High flame retardant drip-proof cable

Abstract

The utility model provides a kind of high flame-retardant drip-proof cable, it is related to cable safety technical field, by inside to outside in turn includes conductor, insulating layer, drip-proof barrier layer, flame-retardant reinforcing layer and outer sheath, the drip-proof barrier layer includes mesh metal framework and flame-retardant adhesive, the mesh metal framework's mesh hole diameter is 0.3-0.5mm, the flame-retardant adhesive is wrapped in the mesh metal framework surface, and the coating thickness is 0.8-1.2mm;The flame-retardant reinforcing layer is inlaid with 3-6 expansion flame-retardant strips, which extend along the axial direction of the cable and are evenly distributed in the circumferential direction of the cable;The outer sheath is wrapped outside the flame-retardant reinforcing layer and has a spiral flow guide groove on the surface, which prevents the molten material from dripping. The utility model can more effectively solve the problem of molten dripping during the burning of existing cables by limiting the mesh hole diameter of the mesh metal framework, the thickness of the flame-retardant adhesive, and the number of expansion flame-retardant strips, while ensuring the flame retardancy, insulation, and mechanical properties of the cable.

Description

Technical Field

[0001] This utility model belongs to the field of cable safety technology, and in particular relates to a highly flame-retardant and drip-proof cable. Background Technology

[0002] As a core component for power transmission and signal transmission, the safety and reliability of cables are directly related to the stable operation of the entire power system and the safety of people's lives and property. Especially in densely populated or critical infrastructure locations such as high-rise buildings, subway tunnels, nuclear power plants, and data centers, the fire safety performance of cables is of paramount importance.

[0003] Currently, traditional flame-retardant cables mostly improve their flame-retardant performance by adding flame retardants. These flame retardants exert their flame-retardant effect by decomposing and absorbing heat during combustion, diluting oxygen and water vapor, and can slow the spread of flames to a certain extent. However, this traditional approach has significant limitations. The insulation and sheathing materials of most cables are organic polymers. These polymers can melt, degrade, or even burn under flame. Even with the addition of flame retardants, when the ambient temperature reaches the material's critical temperature, these polymers will still soften and flow, forming high-temperature, flaming molten drips. Because these drips are hot, they can easily ignite the cable trays, equipment, or other combustibles below, causing the fire to spread downwards or horizontally, creating a terrible "secondary disaster" or "fire jump zone."

[0004] In response to this situation, some solutions have attempted to improve the situation by increasing the melting point of the material or adding anti-drip agents, but the actual effects have been limited. Simply relying on material modification not only fails to completely eliminate dripping, but may also reduce the mechanical properties and insulation of the cable. Utility Model Content

[0005] This invention provides a highly flame-retardant and drip-proof cable. By limiting the mesh diameter of the mesh metal skeleton, the thickness of the flame-retardant adhesive, and the number of expanding flame-retardant strips, it can more effectively solve the problem of melting and dripping when existing cables burn, while ensuring the cable's flame retardancy, insulation, and mechanical properties.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a high flame-retardant and drip-proof cable, comprising, from the inside out, a conductor, an insulation layer, a drip-proof barrier layer, a flame-retardant reinforcement layer, and an outer sheath. The drip-proof barrier layer comprises a mesh metal skeleton and a flame-retardant adhesive. The mesh diameter of the mesh metal skeleton is 0.3-0.5 mm, and the flame-retardant adhesive is wrapped around the surface of the mesh metal skeleton with a coating thickness of 0.8-1.2 mm. The flame-retardant reinforcement layer is embedded with 3-6 expanding flame-retardant strips extending along the cable axis and evenly distributed around the cable circumference. The outer sheath wraps around the flame-retardant reinforcement layer and has a spiral guide groove on its surface to prevent concentrated dripping of molten material.

[0007] Furthermore, the conductor is a multi-strand copper wire stranded structure, and the conductor is wrapped with a semi-conductive resistive water tape.

[0008] Furthermore, the insulation layer is made of cross-linked polyethylene material, and nano-montmorillonite flame retardant is uniformly dispersed inside.

[0009] Furthermore, the mesh metal skeleton is a braided structure of aluminum alloy wire.

[0010] Furthermore, the flame-retardant reinforcing layer is made of low-smoke halogen-free polyolefin material.

[0011] Furthermore, the pitch of the spiral guide groove is 10-15mm, and the groove depth is 0.5-0.8mm.

[0012] Based on the above technical solution, the beneficial effects of this utility model are as follows: 1. The composite design of the mesh metal skeleton and flame-retardant adhesive in this utility model is key to achieving high flame-retardant and drip-proof functionality. Setting the mesh diameter of the mesh metal skeleton to 0.3-0.5mm effectively achieves both mechanical support and drip-proof functions. If the aperture is larger than 0.5mm, molten insulating material can easily drip through the holes, failing to block drips. If it is smaller than 0.3mm, the rigidity of the mesh metal skeleton will be increased, reducing the flexibility of the cable and hindering bending and laying. It will also increase material costs and weight. Furthermore, this mesh size provides sufficient surface area for the flame-retardant adhesive, facilitating its embedding and adhesion to form a strong composite. The thickness of the flame-retardant adhesive coating is set at 0.8-1.2mm to effectively ensure its high flame-retardant function. If the thickness is less than 0.8mm, it is difficult to form a sufficiently thick carbonized layer at high temperatures to seal and block flames and oxygen. The mechanical strength is also insufficient, making it easy to break. If it is greater than 1.2mm, it will unnecessarily increase the cable's outer diameter, weight, and cost, and may also reduce the cable's flexibility. At the same time, this thickness can completely cover any small burrs or unevenness that may exist in the metal skeleton, preventing it from contacting the external structure and causing short circuits or affecting electrical performance.

[0013] 2. The design of uniformly embedding 3-6 expandable flame-retardant strips in the flame-retardant reinforcement layer in this utility model further enhances the anti-drip and fireproof effects. Three strips are suitable for smaller diameter cables, forming at least three support points in the circumferential direction. After expansion, they connect to form an effective fire barrier. Four to six strips are suitable for larger diameter cables or cables with higher fire resistance requirements. A larger number of flame-retardant strips allows the expandable material to fill all spaces more quickly and evenly during a fire, avoiding unprotected "dead corners" and achieving more reliable all-round circumferential protection. However, too many strips will also increase costs, reduce cable flexibility, and decrease marginal benefits.

[0014] 3. The spiral guide groove design on the surface of the outer sheath in this utility model can guide the molten material to flow in a dispersed manner, avoiding concentrated dripping that could cause secondary fires, thus further improving the safety of drip prevention. The high oxygen index of the outer sheath itself, in synergy with other structures (nano-flame retardant insulation layer and flame-retardant expansion layer), can enable the overall flame retardant rating of the cable to reach UL94V-0 level, and the amount of smoke generated during combustion is low. Ultimately, the product achieves a balance between flame retardancy, drip prevention, mechanical properties and ease of installation, making it suitable for various complex scenarios. Attached Figure Description

[0015] Figure 1 This is a top view of the cross-section of the present invention.

[0016] The markings in the diagram are: 1. Conductor, 2. Insulation layer, 3. Anti-drip barrier layer, 4. Flame retardant reinforcement layer, 5. Outer sheath. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this utility model. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this utility model can produce, should still fall within the scope of the technical content disclosed in this utility model.

[0019] like Figure 1 As shown, a high flame-retardant and drip-proof cable comprises, from the inside out, a conductor 1, an insulation layer 2, a drip-proof barrier layer 3, a flame-retardant reinforcement layer 4, and an outer sheath 5. The conductor 1 is a multi-strand copper wire stranded structure. The diameter of the conductor 1 can be designed according to the current carrying capacity requirements. The conductor 1 is wrapped with a semi-conductive water-resistant tape to prevent moisture from entering and affecting the conductivity.

[0020] The insulation layer 2 is based on cross-linked polyethylene and contains 5%-8% nano-montmorillonite flame retardant uniformly dispersed inside. Cross-linked polyethylene has excellent insulation and heat resistance, while nano-montmorillonite can improve the thermal stability of the material, slow down the burning rate, and enhance the mechanical strength of the insulation layer.

[0021] The anti-drip barrier layer 3, as the core structure of the cable's anti-drip design, includes a mesh metal skeleton and a flame-retardant adhesive. The mesh metal skeleton is woven from aluminum alloy wire with a mesh diameter of 0.3-0.5 mm, forming a rigid support structure for the anti-drip barrier layer 3. The flame-retardant adhesive is a mixture of epoxy resin and magnesium hydroxide in a 3:1 mass ratio, wrapped around the surface of the mesh metal skeleton with a coating thickness of 0.8-1.2 mm. When the cable burns, the metal skeleton can prevent molten material from dripping. At the same time, the flame-retardant adhesive decomposes upon heating to produce water vapor, which dilutes oxygen and cools the molten material, causing it to solidify within the barrier layer.

[0022] The flame-retardant reinforcement layer 4 uses low-smoke halogen-free polyolefin as its base material, possessing environmentally friendly and low-smoke characteristics. It contains 3-6 intumescent flame-retardant strips, each with a diameter of 2-3 mm. These strips extend along the cable's axial direction and are evenly distributed around the cable's circumference. The intumescent flame-retardant strip material comprises ammonium polyphosphate, melamine, and pentaerythritol in a mass ratio of 5:3:2. Upon contact with fire, the intumescent flame-retardant strips rapidly expand, with an expansion ratio of not less than 200%, forming a dense carbon layer that blocks heat transfer to the inner layer. Simultaneously, it works in conjunction with the anti-drip barrier layer to prevent the flow of molten material.

[0023] The outer sheath 5 is made of chlorinated polyvinyl chloride material with added antimony trioxide and zinc borate as synergistic flame retardants. The antimony trioxide content is 5%-7%, the zinc borate content is 3%-5%, and the oxygen index is not less than 38, meeting the UL94V-0 flame retardant requirements. The surface of the outer sheath 5 is provided with a spiral guide groove with a pitch of 10-15mm and a groove depth of 0.5-0.8mm. This structure can guide a small amount of unobstructed molten material to flow slowly along the groove during combustion, avoiding concentrated dripping, and at the same time enhancing the heat dissipation of the outer sheath.

[0024] Example 1 A high flame-retardant and drip-proof cable comprises: conductor 1 made of 19 strands of copper wire, with each strand having a diameter of 0.5 mm; conductor 1 is wrapped with semi-conductive resistive water tape; insulation layer 2 consists of cross-linked polyethylene and 6% nano-montmorillonite by mass, with a thickness of 2 mm; drip-proof barrier layer 3 has aluminum alloy wire with a diameter of 0.1 mm, a mesh diameter of 0.4 mm, and a flame-retardant adhesive thickness of 1 mm; flame-retardant reinforcement layer 4 is a low-smoke halogen-free polyolefin with four embedded intumescent flame-retardant strips, each with a diameter of 2.5 mm; outer sheath 5 is made of chlorinated polyvinyl chloride with added antimony trioxide and zinc borate as synergistic flame retardants, wherein the antimony trioxide content is 6% and the zinc borate content is 4%, with a thickness of 1.5 mm; and a spiral guide groove with a pitch of 12 mm and a groove depth of 0.6 mm. It produces no molten drips during combustion, achieves a flame retardant rating of UL94V-0, and has an insulation resistance of not less than 10 ohms. 14 With a strength of Ω·cm and an elongation at break of 160%, it can meet the requirements of high-safety scenarios.

[0025] Example 2 A highly flame-retardant and drip-proof cable comprises: conductor 1 made of 37 strands of copper wire, with each strand having a diameter of 0.3 mm; conductor 1 is wrapped with semi-conductive resistive water tape; insulation layer 2 consists of cross-linked polyethylene and 5% nano-montmorillonite by mass, with a thickness of 1.8 mm; drip-proof barrier layer 3 has aluminum alloy wire with a diameter of 0.08 mm, a mesh diameter of 0.3 mm, and a flame-retardant adhesive thickness of 0.8 mm; flame-retardant reinforcement layer 4 is a low-smoke halogen-free polyolefin with four embedded intumescent flame-retardant strips, each with a diameter of 2 mm; outer sheath 5 is made of chlorinated polyvinyl chloride with antimony trioxide and zinc borate as synergistic flame retardants, wherein antimony trioxide accounts for 5% and zinc borate accounts for 3%, with a thickness of 1.2 mm; and a spiral guide groove with a pitch of 10 mm and a groove depth of 0.5 mm. It produces no molten drips during combustion, achieves a flame retardant rating of UL94V-0, and has an insulation resistance of not less than 10 ohms. 14 With a strength of Ω•cm and an elongation at break of 155%, it can meet the requirements of high-safety scenarios.

[0026] It should be noted that the above embodiments are only used to illustrate the present utility model, but the present utility model is not limited to the above embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.

Claims

1. A highly flame-retardant and drip-proof cable, characterized in that: From the inside out, it includes a conductor (1), an insulation layer (2), a drip-proof barrier layer (3), a flame-retardant reinforcement layer (4), and an outer sheath (5). The drip-proof barrier layer (3) includes a mesh metal skeleton and a flame-retardant adhesive. The mesh diameter of the mesh metal skeleton is 0.3-0.5 mm. The flame-retardant adhesive is wrapped around the surface of the mesh metal skeleton with a coating thickness of 0.8-1.2 mm. The flame-retardant reinforcement layer (4) is embedded with 3-6 expanding flame-retardant strips that extend along the cable axis and are evenly distributed around the cable circumference. The outer sheath (5) is wrapped around the flame-retardant reinforcement layer and has a spiral guide groove on its surface to prevent molten material from dripping in a concentrated manner.

2. The high flame-retardant and drip-proof cable according to claim 1, characterized in that: The conductor (1) is a multi-strand copper wire stranded structure, and the conductor (1) is wrapped with a semi-conductive resistive water tape.

3. The high flame-retardant and drip-proof cable according to claim 1, characterized in that: The insulation layer (2) is made of cross-linked polyethylene material and contains uniformly dispersed nano-montmorillonite flame retardant.

4. The high flame-retardant and drip-proof cable according to claim 1, characterized in that: The mesh metal skeleton is a braided structure of aluminum alloy wire.

5. The high flame-retardant and drip-proof cable according to claim 1, characterized in that: The flame-retardant reinforcement layer (4) is made of low-smoke halogen-free polyolefin material.

6. The high flame-retardant and drip-proof cable according to claim 1, characterized in that: The spiral guide groove has a pitch of 10-15 mm and a groove depth of 0.5-0.8 mm.

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