A steel-tape armored crosslinked polyolefin-insulated flame-retardant power cable and a method for manufacturing the same
By modifying cross-linked polyolefin materials and using radiation cross-linking technology, the problem of rigid support and flexible buffering in the gaps between steel strips in armored cables has been solved, improving the cable's bending resistance and insulation flame retardant performance, and achieving excellent electrical and mechanical properties as well as low smoke and non-toxic characteristics.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 安徽华航电缆科技有限公司
- Filing Date
- 2026-05-11
- Publication Date
- 2026-06-23
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Abstract
Description
Technical Field
[0001] This invention relates to the field of power cable technology, and in particular to a steel-tape armored cross-linked polyolefin insulated flame-retardant power cable and its preparation method. Background Technology
[0002] As the core carrier of power and signal transmission, cables play an irreplaceable role in modern industry, construction, communication, transportation and other fields. With the increasing complexity of industrial environments and the high frequency of signal transmission requirements, the protective performance of traditional cables faces severe challenges. Therefore, armored cables, by adding a metal protective layer to the outer layer, effectively improve the cable's resistance to mechanical impact, rodent bites and chemical corrosion, and are widely used in laying applications such as direct burial, tunnels, and shafts where high mechanical protection is required.
[0003] However, when armored cables are subjected to bending deformation during laying or operation, the lack of rigid support at the gaps in the steel strips causes the sheath material to bulge inwards on the bending and tensile side, resulting in localized concentrated tensile deformation. When this deformation exceeds the elongation at break of the sheath material, the sheath begins to crack from the corresponding position in the gap. After the sheath cracks, external moisture and corrosive media can directly penetrate the armor layer and even the insulation layer, causing the cable's waterproof, corrosion-resistant, and flame-retardant functions to fail successively. This defect directly limits the cable's minimum bending radius, making it difficult to adapt to the installation requirements of narrow laying spaces.
[0004] Existing armor structures lack rigid support at the gaps in the steel strips to limit excessive protrusion of the sheath material into the gaps; on the other hand, they lack flexible buffering to evenly distribute bending strain. These two structural defects often lead to bending stress easily forming stress singularities at the gap edges, becoming the source of sheath cracking.
[0005] To address stress concentration at the gaps in the steel strips, current technologies often rely on adding a buffer layer between the steel strip armor layer and the flame-retardant cross-linked polyolefin insulation layer. However, the addition of the buffer layer not only increases material costs and process complexity but also fails to structurally solve the problem of the armor layer lacking rigid support and flexible buffering. Furthermore, the buffer layer material does not have flame-retardant and insulating capabilities, and once the sheath layer cracks and fails, it cannot prevent the spread of flames, thus posing an additional challenge to the insulation and flame-retardant performance of the armored cable.
[0006] Existing technologies attempt to improve the stress distribution of the sheath by optimizing the process parameters of the steel strip armor layer, but simple process optimization cannot improve the flame retardancy, insulation and flexibility of the insulation layer from the material and structural levels.
[0007] Therefore, how to simultaneously improve the electrical, mechanical, flame-retardant, and flexibility properties of the insulation layer at the material level without adding a buffer layer, thereby significantly improving the bending resistance and insulation flame-retardant ability of the cable, is a technical problem that urgently needs to be solved in this field. Summary of the Invention
[0008] The technical problem to be solved by the present invention is that the existing technology has the disadvantages of insufficient bending resistance and insufficient insulation and flame retardancy of steel tape armored power cables. To this end, we propose a steel tape armored cross-linked polyolefin insulated flame retardant power cable and its preparation method.
[0009] To achieve the above objectives, this application adopts the following technical solution: a steel-tape armored cross-linked polyolefin insulated flame-retardant power cable, wherein the cable comprises, from the inside out, a conductor, a flame-retardant cross-linked polyolefin insulation layer, a steel-tape armor layer, and a sheath layer; The flame-retardant cross-linked polyolefin insulation layer and sheath layer are made of modified cross-linked polyolefin. The modified crosslinked polyolefin was prepared by grafting polyolefin with a fluorinated cyclotriphosphazene derivative; The fluorinated cyclic triphosphazene derivative has the structure shown in Formula A:
[0010] Preferably, the conductor is an oxygen-free copper wire.
[0011] Preferably, the fluorinated cyclic triphosphazene derivative is prepared by the following steps: (1) In a reactor, hexachlorocyclotriphosphazene, undecenol, acid-binding agent and organic solvent are added and heated under inert gas protection. After the reaction is completed, the mixture is separated and purified to obtain a single long-chain olefin intermediate. (2) In a reactor, add a single long-chain olefin intermediate, potassium trimethylsilanolate and organic solvent, heat and react under inert gas protection, and after the reaction is completed, separate and purify to obtain a single long-chain olefin diethoxy intermediate; (3) In a reactor, a single long-chain olefin diesiloxy intermediate, a fluorinating agent, a phase transfer catalyst and an organic solvent are added and heated under inert gas protection. After the reaction is completed, the mixture is separated and purified to obtain the fluorinated cyclotriphosphazene derivative.
[0012] Preferably, in step (1), the acid-binding agent is selected from triethylamine or sodium carbonate; the organic solvent is selected from tetrahydrofuran or toluene; the inert gas is selected from nitrogen or argon; the reaction temperature is 20-40℃ and the reaction time is 12-24h; the molar ratio of hexachlorocyclotriphosphazene to undecenol is 1:0.9-1.1.
[0013] Preferably, in step (2), the organic solvent is selected from tetrahydrofuran or toluene; the inert gas is selected from nitrogen or argon; the reaction temperature is 65-90℃ and the reaction time is 6-12h; the molar ratio of the single long-chain olefin intermediate to potassium trimethylsilanolate is 1:1.8-2.2.
[0014] Preferably, in step (3), the fluorinating agent is selected from potassium fluoride, sodium fluoride, or potassium hydrofluoride; the phase transfer catalyst is tetrabutylammonium bromide; the organic solvent is selected from acetonitrile or N,N-dimethylformamide; the inert gas is selected from nitrogen or argon; the reaction temperature is 80-120℃, and the reaction time is 16-24h; the molar ratio of the single long-chain olefin diesiloxy intermediate to the fluorinating agent is 1:3-6.
[0015] Preferably, the modified crosslinked polyolefin is prepared by the following steps: (1) Add polyolefin, fluorinated cyclotriphosphazene derivative and initiator to a high-speed mixer and mix evenly to obtain a premix; (2) The premixed material is added to a twin-screw extruder, and after melt grafting reaction, it is extruded and granulated to obtain the modified cross-linked polyolefin.
[0016] Preferably, in step (1), the polyolefin is a low-density polyolefin; the initiator is dicumyl peroxide; the amount of fluorinated cyclotriphosphazene derivative added is 4-10% of the mass of the polyolefin; and the amount of initiator added is 0.3-1% of the mass of the polyolefin. In step (2), the temperature of the twin-screw extruder is 160-170℃, the screw speed is 150-200rpm, and the melt grafting reaction time is 2-3 minutes.
[0017] Preferably, the degree of crosslinking of the modified crosslinked polyolefin is 55-65%; the grafting rate of the modified crosslinked polyolefin is 2-5%.
[0018] Polyolefins undergo a grafting reaction with fluorinated cyclotriphosphazene derivatives under the action of initiators and melting conditions. Simultaneously, by controlling the melting grafting reaction time, preliminary crosslinking is achieved. The resulting modified crosslinked polyolefins contain some unreacted active sites and grafted siloxane structures, which can provide a reaction basis for subsequent irradiation crosslinking.
[0019] In this invention, polyolefins are melt-grafted and modified using the alkenyl structure of fluorinated cyclotriphosphazene derivatives. This effectively introduces fluorinated cyclotriphosphazene, long-chain alkanes, and siloxane structures into the side chains of polyolefins, resulting in excellent electrical, mechanical, flame-retardant properties and good flexibility after the formation of cross-linked polyolefins.
[0020] Preferably, the steel strip armor layer material is selected from galvanized steel strip or stainless steel strip; the flame-retardant cross-linked polyolefin insulation layer has a thickness of 1.0-1.2 mm; the steel strip armor layer has a thickness of 0.2-0.8 mm; and the sheath layer has a thickness of 1.5-2.5 mm.
[0021] Preferably, the steel strip armor layer material is galvanized steel strip.
[0022] In another aspect, the present invention also provides a method for preparing the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable as described in any one of the above claims, comprising the following steps: (1) The flame-retardant cross-linked polyolefin insulation material is extruded onto the outside of the conductor to form a flame-retardant cross-linked polyolefin insulation layer; (2) Wrap the steel strip armor layer material around the outside of the flame-retardant cross-linked polyolefin insulation layer to form a steel strip armor layer; (3) The sheath material is extruded onto the outside of the steel tape armor layer to form a sheath layer, thus obtaining a cable; (4) The obtained cable is subjected to irradiation crosslinking to obtain the steel tape armored crosslinked polyolefin insulated flame-retardant power cable.
[0023] Preferably, a flame-retardant oxygen barrier layer may be extruded between the conductor and the flame-retardant cross-linked polyolefin insulation layer. By extruding a flame-retardant oxygen barrier layer on the outside of the conductor, the flame-retardant capability of the power cable can be further improved.
[0024] Preferably, the electron beam energy for crosslinking in step (4) is 0.7-0.9 MeV and the irradiation dose is 50-70 kGy.
[0025] Under irradiation, the unreacted sites of the modified crosslinked polyolefin and the siloxane undergo crosslinking.
[0026] In this invention, modified cross-linked polyolefin is used as the flame-retardant cross-linked polyolefin insulation layer and sheath layer material. After being extruded inside and outside the steel tape armor layer, it can partially fill the gaps in the steel tape through radiation cross-linking. Under the action of the siloxane network structure, a stable connection is achieved, which further improves the bending resistance of the power cable. At the same time, it avoids the impact of the addition of a buffer layer on its insulation and flame-retardant capabilities.
[0027] The technical effects and advantages of this invention are as follows: (1) The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention uses cross-linked polyolefin modified with fluorinated cyclotriphosphazene derivatives as the flame-retardant cross-linked polyolefin insulation layer and sheath layer material. Without adding a buffer layer, the problem of stress concentration in the steel tape armor layer leading to sheath layer failure can be improved from both material and structural aspects, thereby significantly improving the bending resistance of the power cable. At the same time, the modified cross-linked polyolefin can further improve the electrical, mechanical and flame-retardant properties of the power cable, making it widely applicable in the field of power cables.
[0028] (2) In the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention, the polyolefin is melt-grafted modified by the alkenyl structure of the fluorinated cyclotriphosphazene derivative, which can effectively introduce fluorinated cyclotriphosphazene, long-chain alkanes and siloxane structures into the side chain of the polyolefin, so that it has excellent electrical, mechanical, flame-retardant properties and good flexibility after forming cross-linked polyolefin.
[0029] (3) In the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention, the fluorinated cyclotriphosphazene derivative can further improve the fire-retardant properties of cross-linked polyolefin based on its polyphosphorus and polynitrogen structure. At the same time, its organic halogen-free flame-retardant mechanism has the advantages of low smoke and non-toxicity. On the other hand, its fluorinated structure can not only improve the thermal stability and hydrophobicity of the material, but also efficiently capture electrons, thereby improving the electrical and mechanical properties and high-temperature resistance of cross-linked polyolefin insulation.
[0030] (4) In the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention, on the one hand, by introducing a flexible long-chain alkane structure and a fluorinated cyclotriphosphazene derivative with large steric hindrance into the side chain of polyolefin, the polyolefin can maintain a certain flexibility when cross-linking to form cross-linked polyolefin, and thus use it as a material for flame-retardant cross-linked polyolefin insulation layer and sheath layer to provide flexible buffering at the gap of steel tape armor layer; on the other hand, the siloxane structure introduced in the side chain can cross-link to form a rigid network structure at the gap of steel tape, which can not only improve the bonding strength between layers, but also provide rigid support for steel tape armor layer. Under the combined effect of flexible buffering and rigid support, the bending resistance of power cable can be effectively improved.
[0031] (5) In the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention, the modified cross-linked polyolefin is used as the flame-retardant cross-linked polyolefin insulation layer and sheath layer material. After being extruded inside and outside the steel tape armor layer, it can be partially filled into the gap of the steel tape through radiation cross-linking, and a stable connection is achieved under the action of the siloxane network structure, which further improves the bending resistance of the power cable, while avoiding the addition of a buffer layer from affecting its electrical, mechanical and flame-retardant insulation capabilities. Detailed Implementation
[0032] It is readily understood that, based on the technical solution of the present invention, those skilled in the art can propose various interchangeable structural methods and implementation methods without altering the essential spirit of the present invention.
[0033] The low-density polyolefin was purchased from Maoming Petrochemical Co., Ltd. of China Petrochemical Corporation, and its grade was 2426K; the other reagents and equipment were conventional reagents and equipment in this technical field.
[0034] Preparation of fluorinated cyclic triphosphazene derivatives Fluorinated cyclic triphosphazene derivatives were prepared by the following steps: (1) In a dry 500mL three-necked flask, add 0.10mol of hexachlorocyclotriphosphazene, 200mL of anhydrous tetrahydrofuran and 0.12mol of triethylamine, and purge with nitrogen for protection. Dissolve 0.09mol of undecenol in 50mL of anhydrous tetrahydrofuran and slowly add it dropwise into the three-necked flask. After the addition is complete, continue the reaction at room temperature for 12h. After the reaction was completed as monitored by TLC, the triethylamine hydrochloride precipitate was removed by filtration, the filtrate was removed by vacuum distillation to remove tetrahydrofuran, the residue was recrystallized twice with n-hexane, and dried under vacuum to give a white solid product, a single long-chain olefin intermediate, in 78.3% yield; (2) In a dry 250mL three-necked flask, add 0.05mol of a single long-chain olefin intermediate and 120mL of anhydrous toluene, purge with nitrogen for protection, stir to dissolve, add 0.11mol of potassium trimethylsilanolate, heat to 80℃, and reflux for 8h. After the reaction was completed as monitored by TLC, the mixture was cooled to room temperature, filtered to remove the potassium chloride precipitate, and the filtrate was distilled under reduced pressure to remove toluene. The residue was washed three times with ethanol and dried under vacuum to give a pale yellow oily liquid single-chain olefin diethoxy intermediate in 82.7% yield. (3) In a dry 250mL three-necked flask, add 0.03mol of a single long-chain olefin diethoxy intermediate, 100mL of anhydrous acetonitrile, 0.18mol of potassium fluoride and 0.003mol of tetrabutylammonium bromide, purge with nitrogen for protection, heat to 90℃, and reflux for 20h. After the reaction was completed by TLC monitoring, the mixture was cooled to room temperature, filtered to remove potassium chloride and unreacted potassium fluoride, and the filtrate was distilled under reduced pressure to remove acetonitrile. The residue was dissolved in n-hexane and purified by silica gel column chromatography (n-hexane / ethyl acetate = 8:1 as eluent). The target fraction was collected, the solvent was removed by reduced pressure distillation, and the product was dried under vacuum to obtain a colorless, transparent, oily liquid product, a fluorinated cyclotriphosphazene derivative, in 71.5% yield.
[0035] Mass spectrometry data of fluorinated cyclotriphosphazene derivatives: HRMS (ESI) - The product was analyzed, and the product was [M-Na]. - The m / z values were 538.15 (100.0%), 539.15 (38.2%), 540.15 (9.1%), and 541.15 (1.5%).
[0036] Infrared spectral data (FT-IR, cm⁻¹) of fluorinated cyclotriphosphazene derivatives -1 The values are 2955, 2870 (CH, saturated alkyl), 1460 (CH2), 1250 (Si-CH3), 1225 (P=N ring skeleton), 1080 (Si-O-Si, Si-OC, POC), 950-880 (PF), 840 (Si-C).
[0037] Preparation of modified crosslinked polyolefin-1 Modified crosslinked polyolefin-1 was prepared by the following steps: (1) 100 parts by weight of low-density polyolefin, 8 parts by weight of fluorinated cyclotriphosphazene derivative and 1 part by weight of dicumyl peroxide are added to a high-speed mixer and mixed evenly to obtain a premix. (2) The premixed material was added to a twin-screw extruder and subjected to a melt grafting reaction at a temperature of 170°C, a screw speed of 200 rpm, and a melt grafting reaction time of 2 minutes. The mixture was then extruded and granulated to obtain the modified crosslinked polyolefin-1. According to the testing standard GB / T 18474-2001, the degree of crosslinking of the modified crosslinked polyolefin-1 is 61.4%, and the grafting rate is 3.5%.
[0038] Preparation of modified crosslinked polyolefin-2 The preparation method is basically the same as that of modified cross-linked polyolefin-1, except that the fluorinated cyclotriphosphazene derivative is replaced with an equal amount of dodecene.
[0039] Preparation of modified crosslinked polyolefin-3 The preparation method is basically the same as that of modified cross-linked polyolefin-1, except that the fluorinated cyclotriphosphazene derivative is replaced with an equal amount of ethoxy (pentafluoro)cyclotriphosphazene. Example 1
[0040] Steel-tape armored cross-linked polyolefin insulated flame-retardant power cables are prepared using the following steps: (1) The modified cross-linked polyolefin-1 is extruded onto the outside of the conductor to form a flame-retardant cross-linked polyolefin insulation layer; (2) The galvanized steel strip is wrapped around the outside of the flame-retardant cross-linked polyolefin insulation layer to form a steel strip armor layer; (3) The modified cross-linked polyolefin-1 is extruded onto the outside of the steel tape armor layer to form a sheath layer, thus obtaining a cable; (4) The obtained cable was subjected to irradiation crosslinking under the conditions of electron beam energy of 0.8MeV and irradiation dose of 60kGy to obtain steel tape armored crosslinked polyolefin insulated flame-retardant power cable; The flame-retardant cross-linked polyolefin insulation layer has a thickness of 1.0 mm, the steel tape armor layer has a thickness of 0.2 mm, and the sheath layer has a thickness of 2.0 mm. Example 2
[0041] (1) The modified cross-linked polyolefin-1 is extruded onto the outside of the conductor to form a flame-retardant cross-linked polyolefin insulation layer; (2) Wrap the stainless steel strip around the outside of the flame-retardant cross-linked polyolefin insulation layer to form a steel strip armor layer; (3) The modified cross-linked polyolefin-1 is extruded onto the outside of the steel tape armor layer to form a sheath layer, thus obtaining a cable; (4) The obtained cable was subjected to irradiation crosslinking under the conditions of electron beam energy of 0.7MeV and irradiation dose of 70kGy to obtain steel tape armored crosslinked polyolefin insulated flame-retardant power cable. The flame-retardant cross-linked polyolefin insulation layer has a thickness of 1.2 mm, the steel tape armor layer has a thickness of 0.5 mm, and the sheath layer has a thickness of 1.5 mm. Example 3
[0042] (1) The modified cross-linked polyolefin-1 is extruded onto the outside of the conductor to form a flame-retardant cross-linked polyolefin insulation layer; (2) The galvanized steel strip is wrapped around the outside of the flame-retardant cross-linked polyolefin insulation layer to form a steel strip armor layer; (3) The modified cross-linked polyolefin-1 is extruded onto the outside of the steel tape armor layer to form a sheath layer, thus obtaining a cable; (4) The obtained cable was subjected to irradiation crosslinking under the conditions of electron beam energy of 0.9MeV and irradiation dose of 50kGy to obtain steel tape armored crosslinked polyolefin insulated flame-retardant power cable. The flame-retardant cross-linked polyolefin insulation layer has a thickness of 1.1 mm, the steel tape armor layer has a thickness of 0.8 mm, and the sheath layer has a thickness of 2.5 mm.
[0043] Comparative Example 1 The process is basically the same as in Example 1, except that the modified cross-linked polyolefin-1 is replaced with a low-density polyolefin.
[0044] Comparative Example 2 The basic formula is the same as in Example 1, except that modified cross-linked polyolefin-1 is replaced with modified cross-linked polyolefin-2.
[0045] Comparative Example 3 The process is basically the same as in Example 1, except that modified cross-linked polyolefin-1 is replaced with modified cross-linked polyolefin-3.
[0046] Performance testing Bending resistance test: The samples of the products of Examples 1-3 and Comparative Examples 1-3 were subjected to bending tests respectively. The bending radius when the sheath layer showed cracks was recorded as the minimum bending radius. The result of minimum bending radius / cable outer diameter was calculated as the bending multiple.
[0047] High temperature resistance test: The samples of the products of Examples 1-3 and Comparative Examples 1-3 were placed in an environment of 60°C and heated at 5°C / 30min. The temperature at which the cable resistance changed was recorded as the long-term operating temperature. In the same way, the temperature was increased at 5°C / 1min and the temperature at which a short circuit occurred was recorded as the short circuit temperature.
[0048] The test results are shown in Table 1 below:
[0049] According to the comparison of the test results of Examples 1-3 and Comparative Example 1, the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention, by modifying the cross-linked polyolefin as a flame-retardant cross-linked polyolefin insulation layer and protective sheath material, can significantly improve the bending resistance and high temperature resistance of the cross-linked polyolefin power cable, and further expand its application range.
[0050] According to the comparison of the test results of Examples 1-3 and Comparative Examples 2-3, the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention modifies the cross-linked polyolefin by fluorinated cyclotriphosphazene derivatives. Based on the structure of its long-chain alkyl, siloxane and fluorinated cyclotriphosphazene, the flexibility of the cross-linked polyolefin can be effectively improved, and the bending resistance and high temperature resistance of the steel-tape armored power cable can be improved through the synergistic effect of materials and structure.
[0051] Flame retardant performance test: Referring to the standard GB / T 19666-2019 for flame retardant and fire-resistant wires and cables, the flame retardant performance of individual wires of Examples 1-3 and Comparative Examples 1-3 was tested respectively. The distance between the upper and lower carbonization points was recorded to determine whether it met the standard that the distance between the lower edge of the upper clamp and the starting point of the upper carbonization is greater than 50mm and the distance between the lower edge of the upper clamp and the starting point of the lower carbonization is not greater than 540mm.
[0052] Breakdown field strength test: Referring to the standard GB / T 1408-2016, the product samples of Examples 1-3 and Comparative Examples 1-3 were placed between electrodes and immersed in insulating oil. A power frequency voltage was applied at a rate of 1kV / s until the flame-retardant cross-linked polyolefin insulation layer broke down, and the breakdown field strength was calculated.
[0053] The test results are shown in Table 2 below:
[0054] According to the comparison of the test results of Examples 1-3 and Comparative Example 1, the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention, by modifying the cross-linked polyolefin as a flame-retardant cross-linked polyolefin insulation layer and protective sheath material, can significantly improve the insulation and flame-retardant capabilities of the steel-tape armored cross-linked polyolefin power cable.
[0055] According to the comparison of the test results of Examples 1-3 and Comparative Examples 2-3, it can be seen that in the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable provided by the present invention, the cross-linked polyolefin is modified by fluorinated cyclotriphosphazene derivatives. Based on its long-chain alkyl, siloxane and fluorinated cyclotriphosphazene structure, the insulation and flame-retardant ability of the cross-linked polyolefin can be effectively improved.
[0056] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.
Claims
1. A steel-tape armored cross-linked polyolefin insulated flame-retardant power cable, characterized in that, The cable, from the inside out, comprises a conductor, a flame-retardant cross-linked polyolefin insulation layer, a steel tape armor layer, and a sheath layer; The flame-retardant cross-linked polyolefin insulation layer and sheath layer are made of modified cross-linked polyolefin. The modified crosslinked polyolefin was prepared by grafting polyolefin with a fluorinated cyclotriphosphazene derivative; The fluorinated cyclic triphosphazene derivative has the structure shown in Formula A:
2. The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to claim 1, characterized in that, The fluorinated cyclic triphosphazene derivative is prepared by the following steps: (1) In a reactor, hexachlorocyclotriphosphazene, undecenol, acid-binding agent and organic solvent are added and heated under inert gas protection. After the reaction is completed, the mixture is separated and purified to obtain a single long-chain olefin intermediate. (2) In a reactor, add a single long-chain olefin intermediate, potassium trimethylsilanolate and organic solvent, heat and react under inert gas protection, and after the reaction is completed, separate and purify to obtain a single long-chain olefin diethoxy intermediate; (3) In a reactor, a single long-chain olefin diesiloxy intermediate, a fluorinating agent, a phase transfer catalyst and an organic solvent are added and heated under inert gas protection. After the reaction is completed, the mixture is separated and purified to obtain the fluorinated cyclotriphosphazene derivative.
3. The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to claim 2, characterized in that, In step (1), the acid-binding agent is selected from triethylamine or sodium carbonate; the organic solvent is selected from tetrahydrofuran or toluene; the inert gas is selected from nitrogen or argon; the reaction temperature is 20-40℃ and the reaction time is 12-24h; the molar ratio of hexachlorocyclotriphosphazene to undecenol is 1:0.9-1.
1.
4. The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to claim 2, characterized in that, In step (2), the organic solvent is selected from tetrahydrofuran or toluene; the inert gas is selected from nitrogen or argon; the reaction temperature is 65-90℃ and the reaction time is 6-12h; the molar ratio of the single long-chain olefin intermediate to potassium trimethylsilanolate is 1:1.8-2.
2.
5. The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to claim 2, characterized in that, In step (3), the fluorinating agent is selected from potassium fluoride, sodium fluoride or potassium hydrofluoride; the phase transfer catalyst is tetrabutylammonium bromide; the organic solvent is selected from acetonitrile or N,N-dimethylformamide; the inert gas is selected from nitrogen or argon; the reaction temperature is 80-120℃ and the reaction time is 16-24h; the molar ratio of the single long-chain olefin diesiloxy intermediate to the fluorinating agent is 1:3-6.
6. The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to claim 1, characterized in that, The modified crosslinked polyolefin is prepared by the following steps: (1) Add polyolefin, fluorinated cyclotriphosphazene derivative and initiator to a high-speed mixer and mix evenly to obtain a premix; (2) The premixed material is added to a twin-screw extruder, and after melt grafting reaction, it is extruded and granulated to obtain the modified cross-linked polyolefin.
7. The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to claim 6, characterized in that, In step (1), the polyolefin is a low-density polyolefin; the initiator is dicumyl peroxide; the amount of fluorinated triphosphazene derivative added is 4-10% of the mass of the polyolefin; and the amount of initiator added is 0.3-1% of the mass of the polyolefin. In step (2), the temperature of the twin-screw extruder is 160-170℃, the screw speed is 150-200rpm, and the melt grafting reaction time is 2-3 minutes.
8. The steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to claim 1, characterized in that, The steel strip armor layer material is selected from either galvanized steel strip or stainless steel strip; the flame-retardant cross-linked polyolefin insulation layer has a thickness of 1.0-1.2 mm; the steel strip armor layer has a thickness of 0.2-0.8 mm; and the sheath layer has a thickness of 1.5-2.5 mm.
9. The method for preparing the steel-tape armored cross-linked polyolefin insulated flame-retardant power cable according to any one of claims 1-8, characterized in that, Includes the following steps: (1) The flame-retardant cross-linked polyolefin insulation material is extruded onto the outside of the conductor to form a flame-retardant cross-linked polyolefin insulation layer; (2) Wrap the steel strip armor layer material around the outside of the flame-retardant cross-linked polyolefin insulation layer to form a steel strip armor layer; (3) The sheath material is extruded onto the outside of the steel tape armor layer to form a sheath layer, thus obtaining a cable; (4) The obtained cable is subjected to irradiation crosslinking to obtain the steel tape armored crosslinked polyolefin insulated flame-retardant power cable.
10. The preparation method according to claim 9, characterized in that, In step (4), the electron beam energy for crosslinking by irradiation is 0.7-0.9 MeV, and the irradiation dose is 50-70 kGy.