High-temperature-resistant, flame-retardant, environment-friendly putty and preparation method thereof

Abstract

The present application belongs to the technical field of high-temperature-resistant sealing and flame-retardant protective materials, and particularly relates to a high-temperature-resistant and flame-retardant environment-friendly putty and a preparation method thereof. A mixture A is prepared by vacuum kneading siloxane base material, methylphenyl silicone resin, flame-retardant filler, ceramic filler, boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramic inorganic modified compound and zirconium-titanium-cerium modified phosphosilicate aluminum heat-resistant flame-retardant inorganic modified compound. A mixture B is prepared by mixing silane crosslinking agent, coupling agent, catalyst and solvent. The two mixtures are separately stored, and are mixed and solidified when used. The obtained putty has the properties of high-temperature resistance, flame retardation, environmental protection, stable adhesion and ceramic protective performance.

Description

Technical Field

[0001] This invention belongs to the technical field of high-temperature resistant sealing and flame-retardant protective materials, specifically relating to a high-temperature resistant, flame-retardant, and environmentally friendly putty and its preparation method. Background Technology

[0002] High-temperature resistant, flame-retardant, and environmentally friendly putty is commonly used in aerospace thermal protection structures, gaps in high-temperature equipment, surface defects in metal components, and large-area repairs. Its function extends beyond simply filling surfaces and sealing gaps; it must maintain stable morphology, strength, and adhesion under conditions of high-temperature airflow, thermal shock, localized high pressure, and complex service environments. According to the specifications, high-temperature amorphous filler putty, as a special functional material specifically designed for extreme aerospace conditions, focuses on aerodynamic shaping and sealing of thermal protection systems. It fills gaps in skin joints and recesses in countersunk fasteners, creating a smooth surface that meets aerodynamic requirements. As a key component of thermal protection structures, it seals designed gaps between materials to prevent the intrusion of high-temperature airflow and protect internal components from thermal damage. Therefore, in addition to good workability, this type of putty must also possess room-temperature curing capability, rapid curing capability upon heating, high hardness after curing, strong adhesion to substrates such as aluminum alloys, and low thermal weight loss in high-temperature air.

[0003] Existing high-temperature resistant putties mostly use organosilicon resin or silicone rubber as the base film-forming and curing system, combined with inorganic fillers such as fumed silica, mica powder, wollastonite powder, hollow glass microspheres, and rutile titanium dioxide to improve thixotropy, filling capacity, thermal insulation, and heat resistance. They also incorporate flame-retardant ceramicizing components such as aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, zinc borate, and borosilicate glass powder to improve flame retardancy and residual skeleton strength at high temperatures. However, the inorganic fillers in conventional formulations are usually physically mixed, and after heating, there is a lack of continuous ceramicizing synergistic reaction between the fillers, easily leading to problems such as filler agglomeration, insufficient interfacial bonding, inadequate pore sealing, and loose structure after firing. Under high-temperature air or thermal shock conditions, the voids created by the decomposition of organic components cannot be effectively filled, and the residual layer is prone to shrinkage, cracking, powdering, or detachment from the substrate interface. This makes it difficult for the putty to maintain a smooth surface and sealing protection function, failing to fully meet the environmental adaptability and reliability requirements for aerospace thermal protection gap filling, large-area repair, and critical protective components.

[0004] Furthermore, existing flame-retardant and high-temperature resistant putties often rely on adding large amounts of inorganic flame-retardant fillers or glass powder to improve heat resistance and flame retardancy. While this can improve high-temperature residue, it easily leads to increased paste viscosity, difficulty in application and scraping, decreased uniformity after mixing, shortened pot life, and increased brittleness of the cured layer, making it difficult to balance excellent processability and high-temperature protection performance. Some traditional systems may also use flame-retardant additives, catalysts, or volatile components with insufficient environmental friendliness, which is detrimental to use in closed assembly environments and for high-reliability components. Therefore, there is an urgent need for a high-temperature resistant, flame-retardant, and environmentally friendly putty that can be stored separately and stably, mixed evenly during use, and cured at room temperature and rapidly by heating. This putty can form a more stable silicon-oxygen crosslinking network in an organosilicon matrix. Furthermore, it can be modified by using boron, nitrogen, and phosphorus synergistic layered precursors to derive silicon-aluminum-magnesium ceramicized inorganic modified compounds and zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compounds. These compounds can then be used in conjunction with conventional flame-retardant fillers and ceramicized fillers to construct a dense high-temperature protective layer. This would improve the existing putty's insufficient heat resistance, weight loss, flame retardancy, heat insulation, crack resistance, sealing, and adhesion retention capabilities. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-temperature resistant, flame-retardant, and environmentally friendly putty and its preparation method.

[0006] In a first aspect, the present invention provides a method for preparing a high-temperature resistant, flame-retardant, and environmentally friendly putty, comprising the following steps: S1. By weight, mix 28.0-42.0 parts of hydroxyl-terminated polydimethylsiloxane, 8.0-18.0 parts of methylphenyl silicone resin, and 3.0-8.0 parts of dimethyl silicone oil to obtain a siloxane-based material; add 5.0-12.0 parts of fumed silica, 8.0-18.0 parts of mica powder, 6.0-14.0 parts of wollastonite powder, 3.0-8.0 parts of hollow glass microspheres, 5.0-12.0 parts of aluminum hydroxide, 4.0-10.0 parts of magnesium hydroxide, 5.0-12.0 parts of ammonium polyphosphate, 2.0-6.0 parts of zinc borate, 3.0-8.0 parts of borosilicate glass powder, and 1.0-4.0 parts of rutile titanium dioxide. Mixture A is prepared by vacuum kneading 2.0-6.0 parts of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound, 1.0-5.0 parts of zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound, and 0.1-0.5 parts of polyether-modified siloxane defoamer at 35-45℃. Mixture B is prepared by mixing 4.0-10.0 parts of methyltrimethoxysilane, 3.0-8.0 parts of tetraethyl orthosilicate, 1.0-4.0 parts of vinyltrimethoxysilane, 0.5-2.0 parts of γ-aminopropyltriethoxysilane, 0.2-1.0 parts of diisopropoxydiacetylacetonate, 0.1-0.8 parts of bismuth isooctanoate, and 0-4.0 parts of anhydrous ethanol. S2. Store mixture A and mixture B separately; when using, mix mixture A and mixture B together and stir at 25-35℃.

[0007] In this invention, during the preparation of high-temperature resistant, flame-retardant, and environmentally friendly putty, hydroxyl-terminated polydimethylsiloxane, methylphenyl silicone resin, and dimethyl silicone oil are first mixed to form a siloxane-based material. The hydroxyl-terminated polydimethylsiloxane provides condensable hydroxyl groups and a flexible silicone backbone; the methylphenyl silicone resin improves the system's heat resistance and high-temperature residual skeleton stability; and the dimethyl silicone oil improves the paste's wettability and application rheology. Fumed silica forms a reinforcing and thixotropic network within the siloxane-based material. Mica powder, wollastonite powder, hollow glass microspheres, borosilicate glass powder, and rutile titanium dioxide collectively provide sheet-like shielding, needle-like support, lightweight insulation, glass phase sealing, and heat-resistant filling. Aluminum hydroxide and magnesium hydroxide dehydrate and absorb heat upon heating, diluting combustible decomposition products. Ammonium polyphosphate forms phosphate-related components upon heating and promotes the formation of inorganic residues. Zinc borate and borosilicate glass powder form a boron-containing glass phase at high temperatures and fill cracks. Boron, nitrogen, and phosphorus synergistic layered precursor-derived silicon, aluminum, and magnesium ceramicized inorganic modified compounds provide layered shielding, boron and phosphorus inorganic bonding, and hexagonal boron nitride nanosheet thermal barrier effects. Zirconium, titanium, and cerium modified phosphorus silicate heat-resistant and flame-retardant inorganic modified compounds improve the shrinkage resistance, oxidation resistance, and heat resistance stability of the high-temperature inorganic framework. Methyltrimethoxysilane, tetraethyl orthosilicate, vinyltrimethoxysilane, γ-aminopropyltriethoxysilane, diisopropoxydiacetylacetonate, bismuth isooctanoate, and anhydrous ethanol form mixture B. During use, mixture B is mixed with mixture A. Methyltrimethoxysilane, tetraethyl orthosilicate, and vinyltrimethoxysilane hydrolyze with the presence of water to generate silanol structures, which then condense with hydroxyl-terminated polydimethylsiloxane, methylphenyl silicone resin, and the hydroxyl groups on the surface of inorganic fillers, forming a silicon-oxygen crosslinking network. γ-aminopropyltriethoxysilane improves the interfacial bonding between the organosilicon matrix, inorganic fillers, and substrate through hydrolysis, condensation, and amino effects. Diisopropoxydiacetylacetonate and bismuth isooctanoate promote the condensation curing reaction. The resulting high-temperature resistant, flame-retardant, and environmentally friendly putty, upon heating, forms a residual organosilicon phase, a phosphate-bound phase, a borosilicate glass phase, and a multi-element inorganic ceramicized framework, thereby achieving high-temperature resistance, flame retardancy, sealing, and adhesive protection properties.

[0008] According to a preferred embodiment of the present invention, in step S1, the vacuum kneading time is 60-120 min.

[0009] According to a preferred embodiment of the present invention, in step S2, the weight ratio of mixture A to mixture B is 100:(8-15).

[0010] According to a preferred embodiment of the present invention, the preparation method of the boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound includes: A1. By weight, add 18.0-22.0 parts of magnesium nitrate hexahydrate and 8.0-12.0 parts of aluminum nitrate nonahydrate to 120.0-180.0 parts of deionized water, and stir at 25-35℃ to obtain a magnesium-aluminum mixed salt solution; add 1.5-3.5 parts of sodium metasilicate pentahydrate and 10.0-18.0 parts of sodium hydroxide to 60.0-100.0 parts of deionized water to obtain a silicon-containing alkaline precipitate; under a nitrogen atmosphere... Next, the silicon-containing alkaline precipitate is added to a magnesium-aluminum mixed salt solution, the pH is adjusted to 9.2-10.0, and the solution is aged at 55-70℃ to obtain a silicon-containing magnesium-aluminum layered hydroxide precursor slurry; 8.0-19.0 parts of disodium hydrogen phosphate dodecahydrate and 1.0-4.0 parts of boric acid are added to the silicon-containing magnesium-aluminum layered hydroxide precursor slurry, and the solution is reacted at 70-85℃. After filtration and washing, a boron-phosphorus modified magnesium-aluminum-silicon layered precursor is obtained. A2. Add boron-phosphorus modified magnesium-aluminum-silicon layered precursor to a mixture of 80.0-140.0 parts deionized water and 30.0-60.0 parts anhydrous ethanol, add 1.0-4.0 parts hexagonal boron nitride nanosheets, disperse ultrasonically, and then transfer to a hydrothermal reactor. React at 110-140℃ to obtain a boron-nitrogen-phosphorus synergistic layered precursor composite slurry. Filter, wash, dry, and grind the boron-nitrogen-phosphorus synergistic layered precursor composite slurry, calcine it at 420-520℃ under a nitrogen atmosphere, and then cool it.

[0011] In this invention, during the preparation of the boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound, magnesium nitrate hexahydrate and aluminum nitrate nonahydrate are dissolved in deionized water to form a magnesium-aluminum mixed salt solution, while sodium metasilicate pentahydrate and sodium hydroxide are dissolved in deionized water to form a silicon-containing alkaline precipitate. Under a nitrogen atmosphere, the silicon-containing alkaline precipitate is added to the magnesium-aluminum mixed salt solution. Sodium hydroxide provides an alkaline environment, causing magnesium and aluminum ions to gradually hydrolyze and co-precipitate, forming a silicon-containing magnesium-aluminum layered hydroxide precursor slurry. Sodium metasilicate pentahydrate provides silicate components in the aqueous phase. These silicate components enter the magnesium-aluminum layered hydroxide precursor system through co-deposition, surface adsorption, hydroxyl interaction, and local silicon-oxygen bonding, giving the resulting precursor a silicon-containing characteristic. The nitrogen atmosphere reduces the entry of carbon dioxide from the air into the reaction system, decreasing the competition of carbonate ions for interlayer sites and surface alkaline sites. Subsequently, disodium hydrogen phosphate dodecahydrate and boric acid were added to the silicon-magnesium-aluminum layered hydroxide precursor slurry. Disodium hydrogen phosphate dodecahydrate provided the hydrogen phosphate component, while boric acid formed boron hydroxyl structures and partially converted into borate components in the reaction system. The hydrogen phosphate and borate components interacted with the magnesium-aluminum hydroxyl plates, surface hydroxyl groups, and interlayer anion sites in the silicon-magnesium-aluminum layered hydroxide precursor slurry through anion exchange, surface deposition, coordination bonding, and hydrogen bonding, forming a boron-phosphorus modified magnesium-aluminum-silicon layered precursor. The boron-phosphorus modified magnesium-aluminum-silicon layered precursor was ultrasonically dispersed and hydrothermally treated with hexagonal boron nitride nanosheets in a mixture of deionized water and anhydrous ethanol. The hexagonal boron nitride nanosheets were mainly distributed on the precursor surface and in the interparticle spaces through layer dispersion, interfacial adsorption, and interparticle overlap, forming a boron-nitrogen-phosphorus synergistic layered precursor composite slurry. After subsequent filtration, washing, drying, grinding, and calcination in a nitrogen atmosphere, the layered hydroxide precursor undergoes dehydration, dehydroxylation, and structural rearrangement, transforming into a silicon-aluminum-magnesium-containing layered precursor-derived inorganic phase. The phosphate and borate components form a heat-resistant inorganic bonded phase, while the hexagonal boron nitride nanosheets maintain the layered shielding and thermal barrier functions, ultimately yielding a boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound.

[0012] According to a preferred embodiment of the present invention, in step A1, the stirring time at 25-35°C is 30-60 min; the aging time at 55-70°C is 4-8 h; and the reaction time at 70-85°C is 3-6 h.

[0013] According to a preferred embodiment of the present invention, in step A2, the ultrasonic dispersion time is 20-40 min; the reaction time at 110-140℃ is 6-10 h; and the calcination time at 420-520℃ is 1.5-3.0 h.

[0014] According to a preferred embodiment of the present invention, the preparation method of the zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound includes: B1. By weight, mix 10.0-18.0 parts of tetraethyl orthosilicate, 40.0-70.0 parts of anhydrous ethanol, 10.0-18.0 parts of deionized water, and 0.2-0.6 parts of nitric acid, and stir at 25-35°C to obtain an acidic silica sol; add 0.8-2.0 parts of tetrabutyl titanate to the acidic silica sol and continue stirring to obtain a titanium-containing acidic silica sol; add 8.0-14.0 parts of aluminum isopropoxide and 40.0-80.0 parts of anhydrous... Ethanol is mixed and added to a titanium-containing acidic silica sol. The mixture is stirred at 50-65°C, and 3.0-6.0 parts of ammonium dihydrogen phosphate and 8.0-15.0 parts of deionized water are added to obtain a titanium-containing aluminum-phosphorus silica composite sol. 1.0-2.5 parts of zirconium oxynitrate hydrate and 0.3-1.2 parts of cerium nitrate hexahydrate are added to 30.0-60.0 parts of deionized water, and 0.5-1.5 parts of citric acid are added. The mixture is stirred at 45-60°C to obtain a zirconium-cerium composite metal salt solution. B2. Mix the titanium-containing phosphorus aluminum silicate composite sol and the zirconium-cerium composite metal salt solution, stir at 45-60℃, adjust the pH to 5.5-6.5 with ammonia water to obtain zirconium-titanium-cerium modified phosphorus aluminum silicate gel; dry and crush the zirconium-titanium-cerium modified phosphorus aluminum silicate gel, calcine it at 580-680℃ in air atmosphere, and then pulverize it.

[0015] In this invention, during the preparation of the zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound, after mixing tetraethyl orthosilicate, anhydrous ethanol, deionized water, and nitric acid, tetraethyl orthosilicate undergoes controlled hydrolysis in an acidic alcohol-water system to generate silanol structures. These silanol structures further condense to form an acidic silica sol. After adding tetrabutyl titanate to the acidic silica sol, the alkoxy groups in tetrabutyl titanate gradually hydrolyze to form titanium hydroxyl structures. These titanium hydroxyl structures condense with the silanol structures to form a titanium-containing acidic silica sol, resulting in a relatively uniform dispersion of the titanium component within the silica sol network. Aluminum isopropoxide and anhydrous ethanol are mixed and added to a titanium-containing acidic silica sol. Under the action of water and acidic media, aluminum isopropoxide gradually hydrolyzes to generate aluminum hydroxyl structures. These aluminum hydroxyl structures condense and complex with silanol and titanium hydroxyl structures, forming a composite sol framework of aluminum, titanium, and silicon. After adding ammonium dihydrogen phosphate and deionized water, ammonium dihydrogen phosphate provides phosphate-related structures. These phosphate-related structures coordinate, deposit, and condense with the aluminum hydroxyl, titanium hydroxyl, and silanol structures, yielding a titanium-containing aluminum-phosphorus-silicon composite sol. Zirconium oxynitrate hydrate and cerium nitrate hexahydrate, dissolved in deionized water, provide zirconium and cerium components. Citric acid complexes with the zirconium and cerium components, reducing uneven precipitation caused by excessively rapid local hydrolysis, forming a zirconium-cerium composite metal salt solution. After mixing a titanium-phosphorus-aluminum-silicon composite sol and a zirconium-cerium composite metal salt solution, the pH was adjusted with ammonia. The aluminum, titanium, zirconium, and cerium components gradually hydrolyzed, deposited, and gelled. Phosphate-related structures combined with the hydroxyl structures related to aluminum, titanium, zirconium, and cerium, while the silanol structures continued to condense, forming a zirconium-titanium-cerium modified aluminum phosphosilicate gel. After drying, crushing, and calcination in air, residual organic groups, nitrates, and volatile components gradually decomposed and escaped. The gel skeleton underwent inorganicization, composite formation, and densification, forming a composite inorganic network containing zirconium, titanium, cerium, phosphorus, silicon, and aluminum, thus yielding a heat-resistant and flame-retardant inorganic modified compound of zirconium-titanium-cerium modified aluminum phosphosilicate.

[0016] According to a preferred embodiment of the present invention, in step B1, the stirring time at 25-35°C is 40-80 min; and the stirring time at 45-60°C is 30-60 min.

[0017] According to a preferred embodiment of the present invention, in step B2, the calcination time at 580-680°C is 2-4 hours.

[0018] In a second aspect, the present invention provides a high-temperature resistant, flame-retardant, and environmentally friendly putty prepared according to the preparation method of the high-temperature resistant, flame-retardant, and environmentally friendly putty described above.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention uses hydroxyl-terminated polydimethylsiloxane, methylphenyl silicone resin and dimethyl silicone oil to form a siloxane material, and uses it in combination with methyltrimethoxysilane, tetraethyl orthosilicate, vinyltrimethoxysilane, γ-aminopropyltriethoxysilane, diisopropoxydiacetylacetonate titanium, bismuth isooctanoate and anhydrous ethanol, so that mixture A and mixture B can be stored separately and then mixed and cured before use, reducing the risk of premature reaction and storage instability. The resulting high-temperature resistant, flame-retardant and environmentally friendly putty has good paste uniformity, scraping and filling properties, and can form a stable siloxane cross-linked structure after curing, which is beneficial to improving the adhesion and retention ability of the substrate surface and the overall stability of the repaired part; (2) This invention constructs a flame-retardant and heat-insulating filling system using fumed silica, mica powder, wollastonite powder, hollow glass microspheres, aluminum hydroxide, magnesium hydroxide, ammonium polyphosphate, zinc borate, borosilicate glass powder, and rutile titanium dioxide. Fumed silica improves reinforcement and thixotropic properties, mica powder provides a layered shielding effect, wollastonite powder provides skeletal support, hollow glass microspheres reduce heat conduction, aluminum hydroxide and magnesium hydroxide absorb heat and suppress flame after heating, ammonium polyphosphate promotes the formation of inorganic residues, zinc borate and borosilicate glass powder are conducive to the formation of a glassy closed structure, and rutile titanium dioxide improves the heat-resistant filling stability, thereby improving the problems of shrinkage, powdering, cracking, and insufficient heat insulation at high temperatures. (3) This invention introduces boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compounds and zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compounds, enabling the high-temperature resistant and flame-retardant environmentally friendly putty to form a more stable multi-element inorganic ceramicized framework after heating. The boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compounds provide layered shielding, boron-phosphorus inorganic bonding, and hexagonal boron nitride nanosheet thermal barrier effects; the zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compounds improve the oxidation resistance, shrinkage resistance, and heat resistance stability of the residual inorganic layer. The two compounds work synergistically with borosilicate glass powder, ammonium polyphosphate, and zinc borate, so that the resulting high-temperature resistant and flame-retardant environmentally friendly putty has high-temperature resistance, flame retardancy, sealing properties, and adhesion retention. Detailed Implementation

[0020] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0021] Example 1: This example provides a method for preparing a high-temperature resistant, flame-retardant, and environmentally friendly putty, the steps of which include: S1. Add 35.0g of hydroxyl-terminated polydimethylsiloxane, 13.0g of methylphenyl silicone resin and 5.5g of dimethyl silicone oil to a vacuum kneader and premix at 25℃ for 20min to obtain a siloxane material. Then, add the following to the siloxane material in sequence: 8.5g of fumed silica, 13.0g of mica powder, 10.0g of wollastonite powder, 5.5g of hollow glass microspheres, 8.5g of aluminum hydroxide, 7.0g of magnesium hydroxide, 8.5g of ammonium polyphosphate, 4.0g of zinc borate, 5.5g of borosilicate glass powder, 2.5g of rutile titanium dioxide, 4.0g of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modification compound, and 3.0g of zirconium-titanium-cerium modified phosphorus-silicon. A mixture of heat-resistant and flame-retardant inorganic modified aluminum oxide compound and 0.3g of polyether-modified siloxane defoamer was prepared by vacuuming the system to -0.090MPa at 40℃ for 90 minutes until a uniform paste was formed without visible powder agglomerates, resulting in mixture A. 7.0g of methyltrimethoxysilane, 5.5g of tetraethyl orthosilicate, 2.5g of vinyltrimethoxysilane, 1.25g of γ-aminopropyltriethoxysilane, 0.6g of diisopropoxydiacetylacetonate, 0.45g of bismuth isooctanoate, and 2.0g of anhydrous ethanol were added to a dry, sealed container and stirred at 25℃ for 30 minutes until a uniform, transparent liquid was formed, resulting in mixture B.

[0022] S2. Store mixture A in a sealed container and mixture B in a dry sealed container. When using, weigh mixture A and mixture B according to the weight ratio of 100:11.5. Add mixture B to mixture A and stir at 30°C for 5 minutes until the paste is uniform in color, without lumps or obvious bubbles, to obtain a high-temperature resistant, flame-retardant, and environmentally friendly putty.

[0023] Preparation of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compounds: A1. Weigh 20.0g of magnesium nitrate hexahydrate and 10.0g of aluminum nitrate nonahydrate, and add them to a glass reactor containing 150.0g of deionized water. The glass reactor is equipped with a mechanical stirrer, thermometer, and pH meter. Stir at 300r / min for 45min at 30℃ until the magnesium nitrate hexahydrate and aluminum nitrate nonahydrate are completely dissolved, resulting in a clear and transparent magnesium-aluminum mixed salt solution. Separately, take 2.5g of sodium metasilicate pentahydrate and 14.0g of sodium hydroxide, and add them to a beaker containing 80.0g of deionized water. Stir at 300r / min for 30min at 25℃ until the sodium metasilicate pentahydrate and sodium hydroxide are completely dissolved, resulting in a silicon-containing alkaline precipitate. Purge the glass reactor with nitrogen gas for 10min to replace the air, and maintain the nitrogen atmosphere. Stirring was used to slowly add the silicon-containing alkaline precipitate to the magnesium-aluminum mixed salt solution. During the addition process, the system temperature was controlled at 30℃, and the pH of the system was controlled at 9.6 by adding a small amount of sodium hydroxide aqueous solution. After the addition was completed, the temperature was raised to 62.5℃, and the mixture was stirred and aged at 300 r / min for 6 h at 62.5℃ to obtain a silicon-containing magnesium-aluminum layered hydroxide precursor slurry. 13.5 g of disodium hydrogen phosphate dodecahydrate and 2.5 g of boric acid were added to the silicon-containing magnesium-aluminum layered hydroxide precursor slurry, and the mixture was stirred and reacted at 300 r / min for 4.5 h at 77.5℃. After the reaction was completed, the mixture was filtered by vacuum filtration. The obtained filter cake was washed three times with deionized water, each time using 100.0 g of deionized water. After washing, the boron-phosphorus modified magnesium-aluminum-silicon layered precursor was obtained.

[0024] A2. The boron-phosphorus modified magnesium-aluminum-silicon layered precursor obtained in A1 was added to a reaction vessel containing 110.0 g of deionized water and 45.0 g of anhydrous ethanol. The mixture was stirred at 300 r / min for 20 min at 25 °C to ensure uniform dispersion. 2.5 g of hexagonal boron nitride nanosheets were added, and the mixture was ultrasonically dispersed at 500 W for 30 min, with the system temperature controlled not to exceed 35 °C during the ultrasonic process, to obtain a uniform dispersion. The uniform dispersion was transferred to a polytetrafluoroethylene-lined hydrothermal reactor, sealed, and placed in a forced-air drying oven. The reaction was carried out at 125 °C for 8 h, followed by natural cooling to room temperature. A boron-nitrogen-phosphorus synergistic layered precursor composite slurry was obtained. The boron-nitrogen-phosphorus synergistic layered precursor composite slurry was filtered, and the resulting filter cake was washed three times with deionized water and once with anhydrous ethanol. The washed filter cake was placed in a vacuum drying oven and dried at 90°C for 12 hours. After drying, it was ground for 30 minutes to obtain a dry powder. The dry powder was placed in a tube furnace and calcined at 470°C for 2.25 hours under a nitrogen atmosphere. After calcination, it was cooled to room temperature under a nitrogen atmosphere, ground, and passed through a 200-mesh sieve to obtain a boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound.

[0025] Preparation of heat-resistant and flame-retardant inorganic modified compounds of zirconium-titanium-cerium-modified aluminum phosphosilicate: B1. Add 14.0 g of tetraethyl orthosilicate, 55.0 g of anhydrous ethanol, 14.0 g of deionized water, and 0.4 g of nitric acid to a dry glass reactor equipped with a mechanical stirrer and thermometer. Stir at 300 rpm for 60 min at 30 °C to obtain an acidic silica sol. Slowly add 1.4 g of tetrabutyl titanate to the acidic silica sol. After the addition is complete, continue stirring at 300 rpm for 30 min at 30 °C to obtain a titanium-containing acidic silica sol. Add 11.0 g of aluminum isopropoxide and 60.0 g of anhydrous ethanol to another dry beaker and stir at 300 rpm for 2 minutes at 25 °C. After 0 min, add the titanium-containing acidic silica sol, heat to 57.5℃, and stir at 300 r / min at 57.5℃ until the system is homogeneous. Then add 4.5 g of ammonium dihydrogen phosphate and 11.5 g of deionized water, and continue stirring at 300 r / min at 57.5℃ for 60 min to obtain a titanium-containing aluminum-phosphorus silica composite sol. Add 1.75 g of zirconium oxynitrate hydrate and 0.75 g of cerium nitrate hexahydrate to 45.0 g of deionized water, add 1.0 g of citric acid, and stir at 300 r / min at 52.5℃ for 45 min until a homogeneous transparent or semi-transparent solution is formed to obtain a zirconium-cerium composite metal salt solution.

[0026] B2. The titanium-phosphorus-aluminum-silicon composite sol obtained in B1 and the zirconium-cerium composite metal salt solution were added to the same reactor and stirred at 300 r / min for 60 min at 52.5℃. The pH was adjusted to 6.0 with ammonia water, and stirring was continued at 300 r / min for 60 min at 52.5℃ to obtain zirconium-titanium-cerium modified aluminum phosphosilicate gel. The zirconium-titanium-cerium modified aluminum phosphosilicate gel was placed in a forced-air drying oven and dried at 90℃ for 12 h. After drying, it was crushed into powder blocks. The powder blocks were placed in a muffle furnace and calcined at 630℃ for 3 h in an air atmosphere. After calcination, it was naturally cooled to room temperature, removed, pulverized, and passed through a 200-mesh sieve to obtain the heat-resistant and flame-retardant inorganic modified compound of zirconium-titanium-cerium modified aluminum phosphosilicate.

[0027] Example 2: The difference between this example and Example 1 is that this example provides a method for preparing a high-temperature resistant, flame-retardant, and environmentally friendly putty, the steps of which include: S1. Mix 28.0g of hydroxyl-terminated polydimethylsiloxane, 8.0g of methylphenyl silicone resin, and 3.0g of dimethyl silicone oil, and stir until homogeneous to obtain a siloxane-based material. Add 5.0g of fumed silica, 8.0g of mica powder, 6.0g of wollastonite powder, 3.0g of hollow glass microspheres, 5.0g of aluminum hydroxide, 4.0g of magnesium hydroxide, 5.0g of ammonium polyphosphate, 2.0g of zinc borate, 3.0g of borosilicate glass powder, 1.0g of rutile titanium dioxide, and 2.0g of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum to the siloxane-based material. Magnesium ceramicized inorganic modified compound, 1.0g zirconium titanium cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound, and 0.1g polyether modified siloxane defoamer were vacuum kneaded at 35℃ for 60min to obtain a uniform paste-like mixture A; 4.0g methyltrimethoxysilane, 3.0g tetraethyl orthosilicate, 1.0g vinyltrimethoxysilane, 0.5g γ-aminopropyltriethoxysilane, 0.2g diisopropoxydiacetylacetonate, 0.1g bismuth isooctanoate, and 0g anhydrous ethanol were mixed and stirred until homogeneous to obtain a transparent liquid-like mixture B; S2. Separately seal and store mixture A and mixture B. When using, mix mixture A and mixture B at a weight ratio of 100:8 and stir at 25°C until the paste is uniform to obtain a high-temperature resistant, flame-retardant, and environmentally friendly putty.

[0028] Preparation of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compounds: A1. Add 18.0g of magnesium nitrate hexahydrate and 8.0g of aluminum nitrate nonahydrate to 120.0g of deionized water and stir at 25℃ for 30min until magnesium nitrate hexahydrate and aluminum nitrate nonahydrate are completely dissolved to obtain a magnesium-aluminum mixed salt solution; add 1.5g of sodium metasilicate pentahydrate and 10.0g of sodium hydroxide to 60.0g of deionized water and stir until completely dissolved to obtain a silicon-containing alkaline precipitate; under a nitrogen atmosphere, slowly add the silicon-containing alkaline precipitate to the magnesium-aluminum mixed salt solution, control the pH of the system to 9.2, and age at 55℃ for 4h to obtain a silicon-containing magnesium-aluminum layered hydroxide precursor slurry; add 8.0g of disodium hydrogen phosphate dodecahydrate and 1.0g of boric acid to the silicon-containing magnesium-aluminum layered hydroxide precursor slurry, react at 70℃ for 3h, filter after the reaction, and wash the obtained filter cake with deionized water to obtain a boron-phosphorus modified magnesium-aluminum-silicon layered precursor; A2. The boron-phosphorus modified magnesium-aluminum-silicon layered precursor obtained in A1 was added to a mixture of 80.0 g deionized water and 30.0 g anhydrous ethanol, and 1.0 g hexagonal boron nitride nanosheets were added. After ultrasonic dispersion for 20 min, the mixture was transferred to a hydrothermal reactor and reacted at 110 °C for 6 h to obtain a boron-nitrogen-phosphorus synergistic layered precursor composite slurry. The boron-nitrogen-phosphorus synergistic layered precursor composite slurry was filtered, and the resulting filter cake was washed, dried, and ground in sequence. Under a nitrogen atmosphere, it was calcined at 420 °C for 1.5 h and cooled to room temperature to obtain a boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound.

[0029] Preparation of heat-resistant and flame-retardant inorganic modified compounds of zirconium-titanium-cerium-modified aluminum phosphosilicate: B1. Mix 10.0g tetraethyl orthosilicate, 40.0g anhydrous ethanol, 10.0g deionized water, and 0.2g nitric acid, and stir at 25℃ for 40min to obtain an acidic silica sol; add 0.8g tetrabutyl titanate to the acidic silica sol and continue stirring until the system is homogeneous to obtain a titanium-containing acidic silica sol; mix 8.0g aluminum isopropoxide and 40.0g anhydrous ethanol and add it to the titanium-containing acidic silica sol, stir at 50℃, add 3.0g ammonium dihydrogen phosphate and 8.0g deionized water, and continue mixing until homogeneous to obtain a titanium-containing aluminum-phosphorus-silicon composite sol; add 1.0g zirconium oxynitrate hydrate and 0.3g cerium nitrate hexahydrate to 30.0g deionized water, add 0.5g citric acid, and stir at 45℃ for 30min to obtain a zirconium-cerium composite metal salt solution; B2. The titanium-phosphorus-aluminum-silicon composite sol obtained in B1 and the zirconium-cerium composite metal salt solution are mixed and stirred at 45°C. The pH is adjusted to 5.5 with ammonia water to obtain zirconium-titanium-cerium modified aluminum phosphorus silicate gel. The zirconium-titanium-cerium modified aluminum phosphorus silicate gel is dried, crushed, calcined at 580°C for 2 hours in air atmosphere, and then pulverized to obtain a heat-resistant and flame-retardant inorganic modified compound of zirconium-titanium-cerium modified aluminum phosphorus silicate. Example

[0030] The difference between this embodiment and Embodiment 1 is that this embodiment provides a method for preparing a high-temperature resistant, flame-retardant, and environmentally friendly putty, the steps of which include: S1. Mix 42.0g of hydroxyl-terminated polydimethylsiloxane, 18.0g of methylphenyl silicone resin, and 8.0g of dimethyl silicone oil, and stir until homogeneous to obtain a siloxane-based material. Add 12.0g of fumed silica, 18.0g of mica powder, 14.0g of wollastonite powder, 8.0g of hollow glass microspheres, 12.0g of aluminum hydroxide, 10.0g of magnesium hydroxide, 12.0g of ammonium polyphosphate, 6.0g of zinc borate, 8.0g of borosilicate glass powder, 4.0g of rutile titanium dioxide, and 6.0g of boron-nitrogen-phosphorus synergistic layered precursor derivative to the siloxane-based material. A mixture A is prepared by vacuum kneading a silicon-aluminum-magnesium ceramicized inorganic modified compound, 5.0 g of zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound, and 0.5 g of polyether-modified siloxane defoamer at 45 °C for 120 min to obtain a uniform paste-like mixture A. A mixture B is prepared by mixing 10.0 g of methyltrimethoxysilane, 8.0 g of tetraethyl orthosilicate, 4.0 g of vinyltrimethoxysilane, 2.0 g of γ-aminopropyltriethoxysilane, 1.0 g of diisopropoxydiacetylacetonate titanium, 0.8 g of bismuth isooctanoate, and 4.0 g of anhydrous ethanol and stirring until homogeneous to obtain a transparent liquid-like mixture B. S2. Separately seal and store mixture A and mixture B. When using, mix mixture A and mixture B at a weight ratio of 100:15 and stir at 35°C until the paste is uniform to obtain a high-temperature resistant, flame-retardant, and environmentally friendly putty.

[0031] Preparation of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compounds: A1. Add 22.0g of magnesium nitrate hexahydrate and 12.0g of aluminum nitrate nonahydrate to 180.0g of deionized water and stir at 35℃ for 60min until magnesium nitrate hexahydrate and aluminum nitrate nonahydrate are completely dissolved to obtain a magnesium-aluminum mixed salt solution; add 3.5g of sodium metasilicate pentahydrate and 18.0g of sodium hydroxide to 100.0g of deionized water and stir until completely dissolved to obtain a silicon-containing alkaline precipitate; under a nitrogen atmosphere, slowly add the silicon-containing alkaline precipitate to the magnesium-aluminum mixed salt solution, control the pH of the system to 10.0, and age at 70℃ for 8h to obtain a silicon-containing magnesium-aluminum layered hydroxide precursor slurry; add 19.0g of disodium hydrogen phosphate dodecahydrate and 4.0g of boric acid to the silicon-containing magnesium-aluminum layered hydroxide precursor slurry, react at 85℃ for 6h, filter after the reaction, and wash the obtained filter cake with deionized water to obtain a boron-phosphorus modified magnesium-aluminum-silicon layered precursor; A2. The boron-phosphorus modified magnesium-aluminum-silicon layered precursor obtained in A1 was added to a mixture of 140.0 g of deionized water and 60.0 g of anhydrous ethanol, and 4.0 g of hexagonal boron nitride nanosheets were added. After ultrasonic dispersion for 40 min, the mixture was transferred to a hydrothermal reactor and reacted at 140 °C for 10 h to obtain a boron-nitrogen-phosphorus synergistic layered precursor composite slurry. The boron-nitrogen-phosphorus synergistic layered precursor composite slurry was filtered, and the resulting filter cake was washed, dried, and ground in sequence. It was then calcined at 520 °C for 3.0 h under a nitrogen atmosphere and cooled to room temperature to obtain a boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound.

[0032] Preparation of heat-resistant and flame-retardant inorganic modified compounds of zirconium-titanium-cerium-modified aluminum phosphosilicate: B1. Mix 18.0g tetraethyl orthosilicate, 70.0g anhydrous ethanol, 18.0g deionized water, and 0.6g nitric acid, and stir at 35℃ for 80min to obtain an acidic silica sol; add 2.0g tetrabutyl titanate to the acidic silica sol and continue stirring until the system is homogeneous to obtain a titanium-containing acidic silica sol; mix 14.0g aluminum isopropoxide and 80.0g anhydrous ethanol and add it to the titanium-containing acidic silica sol, stir at 65℃, add 6.0g ammonium dihydrogen phosphate and 15.0g deionized water, and continue mixing until homogeneous to obtain a titanium-containing aluminum-phosphorus-silicon composite sol; add 2.5g zirconium oxynitrate hydrate and 1.2g cerium nitrate hexahydrate to 60.0g deionized water, add 1.5g citric acid, and stir at 60℃ for 60min to obtain a zirconium-cerium composite metal salt solution; B2. The titanium-phosphorus-aluminum-silicon composite sol obtained in B1 and the zirconium-cerium composite metal salt solution are mixed and stirred at 60°C. The pH is adjusted to 6.5 with ammonia water to obtain zirconium-titanium-cerium modified aluminum phosphorus silicate gel. The zirconium-titanium-cerium modified aluminum phosphorus silicate gel is dried, crushed, calcined at 680°C for 4 hours in air atmosphere, and then pulverized to obtain a heat-resistant and flame-retardant inorganic modified compound of zirconium-titanium-cerium modified aluminum phosphorus silicate.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that, when preparing mixture A, 4.0g of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modification compound was not added, and the borosilicate glass powder was adjusted from 5.5g to 9.5g, while the rest was the same as in Example 1.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is that, when preparing mixture A, 3.0g of zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modifying compound is not added, and the borosilicate glass powder is adjusted from 5.5g to 8.5g, while the rest is the same as in Example 1.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is that, when preparing mixture A, 4.0g of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound and 3.0g of zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound are not added, and the borosilicate glass powder is adjusted from 5.5g to 12.5g, while the rest is the same as in Example 1.

[0036] The performance of the high-temperature resistant, flame-retardant, and environmentally friendly putty obtained in Examples 1-3 and Comparative Examples 1-3 was tested in accordance with national and industry standard testing specifications.

[0037] The high-temperature resistant, flame-retardant, and environmentally friendly putty prepared in Examples 1, 2, and 3 and Comparative Examples 1, 2, and 3 were used as test samples. All tests were conducted at 25°C and 50% relative humidity. Except for the thermal weight loss test, each test sample was cured at 25°C for 24 hours after mixing mixture A and mixture B, and then placed at 25°C for 24 hours. During the storage condition test, mixture A and mixture B were placed in sealed containers respectively. After standing at 25°C for 7 days, the containers were opened and it was observed whether mixture A and mixture B remained in a separate storage state. Record whether there was premature mixing, premature gelation, obvious stratification, clumping, sedimentation hardening, or packaging leakage. When testing the appearance of mixture A, place mixture A on a clean glass plate and spread it into a thin layer with a thickness of 2 mm using a scraper. Visually inspect its color, paste continuity, lumps, hard particles, and visible impurities under natural light, and record whether it is a white paste, without lumps, and without visible impurities. When testing the appearance of mixture B, pour mixture B into a transparent glass tube, control the liquid column height to 50 mm, and observe its transparency, fluidity, precipitation, flocculent matter and turbidity under natural light, and record whether it is a transparent liquid. When testing the state of the putty mixture, samples were weighed in Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 at a weight ratio of 100:11.5 for mixture A and mixture B, in Example 2 at a weight ratio of 100:8 for mixture A and mixture B, and in Example 3 at a weight ratio of 100:15 for mixture A and mixture B. Mixture B was added to mixture A and stirred at 30°C for 5 minutes. After stirring, the mixture was applied to the surface of an aluminum alloy plate with a scraper. The coating thickness was controlled to be 1 mm. The color, uniformity, lumps, powder agglomeration and obvious bubbles were observed. It was recorded whether the mixture was white paste, uniform and without lumps. When testing the working period of the putty, the starting time is the moment when mixture B is added to mixture A and stirring begins. The mixed putty is left to stand at 25℃ and 50% relative humidity. Every 1 minute, a sample is taken with a scraper and scraped onto the surface of the aluminum alloy plate. The scraping thickness is controlled at 1 mm. When the sample shows obvious stringing, clumping, rough surface, inability to be continuously smoothed or unable to form a uniform coating, the timing is stopped. The longest time that it can still be scraped and applied normally is recorded in minutes. When testing the Shore hardness of the putty after curing, the mixed putty is filled into a flat mold to make a sample with a thickness of 6mm. After curing and placement, the sample is placed on a hard horizontal platform and tested 5 times at different positions on the sample surface using a Shore hardness tester. The distance between each test position is 8mm. Each reading is recorded after the indenter stabilizes for 3 seconds. The arithmetic mean of the 5 test results is taken as the Shore hardness of the putty after curing. For the tensile and shear strength test of aluminum alloy, aluminum alloy sheet is used as the bonding substrate. The overlapping surfaces are sanded, degreased, wiped and dried in sequence. The mixed putty is evenly applied to the overlapping surfaces. The overlapping area is controlled at 12.5mm×25mm and the adhesive layer thickness is controlled at 0.25mm. After overlapping and pressing, the surface is cured and placed. Then, a tensile and shear test is carried out at 25℃ with the loading direction parallel to the overlapping surface. The maximum breaking load is recorded, and the tensile and shear strength of aluminum alloy is calculated by dividing the maximum breaking load by the overlapping area. The unit is MPa. For the high-temperature ignition weight loss rate test, the cured putty was prepared into a 5.0 g sample, and the initial mass was recorded. The sample was placed in a high-temperature resistant crucible and heated to 1200℃ in a high-temperature electric furnace under an air atmosphere and held for 30 min. After the holding period, the sample was cooled to 25℃ with the furnace. The sample was then removed and the residual mass was weighed. The high-temperature ignition weight loss rate was calculated by dividing the difference between the initial mass and the residual mass by the initial mass and then multiplying by 100%, with the unit being % (%). During the process test, the mixed putty was cured at 25℃ for 24 hours and at 80℃ for 2 hours. After curing, it was observed whether a continuous cured layer was formed. It was recorded whether there were obvious cracks, bubbling, powdering, sagging, sticky surface or failure to cure. It was also determined whether it could be cured at room temperature or cured quickly by heating.

[0038] The performance test data above are shown in Table 1.

[0039] Table 1 Performance Test Results ; ; The test results in Table 1 clearly show that Examples 1-3 effectively solved the problems of high thermal weight loss, insufficient hardness after curing, poor adhesion retention of aluminum alloys, and insufficient stability of ceramic protective layer in existing high temperature resistant flame retardant environmentally friendly putty compared to Comparative Examples 1-3.

[0040] The applicable application period for putty application in Examples 1-3 is 45-46 minutes, indicating that the simultaneous introduction of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound and zirconium-titanium-cerium modified phosphorus-aluminate heat-resistant and flame-retardant inorganic modified compound did not significantly shorten the application window and maintained good process applicability.

[0041] The Shore hardness of the putty in Examples 1-3 after curing was 84, 82, and 86, respectively, while that in Comparative Examples 1-3 was 78, 79, and 76, respectively. This indicates that the two inorganic modified compounds (boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound and zirconium-titanium-cerium modified phosphorus-aluminate heat-resistant and flame-retardant inorganic modified compound) can improve the inorganic skeleton support and overall density of the cured layer when synergistically combined with fillers such as fumed silica, mica powder, wollastonite powder, and borosilicate glass powder, thus avoiding the problem of insufficient hardness of the cured layer when only conventional borosilicate glass powder is used for compensation.

[0042] The tensile and shear strengths of the aluminum alloys in Examples 1-3 were 2.48 MPa, 2.21 MPa, and 2.63 MPa, respectively, while those in Comparative Examples 1-3 decreased to 1.86 MPa, 1.93 MPa, and 1.62 MPa, respectively. This indicates that the bonding stability between the cured layer and the aluminum alloy interface is significantly reduced when boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound, zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound, or both inorganic modified compounds are lacking.

[0043] The high-temperature ignition weight loss rates of Examples 1-3 at 1200℃ and in air were 2.18%, 2.71%, and 1.96%, respectively, while those of Comparative Examples 1-3 increased to 4.35%, 3.82%, and 5.46%, respectively. This indicates that the two inorganic modified compounds can synergistically promote the formation of the high-temperature residual layer with ammonium polyphosphate, zinc borate, borosilicate glass powder, aluminum hydroxide, and magnesium hydroxide, making the heated ceramicized layer more dense and stable, thereby reducing the high-temperature ignition weight loss.

[0044] In particular, Comparative Example 3, without the addition of the two inorganic modifying compounds, still exhibited the lowest Shore hardness of 76, the lowest aluminum alloy tensile shear strength of 1.62 MPa, and the highest thermal weight loss rate of 5.46%, even with the borosilicate glass powder increased to 12.5 g. This indicates that simply adding conventional glass powder cannot replace the layered shielding, thermal barrier, anti-shrinkage, and multi-element inorganic framework stabilizing effects of the two inorganic modifying compounds.

[0045] Therefore, this invention, through the synergistic introduction of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compounds and zirconium-titanium-cerium modified phosphorus-aluminate aluminum phosphate heat-resistant and flame-retardant inorganic modified compounds, significantly improves the curing strength, bonding strength, and high-temperature thermal stability of high-temperature flame-retardant environmentally friendly putty without affecting the separate storage of mixture A and mixture B, the uniform white paste without lumps after mixing, and the processability of room temperature curing and rapid heating curing. It can better meet the comprehensive requirements of aerospace thermal protection gap filling, large-area repair, and high-temperature sealing protection for heat resistance, flame retardancy, crack resistance, and adhesion retention performance.

Claims

1. A method for preparing a high-temperature resistant, flame-retardant, and environmentally friendly putty, characterized in that the steps include... include: S1. By weight, mix 28.0-42.0 parts of hydroxyl-terminated polydimethylsiloxane, 8.0-18.0 parts of methylphenyl silicone resin, and 3.0-8.0 parts of dimethyl silicone oil to obtain a siloxane-based material; add 5.0-12.0 parts of fumed silica, 8.0-18.0 parts of mica powder, 6.0-14.0 parts of wollastonite powder, 3.0-8.0 parts of hollow glass microspheres, 5.0-12.0 parts of aluminum hydroxide, 4.0-10.0 parts of magnesium hydroxide, 5.0-12.0 parts of ammonium polyphosphate, 2.0-6.0 parts of zinc borate, 3.0-8.0 parts of borosilicate glass powder, and 1.0-4.0 parts of rutile titanium dioxide. Mixture A is prepared by vacuum kneading 2.0-6.0 parts of boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound, 1.0-5.0 parts of zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound, and 0.1-0.5 parts of polyether-modified siloxane defoamer at 35-45℃. Mixture B is prepared by mixing 4.0-10.0 parts of methyltrimethoxysilane, 3.0-8.0 parts of tetraethyl orthosilicate, 1.0-4.0 parts of vinyltrimethoxysilane, 0.5-2.0 parts of γ-aminopropyltriethoxysilane, 0.2-1.0 parts of diisopropoxydiacetylacetonate, 0.1-0.8 parts of bismuth isooctanoate, and 0-4.0 parts of anhydrous ethanol. S2. Store mixture A and mixture B separately; when using, mix mixture A and mixture B together and stir at 25-35℃.

2. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 1, characterized in that, In step S1, the vacuum kneading time is 60-120 min.

3. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 1, characterized in that, In step S2, the weight ratio of mixture A to mixture B is 100:(8-15).

4. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 1, characterized in that, The preparation method of the boron-nitrogen-phosphorus synergistic layered precursor-derived silicon-aluminum-magnesium ceramicized inorganic modified compound includes: A1. By weight, add 18.0-22.0 parts of magnesium nitrate hexahydrate and 8.0-12.0 parts of aluminum nitrate nonahydrate to 120.0-180.0 parts of deionized water, and stir at 25-35℃ to obtain a magnesium-aluminum mixed salt solution; add 1.5-3.5 parts of sodium metasilicate pentahydrate and 10.0-18.0 parts of sodium hydroxide to 60.0-100.0 parts of deionized water to obtain a silicon-containing alkaline precipitate; under a nitrogen atmosphere... Next, the silicon-containing alkaline precipitate is added to a magnesium-aluminum mixed salt solution, the pH is adjusted to 9.2-10.0, and the solution is aged at 55-70℃ to obtain a silicon-containing magnesium-aluminum layered hydroxide precursor slurry; 8.0-19.0 parts of disodium hydrogen phosphate dodecahydrate and 1.0-4.0 parts of boric acid are added to the silicon-containing magnesium-aluminum layered hydroxide precursor slurry, and the solution is reacted at 70-85℃. After filtration and washing, a boron-phosphorus modified magnesium-aluminum-silicon layered precursor is obtained. A2. Add boron-phosphorus modified magnesium-aluminum-silicon layered precursor to a mixture of 80.0-140.0 parts deionized water and 30.0-60.0 parts anhydrous ethanol, add 1.0-4.0 parts hexagonal boron nitride nanosheets, disperse ultrasonically, and then transfer to a hydrothermal reactor. React at 110-140℃ to obtain a boron-nitrogen-phosphorus synergistic layered precursor composite slurry. Filter, wash, dry, and grind the boron-nitrogen-phosphorus synergistic layered precursor composite slurry, calcine it at 420-520℃ under a nitrogen atmosphere, and then cool it.

5. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 4, characterized in that, In step A1, the stirring time is 30-60 min at 25-35℃; the aging time is 4-8 h at 55-70℃; and the reaction time is 3-6 h at 70-85℃.

6. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 4, characterized in that, In step A2, the ultrasonic dispersion time is 20-40 min; the reaction time at 110-140℃ is 6-10 h; and the calcination time at 420-520℃ is 1.5-3.0 h.

7. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 1, characterized in that, The preparation method of the zirconium-titanium-cerium modified aluminum phosphosilicate heat-resistant and flame-retardant inorganic modified compound includes: B1. By weight, mix 10.0-18.0 parts of tetraethyl orthosilicate, 40.0-70.0 parts of anhydrous ethanol, 10.0-18.0 parts of deionized water, and 0.2-0.6 parts of nitric acid, and stir at 25-35°C to obtain an acidic silica sol; add 0.8-2.0 parts of tetrabutyl titanate to the acidic silica sol and continue stirring to obtain a titanium-containing acidic silica sol; add 8.0-14.0 parts of aluminum isopropoxide and 40.0-80.0 parts of anhydrous... Ethanol is mixed and added to a titanium-containing acidic silica sol. The mixture is stirred at 50-65°C, and 3.0-6.0 parts of ammonium dihydrogen phosphate and 8.0-15.0 parts of deionized water are added to obtain a titanium-containing aluminum-phosphorus silica composite sol. 1.0-2.5 parts of zirconium oxynitrate hydrate and 0.3-1.2 parts of cerium nitrate hexahydrate are added to 30.0-60.0 parts of deionized water, and 0.5-1.5 parts of citric acid are added. The mixture is stirred at 45-60°C to obtain a zirconium-cerium composite metal salt solution. B2. Mix the titanium-containing phosphorus aluminum silicate composite sol and the zirconium-cerium composite metal salt solution, stir at 45-60℃, adjust the pH to 5.5-6.5 with ammonia water to obtain zirconium-titanium-cerium modified phosphorus aluminum silicate gel; dry and crush the zirconium-titanium-cerium modified phosphorus aluminum silicate gel, calcine it at 580-680℃ in air atmosphere, and then pulverize it.

8. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 7, characterized in that, In step B1, the stirring time is 40-80 minutes at 25-35℃ and 30-60 minutes at 45-60℃.

9. The method for preparing high-temperature resistant, flame-retardant, and environmentally friendly putty according to claim 7, characterized in that, In step B2, the calcination time at 580-680℃ is 2-4 hours.

10. A high-temperature resistant, flame-retardant, and environmentally friendly putty, characterized in that, The high-temperature resistant, flame-retardant, and environmentally friendly putty is prepared by the method described in any one of claims 1-9.