Modified polyurethane cable applied to new energy automobile and preparation method of modified polyurethane cable

Abstract

The invention relates to the technical field of vehicle cables, in particular to a modified polyurethane cable applied to a new energy automobile and a preparation method of the modified polyurethane cable. The invention provides a modified polyurethane cable applied to a new energy automobile and a preparation method thereof based on performance modification of flame retardance and strength of a polyurethane cable of the new energy automobile, provides a polyurethane material with a three-layer structure, and adds two different flame retardant materials in an inner layer, an outer layer and a middle layer, finally, the strength of the material is guaranteed, the shock resistance and flame retardance of the modified polyurethane are improved, and the modified polyurethane is suitable for industrial popularization.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle cables, and in particular to a modified polyurethane cable used in new energy vehicles and a preparation method thereof. Background Art

[0002] Wires and cables have been used for the transmission of various electrical energy and signals for many years. Polymer materials have become the first choice for wire and cable base materials due to their light weight, excellent electrical insulation and easy molding. Traditional PVC cable materials are widely used in wire and cable materials because they contain chlorine elements and have excellent flame retardancy. However, they generate a large amount of toxic gases and smoke when burned, which seriously endangers people's lives and property safety. The hydrogen chloride gas released when PVC cable materials burns can also cause corrosion to equipment, thereby causing "secondary pollution."

[0003] At present, people usually use inorganic flame retardants Mg(OH)2 and Al(OH)3 to flame retard polymer materials. China Patent Publication No. CN102140192A, low-smoke halogen-free polyolefin composite material and preparation method thereof, uses Mg(OH)2 to flame retard polymers, but its flame retardant efficiency is low, and more than 60% needs to be added to achieve higher flame retardant requirements, which greatly reduces the mechanical properties of the material, and the prepared cable is very hard, with a hardness generally around A95. The high amount of powder added causes a significant decrease in processing performance and increased energy consumption. Usually, in order to improve the flame retardant efficiency of inorganic flame retardants, flame retardant synergist red phosphorus is added to prepare halogen-free flame retardant cable materials, so that the amount of inorganic flame retardant will be greatly reduced, thereby not excessively reducing the mechanical properties of the material. However, since red phosphorus is prone to produce highly toxic phosphine gas and red phosphorus dust is prone to explosion, red phosphorus must be surface treated before it can be used safely and effectively. In addition, the inherent purple-red color of red phosphorus itself greatly limits the application of cable materials containing red phosphorus. However, flame-retardant cable materials containing red phosphorus will emit a large amount of pungent odor and smoke during the production process and when burned, polluting the environment. Therefore, it is imperative to prepare halogen-free, environmentally friendly, soft, and highly flame-retardant cable materials.

[0004] Therefore, based on the flame retardancy and strength modification of the polyurethane cable for new energy vehicles, this method proposes a modified polyurethane cable for new energy vehicles and a preparation method thereof, and proposes a three-layer polyurethane material, which significantly improves the flame retardancy, seismic resistance and material strength of the cable under the new process, and is suitable for industrial promotion. Summary of the invention

[0005] The present invention aims to provide a modified polyurethane cable for use in new energy vehicles and a preparation method thereof. By improving relevant processes and raw materials, the flame retardancy and material strength of the modified polyurethane cable for new energy vehicles are improved.

[0006] Key points of this method: 1. In the method designed by the present invention, the polyurethane cable material is composed of three layers, namely the outer layer, the inner layer and the middle foamed layer of polyurethane. This requires ensuring that the layers can be well bonded to avoid separation during later use. Therefore, the outer layer and the middle layer are bonded with polyurethane glue, and the uniformity of the glue coating must be ensured. The inner layer is coated on the surface of the foamed middle layer. This structure similar to "mechanical bite" requires the inner layer to penetrate into the interior of the middle layer, which requires that the foaming pores of the middle layer cannot be too small so as not to affect the wetting effect of the inner layer; 2. The core of the present invention is to improve the flame retardant effect of polyurethane, so the uniform dispersion of the flame retardant inside the material is particularly important, which requires ensuring continuous observation during the mixing process and the rationality of the stirring method.

[0007] The specific implementation scheme of a modified polyurethane cable applied to new energy vehicles and a preparation method thereof according to the present invention is as follows:

[0008] S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0009] The inner layer raw materials include: 80-100 parts of polyether polyol, 0.4-0.7 parts of deionized water, 0.1-0.4 parts of dibutyltin, 0.4-0.6 parts of triethylamine, 1-4 parts of silicone glycol copolymer, 120-160 parts of 4,4-diphenylmethane diisocyanate, and 5-10 parts of inner layer flame retardant;

[0010] The outer layer raw materials include: 50-100 parts of thermoplastic polyurethane elastomer, 30-80 parts of styrene-ethylene-butadiene-styrene block copolymer, 6-20 parts of naphthenic oil, 50-70 parts of outer layer flame retardant, 8-15 parts of silicon dioxide, 1-3 parts of zinc stearate, 1-3 parts of pentaerythritol ester, and 3-6 parts of porous alumina;

[0011] Raw materials for the middle foaming layer: 20-40 parts of plastic polyurethane elastomer, 10-30 parts of styrene-ethylene-butadiene-styrene block copolymer, 2-8 parts of naphthenic oil, 15-25 parts of outer layer flame retardant, 3-5 parts of silicon dioxide, 0.3-1 parts of zinc stearate, 0.3-1 parts of pentaerythritol ester, and 1-2 parts of porous alumina;

[0012] The inner flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine and triethylamine, with a ratio of 1:200-400:0.5-1.5:40-60;

[0013] The outer flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:10-30;

[0014] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0015] The first step: using a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain an outer flame retardant, the ball milling speed is 100-300rpm, and the ball milling time is 100-200min;

[0016] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 15-30 minutes;

[0017] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 30-60 minutes to mix the raw materials evenly;

[0018] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer, the processing temperature is 160-200°C, the screw speed is 100-600rpm, and the processing time is 30-120min;

[0019] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0020] Step 1: Repeat the process from step 1 to step 4 in S2 to prepare an intermediate polyurethane layer;

[0021] Step 2: The middle polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 120-160°C, the pressure is 20-25MPa, and the time is 1-4h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed, and the thickness is 1-3mm to obtain the middle foaming layer;

[0022] Step 3: Use polyurethane glue to bond the middle foaming layer to the outer polyurethane layer;

[0023] S4. Prepare the inner flame retardant in three steps according to the process formula;

[0024] The first step: taking 70%-90% of the total chloroform solution, dispersing the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0025] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0026] Step 3: add triethylamine solution to the mixed solution in step 2, then heat to 50-70°C under nitrogen protection, stir for 15-20h, cool to room temperature, filter, wash and dry to obtain inner flame retardant;

[0027] S5. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0028] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer and inner flame retardant at a stirring speed of 100-200 rpm for 30-60 minutes;

[0029] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 30-60 seconds at a speed of 300-400 rpm;

[0030] Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S3 and scrape it flat with a scraping thickness of 3-5 mm. Curing it at 60-80°C for 120-140h to obtain the desired modified polyurethane cable material.

[0031] Beneficial effects:

[0032] (1) The polyurethane cable material in the method designed by the present invention is composed of three layers, namely, an outer layer, an inner layer and a middle foamed layer of polyurethane, wherein the inner layer is a porous structure and the outer layer is a solid structure, which is conducive to improving the seismic and impact resistance of the material. The outer layer is a solid layer and can also improve the friction resistance of the material;

[0033] (2) In the method designed by the present invention, flame retardants are added to the outer layer, inner layer and middle layer respectively. The flame retardants have a good effect on improving the high temperature resistance and flame retardancy of the material. The flame retardants added to the outer layer and the middle layer are mainly expandable graphite. This method can not only improve the strength of the outer layer of the material, but also improve the thermal conductivity of the outer layer of the material, thereby avoiding the problem of local heat concentration in the material causing fire or line burning and leakage;

[0034] (3) In the method designed by the present invention, the inner layer is coated on the surface of the middle layer, and the middle layer is foamed, which can improve the bonding strength between the layers and avoid detachment of the outer layer and the inner layer during long-term use due to direct bonding, thereby ensuring the stability of material properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 The present invention is a preparation flow chart of a modified polyurethane cable used in new energy vehicles and a preparation method thereof. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] The embodiment of the present invention provides a modified polyurethane cable applied to new energy vehicles and a preparation method thereof, the method mainly comprising the following steps:

[0038] S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0039] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0040] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0041] S4. Prepare the inner flame retardant in three steps according to the process formula;

[0042] S5. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0043] As an embodiment, the following content of the embodiments of the present invention gives several specific examples of the aforementioned modified polyurethane cable applied to new energy vehicles and its preparation method, such as Example 1, Example 2, Example 3 and Examples 1-7 for comparison and explanation.

[0044] Embodiment 1:

[0045] S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0046] The inner layer raw materials include: 80 parts of polyether polyol, 0.4 parts of deionized water, 0.1 parts of dibutyltin, 0.4 parts of triethylamine, 1 part of silicone glycol copolymer, 120 parts of 4,4-diphenylmethane diisocyanate, and 5 parts of inner layer flame retardant;

[0047] The outer layer raw materials include: 50 parts of thermoplastic polyurethane elastomer, 30 parts of styrene-ethylene-butadiene-styrene block copolymer, 6 parts of naphthenic oil, 50 parts of outer layer flame retardant, 8 parts of silicon dioxide, 1 part of zinc stearate, 1 part of pentaerythritol ester, and 3 parts of porous alumina;

[0048] Middle foaming layer raw materials: 20 parts of plastic polyurethane elastomer, 10 parts of styrene-ethylene-butadiene-styrene block copolymer, 2 parts of naphthenic oil, 15 parts of outer layer flame retardant, 3 parts of silicon dioxide, 0.3 parts of zinc stearate, 0.3 parts of pentaerythritol ester, 1 part of porous alumina;

[0049] The inner flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine, and triethylamine in a ratio of 1:200:0.5:40;

[0050] The outer flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:10;

[0051] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0052] Step 1: Use a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain an outer flame retardant, the ball milling speed is 100 rpm, and the ball milling time is 100 min;

[0053] Step 2: Stir the styrene-ethylene-butadiene-styrene block copolymer, add cyclohexane oil dropwise during the stirring process and continue stirring for 15 minutes;

[0054] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 30 minutes to mix the raw materials evenly;

[0055] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer. The processing temperature is 160° C., the screw speed is 100 rpm, and the processing time is 30 min.

[0056] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0057] Step 1: Repeat the process from step 1 to step 4 in S2 to prepare an intermediate polyurethane layer;

[0058] Step 2: The middle polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 120°C, the pressure is 20MPa, and the time is 1h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed to a thickness of 1mm to obtain the middle foaming layer;

[0059] Step 3: Use polyurethane glue to bond the middle foaming layer to the outer polyurethane layer;

[0060] S4. Prepare the inner flame retardant in three steps according to the process formula;

[0061] Step 1: Take 70% of the total chloroform solution and disperse the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0062] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0063] Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 50°C under nitrogen protection, stir for 15 hours, cool to room temperature, filter, wash and dry to obtain the inner flame retardant;

[0064] S5. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0065] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer, and inner flame retardant at a stirring speed of 100 rpm for 30 minutes;

[0066] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 30 seconds at a speed of 300 rpm;

[0067] Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S3 and scrape it flat with a scraping thickness of 3 mm. Curing it at 60°C for 120 hours obtains the desired modified polyurethane cable material.

[0068] Embodiment 2:

[0069] S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0070] The inner layer raw materials include: 100 parts of polyether polyol, 0.7 parts of deionized water, 0.4 parts of dibutyltin, 0.6 parts of triethylamine, 4 parts of silicone glycol copolymer, 160 parts of 4,4-diphenylmethane diisocyanate, and 10 parts of inner layer flame retardant;

[0071] The outer layer raw materials include: 100 parts of thermoplastic polyurethane elastomer, 30-80 parts of styrene-ethylene-butadiene-styrene block copolymer, 20 parts of naphthenic oil, 70 parts of outer layer flame retardant, 15 parts of silicon dioxide, 3 parts of zinc stearate, 3 parts of pentaerythritol ester, and 6 parts of porous alumina;

[0072] Middle foaming layer raw materials: 40 parts of plastic polyurethane elastomer, 30 parts of styrene-ethylene-butadiene-styrene block copolymer, 8 parts of naphthenic oil, 25 parts of outer layer flame retardant, 5 parts of silicon dioxide, 1 part of zinc stearate, 1 part of pentaerythritol ester, 2 parts of porous alumina;

[0073] The inner flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine and triethylamine in a ratio of 1:400:1.5:60;

[0074] The outer flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:30;

[0075] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0076] Step 1: Use a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain an outer flame retardant, the ball milling speed is 300 rpm, and the ball milling time is 200 min;

[0077] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 30 minutes;

[0078] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 60 minutes to mix the raw materials evenly;

[0079] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer, the processing temperature is 200°C, the screw speed is 600rpm, and the processing time is 120min;

[0080] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0081] Step 1: Repeat the process from step 1 to step 4 in S2 to prepare an intermediate polyurethane layer;

[0082] Step 2: The middle polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 160°C, the pressure is 25MPa, and the time is 4h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed to a thickness of 3mm to obtain the middle foaming layer;

[0083] Step 3: Use polyurethane glue to bond the middle foaming layer to the outer polyurethane layer;

[0084] S4. Prepare the inner flame retardant in three steps according to the process formula;

[0085] Step 1: Take 90% of the total chloroform solution and disperse the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0086] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0087] Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 70°C under nitrogen protection, stir for 20 hours, cool to room temperature, filter, wash and dry to obtain the inner flame retardant;

[0088] S5. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0089] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer and inner flame retardant at a stirring speed of 200 rpm for 60 minutes;

[0090] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 60 seconds at a speed of 400 rpm;

[0091] Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S3 and scrape it flat with a scraping thickness of 5 mm. Curing it at 80°C for 140 hours obtains the desired modified polyurethane cable material.

[0092] Embodiment 3:

[0093] S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0094] The inner layer raw materials include: 90 parts of polyether polyol, 0.6 parts of deionized water, 0.3 parts of dibutyl ditin, 0.5 parts of triethylamine, 3 parts of silicone glycol copolymer, 140 parts of 4,4-diphenylmethane diisocyanate, and 8 parts of inner layer flame retardant;

[0095] The outer layer raw materials include: 70 parts of thermoplastic polyurethane elastomer, 60 parts of styrene-ethylene-butadiene-styrene block copolymer, 10 parts of naphthenic oil, 60 parts of outer layer flame retardant, 12 parts of silicon dioxide, 2 parts of zinc stearate, 2 parts of pentaerythritol ester, and 4 parts of porous alumina;

[0096] Middle foaming layer raw materials: 30 parts of plastic polyurethane elastomer, 20 parts of styrene-ethylene-butadiene-styrene block copolymer, 6 parts of naphthenic oil, 20 parts of outer layer flame retardant, 4 parts of silicon dioxide, 0.7 parts of zinc stearate, 0.7 parts of pentaerythritol ester, 1 part of porous alumina;

[0097] The inner flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine, and triethylamine in a ratio of 1:300:1:50;

[0098] The outer flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:20;

[0099] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0100] Step 1: Use a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain an outer flame retardant, the ball milling speed is 200 rpm, and the ball milling time is 150 min;

[0101] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 20 minutes;

[0102] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 40 minutes to mix the raw materials evenly;

[0103] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer. The processing temperature is 180°C, the screw speed is 300rpm, and the processing time is 80min.

[0104] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0105] Step 1: Repeat the process from step 1 to step 4 in S2 to prepare an intermediate polyurethane layer;

[0106] Step 2: The middle polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 140°C, the pressure is 22MPa, and the time is 3h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed to a thickness of 2mm to obtain the middle foaming layer;

[0107] Step 3: Use polyurethane glue to bond the middle foaming layer to the outer polyurethane layer;

[0108] S4. Prepare the inner flame retardant in three steps according to the process formula;

[0109] Step 1: Take 80% of the total chloroform solution and disperse the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0110] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0111] Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 60°C under nitrogen protection, stir for 17 hours, cool to room temperature, filter, wash and dry to obtain the inner flame retardant;

[0112] S5. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0113] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer, and inner flame retardant at a stirring speed of 150 rpm for 40 minutes;

[0114] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 50 seconds at a speed of 350 rpm;

[0115] Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S3 and scrape it flat with a scraping thickness of 4 mm. Curing it at 70°C for 130 hours obtains the desired modified polyurethane cable material.

[0116] Comparative Example 1:

[0117] S1. Prepare the modified polyurethane layer raw materials according to the mass ratio;

[0118] The outer layer raw materials include: 70 parts of thermoplastic polyurethane elastomer, 60 parts of styrene-ethylene-butadiene-styrene block copolymer, 10 parts of naphthenic oil, 60 parts of outer layer flame retardant, 12 parts of silicon dioxide, 2 parts of zinc stearate, 2 parts of pentaerythritol ester, and 4 parts of porous alumina;

[0119] The flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:20;

[0120] S2. Prepare modified polyurethane cable in four steps according to the process formula;

[0121] The first step: using a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain a flame retardant, the ball milling speed is 200 rpm, and the ball milling time is 150 min;

[0122] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 20 minutes;

[0123] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 40 minutes to mix the raw materials evenly;

[0124] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain a modified polyurethane cable material. The processing temperature is 180° C., the screw speed is 300 rpm, and the processing time is 80 min.

[0125] Comparative Example 2:

[0126] S1. Prepare the modified polyurethane layer raw materials according to the mass ratio;

[0127] The inner layer raw materials include: 90 parts of polyether polyol, 0.6 parts of deionized water, 0.3 parts of dibutyl ditin, 0.5 parts of triethylamine, 3 parts of silicone glycol copolymer, 140 parts of 4,4-diphenylmethane diisocyanate, and 8 parts of inner layer flame retardant;

[0128] The flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine, and triethylamine in a ratio of 1:300:1:50;

[0129] S2. Prepare the flame retardant in three steps according to the process formula;

[0130] Step 1: Take 80% of the total chloroform solution and disperse the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0131] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0132] Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 60°C under nitrogen protection, stir for 17 hours, cool to room temperature, filter, wash and dry to obtain a flame retardant;

[0133] S3. A modified polyurethane cable material is prepared in three steps according to the process formula;

[0134] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer, and inner flame retardant at a stirring speed of 150 rpm for 40 minutes;

[0135] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 50 seconds at a speed of 350 rpm;

[0136] Step 3: Immediately apply the mixture obtained in the second step to the surface of the base film and scrape it flat with a scraping thickness of 4 mm. Curing it at 70°C for 130 hours to obtain the desired modified polyurethane cable material.

[0137] Comparative Example 3:

[0138] S1. Configure the outer layer and the foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0139] The outer layer raw materials include: 70 parts of thermoplastic polyurethane elastomer, 60 parts of styrene-ethylene-butadiene-styrene block copolymer, 10 parts of naphthenic oil, 60 parts of outer layer flame retardant, 12 parts of silicon dioxide, 2 parts of zinc stearate, 2 parts of pentaerythritol ester, and 4 parts of porous alumina;

[0140] Foaming layer raw materials: 30 parts of plastic polyurethane elastomer, 20 parts of styrene-ethylene-butadiene-styrene block copolymer, 6 parts of naphthenic oil, 20 parts of outer layer flame retardant, 4 parts of silicon dioxide, 0.7 parts of zinc stearate, 0.7 parts of pentaerythritol ester, 1 part of porous alumina;

[0141] The flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:20;

[0142] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0143] The first step: using a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain a flame retardant, the ball milling speed is 200 rpm, and the ball milling time is 150 min;

[0144] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 20 minutes;

[0145] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 40 minutes to mix the raw materials evenly;

[0146] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer. The processing temperature is 180°C, the screw speed is 300rpm, and the processing time is 80min.

[0147] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0148] Step 1: Repeat the process from step 1 to step 4 in S2 to prepare a polyurethane layer;

[0149] Step 2: The polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 140°C, the pressure is 22MPa, and the time is 3h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed to a thickness of 2mm to obtain a foaming layer;

[0150] Step 3: Use polyurethane glue to bond the foaming layer and the outer polyurethane layer to modify the polyurethane cable material.

[0151] Comparative Example 4:

[0152] S1. Configure the inner layer and the foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0153] The inner layer raw materials include: 90 parts of polyether polyol, 0.6 parts of deionized water, 0.3 parts of dibutyl ditin, 0.5 parts of triethylamine, 3 parts of silicone glycol copolymer, 140 parts of 4,4-diphenylmethane diisocyanate, and 8 parts of inner layer flame retardant;

[0154] Foaming layer raw materials: 30 parts of plastic polyurethane elastomer, 20 parts of styrene-ethylene-butadiene-styrene block copolymer, 6 parts of naphthenic oil, 20 parts of outer layer flame retardant, 4 parts of silicon dioxide, 0.7 parts of zinc stearate, 0.7 parts of pentaerythritol ester, 1 part of porous alumina;

[0155] The inner flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine, and triethylamine in a ratio of 1:300:1:50;

[0156] The flame retardant of the foaming layer is a mixture of expanded graphite and vermiculite powder, with a ratio of 1:20;

[0157] S2. Prepare the foaming layer polyurethane layer in five steps according to the process formula;

[0158] Step 1: Using a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain a foaming layer flame retardant, the ball milling speed is 200 rpm, and the ball milling time is 150 min;

[0159] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 20 minutes;

[0160] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 40 minutes to mix the raw materials evenly;

[0161] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain a foamed polyurethane layer, the processing temperature is 180° C., the screw speed is 300 rpm, and the processing time is 80 min;

[0162] Step 5: The polyurethane layer of the foaming layer in the fourth step is placed in a self-made high-pressure container, and the container temperature and pumping pressure, temperature and time are adjusted, wherein the temperature is 140°C, the pressure is 22MPa, and the time is 3h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed to a thickness of 2mm to obtain a foaming layer;

[0163] S3. Prepare the inner flame retardant in three steps according to the process formula;

[0164] Step 1: Take 80% of the total chloroform solution and disperse the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0165] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0166] Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 60°C under nitrogen protection, stir for 17 hours, cool to room temperature, filter, wash and dry to obtain the inner flame retardant;

[0167] S4. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0168] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer, and inner flame retardant at a stirring speed of 150 rpm for 40 minutes;

[0169] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 50 seconds at a speed of 350 rpm;

[0170] Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S2 and scrape it flat with a scraping thickness of 4 mm. Curing it at 70°C for 130 hours obtains the desired modified polyurethane cable material.

[0171] Comparative Example 5:

[0172] S1. Configure the inner layer and outer layer modified polyurethane layer raw materials according to the mass ratio;

[0173] The inner layer raw materials include: 90 parts of polyether polyol, 0.6 parts of deionized water, 0.3 parts of dibutyl ditin, 0.5 parts of triethylamine, 3 parts of silicone glycol copolymer, 140 parts of 4,4-diphenylmethane diisocyanate, and 8 parts of inner layer flame retardant;

[0174] The outer layer raw materials include: 70 parts of thermoplastic polyurethane elastomer, 60 parts of styrene-ethylene-butadiene-styrene block copolymer, 10 parts of naphthenic oil, 60 parts of outer layer flame retardant, 12 parts of silicon dioxide, 2 parts of zinc stearate, 2 parts of pentaerythritol ester, and 4 parts of porous alumina;

[0175] The inner flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine, and triethylamine in a ratio of 1:300:1:50;

[0176] The outer flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:20;

[0177] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0178] Step 1: Use a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain an outer flame retardant, the ball milling speed is 200 rpm, and the ball milling time is 150 min;

[0179] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 20 minutes;

[0180] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 40 minutes to mix the raw materials evenly;

[0181] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer. The processing temperature is 180°C, the screw speed is 300rpm, and the processing time is 80min.

[0182] S3. Prepare the inner flame retardant in three steps according to the process formula;

[0183] Step 1: Take 80% of the total chloroform solution and disperse the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0184] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0185] Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 60°C under nitrogen protection, stir for 17 hours, cool to room temperature, filter, wash and dry to obtain the inner flame retardant;

[0186] S4. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0187] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer, and inner flame retardant at a stirring speed of 150 rpm for 40 minutes;

[0188] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 50 seconds at a speed of 350 rpm;

[0189] Step 3: Immediately apply the mixture obtained in the second step to the surface of the outer polyurethane layer of S2 and scrape it flat with a scraping thickness of 4 mm. Curing it at 70°C for 130 hours obtains the desired modified polyurethane cable material.

[0190] Comparative Example 6:

[0191] S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0192] The inner layer raw materials include: 90 parts of polyether polyol, 0.6 parts of deionized water, 0.3 parts of dibutyl ditin, 0.5 parts of triethylamine, 3 parts of silicone glycol copolymer, and 140 parts of 4,4-diphenylmethane diisocyanate;

[0193] The outer layer raw materials include: 70 parts of thermoplastic polyurethane elastomer, 60 parts of styrene-ethylene-butadiene-styrene block copolymer, 10 parts of naphthenic oil, 60 parts of outer layer flame retardant, 12 parts of silicon dioxide, 2 parts of zinc stearate, 2 parts of pentaerythritol ester, and 4 parts of porous alumina;

[0194] Middle foaming layer raw materials: 30 parts of plastic polyurethane elastomer, 20 parts of styrene-ethylene-butadiene-styrene block copolymer, 6 parts of naphthenic oil, 20 parts of outer layer flame retardant, 4 parts of silicon dioxide, 0.7 parts of zinc stearate, 0.7 parts of pentaerythritol ester, 1 part of porous alumina;

[0195] The outer flame retardant is a mixture of expanded graphite and vermiculite powder in a ratio of 1:20;

[0196] S2. The outer polyurethane layer is prepared in four steps according to the process formula;

[0197] Step 1: Use a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain an outer flame retardant, the ball milling speed is 200 rpm, and the ball milling time is 150 min;

[0198] Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 20 minutes;

[0199] Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 40 minutes to mix the raw materials evenly;

[0200] Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer. The processing temperature is 180°C, the screw speed is 300rpm, and the processing time is 80min.

[0201] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0202] Step 1: Repeat the process from step 1 to step 4 in S2 to prepare an intermediate polyurethane layer;

[0203] Step 2: The middle polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 140°C, the pressure is 22MPa, and the time is 3h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed to a thickness of 2mm to obtain the middle foaming layer;

[0204] Step 3: Use polyurethane glue to bond the middle foaming layer to the outer polyurethane layer;

[0205] S4. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0206] Step 1: mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine and silicone glycol copolymer at a stirring speed of 150 rpm for 40 minutes;

[0207] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 50 seconds at a speed of 350 rpm;

[0208] Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S3 and scrape it flat with a scraping thickness of 4 mm. Curing it at 70°C for 130 hours obtains the desired modified polyurethane cable material.

[0209] Comparative Example 7:

[0210] S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio;

[0211] The inner layer raw materials include: 90 parts of polyether polyol, 0.6 parts of deionized water, 0.3 parts of dibutyl ditin, 0.5 parts of triethylamine, 3 parts of silicone glycol copolymer, 140 parts of 4,4-diphenylmethane diisocyanate, and 8 parts of inner layer flame retardant;

[0212] The outer layer raw materials include: 70 parts of thermoplastic polyurethane elastomer, 60 parts of styrene-ethylene-butadiene-styrene block copolymer, 10 parts of naphthenic oil, 12 parts of silicon dioxide, 2 parts of zinc stearate, 2 parts of pentaerythritol ester, and 4 parts of porous alumina;

[0213] Middle foaming layer raw materials: 30 parts of plastic polyurethane elastomer, 20 parts of styrene-ethylene-butadiene-styrene block copolymer, 6 parts of naphthenic oil, 4 parts of silicon dioxide, 0.7 parts of zinc stearate, 0.7 parts of pentaerythritol ester, 1 part of porous alumina;

[0214] The inner flame retardant is a reactant of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine, and triethylamine in a ratio of 1:300:1:50;

[0215] S2. The outer polyurethane layer is prepared in three steps according to the process formula;

[0216] The first step is to stir the styrene-ethylene-butadiene-styrene block copolymer, add cyclohexane oil dropwise during the stirring process and continue stirring for 20 minutes;

[0217] Step 2: Add the plastic polyurethane elastomer, styrene-ethylene-butadiene-styrene block copolymer, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the stirrer in the second step and continue stirring for 40 minutes to mix the raw materials evenly;

[0218] Step 3: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer, the processing temperature is 180°C, the screw speed is 300rpm, and the processing time is 80min;

[0219] S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding;

[0220] Step 1: Repeat the process from step 1 to step 4 in S2 to prepare an intermediate polyurethane layer;

[0221] Step 2: The middle polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 140°C, the pressure is 22MPa, and the time is 3h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed to a thickness of 2mm to obtain the middle foaming layer;

[0222] Step 3: Use polyurethane glue to bond the middle foaming layer to the outer polyurethane layer;

[0223] S4. Prepare the inner flame retardant in three steps according to the process formula;

[0224] Step 1: Take 80% of the total chloroform solution and disperse the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension;

[0225] Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution;

[0226] Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 60°C under nitrogen protection, stir for 17 hours, cool to room temperature, filter, wash and dry to obtain the inner flame retardant;

[0227] S5. The inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material;

[0228] Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer, and inner flame retardant at a stirring speed of 150 rpm for 40 minutes;

[0229] Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 50 seconds at a speed of 350 rpm;

[0230] Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S3 and scrape it flat with a scraping thickness of 4 mm. Curing it at 70°C for 130 hours obtains the desired modified polyurethane cable material.

[0231] Tensile strength test:

[0232] Tensile strength is the resistance to the maximum uniform plastic deformation of the material. Before the tensile specimen is subjected to the maximum tensile stress, the deformation is uniform and consistent, but after exceeding the maximum tensile stress, the metal begins to shrink, that is, concentrated deformation occurs; for brittle materials with no (or very small) uniform plastic deformation, it reflects the fracture resistance of the material. The test standard can refer to the national standard GB / T228-1987), the unit is MPa;

[0233] Elongation after break:

[0234] It refers to the percentage of the elongated length of the specimen to the original length when the material breaks under the action of external force (tension). The test standard can refer to the national standard GB / T 528-2009.

[0235] Table 1

[0236]

[0237] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A modified polyurethane cable for use in new energy vehicles and a preparation method thereof, characterized in that: The steps include: S1. Configure the inner layer, outer layer, and intermediate foaming layer modified polyurethane layer raw materials according to the mass ratio; S2. The outer polyurethane layer is prepared in four steps according to the process formula; S3 prepared according to the process formula of the intermediate foam layer and S2 outer polyurethane layer bonding; S4. Prepare the inner flame retardant in three steps according to the process formula; S5. Prepare an inner flame retardant layer in three steps according to the process formula and coat it on the surface of the foaming layer in S3 to obtain a modified polyurethane cable material.

2. The preparation method according to claim 1, characterized in that: In step S1, the modified polyurethane cable consists of an inner layer, an outer layer, and a middle foaming layer.

3. The preparation method according to claim 1, characterized in that: In step S1, the inner layer raw materials include: 80-100 parts of polyether polyol, 0.4-0.7 parts of deionized water, 0.1-0.4 parts of dibutyltin, 0.4-0.6 parts of triethylamine, 1-4 parts of silicone glycol copolymer, 120-160 parts of 4,4-diphenylmethane diisocyanate, and 5-10 parts of inner layer flame retardant.

4. The preparation method according to claim 1, characterized in that: In step S1, the outer layer raw materials include: 50-100 parts of thermoplastic polyurethane elastomer, 30-80 parts of styrene-ethylene-butadiene-styrene block copolymer, 6-20 parts of cyclohexane oil, 50-70 parts of outer layer flame retardant, 8-15 parts of silica, 1-3 parts of zinc stearate, 1-3 parts of pentaerythritol ester, and 3-6 parts of porous alumina.

5. The preparation method according to claim 3, characterized in that: The raw materials of the inner layer flame retardant include reactants of amino silicon dioxide, trichloromethane, dipalmitoylphosphatidylcholine and triethylamine, and the ratio is 1:200-400:0.5-1.5:40-60.

6. The preparation method according to claim 4, characterized in that: The outer layer flame retardant raw materials include: a mixture of expanded graphite and vermiculite powder, with a ratio of 1:10-30.

7. The preparation method according to claim 1, characterized in that: In step S2, the outer polyurethane layer is prepared in four steps according to the process formula, including: The first step: using a horizontal ball mill to mix expanded graphite and vermiculite powder to obtain an outer flame retardant, the ball milling speed is 100-300rpm, and the ball milling time is 100-200min; Step 2: Stirring the styrene-ethylene-butadiene-styrene block copolymer, dropping cyclohexane oil during the stirring process and continuing stirring for 15-30 minutes; Step 3: Add the plastic polyurethane elastomer, outer flame retardant, silicon dioxide, zinc stearate, pentaerythritol ester, and porous alumina into the agitator in the second step and continue to stir for 30-60 minutes to mix the raw materials evenly; Step 4: Add the raw materials mixed evenly in the third step into a twin-screw extruder and extrude to obtain an outer polyurethane layer. The processing temperature is 160-200° C., the screw speed is 100-600 rpm, and the processing time is 30-120 min.

8. The preparation method according to claim 1, characterized in that: In step S3, the middle foaming layer is prepared according to the process formula and bonded to the outer polyurethane layer in S2, including: Step 1: Repeat the process from step 1 to step 4 in S2 to prepare an intermediate polyurethane layer; Step 2: The middle polyurethane layer in the first step is placed in a self-made high-pressure container, and the container temperature and pump pressure, temperature and time are adjusted, wherein the temperature is 120-160°C, the pressure is 20-25MPa, and the time is 1-4h. After the foaming time, the pressure is quickly released, and the foaming layer is cooled and formed, and the thickness is 1-3mm to obtain the middle foaming layer; Step 3: Use polyurethane glue to bond the middle foam layer to the outer polyurethane layer.

9. The preparation method according to claim 1, characterized in that: In step S4, the inner layer flame retardant is prepared in three steps according to the process formula, including: The first step: taking 70%-90% of the total chloroform solution, dispersing the amino silicon dioxide in the chloroform by ultrasonic stirring to form a white suspension; Step 2: dissolving dipalmitoylphosphatidylcholine in the remaining chloroform, and then dropping it into the dispersion in the first step to obtain a mixed solution; Step 3: Add triethylamine solution to the mixed solution in step 2, then heat to 50-70°C under nitrogen protection, stir for 15-20h, cool to room temperature, filter, wash and dry to obtain the inner flame retardant.

10. The preparation method according to claim 1, characterized in that: In step S5, the inner flame retardant layer is prepared in three steps according to the process formula and coated on the surface of the foaming layer in S3 to obtain the modified polyurethane cable material, which includes: Step 1: Mechanically stir and mix polyether polyol, distilled water, dibutyltin, triethylamine, silicone glycol copolymer and inner flame retardant at a stirring speed of 100-200 rpm for 30-60 minutes; Step 2: Add 4,4-diphenylmethane diisocyanate to the mixture obtained by stirring in the first step, and continue mechanical stirring for 30-60 seconds at a speed of 300-400 rpm; Step 3: Immediately apply the mixture obtained in the second step to the surface of the foaming layer in S3 and scrape it flat with a scraping thickness of 3-5 mm. Curing it at 60-80°C for 120-140h to obtain the desired modified polyurethane cable material.

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