Halogen-free flame-retardant tpu material suitable for charging pile cable and preparation method thereof

Abstract

The application discloses a halogen-free flame-retardant TPU material suitable for charging pile cables and a preparation method thereof, and belongs to the technical field of TPU material processing, and is used for solving the technical problem that the flame-retardant property and wear resistance of the TPU material for cables in the prior art need to be further improved; the application comprises the following raw material components in parts by weight: 80-100 parts of a crosslinked thermoplastic elastomer, 10-20 parts of a modified filler, 10-20 parts of a flame-retardant chain extender, 3-5 parts of a stabilizer, 3-5 parts of an antioxidant, 3-5 parts of an ultraviolet absorber and 3-5 parts of a lubricant; in the application, after the modified thermoplastic elastomer is prepared, the modified thermoplastic elastomer is activated and crosslinked with a flame-retardant crosslinking agent, a silane structure is introduced into the structure, the flame-retardant crosslinking agent and the modified filler enhance the flame-retardant capacity of the material through synergistic effect, the hybrid polyurethane segment enhances the compatibility of the material with inorganic materials, and the wear resistance and the flame-retardant property of the material are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of TPU material processing, in particular to a halogen-free flame-retardant TPU material suitable for charging pile cables and a preparation method thereof. BACKGROUND

[0002] The development of flame-retardant TPU cable materials is mainly to meet the safety requirements of electric vehicle charging piles. Early TPU is widely used in the cable industry due to its excellent physical properties and processing flexibility. However, early TPU materials have shortcomings in flame retardant performance. With the improvement of environmental protection standards, the research focus shifts to non-halogen flame-retardant technology. This technology not only meets environmental protection requirements, but also maintains the mechanical strength and chemical resistance of the material. Modern flame-retardant TPU cable materials not only pass strict flame-retardant tests, but also withstand high temperatures and chemical corrosion, meeting high safety and environmental protection standards, becoming the ideal choice for charging pile cables.

[0003] The prior art CN113881216B discloses a wear-resistant flame-retardant modified polyurethane cable material and a preparation method thereof, which is made of thermoplastic polyurethane, polyolefin elastomer and modifier. The modifier includes a compatibilizer, a synergistic flame retardant and a filler. The compatibilizer is at least one of maleic anhydride grafted EVA and silane coupling agent. The synergistic flame retardant is a combination of aluminum diethyl phosphinate and nano magnesium hydroxide. The filler is at least two of nano calcium carbonate, nano aluminum oxide and nano carbon black. The invention uses thermoplastic polyurethane as the base material, and by mixing polyolefin elastomer and modifier, the flame retardant performance of thermoplastic polyurethane is improved, and the wear resistance is also improved.

[0004] However, the above patent content is to mix thermoplastic polyurethane and auxiliary materials through melt extrusion to improve the wear resistance and flame retardance of the material. However, the synergistic flame retardant is a combination of aluminum diethyl phosphinate and nano magnesium hydroxide, which has a large difference in polarity, resulting in weak interfacial bonding force, which leads to weak dispersion performance and synergistic cooperation ability of the two in the organic system. Therefore, the flame retardant performance of the material needs to be further improved, and the polarity difference between the inorganic components such as fillers and thermoplastic polyurethane also leads to poor compatibility between the whole material, so the wear resistance needs to be further improved.

[0005] In view of the above technical defects, a solution is proposed. SUMMARY

[0006] The purpose of the present application is to provide a halogen-free flame-retardant TPU material suitable for charging pile cables and a preparation method thereof, to solve the technical defects proposed in the background art.

[0007] The application can be achieved by the following technical scheme: a halogen-free flame-retardant TPU material suitable for charging pile cables, comprising the following raw material components in parts by weight: 80-100 parts of crosslinked thermoplastic elastomer, 10-20 parts of modified filler, 10-20 parts of flame-retardant chain extender, 3-5 parts of stabilizer, 3-5 parts of antioxidant, 3-5 parts of ultraviolet absorber and 3-5 parts of lubricant.

[0008] The preparation method of the crosslinked thermoplastic elastomer is as follows: 8-10 parts of activated thermoplastic elastomer, 3-5 parts of flame-retardant chain extender, 0.5-0.8 parts of triethylamine and 40-60 parts of N,N-dimethylformamide are weighed and added into a reaction kettle for stirring, the temperature of the reaction kettle is increased to 80-100 DEG C, and the reaction is kept for 2-4 h, and then the crosslinked thermoplastic elastomer is obtained through post-treatment.

[0009] The reaction principle for preparing the crosslinked thermoplastic elastomer is as follows: under the catalysis of high temperature and alkaline conditions, the epoxy groups in the flame-retardant chain extender are opened to generate free radicals which react with the hydroxyl groups in the activated thermoplastic elastomer, and finally a complex spatial network structure is formed, and the crosslinked thermoplastic elastomer is prepared.

[0010] Further, the post-treatment includes the following steps: after the reaction is completed, the reaction kettle is cooled to room temperature, the reaction liquid is added into a rotary evaporator with a water bath temperature of 80-100 DEG C, and the crosslinked thermoplastic elastomer is obtained through reduced pressure distillation until no liquid is produced.

[0011] The preparation method of the activated thermoplastic elastomer further includes the following steps:

[0012] A1, diethylene glycol ether, 1,5-hexadiene-3,4-diol, dibutyltin dilaurate and toluene are added into a reaction kettle, the temperature of the reaction kettle is increased to 60-80 DEG C, then toluene-2,6-diisocyanate solution is added into the reaction kettle, the reaction is kept for 2-3 h, and then the modified thermoplastic elastomer is obtained through post-treatment after the reaction is completed;

[0013] The reaction equation for preparing the modified thermoplastic elastomer is as follows:

[0014]

[0015] In the formula: ; .

[0016] The reaction principle for preparing the modified thermoplastic elastomer is as follows: under the catalysis of the catalyst, the isocyanate and the polyol undergo polymerization reaction, the isocyanate groups (-NCO) react with the hydroxyl groups (-OH) to generate carbamate bonds (-NHCOO-), and through continuous polymerization and control of the amount of reactants, the modified thermoplastic elastomer with hydroxyl groups at the end is finally prepared.

[0017] A2, the oxidation solution and N, N-dimethylformamide are added into the reaction kettle and stirred, the temperature of the reaction kettle is lowered to 0-5℃, then the modified thermoplastic elastomer is added into the reaction kettle, and the reaction is kept for 1-2h, and the activated thermoplastic elastomer is obtained after the post-treatment.

[0018] The reaction equation for preparing the activated thermoplastic elastomer is as follows:

[0019]

[0020] The reaction principle for preparing the activated thermoplastic elastomer is as follows: under the conditions of alkaline and low temperature, the double bond in the modified thermoplastic elastomer is oxidized to hydroxyl by potassium permanganate, which enhances the reactivity of the modified thermoplastic elastomer, and finally the activated thermoplastic elastomer is prepared.

[0021] Further, in step A1, the use amount ratio of diethylene glycol ether, 1, 5-hexadiene-3, 4-diol, dibutyl tin dilaurate, toluene and toluene-2, 6-diisocyanate solution is 4-5g:8-10g:0.2-0.5g:40-60mL:10-12mL, the toluene-2, 6-diisocyanate solution is prepared by toluene-2, 6-diisocyanate and toluene according to the use amount ratio of 1g:2-3mL, and the post-treatment includes: after the reaction is completed, the reaction kettle is lowered to room temperature, the reaction liquid is added into the rotary evaporator with a water bath temperature of 80-100℃, and the modified thermoplastic elastomer is obtained by distillation under reduced pressure until no liquid is collected; in step A2, the use amount ratio of the oxidation solution, N, N-dimethylformamide and the modified thermoplastic elastomer is 3-5mL:20-30mL:5-8g, the oxidation solution is prepared by potassium permanganate, sodium hydroxide and deionized water according to the use amount ratio of 3-5g:0.3-0.5g:20-30mL, and the post-treatment includes: after the reaction is completed, the reaction kettle is raised to room temperature, the reaction liquid is added into the rotary evaporator with a water bath temperature of 80-100℃, and the activated thermoplastic elastomer is obtained by distillation under reduced pressure until no liquid is collected.

[0022] Further, the preparation method of the flame-retardant chain extender comprises the following steps:

[0023] B1, the flame-retardant monomer, (2-methyl-2-propylene) succinic anhydride, platinum tetrachloride and dimethyl sulfoxide are added into the reaction kettle, then the temperature of the reaction kettle is raised to 120-140℃ after nitrogen protection, the reaction is kept for 2-4h, and the reaction precursor is obtained after the post-treatment;

[0024] The reaction equation for preparing the reaction precursor is as follows:

[0025]

[0026] In the formula: .

[0027] The reaction principle for preparing the reaction precursor is that, under the catalysis of a catalyst and high temperature and the protection of a nitrogen atmosphere, the silicon-hydrogen bond of the flame-retardant monomer and the double bond on the (2-methyl-2-propenyl) succinic anhydride undergo a silicon-hydrogen addition reaction, and finally the reaction precursor is prepared. The mass spectrum analysis data of the reaction precursor is m / z: 454.14 (100.0%), 455.14 (31.5%), 456.14 (5.6%), 456.13 (3.4%), 457.14 (1.4%).

[0028] B2, the reaction precursor, N,N'-di(2-hydroxyethyl)-1, 3-propanediamine, phosphorus trichloride and pyridine are added to the reaction kettle, the temperature of the reaction kettle is increased to 80-100°C, and the reaction is kept for 2-3h, and then the modified flame retardant is obtained after post-processing;

[0029] The reaction equation for preparing the modified flame retardant is:

[0030]

[0031] The reaction principle for preparing the modified flame retardant is that, under the catalysis of a catalyst and high temperature, the secondary amino group in the reaction precursor undergoes ring-opening reaction with N,N'-di(2-hydroxyethyl)-1, 3-propanediamine to generate amide and carboxyl group, and the carboxyl group further reacts with the hydroxyl group on N,N'-di(2-hydroxyethyl)-1, 3-propanediamine to further crosslink to form a complex spatial network structure, and finally the modified flame retardant is prepared.

[0032] B3, the modified flame retardant, epichlorohydrin, sodium carbonate, triethyl borate and ethyl acetate are added to the reaction kettle, the temperature of the reaction kettle is reduced to 0-5°C, and the reaction is kept for 1-2h, and then the flame-retardant chain extender is obtained after post-processing.

[0033] The reaction equation for preparing the flame-retardant chain extender is:

[0034]

[0035] The reaction principle for preparing the flame-retardant chain extender is that, under the catalysis of weak alkaline and low temperature, the epoxy group is protected, and a large number of hydroxyl groups on the modified flame retardant and chlorine groups on the epichlorohydrin react to introduce a large number of epoxy groups on the modified flame retardant, and finally the flame-retardant chain extender is prepared.

[0036] Further, in step B1, the amount ratio of the flame retardant monomer, (2-methyl-2-propenyl) succinic anhydride, platinum tetrachloride and dimethyl sulfoxide is 8-10 g:4-5 g:0.3-0.5 g:40-60 mL, and the post-treatment includes: after the reaction is completed, the reaction kettle is lowered to room temperature, the nitrogen is turned off, and the reaction liquid is added to a rotary evaporator with a water bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is collected, to obtain a reaction precursor; in step B2, the amount ratio of the reaction precursor, N,N'-bis(2-hydroxyethyl)-1,3-propanediamine, phosphorus trichloride and pyridine is 8-10 g:3-5 g:0.3-0.5 g:40-60 mL, and the post-treatment includes: after the reaction is completed, the reaction kettle is lowered to room temperature, the reaction liquid is added to a rotary evaporator with a water bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is collected, to obtain a modified flame retardant; in step B3, the amount ratio of the modified flame retardant, epichlorohydrin, sodium carbonate, triethyl borate and ethyl acetate is 8-10 g:4-5 g:1-2 g:0.3-0.5 g:40-60 mL, and the post-treatment includes: after the reaction is completed, the reaction kettle is lowered to room temperature, the reaction liquid is added to a rotary evaporator with a water bath temperature of 80-100°C, and distilled under reduced pressure until no liquid is collected, to obtain a flame-retardant chain extender.

[0037] Further, the preparation method of the flame retardant monomer includes the following steps:

[0038] C1, vinylmethylsilane, trimethylchlorosilane, tris(triphenylphosphine) rhodium (I) chloride and toluene are added to a reaction kettle, nitrogen is introduced for protection, and the reaction is carried out at room temperature for 1-2 h, and the modified silane is obtained by post-treatment;

[0039] The reaction equation for preparing the modified silane is:

[0040]

[0041] The reaction principle for preparing the modified silane is: under the catalysis of the catalyst, the silicon-hydrogen bond is activated, and an elimination reaction occurs with the silicon-chlorine bond under the protection of nitrogen, and finally the modified silane is obtained. The mass spectrum analysis data of the modified silane is m / z: 158.09 (100.0%), 159.09 (10.2%), 159.10 (7.8%), 160.09 (7.0%), 160.10 (1.1%).

[0042] C2, the modified silane, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis(triphenylphosphine)palladium and dimethyl sulfoxide are added to a reaction kettle, nitrogen is introduced for protection, the temperature of the reaction kettle is raised to 80-100°C, and the reaction is carried out for 1-2 h, and the phosphine silane is obtained by post-treatment;

[0043] The reaction equation for preparing the phosphine silane is:

[0044]

[0045] The reaction principle for preparing phosphosilane is that the carbon-carbon double bond on the modified silane and the phosphorus-hydrogen bond on 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are reacted under catalysis of a catalyst and at high temperature, and finally phosphosilane is prepared. The mass spectrometry data of the phosphosilane is m / z: 372.11 (100.0%), 373.12 (20.9%), 373.11 (10.2%), 374.11 (7.0%), 374.12 (4.6%), 375.11 (1.7%).

[0046] C3, phosphosilane, ammonium fluoride and dimethyl sulfoxide are added into a reaction kettle, nitrogen is introduced for protection, the temperature of the reaction kettle is increased to 80-100°C, and the reaction is kept for 1-2 h, and then the flame-retardant monomer is obtained after post-treatment.

[0047] The reaction equation for preparing the flame-retardant monomer is:

[0048]

[0049] The reaction principle for preparing the flame-retardant monomer is that the fluorine ion in ammonium fluoride attacks the silicon atom on trimethylsilane, and since a strong silicon-fluorine bond is formed between the fluorine atom and the silicon atom, the trimethylsilane group is separated from the molecule, and after the trimethylsilane group is removed, the shielded Si-H bond is exposed again to obtain the flame-retardant monomer. The mass spectrometry data of the flame-retardant monomer is m / z: 300.07 (100.0%), 301.08 (17.6%), 301.07 (5.1%), 302.07 (3.4%), 302.08 (2.8%).

[0050] Further, in step C1, the amount ratio of vinylmethylsilane, trimethylchlorosilane, tris(triphenylphosphine)rhodium(I) chloride and toluene is 4-6 g:3-5 g:0.3-0.5 g:40-60 mL, and the post-treatment includes: after the reaction is completed, the nitrogen is closed after the reaction kettle is reduced to room temperature, and the reaction liquid is added to a rotary evaporator with a water bath temperature of 80-100℃, and distilled under reduced pressure until no liquid is collected, to obtain a modified silane; in step C2, the amount ratio of modified silane, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis(triphenylphosphine)palladium and dimethyl sulfoxide is 4-6 g:8-10 g:0.3-0.5 g:40-60 mL, and the post-treatment includes: after the reaction is completed, the nitrogen is closed after the reaction kettle is reduced to room temperature, and the reaction liquid is added to a rotary evaporator with a water bath temperature of 80-100℃, and distilled under reduced pressure until no liquid is collected, to obtain a phosphated silane; in step C3, the amount ratio of phosphated silane, ammonium fluoride and dimethyl sulfoxide is 4-6 g:1-2 g:20-30 mL, and the post-treatment includes: after the reaction is completed, the nitrogen is closed after the reaction kettle is reduced to room temperature, and the reaction liquid is added to a rotary evaporator with a water bath temperature of 80-100℃, and distilled under reduced pressure until no liquid is collected, to obtain a flame-retardant monomer.

[0051] Further, the preparation method of the modified filler includes the following steps:

[0052] D1, magnesium hydroxide and aluminum hydroxide are added to a grinder and ground and mixed uniformly to obtain a mixed powder;

[0053] D2, the flame-retardant powder, triethylamine and deionized water are added to a reaction kettle and stirred, the temperature of the reaction kettle is reduced to 0-5℃, then 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added to the reaction kettle, and the reaction is kept for 30-40 min, and the post-treatment obtains the modified filler.

[0054] The reaction principle for preparing the modified filler is:

[0055] Further, in step D1, the amount ratio of magnesium hydroxide and aluminum hydroxide is 1 g:2-3 g, and the mesh size of the screen is 300-600 meshes; in step D2, the stirring rate of the reaction kettle is 80-120 rpm, and the amount ratio of the flame-retardant powder, triethylamine, 3-(2,3-epoxypropoxy) propyl trimethoxysilane and deionized water is 8-10 g:0.3-0.5 g:2-3 g:40-60 mL, and the post-treatment includes: after the reaction is completed, the reaction kettle is raised to room temperature, the reaction liquid is filtered to collect the filter cake, the filter cake is placed in a drying oven with a temperature of 60℃ for vacuum drying until the filter cake reaches a constant weight, to obtain the modified filler.

[0056] The preparation method of the halogen-free flame-retardant TPU material suitable for charging pile cables includes the following steps:

[0057] S1, crosslinked thermoplastic elastomer, modified filler, flame-retardant chain extender, stabilizer, antioxidant, ultraviolet absorber and lubricant are added to a stirred tank, mixed uniformly to obtain a TPU material;

[0058] S2, the TPU material precursor is added to a twin-screw extruder, and is melt-extruded to obtain a TPU material.

[0059] Further, in step S2, the temperatures of the eight temperature zones of the twin-screw extruder from the feeding port to the discharging port are 160℃, 165℃, 265℃, 170℃, 170℃, 180℃, 180℃, respectively, the main motor speed of the twin-screw extruder is 80-120rpm, and the pressure is 100-150bar, and the TPU material is obtained by melt-extrusion.

[0060] Further, the stabilizer is one or more of 2-hydroxy-4-n-octyloxybenzophenone, bis(2,2,6,6-tetramethylpiperidyl) methylene succinate and 2-(2-hydroxy-3,5-di-tert-butylphenyl)-5-chlorobenzotriazole; the antioxidant is one or more of tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester, tris(2,4-di-tert-butylphenyl)phosphate and hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate; the ultraviolet absorber is one or more of diphenyl triazolyl diphenyl triazoline, 2-(2-hydroxy-3-tert-butyl-5-methylphenyl)-2H-benzotriazole-4-ketone) and 2-hydroxy-4-methoxybenzoic acid butyl ester; and the lubricant is one or more of calcium stearate, zinc stearate and polyethylene wax.

[0061] The present application has the following advantages:

[0062] 1, the TPU material prepared in the present application, in the process of combustion, the phosphoric acid component in the flame-retardant chain extender decomposes to produce acidic substances, promotes the carbonization of organic chain segments to form a molten carbon layer, and the decomposition of the tertiary amine group produces a large amount of ammonia gas, which cooperates with the water vapor produced by the thermal decomposition of the modified filler to take away a large amount of heat, and makes the molten carbon layer foam to form a flame-retardant structure, and the metal oxides produced by the high-temperature decomposition of the modified filler form a protective slag layer to isolate the heat transfer with the foamed carbon layer, and a large amount of silicon groups in the chain segment endow the material with a higher ignition point, inhibit the process of organic pyrolysis, and significantly improve the flame-retardant ability of the material.

[0063] 2、The application is prepared by activating the thermoplastic elastomer with a large number of active functional groups, cross-linking with a flame-retardant chain extender, and introducing a modified filler modified by a silane coupling agent into the system. Under the modification of the silane coupling agent, the interfacial bonding force between the materials is significantly enhanced, and after cross-linking by the flame-retardant chain extender, the polyurethane segment forms a complex three-dimensional structure, and the silane structure is introduced into the structure. On this basis, the modified filler serves as the skeleton of the TPU material, and the two cooperate to significantly improve the wear resistance and impact resistance of the material.

[0064] 3、In the process of preparing the flame-retardant chain extender, first, the silicon-hydrogen bond is protected, then a flame-retardant organic compound is used to form cross-linking with the silane structure to form a more stable organic structure, and the protection group is removed to give the flame-retardant monomer excellent reactivity, and the reaction monomer is cross-linked. Through the selection of reactants, the ring-opening and cross-linking process of the cyclic anhydride is completed, and through the selection of reactants and optimization of the reaction process, the reaction steps are simplified, the process of industrial production of the flame-retardant chain extender is more simplified, so that the TPU material prepared by the application has excellent industrialization prospect. DETAILED DESCRIPTION

[0065] The technical solutions of the application will be described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application. Example 1

[0066] The embodiment provides a preparation method of a halogen-free flame-retardant TPU material suitable for charging pile cable, comprising the following steps:

[0067] S1, preparing a flame-retardant monomer

[0068] Take 10.0g of vinylmethylsilane, 8.0g of trimethylchlorosilane, 0.8g of tris(triphenylphosphine)rhodium(I) chloride and 100.0mL of toluene into a reaction kettle, protect by purging nitrogen, react at room temperature for 1h, after the reaction is completed, the reaction kettle is cooled to room temperature, the nitrogen is turned off, and the reaction liquid is added into a rotary evaporator with a water bath temperature of 80℃, distilled under reduced pressure until no liquid is collected, and a modified silane is obtained;

[0069] Weighing: 12.0 g of modified silane, 18.0 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 0.8 g of tetrakis(triphenylphosphine)palladium and 100.0 mL of dimethyl sulfoxide into the reaction kettle, protect with nitrogen, increase the temperature of the reaction kettle to 80℃, and keep the reaction for 1 h. After the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with a water bath temperature of 80℃. Distill under reduced pressure until no liquid is collected to obtain phosphated silane;

[0070] Weighing: 10.0 g of phosphated silane, 3.0 g of ammonium fluoride and 50.0 mL of dimethyl sulfoxide into the reaction kettle, protect with nitrogen, increase the temperature of the reaction kettle to 80℃, and keep the reaction for 1 h. After the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with a water bath temperature of 80℃. Distill under reduced pressure until no liquid is collected to obtain flame-retardant monomer.

[0071] S2, Preparation of flame-retardant chain extender

[0072] Weighing: 18.0 g of flame-retardant monomer, 9.0 g of (2-methyl-2-propenyl) succinic anhydride, 0.8 g of platinum tetrachloride and 100.0 mL of dimethyl sulfoxide into the reaction kettle, protect with nitrogen, increase the temperature of the reaction kettle to 120℃, and keep the reaction for 2 h. After the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with a water bath temperature of 80℃. Distill under reduced pressure until no liquid is collected to obtain reaction precursor;

[0073] Weighing: 16.0 g of reaction precursor, 10.0 g of N,N'-bis(2-hydroxyethyl)-1,3-propanediamine, 0.8 g of phosphorus trichloride and 100.0 mL of pyridine into the reaction kettle, increase the temperature of the reaction kettle to 80℃, and keep the reaction for 2 h. After the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with a water bath temperature of 80℃. Distill under reduced pressure until no liquid is collected to obtain modified flame retardant;

[0074] Weighing: 18.0 g of modified flame retardant, 9.0 g of epichlorohydrin, 3.0 g of sodium carbonate, 0.8 g of triethyl borate and 100.0 mL of ethyl acetate into the reaction kettle, reduce the temperature of the reaction kettle to 5℃, and keep the reaction for 1 h. After the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with a water bath temperature of 80℃. Distill under reduced pressure until no liquid is collected to obtain flame-retardant chain extender.

[0075] S3, Preparation of crosslinked thermoplastic elastomer

[0076] Weighing: 10.0 g of toluene-2,6-diisocyanate and 30.0 mL of toluene to obtain toluene-2,6-diisocyanate solution;

[0077] Weighing: 9.0 g of diethylene glycol ether, 18.0 g of 1,5-hexadiene-3,4-diol, 0.8 g of dibutyl tin dilaurate and 100.0 mL of toluene into the reaction kettle, after the reaction kettle temperature is raised to 60℃, 20.0 mL of toluene-2,6-diisocyanate solution is added into the reaction kettle, and the reaction is carried out for 2 h, after the reaction is completed, the reaction kettle is reduced to room temperature, and the reaction liquid is added into the rotary evaporator with a water bath temperature of 80℃, and distilled under reduced pressure until no liquid is collected, to obtain a modified thermoplastic elastomer;

[0078] Weighing: 8.0 g of potassium permanganate, 0.8 g of sodium hydroxide and 50.0 mL of deionized water to prepare an oxidizing solution;

[0079] Weighing: 8.0 mL of the oxidizing solution and 50.0 mL of N,N-dimethylformamide into the reaction kettle and stir, after the reaction kettle temperature is reduced to 5℃, 16.0 g of the modified thermoplastic elastomer is added into the reaction kettle, and the reaction is carried out for 1 h, after the reaction is completed, the reaction kettle is raised to room temperature, and the reaction liquid is added into the rotary evaporator with a water bath temperature of 80℃, and distilled under reduced pressure until no liquid is collected, to obtain an activated thermoplastic elastomer;

[0080] Weighing: 18.0 g of the activated thermoplastic elastomer, 8.0 g of the flame-retardant chain extender, 1.2 g of triethylamine and 100.0 g of N,N-dimethylformamide into the reaction kettle and stir, after the reaction kettle temperature is raised to 80℃, the reaction is carried out for 2 h, after the reaction is completed, the reaction kettle is reduced to room temperature, and the reaction liquid is added into the rotary evaporator with a water bath temperature of 80℃, and distilled under reduced pressure until no liquid is collected, to obtain a crosslinked thermoplastic elastomer.

[0081] S4, preparation of TPU material

[0082] Weighing: 10.0 g of magnesium hydroxide and 20.0 g of aluminum hydroxide into the grinder and grind and mix uniformly, and pass through a 300 mesh screen to obtain a mixed powder;

[0083] Weighing: 18.0 g of the flame-retardant powder, 0.8 g of triethylamine and 100.0 mL of deionized water into the reaction kettle and stir, after the reaction kettle temperature is reduced to 5℃, 5.0 g of 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added into the reaction kettle, and the reaction is carried out for 30 min, after the reaction is completed, the reaction kettle is raised to room temperature, and the reaction liquid is filtered to collect the filter cake, and the filter cake is placed in a drying oven with a temperature of 60℃ for vacuum drying until the filter cake reaches a constant weight, to obtain a modified filler;

[0084] Take: 88.0g crosslinked thermoplastic elastomer, 16.0g modified filler, 16.0g flame retardant chain extender, 3.6g 2-hydroxy-4-n-octyloxybenzophenone, 3.6g tris(2,4-di-tert-butylphenyl) phosphate, 3.6g diphenyl triazolyl diphenyl triazoline and 3.6g polyethylene wax into a stirred tank, mix uniformly to get TPU material precursor;

[0085] The TPU material precursor is added to the twin-screw extruder, and the temperature of the eight temperature zones of the twin-screw extruder from the feeding port to the discharging port is 160℃, 165℃, 265℃, 170℃, 170℃, 180℃, 180℃, respectively. The main machine speed of the twin-screw extruder is 80rpm, and the pressure is 100bar. The TPU material is obtained by melt extrusion. Example 2

[0086] The present embodiment provides a preparation method of halogen-free flame-retardant TPU material suitable for charging pile cable, comprising the following steps:

[0087] S1, preparation of flame retardant monomer

[0088] Take: 12.0g vinylmethylsilane, 8.0g trimethylchlorosilane, 0.8g tris(triphenylphosphine) rhodium (I) chloride and 100.0mL toluene into the reaction kettle, protect with nitrogen, react at room temperature for 1h, after the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with water bath temperature of 80℃, distill under reduced pressure until no liquid is collected, to obtain modified silane;

[0089] Take: 10.0g modified silane, 18.0g 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 0.8g tetrakis(triphenylphosphine)palladium and 100.0mL dimethyl sulfoxide into the reaction kettle, protect with nitrogen, increase the temperature of the reaction kettle to 80℃, and keep the temperature for 1h. After the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with water bath temperature of 80℃, distill under reduced pressure until no liquid is collected, to obtain phosphated silane;

[0090] Take: 10.0g phosphated silane, 2.4g ammonium fluoride and 50.0mL dimethyl sulfoxide into the reaction kettle, protect with nitrogen, increase the temperature of the reaction kettle to 80℃, and keep the temperature for 1h. After the reaction is completed, close the nitrogen after the reaction kettle is reduced to room temperature, and add the reaction liquid into the rotary evaporator with water bath temperature of 80℃, distill under reduced pressure until no liquid is collected, to obtain flame retardant monomer. S2, preparation of flame retardant chain extender

[0091] Take: 18.0 g of flame retardant monomer, 9.0 g (2-methyl-2-propylene) succinic anhydride, 1.0 g of platinum tetrachloride and 100.0 mL of dimethyl sulfoxide into the reaction kettle, after purging with nitrogen, the temperature of the reaction kettle is raised to 140℃, and the reaction is carried out for 2h, after the reaction is completed, the reaction kettle is cooled to room temperature, the nitrogen is turned off, and the reaction liquid is added to the rotary evaporator with water bath temperature of 80℃, and distilled under reduced pressure until no liquid is collected. Reaction precursor is obtained;

[0092] Take: 18.0 g of reaction precursor, 9.0 g of N,N'-bis(2-hydroxyethyl)-1,3-propanediamine, 0.8 g of phosphorus trichloride and 100.0 mL of pyridine into the reaction kettle, the temperature of the reaction kettle is raised to 80℃, and the reaction is carried out for 2h, after the reaction is completed, the reaction kettle is cooled to room temperature, the reaction liquid is added to the rotary evaporator with water bath temperature of 100℃, and distilled under reduced pressure until no liquid is collected. Modified flame retardant is obtained;

[0093] Take: 18.0 g of modified flame retardant, 9.0 g of epoxy chloropropane, 2.4 g of sodium carbonate, 0.8 g of triethyl borate and 100.0 mL of ethyl acetate into the reaction kettle, the temperature of the reaction kettle is reduced to 0℃, and the reaction is carried out for 2h, after the reaction is completed, the reaction kettle is cooled to room temperature, the reaction liquid is added to the rotary evaporator with water bath temperature of 100℃, and distilled under reduced pressure until no liquid is collected. Flame retardant chain extender is obtained.

[0094] S3, preparation of crosslinked thermoplastic elastomer

[0095] Take: 10.0 g of toluene-2,6-diisocyanate and 20.0 mL of toluene to prepare toluene-2,6-diisocyanate solution;

[0096] Take: 9.0 g of diethylene glycol ether, 18.0 g of 1,5-hexadiene-3,4-diol, 0.8 g of dibutyltin dilaurate and 100.0 mL of toluene into the reaction kettle, after the temperature of the reaction kettle is raised to 80℃, 20.0 mL of toluene-2,6-diisocyanate solution is added to the reaction kettle, and the reaction is carried out for 3h, after the reaction is completed, the reaction kettle is cooled to room temperature, the reaction liquid is added to the rotary evaporator with water bath temperature of 100℃, and distilled under reduced pressure until no liquid is collected. Modified thermoplastic elastomer is obtained;

[0097] Weighing: 10.0 g of potassium permanganate, 0.8 g of sodium hydroxide and 50.0 mL of deionized water to prepare an oxidizing solution; weigh: 10.0 mL of the oxidizing solution and 50.0 mL of N,N-dimethylformamide into the reaction kettle and stir, after the temperature of the reaction kettle is lowered to 0°C, 18.0 g of modified thermoplastic elastomer is added into the reaction kettle, and the reaction is kept for 1 h, after the reaction is completed, the reaction kettle is raised to room temperature, and the reaction liquid is added into the rotary evaporator with a water bath temperature of 80°C, and distilled under reduced pressure until no liquid is collected, to obtain the activated thermoplastic elastomer;

[0098] Weighing: 18.0 g of activated thermoplastic elastomer, 9.0 g of flame-retardant chain extender, 1.2 g of triethylamine and 100.0 g of N,N-dimethylformamide into the reaction kettle and stir, the temperature of the reaction kettle is raised to 100°C, and the reaction is kept for 4 h, after the reaction is completed, the reaction kettle is lowered to room temperature, and the reaction liquid is added into the rotary evaporator with a water bath temperature of 80°C, and distilled under reduced pressure until no liquid is collected, to obtain the crosslinked thermoplastic elastomer.

[0099] S4, preparation of TPU material

[0100] Weighing: 10.0 g of magnesium hydroxide and 20.0 g of aluminum hydroxide into the grinder and grind and mix uniformly, and pass through a 600-mesh screen to obtain a mixed powder;

[0101] Weighing: 18.0 g of flame-retardant powder, 0.8 g of triethylamine and 100.0 mL of deionized water into the reaction kettle and stir, after the temperature of the reaction kettle is lowered to 0°C, 5.0 g of 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added into the reaction kettle, and the reaction is kept for 30 min, after the reaction is completed, the reaction kettle is raised to room temperature, and the reaction liquid is collected by suction filtration to collect the filter cake, and the filter cake is placed in a drying oven with a temperature of 60°C for vacuum drying until the filter cake reaches a constant weight, to obtain the modified filler;

[0102] Weighing: 96.0 g of crosslinked thermoplastic elastomer, 18.0 g of modified filler, 18.0 g of flame-retardant chain extender, 4.8 g of 2-hydroxy-4-n-octyloxybenzophenone, 4.8 g of tris(2,4-di-tert-butylphenyl) phosphate, 4.8 g of diphenyl triazolyl diphenyl triazoline and 4.8 g of polyethylene wax into the stirred kettle and mix uniformly to obtain a TPU material precursor;

[0103] The TPU material precursor is added into the twin-screw extruder, and the temperatures of the eight temperature zones of the twin-screw extruder from the feeding port to the discharging port are 160°C, 165, 265°C, 170°C, 170°C, 180°C, 180°C, respectively, the main machine rotation speed of the twin-screw extruder is 120 rpm, and the pressure is 150 bar, and the TPU material is obtained by melt extrusion. Example 3

[0104] The embodiment provides a preparation method of a halogen-free flame-retardant TPU material suitable for a charging pile cable, and comprises the following steps:

[0105] S1, preparing a flame-retardant monomer

[0106] Take 10.0 g of vinylmethylsilane, 8.0 g of trimethylchlorosilane, 0.8 g of tris(triphenylphosphine)rhodium(I) chloride and 100.0 mL of toluene and add them into a reaction kettle, introduce nitrogen protection, react at room temperature for 2 h, after the reaction is completed, the nitrogen is closed after the reaction kettle is reduced to room temperature, and the reaction liquid is added into a rotary evaporator with a water bath temperature of 100 DEG C, and distilled under reduced pressure until no liquid is collected, to obtain modified silane;

[0107] Take 12.0 g of modified silane, 18.0 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 0.8 g of tetrakis(triphenylphosphine)palladium and 100.0 mL of dimethyl sulfoxide and add them into a reaction kettle, introduce nitrogen protection, the temperature of the reaction kettle is increased to 100 DEG C, and heat preservation reaction is conducted for 2 h, after the reaction is completed, the nitrogen is closed after the reaction kettle is reduced to room temperature, and the reaction liquid is added into a rotary evaporator with a water bath temperature of 80 DEG C, and distilled under reduced pressure until no liquid is collected, to obtain phosphated silane;

[0108] Take 10.0 g of phosphated silane, 2.4 g of ammonium fluoride and 50.0 mL of dimethyl sulfoxide and add them into a reaction kettle, introduce nitrogen protection, the temperature of the reaction kettle is increased to 90 DEG C, and heat preservation reaction is conducted for 2 h, after the reaction is completed, the nitrogen is closed after the reaction kettle is reduced to room temperature, and the reaction liquid is added into a rotary evaporator with a water bath temperature of 90 DEG C, and distilled under reduced pressure until no liquid is collected, to obtain a flame-retardant monomer.

[0109] S2, preparing a flame-retardant chain extender

[0110] Take 18.0 g of the flame-retardant monomer, 9.0 g of (2-methyl-2-propenyl) succinic anhydride, 0.8 g of platinum tetrachloride and 100.0 mL of dimethyl sulfoxide and add them into a reaction kettle, introduce nitrogen protection, the temperature of the reaction kettle is increased to 130 DEG C, and heat preservation reaction is conducted for 3 h, after the reaction is completed, the nitrogen is closed after the reaction kettle is reduced to room temperature, and the reaction liquid is added into a rotary evaporator with a water bath temperature of 90 DEG C, and distilled under reduced pressure until no liquid is collected, to obtain a reaction precursor;

[0111] Take 18.0 g of the reaction precursor, 8.0 g of N,N'-bis(2-hydroxyethyl)-1,3-propanediamine, 0.8 g of phosphorus trichloride and 100.0 mL of pyridine and add them into a reaction kettle, the temperature of the reaction kettle is increased to 90 DEG C, and heat preservation reaction is conducted for 2 h, after the reaction is completed, the reaction liquid is added into a rotary evaporator with a water bath temperature of 90 DEG C, and distilled under reduced pressure until no liquid is collected, to obtain a modified flame retardant;

[0112] Weighing: 18.0 g of modified flame retardant, 10.0 g of epoxy chloropropane, 3.6 g of sodium carbonate, 0.8 g of triethyl borate and 100.0 mL of ethyl acetate into the reaction kettle, the temperature of the reaction kettle is reduced to 3℃, and the reaction is kept for 2 h. After the reaction is completed, the reaction kettle is reduced to room temperature, and the reaction liquid is added to the rotary evaporator with a water bath temperature of 100℃. Distillation under reduced pressure until no liquid is collected. The flame retardant chain extender is obtained.

[0113] S3, Preparation of crosslinked thermoplastic elastomer

[0114] Weighing: 10.0 g of toluene-2,6-diisocyanate and 25.0 mL of toluene to prepare a toluene-2,6-diisocyanate solution;

[0115] Weighing: 9.6 g of diethylene glycol ether, 18.0 g of 1,5-hexadiene-3,4-diol, 0.8 g of dibutyltin dilaurate and 100.0 mL of toluene into the reaction kettle. After the temperature of the reaction kettle is raised to 70℃, 20.0 mL of toluene-2,6-diisocyanate solution is added to the reaction kettle. Keep the reaction for 3 h. After the reaction is completed, the reaction kettle is reduced to room temperature, and the reaction liquid is added to the rotary evaporator with a water bath temperature of 90℃. Distillation under reduced pressure until no liquid is collected. The modified thermoplastic elastomer is obtained.

[0116] Weighing: 8.0 g of potassium permanganate, 0.8 g of sodium hydroxide and 50.0 mL of deionized water to prepare an oxidizing solution;

[0117] Weighing: 10.0 mL of oxidizing solution and 50.0 mL of N,N-dimethylformamide into the reaction kettle and stir. After the temperature of the reaction kettle is reduced to 3℃, 16.0 g of modified thermoplastic elastomer is added to the reaction kettle. Keep the reaction for 2 h. After the reaction is completed, the reaction kettle is raised to room temperature, and the reaction liquid is added to the rotary evaporator with a water bath temperature of 90℃. Distillation under reduced pressure until no liquid is collected. The activated thermoplastic elastomer is obtained.

[0118] Weighing: 18.0 g of activated thermoplastic elastomer, 10.0 g of flame retardant chain extender, 1.6 g of triethylamine and 100.0 g of N,N-dimethylformamide into the reaction kettle and stir. The temperature of the reaction kettle is raised to 90℃, and the reaction is kept for 3 h. After the reaction is completed, the reaction kettle is reduced to room temperature, and the reaction liquid is added to the rotary evaporator with a water bath temperature of 90℃. Distillation under reduced pressure until no liquid is collected. The crosslinked thermoplastic elastomer is obtained.

[0119] S4, Preparation of TPU material

[0120] Weighing: 10.0 g of magnesium hydroxide and 25.0 g of aluminum hydroxide into the grinder and grind and mix uniformly. Pass through a 450 mesh screen to obtain a mixed powder;

[0121] Weighing: 18.0 g of flame-retardant powder, 0.8 g of triethylamine and 100.0 mL of deionized water are added to the reaction kettle for stirring. After the temperature of the reaction kettle is reduced to 3℃, 6.0 g of 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added to the reaction kettle. After 30 min of incubation, the reaction is complete. After the reaction kettle is raised to room temperature, the reaction solution is filtered to collect the filter cake. The filter cake is placed in a drying oven at a temperature of 60℃ for vacuum drying until the filter cake reaches a constant weight. The modified filler is obtained.

[0122] Weighing: 96.0 g of crosslinked thermoplastic elastomer, 16.0 g of modified filler, 16.0 g of flame-retardant chain extender, 4.8 g of 2-hydroxy-4-n-octyloxybenzophenone, 4.8 g of tris(2,4-di-tert-butylphenyl) phosphate, 4.8 g of diphenyl triazolyl diphenyl triazoline, and 3.6 g of polyethylene wax are added to the stirring kettle and mixed uniformly to obtain a TPU material precursor.

[0123] The TPU material precursor is added to a twin-screw extruder. The temperatures of the eight temperature zones of the twin-screw extruder from the feeding port to the discharging port are 160℃, 165℃, 265℃, 170℃, 170℃, 180℃, and 180℃, respectively. The main machine rotation speed of the twin-screw extruder is 100 rpm, and the pressure is 125 bar. The TPU material is obtained by melt extrusion.

[0124] Comparative Example 1

[0125] The difference between this comparative example and Example 3 is that step S1 is cancelled, and in step S2, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is used instead of the flame-retardant monomer.

[0126] Comparative Example 2

[0127] The difference between this comparative example and Example 3 is that steps S1 and S2 are cancelled, and in step S2, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is used instead of the flame-retardant chain extender.

[0128] Comparative Example 3

[0129] The difference between this comparative example and Example 3 is that the activation step of the modified thermoplastic elastomer in step S3 is cancelled, and the modified thermoplastic elastomer is used instead of the activated thermoplastic elastomer in the preparation process of the crosslinked thermoplastic elastomer.

[0130] Performance test:

[0131] The limiting oxygen index of the TPU materials prepared in Examples 1-3 and Comparative Examples 1-3 is tested according to the standard GB / T 2406.2-2009 “Plastics-Determination of the burning behavior of plastics-Part 2: Guidance on the measurement of flame characteristics-Test method”;

[0132] The vertical burning grade of the TPU materials prepared from examples 1-3 and comparative examples 1-3 was tested according to the standard GB / T 2408-2021 "Determination of the Burning Behavior of Plastics Horizontal and Vertical Methods";

[0133] The relative volume loss and tensile strength of the TPU materials prepared from examples 1-3 and comparative examples 1-3 were tested according to the standard GB / T 33091-2016 "Polyurethane Sifter Plate";

[0134] The Izod impact strength of the TPU materials prepared from examples 1-3 and comparative examples 1-3 was tested according to the standard GB / T 1843-2008 "Determination of the Izod Impact Strength of Plastics";

[0135] The specific data are shown in Table 1:

[0136] Table 1: Performance test data table of each sample

[0137] Item Group Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Limiting Oxygen Index / % 38.3 39.3 41.3 35.3 33.3 37.5 Vertical Burning Rating V-0 V-0 V-0 V-1 V-1 V-1 Relative volume wear / mm 3 ]] 43 41 38 56 65 53 Tensile Strength / MPa 45 48 56 42 37 41 Izod impact strength / kJ m -2 ]] 63.3 64.5 66.2 58.3 48.9 59.3

[0138] Data analysis:

[0139] Comparative analysis of the data in Table 1 above, the limiting oxygen index of the composite polyurethane prepared by the present application is 41.3%, the vertical burning grade is V-0, the relative volume loss is 38mm 3 , the tensile strength is 56MPa, and the Izod impact strength is 66.2kJ·m -2 at the same time, all the data are better than the comparative examples, which shows that: the present application is to prepare a modified thermoplastic elastomer, then activate it to introduce a large number of active functional groups and crosslink with a flame-retardant crosslinking agent, introduce a silane structure in the structure, the flame-retardant crosslinking agent and the modified filler enhance the flame-retardant ability of the material through synergistic effect, at the same time, the hybrid polyurethane segment and enhance the crosslinking ability with inorganic materials, finally improve the wear resistance and flame retardant properties of the material.

[0140] The above content is only an example and description of the structure of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific examples, as long as they do not deviate from the structure of the invention or exceed the scope defined by the present claims, which shall belong to the protection scope of the present application.

Claims

1. A halogen-free flame-retardant TPU material suitable for charging pile cable, characterized in that, The raw material components include the following by weight: 80-100 parts of crosslinked thermoplastic elastomer, 10-20 parts of modified filler, 10-20 parts of flame-retardant chain extender, 3-5 parts of stabilizer, 3-5 parts of antioxidant, 3-5 parts of ultraviolet absorber and 3-5 parts of lubricant; The preparation method of the crosslinked thermoplastic elastomer comprises the following steps: The preparation method of the activated thermoplastic elastomer comprises the following steps: A1, diethylene glycol ether, 1,5-hexadiene-3,4-diol, dibutyltin dilaurate and toluene are added to the reaction kettle, the temperature of the reaction kettle is raised to 60-80℃, then toluene-2,6-diisocyanate solution is added to the reaction kettle, and the reaction is carried out for 2-3h, and then the modified thermoplastic elastomer is obtained after post-treatment; A2, the oxidation liquid and N,N-dimethylformamide are added to the reaction kettle and stirred, the temperature of the reaction kettle is lowered to 0-5℃, then the modified thermoplastic elastomer is added to the reaction kettle, and the reaction is carried out for 1-2h, and then the activated thermoplastic elastomer is obtained after post-treatment; The preparation method of the flame-retardant chain extender comprises the following steps: B1, the flame-retardant monomer, (2-methyl-2-propylene) succinic anhydride, platinum tetrachloride and dimethyl sulfoxide are added to the reaction kettle, nitrogen is introduced for protection, the temperature of the reaction kettle is raised to 120-140℃, and the reaction is carried out for 2-4h, and then the reaction precursor is obtained after post-treatment; B2, the reaction precursor, N,N'-di(2-hydroxyethyl)-1,3-propanediamine, phosphorus trichloride and pyridine are added to the reaction kettle, the temperature of the reaction kettle is raised to 80-100℃, and the reaction is carried out for 2-3h, and then the modified flame retardant is obtained after post-treatment; B3, the modified flame retardant, epoxy chloropropane, sodium carbonate, triethyl borate and ethyl acetate are added to the reaction kettle, the temperature of the reaction kettle is lowered to 0-5℃, and the reaction is carried out for 1-2h, and then the flame-retardant chain extender is obtained after post-treatment; The preparation method of the flame-retardant monomer comprises the following steps: C1, vinylmethylsilane, trimethylchlorosilane, tris(triphenylphosphine) rhodium(I) chloride and toluene are added to the reaction kettle, nitrogen is introduced for protection, and the reaction is carried out for 1-2h at room temperature, and then the modified silane is obtained after post-treatment; C2, the modified silane, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis(triphenylphosphine)palladium and dimethyl sulfoxide are added to the reaction kettle, nitrogen is introduced for protection, the temperature of the reaction kettle is raised to 80-100℃, and the reaction is carried out for 1-2h, and then the phosphosilane is obtained after post-treatment; C3, the phosphosilane, ammonium fluoride and dimethyl sulfoxide are added to the reaction kettle, nitrogen is introduced for protection, the temperature of the reaction kettle is raised to 80-100℃, and the reaction is carried out for 1-2h, and then the flame-retardant monomer is obtained after post-treatment.

2. The halogen-free flame retardant TPU material suitable for charging pile cable according to claim 1, characterized in that, In step A1, the ratio of diethylene glycol ether, 1,5-hexadiene-3,4-diol, dibutyl tin dilaurate, toluene and toluene-2,6-diisocyanate solution is 4-5g:8-10g:0.2-0.5g:40-60mL:10-12mL; in step A2, the ratio of oxidizing solution, N,N-dimethylformamide and modified thermoplastic elastomer is 3-5mL:20-30mL:5-8g.

3. The halogen-free flame retardant TPU material suitable for charging pile cable according to claim 1, characterized in that, In step B1, the ratio of flame-retardant monomer, (2-methyl-2-propenyl) succinic anhydride, platinum tetrachloride and dimethyl sulfoxide is 8-10g:4-5g:0.3-0.5g:40-60mL; in step B2, the ratio of reaction precursor, N,N'-bis(2-hydroxyethyl)-1,3-propanediamine, phosphorus trichloride and pyridine is 8-10g:3-5g:0.3-0.5g:40-60mL; in step B3, the ratio of modified flame retardant, epichlorohydrin, sodium carbonate, triethyl borate and ethyl acetate is 8-10g:4-5g:1-2g:0.3-0.5g:40-60mL.

4. The halogen-free flame retardant TPU material suitable for charging pile cable according to claim 1, characterized in that, In step C1, the ratio of vinylmethylsilane, trimethylchlorosilane, tris(triphenylphosphine) rhodium(I) chloride and toluene is 4-6g:3-5g:0.3-0.5g:40-60mL; in step C2, the ratio of modified silane, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, tetrakis(triphenylphosphine) palladium and dimethyl sulfoxide is 4-6g:8-10g:0.3-0.5g:40-60mL; in step C3, the ratio of phosphosilane, ammonium fluoride and dimethyl sulfoxide is 4-6g:1-2g:20-30mL.

5. The halogen-free flame retardant TPU material suitable for charging pile cable according to claim 1, characterized in that, The preparation method of the modified filler comprises the following steps: D1, magnesium hydroxide and aluminum hydroxide are added to a grinder for grinding and mixing uniformly, and sieving to obtain a mixed powder; D2, the flame-retardant powder, triethylamine and deionized water are added to a reaction kettle for stirring, the temperature of the reaction kettle is reduced to 0-5℃, then 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added to the reaction kettle, and the reaction is kept for 30-40min, and post-treatment is performed to obtain the modified filler.

6. The halogen-free flame retardant TPU material suitable for charging pile cable according to claim 5, characterized in that, In step D1, the ratio of magnesium hydroxide and aluminum hydroxide is 1g:2-3g, and the mesh size of the sieve is 300-600 meshes; in step D2, the stirring rate of the reaction kettle is 80-120rpm, and the ratio of the flame-retardant powder, triethylamine, 3-(2,3-epoxypropoxy) propyl trimethoxysilane and deionized water is 8-10g:0.3-0.5g:2-3g:40-60mL.

7. Process for the preparation of a halogen-free flame-retardant TPU material suitable for charging post cables according to any one of claims 1-6, characterized in that, Comprising the following steps: S1, the crosslinked thermoplastic elastomer, modified filler, flame-retardant chain extender, stabilizer, antioxidant, ultraviolet absorber and lubricant are added to a stirring kettle for mixing uniformly to obtain a TPU material precursor; S2, the TPU material precursor is added to a twin-screw extruder for melt extrusion to obtain a TPU material.

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