Flame-retardant heat-insulating aluminum foil reinforced composite material and preparation method thereof

Abstract

The invention discloses a flame-retardant heat-insulating aluminum foil reinforced composite material and a preparation method thereof, and belongs to the technical field of aluminum foil reinforced composite materials. The flame-retardant heat-insulating aluminum foil reinforced composite material prepared by the invention sequentially comprises an aluminum foil layer, a reinforced net, kraft paper and a flame-retardant adhesive layer for bonding the aluminum foil layer and the reinforced net and bonding the reinforced net and the kraft paper from bottom to top, the flame-retardant adhesive layer comprises the following raw material components: a dianhydride monomer, an amine monomer and a heat-insulating filler; the amine monomer comprises 4, 4 '-diaminodiphenyl ether, flame-retardant diaminobenzimidazole and 4-aminobenzonitrile, the heat-insulating filler is prepared from hydroxyapatite nanowires, montmorillonite nanosheets and aminated polyvinyl alcohol, and the flame-retardant heat-insulating aluminum foil reinforced composite material prepared by the preparation method disclosed by the invention is relatively good in flame retardance and heat insulation.

Description

Technical Field

[0001] This invention relates to aluminum foil reinforced composite materials, specifically a flame-retardant and heat-insulating aluminum foil reinforced composite material and its preparation method. Background Technology

[0002] With the increasing demand for high-performance composite materials in fields such as building energy conservation, transportation, aerospace, and electronics, functional composite materials that combine lightweight, high strength, thermal insulation, and flame retardancy are receiving increasing attention. Aluminum foil reinforced composite materials, as a typical layered functional material, have been widely used in building insulation, cold chain packaging, fireproof partitions, and high-temperature protection due to their excellent reflective properties, good mechanical strength, and certain thermal insulation effects.

[0003] Traditional aluminum foil reinforced composite materials typically consist of two layers of aluminum foil sandwiching a layer of fiber-reinforced reinforcing material (such as fiberglass cloth or polyester nonwoven fabric) and then hot-pressing them together with an adhesive. While this structure possesses certain thermal insulation and tensile strength properties, it still has significant shortcomings in practical applications: Firstly, ordinary adhesives and core materials are mostly organic polymers, which are flammable, decompose, or even release toxic fumes under high temperatures or open flame conditions, making it difficult to meet increasingly stringent fire safety standards. Secondly, existing structures have limited ability to suppress heat conduction, especially under long-term high-temperature or extreme temperature difference environments, where their thermal insulation performance significantly decreases, limiting their application in high-end thermal insulation and protection scenarios.

[0004] Therefore, there is an urgent need to develop a flame-retardant and heat-insulating aluminum foil reinforced composite material that combines excellent flame retardancy and high-efficiency heat insulation performance. Summary of the Invention

[0005] The purpose of this invention is to provide a flame-retardant and heat-insulating aluminum foil reinforced composite material and its preparation method, so as to solve the technical problems mentioned in the background art.

[0006] The technical solution to achieve the objective of this invention is: In a first aspect, the present invention provides a flame-retardant and heat-insulating aluminum foil reinforced composite material, comprising, from bottom to top, an aluminum foil layer, a reinforcing mesh, kraft paper, and a flame-retardant adhesive layer for bonding the aluminum foil layer to the reinforcing mesh and the reinforcing mesh to the kraft paper.

[0007] Furthermore, the raw material components of the flame-retardant adhesive layer include dianhydride monomers, amine monomers, and heat-insulating fillers.

[0008] The dianhydride monomer includes 4,4'-(hexafluoroisopropene) diaphthalic anhydride.

[0009] Furthermore, the amine monomers include 4,4'-diaminodiphenyl ether, flame-retardant diaminobenzimidazole, and 4-aminobenzonitrile.

[0010] Furthermore, the flame-retardant diaminobenzimidazole is obtained by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with 2-(4-aminophenyl)-5-aminobenzimidazole.

[0011] Furthermore, the heat-insulating filler is made of hydroxyapatite nanowires, montmorillonite nanosheets, and amino-modified polyvinyl alcohol.

[0012] In a second aspect, the present invention provides a method for preparing a flame-retardant and heat-insulating aluminum foil reinforced composite material as described in the first aspect, the steps of which include: (1) Coat one side of the kraft paper with a heat-insulating adhesive layer, then lay fiberglass cloth on the high-temperature resistant adhesive layer and heat-cur it to obtain a kraft paper / fiberglass cloth composite layer; (2) A heat-insulating adhesive layer is coated on the outside of the fiberglass cloth of the kraft paper-fiberglass cloth composite material, and then aluminum foil is laid on the high-temperature resistant adhesive layer and then heated and cured to obtain a flame-retardant heat-insulating aluminum foil reinforced composite material.

[0013] Further, the preparation method of the heat-insulating adhesive layer is as follows: under nitrogen protection, the heat-insulating filler is uniformly dispersed in N-methylpyrrolidone, then an amine monomer is added and stirred for 60-90 min, followed by the addition of dianhydride monomer, and stirring is continued at room temperature for 5-7 h to obtain the heat-insulating adhesive layer; the molar ratio of amine monomer to dianhydride monomer is 1:(1.2-1.5); the amount of heat-insulating filler added is 0.03-0.1 times the total mass of dianhydride monomer and amine monomer.

[0014] Further, the molar ratio of 4,4'-diaminodiphenyl ether, flame-retardant diaminobenzimidazole, and 4-aminobenzonitrile in the amine monomer is (3~4):(1~2):(1~2); the preparation steps of the flame-retardant diaminobenzimidazole are as follows: under nitrogen protection, 5 parts by mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are dissolved in 12~15 parts by mass of acetonitrile, and then 3~3.2 parts by mass of sulfonyl chloride are added dropwise. Then the mixture is heated under reflux for 55~65 min and cooled to room temperature to obtain solution A; 5.7~6 parts by mass of 2-(4-aminophenyl)-5-aminobenzimidazole and 5.1~5.3 parts by mass of triethylamine are dissolved in acetonitrile and stirred thoroughly. Solution A is then added dropwise, and the mixture is stirred at 75~85℃ for 9~11 h. After cooling to room temperature, the mixture is filtered, washed, and dried to obtain flame-retardant diaminobenzimidazole.

[0015] Further, the preparation steps of the heat-insulating filler are as follows: 5 parts by mass of aminated polyvinyl alcohol are added to 48-52 parts by mass of deionized water, heated in a water bath at 88-92°C for 3-5 hours, then 54-56 parts by mass of the exfoliated montmorillonite nanosheet solution are added and stirred to disperse evenly. Then 0.1-0.3 parts by mass of hydroxyapatite nanowires are added and stirred for 1-3 hours. The mixture is then poured into a mold, directionally frozen for 18-22 minutes, and freeze-dried for 71-73 hours to obtain the heat-insulating filler. The preparation steps of the exfoliated montmorillonite nanosheet solution are as follows: 4-6 parts by mass of montmorillonite nanosheets are added to 50 parts by mass of deionized water and stirred rapidly for 23-25 ​​hours to obtain the exfoliated montmorillonite nanosheet solution.

[0016] The preparation steps of the aminated polyvinyl alcohol are as follows: Under stirring conditions, 50 parts by mass of a polyvinyl alcohol aqueous solution with a mass-to-volume ratio of 8g:100mL and 0.4-0.5 parts by mass of 1-amino-3-chloropropane hydrochloride are added, and then the temperature is raised to 75-85℃. 3.6-4 parts by mass of a sodium hydroxide solution with a mass-to-volume ratio of 10g:100mL are added, and the reaction is maintained at this temperature for 8-10 hours. After the reaction is completed, the solution is adjusted to neutral with hydrochloric acid, cooled to room temperature, and then poured into 400-500 parts by mass of anhydrous ethanol. The mixture is stirred and washed thoroughly, and then vacuum filtered to obtain the aminated polyvinyl alcohol.

[0017] Furthermore, the heating and curing step includes: first heating to 60℃ and holding for 4~6 hours, then heating to 120~180℃ at 35~45℃ / min and holding for 1~2 hours, and finally heating to 370~380℃ and holding for 1~3 hours.

[0018] By adopting the above technical solution, the present invention has the following beneficial effects: (1) The flame-retardant and heat-insulating aluminum foil reinforced composite material of the present invention comprises, from bottom to top, an aluminum foil layer, a reinforcing mesh, kraft paper, and a flame-retardant adhesive layer for bonding the aluminum foil layer and the reinforcing mesh, and the reinforcing mesh and the kraft paper: wherein, the aluminum foil layer has high reflectivity, which can effectively reflect heat radiation and significantly reduce heat transfer; the reinforcing mesh, as a reinforcing skeleton, not only improves the overall mechanical strength and dimensional stability of the material, but also forms a microporous structure to hinder heat convection; the kraft paper, as an intermediate heat insulation layer, has a natural fiber structure rich in still air, which further inhibits heat conduction; and the flame-retardant adhesive layer introduces flame-retardant components while bonding the functional layers, so that the resulting flame-retardant and heat-insulating aluminum foil reinforced composite material has both excellent flame retardancy and high-efficiency heat insulation performance.

[0019] (2) The heat insulation filler of the present invention is made of hydroxyapatite nanowires, montmorillonite nanosheets and aminated polyvinyl alcohol; aminated polyvinyl alcohol is obtained by reacting the chlorine atoms on 1-amino-3-chloropropane hydrochloride with the hydroxyl groups on polyvinyl alcohol. Since the surfaces of aminated polyvinyl alcohol, montmorillonite nanosheets and hydroxyapatite nanowires are rich in hydroxyl groups, these hydroxyl groups are easy to form intermolecular hydrogen bonds during stirring, thereby significantly enhancing the interfacial bonding force between the components and improving the overall structural stability of the composite aerogel; at the same time, the one-dimensional hydroxyapatite nanowires and the two-dimensional sheet-like montmorillonite nanosheets are intertwined and interwoven in the dispersion system to construct a dense and continuous three-dimensional interpenetrating network structure, which effectively suppresses the heat conduction path; combined with the directional freezing process, the ice crystals grow in a single direction, guide the orderly arrangement of the internal pores of the aerogel, and achieve a high degree of uniformity of the pore structure; not only does it greatly reduce the solid phase heat conduction of the material, but it also restricts the gas phase heat transfer and convection, significantly reducing the thermal conductivity of the heat insulation filler.

[0020] (3) The flame-retardant diaminobenzimidazole of the present invention is obtained by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with 2-(4-aminophenyl)-5-aminobenzimidazole. Specifically, the phosphorus-hydrogen bond in 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) reacts with the nitrogen-hydrogen bond on the imidazole ring of 2-(4-aminophenyl)-5-aminobenzimidazole to form a stable PN covalent bond, thereby forming a stable PN covalent bond. Grafting 9-oxa-10-phosphaphenanthrene-10-oxide onto 2-(4-aminophenyl)-5-aminobenzimidazole not only retains the original thermal stability and rigidity of benzimidazole, but also introduces the highly efficient gas-phase and condensed-phase synergistic flame-retardant mechanism unique to DOPO: during heating or combustion, DOPO can release phosphorus-containing free radicals to capture highly active free radicals to interrupt the combustion chain reaction, while promoting char formation and forming a dense and continuous char layer, effectively enhancing the flame-retardant performance of the flame-retardant adhesive layer.

[0021] (4) The raw material components of the flame-retardant adhesive layer of the present invention include dianhydride monomers, amine monomers, and heat-insulating fillers; wherein, the dianhydride monomers include 4,4'-(hexafluoroisopropene)phthalic anhydride, whose molecular structure contains hexafluoroisopropene groups that not only endow the polymer backbone with excellent thermal stability and low dielectric constant, but also effectively reduce the surface energy of the material, improve hydrophobicity and weather resistance, and provide a guarantee for the long-term service of the adhesive layer in high temperature or humid environment; the amine monomers include 4,4'-diaminodiphenyl ether, flame-retardant diaminobenzimidazole, and 4-aminobenzonitrile, and the heat-insulating fillers are made of hydroxyapatite nanowires, montmorillonite nanosheets, and aminated polyvinyl alcohol; during the preparation of the flame-retardant adhesive layer, the dianhydride monomers react with the amine monomers and the amino groups on the heat-insulating fillers to form an amic acid polymer containing cyanide-terminated groups, which is then... The process involves a gradient temperature curing process: initial cross-linking is performed at 60℃ to stabilize the system, followed by heating to 120-180℃ to promote partial cyclization and dehydration of the amyl acid, forming a polyimide prepolymer containing cyano-terminated groups; finally, deep curing is completed at a high temperature of 370-380℃, causing the cyano-terminated groups to undergo trimerization and cyclization, generating a hyperbranched three-dimensional network structure with triazine rings as branching centers and polyimide chains as branches; this structure forms a large number of nanoscale cavities, significantly reducing the solid-phase heat transfer path, thereby enhancing the thermal insulation performance; at the same time, the triazine ring itself has a high char formation rate and thermal stability, which works synergistically with the phosphorus-based active substances released by the flame-retardant diaminobenzimidazole and the physical barrier formed by the thermal insulation filler, jointly inhibiting the combustion process in both the gas phase and the condensed phase, further improving the flame-retardant performance of the flame-retardant adhesive layer. Detailed Implementation

[0022] To better understand the above technical solution, the following will provide a detailed explanation of the technical solution in conjunction with specific implementation methods.

[0023] Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention.

[0024] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and should not be used to limit the scope of protection of the present invention.

[0025] The aluminum foil layer is 20μm thick.

[0026] The thickness of the kraft paper layer is 30μm.

[0027] Fiberglass cloth with a strength of 170g / m 2 Medium-alkali fiberglass cloth.

[0028] Polyvinyl alcohol used is polyvinyl alcohol 1750±50.

[0029] The montmorillonite nanosheets used sodium-based montmorillonite, which was purchased from Shanghai Sinopharm Chemical Reagent Co., Ltd.

[0030] The preparation steps of hydroxyapatite nanowires are as follows: 0.88g of anhydrous calcium chloride, 4g of sodium hydroxide, and 1.12g of sodium dihydrogen phosphate were dissolved in 80g, 80g, and 40g of deionized water, respectively, and stirred for 15min to obtain calcium chloride solution, sodium hydroxide solution, and sodium dihydrogen phosphate solution. 48g of ethanol and 48g of oleic acid were mixed and stirred for 20min to obtain a mixed solution of ethanol and oleic acid. The calcium chloride solution was added dropwise to the mixed solution of ethanol and oleic acid and stirred for 1h. Then, sodium hydroxide solution was added dropwise and stirred for another 1h. Then, sodium dihydrogen phosphate solution was added dropwise and stirred for another 1h. The mixture was then poured into the lining of a Teflon reactor and placed in the reactor. The reactor was then dried in a drying oven at 180℃ for 24h. After the reaction was completed, the precipitate was placed in 100mL of ethanol to grow into a flocculent precipitate. The precipitate was then filtered and dried to obtain hydroxyapatite nanowires. Example 1

[0031] A method for preparing a flame-retardant and heat-insulating aluminum foil reinforced composite material, comprising the following steps: (1) Coat one side of the kraft paper with a 30μm thick heat-insulating adhesive layer, then lay fiberglass cloth on the high-temperature resistant adhesive layer and heat-cur it to obtain a kraft paper / fiberglass cloth composite layer. (2) A 30μm thick heat-insulating adhesive layer is coated on the outside of the glass fiber cloth of the kraft paper-glass fiber cloth composite material. Then, aluminum foil is laid on the high-temperature resistant adhesive layer. Then, the temperature is first raised to 60℃ and kept for 4h, then raised to 120℃ at 35℃ / min and kept for 2h, and finally raised to 370℃ and kept for 3h to obtain a flame-retardant heat-insulating aluminum foil reinforced composite material.

[0032] The preparation method of the heat-insulating adhesive layer is as follows: Under nitrogen protection, 0.14 parts by mass of heat-insulating filler are uniformly dispersed in N-methylpyrrolidone, and then 0.8 parts by mass of 4,4'-diaminodiphenyl ether, 0.44 parts by mass of flame-retardant diaminobenzimidazole, and 0.12 parts by mass of 4-aminobenzonitrile are added and stirred for 60 min. Then, 3.2 parts by mass of 4,4'-(hexafluoroisopropene)phthalic anhydride are added and stirred at room temperature for 5 h to obtain the heat-insulating adhesive layer.

[0033] The preparation steps of flame-retardant diaminobenzimidazole are as follows: Under nitrogen protection, 5 parts by mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were dissolved in 12 parts by mass of acetonitrile, and then 3 parts by mass of sulfonyl chloride were added dropwise. The mixture was then heated under reflux for 55 min and cooled to room temperature to obtain solution A. 5.7 parts by mass of 2-(4-aminophenyl)-5-aminobenzimidazole and 5.1 parts by mass of triethylamine were dissolved in acetonitrile and stirred thoroughly. Solution A was then added dropwise, and the mixture was stirred at 75 °C for 9 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain flame-retardant diaminobenzimidazole.

[0034] The preparation steps of the heat insulation filler are as follows: 5 parts by mass of aminated polyvinyl alcohol are added to 48 parts by mass of deionized water, heated in a water bath at 88°C for 3 hours, then 54 parts by mass of exfoliated montmorillonite nanosheet solution are added and stirred to disperse evenly. Then 0.1 parts by mass of hydroxyapatite nanowires are added and stirred for 1 hour. The mixture is then poured into a mold, directionally frozen for 18 minutes, and freeze-dried for 71 hours to obtain the heat insulation filler. The preparation steps of the exfoliated montmorillonite nanosheet solution are as follows: 4 parts by mass of montmorillonite nanosheets are added to 50 parts by mass of deionized water and stirred rapidly for 23 hours to obtain the exfoliated montmorillonite nanosheet solution.

[0035] The preparation steps of aminated polyvinyl alcohol are as follows: Under stirring conditions, 50 parts by mass of a polyvinyl alcohol aqueous solution with a mass-to-volume ratio of 8 g:100 mL and 0.4 parts by mass of 1-amino-3-chloropropane hydrochloride are added, and then the temperature is raised to 75℃. 3.6 parts by mass of a sodium hydroxide solution with a mass-to-volume ratio of 10 g:100 mL are added, and the reaction is maintained at this temperature for 8 h. After the reaction is completed, the solution is adjusted to neutral with hydrochloric acid, cooled to room temperature, and then poured into 400 parts by mass of anhydrous ethanol. The mixture is stirred and washed thoroughly, and then vacuum filtered to obtain aminated polyvinyl alcohol. Example 2

[0036] A method for preparing a flame-retardant and heat-insulating aluminum foil reinforced composite material, comprising the following steps: (1) Coat one side of the kraft paper with a 30μm thick heat-insulating adhesive layer, then lay fiberglass cloth on the high-temperature resistant adhesive layer and heat-cur it to obtain a kraft paper / fiberglass cloth composite layer. (2) A 30μm thick heat-insulating adhesive layer is coated on the outside of the glass fiber cloth of the kraft paper-glass fiber cloth composite material. Then, aluminum foil is laid on the high-temperature resistant adhesive layer. Then, the temperature is first raised to 60℃ and kept for 5h, then raised to 150℃ at 40℃ / min and kept for 2h, and finally raised to 380℃ and kept for 2h to obtain a flame-retardant heat-insulating aluminum foil reinforced composite material.

[0037] The preparation method of the heat-insulating adhesive layer is as follows: Under nitrogen protection, 0.66 parts by mass of heat-insulating filler are uniformly dispersed in N-methylpyrrolidone, then 3.5 parts by mass of 4,4'-diaminodiphenyl ether, 0.66 parts by mass of flame-retardant diaminobenzimidazole, and 0.18 parts by mass of 4-aminobenzonitrile are added and stirred for 75 min. Then 3.9 parts by mass of 4,4'-(hexafluoroisopropene)phthalic anhydride are added and stirred at room temperature for 6 h to obtain the heat-insulating adhesive layer.

[0038] The preparation steps of flame-retardant diaminobenzimidazole are as follows: Under nitrogen protection, 5 parts by mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were dissolved in 14 parts by mass of acetonitrile, and then 3.1 parts by mass of sulfonyl chloride were added dropwise. The mixture was then heated under reflux for 60 min and cooled to room temperature to obtain solution A. 5.9 parts by mass of 2-(4-aminophenyl)-5-aminobenzimidazole and 5.2 parts by mass of triethylamine were dissolved in acetonitrile and stirred thoroughly. Solution A was then added dropwise, and the mixture was stirred at 80 °C for 10 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain flame-retardant diaminobenzimidazole.

[0039] The preparation steps of the heat insulation filler are as follows: 5 parts by mass of aminated polyvinyl alcohol are added to 50 parts by mass of deionized water, heated in a water bath at 90°C for 4 hours, then 55 parts by mass of exfoliated montmorillonite nanosheet solution are added and stirred to disperse evenly. Then 0.2 parts by mass of hydroxyapatite nanowires are added and stirred for another 2 hours. The mixture is then poured into a mold, directionally frozen for 20 minutes, and then freeze-dried for 72 hours to obtain the heat insulation filler. The preparation steps of the exfoliated montmorillonite nanosheet solution are as follows: 5 parts by mass of montmorillonite nanosheets are added to 50 parts by mass of deionized water and stirred rapidly for 24 hours to obtain the exfoliated montmorillonite nanosheet solution.

[0040] The preparation steps of aminated polyvinyl alcohol are as follows: Under stirring conditions, 50 parts by mass of a polyvinyl alcohol aqueous solution with a mass-to-volume ratio of 8 g:100 mL and 0.45 parts by mass of 1-amino-3-chloropropane hydrochloride are added, and then the temperature is raised to 80℃. 3.8 parts by mass of a sodium hydroxide solution with a mass-to-volume ratio of 10 g:100 mL are added, and the reaction is maintained at this temperature for 9 h. After the reaction is completed, the solution is adjusted to neutral with hydrochloric acid, cooled to room temperature, and then poured into 450 parts by mass of anhydrous ethanol. The mixture is thoroughly stirred and washed, and then vacuum filtered to obtain aminated polyvinyl alcohol. Example 3

[0041] A method for preparing a flame-retardant and heat-insulating aluminum foil reinforced composite material, comprising the following steps: (1) Coat one side of the kraft paper with a 30μm thick heat-insulating adhesive layer, then lay fiberglass cloth on the high-temperature resistant adhesive layer and heat-cur it to obtain a kraft paper / fiberglass cloth composite layer. (2) A 30μm thick heat-insulating adhesive layer is coated on the outside of the glass fiber cloth of the kraft paper-glass fiber cloth composite material. Then, aluminum foil is laid on the high-temperature resistant adhesive layer. Then, the temperature is first raised to 60℃ and kept for 6h, then raised to 180℃ at 45℃ / min and kept for 1h, and finally raised to 380℃ and kept for 1h to obtain a flame-retardant heat-insulating aluminum foil reinforced composite material.

[0042] The preparation method of the heat-insulating adhesive layer is as follows: Under nitrogen protection, 0.54 parts by mass of heat-insulating filler are uniformly dispersed in N-methylpyrrolidone, and then 0.6 parts by mass of 4,4'-diaminodiphenyl ether, 0.88 parts by mass of flame-retardant diaminobenzimidazole, and 0.23 parts by mass of 4-aminobenzonitrile are added and stirred for 90 min. Then, 4.7 parts by mass of 4,4'-(hexafluoroisopropene)phthalic anhydride are added and stirred at room temperature for 7 h to obtain the heat-insulating adhesive layer.

[0043] The preparation steps of flame-retardant diaminobenzimidazole are as follows: Under nitrogen protection, 5 parts by mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were dissolved in 15 parts by mass of acetonitrile, and then 3.2 parts by mass of sulfonyl chloride were added dropwise. The mixture was then heated under reflux for 65 min and cooled to room temperature to obtain solution A. 6 parts by mass of 2-(4-aminophenyl)-5-aminobenzimidazole and 5.3 parts by mass of triethylamine were dissolved in acetonitrile and stirred thoroughly. Solution A was then added dropwise, and the mixture was stirred at 85 °C for 11 h. After cooling to room temperature, the mixture was filtered, washed, and dried to obtain flame-retardant diaminobenzimidazole.

[0044] The preparation steps of the heat insulation filler are as follows: 5 parts by mass of aminated polyvinyl alcohol are added to 52 parts by mass of deionized water, heated in a water bath at 92°C for 5 hours, then 56 parts by mass of exfoliated montmorillonite nanosheet solution are added and stirred to disperse evenly. Then 0.3 parts by mass of hydroxyapatite nanowires are added and stirred for 3 hours. The mixture is then poured into a mold, directionally frozen for 22 minutes, and then freeze-dried for 73 hours to obtain the heat insulation filler. The preparation steps of the exfoliated montmorillonite nanosheet solution are as follows: 6 parts by mass of montmorillonite nanosheets are added to 50 parts by mass of deionized water and stirred rapidly for 25 hours to obtain the exfoliated montmorillonite nanosheet solution.

[0045] The preparation steps of aminated polyvinyl alcohol are as follows: Under stirring conditions, 50 parts by mass of a polyvinyl alcohol aqueous solution with a mass-to-volume ratio of 8 g:100 mL and 0.5 parts by mass of 1-amino-3-chloropropane hydrochloride are added, and then the temperature is raised to 85℃. 4 parts by mass of a sodium hydroxide solution with a mass-to-volume ratio of 10 g:100 mL are added, and the reaction is maintained at this temperature for 10 h. After the reaction is completed, the solution is adjusted to neutral with hydrochloric acid, cooled to room temperature, and then poured into 500 parts by mass of anhydrous ethanol. The mixture is stirred and washed thoroughly, and then vacuum filtered to obtain aminated polyvinyl alcohol. Comparative Example 1

[0046] The difference between Comparative Example 1 and Example 2 is that only 4,4'-diaminodiphenyl ether and flame-retardant diaminobenzimidazole are used as amine monomers, while the remaining steps are the same as in Example 2. Comparative Example 2

[0047] The difference between Comparative Example 2 and Example 2 is that the amine monomers used are only 4,4'-diaminodiphenyl ether, diaminobenzimidazole, and 4-aminobenzonitrile, while the other steps are the same as in Example 2. Comparative Example 3

[0048] The difference between Comparative Example 3 and Example 2 is that only 4,4'-diaminodiphenyl ether and 4-aminobenzonitrile are used as amine monomers, while the other steps are the same as in Example 2. Comparative Example 4

[0049] The difference between Comparative Example 4 and Example 2 is that no heat-insulating filler was added to the raw material components of the flame-retardant adhesive layer, while the remaining steps are the same as in Example 2. Comparative Example 5

[0050] The difference between Comparative Example 5 and Example 2 is that the heat insulation filler is made of hydroxyapatite nanowires, montmorillonite nanosheets and polyvinyl alcohol, while the other steps are the same as in Example 2. Comparative Example 6

[0051] The difference between Comparative Example 6 and Example 2 is that the heating and curing steps include: first heating to 60°C and holding for 5 hours, then heating to 150°C at 40°C / min and holding for 2 hours, and the remaining steps are the same as in Example 2. Example of effect

[0052] The flame-retardant and heat-insulating aluminum foil reinforced composite materials prepared in Examples 1-3 and Comparative Examples 1-6 were tested according to the method disclosed in JC / T2028-2018 "Composite facing materials for mineral wool insulation products". Before the test, the flame-retardant and heat-insulating aluminum foil reinforced composite materials were placed in deionized water and immersed for 15 minutes at a depth of 20 mm from the water surface. After being taken out, the surface water was wiped dry, and the materials were dried in an oven at 105°C for 20 minutes and then cooled to room temperature (25°C).

[0053] Table 1 below shows the performance test results of the flame-retardant and heat-insulating aluminum foil reinforced composite materials prepared in Examples 1-3 and Comparative Examples 1-6: Table 1

[0054] Table 1 shows that the flame-retardant and heat-insulating aluminum foil reinforced composite materials prepared in Examples 1-3 have good flame-retardant and heat-insulating properties.

[0055] The difference between Comparative Example 1 and Example 2 is that the amine monomers 4-aminobenzonitrile 4,4'-diaminodiphenyl ether and flame-retardant diaminobenzimidazole were not used, resulting in weaker flame retardancy and heat insulation properties of the flame-retardant and heat-insulating aluminum foil reinforced composite material.

[0056] The difference between Comparative Example 2 and Example 2 is that the amine monomer used is diaminobenzimidazole instead of flame-retardant diaminobenzimidazole, resulting in a flame-retardant and heat-insulating aluminum foil reinforced composite material with weaker flame retardancy and heat insulation properties.

[0057] The difference between Comparative Example 3 and Example 2 is that the flame-retardant diaminobenzimidazole was not used as the amine monomer, resulting in a weaker flame-retardant and heat-insulating aluminum foil reinforced composite material.

[0058] The difference between Comparative Example 4 and Example 2 is that no heat-insulating filler was added to the raw material components of the flame-retardant adhesive layer, resulting in a weaker flame-retardant and heat-insulating aluminum foil reinforced composite material.

[0059] The difference between Comparative Example 5 and Example 2 is that the heat insulation filler is polyvinyl alcohol instead of aminopolyvinyl alcohol. The heat insulation filler partially agglomerates, resulting in a weaker flame retardant and heat insulation performance of the flame-retardant and heat-insulating aluminum foil reinforced composite material.

[0060] The difference between Comparative Example 6 and Example 2 is that the heating and curing step was not performed at 380°C, resulting in a weaker flame retardant and heat insulation composite material with reinforced aluminum foil.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flame-retardant and heat-insulating aluminum foil reinforced composite material, characterized in that, From bottom to top, it includes an aluminum foil layer, a reinforcing mesh, kraft paper, and a flame-retardant adhesive layer for bonding the aluminum foil layer to the reinforcing mesh and the reinforcing mesh to the kraft paper.

2. The flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 1, characterized in that, The raw material components of the flame-retardant adhesive layer include dianhydride monomers, amine monomers, and heat-insulating fillers.

3. The flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 2, characterized in that, The amine monomers include 4,4'-diaminodiphenyl ether, flame-retardant diaminobenzimidazole, and 4-aminobenzonitrile.

4. The flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 3, characterized in that, The flame-retardant diaminobenzimidazole is obtained by reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with 2-(4-aminophenyl)-5-aminobenzimidazole.

5. The flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 2, characterized in that, The heat-insulating filler is made of hydroxyapatite nanowires, montmorillonite nanosheets, and amino-modified polyvinyl alcohol.

6. A method for preparing a flame-retardant and heat-insulating aluminum foil reinforced composite material as described in any one of claims 1 to 5, characterized in that, step include: (1) Coat one side of the kraft paper with a heat-insulating adhesive layer, then lay fiberglass cloth on the high-temperature resistant adhesive layer and heat-cur it to obtain a kraft paper / fiberglass cloth composite layer; (2) A heat-insulating adhesive layer is coated on the outside of the fiberglass cloth of the kraft paper-fiberglass cloth composite material, and then aluminum foil is laid on the high-temperature resistant adhesive layer and then heated and cured to obtain a flame-retardant heat-insulating aluminum foil reinforced composite material.

7. The method for preparing the flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 6, characterized in that, The preparation method of the heat-insulating adhesive layer is as follows: Under nitrogen protection, the heat-insulating filler is uniformly dispersed in N-methylpyrrolidone, then an amine monomer is added and stirred for 60-90 min, followed by the addition of dianhydride monomer, and stirring is continued at room temperature for 5-7 h to obtain the heat-insulating adhesive layer; the molar ratio of amine monomer to dianhydride monomer is 1:(1.2-1.5); the amount of heat-insulating filler added is 0.03-0.1 times the total mass of dianhydride monomer and amine monomer.

8. The method for preparing the flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 7, characterized in that, The molar ratio of 4,4'-diaminodiphenyl ether, flame-retardant diaminobenzimidazole, and 4-aminobenzonitrile in the amine monomer is (3~4):(1~2):(1~2); the preparation steps of the flame-retardant diaminobenzimidazole are as follows: under nitrogen protection, 5 parts by mass of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are dissolved in 12~15 parts by mass of acetonitrile, and then 3~3.2 parts by mass of sulfonyl chloride are added dropwise. Then the mixture is heated under reflux for 55~65 min and cooled to room temperature to obtain solution A; 5.7~6 parts by mass of 2-(4-aminophenyl)-5-aminobenzimidazole and 5.1~5.3 parts by mass of triethylamine are dissolved in acetonitrile and stirred thoroughly. Solution A is then added dropwise, and the mixture is stirred at 75~85℃ for 9~11 h. After cooling to room temperature, the mixture is filtered, washed, and dried to obtain flame-retardant diaminobenzimidazole.

9. The method for preparing the flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 7, characterized in that, The preparation steps of the heat-insulating filler are as follows: 5 parts by mass of aminated polyvinyl alcohol are added to 48-52 parts by mass of deionized water, heated in a water bath at 88-92℃ for 3-5 hours, then 54-56 parts by mass of the exfoliated montmorillonite nanosheet solution are added and stirred to disperse evenly. Then 0.1-0.3 parts by mass of hydroxyapatite nanowires are added and stirred for 1-3 hours. The mixture is then poured into a mold, directionally frozen for 18-22 minutes, and freeze-dried for 71-73 hours to obtain the heat-insulating filler. The preparation steps of the exfoliated montmorillonite nanosheet solution are as follows: 4-6 parts by mass of montmorillonite nanosheets are added to 50 parts by mass of deionized water and stirred rapidly for 23-25 ​​hours to obtain the exfoliated montmorillonite nanosheet solution.

10. The method for preparing the flame-retardant and heat-insulating aluminum foil reinforced composite material according to claim 6, characterized in that, The heating and curing steps include: first heating to 60℃ and holding for 4-6 hours, then heating to 120-180℃ at 35-45℃ / min and holding for 1-2 hours, and finally heating to 370-380℃ and holding for 1-3 hours.

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