Adhesive material containing EVOH layer for multilayer nylon tube and preparation method of adhesive material

Abstract

The invention provides an adhesive material containing an EVOH layer for a multilayer nylon tube and a preparation method of the adhesive material, and belongs to the technical field of high polymer materials. The adhesive material comprises the following components: long carbon chain nylon resin, a compatilizer, a plasticizer, bisphenol A epoxy resin, maleic anhydride grafted EVA, an antioxidant and a lubricant. The LLDPE-g-MAH in the adhesive material provided by the invention has good flexibility and fluidity, and a polyethylene molecular chain and an anhydride group exist in the molecular structure of the LLDPE-g-MAH at the same time, so that the LLDPE-g-MAH has very good compatibility with long carbon chain nylon and EVOH. The adhesive material provided by the invention simultaneously contains the maleic anhydride grafted EVA and the bisphenol A epoxy resin, and through the common use of all the components, a very good synergistic effect is formed, the binding force of an adhesive layer is improved, the heat resistance and water resistance are improved, and the problem that a multi-layer nylon tube is unglued when being soaked in heat-resistant fuel oil is solved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, in particular to an adhesive material for a multilayer nylon tube containing an EVOH layer and a preparation method thereof. Background Art

[0002] In the early 19th century, automotive fuel pipes were made of metal pipes. Since the pipes were connected by threads, fuel leakage was prone to occur, posing a huge safety hazard. In addition, the processing method was expensive and time-consuming. Later, the metal pipes evolved into rubber pipes. There were no problems with the connection and safety of the hoses, but the hoses were relatively thick, took up a lot of space, and were not significantly lighter than metal pipes. Most importantly, the rubber refining process was toxic, which was not conducive to environmental protection and energy conservation and emission reduction. Later, it developed into the current multi-layer nylon pipes. Multi-layer nylon pipes conform to the development requirements of the automotive industry and have excellent corrosion and chemical resistance; good flexibility and wear resistance; excellent high temperature resistance and penetration protection performance; as well as good lightweight and environmental performance.

[0003] Multilayer nylon tubing primarily utilizes long-chain nylon for its excellent resistance to high and low temperatures, corrosion, chemical solvents, and zinc chloride. However, long-chain nylon is not very resistant to fuel permeation, so an additional layer of impermeability material, EVOH, is required.

[0004] EVOH (ethylene-vinyl alcohol copolymer) generally has an ethylene content of 25-45%. It is a high barrier material with excellent processing performance and gas barrier properties. The material itself has a large number of hydroxyl groups, and its barrier effect is mainly determined by the vinyl alcohol content.

[0005] EVOH offers excellent resistance to oil and organic solvents, as well as exceptional transparency, gloss, mechanical properties, elasticity, abrasion resistance, cold resistance, and surface hardness. EVOH also effectively blocks the permeation of gases such as oxygen and carbon dioxide, with gas barrier properties 100 times higher than those of PA and 1,000 times higher than those of PE and PP. EVOH, along with polyvinylidene chloride (PVDC) and polyacrylonitrile (PAN), are currently recognized as three of the world's highest barrier materials.

[0006] However, EVOH also has its drawbacks. It readily absorbs moisture, and its barrier properties degrade significantly after absorbing moisture. Therefore, in everyday use, EVOH, when used as an intermediate layer, requires adhesives to bond it to long-chain nylon. Based on the principle that like dissolves like, common components tend to bond more easily. While adhesives bonding to long-chain nylon is relatively straightforward, bonding to EVOH is more challenging. Debonding and delamination, particularly in heat-resistant fuel immersion, have long been a challenge in the materials industry. Debonding and delamination primarily occur when the adhesive separates from the EVOH layer. Improving the bonding strength between the adhesive and EVOH is key to resolving this technical challenge. Summary of the Invention

[0007] Based on this, the purpose of the present invention is to provide an adhesive material for a multilayer nylon tube containing an EVOH layer and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions: The present invention provides an adhesive material for a multilayer nylon pipe containing an EVOH layer, which comprises the following raw materials in parts by mass: 40-80 parts of long carbon chain nylon resin, Compatibilizer 5-20 parts, 5-10 parts of plasticizer, 1-5 parts of bisphenol A epoxy resin, Maleic anhydride grafted EVA 5-10 parts, 0.2-1 part antioxidant, 0.2-0.7 parts of lubricant, Long carbon chain nylon resin is a high-viscosity resin with a relative viscosity of 4-5. Long carbon chain nylon has a low melting point, low water absorption, and a certain degree of flexibility. The use of long carbon chain nylon resin can enhance the bonding strength between the adhesive material and the nylon layer in the nylon tube.

[0009] The compatibilizer is maleic anhydride grafted polyolefin, preferably linear low-density polyethylene grafted maleic anhydride (LLDPE-g-MAH). The function of LLDPE-g-MAH is to form a common bond with the EVOH layer. The ethylene structure contained in LLDPE-g-MAH has good compatibility with EVOH. In addition, considering the flexibility of the adhesive material, soft materials are generally used. LLDPE-g-MAH can achieve the above performance requirements. In addition, LLDPE-g-MAH has obvious price advantages and low cost.

[0010] Bisphenol A epoxy resins include at least one of E20, E51, E19, and NPEL-128. The molecular backbone of bisphenol A epoxy resins contains two benzene rings bridged by an isopropyl group, imparting high rigidity and thermal stability, reducing the risk of scorching and carbonization of the adhesive during extrusion. Furthermore, the molecular structure of bisphenol A epoxy resins contains ether bonds (-O-), secondary hydroxyl groups (-OH), and epoxy end groups, enhancing the interaction between the molecular chains. The high density of epoxy groups at both ends makes the reactivity significantly higher than that of typical alicyclic epoxy resins, resulting in improved processability, excellent heat resistance, and excellent fluidity.

[0011] The antioxidant includes a primary antioxidant and an auxiliary antioxidant. The primary antioxidant is at least one or more of antioxidant 245, antioxidant 1010, antioxidant 1098, and antioxidant 9228, and the auxiliary antioxidant is at least one of antioxidant 168 and antioxidant 626. The antioxidant is used to improve the antioxidant effect of the material.

[0012] The lubricant is at least one or more of PETS, OP wax, silicone, silicone oil and silicone amide, and the lubricant is used to improve the processing performance of the material.

[0013] The plasticizer includes at least one of N-butylbenzenesulfonamide, benzoate plasticizer, and plasticizer JZ-218. The plasticizer is used to improve the ductility and impact strength of the adhesive layer and reduce the risk of cracking after curing.

[0014] The present invention also provides a method for preparing the above-mentioned adhesive material, comprising the following steps: Weigh each component according to mass percentage, mix the long carbon chain nylon resin, LLDPE-g-MAH, maleic anhydride grafted EVA, and bisphenol A epoxy resin evenly, then add a lubricant and an antioxidant and mix evenly to obtain a mixture; The mixed material is added to the main feed port of a twin-screw extruder, and a plasticizer is injected from a side feed port through a liquid pump. After melting, extrusion, cooling, air drying, and pelletizing, a multi-layer nylon tube adhesive material containing an EVOH layer is obtained.

[0015] The adhesive material provided by this invention meets the requirements for automotive multilayer plastic fuel pipes ("Automotive Multilayer Plastic Fuel Pipe Standard" QC-T 798-2008) and complies with the relevant industry standard QC / T 798-2008. It is suitable for multilayer plastic fuel pipes with a normal operating temperature range of -40°C to +115°C (continuous use temperature not exceeding 90°C) and a maximum operating pressure not exceeding 0.7 MPa. The adhesive material also demonstrated excellent interlayer bonding strength after 500 hours of fuel resistance testing. Inspection of the edges of the sheared sections of the multilayer pipe after testing revealed no signs of delamination between the layers in the sheared areas.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The compatibilizer LLDPE-g-MAH in the adhesive material provided by the present invention exhibits excellent flexibility and fluidity. Its molecular structure, which contains both polyethylene chains and anhydride groups, provides excellent compatibility with both long-chain nylon and EVOH. The adhesive material provided by the present invention also contains maleic anhydride-grafted EVA and bisphenol A epoxy resin. The combined use of these components creates a synergistic effect, enhancing the bonding strength of the adhesive layer and increasing its heat and water resistance, thus resolving the issue of delamination in multilayer nylon tubing caused by heat-resistant fuel immersion.

[0017] The maleic anhydride grafted EVA used in the present invention is composed of a basic ethylene-vinyl acetate (EVA) copolymer main chain and maleic anhydride grafted side groups, wherein the EVA main chain provides flexibility, and the anhydride groups in the maleic anhydride in the side chains are strongly polar groups. The polar groups in the side chains form an amphiphilic structure with the non-polar main chain of the EVA, so that the maleic anhydride grafted EVA has both polar and non-polar properties, which can increase the binding effect between the glue components and increase the binding force with EVOH; in addition, the EVA molecular main chain of the maleic anhydride grafted EVA contains vinyl acetate (-CH2-CH(OCOCH3)-) units, wherein the acetoxy group and the anhydride groups of the maleic anhydride in the side chains are hydrogen atoms in the secondary hydroxyl groups and alkyl groups in the bisphenol A epoxy resin through hydrogen bonds, further promoting the interaction between the components. The present invention further enhances the binding force between the adhesive material and the EVOH layer by utilizing the synergistic promotion effect between the maleic anhydride grafted EVA and the bisphenol A epoxy resin.

[0018] Through innovative material and process design, this invention significantly enhances the adhesive layer's bonding strength to the nylon and EVOH layers. The extruded tube slices maintain tight interlayer adhesion and exhibit no delamination. Even after 120 hours of high-temperature immersion in fuel-resistant oil, delamination remains intact, and even peeling with force does not occur. Performance testing complies with the automotive industry standard, QC-T 798 2008, "Standard for Multilayer Plastic Fuel Pipes for Automobiles." This performance rivals that of similar materials from renowned international companies, meeting product requirements and promising prospects for widespread application. DETAILED DESCRIPTION

[0019] To facilitate understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0021] The specific information of the raw materials used in the following examples and comparative examples is as follows: The lubricant is silicone masterbatch, manufactured by Dow Corning, brand MB50-002; The main antioxidant is antioxidant 1098, produced by Tianjin Li'anlong New Materials Co., Ltd. The auxiliary antioxidant is antioxidant 168, produced by Tianjin Li'anlong New Materials Co., Ltd. The compatibilizer is LLDPE-g-MAH, manufactured by Shenyang Ketong Plastic Co., Ltd., and its brand is NJM3025. Brand NJM3025 is a refined LLDPE-g-MAH, which can avoid the formation of lumps compared to ordinary grafted materials. The present invention selects a variety of raw materials and ultimately selects this brand of material as the raw material, which can achieve optimal product performance. Maleic anhydride grafted EVA, manufactured by DuPont, USA, brand 21E533; Bisphenol A epoxy resin, manufactured by Nanya Chemical, brand E20; Plasticizer, manufactured by Suzhou Jinzhong Chemical Co., Ltd., brand JZ-218 Long carbon chain nylon resin, manufactured by Huitong Special Materials Technology Co., Ltd., brand HB-50 (PA612), relative viscosity 4.8; All materials are commercially available common products.

[0022] It is understood that the above raw materials and reagents are only examples of some specific embodiments of the present invention, which make the technical solution of the present invention clearer, and do not mean that the present invention can only adopt the above reagents, and the specific scope in the claims shall prevail. In addition, the "parts" described in the examples and comparative examples, unless otherwise specified, refer to parts by mass.

[0023] Any range described in the present invention includes the end value and any numerical value between the end values and any sub-range formed by the end value or any numerical value between the end values.

[0024] Example 1 A method for preparing an adhesive material for a multilayer nylon tube containing an EVOH layer, comprising the following steps: Weighing materials: First, dry the long carbon chain nylon resin PA612, maleic anhydride grafted EVA and bisphenol A epoxy resin E20 at 80℃ for 4 hours; then weigh the following raw materials: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 10 parts of maleic anhydride grafted EVA, 3 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 68 parts of PA612 resin; Mixing: Add weighed PA612, bisphenol A epoxy resin, compatibilizer, and maleic anhydride grafted EVA into a high-speed mixer, mix at high speed for 5 minutes, then add weighed lubricant, primary antioxidant, and auxiliary antioxidant and continue mixing at high speed for 5 minutes to obtain a mixture; Melt extrusion: the mixed material is added to the main feed of a twin-screw extruder, and the plasticizer is injected through the liquid injection port of the liquid pump. The temperature of the twin-screw extruder is 65°C from the first zone to the die head (to prevent the resin from agglomerating at the discharge port), 215°C, 235°C, 235°C, 235°C, 230°C, 230°C, 230°C, 230°C, 230°C, 230°C, and 245°C in sequence; the screw speed is 300 r / min and the feeding rate is 20 r / min.

[0025] Extrusion and pelletizing: The extruded material is cooled, air-dried, pelletized, passed through a vibrating screen, homogenized in a homogenizing tank and packaged to obtain the finished product, that is, the corresponding adhesive material.

[0026] Example 2 Compared with Example 1, the difference of this embodiment is that the amount of each raw material is different. The other processes are the same as those in Example 1. The amount of each raw material in this embodiment is as follows: 20 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 10 parts of maleic anhydride grafted EVA, 3 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 60 parts of PA612 resin.

[0027] Example 3 Compared with Example 1, the difference of this embodiment is that the amount of each raw material is different. The other processes are the same as those in Example 1. The amount of each raw material in this embodiment is as follows: 5 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 10 parts of maleic anhydride grafted EVA, 3 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 75 parts of PA612 resin.

[0028] Example 4 Compared with Example 1, the difference of this embodiment is that the amount of each raw material is different. The other processes are the same as those in Example 1. The amount of each raw material in this embodiment is as follows: 12 parts of compatibilizer, 0.2 parts of lubricant, 0.4 parts of primary antioxidant, 0.4 parts of secondary antioxidant, 5 parts of maleic anhydride grafted EVA, 5 parts of bisphenol A epoxy resin, 5 parts of plasticizer, and 72 parts of PA612 resin.

[0029] Example 5 Compared with Example 1, the difference of this embodiment is that the amount of each raw material is different. The other processes are the same as those in Example 1. The amount of each raw material in this embodiment is as follows: 12 parts of compatibilizer, 0.4 parts of lubricant, 0.3 parts of primary antioxidant, 0.3 parts of secondary antioxidant, 10 parts of maleic anhydride grafted EVA, 1 part of bisphenol A epoxy resin, 8 parts of plasticizer, and 61 parts of PA612 resin.

[0030] Comparative Example 1 Compared with Example 1, the difference in this comparative example is that the amount of each raw material is different. Other processes are the same as in Example 1. The amount of each raw material in this comparative example is as follows: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 10 parts of maleic anhydride grafted EVA, 0 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 71 parts of PA612 resin.

[0031] Comparative Example 2 Compared with Example 1, the difference in this comparative example is that the amount of each raw material is different. Other processes are the same as in Example 1. The amount of each raw material in this comparative example is as follows: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 10 parts of maleic anhydride grafted EVA, 6 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 65 parts of PA612 resin.

[0032] Comparative Example 3 Compared with Example 1, the difference in this comparative example is that the amount of each raw material is different. Other processes are the same as in Example 1. The amount of each raw material in this comparative example is as follows: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 10 parts of maleic anhydride grafted EVA, 3 parts of bisphenol A epoxy resin, 11 parts of plasticizer, and 63 parts of PA612 resin.

[0033] Comparative Example 4 Compared with Example 1, the difference in this comparative example is that the amount of each raw material is different. Other processes are the same as in Example 1. The amount of each raw material in this comparative example is as follows: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 4 parts of maleic anhydride grafted EVA, 3 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 74 parts of PA612 resin.

[0034] Comparative Example 5 Compared with Example 1, the difference in this comparative example is that the amount of each raw material is different. Other processes are the same as in Example 1. The amount of each raw material in this comparative example is as follows: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 16 parts of maleic anhydride grafted EVA, 3 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 62 parts of PA612 resin.

[0035] Comparative Example 6 Compared with Example 1, the difference in this comparative example is that the amount of each raw material is different. Other processes are the same as in Example 1. The amount of each raw material in this comparative example is as follows: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 13 parts of maleic anhydride grafted EVA, 0 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 68 parts of PA612 resin.

[0036] Comparative Example 7 Compared with Example 1, the difference in this comparative example is that the amount of each raw material is different. Other processes are the same as in Example 1. The amount of each raw material in this comparative example is as follows: 12 parts of compatibilizer, 0.6 parts of lubricant, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, 0 parts of maleic anhydride grafted EVA, 13 parts of bisphenol A epoxy resin, 6 parts of plasticizer, and 68 parts of PA612 resin.

[0037] The materials prepared in each example and comparative example were subjected to performance and application testing. The application test involved a tube extrusion test (the tube consisted of a five-layer nylon tube consisting, from the inside out, of a PA612 layer, an adhesive layer, an EVOH layer, an adhesive layer, and a PA12 layer. The layer thicknesses were 0.2 mm, 0.1 mm, 0.15 mm, 0.1 mm, and 0.45 mm, respectively). Due to insufficient liquid pump capacity and unstable injection volume, some of the materials prepared in the comparative examples exhibited poor fluidity and could not be extruded, resulting in the inability to manufacture products. Therefore, some tests could not be conducted, resulting in no data. The performance test methods and conditions are shown in Table 1; the test results are shown in Tables 2 and 3. Table 1

[0038] Table 2

[0039] Note: NB in the table means that the impact spline exceeded the measurement range during the test but did not break; the same applies to Table 3.

[0040] Table 3

[0041] Note: Due to the change in the dosage relationship between the raw materials, the production of Comparative Examples 2 and 5 failed and no product was output, so there is no relevant test data.

[0042] The test results in the table above show that the materials prepared in Examples 1 to 5 can be extruded smoothly, have good mechanical properties, a flexural modulus of less than 600 MPa, and good flexibility, making them suitable for extruded pipes. The extrusion process is smooth, the pipe wall is smooth, and cross-section observation of the pipe shows tight interlayer adhesion. A fuel oil immersion test at 60°C for 120 hours shows no separation between the layers, and no separation occurs when forcibly peeled with tweezers. The test results of Examples 1-5 show that when the maleic anhydride grafted EVA content is between 5-10%, it can provide excellent auxiliary bonding effect. When the amount of maleic anhydride grafted EVA and bisphenol A epoxy resin is within the upper and lower limits of the reasonable range, the test results show that the bonding effect is still good.

[0043] The test results of Comparative Example 1 show that, in the absence of bisphenol A epoxy resin, the interlayer adhesion of the obtained product is insufficient, and some delamination occurs between the two layers during the oil-fuel immersion process.

[0044] The test results of Comparative Example 2 show that when the amount of bisphenol A epoxy resin is high, the active groups such as epoxy in it have a strong chain extension effect, which causes adhesion to the metal wall of the extruder, reduces fluidity, and causes degradation during the residence time in the machine.

[0045] The results of Comparative Example 3 show that when the plasticizer dosage is high, reaching 11 parts, the plasticizer precipitates due to heat during the tube extrusion process, forming an oil film at the interface layer. The adhesive layer and the EVOH layer have poor adhesion, and the two layers easily separate during the fuel immersion test. The results of Comparative Example 4 show that when the amount of maleic anhydride grafted EVA is low, the interlayer structure bonding is not strong, and separation occurs in the subsequent related fuel oil immersion test, which does not meet the product requirements; The results of Comparative Example 5 show that when the amount of maleic anhydride grafted EVA is too high, a certain cross-linking effect occurs, resulting in reduced fluidity, affecting the intermixing effect of the adhesive layer and the polyamide layer, and the bonding force is not strong. Crystal points and small bumps are generated during the tube extrusion process, affecting the bonding effect and appearance. In the subsequent related fuel oil immersion test, separation occurs, and the product requirements are not met. The results of Comparative Example 6 show that when bisphenol A epoxy resin is not added and all parts of bisphenol A epoxy resin are replaced by maleic anhydride grafted EVA, there is no abnormality in the production process. However, due to limited bonding strength, after heat-resistant fuel, the cross-section is cut and observed to separate the adhesive layer and the nylon layer. The results of Comparative Example 7 show that when no maleic anhydride grafted EVA is added and all the maleic anhydride grafted EVA is replaced by bisphenol A epoxy resin, there is no abnormality in the production process. However, due to limited bonding strength, after hot fuel resistance, the cross-section is cut and observed to separate the glue layer and the EVOH layer. The results of Comparative Examples 6 and 7 show that maleic anhydride-grafted EVA and bisphenol A epoxy resin have a synergistic effect. Although a single component would not pass the hot fuel oil immersion test, the combination of maleic anhydride-grafted EVA and bisphenol A epoxy resin can improve the bonding performance of the adhesive, allowing it to pass the hot fuel oil immersion test when used in nylon tubes.

[0046] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0047] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent modifications made according to the scope of the claims of the present application are within the scope of protection of the claims of the present application.

Claims

1. An adhesive material for a multilayer nylon tube containing an EVOH layer, characterized in that: The adhesive material includes the following raw materials in parts by mass: 40-80 parts of long carbon chain nylon resin, Compatibilizer 5-20 parts, 5-10 parts of plasticizer, 1-5 parts of bisphenol A epoxy resin, Maleic anhydride grafted EVA 5-10 parts, 0.2-1 part antioxidant, Lubricant 0.2-0.7 parts.

2. The adhesive material for multi-layer nylon pipes containing an EVOH layer according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted polyolefin.

3. The adhesive material for multi-layer nylon pipes containing an EVOH layer according to claim 1, characterized in that: The bisphenol A epoxy resin is at least one of E20, E51, E19, and NPEL-128.

4. The adhesive material for multi-layer nylon pipes containing an EVOH layer according to claim 1, characterized in that: The plasticizer is at least one of N-butylbenzenesulfonamide, benzoate plasticizer, and JZ-218.

5. The adhesive material for multi-layer nylon pipes containing an EVOH layer according to claim 1, characterized in that: The relative viscosity of the long carbon chain nylon resin is 4-5.

6. The adhesive material for multi-layer nylon tubes containing an EVOH layer according to claim 1, characterized in that: The antioxidant includes a primary antioxidant and an auxiliary antioxidant.

7. The adhesive material for multi-layer nylon pipes containing an EVOH layer according to claim 6, characterized in that: The main antioxidant is at least one of antioxidant 245, antioxidant 1010, antioxidant 1098, and antioxidant 9228.

8. The adhesive material for multi-layer nylon pipes containing an EVOH layer according to claim 6, characterized in that: The auxiliary antioxidant is at least one of antioxidant 168 and antioxidant 626.

9. The adhesive material for multi-layer nylon pipes containing an EVOH layer according to claim 1, characterized in that: The lubricant is at least one of PETS, OP wax, silicone, silicone oil, and silicone amide.

10. The method for preparing an adhesive material for a multi-layer nylon tube containing an EVOH layer according to any one of claims 1 to 9, wherein: The following steps are involved: After uniformly mixing long carbon chain nylon resin, LLDPE-g-MAH, maleic anhydride grafted EVA, and bisphenol A epoxy resin, lubricant and antioxidant are added and mixed uniformly to obtain a mixture; The mixed material is added to the main feeding port of the twin-screw extruder, and the plasticizer is injected from the side feeding port through a liquid pump. After melting, extrusion, cooling, air drying and pelletizing, the adhesive material is obtained.

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