A core material for a class a fireproof metal composite plate and a preparation method thereof

Abstract

The application relates to the technical field of building materials, in particular to a core material for A-grade fireproof metal composite board and a preparation method thereof. According to weight parts, the core material for the A-grade fireproof metal composite board comprises the following raw materials: 30-60 parts of base resin, 20-40 parts of flame retardant, 5-10 parts of modified montmorillonite, 0.5-2 parts of coupling agent, 0.5-3 parts of dispersant, 1-3 parts of compatibility agent and 0.5-3 parts of lubricant. The core material has excellent flame retardancy, antibacterial property and mechanical property.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, specifically to a core material for Class A fire-resistant metal composite panels and its preparation method. Background Technology

[0002] Metal composite panels typically consist of two layers of metal sheets and a core material layer in between. They offer advantages such as economy, diverse colors, convenient construction, and excellent processing performance, making them widely used in large industrial plants, warehouses, stadiums, and exhibition halls. Currently, most mainstream metal composite panel products on the market meet the Class B fire resistance standard. However, with the increasing emphasis on fire safety by the government and the growing public awareness of fire prevention, the market's requirements for the fire resistance performance of building materials are becoming increasingly stringent. Class A fire-resistant metal composite panels significantly outperform Class B fire-resistant aluminum composite panels in key fire resistance indicators such as flame retardancy, smoke emission, and heat release, and have become an important development direction in this field.

[0003] Currently, most fire-resistant core materials on the market use polyolefins or their copolymers as the base material. These materials are flammable and release a large amount of heat when burning, making it difficult to meet the requirements of Class A fire-resistant metal composite panels. Furthermore, the core material inside metal composite panels is often pressed together in plate form. When one part of the core material is exposed to moisture, the moisture diffuses to the surrounding core material, thus affecting the overall durability and service life of the core material. Therefore, it is necessary to improve existing technologies to solve these problems. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the first objective of the present invention is to provide a core material for Class A fire-resistant metal composite panels, which has excellent flame retardant properties, antibacterial properties, mechanical properties and durability.

[0005] The second objective of this invention is to provide a method for preparing the core material for Class A fire-resistant metal composite panels, which is simple in process.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A core material for a Class A fire-resistant metal composite panel, comprising the following raw materials by weight: 30-60 parts of matrix resin, 20-40 parts of flame retardant, 5-10 parts of modified montmorillonite, 0.5-2 parts of coupling agent, 0.5-3 parts of dispersant, 1-3 parts of compatibilizer, and 0.5-3 parts of lubricant.

[0008] The preparation process of the modified montmorillonite is as follows:

[0009] (1) Add the pretreated montmorillonite to dichloromethane, then add azide-diethylene glycol-bromine and triethylamine, reflux the reaction, filter, wash and dry after the reaction is complete to obtain azide-modified montmorillonite;

[0010] (2) Add the azido-modified montmorillonite to N,N-dimethylformamide, then add 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne, then add copper sulfate solution and sodium ascorbate, and react under inert gas protection. After the reaction is completed, filter, wash and dry to obtain the modified montmorillonite.

[0011] This invention first pre-treats montmorillonite with 3-aminopropyltriethoxysilane through surface amination; then, it introduces azide groups through a nucleophilic substitution reaction of amino groups with azido-diethylene glycol-bromine; finally, it grafts 4,4,5,5,6,6,6-heptafluoro-3,3-bis(trifluoromethyl)-1-hexyne onto the surface of montmorillonite through an azdo-alkynyl click chemistry reaction, thus obtaining the above-mentioned modified montmorillonite.

[0012] Furthermore, in step (1), the mass ratio of pretreated montmorillonite, azide-diethylene glycol-bromine, and triethylamine is 5:(1.8-3.6):(2-4.8); the reflux reaction time is 6-8h.

[0013] Furthermore, the preparation process of the pretreated montmorillonite is as follows:

[0014] 3-Aminopropyltriethoxysilane was added to an aqueous ethanol solution, the pH was adjusted, and the mixture was stirred to hydrolyze. Montmorillonite was then added and refluxed. After the reaction was completed, the mixture was filtered, washed, and dried to obtain pretreated montmorillonite.

[0015] Furthermore, the mass ratio of montmorillonite to 3-aminopropyltriethoxysilane is 1:(0.3-0.6); the concentration of 3-aminopropyltriethoxysilane in the ethanol aqueous solution is 10-30 g / L; the mass concentration of the ethanol aqueous solution is 90%; the pH is adjusted to 3.5-4; the hydrolysis time is 2-3 h; and the reflux reaction time is 5-8 h.

[0016] Furthermore, in step (2), the mass ratio of montmorillonite azidophosphate, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne, copper sulfate, and sodium ascorbate is 5:(3-6):(0.3-0.6):(0.5-1); the mass fraction of montmorillonite azidophosphate in N,N-dimethylformamide is 3-4%; the concentration of the copper sulfate solution is 1 mol / L; the reaction temperature is 45-60℃, and the reaction time is 12-24 h.

[0017] Furthermore, the preparation process of the flame retardant is as follows:

[0018] (a) Quinoline-2,7-diamine was added to anhydrous ethanol, followed by the addition of acetic acid and 3,5-di-tert-butyl-4-hydroxybenzaldehyde. The mixture was refluxed and purified after the reaction was completed to obtain intermediate 1.

[0019] The structural formula of intermediate 1 is as follows:

[0020]

[0021] (b) The intermediate 1,9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added to anhydrous ethanol, stirred and reacted, and purified after the reaction was completed to obtain the flame retardant;

[0022] The structural formula of the flame retardant is as follows:

[0023] .

[0024] The present invention synthesizes the above-mentioned flame retardant by reacting quinoline-2,7-diamine with 3,5-di-tert-butyl-4-hydroxybenzaldehyde to generate a Schiff base intermediate while introducing a hindered phenolic structure. Subsequently, the Schiff base is further reacted with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0025] Further, in step (a), the ratio of quinoline-2,7-diamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, and acetic acid is 1 mmol:(2.2-2.5) mmol:(150-200) μL; the concentration of quinoline-2,7-diamine in anhydrous ethanol is 0.1-0.15 mol / L; and the reflux reaction time is 6-8 h.

[0026] Furthermore, in step (b), the molar ratio of intermediate 1 to 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 2:(4.2-4.5); the stirring reaction is carried out at a temperature of 60-65°C for 16-20 hours.

[0027] Furthermore, the matrix resin is composed of low-density polyethylene and ethylene-ethyl acrylate copolymer in a mass ratio of 5:1; the ethylene-ethyl acrylate copolymer contains 15-20 wt% ethyl acrylate; the coupling agent is selected from one of titanate coupling agents, phosphate coupling agents, and silane coupling agents; the dispersant is selected from one of sodium fatty alcohol polyoxyethylene ether sulfate, ammonium fatty alcohol polyoxyethylene ether sulfate, and sodium lauryl sulfate; the lubricant is one of ethylene bis-stearamide, liquid paraffin, and polyethylene wax; and the compatibilizer is maleic anhydride-grafted polypropylene.

[0028] Furthermore, the density of the low-density polyethylene is 0.916-0.920 g / cm³. 3The melt flow rate at 190℃ / 2.16kg is 8-15g / 10min, and the density of the ethylene-ethyl acrylate copolymer is 0.920-0.930g / cm³. 3 The melt flow rate at 190℃ / 2.16kg is 5-10g / 10min.

[0029] Furthermore, the coupling agent is a silane coupling agent.

[0030] The preparation method of the core material for the above-mentioned Class A fire-resistant metal composite panel includes the following steps:

[0031] According to the stated weight proportions, the matrix resin, flame retardant, modified montmorillonite, coupling agent, dispersant, compatibilizer, and lubricant are mixed and extruded into granules at 170-215°C.

[0032] The beneficial technical effects of this invention are as follows:

[0033] 1. The core material of this invention comprises the following raw materials: matrix resin, flame retardant, modified montmorillonite, coupling agent, dispersant, compatibilizer, and lubricant. This core material exhibits excellent flame retardant properties, antibacterial properties, mechanical properties, and durability.

[0034] 2. This invention improves the mechanical properties and antibacterial properties of the core material and reduces wettability by adding modified montmorillonite. Through modification, this invention successfully introduces both fluorinated alkyl chains (perfluorohexyl) and triazole rings onto the surface of montmorillonite. The grafted perfluorohexyl has extremely low surface energy, significantly reducing the wettability of the material surface, effectively preventing moisture penetration into the core material, and inhibiting interfacial debonding and performance degradation caused by water absorption. The triazole ring, on the other hand, has broad-spectrum antibacterial properties, imparting excellent antibacterial properties to the material, effectively resisting microbial corrosion, and extending the material's service life. Furthermore, the fluorocarbon segments introduced onto the modified montmorillonite surface have good compatibility with the polyethylene segments of the resin matrix, and the triazole ring structure can also interact with the polar segments in the resin matrix through polarity. The two work synergistically to effectively improve the interfacial bonding between the modified montmorillonite and the matrix, enhancing its dispersibility.

[0035] 3. This invention improves the flame retardant and mechanical properties of the core material by adding a flame retardant. This flame retardant works through a phosphorus-nitrogen synergistic effect and a multiphase flame retardant mechanism. Specifically, the analysis is as follows: On the one hand, the phosphorus-phenanthrene structure in the flame retardant molecule decomposes at high temperatures, releasing phosphorus-containing free radicals to generate active free radicals such as PO· and PO2·, effectively capturing H· and OH· free radicals in the combustion chain reaction and interrupting the combustion process; simultaneously, the nitrogen-containing structure releases inert gases, diluting the concentration of combustibles. On the other hand, the phosphorus element in the flame retardant molecule is converted into phosphoric acid substances at high temperatures, acting as a dehydration catalyst to promote the dehydration and carbonization reaction of the resin matrix, transforming the linear polymer chain into a cross-linked aromatic carbon structure; simultaneously, the quinoline ring, phosphorus-phenanthrene, and the aromatic rigid structure in the hindered phenol structure can serve as the carbon layer skeleton, improving the density and structural stability of the carbon layer and preventing the carbon layer from cracking and falling off during combustion. Furthermore, the hindered phenolic structure in this flame retardant molecule contains a 3,5-di-tert-butyl hydrophobic group, which exhibits good compatibility with nonpolar polyethylene segments. It can achieve physical miscibility and prevent phase separation by entanglement with the segments through van der Waals forces. Meanwhile, the phosphorus-oxygen bonds (P=O), -NH- bonds, and tertiary nitrogen atoms on the quinoline ring in the flame retardant molecule can form dipole-dipole interactions or hydrogen bonds with polar segments. This amphoteric structure enables the flame retardant molecules to be uniformly dispersed in the resin matrix, avoiding localized aggregation. Attached Figure Description

[0036] Figure 1 The image shows the infrared spectrum of the modified montmorillonite prepared in Example 4; in the image, curve a is the infrared spectrum of the pretreated montmorillonite, curve b is the infrared spectrum of the azide-treated montmorillonite, and curve c is the infrared spectrum of the modified montmorillonite. Detailed Implementation

[0037] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0038] In this invention, the matrix resin is composed of low-density polyethylene and ethylene-ethyl acrylate copolymer in a mass ratio of 5:1, wherein the density of the low-density polyethylene is 0.916-0.920 g / cm³. 3 The melt flow rate at 190℃ / 2.16kg is 8-15g / 10min, and the density of the ethylene-ethyl acrylate copolymer is 0.920-0.930g / cm³. 3The melt flow rate at 190℃ / 2.16kg is 5-10g / 10min, and the ethyl acrylate content is 15-20wt%.

[0039] The compatibilizer is maleic anhydride-grafted polypropylene, the coupling agent is aminopropyltriethoxysilane, the dispersant is sodium lauryl sulfate, and the lubricant is ethylene bis-stearamide.

[0040] Preparation Example 1

[0041] A pretreated montmorillonite, prepared as follows:

[0042] 3-Aminopropyltriethoxysilane was added to a 90% aqueous ethanol solution to achieve a concentration of 22 g / L. The pH was adjusted to 3.7 with acetic acid, and the mixture was stirred and hydrolyzed for 2.5 h. Then, montmorillonite was added to the hydrolyzed solution at a mass ratio of 1:0.5 to montmorillonite, and the mixture was refluxed for 6 h. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with ethanol and dried under vacuum to obtain pretreated montmorillonite.

[0043] Preparation Example 2

[0044] A pretreated montmorillonite, prepared as follows:

[0045] 3-Aminopropyltriethoxysilane was added to a 90% aqueous ethanol solution to achieve a concentration of 10 g / L. The pH was adjusted to 3.5 with acetic acid, and the mixture was stirred and hydrolyzed for 2 hours. Montmorillonite was added to the hydrolyzed solution at a mass ratio of 1:0.3 to 3-aminopropyltriethoxysilane, and the mixture was refluxed for 5 hours. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with ethanol and dried under vacuum to obtain pretreated montmorillonite.

[0046] Preparation Example 3

[0047] A pretreated montmorillonite, prepared as follows:

[0048] 3-Aminopropyltriethoxysilane was added to a 90% aqueous ethanol solution to obtain a concentration of 30 g / L. The pH was adjusted to 4 with acetic acid and then stirred for 3 h for hydrolysis. Montmorillonite was added to the hydrolyzed solution at a mass ratio of 1:0.6 to 3-aminopropyltriethoxysilane, and the mixture was refluxed for 8 h. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with ethanol and dried under vacuum to obtain pretreated montmorillonite.

[0049] Preparation Example 4

[0050] A modified montmorillonite, prepared as follows:

[0051] ;

[0052] In the synthetic route diagram, the boxes represent montmorillonite.

[0053] (1) Using a ratio of 5g:2.7g:3.5g:140mL for the pretreated montmorillonite, azide-diethylene glycol-bromine, triethylamine, and dichloromethane, the pretreated montmorillonite of Preparation Example 1 was ultrasonically dispersed in dichloromethane, azide-diethylene glycol-bromine and triethylamine were added, and the mixture was refluxed for 7h. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with dichloromethane and deionized water and dried under vacuum to obtain azide-treated montmorillonite.

[0054] (2) The modified montmorillonite was ultrasonically dispersed in N,N-dimethylformamide (DMF) with a mass ratio of 5:4:0.5:0.7 for montmorillonite azidoide, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne, copper sulfate, and sodium ascorbate. The mass fraction of montmorillonite azidoide in DMF was 3.5%. Then, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne (CAS:261503-44-0) was added and fully dissolved. Then, 1 mol / L copper sulfate solution and sodium ascorbate were added. The reaction was carried out at 55°C for 20 h under nitrogen protection. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with acetone and deionized water and dried under vacuum to obtain the modified montmorillonite.

[0055] Preparation Example 5

[0056] A modified montmorillonite, prepared as follows:

[0057] (1) Using a ratio of 5g:1.8g:2g:120mL for pretreated montmorillonite, azido-diethylene glycol-bromine, triethylamine, and dichloromethane, the pretreated montmorillonite of Preparation Example 2 was ultrasonically dispersed in dichloromethane, azido-diethylene glycol-bromine and triethylamine were added, and the mixture was refluxed for 6 hours. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with dichloromethane and deionized water and dried under vacuum to obtain azido-modified montmorillonite.

[0058] (2) The modified montmorillonite was ultrasonically dispersed in N,N-dimethylformamide with a mass ratio of 5:3:0.3:0.5 of montmorillonite azido, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne, copper sulfate, and sodium ascorbate. The mass fraction of montmorillonite azido in DMF was 3%. Then, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne was added and fully dissolved. Then, 1 mol / L copper sulfate solution and sodium ascorbate were added. The reaction was carried out at 45°C for 24 h under nitrogen protection. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with acetone and deionized water and dried under vacuum to obtain the modified montmorillonite.

[0059] Preparation Example 6

[0060] A modified montmorillonite, prepared as follows:

[0061] (1) Using a ratio of 5g:3.6g:4.8g:150mL for pretreated montmorillonite, azide-diethylene glycol-bromine, triethylamine, and dichloromethane, the pretreated montmorillonite of Preparation Example 3 was ultrasonically dispersed in dichloromethane, azide-diethylene glycol-bromine and triethylamine were added, and the mixture was refluxed for 8 hours. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with dichloromethane and deionized water. After vacuum drying, azide-modified montmorillonite was obtained.

[0062] (2) The modified montmorillonite was ultrasonically dispersed in N,N-dimethylformamide (DMF) with a mass ratio of 5:6:0.6:1 for montmorillonite azidocyanide, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne, copper sulfate, and sodium ascorbate. The mass fraction of montmorillonite azidocyanide in DMF was 4%. Then, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne was added and fully dissolved. Then, 1 mol / L copper sulfate solution and sodium ascorbate were added. The reaction was carried out at 60°C for 12 h under nitrogen protection. After the reaction was completed, the reaction solution was filtered, and the filter residue was washed with acetone and deionized water. After vacuum drying, the modified montmorillonite was obtained.

[0063] Preparation Example 7

[0064] A flame retardant, prepared as follows:

[0065]

[0066] (a) Quinoline-2,7-diamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, and acetic acid were added in anhydrous ethanol at a ratio of 1 mmol:2.4 mmol:170 μL. The mixture was heated until completely dissolved. The concentration of quinoline-2,7-diamine in anhydrous ethanol was 0.2 mol / L. Then, acetic acid and 3,5-di-tert-butyl-4-hydroxybenzaldehyde (CAS:1620-98-0) were added, and the mixture was refluxed for 7 h. After the reaction was completed, the reaction solution was cooled to room temperature. The solid product obtained after filtration was washed with cold ethanol and dried under vacuum to obtain intermediate 1 (yield 78.6%). The NMR and mass spectrometry results of intermediate 1 are as follows.

[0067] 1 HNMR: (C 39 H 49 N3O2, 400MHz, DMSO-d6) δ: 1.43 (s, 36H), 7.14-7.18 (d, 1H), 7.40 (s, 2H), 7.50 (s, 4H), 7.72- 7.76 (d, 1H), 7.95 (s, 1H), 8.12-8.16 (d, 1H), 8.44-8.48 (d, 1H), 8.64 (s, 1H), 9.00 (s, 1H); MS (ESI) m / z=591.38[M].

[0068] (b) 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and intermediate 1 were added to anhydrous ethanol at a ratio of 2 mmol:4.4 mmol:25 mL. The mixture was reacted at 62 °C for 18 h. After the reaction was complete, the reaction solution was cooled to room temperature, precipitated with petroleum ether, filtered, and the resulting solid product was recrystallized from ethanol and petroleum ether and dried under vacuum to obtain the flame retardant (yield 80.4%). The NMR and mass spectrometry results of the flame retardant are as follows:

[0069] 1 HNMR: (C 63 H 67 N3O6P2, 400MHz, DMSO-d6) δ: 1.37 (s, 36H), 3.88-3.92 (d, 2H), 6.72 (s, 2H), 6.97 (s, 4H), 7.00 (s, 1H), 7.27-7.31 (m, 3H), 7.34 -7.52 (m, 11H), 7.73-7.77 (m, 2H), 7.90-7.94 (m, 1H), 7.98-8.02 (m, 2H), 8.04 (s, 1H), 8.14-8.18 (m, 1H), 8.50 (s, 1H); MS (ESI) m / z=1023.45[M].

[0070] Preparation Example 8

[0071] A flame retardant, prepared as follows:

[0072] (a) Quinoline-2,7-diamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, and acetic acid were added in anhydrous ethanol at a ratio of 1 mmol:2.5 mmol:200 μL and heated until completely dissolved. The concentration of quinoline-2,7-diamine in anhydrous ethanol was 0.15 mol / L. Then, acetic acid and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were added, and the mixture was refluxed for 8 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered, and the resulting solid product was washed with cold ethanol and dried under vacuum to obtain intermediate 1 (yield 76.9%). The NMR and mass spectrometry results of intermediate 1 were the same as those in preparation example 7.

[0073] (b) With intermediate 1, DOPO and anhydrous ethanol in a ratio of 2 mmol:4.5 mmol:30 mL, DOPO and intermediate 1 were added to anhydrous ethanol and reacted at 65 °C for 16 h. After the reaction was completed, the reaction solution was cooled to room temperature, precipitated with petroleum ether, filtered, and the resulting solid product was recrystallized with ethanol and petroleum ether and dried under vacuum to obtain the flame retardant (yield 78.7%). The NMR and mass spectrometry results of the flame retardant were the same as those in Preparation Example 7.

[0074] Preparation Example 9

[0075] A flame retardant, prepared as follows:

[0076] (a) Quinoline-2,7-diamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, and acetic acid were added in anhydrous ethanol at a ratio of 1 mmol:2.2 mmol:150 μL and heated until completely dissolved. The concentration of quinoline-2,7-diamine in anhydrous ethanol was 0.1 mol / L. Then, acetic acid and 3,5-di-tert-butyl-4-hydroxybenzaldehyde were added, and the mixture was refluxed for 6 h. After the reaction was completed, the reaction solution was cooled to room temperature, filtered, and the resulting solid product was washed with cold ethanol and dried under vacuum to obtain intermediate 1 (yield 77.1%). The NMR and mass spectrometry results of intermediate 1 were the same as those in preparation example 7.

[0077] (b) With intermediate 1, DOPO and anhydrous ethanol in a ratio of 2 mmol:4.2 mmol:20 mL, DOPO and intermediate 1 were added to anhydrous ethanol and reacted at 60 °C for 20 h. After the reaction was completed, the reaction solution was cooled to room temperature, precipitated with petroleum ether, filtered, and the resulting solid product was recrystallized with ethanol and petroleum ether and dried under vacuum to obtain the flame retardant (yield 76.8%). The NMR and mass spectrometry results of the flame retardant were the same as those in Preparation Example 7.

[0078] Example 1

[0079] A core material for a Class A fire-resistant metal composite panel comprises, by weight, the following raw materials: 45 parts of matrix resin, 32 parts of flame retardant of Preparation Example 7, 7 parts of modified montmorillonite of Preparation Example 4, 1 part of coupling agent, 2 parts of dispersant, 2 parts of compatibilizer, and 1 part of lubricant.

[0080] The preparation method of the core material for the above-mentioned Class A fire-resistant metal composite panel includes the following steps:

[0081] According to the above-mentioned weight proportions, add the matrix resin, flame retardant, modified montmorillonite, coupling agent, dispersant, compatibilizer and lubricant to a high-speed mixer, mix at 80℃ and 650r / min for 15min, then transfer to a twin-screw extruder and extrude and granulate at 170-215℃.

[0082] Example 2

[0083] A core material for a Class A fire-resistant metal composite panel comprises, by weight, the following raw materials: 30 parts of matrix resin, 20 parts of flame retardant (Preparation Example 8), 5 parts of modified montmorillonite (Preparation Example 5), 0.5 parts of coupling agent, 0.5 parts of dispersant, 1 part of compatibilizer, and 0.5 parts of lubricant.

[0084] The preparation method of the core material for the above-mentioned Class A fire-resistant metal composite panel includes the following steps:

[0085] According to the above-mentioned weight proportions, add the matrix resin, flame retardant, modified montmorillonite, coupling agent, dispersant, compatibilizer and lubricant to a high-speed mixer, mix at 65℃ and 800r / min for 20min, then transfer to a twin-screw extruder and extrude and granulate at 170-215℃.

[0086] Example 3

[0087] A core material for a Class A fire-resistant metal composite panel comprises, by weight, the following raw materials: 60 parts of matrix resin, 40 parts of flame retardant (Preparation Example 9), 10 parts of modified montmorillonite (Preparation Example 6), 2 parts of coupling agent, 3 parts of dispersant, 3 parts of compatibilizer, and 3 parts of lubricant.

[0088] The preparation method of the core material for the above-mentioned Class A fire-resistant metal composite panel includes the following steps:

[0089] According to the above-mentioned weight proportions, add the matrix resin, flame retardant, modified montmorillonite, coupling agent, dispersant, compatibilizer and lubricant to a high-speed mixer, mix at 90℃ and 600r / min for 10min, then transfer to a twin-screw extruder and extrude and granulate at 170-215℃.

[0090] Comparative Example 1

[0091] Based on Example 1, DOPO was used instead of the flame retardant in Preparation Example 7 to form Comparative Example 1.

[0092] Comparative Example 2

[0093] Based on Example 1, montmorillonite was used instead of the modified montmorillonite in Preparation Example 4 to form Comparative Example 2.

[0094] Experimental Example 1

[0095] The modified montmorillonite prepared in Example 4 was analyzed by Fourier transform infrared spectroscopy (FT-IR), and the results are as follows: Figure 1 As shown.

[0096] Figure 1 This is the infrared spectrum of the modified montmorillonite obtained in Preparation Example 4. In the figure, curve a is the infrared spectrum of the pretreated montmorillonite, curve b is the infrared spectrum of the azide-treated montmorillonite, and curve c is the infrared spectrum of the modified montmorillonite. Observation Figure 1 It is known that: compared to pretreated montmorillonite, azide-treated montmorillonite at 3500cm... -1 The characteristic absorption peak of the amino group around the 2117 cm⁻¹ decreased, and the peak at 2117 cm⁻¹ decreased. -1 The presence of characteristic absorption peaks for azide groups at 2520 and 1410 cm⁻¹ indicates the successful preparation of azido-modified montmorillonite. Compared to azido-modified montmorillonite, modified montmorillonite exhibits higher absorption peaks at 2520 and 1410 cm⁻¹. -1 Characteristic absorption peaks for C=CN=N and C=C appear at 2117 cm⁻¹. -1 The disappearance of the characteristic absorption peak of the azide group indicates that the modified montmorillonite was successfully prepared.

[0097] Experimental Example 2

[0098] To compare and illustrate the performance of different core materials, the following properties of the core materials obtained in the examples and comparative examples were tested.

[0099] The preparation of aluminum-plastic composite panel specimens for each test item shall refer to GB / T17748-2016. The specifications of the aluminum-plastic composite panel specimens are as follows: total thickness is 4mm, aluminum alloy steel plate thickness is 0.5mm, and molecular film thickness is 0.05mm.

[0100] Saturated water absorption rate: Tested according to GB / T 1034-2008, the results are shown in Table 1;

[0101] Antibacterial properties: Tested according to QB / T2591-2003. Staphylococcus aureus and Escherichia coli were inoculated on the core materials of Examples 1-3 and Comparative Examples 1-2, respectively. The results are shown in Table 1.

[0102] Elongation at break: Tested according to GB / 1040-2018, the results are shown in Table 1;

[0103] Roller peel strength (tested on aluminum-plastic composite panels): The test was conducted in accordance with GB / 17748-2016, and the results are shown in Table 1.

[0104] Combustion performance (tested on aluminum-plastic composite panels): Minimum remaining length after combustion, average remaining length after combustion, and average flue gas temperature were tested according to GB / T 8625-2005; smoke density rating was tested according to GB / T 8627-2007. The evaluation standards were: Grade A: Minimum remaining length after combustion > 200 mm, average remaining length after combustion ≥ 350 mm, flue gas temperature ≤ 125℃, smoke density rating ≤ 15; Grade B1: Minimum remaining length after combustion > 0 mm, average remaining length after combustion ≥ 150 mm, flue gas temperature ≤ 200℃, smoke density rating ≤ 75. Results are shown in Table 2.

[0105] Table 1

[0106]

[0107] Table 2

[0108]

[0109] As shown in Table 1, compared with Comparative Example 2, the core material prepared by adding modified montmorillonite in Example 1 has excellent mechanical properties, antibacterial properties, and a lower saturated water absorption rate. The above experimental results indicate that modified montmorillonite can improve the mechanical properties and antibacterial properties of the core material and reduce wettability. In this invention, montmorillonite is first pretreated with 3-aminopropyltriethoxysilane through surface amination; then, an azide group is introduced through a nucleophilic substitution reaction between amino groups and azido-diethylene glycol-bromine; finally, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne is grafted onto the surface of montmorillonite through an azide-alkynyl click chemistry reaction. Through the above modifications, fluorinated alkyl chains (perfluorohexyl) and triazole rings were successfully introduced simultaneously onto the surface of montmorillonite. The grafted perfluorohexyl possesses extremely low surface energy, significantly reducing the wettability of the material surface, effectively preventing moisture penetration into the core material, and inhibiting interfacial debonding and performance degradation caused by water absorption. Meanwhile, the triazole ring exhibits broad-spectrum antibacterial properties, endowing the material with excellent antibacterial properties, effectively resisting microbial corrosion, and extending the material's service life. Furthermore, the fluorocarbon segments introduced onto the modified montmorillonite surface have good compatibility with the polyethylene segments of the resin matrix, and the triazole ring structure can also interact with the polar segments in the resin matrix through polarity. The synergistic effect of both effectively improves the interfacial bonding between the modified montmorillonite and the matrix, enhancing its dispersibility.

[0110] As shown in Tables 1-2, compared with Comparative Example 1, the core material prepared by adding flame retardant in Example 1 exhibits superior flame retardant and mechanical properties. The above experimental results demonstrate that flame retardant can improve the flame retardant and mechanical properties of the core material. This flame retardant works through a phosphorus-nitrogen synergistic effect and a multiphase flame retardant mechanism. Specifically, the analysis is as follows: On the one hand, the phosphorus-phenanthrene structure in the flame retardant molecule decomposes at high temperatures, releasing phosphorus-containing free radicals to generate active free radicals such as PO· and PO2·, effectively capturing H· and OH· free radicals in the combustion chain reaction and interrupting the combustion process; simultaneously, the nitrogen-containing structure releases inert gases, diluting the concentration of combustibles; on the other hand, the phosphorus element in the flame retardant molecule is converted into phosphoric acid substances at high temperatures, acting as a dehydration catalyst to promote the dehydration and carbonization reaction of the resin matrix, transforming the linear polymer chain into a cross-linked aromatic carbon structure; simultaneously, the quinoline ring, phosphorus-phenanthrene, and the aromatic rigid structure in the hindered phenol structure can serve as the carbon layer skeleton, improving the density and structural stability of the carbon layer and preventing the carbon layer from cracking and falling off during combustion.

[0111] Furthermore, the hindered phenolic structure in this flame retardant molecule contains a 3,5-di-tert-butyl hydrophobic group, which exhibits good compatibility with nonpolar polyethylene segments. It can achieve physical miscibility and prevent phase separation by entanglement with the segments through van der Waals forces. Meanwhile, the phosphorus-oxygen bonds (P=O), -NH- bonds, and tertiary nitrogen atoms on the quinoline ring in the flame retardant molecule can form dipole-dipole interactions or hydrogen bonds with polar segments. This amphoteric structure enables the flame retardant molecules to be uniformly dispersed in the resin matrix, avoiding localized aggregation.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A core material for Class A fire-resistant metal composite panels, characterized in that, By weight, it includes the following raw materials: 30-60 parts of matrix resin, 20-40 parts of flame retardant, 5-10 parts of modified montmorillonite, 0.5-2 parts of coupling agent, 0.5-3 parts of dispersant, 1-3 parts of compatibilizer, and 0.5-3 parts of lubricant. The preparation process of the modified montmorillonite is as follows: (1) Add the pretreated montmorillonite to dichloromethane, then add azide-diethylene glycol-bromine and triethylamine, reflux the reaction, filter, wash and dry after the reaction is complete to obtain azide-modified montmorillonite; (2) Add the azido-modified montmorillonite to N,N-dimethylformamide, then add 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne, then add copper sulfate solution and sodium ascorbate, react under inert gas protection, filter, wash and dry after the reaction is completed to obtain the modified montmorillonite; The preparation process of the pretreated montmorillonite in step (1) is as follows: 3-aminopropyltriethoxysilane is added to an aqueous ethanol solution, the pH is adjusted and then stirred for hydrolysis, then montmorillonite is added for reflux reaction, after the reaction is completed, the mixture is filtered, washed and dried to obtain the pretreated montmorillonite. The structural formula of the flame retardant is: ； The matrix resin is composed of low-density polyethylene and ethylene-ethyl acrylate copolymer in a mass ratio of 5:

1.

2. The core material for Class A fire-resistant metal composite panels according to claim 1, characterized in that, In step (1), the mass ratio of pretreated montmorillonite, azide-diethylene glycol-bromine, and triethylamine is 5:(1.8-3.6):(2-4.8); the reflux reaction time is 6-8 h.

3. The core material for Class A fire-resistant metal composite panels according to claim 1, characterized in that, The mass ratio of montmorillonite to 3-aminopropyltriethoxysilane is 1:(0.3-0.6); the concentration of 3-aminopropyltriethoxysilane in the ethanol aqueous solution is 10-30 g / L; the mass concentration of the ethanol aqueous solution is 90%; the pH is adjusted to 3.5-4; the hydrolysis time is 2-3 h; and the reflux reaction time is 5-8 h.

4. The core material for Class A fire-resistant metal composite panels according to claim 1, characterized in that, In step (2), the mass ratio of montmorillonite azidophosphate, 4,4,5,5,6,6,6-heptafluoro-3,3-di(trifluoromethyl)-1-hexyne, copper sulfate, and sodium ascorbate is 5:(3-6):(0.3-0.6):(0.5-1); the mass fraction of montmorillonite azidophosphate in N,N-dimethylformamide is 3-4%; the concentration of the copper sulfate solution is 1 mol / L; the reaction temperature is 45-60℃, and the reaction time is 12-24 h.

5. The core material for Class A fire-resistant metal composite panels according to claim 1, characterized in that, The preparation process of the flame retardant is as follows: (a) Quinoline-2,7-diamine was added to anhydrous ethanol, followed by the addition of acetic acid and 3,5-di-tert-butyl-4-hydroxybenzaldehyde. The mixture was refluxed and purified after the reaction was completed to obtain intermediate 1. The structural formula of intermediate 1 is as follows: (b) The intermediate 1,9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide was added to anhydrous ethanol, stirred and reacted, and purified after the reaction was completed to obtain the flame retardant.

6. The core material for Class A fire-resistant metal composite panels according to claim 5, characterized in that, In step (a), the ratio of quinoline-2,7-diamine, 3,5-di-tert-butyl-4-hydroxybenzaldehyde, and acetic acid is 1 mmol:(2.2-2.5) mmol:(150-200) μL; the concentration of quinoline-2,7-diamine in anhydrous ethanol is 0.1-0.15 mol / L; and the reflux reaction time is 6-8 h.

7. The core material for Class A fire-resistant metal composite panels according to claim 5, characterized in that, The molar ratio of intermediate 1 and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in step (b) is 2:(4.2-4.5); the stirring reaction is carried out at a temperature of 60-65°C for 16-20 hours.

8. The core material for Class A fire-resistant metal composite panels according to claim 1, characterized in that, The ethylene-ethyl acrylate copolymer contains 15-20 wt% ethyl acrylate; the coupling agent is selected from one of titanate coupling agents, phosphate coupling agents, and silane coupling agents; the dispersant is selected from one of sodium fatty alcohol polyoxyethylene ether sulfate, ammonium fatty alcohol polyoxyethylene ether sulfate, and sodium lauryl sulfate; the lubricant is one of ethylene bis-stearamide, liquid paraffin, and polyethylene wax; and the compatibilizer is maleic anhydride-grafted polypropylene.

9. A method for preparing the core material for a Class A fire-resistant metal composite panel according to any one of claims 1-8, characterized in that, Includes the following steps: According to the stated weight proportions, the matrix resin, flame retardant, modified montmorillonite, coupling agent, dispersant, compatibilizer, and lubricant are mixed and extruded into granules at 170-215°C.

Images