Reinforced aerogel modified polyurethane foaming insulation board and preparation method thereof

Abstract

The invention discloses a reinforced aerogel modified polyurethane foaming insulation board and a preparation method thereof, and belongs to the technical field of polyurethane insulation flame-retardant materials. The reinforced aerogel modified polyurethane foaming insulation board is prepared by foaming, curing and molding a component A and a component B, the component A comprises the following raw material components in parts by weight: 100 parts of polyol, 6-15 parts of modified silicon dioxide aerogel, 8-18 parts of modified glass fibers, 20-35 parts of a hybrid ceramic composite flame retardant, 4-8 parts of a foaming agent, 0.5-1.5 parts of water, 1.0-2.0 parts of a silicone oil foam stabilizer and 0.5-1.5 parts of a composite catalyst; the component B is polyphenyl polymethylene polyisocyanate, and the mass ratio of the component B to the component A is (0.8-1.0): 1. By adopting the modified silicon dioxide aerogel, the modified glass fiber and the hybrid ceramic composite flame retardant and matching with the proportion of the component A and the component B, the heat conductivity coefficient is remarkably reduced, the excellent heat preservation performance is reserved, the mechanical strength of the board is enhanced, a ceramic barrier can be formed at high temperature, and synergistic improvement of ultralow heat conductivity, high strength and toughness and high-grade flame retardant performance is achieved.

Description

Technical Field

[0001] This application relates to a reinforced aerogel-modified polyurethane foam insulation board and its preparation method, belonging to the technical field of polyurethane insulation and flame retardant materials. Background Technology

[0002] Rigid polyurethane (PU) foam materials play an irreplaceable role in building energy conservation, cold chain logistics, and special equipment insulation due to their extremely low thermal conductivity, excellent closed-cell structure, and good construction performance. With increasingly stringent building fire protection codes, developing polyurethane insulation boards that combine ultra-low thermal conductivity with high-grade flame retardancy (Class A or near-Class A) has become a core direction for industry development. Currently, existing technologies attempt to construct a high-performance composite system by introducing aerogel fillers with nanoporous structures into the foaming system to effectively suppress gas convection within the cells, while fiber materials compensate for matrix embrittlement caused by the large addition of fillers.

[0003] However, in existing modification practices, the thermal insulation performance of aerogels is often difficult to fully realize in polyurethane systems. The core reason for this is the interference of the capillary effect. Most existing silica aerogel surface treatments rely on silane coupling agents or simple surface hydrophobication methods. This two-dimensional modification makes it difficult to construct an effective physical barrier at the nanoscale pore openings of the aerogel. In the early stages of the polyurethane foaming reaction, the system viscosity is low, and isocyanates or polyol monomers with extremely strong penetrating power inevitably seep into the aerogel particles through capillary action, occupying the nanopores originally intended to block heat during the subsequent curing process. This pore-filling phenomenon not only directly leads to a significant rebound in the thermal conductivity of the composite material, negating the initial purpose of introducing aerogel to reduce thermal conductivity, but also results in a serious waste of expensive raw materials, becoming a "fatal flaw" restricting the large-scale application of aerogels in the field of thermal insulation.

[0004] On the other hand, while traditional reinforcement and flame-retardant modification methods improve performance, they also significantly weaken the mechanical properties of the boards and pose safety hazards. Current technologies often limit the treatment of reinforcing filler glass fibers to chemical grafting or plasma etching, lacking deep three-dimensional modification of the fiber surface morphology. This results in insufficient mechanical anchoring between the fiber and the polyurethane foam cell walls, making them prone to interfacial debonding during impact or compression tests. More seriously, many commercially available so-called high-performance flame-retardant polyurethane boards rely heavily on adding large amounts of traditional powdered flame retardants such as ammonium polyphosphate, aluminum hydroxide, or melamine. The expanded char layer formed by these flame retardants when exposed to high-temperature flame sources is extremely loose and has low physical strength. It is easily broken and detached under the intense impact of the flame jet, causing a "fire penetration" phenomenon and a precipitous drop in the mechanical strength of the board.

[0005] In summary, existing polyurethane insulation board modification technologies exhibit significant synergistic failure characteristics when facing multiple demands for extreme insulation, high strength and toughness, and extreme fire safety performance. How to meet the multiple requirements of polyurethane insulation boards for insulation performance, mechanical properties, and flame retardancy, and achieve a balance among these properties to comprehensively improve the material's performance, is a key scientific challenge that urgently needs to be solved in the field of polyurethane insulation materials. Summary of the Invention

[0006] To address the aforementioned issues, this application provides an enhanced aerogel-modified polyurethane foam insulation board and its preparation method. This application utilizes modified silica aerogel, modified glass fiber, and a hybrid ceramicized composite flame retardant, along with the appropriate ratio of components A and B. This effectively prevents isocyanate and polyol from clogging the aerogel pores, significantly reducing the thermal conductivity while retaining excellent insulation performance. Simultaneously, it enhances the interfacial bonding between the fiber and polyurethane, strengthens the board's mechanical strength, and allows the formation of a dense ceramicized barrier at high temperatures, achieving a synergistic improvement in ultra-low thermal conductivity, high strength and toughness, and high-grade flame retardant performance.

[0007] According to one aspect of this application, a reinforced aerogel-modified polyurethane foam insulation board is provided, which is obtained by foaming and curing component A and component B. Component A, by weight, comprises the following raw material components: 100 parts polyol, 6-15 parts modified silica aerogel, 8-18 parts modified glass fiber, 20-35 parts hybrid ceramic composite flame retardant, 4-8 parts foaming agent, 0.5-1.5 parts water, 1.0-2.0 parts silicone oil foam stabilizer, and 0.5-1.5 parts composite catalyst; component B is polyphenyl polymethylene polyisocyanate, and the mass ratio of component B to component A is (0.8-1.0):1.

[0008] Specifically, this application specifies the composition and ratio of components A and B. The modified silica aerogel, modified glass fiber, and hybrid ceramic composite flame retardant work synergistically to retain good thermal insulation and mechanical properties while forming a dense ceramic barrier at high temperatures, giving the board the ability to resist burn-through by open flame.

[0009] Specifically, polyols provide the polyurethane skeleton; the mass ratio of component B to component A is (0.8~1.0):1, and the polyphenyl polymethylene polyisocyanate of component B forms a heat-resistant isocyanurate ring under excess index; modified silica aerogel serves as the core heat-insulating filler, which can block heat convection; modified glass fiber serves as the core three-dimensional reinforcing skeleton, which can bear macroscopic stress and buffer curing shrinkage; hybrid ceramic composite flame retardant completely replaces traditional inorganic flame retardant powder, serving as the core anti-burn-through medium; water and foaming agent synergistically generate closed-cell gas, stabilizer ensures fine pores, and composite catalyst ensures that foaming and cross-linking curing occur simultaneously.

[0010] Optionally, the polyol is a polyether polyol and a polyester polyol; and / or The hybrid ceramicized composite flame retardant comprises liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene, wherein the mass ratio of the liquid polyborosilazane to hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene is (2~4):1.

[0011] Specifically, liquid polyborosilicate acts as a reactive plasticizer at room temperature without increasing the system viscosity. At temperatures above 500℃, the polyborosilicate undergoes crosslinking and pyrolysis, transforming in situ into a dense and hard Si-BCN refractory ceramic layer. The high char-forming properties of hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene provide the initial carbon-rich framework for the ceramicization of polyborosilicate; the specific ratio of liquid polyborosilicate and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene ensures a two-layer armor transition of "charring at the bottom layer and ceramic forming at the surface layer" during ignition, avoiding the defects of an overly brittle pure ceramic layer or a easily damaged pure carbon layer.

[0012] Optionally, the modified silica aerogel is a cage-type polysilsesquioxane shielded modified silica aerogel; the modified glass fiber is a ZnO nanowire-flexible polyether modified glass fiber.

[0013] Optionally, the cage-shaped polysilsesquioxane-modified silica aerogel is prepared by the following steps: Hydrophobic silica aerogel was dispersed in anhydrous ethanol, and octa(γ-isocyanopropyl) cage-type silsesquioxane and dibutyltin dilaurate catalyst were added. Under nitrogen protection, the mixture was refluxed at 60-75℃ for 4-6 h, centrifuged, washed, and vacuum dried to obtain cage-type polysilsesquioxane shielded modified silica aerogel.

[0014] Optionally, the amount of the octa(γ-isocyanopropyl) cage-like silsesquioxane added is 10-20% of the mass of the hydrophobic silica aerogel.

[0015] Specifically, the prepared cage-type polysilsesquioxane shielded modified silica aerogel has a rigid octa(γ-isocyanate-propyl) cage-type silsesquioxane cage structure grafted on its surface, and retains residual isocyanate groups.

[0016] Specifically, octa(γ-isocyanate-propyl) cage-like silsesquioxane is a nano-macromolecule with a three-dimensional rigid cage structure and a diameter of about 1.5 nm. When it is grafted onto the surface of silica aerogel, a large number of rigid octa(γ-isocyanate-propyl) cage-like silsesquioxane cages form a physical nano-shield with extremely large steric hindrance at the opening of the aerogel mesopores. This shielding layer effectively blocks the capillary channels and prevents low-viscosity polyurethane from penetrating into the interior of the aerogel during foaming, thereby locking in the ultra-low thermal conductivity of the aerogel. At the same time, the residual isocyanate groups on the periphery of the octa(γ-isocyanate-propyl) cage-like silsesquioxane can form covalent chemical crosslinks with the polyurethane matrix, avoiding debonding at the filler interface.

[0017] Optionally, the ZnO nanowires-flexible polyether-modified glass fibers are prepared by the following steps: Alkali-free chopped glass fibers were immersed in a hydrochloric acid-dopamine solution and stirred at room temperature for 24-36 hours to obtain glass fibers with a polydopamine coating. Then, the glass fibers with the polydopamine coating were immersed in an aqueous solution containing zinc acetate and hexamethylenetetramine and hydrothermally reacted in a water bath at 85-95°C for 6-8 hours. After washing and drying, they were immersed in a solution of isocyanate-terminated polyether prepolymer and reacted at 65-75°C for 2.5-3.5 hours to obtain ZnO nanowire-flexible polyether modified glass fibers.

[0018] Optionally, the concentration of the dopamine hydrochloride solution is 1.5~3 g / L, and the solvent of the dopamine hydrochloride solution is a Tris-HCl buffer solution with pH=8.5~10.

[0019] Specifically, this application first coats glass fibers with a polydopamine coating, then grows a ZnO nanowire array in situ on the surface of the glass fibers through a hydrothermal reaction, and then grafts polyether segments onto the residual hydroxyl / amino groups on the surface of ZnO and the polydopamine coating to obtain modified glass fibers.

[0020] Specifically, the ZnO nanowire array constructed on the surface of glass fiber in this application breaks the smooth two-dimensional surface of conventional glass fiber, forming a multi-level rough structure similar to nanobarbs, which greatly enhances the mechanical interlocking force between glass fiber and polyurethane foam cell wall; the further grafted flexible polyether segments introduce stress buffer springs between rigid glass fiber and rigid resin matrix, effectively dissipating external impact loads and significantly improving the compressive and bending toughness of the board.

[0021] The polyol is composed of flame-retardant aromatic polyether polyol and aromatic polyester polyol in a mass ratio of 7:3 to 8:2; the foaming agent is obtained by compounding cyclopentane and 1-chloro-3,3,3-trifluoropropylene in a mass ratio of 1:1 to 1:2; the silicone oil foam stabilizer is a polyether-modified polysiloxane foam stabilizer; the composite catalyst is composed of N,N-dimethylcyclohexylamine and 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine in a mass ratio of 1:1.5 to 1:2.5.

[0022] Specifically, the flame-retardant aromatic polyether polyol has a hydroxyl value of 350~450 mgKOH / g; the aromatic polyester polyol has a hydroxyl value of 200~300 mgKOH / g.

[0023] Specifically, flame-retardant aromatic polyether polyols with high hydroxyl values ​​and high functionality can provide extremely high crosslinking density, giving the polyurethane matrix excellent initial rigidity and dimensional stability to resist cell deformation after the addition of aerogel and glass fiber; while the introduction of aromatic polyester polyols with moderate hydroxyl values ​​can not only increase the benzene ring density in the system to greatly improve compatibility with the hybrid ceramic flame-retardant system, but also rapidly crosslink to form a tough carbon-rich skeleton in the early stage of combustion, providing a solid underlying support for the subsequent ceramic reaction; the two achieve the best balance between mechanical toughness and flame-retardant charring properties under specific ratios.

[0024] Specifically, the foaming agent is a mixture of cyclopentane and 1-chloro-3,3,3-trifluoropropylene (HCFO-1233zd) in a mass ratio of 1:1 to 1:2. Cyclopentane has excellent solubility in polyether polyols, ensuring uniform nucleation and excellent closed-cell ratio in the initial foaming stage. HCFO-1233zd, as a fourth-generation environmentally friendly fluoroolefin foaming agent, not only has an extremely low gaseous thermal conductivity, further reducing the overall thermal conductivity of the board, but more importantly, it is itself a non-flammable gas. When it fills the polyurethane foam cells, it can release flame-retardant gas upon contact with an open flame to dilute the oxygen concentration, achieving flame retardancy in the gas phase.

[0025] Specifically, the silicone oil foam stabilizer is a polyether-modified polysiloxane-based rigid polyurethane foam stabilizer. The polyether segments in the polyether-modified polysiloxane have good compatibility with the polyurethane polyol matrix, while the polysiloxane segments are specifically enriched at the gas-liquid interface of the foaming system, significantly reducing the surface tension of the system. In the high-filler (aerogel and glass fiber) system of this invention, it can form a highly elastic bubble film, effectively preventing bubble coalescence and collapse caused by the "piercing" effect of solid particles, thereby ensuring high closed-cell rate and excellent thermal insulation performance.

[0026] Specifically, the composite catalyst is composed of N,N-dimethylcyclohexylamine (PC-8) and 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine (PC-41) in a mass ratio of 1:1.5 to 1:2.5. In the high isocyanate index system established in this invention, the balance between foaming, gelation, and trimerization is crucial. N,N-dimethylcyclohexylamine (PC-8), as a highly efficient foaming catalyst, preferentially catalyzes the reaction of water with PMDI to release carbon dioxide, providing initial expansion momentum for the high-viscosity system. 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine (PC-41), as a potent trimerization catalyst, not only accelerates the gel crosslinking of polyols in the later stages of foaming, but more importantly, it promotes the trimerization of excess isocyanate groups, generating a large amount of highly thermally stable isocyanurate (PIR) six-membered ring skeletons. This specific ratio of foaming-trimer composite catalytic network perfectly matches the molding rhythm of the hybrid ceramic flame-retardant system, preventing bubble collapse caused by high-filling systems and significantly improving the intrinsic flame-retardant and temperature-resistant upper limit of the insulation board at the resin molecular level.

[0027] According to another aspect of this application, a method for preparing the above-mentioned reinforced aerogel-modified polyurethane foam insulation board is also provided, comprising the following steps: (1) Pre-dispersion: Take the raw materials in the indicated weight proportions, add the hybrid ceramic composite flame retardant and the modified silica aerogel to the polyol in sequence, disperse evenly, and obtain a dispersion; (2) Constructing a three-dimensional framework: Add modified glass fiber to the dispersion, stir and mix to obtain component A premix; (3) Curing and foaming: Add water, foaming agent, stabilizer and composite catalyst to component A premix in sequence, stir evenly, add component B, mix at high speed and quickly pour into mold; (4) Curing and maturation: Curing and molding at a constant temperature of 45~60℃ for 22~28h, demolding and cutting to obtain reinforced aerogel modified polyurethane foam insulation board.

[0028] Optionally, in step (1), the dispersion is carried out by a high-shear emulsifier with a speed of 3000~5000 r / min and a time of 15~20 min; in step (2), the mixing is carried out by a planetary mixer with a mixing speed of 50~100 r / min and a mixing time of 25~35 min; in step (3), the high-speed mixing speed is 1500~2000 r / min and the time is 6~10 s.

[0029] Specifically, this application first performs high-speed dispersion to form a stable nano-dispersion; then it is stirred at low speed to avoid fiber breakage. This step-by-step preparation process enables the residual isocyanate groups on the aerogel surface, the flexible polyether chains on the glass fiber surface, and the flame retardant system to undergo uniform and thorough chemical covalent bonding with component B.

[0030] The beneficial effects of this application include, but are not limited to: 1. According to this application, a reinforced aerogel-modified polyurethane foam insulation board utilizes the synergistic effect of cage-type polysilsesquioxane-shielded modified silica aerogel, ZnO nanowire-flexible polyether-modified glass fiber, and hybrid ceramicized composite flame retardant. Microscopically, it blocks the penetration of polyurethane monomers into the aerogel pores to preserve its thermal resistance performance; mesoscopically, it constructs a multi-scale reinforcing skeleton to strengthen interfacial bonding; and macroscopically, it utilizes a ceramicization reaction to transform the flammable organic matrix into a high-temperature resistant inorganic barrier upon exposure to fire, thus achieving a comprehensive improvement in thermal insulation performance, mechanical properties, and flame retardant performance.

[0031] 2. According to this application, a reinforced aerogel-modified polyurethane foam insulation board is made by modifying silica aerogel with octa(γ-isocyanate-propyl) cage-like silsesquioxane. The three-dimensional rigid cage-like structure of the octa(γ-isocyanate-propyl) cage-like silsesquioxane molecule is used to construct a physical bottleneck shielding layer at the pore opening of the aerogel, which completely blocks the penetration of polyurethane monomers and perfectly preserves the nanoscale multiple thermal scattering effect inside the aerogel. This breaks through the limitation of traditional silane coupling agents that can only change the surface energy of aerogel, and reduces the thermal conductivity of the board to an extremely low 0.0158~0.0185 W / (m·K).

[0032] 3. According to this application, a reinforced aerogel-modified polyurethane foam insulation board is made of ZnO nanowires-flexible polyether-modified glass fiber. On the one hand, it significantly improves the mechanical interlocking force and stress dissipation capacity of the matrix, completely solving the problem of polyurethane embrittlement and powdering caused by high filling, and greatly improving the compressive strength. On the other hand, the ZnO nanowires on the surface of the ZnO nanowires-flexible polyether-modified glass fiber act as a highly efficient multiphase catalyst and heterogeneous nucleation site for the ceramicization reaction of liquid polyborosilicate, guiding the flame retardant to preferentially ceramicize on the fiber surface, and finally forming a non-shrinkage and non-cracking composite fire-resistant armor with glass fiber as the steel reinforcement, aerogel silica network as the aggregate, and Si-BCN ceramic layer as the matrix, so that the board has a flame-proof burn-through capability of more than 2 hours.

[0033] 4. According to the preparation method of the aerogel-modified polyurethane foam insulation board of this application, a step-type preparation process of high-shear nano-dispersion and low-speed fiber skeleton construction is adopted. This step-type preparation process enables the residual isocyanate groups on the surface of aerogel, the flexible polyether chains on the surface of glass fiber, and the flame retardant system to undergo uniform and thorough chemical covalent bonding with component B. The whole system presents a chemical cross-linking and interpenetrating state, ensuring that the product does not undergo component migration and performance degradation during long-term use under harsh conditions such as extreme cold and high humidity. Detailed Implementation

[0034] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of skill in the art. All reagents and raw materials used in this invention are readily available through conventional means. Unless otherwise specified, all reagents and raw materials used in this invention are used in accordance with conventional methods in the art or according to the product instructions. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention. The preferred embodiments and materials described in this patent are for illustrative purposes only. In the following examples and comparative examples, the length of the alkali-free chopped glass fibers is 3-6 mm and the diameter is 11 μm; the solvent for the dopamine hydrochloride solution is a Tris-HCl buffer solution with pH=8.5; the particle size of the hydrophobic silica aerogel powder is 20-80 μm, the porosity is 92%, and the thermal conductivity is 0.018 W / (m²). K), water contact angle 135°.

[0036] Example 1 Preparation of cage-type polysilsesquioxane-modified silica aerogel: 100g of hydrophobic silica aerogel was dispersed in 1L of anhydrous ethanol, and 15g of octa(γ-isocyanopropyl) cage-like silsesquioxane and 0.1g of dibutyltin dilaurate catalyst were added. The mixture was refluxed at 65℃ for 5h under nitrogen protection, centrifuged, washed, and vacuum dried to obtain cage-like polysilsesquioxane-shielded modified silica aerogel.

[0037] Preparation of ZnO nanowires-flexible polyether-modified glass fibers: 100g of alkali-free chopped glass fibers with a length of 3-6mm were immersed in a 2g / L dopamine hydrochloride solution and stirred at room temperature for 24h to obtain glass fibers with a polydopamine coating. Then, the glass fibers with the polydopamine coating were immersed in an aqueous solution containing 0.05mol / L zinc acetate and 0.05mol / L hexamethylenetetramine and hydrothermally reacted in a 90℃ water bath for 6h. After washing and drying, they were immersed in a 10wt% isocyanate-terminated polyether prepolymer solution and reacted at 70℃ for 3h to obtain ZnO nanowire-flexible polyether modified glass fibers.

[0038] Hybrid ceramic flame retardant formulation: Liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene were mixed at a mass ratio of 3:1 and ultrasonically dispersed until uniform.

[0039] A method for preparing reinforced aerogel-modified polyurethane foam insulation board: (1) Pre-dispersion: Take the raw materials in each weight proportion, add 30 parts of hybrid ceramic composite flame retardant and 10 parts of modified silica aerogel to 100 parts of polyol (70 parts of flame retardant aromatic polyether polyol (hydroxyl value 450 mgKOH / g) and 30 parts of aromatic polyester polyol (hydroxyl value 300 mgKOH / g) in sequence, disperse using a high shear emulsifier at a speed of 4000 r / min for 15 min, disperse evenly to obtain a dispersion; (2) Construction of three-dimensional skeleton: 12 parts of modified glass fiber were added to the dispersion, and a planetary mixer was used to mix the mixture at a speed of 80 r / min for 30 min to obtain component A premix. (3) Curing and foaming: Add 1.0 part of water, 6 parts of composite foaming agent (cyclopentane and HCFO-1233zd mass ratio 1:1), 1.5 parts of silicone oil foam stabilizer (polyether modified polysiloxane foam stabilizer (TegostabB8462)) and 1.0 part of composite catalyst with PC-8 / PC-41 mass ratio of 1:2 to component A premix in sequence, stir evenly, add 140 parts of component B PMDI, mix at high speed, speed of 2000 r / min, time of 8s, and quickly pour into the mold; (4) Curing and maturation: Curing and molding at a constant temperature of 50℃ for 24 hours, demolding and cutting to obtain reinforced aerogel modified polyurethane foam insulation board.

[0040] Example 2 Preparation of cage-type polysilsesquioxane-modified silica aerogel: 100g of hydrophobic silica aerogel was dispersed in 1L of anhydrous ethanol, and 15g of octa(γ-isocyanopropyl) cage-like silsesquioxane and 0.1g of dibutyltin dilaurate catalyst were added. Under nitrogen protection, the mixture was refluxed at 60℃ for 6h, centrifuged, washed, and vacuum dried to obtain cage-like polysilsesquioxane-shielded modified silica aerogel.

[0041] Preparation of ZnO nanowires-flexible polyether-modified glass fibers: 100g of alkali-free chopped glass fibers with a length of 3-6mm were immersed in a 1.5g / L dopamine hydrochloride solution and stirred at room temperature for 30h to obtain glass fibers with a polydopamine coating. Then, the glass fibers with the polydopamine coating were immersed in an aqueous solution containing 0.05mol / L zinc acetate and 0.05mol / L hexamethylenetetramine and hydrothermally reacted in a water bath at 85℃ for 8h. After washing and drying, they were immersed in a 10wt% isocyanate-terminated polyether prepolymer solution and reacted at 65℃ for 3.5h to obtain ZnO nanowire-flexible polyether modified glass fibers.

[0042] Hybrid ceramic flame retardant formulation: Liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene were mixed at a mass ratio of 3:1 and ultrasonically dispersed until uniform.

[0043] A method for preparing reinforced aerogel-modified polyurethane foam insulation board: (1) Pre-dispersion: Take the raw materials in each weight proportion, add 20 parts of hybrid ceramic composite flame retardant and 6 parts of modified silica aerogel to 100 parts of polyol (80 parts of flame retardant aromatic polyether polyol (hydroxyl value 350 mgKOH / g) and 20 parts of aromatic polyester polyol (hydroxyl value 200 mgKOH / g) in sequence, disperse using a high shear emulsifier at a speed of 3000 r / min for 20 min, disperse evenly to obtain a dispersion; (2) Constructing a three-dimensional framework: Add 8 parts of modified glass fiber to the dispersion, use a planetary mixer, stir at a speed of 100 r / min for 25 min, stir and mix to obtain component A premix; (3) Curing and foaming: Add 0.5 parts of water, 4 parts of composite foaming agent (cyclopentane and HCFO-1233zd mass ratio 1:1.5), 1.0 part of silicone oil foam stabilizer (polyether modified polysiloxane foam stabilizer (TegostabB8462)) and 0.5 parts of composite catalyst with PC-8 / PC-41 mass ratio of 1:1.5 to component A premix in sequence, stir evenly, add 140 parts of PMDI of component B, mix at high speed, speed of 1500 r / min, time of 10s, and quickly inject into the mold; (4) Curing and maturation: Curing and molding at a constant temperature of 60℃ for 22 hours, demolding and cutting to obtain reinforced aerogel modified polyurethane foam insulation board.

[0044] Example 3 Preparation of cage-type polysilsesquioxane-modified silica aerogel: 100g of hydrophobic silica aerogel was dispersed in 1L of anhydrous ethanol, and 15g of octa(γ-isocyanopropyl) cage-like silsesquioxane and 0.1g of dibutyltin dilaurate catalyst were added. The mixture was refluxed at 75℃ for 4h under nitrogen protection, centrifuged, washed, and vacuum dried to obtain cage-like polysilsesquioxane-shielded modified silica aerogel.

[0045] Preparation of ZnO nanowires-flexible polyether-modified glass fibers: 100g of alkali-free chopped glass fibers with a length of 3-6mm were immersed in a 3g / L dopamine hydrochloride solution and stirred at room temperature for 36h to obtain glass fibers with a polydopamine coating. Then, the glass fibers with the polydopamine coating were immersed in an aqueous solution containing 0.05mol / L zinc acetate and 0.05mol / L hexamethylenetetramine and hydrothermally reacted in a 95℃ water bath for 6h. After washing and drying, they were immersed in a 10wt% isocyanate-terminated polyether prepolymer solution and reacted at 75℃ for 2.5h to obtain ZnO nanowire-flexible polyether modified glass fibers.

[0046] Hybrid ceramic flame retardant formulation: Liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene were mixed at a mass ratio of 3:1 and ultrasonically dispersed until uniform.

[0047] A method for preparing reinforced aerogel-modified polyurethane foam insulation board: (1) Pre-dispersion: Take the raw materials in each weight proportion, add 35 parts of hybrid ceramic composite flame retardant and 15 parts of modified silica aerogel to 100 parts of polyol (70 parts of flame retardant aromatic polyether polyol (hydroxyl value 450 mgKOH / g) and 30 parts of aromatic polyester polyol (hydroxyl value 300 mgKOH / g) in sequence, disperse using a high shear emulsifier at a speed of 5000 r / min for 15 min, disperse evenly to obtain a dispersion; (2) Constructing a three-dimensional framework: Add 18 parts of modified glass fiber to the dispersion, use a planetary mixer, stir at a speed of 50 r / min for 35 min, stir and mix to obtain component A premix; (3) Curing and foaming: Add 1.5 parts of water, 8 parts of composite foaming agent (cyclopentane and HCFO-1233zd mass ratio 1:2), 2.0 parts of silicone oil foam stabilizer (polyether modified polysiloxane foam stabilizer (TegostabB8462)) and 1.5 parts of composite catalyst with PC-8 / PC-41 mass ratio of 1:2.5 to component A premix in sequence, stir evenly, add 140 parts of component B PMDI, mix at high speed at 2000 r / min for 6 s and quickly inject into the mold; (4) Curing and maturation: Curing and molding at a constant temperature of 45℃ for 28 hours, demolding and cutting to obtain reinforced aerogel modified polyurethane foam insulation board.

[0048] Example 4 The difference between Example 4 and Example 1 is that in the preparation of cage-type polysilsesquioxane shielded modified silica aerogel, the amount of octa(γ-isocyanate-propyl)cage-type silsesquioxane added is 10g; in the preparation of hybrid ceramic flame retardant, liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene are mixed at a mass ratio of 2:1, the total amount of hybrid ceramic flame retardant remains unchanged, and the ultrasonic dispersion is uniform, and the rest are the same.

[0049] Example 5 The difference between Example 5 and Example 1 is that 12 parts of modified silica aerogel, 15 parts of modified glass fiber, and 8 parts of foaming agent are used, while the rest are the same.

[0050] Example 6 The difference between Example 6 and Example 1 lies in the formulation of the hybrid ceramic flame retardant: Liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene were mixed at a mass ratio of 4:1 and ultrasonically dispersed evenly. The amount of hybrid ceramic flame retardant added was 28 parts, and the rest were the same.

[0051] Example 7 The difference between Example 7 and Example 1 lies in the formulation of the hybrid ceramic flame retardant: Liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene were mixed at a mass ratio of 1:1 and ultrasonically dispersed until uniform, with the rest being the same.

[0052] Example 8 The difference between Example 8 and Example 1 is that in the preparation of cage-type polysilsesquioxane shielded modified silica aerogel, the amount of octa(γ-isocyanate propyl) cage-type silsesquioxane added is 5% of the mass of the hydrophobic silica aerogel.

[0053] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the silica aerogel was modified with KH-550 as a silane coupling agent; the glass fiber was modified by soaking and ultrasonic treatment with KH-550; and the hybrid ceramic flame retardant was replaced with a flame retardant obtained by mixing ammonium polyphosphate and melamine in a mass ratio of 3:1. All other aspects are the same.

[0054] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the hybrid ceramic flame retardant is replaced with a flame retardant obtained by mixing ammonium polyphosphate and melamine in a mass ratio of 3:1, and all other aspects are the same.

[0055] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the silica aerogel was not modified, but otherwise they are the same.

[0056] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the glass fiber was not modified, but otherwise they are the same.

[0057] Experimental Example 1 After the insulation boards prepared in Examples 1-8 and Comparative Examples 1-4 were placed for 7 days, performance tests were conducted according to the core technical indicators. The applicable standards were: thermal conductivity - GB / T10294; combustion performance - GB8624-2012; compressive strength - GB / T8813; volumetric water absorption rate - GB / T8810; apparent density - GB / T6343. The test results are shown in Table 1. Table 1 Performance Test Results

[0058] As shown in Table 1, the thermal conductivity of Examples 1-6 remained at an extremely low level (0.0158~0.0185 W / (m·K)), significantly better than Comparative Examples 1 and 3. This demonstrates that the rigid cage-like spatial shielding of octa(γ-isocyanate-propyl)cage-type silsesquioxane successfully prevented polyurethane from entering the micropores of the aerogel, thus maintaining the thermal insulation properties of the aerogel better than traditional silanes, such as Comparative Example 1. In Example 8, during the preparation of cage-type polysilsesquioxane-modified silica aerogel, the amount of octa(γ-isocyanate-propyl) cage-type silsesquioxane added was 5% of the mass of the hydrophobic silica aerogel. The thermal conductivity of the insulation board prepared from it was significantly increased compared to Examples 1-6, while the compressive strength was significantly decreased. This indicates that the content of octa(γ-isocyanate-propyl) cage-type silsesquioxane was too low to completely prevent polyurethane from entering the micropores of the aerogel, and there was not enough residual isocyanate groups on the periphery of the aerogel particles to form covalent chemical crosslinks with the polyurethane matrix, resulting in a decrease in the compressive strength of the insulation board.

[0059] The compressive strength of Examples 1-6 ranges from 280 to 335 kPa, which is attributed to the barbed mechanical interlocking effect of the ZnO nanowire-flexible polyether structure, which completely changes the weakness of conventional glass fiber in Comparative Example 1, which is prone to debonding.

[0060] In a high-temperature blowtorch test at 1000℃, Examples 1-6 and Example 8 all remained unburned for over 2 hours and formed a dense ceramic layer, achieving the A2 flame retardant standard. Compared to Comparative Example 2, it is evident that only when the hybrid ceramic flame retardant coexists with modified glass fiber and modified silica aerogel can a heterogeneous nucleation synergistic effect be activated, forming an extremely robust micro-nano composite defense. Example 7 changed the mass ratio of liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene to 1:1, thus failing to form a dense ceramic layer. Its combustion performance only reached B1 level, and it burned through before reaching 2 hours. Therefore, only when the mass ratio of liquid polyborosilazane to hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene is (2-4):1 does it exhibit excellent flame retardant performance and ceramicization. Comparative Example 4: The glass fiber was not modified, so there was no ZnO nanowire to act as an efficient heterogeneous catalyst and nucleation site for the ceramicization reaction of liquid polyborosilazane. Therefore, the resulting ceramic layer had low hardness, and the carbon layer existed but was not dense.

[0061] This demonstrates that the various component adjustments of the present invention can all exert a highly significant synergistic innovation effect within the scope of the claims, possessing extremely high practical application value and technical advantages that surpass existing patents.

[0062] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A reinforced aerogel-modified polyurethane foam insulation board, characterized in that, The product is prepared by foaming and curing components A and B. By weight, component A comprises the following raw materials: 100 parts polyol, 6-15 parts modified silica aerogel, 8-18 parts modified glass fiber, 20-35 parts hybrid ceramic composite flame retardant, 4-8 parts foaming agent, 0.5-1.5 parts water, 1.0-2.0 parts silicone oil foam stabilizer, and 0.5-1.5 parts composite catalyst. Component B is polyphenyl polymethylene polyisocyanate, and the mass ratio of component B to component A is (0.8-1.0):

1.

2. The reinforced aerogel-modified polyurethane foam insulation board according to claim 1, characterized in that, The polyol is a polyether polyol and a polyester polyol; and / or The hybrid ceramicized composite flame retardant comprises liquid polyborosilazane and hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene, wherein the mass ratio of the liquid polyborosilazane to hexa-(4-hydroxymethylphenoxy)cyclotriphosphazene is (2~4):

1.

3. The reinforced aerogel-modified polyurethane foam insulation board according to claim 1, characterized in that, The modified silica aerogel is a cage-type polysilsesquioxane shielded modified silica aerogel; the modified glass fiber is a ZnO nanowire-flexible polyether modified glass fiber.

4. The reinforced aerogel-modified polyurethane foam insulation board according to claim 3, characterized in that, The cage-shaped polysilsesquioxane-modified silica aerogel was prepared by the following steps: Hydrophobic silica aerogel was dispersed in anhydrous ethanol, and octa(γ-isocyanopropyl) cage-type silsesquioxane and dibutyltin dilaurate catalyst were added. Under nitrogen protection, the mixture was refluxed at 60-75℃ for 4-6 h, centrifuged, washed, and vacuum dried to obtain cage-type polysilsesquioxane shielded modified silica aerogel.

5. The reinforced aerogel-modified polyurethane foam insulation board according to claim 4, characterized in that, The amount of the octa(γ-isocyanopropyl) cage-like silsesquioxane added is 10-20% of the mass of the hydrophobic silica aerogel.

6. The reinforced aerogel-modified polyurethane foam insulation board according to claim 3, characterized in that, The ZnO nanowires-flexible polyether-modified glass fibers are prepared by the following steps: Alkali-free chopped glass fibers were immersed in a hydrochloric acid-dopamine solution and stirred at room temperature for 24-36 hours to obtain glass fibers with a polydopamine coating. Then, the glass fibers with the polydopamine coating were immersed in an aqueous solution containing zinc acetate and hexamethylenetetramine and hydrothermally reacted in a water bath at 85-95°C for 6-8 hours. After washing and drying, they were immersed in a solution of isocyanate-terminated polyether prepolymer and reacted at 65-75°C for 2.5-3.5 hours to obtain ZnO nanowire-flexible polyether modified glass fibers.

7. The reinforced aerogel-modified polyurethane foam insulation board according to claim 1, characterized in that, The concentration of the dopamine hydrochloride solution is 1.5~3 g / L, and the solvent of the dopamine hydrochloride solution is a Tris-HCl buffer solution with pH=8.5~10.

8. The reinforced aerogel-modified polyurethane foam insulation board according to claim 1, characterized in that, The polyol is composed of flame-retardant aromatic polyether polyol and aromatic polyester polyol in a mass ratio of 7:3 to 8:2; the foaming agent is obtained by compounding cyclopentane and 1-chloro-3,3,3-trifluoropropylene in a mass ratio of 1:1 to 1:2; the silicone oil foam stabilizer is a polyether-modified polysiloxane foam stabilizer; the composite catalyst is composed of N,N-dimethylcyclohexylamine and 1,3,5-tris(dimethylaminopropyl)hexahydrotriazine in a mass ratio of 1:1.5 to 1:2.

5.

9. A method for preparing a reinforced aerogel-modified polyurethane foam insulation board according to any one of claims 1 to 8, characterized in that, Includes the following steps: (1) Pre-dispersion: Take the raw materials in the indicated weight proportions, add the hybrid ceramic composite flame retardant and the modified silica aerogel to the polyol in sequence, disperse evenly, and obtain a dispersion; (2) Constructing a three-dimensional framework: Add modified glass fiber to the dispersion, stir and mix to obtain component A premix; (3) Curing and foaming: Add water, foaming agent, stabilizer and composite catalyst to component A premix in sequence, stir evenly, add component B, mix at high speed and quickly pour into mold; (4) Curing and maturation: Curing and molding at a constant temperature of 45~60℃ for 22~28h, demolding and cutting to obtain reinforced aerogel modified polyurethane foam insulation board.

10. The method for preparing a reinforced aerogel-modified polyurethane foam insulation board according to claim 9, characterized in that, In step (1), the dispersion is carried out by a high-shear emulsifier with a speed of 3000~5000 r / min and a time of 15~20 min; in step (2), the mixing is carried out by a planetary mixer with a mixing speed of 50~100 r / min and a mixing time of 25~35 min; in step (3), the high-speed mixing speed is 1500~2000 r / min and the time is 6~10 s.

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