A medium-low voltage composite fire-resistant cable and a preparation method thereof

Abstract

The application discloses a kind of medium-low voltage composite fire-resistant cable and preparation method thereof, with wire as core layer (1), from core layer outwardly in turn first shielding layer (2), insulating layer (3), fire-resistant layer (4), second shielding layer (5), outer sheath layer (6), the first shielding layer (2) is vinyl semi-conductive shielding layer;The first insulating layer (3) is crosslinked polyethylene insulating layer;The fire-resistant layer (4) is the porcelainizing glass fiber woven polyethylene layer that is fused in double-layer glass fiber woven cloth by low-melting point glass powder / porecelain filler / magnesium hydroxide fusion bonding;The second shielding layer (5) is copper fiber layer (wound by copper fiber tape);The outer sheath layer (6) is crosslinked flame-retardant polyethylene composite material layer.The medium-low voltage composite fire-resistant cable of the application has excellent fire resistance, easy processability by novel fire-resistant layer structure, flame-retardant crosslinked outer layer protective sleeve structure, and is suitable for new energy charger cable material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite cables, in particular to a medium and low voltage composite fire-resistant cable and a preparation method thereof. BACKGROUND

[0002] New energy electric vehicles have been supported by various countries and regions due to their advantages of low energy consumption, low carbon emission and low noise. The rapid development of the electric vehicle industry has also increased the demand for electric vehicle charging pile cables. Medium and low voltage cables are cables used in power systems for transmitting voltage levels of ≤35kV and are widely used in power distribution networks, industrial power supply and new energy power stations.

[0003] Because charging pile cables are exposed to outdoor environments for a long time and require high load current, the conductor is prone to heat during cable power operation, which may cause a fire if not discovered in time. Therefore, higher requirements are placed on the flame retardation and fire resistance of electric vehicle charging pile cables. Currently, the internal structure of general low-smoke halogen-free fire-resistant power cables mainly uses a fire-resistant layer wrapped around the conductor, and a low-smoke halogen-free material is used for the outer sheath to achieve the performance of fire resistance, low smoke and non-toxicity. However, the fire-resistant layer of the existing technology has the following defects:

[0004] 1. In order to further improve the fire resistance, high content of fillers, glass fibers and porcelain fillers are required, but this will cause the melt flowability to decrease, the surface roughness to be high after co-extrusion, and the material to be prone to caking.

[0005] 2. The high content of glass fibers and porcelain fillers in the fire-resistant layer of the existing technology is poorly dispersed, and the glass fibers are prone to form a single radial distribution during extrusion, making it difficult to form a cross network structure, which makes it difficult to form a solid protective layer during the fire resistance test and is prone to collapse.

[0006] 3. The fire resistance of the mica fire-resistant tape used in the fire-resistant layer of the existing technology is insufficient. SUMMARY

[0007] The present application aims to overcome the above technical defects and provide a medium and low voltage composite fire-resistant cable with good fire resistance and easy processing, as well as a preparation method thereof.

[0008] The present application is achieved by the following technical solutions:

[0009] A medium and low voltage composite fire-resistant cable, with a wire as a core layer (1), a first shielding layer (2), an insulation layer (3), a fire-resistant layer (4), a second shielding layer (5) and an outer sheath layer (6) from the core layer outward in sequence,

[0010] The first shielding layer (2) is a vinyl semi-conductive shielding layer.

[0011] The insulation layer (3) is a cross-linked polyethylene insulation layer.

[0012] The fire-resistant reinforcing layer (4) is a porcelainized glass fiber fabric polyethylene layer fused in double-layer glass fiber fabric by low-melting-point glass powder / porecelainizing filler / magnesium hydroxide.

[0013] The second shielding layer (5) is a copper fiber layer.

[0014] The outer sheath layer (6) is a cross-linked flame-retardant polyethylene composite material layer.

[0015] The wire can be a copper wire, which can be a single wire or a copper wire bundle.

[0016] The vinyl semi-conductive shielding layer comprises polyethylene 40-50 wt%, ethylene-vinyl acetate copolymer 20-30 wt%, conductive carbon black 20-30 wt%, cross-linking agent 0.5-1 wt%, and peroxide cross-linking initiator 0.7-1.1 wt%.

[0017] The particle size of the conductive carbon black is required to be between 1-50 nm, and the volume resistivity is ≤0.5 Ω·cm.

[0018] The preparation method of the vinyl semi-conductive shielding layer is as follows: the above components are mixed, then melt-extruded through a double-screw extruder, cooled, and pelletized, and then vulcanized and cross-linked to obtain vinyl semi-conductive shielding layer particles; the melt-extrusion temperature is 120-140℃; the vulcanization and cross-linking process is as follows: hot-pressed at >15 MPa and 110-125℃ for 5-10 min in a flat vulcanization machine, and then cross-linked at 170-180℃ for 10-20 min to obtain a sheet-shaped vinyl semi-conductive shielding layer.

[0019] The insulation layer (3) is a cross-linked polyethylene insulation layer, which comprises the following components: polyethylene resin 80-90 wt%, maleic anhydride grafted polyethylene 2-4 wt%, peroxide cross-linking initiator 1.4-3 wt%, cross-linking agent 0.5-1 wt%, nano-magnesium oxide (particle size 10-300 nm) 1-2 wt%, montmorillonite (particle size 1-50 microns) 5-10 wt%, and lubricant 0.1-0.3 wt%.

[0020] The preparation method of the cross-linked polyethylene insulation layer raw material is as follows: the components are uniformly mixed, melt-extruded at 120-175℃ through a double-screw extruder, pelletized, and cooled.

[0021] The refractory layer (4) is a ceramicized glass fiber cloth polyethylene layer, which comprises 10-15 wt% of polyethylene resin, 30-40 wt% of glass fiber cloth, 15-30 wt% of ceramic filler, 10-20 wt% of low-melting-point glass powder with a melting point of 500-700℃, 5-10 wt% of magnesium hydroxide, and 1-2 wt% of Fe2O3; the ceramic filler is selected from any one or more of kaolin, mica powder, and wollastonite.

[0022] The preparation method of the ceramicized glass fiber cloth polyethylene layer is as follows: according to the weight percentage, the ceramic filler, the low-melting-point glass powder, the magnesium hydroxide, the Fe2O3, and 0.5-1.5 wt% of a coupling agent are mixed in a mixer at 30-50℃ for 10-30 min to obtain a mixed filler; the glass fiber cloth is laid flat, the surface is covered with the mixed filler, and then a layer of glass fiber cloth is covered, and after compaction, the glass fiber cloth is baked at 800-1000℃ for 20-40 min, and then soaked in polyethylene resin, and cut to obtain the glass fiber cloth polyethylene belt.

[0023] The copper fiber layer of the second shielding layer (5) can be further wrapped with a layer of semiconductive Teflon tape between the copper fiber layer and the refractory reinforcing layer (4). Wrapping the refractory layer (4) with one or more layers of semiconductive Teflon tape and then winding the copper fiber layer can reduce the wear of the copper fiber layer on the refractory reinforcing layer (4). An adhesive can also be applied.

[0024] The raw materials of the cross-linked flame-retardant polyethylene composite layer include 45-55 wt% of polyethylene resin, 40-50 wt% of aluminum hydroxide, 1-2 wt% of maleic anhydride grafted polyethylene, 1-2 wt% of peroxide cross-linking initiator, 0.5-1 wt% of cross-linking agent, and 0.1-0.5 wt% of lubricant.

[0025] The preparation method of the raw materials of the cross-linked flame-retardant polyethylene composite layer is as follows: the components are uniformly mixed, and then melted, extruded, granulated, and cooled through a double-screw extruder at 120-175℃.

[0026] The peroxide cross-linking initiator is selected from any one of the following: di-tert-butyl peroxide diisopropylbenzene, dicumyl peroxide, lauroyl peroxide, dicumyl peroxide, and dibenzoyl peroxide.

[0027] The cross-linking agent is selected from any one of the following: triallyl cyanurate, triallyl isocyanurate, methyl triallyl isocyanurate, trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, and 1,6-hexanediol diacrylate.

[0028] The lubricant is selected from any one of calcium stearate, magnesium stearate, zinc stearate, ethylene bis-stearamide and pentaerythritol stearate.

[0029] The preparation method of the medium-low voltage composite fire-resistant cable comprises the following steps:

[0030] Step A: co-extruding the wire, the vinyl semi-conductive shielding layer particles and the cross-linked polyethylene insulation layer particles (the temperature is the processing temperature of the raw materials of each layer + 0-10 DEG C), and performing overall heating, extrusion and cooling forming to obtain a cable semi-finished product A;

[0031] Step B: winding the cable semi-finished product A through the glass fiber woven polyethylene layer, the semi-conductive special Teflon tape layer (optional, or brushing the adhesive) and the copper fiber layer in sequence to obtain a cable semi-finished product B;

[0032] Step C: extruding the cross-linked flame-retardant polyethylene composite material layer through the extruder to obtain the medium-low voltage composite fire-resistant cable.

[0033] The medium-low voltage composite fire-resistant cable can also be used as a core, and a plurality of cores are wrapped together through a tie (which can be a mica tape, a glass fiber tape or the like), and are filled (such as alkali-free glass fiber, fire-resistant filler, water-resistant filler, flame-retardant filler or the like) in the plurality of combined cores and the mica tape layer to obtain a cable core, and then the fire-resistant layer, the shielding layer and the outer sheath are wrapped to obtain a combined cable.

[0034] The medium-low voltage composite fire-resistant cable has the following beneficial effects:

[0035] In the application, the low-melting-point glass powder / porcelain-forming filler / magnesium hydroxide / Fe2O3 are blended through the coupling agent, and part of the Fe2O3 promotes part of the low-melting-point glass powder to melt after high-temperature baking, so that the porcelain-forming filler and the magnesium hydroxide are fixed on the surface of the glass fiber woven cloth, and then the glass fiber woven polyethylene layer is formed by immersing the polyethylene resin. In the process of the fire resistance test, the porcelain-forming filler, the low-melting-point glass powder and the magnesium hydroxide in the glass fiber woven polyethylene layer are uniformly blended and closely combined, and can quickly form a solid fire-resistant network under high-temperature flame, and the strength is high and does not collapse, so that the fire resistance is effectively improved. Moreover, the glass fiber woven polyethylene layer of the application also has good wrapping properties (smooth coating, non-rough surface) and tensile resistance. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 : cross-sectional view of the medium-low voltage composite fire-resistant cable, 1, core layer, 2, first shielding layer, 3, insulation layer, 4, fire-resistant layer, 5, second shielding layer, 6, outer sheath layer. DETAILED DESCRIPTION

[0037] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0038] The raw material formula and source of the vinyl semiconductive shielding layer are as follows:

[0039] Polyethylene: content 45wt%, XJ710, purchased from Lotte in South Korea;

[0040] Ethylene-vinyl acetate copolymer: content 25wt%, VS430, purchased from Lotte in South Korea;

[0041] Conductive carbon black: content 28wt%, specific surface area 50-80m 2 / g, commercially available;

[0042] Crosslinking agent: content 1wt%, triallyl cyanurate, commercially available;

[0043] Peroxide crosslinking initiator: content 1wt%, dicumyl peroxide, commercially available;

[0044] The preparation process is: after mixing the components, melt extrusion is performed through a double-screw extruder, cooling, pelletizing, and then vulcanization crosslinking to obtain vinyl semiconductive shielding layer particles; wherein the melt extrusion temperature is 120-140℃; the vulcanization crosslinking process is: hot pressing at 18MPa and 110℃ for 10min in a flat vulcanizing machine, and then crosslinking at 170-180℃ for 10min to obtain a sheet-shaped vinyl semiconductive shielding layer.

[0045] The raw material formula and source of the crosslinked polyethylene insulating layer are as follows:

[0046] Polyethylene: content 85wt%, XJ710, purchased from Lotte in South Korea;

[0047] Maleic anhydride grafted polyethylene: content 3wt%, MC218, Ningbo Nengzhiguang;

[0048] Peroxide crosslinking initiator: content 1wt%, dicumyl peroxide, commercially available;

[0049] Crosslinking agent: content 2wt%, triallyl cyanurate, commercially available;

[0050] Nano-magnesium oxide: content 1wt%, particle size 70-90nm, commercially available;

[0051] Montmorillonite: content 7.8wt%, particle size 10-15 microns, commercially available;

[0052] Lubricant: 0.2wt%, PETS AHS, Italy;

[0053] The preparation process is: mix the components uniformly, melt extrude through a twin-screw extruder at 120-175℃, granulate, cool.

[0054] The raw material formula and source of the ceramicized glass fiber woven polyethylene layer are as follows:

[0055] Polyethylene: XJ710, purchased from Lotte, South Korea;

[0056] Glass fiber woven cloth: density 15-20 strands / cm horizontally / vertically, glass fiber filament diameter 12 microns.

[0057] Ceramic filler: kaolin, particle size 20-25 microns, commercially available;

[0058] Low-melting-point glass powder-A: melting point 500℃, D250, Anmi Micro-Nano New Materials;

[0059] Low-melting-point glass powder-B: melting point 700℃, D270, Anmi Micro-Nano New Materials;

[0060] Low-melting-point glass powder-C: melting point 350℃, D235, Anmi Micro-Nano New Materials;

[0061] Low-melting-point glass powder-D: melting point 880℃, FD106, Anmi Micro-Nano New Materials;

[0062] Magnesium hydroxide: particle size 12-20 microns, commercially available;

[0063] Fe2O3: particle size 27 microns, commercially available;

[0064] Coupling agent: KH560, commercially available;

[0065] The preparation method of the ceramicized glass fiber woven polyethylene layer is: the ceramic filler, low-melting-point glass powder, magnesium hydroxide, and 0.5-1.5wt% coupling agent are mixed in a mixer at 50℃ for 10min to obtain a mixed filler; the glass fiber woven cloth is laid flat, the surface is covered with the mixed filler, and then a layer of glass fiber woven cloth is covered, and after compaction, it is baked at 800-1000℃ (C450℃, D1100℃, H without heating) for 30min, and then immersed in polyethylene resin after cooling, and the glass fiber woven polyethylene belt is obtained after cutting.

[0066] Table 1: Parameters of glass fiber woven polyethylene belt

[0067]

[0068] The melting point of the low-melting-point glass powder is too low, which can cause excessive melting during the baking process, resulting in too hard and too brittle ceramicized glass fiber fabric polyethylene tape, which is difficult to wrap evenly. If the baking temperature is reduced to 450°C, the binding of other materials will be poor and loose, which will also lead to a decrease in refractory performance. When the melting point of the low-melting-point glass powder exceeds 700°C, the baking temperature needs to be >1000°C and the baking time needs to be extended to effectively melt the powder, but it is difficult to control uniform melting and melting amount, and the powder is not tightly combined, so the refractory structure formed during the refractory test is not strong enough, and the refractory structure is easily collapsed during the refractory test, which is broken by voltage.

[0069] The raw material formula and source of the cross-linked flame-retardant polyethylene composite layer are as follows:

[0070] Polyethylene: content 50wt%, XJ710, purchased from South Korea Lotte;

[0071] Aluminum hydroxide: content 45wt%, 20-25 microns, commercially available;

[0072] Maleic anhydride grafted polyethylene: content 3wt%, MC218, Ningbo Nengzhi Light;

[0073] Cross-linking initiator: content 1wt%, dicumyl peroxide, commercially available;

[0074] Cross-linking agent: content 0.7wt%, triallyl cyanurate, commercially available;

[0075] Lubricant: content 0.3wt%, PETS AHS, Italy Fa;

[0076] Preparation method of raw materials of cross-linked flame-retardant polyethylene composite layer: mix the components uniformly, melt extrude, granulate, and cool at 120-175°C through a double-screw extruder.

[0077] Preparation method of low-voltage composite refractory cable: step A: the copper wire is drawn by a traction machine, and is co-extruded with vinyl semi-conductive shielding layer particles and cross-linked polyethylene insulation layer particles (the temperature is the processing temperature of each layer raw material + 0~10°C), and is integrally heated, extruded, and cooled to form a cable semi-finished product A; step B: the cable semi-finished product A is wound by glass fiber fabric polyethylene layer (two layers, A / B / C / D / E / F / G / H) and copper fiber layer (single layer) in sequence to obtain a cable semi-finished product B; step C: the cable semi-finished product B is extruded by an extruder to coat a cross-linked flame-retardant polyethylene composite layer to obtain a medium-low voltage composite refractory cable A / B / C / D / E / F / G / H.

[0078] Fire resistance test: Fire resistance test according to TIC W8-2012, double jet flame, flame temperature > 950℃ (test time 180 min), AC voltage applied between copper conductor and second shielding layer. Acceptance: requirement (1) no breakdown of the applied voltage Uo (8.7 kV) during the entire test duration, requirement (2) after cooling for 15 min after the end of the test, 3.5 Uo (30.5 kV) is applied for 15 min without breakdown of the test sample.

[0079] Test results are:

[0080] Medium and low voltage composite fire resistant cable A: Uo not breakdown during the test of 180 min, 3.5 Uo 15 min not breakdown.

[0081] Medium and low voltage composite fire resistant cable B: Uo not breakdown during the test of 180 min, 3.5 Uo 15 min not breakdown.

[0082] Medium and low voltage composite fire resistant cable C: 31 min breakdown.

[0083] Medium and low voltage composite fire resistant cable D: 70 min breakdown.

[0084] Medium and low voltage composite fire resistant cable E: 63 min breakdown.

[0085] Medium and low voltage composite fire resistant cable F: 53 min breakdown.

[0086] Medium and low voltage composite fire resistant cable G: 78 min breakdown.

[0087] Medium and low voltage composite fire resistant cable H: 47 min breakdown.

[0088] It is shown that the melting point of low melting point glass powder is related to whether the powder can be closely combined. E / F / G shows that magnesium hydroxide, kaolin and ferric oxide play a synergistic role. It is difficult to form a strong fire-resistant layer without any of them, which is because: magnesium hydroxide as a flame retardant improves the effect of flame-retardant porcelain; kaolin as a porcelain filler quickly forms a porcelain heat insulation layer, and if the content of kaolin is insufficient, the porcelain performance will be insufficient; ferric oxide can effectively improve the combination of various powders and glass fiber fabrics during baking. Without adding ferric oxide, the powder after baking is loose and cannot quickly form a solid porcelain layer during the fire resistance test, which is easy to collapse. H shows that the combination of low melting point glass powder and other powders in the preparation process is the key to quickly forming a strong fire-resistant layer during the fire resistance test.

Claims

1. A medium-low voltage composite fire-resistant cable, taking a conductor as a core layer (1), and sequentially from the core layer outward, a first shielding layer (2), an insulation layer (3), a fire-resistant layer (4), a second shielding layer (5), and an outer sheath layer (6), characterized in that the first shielding layer (2) is a vinyl semi-conductive shielding layer; the insulation layer (3) is a cross-linked polyethylene insulation layer; the fire-resistant layer (4) is a porcelainizing glass fiber fabric polyethylene layer fused in double-layer glass fiber fabric by low-melting point glass powder / porecelainizing filler / magnesium hydroxide; the second shielding layer (5) is a copper fiber layer; and the outer sheath layer (6) is a cross-linked flame-retardant polyethylene composite material layer. The fire-resistant layer (4) comprises the following components: 10-15 wt% polyethylene resin, 30-40 wt% glass fiber fabric, 15-30 wt% porcelainizing filler, 10-20 wt% low-melting point glass powder with a melting point of 500-700℃, 5-10 wt% magnesium hydroxide, and 1-2 wt% Fe2O3; the porcelainizing filler is selected from any one or more of kaolin, mica powder, and wollastonite; and the preparation method of the porcelainizing glass fiber fabric polyethylene layer is as follows: according to the weight percentage, the porcelainizing filler, low-melting point glass powder, magnesium hydroxide, Fe2O3, and 0.5-1.5 wt% coupling agent are mixed in a mixer at 30-50℃ for 10-30 min to obtain a mixed filler; the glass fiber fabric is laid flat, the surface is spread with the mixed filler, and then covered with another layer of glass fiber fabric; after compaction, the glass fiber fabric is baked at 800-1000℃ for 20-40 min; and after cooling, the glass fiber fabric is impregnated with polyethylene resin, cut, and then the glass fiber fabric polyethylene tape is obtained. The vinyl semi-conductive shielding layer comprises 40-50 wt% polyethylene, 20-30 wt% ethylene-vinyl acetate copolymer, 20-30 wt% conductive carbon black, 0.5-1 wt% cross-linking agent, and 0.7-1.1 wt% peroxide cross-linking initiator. The insulation layer (3) is a cross-linked polyethylene insulation layer comprising the following components: 80-90 wt% polyethylene resin, 2-4 wt% maleic anhydride grafted polyethylene, 1.4-3 wt% peroxide cross-linking initiator, 0.5-1 wt% cross-linking agent, 1-2 wt% nano-magnesium oxide, 5-10 wt% montmorillonite, and 0.1-0.3 wt% lubricant. The copper fiber layer of the second shielding layer (5) further comprises a semi-conductive Xidong tape layer and / or an adhesive between the copper fiber layer and the fire-resistant layer (4). The cross-linked flame-retardant polyethylene composite material layer comprises 45-55 wt% polyethylene resin, 40-50 wt% aluminum hydroxide, 1-2 wt% maleic anhydride grafted polyethylene, 1-2 wt% peroxide cross-linking initiator, 0.5-1 wt% cross-linking agent, and 0.1-0.5 wt% lubricant. ​ 2. The medium-low voltage composite fire resistant cable of claim 1, wherein, ​ 3. The medium-low voltage composite fire resistant cable of claim 1, wherein, ​ 4. The medium-low voltage composite fire resistant cable of claim 1, wherein, ​ 5. The medium-low voltage composite fire resistant cable of claim 1, wherein, ​ 6. Medium-low voltage composite fire resistant cable according to claim 3 or 5, characterized in that, The peroxide crosslinking initiator is selected from any one of the following: di-tert-butyl peroxide diisopropylbenzene, dicumyl peroxide, lauroyl peroxide, dicumyl peroxide, dibenzoyl peroxide; the crosslinking agent is selected from any one of the following: triallyl cyanurate, triallyl isocyanurate, methyl triallyl isocyanurate, trimethylolpropane triacrylate, propoxylated trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate; the lubricant is selected from any one of the following: calcium stearate, magnesium stearate, zinc stearate, ethylene bis-stearamide, pentaerythritol stearate.

7. The preparation method of the medium-low voltage composite fire-resistant cable according to any one of claims 1-6, characterized in that, Step A: co-extruding the conductor, the vinyl semi-conductive shielding layer and the crosslinked polyethylene insulation layer, and performing overall heating, extrusion and cooling to form a cable semi-product A; Step B: winding the cable semi-product A with glass fiber woven polyethylene and copper fiber in sequence to obtain a cable semi-product B; Step C: obtaining the medium-low voltage composite fire-resistant cable by extruding a crosslinked flame-retardant polyethylene composite material layer on the cable semi-product B.

8. The method of manufacturing a medium-low voltage composite fire resistant cable according to claim 7, characterized in that, The preparation method of the vinyl semi-conductive shielding layer is: mixing the components, melting extruding through a double-screw extruder, cooling, granulating, and then vulcanizing and crosslinking to obtain vinyl semi-conductive shielding layer particles; the melting extrusion temperature is 120-140°C; the vulcanization and crosslinking process is: hot pressing at >15 MPa and 110-125°C for 5-10 min in a flat vulcanizing machine, and then crosslinking at 170-180°C for 10-20 min to obtain a sheet-shaped vinyl semi-conductive shielding layer; The preparation method of the crosslinked polyethylene insulation layer raw material is: uniformly mixing the components, melting extruding through a double-screw extruder at 120-175°C, granulating and cooling; The preparation method of the ceramicized glass fiber woven polyethylene layer is: mixing the ceramic filler, low-melting-point glass powder, magnesium hydroxide, Fe2O3 and 0.5-1.5 wt% coupling agent in a mixer at 30-50°C for 10-30 min to obtain a mixed filler; laying the glass fiber woven cloth flat, spreading the mixed filler on the surface, and then covering another layer of glass fiber woven cloth; after compaction, baking at 800-1000°C for 20-40 min, and then soaking in polyethylene resin, cutting to obtain a glass fiber woven polyethylene tape.

9. The method of manufacturing a medium-low voltage composite fire resistant cable according to claim 7, characterized in that, The preparation method of the crosslinked flame-retardant polyethylene composite material layer raw material is: uniformly mixing the components, melting extruding through a double-screw extruder at 120-175°C, granulating and cooling.

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