Environment-friendly halogen-free TPU (Thermoplastic Polyurethane) material capable of resisting 136 DEG C and preparation method thereof

Abstract

The invention relates to the technical field of TPU processing, in particular to an environment-friendly halogen-free 136 DEG C-resistant TPU material and a preparation method thereof, and the environment-friendly halogen-free 136 DEG C-resistant TPU material is prepared from the following raw materials in parts by weight: 70-80 parts of TPU, 3-5 parts of an anti-aging agent, 10-15 parts of silicon dioxide, 15-20 parts of a halogen-free flame retardant, 1-2 parts of a grafting lubricant, 0.5-1 part of a dispersing agent and 0.5-1 part of a compatilizer. According to the TPU material prepared by adopting the formula, the long-term heat-resistant temperature can reach 136 DEG C, the peak value heat shock resistance is 180 DEG C * 30 minutes, softening collapse is avoided, the working condition requirements of continuous 125 DEG C and the peak value of 180 DEG C in an oven / baking oven are directly met, and the TPU material has the advantages of being simple in preparation process, low in cost and high in practicability. Meanwhile, the advantages of softness, wear resistance and food grade of TPU are reserved.

Description

Technical Field

[0001] This application relates to the field of TPU processing technology, and more specifically, to an environmentally friendly, halogen-free TPU material that is resistant to 136°C and its preparation method. Background Technology

[0002] TPU sheaths, with their softness, wear resistance, oil resistance, environmental friendliness, and food-grade design, have become the ideal material for sheaths in the high-temperature zones of ovens and grills, such as heating element / thermocouple wire sheaths, wear-resistant sheaths for door hinges, springs, connecting rods, and hot air circulation motor lead wire harness sheaths.

[0003] However, the upper limit of the long-term operating temperature of TPU remains a core bottleneck for its entry into the "high-temperature sheathing" niche market. Commercially available polyester or polyether TPUs generally have a long-term temperature resistance of 80-90℃, with a short-term peak of 100℃. When the ambient temperature exceeds 100℃ for an extended period, the urethane bonds in the TPU begin to undergo reversible thermal decomposition: the hard segment micro-regions melt, leading to a sharp drop in modulus, while the soft segment undergoes oxidation and chain breakage, causing surface powdering. Macroscopically, this manifests as sheath softening, collapse, and cracking, ultimately resulting in the loss of mechanical protection for internal wiring harnesses or moving parts. More seriously, trace amounts of aromatic amines or isocyanate monomers may precipitate during the decomposition process, posing food safety risks. Although the thermal decomposition temperature can be increased to some extent by adding hindered phenol / phosphite antioxidants, benzotriazole light stabilizers, or barrier fillers such as nano-montmorillonite or silicate sheets, the improvement in thermal aging performance is limited due to the inherent chemical structure of TPU, making it difficult to meet the stringent conditions of "continuous 125℃, peak 180℃, and circulating hot air impact" inside an oven.

[0004] To address these issues, the current industry practice is to add a layer of fiberglass or silicone rubber tubing over the TPU sheath for double protection. However, this not only increases the outer diameter and sacrifices flexibility but also leads to increased costs and decreased assembly efficiency. How to maintain the food-grade, soft, and wear-resistant properties of TPU while ensuring its long-term temperature resistance exceeding 100℃ or even 120℃ has become a critical technical challenge for upgrading high-end ovens and grills. Summary of the Invention

[0005] To address the issue that the improvement in the thermal aging performance of TPU is limited and it is difficult to meet the harsh operating conditions of "continuous 125℃, peak 180℃, and circulating hot air impact" inside the oven, this application provides an environmentally friendly halogen-free TPU material that can withstand 136℃ and its preparation method.

[0006] In a first aspect, this application provides an environmentally friendly, halogen-free TPU material resistant to 136℃, using the following technical solution: An environmentally friendly, halogen-free TPU material resistant to 136℃ is prepared from the following raw materials in parts by weight: 70-80 parts TPU, 3-5 parts anti-aging agent, 10-15 parts silica, 15-20 parts halogen-free flame retardant, 1-2 parts graft lubricant, 0.5-1 parts dispersant, and 0.5-1 parts compatibilizer; wherein the anti-aging agent is composed of benzimidazole and silane containing antioxidant groups in a weight ratio of 1:(2-5).

[0007] By adopting the above technical solution, the prepared TPU material can withstand a long-term heat resistance temperature of up to 136℃ and a peak heat shock resistance of 180℃×30min without softening or collapse. It meets the working conditions of "continuous 125℃ and peak 180℃" inside the oven / grill, while retaining the advantages of TPU such as softness, wear resistance and food grade.

[0008] The benzimidazole compounds and antioxidant-containing silanes used in this application are compounded in a specific ratio to greatly improve the aging resistance of TPU materials, enabling the sheath to remain unsoftened and collapsed, and to prevent surface powdering and cracking, even under continuous forced-air conditions at 125°C. Simultaneously, both the benzimidazole compounds and the antioxidant-containing silanes are food-contact grade raw materials, and their proportion in the total formulation is ≤5wt%, ensuring that no aromatic amines or isocyanate monomers are released during the material's pyrolysis process at 136°C.

[0009] Grafted lubricants and compatibilizers work together to improve the dispersibility of high silica and halogen-free flame retardants, avoid the decline in mechanical properties caused by filler agglomeration, and ensure that the sheath maintains its flexibility during long-term bending.

[0010] Silica forms a physical barrier layer in the TPU system, reducing oxygen permeation and heat conduction. It works synergistically with halogen-free flame retardants to further inhibit thermal decomposition, enabling the material to pass UL 94V-0 with a thickness of 1mm. At the same time, the smoke density Ds(4min) < 200 meets the environmental protection requirements of IEC 60707 / EN 45545-2HL3, avoiding the increase in outer diameter, decrease in flexibility, and reduction in assembly efficiency caused by traditional TPU + glass fiber / silicone rubber double-layer sleeve.

[0011] This application achieves UL94V-0 flame retardancy through a halogen-free flame retardant system, and the silane component in the anti-aging agent can capture the isocyanate monomers generated by cracking, so that the migration amount is lower than the EU 10 / 2011 regulatory limit (≤10ppb), eliminating the safety hazards of oven food contact.

[0012] Preferably, the silane containing antioxidant groups includes at least one of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl-trimethoxysilane, 3-(methacryloyloxy)propyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl-dimethoxysilane, and aromatic amine-silane (diphenylaminosilane).

[0013] By adopting the above technical solution and optimizing the types of silanes containing antioxidant groups, and using them in combination with benzimidazoles, the high-temperature resistance of TPU materials is further improved, enabling the sheath to operate continuously at 136°C for thousands of hours without softening or cracking, thus extending its service life. Simultaneously, it ensures that the anti-aging agent does not volatilize or migrate under high-temperature conditions, providing long-lasting protection. Furthermore, its silicon-oxygen bonds form a dense, glassy film on the sheath surface, blocking oxygen and oil, and preventing the release of small molecules from decomposition, maintaining food-grade safety. Preferably, the halogen-free flame retardant is prepared by the following method: The cage-type polysilsesquioxane, solid flame retardant and solvent are mixed, heated to 80-90℃, and then phosphate ester coupling agent is added. The mixture is stirred for 60-80 minutes, and the solvent is recovered by vacuum distillation to obtain halogen-free flame retardant. The weight ratio of the cage-type polysilsesquioxane, the phosphate coupling agent, and the solid flame retardant is (2-4):(0.8-1.2):15; The solid flame retardant is composed of melamine polyphosphate, melamine cyanurate and inorganic hydroxide in a weight ratio of (2-3):1:(4-6).

[0014] By adopting the above technical solution, a material with good flame retardant effect is obtained, which enables the TPU material to pass UL94V-0 in one go with a thickness of 1.6mm. At the same time, the smoke density release is reduced by more than 50%, while ensuring that the sheath remains soft, resistant to high temperature of 136℃, and will not become brittle or precipitate white frost.

[0015] Among these, hydroxides and melamine salts are highly hydrophilic and will slowly accumulate on the product surface when heated or stressed, resulting in what appears to be "blooming" or "powdering." Furthermore, their addition amounts are relatively large, affecting the softness and mechanical strength of TPU. Cage-type polysilsesquioxanes, on the other hand, contain a large number of Si-O-Si structures on their surface that can combine with melamine polyphosphate, melamine cyanurate, and hydroxides, and then with phosphate coupling agents. This significantly improves the bonding force between hydroxides and melamine salts and the TPU material, reducing migration and precipitation. Simultaneously, it greatly enhances the flame-retardant properties of halogen-free flame retardants, requiring less addition and not affecting the softness and mechanical strength of TPU.

[0016] Preferably, the cage-like polysilsesquioxane is at least one of octaacryloxypropyl-cage-like polysilsesquioxane, octaisobutyl-cage-like polysilsesquioxane, octamethacryloxypropyl-cage-like polysilsesquioxane, octahydroxybutyl-cage-like polysilsesquioxane, and dodecylphenyl-cage-like polysilsesquioxane.

[0017] By adopting the above technical solutions, the types of cage-type polysilsesquioxanes are optimized, and the bonding force between cage-type polysilsesquioxanes and melamine polyphosphate, melamine cyanurate, and hydroxides is improved, ensuring that even after long-term baking at 136℃, no "frost" or powdering is observed in the protective sleeve. At the same time, the flame retardant efficiency is doubled, the amount of flame retardant used is reduced, and the softness and mechanical strength are guaranteed.

[0018] Preferably, the grafting lubricant is polyphthalamide.

[0019] By adopting the above technical solution, the highly polar phthalamide groups of poly(phthalamide) can hydrogen bond with the hard segments of TPU to form a heat-resistant micronetwork, allowing the sheath to maintain its original shape even under a peak impact of 180°C. Simultaneously, it can continuously migrate and form a film under continuous operating conditions at 136°C, reducing the coefficient of friction on the inner surface of the sheath and preventing insulation wear during thermal expansion and contraction of the wiring harness. Furthermore, PPA itself is halogen-free, food-grade, and does not leach or migrate to food contact surfaces, maintaining environmental protection and safety compliance.

[0020] Preferably, the TPU is composed of polyester TPU and polyether TPU in a weight ratio of (4-6):1.

[0021] By adopting the above technical solutions, optimizing the amount and type of TPU, the heat resistance and aging resistance of TPU materials can be further improved, while the flexibility and mechanical properties of TPU materials can be further enhanced.

[0022] Preferably, the dispersant comprises at least one of polyethylene wax, polyvinyl alcohol, calcium stearate, zinc stearate, barium stearate, and oxidized polyethylene wax.

[0023] By adopting the above technical solutions and optimizing the types of dispersants, the dispersion of anti-aging agents, silica, and halogen-free flame retardants can be promoted, enabling them to be uniformly dispersed in the TP matrix. This improves the high temperature resistance, flame retardancy, and mechanical properties of the TPU material, ensuring that the protective sleeve will not become brittle or precipitate white frost when used at a high temperature of 136℃.

[0024] Preferably, the compatibilizer includes at least one of ethylene-methyl acrylate-maleic anhydride copolymer, ethylene-methyl acrylate copolymer grafted with glycidyl methacrylate, POE grafted with maleic anhydride copolymer, and SEBS grafted with maleic anhydride copolymer. By adopting the above technical solution, the type of compatibilizer is optimized, promoting the compatibility of TPU with silica anti-aging agents and halogen-free flame retardants. This gives the TPU material good high-temperature resistance, allowing it to be used for a long time at 136°C without powdering or cracking. At the same time, it gives the TPU material good tensile strength and elongation at break, ensuring that the sheath still has sufficient resilience and support at high temperatures, preventing collapse.

[0025] Secondly, this application provides a method for preparing an environmentally friendly, halogen-free TPU material resistant to 136℃, using the following technical solution: A method for preparing an environmentally friendly, halogen-free TPU material resistant to 136℃ includes the following preparation steps: S1. Mix TPU, anti-aging agent, silica, halogen-free flame retardant, graft lubricant, dispersant and compatibilizer to obtain a mixture; S2. The mixture is then put into a twin-screw extruder for extrusion granulation to obtain an environmentally friendly, halogen-free TPU material that can withstand 136℃.

[0026] Preferably, the twin-screw extruder has a screw speed of 180-240 rpm and an extrusion temperature of 200-220℃.

[0027] By adopting the above technical solution, this two-step process maximizes the synergistic effect of the formulation with a simple "first homogenization - then extrusion" flow: S1 high-mixing enables the benzimidazole / silane anti-aging agent, silica, and halogen-free flame retardant to achieve molecular-level pre-dispersion with TPU under the action of a compatibilizer, reducing interfacial tension by 50% and laying the foundation for the subsequent heat-resistant network; S2 features a precisely designed twin-screw shear-temperature control zone, completing the in-situ reaction between the acid anhydride and TPU end groups, and between the silane and SiO2 surface at 200-220℃, forming a heat-resistant siloxane cross-linked layer and a dense expanded carbon layer, resulting in a tensile retention rate of ≥85% at 136℃ / 1000h and UL-94V-0 reaching 1mm. Simultaneously, the grafted lubricant reduces melt viscosity by 15%, preventing high-temperature degradation, and food-grade migration is <5ppm; single extrusion molding can be achieved without secondary coating, reducing costs. With a wide process window and high yield, continuous production can directly produce soft, wear-resistant, food-grade oven sleeve material that can withstand 136℃ for a long time, solving the industry problems of traditional TPU softening at high temperatures, toxicity release, and bulky double-layer structure.

[0028] In summary, this application has the following beneficial effects: 1. Through the synergistic effect of specific components, the long-term continuous service temperature of TPU material is increased from 80-90℃ in the existing technology to 136℃ (i.e., the long-term temperature resistance is improved by about 50-70%), while it can withstand the instantaneous high temperature impact of 180℃. This performance directly solves the problems of softening, collapse, and cracking caused by the cleavage of urethane bonds in existing TPU sheaths in environments above 100℃ for a long time, filling the material gap for food-grade flexible sheaths in the high-temperature zone inside ovens / furnaces (continuous 125℃, peak 180℃). Detailed Implementation

[0029] Preparation Example The phosphate coupling agent is manufactured by Jingde Chemical, and its model number is PM1000.

[0030] Preparation Example 1 A halogen-free flame retardant is prepared by the following method: Mix 20g of cage-type polysilsesquioxane (octaacryloyloxypropyl-cage-type polysilsesquioxane), 150g of solid flame retardant and 400g of solvent (ethyl acetate), heat to 80℃, add 8g of phosphate coupling agent, stir for 60min, distill under reduced pressure, and recover the solvent to obtain halogen-free flame retardant. The weight ratio of cage-type polysilsesquioxane, phosphate coupling agent and solid flame retardant is 2:0.8:15; The solid flame retardant is composed of melamine polyphosphate, melamine cyanurate and inorganic hydroxide (aluminum hydroxide) in a weight ratio of 2:1:4.

[0031] Preparation Example 2 A halogen-free flame retardant is prepared by the following method: Mix 30g of cage-type polysilsesquioxane (octaisobutyl-cage-type polysilsesquioxane), 150g of solid flame retardant and solvent 400 (isopropanol), heat to 85℃, add 10g of phosphate coupling agent, stir for 70min, distill under reduced pressure, recover the solvent, and obtain halogen-free flame retardant. The weight ratio of cage-type polysilsesquioxane, phosphate coupling agent and solid flame retardant is 3:1:15; The solid flame retardant is composed of melamine polyphosphate, melamine cyanurate and inorganic hydroxide (magnesium hydroxide) in a weight ratio of 2.5:1.3:5.

[0032] Preparation Example 3 A halogen-free flame retardant is prepared by the following method: Mix 40g of cage-type polysilsesquioxane (octamethacryloxypropyl-cage-type polysilsesquioxane), 150g of solid flame retardant and 400g of solvent (toluene), heat to 90℃, add 12g of phosphate coupling agent, stir for 80min, distill under reduced pressure, and recover the solvent to obtain halogen-free flame retardant. The weight ratio of cage-type polysilsesquioxane, phosphate coupling agent and solid flame retardant is 4:1.2:15; The solid flame retardant is composed of melamine polyphosphate, melamine cyanurate and inorganic hydroxide (aluminum hydroxide) in a weight ratio of 2:1.5:6. Example

[0033] Polyester-type TPU is from BASF. C 85 A 50. The polyether-type TPU is from Covestro. 945U.

[0034] Ethylene-methyl acrylate-maleic anhydride copolymer is Arkema's 4210.

[0035] Ethylene methyl acrylate copolymer grafted with glycidyl methacrylate is Arkema's AX8840.

[0036] POE-grafted maleic anhydride copolymer is from Dow Chemical. N525.

[0037] Poly(phthalamide) is Solvay A-1133HS.

[0038] Example 1 An environmentally friendly, halogen-free TPU material resistant to 136℃ is prepared by the following method: S1. Mix 700g of TPU, 30g of anti-aging agent, 100g of silica, 150g of halogen-free flame retardant (from Preparation Example 1), 10g of graft lubricant (polyphthalamide), 5g of dispersant (polyethylene wax) and 5g of compatibilizer (ethylene-methyl acrylate-maleic anhydride copolymer) to obtain a mixture. The anti-aging agent is composed of benzimidazole (2-mercaptobenzimidazole) and silane containing antioxidant groups (3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl-trimethoxysilane) in a weight ratio of 1:2; TPU is composed of polyester TPU and polyether TPU in a weight ratio of 4:1; The average particle size of silica is 100 nm; S2. The mixture is then fed into a twin-screw extruder for extrusion granulation to obtain an environmentally friendly, halogen-free TPU material that is resistant to 136℃. The screw speed of the twin-screw extruder is 180 rpm, and the extrusion temperature is 200℃.

[0039] The difference between Examples 2-3 and Example 1 lies in the types, amounts, and parameters of raw materials used to prepare the environmentally friendly, halogen-free, 136℃-resistant TPU material. Specific differences are shown in Table 1. Table 1. Raw material types, dosages, and parameters for preparing environmentally friendly halogen-free TPU material resistant to 136℃. Example 4 An environmentally friendly, halogen-free TPU material resistant to 136℃. The difference between this embodiment and Embodiment 1 is that the halogen-free flame retardant is composed of melamine polyphosphate, melamine cyanurate and inorganic hydroxide (aluminum hydroxide) in a weight ratio of 2:1:4.

[0040] Example 5 An environmentally friendly, halogen-free TPU material resistant to 136℃ is described in this embodiment, which differs from Embodiment 1 in that the TPU is a polyester-type TPU.

[0041] Example 6 An environmentally friendly, halogen-free TPU material resistant to 136°C. The difference between this embodiment and Example 1 is that the cage-like polysilsesquioxane in Example 1 is replaced with a solvent (ethyl acetate).

[0042] Example 7 An environmentally friendly, halogen-free TPU material resistant to 136℃. The difference between this embodiment and Example 1 is that the solid flame retardant in Example 1 is composed of melamine polyphosphate and inorganic hydroxide (aluminum hydroxide) in a weight ratio of 2:4.

[0043] Comparative Example Comparative Example 1 An environmentally friendly halogen-free TPU material. The difference between this comparative example and Example 1 is that the anti-aging agent is a benzimidazole derivative. Comparative Example 2 An environmentally friendly halogen-free TPU material, the difference between this comparative example and Example 1 is that the anti-aging agent is composed of benzimidazole and silane containing antioxidant groups in a weight ratio of 1:2.

[0044] Comparative Example 3 An environmentally friendly halogen-free TPU material, the difference between this comparative example and Example 1 is that the grafting lubricant is replaced with N,N'-ethylene bis-stearamide.

[0045] Detection methods / test methods The environmentally friendly halogen-free TPU materials with a temperature resistance of 136℃ obtained in Examples 1-7 and the environmentally friendly halogen-free TPU materials in Comparative Examples 1-3 were extruded and calendered into sheets with a thickness of 1.0 mm and stable quality through a single-screw extrusion calendering line. The following tests were then conducted: Tensile strength and elongation at break: as per ASTM D412; Thermal aging test: 136℃×1000h according to ASTM D573; Thermal shock test: 180℃×30min according to IEC60811-508. Flame retardant performance: UL 94 vertical burning test; Smoke density: ISO 5659-2 test; Experimental data are shown in Table 2. Table 2. Experimental data of Examples 1-7 and Comparative Examples 1-3 This application successfully improves the long-term temperature resistance of TPU from 80-90℃ to 136℃ through a specific aging-resistant, flame-retardant, and lubricating synergistic system, while maintaining food-grade safety, V-0 flame retardancy, and high flexibility, providing a halogen-free and environmentally friendly technical solution for high-temperature sheathing inside ovens / grills.

[0046] The tensile strength retention rate at 136℃×1000h in Examples 1-3 is ≥90%, and the elongation at break retention rate at 180℃×30min is also ≥90%, proving that the "benzimidazole + silane containing antioxidant groups" compound system is synergistically stable with the phosphorus-nitrogen halogen-free flame retardant system and can withstand the 136℃ working condition for a long time.

[0047] In Comparative Example 3, the flame retardant rating was maintained, but the mechanical properties decreased significantly, demonstrating the irreplaceable role of grafted lubricants in high-temperature lubrication and system stability.

[0048] Examples 1-4 and 7 maintained UL 94V-0 after thermal aging, indicating that the phosphorus-nitrogen-silicon synergistic carbon layer in the formulation has a complete structure and no degradation in flame retardant performance under long-term high temperature.

[0049] Examples 5-6 show a decrease from the original V-0 to V-1, indicating that when the polyester / polyether ratio is too high or cage-type polysilsesquioxane is missing, the thermal stability is insufficient and the density of the carbon layer decreases.

[0050] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An environmentally friendly, halogen-free TPU material resistant to 136℃, characterized in that, It is prepared from the following parts by weight of raw materials: 70-80 parts TPU The aging resistant agent consists of 3-5 parts of aging resistant agent, 10-15 parts of silica, 15-20 parts of halogen-free flame retardant, 1-2 parts of graft lubricant, 0.5-1 part of dispersant, and 0.5-1 part of compatibilizer; the aging resistant agent is composed of benzimidazole and silane containing antioxidant groups in a weight ratio of 1:(2-5).

2. The environmentally friendly, halogen-free TPU material resistant to 136℃ as described in claim 1, characterized in that: The silane containing antioxidant groups includes at least one of 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl-trimethoxysilane, 3-(methacryloyloxy)propyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propyl-dimethoxysilane, and aromatic amine-silane (diphenylaminosilane).

3. The environmentally friendly, halogen-free, 136℃-resistant TPU material according to claim 2, characterized in that, The halogen-free flame retardant is prepared by the following method: a cage-type polysilsesquioxane, a solid flame retardant and a solvent are mixed, heated to 80-90°C, a phosphate coupling agent is added, the mixture is stirred for 60-80 minutes, and the solvent is recovered by vacuum distillation to obtain the halogen-free flame retardant. The weight ratio of the cage-type polysilsesquioxane, the phosphate coupling agent, and the solid flame retardant is (2-4):(0.8-1.2):15; The solid flame retardant is composed of melamine polyphosphate, melamine cyanurate and inorganic hydroxide in a weight ratio of (2-3):1:(4-6).

4. The environmentally friendly, halogen-free TPU material resistant to 136℃ as described in claim 1, characterized in that: The cage-like polysilsesquioxane is at least one of octaacryloxypropyl-cage-like polysilsesquioxane, octaisobutyl-cage-like polysilsesquioxane, octamethacryloxypropyl-cage-like polysilsesquioxane, octahydroxybutyl-cage-like polysilsesquioxane, and dodecylphenyl-cage-like polysilsesquioxane.

5. The environmentally friendly, halogen-free TPU material resistant to 136℃ as described in claim 1, characterized in that: The grafting lubricant is polyphthalamide.

6. The environmentally friendly, halogen-free TPU material resistant to 136℃ according to claim 1, characterized in that: The TPU is composed of polyester TPU and polyether TPU in a weight ratio of (4-6):

1.

7. The environmentally friendly, halogen-free TPU material resistant to 136℃ according to claim 1, characterized in that: The dispersant includes at least one of polyethylene wax, polyvinyl alcohol, calcium stearate, zinc stearate, barium stearate, and oxidized polyethylene wax.

8. The environmentally friendly, halogen-free TPU material resistant to 136℃ according to claim 1, characterized in that: The compatibilizer includes at least one of ethylene-methyl acrylate-maleic anhydride copolymer, ethylene-methyl acrylate copolymer grafted with glycidyl methacrylate, POE-grafted with maleic anhydride copolymer, and SEBS-grafted with maleic anhydride copolymer.

9. A method for preparing an environmentally friendly, halogen-free, 136℃-resistant TPU material as described in any one of claims 1-8, characterized in that, The preparation steps include the following: S1. Mix TPU, anti-aging agent, silica, halogen-free flame retardant, graft lubricant, dispersant and compatibilizer to obtain a mixture; S2. The mixture is then put into a twin-screw extruder for extrusion granulation to obtain an environmentally friendly, halogen-free TPU material that can withstand 136℃.

10. The method for preparing an environmentally friendly, halogen-free TPU material resistant to 136℃ according to claim 9, characterized in that: The twin-screw extruder has a screw speed of 180-240 rpm and an extrusion temperature of 200-220℃.

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