Flame-retardant aluminum honeycomb panel and preparation method thereof

Abstract

The present invention discloses a flame-retardant aluminum honeycomb panel in the field of building materials technology and a preparation method thereof. The flame-retardant aluminum honeycomb panel comprises the following components: a flame-retardant coating, an upper aluminum plate, a lower aluminum plate, an aluminum honeycomb core, and an adhesive. The flame-retardant coating comprises the following components by weight: 80-100 parts of epoxy resin, 20-30 parts of a curing agent, 30-40 parts of butyl acetate, and 8-15 parts of a flame-retardant additive. The flame-retardant additive is prepared by coating graphite-phase carbon nitride nanosheets with ammonium polyphosphate and then with melamine-formaldehyde resin. The flame-retardant additive is added to the epoxy resin coating to improve the flame-retardant and heat-insulating properties of the coating. The flame-retardant additive is then applied to the outer surface of the aluminum honeycomb panel to produce an aluminum honeycomb panel with excellent flame retardancy.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and specifically relates to a flame-retardant aluminum honeycomb panel and a preparation method thereof. Background Art

[0002] Honeycomb panel is a composite panel with a "sandwich" structure, consisting of upper and lower panels and a middle honeycomb core layer. It has the characteristics of high flatness, high specific strength, good specific stiffness, low density, and high energy absorption. At present, honeycomb panels can be mainly divided into several categories according to their manufacturing materials, such as metal honeycomb panels, paper honeycomb panels, wooden honeycomb panels and fiberglass honeycomb panels. Among them, aluminum honeycomb panels have higher strength than other materials and have been widely used in architectural decoration, aerospace and other fields. The two side panels of the aluminum honeycomb panel are high-strength aluminum panels, and the middle core panel is a special hexagonal aluminum honeycomb. The aluminum panel and the honeycomb core are connected by bonding, which has the advantages of light weight, high strength and good stability.

[0003] At present, the flame retardant and heat-insulating properties of aluminum honeycomb panels are insufficient, especially when used as kitchen wall panels, the flame retardant effect is not ideal. Once a fire occurs, there are certain safety hazards, and the performance needs to be further improved. Summary of the Invention

[0004] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a flame-retardant aluminum honeycomb panel and a preparation method thereof. A flame-retardant additive is prepared by coating ammonium polyphosphate with graphite phase carbon nitride nanosheets and then coating them with melamine formaldehyde resin. The flame-retardant additive is added to the epoxy resin coating to improve the flame-retardant and heat-insulating effect of the coating. The flame-retardant additive is then coated on the outside of the aluminum honeycomb panel to obtain an aluminum honeycomb panel with good flame-retardant effect.

[0005] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is as follows: the present invention proposes a flame-retardant aluminum honeycomb panel and a preparation method thereof, wherein the flame-retardant aluminum honeycomb panel comprises the following components: a flame-retardant coating, an upper aluminum plate, a lower aluminum plate, an aluminum honeycomb core, and an adhesive; the flame-retardant coating comprises the following components in parts by weight: 80-100 parts of epoxy resin, 20-30 parts of curing agent, 30-40 parts of butyl acetate, and 8-15 parts of a flame retardant additive.

[0006] Furthermore, the upper aluminum plate and the lower aluminum plate are 3003 alloy aluminum plates with a thickness of 0.8-1.5 mm.

[0007] 3003 alloy is an Al-Mn alloy. In addition to Al, it mainly contains Mn as an alloying element. It has good plasticity, weldability and corrosion resistance.

[0008] Furthermore, the aluminum honeycomb core is a 3003 aluminum honeycomb core with hexagonal channels, the thickness of the hexagonal channels is 0.1-0.2 mm, the side length is 5-6 mm, and the thickness of the aluminum honeycomb core is 15-30 mm.

[0009] Furthermore, the adhesive is a two-component polyurethane adhesive.

[0010] Since polyurethane contains urethane bonds in its molecules, it can form good hydrogen bonding forces with the metal substrate. Therefore, it has high adhesion on the metal substrate and can firmly bond the upper aluminum plate, aluminum honeycomb core and lower aluminum plate together.

[0011] Furthermore, the preparation method of the flame retardant additive comprises the following steps:

[0012] S1, take 20-30g of urea and put it into a crucible, place it in a tube furnace and heat it to 550-570℃ and calcine it for 2-3h, cool it to room temperature and take it out to obtain powder, take 3-5g of powder and put it into a crucible, place it in a tube furnace and heat it to 500-520℃ and calcine it for 2-3h, cool it and take it out, wash it with deionized water 3 times, and dry it at 60℃ for 10-12h to obtain graphite phase carbon nitride nanosheets;

[0013] S2. The graphite carbon nitride nanosheets obtained in step S1 were dispersed in 200 mL of isopropanol to obtain a dispersion, subjected to ultrasonic treatment, and ammonium polyphosphate was added. The dispersion was heated to 100° C. and kept warm for 15-20 h. The precipitate was filtered and washed three times with anhydrous ethanol, and dried at 80° C. for 10-12 h to obtain a graphite carbon nitride nanosheet / ammonium polyphosphate dispersion.

[0014] S3, taking 12-14g of melamine and adding it to 30mL of formaldehyde solution, adjusting the pH value to 8, and stirring the reaction at 80°C for 1-2h to obtain melamine formaldehyde resin;

[0015] S4. Take the melamine formaldehyde resin obtained in step (3) and the graphite phase carbon nitride nanosheets / ammonium polyphosphate obtained in step S2, add them to 200 mL of ethanol, adjust the pH value to 5, and stir the reaction at 80° C. for 2-3 hours to obtain a flame retardant additive.

[0016] Furthermore, in step S2, the mass concentration of the graphite-phase carbon nitride nanosheets in the dispersion is 5-15 g / L.

[0017] Furthermore, in step S2, the mass ratio of the graphite phase carbon nitride nanosheets to ammonium polyphosphate is 1-3:8.

[0018] Furthermore, in step S2, the ultrasonic treatment time is 2-3 hours and the power is 400W.

[0019] Furthermore, in step S3, the mass fraction of the formaldehyde solution is 36%.

[0020] Furthermore, in step S4, the mass ratio of the melamine formaldehyde resin to the graphite phase carbon nitride nanosheets / ammonium polyphosphate is 1:2-3.

[0021] The present invention provides a method for preparing a flame-retardant aluminum honeycomb panel, which specifically comprises the following steps:

[0022] Add flame retardant additive to butyl acetate and stir evenly, then add epoxy resin and curing agent, stir thoroughly, and evenly apply to the outer sides of the upper and lower aluminum plates with a thickness of 1 mm. Dry at room temperature for 24 hours, and use adhesive to bond the upper aluminum plate, aluminum honeycomb core and lower aluminum plate in turn. After curing, a flame retardant aluminum honeycomb panel is obtained.

[0023] The beneficial effects achieved by the present invention are as follows:

[0024] The invention prepares a flame retardant additive by coating ammonium polyphosphate with graphite phase carbon nitride nanosheets and then coating it with melamine formaldehyde resin, and then adding the flame retardant additive to the epoxy resin coating to improve the flame retardant and heat insulation effect of the coating. The flame retardant additive is coated on the outer side of the aluminum honeycomb panel to obtain an aluminum honeycomb panel with good flame retardant effect. The epoxy resin coating has good corrosion resistance and weather resistance, can protect the aluminum honeycomb panel, and improve the service life. The ammonium polyphosphate will decompose into polyphosphoric acid, metaphosphoric acid and other phosphoric acid derivatives when heated. These phosphoric acid derivatives have the function of catalyzing the cross-linking of polymers into carbon. The graphite phase carbon nitride nanosheets are used as the flame retardant additives for ammonium polyphosphate and melamine formaldehyde resin. The good thermal conductivity of the intermediate layer of melamine formaldehyde resin can promote the faster decomposition of ammonium polyphosphate, prompting the decomposition products of ammonium polyphosphate and melamine formaldehyde resin to cross-link to form a denser carbon layer. At the same time, the high thermal stability and high surface area of ​​the graphite phase carbon nitride nanosheets can isolate the oxygen, heat and smoke in the combustion, thereby achieving the effect of flame retardancy and heat insulation; and, by coating the graphite phase carbon nitride nanosheet / ammonium polyphosphate composite material with melamine formaldehyde resin, its compatibility with the epoxy resin matrix can be improved, so that it is evenly distributed in the matrix, achieving better flame retardancy. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Graph showing the thermal stability test results of the flame-retardant aluminum honeycomb panels prepared in Examples 1-3 of the present invention and Comparative Example 1;

[0026] Figure 2 This is a scanning electron microscope image of the flame retardant additive prepared in Example 1 of the present invention;

[0027] Figure 3 This is a schematic structural diagram of the aluminum honeycomb panel proposed in the present invention.

[0028] Explanation of the numbers: 1. Flame retardant coating, 2. Upper aluminum plate, 3. Aluminum honeycomb core, 4. Lower aluminum plate.

[0029] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only 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 ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods and materials similar or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only and are not intended to limit the scope of this application.

[0032] The experimental methods in the following examples are conventional methods unless otherwise specified; the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0033] Some of the materials in the examples are derived from the following sources:

[0034] Epoxy resin, product number E-51, was purchased from Wanqing Chemical Technology Co., Ltd.;

[0035] Curing agent, product number Y-3313, was purchased from Dongguan Yuanbang Electronic Materials Co., Ltd.

[0036] Example 1

[0037] A flame-retardant aluminum honeycomb panel and a preparation method thereof. The flame-retardant aluminum honeycomb panel comprises the following components: a flame-retardant coating, an upper aluminum plate, a lower aluminum plate, an aluminum honeycomb core, and an adhesive; the flame-retardant coating comprises the following components in parts by weight: 80 parts of epoxy resin, 20 parts of curing agent, 30 parts of butyl acetate, and 8 parts of a flame-retardant additive.

[0038] The upper and lower aluminum plates are 3003 alloy aluminum plates with a thickness of 0.8 mm.

[0039] The aluminum honeycomb core is a 3003 aluminum honeycomb core with hexagonal channels. The thickness of the hexagonal channels is 0.1 mm, the side length is 5 mm, and the thickness of the aluminum honeycomb core is 15 mm.

[0040] The adhesive is a two-component polyurethane adhesive.

[0041] The preparation method of the flame retardant additive comprises the following steps:

[0042] S1. Take 20g of urea and put it into a crucible. Place it in a tube furnace and heat it to 550℃ and calcine it for 2h. After cooling to room temperature, take it out to obtain powder. Take 3g of powder and put it into a crucible. Place it in a tube furnace and heat it to 500℃ and calcine it for 2h. After cooling, take it out, wash it with deionized water 3 times, and dry it at 60℃ for 10h to obtain graphite phase carbon nitride nanosheets.

[0043] S2. Disperse 1 g of the graphite-phase carbon nitride nanosheets obtained in step S1 in 200 mL of isopropanol and ultrasonicate for 2 h at a power of 400 W. Add 8 g of ammonium polyphosphate and heat to 100° C. for 15 h. Filter the precipitate, wash it three times with anhydrous ethanol, and dry it at 80° C. for 10 h to obtain graphite-phase carbon nitride nanosheets / ammonium polyphosphate.

[0044] S3, taking 12g of melamine and adding it to 30mL of formaldehyde solution, the mass fraction of the formaldehyde solution is 36%, adjusting the pH value to 8, and stirring the reaction at 80°C for 1h to obtain melamine formaldehyde resin;

[0045] S4. Take 1 g of the melamine formaldehyde resin obtained in step (3) and 2 g of the graphite phase carbon nitride nanosheets / ammonium polyphosphate obtained in step S2, add them to 200 mL of ethanol, adjust the pH value to 5, and stir the reaction at 80°C for 2 h to obtain a flame retardant additive.

[0046] This embodiment provides a method for preparing a flame-retardant aluminum honeycomb panel, which specifically includes the following steps:

[0047] Add flame retardant additive to butyl acetate and stir evenly, then add epoxy resin and curing agent, stir thoroughly, and evenly apply to the outer sides of the upper and lower aluminum plates with a thickness of 1 mm. Dry at room temperature for 24 hours, and use adhesive to bond the upper aluminum plate, aluminum honeycomb core and lower aluminum plate in turn. After curing, a flame retardant aluminum honeycomb panel is obtained.

[0048] Example 2

[0049] A flame-retardant aluminum honeycomb panel and a preparation method thereof. The flame-retardant aluminum honeycomb panel comprises the following components: a flame-retardant coating, an upper aluminum plate, a lower aluminum plate, an aluminum honeycomb core, and an adhesive; the flame-retardant coating comprises the following components in parts by weight: 100 parts of epoxy resin, 30 parts of curing agent, 40 parts of butyl acetate, and 15 parts of a flame-retardant additive.

[0050] The upper and lower aluminum plates are 3003 alloy aluminum plates with a thickness of 1.5 mm.

[0051] The aluminum honeycomb core is a 3003 aluminum honeycomb core with hexagonal channels. The thickness of the hexagonal channels is 0.2 mm, the side length is 6 mm, and the thickness of the aluminum honeycomb core is 30 mm.

[0052] The adhesive is a two-component polyurethane adhesive.

[0053] The preparation method of the flame retardant additive comprises the following steps:

[0054] S1, take 30g of urea and put it into a crucible, place it in a tube furnace and heat it to 570℃ and calcine for 3h, cool it to room temperature and take it out to obtain powder, take 5g of powder and put it into a crucible, place it in a tube furnace and heat it to 520℃ and calcine for 3h, cool it and take it out, wash it with deionized water 3 times, and dry it at 60℃ for 12h to obtain graphite phase carbon nitride nanosheets;

[0055] S2. 3 g of the graphite carbon nitride nanosheets obtained in step S1 were dispersed in 200 mL of isopropanol and sonicated for 3 h at 400 W. 8 g of ammonium polyphosphate was added and the mixture was heated to 100° C. and kept warm for 20 h. The precipitate was filtered and washed three times with anhydrous ethanol. The precipitate was dried at 80° C. for 12 h to obtain a graphite carbon nitride nanosheet / ammonium polyphosphate mixture.

[0056] S3. Take 14 g of melamine and add it to 30 mL of formaldehyde solution (mass fraction of formaldehyde solution is 36%). Adjust the pH value to 8 and stir the mixture at 80°C for 2 h to obtain melamine formaldehyde resin.

[0057] S4. Take 1 g of the melamine formaldehyde resin obtained in step (3) and 3 g of the graphite phase carbon nitride nanosheets / ammonium polyphosphate obtained in step S2, add them to 200 mL of ethanol, adjust the pH value to 5, and stir the reaction at 80°C for 3 hours to obtain a flame retardant additive.

[0058] This embodiment provides a method for preparing a flame-retardant aluminum honeycomb panel, and the preparation method is carried out with reference to Example 1.

[0059] Example 3

[0060] A flame-retardant aluminum honeycomb panel and a preparation method thereof. The flame-retardant aluminum honeycomb panel comprises the following components: a flame-retardant coating, an upper aluminum plate, a lower aluminum plate, an aluminum honeycomb core, and an adhesive; the flame-retardant coating comprises the following components in parts by weight: 90 parts of epoxy resin, 25 parts of curing agent, 35 parts of butyl acetate, and 11 parts of a flame-retardant additive.

[0061] The upper and lower aluminum plates are 3003 alloy aluminum plates with a thickness of 1.1 mm.

[0062] The aluminum honeycomb core is a 3003 aluminum honeycomb core with hexagonal channels. The thickness of the hexagonal channels is 0.15 mm, the side length is 6 mm, and the thickness of the aluminum honeycomb core is 20 mm.

[0063] The adhesive is a two-component polyurethane adhesive.

[0064] The preparation method of the flame retardant additive comprises the following steps:

[0065] S1, take 25g of urea and put it into a crucible, place it in a tube furnace and heat it to 560℃ and calcine it for 2.5h, cool it to room temperature and take it out to obtain powder, take 4g of powder and put it into a crucible, place it in a tube furnace and heat it to 510℃ and calcine it for 2.5h, cool it and take it out, wash it with deionized water 3 times, and dry it at 60℃ for 11h to obtain graphite phase carbon nitride nanosheets;

[0066] S2. Disperse 2 g of the graphite carbon nitride nanosheets obtained in step S1 in 200 mL of isopropanol and ultrasonicate for 2.5 h at a power of 400 W. Add 8 g of ammonium polyphosphate and heat to 100° C. for 17 h. Filter the precipitate, wash it three times with anhydrous ethanol, and dry it at 80° C. for 11 h to obtain graphite carbon nitride nanosheets / ammonium polyphosphate.

[0067] S3. Take 13 g of melamine and add it to 30 mL of formaldehyde solution (mass fraction of formaldehyde solution is 36%). Adjust the pH value to 8 and stir the mixture at 80°C for 1.5 h to obtain melamine formaldehyde resin.

[0068] S4. Take 1 g of the melamine formaldehyde resin obtained in step (3) and 2.5 g of the graphite phase carbon nitride nanosheets / ammonium polyphosphate obtained in step S2, add them to 200 mL of ethanol, adjust the pH value to 5, and stir the reaction at 80°C for 2.5 hours to obtain a flame retardant additive.

[0069] This embodiment provides a method for preparing a flame-retardant aluminum honeycomb panel, and the preparation method is carried out with reference to Example 1.

[0070] Comparative Example 1

[0071] This comparative example provides a flame-retardant aluminum honeycomb panel and a preparation method thereof. The difference between the comparative example and Example 1 is that the flame-retardant coating does not contain a flame-retardant additive, and the remaining components and component contents are the same as those in Example 1.

[0072] Experimental example

[0073] 1. The flame retardant aluminum honeycomb panels prepared in Examples 1-3 and Comparative Example 1 of the present invention were subjected to a combustion performance test. The specific method was based on the standard GB / T 8624-2012 "Classification of Combustion Performance of Building Materials and Products".

[0074] 2. The flame-retardant aluminum honeycomb panels prepared in Examples 1-3 of the present invention and Comparative Example 1 were subjected to a thermal stability test. The specific method is as follows: a thermogravimetric analyzer was used to test the flame-retardant aluminum honeycomb panels. The samples were heated from 20°C to 700°C at a heating rate of 20°C / min under a nitrogen atmosphere, and the weight residual rate was measured:

[0075] Weight residual rate = (weight after the experiment / weight before the experiment) × 100%.

[0076] 3. The surface morphology of the flame retardant additive prepared in Example 1 was observed using a scanning electron microscope.

[0077] Result Analysis

[0078] Table 1

[0079]

[0080] Table 1 shows the combustion performance test results of the flame retardant aluminum honeycomb panels prepared in Examples 1-3 of the present invention and Comparative Example 1. It can be seen that Example 1 has better flame retardant performance than Comparative Example 1.

[0081] Figure 1 The thermal stability test results of the flame-retardant aluminum honeycomb panels prepared in Examples 1-3 of the present invention and Comparative Example 1 are shown. As shown in the figure, the weight residual rates of Examples 1-3 are 81.3%, 80.7%, and 81.9%, and the weight residual rate of Comparative Example 1 is 68.2%. The weight residual rate of Example 1 is increased by 13.1% compared with Comparative Example 1. This is because the ammonium polyphosphate in the flame retardant additive decomposes into polyphosphoric acid, metaphosphoric acid and other phosphoric acid derivatives when heated. These phosphoric acid derivatives have the function of catalyzing the cross-linking of polymers into carbon. The graphite phase carbon nitride nanosheets serve as the intermediate layer between ammonium polyphosphate and melamine formaldehyde resin. Their good thermal conductivity can promote faster decomposition of ammonium polyphosphate, and promote the cross-linking of the decomposition products of ammonium polyphosphate and melamine formaldehyde resin to form a denser carbon layer. Therefore, the residual carbon rate of Example 1 is higher.

[0082] Figure 2 This is a scanning electron microscope image of the flame retardant additive prepared in Example 1 of the present invention.

[0083] Figure 3 This is a schematic structural diagram of the aluminum honeycomb panel proposed in the present invention.

[0084] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

[0085] The present invention and its embodiments are described above. Such description is not restrictive. The drawings show only one embodiment of the present invention, and actual applications are not limited thereto. In short, if a person skilled in the art is inspired by the above, and does not deviate from the purpose of the present invention, any method and embodiment similar to the technical solution without creative design shall fall within the scope of protection of the present invention.

Claims

1. A flame-retardant aluminum honeycomb panel, characterized by: The invention comprises the following components: a flame retardant coating, an upper aluminum plate, a lower aluminum plate, an aluminum honeycomb core, and an adhesive; the flame retardant coating comprises the following components in parts by weight: 80-100 parts of epoxy resin, 20-30 parts of curing agent, 30-40 parts of butyl acetate, and 8-15 parts of flame retardant additive; The preparation method of the flame retardant additive comprises the following steps: S1, take 20-30g of urea and put it into a crucible, place it in a tube furnace and heat it to 550-570℃ and calcine it for 2-3h, cool it to room temperature and take it out to obtain powder, take 3-5g of powder and put it into a crucible, place it in a tube furnace and heat it to 500-520℃ and calcine it for 2-3h, cool it and take it out, wash it with deionized water 3 times, and dry it at 60℃ for 10-12h to obtain graphite phase carbon nitride nanosheets; S2. The graphite carbon nitride nanosheets obtained in step S1 were dispersed in 200 mL of isopropanol to obtain a dispersion, subjected to ultrasonic treatment, and ammonium polyphosphate was added. The dispersion was heated to 100° C. and kept warm for 15-20 h. The precipitate was filtered and washed three times with anhydrous ethanol, and dried at 80° C. for 10-12 h to obtain a graphite carbon nitride nanosheet / ammonium polyphosphate dispersion. S3, taking 12-14g of melamine and adding it to 30mL of formaldehyde solution, adjusting the pH value to 8, and stirring the reaction at 80°C for 1-2h to obtain melamine formaldehyde resin; S4, taking the melamine formaldehyde resin obtained in step (3) and the graphite phase carbon nitride nanosheets / ammonium polyphosphate obtained in step S2, adding them to 200 mL of ethanol, adjusting the pH value to 5, and stirring the reaction at 80°C for 2-3 hours to obtain a flame retardant additive; In step S2, the mass ratio of the graphite phase carbon nitride nanosheets to ammonium polyphosphate is 1-3:8; In step S4, the mass ratio of the melamine formaldehyde resin to the graphite phase carbon nitride nanosheets / ammonium polyphosphate is 1:2-3; The method for preparing the flame-retardant aluminum honeycomb panel specifically comprises the following steps: adding a flame-retardant additive to butyl acetate and stirring evenly, then adding epoxy resin and a curing agent, stirring thoroughly, and evenly applying the mixture to the outer sides of an upper aluminum plate and a lower aluminum plate to a thickness of 1 mm, drying the mixture at room temperature for 24 hours, and sequentially bonding the upper aluminum plate, the aluminum honeycomb core, and the lower aluminum plate with an adhesive, and curing the mixture to obtain the flame-retardant aluminum honeycomb panel.

2. The flame-retardant aluminum honeycomb panel according to claim 1, characterized in that: In step S2, the ultrasonic treatment time is 2-3 hours and the power is 400W.

3. The flame-retardant aluminum honeycomb panel according to claim 2, characterized in that: In step S3, the mass fraction of the formaldehyde solution is 36%.

4. The flame-retardant aluminum honeycomb panel according to claim 3, characterized in that: The upper aluminum plate and the lower aluminum plate are 3003 alloy aluminum plates with a thickness of 0.8-1.5 mm.

5. The flame-retardant aluminum honeycomb panel according to claim 4, characterized in that: The aluminum honeycomb core is a 3003 aluminum honeycomb core with hexagonal channels. The thickness of the hexagonal channels is 0.1-0.2 mm, the side length is 5-6 mm, and the thickness of the aluminum honeycomb core is 15-30 mm.

6. The flame-retardant aluminum honeycomb panel according to claim 5, characterized in that: The adhesive is a two-component polyurethane adhesive.

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