composite rubber seals.

[0052] Without departing from the scope of the claims of this invention, the repair method and repair device of this invention can also be extended to the following applications: First, the repair device can be customized according to the cross-sectional shape of the product to be repaired, making it suitable for repairing other types of products with conductive fabrics bonded to the surface, so as to meet the pressing and shaping requirements of different cross-sectional structures; Second, the width of the overlapping conductive cloth can be adjusted according to the length of the damaged or broken area of ​​the part to be repaired, or the repair device can be appropriately lengthened to expand the repair scenarios that can be covered, especially for large-area damage, which is conducive to reducing the number of segmented repairs and shortening the on-site operation time; Third, while keeping the grinding and roughening, adhesion enhancement and pressing and shaping process unchanged, by changing the adhesive used, this invention can be applied to the repair of non-electromagnetic shielded rubber seal products with surface composite polytetrafluoroethylene film, polyester fabric or nylon fabric and other materials, thereby expanding the application scope of this invention on seals of different surface composite materials.

[0053] For those skilled in the art, various improvements and modifications can be made without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention.

Claims

1. A method for repairing large-size electromagnetic shielding composite rubber seals, characterized in that, Includes the following steps: Determine the location of damage to the conductive cloth of the seal, and determine the repair area centered on the location of the damage; The conductive cloth in the repair area is ground to create a rough texture on the surface of the conductive cloth, and the ground conductive cloth is then cleaned and dried. Cut the overlap conductive cloth, grind the surface of the overlap conductive cloth to be bonded to form a rough texture, and clean and dry the ground overlap conductive cloth. An tackifier is sprayed onto the surface of the conductive cloth in the repair area, and a de-alcoholized one-component room temperature vulcanizing silicone rubber is coated onto the surface of the conductive cloth after the tackifier is sprayed; an tackifier is sprayed onto the bonding surface of the overlapping conductive cloth, and a de-alcoholized one-component room temperature vulcanizing silicone rubber is coated onto the surface of the overlapping conductive cloth after the tackifier is sprayed. The overlapping conductive cloth is attached to the conductive cloth in the repair area and the excess overlapping conductive cloth is cut off. A plastic sheet is covered on the surface of the overlapping area. The sealant and the plastic sheet are placed together in the repair device and locked with fasteners to shape the overlapping area. Remove the repair device and remove the plastic sheet, and remove the alcohol-free one-component room temperature vulcanizing silicone rubber extruded from both sides of the bonding overlap area; Replace the plastic sheet with a clean one and cover the outer layer of the overlapping area. Then, place the sealant and the plastic sheet into the repair device again and lock them in place for curing. After curing is complete, remove the repair device and continue curing at room temperature for the predetermined time.

2. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, When the damaged location of the seal can be removed from the machine body, the repair device includes an upper mold, a first middle mold, a second middle mold, and a lower mold; The upper mold and the lower mold are disposed opposite to each other, and the first middle mold and the second middle mold are sandwiched between the upper mold and the lower mold; The upper mold, the first middle mold, the second middle mold, and the lower mold, when assembled and locked, together enclose a shaping space for accommodating the sealing element, the plastic sheet, and the overlapping area. The shaping space is used to apply a pressing force to the overlapping area during the shaping and curing process. The repair device is provided with a plurality of threaded holes; the fastener includes a screw, which is threadedly engaged with the threaded holes to detachably lock the upper mold, the first middle mold, the second middle mold and the lower mold.

3. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, When the damaged part of the seal cannot be removed from the machine body, the repair device includes a left mold, a middle mold and a right mold arranged sequentially in the left-right direction; The middle mold is configured to be able to be inserted into the gap formed by the lip portion of the seal, the left mold is in contact with the inner structure of the lip portion, and the right mold is in contact with the outer structure of the lip portion. When assembled and locked, the left mold, the middle mold, and the right mold together form a shaping space for applying a pressing force to the overlapping area; The repair device is provided with a plurality of threaded holes, and the fastener includes a screw rod, which is threadedly engaged with the threaded holes to detachably connect the left mold, the middle mold and the right mold; The repair device has several lifting threaded holes on one side, and lifting components are connected to the external lifting threaded holes.

4. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, The repair area is centered on the damaged location, with 25 to 35 mm on each side of the center line, making the total width of the repair area 50 to 70 mm.

5. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, The grinding process of the conductive cloth includes using a hand-held electric drill equipped with abrasive rods to grind the entire repair area from top to bottom twice. The first pass is used to remove the coating on the surface of the conductive cloth, and the second pass is used to form the roughened texture on the surface of the conductive cloth. After grinding, wipe with a cloth soaked in alcohol and let it air dry naturally.

6. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, The overlapping conductive cloth is a conductive cloth that has undergone adhesive treatment, and the width of the overlapping conductive cloth is 50 to 70 mm and the length is 120 mm.

7. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, The coating thickness of the dealcohol-type single-component room temperature vulcanizing silicone rubber on the conductive cloth surface and the overlapping conductive cloth surface in the repair area is approximately 0.2 mm.

8. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, The width of the plastic sheet is 70 to 90 mm, and the plastic sheet is used to cover the overlapping area during the shaping and curing stages.

9. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 1, characterized in that, The curing process includes: curing for 2 to 3 hours while the repair device is locked; and continuing to cure at room temperature for more than 24 hours after the repair device is removed.

10. The repair method for large-size electromagnetic shielding composite rubber seals according to claim 3, characterized in that, If the damaged part of the seal cannot be removed from the machine body, before the shaping, cover it with plastic cloth and use a putty knife to apply slight force from the bottom to the lip to make the conductive cloth and the overlapping conductive cloth fit tightly together, and shape for 1 minute after the repair device is locked.

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