Long-life low-smoke halogen-free flame-retardant cable
By employing a double-layer composite structure of annealed copper conductor and irradiated cross-linked insulation material, combined with long-life nuclear power plant grade materials and metal hydrate flame retardants, the problems of short cable life, insufficient flame retardant performance, and release of toxic gases have been solved, achieving high mechanical performance, low loss, and a safe fire environment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YUANCHENG CABLE CO LTD
- Filing Date
- 2026-03-12
- Publication Date
- 2026-05-12
AI Technical Summary
Existing cables have a short service life, poor aging resistance, insufficient flame retardancy, and release toxic halogen acid gases in fires, resulting in high maintenance costs.
It adopts annealed copper conductors and irradiated cross-linked insulation materials to form a double-layer composite structure with an inner layer of electrical insulation and an outer layer of flame retardant. It uses cross-linked insulation materials of nuclear power plant nuclear grade cables with long life and adds metal hydrate flame retardants. It is made by double-layer co-extrusion insulation and irradiation cross-linking technology.
Extend cable life to 80 years, reduce power loss, prevent the release of toxic gases, improve mechanical and electrical performance, and ensure visibility and safety in case of fire.
Smart Images
Figure CN122025263A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of wire and cable technology, specifically relating to a long-life, low-smoke, halogen-free flame-retardant cable. Background Technology
[0002] With the continuous upgrading of my country's infrastructure construction, especially the increasing requirements for cable safety and durability in high-rise buildings, rail transit, and nuclear power plants, cable service life has become one of the important indicators for measuring its performance. In 2014, the Ministry of Housing and Urban-Rural Development issued new regulations requiring that the design life of building cables be no less than 70 years, which promoted the research and development of long-life cables in the industry.
[0003] However, traditional cables are typically designed for a lifespan of 20 to 30 years and have the following problems:
[0004] 1. Poor aging resistance: During long-term operation, the insulation material is prone to aging and becoming brittle, leading to a decline in electrical performance;
[0005] 2. Insufficient flame retardant properties: Ordinary PVC and other materials release large amounts of toxic halogen acid gas during a fire, hindering the evacuation of personnel;
[0006] 3. High maintenance costs: The short lifespan of the cables necessitates frequent replacements, increasing the long-term operating costs of the project. Summary of the Invention
[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a long-life, low-smoke, halogen-free flame-retardant cable.
[0008] The technical solution adopted to solve the above technical problems is: a long-life low-smoke halogen-free flame-retardant cable, including an annealed copper conductor, the outer layer of which is covered with an irradiated cross-linked insulation material, and the outer layer of which is covered with an irradiated cross-linked low-smoke halogen-free insulation material.
[0009] The irradiated cross-linked insulating material and the irradiated cross-linked low-smoke halogen-free insulating material are made by double-layer co-extrusion insulation and irradiation cross-linking technology, forming a double-layer composite structure with electrical insulation properties in the inner layer and flame retardant properties in the outer layer.
[0010] Furthermore, the annealed copper conductor is made of oxygen-free copper with a purity of 99.9% or higher.
[0011] The above technical solution has extremely low resistance and high conductivity, which can effectively reduce power loss during transmission (energy saving) and prevent overheating caused by excessive resistance. It also has high tensile strength and effectively resists mechanical fatigue.
[0012] Furthermore, the annealed copper conductor adopts a structure of multiple fine copper wires stranded together, with a stranding diameter ratio of 10 to 16 times, and the elongation of a single conductor wire after annealing is not less than 25%.
[0013] Through the above technical solution, multiple fine copper wires are twisted together, which not only ensures the compactness of the conductor structure, but also gives the cable excellent bending performance. This makes it less likely for the conductor to be damaged or the insulation layer to crack due to repeated bending during installation. After annealing, the elongation of the conductor filament is not less than 25%, which makes the conductor material completely softened and the internal processing stress completely eliminated. During long-term operation, even if the cable undergoes cold and heat cycles, the conductor will not puncture the inner insulation layer due to residual stress rebound, thus improving the service life of the cable.
[0014] Furthermore, the irradiated cross-linked insulation material and the irradiated cross-linked low-smoke halogen-free insulation material are cross-linked insulation materials used in long-life nuclear power plant nuclear-grade cables.
[0015] The above technical solution uses cross-linked insulation material for nuclear power plant grade cables with long lifespan to enhance the mechanical and physical properties and electrical properties of the wires. The inner layer meets the electrical insulation performance requirements, the outer layer has flame retardant properties, and both the inner and outer layers meet the long life requirements.
[0016] Furthermore, the irradiated cross-linked low-smoke halogen-free insulating material contains metal hydrate flame retardants.
[0017] Through the above technical solution, the metal hydrate added to the outer layer undergoes endothermic decomposition at high temperature, releasing water of crystallization. In the process, it absorbs heat, dilutes oxygen, and forms a dense carbonized layer, which isolates oxygen and heat transfer. At the same time, since the flame retardant mechanism relies entirely on chemical dehydration and does not involve the participation of halogens, it does not release toxic halogen acid gases during combustion, and the smoke concentration is extremely low, providing valuable visibility and a low-toxicity environment for fire escape.
[0018] The beneficial effects of this invention are as follows:
[0019] (1) The annealed copper conductor has extremely low resistance and high conductivity, which can effectively reduce the loss of power during transmission (energy saving) and prevent heat generation due to excessive resistance. It also has high tensile strength and effectively resists mechanical fatigue.
[0020] (2) By setting up irradiated cross-linked insulation material and irradiated cross-linked low smoke halogen-free insulation material, adopting long-life nuclear power plant nuclear grade cable cross-linked insulation material, double-layer co-extrusion insulation and irradiated cross-linking technology, the mechanical and physical properties and electrical properties of the wire are enhanced. The inner layer meets the electrical insulation performance, the outer layer has flame retardant properties, and both the inner and outer layers meet the long life requirements. The long-term allowable working temperature can be increased from 70℃ to 90℃ or even higher. It has strong overload resistance, high insulation resistance, and strong voltage breakdown resistance, so that its design life can reach 80 years or even longer. It avoids the need for frequent replacement due to wire aging, which would increase costs. At the same time, in the event of a fire, it will not release toxic halogen acid gas and has low smoke production, providing valuable time for personnel evacuation. Attached Figure Description
[0021] Figure 1 This is a cross-sectional view of a long-life, low-smoke, halogen-free flame-retardant cable according to the present invention;
[0022] Figure 2 This is a structural diagram of a long-life, low-smoke, halogen-free flame-retardant cable according to the present invention.
[0023] Reference numerals: 1. Annealed copper conductor; 2. Irradiated cross-linked insulating material; 3. Irradiated cross-linked low-smoke halogen-free insulating material. Detailed Implementation
[0024] 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.
[0025] like Figures 1-2 As shown, a long-life, low-smoke, halogen-free flame-retardant cable of this embodiment includes an annealed copper conductor 1, the outer layer of which is covered with an irradiated cross-linked insulation material 2, and the outer layer of the irradiated cross-linked insulation material 2 is covered with an irradiated cross-linked low-smoke, halogen-free insulation material 3.
[0026] Irradiated cross-linked insulation material 2 and irradiated cross-linked low-smoke halogen-free insulation material 3 are made through double-layer co-extrusion insulation and irradiation cross-linking technology to form a double-layer composite structure with electrical insulation properties in the inner layer and flame retardant properties in the outer layer. Through double-layer co-extrusion technology, the electrical insulation function and flame retardant protection function are designed separately, avoiding the difficulty of a single material to take into account both electrical performance and flame retardancy. The double-layer co-extrusion process makes the inner and outer insulation materials tightly bonded in the molten state, with no gaps or pollution between the layers. This not only improves production efficiency but also avoids the generation of bubbles or impurities between layers, thus extending the cable life.
[0027] Irradiation crosslinking technology transforms polymer molecular chains from a linear structure to a three-dimensional network structure. After the inner layer material is crosslinked, its heat resistance and anti-aging ability are greatly improved; after the outer layer material is crosslinked, its mechanical strength, such as tear resistance and impact resistance, is significantly enhanced. Moreover, when both layers are irradiated at the same time, the good matching of the degree of crosslinking between the two layers avoids the internal stress caused by the difference in the coefficient of thermal expansion during subsequent use, thus ensuring the stability of the composite structure under thermal cycling.
[0028] Annealed copper conductor 1 is made of oxygen-free copper with a purity of over 99.99%. This extremely high purity significantly reduces the obstruction of electron flow by impurities, resulting in excellent conductivity and effectively reducing power loss and conductor heating during cable operation. The annealing treatment eliminates internal stress in the copper, making the conductor more flexible. This not only facilitates cable laying and installation but also reduces the risk of conductor damage caused by bending or vibration. Furthermore, its high tensile strength effectively resists mechanical fatigue in the cable.
[0029] Annealed copper conductor 1 adopts a multi-stranded structure of fine copper wires with a stranding pitch ratio of 10 to 16. After annealing, the elongation of a single conductor wire is not less than 25%. The multi-stranded fine copper wires not only ensure the compactness of the conductor structure but also give the cable excellent bending performance. This makes the cable less prone to conductor damage or insulation layer cracking due to repeated bending during installation. The elongation of a single conductor wire after annealing is not less than 25%, which completely softens the conductor material and eliminates internal processing stress. During long-term operation, even when the cable undergoes thermal cycles, the conductor will not puncture the inner insulation due to residual stress rebound, thus improving the service life of the cable.
[0030] Irradiated cross-linked insulation material 2 and irradiated cross-linked low-smoke halogen-free insulation material 3 are cross-linked insulation materials for long-life nuclear power plant nuclear-grade cables. The cross-linked insulation material for long-life nuclear power plant nuclear-grade cables has excellent heat aging resistance and radiation aging resistance. Combined with "irradiation cross-linking" technology, it greatly improves the heat resistance of the cable, so that its long-term working temperature can be increased from 70℃ to 90℃ or even higher. At the same time, it has high insulation resistance and strong voltage breakdown resistance, which significantly improves the service life of the cable and avoids the trouble and huge cost of replacement due to cable aging.
[0031] The irradiated cross-linked low-smoke halogen-free insulating material contains metal hydrate flame retardants. The outer layer of metal hydrates (such as magnesium hydroxide or aluminum hydroxide) undergoes endothermic decomposition at high temperatures, releasing water of crystallization. During this process, it absorbs heat, dilutes oxygen, and forms a dense carbonized layer, isolating oxygen and heat transfer. Simultaneously, because the flame retardant mechanism relies entirely on chemical dehydration without the involvement of halogens, it does not release toxic halogen acid gases during combustion, and the smoke concentration is extremely low, providing valuable visibility and a low-toxicity environment for fire escape. Through irradiation cross-linking, both the inner and outer layers develop a memory effect, preventing the material from melting and dripping when exposed to the high temperatures of a short circuit or external flames, maintaining structural integrity and effectively isolating the spread of fire.
[0032] The working principle of this embodiment is as follows: Referring to JG / T 441-2014 "Double-layer co-extruded insulated irradiated cross-linked halogen-free low-smoke flame-retardant wires with rated voltage of 450 / 750V and below", the insulated wire was tested and passed a 165℃*168h thermal aging test. This proves that the cable fully meets the 80-year lifespan requirement of the enterprise standard Q320282 DCT 055-2025 "Double-layer co-extruded insulated irradiated cross-linked halogen-free low-smoke flame-retardant wires with rated voltage of 450 / 750V" at a working temperature of 90℃. Furthermore, the elongation at break after aging (250%) is far higher than the standard 190% and the original value of 380%, while the retention rate meets the standard requirement of 50%. According to IEC 60216-1:2013 "Electrical insulation materials—Heat resistance—Part 1: Aging procedures and evaluation of test results", the lifespan of the insulation material is evaluated, and the material lifespan reaches 80 years.
[0033] When the cable is connected to the circuit, the current flows directionally through the annealed copper conductor 1 to complete the transmission of electrical energy or electrical signals. The annealed copper conductor 1 is made of oxygen-free copper with a purity of 99.99% or higher. As a conductor, oxygen-free copper has extremely low resistance and high conductivity, which can effectively reduce power loss during transmission and prevent overheating caused by excessive resistance. It also has high tensile strength and effectively resists mechanical fatigue. The irradiated cross-linked insulation material 2 and the irradiated cross-linked low-smoke halogen-free insulation material 3 can effectively prevent current leakage, force the current to flow strictly along the conductor path, prevent short circuits, and enhance the mechanical and physical properties and electrical properties of the wire. The inner layer meets the electrical insulation performance requirements, the outer layer has flame retardant properties, and both the inner and outer layers meet the long service life requirements.
[0034] When the cable encounters an external flame, the flame retardants (such as metal hydrates) added to the irradiated cross-linked low-smoke halogen-free insulation material 3 begin to function, absorbing heat and releasing water vapor, reducing the surface temperature of the material. The irradiated cross-linked network structure, together with the flame retardant material, forms a dense, expanded carbonized layer on the surface during combustion, isolating oxygen and heat from being transferred inward, preventing the flame from continuing to burn. Since the material formula does not contain halogens, it does not produce a large amount of black smoke and highly toxic corrosive gases during combustion, ensuring the escape line of personnel and the safety of equipment in a fire environment.
[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.
Claims
1. A long-life, low-smoke, halogen-free flame-retardant cable, characterized in that, It includes an annealed copper conductor (1), the outer layer of which is coated with an irradiated cross-linked insulating material (2), and the outer layer of the irradiated cross-linked insulating material (2) is coated with an irradiated cross-linked low-smoke halogen-free insulating material (3). The irradiated cross-linked insulating material (2) and the irradiated cross-linked low-smoke halogen-free insulating material (3) are made by double-layer co-extrusion insulation and irradiation cross-linking technology to form a double-layer composite structure with electrical insulation properties in the inner layer and flame retardant properties in the outer layer.
2. The long-life, low-smoke, halogen-free flame-retardant cable according to claim 1, characterized in that, The annealed copper conductor (1) is made of oxygen-free copper with a purity of 99.99% or higher.
3. According to claim 1, the long-life, low-smoke, halogen-free flame-retardant cable, wherein the annealed copper conductor (1) adopts a multi-stranded structure of fine copper wires with a stranding pitch ratio of 10 to 16 times, and the elongation of the conductor single wire after annealing is not less than 25%.
4. The long-life, low-smoke, halogen-free flame-retardant cable according to claim 1, characterized in that, The irradiated cross-linked insulation material (2) and the irradiated cross-linked low-smoke halogen-free insulation material (3) are cross-linked insulation materials for long-life nuclear power plant nuclear-grade cables.
5. The long-life, low-smoke, halogen-free flame-retardant cable according to claim 1, characterized in that, The irradiated cross-linked low-smoke halogen-free insulating material (3) contains a metal hydrate flame retardant.