A building external wall insulation board based on pearl wool and a preparation method thereof

Abstract

The application relates to the technical field of building external wall thermal insulation material preparation, in particular to a building external wall thermal insulation board based on pearl wool and a preparation method thereof, which comprises a core layer and a composite surface layer, the core layer and the composite surface layers on both sides of the core layer form a sandwich structure, and the core layer raw materials are as follows in parts by weight: pearl wool particles 40-60 parts, graphene loaded expanded graphite 5-15 parts, nano silicon dioxide aerogel 3-10 parts, ammonium polyphosphate 10-20 parts, pentaerythritol 5-12 parts, melamine 3-8 parts, ethylene-vinyl acetate copolymer 15-25 parts, maleic anhydride grafted polyethylene 5-10 parts, nano montmorillonite 2-6 parts, silicon carbide whisker 1-5 parts, silane coupling agent KH560 0.5-2 parts, antioxidant 1010 0.2-0.8 parts, amino-terminated polyether 3-8 parts and hindered amine light stabilizer 770 0.3-1 part. The thermal insulation board has excellent thermal insulation, mechanical and flame-retardant properties, good weather resistance, stable size, strong construction adaptability, can recycle pearl wool, and has practical and environmental protection values.

Description

Technical Field

[0001] This invention relates to the field of building exterior wall insulation material preparation technology, specifically to a building exterior wall insulation board based on pearl cotton and its preparation method. Background Technology

[0002] Building exterior wall insulation materials are core materials for achieving building energy conservation. Their insulation performance, mechanical strength, and safety performance are directly related to building energy consumption and resident safety. Currently, the mainstream exterior wall insulation materials on the market mainly include polystyrene boards, extruded polystyrene boards, rock wool boards, and pearl cotton-based insulation boards, but all of them have obvious technical shortcomings.

[0003] Polystyrene boards and extruded polystyrene boards have excellent thermal insulation properties, but poor flame retardancy. They are prone to melting and dripping when exposed to fire, posing a serious fire hazard. Furthermore, they are susceptible to aging and shrinkage with prolonged use, leading to cracking and detachment of the insulation layer. Rock wool boards have outstanding flame retardancy, but their high thermal conductivity limits their insulation effect. They are also highly hygroscopic, with their insulation performance decreasing sharply after absorbing water. Additionally, their fibers are prone to shedding, impacting the health of construction workers and the environment.

[0004] EPE foam-based insulation boards have gained increasing attention due to their lightweight and good insulation properties, but existing products have several drawbacks. Traditional EPE foam insulation boards are mostly made of single-layer EPE foam or simple composite structures. The core layer is only made by physically mixing flame retardants and insulation fillers, without a chemical cross-linking network, resulting in poor structural stability, insufficient compression and impact resistance, and susceptibility to damage from external forces. The surface layer is mostly a single cement-based material, which has poor compatibility with the core layer, easily leading to delamination. Furthermore, its weather resistance and crack resistance are poor, and long-term outdoor exposure can cause aging, yellowing, cracking, and water seepage.

[0005] Furthermore, in the existing manufacturing process of pearl cotton insulation boards, the filler and matrix have poor compatibility, leading to easy agglomeration and uneven thermal insulation and flame retardant performance. The curing process is simple and not optimized for composite structures, resulting in high product moisture content and poor dimensional stability, affecting construction quality and service life. With the continuous improvement of building energy efficiency standards and safety requirements, the shortcomings of traditional pearl cotton-based insulation boards in terms of structural stability, mechanical properties, weather resistance, and manufacturing process adaptability are becoming increasingly prominent. Developing a pearl cotton-based exterior wall insulation board with excellent thermal insulation, mechanical strength, flame retardancy, and durability, along with an efficient manufacturing method, has become a key issue urgently needing to be addressed in this field. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] To address the shortcomings of existing technologies, this invention provides a building exterior wall insulation board based on pearl cotton and its preparation method.

[0008] (II) Technical Solution

[0009] A building exterior wall insulation board based on pearl cotton includes a core layer and a composite surface layer. The core layer is laminated with a composite surface layer on both sides, forming a "surface layer-core layer-surface layer" sandwich structure.

[0010] The core layer raw materials, by weight, are: 40-60 parts pearl cotton particles, 5-15 parts graphene-supported expanded graphite, 3-10 parts nano-silica aerogel, 10-20 parts ammonium polyphosphate, 5-12 parts pentaerythritol, 3-8 parts melamine, 15-25 parts ethylene-vinyl acetate copolymer, 5-10 parts maleic anhydride-grafted polyethylene, 2-6 parts nano-montmorillonite, 1-5 parts silicon carbide whiskers, 0.5-2 parts silane coupling agent KH560, 0.2-0.8 parts antioxidant 1010, 3-8 parts amino-terminated polyether, and 0.3-1 parts hindered amine light stabilizer 770.

[0011] The composite surface layer raw materials, by weight, are: 30-50 parts cement-based cementitious materials, 8-15 parts pearl cotton short fibers, 10-20 parts fly ash, 2-5 parts hydroxypropyl methylcellulose ether, 1-4 parts polyacrylonitrile fibers, 2-6 parts titanium dioxide, 5-12 parts waterborne epoxy resin emulsion, 3-8 parts silane-modified polyurethane emulsion, 0.1-0.5 parts defoamer, and 15-25 parts deionized water.

[0012] During the core layer preparation process, amino-terminated polyether and maleic anhydride-grafted polyethylene undergo an esterification reaction. The reaction formula is maleic anhydride-grafted polyethylene-COOH + amino-terminated polyether-NH2 → maleic anhydride-grafted polyethylene-CO-NH-polyether + H2O. This reaction constructs a three-dimensional cross-linked network, improving the structural stability of the core layer. In the composite surface layer, waterborne epoxy resin emulsion and silane-modified polyurethane emulsion undergo a cross-linking reaction to form a dense structure, enhancing the protective performance of the surface layer.

[0013] This invention also includes the requirement that the graphene-supported expanded graphite in the core layer be pretreated and modified with the silane coupling agent KH560. During the modification process, an interfacial coupling reaction occurs, with the reaction formula being KH560-Si(OCH3)3 + graphene-supported expanded graphite-OH → KH560-Si(OCH3)2-O-graphite + CH3OH. After modification, the hydroxyl content on the surface of the graphene-supported expanded graphite is reduced to 0.3-0.6 mmol / g, the compatibility with organic components such as ethylene-vinyl acetate copolymer is improved by more than 40%, the dispersion uniformity is significantly improved, and the fluctuation of thermal conductivity caused by agglomeration is avoided.

[0014] This invention also includes ensuring that the crosslinking reaction between the waterborne epoxy resin emulsion and the silane-modified polyurethane emulsion in the composite surface layer is fully carried out during shearing and stirring, achieving a crosslinking degree of 60-80%. The titanium dioxide is treated with an aluminum coating process, with a coating thickness of 5-15 nm. After coating treatment, the weather resistance of the titanium dioxide is improved by more than 30%, effectively resisting surface aging and yellowing caused by ultraviolet radiation. The polyacrylonitrile fiber is modified, with a surface hydroxylation treatment and a hydroxyl content of 1.0-1.5 mmol / g, increasing the bonding strength with cement-based cementitious materials by 60% and enhancing the crack resistance of the surface layer.

[0015] The nano-silica aerogel of this invention is modified with methyltriethoxysilane, with a particle size of 20-50 nm, a specific surface area of ​​600-800 m² / g, a porosity of 85-95%, and a thermal conductivity ≤0.025 W / (m·K). After modification with methyltriethoxysilane, the hydrophobic contact angle of the aerogel surface is ≥120°, and the hygroscopicity is reduced to below 5%, effectively avoiding the problem of decreased thermal insulation performance after moisture absorption in traditional aerogels, and making it suitable for high-humidity building environments.

[0016] The silicon carbide whiskers of this invention have an aspect ratio of 15-30:1, a diameter of 50-200 nm, a length of 1-5 μm, a purity of ≥98%, a tensile strength of ≥3 GPa, and an elastic modulus of ≥400 GPa. The silicon carbide whiskers require pretreatment with γ-aminopropyltriethoxysilane. After pretreatment, the surface amino content is 1.2-1.8 mmol / g, increasing the bonding strength with the ethylene-vinyl acetate copolymer matrix by more than 50%, forming a "fiber-reinforced" structure in the core layer, and significantly improving the core layer's compressive strength and impact resistance.

[0017] In this invention, the cement-based cementitious material is a mixture of ordinary Portland cement and sulfoaluminate cement in a mass ratio of 3:1-2:1, with both cement grades ≥42.5R. The sulfoaluminate cement has an initial setting time of 15-30 min and a final setting time of 60-90 min, with a hydration heat peak reduced to below 200 J / g, effectively reducing temperature stress during the curing process of the composite surface layer and preventing surface cracking due to excessive hydration heat. The fly ash is Grade I fly ash with a particle size of 5-20 μm, a water requirement ratio ≤95%, and an activity index ≥90% (28d), which can improve the density and durability of the surface layer.

[0018] In this invention, the pearl cotton particles are obtained by hydroxylation modification of recycled pearl cotton, with a particle size of 2-8 mm, a density of 20-30 kg / m³, and a surface hydroxyl content of 0.8-1.2 mmol / g. After modification, the compatibility with the resin matrix is ​​significantly improved. The pearl cotton short fibers are 3-8 mm in length, 50-100 μm in diameter, have an elongation at break ≥300%, a tensile strength ≥15 MPa, and a bond strength with cement-based cementitious materials ≥1.2 MPa. They can play a bridging and reinforcing role in the composite surface layer, reducing surface shrinkage cracks.

[0019] This invention also discloses a method for preparing a building exterior wall insulation board based on pearl cotton, comprising the following steps:

[0020] S1. Core layer preparation: First, add pearl cotton particles and silane coupling agent KH560 to a high-speed mixer in proportion and stir at 300-500 r / min for 10-20 minutes to make the coupling agent uniformly coat the particle surface; then add pretreated graphene-supported expanded graphite, nano silica aerogel, ammonium polyphosphate, pentaerythritol, melamine, ethylene-vinyl acetate copolymer, maleic anhydride grafted polyethylene, nano montmorillonite, silicon carbide whiskers, amino-terminated polyether, antioxidant 1010, and hindered amine light stabilizer 770. Heat to 40-50℃ and continue stirring at 300-500 r / min for 20-30 minutes to promote the esterification and crosslinking reaction of amino-terminated polyether and maleic anhydride grafted polyethylene to obtain a uniform and viscous core layer slurry;

[0021] S2. Surface preparation: Add cement-based cementitious materials, fly ash, and titanium dioxide to a mixing tank in proportion, and dry mix at a rate of 1000-1500 r / min for 5-10 minutes to ensure uniform mixing of dry materials; add deionized water and continue mixing at 1000-1500 r / min for 10-15 minutes to form a cement paste; then add hydroxypropyl methylcellulose ether, polyacrylonitrile fiber, pearl cotton short fiber, waterborne epoxy resin emulsion, silane-modified polyurethane emulsion, and defoamer, pre-mix at 1500 r / min for 5-8 minutes, and then high-speed shear at 2000-3000 r / min for 15-25 minutes to promote the cross-linking reaction of epoxy resin and polyurethane, and obtain a uniform and delicate surface slurry;

[0022] S3. Composite Molding: Prepare a cuboid mold, apply a release agent to the inner wall of the mold, and first evenly coat the bottom of the mold with a 1-3mm thick layer of surface slurry, smoothing it with a scraper; after the bottom layer of surface slurry has initially solidified, lay the core layer of slurry into the mold, controlling the thickness to 30-60mm. During the laying process, gently vibrate with a vibrator to remove air bubbles inside the core layer; after the core layer is laid, evenly coat the surface of the core layer with a 1-3mm thick layer of surface slurry, and smooth it again with a scraper; send the mold into the press, using a step-by-step pressurization method, first holding the pressure at 0.5MPa for 5 minutes, then increasing the pressure to 1.0-1.5MPa and holding it for 5-15 minutes to ensure a tight bond between the composite structures;

[0023] S4. Curing and Solidification: Remove the pressurized mold and place it in a room temperature curing chamber for 24-48 hours. The curing environment temperature is 20-25℃ and the humidity is 60-70%. After room temperature curing, remove the insulation board blank from the mold and send it to a steam curing kiln for steam curing. The curing temperature is 60-80℃ and the humidity is ≥90%. The curing time is 12-24 hours, and the heating rate is controlled at 5-10℃ / h to avoid structural cracking due to excessive heating. After steam curing, cool it down to room temperature at a cooling rate of 3-5℃ / h. Finally, microwave dry the insulation board with a microwave power of 500-800W for 20-30 minutes to make the moisture content of the insulation board ≤8%, thus obtaining the finished insulation board.

[0024] In this invention, the heating and stirring process in S1 is carried out in two stages. In the first stage, the temperature is raised to 40°C and stirred for 10 minutes to ensure sufficient contact between the amino-terminated polyether and the maleic anhydride-grafted polyethylene. In the second stage, the temperature is raised to 45-50°C and stirred for another 10-20 minutes to ensure that the esterification reaction reaches more than 70%. The uniformity of crosslinking is improved by controlling the temperature in stages. The pretreatment steps of graphene-supported expanded graphite in S1 are as follows: graphene-supported expanded graphite is added to an ethanol solution, silane coupling agent KH560 is added, the temperature is raised to 60°C and stirred for 2 hours, filtered, and then dried at 80°C for 4 hours to complete the modification.

[0025] In this invention, the vibrator in step S3 operates at a frequency of 20-30Hz for 3-5 minutes. During vibration, the vibrator probe penetrates no more than 10mm into the core slurry to avoid damaging the underlying surface layer structure. In step S4, microwave drying is performed intermittently, with a 5-minute pause after every 10 minutes of drying to prevent localized overheating and deformation of the insulation board. After drying, the insulation board undergoes dimensional inspection to ensure a shrinkage rate ≤0.5% and a surface flatness error ≤2mm / m, meeting construction requirements.

[0026] (iii) Beneficial technical effects

[0027] Compared with existing technologies, the beneficial effects of this invention are:

[0028] In terms of structural design, the "surface layer-core layer-surface layer" sandwich structure achieves functional complementarity. The core layer plays an excellent role in heat preservation and flame retardancy, while the composite surface layer provides reliable protection and structural support, avoiding the problem of performance imbalance in a single structure. In the core layer, the esterification reaction of amino-terminated polyether and maleic anhydride-grafted polyethylene constructs a three-dimensional cross-linked network. Combined with the reinforcing effect of silicon carbide whiskers, this significantly improves the structural stability and mechanical properties of the core layer, solving the pain points of traditional pearl cotton insulation boards in terms of weak compression resistance and impact resistance.

[0029] Component innovation brings about a comprehensive performance upgrade. Graphene-supported expanded graphite, modified with a coupling agent, exhibits significantly improved compatibility with the organic matrix. Combined with the ultra-low thermal conductivity of nano-silica aerogel, it constructs a highly efficient thermal insulation system with insulation performance far exceeding that of traditional products. Ammonium polyphosphate, pentaerythritol, and melamine form a synergistic flame-retardant system, and the barrier effect of the cross-linked network greatly enhances the flame-retardant effect. In the composite surface layer, the cross-linking reaction of epoxy resin and polyurethane forms a dense structure, while aluminum-coated titanium dioxide and modified polyacrylonitrile fibers improve weather resistance and crack resistance, effectively resisting aging and cracking caused by ultraviolet radiation and temperature changes, and solving the problems of easy damage and water seepage in the surface layer.

[0030] Optimization of the preparation process improves product quality and industrial adaptability. Segmented heating and stirring of the core layer ensures a thorough and uniform cross-linking reaction, while pre-dispersion and high-speed shearing of the surface layer promote component compatibility and cross-linking, avoiding agglomeration and uneven performance. Stepped pressurization and multi-stage curing processes reduce air bubbles and internal stress, and microwave drying controls moisture content and dimensional stability, improving product consistency and construction adaptability.

[0031] Furthermore, by using recycled pearl cotton as raw material, waste is recycled, achieving both economic and environmental value. Overall, this patented product possesses excellent thermal insulation, mechanical strength, flame retardancy, and durability. Its manufacturing process is highly efficient and controllable, providing a high-performance solution for building exterior wall insulation with broad application prospects. Attached Figure Description

[0032] Figure 1 This is a flowchart of the method for preparing building exterior wall insulation boards based on pearl cotton proposed in this invention;

[0033] Figure 2 It is a biaxial bar chart of thermal insulation and flame retardant performance;

[0034] Appendix Figure 3 Line graph of mechanical properties;

[0035] Appendix Figure 4 : A diagram showing the combination of durability and environmental performance. Detailed Implementation

[0036] according to Figures 1 to 4 The specific embodiments of the present invention are as follows:

[0037] A building exterior wall insulation board based on pearl cotton includes a core layer and a composite surface layer. The core layer is laminated with a composite surface layer on both sides, forming a "surface layer-core layer-surface layer" sandwich structure.

[0038] The core layer raw materials, by weight, are: 40-60 parts pearl cotton particles, 5-15 parts graphene-supported expanded graphite, 3-10 parts nano-silica aerogel, 10-20 parts ammonium polyphosphate, 5-12 parts pentaerythritol, 3-8 parts melamine, 15-25 parts ethylene-vinyl acetate copolymer, 5-10 parts maleic anhydride-grafted polyethylene, 2-6 parts nano-montmorillonite, 1-5 parts silicon carbide whiskers, 0.5-2 parts silane coupling agent KH560, 0.2-0.8 parts antioxidant 1010, 3-8 parts amino-terminated polyether, and 0.3-1 parts hindered amine light stabilizer 770.

[0039] The composite surface layer raw materials, by weight, are: 30-50 parts cement-based cementitious materials, 8-15 parts pearl cotton short fibers, 10-20 parts fly ash, 2-5 parts hydroxypropyl methylcellulose ether, 1-4 parts polyacrylonitrile fibers, 2-6 parts titanium dioxide, 5-12 parts waterborne epoxy resin emulsion, 3-8 parts silane-modified polyurethane emulsion, 0.1-0.5 parts defoamer, and 15-25 parts deionized water.

[0040] During the core layer preparation process, amino-terminated polyether and maleic anhydride-grafted polyethylene undergo an esterification reaction. The reaction formula is maleic anhydride-grafted polyethylene-COOH + amino-terminated polyether-NH2 → maleic anhydride-grafted polyethylene-CO-NH-polyether + H2O. This reaction constructs a three-dimensional cross-linked network, improving the structural stability of the core layer. In the composite surface layer, waterborne epoxy resin emulsion and silane-modified polyurethane emulsion undergo a cross-linking reaction to form a dense structure, enhancing the protective performance of the surface layer.

[0041] This invention also includes the modification of the graphene-supported expanded graphite in the core layer by pretreatment with the silane coupling agent KH560. During the modification process, an interfacial coupling reaction occurs, with the reaction formula being KH560-Si(OCH3)3 + graphene-supported expanded graphite-OH → KH560-Si(OCH3)2-O-graphite + CH3OH. After modification, the hydroxyl content on the surface of the graphene-supported expanded graphite decreases to 0.3-0.6 mmol / g, the compatibility with organic components such as ethylene-vinyl acetate copolymer is improved by more than 40%, the dispersion uniformity is significantly improved, and fluctuations in thermal conductivity caused by agglomeration are avoided.

[0042] This invention also includes a crosslinking reaction between the waterborne epoxy resin emulsion and the silane-modified polyurethane emulsion in the composite surface layer, which must be fully carried out during shearing and stirring, achieving a crosslinking degree of 60-80%. The titanium dioxide is treated with an aluminum coating process, with a coating thickness of 5-15 nm. After coating treatment, the weather resistance of the titanium dioxide is improved by more than 30%, effectively resisting surface aging and yellowing caused by ultraviolet radiation. The polyacrylonitrile fiber is modified, with a surface hydroxylation treatment and a hydroxyl content of 1.0-1.5 mmol / g, increasing the bonding strength with cement-based cementitious materials by 60% and enhancing the crack resistance of the surface layer.

[0043] In this invention, the nano-silica aerogel is modified with methyltriethoxysilane, with a particle size of 20-50 nm, a specific surface area of ​​600-800 m² / g, a porosity of 85-95%, and a thermal conductivity ≤0.025 W / (m·K). After modification with methyltriethoxysilane, the hydrophobic contact angle of the aerogel surface is ≥120°, and the hygroscopicity is reduced to below 5%, effectively avoiding the problem of decreased thermal insulation performance after moisture absorption in traditional aerogels, and making it suitable for high-humidity building environments.

[0044] In this invention, the silicon carbide whiskers have an aspect ratio of 15-30:1, a diameter of 50-200 nm, a length of 1-5 μm, a purity of ≥98%, a tensile strength of ≥3 GPa, and an elastic modulus of ≥400 GPa. The silicon carbide whiskers require pretreatment with γ-aminopropyltriethoxysilane. After pretreatment, the surface amino content is 1.2-1.8 mmol / g, increasing the bonding strength with the ethylene-vinyl acetate copolymer matrix by more than 50%, forming a "fiber-reinforced" structure in the core layer, significantly improving the core layer's compressive strength and impact resistance.

[0045] In this invention, the cement-based cementitious material is a mixture of ordinary Portland cement and sulfoaluminate cement in a mass ratio of 3:1-2:1, with both cement grades ≥42.5R. The sulfoaluminate cement has an initial setting time of 15-30 min and a final setting time of 60-90 min, with a hydration heat peak reduced to below 200 J / g, effectively reducing temperature stress during the curing process of the composite surface layer and preventing surface cracking due to excessive hydration heat. The fly ash is Grade I fly ash with a particle size of 5-20 μm, a water requirement ratio ≤95%, and an activity index ≥90% (28d), which can improve the density and durability of the surface layer.

[0046] In this invention, the pearl cotton particles are obtained by hydroxylation modification of recycled pearl cotton, with a particle size of 2-8 mm, a density of 20-30 kg / m³, and a surface hydroxyl content of 0.8-1.2 mmol / g. After modification, the compatibility with the resin matrix is ​​significantly improved. The pearl cotton short fibers are 3-8 mm in length, 50-100 μm in diameter, have an elongation at break ≥300%, a tensile strength ≥15 MPa, and a bond strength with cement-based cementitious materials ≥1.2 MPa. They can play a bridging and reinforcing role in the composite surface layer, reducing surface shrinkage cracks.

[0047] This invention also discloses a method for preparing a building exterior wall insulation board based on pearl cotton, comprising the following steps:

[0048] S1. Core layer preparation: First, add pearl cotton particles and silane coupling agent KH560 to a high-speed mixer in proportion and stir at 300-500 r / min for 10-20 minutes to make the coupling agent uniformly coat the particle surface; then add pretreated graphene-supported expanded graphite, nano silica aerogel, ammonium polyphosphate, pentaerythritol, melamine, ethylene-vinyl acetate copolymer, maleic anhydride grafted polyethylene, nano montmorillonite, silicon carbide whiskers, amino-terminated polyether, antioxidant 1010, and hindered amine light stabilizer 770. Heat to 40-50℃ and continue stirring at 300-500 r / min for 20-30 minutes to promote the esterification and crosslinking reaction of amino-terminated polyether and maleic anhydride grafted polyethylene to obtain a uniform and viscous core layer slurry;

[0049] S2. Surface preparation: Add cement-based cementitious materials, fly ash, and titanium dioxide to a mixing tank in proportion, and dry mix at a rate of 1000-1500 r / min for 5-10 minutes to ensure uniform mixing of dry materials; add deionized water and continue mixing at 1000-1500 r / min for 10-15 minutes to form a cement paste; then add hydroxypropyl methylcellulose ether, polyacrylonitrile fiber, pearl cotton short fiber, waterborne epoxy resin emulsion, silane-modified polyurethane emulsion, and defoamer, pre-mix at 1500 r / min for 5-8 minutes, and then high-speed shear at 2000-3000 r / min for 15-25 minutes to promote the cross-linking reaction of epoxy resin and polyurethane, and obtain a uniform and delicate surface slurry;

[0050] S3. Composite Molding: Prepare a cuboid mold, apply a release agent to the inner wall of the mold, and first evenly coat the bottom of the mold with a 1-3mm thick layer of surface slurry, smoothing it with a scraper; after the bottom layer of surface slurry has initially solidified, lay the core layer of slurry into the mold, controlling the thickness to 30-60mm. During the laying process, gently vibrate with a vibrator to remove air bubbles inside the core layer; after the core layer is laid, evenly coat the surface of the core layer with a 1-3mm thick layer of surface slurry, and smooth it again with a scraper; send the mold into the press, using a step-by-step pressurization method, first holding the pressure at 0.5MPa for 5 minutes, then increasing the pressure to 1.0-1.5MPa and holding it for 5-15 minutes to ensure a tight bond between the composite structures;

[0051] S4. Curing and Solidification: Remove the pressurized mold and place it in a room temperature curing chamber for 24-48 hours. The curing environment temperature is 20-25℃ and the humidity is 60-70%. After room temperature curing, remove the insulation board blank from the mold and send it to a steam curing kiln for steam curing. The curing temperature is 60-80℃ and the humidity is ≥90%. The curing time is 12-24 hours, and the heating rate is controlled at 5-10℃ / h to avoid structural cracking due to excessive heating. After steam curing, cool it down to room temperature at a cooling rate of 3-5℃ / h. Finally, microwave dry the insulation board with a microwave power of 500-800W for 20-30 minutes to make the moisture content of the insulation board ≤8%, thus obtaining the finished insulation board.

[0052] In this invention, the heating and stirring process in S1 is carried out in two stages. In the first stage, the temperature is raised to 40°C and stirred for 10 minutes to ensure sufficient contact between the amino-terminated polyether and the maleic anhydride-grafted polyethylene. In the second stage, the temperature is raised to 45-50°C and stirred for another 10-20 minutes to ensure that the esterification reaction reaches more than 70%. The uniformity of crosslinking is improved by controlling the temperature in stages. The pretreatment steps of graphene-supported expanded graphite in S1 are as follows: graphene-supported expanded graphite is added to an ethanol solution, silane coupling agent KH560 is added, the temperature is raised to 60°C and stirred for 2 hours, filtered, and then dried at 80°C for 4 hours to complete the modification.

[0053] In this invention, the vibrator in step S3 operates at a frequency of 20-30Hz for 3-5 minutes. During vibration, the vibrator probe penetrates no more than 10mm into the core slurry to avoid damaging the underlying surface layer structure. In step S4, microwave drying is performed intermittently, with a 5-minute pause after every 10 minutes of drying to prevent localized overheating and deformation of the insulation board. After drying, the insulation board undergoes dimensional inspection to ensure a shrinkage rate ≤0.5% and a surface flatness error ≤2mm / m, meeting construction requirements.

[0054] Example 1

[0055] Raw material preparation

[0056] Core layer raw materials: 40 parts of pearl cotton granules, which are obtained by hydroxylation modification of recycled pearl cotton, with a particle size of 2-4 mm, a density of 20-25 kg / m³, and a surface hydroxyl content of 0.8-1.0 mmol / g; 5 parts of graphene-supported expanded graphite, which is pretreated and modified with silane coupling agent KH560 (graphene-supported expanded graphite is added to an ethanol solution, KH560 is added in the corresponding proportion, the temperature is raised to 60℃ and stirred for 2 hours, filtered, and then dried at 80℃ for 4 hours); 3 parts of nano-silica aerogel, which is methyltriethoxysilane modified, with a particle size of 20-30 nm, a specific surface area of ​​600-650 m² / g, a porosity of 85-88%, and a thermal conductivity ≤0.025 W. / (m·K), surface hydrophobic contact angle ≥120°; 10 parts ammonium polyphosphate; 5 parts pentaerythritol; 3 parts melamine; 15 parts ethylene-vinyl acetate copolymer; 5 parts maleic anhydride grafted polyethylene; 2 parts nano montmorillonite; 1 part silicon carbide whiskers, aspect ratio 15-20:1, diameter 50-100nm, length 1-2μm, purity ≥98%, tensile strength ≥3GPa, elastic modulus ≥400GPa, pretreated with γ-aminopropyltriethoxysilane, surface amino content 1.2-1.4mmol / g; 0.5 parts silane coupling agent KH560; 0.2 parts antioxidant 10100; 3 parts amino-terminated polyether; 0.3 parts hindered amine light stabilizer 7700.

[0057] Composite surface layer raw materials: 30 parts of cement-based cementitious material, which is a mixture of ordinary Portland cement and sulfoaluminate cement in a mass ratio of 3:1, with both cement grades ≥42.5R. The sulfoaluminate cement has an initial setting time of 15-20 min, a final setting time of 60-70 min, and a peak hydration heat ≤200 J / g; 8 parts of pearl cotton short fibers, with a length of 3-5 mm, a diameter of 50-70 μm, an elongation at break ≥300%, a tensile strength ≥15 MPa, and a bond strength with the cement-based cementitious material ≥ 1.2 MPa; 10 parts fly ash, Class I fly ash, particle size 5-10 μm, water requirement ≤95%, activity index ≥90% (28d); 2 parts hydroxypropyl methylcellulose ether; 1 part polyacrylonitrile fiber, modified type, surface hydroxylated, hydroxyl content 1.0-1.2 mmol / g; 2 parts titanium dioxide, treated with aluminum coating process, coating layer thickness 5-8 nm; 5 parts waterborne epoxy resin emulsion; 3 parts silane-modified polyurethane emulsion; 0.1 parts defoamer; 15 parts deionized water.

[0058] Preparation process

[0059] Core layer preparation: First, add 40 parts of pearl cotton granules and 0.5 parts of silane coupling agent KH560 to a high-speed mixer and stir at 300 r / min for 20 minutes to ensure that the coupling agent uniformly coats the surface of the granules. Then, add 5 parts of pretreated graphene-supported expanded graphite and other core layer raw materials, and start the heating program. In the first stage, heat to 40°C and maintain this temperature while stirring for 10 minutes to ensure that the amino-terminated polyether and maleic anhydride-grafted polyethylene are in full contact. In the second stage, heat to 45°C and continue stirring at 300 r / min for 20 minutes to ensure that the degree of esterification reaction reaches more than 70% and obtain a uniform and viscous core layer slurry.

[0060] Surface layer preparation: Add 30 parts of cement-based cementitious material, 10 parts of fly ash, and 2 parts of titanium dioxide to a mixing tank and dry mix at 1000 rpm for 10 minutes to ensure uniform mixing. Add 15 parts of deionized water and continue mixing at 1000 rpm for 15 minutes to form a cement paste. Then add 2 parts of hydroxypropyl methylcellulose ether, 1 part of polyacrylonitrile fiber, 8 parts of pearl cotton short fiber, 5 parts of waterborne epoxy resin emulsion, 3 parts of silane-modified polyurethane emulsion, and 0.1 parts of defoamer. Pre-mix at 1500 rpm for 8 minutes, then shear at 2000 rpm for 25 minutes to ensure that the crosslinking degree of the waterborne epoxy resin emulsion and the silane-modified polyurethane emulsion reaches more than 60%, resulting in a uniform and fine surface layer slurry.

[0061] Composite Molding: Prepare a rectangular mold, evenly coat the inner wall of the mold with release agent, and first evenly coat the bottom of the mold with a 1mm thick surface layer slurry, smoothing it with a scraper. After the bottom surface layer slurry has initially set, lay the core layer slurry into the mold, controlling the thickness to 30mm. During the laying process, gently vibrate with a vibrator at a frequency of 20Hz for 5 minutes, ensuring the vibrator probe penetrates no more than 10mm into the core layer slurry to remove air bubbles. After the core layer is laid, evenly coat the surface of the core layer with a 1mm thick surface layer slurry and smooth it again with a scraper. Send the mold into the press, using a step-by-step pressurization method, first holding the pressure at 0.5MPa for 5 minutes, then increasing to 1.0MPa and holding for 15 minutes to ensure a tight bond between the composite structures.

[0062] Curing and solidification: The pressurized mold is removed and placed in a room temperature curing chamber for 48 hours at 20℃ and 60% humidity. After room temperature curing, the insulation board blank is removed from the mold and sent to a steam curing kiln for 24 hours at 60℃ and ≥90% humidity, with a heating rate controlled at 5℃ / h. After steam curing, it is cooled to room temperature at a rate of 3℃ / h. Finally, the insulation board is subjected to intermittent microwave drying at a microwave power of 500W, with a 5-minute stop after every 10 minutes of drying, for a total drying time of 30 minutes, ensuring the moisture content of the insulation board is ≤8%. After drying, the dimensional shrinkage rate is ≤0.5%, and the surface flatness error is ≤2mm / m, yielding the finished insulation board.

[0063] Example 2

[0064] Raw material preparation

[0065] Core layer raw materials: 50 parts of pearl cotton granules, obtained by hydroxylation modification of recycled pearl cotton, with a particle size of 4-6 mm, density of 23-27 kg / m³, and surface hydroxyl content of 1.0-1.1 mmol / g; 10 parts of graphene-supported expanded graphite, pretreated and modified with silane coupling agent KH560; 6 parts of nano-silica aerogel, modified with methyltriethoxysilane, with a particle size of 30-40 nm, specific surface area of ​​650-700 m² / g, porosity of 88-92%, thermal conductivity ≤0.025 W / (m·K), and surface hydrophobic contact angle ≥120°. °; 15 parts ammonium polyphosphate; 8 parts pentaerythritol; 5 parts melamine; 20 parts ethylene-vinyl acetate copolymer; 7 parts maleic anhydride-grafted polyethylene; 4 parts nano-montmorillonite; 3 parts silicon carbide whiskers, aspect ratio 20-25:1, diameter 100-150nm, length 2-3μm, purity ≥98%, pretreated with γ-aminopropyltriethoxysilane, surface amino content 1.4-1.6mmol / g; 1.2 parts silane coupling agent KH560; 0.5 parts antioxidant 1010; 5 parts amino-terminated polyether; 0.6 parts hindered amine light stabilizer 770.

[0066] Composite surface layer raw materials: 40 parts of cement-based cementitious material, which is a mixture of ordinary Portland cement and sulfoaluminate cement at a mass ratio of 2.5:1, with both cement grades ≥42.5R. The initial setting time of the sulfoaluminate cement is 20-25 min, the final setting time is 70-80 min, and the peak heat of hydration is ≤200 J / g; 12 parts of pearl cotton short fibers, with a length of 5-6 mm, a diameter of 70-80 μm, an elongation at break ≥300%, a tensile strength ≥15 MPa, and a bond strength with the cement-based cementitious material ≥1. 2 MPa; 15 parts fly ash, Class I fly ash, particle size 10-15 μm, water requirement ≤95%, activity index ≥90% (28d); 3 parts hydroxypropyl methylcellulose ether; 2 parts polyacrylonitrile fiber, modified type, surface hydroxylated, hydroxyl content 1.2-1.3 mmol / g; 4 parts titanium dioxide, treated with aluminum coating process, coating layer thickness 8-12 nm; 8 parts waterborne epoxy resin emulsion; 5 parts silane-modified polyurethane emulsion; 0.3 parts defoamer; 20 parts deionized water.

[0067] Preparation process

[0068] Core layer preparation: First, add 50 parts of pearl cotton granules and 1.2 parts of silane coupling agent KH560 to a high-speed mixer and stir at 400 r / min for 15 minutes to ensure that the coupling agent uniformly coats the surface of the granules. Then, add 10 parts of pretreated graphene-supported expanded graphite and other core layer raw materials, and start the heating program. The first stage heats up to 40℃ and maintains this temperature while stirring for 10 minutes; the second stage heats up to 47℃ and continues to stir at 400 r / min for 15 minutes to ensure that the degree of esterification reaction reaches more than 70%, resulting in a uniform and viscous core layer slurry.

[0069] Surface layer preparation: Add 40 parts of cement-based cementitious material, 15 parts of fly ash, and 4 parts of titanium dioxide to a mixing tank and dry mix at 1200 rpm for 8 minutes to ensure uniform mixing. Add 20 parts of deionized water and continue mixing at 1200 rpm for 12 minutes to form a cement paste. Then add 3 parts of hydroxypropyl methylcellulose ether, 2 parts of polyacrylonitrile fiber, 12 parts of pearl cotton short fiber, 8 parts of waterborne epoxy resin emulsion, 5 parts of silane-modified polyurethane emulsion, and 0.3 parts of defoamer. Pre-mix at 1500 rpm for 6 minutes, then shear at 2500 rpm for 20 minutes to ensure a crosslinking degree of over 70%, resulting in a uniform and fine surface layer slurry.

[0070] Composite Molding: Prepare a rectangular mold, apply a release agent to the inner wall of the mold, and first evenly apply a 2mm thick layer of surface slurry to the bottom of the mold, smoothing it with a scraper. After the bottom layer of surface slurry has initially set, lay a 30-60mm thick core layer of slurry, and vibrate it for 4 minutes at a frequency of 25Hz using a vibrator, with the probe penetrating no more than 10mm. After the core layer is laid, apply a 2mm thick layer of surface slurry and smooth it. Send the mold into the press, first hold it at 0.5MPa for 5 minutes, then increase the pressure to 1.2MPa and hold it for 10 minutes.

[0071] Curing and hardening: The mold is placed in a room temperature curing chamber at 23℃ and 65% humidity for 36 hours. After demolding, it is placed in a steam curing kiln and cured for 18 hours at 70℃ and ≥90% humidity, with a heating rate of 8℃ / h. After steam curing, it is cooled to room temperature at a rate of 4℃ / h and then dried intermittently using a 600W microwave for 25 minutes to achieve a moisture content of ≤8%. After drying, the dimensional shrinkage rate and surface flatness are tested. If they meet the construction requirements, the finished product is obtained.

[0072] Example 3

[0073] Raw material preparation

[0074] Core layer raw materials: 60 parts of pearl cotton granules, obtained by hydroxylation modification of recycled pearl cotton, with a particle size of 6-8 mm, density of 25-30 kg / m³, and surface hydroxyl content of 1.1-1.2 mmol / g; 15 parts of graphene-supported expanded graphite, pretreated and modified with silane coupling agent KH560; 10 parts of nano-silica aerogel, modified with methyltriethoxysilane, with a particle size of 40-50 nm, specific surface area of ​​700-800 m² / g, porosity of 92-95%, thermal conductivity ≤0.025 W / (m·K), and surface hydrophobic contact angle ≥12°. 0°; 20 parts ammonium polyphosphate; 12 parts pentaerythritol; 8 parts melamine; 25 parts ethylene-vinyl acetate copolymer; 10 parts maleic anhydride-grafted polyethylene; 6 parts nano montmorillonite; 5 parts silicon carbide whiskers, aspect ratio 25-30:1, diameter 150-200nm, length 3-5μm, purity ≥98%, pretreated with γ-aminopropyltriethoxysilane, surface amino content 1.6-1.8mmol / g; 2 parts silane coupling agent KH560; 0.8 parts antioxidant 10100; 8 parts amino-terminated polyether; 1 part hindered amine light stabilizer 770.

[0075] Composite surface layer raw materials: 50 parts of cement-based cementitious material, which is a mixture of ordinary Portland cement and sulfoaluminate cement in a mass ratio of 2:1. Both cement grades are ≥42.5R. The initial setting time of sulfoaluminate cement is 25-30 min, the final setting time is 80-90 min, and the peak heat of hydration is ≤200 J / g; 15 parts of pearl cotton short fibers, with a length of 6-8 mm, a diameter of 80-100 μm, an elongation at break of ≥300%, a tensile strength of ≥15 MPa, and a bond strength with cement-based cementitious material of ≥1. 2MPa; 20 parts fly ash, Class I fly ash, particle size 15-20μm, water requirement ≤95%, activity index ≥90% (28d); 5 parts hydroxypropyl methylcellulose ether; 4 parts polyacrylonitrile fiber, modified type, surface hydroxylated, hydroxyl content 1.3-1.5mmol / g; 6 parts titanium dioxide, treated with aluminum coating process, coating layer thickness 12-15nm; 12 parts waterborne epoxy resin emulsion; 8 parts silane-modified polyurethane emulsion; 0.5 parts defoamer; 25 parts deionized water.

[0076] Preparation process

[0077] Core layer preparation: First, add 60 parts of pearl cotton granules and 2 parts of silane coupling agent KH560 to a high-speed mixer and stir at 500 r / min for 10 minutes to ensure that the coupling agent uniformly coats the surface of the granules. Then, add 15 parts of pretreated graphene-supported expanded graphite and other core layer raw materials, and start the heating program. The first stage heats up to 40°C and stirs for 10 minutes; the second stage heats up to 50°C and continues to stir at 500 r / min for 10 minutes to ensure that the degree of esterification reaction reaches more than 70% and obtain a uniform and viscous core layer slurry.

[0078] Surface layer preparation: Add 50 parts of cement-based cementitious material, 20 parts of fly ash, and 6 parts of titanium dioxide to a mixing tank and dry mix at 1500 rpm for 5 minutes to ensure uniform mixing. Add 25 parts of deionized water and continue mixing at 1500 rpm for 10 minutes to form a cement paste. Then add 5 parts of hydroxypropyl methylcellulose ether, 4 parts of polyacrylonitrile fiber, 15 parts of pearl cotton short fiber, 12 parts of waterborne epoxy resin emulsion, 8 parts of silane-modified polyurethane emulsion, and 0.5 parts of defoamer. Pre-mix at 1500 rpm for 5 minutes, then shear at 3000 rpm for 15 minutes to ensure a crosslinking degree of over 80%, resulting in a uniform and fine surface layer slurry.

[0079] Composite Molding: Prepare a rectangular mold, apply a release agent to the inner wall of the mold, and first evenly apply a 3mm thick layer of surface slurry to the bottom of the mold, smoothing it with a scraper. After the bottom layer of surface slurry has initially set, lay a 60mm thick core layer of slurry, and use a vibrator to vibrate at a frequency of 30Hz for 3 minutes, with the probe penetrating no more than 10mm. After the core layer is laid, apply a 3mm thick layer of surface slurry and smooth it. Send the mold into the press, first hold the pressure at 0.5MPa for 5 minutes, then increase the pressure to 1.5MPa and hold it for 5 minutes.

[0080] Curing and hardening: Place the mold in a room temperature curing chamber at 25℃ and 70% humidity for 24 hours. After demolding, transfer it to a steam curing kiln and cure it at 80℃ and ≥90% humidity for 12 hours, with a heating rate of 10℃ / h. After steam curing, cool it to room temperature at 5℃ / h and then use an 800W microwave intermittent drying method for 20 minutes to achieve a moisture content of ≤8%. After drying, check the dimensional shrinkage rate and surface flatness. If they meet the construction requirements, the finished product is obtained.

[0081] Comparative Example

[0082] Raw material preparation

[0083] Core layer raw materials: 50 parts of unmodified virgin pearl cotton particles, particle size 4-6mm, density 23-27kg / m³; 10 parts of ordinary expanded graphite (without silane coupling agent KH560 pretreatment); 6 parts of ordinary silica powder (unmodified, particle size 100-200nm); 15 parts of ammonium polyphosphate; 20 parts of ethylene-vinyl acetate copolymer; 4 parts of nano-montmorillonite; 0.5 parts of antioxidant 10100.

[0084] Composite surface layer raw materials (by weight): 40 parts ordinary silicate cement (grade ≥42.5R); 15 parts fly ash (Grade II fly ash, particle size 20-30μm, water requirement ratio 100-110%, activity index 28d 80-85%); 3 parts hydroxypropyl methylcellulose ether; 2 parts ordinary polyacrylonitrile fiber (unmodified, no hydroxyl groups on the surface); 4 parts titanium dioxide (uncoated); 20 parts deionized water.

[0085] Preparation process

[0086] Core layer preparation: All core layer raw materials were directly added to the mixer and stirred at 400 r / min for 25 minutes. The mixture was homogeneous at room temperature without staged heating or cross-linking reaction control, resulting in core layer slurry.

[0087] Surface layer preparation: Cement, fly ash, and titanium dioxide are added to a mixing tank and dry-mixed at 1200 r / min for 8 minutes. Deionized water is added and mixed for 12 minutes to form a cement paste. Other surface layer materials are then added and mixed at 1500 r / min for 20 minutes. No high-speed shearing treatment is performed to obtain the surface layer slurry.

[0088] Composite molding: Prepare a rectangular mold, apply a release agent to the inner wall, first apply a 2mm thick surface layer slurry, smooth it out, and then directly lay the core layer slurry (40mm thick) without vibration treatment, followed by another 2mm thick surface layer slurry. Send the mold into the press and hold it at 1.2MPa pressure for 15 minutes at a time.

[0089] Curing and solidification: The mold is placed in a normal temperature environment (temperature 18-25℃, natural humidity) for 72 hours. After demolding, no steam curing or microwave drying is performed. The mold is simply air-dried until the surface is dry to obtain the finished insulation board.

[0090] The following table compares the thermal insulation and mechanical properties of the examples and comparative examples:

[0091] Table 1

[0092]

[0093] This table focuses on the differences in the core functional performance of the insulation board, clearly demonstrating the optimization effect of this patented technology. Regarding thermal conductivity, the low value of 0.025-0.030 W / (m·K) in the examples stems from the ultra-low thermal conductivity of the nano-silica aerogel and the synergistic insulation effect of graphene-supported expanded graphite. After modification with a coupling agent, both are uniformly dispersed, constructing a continuous insulation barrier. The high thermal conductivity of 0.050 W / (m·K) in the comparative example is due to the lack of efficient insulation filler and the unmodified agglomeration of graphite, resulting in broken insulation pathways. In terms of mechanical properties, the compressive strength of 0.3-0.5 MPa and the impact strength of 2.5-3.5 kJ / m² in the examples benefit from the cross-linked network formed by the amino-terminated polyether and maleic anhydride-grafted polyethylene in the core layer, combined with the reinforcing effect of silicon carbide whiskers. The low performance of 0.15 MPa and 1.0 kJ / m² in the comparative example is due to the lack of chemical cross-linking and reinforcing components, resulting in a loose structure that is easily damaged. The difference in oxygen index reflects the synergistic effect of the flame retardant system. The example has an oxygen index of 30%-35% that meets the B1 grade requirement, while the comparative example has an oxygen index of 25% that only reaches the B2 grade, highlighting the value of component innovation.

[0094] The following table compares the durability and process performance of the examples and comparative examples:

[0095] Table 2

[0096]

[0097] This table reflects the key performance differences of the insulation board during long-term use and preparation, highlighting the practical advantages of this patented technology. Regarding bonding strength, the 0.15-0.20 MPa performance of the Example is due to the cross-linking structure of the waterborne epoxy resin and silane-modified polyurethane in the composite surface layer, as well as the interface adaptation design between the surface layer and the core layer. The low strength of 0.05 MPa in the Comparative Example is due to the surface layer being a single cement-based material, resulting in poor compatibility with the core layer and easy delamination. In terms of weather resistance, the stable performance of the Example without cracking after 500 hours is attributed to the UV resistance of the aluminum-coated titanium dioxide and the crack resistance enhancement of the polyacrylonitrile fiber. The Comparative Example cracked after 500 hours due to the lack of weather-resistant components and crack-resistant design, making it unable to withstand outdoor environmental erosion. The difference in dimensional shrinkage and moisture content is attributed to the precise control of the multi-stage curing and microwave drying process in the Example, while the Comparative Example was only cured at room temperature, resulting in uneven moisture evaporation and significant structural shrinkage, affecting post-construction stability.

[0098] The following table compares the flame retardant and thermal stability performance of the examples and comparative examples:

[0099] Table 3

[0100]

[0101] This table provides an in-depth analysis of the safety performance and thermal stability of the insulation board, highlighting the safety advantages of this patented technology. Regarding flame retardant performance, all examples achieve a V-0 rating with a smoke density of only 25-35. The core of this is the intumescent flame retardant system formed by ammonium polyphosphate, pentaerythritol, and melamine. During combustion, it generates a dense char layer that blocks oxygen and heat, and, combined with the structural support of the cross-linked network, inhibits flame spread and smoke release. In contrast, the comparative examples, with a V-2 rating and a smoke density of 75, lack a synergistic flame retardant design, resulting in melting and dripping during combustion and a large amount of smoke, posing a serious safety hazard. In terms of thermal stability, the examples exhibit a heat distortion temperature of 85-95℃ and a thermal weight loss rate of 2.5%-3.2% at 200℃, thanks to the cross-linked network enhancing the heat resistance of the molecular chains, while antioxidants and light stabilizers delay thermal aging. The comparative examples, with a heat distortion temperature of 60℃ and a thermal weight loss of 12.6%, suffer from a loose molecular structure and lack of thermally stabilizing components, making them prone to softening and degradation at high temperatures and unsuitable for high-temperature environments.

[0102] The following table compares the construction compatibility and environmental performance of the examples and comparative examples:

[0103] Table 4

[0104]

[0105] This table reveals the engineering application adaptability and environmental friendliness of the insulation board, reflecting the comprehensive value of this patented technology. Regarding construction adaptability, the areal density of Example 18-22 kg / m² is lower than that of the comparative example (25 kg / m²), reducing the load-bearing pressure on the wall and facilitating on-site installation. The water absorption rate of less than 4.5% is reduced due to the hydrophobic modification of the nano-silica aerogel and the dense structure of the surface layer, minimizing weight increase and performance degradation caused by water absorption. In contrast, the high water absorption rate of 12.8% in the comparative example easily leads to bulging and detachment of the insulation layer. In terms of sound insulation performance, the sound insulation of Example 32-38 dB is due to the porous structure of the core layer and the sound energy blocking effect of the composite surface layer. The low sound insulation of 25 dB in the comparative example is limited due to its simple structure and insufficient density. In terms of environmental performance, the embodiment has a recycling rate of 35%-55%, which realizes the resource utilization of waste by recycling and modifying pearl cotton and reusing it, thus reducing the environmental burden; the comparative embodiment has a zero recycling rate, which does not meet the needs of green building materials development, highlighting the dual economic and environmental benefits of this patented technology.

[0106] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A building exterior wall insulation board based on pearl cotton, characterized in that, It includes a core layer and a composite surface layer, with composite surface layers on both sides of the core layer, forming a sandwich structure; The core layer raw materials, by weight, are: 40-60 parts pearl cotton particles, 5-15 parts graphene-supported expanded graphite, 3-10 parts nano-silica aerogel, 10-20 parts ammonium polyphosphate, 5-12 parts pentaerythritol, 3-8 parts melamine, 15-25 parts ethylene-vinyl acetate copolymer, 5-10 parts maleic anhydride-grafted polyethylene, 2-6 parts nano-montmorillonite, 1-5 parts silicon carbide whiskers, 0.5-2 parts silane coupling agent KH560, 0.2-0.8 parts antioxidant 1010, 3-8 parts amino-terminated polyether, and 0.3-1 parts hindered amine light stabilizer 770. The composite surface layer raw materials, by weight, are: 30-50 parts cement-based cementitious materials, 8-15 parts pearl cotton short fibers, 10-20 parts fly ash, 2-5 parts hydroxypropyl methylcellulose ether, 1-4 parts polyacrylonitrile fibers, 2-6 parts titanium dioxide, 5-12 parts waterborne epoxy resin emulsion, 3-8 parts silane-modified polyurethane emulsion, 0.1-0.5 parts defoamer, and 15-25 parts deionized water. The graphene-supported expanded graphite in the core layer needs to be pretreated and modified by silane coupling agent KH560. During the modification process, an interfacial coupling reaction occurs, and the reaction formula is KH560-Si(OCH3)3+graphene-supported expanded graphite-OH→KH560-Si(OCH3)2-O-graphene-supported expanded graphite+CH3OH. The nano-silica aerogel is modified with methyltriethoxysilane, with a particle size of 20-50 nm and a specific surface area of ​​600-800 m². 2 / g, porosity 85-95%, thermal conductivity ≤0.025W / (m·K); after modification with methyltriethoxysilane, the hydrophobic contact angle of the aerogel surface is ≥120°; Silicon carbide whiskers have an aspect ratio of 15-30:1, a diameter of 50-200 nm, a length of 1-5 μm, a purity of ≥98%, a tensile strength of ≥3 GPa, and an elastic modulus of ≥400 GPa. The silicon carbide whiskers need to be pretreated with γ-aminopropyltriethoxysilane, and the surface amino content after pretreatment is 1.2-1.8 mmol / g. Pearl cotton granules are obtained by hydroxylation modification of recycled pearl cotton, with a particle size of 2-8 mm and a density of 20-30 kg / m³. 3 The surface hydroxyl content is 0.8-1.2 mmol / g, the short fiber length of pearl cotton is 3-8 mm, the diameter is 50-100 μm, the elongation at break is ≥300%, the tensile strength is ≥15 MPa, and the bond strength with cement-based cementitious materials is ≥1.2 MPa. The crosslinking reaction between the waterborne epoxy resin emulsion and the silane-modified polyurethane emulsion in the composite surface layer needs to be fully carried out during the shearing and stirring process, with a crosslinking degree of 60-80%. The titanium dioxide is treated with an aluminum coating process, with a coating layer thickness of 5-15nm. The polyacrylonitrile fiber is modified and its surface is hydroxylated, with a hydroxyl content of 1.0-1.5mmol / g.

2. The building exterior wall insulation board based on pearl cotton according to claim 1, characterized in that, The cement-based cementitious material is a mixture of ordinary Portland cement and sulfoaluminate cement in a mass ratio of 3:1-2:

1. Both types of cement have a grade ≥42.5R. The initial setting time of the sulfoaluminate cement is 15-30 min, the final setting time is 60-90 min, and the peak heat of hydration is reduced to below 200 J / g. The fly ash is Grade I fly ash with a particle size of 5-20 μm, a water requirement ratio ≤95%, and an activity index ≥90% at 28d.

3. A method for preparing a building exterior wall insulation board based on pearl cotton, used to prepare the building exterior wall insulation board based on pearl cotton as described in any one of claims 1-2, characterized in that, Includes the following steps: S1. Core layer preparation: First, add pearl cotton particles and silane coupling agent KH560 to a mixer in proportion and stir at a speed of 300-500 r / min for 10-20 minutes to make the coupling agent uniformly coat the particle surface; then add pretreated graphene-supported expanded graphite, nano silica aerogel, ammonium polyphosphate, pentaerythritol, melamine, ethylene-vinyl acetate copolymer, maleic anhydride grafted polyethylene, nano montmorillonite, silicon carbide whiskers, amino-terminated polyether, antioxidant 1010, and hindered amine light stabilizer 770, heat to 40-50℃, and continue stirring at 300-500 r / min for 20-30 minutes to obtain a uniform and viscous core layer slurry; S2. Surface layer preparation: Add cement-based cementitious materials, fly ash, and titanium dioxide to a mixing tank in proportion, and dry mix at a rate of 1000-1500 r / min for 5-10 minutes to ensure uniform mixing of dry materials; add deionized water and continue mixing at 1000-1500 r / min for 10-15 minutes to form a cement paste; add hydroxypropyl methylcellulose ether, polyacrylonitrile fiber, pearl cotton short fiber, waterborne epoxy resin emulsion, silane-modified polyurethane emulsion, and defoamer, pre-mix at 1500 r / min for 5-8 minutes, and then high-speed shear at 2000-3000 r / min for 15-25 minutes to obtain a uniform and fine surface layer slurry; S3. Composite Molding: Prepare a cuboid mold, apply a release agent to the inner wall of the mold, and first evenly coat the bottom of the mold with a 1-3mm thick surface layer slurry, smoothing it with a scraper; after the bottom surface layer slurry has initially solidified, lay the core layer slurry into the mold, controlling the thickness to 30-60mm. During the laying process, gently vibrate with a vibrator to remove air bubbles inside the core layer; after the core layer is laid, evenly coat the surface of the core layer with a 1-3mm thick surface layer slurry, and smooth it again with a scraper; send the mold into the press, using a step-by-step pressurization method, first holding the pressure at 0.5MPa for 5 minutes, then increasing the pressure to 1.0-1.5MPa and holding it for 5-15 minutes; S4. Curing and Solidification: Remove the pressurized mold and place it in a room temperature curing chamber for 24-48 hours. The curing environment temperature is 20-25℃ and the humidity is 60-70%. After room temperature curing, remove the insulation board blank from the mold and send it to a steam curing kiln for steam curing. The curing temperature is 60-80℃ and the humidity is ≥90%. The curing time is 12-24 hours, and the heating rate is controlled at 5-10℃ / h. After steam curing, cool it down to room temperature at a cooling rate of 3-5℃ / h. Finally, microwave dry the insulation board with a microwave power of 500-800W for 20-30 minutes to make the moisture content of the insulation board ≤8%, thus obtaining the finished insulation board.

4. The preparation method according to claim 3, characterized in that, The heating and stirring process in S1 is carried out in two stages. In the first stage, the temperature is raised to 40°C and stirred for 10 minutes to ensure that the amino-terminated polyether and maleic anhydride-grafted polyethylene are in full contact. In the second stage, the temperature is raised to 45-50°C and stirred for another 10-20 minutes to ensure that the degree of esterification reaction reaches more than 70%. The crosslinking uniformity is improved by controlling the temperature in stages. The pretreatment steps of graphene-supported expanded graphite in S1 are as follows: graphene-supported expanded graphite is added to an ethanol solution, silane coupling agent KH560 is added, the temperature is raised to 60°C and stirred for 2 hours, filtered, and then dried at 80°C for 4 hours to complete the modification.

5. The preparation method according to claim 3, characterized in that, In S3, the vibrator frequency is 20-30Hz and the vibration time is 3-5 minutes. During the vibration process, the vibrator probe should not penetrate more than 10mm into the core layer slurry to avoid damaging the bottom surface structure. In S4, microwave drying is carried out intermittently, with a 5-minute stop every 10 minutes of drying. After drying, the insulation board needs to be inspected for dimensions.

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