High-flame-retardant electric wire and cable and preparation method thereof

Abstract

The invention relates to the technical field of cables, and provides a high-flame-retardant wire cable and a preparation method thereof. The invention relates to a high-flame-retardant wire and cable, which sequentially comprises a conductor, an insulating layer, a shielding layer, a fire-resistant layer, an armor layer and a sheath layer from inside to outside, the conductor is a copper conductor, the insulating layer is a cross-linked polyethylene insulating layer, and the sheath layer is prepared from the following raw materials in parts by weight: 100 parts of polyvinyl chloride resin, 20-30 parts of ethylene propylene diene monomer, 10-15 parts of ethylene-ethyl acrylate copolymer, 20-30 parts of flame retardant, 10-15 parts of filler, 1-3 parts of cross-linking agent, 1-2 parts of lubricant and 3-5 parts of stabilizer. According to the technical scheme, the problem of insufficient flame retardance of the sheath layer in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of cable technology, specifically to a high flame-retardant wire and cable and its preparation method. Background Technology

[0002] As a key carrier of power transmission and information communication, wires and cables are widely used in high-rise buildings, rail transportation, public facilities, industrial mines, and other fields. However, with the continuous growth of power load, the increasing integration of equipment, and the growing awareness of safety and environmental protection in modern society, higher requirements are being placed on the safety and reliability of wires and cables in complex environments.

[0003] Currently, polyvinyl chloride (PVC) resin is widely used as the sheathing material for wires and cables due to its excellent mechanical properties, good weather resistance, superior electrical insulation properties, and ease of processing. However, this type of material suffers from insufficient flame retardancy, making it prone to combustion under overload, short circuit, or external ignition sources, potentially leading to the spread of fire. This can damage the wires and cables themselves and cause fires and other safety accidents. Therefore, developing a wire and cable with high flame retardancy is of great significance. Summary of the Invention

[0004] This invention proposes a high flame-retardant wire and cable and its preparation method, which solves the problem of insufficient flame retardancy of the sheath layer in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a high flame-retardant wire and cable, which comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer. The conductor is a copper conductor, the insulation layer is a cross-linked polyethylene insulation layer, and the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 20-30 parts of ethylene propylene diene monomer (EPDM) rubber, 10-15 parts of ethylene-ethyl acrylate copolymer, 20-30 parts of flame retardant, 10-15 parts of filler, 4-6 parts of compatibilizer, 1-3 parts of cross-linking agent, 1-2 parts of lubricant, and 3-5 parts of stabilizer.

[0006] As a further technical solution, the material of the shielding layer is galvanized copper wire.

[0007] As a further technical solution, the material of the refractory layer is mica tape.

[0008] As a further technical solution, the armor layer is a tin-plated copper wire braided armor layer.

[0009] As a further technical solution, the flame retardant is obtained by modifying chitosan sequentially with polyphosphoric acid and guanidine carbonate; The flame retardant comprises the following raw materials in parts by weight: 10-15 parts chitosan, 30-40 parts polyphosphate, and 15-20 parts guanidine carbonate.

[0010] This invention improves the flame retardancy of wire and cable sheaths by adding chitosan, modified sequentially with polyphosphoric acid and guanidine carbonate, as a flame retardant. Chitosan, as a biomass carbon source with high carbon content, synergistically works with polyphosphoric acid to provide sufficient carbon for char formation and promote the formation of a char layer, thus effectively improving the flame retardancy of polyphosphoric acid. However, chitosan itself has a tendency to agglomerate, which limits the further improvement of the flame retardant's properties. Therefore, by sequentially modifying it with polyphosphoric acid and guanidine carbonate, the phosphate groups in polyphosphoric acid can undergo esterification with the hydroxyl groups on the surface of chitosan, improving its dispersibility and decomposing to produce acidic substances upon heating. This catalyzes the rapid dehydration and carbonization of chitosan, promoting char layer formation and improving flame retardancy. The addition of guanidine carbonate, upon heating, decomposes to release inert gases such as nitrogen, diluting the concentration of oxygen and combustible gases, enhancing the heat and oxygen insulation properties of the char layer, and further improving the flame retardancy of the sheath.

[0011] As a further technical solution, the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3~4, preferably 2:8:3.5.

[0012] As a further technical solution, the preparation method of the flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in solvent I, chitosan is added and reacted to obtain premix I. A2. After dispersing guanidine carbonate in solvent II evenly, premixed solution II is obtained; A3. After cooling the premixed liquid I, add it to the premixed liquid II and mix. Then, wash, filter and dry to obtain the flame retardant.

[0013] As a further technical solution, in step A1, solvent I is water.

[0014] As a further technical solution, in step A1, the reaction temperature is 120~130℃ and the reaction time is 1.5~2.5h.

[0015] As a further technical solution, in step A3, the mixing temperature is 65~75℃ and the mixing time is 1~2h.

[0016] As a further technical solution, the ethylene-ethyl acrylate copolymer is composed of a first ethylene-ethyl acrylate copolymer and a second ethylene-ethyl acrylate copolymer, wherein the mass content of ethyl acrylate in the first ethylene-ethyl acrylate copolymer and the second ethylene-ethyl acrylate copolymer is different.

[0017] As a further technical solution, the mass content of ethyl acrylate in the first ethylene-ethyl acrylate copolymer is 15%, and the mass content of ethyl acrylate in the second ethylene-ethyl acrylate copolymer is 19.5%.

[0018] The present invention improves the wear resistance of the sheath layer by adding a first ethylene-ethyl acrylate copolymer with a mass content of 15% ethyl acrylate and a second ethylene-ethyl acrylate copolymer with a mass content of 19.5% ethyl acrylate. The first ethylene-ethyl acrylate copolymer, due to its relatively low proportion of flexible ethyl acrylate segments and stronger molecular chain rigidity, significantly improves the hardness of the sheath layer and enhances its resistance to external friction and scratching. The second ethylene-ethyl acrylate copolymer, with its higher proportion of flexible ethyl acrylate segments, effectively buffers and disperses stress through molecular chain deformation when the sheath layer is subjected to frictional forces, preventing cracking and damage caused by localized stress concentration. The compounded second ethylene-ethyl acrylate copolymer effectively avoids the problem of insufficient sheath layer toughness and cracking under repeated friction caused by the excessive rigidity of the first ethylene-ethyl acrylate copolymer, leading to decreased wear resistance. The first ethylene-ethyl acrylate copolymer compensates for the insufficient scratch resistance of the sheath layer due to the excessive flexibility of the second ethylene-ethyl acrylate copolymer. Therefore, this invention improves the wear resistance of the cable sheath layer by compounding the first and second ethylene-ethyl acrylate copolymers.

[0019] As a further technical solution, the mass ratio of the first ethylene-ethyl acrylate copolymer to the second ethylene-ethyl acrylate copolymer is 6:7~9, preferably 3:4.

[0020] As a further technical solution, the filler is carbon black.

[0021] As a further technical solution, the compatibilizer includes one or two of maleic anhydride-grafted polyethylene and maleic anhydride-grafted ethylene-acrylate copolymer.

[0022] As a further technical solution, the crosslinking agent includes one or two of dicumyl peroxide and bis-tert-butylperoxide.

[0023] As a further technical solution, the lubricant is polyethylene wax.

[0024] As a further technical solution, the stabilizer is a calcium-zinc composite stabilizer.

[0025] This invention also proposes a method for preparing a high flame-retardant wire and cable, comprising the following steps: S1. Extruding the insulating material onto the outside of the copper conductor and cross-linking it to form a cross-linked polyethylene insulating layer; S2. Wrap the shielding layer material around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap the refractory material around the outside of the shielding layer to form a refractory layer; S4. The armor layer material is woven into the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form a sheath layer, and a high flame-retardant wire and cable is obtained.

[0026] The working principle and beneficial effects of this invention are as follows: This invention provides a high flame-retardant cable, which comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer, forming a multi-layered synergistic protection system. The conductor is made of copper, ensuring excellent conductivity and reliability. The insulation layer is made of cross-linked polyethylene, possessing excellent electrical insulation and heat resistance. The shielding layer effectively suppresses electromagnetic interference, ensuring signal transmission quality. The fire-resistant layer maintains structural integrity at high temperatures, delaying flame spread. The armor layer enhances the cable's mechanical strength and resistance to external damage. The sheath layer uses polyvinyl chloride resin as the base material, compounded with EPDM rubber and ethylene-ethyl acrylate copolymer to form a composite protective matrix, improving the flame-retardant performance of the sheath layer. The various layers work together to achieve high flame retardancy and stable transmission performance of the cable. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0028] In the following examples and comparative examples: Polyvinyl chloride resin, model: SG-5; ethylene propylene diene monomer (EPDM) rubber, model: 3745P; ethylene-ethyl acrylate copolymer of the first type, model: AC2615, with an ethyl acrylate content of 15%; ethylene-ethyl acrylate copolymer of the second type, model: AC2103, with an ethyl acrylate content of 19.5%; carbon black, average particle size 20nm; maleic anhydride-grafted polyethylene, model: 4107, grafting rate 1.0%; polyethylene wax, model: LP0040P; calcium-zinc composite stabilizer, model: CZ-1059; polyphosphoric acid, tetrapolyphosphoric acid, molecular weight: 337.93; chitosan, degree of deacetylation: 90%, average particle size: 100 mesh.

[0029] Example 1 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 20 parts of ethylene propylene diene monomer (EPDM) rubber, 10 parts of ethylene-ethyl acrylate copolymer, 20 parts of flame retardant, 10 parts of carbon black, 4 parts of maleic anhydride-grafted polyethylene, 1 part of dicumyl peroxide, 1 part of polyethylene wax, and 3 parts of calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 120℃ for 2.5h to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, the mixture is mixed at 65°C for 2 hours. After washing, filtering and drying, the flame retardant is obtained, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0030] Example 2 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 25 parts of ethylene propylene diene monomer (EPDM) rubber, 12 parts of ethylene-ethyl acrylate copolymer, 25 parts of flame retardant, 13 parts of carbon black, 5 parts of maleic anhydride-grafted polyethylene, 2 parts of dicumyl peroxide, 1.5 parts of polyethylene wax, and 4 parts of calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 125℃ for 2 hours to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0031] Example 3 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts polyvinyl chloride resin, 30 parts ethylene propylene diene monomer (EPDM) rubber, 15 parts ethylene-ethyl acrylate copolymer, 30 parts flame retardant, 15 parts carbon black, 6 parts maleic anhydride-grafted polyethylene, 3 parts dicumyl peroxide, 2 parts polyethylene wax, and 5 parts calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 130℃ for 1.5h to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 75°C for 1 hour, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0032] Example 4 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 25 parts of ethylene propylene diene monomer (EPDM) rubber, 12 parts of ethylene-ethyl acrylate copolymer, 25 parts of flame retardant, 13 parts of carbon black, 5 parts of maleic anhydride-grafted polyethylene, 2 parts of dicumyl peroxide, 1.5 parts of polyethylene wax, and 4 parts of calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 125℃ for 2 hours to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter, and dry to obtain the flame retardant, wherein the mass ratio of chitosan, polyphosphate, and guanidine carbonate is 2:8:3.5. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0033] Example 5 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 25 parts of ethylene propylene diene monomer (EPDM) rubber, 12 parts of ethylene-ethyl acrylate copolymer, 25 parts of flame retardant, 13 parts of carbon black, 5 parts of maleic anhydride-grafted polyethylene, 2 parts of dicumyl peroxide, 1.5 parts of polyethylene wax, and 4 parts of calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 125℃ for 2 hours to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 1:4:2. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0034] Example 6 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 100 parts polyvinyl chloride resin, 25 parts ethylene propylene diene monomer (EPDM) rubber, 12 parts ethylene-ethyl acrylate copolymer, 25 parts flame retardant, 13 parts carbon black, 5 parts maleic anhydride-grafted polyethylene, 2 parts dicumyl peroxide, 1.5 parts polyethylene wax, and 4 parts calcium-zinc composite stabilizer. The ethylene-ethyl acrylate copolymer is a second ethylene-ethyl acrylate copolymer. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 125℃ for 2 hours to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0035] Example 7 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 100 parts polyvinyl chloride resin, 25 parts ethylene propylene diene monomer (EPDM) rubber, 12 parts ethylene-ethyl acrylate copolymer, 25 parts flame retardant, 13 parts carbon black, 5 parts maleic anhydride-grafted polyethylene, 2 parts dicumyl peroxide, 1.5 parts polyethylene wax, and 4 parts calcium-zinc composite stabilizer. The ethylene-ethyl acrylate copolymer is composed of a first ethylene-ethyl acrylate copolymer and a second ethylene-ethyl acrylate copolymer in a mass ratio of 6:7. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 125℃ for 2 hours to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0036] Example 8 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 100 parts polyvinyl chloride resin, 25 parts EPDM rubber, 12 parts ethylene-ethyl acrylate copolymer, 25 parts flame retardant, 13 parts carbon black, 5 parts maleic anhydride-grafted polyethylene, 2 parts dicumyl peroxide, 1.5 parts polyethylene wax, and 4 parts calcium-zinc composite stabilizer. The ethylene-ethyl acrylate copolymer is composed of a first ethylene-ethyl acrylate copolymer and a second ethylene-ethyl acrylate copolymer in a mass ratio of 3:4. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 125℃ for 2 hours to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0037] Example 9 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer. The raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 25 parts of ethylene propylene diene monomer (EPDM) rubber, 12 parts of ethylene-ethyl acrylate copolymer, 25 parts of flame retardant, 13 parts of carbon black, 5 parts of maleic anhydride-grafted polyethylene, 2 parts of dicumyl peroxide, 1.5 parts of polyethylene wax, and 4 parts of calcium-zinc composite stabilizer. The ethylene-ethyl acrylate copolymer is composed of a first ethylene-ethyl acrylate copolymer and a second ethylene-ethyl acrylate copolymer in a mass ratio of 2:3. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in water, chitosan is added and reacted at 125℃ for 2 hours to obtain premixed solution I, in which the mass-volume ratio of chitosan to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of chitosan, polyphosphate and guanidine carbonate is 2:8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0038] Comparative Example 1 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 25 parts of ethylene propylene diene monomer (EPDM) rubber, 12 parts of ethylene-ethyl acrylate copolymer, 25 parts of flame retardant, 13 parts of carbon black, 5 parts of maleic anhydride-grafted polyethylene, 2 parts of dicumyl peroxide, 1.5 parts of polyethylene wax, and 4 parts of calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. The preparation method of the flame retardant includes the following steps: after polyphosphoric acid is added to water and dispersed evenly, chitosan is added and reacted at 125°C for 2 hours. After washing, filtering and drying, the flame retardant is obtained, wherein the mass-volume ratio of chitosan to water is 1g:6mL; and the mass ratio of chitosan to polyphosphoric acid is 2:8. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of a copper conductor and cross-linking it to form a cross-linked polyethylene insulation layer; S2. Wrap galvanized copper wire around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0039] Comparative Example 2 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 25 parts of ethylene propylene diene monomer (EPDM) rubber, 12 parts of ethylene-ethyl acrylate copolymer, 25 parts of polyphosphoric acid, 13 parts of carbon black, 5 parts of maleic anhydride-grafted polyethylene, 2 parts of dicumyl peroxide, 1.5 parts of polyethylene wax, and 4 parts of calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of the copper conductor to form an insulating layer; S2. Wrap the copper strip around the outside of the insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0040] Comparative Example 3 A high flame-retardant wire and cable comprises, from the inside out, a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer; the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 25 parts of ethylene propylene diene monomer (EPDM) rubber, 12 parts of ethylene-ethyl acrylate copolymer, 25 parts of flame retardant, 13 parts of carbon black, 5 parts of maleic anhydride-grafted polyethylene, 2 parts of dicumyl peroxide, 1.5 parts of polyethylene wax, and 4 parts of calcium-zinc composite stabilizer; the ethylene-ethyl acrylate copolymer is a first type of ethylene-ethyl acrylate copolymer. The preparation method of flame retardant includes the following steps: A1. After dispersing polyphosphoric acid in water, a premixed solution I is obtained, wherein the mass-volume ratio of polyphosphoric acid to water is 1g:6mL. A2. After dispersing guanidine carbonate in water evenly, premixed solution II is obtained, wherein the mass-volume ratio of guanidine carbonate to water is 1g:4mL. A3. After adding premix I to premix II, mix at 70°C for 1.5 hours, then wash, filter and dry to obtain flame retardant, wherein the mass ratio of polyphosphoric acid and guanidine carbonate is 8:3. A method for preparing a high flame-retardant wire and cable includes the following steps: S1. Extruding cross-linked polyethylene material onto the outside of the copper conductor to form an insulating layer; S2. Wrap the copper strip around the outside of the insulation layer to form a shielding layer; S3. Wrap mica tape around the outside of the shielding layer to form a fire-resistant layer; S4. Weave tin-plated copper wire onto the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form the sheath layer, and a high flame-retardant wire and cable is obtained.

[0041] Experimental Example 1 The sheath layers of the high flame-retardant wires and cables prepared in Examples 1-9 and Comparative Examples 1-3 were tested according to the following method: 1. Flame retardant performance: The oxygen index was tested according to GB / T 2406.2-2009 "Determination of burning behavior of plastics by oxygen index method - Part 2: Room temperature test". The sample shape was IV, and the ignition method was Method A, top surface ignition method. The test results are the average of 3 samples, and the test results are shown in Table 1 below. 2. Wear resistance: Mass wear test was carried out according to GB / T 3960-2016 "Plastics Sliding Friction and Wear Test Method". During the test, the test ring was made of 45# steel, the test ring rotated at 200 r / min, the test time was 2h, and the load was 196N. The test results are shown in Table 2 below.

[0042] Table 1. Test results of flame retardant properties of the cable sheath in Examples 1-5 and Comparative Examples 1-3.

[0043] The oxygen index of Examples 1-5 is higher than that of Comparative Examples 1-3, indicating that the present invention improves the flame retardancy of the high flame retardant wire and cable sheath by adding chitosan modified successively by polyphosphoric acid and guanidine carbonate as a flame retardant.

[0044] Table 2. Test results of abrasion resistance of the cable sheath in Examples 2, 6-9

[0045] The wear resistance of the sheath layer in Examples 7-9 was lower than that in Examples 2 and 6, indicating that the present invention improves the wear resistance of the sheath layer by adding a first ethylene-ethyl acrylate copolymer with a mass content of 15% ethyl acrylate and a second ethylene-ethyl acrylate copolymer with a mass content of 19.5% ethyl acrylate.

[0046] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high flame retardant electrical wire cable characterized by, From the inside out, it includes a conductor, an insulation layer, a shielding layer, a fire-resistant layer, an armor layer, and a sheath layer. The conductor is a copper conductor, the insulation layer is a cross-linked polyethylene insulation layer, and the raw materials of the sheath layer include the following components by weight: 100 parts of polyvinyl chloride resin, 20-30 parts of ethylene propylene diene monomer (EPDM) rubber, 10-15 parts of ethylene-ethyl acrylate copolymer, 20-30 parts of flame retardant, 10-15 parts of filler, 4-6 parts of compatibilizer, 1-3 parts of cross-linking agent, 1-2 parts of lubricant, and 3-5 parts of stabilizer.

2. A high flame retardant electrical wire cable according to claim 1, wherein, The shielding layer is made of galvanized copper wire.

3. A high flame retardant electrical wire cable according to claim 1, wherein, The refractory layer is made of mica tape.

4. A high flame retardant electrical wire cable according to claim 1, wherein, The armor layer is a tin-plated copper wire braided armor layer.

5. A high flame-retardant wire and cable according to claim 1, characterized in that, The flame retardant is obtained by modifying chitosan sequentially with polyphosphoric acid and guanidine carbonate; The flame retardant comprises the following raw materials in parts by weight: 10-15 parts chitosan, 30-40 parts polyphosphate, and 15-20 parts guanidine carbonate.

6. A high flame retardant electrical wire cable according to claim 5, wherein, The mass ratio of chitosan, polyphosphate, and guanidine carbonate is 2:8:3~4.

7. A high flame retardant electrical wire cable according to claim 6, wherein, The method for preparing the flame retardant includes the following steps: A1. After dispersing polyphosphoric acid evenly in solvent I, chitosan is added and reacted to obtain premix I. A2. After dispersing guanidine carbonate in solvent II evenly, premixed solution II is obtained; A3. After mixing the premixed liquid I with the premixed liquid II, the mixture is washed, filtered, and dried to obtain the flame retardant.

8. A high flame-retardant wire and cable according to claim 7, characterized in that, In step A1, the reaction temperature is 120~130℃ and the reaction time is 1.5~2.5h.

9. A high flame retardant electrical wire cable according to claim 7, wherein, In step A3, the mixing temperature is 65~75℃ and the mixing time is 1~2h.

10. A process for producing a high flame retardant electric wire cable for producing the high flame retardant electric wire cable according to any one of claims 1 to 9, characterized by, Includes the following steps: S1. Extruding the insulating material onto the outside of the copper conductor and cross-linking it to form a cross-linked polyethylene insulating layer; S2. Wrap the shielding layer material around the outside of the cross-linked polyethylene insulation layer to form a shielding layer; S3. Wrap the refractory material around the outside of the shielding layer to form a refractory layer; S4. The armor layer material is woven into the outside of the refractory layer to form an armor layer; S5. After the raw materials of the sheath layer are mixed evenly, they are melt-extruded and coated on the outside of the armor layer, cross-linked, to form a sheath layer, and a high flame-retardant wire and cable is obtained.

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