An EVA hot melt adhesive for packaging and its preparation method

Abstract

The present invention relates to the technical field of hot melt adhesives, and discloses an EVA hot melt adhesive for packaging and a preparation method thereof. The EVA hot melt adhesive comprises the following raw materials: ethylene-vinyl acetate copolymer, tackifier, Fischer-Tropsch wax, maleic anhydride grafted polypropylene wax, modified additive, and high-temperature resistant component. By adding the modified additive, the prepared EVA hot melt adhesive has excellent mechanical properties and antioxidant properties, can avoid the decline of the adhesive performance of the EVA hot melt adhesive due to oxidation in a humid and hot environment, cracks or peeling phenomena, has long-term antioxidant property, and prolongs the service life of the EVA hot melt adhesive. By adding the high-temperature resistant component, a rigid benzoxazole structure is introduced, which has a high molecular bond breaking energy barrier, effectively improves the high-temperature resistance of the EVA hot melt adhesive, and has a flexible chain segment, which can improve the flexibility of the EVA hot melt adhesive, broaden the application range of the EVA hot melt adhesive, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of hot melt adhesives, and specifically relates to an EVA hot melt adhesive for packaging and a preparation method thereof. Background Art

[0002] Hot melt adhesive is a solvent-free thermoplastic adhesive prepared by melting and blending a thermoplastic polymer as a base material with modified additives. Compared with traditional adhesives, hot melt adhesive is solvent-free, pollution-free, non-toxic, water-resistant and non-opening, has a fast curing speed and can be bonded multiple times, and is known as a green adhesive. At room temperature, hot melt adhesive is a solid, and when used, it is heated and melted into a low-viscosity viscous flow state. After being coated on the surface of the adherend substrate and cooled, it can achieve a tight bond with the adherend substrate. It is widely used in the fields of packaging, medical treatment, daily necessities, etc. The materials of hot melt adhesive are divided into two categories: traditional type and biodegradable type. The traditional type of hot melt adhesive uses ethylene-vinyl acetate copolymer (EVA), polyurethane (PU), polyethylene terephthalate (PET), etc. as the base material, and the biodegradable type uses polylactic acid (PLA), polycaprolactone (PCL), etc. as the base material. Ethylene-vinyl acetate copolymer (EVA) hot melt adhesive has strong adhesion to a variety of materials and is inexpensive, and is the most used hot melt adhesive at present. Therefore, it is necessary to research and improve EVA hot melt adhesive.

[0003] When EVA hot melt adhesive is applied to the packaging field, there are still deficiencies. The EVA material has poor flexibility, and when subjected to external forces, the EVA hot melt adhesive is prone to breakage or peeling. In addition, the EVA material belongs to a linear structure and does not have a crosslinked network, and will be deformed by heat in a high-temperature environment, resulting in a weakening of the interaction force between the hot melt adhesive and the adherend substrate, resulting in a decrease in the bonding strength and being easily accelerated aging, resulting in cracks or even peeling of the EVA hot melt adhesive, affecting the service life of the EVA hot melt adhesive. The patent with the publication number CN115216248B discloses an EVA adhesive for paper packaging and a preparation method thereof. The EVA adhesive includes the following raw materials: high molecular polymer ethylene-vinyl acetate copolymer, tackifier, wax, antioxidant, auxiliary agent, additive, deionized water. The prepared EVA adhesive has strong cohesive strength, bonding strength and high temperature resistance, but the improvement effect of the high temperature resistance of the EVA hot melt adhesive in this patent is general and does not have long-term antioxidant performance, which limits the application of the EVA hot melt adhesive to a certain extent. Therefore, the present invention provides an EVA hot melt adhesive for packaging, which can maintain stable performance and long service life in a high-temperature environment, broadens the application range of the EVA hot melt adhesive, and has broad application prospects. Summary of the Invention

[0004] In order to solve the problems mentioned in the background art, the purpose of the present invention is to provide an EVA hot melt adhesive for packaging and a preparation method thereof.

[0005] The object of the present invention can be achieved by the following technical solutions:

[0006] An EVA hot melt adhesive for packaging, comprising the following raw materials in parts by weight: 80-95 parts of ethylene-vinyl acetate copolymer, 10-15 parts of tackifier, 3-6 parts of Fischer-Tropsch wax, 1-3 parts of maleic anhydride grafted polypropylene wax, 3-6 parts of modified additive, and 3-5 parts of high temperature resistant component.

[0007] Further, the tackifier is any one of petroleum resin, terpene resin or rosin resin.

[0008] Further, the preparation method of the modified additive comprises the following steps:

[0009] Step A: Disperse talcum powder in toluene to form a uniform dispersion liquid, introduce nitrogen, raise the temperature to 40-50 °C, add an acyl chloride modifier and a catalyst, react for 2-4 h, then filter, wash and dry to obtain acyl chlorinated talcum powder;

[0010] Step B: Add the acyl chlorinated talcum powder into dimethyl sulfoxide, mix evenly, introduce nitrogen, add 5-aminosalicylic acid, react at room temperature for 4-6 h, then filter, wash and dry to obtain the modified additive.

[0011] By adopting the above technical solution, the surface of the talcum powder contains hydroxyl groups, which can undergo an esterification reaction with the acyl chloride in the structure of the acyl chloride modifier under the action of a catalyst to obtain talcum powder with acyl chloride groups. The acyl chlorinated talcum powder can undergo an amidation reaction with the amino group in the structure of 5-aminosalicylic acid to obtain the modified additive. The modified additive prepared by the present invention organically modifies the talcum powder, reduces the surface energy of the talcum powder, thereby effectively improving the compatibility with the EVA matrix, avoiding the agglomeration phenomenon of the talcum powder in the EVA matrix, making it uniformly dispersed in the EVA matrix, giving play to the advantages of the talcum powder, enhancing the mechanical properties of the EVA hot melt adhesive. In addition, after chemical bonding with 5-aminosalicylic acid, the prepared EVA hot melt adhesive has excellent antioxidant properties. On the one hand, it avoids the precipitation problem of small molecule antioxidant substances, and the EVA hot melt adhesive has long-term antioxidant properties. On the other hand, it also avoids the situation that the EVA hot melt adhesive is easily oxidized resulting in cracks or even peeling on the surface, and prolongs the service life of the EVA hot melt adhesive.

[0012] Further, in step A, the acyl chloride modifier is any one of terephthaloyl chloride, malonyl chloride, succinyl chloride, glutaroyl chloride or adipoyl chloride.

[0013] Further, in step A, the catalyst is triethylamine or pyridine.

[0014] Further, the preparation method of the high temperature resistant component comprises the following steps:

[0015] S1: Add ethylene propylene diene monomer rubber (EPDM) into toluene, and then place the system in a constant temperature water bath with the temperature set at 45 - 55 °C. Stir until the EPDM is dissolved, adjust the pH with formic acid, then slowly add hydrogen peroxide, stir and react for 6 - 8 h, pour into acetone for precipitation, wash the precipitate, and dry it under vacuum to obtain modified EPDM rubber.

[0016] S2: Add the modified EPDM rubber into xylene, mix evenly, introduce nitrogen, add 6 - aminoquinoxaline, raise the temperature to 85 - 100 °C, react for 6 - 8 h, let it cool naturally after the reaction ends, and the product is precipitated, washed, and dried under vacuum to obtain the high - temperature resistant component.

[0017] By adopting the above - mentioned technical solution, under the action of formic acid and hydrogen peroxide, EPDM rubber can be epoxidized and modified to obtain modified EPDM rubber. The epoxy groups in the structure of the modified EPDM rubber can react with the amino groups in the structure of 6 - aminoquinoxaline to obtain the high - temperature resistant component. In the high - temperature resistant component prepared by the present invention, a rigid benzo - nitrogen - containing heterocyclic structure quinoxaline group is introduced. The C=N in its structure has a high bond energy. Therefore, the high - temperature resistant component has a relatively high molecular bond breaking energy barrier and requires absorption of more heat to break or thermally decompose it. In addition, the flexible chain segments in the high - temperature resistant component can effectively improve the flexibility of the EVA hot - melt adhesive, avoiding breakage or peeling when subjected to external forces, resulting in a decrease in bonding performance. The high - temperature resistant component structure contains hydroxyl groups generated by the reaction, which can cross - link with the EVA matrix under the action of maleic anhydride - grafted polypropylene wax to form a network structure. The compactness of the EVA matrix is improved, which can enhance the cohesive strength and has a stronger bonding force with the adherend substrate. At the same time, the improvement of the compactness of the EVA matrix can also prevent the thermal movement of molecular chains, further enhancing the high - temperature resistance of the EVA hot - melt adhesive, enabling the EVA hot - melt adhesive to maintain stable performance in high - temperature environments and broadening the application range of the EVA hot - melt adhesive.

[0018] Further, in S1, the pH is 2 - 3.

[0019] A preparation method of an EVA hot - melt adhesive for packaging, comprising the following steps:

[0020] Step 1: Add ethylene - vinyl acetate copolymer, tackifier, and Fischer - Tropsch wax into a high - speed mixer and mix evenly. Then raise the temperature to 100 - 120 °C and process for 1 - 3 h. After the temperature drops to 80 - 90 °C, add maleic anhydride - grafted polypropylene wax, modified additive, and high - temperature resistant component, set the rotation speed to 100 - 300 r / min, and stir and mix for 1 - 3 h to obtain a mixed material.

[0021] Step 2: Add the mixed materials into a twin-screw extruder. Set the temperature of the inlet section to 80 - 90 °C, the temperature of the middle section to 110 - 125 °C, the temperature of the outlet section to 90 - 100 °C, and the screw speed to 200 - 400 r / min. Then, melt and extrude to granulate, and EVA hot melt adhesive can be obtained.

[0022] Advantages of the present invention:

[0023] By preparing the modified additive and the high-temperature resistant component and adding them into the EVA matrix, the prepared EVA hot melt adhesive has excellent mechanical properties, antioxidant properties, high-temperature resistant properties and flexibility. The tensile strength can reach 31.5 MPa, and the elongation at break can reach 185%. It can maintain stable performance in high-temperature environments, has a long service life, broadens the application scope of EVA hot melt adhesive, and has broad application prospects.

[0024] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. Description of the drawings

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 It is the infrared spectrogram of the modified additive prepared in Example 1 of the present invention. Detailed implementation manners

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0028] Example 1

[0029] Preparation of the modified additive

[0030] Step A: Disperse 3.2 g of talcum powder in toluene to form a uniform dispersion. Introduce nitrogen, raise the temperature to 45 °C, add 2.8 g of malonyl chloride and 0.3 g of triethylamine. After reacting for 3 h, filter, wash, and dry to obtain acylated talcum powder.

[0031] Step B: Add 3 g of acyl chloride-treated talcum powder into dimethyl sulfoxide. After mixing evenly, introduce nitrogen gas, add 2 g of 5-aminosalicylic acid, react for 5 h at room temperature, then perform suction filtration, washing, and drying to obtain the modified additive.

[0032] Sample preparation was carried out by the potassium bromide tablet pressing method. The modified additive was subjected to infrared testing using a Bruker TENSOR II Fourier transform infrared spectrometer. As Figure 1 shown, the spectral wave number test range was 4000 cm -1 -500 cm -1 . Analysis showed that in the infrared spectrum of the modified additive, an absorption peak of the carbon-hydrogen bond in the benzene ring appeared at 3038 cm -1 , an absorption peak of the carbon-oxygen double bond in the ester group appeared at 1746 cm -1 , an absorption peak of the carbon-oxygen double bond in the carboxyl group appeared at 1692 cm -1 , an absorption peak of the carbon-oxygen double bond in the amide appeared at 1669 cm -1 , and an absorption peak of the silicon-oxygen bond of talcum powder appeared at 1018 cm -1 .

[0033] Example 2

[0034] Preparation of the high-temperature resistant component

[0035] S1: Add 3.6 g of ethylene propylene diene monomer (EPDM) into toluene. Immediately place the system in a constant temperature water bath with the temperature set at 50 °C. After stirring until the EPDM is dissolved, adjust the pH to 2 by adding formic acid with a mass fraction of 86%, and then slowly add 1.2 mL of 30% hydrogen peroxide. Stir and react for 8 h, pour into acetone for precipitation, wash the precipitate, and dry it under vacuum to obtain the modified EPDM.

[0036] S2: Add 3.2 g of the modified EPDM into xylene. After mixing evenly, introduce nitrogen gas, add 1 g of 6-aminoquinoxaline, raise the temperature to 95 °C, and react for 6 h. After the reaction ends, let it cool naturally. The product is precipitated, washed, and dried under vacuum to obtain the high-temperature resistant component.

[0037] Using a Perkin-Elmer 2400 elemental analyzer, the elemental content of the high-temperature resistant component was determined. The test results showed that the nitrogen element content in the high-temperature resistant component was 8.79%. Since the modified EPDM does not contain nitrogen element, it can be speculated that the nitrogen element in the high-temperature resistant component is provided by 6-aminoquinoxaline.

[0038] Example 3

[0039] Preparation of EVA hot melt adhesive

[0040] Step 1: Add 80 g of ethylene-vinyl acetate copolymer, 10 g of rosin resin, and 3 g of Fischer-Tropsch wax into a high-speed mixer. After mixing evenly, raise the temperature to 100 °C and process for 1 h. Then, wait for the temperature to drop to 80 °C, and add 1 g of maleic anhydride grafted polypropylene wax, 3 g of the modified additive prepared in Example 1, and 3 g of the high-temperature resistant component prepared in Example 2. Set the rotation speed to 100 r / min and stir and mix for 1 h to obtain a mixed material;

[0041] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 80 °C, the temperature of the middle section to 110 °C, the temperature of the outlet section to 90 °C, and the screw rotation speed to 200 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0042] Example 4

[0043] Preparation of EVA Hot Melt Adhesive

[0044] Step 1: Add 85 g of ethylene-vinyl acetate copolymer, 12 g of rosin resin, and 4 g of Fischer-Tropsch wax into a high-speed mixer. After mixing evenly, raise the temperature to 105 °C and process for 2 h. Then, wait for the temperature to drop to 85 °C, and add 2 g of maleic anhydride grafted polypropylene wax, 4 g of the modified additive prepared in Example 1, and 4 g of the high-temperature resistant component prepared in Example 2. Set the rotation speed to 200 r / min and stir and mix for 1 h to obtain a mixed material;

[0045] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 85 °C, the temperature of the middle section to 115 °C, the temperature of the outlet section to 95 °C, and the screw rotation speed to 300 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0046] Example 5

[0047] Preparation of EVA Hot Melt Adhesive

[0048] Step 1: Add 90 g of ethylene-vinyl acetate copolymer, 14 g of rosin resin, and 5 g of Fischer-Tropsch wax into a high-speed mixer. After mixing evenly, raise the temperature to 110 °C and process for 2 h. Then, wait for the temperature to drop to 90 °C, and add 3 g of maleic anhydride grafted polypropylene wax, 5 g of the modified additive prepared in Example 1, and 5 g of the high-temperature resistant component prepared in Example 2. Set the rotation speed to 250 r / min and stir and mix for 2 h to obtain a mixed material;

[0049] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 85 °C, the temperature of the middle section to 120 °C, the temperature of the outlet section to 95 °C, and the screw rotation speed to 350 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0050] Example 6

[0051] Preparation of EVA Hot Melt Adhesive

[0052] Step 1: Add 95 g of ethylene-vinyl acetate copolymer, 15 g of rosin resin, and 6 g of Fischer-Tropsch wax into a high-speed mixer. After mixing evenly, raise the temperature to 120 °C and process for 3 h. Then, wait for the temperature to drop to 90 °C, and add 3 g of maleic anhydride grafted polypropylene wax, 6 g of the modified additive prepared in Example 1, and 5 g of the high-temperature resistant component prepared in Example 2. Set the rotation speed to 300 r / min and stir and mix for 3 h to obtain a mixed material;

[0053] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 90 °C, the temperature of the middle section to 125 °C, the temperature of the outlet section to 100 °C, and the screw rotation speed to 400 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0054] Comparative Example 1

[0055] Preparation of EVA Hot Melt Adhesive

[0056] Step 1: Add 85 g of ethylene-vinyl acetate copolymer, 12 g of rosin resin, and 4 g of Fischer-Tropsch wax into a high-speed mixer. After mixing evenly, raise the temperature to 105 °C and process for 2 h. Then, wait for the temperature to drop to 85 °C, and add 2 g of maleic anhydride grafted polypropylene wax and 4 g of the modified additive prepared in Example 1. Set the rotation speed to 200 r / min and stir and mix for 1 h to obtain a mixed material;

[0057] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 85 °C, the temperature of the middle section to 115 °C, the temperature of the outlet section to 95 °C, and the screw rotation speed to 300 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0058] Comparative Example 2

[0059] Preparation of EVA Hot Melt Adhesive

[0060] Step 1: Add 85 g of ethylene-vinyl acetate copolymer, 12 g of rosin resin, and 4 g of Fischer-Tropsch wax into a high-speed mixer. After mixing evenly, raise the temperature to 105 °C and process for 2 h. Then, wait for the temperature to drop to 85 °C, and add 2 g of maleic anhydride grafted polypropylene wax and 4 g of the high-temperature resistant component prepared in Example 2. Set the rotation speed to 200 r / min and stir and mix for 1 h to obtain a mixed material;

[0061] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 85 °C, the temperature of the middle section to 115 °C, the temperature of the outlet section to 95 °C, and the screw rotation speed to 300 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0062] Comparative Example 3

[0063] Preparation of EVA Hot Melt Adhesive

[0064] Step 1: Add 85 g of ethylene-vinyl acetate copolymer, 12 g of rosin resin, and 4 g of Fischer-Tropsch wax into a high-speed mixer and mix evenly. After raising the temperature to 105 °C and treating for 2 h, when the temperature drops to 85 °C, add 2 g of maleic anhydride grafted polypropylene wax, 4 g of talc powder, and 4 g of the high-temperature resistant component prepared in Example 2. Set the rotation speed to 200 r / min and stir and mix for 1 h to obtain a mixed material;

[0065] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 85 °C, the temperature of the middle section to 115 °C, the temperature of the outlet section to 95 °C, and the screw rotation speed to 300 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0066] Comparative Example 4

[0067] Preparation of EVA Hot Melt Adhesive

[0068] Step 1: Add 85 g of ethylene-vinyl acetate copolymer, 12 g of rosin resin, and 4 g of Fischer-Tropsch wax into a high-speed mixer and mix evenly. After raising the temperature to 105 °C and treating for 2 h, when the temperature drops to 85 °C, add 2 g of maleic anhydride grafted polypropylene wax, 4 g of the modified additive prepared in Example 1, and 4 g of ethylene propylene diene monomer. Set the rotation speed to 200 r / min and stir and mix for 1 h to obtain a mixed material;

[0069] Step 2: Add the mixed material into a twin-screw extruder. Set the temperature of the inlet section to 85 °C, the temperature of the middle section to 115 °C, the temperature of the outlet section to 95 °C, and the screw rotation speed to 300 r / min. Melt and extrude into pellets to obtain the EVA hot melt adhesive.

[0070] Performance Testing

[0071] The EVA hot melt adhesives prepared in Examples 3 - 6 and Comparative Examples 1 - 4 are made into films through a hot press and then made into samples that meet the test specifications. According to the standard GB / T30776-2014, the tensile strength and elongation at break of the samples are tested to judge the mechanical properties and flexibility of the samples; after placing the samples in an aging oven at 100 °C for 24 h, the tensile strength of the samples is tested again to judge the antioxidant properties of the samples; the EVA hot melt adhesive is placed in a thermogravimetric analyzer to test the decomposition temperature of the EVA hot melt adhesive. Set the heating rate to 10 °C / min and the temperature range to 50 - 500 °C to judge the high-temperature resistance of the EVA hot melt adhesive. The test results of each item are shown in the following table:

[0072]

[0073] As can be analyzed from the above table, the EVA hot melt adhesives prepared in Examples 3-6 of the present invention have excellent mechanical properties, antioxidant properties, flexibility and high temperature resistance. In Comparative Example 1, the high temperature resistant component was not added, and the rigid benzoxazole group quinoxaline group introduced could not be utilized, nor could a cross-linked network structure be formed with the EVA matrix to improve the high temperature resistance of the hot melt adhesive and the flexible segment in the high temperature resistant component structure to enhance flexibility. Therefore, the high temperature resistance and flexibility are poor. Although a modified additive was added, the mechanical properties and antioxidant properties are excellent. In Comparative Example 2, the modified additive was not added, and the antioxidant substance grafted on talc powder could not be utilized to improve the mechanical properties and antioxidant properties of the hot melt adhesive. Therefore, the mechanical properties and antioxidant properties are poor. Although a high temperature resistant component was added, the high temperature resistance and flexibility are excellent. In Comparative Example 3, talc powder was added, and the mechanical properties are poor, probably due to the agglomeration of talc powder in the EVA matrix and the lack of grafting with antioxidant substances. Therefore, the antioxidant property is poor. Although a high temperature resistant component was added, the high temperature resistance and flexibility are excellent. In Comparative Example 4, a modified additive was added, and the mechanical properties and antioxidant properties are excellent. Ethylene propylene diene monomer was added, but no high temperature resistant group was introduced, so the high temperature resistance is poor, and it cannot form a cross-linked network structure with the EVA matrix, resulting in poor flexibility.

[0074] The above content is only an example and illustration of the concept of the present invention. Those skilled in the art of this technology can make various modifications, supplements or use similar methods to replace the specific embodiments described, as long as they do not deviate from the concept of the invention or exceed the scope defined by this claims, they should fall within the protection scope of the present invention.

Claims

1. An EVA hot melt adhesive for packaging, characterized in that: The invention comprises the following raw materials in parts by weight: 80-95 parts of ethylene-vinyl acetate copolymer, 10-15 parts of tackifier, 3-6 parts of Fischer-Tropsch wax, 1-3 parts of maleic anhydride grafted polypropylene wax, 3-6 parts of modified additives, and 3-5 parts of high temperature resistant components; The preparation method of the modified additive comprises the following steps: Step A: dispersing talc powder in toluene to form a uniform dispersion, introducing nitrogen, raising the temperature to 40-50° C., adding an acyl chloride modifier and a catalyst, reacting for 2-4 hours, filtering, washing, and drying to obtain acyl chloride talc powder; Step B: adding talc chloride to dimethyl sulfoxide, mixing evenly, introducing nitrogen, adding 5-aminosalicylic acid, reacting at room temperature for 4-6 hours, filtering, washing, and drying to obtain a modified additive; The preparation method of the high temperature resistant component comprises the following steps: S1: Add EPDM rubber to toluene, then place the system in a constant temperature water tank at 45-55°C, stir until the EPDM rubber is dissolved, add formic acid to adjust the pH, slowly add hydrogen peroxide, stir for 6-8h, pour acetone to precipitate, wash the precipitate, and vacuum dry to obtain modified EPDM rubber; S2: Add modified EPDM rubber to xylene, mix well, introduce nitrogen, add 6-aminoquinoxaline, raise the temperature to 85-100°C, react for 6-8h, cool naturally after the reaction is completed, precipitate, wash and vacuum dry the product to obtain a high temperature resistant component.

2. The EVA hot melt adhesive for packaging according to claim 1, characterized in that: The tackifier is any one of petroleum resin, terpene resin or rosin resin.

3. The EVA hot melt adhesive for packaging according to claim 1, characterized in that: In step A, the acyl chloride modifier is any one of terephthaloyl chloride, malonyl chloride, succinyl chloride, glutaryl chloride or adipoyl chloride.

4. The EVA hot melt adhesive for packaging according to claim 1, characterized in that: In step A, the catalyst is triethylamine or pyridine.

5. The EVA hot melt adhesive for packaging according to claim 1, characterized in that: In S1, the pH is 2-3.

6. A method for preparing the EVA hot melt adhesive for packaging as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Add ethylene-vinyl acetate copolymer, tackifier and Fischer-Tropsch wax into a high-speed mixer and mix them evenly, then raise the temperature to 100-120°C for 1-3 hours, wait until the temperature drops to 80-90°C, add maleic anhydride grafted polypropylene wax, modified additives and high temperature resistant components, set the speed to 100-300r / min, stir and mix for 1-3 hours to obtain a mixed material; Step 2: Add the mixed material into a twin-screw extruder, set the inlet section temperature to 80-90°C, the middle section temperature to 110-125°C, the outlet section temperature to 90-100°C, the screw speed to 200-400r / min, melt extrude and granulate to obtain EVA hot melt adhesive.

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