High-flame-retardant environment-friendly automobile thermal insulation material and preparation method thereof

Abstract

The invention relates to the field of thermal insulation materials, and particularly provides a high-flame-retardant environment-friendly automobile thermal insulation material and a preparation method thereof. The material is prepared by taking low-density polyethylene and a polyolefin elastomer as main bodies and matching with a foaming system agent and a flame-retardant system agent. The core advantage of the composite material is that on the basis of keeping excellent heat insulation, water resistance, corrosion resistance and mechanical strength, the performance contradiction in traditional materials is effectively balanced, the requirements of high flame retardance and environmental protection are successfully considered, and the requirement of the materials for environmental protection is greatly met. Due to the improvement of the comprehensive performance, the heat aging resistance, the service life and the long-term use stability of the material are remarkably enhanced, and the problem that the functions of heat insulation, water resistance and the like of a traditional material are easily attenuated along with time is effectively solved, so that the comprehensive performance of the material is particularly suitable for being popularized and used on public transport vehicles and even other public transport means.

Description

Technical Field

[0001] This application relates to the field of thermal insulation materials, and more specifically mentions a high flame-retardant and environmentally friendly automotive thermal insulation material and its preparation method. Background Technology

[0002] With increasing global focus on environmental protection and energy efficiency, emerging environmental protection industries, especially in the new energy vehicle sector, are seeking more efficient and environmentally friendly materials to replace traditional insulation materials. Cross-linked polyethylene (XPE), as a novel environmentally friendly insulation material, has been widely used in the automotive industry due to its excellent physical properties and chemical stability. However, to meet more stringent fire safety standards and improve insulation performance, developing XPE materials with higher flame retardancy and better insulation effects has become a current research hotspot.

[0003] Existing XPE materials, due to their lightweight, sound insulation, shock absorption, and moisture-proof properties, have been widely used as automotive floor mats, headliners, door panel filling layers, and seat insulation layers. Their closed-cell structure can effectively block heat transfer. However, existing XPE materials also present some technical challenges.

[0004] First, due to the inherent characteristics of the materials, they are prone to oxidation and corrosion, resulting in a short service life and a gradual loss of waterproof and heat insulation functions after prolonged use. Second, these materials also lack mechanical properties, especially in terms of elongation at break and longitudinal and transverse tear strength, making them prone to tearing when exposed to foreign objects or under heavy pressure. Finally, there are contradictions among the various properties, resulting in insufficient long-term reliability, decreased resilience after repeated compression, and difficulty for conventional XPE to simultaneously meet the comprehensive requirements of high flame retardancy (UL94 V-0), lightweight, mechanical strength, long-term heat aging resistance, and waterproofing for applications such as new energy vehicles. Summary of the Invention

[0005] In summary, how to prepare an environmentally friendly automotive thermal insulation material with excellent mechanical strength and flame-retardant thermal insulation properties while meeting various comprehensive performance requirements has become an important research topic for those skilled in the art. Through in-depth research in this field, the applicant has finally proposed a highly flame-retardant and environmentally friendly automotive thermal insulation material and its preparation method in this application. The core advantage of the thermal insulation material obtained in this application lies in its effective balance of performance contradictions in traditional materials while maintaining excellent thermal insulation, waterproofing, corrosion resistance, and mechanical strength. It also successfully meets the requirements of high flame retardancy and environmental friendliness, greatly satisfying the environmental requirements of this type of material. Furthermore, this improvement in comprehensive performance significantly enhances the material's heat aging resistance, service life, and long-term stability, effectively avoiding the problem of thermal insulation and waterproofing functions degrading over time, which is common in traditional materials. Therefore, its comprehensive performance is particularly suitable for widespread use in public transportation vehicles and other public transportation vehicles.

[0006] A highly flame-retardant and environmentally friendly automotive thermal insulation material, the raw materials of which include at least: low-density polyethylene, polyolefin elastomer, foaming agent, flame retardant agent and solvent.

[0007] In a preferred embodiment, the mass ratio of the low-density polyethylene, polyolefin elastomer, foaming agent and flame retardant is (60~90):(10~30):(6~20):(20~40).

[0008] In a more preferred embodiment, the mass ratio of the low-density polyethylene, polyolefin elastomer, foaming agent and flame retardant is (70~80):(20~25):(8~15):(28~35).

[0009] In a preferred embodiment, the low-density polyethylene has a melt index of 2~2.5 g / 10 min and a melt index of 190℃ / 2.16 kg.

[0010] In a preferred embodiment, the polyolefin elastomer has a melt index of 3~3.5 g / 10 min and a melt index of 190℃ / 2.16 kg.

[0011] In a preferred embodiment, the foaming system agent includes a foaming agent and a crosslinking agent.

[0012] In a preferred embodiment, the mass ratio of the foaming agent to the crosslinking agent is (5~7):1.

[0013] In a preferred embodiment, the foaming agent is at least one of azodicarbonamide, p-toluenesulfonyl hydrazine, and azobisisobutyronitrile.

[0014] In a more preferred embodiment, the foaming agent is azodicarbonamide.

[0015] In a preferred embodiment, the crosslinking agent is at least one of dicumyl peroxide, benzoyl peroxide, DBPH, and BIPB.

[0016] In a more preferred embodiment, the crosslinking agent is BIPB.

[0017] In a preferred embodiment, the flame retardant system is a composition of bromine-antimony flame retardant, magnesium hydroxide, melamine cyanurate, and red phosphorus.

[0018] In a preferred embodiment, the mass ratio of the bromoantimony flame retardant, magnesium hydroxide, melamine cyanurate and red phosphorus is (12~18):(8~14):(6~10):(2~4).

[0019] In a more preferred embodiment, the mass ratio of the bromoantimony flame retardant, magnesium hydroxide, melamine cyanurate and red phosphorus is (14~15):(9~10):(7~8):(2.5~3).

[0020] In a preferred embodiment, the mass ratio of decabromodiphenyl ethane to antimony trioxide in the bromo-antimony flame retardant is (2~3):1.

[0021] In a preferred embodiment, the solvent is propanol or acetone.

[0022] In a preferred embodiment, the raw materials of the high flame-retardant and environmentally friendly automotive heat insulation material further include: functional system agents, lubricants, foaming activators, colorants, antioxidants, and auxiliary resins.

[0023] In a preferred embodiment, the mass ratio of the low-density polyethylene, the functional system agent, and the auxiliary resin is (60~90):(10~20):(15~25).

[0024] In a preferred embodiment, the mass ratio of the low-density polyethylene, the functional system agent, and the auxiliary resin is (70~80):(15~18):(20~23).

[0025] In a preferred embodiment, the functional system agent is a composition of polyphenylene sulfide and boron nitride.

[0026] In a preferred embodiment, the mass ratio of polyphenylene sulfide to boron nitride is (7~10):(3~5).

[0027] In a more preferred embodiment, the mass ratio of polyphenylene sulfide to boron nitride is (9~10):(4~5).

[0028] In a preferred embodiment, the lubricant is at least one selected from oleamide, zinc stearate, ethyl silicone oil, and erucamide.

[0029] In a more preferred embodiment, the lubricant is zinc stearate.

[0030] In a preferred embodiment, the foaming activator is at least one selected from zinc oxide, potassium hydrogen tartrate, aluminum oxide, and ammonium polyphosphate.

[0031] In a more preferred embodiment, the foaming activator is zinc oxide with an average particle size of 50-100 nm.

[0032] In a preferred embodiment, the colorant is carbon black or titanium dioxide.

[0033] In a more preferred embodiment, the colorant is carbon black.

[0034] In a preferred embodiment, the antioxidant is at least one of antioxidant 626, antioxidant 1035, antioxidant 3114, and antioxidant DSTDP.

[0035] In a more preferred embodiment, the antioxidant is antioxidant 626.

[0036] In a preferred embodiment, the preparation method of the auxiliary resin includes the following steps: S1: Vacuum drying of high-density polyethylene, followed by mixing of high-density polyethylene, glycidyl methacrylate, tetrafluoropropylene acrylate, and maleimide in a high-speed mixer after drying; S2: Adding the mixture to a twin-screw extruder for reaction and extrusion, with a screw speed of 120~150 rpm; S3: After extrusion, vacuum devolatilizing at -0.09~-0.08 MPa, followed by water cooling and pelletizing of the extruded material, and drying to obtain the final product.

[0037] A more preferred embodiment, the preparation method of the auxiliary resin specifically includes the following steps: S1: High-density polyethylene is vacuum dried at 75~80℃ for 4~5h. After drying, high-density polyethylene, glycidyl methacrylate, tetrafluoropropyl acrylate, maleimide and di-tert-butyl peroxide are added to a high-speed mixer and mixed at 120~125℃ and 500~700rpm for 5~6min; S2: The mixture is added to a twin-screw extruder with a feeding section at 150~160℃, a reaction section at 190~195℃, a homogenization section at 175~180℃, and a die section at 165~170℃ for reaction and extrusion. The screw speed is 120~150rpm; S3: After extrusion, the mixture is vacuum devolatilized at -0.09~-0.08 MPa, and the extruded strip is water-cooled and pelletized, then dried at 80~85℃ for 4~5h to obtain the final product.

[0038] In a preferred embodiment, the mass ratio of the high-density polyethylene, glycidyl methacrylate, tetrafluoropropylene acrylate, and maleimide is (12~18):(2~4):(3.5~6):(0.8~1.6).

[0039] In a more preferred embodiment, the mass ratio of the high-density polyethylene, glycidyl methacrylate, tetrafluoropropylene acrylate and maleimide is (14~15):(2~2.5):(4~5):(1~1.2).

[0040] In a more preferred embodiment, the high flame-retardant and environmentally friendly automotive heat insulation material, by weight, comprises: 60-90 parts of low-density polyethylene, 10-30 parts of polyolefin elastomer, 6-20 parts of foaming agent, 20-40 parts of flame retardant agent, 5-15 parts of solvent, 10-20 parts of functional agent, 1-2 parts of lubricant, 2-2.5 parts of foaming activator, 3-6 parts of colorant, 0.8-1.4 parts of antioxidant, and 15-25 parts of auxiliary resin.

[0041] The preparation method of the above-mentioned high flame-retardant and environmentally friendly automotive heat insulation material in this application includes the following steps: S1: After drying the required raw materials, low-density polyethylene, polyolefin elastomer, functional system agent and auxiliary resin are mixed in a mixer; S2: Flame retardant system agent, lubricant, foaming activator, colorant and antioxidant are added, and mixing continues; S3: Finally, the foaming system agent is mixed with solvent to obtain a compound; S4: The compound is fed into a single screw extruder to extrude the corresponding master sheet, the master sheet is fed into a foaming furnace for foaming, and after cooling and shaping, it is cut into finished products with a foaming ratio of 15~45.

[0042] A more preferred embodiment of the above-mentioned method for preparing high flame-retardant and environmentally friendly automotive heat insulation material specifically includes the following steps: S1: After drying the required raw materials, low-density polyethylene, polyolefin elastomer, functional system agent, and auxiliary resin are mixed in a mixer at 150-160°C and 120-180 rpm for 12-15 minutes; S2: Flame retardant system agent, lubricant, foaming activator, colorant, and antioxidant are added, and mixing continues at 120-125°C and 300-400 rpm for 8-10 minutes; S3: Finally, the... The foaming agent and solvent are mixed evenly and kneaded at 90~100℃ and 50~70rpm for 4~5min to obtain a compound; S4: The compound is placed in a double cone feeder and fed into a single screw extruder. The extrusion temperature is 120~130℃ and the die temperature is 130~135℃ to obtain the corresponding master sheet. The master sheet is fed into a foaming furnace and preheated at 150~170℃ for 5~6min. The foaming temperature is 200~230℃ for 3~4min for foaming. After completion, it is cooled and shaped, and then cut into finished products with a foaming ratio of 15~45.

[0043] The application has practical and beneficial effects: 1. The thermal insulation material finally obtained in this application can be used as an automotive interior component, which can create a high-end interior space, improve the sound insulation, heat insulation, waterproof performance and comfort of the car, effectively reduce the sound insulation and heat insulation costs of the car, and has excellent performance and service life.

[0044] 2. The core advantage of the thermal insulation material finally obtained in this application lies in its ability to effectively balance the performance contradictions of traditional materials while maintaining excellent thermal insulation, waterproofing, corrosion resistance, and mechanical strength. It also successfully addresses the requirements for high flame retardancy and environmental friendliness, greatly satisfying the environmental requirements of this type of material. Furthermore, this comprehensive performance improvement significantly enhances the material's heat aging resistance, service life, and long-term stability, effectively avoiding the problem of thermal insulation and waterproofing functions deteriorating over time, which is common in traditional materials. Therefore, its comprehensive performance makes it particularly suitable for widespread use in public transportation vehicles and other public transportation vehicles.

[0045] 3. The thermal insulation material finally obtained in this application maintains excellent flame retardant and thermal insulation performance, while reducing its elasticity decay after repeated compression, and has the characteristics of being lighter. Moreover, it is not easy to gradually lose its waterproof and thermal insulation functions after long-term use, and it is less likely to tear when exposed to foreign objects or heavy pressure. Attached Figure Description

[0046] Figure 1 This is a photograph of the high flame-retardant and environmentally friendly automotive heat insulation material prepared according to Example 1 of this application.

[0047] Figure 2 This is a schematic diagram illustrating the application of the high flame-retardant and environmentally friendly automotive thermal insulation material prepared in Example 1 of this application in automotive assembly.

[0048] Figure 3 and Figure 4 This is a TVOC test report diagram of the high flame-retardant and environmentally friendly automotive heat insulation material prepared in Example 1 of this application.

[0049] Figure 5 Figure 6 This is a diagram from the odor test report of the high flame-retardant and environmentally friendly automotive heat insulation material prepared in Example 1 of this application. Detailed Implementation

[0050] Example 1 The high flame-retardant and environmentally friendly automotive thermal insulation material, by weight, comprises the following raw materials: 75 parts low-density polyethylene, 22.5 parts polyolefin elastomer, 12 parts foaming agent, 34.5 parts flame retardant agent, 10 parts solvent, 17 parts functional agent, 1.2 parts lubricant, 2.4 parts foaming activator, 5.5 parts colorant, 0.9 parts antioxidant, and 22 parts auxiliary resin.

[0051] The low-density polyethylene has a melt index of 2 g / 10 min, a melt flow rate of 2.16 kg at 190℃, and is grade 2420H, sourced from Sinopec.

[0052] The polyolefin elastomer has a melt index of 3~3.5 g / 10 min and a melt flow rate of 2.16 kg at 190℃. The grade Engage 8440 is from Dow Chemical in the United States.

[0053] The foaming system consists of a foaming agent and a crosslinking agent in a mass ratio of 5:1; the foaming agent is azodicarbonamide; the crosslinking agent is BIPB; and the solvent is acetone.

[0054] The flame retardant system is a composition of bromine antimony flame retardant, magnesium hydroxide, melamine cyanurate and red phosphorus in a mass ratio of 15:10:7:2.5.

[0055] The functional system agent is a combination of polyphenylene sulfide and boron nitride in a mass ratio of 9:5; the polyphenylene sulfide is injection molding extrusion grade and comes from Yirong Plastics in Dongguan City, China.

[0056] The lubricant is zinc stearate; the foaming activator is zinc oxide with an average particle size of 60 nm; and the antioxidant is antioxidant 626.

[0057] The colorant is carbon black, an environmentally friendly grade, sourced from Shandong Kasong New Materials Co., Ltd., China.

[0058] The preparation method of the auxiliary resin, by weight, specifically includes the following steps: S1: High-density polyethylene is vacuum dried at 80℃ for 5h. After drying, 14 parts of high-density polyethylene, 2.4 parts of glycidyl methacrylate, 4.5 parts of tetrafluoropropylene acrylate, 1.1 parts of maleimide and 0.08 parts of di-tert-butyl peroxide are added to a high-speed mixer and mixed at 120℃ and 600rpm for 6min; S2: The mixture is added to a twin-screw extruder with a feeding section at 155℃, a reaction section at 190℃, a homogenization section at 180℃, and a die section at 170℃ for reaction and extrusion. The screw speed is 150rpm; S3: After extrusion, the mixture is vacuum devolatilized at -0.08 MPa, and the extruded strip is water-cooled and pelletized, then dried at 80℃ for 4h to obtain the final product.

[0059] High-density polyethylene, grade 5000S, is from Thai petrochemicals.

[0060] The preparation method of the high flame-retardant and environmentally friendly automotive heat insulation material in this embodiment includes the following steps: S1: After drying the required raw materials, low-density polyethylene, polyolefin elastomer, functional system agent and auxiliary resin are mixed in a mixer at 150°C and 150rpm for 15min; S2: Flame retardant system agent, lubricant, foaming activator, colorant and antioxidant are added, and mixing is continued at 120°C and 350rpm for 10min; S3: Finally, the foaming system agent and solvent are mixed evenly, and the mixture is mixed at 95°C and 60rpm for 5min to obtain a compound; S4: The compound is placed in a double cone feeder and fed into a single screw extruder, with an extrusion temperature of 125°C and a die temperature of 135°C to obtain a corresponding master sheet. The master sheet is fed into a foaming furnace, preheated at 160°C for 5min, and foamed at 220°C for 4min. After foaming, it is cooled and shaped, and cut into finished products with a foaming ratio of 25.

[0061] The final product of the high flame-retardant and environmentally friendly automotive thermal insulation material obtained in this embodiment is shown in the following image. Figure 1 As shown.

[0062] This embodiment presents a schematic diagram illustrating the application of the highly flame-retardant and environmentally friendly automotive thermal insulation material product in automotive assembly.

[0063] Example 2 The only difference between this embodiment and Embodiment 1 is as follows: The high flame-retardant and environmentally friendly automotive heat insulation material, by weight, consists of the following raw materials: 85 parts low-density polyethylene, 22.5 parts polyolefin elastomer, 12 parts foaming agent, 34.5 parts flame retardant agent, 10 parts solvent, 12 parts functional agent, 1.2 parts lubricant, 2.4 parts foaming activator, 5.5 parts colorant, 0.9 parts antioxidant, and 25 parts auxiliary resin.

[0064] All other implementation schemes are the same.

[0065] Example 3 The only difference between this embodiment and Embodiment 1 is as follows: The high flame-retardant and environmentally friendly automotive heat insulation material, by weight, consists of the following raw materials: 75 parts low-density polyethylene, 22.5 parts polyolefin elastomer, 12 parts foaming agent, 34.5 parts flame retardant agent, 10 parts solvent, 20 parts functional agent, 1.2 parts lubricant, 2.4 parts foaming activator, 5.5 parts colorant, 0.9 parts antioxidant, and 18 parts auxiliary resin.

[0066] All other implementation schemes are the same.

[0067] Comparative Example 1 The only difference between this comparative example and Example 1 is as follows: The high flame-retardant and environmentally friendly automotive thermal insulation material, by weight, consists of the following raw materials: 75 parts low-density polyethylene, 22.5 parts polyolefin elastomer, 12 parts foaming agent, 34.5 parts flame retardant agent, 10 parts solvent, 5.5 parts functional agent, 1.2 parts lubricant, 2.4 parts foaming activator, 5.5 parts colorant, 0.9 parts antioxidant, and 28 parts auxiliary resin.

[0068] All other implementation schemes are the same.

[0069] Comparative Example 2 The only difference between this comparative example and Example 1 is as follows: The high flame-retardant and environmentally friendly automotive thermal insulation material, by weight, consists of the following raw materials: 75 parts low-density polyethylene, 22.5 parts polyolefin elastomer, 12 parts foaming agent, 34.5 parts flame retardant agent, 10 parts solvent, 20 parts functional agent, 1.2 parts lubricant, 2.4 parts foaming activator, 5.5 parts colorant, 0.9 parts antioxidant, and 8.5 parts auxiliary resin.

[0070] All other implementation schemes are the same.

[0071] Comparative Example 3 The only difference between this comparative example and Example 1 is that the functional system agent is a combination of polyphenylene sulfide and boron nitride in a mass ratio of 3:5.

[0072] All other implementation schemes are the same.

[0073] Comparative Example 4 The only difference between this comparative example and Example 1 is that the flame retardant system is a composition of bromoantimony flame retardant, magnesium hydroxide, melamine cyanurate and red phosphorus in a mass ratio of 25:5:2:1.

[0074] All other implementation schemes are the same.

[0075] Comparative Example 5 The only difference between this comparative example and Example 1 is the following: the preparation method of the auxiliary resin, by mass, specifically includes the following steps: S1: High-density polyethylene is vacuum dried at 80°C for 5 hours. After drying, 25 parts of high-density polyethylene, 1.5 parts of glycidyl methacrylate, 8 parts of tetrafluoropropylene acrylate, 0.5 parts of maleimide, and 0.08 parts of di-tert-butyl peroxide are added to a high-speed mixer and mixed at 120°C and 600 rpm for 6 minutes; S2: The mixture is added to a twin-screw extruder with a feeding section at 155°C, a reaction section at 190°C, a homogenization section at 180°C, and a die section at 170°C for reaction and extrusion. The screw speed is 150 rpm; S3: After extrusion, the mixture is vacuum devolatilized at -0.08 MPa, and the extruded strip is water-cooled and pelletized, then dried at 80°C for 4 hours to obtain the final product.

[0076] All other implementation schemes are the same.

[0077] Comparative Example 6 The only difference between this comparative example and Example 1 is the following: the preparation method of the auxiliary resin, by mass, specifically includes the following steps: S1: High-density polyethylene is vacuum dried at 80°C for 5 hours. After drying, 15 parts of high-density polyethylene, 3.8 parts of glycidyl methacrylate, 1.5 parts of tetrafluoropropyl acrylate, 2.5 parts of maleimide, and 0.08 parts of di-tert-butyl peroxide are added to a high-speed mixer and mixed at 120°C and 600 rpm for 6 minutes; S2: The mixture is added to a twin-screw extruder with a feeding section at 155°C, a reaction section at 190°C, a homogenization section at 180°C, and a die section at 170°C for reaction and extrusion. The screw speed is 150 rpm; S3: After extrusion, the mixture is vacuum devolatilized at -0.08 MPa, and the extruded strip is water-cooled and pelletized, then dried at 80°C for 4 hours to obtain the final product.

[0078] All other implementation schemes are the same.

[0079] Performance testing 1. The elongation at break test shall be performed in accordance with the standard GBT6344. The elongation at break in the transverse and longitudinal directions shall be recorded. The average value of 10 tests shall be recorded in Table 1.

[0080] 2. The tear strength test shall be performed in accordance with the standard GBT10808. The transverse and longitudinal tear strength shall be recorded, and the average value of 10 tests shall be recorded in Table 1.

[0081] 3. The thermal conductivity test shall be performed in accordance with the standard GBT3399, and the average value of 10 tests shall be recorded in Table 1.

[0082] 4. Waterproofing - water absorption rate test reference standard GBT8810, and the result is the average of 10 tests recorded in Table 1.

[0083] 5. Corrosion resistance test: Prepare 50 mm × 25 mm × 5 mm material samples, vacuum dry at 60℃ for 24 h, and then cool to room temperature (23~26℃). Then, completely immerse the test samples in 10 wt% sodium hydroxide solution for 720 h and 50 wt% ethylene glycol solution for 360 h. After immersion, observe whether the surface of the sample is still smooth and undamaged (10 wt% sodium hydroxide solution) and whether there is edge warping (50 wt% ethylene glycol solution). The results are recorded in Table 1.

[0084] 6. The TVOC test in Example 1 is as follows: Figure 3 and Figure 4 As shown.

[0085] 7. Odor test of Example 1 as follows Figure 5 and Figure 6 As shown.

[0086] Table 1 Performance Test Results

[0087] Based on the final performance test results of the examples and comparative examples, comparative examples 1 and 2 did not use the correct ratio of functional system agents and auxiliary resin raw materials, resulting in lower performance than the examples in the corresponding tests.

[0088] Comparative Examples 3 to 6, on the other hand, did not use the raw material ratio scheme specified in this application and did not prepare the auxiliary resin according to the specified method, which resulted in a significant decrease in their effect in the system and ultimately a significant decrease in their overall performance.

Claims

1. A highly flame-retardant and environmentally friendly automotive thermal insulation material, characterized in that: Its raw materials include at least: low-density polyethylene, polyolefin elastomer, foaming agent, flame retardant agent and solvent; The mass ratio of the low-density polyethylene, polyolefin elastomer, foaming agent and flame retardant is (60~90):(10~30):(6~20):(20~40). The low-density polyethylene has a melt index of 2~2.5 g / 10 min and a melt index of 2.16 kg at 190 °C. The polyolefin elastomer has a melt index of 3~3.5 g / 10 min and a melt index of 2.16 kg at 190 °C. The foaming system agent includes a foaming agent and a crosslinking agent, with a mass ratio of (5~7):

1.

2. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 1, characterized in that: The foaming agent is at least one of azodicarbonamide, p-toluenesulfonyl hydrazine, and azobisisobutyronitrile; the crosslinking agent is at least one of dicumyl peroxide, benzoyl peroxide, DBPH, and BIPB.

3. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 2, characterized in that: The flame retardant system is a composition of bromine antimony flame retardant, magnesium hydroxide, melamine cyanurate and red phosphorus, in a mass ratio of (12~18):(8~14):(6~10):(2~4).

4. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 3, characterized in that: The mass ratio of decabromodiphenyl ethane to antimony trioxide in the bromo-antimony flame retardant is (2~3):

1.

5. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 1, characterized in that: The raw materials of the high flame-retardant and environmentally friendly automotive heat insulation material also include: functional system agents, lubricants, foaming activators, colorants, antioxidants, and auxiliary resins.

6. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 5, characterized in that: The low-density polyethylene has a mass ratio of functional system agent to auxiliary resin of (60~90):(10~20):(15~25).

7. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 6, characterized in that: The functional system agent is a composition of polyphenylene sulfide and boron nitride in a mass ratio of (7~10):(3~5).

8. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 7, characterized in that: The preparation method of the auxiliary resin includes the following steps: S1: Vacuum-dried high-density polyethylene, glycidyl methacrylate, tetrafluoropropylene acrylate and maleimide are added to a high-speed mixer for mixing; S2: The product obtained in S1 is added to a twin-screw extruder for reaction and extrusion; S3: After extrusion, vacuum devolatilization is performed, the extruded strip is water-cooled and pelletized, and then dried to obtain the final product. The mass ratio of the high-density polyethylene, glycidyl methacrylate, tetrafluoropropylene acrylate and maleimide is (12~18):(2~4):(3.5~6):(0.8~1.6).

9. The high flame-retardant and environmentally friendly automotive heat insulation material according to claim 8, characterized in that: The high flame-retardant and environmentally friendly automotive heat insulation material, by weight, comprises the following raw materials: 60-90 parts low-density polyethylene, 10-30 parts polyolefin elastomer, 6-20 parts foaming agent, 20-40 parts flame retardant agent, 5-15 parts solvent, 10-20 parts functional agent, 1-2 parts lubricant, 2-2.5 parts foaming activator, 3-6 parts colorant, 0.8-1.4 parts antioxidant, and 15-25 parts auxiliary resin.

10. A method for preparing a high flame-retardant and environmentally friendly automotive heat insulation material according to any one of claims 1 to 9, characterized in that: Specifically, the following steps are included: S1: After drying the required raw materials, mix low-density polyethylene, polyolefin elastomer, functional system agent and auxiliary resin in a mixer; S2: Add flame retardant system agent, lubricant, foaming activator, colorant and antioxidant, and continue mixing; S3: Finally, mix the foaming system agent with solvent to obtain a compound; S4: Feed the compound into a single screw extruder to extrude the corresponding master sheet, feed the master sheet into a foaming furnace for foaming, and after cooling and shaping, cut into finished products with a foaming ratio of 15~45.

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