Parallel single ground wire metal shielding tape cable and preparation method thereof

Abstract

The invention provides a parallel single ground wire metal shielding tape cable and a preparation method thereof.The preparation method comprises the steps that the surface of a conductor is coated with a modified insulating layer, the modified insulating layer is heated to 150-200 DEG C and subjected to heat vulcanization for 10-30 minutes, a core wire wrapping body is obtained, and the modified insulating layer comprises an insulating matrix and reinforcing filler; respectively coating a corrosion-resistant layer and an adhesive layer on the surfaces of the two sides of the metal shielding tape to obtain a metal shielding wrapping tape, longitudinally wrapping the metal shielding wrapping tape on the surface of the core wire wrapping body, laminating through a rolling mechanism, and thermally curing for 5-10 seconds under the condition of 130-150 DEG C to form a longitudinal shielding cable middle-layer structure; and winding a flexible protective film on the surface of the metal shielding wrapping tape of the middle layer structure of the longitudinal shielding cable, spraying an elastomer coating liquid to form a protective film layer, and drying at 80 DEG C for 2-5 minutes to complete curing, thereby obtaining the parallel single ground wire metal shielding tape cable. An integral packaging structure is formed, the metal shielding tape is restrained from loosening, stress-induced cracking or edge warping debonding is avoided, and the structural integrity of the parallel single-ground-wire metal shielding tape cable under high-frequency dynamic loads is improved.

Description

Technical Field

[0001] This invention belongs to the field of cable material technology, and particularly relates to a parallel single-ground wire metal shielded cable and its preparation method. Background Technology

[0002] High-speed flat parallel cable is a cable structure consisting of multiple conductors arranged in a parallel configuration and encapsulated in an insulating material. It is specifically designed for high-frequency signal transmission, synchronous data communication, and electromagnetic interference control, featuring high speed, low crosstalk, easy layout, and strong shielding. Because the conductors are arranged in parallel and of uniform length, delay matching is excellent, facilitating high-speed digital signal synchronous transmission. The low dielectric constant insulation material reduces signal attenuation and loss, increasing transmission frequency (up to Gbps levels). The use of a metal strip structure creates an impedance-controlled path, suppressing crosstalk and reflections.

[0003] However, most existing high-speed parallel cables are single-ground wire metal-coated structures. During high-frequency transmission, the electromagnetic waves of the signal are concentrated in the microscopic region of the conductor surface due to the skin effect. When the signal frequency exceeds 25 GHz, the skin depth decreases significantly, and the transmission loss becomes highly dependent on the electromagnetic coupling integrity between the conductor and the shielding structure. The metal strips (such as aluminum foil and copper strips) used in existing cables are mostly lapped structures, with tiny air gaps and contact discontinuities at their edges. These irregular gaps introduce micro-reflections, impedance abrupt changes, and leakage magnetic paths, leading to increased insertion loss and deteriorated signal integrity, making it difficult to meet the requirements for transmission stability and low loss in the 25 GHz and above frequency bands. Moreover, existing metal-coated strips are prone to micro-peeling or structural loosening due to thermal expansion and contraction, bending stress, or long-term vibration, especially in high-speed motion or flexible bending environments. This structural looseness disrupts the tight contact between the metal strip and the conductor, weakens the shielding continuity, and may introduce high-frequency anomalies such as unstable grounding, EMI leakage, and common-mode interference coupling. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a parallel single-ground wire metal shielded cable and its preparation method, aiming to solve the problems of loose contact and loose structure of the metal strip in the cable.

[0005] To solve the above-mentioned technical problems, the present invention is implemented as follows: a method for preparing a parallel single-ground wire metal shielded cable is proposed, the steps of which include: S1. A modified insulation layer is coated on the surface of the conductor and heated to 150~200℃ for hot vulcanization for 10~30 minutes to obtain the core wire wrapping, wherein the modified insulation layer includes an insulation matrix and reinforcing filler; S2. Coat the two sides of the metal shielding tape with a corrosion-resistant layer and an adhesive layer respectively to obtain the metal shielding tape. Wrap the metal shielding tape longitudinally on the surface of the core wire covering body and bond it by a rolling mechanism. Heat cure it at 130~150°C for 5~10 seconds to form the middle layer structure of the longitudinal shielded cable. S3. Wrap a flexible protective film around the surface of the metal shielding tape in the middle layer of the longitudinal shielded cable, then spray an elastomer coating liquid to form a protective film layer, and dry it at 80°C for 2-5 minutes to complete the curing, thus obtaining a parallel single-ground wire metal shielded cable.

[0006] In some embodiments, step S1 includes: S1.1 Disperse the filler raw material in an organic solvent, add a modifier, stir at 50~80℃ for 30 minutes, and then dry under normal pressure to obtain the reinforced filler; S1.2. Determine the insulating matrix as component A, and the crosslinking agent and hydrogen-containing silicone oil as component B. Slowly add the reinforcing filler to component A in a dry state for dispersion and mixing. Set the mixing conditions to a dispersion process with a stirring speed of 2000 rpm and a degassing process with a stirring speed of 800 rpm. The mixing time is 5-8 minutes. Then add component B to component A and reinforcing filler and mix them at a weight ratio of 100:100:(3-8). Perform secondary mixing and degassing again for 3-5 minutes to obtain reinforced liquid rubber. S1.3. Apply reinforced liquid rubber to the conductor surface to form a modified insulation layer, heat to 150~200℃ and vulcanize for 10~30 minutes, keeping the heating rate within 3℃ / min to obtain the core wire wrapping.

[0007] In some embodiments, in step S1, the filler raw material includes at least one of nano-alumina particles, nano-silica particles, and nano-zirconia particles; the insulating matrix includes at least one of vinyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, and fluorinated polysiloxane; and the crosslinking agent includes at least one of difluoropropylene-based polyfunctional silane, propyltriethoxysilane isocyanate, propyltrimethoxysilane isocyanate, and ethyl carbamate propyltriethoxysilane.

[0008] In some embodiments, step S2 includes: S2.1 Place the metal shielding tape in a mixture of ethanol and acetone and ultrasonically clean it for 10 minutes. After hot air drying, apply a corrosion-resistant coating sol to one side of the metal shielding tape. After hot pressing, a corrosion-resistant layer is formed. Apply an adhesive to the side of the metal shielding tape away from the corrosion-resistant layer to form an adhesive layer. S2.2 Align the adhesive layer of the metal shielding tape with the core wire wrapping body, and longitudinally bond it along the axial direction of the core wire wrapping body using a rolling mechanism at a constant linear speed of 0.51~1m / min and a contact pressure of 1.5~2kg / cm². S2.3 After bonding, place it in a constant temperature drying oven, set the temperature to 130~150℃, and keep it warm for 5~10 seconds to form the middle layer structure of the longitudinal shielded cable.

[0009] In some embodiments, in step S2, the metal shielding strip includes at least one of aluminum-nickel alloy, tin-plated copper foil, and stainless steel; the corrosion-resistant coating sol includes at least one of titanium dioxide-doped silica sol, zirconium oxide-silica composite sol, fluorosilica hybrid sol, cerium-doped silica sol, and phosphorus-silica hybrid sol; and the adhesive includes at least one of epoxy-modified acrylate adhesive, polyurethane thermosetting adhesive, polyimide structural adhesive, and polyesteramide copolymer.

[0010] In some embodiments, step S3 includes: S3.1 Wrap the flexible protective film around the surface of the metal shielding tape in the middle layer of the longitudinal shielded cable, spray foamed gel evenly on the surface of the flexible protective film, heat to 120~150℃, hold for 5~10 seconds to form a buffer coating. S3.2. Spray the elastomer coating liquid evenly onto the surface of the buffer coating. After spraying, heat to 80℃ and dry for 2-5 minutes to complete the curing, and obtain a parallel single-ground wire metal shielded cable.

[0011] In some embodiments, in step S3, the flexible protective film includes at least one of fluorosilicone elastic film, polyimide polyurethane composite film, and fluorinated polyether film; the foaming gel includes at least one of polyurethane elastic foaming gel, silicone foaming gel, and acrylate foaming gel; and the elastomer coating liquid includes at least one of perfluorinated elastomer coating liquid, silicone polyurethane hybrid elastomer coating liquid, and fluorosilicone elastic coating liquid.

[0012] This invention proposes a parallel single-ground wire metal shielded cable, which is manufactured by the method described above for preparing a parallel single-ground wire metal shielded cable.

[0013] Compared with existing technologies, the parallel single-ground wire metal shielded cable and its manufacturing method disclosed in this invention have the following advantages: By coating the conductor surface with a densely adhered modified insulation layer, mechanical strength and dimensional stability are improved, significantly reducing problems such as enhanced local electric field, reflection loss, and dielectric inhomogeneity caused by poor contact. A double-sided functional coating design, consisting of an adhesive layer and a corrosion-resistant layer, is implemented on the metal shielding tape, achieving longitudinal uniform compaction and gap-free adhesion between the metal shielding tape and the core wire enclosure. Compared to traditional overlapping wrapping structures, this method forms a linear continuous adhesive path, significantly reducing the risk of gaps and peeling along the cable length, thereby improving the shielding closure of the metal tape against high-frequency leakage electric fields and suppressing EMI leakage and insertion loss fluctuations. Finally, a protective film layer is formed by winding a flexible protective film and spraying an elastomer coating liquid, which buffers thermal expansion and contraction, absorbs mechanical shock, and provides dynamic structural stability during long-term use. After thermosetting, the elastomer coating forms an integrated encapsulation structure, further constraining the metal shielding tape from loosening, preventing stress-induced cracking or edge peeling, and improving the structural integrity of the parallel single-ground wire metal shielding tape cable under high-frequency dynamic loads. Attached Figure Description

[0014] Figure 1 This is a schematic cross-sectional view of a parallel single-ground wire metal shielded cable according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a parallel single-ground wire metal shielded cable according to an embodiment of the present invention.

[0015] Label Explanation: 10. Conductor; 20. Modified insulation layer; 30. Metal shielding tape; 40. Flexible protective film; 50. Ground wire. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] Please refer to Figure 1 and Figure 2 This invention proposes a method for preparing a parallel single-ground wire 50mm metal shielded cable, the steps of which include: S1. A modified insulation layer 20 is coated on the surface of conductor 10 and heated to 150~200℃ for hot vulcanization for 10~30 minutes to obtain a core wire wrapping, wherein the modified insulation layer 20 includes an insulation matrix and a reinforcing filler.

[0018] Step S1 includes: S1.1 Disperse the filler raw material in an organic solvent, add a modifier, stir at 50~80℃ for 30 minutes, and then dry under normal pressure to obtain the reinforced filler; the filler raw material includes at least one of nano alumina particles, nano silica particles, and nano zirconium oxide particles.

[0019] In step S1.1, inorganic filler raw materials such as nano-alumina particles, nano-silica particles, or nano-zirconia particles are dispersed in an organic solvent, and a modifier (such as aminopropyltriethoxysilane) is added. Stirring and drying under medium-low temperature conditions and normal pressure significantly improves the surface activity of the filler and its interfacial compatibility with the organosilicon matrix. During this process, the silane functional groups of the modifier can undergo condensation reactions with the hydroxyl groups on the surface of the inorganic particles to generate stable silicon-oxygen bridges. Simultaneously, its organic end groups can participate in the subsequent cross-linking reaction of the rubber system, thereby achieving the construction of a chemically bonded interface between the filler and the matrix. This step ensures that the reinforcing filler is uniformly dispersed in the subsequent silicone rubber, avoids agglomeration, and improves the dispersion stability, interfacial bonding strength, and dielectric stability of the system.

[0020] S1.2. Determine the insulating matrix as component A, and the crosslinking agent and hydrogen-containing silicone oil as component B. Slowly add the reinforcing filler to component A in a dry state for dispersion and mixing. Set the mixing conditions to a dispersion process at a stirring speed of 2000 rpm and a degassing process at a stirring speed of 800 rpm, with a mixing time of 5-8 minutes. Then add component B to component A and the reinforcing filler, and mix them at a weight ratio of 100:100:(3-8). Perform secondary mixing and degassing again for 3-5 minutes to obtain reinforced liquid rubber. The insulating matrix includes at least one of vinyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, and fluorinated polysiloxane. The crosslinking agent includes at least one of difluoropropylene-based polyfunctional silane, propyltriethoxysilane, propyltrimethoxysilane, and ethyl carbamate-propyltriethoxysilane.

[0021] In step S1.2, the insulating matrix component A and the crosslinking agent component B are first determined. After clarifying the system composition, the reinforcing filler is added to component A for high-shear dispersion and vacuum degassing. This significantly improves the uniformity of filler distribution in the main chain and removes air bubbles introduced during the mixing process, reducing dielectric loss. In component A, vinyl-terminated polydimethylsiloxane has good flexibility and extremely low polarity, while fluorinated modified polysiloxane can further enhance corrosion resistance. In component B, hydrogen-containing silicone oil can undergo addition crosslinking with vinyl or hydroxyl functional groups under platinum catalysis, while isocyanate crosslinking agents such as propyltriethoxysilane isocyanate can undergo condensation reactions with hydroxyl-terminated PDMS to form polyurea bonds. The above mixing and secondary degassing processes are carried out within a certain speed and time window, achieving physical coating and chemical embedding of the reinforcing filler and rubber matrix, improving the system's adhesive strength, thermal stability, and dielectric uniformity, which is the foundation for forming a stable insulation layer for high-frequency cables.

[0022] S1.3. The reinforced liquid rubber is coated on the surface of the conductor 10 to form a modified insulation layer 20. The layer is heated to 150~200℃ and kept at the temperature for 10~30 minutes for curing. The heating rate is kept within 3℃ / min to obtain the core wire wrapping.

[0023] In step S1.3, the uniformly dispersed reinforced liquid rubber system is coated onto the surface of conductor 10 and subjected to thermal vulcanization within a set temperature range to form a continuous and dense modified insulation layer 20. In this thermal vulcanization reaction, vinyl groups and hydrogen-containing silicone oil crosslink through an addition mechanism under the action of a platinum catalyst to form a three-dimensional network structure, or isocyanate crosslinking agents and hydroxyl PDMS undergo a condensation reaction to form urea bonds, thereby constructing an elastic coating with high flexibility, thermal stability, and dielectric insulation. Controlling the heating rate within a low range (no more than three degrees Celsius per minute) avoids thermal stress or uneven crosslinking within the rubber compound, ensuring consistent coating interface adhesion and stable thickness, thereby improving the impedance matching and dielectric breakdown resistance of the entire cable during high-frequency signal transmission. The final core wire enclosure possesses good flexibility, heat resistance, and corrosion resistance, forming the basis for reliable bonding of the subsequent shielding structure.

[0024] S2. A corrosion-resistant layer and an adhesive layer are coated on both sides of the metal shielding tape to obtain a metal shielding tape 30. The metal shielding tape 30 is wrapped longitudinally on the surface of the core wire covering body and bonded by a rolling mechanism. It is then heat-cured at 130~150°C for 5~10 seconds to form a longitudinal shielded cable middle layer structure.

[0025] Step S2 includes: S2.1. The metal shielding strip is ultrasonically cleaned in a mixture of ethanol and acetone for 10 minutes, and then dried with hot air. A corrosion-resistant coating sol is applied to one side of the metal shielding strip, and a corrosion-resistant layer is formed after hot pressing. An adhesive is applied to the side of the metal shielding strip away from the corrosion-resistant layer to form an adhesive layer. The metal shielding strip includes at least one of aluminum-nickel alloy, tin-plated copper foil, and stainless steel. The corrosion-resistant coating sol includes at least one of titanium dioxide-doped silica sol, zirconium oxide-silica composite sol, fluorosilica hybrid sol, cerium-doped silica sol, and phosphorus-silica hybrid sol. The adhesive includes at least one of epoxy-modified acrylate adhesive, polyurethane thermosetting adhesive, polyimide structural adhesive, and polyesteramide copolymer.

[0026] In step S2.1, the metal shielding tape is first ultrasonically cleaned with a mixture of ethanol and acetone. This effectively removes surface oil, oxide layers, and residual particles, providing a clean and activated metal surface for subsequent coating and improving the chemical reactivity of the adhesion interface. The selected metal shielding tape materials, such as aluminum-nickel alloy, tin-plated copper foil, and stainless steel, all possess good conductivity and basic corrosion resistance. Among them, aluminum-nickel alloy maintains good structural stability even in strong acid environments. Subsequently, a corrosion-resistant coating material, such as titanium dioxide-doped silica sol, zirconium oxide-silica composite sol, or fluorosilica hybrid sol, is uniformly coated on one side of the metal shielding tape. These coatings form a dense inorganic or hybrid organic-inorganic network structure under heating or hot-pressing conditions, creating a coating with high barrier performance against acidic media, water vapor, or salt spray, significantly enhancing the service life of the metal tape in harsh cable wiring environments. The adhesives applied to the back, such as epoxy-modified acrylate adhesives, polyurethane thermosetting adhesives, or polyesteramide copolymer adhesives, have good flexibility, thermosetting properties, and heat fatigue resistance, which can achieve a firm bond between the metal strip and the core wire wrapping, while taking into account long-term flexibility and structural toughness.

[0027] Preparation method of titanium dioxide-doped silica sol: Tetraethyl orthosilicate (TEOS) and isopropanol were mixed at a volume ratio of 1:4 and magnetically stirred at room temperature until homogeneous. An appropriate amount of deionized water was added (controlling the molar ratio of water to TEOS at 4:1), and a small amount of nitric acid was added dropwise to adjust the pH to 2-3. Stirring was continued for 60 minutes to hydrolyze and form a silica sol system. Then, tetrabutyl titanate (or isopropyl titanate) was slowly added, controlling the molar ratio of titanium to silicon at 1:5, and stirring was continued for another 30 minutes to complete the doping reaction. The system temperature was maintained at 25-30℃ during the reaction, ultimately yielding a transparent and stable titanium dioxide-doped silica sol with excellent corrosion resistance and film density.

[0028] Preparation method of zirconia-silica composite sol: First, add an appropriate amount of zirconium nitrate to ethanol, controlling the molar concentration of tetravalent zirconium ions to 0.2 mol / L, and sonicate for 30 minutes. Separately, dissolve TEOS in anhydrous ethanol at a molar ratio of Zr:Si = 1:3, add a small amount of deionized water and nitric acid (to adjust the pH to 1-2), and pre-hydrolyze for 30 minutes. Then, mix the two solutions and stir at 40℃ for 1 hour to form a homogeneous zirconia-silica composite sol, which has good heat resistance, acid and alkali corrosion resistance, and adhesion.

[0029] Preparation method of fluorosilicone hybrid sol: 3-aminopropyltriethoxysilane (APTES) and trifluoropropyltriethoxysilane (TFPTES) are mixed in a molar ratio of 1:1, diluted with anhydrous ethanol to a concentration of 0.2 mol / L, and the pH is adjusted to 4.5 by adding deionized water and a small amount of acetic acid at room temperature. A hydrolysis-condensation reaction is then carried out for 90 minutes. This yields a fluorosilicone hybrid sol with fluorinated side groups and a silicon-oxygen backbone, exhibiting excellent hydrophobicity, chemical resistance, and electrical insulation, making it suitable for metal protection environments.

[0030] Preparation method of cerium-doped silica sol: Under stirring conditions, cerium nitrate is dissolved in ethanol, controlling the cerium ion concentration to be 0.05 mol / L. This solution is slowly added to a pre-hydrolyzed TEOS system (silanol, ethanol, and water in a ratio of 1:4:4, pH controlled at 3-4), and stirred continuously at 35℃ for 90 minutes to form a uniform and stable cerium-doped silica sol. The cerium ions in this sol can provide cathodic suppression function and improve the self-healing and pitting corrosion resistance of the sol film.

[0031] Preparation method of phosphorus-silicon hybrid sol: Tetraethyl orthosilicate and triethyl phosphate (TEP) are mixed in ethanol at a molar ratio of 3:1 and stirred at room temperature for 30 minutes. An aqueous phase (pH=2) adjusted with hydrogen chloride is slowly added, maintaining a water-silicon molar ratio of 4:5. Stirring continues for 60-90 minutes, allowing the phosphate ester to hydrolyze under acidic conditions and condense with silanols to form a phosphorus-oxysilicon framework, resulting in a highly uniform phosphorus-silicon hybrid sol with strong film-forming properties. This sol can improve the flame retardancy and tracking resistance of shielding tape surfaces.

[0032] Preparation method of epoxy-modified acrylate adhesive: Bisphenol A type epoxy resin (E-51) is heated to 60℃, and glycidyl acrylate (GMA) is added as a graft monomer under stirring at a molar ratio of 1:1. The reaction is catalyzed by triethylamine for 90 minutes to obtain an epoxy acrylate prepolymer with active double bonds. Subsequently, styrene and butyl methacrylate are added as copolymer diluents, and an appropriate amount of benzoyl peroxide is added as an initiator. After uniform dispersion, an epoxy-modified acrylate adhesive with both photocurable and thermocurable properties is obtained, exhibiting excellent metal adhesion and weather resistance.

[0033] Preparation method of polyurethane thermosetting adhesive: Under anhydrous conditions, polyether polyol (molecular weight 1000~2000) and isocyanate (such as HDI or MDI) are added to a reactor at an NCO:OH molar ratio of 1.1:1, and stirred at 80℃ for 2 hours to generate a prepolymer. After cooling to 40℃, a small amount of hydroxyl-terminated acrylic acid is added for end-capping, and a catalyst (such as dibutyltin dilaurate) and a crosslinking agent (such as trimethylolpropane) are added. After adjusting the viscosity, it can be used for thermosetting bonding. The resulting polyurethane adhesive has excellent resistance to humid heat and low-temperature flexibility, and is particularly suitable for bonding flexible metal strips to insulation layers.

[0034] Preparation method of polyimide structural adhesive: Using pyromellitic dianhydride (PMDA) and 4,4′-diaminodiphenyl ether (ODA) as raw materials, a polyamic acid prepolymer is generated by reacting them in NMP solution at a molar ratio of 1:1. The stirring temperature is from room temperature to 50°C, and the reaction time is approximately 4 hours. Subsequently, a thermal imidization reaction is carried out, followed by baking at 250°C for 2 hours to form a polyimide structural adhesive with strong cohesion and high thermal stability. This adhesive is commonly used in high-performance aerospace and heat-resistant electronic component bonding applications.

[0035] Preparation method of polyesteramide copolymer: Adipic acid, terephthalic acid, and hexamethylenediamine are mixed with a diol (such as 1,4-butanediol) in an appropriate ratio under nitrogen protection, and heated to 200℃ for a polycondensation reaction for 4 hours to form a polyesteramide copolymer. Its copolymer system retains the strong hydrogen bonding of the amide bond while possessing the flexibility of the polyester segment, exhibiting excellent adhesion, heat resistance, and flexibility, making it an excellent thermosetting adhesive suitable for high-performance composite laminate structures.

[0036] S2.2 Align the adhesive layer of the metal shielding tape with the core wire wrapping body, and longitudinally bond it along the axial direction of the core wire wrapping body using a rolling mechanism at a constant linear speed of 0.51~1m / min and a contact pressure of 1.5~2kg / cm².

[0037] In step S2.2, the metal shielding tape 30 with an adhesive layer is aligned with the core wire wrapping body and longitudinally bonded. The bonding operation is achieved using a rolling mechanism under controlled line speed and contact pressure conditions. This ensures that the metal tape adheres uniformly and smoothly to the core wire surface in the axial direction, forming a continuous and closed shielding middle layer structure. Compared to traditional transverse winding structures, the longitudinal wrapping structure is more compact on the physical contact surface, avoiding problems such as uneven thickness, edge warping, and impedance discontinuities in the high-frequency signal propagation path during winding and lamination. This helps improve the insertion loss consistency and electromagnetic interference shielding capability of the entire cable during high-frequency signal transmission.

[0038] In one embodiment, at least two core wire wraps and a ground wire 50 can be bonded together with a metal shielding strip. If a wide metal shielding strip is used, two core wire wraps and a ground wire 50 can be wrapped simultaneously, creating a more compact multi-core or symmetrical structure, which is beneficial for spatial wiring and interference cancellation design, and is particularly suitable for differential signal cables in communication, power or high-speed interconnect structures.

[0039] S2.3 After bonding, place it in a constant temperature drying oven, set the temperature to 130~150℃, and keep it warm for 5~10 seconds to form the middle layer structure of the longitudinal shielded cable.

[0040] In step S2.3, the longitudinally bonded metal shielding structure is placed in a constant-temperature drying oven for thermosetting under set temperature conditions. This process promotes chemical cross-linking of the adhesive, forming a stable bonding layer that firmly adheres the shielding tape to the core wire surface and seals the internal structure. For epoxy-modified acrylate or polyurethane thermosetting adhesives, the thermosetting process not only forms a cross-linked three-dimensional network, improving bond strength, but also enhances interfacial heat resistance and structural fatigue resistance, preventing structural failures such as warping, cracking, or delamination during long-term cable laying and use. The resulting longitudinally shielded cable's middle layer structure possesses a stable shielding path, electrical continuity, and physical support capabilities, which are crucial for high-frequency signal integrity transmission and external interference suppression.

[0041] S3. Wrap a flexible protective film 40 around the surface of the metal shielding tape 30 in the middle layer structure of the longitudinal shielded cable, then spray an elastomer coating liquid to form a protective film layer, and place it at 80°C for 2~5 minutes to complete the curing, thus obtaining a parallel single ground wire 50 metal shielded tape cable.

[0042] Step S3 includes: S3.1 Wrap the flexible protective film 40 around the surface of the metal shielding tape 30 of the middle layer structure of the longitudinal shielded cable, uniformly spray foamed gel on the surface of the flexible protective film 40, heat to 120~150℃, and hold for 5~10 seconds to form a buffer coating; the flexible protective film 40 includes at least one of fluorosilicone elastic film, polyimide polyurethane composite film, and fluorinated polyether film, and the foamed gel includes at least one of polyurethane elastic foamed gel, organosilicon foamed gel, and acrylate foamed gel.

[0043] In step S3.1, the flexible protective film 40 is wrapped around the surface of the metal shielding tape 30 of the longitudinal shielded cable's middle layer structure. This provides basic mechanical protection, scratch resistance, and a certain degree of moisture barrier without significantly increasing the cable's thickness. The fluorosilicone elastic film has extremely low surface energy and good flexibility, providing excellent waterproof and acid-resistant protection while maintaining adhesion. The polyimide-polyurethane composite film combines the high-temperature resistance of polyimide with the elasticity of polyurethane, exhibiting excellent folding resistance and fatigue resistance. The fluorinated polyether film displays extremely high chemical inertness and excellent gas barrier properties, making it particularly suitable for shielding structures in corrosive gas environments. Furthermore, a foaming gel, such as polyurethane elastic foaming gel, silicone foaming gel, or acrylate foaming gel, is uniformly sprayed onto the surface of the flexible protective membrane 40. When heated at a medium temperature, a buffer layer with a closed-cell structure is formed. This layer can absorb stress, buffer interlayer shear strain, and inhibit interface peeling under conditions of cable bending, impact, or thermal expansion and contraction. This significantly extends the service life of the cable in highly flexible environments and prevents stress concentration or fatigue cracks from appearing in the shielding layer during long-term use.

[0044] S3.2. Evenly spray the elastomer coating liquid onto the surface of the buffer coating. After spraying, heat to 80℃ and dry for 2-5 minutes to complete curing, obtaining a parallel single-ground wire 50mm metal shielded cable. The elastomer coating liquid includes at least one of perfluoroelastomer coating liquid, organosilicon polyurethane hybrid elastomer coating liquid, and fluorosilicone elastomer coating liquid.

[0045] In step S3.2, an elastomer coating liquid is uniformly sprayed onto the surface of the buffer coating to further form the outermost protective film layer, which can significantly improve the overall protection capability of the entire cable against acid mist, salt spray, water vapor, ultraviolet rays, and chemical corrosive media. The perfluorinated elastomer coating liquid possesses high molecular stability and chemical inertness, and after curing, it can form a surface barrier that is highly resistant to extreme media (such as nitric acid, hydrofluoric acid, and alkaline solutions), and has good hydrophobicity and antifouling properties. The organosilicon-polyurethane hybrid elastomer coating liquid combines the heat resistance and weather resistance of silicon with the flexibility of polyurethane, achieving a balance between UV aging resistance and flexible surface protection. The fluorosilicone elastomer coating liquid, due to its high surface tension and excellent flexible adhesion, can form a self-cleaning, dust-resistant, and antistatic elastic protective film. Curing the coating using a low-temperature drying process at 80 degrees Celsius not only avoids thermal damage to the underlying buffer layer but also ensures that the coating forms a uniform film without shrinkage or cracking, thus forming an integrated, highly flexible, and durable outer protective system. The resulting parallel single-ground wire 50 metal shielded cable not only possesses high-frequency performance and structural flexibility, but also boasts high-level environmental adaptability and long-term operational reliability.

[0046] This invention proposes a parallel single-ground wire 50mm metal shielded cable, which is manufactured by a method for preparing a parallel single-ground wire 50mm metal shielded cable.

[0047] Example 1: In step S1.1, 5g of nano-alumina particles are dispersed in 100g of ethyl acetate, and 1g of propyltriethoxysilane isocyanate is added as a modifier. The mixture is stirred at 70°C for 30 minutes and then dried under normal pressure for 24 hours to obtain a surface-modified reinforcing filler.

[0048] In S1.2, vinyl-terminated polydimethylsiloxane was selected as component A, with a mass of 100g; bisfluoropropylene-based polyfunctional silane and hydrogen-containing silicone oil were selected as component B, wherein the crosslinking agent bisfluoropropylene-based polyfunctional silane had a mass of 100g, and the amount of hydrogen-containing silicone oil was 5g, with a mass ratio of 100:100:5. The dried reinforcing filler was slowly added to component A, and dispersed by stirring at 2000rpm for 3 minutes, followed by degassing at 800rpm for 5 minutes. Subsequently, component B was added, and the mixture was mixed and degassed again for 5 minutes to obtain the reinforced liquid rubber.

[0049] In S1.3, the reinforced liquid rubber is coated onto the conductor surface, heated to 180°C, the vulcanization time is set to 20 minutes, and the heating rate is 2.5°C / min, to obtain a dense and uniform core wire wrapping.

[0050] Example 2: In S1.1, 4g of nano-zirconia particles were dispersed in 100g of acetone, and 1g of ethyl carbamate propyltriethoxysilane was added as a modifier. The mixture was stirred at 60°C for 30 minutes and dried under normal pressure to obtain the reinforcing filler.

[0051] In S1.2, hydroxyl-terminated polydimethylsiloxane was selected as component A (100g), and component B included propyltrimethoxysilane (100g), with a ratio of 100:100:5. The resulting A / B mixture was placed under a magnetron-controlled rotating electric field with a frequency of 0.5–5Hz and a voltage of 20–50V for 3–5 minutes. In this embodiment, a sinusoidal AC electric field with a frequency of 3Hz and a voltage of 40V was applied for 4 minutes. This caused the surface-modified nano-alumina to align axially within the polydimethylsiloxane segments, forming a pseudo-liquid crystal array structure. Subsequently, it was exposed to a 370nm wavelength ultraviolet light source for photocrosslinking for 2 minutes to initially fix the alignment structure, resulting in a semi-cured reinforced rubber system with a pre-aligned nanofiller structure. The remaining operating parameters were consistent with those in Example 1.

[0052] In S1.3, the core wire is vulcanized at 160℃ for 25 minutes with a heating rate controlled at 2℃ / min, resulting in a well-coated core wire sheath.

[0053] Example 3: In step S1.1, 3g of nano-silica particles were added to 100g of cyclohexanone, and 1g of propyltriethoxysilane was used as a modifier. The mixture was stirred at 50°C for 30 minutes and then dried under normal pressure. Component A consisted of 100g of fluorinated polysiloxane, and component B consisted of 100g of difluoropropylene-based multifunctional silane. The amount of hydrogen-containing silicone oil was 6g, and the ratio of the three components was 100:100:6. After degassing of the A / B mixture, 1g of trihydroxypropylsilane and 1g of fluoropropyltriethoxysilane were further introduced, and the mixture was slowly stirred at 600rpm for 2 minutes. Trihydroxypropylsilane, as a dynamic crosslinking precursor, generated reversible silanol-siloxane (Si–OH / Si–O–Si) bonds under subsequent heating and micro-humidity conditions. Fluoropropylsilane, through its fluoroalkyl chains, formed low surface energy regions between the polysiloxane chains, thereby constructing an elastic network structure with self-regulating interfacial energy at the microscale.

[0054] In S1.3, the film is formed by holding at 170℃ for 30 minutes and the heating rate is 2.8℃ / min.

[0055] Comparative Example 1: Compared to Example 1, no modifier was added; only unmodified nano-alumina particles were used as reinforcing fillers. All other steps were identical. The results showed reduced mixing uniformity, microcracks appearing on the surface of the inclusions, and decreased electrical strength after vulcanization.

[0056] Comparative Example 2: Compared with Example 2, the heating rate was not strictly controlled after using reinforcing filler and components A and B, and the heating rate reached 10°C / min. Although the vulcanization time was the same, bubbles and edge peeling appeared in the inclusions.

[0057] To test the electrical properties of the prepared reinforced liquid rubber material under different embodiments, corresponding core wire coating samples were prepared according to the formulations of Examples 1 to 3 and Comparative Examples 1 and 2, respectively. After each sample was vulcanized at 180°C or a corresponding temperature, it was cut to the sample size conforming to GB / T1695 standard.

[0058] First, the breakdown strength of each sample was tested using a high-voltage withstand voltage tester. The test was conducted in a constant voltage ramp mode, with the voltage ramp rate controlled at 500V / s, until the material broke down, and the electrical breakdown strength (in kV / mm) was recorded.

[0059] Subsequently, the volume resistivity of each sample was measured using a volume resistivity meter according to the GB / T1410 standard at a DC voltage of 500V. The ambient temperature was controlled at 25±2℃ and the humidity was below 50%RH.

[0060] The experimental data are shown in Table 1.

[0061] Table 1: Experimental data show that Example 2, which uses a magnetron-controlled rotating electric field to induce the directional arrangement of fillers and combines it with ultraviolet light crosslinking, significantly improves the electrical strength and interfacial density of the coating. The electrical breakdown strength increases from 17.6 kV / mm in Example 1 to 21.3 kV / mm, demonstrating that the directional arrangement structure can effectively suppress the propagation of internal defects and stress concentration.

[0062] Example 3 introduces fluoropropylsilane and trihydroxypropylsilane to construct a dynamically reversible cross-linked, low surface energy network, which also has a better resistivity than Example 1, indicating that this molecular structure design helps the overall stability and stress release of the material.

[0063] Comparative Example 1 did not use a modifier, resulting in poor filler dispersion, uneven filling effect, and a decrease in electrical strength to 12.2 kV / mm; while Comparative Example 2 had modified fillers, but the heating rate was out of control (reaching 10℃ / min). Controlling the heating rate is also a key variable to ensure the quality of vulcanization.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation method, characterized in that, The steps for preparing parallel single-ground wire metal shielded cables include: S1. A modified insulation layer is coated on the surface of the conductor and heated to 150~200℃ for hot vulcanization for 10~30 minutes to obtain the core wire wrapping, wherein the modified insulation layer includes an insulation matrix and reinforcing filler; S2. Coat the two sides of the metal shielding tape with a corrosion-resistant layer and an adhesive layer respectively to obtain the metal shielding tape. Wrap the metal shielding tape longitudinally on the surface of the core wire covering body and bond it by a rolling mechanism. Heat cure it at 130~150°C for 5~10 seconds to form the middle layer structure of the longitudinal shielded cable. S3. Wrap a flexible protective film around the surface of the metal shielding tape in the middle layer of the longitudinal shielded cable, then spray an elastomer coating liquid to form a protective film layer, and dry it at 80°C for 2-5 minutes to complete the curing, thus obtaining a parallel single-ground wire metal shielded cable.

2. The preparation method according to claim 1, characterized in that, Step S1 includes: S1.1 Disperse the filler raw material in an organic solvent, add a modifier, stir at 50~80℃ for 30 minutes, and then dry under normal pressure to obtain the reinforced filler; S1.

2. Determine the insulating matrix as component A, and the crosslinking agent and hydrogen-containing silicone oil as component B. Slowly add the reinforcing filler to component A in a dry state for dispersion and mixing. Set the mixing conditions to a dispersion process with a stirring speed of 2000 rpm and a degassing process with a stirring speed of 800 rpm. The mixing time is 5-8 minutes. Then add component B to component A and reinforcing filler and mix them at a weight ratio of 100:100:(3-8). Perform secondary mixing and degassing again for 3-5 minutes to obtain reinforced liquid rubber. S1.

3. Apply reinforced liquid rubber to the conductor surface to form a modified insulation layer, heat to 150~200℃ and vulcanize for 10~30 minutes, keeping the heating rate within 3℃ / min to obtain the core wire wrapping.

3. The preparation method according to claim 2, characterized in that, In step S1, the filler raw material includes at least one of nano-alumina particles, nano-silica particles, and nano-zirconia particles; the insulating matrix includes at least one of vinyl-terminated polydimethylsiloxane, hydroxyl-terminated polydimethylsiloxane, and fluorinated polysiloxane; and the crosslinking agent includes at least one of difluoropropylene-based polyfunctional silane, propyltriethoxysilane isocyanate, propyltrimethoxysilane isocyanate, and ethyl carbamate propyltriethoxysilane.

4. The preparation method according to claim 1, characterized in that, Step S2 includes: S2.1 Place the metal shielding tape in a mixture of ethanol and acetone and ultrasonically clean it for 10 minutes. After hot air drying, apply a corrosion-resistant coating sol to one side of the metal shielding tape. After hot pressing, a corrosion-resistant layer is formed. Apply an adhesive to the side of the metal shielding tape away from the corrosion-resistant layer to form an adhesive layer. S2.2 Align the adhesive layer of the metal shielding tape with the core wire wrapping body, and longitudinally bond it along the axial direction of the core wire wrapping body using a rolling mechanism at a constant linear speed of 0.51~1m / min and a contact pressure of 1.5~2kg / cm². S2.3 After bonding, place it in a constant temperature drying oven, set the temperature to 130~150℃, and keep it warm for 5~10 seconds to form the middle layer structure of the longitudinal shielded cable.

5. The preparation method according to claim 4, characterized in that, In step S2, the metal shielding strip includes at least one of aluminum-nickel alloy, tin-plated copper foil, and stainless steel; the corrosion-resistant coating sol includes at least one of titanium dioxide-doped silica sol, zirconium oxide-silica composite sol, fluorosilica hybrid sol, cerium-doped silica sol, and phosphorus-silica hybrid sol; and the adhesive includes at least one of epoxy-modified acrylate adhesive, polyurethane thermosetting adhesive, polyimide structural adhesive, and polyesteramide copolymer.

6. The preparation method according to claim 1, characterized in that, Step S3 includes: S3.1 Wrap the flexible protective film around the surface of the metal shielding tape in the middle layer of the longitudinal shielded cable, spray foamed gel evenly on the surface of the flexible protective film, heat to 120~150℃, hold for 5~10 seconds to form a buffer coating. S3.

2. Spray the elastomer coating liquid evenly onto the surface of the buffer coating. After spraying, heat to 80℃ and dry for 2-5 minutes to complete the curing, and obtain a parallel single-ground wire metal shielded cable.

7. The preparation method according to claim 6, characterized in that, In step S3, the flexible protective film includes at least one of fluorosilicone elastic film, polyimide polyurethane composite film, and fluorinated polyether film; the foaming gel includes at least one of polyurethane elastic foaming gel, silicone foaming gel, and acrylate foaming gel; and the elastomer coating liquid includes at least one of perfluorinated elastomer coating liquid, silicone polyurethane hybrid elastomer coating liquid, and fluorosilicone elastic coating liquid.

8. A parallel single-ground wire metal-shielded cable, characterized in that, The parallel single-ground wire metal shielded cable, manufactured by the preparation method described in any one of claims 1-7, comprises a metal shielding tape and core wire wrapping bodies, wherein the metal shielding tape is longitudinally wrapped around at least two core wire wrapping bodies.

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