Fire-fighting special double flame-retardant power cable and preparation method thereof

Abstract

The present application relates to the technical field of power cable, in particular to a double flame-retardant power cable for fire fighting and a preparation method thereof, which comprises a circular conductor, an insulation shielding layer, a metal layer, a metal armor layer and a polyethylene flame-retardant outer protective layer arranged from inside to outside; the polyethylene flame-retardant outer protective layer is prepared by mixing P / N / S / Si quaternary modified boron nitride flame retardant and linear low-density polyethylene in a mixing mill, heating and melting, and extruding; the preparation of the flame retardant comprises: preparing P / N / S / Si quaternary flame-retardant material by substitution reaction of P / N / S three flame-retardant element modified DOPO containing amine groups and bis(chloropropyl)tetramethyl disiloxane; obtaining P / N / S / Si quaternary modified boron nitride flame retardant by substitution reaction of Cl groups of P / N / S / Si quaternary flame-retardant material and hydroxylated boron nitride; the present application enables the power cable to maintain good flame retardancy under long-term humid heat aging conditions.

Description

Technical Field

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

[0002] Power cables are cables used to transmit and distribute electrical energy. They are commonly used in urban underground power grids, power plant lead-out lines, internal power supply for industrial and mining enterprises, and underwater power transmission lines across rivers and seas.

[0003] Traditional cables often use a single flame retardant system (such as halogen or phosphorus-based flame retardants). Although this can delay combustion to some extent, it has the following problems: single organic flame retardants have low flame retardant efficiency, and inorganic flame retardants have poor interfacial bonding with the polymer matrix, which will also affect the uniformity of the flame retardant material; and some flame retardants are prone to hydrolysis in humid and hot environments, which will affect the overall flame retardant performance of the power cable. Summary of the Invention

[0004] The purpose of this invention is to provide a fire-fighting special double flame-retardant power cable and its preparation method. The technical problems solved by this invention are: single organic flame retardants have low flame retardant efficiency, inorganic flame retardants have poor interfacial bonding force with polymer matrix, which will also affect the uniformity of flame retardant materials; and some flame retardants are prone to hydrolysis in humid and hot environments.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A fire-fighting special double flame-retardant power cable includes, from the inside out, a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath;

[0007] The polyethylene flame-retardant outer sheath is prepared by mixing P / N / S / Si quaternary modified boron nitride flame retardant and linear low-density polyethylene in a mixer, heating and melting, and then extruding.

[0008] As a further aspect of the present invention: the polyethylene flame-retardant outer sheath is prepared from a P / N / S / Si quaternary modified boron nitride flame retardant, comprising:

[0009] A quaternary flame-retardant material of P / N / S / Si was prepared by modifying DOPO with three flame-retardant elements containing amine groups (P / N / S) and reacting it with bis(chloropropyl)tetramethyldisiloxane through a substitution reaction.

[0010] By substituting the Cl group of the P / N / S / Si quaternary flame retardant material with hydroxylated boron nitride, a P / N / S / Si quaternary modified boron nitride flame retardant is obtained.

[0011] As a further aspect of the present invention: the specific preparation process of the P / N / S / Si quaternary flame retardant material is as follows:

[0012] DOPO, bis(chloropropyl)tetramethyldisiloxane, and chloroform were modified with three flame-retardant elements containing amine groups (P / N / S) and mixed. Nitrogen gas was introduced for protection, and the mixture was stirred for 20-40 minutes at a temperature of 0-5℃ to obtain a quaternary flame-retardant material of P / N / S / Si.

[0013] As a further aspect of the present invention: the ratio of DOPO modified with three flame-retardant elements containing amine groups (P / N / S), bis(chloropropyl)tetramethyldisiloxane, and chloroform is 0.1 mol: 0.10 mol: 150-250 mL.

[0014] As a further aspect of the present invention, the preparation process of DOPO modified with three flame-retardant elements (P, N, and S) containing amine groups is as follows:

[0015] Under ice bath conditions, DOPO was mixed and dissolved with dichloromethane, then triethylamine and 2-aminobenzothiazole were added and stirred. Carbon tetrachloride was then added dropwise to the reaction system, the reaction temperature was controlled at 10-15℃, and the reaction was carried out for 12-15 hours to obtain DOPO modified with three flame-retardant elements, P, N, and S, containing amine groups.

[0016] As a further embodiment of the present invention: the mass ratio of DOPO, dichloromethane, triethylamine, 2-aminobenzothiazole, and carbon tetrachloride is 22.68:100-150:9-11:15.20:15-17.

[0017] As a further aspect of the present invention: the specific preparation process of the P / N / S / Si quaternary modified boron nitride flame retardant includes:

[0018] Hydroxylated boron nitride, a P / N / S / Si quaternary flame retardant, potassium hydroxide, and N,N-dimethylformamide were added to a reaction vessel and reacted at 70-75℃ for 5-8 hours. After the reaction was completed, a P / N / S / Si quaternary modified boron nitride flame retardant was obtained.

[0019] As a further embodiment of the present invention: the molar ratio of hydroxylated boron nitride, P / N / S / Si quaternary flame retardant material, potassium hydroxide and N,N-dimethylformamide is 0.1 mol: 0.1 mol: 6-10 g: 200-400 mL.

[0020] As a further aspect of the present invention: the mass ratio of P / N / S / Si quaternary modified boron nitride flame retardant to linear low-density polyethylene is 100:5-12.

[0021] A method for preparing a fire-fighting-specific double flame-retardant power cable, the method being used to prepare the aforementioned power cable, the method comprising:

[0022] From the inside out, the cable consists of a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath made from the aforementioned P / N / S / Si quaternary modified boron nitride flame retardant; thus, a fire-fighting special double flame-retardant power cable is obtained.

[0023] The beneficial effects of this invention are:

[0024] This invention combines four elements (P / N / S / Si) with hydroxylated boron nitride, i.e., organic and inorganic flame retardant materials, to form a multi-dimensional flame retardant system. Specifically, the flame retardant properties are as follows: phosphorus (P) promotes char layer formation and isolates heat and oxygen; nitrogen (N) releases inert gas to dilute combustible gases; sulfur (S) catalyzes char layer densification and inhibits free radical chain reactions; silicon (Si) enhances the thermal stability of the char layer; and boron nitride (BN) improves thermal conductivity and delays thermal degradation. Through the synergistic effect of these elements, the flame retardant performance of the cable outer sheath can be effectively improved. Furthermore, the quaternary flame retardant material of P / N / S / Si can effectively solve the problem of DOPO's high molecular polarity, poor compatibility with polyethylene, and easy migration or precipitation during long-term use.

[0025] Furthermore, boron nitride can induce polyethylene crystallization, refine polyethylene grains, and improve the crystallinity of the composite material. This results in a more compact molecular arrangement in the polyethylene outer sheath, making it difficult for oxygen to penetrate and thus better promoting the flame retardant properties of polyethylene. Additionally, boron nitride can rapidly disperse heat, suppressing localized overheating and allowing the outer sheath to maintain structural integrity at high temperatures. Through the substitution reaction of Cl groups and hydroxyl groups, chemical bonding between P / N / S / Si flame retardants and boron nitride is achieved, avoiding interface defects caused by physical blending. After modification, boron nitride is uniformly dispersed in the polyethylene matrix, which not only improves the tensile strength of the outer sheath but also makes the flame retardancy more uniform.

[0026] It also includes: combining the four elements P / N / S / Si with hydroxylated boron nitride to give it excellent hydrolysis resistance, making the flame retardant stable in humid environments, and also promoting the water resistance of the outer sheath of polyethylene cables, so that the power cables can maintain good flame retardancy even under long-term humid heat aging conditions. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with 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 skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0028] Example 1

[0029] This invention provides a fire-fighting special double flame-retardant power cable, which includes, from the inside out, a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath.

[0030] The preparation process of the polyethylene flame-retardant outer sheath includes the following steps:

[0031] Step 1: Modify DOPO with three flame-retardant elements containing amine groups (P / N / S) and react it with bis(chloropropyl)tetramethyldisiloxane to prepare a quaternary flame-retardant material of P / N / S / Si.

[0032] In step 1, the specific preparation process of the P / N / S / Si quaternary flame retardant material includes:

[0033] DOPO, bis(chloropropyl)tetramethyldisiloxane, and chloroform were modified with three flame-retardant elements containing amine groups (P / N / S) and mixed. Nitrogen gas was introduced for protection. The mixture was stirred for 20 minutes at a speed of 200 r / min and a temperature of 0℃. The chloroform was then removed by vacuum distillation at 38℃ using a rotary evaporator to obtain a quaternary flame-retardant material of P / N / S / Si.

[0034] The ratio of DOPO modified with three flame-retardant elements containing amine groups (P / N / S), bis(chloropropyl)tetramethyldisiloxane, and chloroform is 0.1 mol: 0.10 mol: 150 mL.

[0035] More specifically, the preparation process of DOPO modified with P / N / S flame-retardant elements containing amine groups is as follows:

[0036] Under ice bath conditions, DOPO was dissolved in dichloromethane, then triethylamine and 2-aminobenzothiazole were added and stirred. Carbon tetrachloride was then added dropwise to the reaction system, and the reaction temperature was controlled at 10°C. The reaction was carried out for 12-15 hours, and the filtrate was collected by filtration. The filtrate was then evaporated at 80°C in a rotary evaporator until the solution became viscous. Saturated NaHCO3 solution and acetone were added, and the mixture was stirred until solid particles precipitated. The mixture was then filtered, washed with deionized water and ethanol until the filter cake was white, and dried at 120°C for 12 hours to obtain DOPO modified with three flame-retardant elements (P, N, and S) containing amine groups.

[0037] The mass ratio of DOPO, dichloromethane, triethylamine, 2-aminobenzothiazole, and carbon tetrachloride was 22.68:100:9:15.20:15.

[0038] Step 2: The Cl group of the P / N / S / Si quaternary flame retardant material is reacted with hydroxylated boron nitride through a substitution reaction to obtain the P / N / S / Si quaternary modified boron nitride flame retardant;

[0039] In step 2, the specific preparation process of the P / N / S / Si quaternary modified boron nitride flame retardant includes:

[0040] Hydroxylated boron nitride, a P / N / S / Si quaternary flame retardant, potassium hydroxide, and N,N-dimethylformamide were added to a reaction vessel and reacted at 70°C for 5 hours. After the reaction was completed, the mixture was cooled to room temperature, transferred to a centrifuge tube, and centrifuged at 8000 rpm for 15 minutes to collect the solid product. The product was washed three times with anhydrous ethanol and deionized water to obtain the P / N / S / Si quaternary modified boron nitride flame retardant.

[0041] The molar ratio of hydroxylated boron nitride, P / N / S / Si quaternary flame retardant material, potassium hydroxide and N,N-dimethylformamide is 0.1mol:0.1mol:6g:200mL.

[0042] Step 3: Mix P / N / S / Si quaternary modified boron nitride flame retardant and linear low-density polyethylene in a mixer, heat and melt, and extrude to obtain a polyethylene flame-retardant outer protective layer.

[0043] The mass ratio of P / N / S / Si quaternary modified boron nitride flame retardant to linear low-density polyethylene is 100:5.

[0044] This invention also provides a method for preparing a fire-fighting dual flame-retardant power cable, comprising the following steps:

[0045] From the inside out, the cable consists of a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath made from the aforementioned P / N / S / Si quaternary modified boron nitride flame retardant; thus, a fire-fighting special double flame-retardant power cable is obtained.

[0046] Example 2

[0047] This invention provides a fire-fighting special double flame-retardant power cable, which includes, from the inside out, a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath.

[0048] The preparation process of the polyethylene flame-retardant outer sheath includes the following steps:

[0049] Step 1: Modify DOPO with three flame-retardant elements containing amine groups (P / N / S) and react it with bis(chloropropyl)tetramethyldisiloxane to prepare a quaternary flame-retardant material of P / N / S / Si.

[0050] In step 1, the specific preparation process of the P / N / S / Si quaternary flame retardant material includes:

[0051] DOPO, bis(chloropropyl)tetramethyldisiloxane, and chloroform were modified with three flame-retardant elements containing amine groups (P / N / S) and mixed. Nitrogen gas was introduced for protection. The mixture was stirred for 30 minutes at a speed of 250 r / min and a temperature of 2℃. The chloroform was then removed by vacuum distillation at 38℃ using a rotary evaporator to obtain a quaternary flame-retardant material of P / N / S / Si.

[0052] The ratio of DOPO modified with three flame-retardant elements containing amine groups (P / N / S), bis(chloropropyl)tetramethyldisiloxane, and chloroform is 0.1 mol: 0.10 mol: 200 mL.

[0053] More specifically, the preparation process of DOPO modified with P / N / S flame-retardant elements containing amine groups is as follows:

[0054] Under ice bath conditions, DOPO was dissolved in dichloromethane, then triethylamine and 2-aminobenzothiazole were added and stirred. Carbon tetrachloride was then added dropwise to the reaction system, the reaction temperature was controlled at 12℃, and the reaction was carried out for 13 hours. The filtrate was collected by filtration. The filtrate was evaporated at 80℃ in a rotary evaporator until the solution became viscous. Saturated NaHCO3 solution and acetone were added, and the mixture was stirred until solid particles precipitated. The mixture was then filtered, washed with deionized water and ethanol until the filter cake was white, and dried at 120℃ for 12 hours to obtain DOPO modified with three flame-retardant elements (P, N, and S) containing amine groups.

[0055] The mass ratio of DOPO, dichloromethane, triethylamine, 2-aminobenzothiazole, and carbon tetrachloride was 22.68:120:10:15.20:16.

[0056] Step 2: The Cl group of the P / N / S / Si quaternary flame retardant material is reacted with hydroxylated boron nitride through a substitution reaction to obtain the P / N / S / Si quaternary modified boron nitride flame retardant;

[0057] In step 2, the specific preparation process of the P / N / S / Si quaternary modified boron nitride flame retardant includes:

[0058] Hydroxylated boron nitride, a P / N / S / Si quaternary flame retardant, potassium hydroxide, and N,N-dimethylformamide were added to a reaction vessel and reacted at 72°C for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, transferred to a centrifuge tube, and centrifuged at 9000 rpm for 18 minutes to collect the solid product. The product was washed three times with anhydrous ethanol and deionized water to obtain the P / N / S / Si quaternary modified boron nitride flame retardant.

[0059] The molar ratio of hydroxylated boron nitride, P / N / S / Si quaternary flame retardant material, potassium hydroxide and N,N-dimethylformamide is 0.1mol:0.1mol:8g:300mL.

[0060] Step 3: Mix P / N / S / Si quaternary modified boron nitride flame retardant and linear low-density polyethylene in a mixer, heat and melt, and extrude to obtain a polyethylene flame-retardant outer protective layer.

[0061] The mass ratio of P / N / S / Si quaternary modified boron nitride flame retardant to linear low-density polyethylene is 100:8.

[0062] This invention also provides a method for preparing a fire-fighting dual flame-retardant power cable, comprising the following steps:

[0063] From the inside out, the cable consists of a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath made from the aforementioned P / N / S / Si quaternary modified boron nitride flame retardant; thus, a fire-fighting special double flame-retardant power cable is obtained.

[0064] Example 3

[0065] This invention provides a fire-fighting special double flame-retardant power cable, which includes, from the inside out, a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath.

[0066] The preparation process of the polyethylene flame-retardant outer sheath includes the following steps:

[0067] Step 1: Modify DOPO with three flame-retardant elements containing amine groups (P / N / S) and react it with bis(chloropropyl)tetramethyldisiloxane to prepare a quaternary flame-retardant material of P / N / S / Si.

[0068] In step 1, the specific preparation process of the P / N / S / Si quaternary flame retardant material includes:

[0069] DOPO, bis(chloropropyl)tetramethyldisiloxane, and chloroform were modified with three flame-retardant elements containing amine groups (P / N / S) and mixed. Nitrogen gas was introduced for protection. The mixture was stirred for 40 minutes at a speed of 300 r / min and a temperature of 5℃. The chloroform was then removed by vacuum distillation at 38℃ using a rotary evaporator to obtain a quaternary flame-retardant material of P / N / S / Si.

[0070] The ratio of DOPO modified with three flame-retardant elements containing amine groups (P / N / S), bis(chloropropyl)tetramethyldisiloxane, and chloroform is 0.1 mol: 0.10 mol: 250 mL.

[0071] More specifically, the preparation process of DOPO modified with P / N / S flame-retardant elements containing amine groups is as follows:

[0072] Under ice bath conditions, DOPO was dissolved in dichloromethane, then triethylamine and 2-aminobenzothiazole were added and stirred. Carbon tetrachloride was then added dropwise to the reaction system, the reaction temperature was controlled at 15℃, and the reaction was carried out for 15 hours. The filtrate was collected by filtration. The filtrate was evaporated at 80℃ in a rotary evaporator until the solution became viscous. Saturated NaHCO3 solution and acetone were added, and the mixture was stirred until solid particles precipitated. The mixture was then filtered, washed with deionized water and ethanol until the filter cake was white, and dried at 120℃ for 12 hours to obtain DOPO modified with three flame-retardant elements (P, N, and S) containing amine groups.

[0073] The mass ratio of DOPO, dichloromethane, triethylamine, 2-aminobenzothiazole, and carbon tetrachloride was 22.68:150:11:15.20:17.

[0074] Step 2: The Cl group of the P / N / S / Si quaternary flame retardant material is reacted with hydroxylated boron nitride through a substitution reaction to obtain the P / N / S / Si quaternary modified boron nitride flame retardant;

[0075] In step 2, the specific preparation process of the P / N / S / Si quaternary modified boron nitride flame retardant includes:

[0076] Hydroxylated boron nitride, a P / N / S / Si quaternary flame retardant, potassium hydroxide, and N,N-dimethylformamide were added to a reaction vessel and reacted at 75°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature, transferred to a centrifuge tube, and centrifuged at 10,000 rpm for 20 minutes to collect the solid product. The product was washed three times with anhydrous ethanol and deionized water to obtain the P / N / S / Si quaternary modified boron nitride flame retardant.

[0077] The molar ratio of hydroxylated boron nitride, P / N / S / Si quaternary flame retardant material, potassium hydroxide and N,N-dimethylformamide is 0.1mol:0.1mol:10g:400mL.

[0078] Step 3: Mix P / N / S / Si quaternary modified boron nitride flame retardant and linear low-density polyethylene in a mixer, heat and melt, and extrude to obtain a polyethylene flame-retardant outer protective layer.

[0079] The mass ratio of P / N / S / Si quaternary modified boron nitride flame retardant to linear low-density polyethylene is 100:12.

[0080] This invention also provides a method for preparing a fire-fighting dual flame-retardant power cable, comprising the following steps:

[0081] From the inside out, the cable consists of a circular conductor, an insulating shielding layer, a metal layer, a metal armor layer, and a polyethylene flame-retardant outer sheath made from the aforementioned P / N / S / Si quaternary modified boron nitride flame retardant; thus, a fire-fighting special double flame-retardant power cable is obtained.

[0082] Comparative Example 1

[0083] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 is a pure linear low-density polyethylene (LLDPE) outer sheath cable without the addition of P / N / S / Si quaternary modified boron nitride flame retardant.

[0084] Comparative Example 2

[0085] Comparative Example 2 uses the polyethylene insulated power cable disclosed in Example 1 of Chinese Patent Publication No. CN 108417301 B.

[0086] The performance of the outer protective layer of Examples 1-3 and Comparative Examples 1-2 was tested, and the test results are shown in the table below. The performance tests included limiting oxygen index LO I (test standard GB / T 2408-2021), tensile strength (test standard GB / T 1040-2018), and resistance to damp heat aging (test standard GB / T2951.12-2008).

[0087]

[0088] As can be seen from the table above, the cable outer sheath prepared by the present invention using P / N / S / Si quaternary modified boron nitride flame retardant has the advantages of excellent flame retardancy, resistance to damp heat aging, and tensile strength.

[0089] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A fire service special double-flame-retardant power cable, characterized by, The power cable comprises, from inside to outside, a circular conductor, an insulating shielding layer, a metal layer, a metal armored layer, and a polyethylene flame-retardant outer protective layer. The polyethylene flame-retardant outer protective layer is prepared by mixing P / N / S / Si quaternary modified boron nitride flame retardant and linear low-density polyethylene in a mixing mill, heating and melting, and extruding. The preparation of the P / N / S / Si quaternary modified boron nitride flame retardant comprises: The P / N / S / Si quaternary flame-retardant material is prepared by substituting reaction of P / N / S three flame-retardant element modified DOPO containing amine groups and bis(chloropropyl)tetramethyl disiloxane. The P / N / S / Si quaternary modified boron nitride flame retardant is obtained by substituting reaction of Cl groups of the P / N / S / Si quaternary flame-retardant material and hydroxylated boron nitride. The P / N / S / Si quaternary flame-retardant material is prepared by mixing P / N / S three flame-retardant element modified DOPO containing amine groups, bis(chloropropyl)tetramethyl disiloxane, and chloroform, and then stirring for 20-40 min under the protection of nitrogen at a temperature of 0-5℃. The amount ratio of P / N / S three flame-retardant element modified DOPO containing amine groups, bis(chloropropyl)tetramethyl disiloxane, and chloroform is 0.1 mol:0.10 mol:150-250 mL. The preparation process of P / N / S three flame-retardant element modified DOPO containing amine groups comprises:

2. A fire-fighting special double flame-retardant power cable according to claim 1, characterized in that, Under ice bath conditions, DOPO is mixed and dissolved in dichloromethane, and then triethylamine and 2-amino benzothiazole are added and stirred, and carbon tetrachloride is added dropwise into the reaction system, the reaction temperature is controlled at 10-15℃, and the reaction is carried out for 12-15 h to obtain P / N / S three flame-retardant element modified DOPO containing amine groups. The mass ratio of DOPO, dichloromethane, triethylamine, 2-amino benzothiazole, and carbon tetrachloride is 22.68:100-150:9-11:15.20:15-17.

3. A fire-fighting special double flame-retardant power cable according to claim 2, characterized in that, The preparation process of the P / N / S / Si quaternary modified boron nitride flame retardant comprises:

4. A fire-fighting special double flame-retardant power cable according to claim 1, characterized in that, Hydroxylated boron nitride, P / N / S / Si quaternary flame-retardant material, potassium hydroxide, and N,N-dimethylformamide are added into a reaction kettle, and the reaction is carried out for 5-8 h at a temperature of 70-75℃, and then the P / N / S / Si quaternary modified boron nitride flame retardant is obtained after the reaction is completed. The molar ratio of hydroxylated boron nitride, P / N / S / Si quaternary flame-retardant material, potassium hydroxide, and N,N-dimethylformamide is 0.1 mol:0.1 mol:6-10 g:200-400 mL.

5. A fire fighting special double flame retardant power cable as claimed in claim 3, characterized in that, The mass ratio of the P / N / S / Si quaternary modified boron nitride flame retardant and linear low-density polyethylene is 100:5-12.

6. A fire fighting special double flame retardant power cable as claimed in claim 1, characterized in that, The method is used for preparing the power cable of any one of claims 1-5.

7. A process for the preparation of a fire service special double flame-retardant power cable, characterized by, The power cable comprises, from inside to outside, a circular conductor, an insulating shielding layer, a metal layer, a metal armored layer, and a polyethylene flame-retardant outer protective layer prepared from the P / N / S / Si quaternary modified boron nitride flame retardant, thereby obtaining a fire-fighting special double-flame-retardant power cable. ​

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