Cross-linked polyethylene insulated flame-retardant power cable

Abstract

The invention relates to the technical field of power cables, and provides a cross-linked polyethylene insulated flame-retardant power cable which sequentially comprises a cable core, an inner protective layer, a shielding layer, an insulating layer and a protective layer from inside to outside, the cable core is composed of a conductor and a cross-linked polyethylene insulating layer wrapping the conductor, and a filling material is arranged between the cable core and the inner protective layer. The shielding layer is of an aluminum alloy wire net structure, and the raw materials of the insulating layer comprise the following components: polyethylene, a cross-linking agent and an inorganic flame retardant. According to the technical scheme, the problem that the flame retardance of the cross-linked polyethylene insulated cable is low in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power cable, in particular, it relates to a kind of cross-linked polyethylene insulation flame-retardant power cable. BACKGROUND

[0002] As the key carrier of power transmission and distribution, the performance of power cable is directly related to the reliable operation of power system. With the acceleration of urbanization, the continuous expansion of industrial production scale and the promotion of various large-scale infrastructure construction, the demand for power cable continues to grow.

[0003] Cross-linked polyethylene insulation power cable is a kind of power transmission cable with cross-linked polyethylene as the core insulation material. It is widely used in power transmission and distribution of power system due to its high insulation, but it has the problem of insufficient flame retardancy, which will significantly increase the risk of fire.

[0004] Therefore, the present application proposes a kind of cross-linked polyethylene insulation power cable with high flame retardancy to reduce the risk of fire and ensure the safe and reliable operation of power system. SUMMARY

[0005] The present application proposes a kind of cross-linked polyethylene insulation flame-retardant power cable, which solves the problem of low flame retardancy of cross-linked polyethylene insulation cable in related art.

[0006] The technical scheme of the present application is as follows: The present application proposes a kind of cross-linked polyethylene insulation flame-retardant power cable, which includes cable core, inner protective layer, shielding layer, insulation layer and protective layer from inside to outside. The cable core is composed of conductor and cross-linked polyethylene insulation layer wrapped outside the conductor. The cable core and the inner protective layer are provided with filling material. The shielding layer is in the form of aluminum alloy wire mesh. The raw materials of the insulation layer include the following components: polyethylene, cross-linking agent and inorganic flame retardant.

[0007] As a further technical scheme, the conductor is obtained by concentrically twisting 10-20 tinned copper wires, and the diameter of the tinned copper wire is 0.5-1.5 mm.

[0008] In the present application, 10-20 thin copper wires with a diameter of 0.5-1.5 mm are twisted, which significantly improves the flexibility compared to a single thick conductor. When the conductor is bent, each single wire can disperse stress through small deformation, reducing the risk of conductor breakage caused by bending. The concentric twisting method can make the single wires closely adhere to each other, and the tensile strength is better than that of a single conductor, which can reduce the risk of wire breakage caused by external force stretching.

[0009] As a further technical scheme, the shielding layer is woven by aluminum alloy wires with a single wire diameter of 0.3-0.4 mm.

[0010] The fine diameter design of the monofilament in the shielding layer is 0.3-0.4 mm, the weaving structure is more dense, a uniform shielding layer can be formed on the surface of the cable, when the cable is subjected to external impact, the impact force can be dispersed by the elastic deformation of the monofilament, and the direct damage to the internal insulation layer and the core can be reduced; and the melting point of the shielding layer is high, when a fire occurs, the dense woven shielding layer can act as a physical barrier to delay the speed of the flame directly contacting the internal insulation layer and the core.

[0011] As a further technical solution, the material of the inner protective layer is cross-linked polyethylene.

[0012] As a further technical solution, the protective layer is prepared from a polyethylene material.

[0013] As a further technical solution, the raw materials of the inorganic flame retardant include magnesium hydroxide, silane coupling agent and 4-aminobenzyl diethyl phosphate.

[0014] As a further technical solution, the preparation method of the inorganic flame retardant comprises the following steps: adding the silane coupling agent and the 4-aminobenzyl diethyl phosphate into a solvent and dispersing uniformly, then adding the magnesium hydroxide and mixing, and drying to obtain the inorganic flame retardant.

[0015] In the application, the magnesium hydroxide is modified by the silane coupling agent and the 4-aminobenzyl diethyl phosphate at the same time, which can better solve the problem of poor compatibility of magnesium hydroxide with the resin, not only can better play the flame-retardant effect of magnesium hydroxide, further improve the flame retardancy, but also can improve the tensile strength of the cable.

[0016] As a further technical solution, the mass ratio of the silane coupling agent and the 4-aminobenzyl diethyl phosphate to the magnesium hydroxide is 3%-5%, for example, it can be 3%, 3.5%, 4%, 4.5% or 5%.

[0017] As a further technical solution, the mass ratio of the silane coupling agent to the 4-aminobenzyl diethyl phosphate is 5:1-3, for example, it can be 5:1, 5:1.5, 5:2, 5:2.5 or 5:3, preferably 5:2.

[0018] As a further technical solution, the solvent is an ethanol aqueous solution, and the ethanol aqueous solution is obtained by mixing anhydrous ethanol and water in a volume ratio of 3:1.

[0019] As a further technical solution, the mass-to-volume ratio of the magnesium hydroxide to the solvent is 1g:8mL.

[0020] As a further technical solution, the mixing time is 2h, 2.5h or 3h, and the mixing temperature is 35-45℃, for example, it can be 35℃, 40℃ or 45℃.

[0021] As a further technical solution, the raw material of the insulation layer further comprises 4-5 parts of a compound containing benzene ring and amino group.

[0022] As a further technical solution, the compound containing benzene ring and amino group is preferably 1,3-bis(3-aminophenoxy)benzene.

[0023] As a further technical solution, the raw material of the insulation layer comprises the following components by weight: polyethylene 100 parts, inorganic flame retardant 20-30 parts, crosslinking agent 1.5-2 parts, antioxidant 1-1.5 parts.

[0024] As a further technical solution, the crosslinking agent comprises one or more of dicumyl peroxide, 1,3-bis(tert-butylperoxy isopropyl) benzene, 1,4-bis(tert-butylperoxy isopropyl) benzene, tert-butyl peroxybenzoate.

[0025] The working principle and beneficial effects of the present application are as follows: The crosslinked polyethylene insulation flame-retardant power cable in the present application comprises a core, an inner protective layer, a shielding layer, an insulation layer, and a protective layer from the inside to the outside, forming a gradient insulation protection of a multi-layer structure. The shielding layer of the aluminum alloy mesh structure can form a physical barrier to delay the penetration rate of the flame. The inorganic flame retardant added to the raw material of the insulation layer will undergo endothermic decomposition at high temperatures, releasing crystallization water and absorbing a large amount of heat, reducing the temperature of the surface of the insulation layer, delaying the speed of reaching the material ignition point, and the mesh structure formed by crosslinking the polyethylene in the raw material of the insulation layer also helps to improve the flame retardant effect, thereby improving the flame retardancy of the crosslinked polyethylene insulation flame-retardant power cable of the present application. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor also fall within the scope of protection of the present application.

[0027] In the following examples and comparative examples: Polyethylene: LD608 low density polyethylene, Yanshan Petrochemical; Magnesium hydroxide: particle size 325 mesh.

[0028] Example 1 The crosslinked polyethylene insulation flame-retardant power cable comprises, from inside to outside, a cable core, an inner sheath layer, a shielding layer, an insulation layer and a protective layer, wherein the cable core is composed of a conductor and a crosslinked polyethylene insulation layer wrapped outside the conductor, and the conductor is obtained by concentrically twisting 16 tin-plated copper wires with a diameter of 1 mm; the inner sheath layer is prepared by extruding a crosslinked polyethylene material outside the cable core; a filling material (the filling material is an aramid filling rope) is arranged between the cable core and the inner sheath layer; the shielding layer is an aluminum alloy mesh structure woven by aluminum alloy wires with a diameter of 0.3 mm; the insulation layer is prepared by extruding a crosslinked polyethylene insulation layer material outside the shielding layer; and the protective layer is prepared by extruding a polyethylene material outside the insulation layer. The insulation layer comprises the following raw materials in parts by weight: 100 parts of polyethylene, 30 parts of inorganic flame retardant, 1.5 parts of dicumyl peroxide and 1 part of antioxidant 1010; wherein the inorganic flame retardant is magnesium hydroxide. The preparation method of the insulation layer comprises the following steps: uniformly mixing polyethylene, inorganic flame retardant and antioxidant 1010, adding dicumyl peroxide again, extruding outside the shielding layer through a double-screw extruder, crosslinking at 170 DEG C and 15 MPa for 35 min, and obtaining the insulation layer.

[0029] Example 2 The crosslinked polyethylene insulation flame-retardant power cable comprises, from inside to outside, a cable core, an inner sheath layer, a shielding layer, an insulation layer and a protective layer, wherein the cable core is composed of a conductor and a crosslinked polyethylene insulation layer wrapped outside the conductor, and the conductor is obtained by concentrically twisting 16 tin-plated copper wires with a diameter of 1 mm; the inner sheath layer is prepared by extruding a crosslinked polyethylene material outside the cable core; a filling material (the filling material is an aramid filling rope) is arranged between the cable core and the inner sheath layer; the shielding layer is an aluminum alloy mesh structure woven by 4 aluminum alloy wires with a diameter of 0.4 mm; the insulation layer is prepared by extruding a crosslinked polyethylene insulation layer material outside the shielding layer; and the protective layer is prepared by extruding a polyethylene material outside the insulation layer. The insulation layer comprises the following raw materials in parts by weight: 100 parts of polyethylene, 30 parts of inorganic flame retardant, 2 parts of dicumyl peroxide and 1.5 parts of antioxidant 1010; wherein the inorganic flame retardant is magnesium hydroxide. The preparation method of the insulation layer comprises the following steps: uniformly mixing polyethylene, inorganic flame retardant and antioxidant 1010, adding dicumyl peroxide again, extruding outside the shielding layer through a double-screw extruder, crosslinking at 170 DEG C and 15 MPa for 35 min, and obtaining the insulation layer.

[0030] Example 3 The difference between the present embodiment and Example 1 is only inorganic flame retardant. The preparation method of the inorganic flame retardant of the present embodiment comprises the following steps: adding silane coupling agent KH-550 into an aqueous ethanol solution (mixed by 3:1 of anhydrous ethanol and water by volume) and uniformly dispersing, then adding magnesium hydroxide and mixing, drying to obtain the inorganic flame retardant; wherein the mass of the silane coupling agent is 3% of the mass of the magnesium hydroxide, and the mass-volume ratio of the magnesium hydroxide to the aqueous ethanol solution is 1g:8mL.

[0031] Example 4 The difference between the present embodiment and Example 3 is only that the silane coupling agent KH-550 is replaced by an equal amount of 4-aminobenzyl diethyl phosphate.

[0032] Example 5 The difference between the present embodiment and Example 3 is only that the silane coupling agent KH-550 is replaced by an equal amount of 4-aminobenzyl diethyl phosphate.

[0033] Example 6 The difference between the present embodiment and Example 3 is only that the silane coupling agent KH-550 is replaced by an equal amount of 4-aminobenzyl diethyl phosphate.

[0034] Example 7 The difference between the present embodiment and Example 3 is only that the silane coupling agent KH-550 is replaced by an equal amount of 4-aminobenzyl diethyl phosphate.

[0035] Example 8 The difference between the present embodiment and Example 6 is only in the following: The insulating layer comprises the following components by weight: 100 parts of polyethylene, 20 parts of inorganic flame retardant, 1.5 parts of dicumyl peroxide, 1 part of antioxidant 1010, and 4 parts of 1,3-bis(3-aminophenoxy)benzene. The preparation method of the insulating layer comprises the following steps: mixing polyethylene, inorganic flame retardant, antioxidant 1010, and 1,3-bis(3-aminophenoxy)benzene uniformly, then adding dicumyl peroxide and mixing again, extruding through a double-screw extruder to coat the outside of the shielding layer, and then crosslinking at 170°C and 15MPa for 35min to obtain the insulating layer.

[0036] Example 9 The difference between the present embodiment and Example 8 is only that 1,3-bis(3-aminophenoxy)benzene is replaced by an equal amount of silane coupling agent KH-550.

[0037] Experimental Example The performance of the insulation layer obtained in Examples 1-9 was determined, and the determination method was as follows: (1) Flame-retardant performance: the oxygen index test was performed according to the method of GB / T 2406.2-2009 "Plastics - Determination of the burning behavior in terms of flammability - Part 2: test method - horizontal and vertical method", and the sample shape was IV; (2) Tensile strength: the tensile strength test was performed according to the method in GB / T 2951.11-2008 "Cables and optical fibers - Determination of the mechanical properties - Part 11: general test methods - measurement of thickness and outer dimensions - mechanical property tests", and the sample to be tested was a dumbbell test piece with a thickness of 3 mm; The determination results are shown in Table 1.

[0038] Table 1 Determination results of the oxygen index of the insulation layer

[0039] Compared with Example 1, Example 3 only used a silane coupling agent to modify magnesium hydroxide, Example 4 only used 4-aminobenzyl diethyl phosphate to modify magnesium hydroxide, and Example 5 used a silane coupling agent and 4-aminobenzyl diethyl phosphate to modify magnesium hydroxide at the same time. The results showed that the oxygen index of the insulation layer in Example 5 was higher than that in Examples 1, 3-4, indicating that the simultaneous use of a silane coupling agent and 4-aminobenzyl diethyl phosphate to modify magnesium hydroxide can improve the flame retardance of the insulation layer.

[0040] Table 2 Determination results of the tensile strength of the insulation layer

[0041] Compared with Example 1, Example 3 only used a silane coupling agent to modify magnesium hydroxide, Example 4 only used 4-aminobenzyl diethyl phosphate to modify magnesium hydroxide, and Example 6 used a silane coupling agent and 4-aminobenzyl diethyl phosphate to modify magnesium hydroxide at the same time. The results showed that the tensile strength of the insulation layer in Example 6 was higher than that in Examples 1, 3-4, indicating that the simultaneous use of a silane coupling agent and 4-aminobenzyl diethyl phosphate to modify magnesium hydroxide can improve the tensile strength of the insulation layer.

[0042] Compared with Example 6, Example 8 also added 1,3-bis(3-aminophenoxy)benzene, and Example 9 also added silane coupling agent KH-550. The results showed that the tensile strength of the insulation layer in Example 8 was higher than that in Examples 6 and 9, indicating that the addition of a compound containing a benzene ring and an amino group can improve the tensile strength of the insulation layer.

[0043] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A cross-linked polyethylene insulated flame-retardant power cable, characterized in that, From the inside out, the cable consists of a cable core, an inner sheath, a shielding layer, an insulation layer, and a protective layer. The cable core is composed of a conductor and a cross-linked polyethylene insulation layer covering the conductor. A filler material is provided between the cable core and the inner sheath. The shielding layer has an aluminum alloy wire mesh structure. The raw materials of the insulation layer include the following components: polyethylene, cross-linking agent, and inorganic flame retardant.

2. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that, The conductor is formed by concentrically stranding 10 to 20 tin-plated copper wires, the diameter of which is 0.5 to 1.5 mm.

3. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that, The shielding layer is woven from aluminum alloy wires with a single filament diameter of 0.3~0.4mm.

4. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that, The inner protective layer is made of cross-linked polyethylene.

5. A cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that, The protective layer is made of polyethylene material.

6. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that, The raw materials for the inorganic flame retardant include magnesium hydroxide, silane coupling agent, and diethyl 4-aminobenzyl phosphate.

7. A cross-linked polyethylene insulated flame-retardant power cable according to claim 6, characterized in that, The mass ratio of the silane coupling agent and diethyl 4-aminobenzyl phosphate to magnesium hydroxide is 3% to 5%.

8. A cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that, The preparation method of the inorganic flame retardant includes the following steps: adding silane coupling agent and diethyl 4-aminobenzyl phosphate into a solvent and dispersing them evenly, then adding magnesium hydroxide and mixing, and drying to obtain the inorganic flame retardant.

9. A cross-linked polyethylene insulated flame-retardant power cable according to claim 8, characterized in that, The mixing time is 2-3 hours, and the mixing temperature is 35-45℃.

10. A cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that, The raw materials of the insulating layer also include 4 to 5 parts of compounds containing benzene rings and amino groups.

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