Automobile wire harness film containing environment-friendly flame retardant and preparation method of automobile wire harness film

Abstract

The invention relates to the field of wire harness films, and discloses an automobile wire harness film containing an environment-friendly flame retardant and a preparation method thereof.The wire harness film is prepared from polyvinyl chloride resin, a calcium-zinc stabilizer, an antioxidant tetra [beta-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester, an antioxidant tris (2, 2, 6-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5-trimethyl-1, 3, 5- The high-temperature-resistant plastic is prepared from 2, 4-di-tert-butylphenyl) ester, polyethylene wax, acetyl tributyl citrate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride grafted ethylene-vinyl acetate and toner. The modified aluminum hydroxide is prepared from gamma-aminopropyltriethoxysilane, an ethanol water solution, acetic acid and powdery aluminum hydroxide. The flame-retardant insulating material has relatively good flame retardance, insulating property and mechanical property.

Description

Technical Field

[0001] This invention relates to the field of wire harness films, and more specifically to an automotive wire harness film containing an environmentally friendly flame retardant and its preparation method. Background Technology

[0002] Wire harness film is a widely used coating material in the automotive, electronics, and electrical appliance industries. Its main functions are to bundle, insulate, and flame-retardant protect wire and cable bundles. With increasingly stringent safety and environmental protection requirements in these industries, stricter demands are being placed on the flame-retardant properties, mechanical strength, and environmental friendliness of wire harness film. Currently, most mainstream products use polyvinyl chloride (PVC) as the base resin and add various flame retardants, plasticizers, and stabilizers to meet basic performance requirements.

[0003] Chinese patent CN118791978B discloses an automotive wiring harness tape and its preparation method. The tape consists of a shielding layer and a coating layer. The shielding layer is made from raw materials such as polyester fiber, nylon fiber, glass fiber, carbon fiber, and conductive composite fiber, exhibiting excellent electromagnetic shielding capabilities. The coating layer is formed by mixing antioxidants, light stabilizers, and silicone rubber, effectively reducing the tape's VOC emissions while ensuring good aging resistance and mechanical properties. The preparation method includes steps such as fiber mixing, heat setting treatment, coating layer preparation, and cutting. Precise control of the component ratios and process parameters ensures the tape's continuity and stability. However, this solution lacks flame-retardant design, failing to meet the automotive industry's high requirements for flame retardancy. Summary of the Invention

[0004] The purpose of this invention is to provide an automotive wiring harness film containing an environmentally friendly flame retardant and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an automotive wiring harness film containing an environmentally friendly flame retardant, wherein the wiring harness film is prepared from polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate, and colorant; wherein the modified aluminum hydroxide is prepared from γ-aminopropyltriethoxysilane, an aqueous solution of ethanol, acetic acid, and powdered aluminum hydroxide.

[0006] Furthermore, the mass ratio of γ-aminopropyltriethoxysilane, aqueous ethanol solution, and powdered aluminum hydroxide is (0.5-1.0):(10-20):(8-12).

[0007] Furthermore, the mass ratio of polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate ester, and pigment is 100:(2-4):(0.1-0.2):(0.1-0.2):(0.4-0.6):(30-40):(9-11):(12-18):(4-6):(1-3).

[0008] Furthermore, the particle size of the powdered aluminum hydroxide is 1.0-2.0 μm.

[0009] Furthermore, a method for preparing an automotive wiring harness film containing an environmentally friendly flame retardant includes the following steps: (1) Mix γ-aminopropyltriethoxysilane with an aqueous ethanol solution, adjust the pH value with acetic acid, and stir for 30-50 minutes at 200-300 rpm and 50-70°C to obtain a silane hydrolysate; add powdered aluminum hydroxide and the above silane hydrolysate into a mixer, stir for 1-1.4 hours at 50-60°C and 200-300 rpm, and vacuum dry at 70-80°C for 4-6 hours to obtain modified aluminum hydroxide; (2) Mix one-quarter of the total mass of polyvinyl chloride resin with a degree of polymerization ranging from 1200 to 1400, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax with a molecular weight of 2000 to 3000, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate with a degree of polymerization of 2000 to 3000, maleic anhydride-grafted ethylene-vinyl acetate with a grafting rate of 0.6% to 1.4%, and color powder for 10 to 15 minutes to obtain a premix. (3) Add the premix obtained in step (2) into a co-rotating twin-screw extruder. After the extruded strip is cooled in a water bath at 25-30℃, it is cut into pellets to obtain granules. (4) The granules obtained in step (3) are mixed with the remaining polyvinyl chloride resin and then fed into a single screw extruder. The melt is cast through a T-die to a cooling roller at 20-30°C to form a wire harness film.

[0010] Furthermore, the mass fraction of the ethanol aqueous solution in step (1) is 70-80%.

[0011] Furthermore, in step (1), the pH value is adjusted to 5.5-6.0 using acetic acid.

[0012] Furthermore, in step (2), the mixing speed is 900-1100 rpm.

[0013] Furthermore, in step (3), the temperature of the co-rotating twin-screw extruder is set to 145-155℃ in zone 1, 160-170℃ in zone 2, 170-175℃ in zone 3, 175-180℃ in zone 4, and 175-180℃ in zone 5, the die head temperature is 175-180℃, the screw speed is 200-300rpm, and the length-to-diameter ratio is 38-40:1.

[0014] Furthermore, in step (4), the temperature of the single screw extruder is set to 150-160℃ in zone 1, 160-170℃ in zone 2, 170-180℃ in zone 3, and 175-185℃ in zone 4, the die temperature is 180-190℃, and the length-to-diameter ratio is 28-30:1.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. This invention uses γ-aminopropyltriethoxysilane to surface-treat aluminum hydroxide filler. γ-aminopropyltriethoxysilane hydrolyzes in acidic ethanol aqueous solution to generate silanol. The silanol undergoes a condensation reaction with the hydroxyl groups on the surface of aluminum hydroxide to form covalent bonds, thereby improving the interfacial compatibility between aluminum hydroxide and polyvinyl chloride (PVC) and reducing phase separation between the inorganic filler and the organic polymer. PVC resin serves as the matrix material, providing film-forming properties and mechanical strength. Tributyl acetylacetonate, as an environmentally friendly plasticizer, reduces intermolecular forces in PVC molecules and improves flexibility. Calcium-zinc stabilizers inhibit catalytic degradation by capturing hydrogen chloride produced during PVC decomposition. Antioxidants block thermal oxidative free radical chain reactions. Polyethylene wax, as a lubricant, reduces processing energy consumption and improves melt flowability. The surface-treated aluminum hydroxide... A synergistic flame-retardant system is formed with ammonium polyphosphate. During combustion, ammonium polyphosphate decomposes upon heating to generate polyphosphoric acid, promoting the dehydration and char formation of the substrate. Aluminum hydroxide decomposes, absorbs heat, and releases water vapor to dilute combustible gases. The two work synergistically to form a dense char layer that isolates heat and oxygen. Maleic anhydride-grafted ethylene-vinyl acetate acts as a reactive compatibilizer. Its maleic anhydride groups react chemically with the amino groups on the surface of silane-modified aluminum hydroxide to form amide bonds. Maleic anhydride-grafted ethylene-vinyl acetate also has good compatibility with polyvinyl chloride matrix. This invention provides mechanical support and electrical insulation properties through the continuous phase of polyvinyl chloride. Modified aluminum hydroxide and ammonium polyphosphate act as environmentally friendly flame retardants, forming a dense char layer during combustion to effectively block heat transfer and combustible gas diffusion. Interface reinforcement binds the filler to the matrix to prevent the migration of flame retardants. Detailed Implementation

[0016] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0017] An automotive wiring harness film containing an environmentally friendly flame retardant is provided, wherein the wiring harness film is prepared from polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetylacetate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate, and colorant; wherein the modified aluminum hydroxide is prepared from γ-aminopropyltriethoxysilane, aqueous ethanol solution, acetic acid, and powdered aluminum hydroxide.

[0018] For experiments not specifically described in the examples, the procedures and conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagents. Calcium and zinc stabilizers were purchased from Shandong Zhongli Petrochemical Technology Co., Ltd. Color powder was purchased from Shandong Jincaiyang New Material Technology Co., Ltd.

[0019] Example 1:

[0020] (1) Mix γ-aminopropyltriethoxysilane with a 70% ethanol aqueous solution, adjust the pH to 5.5 with acetic acid, and stir for 30 minutes at 200 rpm and 50°C to obtain a silane hydrolysate; add powdered aluminum hydroxide with a particle size of 1.0 μm and the above silane hydrolysate into a mixer, stir for 1 hour at 50°C and 200 rpm, and vacuum dry at 70°C for 4 hours to obtain modified aluminum hydroxide; wherein, the mass ratio of γ-aminopropyltriethoxysilane, ethanol aqueous solution and powdered aluminum hydroxide is 0.5:10:8.

[0021] (2) Mix one-quarter of the total mass of polyvinyl chloride resin with a degree of polymerization range of 1200, calcium zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax with a molecular weight of 2000, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate with a degree of polymerization of 2000, maleic anhydride-grafted ethylene-vinyl acetate with a grafting rate of 0.6%, and color powder at a speed of 900 rpm for 10 minutes to obtain a premix. (3) The premix obtained in step (2) is added to a co-rotating twin-screw extruder. The temperature of the co-rotating twin-screw extruder is set to 145°C in zone 1, 160°C in zone 2, 170°C in zone 3, 175°C in zone 4, and 175°C in zone 5. The die head temperature is 175°C, the screw speed is 200 rpm, and the length-to-diameter ratio is 38:1. The extruded strip is cooled in a 25°C water bath and then cut into pellets to obtain granules. (4) The granules obtained in step (3) are mixed with the remaining polyvinyl chloride resin and then fed into a single-screw extruder. The temperature of the single-screw extruder is set to 150℃ in zone 1, 160℃ in zone 2, 170℃ in zone 3, and 175℃ in zone 4. The die temperature is 180℃ and the length-to-diameter ratio is 28:1. The melt is cast through a T-die to a cooling roller at 20℃ to form a wire harness film with a thickness of 0.2mm. The mass ratio of polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetylacetonate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate and pigment is 100:2:0.1:0.1:0.4:30:9:12:4:1.

[0022] Example 2:

[0023] (1) γ-aminopropyltriethoxysilane was mixed with an aqueous ethanol solution of 75% by mass, and the pH value was adjusted to 5.7 with acetic acid. The mixture was stirred at 250 rpm and 60°C for 40 minutes to obtain a silane hydrolysate. Powdered aluminum hydroxide with a particle size of 1.5 μm and the above silane hydrolysate were added to a mixer and stirred at 55°C and 250 rpm for 1.2 hours. The mixture was then vacuum dried at 75°C for 5 hours to obtain modified aluminum hydroxide. The mass ratio of γ-aminopropyltriethoxysilane, aqueous ethanol solution and powdered aluminum hydroxide was 0.75:15:10.

[0024] (2) Mix one-quarter of the total mass of polyvinyl chloride resin with a degree of polymerization range of 1300, calcium zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax with a molecular weight of 2500, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate with a degree of polymerization of 2500, maleic anhydride-grafted ethylene-vinyl acetate with a grafting rate of 1.0%, and color powder at a speed of 1000 rpm for 12.5 minutes to obtain a premix. (3) The premix obtained in step (2) is added to a co-rotating twin-screw extruder. The temperature of the co-rotating twin-screw extruder is set to 150°C in zone 1, 165°C in zone 2, 172.5°C in zone 3, 177.5°C in zone 4, and 177.5°C in zone 5. The die head temperature is 177.5°C, the screw speed is 250 rpm, and the length-to-diameter ratio is 39:1. The extruded strip is cooled in a 27°C water bath and then granulated to obtain pellets. (4) The granules obtained in step (3) are mixed with the remaining polyvinyl chloride resin and then fed into a single-screw extruder. The temperature of the single-screw extruder is set to 155℃ in zone 1, 165℃ in zone 2, 175℃ in zone 3, and 180℃ in zone 4. The die temperature is 185℃ and the length-to-diameter ratio is 29:1. The melt is cast through a T-die to a cooling roller at 25℃ to form a wire harness film with a thickness of 0.2mm. The mass ratio of polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetylacetate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate and pigment is 100:3:0.15:0.15:0.5:35:10:15:5:2.

[0025] Example 3:

[0026] (1) Mix γ-aminopropyltriethoxysilane with an 80% ethanol aqueous solution, adjust the pH to 6.0 with acetic acid, and stir at 300 rpm and 70°C for 50 minutes to obtain a silane hydrolysate; add powdered aluminum hydroxide with a particle size of 2.0 μm and the above silane hydrolysate into a mixer, stir at 60°C and 300 rpm for 1.4 hours, and vacuum dry at 80°C for 4-6 hours to obtain modified aluminum hydroxide; wherein, the mass ratio of γ-aminopropyltriethoxysilane, ethanol aqueous solution and powdered aluminum hydroxide is 1.0:20:12.

[0027] (2) Mix one-quarter of the total mass of polyvinyl chloride resin with a degree of polymerization range of 1400, calcium zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax with a molecular weight of 3000, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate with a degree of polymerization of 3000, maleic anhydride-grafted ethylene-vinyl acetate with a grafting rate of 1.4%, and color powder at a speed of 1100 rpm for 15 minutes to obtain a premix. (3) The premix obtained in step (2) is added to a co-rotating twin-screw extruder. The temperature of the co-rotating twin-screw extruder is set to 155°C in zone 1, 170°C in zone 2, 175°C in zone 3, 180°C in zone 4, and 180°C in zone 5. The die head temperature is 180°C, the screw speed is 300 rpm, and the length-to-diameter ratio is 40:1. The extruded strip is cooled in a 30°C water bath and then cut into pellets to obtain granules. (4) The granules obtained in step (3) are mixed with the remaining polyvinyl chloride resin and then fed into a single-screw extruder. The temperature of the single-screw extruder is set to 160℃ in zone 1, 170℃ in zone 2, 180℃ in zone 3, and 185℃ in zone 4. The die temperature is 190℃ and the length-to-diameter ratio is 30:1. The melt is cast through a T-die to a cooling roller at 30℃ to form a wire harness film with a thickness of 0.2mm. The mass ratio of polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetylacetonate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate and pigment is 100:4:0.2:0.2:0.6:40:11:18:6:3.

[0028] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that γ-aminopropyltriethoxysilane was not used to modify the powdered aluminum hydroxide.

[0029] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that ammonium polyphosphate is not added.

[0030] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that maleic anhydride-grafted ethylene-vinyl acetate is not added.

[0031] Vertical flammability rating is tested according to GB / T2408-2021.

[0032] Tensile strength was tested according to GB / T1040.3-2006.

[0033] Volume resistivity was tested according to GB / T31838.2-2019.

[0034] Table 1 below shows the performance analysis results of the embodiments and comparative examples of the present invention.

[0035] Table 1

[0036] Experimental data from the examples and comparative examples show that the present invention uses γ-aminopropyltriethoxysilane as a surface modifier for aluminum hydroxide filler. In acidic ethanol aqueous solution, it hydrolyzes to generate reactive silanol. The silanol undergoes a condensation reaction with the hydroxyl groups on the surface of aluminum hydroxide particles to form Si-O-Al covalent bonds, thereby introducing long organic amino chains onto the surface of aluminum hydroxide, effectively improving the dispersibility and interfacial compatibility of aluminum hydroxide in polyvinyl chloride. Furthermore, the use of ammonium polyphosphate and surface-modified aluminum hydroxide to form a synergistic flame-retardant system, during combustion, the ammonium polyphosphate decomposes upon heating to generate… The process involves the formation of polyphosphoric acid, which promotes the dehydration and carbonization of polyvinyl chloride. Simultaneously, aluminum hydroxide decomposes, absorbs heat, and releases water vapor to dilute combustible gases and oxygen, forming an expanded carbon layer on the material surface. This carbon layer effectively isolates heat transfer and interrupts the combustion cycle. Maleic anhydride-grafted ethylene-vinyl acetate is used as a reactive compatibilizer. The maleic anhydride groups on its molecular chain undergo an amidation reaction with the amino groups on the surface of silane-modified aluminum hydroxide to form chemical bonds. Maleic anhydride-grafted ethylene-vinyl acetate combines with the polyvinyl chloride molecular chain through entanglement and compatibility, enhancing the interfacial bonding force.

[0037] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. An automotive wiring harness film containing an environmentally friendly flame retardant, characterized in that, The wire harness film is made from polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate, and color powder; the modified aluminum hydroxide is made from γ-aminopropyltriethoxysilane, aqueous ethanol solution, acetic acid, and powdered aluminum hydroxide.

2. The automotive wiring harness film containing an environmentally friendly flame retardant according to claim 1, characterized in that: The mass ratio of γ-aminopropyltriethoxysilane, aqueous ethanol solution, and powdered aluminum hydroxide is (0.5-1.0):(10-20):(8-12).

3. The automotive wiring harness film containing an environmentally friendly flame retardant according to claim 2, characterized in that: The mass ratio of polyvinyl chloride resin, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate, maleic anhydride-grafted ethylene-vinyl acetate ester, and pigment is 100:(2-4):(0.1-0.2):(0.1-0.2):(0.4-0.6):(30-40):(9-11):(12-18):(4-6):(1-3).

4. The automotive wiring harness film containing an environmentally friendly flame retardant according to claim 3, characterized in that: The particle size of powdered aluminum hydroxide is 1.0-2.0 μm.

5. The method for preparing an automotive wiring harness film containing an environmentally friendly flame retardant according to claim 4, characterized in that, Includes the following steps: (1) Mix γ-aminopropyltriethoxysilane with an aqueous ethanol solution, adjust the pH value with acetic acid, and stir for 30-50 minutes at 200-300 rpm and 50-70°C to obtain a silane hydrolysate; add powdered aluminum hydroxide and the above silane hydrolysate into a mixer, stir for 1-1.4 hours at 50-60°C and 200-300 rpm, and vacuum dry at 70-80°C for 4-6 hours to obtain modified aluminum hydroxide; (2) Mix one-quarter of the total mass of polyvinyl chloride resin with a degree of polymerization ranging from 1200 to 1400, calcium-zinc stabilizer, antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], antioxidant tris(2,4-di-tert-butylphenyl) phosphite, polyethylene wax with a molecular weight of 2000 to 3000, tributyl acetyl citrate, modified aluminum hydroxide, ammonium polyphosphate with a degree of polymerization of 2000 to 3000, maleic anhydride-grafted ethylene-vinyl acetate with a grafting rate of 0.6% to 1.4%, and color powder for 10 to 15 minutes to obtain a premix. (3) Add the premix obtained in step (2) into a co-rotating twin-screw extruder. After the extruded strip is cooled in a water bath at 25-30℃, it is cut into pellets to obtain granules. (4) The granules obtained in step (3) are mixed with the remaining polyvinyl chloride resin and then fed into a single screw extruder. The melt is cast through a T-die to a cooling roller at 20-30°C to form a wire harness film.

6. The method for preparing an automotive wiring harness film containing an environmentally friendly flame retardant according to claim 5, characterized in that: In step (1), the mass fraction of the ethanol aqueous solution is 70-80%.

7. The method for preparing an automotive wiring harness film containing an environmentally friendly flame retardant according to claim 5, characterized in that: In step (1), the pH value is adjusted to 5.5-6.0 using acetic acid.

8. The method for preparing an automotive wiring harness film containing an environmentally friendly flame retardant according to claim 5, characterized in that: In step (2), the mixing speed is 900-1100 rpm.

9. The method for preparing an automotive wiring harness film containing an environmentally friendly flame retardant according to claim 5, characterized in that: The temperature settings of the co-rotating twin-screw extruder in step (3) are 145-155℃ in zone 1, 160-170℃ in zone 2, 170-175℃ in zone 3, 175-180℃ in zone 4, and 175-180℃ in zone 5, with a die head temperature of 175-180℃, a screw speed of 200-300 rpm, and a length-to-diameter ratio of 38-40:

1.

10. The method for preparing an automotive wiring harness film containing an environmentally friendly flame retardant according to claim 5, characterized in that: In step (4), the temperature of the single screw extruder is set to 150-160℃ in zone 1, 160-170℃ in zone 2, 170-180℃ in zone 3, and 175-185℃ in zone 4, the die temperature is 180-190℃, and the length-to-diameter ratio is 28-30:1.

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