High-temperature-resistant halogen-free low-smoke flame-retardant stranded flexible cord and preparation process thereof

Abstract

This invention relates to the field of wire technology, specifically to a high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire and its manufacturing process. The wire comprises a conductor, an insulation layer, a flame-retardant layer, and an outer sheath. By employing a nitrogen-phosphorus composite flame retardant with the synergistic effect of nano-aluminum hydroxide / magnesium hydroxide, combined with zinc borate as a heat-absorbing agent and phosphorus-based free radical scavengers, a four-dimensional flame-retardant mechanism is constructed, significantly improving the material's flame-retardant efficiency and reducing the toxicity of combustion products. This meets the dual requirements of environmental protection and safety in high-end applications. Furthermore, a layered stranded conductor and integrated heat dissipation and airflow guiding structure are adopted. Through this layered stranded conductor design, the inner layer uses short-pitch tight stranding to ensure flexibility, while the outer layer uses unidirectional stranding to optimize roundness, enabling the wire's bending life to exceed 10,000 cycles. Combined with the spiral airflow guiding groove design of the halogen-free flame-retardant outer sheath, an air convection channel is formed, reducing the core temperature rise by more than 15°C, thus achieving a technical balance between high heat resistance and halogen-free, low-smoke characteristics.

Description

Technical Field

[0001] This invention relates to the field of wire technology, and in particular to a high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire and its manufacturing process. Background Technology

[0002] With the rapid development of highly concentrated urban buildings and networked rail transit, modern electrical systems have placed more stringent demands on the safety and reliability of electrical cables. Especially in densely populated areas and enclosed spaces, the heat resistance and flammability of electrical wires are directly related to the safety of life and property.

[0003] Currently, mainstream flexible electrical wire products generally face two major technical bottlenecks: First, the upper limit of long-term operating temperature is relatively low, making it difficult to meet the heat dissipation requirements of high-load electrical equipment during continuous operation; second, traditional flame-retardant materials release a large amount of toxic fumes and halogen acid gases under fire conditions, seriously threatening the safety of personnel evacuation and rescue.

[0004] Halogen-free, low-smoke cables must be used in densely populated areas and important buildings. However, existing flexible cables have significant shortcomings in achieving a technical balance between high heat resistance and halogen-free, low-smoke characteristics. Ordinary polyolefin materials have limited heat resistance, while high-performance elastomer materials face industrialization challenges such as high cost and complex processes. Summary of the Invention

[0005] The purpose of this invention is to provide a high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire and its manufacturing process, which solves the problem that existing flexible wires have significant shortcomings in achieving a technical balance between high heat resistance and halogen-free, low-smoke characteristics, and that ordinary polyolefin materials have limited heat resistance.

[0006] To achieve the above objectives, the present invention provides a high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire, comprising a conductor, an insulation layer, a flame-retardant layer, and an outer sheath. The insulation layer is connected to the conductor and located on one side of the conductor. The flame-retardant layer is connected to the insulation layer and located on one side of the insulation layer. The outer sheath is connected to the flame-retardant layer and located on one side of the flame-retardant layer.

[0007] A manufacturing process for a high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire includes the following steps: Prepare the materials for the fabrication of the wire; The conductors are stranded in layers; The insulating layer is extruded onto the conductor and cross-linked. The outer sheath is extruded onto the insulating layer and then cooled and shaped. Testing and packaging of finished wires The step of preparing the materials for the wire includes: The materials used in the preparation include conductor materials, insulating materials, flame-retardant materials, and sheathing materials.

[0008] The step of stranding the conductors in layers includes: The conductor adopts a layered stranded structure, with the inner conductor using short-pitch tight stranding and the outer conductor using unidirectional stranding.

[0009] The step of extruding an insulating layer onto the conductor and cross-linking it includes: The mixed insulating material is evenly wrapped around the conductor using a high-temperature extruder to form the initial insulating layer; After extrusion, the molecular chains are initially cross-linked using silane grafting technology; The initially cross-linked insulating layer is subjected to electron irradiation treatment.

[0010] The step of extruding the outer sheath onto the insulating layer and then cooling and shaping it includes: The mixed sheath material is evenly wrapped onto the insulation layer through a high-temperature extruder to form a sheath layer; The extruded sheath layer is cooled and shaped.

[0011] The process of inspecting and packaging finished wires includes the following steps: Perform performance testing on the finished wires; Wires that pass the inspection are packaged.

[0012] This invention discloses a high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire and its manufacturing process. By employing a nitrogen-phosphorus composite flame retardant and the synergistic effect of nano-aluminum hydroxide / magnesium hydroxide, combined with zinc borate endothermic agent and phosphorus-based free radical scavenger, a four-dimensional flame-retardant mechanism is constructed. This significantly improves the flame-retardant efficiency of the material, reduces the toxicity of combustion products, and meets the dual requirements of environmental protection and safety in high-end applications. Furthermore, it adopts a layered stranded conductor and integrated heat dissipation and airflow guiding structure. Through the layered stranded conductor structure design, the inner layer uses short-pitch tight stranding to ensure flexibility, while the outer layer uses unidirectional stranding to optimize roundness, enabling the wire's bending life to exceed 10,000 cycles. Combined with the spiral airflow guiding groove design of the halogen-free flame-retardant sheath, an air convection channel is formed, reducing the core temperature rise by more than 15°C, achieving a technical balance between the wire's high heat resistance and halogen-free, low-smoke characteristics. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0014] Figure 1This is a schematic diagram of the structure of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire according to the first embodiment of the present invention.

[0015] Figure 2 This is a flowchart illustrating the manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire according to the second embodiment of the present invention.

[0016] Figure 3 This is a flowchart illustrating the conductor layering and stranding steps of the second embodiment of the present invention.

[0017] Figure 4 This is a schematic diagram of the extrusion structure of the outer sheath according to the second embodiment of the present invention.

[0018] Figure 5 This is a flowchart illustrating the steps of wire inspection and packaging according to the second embodiment of the present invention.

[0019] In the diagram: 101 - conductor, 102 - insulation layer, 103 - flame retardant layer, 104 - outer sheath. Detailed Implementation

[0020] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0021] Please see Figure 1 ,in Figure 1 This is a schematic diagram of the structure of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire according to the first embodiment of the present invention.

[0022] The present invention provides a high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire, comprising a conductor 101, an insulation layer 102, a flame-retardant layer 103, and an outer sheath 104.

[0023] In this embodiment, the insulation layer 102 is connected to the conductor 101 and located on one side of the conductor 101; the flame-retardant layer 103 is connected to the insulation layer 102 and located on one side of the insulation layer 102; the outer sheath 104 is connected to the flame-retardant layer 103 and located on one side of the flame-retardant layer 103. The conductor 101 employs a layered stranded conductor structure design, with the inner layer using short-pitch tight stranding to ensure flexibility, and the outer layer using unidirectional stranding to optimize roundness, enabling the wire's bending life to exceed ten thousand cycles. Insulation layer 102 is made of high-performance halogen-free flame-retardant polyolefin material. Flame-retardant layer 103 utilizes a nitrogen-phosphorus composite flame retardant with the synergistic effect of nano-aluminum hydroxide / magnesium hydroxide, combined with zinc borate endothermic agent and phosphorus-based free radical scavenger, to construct a four-dimensional flame-retardant mechanism. This significantly improves the flame-retardant efficiency of the material, reduces the toxicity of combustion products, and meets the dual requirements of environmental protection and safety in high-end applications. The outer sheath 104 has a spiral channel for heat dissipation and drainage, forming an air convection channel that reduces the core temperature rise by more than 15°C. This wire constructs a "thermal" structure... The "force-electricity" multi-performance synergistic stranded conductor 101 system, in layered stranded conductor 101 structure flexible wires, achieves a balance between bending resistance and conductivity through gradient copper wire diameter configuration and optimized stranding pitch. Simultaneously, silane grafting achieves initial molecular chain cross-linking, followed by deep curing using electron irradiation, keeping the thermal elongation of the insulation layer 102 below 80%. Furthermore, a standardized process database is established to achieve closed-loop control of key parameters (temperature, tension, speed), increasing the product qualification rate to 99.6%. This is achieved through the adoption of... The synergistic effect of nitrogen-phosphorus composite flame retardant and nano-aluminum hydroxide / magnesium hydroxide, combined with zinc borate endothermic agent and phosphorus-based free radical scavenger, constructs the flame retardant layer 103 with a four-dimensional flame retardant mechanism. This significantly improves the flame retardant efficiency of the material, reduces the toxicity of combustion products, and meets the dual requirements of environmental protection and safety in high-end scenarios. It also employs a layered stranded conductor 101 integrated with a heat dissipation and airflow guiding structure. Through the layered stranded conductor 101 structural design, the inner layer uses short-pitch tight stranding to ensure flexibility, while the outer layer uses unidirectional stranding to optimize roundness, enabling the wire bending life to exceed 10,000 cycles. Combined with the spiral airflow guiding groove design of the outer sheath 104, a halogen-free flame retardant sheath with heat dissipation and airflow guiding grooves, an air convection channel is formed, reducing the core temperature rise by more than 15°C, thereby achieving a technical balance between high heat resistance and halogen-free, low-smoke characteristics.

[0024] When using the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire and its manufacturing process according to this embodiment, the flame-retardant layer 103, which has a four-dimensional flame-retardant mechanism, is constructed by using a nitrogen-phosphorus composite flame retardant and nano-aluminum hydroxide / magnesium hydroxide synergistically, combined with zinc borate endothermic agent and phosphorus-based free radical scavenger. This significantly improves the flame-retardant efficiency of the material, reduces the toxicity of combustion products, and meets the dual requirements of environmental protection and safety in high-end scenarios. Furthermore, it adopts a layered stranded conductor 101 integrated with a heat dissipation and airflow guiding structure. Through the layered stranded conductor 101 structural design, the inner layer uses short-pitch tight stranding to ensure flexibility, while the outer layer uses unidirectional stranding to optimize roundness, enabling the wire's bending life to exceed 10,000 cycles. Combined with the spiral airflow guiding groove design of the outer sheath 104, a halogen-free flame-retardant sheath with heat dissipation and airflow guiding grooves, an air convection channel is formed, reducing the core temperature rise by more than 15°C, thereby achieving a technical balance between high heat resistance and halogen-free, low-smoke characteristics.

[0025] The second embodiment of this application is as follows: Please see Figures 2-5 ,in Figure 2 This is a flowchart illustrating the manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire according to the second embodiment of the present invention. Figure 3 This is a flowchart illustrating the conductor layering and stranding steps of the second embodiment of the present invention. Figure 4 This is a schematic diagram of the extrusion structure of the outer sheath according to the second embodiment of the present invention. Figure 5 This is a flowchart illustrating the steps of wire inspection and packaging according to the second embodiment of the present invention.

[0026] Based on the first embodiment, the manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire described in this embodiment is applicable to the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire and includes the following steps: S201: Prepare the materials for the fabrication of the wire; S202: The conductor 101 is stranded in layers; S203: Extruding the insulating layer 102 onto the conductor 101 and cross-linking it; S204: The outer sheath 104 is extruded onto the insulating layer 102 and then cooled and shaped. S205: Inspect and package finished wire products.

[0027] Furthermore, the materials for the wire fabrication are prepared, including conductor 101 material, insulation material, flame-retardant material, and sheath material. The conductor 101 material is made of high-purity oxygen-free copper to ensure excellent conductivity and mechanical strength. The insulation material is a high-performance halogen-free flame-retardant polyolefin material with appropriate amounts of crosslinking agents, antioxidants, and other additives to improve the thermal stability and mechanical strength of the insulation layer 102. The flame-retardant material comprises a nitrogen-phosphorus composite flame retardant, nano-aluminum hydroxide / magnesium hydroxide, zinc borate endothermic agent, and phosphorus-based free radical scavenger, constructing a four-dimensional flame-retardant mechanism. The sheath material is a halogen-free flame-retardant polyolefin sheath material with appropriate amounts of lubricant added to improve processing performance and a heat dissipation channel structure designed. The conductor 101 is layered and stranded. The inner conductor 101 uses a short-pitch, tightly stranded structure, while the outer conductor 101 uses a unidirectional stranded structure. Different diameter copper wires can be rationally configured according to current transmission and flexibility requirements to achieve a balance between bending resistance and conductivity. The insulation layer 102 is extruded onto the conductor 101 and cross-linked. The outer sheath 104 is extruded onto the insulation layer 102 and cooled and shaped. The finished wire is then inspected and packaged. This technology employs a nitrogen-phosphorus composite flame retardant with the synergistic effect of nano-aluminum hydroxide / magnesium hydroxide, combined with zinc borate endothermic agent and phosphorus-based free radical scavenger, to construct a four-dimensional flame retardant mechanism. This significantly improves the flame retardant efficiency of the material, reduces the toxicity of combustion products, and meets the dual requirements of environmental protection and safety in high-end applications. Furthermore, it utilizes a layered stranded conductor 101 integrated structure with heat dissipation and airflow guidance. The layered stranded conductor 101 structure design features a short-pitch, tightly stranded inner layer to ensure flexibility, and a unidirectional stranded outer layer to optimize roundness, enabling the wire to withstand over 10,000 bends. Combined with the spiral airflow channel design of the halogen-free flame-retardant sheath, an air convection channel is formed, reducing the core temperature rise by more than 15°C.

[0028] S206: The mixed insulating material is uniformly wrapped around the conductor 101 through a high-temperature extruder to form the preliminary insulating layer 102; S207: After extrusion, the molecular chains are initially cross-linked through silane grafting technology; S208: The initially cross-linked insulating layer 102 is subjected to electron irradiation treatment.

[0029] Furthermore, the mixed insulating material is uniformly coated onto the conductor 101 using a high-temperature extruder to form a preliminary insulating layer 102. The extrusion temperature and speed are controlled to ensure uniform thickness of the insulating layer 102. During or after extrusion, silane grafting technology is used to achieve preliminary cross-linking of the molecular chains, improving the thermal stability and mechanical strength of the insulating layer 102. The preliminarily cross-linked insulating layer 102 is then subjected to electron irradiation treatment to complete deep curing, ensuring that the thermal elongation of the insulating layer 102 is controlled below 80%, meeting the requirements for use in high-temperature environments.

[0030] S209: The mixed sheathing material is evenly wrapped around the insulation layer 102 through a high-temperature extruder to form a sheathing layer; S210: Cooling and shaping treatment of the extruded sheath layer.

[0031] Furthermore, the mixed sheathing material is evenly coated onto the insulation layer 102 using a high-temperature extruder to form a sheathing layer. During the extrusion process, a specially designed mold forms a heat dissipation channel structure to improve the heat dissipation efficiency of the wire. The extruded sheathing layer is then cooled and shaped to ensure the stability and integrity of the heat dissipation channel structure. The cooling rate and temperature are controlled to prevent deformation or cracking of the sheathing layer.

[0032] S211: Performance testing of finished wires; S212: Packaging of qualified electrical wires.

[0033] Furthermore, the finished wires undergo comprehensive performance testing, including flame retardancy (compliant with GB / T18380.3 standard), low smoke performance (compliant with GB / T17651 standard), low toxicity performance (compliant with GB / T17650 standard), high temperature resistance (long-term operating temperature ≥105℃), and mechanical properties. Wires that pass the tests are then packaged.

[0034] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A high temperature resistant, halogen-free, low smoke, flame retardant stranded flexible cord, characterized in that, It includes a conductor, an insulating layer, a flame-retardant layer, and an outer sheath. The insulating layer is connected to the conductor and located on one side of the conductor. The flame-retardant layer is connected to the insulating layer and located on one side of the insulating layer. The outer sheath is connected to the flame-retardant layer and located on one side of the flame-retardant layer.

2. A process for the preparation of a high temperature resistant, halogen-free, low smoke, flame retardant stranded flexible cord, suitable for use in the high temperature resistant, halogen-free, low smoke, flame retardant stranded flexible cord as claimed in claim 1, characterized in that, Includes the following steps: Prepare the materials for the fabrication of the wire; The conductors are stranded in layers; The insulating layer is extruded onto the conductor and cross-linked. The outer sheath is extruded onto the insulating layer and then cooled and shaped. The finished wires are inspected and packaged.

3. The manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire as described in claim 2, characterized in that, The preparation of materials for wire fabrication includes the following steps: The materials used in the preparation include conductor materials, insulating materials, flame-retardant materials, and sheathing materials.

4. The manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire as described in claim 3, characterized in that, The conductor is stranded in layers, the step of which includes: The conductor adopts a layered stranded structure, with the inner conductor using short-pitch tight stranding and the outer conductor using unidirectional stranding.

5. The manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire as described in claim 4, characterized in that, The steps of extruding an insulating layer onto the conductor and crosslinking it include: The mixed insulating material is evenly wrapped around the conductor using a high-temperature extruder to form the initial insulating layer; After extrusion, the molecular chains are initially cross-linked using silane grafting technology; The initially cross-linked insulating layer is subjected to electron irradiation treatment.

6. The manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire as described in claim 5, characterized in that, The outer sheath is extruded onto the insulating layer and then cooled and shaped. The steps include: The mixed sheath material is evenly wrapped onto the insulation layer through a high-temperature extruder to form a sheath layer; The extruded sheath layer is cooled and shaped.

7. The manufacturing process of the high-temperature resistant, halogen-free, low-smoke, flame-retardant stranded flexible wire as described in claim 6, characterized in that, The process of inspecting and packaging finished wires includes the following steps: Perform performance testing on the finished wires; Wires that pass the inspection are packaged.

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