A composite fireproof and heat-insulating board and its preparation method

Abstract

The present invention provides a composite fireproof insulation board and a preparation method thereof. A composite fireproof insulation board comprises a modified straw aerogel layer, a modified ceramic fiber layer and a metal foil layer stacked in sequence; the modified straw aerogel layer is prepared by a sol-gel method from straw fiber, ultrafine inorganic powder and a composite crosslinking agent, wherein the mass percentage of straw fiber is 60-80%, the mass percentage of ultrafine inorganic powder is 15-30%, and the mass percentage of composite crosslinking agent is 5-15%; the modified ceramic fiber layer is composed of ceramic fiber, an inorganic binder and a functional filler; a first interface bonding layer is provided between the modified straw aerogel layer and the modified ceramic fiber layer, the first interface bonding layer being composed of an inorganic binder, ultrafine inorganic powder and an interface coupling agent; a second interface bonding layer is provided between the modified ceramic fiber layer and the metal foil layer, the second interface bonding layer being a nano-inorganic coating. The present invention has excellent interlayer bonding strength, stability, thermal insulation performance and fireproof performance.

Description

Technical Field

[0001] The invention relates to a composite fireproof and heat-insulating material, in particular to a composite fireproof and heat-insulating board and a preparation method thereof, and belongs to the technical field of building materials. Background Art

[0002] As a key material for building energy conservation, thermal insulation plays a vital role in reducing building energy consumption and improving living comfort. However, while traditional insulation materials such as polystyrene foam and polyurethane foam offer excellent thermal insulation properties, they often pose safety risks such as flammability and the release of toxic gases. On the other hand, inorganic insulation materials such as rock wool and glass wool, while offering good fire resistance, are relatively ineffective in insulation, and their production process is energy-intensive and polluting.

[0003] In recent years, biomass-based aerogel materials have attracted widespread attention due to their excellent thermal insulation properties, low density, and environmental friendliness. Straw aerogel, in particular, not only effectively utilizes agricultural waste but also offers excellent thermal insulation properties. However, single straw aerogel materials still face challenges in practical applications, such as insufficient strength and limited fire resistance.

[0004] Prior research has explored combining straw aerogel with other materials to improve their overall performance. However, these composite materials still lack interlayer bonding strength and stability, making them difficult to meet the requirements of long-term use and application in extreme environments. Summary of the Invention

[0005] Based on the above background, the purpose of the present invention is to provide a composite fireproof insulation board to solve the problems of insufficient interlayer bonding strength and poor stability of straw aerogel composite materials in the prior art, while having excellent thermal insulation and fireproof properties.

[0006] Another object of the present invention is to provide a method for preparing a composite fireproof thermal insulation board.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] A composite fireproof and heat-insulating board comprises a modified straw aerogel layer, a modified ceramic fiber layer and a metal foil layer stacked in sequence;

[0009] The modified straw aerogel layer is prepared from straw fibers, ultrafine inorganic powder and a composite crosslinking agent by a sol-gel method, wherein the mass percentage of the straw fibers is 60-80%, the mass percentage of the ultrafine inorganic powder is 15-30%, and the mass percentage of the composite crosslinking agent is 5-15%;

[0010] The modified ceramic fiber layer is composed of ceramic fibers, an inorganic binder, and a functional filler, wherein the mass percentage of the ceramic fibers is 60-75%, the mass percentage of the inorganic binder is 20-25%, and the mass percentage of the functional filler is 5-15%;

[0011] The metal foil layer is aluminum foil or stainless steel foil;

[0012] A first interface bonding layer is provided between the modified straw aerogel layer and the modified ceramic fiber layer, wherein the first interface bonding layer is composed of an inorganic binder, ultrafine inorganic powder and an interface coupling agent;

[0013] A second interface bonding layer is provided between the modified ceramic fiber layer and the metal foil layer, and the second interface bonding layer is a nano inorganic coating.

[0014] Preferably, the ultrafine inorganic powder is two or more of nano-silicon dioxide, nano-alumina, nano-titanium oxide, nano-zirconium oxide, and nano-calcium carbonate; the composite crosslinking agent is composed of an organic silicon crosslinker and an organic titanium crosslinker in a mass ratio of 2-8:1-5; the organic silicon crosslinker is one or more of methyltrimethoxysilane, ethyltriethoxysilane, and phenyltrimethoxysilane; and the organic titanium crosslinker is one or more of tetraisopropyl titanate and tetra-n-butyl titanate.

[0015] Preferably, the inorganic binder is water glass, potassium silicate or aluminum phosphate modified by a surfactant, the surfactant is one or more of sodium dodecylbenzene sulfonate, sodium lauryl sulfate, and polyethylene glycol, and the added amount of the surfactant is 0.5-2% of the mass of the inorganic binder, and the functional filler is one or more of expanded graphite, aluminum hydroxide, magnesium hydroxide, and montmorillonite.

[0016] Preferably, the nano-inorganic coating is one or more of a nano-silicon dioxide coating, a nano-aluminum oxide coating, and a nano-titanium oxide coating.

[0017] Preferably, the thickness of the modified straw aerogel layer is 15-35 mm, the thickness of the modified ceramic fiber layer is 8-18 mm, the thickness of the metal foil layer is 0.05-0.2 mm, the thickness of the first interface bonding layer is 0.5-2 mm, and the thickness of the second interface bonding layer is 0.1-0.5 mm.

[0018] Preferably, the density of the modified straw aerogel layer is 0.08-0.15 g / cm 3 , thermal conductivity is 0.015-0.025W / (m·K), compressive strength is 0.2-0.5MPa; the density of the modified ceramic fiber layer is 0.2-0.4g / cm 3, thermal conductivity is 0.03-0.05W / (m·K), and compressive strength is 0.5-1.0MPa.

[0019] A method for preparing a composite fireproof insulation board, the method comprising the following steps:

[0020] The straw fibers are immersed in a sodium hydroxide solution with a mass fraction of 2-5%, heated to 60-80° C. and immersed for 2-4 hours, ultrasonically treated for 30-60 minutes, filtered, placed in a cellulase solution with a mass fraction of 1-3%, enzymatically treated at 45-55° C. for 4-8 hours, filtered and washed until neutral, and then immersed in a silane coupling agent ethanol solution with a mass fraction of 1-3%, immersed at room temperature for 2-4 hours, washed, dried, and then crushed to 80-180 mesh;

[0021] The treated straw fibers are dispersed in an ethanol-water mixed solvent with a volume ratio of 7:3-9:1, a predetermined amount of ultrafine inorganic powder is added, and ultrasonic dispersion is performed for 30-60 minutes; a composite crosslinking agent is added, and the mixture is stirred at 20-30°C for 3-5 hours, and then aged at 55-75°C for 16-28 hours; the resulting sol is poured into a mold and placed in an environment of 40-60°C for gelation for 36-48 hours; the gel is immersed in ethanol for solvent exchange 2-3 times, and then heated to 60-80°C for drying for 24-48 hours, and finally heated to 120-150°C for heat treatment for 2-4 hours to obtain a modified straw aerogel layer;

[0022] The ceramic fibers are dispersed in water, an inorganic binder and a functional filler are added, and the mixture is dispersed by high-speed shearing for 15-30 minutes; the mixed slurry is formed into a sheet, heated to 80-100°C and dried for 4-6 hours, and then heated to 200-250°C and heat-treated for 1-2 hours to obtain a modified ceramic fiber layer;

[0023] The inorganic binder, ultrafine inorganic powder and interface coupling agent are mixed in a mass ratio of 5-8:1-3:0.1-0.5, and ultrasonically dispersed for 20-40 minutes to obtain a first interface bonding layer slurry; the nano inorganic coating component is dispersed in a solvent and ultrasonically treated for 30-60 minutes to obtain a second interface bonding layer slurry;

[0024] The first interface bonding layer slurry is evenly sprayed or scraped on the surface of the modified straw aerogel layer, and the modified ceramic fiber layer is covered on the modified straw aerogel layer; the second interface bonding layer slurry is evenly sprayed or scraped on the surface of the modified ceramic fiber layer, and the metal foil layer is covered on the modified ceramic fiber layer; the above multi-layer structure is placed in a hot press, hot-pressed at 120-150°C for 30-40 minutes at a pressure of 0.5-1.0 MPa, and then cooled to room temperature to obtain a composite fireproof insulation board.

[0025] Compared with the prior art, the present invention has the following advantages:

[0026] The composite fireproof and heat-insulating board of the present invention has excellent interlayer bonding strength, stability, thermal insulation performance and fireproof performance through the multi-layer composite structure and the interface bonding reinforcement effect of the interface bonding layer;

[0027] The preparation method of the composite fireproof and thermal insulation board of the present invention enables the modified straw aerogel layer to have an enhanced nanoporous structure and higher hydrophobicity and durability than ordinary straw aerogel, and is combined with a modified ceramic fiber layer with good stability and excellent thermal insulation performance, and improves the interlayer bonding strength of the entire board through two interface bonding layers, ultimately obtaining a composite fireproof and thermal insulation board with excellent interlayer bonding strength, stability, thermal insulation performance and fireproof performance. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described in detail below through specific examples. It should be understood that the implementation of the present invention is not limited to the following examples, and any form of modification and / or change made to the present invention will fall within the scope of protection of the present invention.

[0029] In the present invention, unless otherwise specified, all parts and percentages are by weight. The equipment and raw materials used are commercially available or commonly used in the art. The methods in the following embodiments, unless otherwise specified, are conventional methods in the art. The components or equipment in the following embodiments, unless otherwise specified, are all universal standard parts or components known to those skilled in the art. Their structures and principles are known to those skilled in the art through technical manuals or routine experimental methods.

[0030] The invention discloses a composite fireproof heat-insulating board, which comprises a modified straw aerogel layer, a modified ceramic fiber layer and a metal foil layer which are stacked in sequence.

[0031] The modified straw aerogel layer is prepared from straw fiber, ultrafine inorganic powder and composite crosslinking agent by sol-gel method, wherein the mass percentage of straw fiber is 60-80%, the mass percentage of ultrafine inorganic powder is 15-30% and the mass percentage of composite crosslinking agent is 5-15%.

[0032] The modified ceramic fiber layer consists of ceramic fiber, inorganic binder and functional filler, wherein the mass percentage of the ceramic fiber is 60-75%, the mass percentage of the inorganic binder is 20-25% and the mass percentage of the functional filler is 5-15%.

[0033] The metal foil layer is aluminum foil or stainless steel foil.

[0034] A first interface bonding layer is provided between the modified straw aerogel layer and the modified ceramic fiber layer. The first interface bonding layer consists of an inorganic binder, ultrafine inorganic powder and an interface coupling agent.

[0035] A second interface bonding layer is provided between the modified ceramic fiber layer and the metal foil layer, and the second interface bonding layer is a nano inorganic coating.

[0036] Specifically, the ultrafine inorganic powder is two or more of nano-silicon dioxide, nano-alumina, nano-titania, nano-zirconium oxide, and nano-calcium carbonate; the composite crosslinking agent is composed of an organic silicon crosslinker and an organic titanium crosslinker in a mass ratio of 2-8:1-5; the organic silicon crosslinker is one or more of methyltrimethoxysilane, ethyltriethoxysilane, and phenyltrimethoxysilane; and the organic titanium crosslinker is one or more of tetraisopropyl titanate and tetra-n-butyl titanate.

[0037] Specifically, the inorganic binder is water glass, potassium silicate or aluminum phosphate modified by a surfactant, the surfactant is one or more of sodium dodecylbenzene sulfonate, sodium lauryl sulfate, and polyethylene glycol, the added amount of the surfactant is 0.5-2% of the mass of the inorganic binder, and the functional filler is one or more of expanded graphite, aluminum hydroxide, magnesium hydroxide, and montmorillonite.

[0038] Specifically, the nano-inorganic coating is one or more of a nano-silicon dioxide coating, a nano-aluminum oxide coating, and a nano-titanium oxide coating.

[0039] Specifically, the thickness of the modified straw aerogel layer is 15-35 mm, the thickness of the modified ceramic fiber layer is 8-18 mm, the thickness of the metal foil layer is 0.05-0.2 mm, the thickness of the first interface bonding layer is 0.5-2 mm, and the thickness of the second interface bonding layer is 0.1-0.5 mm.

[0040] Specifically, the density of the modified straw aerogel layer is 0.08-0.15g / cm 3 , thermal conductivity is 0.015-0.025W / (m·K), compressive strength is 0.2-0.5MPa; density of modified ceramic fiber layer is 0.2-0.4g / cm 3 , thermal conductivity is 0.03-0.05W / (m·K), and compressive strength is 0.5-1.0MPa.

[0041] The present invention also discloses a method for preparing a composite fireproof insulation board, which comprises the following steps:

[0042] Preparation of modified straw aerogel layer:

[0043] The straw fibers are immersed in a sodium hydroxide solution with a mass fraction of 2-5%, heated to 60-80° C. and immersed for 2-4 hours, ultrasonically treated for 30-60 minutes, filtered, placed in a cellulase solution with a mass fraction of 1-3%, enzymatically treated at 45-55° C. for 4-8 hours, filtered and washed until neutral, and then immersed in a silane coupling agent ethanol solution with a mass fraction of 1-3%, immersed at room temperature for 2-4 hours, washed, dried, and then crushed to 80-180 mesh;

[0044] The treated straw fibers are dispersed in an ethanol-water mixed solvent with a volume ratio of 7:3-9:1, a predetermined amount of ultrafine inorganic powder is added, and ultrasonic dispersion is performed for 30-60 minutes; a composite cross-linking agent is added, and the mixture is stirred at 20-30°C for 3-5 hours, and then aged at 55-75°C for 16-28 hours; the obtained sol is poured into a mold and placed in an environment of 40-60°C for gelation for 36-48 hours; the gel is immersed in ethanol for solvent exchange 2-3 times, and then heated to 60-80°C for drying for 24-48 hours, and finally heated to 120-150°C for heat treatment for 2-4 hours to obtain a modified straw aerogel layer.

[0045] The modified straw aerogel layer obtained through the above steps has an enhanced nanoporous structure and higher hydrophobicity and durability than ordinary straw aerogels. First, soaking the straw fibers in sodium hydroxide solution dissolves some hemicellulose and lignin. Ultrasonic treatment further disperses the fibers and increases the specific surface area. Cellulase treatment selectively degrades some amorphous cellulose, creating more microporous structures. Subsequently, through the sol-gel process, a stable three-dimensional network structure is formed, maintaining nanoscale porous properties. Second, silane coupling agent treatment forms a hydrophobic layer on the fiber surface, improving the material's hydrophobicity. A predetermined amount of ultrafine inorganic powder is added during the sol-gel process to enhance the material's overall stability and durability.

[0046] Preparation of modified ceramic fiber layer:

[0047] The ceramic fibers are dispersed in water, and inorganic binders and functional fillers are added, and the mixture is dispersed by high-speed shearing for 15-30 minutes; the mixed slurry is formed into a sheet, heated to 80-100°C and dried for 4-6 hours, and then heated to 200-250°C and heat-treated for 1-2 hours to obtain a modified ceramic fiber layer.

[0048] The addition of an inorganic binder firmly connects the ceramic fibers, while the functional filler significantly enhances the material's thermal insulation properties. Heat treatment at 200-250°C not only promotes the curing of the inorganic binder but also triggers a phase transition in the functional filler, leading to the formation of a more stable high-temperature phase in the material, thereby improving its heat resistance.

[0049] Preparation of the first interface bonding layer slurry and the second interface bonding layer slurry:

[0050] The inorganic binder, ultrafine inorganic powder and interface coupling agent are mixed in a mass ratio of 5-8:1-3:0.1-0.5, and ultrasonically dispersed for 20-40 minutes to obtain a first interface bonding layer slurry; the nano-inorganic coating components are dispersed in a solvent and ultrasonically treated for 30-60 minutes to obtain a second interface bonding layer slurry.

[0051] Preparation of composite fireproof insulation board:

[0052] The first interface bonding layer slurry is evenly sprayed or scraped on the surface of the modified straw aerogel layer, and the modified ceramic fiber layer is covered on the modified straw aerogel layer; the second interface bonding layer slurry is evenly sprayed or scraped on the surface of the modified ceramic fiber layer, and the metal foil layer is covered on the modified ceramic fiber layer; the above multi-layer structure is placed in a hot press, hot-pressed at 120-150°C for 30-40 minutes at a pressure of 0.5-1.0 MPa, and then cooled to room temperature to obtain a composite fireproof insulation board.

[0053] The following is a plurality of embodiments combined with comparative examples to further illustrate a composite fireproof insulation board and a preparation method thereof disclosed in the present invention.

[0054] Example 1

[0055] Preparation of modified straw aerogel layer:

[0056] The straw fiber was soaked in a 3% by mass sodium hydroxide solution, heated to 70°C and soaked for 3 hours, ultrasonically treated for 45 minutes, filtered, placed in a 2% by mass cellulase solution, enzymatically treated at 50°C for 6 hours, filtered and washed until neutral, and then immersed in a 2% by mass γ-aminopropyltriethoxysilane ethanol solution, immersed at room temperature for 3 hours, washed and dried, and then crushed to 100 mesh.

[0057] The treated straw fibers were dispersed in an ethanol-water mixed solvent with a volume ratio of 8:2, and nano-silica and nano-alumina (mass ratio of 3:1) were added, and ultrasonic dispersion was performed for 45 minutes. A composite crosslinker (methyltrimethoxysilane and tetraisopropyl titanate, mass ratio of 5:2) was added, and the mixture was stirred at 25°C for 4 hours, and then aged at 65°C for 24 hours. The obtained sol was poured into a mold and placed in a 50°C environment for gelation for 42 hours. The gel was immersed in ethanol for solvent exchange three times, then heated to 70°C for drying for 36 hours, and finally heated to 135°C for heat treatment for 3 hours to obtain a modified straw aerogel layer.

[0058] The mass percentage of the straw fiber is 70%, the mass percentage of the ultrafine inorganic powder is 22%, and the mass percentage of the composite cross-linking agent is 8%.

[0059] Preparation of modified ceramic fiber layer:

[0060] Ceramic fibers were dispersed in water, and an inorganic binder (water glass modified with 1% sodium dodecylbenzene sulfonate) and functional fillers (expanded graphite and aluminum hydroxide, in a 1:1 mass ratio) were added. The mixture was dispersed under high-speed shear for 20 minutes. The mixed slurry was then sheet-formed, heated to 90°C for drying for 5 hours, and then heat-treated at 225°C for 1.5 hours to obtain a modified ceramic fiber layer.

[0061] The mass percentage of the ceramic fiber is 68%, the mass percentage of the inorganic binder is 22%, and the mass percentage of the functional filler is 10%.

[0062] Preparation of interfacial bonding layer:

[0063] First interface bonding layer: water glass, nano-silica and γ-aminopropyltriethoxysilane were mixed in a mass ratio of 6.5:2:0.3, and ultrasonically dispersed for 30 minutes to obtain a first interface bonding layer slurry.

[0064] Second interface bonding layer: Nano-silica was dispersed in ethanol solvent and ultrasonically treated for 45 minutes to obtain a second interface bonding layer slurry.

[0065] Preparation of composite fireproof insulation board:

[0066] The first interface bonding layer slurry was evenly sprayed on the surface of the modified straw aerogel layer, and the modified ceramic fiber layer was covered on the modified straw aerogel layer; the second interface bonding layer slurry was evenly sprayed on the surface of the modified ceramic fiber layer, and aluminum foil was covered on the modified ceramic fiber layer; the above multilayer structure was placed in a hot press, hot-pressed at 135°C for 35 minutes at a pressure of 0.75 MPa, and then cooled to room temperature to obtain a composite fireproof insulation board.

[0067] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 25 mm, the thickness of the modified ceramic fiber layer is 13 mm, the thickness of the aluminum foil layer is 0.1 mm, the thickness of the first interface bonding layer is 1 mm, and the thickness of the second interface bonding layer is 0.3 mm.

[0068] Example 2

[0069] The preparation method is the same as that of Example 1, except that:

[0070] To prepare the modified straw aerogel layer, straw fibers were immersed in a 4% sodium hydroxide solution. The ultrafine inorganic powders consisted of nano-silica and nano-titanium oxide (in a 2:1 mass ratio), and the composite crosslinker consisted of ethyltriethoxysilane and tetra-n-butyl titanate (in a 4:1 mass ratio). The weight percentage of the straw fibers was 75%, the weight percentage of the ultrafine inorganic powder was 18%, and the weight percentage of the composite crosslinker was 7%.

[0071] When preparing the ceramic fiber layer, the inorganic binder is potassium silicate modified with 1.5% sodium lauryl sulfate, and the functional fillers are magnesium hydroxide and montmorillonite (mass ratio of 2:1). The mass percentage of ceramic fiber is 65%, the mass percentage of inorganic binder is 24%, and the mass percentage of functional filler is 11%.

[0072] When preparing the first interface bonding layer, potassium silicate, nano-alumina and γ-aminopropyltriethoxysilane are mixed in a mass ratio of 7:1.5:0.2.

[0073] When preparing the second interface bonding layer, nano-aluminum oxide is dispersed in isopropyl alcohol.

[0074] Stainless steel foil was used as the metal foil layer, and the hot pressing temperature was 140°C and the pressure was 0.8 MPa.

[0075] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 30 mm, the thickness of the modified ceramic fiber layer is 15 mm, the thickness of the stainless steel foil layer is 0.15 mm, the thickness of the first interface bonding layer is 1.5 mm, and the thickness of the second interface bonding layer is 0.4 mm.

[0076] Example 3

[0077] The preparation method is the same as that of Example 1, except that:

[0078] To prepare the modified straw aerogel layer, straw fibers were immersed in a 2.5% sodium hydroxide solution. The ultrafine inorganic powders consisted of nano-silica, nano-alumina, and nano-zirconium oxide (in a 2:1:1 mass ratio), and the composite crosslinker consisted of phenyltrimethoxysilane and tetraisopropyl titanate (in a 3:1 mass ratio). The weight percentage of the straw fibers was 65%, the weight percentage of the ultrafine inorganic powder was 25%, and the weight percentage of the composite crosslinker was 10%.

[0079] When preparing the ceramic fiber layer, the inorganic binder is aluminum phosphate modified with 0.8% polyethylene glycol, and the functional fillers are expanded graphite and aluminum hydroxide (mass ratio of 1:2). The mass percentage of ceramic fiber is 70%, the mass percentage of inorganic binder is 21%, and the mass percentage of functional filler is 9%.

[0080] When preparing the first interface bonding layer, aluminum phosphate, nano-titanium oxide and silane coupling agent KH570 are mixed in a mass ratio of 5.5:2.5:0.4.

[0081] When preparing the second interface bonding layer, nano-titanium oxide is dispersed in n-butanol.

[0082] The hot pressing temperature was 130°C and the pressure was 0.7 MPa.

[0083] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 20 mm, the thickness of the modified ceramic fiber layer is 10 mm, the thickness of the aluminum foil layer is 0.08 mm, the thickness of the first interface bonding layer is 0.8 mm, and the thickness of the second interface bonding layer is 0.2 mm.

[0084] Example 4

[0085] The preparation method is the same as that of Example 1, except that:

[0086] To prepare the modified straw aerogel layer, straw fibers were immersed in a 3.5% sodium hydroxide solution. The ultrafine inorganic powders consisted of nano-silica and nano-calcium carbonate (in a 1:1 mass ratio), and the composite crosslinker consisted of methyltrimethoxysilane and tetra-n-butyl titanate (in a 6:1 mass ratio). The mass percentage of straw fibers was 72%, the mass percentage of ultrafine inorganic powder was 20%, and the mass percentage of the composite crosslinker was 8%.

[0087] When preparing the ceramic fiber layer, the inorganic binder is water glass modified with 1.2% sodium dodecylbenzenesulfonate, and the functional fillers are magnesium hydroxide and montmorillonite (mass ratio of 3:1). The mass percentage of ceramic fiber is 67%, the mass percentage of inorganic binder is 23%, and the mass percentage of functional filler is 10%.

[0088] When preparing the first interface bonding layer, water glass, nano calcium carbonate and silane coupling agent KH560 are mixed according to a mass ratio of 6:2.5:0.25.

[0089] When preparing the second interface bonding layer, nano-silicon dioxide and nano-aluminum oxide (mass ratio of 1:1) are dispersed in ethanol.

[0090] Stainless steel foil was used as the metal foil layer, and the hot pressing temperature was 145° C. and the pressure was 0.85 MPa.

[0091] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 28 mm, the thickness of the modified ceramic fiber layer is 12 mm, the thickness of the stainless steel foil layer is 0.12 mm, the thickness of the first interface bonding layer is 1.2 mm, and the thickness of the second interface bonding layer is 0.35 mm.

[0092] Example 5

[0093] The preparation method is the same as that of Example 1, except that:

[0094] To prepare the modified straw aerogel layer, straw fibers were immersed in a 4.5% sodium hydroxide solution. The ultrafine inorganic powders consisted of nano-silica, nano-alumina, and nano-titanium oxide (in a 2:1:1 mass ratio), and the composite crosslinker consisted of ethyltriethoxysilane and tetraisopropyl titanate (in a 7:2 mass ratio). The mass percentage of straw fibers was 68%, the mass percentage of ultrafine inorganic powder was 23%, and the mass percentage of the composite crosslinker was 9%.

[0095] When preparing the ceramic fiber layer, the inorganic binder is potassium silicate modified with 1.8% sodium lauryl sulfate, and the functional fillers are expanded graphite, aluminum hydroxide, and magnesium hydroxide (in a 1:1:1 weight ratio). The weight percentage of the ceramic fiber is 69%, the weight percentage of the inorganic binder is 20%, and the weight percentage of the functional filler is 11%.

[0096] When preparing the first interface bonding layer, potassium silicate, nano-alumina and silane coupling agent KH792 are mixed in a mass ratio of 7.5:1.8:0.35.

[0097] When preparing the second interface bonding layer, nano-aluminum oxide and nano-titanium oxide (mass ratio of 1:1) are dispersed in an ethanol-water mixed solvent (volume ratio of 4:1).

[0098] The hot pressing temperature is 138°C and the pressure is 0.78 MPa.

[0099] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 32 mm, the thickness of the modified ceramic fiber layer is 16 mm, the thickness of the aluminum foil layer is 0.18 mm, the thickness of the first interface bonding layer is 1.8 mm, and the thickness of the second interface bonding layer is 0.45 mm.

[0100] Example 6

[0101] The preparation method is the same as that of Example 1, except that:

[0102] To prepare the modified straw aerogel layer, straw fibers were immersed in a 3.8% sodium hydroxide solution. The ultrafine inorganic powders consisted of nano-silica and nano-zirconium oxide (in a 4:1 mass ratio), and the composite crosslinker consisted of phenyltrimethoxysilane and tetra-n-butyl titanate (in a 5:1 mass ratio). The mass percentage of straw fibers was 73%, the mass percentage of ultrafine inorganic powder was 19%, and the mass percentage of the composite crosslinker was 8%.

[0103] When preparing the ceramic fiber layer, the inorganic binder is aluminum phosphate modified with 1% polyethylene glycol, and the functional fillers are aluminum hydroxide and montmorillonite (mass ratio of 3:2). The mass percentage of ceramic fiber is 71%, the mass percentage of inorganic binder is 21%, and the mass percentage of functional filler is 8%.

[0104] When preparing the first interface bonding layer, aluminum phosphate, nano zirconium oxide and silane coupling agent KH550 were mixed in a mass ratio of 6.8:2.2:0.28.

[0105] When preparing the second interface bonding layer, nano-silicon dioxide and nano-titanium oxide (mass ratio of 2:1) are dispersed in isopropyl alcohol.

[0106] Stainless steel foil was used as the metal foil layer, and the hot pressing temperature was 142°C and the pressure was 0.82 MPa.

[0107] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 22 mm, the thickness of the modified ceramic fiber layer is 11 mm, the thickness of the stainless steel foil layer is 0.14 mm, the thickness of the first interface bonding layer is 1.3 mm, and the thickness of the second interface bonding layer is 0.38 mm.

[0108] Example 7

[0109] The preparation method is the same as that of Example 1, except that:

[0110] To prepare the modified straw aerogel layer, straw fibers were immersed in a 3.2% sodium hydroxide solution. The ultrafine inorganic powders consisted of nano-silica, nano-alumina, and nano-calcium carbonate (in a 3:1:1 mass ratio), and the composite crosslinker consisted of methyltrimethoxysilane and tetraisopropyl titanate (in a 4:1 mass ratio). The mass percentage of straw fibers was 71%, the mass percentage of ultrafine inorganic powder was 21%, and the mass percentage of the composite crosslinker was 8%.

[0111] When preparing the ceramic fiber layer, the inorganic binder is water glass modified with 1.5% sodium dodecylbenzene sulfonate, and the functional fillers are expanded graphite, magnesium hydroxide, and montmorillonite (in a mass ratio of 2:2:1). The mass percentage of ceramic fiber is 66%, the mass percentage of inorganic binder is 22%, and the mass percentage of functional filler is 12%.

[0112] When preparing the first interface bonding layer, water glass, nano-alumina and silane coupling agent KH570 are mixed according to a mass ratio of 6.2:2.3:0.32.

[0113] When preparing the second interface bonding layer, nano-silicon dioxide, nano-aluminum oxide and nano-titanium oxide (mass ratio of 2:1:1) are dispersed in an ethanol-water mixed solvent (volume ratio of 3:1).

[0114] The hot pressing temperature was 137°C and the pressure was 0.76 MPa.

[0115] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 27 mm, the thickness of the modified ceramic fiber layer is 14 mm, the thickness of the aluminum foil layer is 0.16 mm, the thickness of the first interface bonding layer is 1.6 mm, and the thickness of the second interface bonding layer is 0.42 mm.

[0116] Example 8

[0117] The preparation method is the same as that of Example 1, except that:

[0118] To prepare the modified straw aerogel layer, straw fibers were immersed in a 3.6% sodium hydroxide solution. The ultrafine inorganic powders consisted of nano-silica and nano-titanium oxide (in a 5:2 mass ratio), and the composite crosslinker consisted of ethyltriethoxysilane and tetra-n-butyl titanate (in a 6:1 mass ratio). The mass percentage of straw fibers was 74%, the mass percentage of ultrafine inorganic powder was 18%, and the mass percentage of the composite crosslinker was 8%.

[0119] When preparing the ceramic fiber layer, the inorganic binder is potassium silicate modified with 0.9% polyethylene glycol, and the functional fillers are aluminum hydroxide and magnesium hydroxide (mass ratio of 1:1). The mass percentage of ceramic fiber is 72%, the mass percentage of inorganic binder is 19%, and the mass percentage of functional filler is 9%.

[0120] When preparing the first interface bonding layer, potassium silicate, nano-titanium oxide and KH560 are mixed in a mass ratio of 7.2:1.6:0.26.

[0121] When preparing the second interface bonding layer, nano-silicon dioxide and nano-zirconium oxide (mass ratio of 3:1) are dispersed in n-butanol.

[0122] Stainless steel foil was used as the metal foil layer, and the hot pressing temperature was 133°C and the pressure was 0.72 MPa.

[0123] In the final composite fireproof insulation board, the thickness of the modified straw aerogel layer is 24 mm, the thickness of the modified ceramic fiber layer is 12 mm, the thickness of the stainless steel foil layer is 0.13 mm, the thickness of the first interface bonding layer is 1.1 mm, and the thickness of the second interface bonding layer is 0.32 mm.

[0124] Comparative Example 1

[0125] The preparation method is the same as that of Example 1, except that no ultrafine inorganic powder is added.

[0126] Comparative Example 2

[0127] The preparation method is the same as that of Example 1, except that no composite cross-linking agent is added.

[0128] Comparative Example 3

[0129] The preparation method is the same as that of Example 1, except that no functional filler is added.

[0130] Comparative Example 4

[0131] The preparation method is the same as that of Example 1, except that the first interface bonding layer is not provided.

[0132] Comparative Example 5

[0133] The preparation method is the same as that of Example 1, except that the second interface bonding layer is not provided.

[0134] Comparative Example 6

[0135] The preparation method is the same as that of Example 1, except that no metal foil layer is provided.

[0136] Comparative Example 7

[0137] Commercially available polystyrene foam board.

[0138] Comparative Example 8

[0139] Commercially available rock wool board.

[0140] Comparative Example 9

[0141] Commercially available mineral wool and cement-based refractory layer composite board.

[0142] Performance Testing

[0143] The composite fireproof insulation boards prepared in Examples 1-8 and Comparative Examples 1-6 were subjected to performance tests, and the test results are shown in the following table:

[0144]

[0145]

[0146] As can be seen from the above table, the composite fireproof insulation boards prepared in Examples 1-8 of the present invention have excellent comprehensive properties, low thermal conductivity, high compressive strength, and good fire resistance. In contrast, the performance of Comparative Examples 1-6 is significantly reduced in the absence of any single key component or single key structure. Specifically, Comparative Example 1 lacks ultrafine inorganic powder, resulting in a loose material structure, increased thermal bridges, decreased mechanical strength, and reduced fire resistance. The presence of ultrafine inorganic powder fills the microscopic pores of the material, reduces thermal conductivity, and contributes to the improvement of compressive strength and interlayer bonding strength. Comparative Example 2 lacks a composite crosslinking agent, which also leads to a loose structure and increased thermal conductivity within the material. Comparative Example 3 lacks a functional filler, resulting in a decrease in the material's performance in terms of fire resistance and mechanical strength. The lack of an interface bonding layer in Comparative Examples 4 and 5 mainly leads to a decrease in the material's mechanical properties, especially the interlayer bonding strength. Comparative Example 6 lacks a metal foil layer. Although it has little effect on the material's thermal conductivity, it significantly reduces the fire resistance limit. This shows that there is a synergistic effect between the components and structures of the composite fireproof insulation board of the present invention.

[0147] The thermal conductivity coefficients of Examples 1-8 are all between 0.017-0.020 W / (m·K), which are significantly better than all comparative examples, especially 40-60% lower than the polystyrene foam board (Comparative Example 7), rock wool board (Comparative Example 8) and mineral wool and cement-based fire-resistant layer composite board (Comparative Example 9). This shows that the composite fireproof insulation board of the present invention has excellent thermal insulation performance. The compressive strength of Examples 1-8 is between 0.40-0.45 MPa, which is significantly higher than all comparative examples. In particular, it is about 3 times higher than the polystyrene foam board (Comparative Example 7), about 7 times higher than the rock wool board (Comparative Example 8), and about 1 times higher than the mineral wool and cement-based fire-resistant layer composite board (Comparative Example 9). This shows that the composite fireproof insulation board of the present invention has excellent mechanical properties. The fire resistance limits of Examples 1-8 are all between 4.1-4.4 hours, which is better than or equivalent to most comparative examples. In particular, it is about 8 times higher than the polystyrene foam board (Comparative Example 7), equivalent to the rock wool board (Comparative Example 8), and about 15% higher than the composite board of mineral wool and cement-based fire-resistant layer (Comparative Example 9). This fully demonstrates that the composite fireproof insulation board of the present invention has excellent fireproof performance. The interlayer bonding strength of Examples 1-8 is between 0.14-0.16MPa, which is significantly higher than all comparative examples. In particular, it is about 3 times higher than the polystyrene foam board (Comparative Example 7), about 50 times higher than the rock wool board (Comparative Example 8), and about 2 times higher than the composite board of mineral wool and cement-based fire-resistant layer (Comparative Example 9). This shows that the composite fireproof insulation board of the present invention has better integrity and durability. The dimensional change rates of Examples 1-8 are all between 0.2-0.3%, which are better than or equivalent to most comparative examples, and in particular are significantly better than the polystyrene foam board (Comparative Example 7). This shows that the composite fireproof insulation board of the present invention is not easy to deform during use and has good dimensional stability.

[0148] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A composite fireproof insulation board, characterized by: The composite fireproof and heat-insulating board comprises a modified straw aerogel layer, a modified ceramic fiber layer and a metal foil layer stacked in sequence; The modified straw aerogel layer is prepared from straw fibers, ultrafine inorganic powder and a composite crosslinking agent by a sol-gel method, wherein the mass percentage of the straw fibers is 60-80%, the mass percentage of the ultrafine inorganic powder is 15-30%, and the mass percentage of the composite crosslinking agent is 5-15%; The modified ceramic fiber layer is composed of ceramic fibers, an inorganic binder, and a functional filler, wherein the mass percentage of the ceramic fibers is 60-75%, the mass percentage of the inorganic binder is 20-25%, and the mass percentage of the functional filler is 5-15%; The metal foil layer is aluminum foil or stainless steel foil; A first interface bonding layer is provided between the modified straw aerogel layer and the modified ceramic fiber layer, wherein the first interface bonding layer is composed of an inorganic binder, ultrafine inorganic powder and an interface coupling agent; A second interface bonding layer is provided between the modified ceramic fiber layer and the metal foil layer, and the second interface bonding layer is a nano inorganic coating; The ultrafine inorganic powder is two or more of nano-silicon dioxide, nano-aluminum oxide, nano-titanium oxide, nano-zirconium oxide, and nano-calcium carbonate; the composite cross-linking agent is composed of an organic silicon cross-linking agent and an organic titanium cross-linking agent in a mass ratio of 2-8:1-5; the organic silicon cross-linking agent is one or more of methyltrimethoxysilane, ethyltriethoxysilane, and phenyltrimethoxysilane; and the organic titanium cross-linking agent is one or more of tetraisopropyl titanate and tetra-n-butyl titanate; The inorganic binder is water glass, potassium silicate or aluminum phosphate modified by a surfactant, the surfactant is one or more of sodium dodecylbenzene sulfonate, sodium lauryl sulfate, and polyethylene glycol, and the amount of the surfactant added is 0.5-2% of the mass of the inorganic binder, and the functional filler is one or more of expanded graphite, aluminum hydroxide, magnesium hydroxide, and montmorillonite; The nano inorganic coating is one or more of a nano silicon dioxide coating, a nano aluminum oxide coating, and a nano titanium oxide coating.

2. The composite fireproof insulation board according to claim 1, characterized in that: The thickness of the modified straw aerogel layer is 15-35 mm, the thickness of the modified ceramic fiber layer is 8-18 mm, the thickness of the metal foil layer is 0.05-0.2 mm, the thickness of the first interface bonding layer is 0.5-2 mm, and the thickness of the second interface bonding layer is 0.1-0.5 mm.

3. The composite fireproof insulation board according to claim 1, characterized in that: The density of the modified straw aerogel layer is 0.08-0.15 g / cm³, the thermal conductivity is 0.015-0.025 W / (m·K), and the compressive strength is 0.2-0.5 MPa; the density of the modified ceramic fiber layer is 0.2-0.4 g / cm³, the thermal conductivity is 0.03-0.05 W / (m·K), and the compressive strength is 0.5-1.0 MPa.

4. A method for preparing the composite fireproof insulation board according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: The straw fibers are immersed in a sodium hydroxide solution with a mass fraction of 2-5%, heated to 60-80°C and immersed for 2-4 hours, ultrasonically treated for 30-60 minutes, filtered, placed in a cellulase solution with a mass fraction of 1-3%, enzymatically treated at 45-55°C for 4-8 hours, filtered and washed until neutral, and then immersed in a silane coupling agent ethanol solution with a mass fraction of 1-3%, immersed at room temperature for 2-4 hours, washed and dried, and then crushed to 80-180 mesh; The treated straw fibers are dispersed in an ethanol-water mixed solvent with a volume ratio of 7:3-9:1, a predetermined amount of ultrafine inorganic powder is added, and ultrasonic dispersion is performed for 30-60 minutes; a composite crosslinking agent is added, and the mixture is stirred at 20-30°C for 3-5 hours, and then aged at 55-75°C for 16-28 hours; the resulting sol is poured into a mold and placed in an environment of 40-60°C for gelation for 36-48 hours; the gel is immersed in ethanol for solvent exchange 2-3 times, and then heated to 60-80°C for drying for 24-48 hours, and finally heated to 120-150°C for heat treatment for 2-4 hours to obtain a modified straw aerogel layer; The ceramic fibers are dispersed in water, an inorganic binder and a functional filler are added, and the mixture is dispersed by high-speed shearing for 15-30 minutes; the mixed slurry is formed into a sheet, heated to 80-100°C and dried for 4-6 hours, and then heated to 200-250°C and heat-treated for 1-2 hours to obtain a modified ceramic fiber layer; The inorganic binder, ultrafine inorganic powder and interface coupling agent are mixed in a mass ratio of 5-8:1-3:0.1-0.5, and ultrasonically dispersed for 20-40 minutes to obtain a first interface bonding layer slurry; the nano inorganic coating component is dispersed in a solvent and ultrasonically treated for 30-60 minutes to obtain a second interface bonding layer slurry; The first interface bonding layer slurry is evenly sprayed or scraped on the surface of the modified straw aerogel layer, and the modified ceramic fiber layer is covered on the modified straw aerogel layer; the second interface bonding layer slurry is evenly sprayed or scraped on the surface of the modified ceramic fiber layer, and the metal foil layer is covered on the modified ceramic fiber layer to obtain a multilayer structure; the above multilayer structure is placed in a hot press, hot pressed at 120-150°C for 30-40 minutes at a pressure of 0.5-1.0 MPa, and then cooled to room temperature to obtain a composite fireproof insulation board.

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