CN-121394043-B - Fireproof variable frequency cable

CN121394043BCN 121394043 BCN121394043 BCN 121394043BCN-121394043-B

Abstract

The invention discloses a fireproof variable frequency cable, which belongs to the technical field of cables, and comprises a cable core, an inner protective layer, a shielding layer and an outer protective layer from inside to outside in sequence, wherein the cable core comprises a power wire core and a grounding wire core, the power wire core comprises a conductor, an insulating shielding layer and an ethylene propylene rubber insulating layer from inside to outside, a fireproof filling rope is arranged between the cable core and the inner protective layer, the insulating shielding layer is a high-temperature-resistant crosslinked polyethylene shielding material, the fireproof filling rope is a Kevlar rope with the surface coated with phlogopite powder, and the inner protective layer and the outer protective layer are both high-flame-retardant and wear-resistant polyolefin mixtures. The fireproof variable frequency cable has the advantages of simple structure, better mechanical strength and flexibility, excellent flame retardance, electromagnetic interference resistance, high-temperature stability, wear resistance, corrosion resistance, waterproofness and electrical performance, better electromagnetic shielding performance under severe environments, and prolonged service life.

Inventors

GUO LINXIANG
WANG JINGYANG
LIN WEIQUN
HOU SHAOBIN

Assignees

江西南远电缆有限公司

Dates

Publication Date: 20260512
Application Date: 20251226

Claims (8)

1. The fireproof variable frequency cable comprises a cable core, an inner protective layer, a shielding layer and an outer sheath from inside to outside in sequence, wherein the cable core comprises a power wire core and a grounding wire core; the insulating shielding layer is a high-temperature-resistant crosslinked polyethylene shielding material; the fireproof filling rope is a Kevlar rope coated with phlogopite powder on the surface; The inner protective layer and the outer protective layer are both high-flame-retardance and wear-resistant polyolefin mixtures; The high-temperature-resistant crosslinked polyethylene shielding material is prepared from the following raw materials, by mass, 100 parts of a first polyethylene resin, 8-15 parts of an EMAA ionomer, 5-10 parts of a conductive agent, 1.6-2.8 parts of a first antioxidant, 2.5-3.6 parts of polyethylene wax, 1.2-1.8 parts of a first silane coupling agent and 1.8-3.2 parts of a first irradiation sensitizer; The high flame-retardant wear-resistant polyolefin mixture is prepared from the following raw materials, by mass, 60-80 parts of a second polyethylene resin, 15-30 parts of ethylene propylene diene monomer rubber, 5-10 parts of a thermoplastic polyolefin elastomer, 5-10 parts of maleic anhydride grafted polyethylene, 10-15 parts of a flame retardant, 2.5-3.6 parts of a second antioxidant, 2.2-2.8 parts of a second irradiation sensitizer, 1.8-3.2 parts of a second silane coupling agent and 1.0-2.5 parts of a lubricant; The flame retardant consists of (1.2-2.5) phosphorus-nitrogen flame retardant and silane modified magnesium hydroxide; the preparation method of the phosphorus-nitrogen flame retardant comprises the following steps: s1, adding phosphaphenanthryl aromatic dibasic acid and N, N-dimethylformamide into a reactor, stirring until the phosphaphenanthryl aromatic dibasic acid and the N, N-dimethylformamide are dissolved, then adding a condensing agent and DMAP, stirring for 10-20 min, introducing nitrogen, slowly dropwise adding a hexamethylenediamine solution, ensuring that dropwise adding is completed within 20min, heating to 80-100 ℃, carrying out reflux reaction for 3-5 h, cooling to room temperature, carrying out suction filtration, washing and drying to obtain a phosphorus-nitrogen flame-retardant intermediate; S2, adding the phosphorus-nitrogen flame-retardant intermediate into a proper amount of toluene for full dissolution, then adding octyl trimethoxy silane and an organotin catalyst, stirring uniformly, heating to 110-130 ℃, carrying out reflux reaction for 4-6 hours, cooling to room temperature, carrying out suction filtration, washing and drying to obtain the phosphorus-nitrogen flame retardant.
2. The fire resistant power conversion cable according to claim 1, wherein the ground wire core is composed of an annealed tin-plated copper conductor and an insulating layer wrapped outside the annealed tin-plated copper conductor.
3. The fire resistant variable frequency cable according to claim 1, characterized in that the first polyethylene resin consists of LDPE and LLDPE in a mass ratio (7-9): 1; the conductive agent consists of acetylene black and carbon nano tube/lamellar material compound with the mass ratio of (3-5) being 1.
4. A fire resistant variable frequency cable according to claim 3 wherein the carbon nanotube/layered material composite is an array of carbon nanotubes distributed between the lamellae of layered hydrotalcite.
5. The fireproof variable frequency cable of claim 1, wherein the mass of the phlogopite powder is 10% -15% of the mass of the kevlar rope, and the particle size of the phlogopite powder is 1250-2000 mesh.
6. The fire resistant power conversion cable according to claim 1, wherein the second polyethylene resin consists of HDPE and LLDPE in a mass ratio of (5-7): 1.
7. The fire resistant power conversion cable according to claim 1, wherein, The mol ratio of the phosphaphenanthryl aromatic dibasic acid to hexamethylenediamine in the hexamethylenediamine solution is 1 (1.05-1.2); The mol ratio of the phosphaphenanthryl aromatic dibasic acid to the condensing agent is 1 (1.2-1.5); The mol ratio of the phosphaphenanthryl aromatic dibasic acid to the DMAP is 1 (0.05-0.1); the mass ratio of the phosphorus-nitrogen flame retardant intermediate to the octyl trimethoxysilane is 1 (0.1-0.2); The adding amount of the organotin catalyst is 0.2-0.4% of the total mass of the phosphorus-nitrogen flame retardant intermediate and the octyl trimethoxy silane.
8. The fireproof variable frequency cable of claim 1, wherein the shielding layer is a copper wire braid and a copper plastic composite tape wrapping layer from inside to outside in sequence; the braiding density of the copper wire braiding layer is more than 90%; the copper-plastic composite tape wrapping layer adopts a longitudinal wrapping mode, and the wrapping overlapping rate is 20% -25%.

Description

Fireproof variable frequency cable Technical Field The invention belongs to the technical field of cables, and particularly relates to a waterproof, electromagnetic interference-proof, wear-resistant and fireproof variable-frequency cable and a preparation method thereof. Background The variable frequency cable is mainly used for connecting a variable frequency power supply and a variable frequency motor, and is used for conveying electric energy in power transmission and distribution lines, and the cable is required to have better electromagnetic induction resistance, can resist interference of power supply conduction signals, reduce inductance to a certain extent, play a role in protecting wire cores, and is widely applied to the industrial fields of metallurgy, mines, railways, ships and the like and household appliances. With the increasing demand of medium-high voltage high capacity alternating current motors, the variable frequency voltage level is continuously increased, so that the variable frequency cable is required to have excellent insulativity, high breakdown strength, high volume resistivity and the like, reduce electric leakage and electric energy loss, prevent external interference from affecting cable transmission, and have better electromagnetic shielding performance. The working environment of the variable frequency cable is special, and the variable frequency cable needs to bear high-frequency pulse voltage, high-frequency heat and challenges such as mechanical stress, greasy dirt, humidity and the like possibly existing, so that the variable frequency cable also needs to have good high-low temperature resistance, corrosion resistance, water resistance, weather resistance, wear resistance and the like, so that the performance of the variable frequency cable is prevented from being influenced, the transmission of the variable frequency cable is interrupted, the short circuit of an electric appliance is caused, the electric appliance is damaged, and the service life of the variable frequency cable is shortened. The existing variable frequency cable outer sheath material mainly comprises PVC sheath material, LSZH (halogen-free low-smoke flame-retardant polyolefin) sheath material, thermoplastic Polyurethane (TPU) sheath material and Chlorinated Polyethylene (CPE) sheath material. The PVC sheath material has low cost, good wear resistance, tear resistance, weather resistance and flame retardance, but has poor high temperature resistance, low Wen Yiying and easy brittleness, contains halogen, generates a large amount of toxic substances during combustion, has poor environmental protection, is gradually replaced, has no halogen and environmental protection, has good flame retardance, extremely low smoke amount during combustion, but has higher cost, and is not environment-friendly because of being filled with a large amount of inorganic strong oxides, has high processing difficulty, general mechanical property, corrosion resistance, waterproofness and the like, has extremely high wear resistance, tear resistance, toughness and good corrosion resistance, but has high cost, general weather resistance, flame retardance and water resistance, has good comprehensive performance, high temperature resistance and flame retardance, has higher cost and general processability, generates toxic gas during combustion, and is not environment-friendly. At present, the semiconductor shielding material (namely the raw material of the insulating shielding layer) of the variable frequency cable is mainly a composite material which takes carbon black as a conductive agent and crosslinked polymer (such as XLPE) as a matrix, can meet most of cable standards, has extremely low cost, but in order to ensure the conductive performance, the carbon black is usually added by 20% -40%, so that the extruded surface is not smooth enough, the toughness is reduced, and the water resistance is poor. When carbon nanotubes, graphene, metal powder, etc. are used as the conductive agent, the cost is extremely high and dispersion is difficult and the quality is unstable, although the addition amount is low. The fireproof variable frequency cable disclosed in the patent CN202311741208.4 has enough fireproof capability by arranging a fireproof unit formed by clamping one layer of asbestos mesh cloth by two layers of glass fiber woven meshes between an outer shielding layer and a protective layer and coating an improved SAR-2 organic silicon paint between the fireproof unit and the outer shielding layer, wherein the fireproof variable frequency cable comprises the asbestos mesh, a plurality of layers of glass fiber woven meshes and a copper strip shielding layer, so that the variable frequency cable has higher hardness and poor flexibility and is not environment-friendly, and in addition, the outermost layer of the cable is the outer shielding layer made of metal materials, so that the problems of mechanical durability, environmental tol