A heat-resistant, flame-retardant, and environmentally friendly EVA composite material and its preparation method

Abstract

This invention relates to the field of EVA film technology, specifically to a heat-resistant, flame-retardant, and environmentally friendly EVA composite material and its preparation method. The heat-resistant, flame-retardant, and environmentally friendly EVA composite material is characterized by comprising the following raw materials in parts by weight: 30-40 parts ethylene-vinyl acetate copolymer, 10-20 parts low-density polyethylene, 15-25 parts halogenated flame retardant, 10-20 parts inorganic flame retardant, 5-10 parts maleic anhydride-grafted ethylene-ethyl acrylate copolymer, 2-4 parts triethylene glycol diisooctanoate, 1-2 parts octadecyl alcohol polyoxyethylene ether, 1-2 parts isotridecyl alcohol polyoxyethylene ether, and 1-3 parts antioxidant. The heat-resistant, flame-retardant, and environmentally friendly EVA composite material of this application achieves excellent heat-resistant and flame-retardant properties through specific components and proportions, while maintaining the original mechanical properties of EVA composite materials.

Description

Technical Field

[0001] This invention relates to the field of EVA film technology, and in particular to a heat-resistant, flame-retardant, and environmentally friendly EVA composite material and its preparation method. Background Technology

[0002] EVA, or ethylene-vinyl acetate copolymer, is a thermoplastic elastomer. The vinyl acetate (VA) content in EVA is typically between 15% and 70%, and its glass transition temperature is approximately 30°C. This gives it excellent flexibility, impact resistance, adhesion, and chemical resistance. Consequently, EVA is widely used in packaging materials, building decoration, shoe materials, wire and cable sheathing, photovoltaic module encapsulation, and automotive interiors. For example, in photovoltaic modules, EVA film, as an encapsulation material, effectively protects solar cells and improves module transmittance and reliability. In medical devices, due to its biocompatibility, it is also used in disposable medical devices.

[0003] However, traditional EVA materials suffer from insufficient flame retardancy, easily softening and deforming at high temperatures, affecting product lifespan and performance stability. Furthermore, they lack self-extinguishing properties and may rapidly spread fire upon contact with an ignition source, increasing the risk of fire. To improve the flame retardancy of EVA materials, researchers have conducted extensive exploration and practice, improving their performance by adding various flame retardants and modifiers. Existing technologies typically introduce inorganic nanoparticles as fillers to enhance the thermal stability and flame retardancy of EVA. However, uneven dispersion of nanoparticles can lead to increased internal structural defects in EVA materials, thus affecting the quality of the final product. Therefore, it is necessary to develop a novel heat-resistant, flame-retardant, and environmentally friendly EVA composite material. This composite material should not only significantly improve the flame retardancy of EVA while maintaining its original excellent physical and chemical properties, but also effectively solve the problem of internal defects in EVA materials caused by uneven nanoparticle dispersion. Summary of the Invention

[0004] To effectively address the internal defects in EVA materials caused by uneven nanoparticle dispersion, this application provides a heat-resistant, flame-retardant, and environmentally friendly EVA composite material and its preparation method. This heat-resistant, flame-retardant, and environmentally friendly EVA composite material achieves excellent heat resistance and flame retardancy through specific components and proportions, while maintaining the original mechanical properties of the EVA composite material.

[0005] In the first aspect, the heat-resistant, flame-retardant, and environmentally friendly EVA composite material provided in this application adopts the following technical solution: A heat-resistant, flame-retardant, and environmentally friendly EVA composite material comprises the following raw materials in parts by weight: 30-40 parts of ethylene-vinyl acetate copolymer, 10-20 parts of low-density polyethylene, 15-25 parts of halogenated flame retardant, 10-20 parts of inorganic flame retardant, 5-10 parts of maleic anhydride-grafted ethylene-ethyl acrylate copolymer, 2-4 parts of triethylene glycol diisooctanoate, 1-2 parts of octadecyl alcohol polyoxyethylene ether, 1-2 parts of isotridecyl alcohol polyoxyethylene ether, and 1-3 parts of antioxidant.

[0006] In the above technical solution, ethylene-vinyl acetate copolymer and low-density polyethylene serve as the base material of EVA composite material, providing good flexibility and processing performance. The synergistic effect of halogenated flame retardants and inorganic flame retardants effectively enhances the flame retardant performance of EVA composite material. Maleic anhydride-grafted ethylene-ethyl acrylate copolymer, as a compatibilizer, improves the compatibility between raw materials, allowing nanoparticles to be more uniformly dispersed in EVA composite material and reducing internal defects. Triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotridecyl alcohol polyoxyethylene ether are added as additives, significantly improving the flame retardancy and smoke suppression of EVA composite material through synergistic effects. First, the synergistic effect of the three enhances interfacial compatibility and dispersibility, allowing flame retardants, especially inorganic flame retardants, to be more uniformly distributed in the polymer matrix, forming a denser and more uniform layer structure. This effectively isolates oxygen and prevents flame spread during combustion. At the same time, they can rapidly form a protective film on the surface of EVA composite material, hindering heat transfer paths and promoting the development of the char layer by regulating crystallization behavior, further improving self-extinguishing and flame-retardant capabilities.

[0007] Preferably, the inorganic flame retardant is a mixture of aluminum hydroxide, magnesium hydroxide and aluminum borate whiskers, wherein the mass ratio of aluminum hydroxide, magnesium hydroxide and aluminum borate whiskers is 1:(0.8-1.2):(0.1-0.5).

[0008] In the above technical solution, this application selects aluminum hydroxide, magnesium hydroxide, and aluminum borate whiskers as inorganic flame retardants for EVA composite materials. The combined use of aluminum hydroxide, magnesium hydroxide, and aluminum borate whiskers effectively improves the flame retardant performance. Aluminum hydroxide and magnesium hydroxide decompose at high temperatures to produce water vapor, diluting combustible gases and absorbing heat, thereby lowering the combustion temperature. Aluminum borate whiskers form a robust char layer during combustion, effectively isolating oxygen and preventing further flame spread. Furthermore, the addition of aluminum borate whiskers further enhances the mechanical strength and heat resistance of the EVA composite material, enabling it to maintain excellent physical and chemical properties even at high temperatures.

[0009] Preferably, the halogenated flame retardant is one or more of decabromodiphenyl ethane, brominated epoxy resin, and melamine polyphosphate.

[0010] In the above technical solution, by selecting these halogenated flame retardants and adding them to EVA composite materials, hydrogen halide gas can be generated at high temperature, capturing free radicals generated during combustion and interrupting the combustion chain reaction, thereby achieving the purpose of flame retardancy. They can also work well with inorganic flame retardants to further enhance the flame retardant performance of composite materials.

[0011] Preferably, the halogenated flame retardant is a mixture of decabromodiphenyl ethane and brominated epoxy resin in a mass ratio of 1:(0.3-0.5).

[0012] In the above technical solution, by adjusting the halogenated flame retardant in the EVA composite material to decabromodiphenyl ethane and brominated epoxy resin, the flame retardant and processing properties of the composite material can be further optimized. Decabromodiphenyl ethane possesses high thermal stability and flame retardant efficiency, remaining stable at high temperatures and effectively preventing flame spread; brominated epoxy resin exhibits good compatibility and processing properties, allowing for uniform dispersion within the matrix and improving the overall flame retardant performance of the material. The combined use of decabromodiphenyl ethane and brominated epoxy resin leverages their respective advantages to maximize flame retardant performance.

[0013] Preferably, the antioxidant is one or more of antioxidant 168, antioxidant 1010, antioxidant 1076, and antioxidant 1035.

[0014] In the above technical solution, by adding the antioxidants to the EVA composite material, they can effectively prevent the material from degrading due to oxidation during processing and use, thereby improving the material's weather resistance and service life.

[0015] Preferably, the mass ratio of triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotridecyl alcohol polyoxyethylene ether is 3:1.7:1.4.

[0016] In the above technical solution, by adjusting the mass ratio of triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotridecyl alcohol polyoxyethylene ether, the uniformity of inorganic flame retardants in EVA composite materials can be further improved, the flame retardant and smoke-suppressing properties of EVA composite materials can be further optimized, and the overall performance of the material can be improved.

[0017] Secondly, the preparation method of the heat-resistant, flame-retardant, and environmentally friendly EVA composite material provided in this application adopts the following technical solution:

[0018] A method for preparing a heat-resistant, flame-retardant, and environmentally friendly EVA composite material includes the following steps:

[0019] Step 1: Mix all the raw materials and put them into the mixing tank. Turn on the stirring. After stirring evenly, the material can be released and sent to the production workshop. Step 2: Preheat the machine in the production workshop to 200-220℃ and keep it at that temperature for 1.5-2 hours. Then, the material obtained in Step 1 can be put into the machine hopper to start extrusion.

[0020] Step 3: Adjust the clamping pressure to 18% kg and blow mold with 6 kg air pressure.

[0021] Preferably, the stirring speed in step 1 is 800 r / min.

[0022] In the above technical solution, this application ensures the uniformity and stability of the EVA composite material through the above preparation process. The stirring speed in step 1 is 800 r / min, which can effectively promote the mixing and dispersion of the raw materials, laying a good foundation for subsequent processing and molding. The temperature control and pressure adjustment in steps 2 and 3 ensure the stability and uniformity of the material during extrusion and blow molding, thereby obtaining a heat-resistant, flame-retardant, and environmentally friendly EVA composite material with good comprehensive performance.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. In this application, triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotridecyl alcohol polyoxyethylene ether work synergistically to enhance interfacial compatibility and dispersibility, forming a denser and more uniform layer structure. They can also hinder heat transfer paths, promote the development of the carbonized layer, and significantly improve the flame retardancy and smoke suppression properties of EVA composite materials.

[0025] 2. This application selects aluminum hydroxide, magnesium hydroxide and aluminum borate whiskers as inorganic flame retardants for EVA composite materials. By using aluminum hydroxide, magnesium hydroxide and aluminum borate whiskers in combination, the flame retardant performance is effectively improved. At the same time, the addition of aluminum borate whiskers can further enhance the mechanical strength and heat resistance of EVA composite materials, so that EVA composite materials can still maintain excellent physical and chemical properties in high temperature environments. Detailed Implementation

[0026] To better illustrate the purpose, technical solution, and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0027] Example 1

[0028] A heat-resistant, flame-retardant, and environmentally friendly EVA composite material comprises the following raw materials in parts by weight: 35 kg of ethylene-vinyl acetate copolymer, 15 kg of low-density polyethylene, 20 kg of halogenated flame retardant, 15 kg of inorganic flame retardant, 8 kg of maleic anhydride-grafted ethylene-ethyl acrylate copolymer, 3 kg of triethylene glycol diisooctanoate, 1.7 kg of octadecyl alcohol polyoxyethylene ether, 1.4 kg of isotridecyl alcohol polyoxyethylene ether, and 2 kg of antioxidant.

[0029] The halogenated flame retardant is a mixture of decabromodiphenyl ethane and brominated epoxy resin in a mass ratio of 1:0.4.

[0030] The inorganic flame retardant is a mixture of aluminum hydroxide, magnesium hydroxide and aluminum borate whiskers in a mass ratio of 1:1:0.4.

[0031] Among them, the antioxidant is antioxidant 1010.

[0032] The ethylene-vinyl acetate copolymer was purchased from ExxonMobil in the United States, with the grade UL15019CC.

[0033] The low-density polyethylene was purchased from Lanzhou Petrochemical, product number: LDPE 2426H.

[0034] Among them, decabromodiphenyl ethane was purchased from Henan Duohui Chemical Products Co., Ltd.

[0035] The brominated epoxy resin was purchased from Hubei Xingyan New Material Technology Co., Ltd.

[0036] The aluminum hydroxide was purchased from Shijiazhuang Baijiang Mineral Products Co., Ltd.

[0037] The magnesium hydroxide was purchased from Jinan Henghan Chemical Co., Ltd.

[0038] The aluminum borate whiskers were purchased from Hubei Watson Chemical Technology Co., Ltd.

[0039] The maleic anhydride-grafted ethylene-ethyl acrylate copolymer was purchased from DuPont, USA, with the grade: 21E830.

[0040] Among them, triethylene glycol diisooctanoate was purchased from Shandong Xuchen Chemical Technology Co., Ltd.

[0041] Among them, octadecyl alcohol polyoxyethylene ether was purchased from Wuhan Kanos Technology Co., Ltd.

[0042] The isomeric tridecyl alcohol polyoxyethylene ether was purchased from Jining Tangyi Chemical Co., Ltd., item number: E-1320.

[0043] Antioxidant 1010 was purchased from BASF in Germany.

[0044] The preparation method of the heat-resistant, flame-retardant, and environmentally friendly EVA composite material includes the following steps:

[0045] Step 1: Mix all raw materials and put them into the mixing tank. Turn on the mixer at a speed of 800 r / min. After mixing evenly, the material can be discharged and sent to the production workshop.

[0046] Step 2: The machine in the production workshop is preheated to 200-220℃ and kept at that temperature for 1.5-2 hours before the material obtained in Step 1 is fed into the machine hopper to begin extrusion.

[0047] Step 3: Adjust the clamping pressure to 18% kg and blow mold with 6 kg air pressure.

[0048] Example 2

[0049] A heat-resistant, flame-retardant, and environmentally friendly EVA composite material, which differs from Example 1 in that it comprises the following raw materials in parts by weight: 30 kg ethylene-vinyl acetate copolymer, 20 kg low-density polyethylene, 15 kg halogenated flame retardant, 20 kg inorganic flame retardant, 5 kg maleic anhydride-grafted ethylene-ethyl acrylate copolymer, 2 kg triethylene glycol diisooctyl ester, 2 kg octadecyl alcohol polyoxyethylene ether, 2 kg isotridecyl alcohol polyoxyethylene ether, and 1 kg antioxidant.

[0050] The halogenated flame retardant is a mixture of decabromodiphenyl ethane and brominated epoxy resin in a mass ratio of 1:0.3.

[0051] The inorganic flame retardant is a mixture of aluminum hydroxide, magnesium hydroxide and aluminum borate whiskers in a mass ratio of 1:1.2:0.1.

[0052] The preparation method of the heat-resistant, flame-retardant, and environmentally friendly EVA composite material includes the following steps:

[0053] Step 1: Mix all raw materials and put them into the mixing tank. Turn on the mixer at a speed of 800 r / min. After mixing evenly, the material can be discharged and sent to the production workshop.

[0054] Step 2: The machine in the production workshop is preheated to 200℃ and kept at that temperature for 2 hours before the material obtained in Step 1 is fed into the machine hopper to begin extrusion.

[0055] Step 3: Adjust the clamping pressure to 18% kg and blow mold with 6 kg air pressure.

[0056] Example 3

[0057] A heat-resistant, flame-retardant, and environmentally friendly EVA composite material, which differs from Example 1, includes the following raw materials in parts by weight: 40 kg ethylene-vinyl acetate copolymer, 10 kg low-density polyethylene, 25 kg halogenated flame retardant, 10 kg inorganic flame retardant, 10 kg maleic anhydride-grafted ethylene-ethyl acrylate copolymer, 4 kg triethylene glycol diisooctanoate, 1 kg octadecyl alcohol polyoxyethylene ether, 1 kg isotridecyl alcohol polyoxyethylene ether, and 3 kg antioxidant.

[0058] The halogenated flame retardant is a mixture of decabromodiphenyl ethane and brominated epoxy resin in a mass ratio of 1:0.5.

[0059] The inorganic flame retardant is a mixture of aluminum hydroxide, magnesium hydroxide and aluminum borate whiskers in a mass ratio of 1:0.8:0.5.

[0060] The preparation method of the heat-resistant, flame-retardant, and environmentally friendly EVA composite material includes the following steps:

[0061] Step 1: Mix all raw materials and put them into the mixing tank. Turn on the mixer at a speed of 800 r / min. After mixing evenly, the material can be discharged and sent to the production workshop.

[0062] Step 2: The machine in the production workshop is preheated to 220℃ and kept at that temperature for 1.5 hours before the material obtained in Step 1 is fed into the machine hopper to begin extrusion.

[0063] Step 3: Adjust the clamping pressure to 18% kg and blow mold with 6 kg air pressure.

[0064] Example 4

[0065] A heat-resistant, flame-retardant, and environmentally friendly EVA composite material, which differs from Example 1 in that the inorganic flame retardant is a mixture of aluminum hydroxide and magnesium hydroxide in a 1:1 mass ratio.

[0066] Comparative Example 1

[0067] An EVA composite material, which differs from Example 1 in that triethylene glycol diisooctanoate is replaced in equal amounts with diisononyl phthalate.

[0068] Comparative Example 2

[0069] An EVA composite material, which differs from Example 1 in that octadecyl alcohol polyoxyethylene ether is replaced in equal amounts with sodium dodecyl sulfate.

[0070] Comparative Example 3

[0071] An EVA composite material, which differs from Example 1 in that an equal amount of isomeric tridecyl alcohol polyoxyethylene ether is replaced with sodium dodecylbenzenesulfonate.

[0072] Comparative Example 4

[0073] An EVA composite material, unlike Example 1, does not contain triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotridecyl alcohol polyoxyethylene ether.

[0074] Performance testing

[0075] The thermal stability, combustion performance, and mechanical properties of the EVA composite materials in the above embodiments and comparative examples were tested.

[0076] Thermal stability: The residual rate (%) after material decomposition was measured using a thermogravimetric analyzer under different atmospheres. The test conditions were a nitrogen atmosphere, a heating rate of 20℃ / min, and a temperature range from room temperature to 600℃.

[0077] Combustion performance: Limiting oxygen index (LOI / %) was tested according to GB / T 2406-2009; vertical burning rating was tested according to GB / T 2408-2008. Mechanical properties: Elongation at break (%) was tested according to GB / T 16421-1996. The elongation at break test data are as follows:

[0078] The test results are shown in Table 1.

[0079] Table 1:

[0080]

[0081]

[0082] Based on the analysis of the experimental results in Table 1, it can be seen that the heat-resistant, flame-retardant, and environmentally friendly EVA composite materials in Examples 1 to 4 all exhibit good performance in terms of thermal stability, combustion performance, and mechanical properties. This indicates that the EVA composite materials in Examples 1 to 4 have good thermal stability, decomposition resistance, flame retardancy, and flexibility.

[0083] Based on the analysis of the EVA composite materials in Examples 1 and 4, compared with Example 1, the inorganic flame retardant in Example 4 only contains aluminum hydroxide and magnesium hydroxide, without the addition of aluminum borate whiskers. The combustion performance and mechanical properties of Example 1 are good, which further proves the important role of aluminum borate whiskers in improving the flame retardant and mechanical properties of EVA composite materials.

[0084] Analysis of the EVA composite materials from Examples 1 and Comparative Examples 1-4 shows that, in Examples 1-4, triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotrimethylene glycol polyoxyethylene ether were replaced or not added, respectively. Example 1 exhibited good thermal stability, combustion performance, and mechanical properties. This indicates that the combined use of triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotrimethylene glycol polyoxyethylene ether plays a crucial role in improving the overall performance of the EVA composite material. By optimizing the dispersibility and compatibility of inorganic flame retardants in the substrate, triethylene glycol diisooctanoate, octadecyl alcohol polyoxyethylene ether, and isotrimethylene glycol polyoxyethylene ether not only improve the flame retardant and smoke-suppressing properties of the material but also enhance its mechanical properties and thermal stability.

[0085] 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. A heat-resistant, flame-retardant, environmentally friendly EVA composite material, characterized in that, The raw materials include the following mass fractions: 30-40 parts of ethylene-vinyl acetate copolymer, 10-20 parts of low-density polyethylene, 15-25 parts of halogen-based flame retardant, 10-20 parts of inorganic flame retardant, 5-10 parts of maleic anhydride grafted ethylene-ethyl acrylate copolymer, 2-4 parts of triethylene glycol diisooctylate, 1-2 parts of octadecanol polyoxyethylene ether, 1-2 parts of isomeric tridecanol polyoxyethylene ether, and 1-3 parts of antioxidant. 2.The heat-resistant, flame-retardant, and environmentally friendly EVA composite material of claim 1, characterized in that, The inorganic flame retardant is a mixture of aluminum hydroxide, magnesium hydroxide, and aluminum borate whiskers, and the mass ratio of the aluminum hydroxide, magnesium hydroxide, and aluminum borate whiskers is 1: (0.8-1.2): (0.1-0.5). 3.The heat-resistant, flame-retardant, and environmentally friendly EVA composite material of claim 1, characterized in that, The halogen-based flame retardant is one or more of decabromodiphenyl ethane and brominated epoxy resin. 4.The heat-resistant, flame-retardant, and environmentally friendly EVA composite material of claim 1, characterized in that, The halogen-based flame retardant is a mixture of decabromodiphenyl ethane and brominated epoxy resin in a mass ratio of 1: (0.3-0.5). 5.The heat-resistant, flame-retardant, and environmentally friendly EVA composite material of claim 1, characterized in that, The antioxidant is one or more of antioxidant 168, antioxidant 1010, antioxidant 1076, and antioxidant 1035. 6.The heat-resistant, flame-retardant, and environmentally friendly EVA composite material of claim 1, characterized in that, The mass ratio of the triethylene glycol diisooctylate, octadecanol polyoxyethylene ether, and isomeric tridecanol polyoxyethylene ether is 3:1.7:1.

4.

7. A preparation method of a heat-resistant, flame-retardant, and environmentally friendly EVA composite material, characterized in that, The method includes the following steps: Step 1: The raw materials are mixed and put into a mixing cylinder, and stirring is started. After uniform stirring, the material is discharged and sent to the production workshop. Step 2: The machine in the production workshop is preheated to 200-220℃, and after maintaining the temperature for 1.5-2 hours, the material obtained in step 1 is normally put into the machine hopper to start extrusion. Step 3: The mold locking pressure is adjusted to 18 kg, and blow molding is performed at a gas pressure of 6 kg. 8.The preparation method of the heat-resistant, flame-retardant, and environmentally friendly EVA composite material of claim 7, characterized in that, The stirring speed in step 1 is 800 r / min.

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