Copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheath flame-retardant low-temperature-resistant cable and processing technology

Abstract

The invention discloses a copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheath flame-retardant low-temperature-resistant cable and a processing technology, and relates to the technical field of flame-retardant low-temperature-resistant cables.The flame-retardant low-temperature-resistant cable is sequentially provided with a composite flame-retardant conductor layer, a low-temperature modified insulating layer, an armored structure layer and a sheath functional layer from inside to outside, and the composite flame-retardant conductor layer comprises a copper core conductor; the surface of the copper core conductor is coated with a halogen-free flame-retardant wrapping tape, the halogen-free flame-retardant wrapping tape is prepared by blending a nano magnesium hydroxide and rare earth oxide composite flame retardant and a silane cross-linking agent, the mass ratio of the nano magnesium hydroxide to the rare earth oxide composite flame retardant is 8: 2, the flame retardant proportion of the halogen-free flame-retardant wrapping tape is 35 wt%, and the flame retardant proportion of the silane cross-linking agent is 35 wt%. The low-temperature modified insulating layer is prepared by adding 15 wt% of an ethylene-vinyl acetate copolymer flexibilizer and 10 wt% of a cold-resistant plasticizer dioctyl adipate into a cross-linked polyethylene base material, the glass transition temperature is less than or equal to-55 DEG C, the armored structure layer is double-layer gap type steel tape armoring, and the inner layer of the double-layer gap type steel tape armoring is a galvanized steel tape.

Description

Technical Field

[0001] The invention relates to the technical field of flame-retardant and low-temperature-resistant cables, in particular to a copper-core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame-retardant and low-temperature-resistant cable and a processing technology thereof. Background Art

[0002] The research and development of copper-core, cross-linked polyethylene insulated, steel-tape armored, PVC-sheathed, flame-retardant, and low-temperature-resistant cables stems from the stringent requirements for cable performance in modern industry, energy, construction, and other fields. Its technological development is closely centered around adaptability to extreme environments, safety, and reliability. It utilizes a double-layer galvanized steel tape gap wrapping process to ensure the cable's bending performance while also enhancing its resistance to lateral pressure and impact. The steel tape thickness and overlap ratio must be designed based on mechanical strength requirements. In cold regions, the insulation and sheath materials of traditional cables are prone to cracking due to low-temperature hardening, leading to insulation failure. Low-temperature-resistant cables must maintain flexibility at temperatures of -40°C or even lower to ensure stable mechanical and electrical properties. However, the carbonization height of existing flame-retardant and low-temperature-resistant cables is significantly low.

[0003] The defects of existing flame retardant and low temperature resistant cables are: 1. Patent document CN104672731A discloses a low-temperature and oil-resistant halogen-free flame-retardant cable material, which "comprises the following raw materials: 100 parts of ethylene vinyl acetate, 10-15 parts of an ethylene resin having polar groups, 29-40 parts of a polyether polyurethane resin, 140-170 parts of an aluminum hydrate, 15-55 parts of a magnesium hydrate, 3-5 parts of an antioxidant, 10-15 parts of a plasticizer, and 4-5 parts of a cross-linking agent. The cable material of the present invention does not contain halogens and does not release toxic gases harmful to the human body when burned in a ship. The cable material also meets the flame retardancy requirements of general ship cables, and the polymer resin material can still maintain elasticity at low temperatures of -40°C. It also meets the oil resistance requirements of standard IEC 60092-359 for general ship cables and the oil resistance requirements of standard NEK606 for offshore structures." However, the carbonization height of existing flame-retardant and low-temperature resistant cables is significantly low; 2. Patent document CN103483708B discloses a low-temperature flame-retardant rubber cable sheath material, which "comprises the following steps: mixing 30% chlorinated polyethylene and 10% EPDM rubber in an internal mixer for 3 to 4 minutes; adding 0.5% lead monoxide, 290% calcium carbonate, 0.5% N-isopropylbenzene-N'-phenyl-p-phenylenediamine, 3% antimony trioxide, 0.1% magnesium oxide, 5% paraffin oil, and 5% chlorinated paraffin in the internal mixer; finally adding 1% paraffin, 5% high-wear-resistant carbon black, 3% precipitated silica, and talc in the internal mixer. 5% and 0.1% γ-aminopropyltriethoxysilane. The mixed rubber material is discharged from the internal mixer when the temperature reaches 90°C-100°C. The calendered mixed rubber material is placed in the internal mixer for mixing. When the mixing temperature reaches 90°C-120°C, 1.5% dicumyl peroxide and 1.3% triallyl isocyanurate are added. The present invention can pass the -40°C low-temperature embrittlement test, has excellent low-temperature resistance, an oxygen index greater than 32, and good flame retardancy. However, existing flame-retardant and low-temperature-resistant cables have low -50°C elongation retention. Summary of the Invention

[0004] The purpose of the present invention is to provide a copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame retardant and low-temperature resistant cable and a processing technology to solve the technical problem of the flame retardant and low-temperature resistant cable proposed in the above background technology that the carbonization height of the flame retardant and low-temperature resistant cable is obviously not high.

[0005] To achieve the above object, the present invention provides the following technical solution: a copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame-retardant and low-temperature resistant cable, which comprises a composite flame-retardant conductor layer, a low-temperature modified insulation layer, an armor structure layer, and a sheath functional layer arranged in sequence from the inside to the outside; The composite flame-retardant conductor layer includes a copper core conductor coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and a rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of the nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant in the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer is made of a cross-linked polyethylene base material with 15wt% of ethylene-vinyl acetate copolymer toughening agent and 10wt% of dioctyl adipate, a cold-resistant plasticizer, added. The glass transition temperature is ≤-55°C. The armor structure layer is a double-layer gap type steel belt armor, the inner layer of the double-layer gap type steel belt armor is galvanized steel belt, the thickness of the galvanized steel belt is 0.15mm, the gap ratio of the galvanized steel belt is 30%, and the outer layer of the double-layer gap type steel belt is stainless steel belt, the thickness of the stainless steel belt is 0.1mm, and the corrugation ratio of the stainless steel belt is 45°; The sheath functional layer is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant comprises ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2.

[0006] Preferably, the rare earth oxide of the composite flame-retardant conductor layer is a cerium oxide and lanthanum oxide complex, the mass ratio of the rare earth oxide is 7:3, the particle size of the rare earth oxide is the cerium oxide and lanthanum oxide complex is ≤200nm, and the rare earth oxygen is preferably the cerium oxide and lanthanum oxide complex with an oxygen inclusion index ≥38%.

[0007] Preferably, the dielectric strength of the low-temperature modified insulating layer is ≥25 kV / mm.

[0008] Preferably, the double-layer gap type steel belt armor of the armor structure layer adopts a cross wrapping with a helix angle of 60°, the wrapping coverage rate is 50±5% for the inner layer and 30±5% for the outer layer, and the bending radius of the double-layer gap type steel belt armor is ≤15 times the outer diameter of the cable.

[0009] Preferably, a nano-radiation heat dissipation coating is provided on the outer surface of the sheath functional layer. The nano-radiation heat dissipation coating is composed of a titanium dioxide and silicon carbide composite. The mass ratio of titanium dioxide to silicon carbide is 4:1. The thermal emissivity of the nano-radiation heat dissipation coating is ≥0.92.

[0010] Preferably, step 1: flame retardant treatment of the conductor: The copper core conductor is preheated to 80°C and coated with a molten halogen-free flame-retardant tape by an extrusion coating machine. The coating thickness of the molten halogen-free flame-retardant tape is 0.3 mm, and the cooling rate of the molten halogen-free flame-retardant tape is 5°C / min. Step 2: Co-extrusion of insulation layer: A double-layer co-extrusion die is used, with the inner layer extruding a cross-linked polyethylene substrate at an extrusion temperature of 185°C, and the outer layer extruding an EVA / DOA mixture at a temperature of 175°C. After cooling and shaping, the mixture is irradiated and cross-linked at a dose of 120kGy. Step 3 Armor layer pressing: After plasma cleaning, the steel strip is wrapped using a servo-controlled armoring machine with tension control of 18N / mm² for the inner layer and 12N / mm² for the outer layer; Step 4: Dynamic vulcanization of the jacket: Polyvinyl chloride, ammonium polyphosphate, melamine and pentaerythritol were mixed in a torque rheometer at a mixing temperature of 160°C and a mixing time of 8 minutes. After mixing, the sheath was coated by a screw extruder at an extruder temperature of 170°C and a dynamic vulcanization pressure of 2.5 MPa.

[0011] Preferably, the radiation cross-linking in step 2 uses an electron beam scanning device with a scanning frequency of 200 Hz and a beam current intensity of 15 mA to ensure that the volume resistivity of the insulating layer is ≥1×10 15 Ω·m.

[0012] Preferably, a coupling agent γ-aminopropyltriethoxysilane is added during the mixing process in step 4, with the coupling agent accounting for 1.5 wt % to enhance the interfacial bonding strength between the flame retardant and the substrate.

[0013] Preferably, after the armor layer is pressed in step 3, the armor gap ratio is detected online and wrapped using an X-ray real-time imaging system with an accuracy of ±0.05mm.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention comprises a composite flame-retardant conductor layer 1 including a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and a rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of the nano-magnesium hydroxide and the rare earth oxide composite flame retardant is 8:2. The flame retardant in the halogen-free flame-retardant tape accounts for 35wt%. The carbonization height of the flame-retardant and low-temperature resistant cable of the present invention is significantly improved. 2. The present invention is made by installing a low-temperature modified insulation layer 2, which is a cross-linked polyethylene base material with 15wt% of ethylene-vinyl acetate copolymer toughening agent and 10wt% of cold-resistant plasticizer dioctyl adipate. The glass transition temperature is -55°C. The retention rate of the elongation at break at -50°C of the flame-retardant and low-temperature resistant cable of the present invention is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a front view structural schematic diagram of the present invention; Figure 2 This is a representation of the experimental data of the present invention.

[0016] In the figure: 1. Composite flame-retardant conductor layer; 2. Low-temperature modified insulation layer; 3. Armor structure layer; 4. Sheath functional layer. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0018] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection or an electrical connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components. Those skilled in the art will understand this in light of the specific circumstances.

[0020] Example 1: Please refer to Figure 1 The present invention provides an embodiment of a copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame-retardant and low-temperature resistant cable, which comprises, from the inside to the outside, a composite flame-retardant conductor layer 1, a low-temperature modified insulation layer 2, an armor structure layer 3, and a sheath functional layer 4; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -55°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant comprises ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide composite. The rare earth oxide is a cerium oxide and lanthanum oxide composite in a mass ratio of 7:3. The particle size of the rare earth oxide is a cerium oxide and lanthanum oxide composite of 200 nm. The rare earth oxide is a cerium oxide and lanthanum oxide composite with an oxygen index of ≥38%, low The dielectric strength of the temperature-modified insulation layer 2 is ≥25kV / mm, the double-layer gap steel tape armor of the armor structure layer 3 adopts a cross-wrap with a helix angle of 60°, the wrapping coverage rate of the inner layer is 50±5% and the outer layer is 30±5%, the bending radius of the double-layer gap steel tape armor is ≤15 times the outer diameter of the cable, and the outer surface of the sheath functional layer 4 is provided with a nano-radiation heat dissipation coating, which is composed of a titanium dioxide and silicon carbide composite, with a mass ratio of titanium dioxide to silicon carbide of 4:1, and the thermal emissivity of the nano-radiation heat dissipation coating is ≥0.92.

[0021] Processing technology of copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, step 1 conductor flame retardant treatment: The copper core conductor is preheated to 80°C and coated with a molten halogen-free flame-retardant tape by an extrusion coating machine. The coating thickness of the molten halogen-free flame-retardant tape is 0.3 mm, and the cooling rate of the molten halogen-free flame-retardant tape is 5°C / min. Step 2: Co-extrusion of insulation layer: A double-layer co-extrusion die is used, with the inner layer extruding a cross-linked polyethylene substrate at an extrusion temperature of 185°C, and the outer layer extruding an EVA / DOA mixture at a temperature of 175°C. After cooling and shaping, the mixture is irradiated and cross-linked at a dose of 120kGy. Step 3 Armor layer pressing: After plasma cleaning, the steel strip is wrapped using a servo-controlled armoring machine with tension control of 18N / mm² for the inner layer and 12N / mm² for the outer layer; Step 4: Dynamic vulcanization of the jacket: Polyvinyl chloride, ammonium polyphosphate, melamine and pentaerythritol were mixed in a torque rheometer at a mixing temperature of 160°C for 8 min. After mixing, the sheath was coated by a screw extruder at a temperature of 170°C and a dynamic vulcanization pressure of 2.5 MPa. In step 2, irradiation crosslinking was performed using an electron beam scanning device with a scanning frequency of 200 Hz and a beam current intensity of 15 mA to ensure that the volume resistivity of the insulating layer was ≥1×10 15Ω·m, in step 4, a coupling agent γ-aminopropyltriethoxysilane is added during the mixing process, with a coupling agent proportion of 1.5wt% to improve the interfacial bonding strength between the flame retardant and the substrate. In step 3, after the armor layer is pressed, the armor gap ratio is detected online, and an X-ray real-time imaging system is used for wrapping, with an accuracy of ±0.05mm.

[0022] Example 2: Please refer to Figure 1 The present invention provides an embodiment of a copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame-retardant and low-temperature resistant cable, which comprises, from the inside to the outside, a composite flame-retardant conductor layer 1, a low-temperature modified insulation layer 2, an armor structure layer 3, and a sheath functional layer 4; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -60°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant comprises ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide complex. The rare earth oxide is a cerium oxide and lanthanum oxide complex in a mass ratio of 7:3. The particle size of the rare earth oxide is a cerium oxide and lanthanum oxide complex of 210 nm. The rare earth oxide is a cerium oxide and lanthanum oxide complex with an oxygen index of ≥38%, low The dielectric strength of the temperature-modified insulation layer 2 is ≥25kV / mm, the double-layer gap steel tape armor of the armor structure layer 3 adopts a cross-wrap with a helix angle of 60°, the wrapping coverage rate of the inner layer is 50±5% and the outer layer is 30±5%, the bending radius of the double-layer gap steel tape armor is ≤15 times the outer diameter of the cable, and the outer surface of the sheath functional layer 4 is provided with a nano-radiation heat dissipation coating, which is composed of a titanium dioxide and silicon carbide composite, with a mass ratio of titanium dioxide to silicon carbide of 4:1, and the thermal emissivity of the nano-radiation heat dissipation coating is ≥0.92.

[0023] Processing technology of copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, step 1 conductor flame retardant treatment: The copper core conductor is preheated to 80°C and coated with a molten halogen-free flame-retardant tape by an extrusion coating machine. The coating thickness of the molten halogen-free flame-retardant tape is 0.3 mm, and the cooling rate of the molten halogen-free flame-retardant tape is 5°C / min. Step 2: Co-extrusion of insulation layer: A double-layer co-extrusion die is used, with the inner layer extruding a cross-linked polyethylene substrate at an extrusion temperature of 185°C, and the outer layer extruding an EVA / DOA mixture at a temperature of 175°C. After cooling and shaping, the mixture is irradiated and cross-linked at a dose of 120kGy. Step 3 Armor layer pressing: After plasma cleaning, the steel strip is wrapped using a servo-controlled armoring machine with tension control of 18N / mm² for the inner layer and 12N / mm² for the outer layer; Step 4: Dynamic vulcanization of the jacket: Polyvinyl chloride, ammonium polyphosphate, melamine and pentaerythritol were mixed in a torque rheometer at a mixing temperature of 160°C for 8 min. After mixing, the sheath was coated by a screw extruder at a temperature of 170°C and a dynamic vulcanization pressure of 2.5 MPa. In step 2, irradiation crosslinking was performed using an electron beam scanning device with a scanning frequency of 200 Hz and a beam current intensity of 15 mA to ensure that the volume resistivity of the insulating layer was ≥1×10 15 Ω·m, in step 4, a coupling agent γ-aminopropyltriethoxysilane is added during the mixing process, with a coupling agent proportion of 1.5wt% to improve the interfacial bonding strength between the flame retardant and the substrate. In step 3, after the armor layer is pressed, the armor gap ratio is detected online, and an X-ray real-time imaging system is used for wrapping, with an accuracy of ±0.05mm.

[0024] Example 3: Please refer to Figure 1 The present invention provides an embodiment of a copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame-retardant and low-temperature resistant cable, which comprises, from the inside to the outside, a composite flame-retardant conductor layer 1, a low-temperature modified insulation layer 2, an armor structure layer 3, and a sheath functional layer 4; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -62°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant comprises ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide composite. The rare earth oxide is a cerium oxide and lanthanum oxide composite in a mass ratio of 7:3. The particle size of the rare earth oxide is a cerium oxide and lanthanum oxide composite of 215 nm. The rare earth oxide is a cerium oxide and lanthanum oxide composite with an oxygen index of ≥38%, low The dielectric strength of the temperature-modified insulation layer 2 is ≥25kV / mm, the double-layer gap steel tape armor of the armor structure layer 3 adopts a cross-wrap with a helix angle of 60°, the wrapping coverage rate of the inner layer is 50±5% and the outer layer is 30±5%, the bending radius of the double-layer gap steel tape armor is ≤15 times the outer diameter of the cable, and the outer surface of the sheath functional layer 4 is provided with a nano-radiation heat dissipation coating, which is composed of a titanium dioxide and silicon carbide composite, with a mass ratio of titanium dioxide to silicon carbide of 4:1, and the thermal emissivity of the nano-radiation heat dissipation coating is ≥0.92.

[0025] Processing technology of copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, step 1 conductor flame retardant treatment: The copper core conductor is preheated to 80°C and coated with a molten halogen-free flame-retardant tape by an extrusion coating machine. The coating thickness of the molten halogen-free flame-retardant tape is 0.3 mm, and the cooling rate of the molten halogen-free flame-retardant tape is 5°C / min. Step 2: Co-extrusion of insulation layer: A double-layer co-extrusion die is used, with the inner layer extruding a cross-linked polyethylene substrate at an extrusion temperature of 185°C, and the outer layer extruding an EVA / DOA mixture at a temperature of 175°C. After cooling and shaping, the mixture is irradiated and cross-linked at a dose of 120kGy. Step 3 Armor layer pressing: After plasma cleaning, the steel strip is wrapped using a servo-controlled armoring machine with tension control of 18N / mm² for the inner layer and 12N / mm² for the outer layer; Step 4: Dynamic vulcanization of the jacket: Polyvinyl chloride, ammonium polyphosphate, melamine and pentaerythritol were mixed in a torque rheometer at a mixing temperature of 160°C for 8 min. After mixing, the sheath was coated by a screw extruder at a temperature of 170°C and a dynamic vulcanization pressure of 2.5 MPa. In step 2, irradiation crosslinking was performed using an electron beam scanning device with a scanning frequency of 200 Hz and a beam current intensity of 15 mA to ensure that the volume resistivity of the insulating layer was ≥1×10 15 Ω·m, in step 4, a coupling agent γ-aminopropyltriethoxysilane is added during the mixing process, with a coupling agent proportion of 1.5wt% to improve the interfacial bonding strength between the flame retardant and the substrate. In step 3, after the armor layer is pressed, the armor gap ratio is detected online, and an X-ray real-time imaging system is used for wrapping, with an accuracy of ±0.05mm.

[0026] Example 4: Please refer to Figure 1 The present invention provides an embodiment of a copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame-retardant and low-temperature resistant cable, which comprises, from the inside to the outside, a composite flame-retardant conductor layer 1, a low-temperature modified insulation layer 2, an armor structure layer 3, and a sheath functional layer 4; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -65°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant comprises ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide complex. The rare earth oxide is a cerium oxide and lanthanum oxide complex in a mass ratio of 7:3. The particle size of the rare earth oxide is a cerium oxide and lanthanum oxide complex of 220 nm. The rare earth oxide is a cerium oxide and lanthanum oxide complex with an oxygen index of ≥38%, low The dielectric strength of the temperature-modified insulation layer 2 is ≥25kV / mm, the double-layer gap steel tape armor of the armor structure layer 3 adopts a cross-wrap with a helix angle of 60°, the wrapping coverage rate of the inner layer is 50±5% and the outer layer is 30±5%, the bending radius of the double-layer gap steel tape armor is ≤15 times the outer diameter of the cable, and the outer surface of the sheath functional layer 4 is provided with a nano-radiation heat dissipation coating, which is composed of a titanium dioxide and silicon carbide composite, with a mass ratio of titanium dioxide to silicon carbide of 4:1, and the thermal emissivity of the nano-radiation heat dissipation coating is ≥0.92.

[0027] Processing technology of copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, step 1 conductor flame retardant treatment: The copper core conductor is preheated to 80°C and coated with a molten halogen-free flame-retardant tape by an extrusion coating machine. The coating thickness of the molten halogen-free flame-retardant tape is 0.3 mm, and the cooling rate of the molten halogen-free flame-retardant tape is 5°C / min. Step 2: Co-extrusion of insulation layer: A double-layer co-extrusion die is used, with the inner layer extruding a cross-linked polyethylene substrate at an extrusion temperature of 185°C, and the outer layer extruding an EVA / DOA mixture at a temperature of 175°C. After cooling and shaping, the mixture is irradiated and cross-linked at a dose of 120kGy. Step 3 Armor layer pressing: After plasma cleaning, the steel strip is wrapped using a servo-controlled armoring machine with tension control of 18N / mm² for the inner layer and 12N / mm² for the outer layer; Step 4: Dynamic vulcanization of the jacket: Polyvinyl chloride, ammonium polyphosphate, melamine and pentaerythritol were mixed in a torque rheometer at a mixing temperature of 160°C for 8 min. After mixing, the sheath was coated by a screw extruder at a temperature of 170°C and a dynamic vulcanization pressure of 2.5 MPa. In step 2, irradiation crosslinking was performed using an electron beam scanning device with a scanning frequency of 200 Hz and a beam current intensity of 15 mA to ensure that the volume resistivity of the insulating layer was ≥1×10 15Ω·m, in step 4, a coupling agent γ-aminopropyltriethoxysilane is added during the mixing process, with a coupling agent proportion of 1.5wt% to improve the interfacial bonding strength between the flame retardant and the substrate. In step 3, after the armor layer is pressed, the armor gap ratio is detected online, and an X-ray real-time imaging system is used for wrapping, with an accuracy of ±0.05mm.

[0028] Comparative experiment: The difference between Comparative Example 1 and Example 1 is that; Copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, which is arranged from the inside to the outside in the order of composite flame retardant conductor layer 1, low temperature modified insulation layer 2, armor structure layer 3, and sheath functional layer 4; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -55°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant contains ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide complex. The rare earth oxide is a cerium oxide and lanthanum oxide complex in a mass ratio of 7:3. The particle size of the rare earth oxide is the cerium oxide and lanthanum oxide complex is 200 nm, and the rare earth oxide is the cerium oxide and lanthanum oxide complex. The oxygen inclusion index of the rare earth oxide is ≥38%.

[0029] The difference between Comparative Example 1 and Example 2 is that; Copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, which is arranged from the inside to the outside in the order of composite flame retardant conductor layer 1, low temperature modified insulation layer 2, armor structure layer 3, and sheath functional layer 4; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -60°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant contains ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide complex. The rare earth oxide is a cerium oxide and lanthanum oxide complex in a mass ratio of 7:3. The particle size of the rare earth oxide is the cerium oxide and lanthanum oxide complex is 210 nm, and the rare earth oxide is the cerium oxide and lanthanum oxide complex. The oxygen inclusion index of the rare earth oxide is ≥38%.

[0030] The difference between Comparative Example 1 and Example 3 is that; Copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, which is arranged from the inside to the outside in the order of composite flame retardant conductor layer 1, low temperature modified insulation layer 2, armor structure layer 3, and sheath functional layer 4; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -62°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant contains ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide complex. The rare earth oxide is a cerium oxide and lanthanum oxide complex in a mass ratio of 7:3. The particle size of the rare earth oxide is the cerium oxide and lanthanum oxide complex is 215 nm, and the rare earth oxide is the cerium oxide and lanthanum oxide complex. The oxygen inclusion index of the rare earth oxide is ≥38%.

[0031] The difference between Comparative Example 1 and Example 4 is that; The composite flame-retardant conductor layer 1 includes a copper core conductor, the surface of which is coated with a halogen-free flame-retardant tape. The halogen-free flame-retardant tape is made by blending nano-magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinker. The mass ratio of nano-magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame-retardant tape accounts for 35wt%; The low-temperature modified insulation layer 2 is made of a cross-linked polyethylene base material with 15 wt% of ethylene-vinyl acetate copolymer toughening agent and 10 wt% of dioctyl adipate, a cold-resistant plasticizer, added thereto, and has a glass transition temperature of -65°C. Armor structure layer 3 is a double-layer interstitial steel belt armor, the inner layer of the double-layer interstitial steel belt armor is a galvanized steel belt with a thickness of 0.15mm and a gap ratio of 30%. The outer layer of the double-layer interstitial steel belt is a stainless steel belt with a thickness of 0.1mm and a corrugation ratio of 45°. The sheath functional layer 4 is a composite intumescent flame retardant in a polyvinyl chloride sheath. The composite intumescent flame retardant contains ammonium polyphosphate, melamine, and pentaerythritol. The composite intumescent flame retardant is compounded in a mass ratio of 5:3:2. The rare earth oxide of the composite flame retardant conductor layer 1 is a cerium oxide and lanthanum oxide complex. The rare earth oxide is a cerium oxide and lanthanum oxide complex in a mass ratio of 7:3. The particle size of the rare earth oxide is the cerium oxide and lanthanum oxide complex is 220 nm, and the rare earth oxide is the cerium oxide and lanthanum oxide complex. The oxygen inclusion index of the rare earth oxide is ≥38%.

[0032] The flame-retardant and low-temperature-resistant cables of Examples 1, 2, 3, 4, and 5 of the present invention and a conventional flame-retardant and low-temperature-resistant cable (Comparative Example 1) were subjected to tests on carbonization height and -50°C elongation retention, and their values ​​were calculated and statistically analyzed. The carbonization height bundle combustion test was conducted according to GB / T 18380.3, and the results are shown in Table 1.

[0033] From the data in Table 1, it can be seen that the carbonization heights of the flame-retardant and low-temperature resistant cables in Examples 1, 2, 3, 4 and 5 of the present invention are 1.2m, 1.5m, 1.6m and 1.4m, respectively, which are significantly higher than the carbonization height of the flame-retardant and low-temperature resistant cable in Comparative Example 1. This indicates that the carbonization height of the flame-retardant and low-temperature resistant cable of the present invention is significantly improved.

[0034] From the data in Table 1, it can be seen that the -50°C elongation retention rates of the flame-retardant and low-temperature resistant cables of Examples 1, 2, 3, 4 and 5 of the present invention are 92%, 93%, 94% and 93% respectively, which are significantly higher than the -50°C elongation retention rate of the flame-retardant and low-temperature resistant cable in Comparative Example 1. Therefore, it is shown that the -50°C elongation retention rate of the flame-retardant and low-temperature resistant cable of the present invention is significantly improved.

[0035] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. Copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable, characterized by include: A composite flame-retardant conductor layer (1), a low-temperature modified insulation layer (2), an armor structure layer (3), and a sheath functional layer (4) are sequentially arranged from the inside to the outside; The composite flame retardant conductor layer (1) comprises a copper core conductor, the surface of the copper core conductor is coated with a halogen-free flame retardant tape, the halogen-free flame retardant tape is made by mixing nano magnesium hydroxide and rare earth oxide composite flame retardant with a silane crosslinking agent, the mass ratio of the nano magnesium hydroxide and rare earth oxide composite flame retardant is 8:2, and the flame retardant of the halogen-free flame retardant tape accounts for 35wt%; The low-temperature modified insulating layer (2) is made of a cross-linked polyethylene base material with 15 wt% of an ethylene-vinyl acetate copolymer toughening agent and 10 wt% of a cold-resistant plasticizer, dioctyl adipate, and has a glass transition temperature of ≤-55°C. The armor structure layer (3) is a double-layer gap type steel belt armor, the inner layer of the double-layer gap type steel belt armor is a galvanized steel belt, the thickness of the galvanized steel belt is 0.15 mm, the gap ratio of the galvanized steel belt is 30%, and the outer layer of the double-layer gap type steel belt is a stainless steel belt, the thickness of the stainless steel belt is 0.1 mm, and the corrugation ratio of the stainless steel belt is 45°; The sheath functional layer (4) is a composite intumescent flame retardant in a polyvinyl chloride sheath, wherein the composite intumescent flame retardant comprises ammonium polyphosphate, melamine, and pentaerythritol, and the composite intumescent flame retardant is compounded in a mass ratio of 5:3:

2.

2. The copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable according to claim 1, characterized in that: The rare earth oxide of the composite flame-retardant conductor layer (1) is a cerium oxide and lanthanum oxide composite, the mass ratio of the rare earth oxide to the cerium oxide and lanthanum oxide composite is 7:3, the particle size of the rare earth oxide to the cerium oxide and lanthanum oxide composite is ≤200nm, and the oxygen inclusion index of the rare earth oxide to the cerium oxide and lanthanum oxide composite is ≥38%.

3. The copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable according to claim 1, characterized in that: The dielectric strength of the low-temperature modified insulating layer (2) is ≥25 kV / mm.

4. The copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable according to claim 1, characterized in that: The double-layer gap-type steel belt armor of the armor structure layer (3) adopts a cross-wrap method with a helical angle of 60°, and the wrapping coverage rate is 50±5% for the inner layer and 30±5% for the outer layer. The bending radius of the double-layer gap-type steel belt armor is ≤15 times the outer diameter of the cable.

5. The copper core cross-linked polyethylene insulated steel tape armored PVC sheathed flame retardant and low temperature resistant cable according to claim 1, characterized in that: The outer surface of the sheath functional layer (4) is provided with a nano-radiation heat dissipation coating, the nano-radiation heat dissipation coating is composed of a titanium dioxide and silicon carbide composite, the mass ratio of titanium dioxide to silicon carbide is 4:1, and the thermal emissivity of the nano-radiation heat dissipation coating is ≥0.

92.

6. A process for producing a copper core cross-linked polyethylene insulated, steel tape armored, PVC sheathed, flame-retardant, and low-temperature-resistant cable, applicable to the copper core cross-linked polyethylene insulated, steel tape armored, PVC sheathed, flame-retardant, and low-temperature-resistant cable according to any one of claims 1 to 5, characterized in that: Step 1 Conductor flame retardant treatment: The copper core conductor is preheated to 80°C and coated with a molten halogen-free flame-retardant tape by an extrusion coating machine. The coating thickness of the molten halogen-free flame-retardant tape is 0.3 mm, and the cooling rate of the molten halogen-free flame-retardant tape is 5°C / min. Step 2: Co-extrusion of insulation layer: A double-layer co-extrusion die is used, with the inner layer extruding a cross-linked polyethylene substrate at an extrusion temperature of 185°C, and the outer layer extruding an EVA / DOA mixture at a temperature of 175°C. After cooling and shaping, the mixture is irradiated and cross-linked at a dose of 120kGy. Step 3 Armor layer pressing: After plasma cleaning, the steel strip is wrapped using a servo-controlled armoring machine with tension control of 18N / mm² for the inner layer and 12N / mm² for the outer layer; Step 4: Dynamic vulcanization of the jacket: Polyvinyl chloride, ammonium polyphosphate, melamine and pentaerythritol were mixed in a torque rheometer at a mixing temperature of 160°C and a mixing time of 8 minutes. After mixing, the sheath was coated by a screw extruder at an extruder temperature of 170°C and a dynamic vulcanization pressure of 2.5 MPa.

7. The processing technology of the copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame retardant and low temperature resistant cable according to claim 6, characterized in that: The radiation cross-linking in step 2 uses an electron beam scanning device with a scanning frequency of 200 Hz and a beam current intensity of 15 mA to ensure that the volume resistivity of the insulating layer is ≥1×10 15 Ω·m.

8. The processing technology of the copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame retardant and low temperature resistant cable according to claim 6, characterized in that: In the mixing process of step 4, a coupling agent γ-aminopropyltriethoxysilane is added, and the coupling agent accounts for 1.5wt% to improve the interfacial bonding strength between the flame retardant and the substrate.

9. The processing technology of the copper core cross-linked polyethylene insulated steel tape armored polyvinyl chloride sheathed flame retardant and low temperature resistant cable according to claim 6, characterized in that: After the armor layer is pressed in step 3, the armor gap ratio is detected online and wrapped using an X-ray real-time imaging system with an accuracy of ±0.05mm.

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