Production process of modified EVA material and EVA film

Abstract

The invention relates to the field of packaging materials, and particularly discloses a production process of a modified EVA (Ethylene Vinyl Acetate) material and an EVA film. The modified EVA material is prepared from the following components in parts by weight: 70-90 parts of EVA; 6 to 10 parts of HDPE (high-density polyethylene); 10 to 15 parts of LLDPE (linear low density polyethylene); and 5-10 parts of an auxiliary agent. The production process of the EVA film comprises the following steps: mixing 70-90 parts of EVA, 6-10 parts of HDPE (High-Density Polyethylene), 10-15 parts of LLDPE (Linear Low-Density Polyethylene) and 5-10 parts of an auxiliary agent, putting into an extruder, extruding, calendering to form a film, and carrying out negative pressure cooling to obtain the EVA film. According to the modified EVA material provided by the invention, the EVA is taken as a main component, and HDPE and LLDPE are added for blending, so that an ideal heat sealing effect is realized, the heat sealing fastness reaches the standard, the transparency is high, the printability is good, and the modified EVA material is suitable for preparing EVA packaging bags.

Description

Technical Field

[0001] The present application relates to the field of packaging materials, and more specifically, to a production process of a modified EVA material and an EVA film. Background Art

[0002] Packaging bags refer to bags used to package goods for transportation, storage and sales, and are widely used in daily life and industrial production. For conventional power tool accessories such as drill bits, PVC high-frequency bags are often used as packaging bags. PVC high-frequency bags are produced through high-frequency hot pressing technology, with reliable sealing, high sealing, and no obvious marks or seams, suitable for large-scale automated production.

[0003] EVA refers to ethylene-vinyl acetate copolymer, which is an environmentally friendly material and will not cause pollution to the environment when it is discarded. Currently, the only thermoplastic plastic that uses high-frequency hot pressing technology is PVC material. In comparison, although EVA material is more environmentally friendly, it is difficult to use because its heat-sealing strength does not meet the standards. For this reason, it is necessary to develop an EVA material that can be heat-sealed and meets environmental protection requirements for the preparation of EVA packaging bags. Summary of the invention

[0004] In order to ensure that the heat-sealing fastness of EVA materials meets the standards, the present application provides a production process for a modified EVA material and an EVA film.

[0005] In the first aspect, the present application provides a modified EVA material, which adopts the following technical solution: A modified EVA material is made from the following components in parts by weight: EVA 70-90 parts; HDPE 6-10 parts; LLDPE 10-15 parts; 5-10 parts of additives.

[0006] By adopting the above technical solution, EVA as the main component has good transparency and glossiness. By introducing vinyl acetate monomer into the molecular chain, the crystallinity is reduced and the toughness, impact resistance, filler solubility and heat sealing performance are improved.

[0007] HDPE is high-density polyethylene, with short and tightly arranged molecular chains and high crystallinity, so it has good tensile strength and impact resistance. HDPE is non-hygroscopic and has good water vapor resistance, making it suitable for making packaging materials. In addition, HDPE has good heat resistance and cold resistance, good chemical stability, and is also an environmentally friendly material that can be recycled and reused after heating to the melting point. However, the transparency of HDPE is relatively low, usually appearing translucent or opaque, and is not suitable as the main component of transparent packaging bags.

[0008] LLDPE, or linear low-density polyethylene, is a synthetic resin obtained by polymerizing ethylene with higher α-olefins (such as butene-1 and hexene-1) under low pressure. LLDPE has high tensile strength, excellent impact resistance and first-class puncture resistance. Compared with LDPE, LLDPE has higher softening temperature and melting temperature, high strength, good toughness, high rigidity, good heat resistance and cold resistance. During the extrusion process, LLDPE's lower shear sensitivity leads to faster stress relaxation of the polymer chain, so the physical properties are less sensitive to changes in the blow molding ratio, and it is easier to make thinner films while maintaining high strength and toughness. But at the same time, LLDPE has poor transparency and is not suitable as the main component of transparent packaging bags.

[0009] The modified EVA material provided in the present application takes EVA as the main component, and HDPE and LLDPE are added for blending. The EVA is modified so that the molecular weight of the polymer is increased and the viscosity and flow state are improved. Under the action of heat sealing temperature and pressure, the polymer chain segments penetrate and diffuse with each other to achieve an ideal heat sealing effect. The heat sealing fastness meets the standard, and the material has high transparency and good printability, and is suitable for preparing EVA packaging bags.

[0010] Optionally, the VA content of the EVA is 16-20%.

[0011] By adopting the above technical solution, the VA content, i.e. the vinyl acetate content, has a significant effect on the performance of EVA materials. As the VA content increases, the crystallinity of EVA decreases, the hardness and tensile strength decrease accordingly, the flexibility and impact resistance increase, and the heat deformation resistance and chemical resistance decrease. In addition, as the VA content increases, the compatibility of EVA with other polymers increases, and the printability and electrical insulation properties improve.

[0012] In the past, EVA plastic films mostly used 1-15% VA content. Based on the consideration of good polymer compatibility, this application selects a VA content range of 16-20%, so that EVA can be better compatible with HDPE and LLDPE, and has good printability and transparency. Although EVA with 16-20% VA content is inferior to EVA with 1-15% VA content in mechanical properties such as tensile strength, after compounding with HDPE and LLDPE, the mechanical properties are sufficient to meet the needs of packaging films.

[0013] Optionally, the auxiliary agent includes a plasticizer, an antioxidant, a filler and a compatibilizer.

[0014] By adopting the above technical solution, the main function of the plasticizer is to improve the flexibility and processing performance of the EVA material. It can accelerate the melting speed and reduce the melt viscosity of the EVA material, thereby improving the flexibility and cold resistance of the material.

[0015] Antioxidants can prevent free radicals from initiating reactions and prevent EVA macromolecular chains from absorbing ultraviolet rays and undergoing physical and chemical changes, thereby avoiding the degradation of EVA material performance, such as preventing EVA from yellowing and degradation of bonding properties.

[0016] Fillers are mainly used to reduce the cost of EVA film materials, and can also improve certain physical properties of the material. Fillers can reduce the shrinkage of EVA during solidification, change the crystallization rate, prevent glue penetration, and improve the heat resistance of EVA. The amount of filler added in the present application is small, which prevents the melt viscosity of EVA from increasing, avoids affecting its wettability and initial adhesion, and thus ensures the heat-sealing strength.

[0017] There is a certain degree of compatibility between EVA and LLDPE, but phase separation may occur when EVA and HDPE are mixed, affecting the performance of the material. The role of the compatibilizer is to promote the combination of two incompatible polymers to form a stable blend. In the modified EVA material, the compatibilizer can reduce the surface tension between EVA, HDPE and LLDPE, promote phase dispersion, increase the adhesion between phases, and thus improve the comprehensive performance of the EVA film material, such as improving its toughness and processing performance.

[0018] This application uses a variety of additives to ensure the comprehensive performance of EVA materials.

[0019] Optionally, the preparation process of the compatibilizer is as follows: The first step is to heat maleic anhydride to 65-70°C until it melts, and then add isopropanol, the molar ratio of maleic anhydride to isopropanol is (1-1.1):1, and after the addition is completed, continue to heat to 80-85°C, keep warm and react for 1-2h to obtain isopropyl maleate; In the second step, 25-30 parts of isopropyl maleate and 100-120 parts of water are mixed by weight, the temperature is raised to 80-90°C, 13-17 parts of acrylic acid and 3-4 parts of ammonium persulfate are added, the mixture is mixed evenly, the mixture is kept warm for reaction for 2-3 hours, the temperature is then lowered to room temperature, and the compatibilizer is obtained.

[0020] By adopting the above technical solution, compared with the commonly used compatibilizers on the market, the self-made compatibilizer of the present application has a superior effect on promoting the compatibility of EVA and HDPE, has a significant improvement effect on the processing rheological properties of the polymer, and can ensure that the EVA material has good heat-sealing strength.

[0021] Optionally, in the second step of the preparation process of the compatibilizer, 2-3 parts by weight of sodium alginate are added together with acrylic acid.

[0022] By adopting the above technical solution, the addition of sodium alginate plays a role in controlling the reaction rate, which is beneficial to improving the polymerization yield and further improving the effect of the compatibilizer.

[0023] Optionally, the antioxidant is a compound of antioxidant 1076 and antioxidant 1010.

[0024] By adopting the above technical solution, antioxidant 1076 and antioxidant 1010 are both common antioxidants available on the market, the raw materials are easily available, the formation of coloring groups is effectively inhibited, and the transparency of the film is less rigid.

[0025] Optionally, the plasticizer is ginkgo nut oil.

[0026] By adopting the above technical solution, compared with common plasticizers such as soybean oil and DOP, ginkgo nut oil has good compatibility with the copolymers of EVA, LLDPE and HDPE of the present application, which is conducive to improving the toughness of EVA materials and is suitable for manufacturing transparent packaging bags. In addition, the addition of ginkgo nut oil is conducive to better adhesion of printing ink to the surface of the film, thereby improving the printing quality.

[0027] Optionally, the filler is compounded from calcium carbonate whiskers and talcum powder.

[0028] By adopting the above technical solution, calcium carbonate whiskers and talcum powder are used as fillers, which have little effect on the transparency of the film and can ensure that the EVA material has excellent mechanical properties. In addition, the use of calcium carbonate can improve the surface anti-slip property of the film, help improve the ink transfer efficiency during printing, and thus improve printability.

[0029] In a second aspect, the present application provides a production process of an EVA film, which adopts the following technical solution: A production process of an EVA film comprises the following steps: 70-90 parts of EVA, 6-10 parts of HDPE, 10-15 parts of LLDPE and 5-10 parts of an auxiliary agent are mixed and put into an extruder, after extrusion, the mixture is calendered into a film, and then negative pressure cooling is performed to obtain the EVA film.

[0030] By adopting the above technical solution, the cooling efficiency of negative pressure cooling is high, and heat can be removed from the surface of the film more quickly, thereby improving production efficiency and film quality.

[0031] Optionally, the temperature of the extruder is set to 140-160°C, 180-200°C, 200-220°C, 210-230°C in sequence from the direction of feeding to the direction of discharging.

[0032] By adopting the above technical solution, the setting of four temperature intervals is suitable for the EVA material formula of this application.

[0033] In summary, this application has the following beneficial effects: 1. The modified EVA material provided in the present application uses EVA as the main component, and HDPE and LLDPE are added for blending to modify the EVA, so that the molecular weight of the polymer is increased, the viscosity and flow state are improved, and under the action of heat-sealing temperature and pressure, the polymer chain segments penetrate and diffuse with each other to achieve an ideal heat-sealing effect, the heat-sealing fastness meets the standard, and the transparency is high and the printability is good, so the EVA material is suitable for preparing EVA packaging bags; 2. The additives of the present application are plasticizers, antioxidants, fillers and compatibilizers, which are compounded and added to ensure the comprehensive performance of the EVA material; in particular, the homemade compatibilizer has a good effect on promoting the compatibility between EVA, HDPE and LLDPE. DETAILED DESCRIPTION

[0034] The present application is further described in detail below in conjunction with the examples. It is particularly noted that if no specific conditions are specified in the following examples, the experiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following examples can be obtained from common commercial sources.

[0035] Preparation Example 1: The preparation process of the compatibilizer is as follows: In the first step, maleic anhydride is heated to 65°C until it melts, and then isopropanol is added, the molar ratio of maleic anhydride to isopropanol is 1:1, and after the addition is completed, the temperature is continued to rise to 80°C, and the temperature is kept for reaction for 1 hour to obtain isopropyl maleate; In the second step, 25 kg of isopropyl maleate and 100 kg of water were mixed, the temperature was raised to 80° C., 13 kg of acrylic acid and 3 kg of ammonium persulfate were added, the mixture was mixed evenly, and the mixture was kept warm for 2 hours, and then the temperature was lowered to room temperature to obtain a compatibilizer.

[0036] Preparation Example 2: The preparation process of the compatibilizer is as follows: In the first step, maleic anhydride is heated to 70°C until it melts, and isopropanol is added, the molar ratio of maleic anhydride to isopropanol is 1.1:1, and after the addition is completed, the temperature is continued to rise to 85°C, and the temperature is kept for reaction for 2 hours to obtain isopropyl maleate; In the second step, 30 kg of isopropyl maleate and 120 kg of water were mixed, the temperature was raised to 90° C., 17 kg of acrylic acid and 4 kg of ammonium persulfate were added, the mixture was evenly mixed and the mixture was kept warm for reaction for 3 hours, and then the mixture was cooled to room temperature to obtain a compatibilizer.

[0037] Preparation Example 3: The preparation process of the compatibilizer is as follows: In the first step, maleic anhydride is heated to 68°C until it melts, and isopropanol is added, the molar ratio of maleic anhydride to isopropanol is 1.05:1, and after the addition is completed, the temperature is continued to be raised to 83°C, and the temperature is kept for reaction for 1.5 hours to obtain isopropyl maleate; In the second step, 28 kg of isopropyl maleate and 110 kg of water were mixed, the temperature was raised to 85° C., 15 kg of acrylic acid and 3.5 kg of ammonium persulfate were added, the mixture was mixed evenly, and the mixture was kept warm for reaction for 2.5 hours, and then the temperature was lowered to room temperature to obtain a compatibilizer.

[0038] Preparation Example 4: The preparation process of the compatibilizer is as follows: In the first step, maleic anhydride is heated to 68°C until it melts, and isopropanol is added, the molar ratio of maleic anhydride to isopropanol is 1.05:1, and after the addition is completed, the temperature is continued to be raised to 83°C, and the temperature is kept for reaction for 1.5 hours to obtain isopropyl maleate; In the second step, 28 kg of isopropyl maleate and 110 kg of water were mixed, the temperature was raised to 85°C, and then 15 kg of acrylic acid, 2 kg of sodium alginate and 3.5 kg of ammonium persulfate were added. After mixing evenly, the mixture was kept warm for 2.5 hours, and then the temperature was lowered to room temperature to obtain a compatibilizer.

[0039] Preparation Example 5: The preparation process of the compatibilizer is as follows: In the first step, maleic anhydride is heated to 68°C until it melts, and isopropanol is added, the molar ratio of maleic anhydride to isopropanol is 1.05:1, and after the addition is completed, the temperature is continued to be raised to 83°C, and the temperature is kept for reaction for 1.5 hours to obtain isopropyl maleate; In the second step, 28 kg of isopropyl maleate and 110 kg of water were mixed, the temperature was raised to 85°C, and then 15 kg of acrylic acid, 3 kg of sodium alginate and 3.5 kg of ammonium persulfate were added. After mixing evenly, the mixture was kept warm for 2.5 hours, and then the temperature was lowered to room temperature to obtain a compatibilizer.

[0040] Preparation Example 6: The preparation process of Ginkgo Biloba Oil is as follows: Peel and core the ginkgo nuts, grind them into powder, and pass them through a 100-mesh sieve to obtain ginkgo powder; Put ginkgo powder into the extraction kettle, adjust the temperature to 5°C, turn on the carbon dioxide pump, and the pressure is 15Mpa. After passing through the extraction kettle, the carbon dioxide enters the first and second separation kettles connected in series to obtain ginkgo nut oil. The temperature of the first separation kettle is controlled at 15°C and the pressure is controlled at 2.5MPa. The temperature of the second separation kettle is controlled at 25°C and the pressure is controlled at 3.5Mpa. Then the carbon dioxide is refrigerated and compressed and returned to the gas storage tank. The extraction cycle is repeated for 12 hours to release ginkgo nut oil from the two separation kettles.

[0041] Embodiment 1: A modified EVA material is made of components comprising the following qualities: EVA 70kg, brand V5110F, purchased from BASF-Yangzi; 6kg HDPE, brand 5301AA, purchased from Shanghai Secco; LLDPE 10kg, brand LL0209AA, purchased from Shanghai Secco; 5kg of additives, including 30wt% of plasticizer, 5wt% of antioxidant, 40wt% of filler and 25wt% of compatibilizer.

[0042] The plasticizer is the ginkgo nut oil prepared in Preparation Example 6, the antioxidant is compounded by antioxidant 1076 and antioxidant 1010 of equal quality, the filler is compounded by calcium carbonate whisker and talc of equal quality, and the compatibilizer is prepared in Preparation Example 1.

[0043] A production process of an EVA film comprises the following steps: According to the above ratio, EVA, HDPE, LLDPE, plasticizer, antioxidant, filler and compatibilizer are mixed and put into the extruder. The temperature of the extruder is set to 150°C, 190°C, 210°C and 220°C in the direction from feed to discharge. After extrusion, it is calendered into a film and then cooled under negative pressure to obtain an EVA film.

[0044] Embodiment 2: A modified EVA material is made of components comprising the following qualities: EVA 90kg, brand V5110F, purchased from BASF-Yanzi; HDPE 10kg, brand 5301AA, purchased from Shanghai Secco; LLDPE 15kg, brand LL0209AA, purchased from Shanghai Secco; 10kg of additives, including 30wt% plasticizer, 5wt% antioxidant, 40wt% filler and 25wt% compatibilizer.

[0045] The plasticizer is the ginkgo nut oil prepared in Preparation Example 6, the antioxidant is compounded by antioxidant 1076 and antioxidant 1010 of equal quality, the filler is compounded by calcium carbonate whisker and talc of equal quality, and the compatibilizer is prepared in Preparation Example 2.

[0046] A production process of an EVA film comprises the following steps: According to the above ratio, EVA, HDPE, LLDPE, plasticizer, antioxidant, filler and compatibilizer are mixed and put into the extruder. The temperature of the extruder is set to 150°C, 190°C, 210°C and 220°C in the direction from feed to discharge. After extrusion, it is calendered into a film and then cooled under negative pressure to obtain an EVA film.

[0047] Embodiment 3: A modified EVA material is made of components comprising the following qualities: EVA 80kg, brand V5110F, purchased from BASF-Yanzi; 8kg HDPE, brand 5301AA, purchased from Shanghai Secco; LLDPE 12kg, brand LL0209AA, purchased from Shanghai Secco; 7kg of additives, including 30wt% plasticizer, 5wt% antioxidant, 40wt% filler and 25wt% compatibilizer.

[0048] The plasticizer is the ginkgo nut oil prepared in Preparation Example 6, the antioxidant is compounded by antioxidant 1076 and antioxidant 1010 of equal quality, the filler is compounded by calcium carbonate whisker and talc of equal quality, and the compatibilizer is prepared in Preparation Example 3.

[0049] A production process of an EVA film comprises the following steps: According to the above ratio, EVA, HDPE, LLDPE, plasticizer, antioxidant, filler and compatibilizer are mixed and put into the extruder. The temperature of the extruder is set to 150°C, 190°C, 210°C and 220°C in the direction from feed to discharge. After extrusion, it is calendered into a film and then cooled under negative pressure to obtain an EVA film.

[0050] Embodiment 4: The only difference from Example 3 is that the compatibilizer is prepared by Preparation Example 4.

[0051] Embodiment 5: The only difference from Example 3 is that the compatibilizer is prepared by Preparation Example 5.

[0052] Embodiment 6: The only difference from Example 3 is that the auxiliary agent does not include a compatibilizer, and is composed of 40 wt % of a plasticizer, 5 wt % of an antioxidant, and 55 wt % of a filler.

[0053] Embodiment 7: The only difference from Example 3 is that the plasticizer is dioctyl phthalate.

[0054] Embodiment 8: The only difference from Example 3 is that the plasticizer is commercially available epoxidized soybean oil.

[0055] Embodiment 9: The only difference from Example 3 is that the filler is only talc.

[0056] Comparative Example 1: The only difference from Example 3 is that no HDPE is added.

[0057] Comparative Example 2: The only difference from Example 3 is that no LLDPE is added.

[0058] Comparative Example 3: The only difference from Example 3 is that no HDPE and LLDPE are added, and the additive does not include a compatibilizer, and is composed of 40% plasticizer, 5wt% antioxidant and 55wt% filler.

[0059] Comparative Example 4: The only difference from Example 3 is that the EVA is V4110J, purchased from BASF-Yangzi, and has a VA content of 14%.

[0060] Performance testing: The ink adhesion of the EVA films of Examples 1-9 and Comparative Examples 1-4 was tested with reference to the disc peeling method described in GB / T 13217.7-2023 "Test Method for Ink Adhesion". The adhesion was expressed as the degree of tape adhesion or damage. The results were expressed in % and recorded in Table 1. The higher the value, the stronger the adhesion.

[0061] The light transmittance of the EVA films of Examples 1-9 and Comparative Examples 1-4 was tested with reference to the method described in GB / T 2410-2008 "Determination of light transmittance and haze of transparent plastics", and the ratio of the luminous flux passing through the sample to the luminous flux incident on the sample was recorded. The results were expressed in % and recorded in Table 1. The higher the value, the more transparent the film.

[0062] The test method for heat seal strength refers to 5.8 Heat seal strength test method in GB / T 10003-2008 "General Purpose Biaxially Oriented Polypropylene (BOPP) Film".

[0063] The specific detection process is as follows: 1. Cut 5 samples evenly in the width direction of the film roll. The sample length is 150 mm and the width is (15 ± 0.1) mm. 2. During the test, fold the sample in half, align the two ends, and place it flat on the welding surface of a high-frequency heat sealer for heat sealing. The heat sealing temperature is 105°C, the frequency is 40MHz, the welding surface pressure is 0.2MPa, and the heat sealing time is 0.5s.

[0064] 3. Take the heat-sealed part of the sample as the center line, and clamp the two ends of the sample on the two fixtures of the testing machine respectively, so that the longitudinal axis of the sample coincides with the center line of the upper and lower fixtures. The clamps are appropriately tight to prevent the sample from slipping and breaking in the fixtures. The distance between the fixtures is 100mm, the test speed is (100±10)mm / min, and the maximum load when the sample breaks is read. If the sample does not break at the heat-sealed part, the sample is invalid and another sample is taken for re-test.

[0065] From Table 1, we can get: 1. Combined with the test results of Examples 1-3, it can be seen that the EVA film of the present application has excellent printability, good transparency and excellent heat-sealing strength, meeting the use requirements of packaging bags; 2. Combining the test results of Example 3 and Comparative Examples 1-4, it can be seen that the present application modifies HDPE, LLDPE and EVA by blending them, which can significantly improve the printability and heat-sealing strength of the film, and due to the small amount of HDPE and LLDPE added, the transparency of the film is slightly affected; 3. Combining the test results of Example 3 and Examples 4-9, it can be seen that the present application further improves the performance of the film by optimizing the selection of plasticizers, compatibilizers and fillers.

[0066] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A modified EVA material, characterized in that: Made from the following components in parts by weight: EVA 70-90 parts; HDPE 6-10 parts; LLDPE 10-15 parts; 5-10 parts of additives.

2. The modified EVA material according to claim 1, characterized in that: The VA content of the EVA is 16-20%.

3. The modified EVA material according to claim 1, characterized in that: The auxiliary agents include plasticizers, antioxidants, fillers and compatibilizers.

4. The modified EVA material according to claim 3, characterized in that: The preparation process of the compatibilizer is as follows: The first step is to heat maleic anhydride to 65-70°C until it melts, and then add isopropanol, the molar ratio of maleic anhydride to isopropanol is (1-1.1):1, and after the addition is completed, continue to heat to 80-85°C, keep warm and react for 1-2h to obtain isopropyl maleate; In the second step, 25-30 parts of isopropyl maleate and 100-120 parts of water are mixed by weight, the temperature is raised to 80-90°C, 13-17 parts of acrylic acid and 3-4 parts of ammonium persulfate are added, the mixture is mixed evenly, the mixture is kept warm for reaction for 2-3 hours, the temperature is then lowered to room temperature, and the compatibilizer is obtained.

5. The modified EVA material according to claim 4, characterized in that: In the second step of the preparation process of the compatibilizer, 2-3 parts by weight of sodium alginate are added together with acrylic acid.

6. The modified EVA material according to claim 4, characterized in that: The antioxidant is prepared by compounding antioxidant 1076 and antioxidant 1010.

7. The modified EVA material according to claim 3, characterized in that: The plasticizer is ginkgo nut oil.

8. The modified EVA material according to claim 3, characterized in that: The filler is prepared by compounding calcium carbonate whiskers and talcum powder.

9. A production process of EVA film, characterized in that: The method comprises the following steps: mixing 70-90 parts of EVA, 6-10 parts of HDPE, 10-15 parts of LLDPE and 5-10 parts of auxiliary agents and feeding the mixture into an extruder, calendering the mixture into a film after extrusion, and then cooling the mixture under negative pressure to obtain an EVA film.

10. The production process of the EVA film according to claim 9, characterized in that: The temperature of the extruder is set to 140-160°C, 180-200°C, 200-220°C, and 210-230°C in sequence from the direction of feeding to the direction of discharging.

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