Nylon honeycomb core and preparation method thereof

Abstract

The invention discloses a nylon honeycomb core and a preparation method thereof.The nylon honeycomb core comprises a plurality of nylon pipes fixedly bonded into a whole, the side wall of each nylon pipe comprises an outer protection layer, a middle layer and an inner protection layer, the equilibrium water absorption rate of the material of the inner protection layer is lower than that of the material of the middle layer, and the balance water absorption rate of the material of the inner protection layer is lower than that of the material of the middle layer. And the melting point of the material of the outer protective layer is lower than that of the material of the middle layer. Therefore, the water absorption rate of the nylon honeycomb core can be effectively reduced, so that the nylon honeycomb core has relatively high strength and modulus, can meet the requirements of high flat pressing, shearing strength and high heat resistance, can be applied to the fields of building templates, carriages of trucks, refrigerator cars and logistics vehicles, portable houses, yachts, partitions and the like, and is very wide in application.

Description

[0001] This application claims the priority of a prior application titled "A Nylon Honeycomb Core and Its Preparation Method" with the patent application number 202311608404.4, which was filed with the China National Intellectual Property Administration on November 29, 2023. Technical Field

[0002] The present invention belongs to the field of polymer materials, and specifically relates to a nylon honeycomb core and its preparation method. Background Art

[0003] The honeycomb core structure originates from nature and is a special structural form created by humans by learning from honeycombs. Since the honeycomb core mainly bears in-plane shear stress, and the in-plane stress it bears is very small compared to the upper and lower panels, when a load perpendicular to the panel is applied, the in-plane compressive stress caused by bending is mainly borne by the upper panel, and the tensile stress is borne by the lower panel. Moreover, the honeycomb core layer is much thicker than the panel, greatly increasing the span between the upper panel and the lower panel, and effectively improving its flexural stiffness.

[0004] Plastic honeycomb core materials are generally made of materials such as PVC, PP, and HDPE through extrusion, injection molding, sheet lamination, etc. As a rising star among honeycomb core materials, compared with metal honeycomb core materials, its raw material price is lower and its quality is lighter; compared with paper honeycombs, it has a greater specific strength and also has water resistance and moisture resistance that paper honeycomb core materials cannot match at all. Even if the plastic honeycomb panel is placed in water, problems such as deformation will not occur.

[0005] Nylon has attracted people's attention due to its unique low specific gravity, high tensile strength, wear resistance, good self-lubricity, excellent impact toughness, and the property of combining rigidity and flexibility, and is widely used in the automotive and transportation industries. However, there are a large number of hydroxyl groups (-OH) and amide bonds (-CONH-) in the nylon molecular structure. These functional groups can form hydrogen bonds with water molecules and are prone to water absorption. After nylon absorbs water, the changes in its mechanical properties are obvious, and the strength and modulus will drop significantly. Summary of the Invention

[0006] The present invention aims to solve one of the technical problems existing in the prior art.

[0007] In the first aspect of the present invention, a nylon honeycomb core is proposed. The nylon honeycomb core includes a plurality of nylon tubes fixedly bonded together. The side wall of the nylon tube includes an outer protective layer, an intermediate layer, and an inner protective layer. The equilibrium water absorption rate of the inner protective layer material is lower than that of the intermediate layer material, and the melting point of the outer protective layer material is lower than that of the intermediate layer material.

[0008] The test method for the equilibrium water absorption rate is "GB / T 1034-2008 Method 4: Determination of Water Absorbed in an Environment with 50% Relative Humidity".

[0009] The test method for the melting point is "GB / T 3682-2000 Determination of Melt Mass-Flow Rate and Melt Volume-Flow Rate of Thermoplastics".

[0010] In some embodiments, the equilibrium water absorption rate of the intermediate layer is ≤3%, and the equilibrium water absorption rate of the inner protective layer is ≤0.05%.

[0011] In some embodiments, the material of the inner protective layer includes at least one of PE-g-MAH, PP-g-MAH, POE-g-MAH, EPDM-g-MAH, PS-g-MAH, and EVA resin, and the grafting rate of maleic anhydride is preferably ≥0.5 wt%.

[0012] In some embodiments, the melting point of the intermediate layer is 200-310°C, and the melting point of the outer protective layer is 60-220°C.

[0013] In some embodiments, the material of the outer protective layer includes at least one of PE-g-MAH, PP-g-MAH, POE-g-MAH, EPDM-g-MAH, PS-g-MAH, and EVA resin, and the grafting rate of maleic anhydride is preferably ≥0.5 wt%.

[0014] It should be noted that the materials of the outer protective layer and the inner protective layer can be the same or different, as long as the equilibrium water absorption rate of the inner protective layer material is lower than that of the intermediate layer material, and the melting point of the outer protective layer material is lower than that of the intermediate layer material.

[0015] In some embodiments, the melt weight of the intermediate layer material is 20-80 g, preferably 25-60 g.

[0016] The test method for the melt weight is that at the processing temperature, the intermediate layer material is melt-extruded through an extruder, the rotation speed of the screw is 5-15 revolutions per minute, the melt of the intermediate layer material sags under gravity, and the maximum breaking weight of the molten strip is detected as the melt weight. The processing temperature is 10-30°C higher than the melting point of the intermediate layer material.

[0017] In some embodiments, the intermediate layer material is a polyamide resin, including bio-based polyamide PA56, bio-based polyamide PA510, bio-based polyamide PA511, bio-based polyamide PA512, bio-based polyamide PA513, bio-based polyamide PA514, bio-based polyamide PA515, bio-based polyamide PA516, bio-based polyamide PA56 / 5T, bio-based polyamide PA510 / 5T, bio-based polyamide PA511 / 5T, bio-based polyamide PA512 / 5T, bio-based polyamide PA513 / 5T, bio-based polyamide PA514 / 5T, bio-based polyamide PA515 / 5T, bio-based polyamide PA516 / 5T, bio-based polyamide PA56 / 5I, commercially available 6638, 6308, 6300, 6290, 6635, 6631, 6632, 6520, 5000, 3600, 3601, 3100, 3102, 3300, 3500, 2260, 2262, 1273, 1251, at least one of the 1320 resins.

[0018] It should be noted that is the brand of semi-bio-based or fully bio-based polyamide raw materials of Shanghai Kaisai Biotechnology Co., Ltd. The following numbers are the grades of polyamides corresponding to different performance indicators. Its main raw materials come from renewable plant-based raw materials, with a bio-based content of 25%-100%. It has the characteristics of renewable sources, recyclable products, meeting standards in performance, and competitive costs.

[0019] In some embodiments, the intermediate layer material is a modified polyamide resin, and the raw materials of the modified polyamide resin include the following components: 98.3-99.5 wt% polyamide resin, 0.2-1.2 wt% chain extender, and 0.3-0.5 wt% antioxidant. The inventors found that the chain extender has the effects of chain extension and viscosity increase on polyamide, making the molecular structure of polyamide form branching and micro-crosslinking, with a high entanglement degree and high melt strength in the molten state, so as to meet the requirements for extrusion molding of nylon tubes.

[0020] In some embodiments, the chain extender includes at least one of an epoxy chain extender, an isocyanate chain extender, and an anhydride chain extender, preferably an anhydride chain extender.

[0021] In some embodiments, the antioxidant is selected from one or more of hindered phenol antioxidants, hindered amine antioxidants, and phosphite antioxidants, preferably a combination of hindered amine antioxidants and phosphite antioxidants, and the mass ratio of the hindered amine antioxidant to the phosphite antioxidant is preferably 1:1.

[0022] In some embodiments, the thickness of the outer protective layer is 0.015 - 0.025 mm, such as 0.017 mm, 0.019 mm, 0.021 mm, 0.023 mm, 0.025 mm, etc.

[0023] In some embodiments, the thickness of the intermediate layer is 0.1 - 0.3 mm, such as 0.15 mm, 0.20 mm, 0.25 mm, etc.

[0024] In some embodiments, the thickness of the inner protective layer is 0.015 - 0.025 mm, such as 0.017 mm, 0.019 mm, 0.021 mm, 0.023 mm, 0.025 mm, etc.

[0025] In some embodiments, the cross-section of the nylon tube is at least one of circular, oval, and polygonal, and the polygon is selected from at least one of rectangle, square, rhombus, and hexagon.

[0026] In some embodiments, the maximum diameter of the cross-section of the nylon tube is 0.6 - 4.0 cm.

[0027] In some embodiments, the cross-sectional area of the nylon tube is 0.28 - 12.56 square centimeters.

[0028] In some embodiments, the height of the nylon tube is 10 - 200 mm, such as 10 mm, 30 mm, 50 mm, 70 mm, 90 mm, 110 mm, 130 mm, 150 mm, 170 mm, 190 mm, etc.

[0029] In the second aspect of the present invention, the present invention provides a method for preparing the nylon honeycomb core described in the first aspect of the present invention.

[0030] In some embodiments, the method includes:

[0031] (1) Separately feeding the intermediate layer material, the outer protective layer material, and the inner protective layer material into an extruder for material plasticization, and obtaining a nylon tube through a co-extrusion process;

[0032] (2) Lay the nylon tube, bake it into shape, cool and set it, and then slice it to obtain a nylon honeycomb core.

[0033] In some embodiments, step (1) specifically includes: separately feeding the intermediate layer material, the outer protective layer material, and the inner protective layer material into three extruders for material plasticization, extruding the plasticized materials and conveying them to their respective assigned runners, and then converging and melt-combining them in the same runner to form a three-layer structured nylon tube. It should be noted that when the inner protective layer material and the outer protective layer material used are the same, the outer protective layer material and the inner protective layer material are fed into the same extruder for material plasticization, which can reduce energy consumption and is more conducive to industrial production.

[0034] In some embodiments, in step (1), the processing temperature of the extruder is 10 - 30 °C higher than the melting points of the intermediate layer material, the outer protective layer material, and the inner protective layer material, and preferably the processing temperature of the extruder is 10 - 20 °C higher than the melting points of the intermediate layer material, the outer protective layer material, and the inner protective layer material.

[0035] In some embodiments, in step (2), the baking temperature is 5 - 20 °C higher than the melting point of the outer protective layer material, and the time is 10 - 30 min.

[0036] The nylon honeycomb core provided by the present invention has the following beneficial effects:

[0037] (1) By using materials with low water absorption and low melting points as the inner protective layer and the outer protective layer respectively, and bonding them to the inner and outer surfaces of the intermediate layer respectively, the water absorption rate of the nylon honeycomb core can be effectively reduced, so that the nylon honeycomb core has high strength and modulus, can meet the requirements of high flat compression and shear strength, and high heat resistance, and can be used in fields such as building templates, trucks, refrigerated trucks, logistics vehicle compartments, movable panel houses, yachts, partitions, etc., and has a very wide range of applications;

[0038] (2) By carrying out chain extension modification on the intermediate layer polyamide material, the chain extender has the functions of chain extension and viscosity increase for polyamide, making the polyamide molecular structure form branched chains and micro-crosslinking, with high entanglement degree and high melt strength in the molten state, so that the nylon tube meets the requirements of extrusion molding. Description of the Drawings

[0039] Figure 1 is a cross-sectional schematic view of the nylon tube in the nylon honeycomb core according to a specific embodiment of the present invention;

[0040] Figure 2 is a structural schematic view of the nylon honeycomb core according to a specific embodiment of the present invention;

[0041] Description of reference numerals: 101 - outer protective layer, 102 - intermediate layer, 103 - inner protective layer. Detailed implementation mode

[0042] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0044] PE-g-MAH (maleic anhydride grafting rate is 0.8 - 1.0 wt%) is purchased from NF530 of Mitsui Chemicals, PP-g-MAH (maleic anhydride grafting rate is 0.8 - 1.0 wt%) is purchased from QE866 of Mitsui Chemicals, POE-g-MAH (maleic anhydride grafting rate is 1.2 wt%) is purchased from AMPLIFY GR209 of Dow, EPDM-g-MAH (maleic anhydride grafting rate is 0.7% - 0.9 wt%) is purchased from KEPA1150 of Kumho Petrochemical, PS-g-MAH (maleic anhydride grafting rate is 0.5 - 0.7 wt%) is purchased from TY3351 of Dow, and EVA is purchased from 286 of Tol Chemical; 6635 6520 2260 3300, bio-based polyamide 512 / 5T resin, bio-based polyamide 56T resin are purchased from Kaisai Biology, the chain extender styrene-maleic anhydride random copolymer SAM-020 is purchased from Jia Yirong Polymer (Shanghai) Co., Ltd., the chain extender ethylene-maleic anhydride copolymer E60P is purchased from Ventrus of the United States, antioxidant 168, antioxidant 1098 and antioxidant 1010 are purchased from BASF, and antioxidant S9228 is purchased from Dover Chemical of the United States.

[0045] The bio-based polyamide 512 / 5T resin is obtained by polymerizing pentamethylenediamine, dodecanedioic acid, and terephthalic acid. The reaction ratio of pentamethylenediamine, dodecanedioic acid, and terephthalic acid is 10.2:2.9:6.9. The melting point of the bio-based polyamide PA512 / 5T resin obtained by polymerization is 302 °C, the relative viscosity is 2.43, and the moisture content is 690 ppm.

[0046] The bio-based polyamide 56T resin is obtained by polymerizing pentamethylenediamine, adipic acid, and terephthalic acid. The reaction ratio of pentamethylenediamine, adipic acid, and terephthalic acid is 10:4:6. The melting point of the bio-based polyamide PA56T resin obtained by polymerization is 282 °C, the relative viscosity is 2.7, and the moisture content is 850 ppm.

[0047] Intermediate layer material: Weigh according to the raw material formula shown in Table 1, then mix in a high-speed mixer for 3 - 5 min, and then put the mixture into a twin-screw extruder. The processing temperature is 10 - 20 °C higher than the melting point of the corresponding polyamide; draw and pelletize, and dry in a vacuum oven at 80 - 105 °C for 4 - 8 h to control the moisture content within 1000 ppm.

[0048] According to the formula shown in Table 1, modify the polyamide resins of Examples 1 - 7 and Comparative Examples 1 - 2 to obtain polyamide resin A, polyamide resin B, polyamide resin C, polyamide resin D, polyamide resin E, polyamide resin G, polyamide resin H, polyamide resin F, and polyamide resin D, and test the melt weight of the resins. (Testing method: At the processing temperature in Table 1, the modified polyamide resin is melt-extruded in an extruder. The rotation speed of the screw is 10 revolutions per minute, and the resin melt sags under gravity. Detect the maximum breaking weight of the molten strip, which is the melt weight.)

[0049] Table 1

[0050]

[0051]

[0052] Example 1

[0053] (1) Put polyamide resin A, EVA, and PE-g-MAH into the barrels of the first extruder, the second extruder, and the third extruder respectively. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, that is, a nylon tube;

[0054] Among them, the extrusion temperature of the first extruder is 265, 285, 290 °C, the extrusion temperature of the second extruder is 100, 120, 130 °C, and the extrusion temperature of the third extruder is 130, 150, 170 °C;

[0055] (2) Stack and pile up the nylon tubes, then bake them in an oven at 90 °C for 10 min, cool and shape them, and slice them to obtain a nylon honeycomb core.

[0056] Example 2

[0057] (1) Put polyamide resin B, PE-g-MAH, and ABS-g-MAH into the barrels of the first extruder, the second extruder, and the third extruder respectively. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, that is, a nylon tube;

[0058] Among them, the extrusion temperature of the first extruder is 275, 295, 310 °C, the extrusion temperature of the second extruder is 130, 160, 180 °C, and the extrusion temperature of the third extruder is 170, 195, 210 °C;

[0059] (2) Stack and pile up the nylon tubes, then bake them in an oven at 145 °C for 20 min, cool and shape them, and slice them to obtain a nylon honeycomb core.

[0060] Example 3

[0061] (1) Put polyamide resin C, PP-g-MAH, and PS-g-MAH into the barrels of the first extruder, the second extruder, and the third extruder respectively. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, that is, a nylon tube;

[0062] Among them, the extrusion temperature of the first extruder is 285, 305, 315 °C, the extrusion temperature of the second extruder is 160, 180, 190 °C, and the extrusion temperature of the third extruder is 165, 185, 200 °C;

[0063] (2) Stack and pile up the nylon tubes, then bake them in an oven at 175 °C for 30 min, cool and shape them, and slice them to obtain a nylon honeycomb core.

[0064] Example 4

[0065] (1) Put polyamide resin D, POE-g-MAH, and EPDM-g-MAH into the barrels of the first extruder, the second extruder, and the third extruder respectively. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, that is, a nylon tube;

[0066] Among them, the extrusion temperature of the first extruder is 265, 285, 290 °C, the extrusion temperature of the second extruder is 100, 150, 170 °C, and the extrusion temperature of the third extruder is 145, 170, 190 °C;

[0067] (2) Stack and pile up the nylon tubes, then bake them in an oven at 150 °C for 15 min, cool and shape them, and slice them to obtain a nylon honeycomb core.

[0068] Example 5

[0069] (1) Polyamide resin E, POE-g-MAH, and POE-g-MAH are respectively fed into the barrels of the first extruder, the second extruder, and the third extruder. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, namely a nylon tube;

[0070] Among them, the extrusion temperature of the first extruder is 195, 215, 230 °C, the extrusion temperature of the second extruder is 100, 150, 170 °C, and the extrusion temperature of the third extruder is 100, 150, 170 °C;

[0071] (2) The nylon tubes are stacked in layers, then baked in an oven at 150 °C for 15 min, cooled and shaped, and sliced to obtain a nylon honeycomb core.

[0072] Example 6

[0073] (1) Polyamide resin G, POE-g-MAH, and POE-g-MAH are respectively fed into the barrels of the first extruder, the second extruder, and the third extruder. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, namely a nylon tube;

[0074] Among them, the extrusion temperature of the first extruder is 285, 305, 315 °C, the extrusion temperature of the second extruder is 100, 150, 170 °C, and the extrusion temperature of the third extruder is 100, 150, 170 °C;

[0075] (2) The nylon tubes are stacked in layers, then baked in an oven at 150 °C for 15 min, cooled and shaped, and sliced to obtain a nylon honeycomb core.

[0076] Example 7

[0077] (1) Polyamide resin H, POE-g-MAH, and POE-g-MAH are respectively fed into the barrels of the first extruder, the second extruder, and the third extruder. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, namely a nylon tube;

[0078] Among them, the extrusion temperature of the first extruder is 285, 295, 300 °C, the extrusion temperature of the second extruder is 100, 150, 170 °C, and the extrusion temperature of the third extruder is 100, 150, 170 °C;

[0079] (2) The nylon tubes are stacked in layers, then baked in an oven at 150 °C for 15 min, cooled and shaped, and sliced to obtain a nylon honeycomb core.

[0080] Comparative Example 1

[0081] (1) Put polyamide resin F, POE-g-MAH, and EPDM-g-MAH into the barrels of the first extruder, the second extruder, and the third extruder respectively. The three raw materials are extruded simultaneously and extruded through the final die to form a three-layer co-extruded round tube, that is, a nylon tube.

[0082] Among them, the extrusion temperature of the first extruder is 265, 285, 290 °C, the extrusion temperature of the second extruder is 100, 150, 170 °C, and the extrusion temperature of the third extruder is 145, 170, 190 °C.

[0083] (2) Stack the nylon tubes in layers, then bake them in an oven at 150 °C for 15 min, cool and shape them, and slice them to obtain a nylon honeycomb core.

[0084] Comparative Example 2

[0085] (1) Put polyamide resin D and POE-g-MAH into the barrels of the first extruder and the second extruder respectively. The two raw materials are extruded simultaneously and extruded through the final die to form a two-layer co-extruded round tube, that is, a nylon tube (without an inner protective layer).

[0086] Among them, the extrusion temperature of the first extruder is 265, 285, 290 °C, and the extrusion temperature of the second extruder is 100, 150, 170 °C.

[0087] (2) Stack the nylon tubes in layers, then bake them in an oven at 150 °C for 15 min, cool and shape them, and slice them to obtain a nylon honeycomb core.

[0088] As Figure 1-2 shown, the present invention provides a nylon honeycomb core, which includes a plurality of nylon tubes fixedly bonded together. The side wall of the nylon tube includes an inner protective layer 101, an intermediate layer 102, and an outer protective layer 103. The materials and properties of the inner protective layer 101, the intermediate layer 102, and the outer protective layer 103 of the nylon honeycomb core in Examples 1-7 and Comparative Examples 1-2, as well as the cross-section, diameter, area, and height of the nylon tube are shown in Table 2.

[0089] Table 2

[0090]

[0091]

[0092] Perform the following mechanical property tests on the nylon honeycomb cores obtained in the above Examples 1-7 and Comparative Examples 1-2, and the results are shown in Table 3: The test method refers to the test method for flat compression performance of sandwich structures or cores in GB / T1453-2022, and the compression performance of the nylon honeycomb core is tested.

[0093] Table 3

[0094]

[0095] The nylon honeycomb core was placed in a thermo-hygrostat at a temperature of 23 ± 2 °C and a humidity of 50% ± 5% RH for 15 days to test its performance. By comparing Example 4 and Comparative Example 2, it was found that the middle layer and outer protective layer materials of Example 4 and Comparative Example 2 were the same. However, due to the absence of an inner protective layer in Comparative Example 2, the performance of the nylon honeycomb core decreased severely, with the compressive strength decreasing by 40% and the compressive modulus decreasing by 44.7%.

[0096] In addition, in Comparative Example 1, since the middle layer material was an unchain-extended modified polyamide resin with a low melt weight (only 14 g) and low melt strength, the nylon tube could not be formed.

[0097] The above embodiments merely illustrate the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A nylon honeycomb core, characterized in that: The nylon honeycomb core includes a plurality of nylon tubes fixedly bonded together, the side walls of the nylon tubes include an outer protective layer, an intermediate layer and an inner protective layer, the equilibrium water absorption rate of the inner protective layer material is lower than the equilibrium water absorption rate of the intermediate layer material, and the melting point of the outer protective layer material is lower than the melting point of the intermediate layer material.

2. The nylon honeycomb core according to claim 1, characterized in that: The equilibrium water absorption rate of the intermediate layer material is ≤3%, and the equilibrium water absorption rate of the inner protective layer material is ≤0.05%.

3. The nylon honeycomb core according to claim 1, characterized in that: The melting point of the intermediate layer material is 200-310°C, and the melting point of the outer protective layer material is 60-220°C.

4. The nylon honeycomb core according to claim 1, characterized in that: The melt weight of the intermediate layer material is 20 to 80 g, preferably 25 to 60 g.

5. The nylon honeycomb core according to claim 1, characterized in that: The intermediate layer material is polyamide resin, including bio-based polyamide PA56, bio-based polyamide PA510, bio-based polyamide PA511, bio-based polyamide PA512, bio-based polyamide PA513, bio-based polyamide PA514, bio-based polyamide PA515 and bio-based polyamide PA516, bio-based polyamide PA56 / 5T, bio-based polyamide PA510 / 5T, bio-based polyamide PA511 / 5T, bio-based polyamide PA512 / 5T, bio-based polyamide PA513 / 5T, bio-based polyamide PA514 / 5T, bio-based polyamide PA515 / 5T, bio-based polyamide PA516 / 5T, and bio-based polyamide PA56 / 5I.

6. The nylon honeycomb core according to claim 1, characterized in that: The intermediate layer material is commercially available At least one of the resins.

7. The nylon honeycomb core according to claim 1 or 5, characterized in that: The intermediate layer material is modified polyamide resin, and the raw materials of the modified polyamide resin include: 98.3-99.5wt% polyamide resin, 0.2-1.2wt% chain extender and 0.3-0.5wt% antioxidant.

8. The nylon honeycomb core according to claim 7, characterized in that: The chain extender comprises at least one of an epoxy chain extender, an isocyanate chain extender and an acid anhydride chain extender, preferably an acid anhydride chain extender; and / or, The antioxidant includes one or more of hindered phenol antioxidants, hindered amine antioxidants and phosphite antioxidants, preferably a combination of hindered amine antioxidants and phosphite antioxidants.

9. The nylon honeycomb core according to claim 1 or 2, characterized in that: The inner protective layer material includes at least one of PE-g-MAH, PP-g-MAH, POE-g-MAH, EPDM-g-MAH, ABS-g-MAH, PS-g-MAH, and EVA resin.

10. The nylon honeycomb core according to claim 1 or 3, characterized in that: The outer protective layer material includes at least one of PE-g-MAH, PP-g-MAH, POE-g-MAH, EPDM-g-MAH, ABS-g-MAH, PS-g-MAH, and EVA resin.

11. The nylon honeycomb core according to claim 1, characterized in that: The thickness of the outer protective layer is 0.015 to 0.025 mm; and / or, The thickness of the intermediate layer is 0.1 to 0.3 mm; and / or, The thickness of the inner protective layer is 0.015-0.025 mm.

12. The nylon honeycomb core according to claim 1, characterized in that: The cross section of the nylon tube is at least one of a circle, an ellipse, and a polygon, and the polygon is at least one of a rectangle, a square, a rhombus, and a hexagon; and / or, The maximum diameter of the cross section of the nylon tube is 0.6-4.0 cm; and / or, The cross-sectional area of ​​the nylon tube is 0.28-12.56 square centimeters; and / or, The height of the nylon tube is 10-200 mm.

13. A method for preparing the nylon honeycomb core according to any one of claims 1 to 12, characterized in that: The method comprises: (1) The middle layer material, the outer protective layer material and the inner protective layer material are respectively put into an extruder to plasticize the materials, and a nylon tube is obtained through a co-extrusion process; (2) The nylon tubes are stacked, baked, cooled and shaped, and sliced ​​to obtain a nylon honeycomb core.

14. The method according to claim 13, characterized in that In step (1), the processing temperature of the extruder is 10 to 30° C. higher than the melting points of the intermediate layer material, the outer protective layer material and the inner protective layer material; and / or, In step (2), the baking temperature is 5-20° C. higher than the melting point of the outer protective layer material, and the baking time is 10-30 minutes.

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