Flame-retardant auxiliary agent, preparation method thereof, flame-retardant cable material containing flame-retardant auxiliary agent and preparation method of flame-retardant cable material

Abstract

The invention belongs to the field of cable materials, and particularly discloses a flame-retardant auxiliary agent and a preparation method thereof, a flame-retardant cable material containing the flame-retardant auxiliary agent and a preparation method of the flame-retardant cable material. The compound containing phosphate, amino, hydroxyl and siloxane structures is used as the flame-retardant synergist of the cable material, the flame-retardant synergist cooperates with the inorganic flame retardant, the advantages of an acid source, a gas source and a carbon source are combined into a whole, the flame-retardant performance and the low-smoke effect of the cable material are greatly improved, and the cable material is suitable for industrial production. The mechanical property and the processability of the cable material are not obviously reduced, so that the cable material has the characteristics of high oxygen index, low smoke, no halogen and good mechanical property and processability, and has wide application prospects in the fields of buildings, industries and the like.

Description

Technical Field

[0001] The present invention belongs to the field of cable materials, and in particular relates to a flame retardant additive and a preparation method thereof, a flame retardant cable material containing the flame retardant additive and a preparation method thereof. Background Art

[0002] With the development of modern industry, the safety, environmental friendliness, and flame retardancy requirements for wires and cables are increasing. During testing, the oxygen index is often used to measure the flame retardancy of wires and cables. The oxygen index refers to the minimum oxygen concentration required for a material to burn with a flame in an oxygen-nitrogen mixture under specified conditions. Therefore, this value can be used to quickly determine the flame retardancy of a material.

[0003] Although traditional halogen-containing flame-retardant cables have a high oxygen index and good flame retardant properties, they produce large amounts of toxic smoke and corrosive gases when burned, causing serious harm to the environment and human health. At present, the main halogen-free cable materials on the market use metal hydroxides as the main halogen-free flame retardants, and at the same time add various types of auxiliary flame retardants such as phosphorus-containing compounds, nitrogen-containing compounds, and silicon-containing compounds. Compared with halogen-containing flame retardants, this strategy has the advantages of not producing toxic gases and being environmentally friendly and green, but the degree of improvement in flame retardant properties is limited. In order to further meet the flame retardant requirements, it is conventional to increase the filling ratio of metal hydroxide-based inorganic flame retardants, but this often leads to a decrease in the mechanical properties and processing properties of the cable material, resulting in another adverse effect.

[0004] Therefore, developing a high oxygen index, low smoke, halogen-free flame retardant cable material with good flame retardant properties, mechanical properties, and processing properties has become an important research direction in the current cable material field. Summary of the Invention

[0005] In response to the problem in the above-mentioned prior art that the flame retardant properties, mechanical properties and processing properties of cable materials cannot be taken into account at the same time, the present invention will provide a flame retardant additive and a preparation method thereof, a flame retardant cable material containing the same and a preparation method thereof.

[0006] To achieve the above objectives, the following technical solutions are specifically included: In a first aspect, the present invention provides a flame retardant additive, the chemical structure of which is shown in Formula I below: Formula I.

[0007] The flame retardant auxiliary agent of the present invention has phosphate, amino, hydroxyl and siloxane structures and has a good flame retardant assisting effect in the material.

[0008] In a second aspect, the present invention provides a method for preparing the flame retardant additive, comprising the following steps: S1, mixing (3-hydroxypropyl)-dimethyl phosphonate, ammonium chloride, sodium cyanoborohydride and a solvent, performing a first reaction, and obtaining a first intermediate product through distillation, extraction and drying; S2, mixing trimethoxysilane, 3-bromo-1,2-propylene glycol, a catalyst, and toluene, performing a second reaction, filtering, and purifying to obtain a second intermediate product; S3. Mix the first intermediate product, the second intermediate product, potassium carbonate and N,N-dimethylformamide, carry out a third reaction, and obtain the flame retardant auxiliary agent through filtering, extraction, drying and purification.

[0009] Preferably, in step S1, the first reaction time is 12-14 hours, the distillation is reduced pressure distillation, and the extraction solvent is dichloromethane.

[0010] Preferably, in step S1, the molar ratio of (3-hydroxypropyl)-dimethyl phosphonate, ammonium chloride and sodium cyanoborohydride is 1:(1-8):(0.9-2).

[0011] Preferably, in step S2, the time of the second reaction is 6-8 hours, the temperature of the second reaction is 60-90° C., the atmosphere of the second reaction is an inert gas atmosphere, and the purification is performed by chromatography column.

[0012] Preferably, in step S2, the catalyst comprises platinum-carbon.

[0013] Preferably, based on the total mass of trimethoxysilane and 3-bromo-1,2-propanediol, the mass proportion of the catalyst is 0.1%-2%.

[0014] Preferably, in step S2, the molar ratio of trimethoxysilane to 3-bromo-1,2-propylene glycol is 1:(0.8-1.2).

[0015] Preferably, in step S3, the time of the third reaction is 12-18 hours, the temperature of the third reaction is 60-90° C., the atmosphere of the third reaction is an inert gas atmosphere, the extraction solvent is ethyl acetate, and the purification is performed by chromatography column.

[0016] Preferably, in step S3, the molar ratio of the first intermediate product, the second intermediate product and potassium carbonate is 1:(0.9-1.2):(2-6).

[0017] In a third aspect, the present invention provides a flame-retardant cable material comprising the following components in parts by weight: 10-40 parts of ethylene-vinyl acetate copolymer, 5-30 parts of polyethylene resin, 2-10 parts of EPDM rubber, 50-60 parts of inorganic flame retardant, 1-10 parts of flame retardant synergist, 0.5-1 parts of silane coupling agent, and 0-10 parts of other additives; the flame retardant synergist includes the flame retardant additive.

[0018] In the cable material of the present invention, a compound containing phosphate, amino, hydroxyl and siloxane structures is used as a flame retardant synergist for the cable material. When the cable material exerts its flame retardant effect, the inorganic flame retardant in the cable material mainly exerts its effect in the gas phase and the condensed phase, and the flame retardant synergist enhances the flame retardant effect through the expansion flame retardant mechanism. The inorganic flame retardant and the flame retardant synergist are combined to form a multi-level protection, which synergistically improves the flame retardant performance of the cable material. The phosphate structure in the flame retardant synergist will form polyphosphoric acid after being heated, and the acidic environment will catalyze the dehydration of the matrix resin to form a dense carbon layer; the non-combustible gas generated by the amino structure and the water vapor generated by the combustion and decomposition of the inorganic flame retardant will jointly make the carbon layer The layer expands into a porous structure, and the silicon film formed after the siloxane structure is heated can isolate heat and oxygen while suppressing the escape of smoke. In this way, the advantages of acid source, gas source and carbon source are combined into one, and the flame retardant performance and low smoke effect of the cable material are greatly improved. Even if a small amount of inorganic flame retardant is added to the cable material, the flame retardant synergist can work together with a small amount of inorganic flame retardant to efficiently improve the oxygen index of the cable material without significantly reducing the mechanical properties and processing properties of the cable material. The cable material has the characteristics of high oxygen index, low smoke, halogen-free and good mechanical properties and processing properties, which makes it have broad application prospects in construction, industry and other fields.

[0019] Preferably, the flame retardant cable material comprises the following components in parts by weight: 15-30 parts of ethylene-vinyl acetate copolymer, 10-20 parts of polyethylene resin, 2-8 parts of EPDM rubber, 51-57 parts of inorganic flame retardant, 1-10 parts of flame retardant synergist, 0.5-1 parts of silane coupling agent, and 0.25-1 parts of other additives.

[0020] Preferably, in the flame-retardant cable material, the mass percentage of the inorganic flame retardant is 40%-54%, more preferably 48%-53.5%.

[0021] Preferably, in the flame retardant cable material, the mass percentage of the flame retardant synergist is 1%-10%, more preferably 1.5%-8%.

[0022] Preferably, the mass ratio of the inorganic flame retardant to the flame retardant synergist is 1:(0.03-0.2). Within this mass ratio range, the inorganic flame retardant and the flame retardant synergist can better cooperate with each other, further improving the flame retardancy of the cable material without significantly degrading the mechanical properties and processing performance of the cable material.

[0023] Preferably, the mass percentage of the inorganic flame retardant in the flame retardant cable material is 40%-55%. The cable material of the present invention can maintain a high oxygen index even when the inorganic flame retardant accounts for a relatively low proportion.

[0024] Preferably, the inorganic flame retardant includes at least one of aluminum hydroxide or magnesium hydroxide.

[0025] More preferably, the inorganic flame retardant is aluminum hydroxide and magnesium hydroxide. Aluminum hydroxide and magnesium hydroxide are compounded to broaden the applicable temperature range because they have different thermal decomposition temperatures.

[0026] Preferably, the D50 of the inorganic flame retardant is less than 3 μm.

[0027] Preferably, the mass percentage of vinyl acetate (VA) in the ethylene-vinyl acetate copolymer (EVA) is 18%-28%. A VA content within the above range is beneficial for improving the mechanical properties and oxygen index of the flame-retardant cable material.

[0028] Preferably, the polyethylene resin includes at least one of linear low-density polyethylene, low-density polyethylene, medium-density polyethylene or high-density polyethylene.

[0029] Preferably, the polyethylene resin has a melt index of 5-20 g / 10 min at 190° C. and a load of 2.16 kg.

[0030] Preferably, the Mooney viscosity of the EPDM rubber at 125°C is 20-50. EPDM rubber provides excellent flexibility and high-temperature resistance to the cable material. Furthermore, the presence of a silane coupling agent in the cable material can modify the EPDM rubber, improving its compatibility with EVA and PE resin matrices, further improving the flexibility and high-temperature resistance of the cable material.

[0031] Preferably, the silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, vinyltriethoxysilane, or γ-methacryloyloxypropyltrimethoxysilane. On the one hand, the silane coupling agent can modify EPDM rubber, improving its compatibility with EVA and PE resin matrices, further improving the cable material's flexibility and high-temperature resistance. On the other hand, the alkoxy groups of the silane coupling agent, after hydrolysis, undergo a condensation reaction with the hydroxyl groups on the surface of the inorganic flame retardant to form a chemical bond. The amino, vinyl, or methacryloxy groups at the other end then react chemically with the resin matrix. The silane coupling agent acts as a "bridge," improving the interfacial compatibility between the resin matrix and the inorganic flame retardant, making the inorganic flame retardant more evenly dispersed, thereby enhancing the mechanical and flame-retardant properties of the cable material.

[0032] Preferably, the other additives include the following components in parts by weight: 0.5-2 parts of antioxidant, 1-2 parts of silicone masterbatch, and 0.25-1.5 parts of lubricant.

[0033] Further preferably, the silicone masterbatch can be an EVA-based silicone masterbatch with a silicone content of 20%-40%.

[0034] Further preferably, the lubricant includes at least one of PE wax or zinc stearate.

[0035] Further preferably, the antioxidant includes at least one of tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]pentaerythritol ester, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, dilauryl thiodipropionate, and distearyl thiodipropionate.

[0036] In a fourth aspect, the present invention provides a method for preparing the flame retardant cable material, comprising the steps of: subjecting the raw materials to mixing, banburying, melt extrusion, granulation and drying in sequence to obtain the flame retardant cable material. Preferably, the banburying temperature is 140° C.-170° C., the speed during banburying is 10-100 rpm, and the banburying time is 15-20 minutes.

[0037] Preferably, in the melt extrusion, the temperatures of the extruder from the feed port to the discharge port are: 90-110°C in zone 1, 110-140°C in zone 2, 130-150°C in zone 3, 140-160°C in zone 4, and 150-170°C in zone 5, the material temperature is 150-170°C, the die head temperature is 150-170°C, the extrusion pressure is 10-20 MPa, and the extrusion frequency is 15-25 Hz.

[0038] Compared with the prior art, the present invention has the following beneficial effects: the present invention uses a compound containing a phosphate, amino, hydroxyl, and siloxane structure as a flame retardant synergist for cable materials. This flame retardant synergist works synergistically with an inorganic flame retardant to achieve a synergistic combination of the advantages of an acid source, a gas source, and a carbon source. The flame retardant performance and low smoke effect of the cable material are significantly improved without significantly reducing the mechanical and processing properties of the cable material. This allows the cable material to simultaneously have a high oxygen index, low smoke, and be halogen-free, as well as good mechanical and processing properties, giving it broad application prospects in fields such as construction and industry. In addition, the preparation method of the cable material of the present invention is simple and highly operable, providing the possibility of large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the infrared spectrum of the flame retardant auxiliary agent of formula I of the present invention. DETAILED DESCRIPTION

[0040] To better illustrate the objectives, technical solutions, and advantages of the present invention, the present invention will be further described below with reference to specific examples. The experimental methods used in the examples and / or comparative examples are conventional methods unless otherwise specified; the materials and reagents used are commercially available unless otherwise specified.

[0041] Some raw material information: Ethylene-vinyl acetate copolymer: brand UL00628, manufacturer Lianhong New Materials, VA content 28%; Low-density polyethylene resin: brand LD605, manufacturer Yanshan Petrochemical, melt index is 6g / 10min.

[0042] Linear low-density polyethylene: brand 8916, manufacturer Maoming Petrochemical, melt index is 16g / 10min.

[0043] EPDM rubber: brand 4725P, manufacturer DowDuPont, Mooney viscosity 25.

[0044] Silicone masterbatch: EVA-based silicone masterbatch with a silicone content of 20%-40%.

[0045] Example 1 This embodiment provides a flame retardant auxiliary agent of formula I, and its preparation method comprises the following steps: S1. Mix (3-hydroxypropyl)-dimethyl phosphonate, ammonium chloride, sodium cyanoborohydride, and a methanol aqueous solution (methanol to water volume ratio of 4:1), use acetic acid to maintain the solution in a neutral environment, react at room temperature for 14 hours, distill under reduced pressure to remove methanol, extract with dichloromethane to remove water, and dry to obtain a first intermediate product; wherein the molar ratio of (3-hydroxypropyl)-dimethyl phosphonate, ammonium chloride, and sodium cyanoborohydride is 1:5:1.5, and the concentration of (3-hydroxypropyl)-dimethyl phosphonate in the methanol aqueous solution is 1 mol / L; the chemical structure of the first intermediate product is as follows: Formula II; S2. Trimethoxysilane, 3-bromo-1,2-propylene glycol, a catalyst, and anhydrous toluene were mixed, reacted at 80° C. under nitrogen protection for 6 h, the catalyst was filtered, and purified by chromatography to obtain a second intermediate product; wherein the molar ratio of trimethoxysilane to 3-bromo-1,2-propylene glycol was 1:1, the concentration of trimethoxysilane in toluene was 1 mol / L, and the catalyst was platinum carbon in an amount of 1 wt% of the substrate mass; the chemical structure of the second intermediate product is as follows: Formula III; Step S3: Mix the first intermediate product, the second intermediate product, potassium carbonate and anhydrous DMF, react at 80°C under nitrogen protection for 18 hours, cool to room temperature, filter, extract and wash with ethyl acetate, dry, and purify by chromatography to obtain the final flame retardant additive of formula I; wherein the molar ratio of the first intermediate product, the second intermediate product and potassium carbonate is 1:1.05:4, and the concentration of the first intermediate product in anhydrous DMF is 1 mol / L.

[0046] The flame retardant auxiliary agent of formula I obtained in this example is used as the flame retardant synergist in the flame retardant cable material of this example.

[0047] The present embodiment provides a flame-retardant cable material, which includes the following components in parts by weight: 30 parts of ethylene-vinyl acetate copolymer, 20 parts of low-density polyethylene, 5 parts of EPDM rubber, 38 parts of aluminum hydroxide, 19 parts of magnesium hydroxide, 2 parts of a flame retardant synergist, 0.6 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1.25 parts of a silicone masterbatch, 0.5 parts of γ-aminopropyltriethoxysilane, and 0.5 parts of PE wax.

[0048] The method for preparing a flame-retardant cable material in this embodiment includes the following steps: (1) Weigh the following raw material components in parts by weight: 30 parts of ethylene-vinyl acetate copolymer, 20 parts of low-density polyethylene, 5 parts of ethylene propylene diene monomer rubber, 38 parts of aluminum hydroxide, 19 parts of magnesium hydroxide, 2 parts of flame retardant synergist, 0.6 parts of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 1.25 parts of silicone masterbatch, 0.5 parts of γ-aminopropyltriethoxysilane, and 0.5 parts of PE wax; mix the weighed raw materials in order and put them into a mixing bin, lower the top bolt and pressurize the mixing bin at a temperature of 160°C and a speed of 50 rpm for 20 minutes. When the time is up, raise the top bolt and discharge the material to obtain a premix; (2) The premix obtained in step (1) is added to a twin-screw extruder for melt extrusion granulation, and the cable material is obtained after air cooling; wherein the temperature of the twin-screw extruder from the feed port to the discharge port is: 100°C in zone 1, 120°C in zone 2, 140°C in zone 3, 155°C in zone 4, and 160°C in zone 5, the material temperature is maintained at 165°C, the head temperature is maintained at 160°C, the extrusion pressure is controlled at 15 MPa, and the extrusion frequency is controlled at 20 Hz.

[0049] Example 2 Compared with Example 1, the difference is that the raw materials of a flame retardant cable material in this embodiment include the following components in parts by weight: 15 parts of ethylene-vinyl acetate copolymer (VA content is 28%), 15 parts of linear low-density polyethylene, 8 parts of EPDM rubber, 36 parts of aluminum hydroxide, 18 parts of magnesium hydroxide, 5 parts of flame retardant synergist (same as Example 1), 0.6 parts of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 0.6 parts of dilauryl thiodipropionate, 1.25 parts of silicone masterbatch, 1 part of vinyl triethoxysilane, and 0.25 parts of zinc stearate; the rest are the same.

[0050] Example 3 Compared with Example 1, the difference is that the raw materials of a flame retardant cable material in this embodiment include the following components in parts by weight: 30 parts of ethylene-vinyl acetate copolymer (VA content is 28%), 10 parts of low-density polyethylene, 2 parts of EPDM rubber, 34 parts of aluminum hydroxide, 17 parts of magnesium hydroxide, 8 parts of flame retardant synergist (same as Example 1), 1 part of tris(2,4-di-tert-butylphenyl) phosphite, 2 parts of silicone masterbatch, 0.8 parts of γ-methacryloyloxypropyltrimethoxysilane, 0.5 parts of PE wax, and 0.5 parts of zinc stearate; the rest are the same.

[0051] Example 4 Compared with Example 1, the difference is that this example contains 1 part of flame retardant synergist, and the rest is the same.

[0052] Example 5 Compared with Example 1, the difference is that the flame retardant synergist in this example is 5 parts, and the rest is the same.

[0053] Example 6 Compared with Example 1, the difference is that this example contains 10 parts of flame retardant synergist, and the rest is the same.

[0054] Example 7 Compared with Example 1, the difference is that the aluminum hydroxide in this embodiment is 57 parts and the magnesium hydroxide is 0 part, and the rest are the same.

[0055] Example 8 Compared with Example 1, the difference is that the aluminum hydroxide in this embodiment is 0 parts and the magnesium hydroxide is 57 parts, and the rest is the same.

[0056] Comparative Example 1 Compared with Example 1, the difference is that no flame retardant synergist is added in this comparative example, and the rest is the same.

[0057] Comparative Example 2 Compared with Example 2, the difference is that no EPDM rubber is added in this comparative example, and the rest is the same.

[0058] Comparative Example 3 Compared with Example 3, the difference is that in this comparative example, 8 parts by weight of the flame retardant synergist is replaced by 6 parts by weight of ammonium polyphosphate and 3 parts by weight of pentaerythritol, and the rest are the same.

[0059] Comparative Example 4 Compared with Example 1, the difference is that no flame retardant synergist is added in this comparative example, and the inorganic flame retardant is increased in proportion to 70 parts, and the rest is the same.

[0060] Comparative Example 5 Compared with Example 1, the difference is that no flame retardant synergist and inorganic flame retardant are added in this comparative example, and the rest are the same.

[0061] The amounts (parts by weight) of the components used in Examples 1-8 and Comparative Examples 1-5 are listed in Table 1.

[0062] Table 1 The flame-retardant cable materials obtained in the examples and comparative examples were injection molded into corresponding specimens for testing. The tensile strength and elongation at break were tested according to the GB / T 1040.3-2016 standard at a tensile speed of 250 mm / min; the limiting oxygen index was tested according to the GB / T 2406.2-2009 standard; and the smoke density was tested according to the GB / T 8323.2-2008 standard. The test results are shown in Table 2.

[0063] Table 2 Depend on Figure 1It can be seen that the infrared spectrum of the flame retardant additive of formula I is at 813.7 cm -1 There is a peak at 1038.6cm, indicating the existence of Si-O-Si symmetric stretching vibration; -1 The presence of a peak indicates the presence of CO stretching vibration; at 1200.3 cm -1 There is a peak at 3296.4cm, indicating the presence of P=O stretching vibration; -1 There is a broad peak at , which may be merged into one peak due to the simultaneous presence of OH and NH; thus, it can be seen that the flame retardant additive of formula I was successfully synthesized.

[0064] As can be seen from Table 2, by comparing Example 1 with Comparative Example 1, when the flame retardant additive of Formula I is used as a flame retardant synergist for the cable material, the oxygen index of the cable material can be significantly improved even if a relatively small amount of the flame retardant synergist is added. At the same time, it can be seen from the smoke density that the carbon layer and silicon film formed by heating effectively inhibit the overflow of smoke. And from the perspective of mechanical properties, there is no obvious decrease in the mechanical properties.

[0065] Comparing Example 2 with Comparative Example 2, it can be seen that Comparative Example 2 lacks EPDM rubber. While flame retardancy is minimal, mechanical properties, particularly elongation at break, are significantly reduced. EPDM rubber can improve the mechanical properties of cable materials. Furthermore, the inventors have experimentally verified that replacing it with synergists with other chemical structures, such as siloxanes, amino groups, and phosphates, fails to achieve similar results. For example, comparing Example 3 with Comparative Example 3, which uses a conventional ammonium polyphosphate and pentaerythritol blend as a flame retardant synergist for its cable material, reveals that both components do not achieve the same improvement in oxygen index as the flame retardant synergist of Formula I employed in the present invention, and mechanical properties are also affected to some extent.

[0066] In summary, it can be seen from Examples 1-3 that the cable material of the present invention contains a flame retardant synergist with a specific chemical structure, so that the cable material, on the basis of having good mechanical properties, can form a suitable expansion layer after the cable material is heated, thereby improving the flame retardant properties and obtaining a higher oxygen index and a lower smoke density; at the same time, by combining Examples 1-3 with Comparative Examples 4-5, it can be seen that the cable material can have better flame retardant properties than the cable material filled with only a high amount of inorganic flame retardant by adding a low amount of flame retardant synergist and a low amount of inorganic flame retardant, and significantly improve the oxygen index while maintaining good mechanical properties.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A flame retardant auxiliary agent, characterized in that: Its chemical structure is shown in the following formula I: Formula I.

2. A method for preparing the flame retardant auxiliary agent according to claim 1, characterized in that: The steps include: S1, mixing (3-hydroxypropyl)-dimethyl phosphonate, ammonium chloride, sodium cyanoborohydride and a solvent, performing a first reaction, and obtaining a first intermediate product through distillation, extraction and drying; S2, mixing trimethoxysilane, 3-bromo-1,2-propylene glycol, a catalyst, and toluene, performing a second reaction, filtering, and purifying to obtain a second intermediate product; S3. Mix the first intermediate product, the second intermediate product, potassium carbonate and N,N-dimethylformamide, carry out a third reaction, and obtain the flame retardant auxiliary agent through filtering, extraction, drying and purification.

3. The method for preparing a flame retardant auxiliary agent according to claim 2, wherein: Include at least one of the following: A. In step S1, the first reaction time is 12-14 h, the distillation is reduced pressure distillation, and the extraction solvent is dichloromethane; B. In step S2, the second reaction time is 6-8h, the second reaction temperature is 60-90°C, the second reaction atmosphere is an inert gas atmosphere, and the purification is performed by chromatography; C. In step S1, the molar ratio of (3-hydroxypropyl)-dimethyl phosphonate, ammonium chloride and sodium cyanoborohydride is 1:(1-8):(0.9-2); D. In step S3, the time of the third reaction is 12-18 hours, the temperature of the third reaction is 60-90° C., the atmosphere of the third reaction is an inert gas atmosphere, the solvent of the extraction is ethyl acetate, and the purification is performed by chromatography; E. In step S2, the catalyst includes platinum carbon; F. In step S2, the molar ratio of trimethoxysilane to 3-bromo-1,2-propylene glycol is 1:(0.8-1.2); G. In step S3, the molar ratio of the first intermediate product, the second intermediate product and potassium carbonate is 1:(0.9-1.2):(2-6).

4. A flame retardant cable material, characterized in that: The invention comprises the following components in parts by weight: 10-40 parts of ethylene-vinyl acetate copolymer, 5-30 parts of polyethylene resin, 2-10 parts of EPDM rubber, 50-60 parts of inorganic flame retardant, 1-10 parts of flame retardant synergist, 0.5-1 parts of silane coupling agent, and 0-10 parts of other additives; the flame retardant synergist comprises the flame retardant additive according to claim 1.

5. The flame-retardant cable material according to claim 4, characterized in that: In the flame-retardant cable material, the mass percentage of the flame-retardant synergist is 1%-10%.

6. The flame retardant cable material according to claim 4, characterized in that: The mass ratio of the inorganic flame retardant to the flame retardant synergist is 1:(0.03-0.2).

7. The flame retardant cable material according to claim 4, characterized in that: In the flame-retardant cable material, the mass percentage of the inorganic flame retardant is 40%-55%.

8. The flame-retardant cable material according to claim 4, characterized in that: Include at least one of the following: The inorganic flame retardant includes at least one of aluminum hydroxide or magnesium hydroxide, and the D50 of the inorganic flame retardant is less than 3 μm; The mass percentage of vinyl acetate in the ethylene-vinyl acetate copolymer is 18%-28%; The polyethylene resin includes at least one of linear low-density polyethylene, low-density polyethylene, medium-density polyethylene or high-density polyethylene; The Mooney viscosity of the EPDM rubber at 125° C. is 20-50; The silane coupling agent includes at least one of γ-aminopropyltriethoxysilane, vinyltriethoxysilane or γ-methacryloxypropyltrimethoxysilane.

9. The flame retardant cable material according to claim 4, characterized in that: The other auxiliary agents include the following components in parts by weight: 0.5-2 parts of antioxidant, 1-2 parts of silicone masterbatch, and 0.25-1.5 parts of lubricant.

10. A method for preparing the flame-retardant cable material according to any one of claims 4 to 9, characterized in that: The method comprises the following steps: subjecting raw materials to mixing, banburying, melt extrusion, granulation and drying in sequence to obtain the flame retardant cable material.

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