Double-layer co-extrusion sheath cable
By using a double-layer co-extruded sheath structure, the synergistic effect of the inner and outer sheath layers solves the problem of insufficient flame retardancy and mechanical strength of traditional cables in high flame retardant scenarios, and realizes a cable design that provides efficient flame retardancy and mechanical protection.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-06
- Publication Date
- 2026-04-03
AI Technical Summary
Traditional high-voltage cable outer sheath materials suffer from insufficient flame retardancy and mechanical strength in high flame retardant scenarios. Single-layer PVC sheaths are prone to softening, while single-layer MDPE sheaths have poor toughness and are prone to cracking.
It adopts a double-layer co-extruded sheath structure. The inner sheath layer is made of flame-retardant PVC material, and the outer sheath layer is made of high-hardness MDPE material. They are formed simultaneously through co-extrusion process. The inner sheath layer forms a carbonized layer at high temperature to prevent the spread of flames, while the outer sheath layer provides mechanical protection. The two layers are also enhanced by fusion bonding.
It achieves an overall flame retardant rating of V-0 for the cable, improves impact resistance by 30%, significantly enhances mechanical strength, is suitable for outdoor high temperature and high humidity environments, reduces material costs by 15%-20%, and increases production efficiency.
Smart Images
Figure CN224082219U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of cable manufacturing technology, specifically to a double-layer co-extruded sheathed cable. Background Technology
[0002] Wires and cables are wire products used to transmit electrical (magnetic) energy, information, and realize the conversion of electromagnetic energy. In a broad sense, wires and cables are also simply referred to as cables. In a narrow sense, cables refer to insulated cables, which can be defined as: an assembly consisting of one or more insulated cores, and their respective possible covering layers, overall protective layer, and outer sheath.
[0003] Traditional high-voltage cables typically use a single-layer outer sheath structure (such as pure PVC or pure MDPE). While single-layer PVC sheaths are flame-retardant, they soften easily at high temperatures, failing to meet the requirements of high flame-retardant applications. Single-layer MDPE sheaths lack sufficient mechanical strength and toughness, making them prone to cracking due to external impacts or environmental stress. Therefore, a double-layer co-extruded sheath cable is proposed. Utility Model Content
[0004] To address the shortcomings of existing technologies, this application provides a double-layer co-extruded sheathed cable with improved flame retardancy and optimized mechanical strength.
[0005] To achieve the above objectives, this application provides the following technical solution: a double-layer co-extruded sheathed cable, comprising, from the inside out, a conductor, a conductor shielding layer, a cross-linked polyethylene insulation layer, an insulation shielding layer, a semi-conductive resistive water tape, a soft round copper wire, a soft pure copper tape, a non-conductive resistive water tape, and a CPP tape. The outermost layer of the conductor is a double-layer co-extruded sheath structure, which includes an inner sheath layer and an outer sheath layer. The inner sheath layer is disposed outside the CPP tape. The inner sheath layer is made of flame-retardant PVC material, and the outer sheath layer is made of high-hardness MDPE material. The two are formed simultaneously through a co-extrusion process.
[0006] The above solution, through the setting of an inner sheath layer and an outer sheath layer, utilizes flame-retardant PVC material with an oxygen index ≥32% for the inner sheath layer. Under high temperature or open flame conditions, it can rapidly form a carbonized layer, effectively isolating oxygen and releasing flame-retardant gases, preventing the flame from spreading into the cable. The outer sheath layer uses high-hardness MDPE material, which, although its inherent flame retardancy is generally average, can slow down the flame spread rate. Working synergistically with the inner PVC layer, it enables the overall flame retardancy rating of the cable to reach V-0 (UL 94 standard), meeting the requirements of high flame retardancy scenarios, thus significantly improving the flame retardant performance. The outer sheath layer uses MDPE material with a tensile strength ≥20MPa and an elongation at break ≥500%, improving impact resistance by more than 30%, effectively resisting external impacts, compression, and environmental stress cracking (cracking resistance time ≥2000h, ASTM). D1693), CPP tape as the inner lining layer (thickness 0.2-0.5mm, density 0.89-0.91g / cm³), provides additional mechanical support to prevent sheath deformation. At the same time, it is thermally fused with the inner sheath layer (peel strength ≥1.5N / mm) to ensure tight adhesion between layers, avoid slippage or delamination during laying, and thus greatly enhance mechanical strength.
[0007] Furthermore, the inner sheath layer has a thickness of 0.8-1.2 mm, and the outer sheath layer has a thickness of 1.5-2.0 mm.
[0008] With the above scheme, the inner sheath layer thickness is 0.8-1.2mm: ensuring flame retardancy while maintaining flexibility, and the outer sheath layer thickness is 1.5-2.0mm: providing sufficient mechanical protection.
[0009] Furthermore, the flame-retardant PVC material of the inner sheath layer has an oxygen index ≥32%.
[0010] With the above solution, the oxygen index of the inner sheath layer is ≥32%, which achieves the V-0 flame retardant standard and effectively inhibits the spread of flame.
[0011] Furthermore, the MDPE material of the outer sheath layer has a tensile strength ≥20MPa and an elongation at break ≥500%.
[0012] With the above solution, the tensile strength of the outer sheath is ≥20MPa, the elongation at break is ≥500%, the impact resistance is improved by more than 30%, and it is resistant to environmental stress cracking.
[0013] Furthermore, an anti-ultraviolet additive is added to the surface of the outer sheath layer, achieving a weather resistance rating of UV-A.
[0014] With the above solution, the outer sheath layer is added with UV-A grade anti-ultraviolet additives, which can withstand strong ultraviolet radiation for a long time, increase the anti-aging life by 50%, and is suitable for outdoor, high temperature (-40℃~90℃) and high humidity environments.
[0015] Furthermore, the inner and outer layers of the double-layer co-extruded sheath structure form a molten interface bond with a bonding strength ≥3N / mm².
[0016] The above solution achieves an interfacial fusion bonding strength of ≥3N / mm², avoiding the risk of interlayer delamination caused by traditional step extrusion.
[0017] Furthermore, the co-extrusion process temperature of the inner sheath layer and the outer sheath layer is 180-200℃ for the inner layer and 200-220℃ for the outer layer.
[0018] Through the above scheme, the double-layer co-extruded sheath structure is formed simultaneously through the co-extrusion process (inner layer 180-200℃, outer layer 200-220℃). Compared with single-layer modified sheath materials, the double-layer structure reduces material costs by 15%-20% while ensuring performance, and has higher production efficiency.
[0019] Furthermore, the CPP tape and the inner sheath layer are bonded together by hot fusion, with an interfacial peel strength ≥1.5N / mm (GB / T2790 standard), and the CPP tape has a thickness of 0.2-0.5mm and a density of 0.89-0.91g / cm³.
[0020] The above-mentioned solution ensures sufficient mechanical support with its specific thickness (0.2-0.5mm) and density (0.89-0.91g / cm³) without excessively increasing the weight of the cable.
[0021] Compared with the prior art, the technical solution of this application has the following beneficial effects:
[0022] 1. This double-layer co-extruded sheathed cable features an inner sheath and an outer sheath. The inner sheath uses flame-retardant PVC material with an oxygen index ≥32%, which rapidly forms a carbonized layer under high temperature or open flame conditions, effectively isolating oxygen and releasing flame-retardant gases to prevent the flame from spreading into the cable. The outer sheath uses high-hardness MDPE material, which, while having moderate flame retardancy, slows the flame spread. Working synergistically with the inner PVC layer, this achieves an overall flame retardancy rating of V-0 (UL 94 standard), meeting the requirements of high flame retardancy scenarios and significantly improving flame retardant performance. The outer sheath uses MDPE material with a tensile strength ≥20MPa and elongation at break ≥500%, improving impact resistance by over 30% and effectively resisting external impacts, compression, and environmental stress cracking (cracking resistance time ≥2000h, ASTM standard). D1693), CPP tape as the inner lining layer (thickness 0.2-0.5mm, density 0.89-0.91g / cm³), provides additional mechanical support to prevent sheath deformation. At the same time, it is thermally fused with the inner sheath layer (peel strength ≥1.5N / mm) to ensure tight adhesion between layers, avoid slippage or delamination during laying, and thus greatly enhance mechanical strength.
[0023] 2. This double-layer co-extruded sheathed cable features an outer sheath layer with added UV-A grade additives, enabling it to withstand strong ultraviolet radiation for extended periods and increasing its anti-aging lifespan by 50%. It is suitable for outdoor, high-temperature (-40℃~90℃), and high-humidity environments. The non-conductive and semi-conductive water-resistant tapes form a "longitudinal + radial" dual water-blocking structure, which, combined with the waterproof performance of the CPP tape, effectively prevents water penetration. It is suitable for submarine cables or wet underground installations. The double-layer co-extruded sheath structure is formed simultaneously through a co-extrusion process (inner layer 180-200℃, outer layer 200-220℃), achieving an interfacial fusion bonding strength ≥3N / mm². This avoids the risk of interlayer delamination caused by traditional step-by-step extrusion. Compared to single-layer modified sheath materials, the double-layer structure reduces material costs by 15%-20% while maintaining performance, and also offers higher production efficiency. Attached Figure Description
[0024] Figure 1 This is a three-dimensional structural diagram of the present application.
[0025] Figure 2 This is a cross-sectional schematic diagram of the solid structure of this application;
[0026] Figure 3 This is a process flow diagram of the double-layer co-extrusion sheath of this application;
[0027] Figure 4 This is a process flow diagram of the CPP tape and sheath bonding process in this application;
[0028] Figure 5 This is a flowchart showing the relationship between material parameters and processes in this application.
[0029] In the picture:
[0030] 1. Conductor; 2. Conductor shielding layer; 3. Cross-linked polyethylene insulation layer; 4. Insulating shielding layer; 5. Semi-conductive resistive water tape; 6. Soft round copper wire; 7. Soft pure copper tape; 8. Non-conductive resistive water tape; 9. CPP tape; 10. Double-layer co-extruded sheath structure; 101. Inner sheath layer; 102. Outer sheath layer. Detailed Implementation
[0031] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0032] Please see Figure 2 , Figure 3 and Figure 4This embodiment of a double-layer co-extruded sheathed cable includes, from the inside out, a conductor 1, a conductor shielding layer 2, a cross-linked polyethylene insulation layer 3, an insulation shielding layer 4, a semi-conductive resistive water tape 5, a soft round copper wire 6, a soft pure copper tape 7, a non-conductive resistive water tape 8, and a CPP tape 9. The outermost layer of the conductor 1 is a double-layer co-extruded sheath structure 10, which includes an inner sheath layer 101 and an outer sheath layer 102. The inner sheath layer 101 is disposed outside the CPP tape 9 and is made of flame-retardant PVC material. The outer sheath layer 102 is made of high-hardness PVC material. Both the inner and outer sheaths are made of high-hardness MDPE material and are simultaneously formed through a co-extrusion process. The cable consists of an inner sheath layer 101 and an outer sheath layer 102. The inner sheath layer 101 is made of flame-retardant PVC material with an oxygen index ≥32%, which can rapidly form a carbonized layer under high temperature or open flame conditions, effectively isolating oxygen and releasing flame-retardant gases to prevent the flame from spreading into the cable. The outer sheath layer 102 is made of high-hardness MDPE material, which, although its own flame retardancy is relatively low, can slow down the flame spread rate. Working synergistically with the inner PVC layer, the overall flame retardant rating of the cable reaches V-0 (UL) level. The outer sheath layer 102 is made of MDPE material with a tensile strength ≥20MPa and an elongation at break ≥500%, which improves the impact resistance by more than 30% and can effectively resist external impact, extrusion and environmental stress cracking (cracking resistance time ≥2000h, ASTM D1693). The CPP tape 9 serves as the inner lining layer (thickness 0.2-0.5mm, density 0.89-0.91g / cm³), providing additional mechanical support to prevent sheath deformation. At the same time, it is heat-fused to the inner sheath layer 101 (peel strength ≥1.5N / mm) to ensure tight adhesion between layers and avoid slippage or delamination during laying, thereby greatly enhancing mechanical strength.
[0033] Please see Figure 2 , Figure 3 and Figure 4 The inner sheath layer 101 has a thickness of 0.8-1.2mm, and the outer sheath layer 102 has a thickness of 1.5-2.0mm. The flame-retardant PVC material of the inner sheath layer 101 has an oxygen index ≥32%, and the MDPE material of the outer sheath layer 102 has a tensile strength ≥20MPa and an elongation at break ≥500%. The thickness of the inner sheath layer 101 (0.8-1.2mm) ensures both flame retardancy and flexibility, while the thickness of the outer sheath layer 102 (1.5-2.0mm) provides sufficient mechanical protection. The oxygen index of the inner sheath layer ≥32% achieves the V-0 flame retardant standard, effectively inhibiting flame spread. The tensile strength of the outer sheath layer 102 ≥20MPa and the elongation at break ≥500% improve impact resistance by more than 30% and resist environmental stress cracking.
[0034] Please see Figure 2 , Figure 3 and Figure 4The outer sheath layer 102 has an added UV-resistant additive, achieving a weather resistance rating of UV-A. The inner and outer layers of the double-layer co-extruded sheath structure 10 form a molten interface bond with a bonding strength ≥3 N / mm². The co-extrusion process temperature for the inner sheath layer 101 and outer sheath layer 102 is 180-200℃ for the inner layer and 200-220℃ for the outer layer. The CPP strip 9 is hot-melt bonded to the inner sheath layer 101, with an interface peel strength ≥1.5 N / mm (GB / T). The CPP tape 9 is 0.2-0.5mm thick and 0.89-0.91g / cm³, conforming to the 2790 standard. The outer sheath layer 102 is treated with UV-A additives, enabling it to withstand strong UV radiation for extended periods and increasing its anti-aging lifespan by 50%. It is suitable for outdoor, high-temperature (-40℃~90℃), and high-humidity environments. The interface fusion bonding strength is ≥3N / mm², avoiding the risk of interlayer delamination caused by traditional step extrusion. The double-layer co-extruded sheath structure 10 is formed simultaneously through a co-extrusion process (inner layer 180-200℃, outer layer 200-220℃). Compared to single-layer modified sheath materials, the double-layer structure reduces material costs by 15%-20% while maintaining performance and has higher production efficiency. Its specific thickness (0.2-0.5mm) and density (0.89-0.91g / cm³) ensure sufficient mechanical support without excessively increasing the cable weight.
[0035] In this embodiment, by setting an inner sheath layer 101 and an outer sheath layer 102, the inner sheath layer 101 is made of flame-retardant PVC material with an oxygen index ≥32%. Under high temperature or open flame conditions, it can quickly form a carbonized layer, effectively isolating oxygen and releasing flame-retardant gases, preventing the flame from spreading into the cable. The outer sheath layer 102 is made of high-hardness MDPE material. Although its flame retardancy is generally average, it can slow down the flame spread rate. Working synergistically with the inner PVC layer, it enables the overall flame retardancy rating of the cable to reach V-0 (UL 94 standard), meeting the requirements of high flame retardancy scenarios, thus significantly improving the flame retardancy performance. The outer sheath layer 102 is made of MDPE material with a tensile strength ≥20MPa and an elongation at break ≥500%, which improves the impact resistance by more than 30%. It can effectively resist external impact, extrusion, and environmental stress cracking (cracking resistance time ≥2000h, ASTM). D1693), CPP tape 9 serves as the inner lining layer (thickness 0.2-0.5mm, density 0.89-0.91g / cm³), providing additional mechanical support to prevent sheath deformation. At the same time, it is heat-fused to the inner sheath layer 101 (peel strength ≥1.5N / mm) to ensure tight adhesion between layers, preventing slippage or delamination during laying, thereby significantly enhancing mechanical strength.
[0036] The working principle of the above embodiment is as follows: The inner sheath layer 101 is made of flame-retardant PVC material. When the cable encounters high temperature or open flame, this layer will quickly form a dense carbonized layer, effectively isolating oxygen and releasing flame-retardant gas, preventing the flame from spreading into the cable. The outer sheath layer 102 is made of high-hardness MDPE material, which provides mechanical protection through its high crystallinity structure, resisting external impact and compression. At the same time, its hydrophobic properties can prevent water penetration. The flame-retardant properties of the inner PVC layer and the fire-retardant properties of the outer MDPE layer form a synergistic effect: PVC quickly forms a flame-retardant barrier, while MDPE delays the spread of fire through its high melting point, so that the overall flame-retardant performance reaches the V-0 standard. The UV-resistant additives added to the outer MDPE layer can absorb and scatter ultraviolet rays, protecting the cable from solar aging. The non-conductive water-resistant tape 8 and the semi-conductive water-resistant tape 5 form a two-way waterproof barrier to prevent water penetration from damaging the insulation. Performance degradation is mitigated by the CPP tape 9 serving as a transition layer. Its specific thickness (0.2-0.5mm) and density (0.89-0.91g / cm³) ensure sufficient mechanical support without excessively increasing cable weight. The CPP tape and inner sheath are bonded together with high strength (peel strength ≥1.5N / mm) through a hot-melt process, ensuring no separation between layers. The co-extrusion process (inner layer 180-200℃, outer layer 200-220℃) enables the two materials with different properties to achieve molecular-level bonding in the molten state, with an interface bonding strength ≥3N / mm². This ensures structural integrity and improves production efficiency. The conductor shielding layer 2 and the insulation shielding layer 4 ensure uniform electric field distribution and prevent partial discharge. The cross-linked polyethylene insulation layer 3 provides stable insulation performance, and its high dielectric strength can withstand high-voltage electric fields. The soft pure copper tape 7 and the soft round copper wire 6 together constitute a composite shielding structure.
[0037] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.
[0038] Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A double-layer co-extrusion sheath cable, comprising, from inside to outside, a conductor (1), a conductor shield layer (2), a cross-linked polyethylene insulation layer (3), an insulation shield layer (4), a semi-conductive water-blocking tape (5), a soft round copper wire (6), a soft pure copper tape (7), a non-conductive water-blocking tape (8) and a CPP tape (9), characterized in that: The outermost layer of the conductor (1) is a double-layer co-extrusion sheath structure (10), which comprises an inner sheath layer (101) and an outer sheath layer (102), the inner sheath layer (101) is arranged outside the CPP tape (9), the inner sheath layer (101) is made of flame-retardant PVC material, and the outer sheath layer (102) is made of high-hardness MDPE material, and the two are synchronously formed through a co-extrusion process.
2. A dual layer co-extruded jacketed cable according to claim 1, characterized in that: The thickness of the inner sheath layer (101) is 0.8-1.2mm, and the thickness of the outer sheath layer (102) is 1.5-2.0mm.
3. A dual layer co-extruded jacketed cable according to claim 1, characterized in that: The oxygen index of the flame-retardant PVC material of the inner sheath layer (101) is greater than or equal to 32%.
4. A dual layer co-extruded jacketed cable according to claim 1, characterized in that: The tensile strength of the MDPE material of the outer sheath layer (102) is greater than or equal to 20MPa, and the elongation at break is greater than or equal to 500%.
5. A dual layer co-extruded jacketed cable according to claim 1, characterized in that: An anti-ultraviolet aid is added to the surface of the outer sheath layer (102), and the weather resistance grade reaches UV-A level.
6. A dual layer coextruded jacketed cable according to claim 1, characterized in that: The inner layer and the outer layer of the double-layer co-extrusion sheath structure (10) are combined through a molten interface, and the bonding strength is greater than or equal to 3N / mm².
7. A dual layer co-extruded jacketed cable according to claim 1, characterized in that: The co-extrusion process temperature of the inner sheath layer (101) and the outer sheath layer (102) is 180-200℃ for the inner layer and 200-220℃ for the outer layer.
8. A dual layer co-extruded jacketed cable according to claim 1, characterized in that: The CPP tape (9) and the inner sheath layer (101) are combined through hot melting, the interface peeling strength is greater than or equal to 1.5N / mm (GB / T 2790 standard), and the thickness of the CPP tape (9) is 0.2-0.5mm, and the density is 0.89-0.91g / cm³.