Glass fiber reinforced SiO2 aerogel composite fireproof material and preparation method thereof

Abstract

The application provides a glass fiber reinforced SiO2 aerogel composite fireproof material and a preparation method thereof, and relates to the technical field of fireproof materials. The preparation method comprises the following steps: (preparing a silicon source sol: mixing an organic silicon source and / or an inorganic silicon source, a solvent, water, a catalyst and a functional filler to obtain a precursor sol); (pretreating a glass fiber reinforced framework: removing impurities, activating, wetting or surface coupling treating the glass fiber reinforced framework); (impregnating a composite: impregnating the pretreated glass fiber reinforced framework in the precursor sol); (gelation and aging treatment: performing gelation treatment on the impregnated composite system, and performing aging treatment after the gelation treatment); (solvent exchange and hydrophobic modification treatment); (atmospheric pressure staged drying treatment: drying the modified composite wet gel under atmospheric pressure by staged temperature rising); and (post-treatment forming, to obtain a plate type or roll felt type composite thermal insulation fireproof material).

Description

Technical Field

[0001] This application belongs to the field of fireproof materials technology, and in particular relates to a glass fiber reinforced SiO2 aerogel composite fireproof material and its preparation method. Background Technology

[0002] SiO2 aerogel is a type of lightweight inorganic porous material with a three-dimensional nano-network structure and high porosity. It has low density, low thermal conductivity, high fire safety and excellent temperature resistance, and has broad application prospects in building energy conservation, industrial insulation, cryogenic equipment and special insulation fields.

[0003] However, existing technologies still have the following shortcomings: First, at present, a large number of high-performance SiO2 aerogels or their composite felt products still rely on supercritical drying, which involves high equipment investment, high energy consumption, complex processes, and high preparation costs, making it unfavorable for the promotion and application of large-area enclosure insulation scenarios such as cold chain storage and indoor ice and snow venues. Although there are atmospheric pressure drying solutions, the gel is prone to volume shrinkage, skeleton collapse, and cracking due to capillary forces during atmospheric pressure drying, resulting in severe deterioration of thermal conductivity, mechanical properties, and dimensional stability. Second, existing glass fiber reinforced SiO2 aerogel composite materials emphasize thermal conductivity, hydrophobicity, and temperature resistance indicators, but lack integrated material design and supporting indicator constraints for engineering applications, particularly for key low-temperature environments such as vapor barrier performance, anti-condensation performance, low-temperature dimensional stability, thermal retention rate after freeze-thaw cycles, portability of irregularly shaped covering construction, and fire resistance.

[0004] Therefore, there is an urgent need to develop a low-cost glass fiber reinforced SiO2 aerogel composite thermal insulation and fireproofing material suitable for low-temperature environments and its preparation method, so that it can retain the excellent comprehensive performance of SiO2 aerogel while achieving low thermal conductivity, high fire safety, hydrophobicity and moisture resistance, shrinkage resistance, freeze-thaw resistance, and dual-form engineering applications of boards / rolls. Summary of the Invention

[0005] The purpose of this application is to provide a glass fiber reinforced SiO2 aerogel composite fireproof material and its preparation method, aiming to solve the problem of high manufacturing cost of high-performance SiO2 aerogel or its composite felt products in the prior art.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a method for preparing a glass fiber reinforced SiO2 aerogel composite fireproof material, comprising the following steps: (1) Preparation of silicon source sol: Mix organosilicon source and / or inorganic silicon source, solvent, water, catalyst and functional filler to obtain precursor sol; (2) Pretreatment of glass fiber reinforced skeleton: The glass fiber reinforced skeleton is subjected to impurity removal, activation, wetting and / or surface coupling treatment; (3) Impregnation and composite: The pretreated glass fiber reinforced skeleton is impregnated in the precursor sol; (4) Gelation and aging treatment: The impregnated composite system is gelled and then aged in an oven. (5) Solvent exchange and hydrophobic modification: The wet gel is subjected to solvent exchange with organic solvent and surface hydrophobic treatment is performed using hydrophobic modifier; (6) Atmospheric pressure staged drying treatment: The modified composite wet gel is dried in stages under atmospheric pressure. The atmospheric pressure staged drying treatment includes a low temperature pre-drying stage, a medium temperature slow-release stage and a higher temperature enhanced drying stage. The temperature of the low temperature pre-drying stage is 35-40℃, the temperature of the medium temperature slow-release stage is 50-60℃, and the temperature of the higher temperature enhanced drying stage is 70-120℃. (7) Post-processing molding: The dried composite material is cut, pressed to a certain thickness, coated and laminated, edge treated or rolled up to obtain a plate-type or felt-type composite fireproof material.

[0007] In one or more embodiments of this application, the step of preparing the silicon source sol further includes: adding one or more organosilicon sources, anhydrous ethanol, and deionized water to a reaction vessel, stirring until homogeneous, adjusting the pH with hydrochloric acid, and then hydrolyzing with magnetic stirring to obtain an organosilicon source pre-hydrolyzed solution; and / or, One or more inorganic silicon sources are diluted with deionized water and acidified using a hydrochloric acid-activated cation exchange resin column to obtain an inorganic silicon source hydrolysate. Use organosilicon source pre-hydrolyzed solution and / or inorganic silicon source hydrolyzed solution as precursor sol.

[0008] In one or more embodiments of this application, the method further includes adding an anti-shrinkage additive to the system prior to step (4), wherein the anti-shrinkage additive is selected from one or more of silicon micro powder, fumed silica, micron-sized silica particles, inorganic nanoparticles, and ceramic micro powder.

[0009] In one or more embodiments of this application, in step (1), the organosilicon source is selected from one or more of tetraethyl orthosilicate, methyltriethoxysilane, and methyltrimethoxysilane, and the inorganic silicon source is selected from one or more of water glass and silica sol.

[0010] In one or more embodiments of this application, in step (2), the glass fiber reinforced skeleton is selected from one or more of glass fiber mat, ultrafine glass fiber mat, glass fiber paper, glass fiber cloth, and glass fiber needle-punched mat.

[0011] In one or more embodiments of this application, in step (5), the hydrophobic modifier is selected from one or more of trimethylchlorosilane, hexamethyldisilazane, methyltriethoxysilane, methyltrimethoxysilane, and silane coupling agents.

[0012] In one or more embodiments of this application, when the prepared composite fireproof material is a plate type, the preparation method further includes: applying an inorganic adhesive to the surface, edges and / or interlayer of the composite after step (5), and performing light pressing and / or coating composite treatment, wherein the inorganic adhesive includes silica sol.

[0013] Secondly, this application also provides a glass fiber reinforced SiO2 aerogel composite fireproof material, prepared by the preparation method described in any one of the first aspects. The composite fireproof material includes a SiO2 aerogel phase and a glass fiber reinforced skeleton, with a mass ratio of SiO2 aerogel phase to glass fiber reinforced skeleton of 10:90 to 60:40. The composite fireproof material is a plate-type or felt-type composite structure composed of the SiO2 aerogel phase and the glass fiber reinforced skeleton.

[0014] In one or more embodiments of this application, the composite fire-retardant material further includes an anti-shrinkage additive, which is dispersed in the SiO2 aerogel phase and / or distributed in the interface region between the SiO2 aerogel phase and the glass fiber reinforced skeleton.

[0015] In one or more embodiments of this application, the composite fire-retardant material has a thermal conductivity of 0.018~0.046 W / (m·K) at room temperature, and / or, The static water contact angle of the composite fireproof material is 120-155°, and / or, The composite fireproof material has a 24-hour water absorption rate of no more than 4 wt%, and / or, After being treated at a low temperature of -18°C or less, the composite fireproof material exhibits a compressive strength reduction rate of no more than 10%, and / or, The thickness change rate of the composite fireproof material after 25 freeze-thaw cycles is no greater than 2.5%, and the thermal conductivity retention rate of the composite fireproof material after 25 freeze-thaw cycles is no less than 85%; and / or, The apparent density of the composite fire-retardant material is 80-220 kg / m³. 3 .

[0016] In one or more embodiments of this application, the composite fireproof material further includes one or more of the following: a surface protective layer, a vapor barrier layer, a protective layer, a finishing layer, and an adhesive fixing layer.

[0017] Based on the above technical solutions, the glass fiber reinforced SiO2 aerogel composite fireproof material and its preparation method provided in this application have at least the following beneficial technical effects: The preparation method of this application uses a low-cost route of organic / inorganic silicon source coupling or organic or inorganic silicon source to prepare silicon source sol, which is then network-composite with a pretreated glass fiber reinforced skeleton, gelled and aged, followed by solvent exchange and hydrophobic modification treatment, and then combined with an atmospheric pressure graded drying process. After post-treatment molding, a plate-type or felt-type composite thermal insulation and fireproof material is obtained. The composite fireproof material prepared by the preparation method of this application can effectively suppress shrinkage, cracking and pulverization problems during the atmospheric pressure drying process, improve the integrity, dimensional stability and construction tolerance of the composite material, reduce equipment investment and manufacturing costs, and improve the feasibility of large-scale preparation.

[0018] The glass fiber reinforced SiO2 aerogel composite fireproof material prepared by the method of this application is a plate-type or roll-type composite structure composed of SiO2 aerogel phase and glass fiber reinforced skeleton. The resulting material maintains low thermal conductivity and high fire safety while also possessing hydrophobic, moisture-proof, anti-condensation, and freeze-thaw resistance properties.

[0019] The material obtained by this invention is suitable for low-temperature environments such as cold chain warehouses, indoor ice and snow venues, and warehouses in cold regions. It can be widely used as an energy-saving enclosure material that combines heat preservation, fireproofing, moisture resistance, and durability. Furthermore, it can be manufactured into self-supporting board-type products and roll-up felt-type products that can be rolled up and laid according to engineering needs, facilitating large-area enclosure laying, covering irregular parts, and treating cold bridges at joints, thus exhibiting good engineering adaptability. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A digital photograph of the rolled-up glass fiber reinforced SiO2 aerogel composite thermal insulation and fireproof material provided in Embodiment 1 of this application.

[0022] Figure 2 A digital photograph of the sheet-type glass fiber reinforced SiO2 aerogel composite thermal insulation and fireproofing material provided in Embodiment 3 of this application. Detailed Implementation

[0023] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0024] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0025] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0026] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0027] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0028] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass described in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0029] In a first aspect, this application provides a method for preparing a glass fiber reinforced SiO2 aerogel composite fireproof material, comprising the following steps: (1) Preparation of silicon source solution: Mix organic and / or inorganic silicon sources, solvents, water, catalysts and various types of functional fillers to obtain precursor mixed sol.

[0030] The specific steps for preparing the silicon source solution include: adding one or more organosilicon sources, anhydrous ethanol, and deionized water to a reaction vessel, stirring thoroughly, adjusting the pH with hydrochloric acid, and then hydrolyzing with magnetic stirring to obtain a pre-hydrolyzed organosilicon source solution; and / or, One or more inorganic silicon sources are diluted with deionized water and acidified using a hydrochloric acid-activated cation exchange resin column to obtain an inorganic silicon source hydrolysate. Use organosilicon source pre-hydrolyzed solution and / or inorganic silicon source hydrolyzed solution as precursor sol.

[0031] (2) Pretreatment of glass fiber reinforced skeleton: The glass fiber reinforced skeleton is subjected to impurity removal, activation, wetting or surface coupling treatment to improve the wettability of the fiber surface, the interfacial bonding strength and the uniformity of sol wetting.

[0032] (3) Impregnation and composite: The pretreated glass fiber reinforced skeleton is impregnated in the precursor sol, so that the sol can fully penetrate into the pores of the fiber skeleton. Preferably, impregnation, vacuum-assisted impregnation, roller impregnation or spray-impregnation coupling method can be used to improve the uniformity of sol wetting of fiber skeleton.

[0033] (4) Gelation and aging treatment: The impregnated composite system is gelled and aged to enhance the strength of the wet gel skeleton. The pore structure, shrinkage rate and mechanical stability of the composite material can be controlled by adjusting the pH, gelation time and aging time of the system. Gelation is carried out by acid catalysis, base catalysis or two-step acid-base catalysis.

[0034] (5) Solvent exchange and hydrophobic modification: The wet gel is solvent exchanged with organic solvent and the surface is hydrophobically treated with hydrophobic modifier.

[0035] (6) Staged Drying at Normal Pressure: The modified composite wet gel is dried in stages under normal pressure to reduce capillary shrinkage and skeleton collapse. Staged drying at normal pressure includes a low-temperature pre-drying stage, a medium-temperature slow-release stage, and a high-temperature intensive drying stage. The low-temperature pre-drying stage is used to slowly release the pore liquid and reduce rapid surface shrinkage, while the medium- and high-temperature intensive drying stage is used to remove residual solvent and solidify the hydrophobic structure. The temperature of the low-temperature pre-drying stage is 35-40℃, the temperature of the medium-temperature slow-release stage is 50-60℃, and the temperature of the high-temperature intensive drying stage is 70-120℃.

[0036] (7) Post-processing molding: The dried composite material is cut, pressed to a certain thickness, coated and laminated, edge treated or rolled up to obtain a plate-type or felt-type composite fireproof material.

[0037] Preferably, in order to further suppress the shrinkage during normal pressure drying and improve the structural stability, an anti-shrinkage additive is added to the system before step (4). The anti-shrinkage additive is selected from one or more of the following: silica powder, fumed silica, micron-sized silica particles, inorganic nanoparticles, and ceramic powder.

[0038] Preferably, when the prepared composite fireproof material is a plate type, the preparation method further includes: applying an inorganic adhesive to the surface, edges and / or interlayer of the composite after step (5), and performing light pressing and / or coating composite treatment, wherein the inorganic adhesive includes silica sol. Furthermore, the inorganic adhesive also includes one or more of alumina sol and refractory fillers.

[0039] Preferably, the organosilicon source is selected from one or more of tetraethyl orthosilicate, methyltriethoxysilane, and methyltrimethoxysilane; the inorganic silicon source is selected from one or more of water glass and silica sol.

[0040] Preferably, the glass fiber reinforced skeleton is selected from one or more of glass fiber mat, ultrafine glass fiber mat, glass fiber paper, glass fiber cloth, and glass fiber needle-punched mat.

[0041] Preferably, the hydrophobic modifier is selected from one or more of trimethylchlorosilane, hexamethyldisilazane, methyltriethoxysilane, methyltrimethoxysilane, and silane coupling agents.

[0042] Preferably, to further improve the temperature resistance, dimensional stability, mechanical strength and construction compatibility of the composite material, the functional filler may also include one or more of rare earth metals, infrared shielding fillers, reinforcing filler components, inorganic binder components and surface coatings, so as to further improve the temperature resistance, thermal conductivity, mechanical properties, anti-dust properties, durability and construction compatibility.

[0043] In a second aspect, this application provides a glass fiber reinforced SiO2 aerogel composite fireproof material prepared by any of the preparation methods of the first aspect. The composite fireproof material includes a SiO2 aerogel phase and a glass fiber reinforced skeleton, wherein the mass ratio of the SiO2 aerogel phase to the glass fiber reinforced skeleton is 10:90 to 60:40, and it is a plate-type or felt-type composite structure composed of the SiO2 aerogel phase and the glass fiber reinforced skeleton.

[0044] Preferably, the SiO2 aerogel phase can be formed from an organosilicon source and / or an inorganic silicon source via a sol-gel reaction, followed by aging, solvent exchange, hydrophobic modification, and atmospheric pressure graded drying. A glass fiber reinforced skeleton is used to support the aerogel nanonetwork, inhibit drying shrinkage, and improve the overall formability, dimensional stability, and low-temperature service reliability of the material. The resulting composite material can be manufactured in sheet or felt form, suitable for cold chain warehouses, indoor ice and snow venues, cold-region warehouses, the outer walls of refrigeration and freezing equipment, low-temperature pipelines, and other low-temperature environments.

[0045] Preferably, the organosilicon source is selected from one or more of tetraethyl orthosilicate, methyltriethoxysilane, and methyltrimethoxysilane, and the inorganic silicon source is selected from one or more of water glass and silica sol.

[0046] Preferably, the glass fiber reinforced skeleton is selected from one or more of glass fiber mat, ultrafine glass fiber mat, glass fiber paper, glass fiber cloth, and glass fiber needle-punched mat.

[0047] Preferably, the composite fireproof material further includes an anti-shrinkage additive, which is dispersed in the SiO2 aerogel phase and / or distributed in the interface region between the SiO2 aerogel phase and the glass fiber reinforced skeleton.

[0048] Preferably, the anti-shrinkage additive is selected from one or more of the following: silicon micro powder, fumed SiO2, micron-sized SiO2 particles, inorganic nanoparticles, and ceramic micro powder.

[0049] Preferably, the thermal conductivity of the composite fireproof material at room temperature is 0.018~0.046 W / (m·K), and more preferably, the thermal conductivity of the composite fireproof material at room temperature is 0.020~0.035 W / (m·K).

[0050] Preferably, the static water contact angle of the composite fireproof material is 120-155°. More preferably, the static water contact angle of the composite fireproof material is 130-155°.

[0051] Preferably, the water absorption rate of the composite fireproof material in 24 hours is not higher than 4 wt%. More preferably, it is not higher than 2.5 wt%.

[0052] Preferably, the compressive strength reduction rate of the composite fireproof material after low-temperature treatment at -18°C or below is no more than 10%. More preferably, it is no more than 5%.

[0053] Preferably, the thickness change rate of the composite fireproof material after 25 freeze-thaw cycles is no more than 2.5%. More preferably, it is no more than 1.5%.

[0054] Preferably, the composite fire-retardant material retains a thermal conductivity of not less than 85% after 25 freeze-thaw cycles. More preferably, not less than 90%.

[0055] Preferably, the apparent density of the composite fire-retardant material is 80-220 kg / m³. 3 More preferably, the apparent density of the composite fireproof material is 100–180 kg / m³.

[0056] Preferably, the thickness of the composite fireproof material is 3-40 mm; wherein, the thickness of the composite fireproof material for rolled felt products is 3-15 mm, and the thickness of the composite fireproof material for sheet products is 5-30 mm.

[0057] Preferably, the panel-type composite fireproof material also includes an inorganic binder, the inorganic binder component being disposed on the surface / edge of the material, or used for interlayer bonding, fixed thickness and shape bonding, and surface coating bonding.

[0058] Preferably, the inorganic binder includes silica sol.

[0059] Furthermore, inorganic binders also include one or more of alumina sol and refractory fillers.

[0060] Preferably, in order to further improve the temperature resistance, dimensional stability, mechanical strength and construction adaptability of the composite material, the composite fireproof material system may also include one or more of rare earth metals, infrared shielding fillers, reinforcing filler components, inorganic binder components and surface coatings.

[0061] Preferably, the composite fireproof material further includes one or more of the following: a surface protective layer, a vapor barrier layer, a protective layer, a finishing layer, and an adhesive layer. The vapor barrier layer is selected from one or more of the following: aluminum foil composite film, PET / aluminum foil composite barrier film, EVOH barrier film, fluoropolymer barrier film, or inorganic-organic hybrid barrier layer.

[0062] The composite fireproof material of this application is a self-supporting board-type product or a roll-up felt-type product that can be rolled and laid. The board-type product has good self-support and dimensional stability; the roll-up felt-type product has a certain degree of flexibility and rollability, and is suitable for irregular shape covering, joint laying and continuous roll-up construction.

[0063] Preferably, the compressive strength of the sheet material is 0.10-0.80 MPa.

[0064] The composite material of this application possesses low thermal conductivity, hydrophobicity, moisture resistance, condensation prevention, freeze-thaw resistance, dimensional stability, and fire resistance. It can be applied to cold chain warehouse enclosure structures, refrigerated and frozen storage enclosure structures, indoor ice and snow venue enclosure structures, cold region warehouse enclosure structures, refrigerated transport containers, cryogenic equipment exterior walls, cryogenic pipelines, and other cryogenic insulation and fireproofing applications. This composite fireproof material can be used alone or in conjunction with vapor barriers, waterproof layers, finishing layers, protective layers, or fixing layers.

[0065] The following description is based on specific embodiments.

[0066] Example 1 In this embodiment, a roll-type flexible composite fireproof material is prepared by using a composite silicon source of tetraethyl orthosilicate (TEOS) / water glass, a glass fiber felt skeleton, and hydrophobic modification with the hydrophobic modifier trimethylchlorosilane (TMCS).

[0067] First, 0.1 mol tetraethyl orthosilicate (TEOS), 0.05 mol methyltrimethoxysilane (MTMS), 1 mol anhydrous ethanol, and 0.4 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.5 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 65 °C for 3 h to obtain an organosilicon source pre-hydrolyzed solution. Separately, industrial water glass with a modulus of 3.2 was diluted 8 times with deionized water and passed through a hydrochloric acid-activated cation exchange resin column to collect a water glass hydrolysate at pH 1.5. The organosilicon source pre-hydrolyzed solution and the water glass hydrolysate were mixed at a theoretical SiO2 mass ratio of 7:3 and stirred for another 20 min.

[0068] A thickness of 10 mm and a surface density of 200 g / m³ 2 The glass fiber mat was cut into 100 mm × 100 mm pieces, washed twice with anhydrous ethanol and dried, then immersed in 1.5 wt% KH550 ethanol solution for 20 min, and dried at 80 ℃ for 30 min after impregnation.

[0069] The pH of the mixed sol was then adjusted to 9 with 0.5 mol / L ammonia solution, and quickly poured into a polytetrafluoroethylene mold with fiberglass mat laid flat, ensuring the liquid surface completely submerged the fiberglass mat. The mixture was then ultrasonically dispersed in a sealed bag for 2 minutes and allowed to stand at room temperature for 25 minutes to gel. After gelation, it was aged in a 60℃ forced-air oven for 12 hours. Hydrophobic modification was then performed for 6 hours using a 1:4 volume ratio mixture of trimethylchlorosilane (TMCS) and n-hexane, with two replacements using n-hexane.

[0070] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 60 ℃ for 6 h, 80 ℃ for 4 h, and 120 ℃ for 4 h, to obtain glass fiber reinforced SiO2 aerogel composite material.

[0071] A digital photograph of the felt-type glass fiber reinforced SiO2 aerogel composite thermal insulation and fireproof material prepared in this embodiment is shown below. Figure 1 As shown, the apparent density of the composite material prepared in this embodiment is 126 kg / m³. 3The thermal conductivity is 0.024 W / (m·K), the thickness of the composite material is 10 mm, the static water contact angle is 148°, the water absorption rate in 24 h is 2.1 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18℃) is <7%, the thickness change rate after 25 freeze-thaw cycles is 0.8%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 95%.

[0072] Example 2 In this embodiment, a plate-type composite material is prepared by using water glass as the main silicon source, methyltriethoxysilane (MTES) as the auxiliary organosilicon source, glass fiber paper / glass fiber mat composite skeleton, and hydrophobic modification with hexamethyldisilazane (HMDS).

[0073] First, industrial water glass with a modulus of 3.2 was diluted 10 times with deionized water and passed through a cation exchange resin column activated with hydrochloric acid to collect a silicic acid solution with a pH of 1.2 for later use. Simultaneously, 0.08 mol of methyltriethoxysilane (MTES), 0.64 mol of anhydrous ethanol, and 0.24 mol of deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 4.5 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 45 °C for 1.5 h to obtain a pre-hydrolyzed organosilicon source solution. Subsequently, the pre-hydrolyzed organosilicon source solution was slowly added to the silicic acid solution and stirred for 15 min to obtain a precursor mixed sol.

[0074] 0.3 mm thick glass fiber paper is laminated with 8 mm thick glass fiber mat, cut into 100 mm × 100 mm pieces, washed twice with anhydrous ethanol and dried for later use.

[0075] The pH of the mixed sol was then adjusted to 6.5 with 0.5 mol / L ammonia solution, and quickly poured into a polytetrafluoroethylene mold with a composite glass fiber skeleton laid flat, ensuring the liquid surface completely submerged the glass fiber skeleton. The mixture was allowed to stand at room temperature for 35 min to gel. After gelation, it was aged in a 60 ℃ forced-air oven for 12 h. Then, hydrophobic modification was performed for 8 h using a 1:5 volume ratio mixture of hexamethyldisilazane (HMDS) / n-hexane, with three replacement cycles using n-hexane.

[0076] After hydrophobic modification, an inorganic adhesive slurry is uniformly sprayed onto the surface of the wet gel composite. The inorganic adhesive is composed of silica sol, alumina sol and deionized water in a mass ratio of 80:5:15, wherein the alumina sol accounts for 5 wt% of the total mass of the inorganic adhesive slurry. The spraying amount is 80-120 g / m². After spraying, the material is placed between molding plates and lightly pressed for 5 minutes to improve the integrity and edge integrity of the board.

[0077] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 60 ℃ for 6 h, 80 ℃ for 4 h, and 120 ℃ for 4 h, to obtain a plate-type glass fiber reinforced SiO2 aerogel composite material.

[0078] The apparent density of the composite material prepared in this embodiment is 152 kg / m³. 3 The thermal conductivity is 0.029 W / (m·K), the thickness is 15 mm, the static water contact angle is 139°, the water absorption rate in 24 h is 3.2 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18℃) is <5%, the thickness change rate after 25 freeze-thaw cycles is 1.4%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 91%.

[0079] Example 3 In this embodiment, a plate-type composite material is prepared by using tetraethyl orthosilicate (TEOS) as the main silicon source, a thick glass fiber felt skeleton, and hydrophobic modification by compounding trimethylchlorosilane (TMCS) / hexamethyldisilazane (HMDS).

[0080] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.02 mol methyltrimethoxysilane (MTMS), 1.2 mol anhydrous ethanol and 0.45 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.2 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 65 °C for 3 h for hydrolysis. After hydrolysis was completed, the pH of the system was adjusted to 8.2 with 0.5 mol / L ammonia to obtain a gelable precursor sol.

[0081] Glass fiber mat with a thickness of 12 mm and a surface density of 260 g / m² was cut into 100 mm × 100 mm pieces. It was first washed twice with anhydrous ethanol and dried, then immersed in 2.0 wt% KH550 ethanol solution for 20 min. After impregnation, it was dried at 80 ℃ for 30 min.

[0082] The mixed sol was then rapidly poured into a PTFE mold with fiberglass mat laid flat, ensuring the liquid completely submerged the mat. It was then ultrasonically dispersed in a sealed bag for 2 minutes and allowed to gel at room temperature for 20 minutes. After gelation, it was aged in a 60 °C oven for 12 hours. Hydrophobic modification was then performed for 8 hours using a 1:1:8 volume ratio TMCS / HMDS / n-hexane mixture, with three replacement cycles using n-hexane.

[0083] After hydrophobic modification, an inorganic binder slurry is roller-coated onto the surface and edges of the composite. The inorganic binder slurry is a mixture of silica sol, refractory filler, and deionized water in a mass ratio of 85:5:10. The refractory filler is alumina micropowder and / or mullite powder, with a particle size of 1–10 μm. The total amount of inorganic binder slurry used for roller coating on the surface and edges of the composite is 100–150 g / m². 2 This enhances the shaping ability and anti-dust properties of the board.

[0084] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 35 ℃ for 3 h, 50 ℃ for 4 h, 70 ℃ for 6 h, 90 ℃ for 4 h, and 120 ℃ for 4 h, to obtain a plate-type glass fiber reinforced SiO2 aerogel composite material.

[0085] Digital photograph of the plate-type glass fiber reinforced SiO2 aerogel composite thermal insulation and fireproof material prepared in this embodiment, as shown below. Figure 2 As shown. The apparent density of the composite material prepared in this embodiment is 112 kg / m³. 3 The thermal conductivity is 0.022 W / (m·K), the thickness is 12 mm, the static water contact angle is 146°, the water absorption rate in 24 h is 1.6 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18 ℃) is <6%, the thickness change rate after 25 freeze-thaw cycles is 0.6%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 96%.

[0086] Example 4 In this embodiment, a low-viscosity composite silicon source system and ultrafine glass fiber mat are used to prepare a roll-type flexible composite material.

[0087] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.07 mol methyltrimethoxysilane (MTMS), 1.4 mol anhydrous ethanol, and 0.50 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.8 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 60 °C for 2.5 h to obtain an organosilicon source pre-hydrolyzed solution. Separately, industrial water glass was diluted and acidified with a cation exchange resin to prepare a water glass hydrolyzed solution with a pH of 1.5. This solution was then mixed with the pre-hydrolyzed solution at a theoretical SiO2 mass ratio of 8:2, and stirred for another 15 min. Subsequently, the pH of the system was adjusted to 7.2 with 0.5 mol / L ammonia water to obtain a low-viscosity precursor sol.

[0088] Cut 5 mm thick ultrafine glass fiber mat into 100 mm × 100 mm pieces, wash twice with anhydrous ethanol and dry for later use.

[0089] The precursor sol was poured into a polytetrafluoroethylene mold with ultrafine glass fiber mat laid flat, so that the liquid surface completely submerged the glass fiber mat. It was then ultrasonically dispersed in a sealed bag for 1 min and allowed to stand at room temperature for 30 min to gel. After gelation, it was aged in a 60 ℃ forced-air oven for 12 h.

[0090] Then, hydrophobic modification was performed for 6 hours using a mixture of hexamethyldisilazane (HMDS) and n-hexane at a volume ratio of 1:5, followed by two replacements with n-hexane.

[0091] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 55 ℃ for 5 h, 75 ℃ for 4 h, and 110 ℃ for 4 h, to obtain a rolled-up glass fiber reinforced SiO2 aerogel composite material.

[0092] The apparent density of the composite material prepared in this embodiment is 105 kg / m³. 3 The thermal conductivity is 0.026 W / (m·K), the thickness is 5 mm, the static water contact angle is 136°, the water absorption rate in 24 h is 2.7 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18 ℃) is <10%, the thickness change rate after 25 freeze-thaw cycles is 1.1%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 92%.

[0093] Example 5 In this embodiment, the degree of hydrophobic modification is increased based on Example 4. A highly hydrophobic felt-type flexible composite material is prepared by using a compound hydrophobic modification of hexamethyldisilazane (HMDS) / methyltrimethoxysilane (MTMS).

[0094] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.09 mol methyltrimethoxysilane (MTMS), 1.2 mol anhydrous ethanol and 0.40 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.5 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 60 °C for 2.5 h for hydrolysis. After hydrolysis was completed, the pH of the system was adjusted to 8.0 with 0.5 mol / L ammonia to obtain the precursor sol.

[0095] The 6 mm thick ultrafine glass fiber mat was cut into 100 mm × 100 mm pieces, washed twice with anhydrous ethanol and dried, and then immersed in 1.0 wt% KH550 ethanol solution for 20 min. After impregnation, it was dried at 80 ℃ for 30 min.

[0096] The mixed sol was then rapidly poured into a PTFE mold with fiberglass mat laid flat, ensuring the liquid completely submerged the mat. It was then ultrasonically dispersed in a sealed bag for 2 minutes and allowed to gel at room temperature for 25 minutes. After gelation, it was aged in a 60 °C forced-air oven for 12 hours. Hydrophobic modification was then performed for 8 hours using a 1:1:8 volume ratio HMDS / MTMS / n-hexane mixture, with three replacement cycles using n-hexane.

[0097] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 60 ℃ for 6 h, 80 ℃ for 4 h, and 120 ℃ for 4 h, to obtain a highly hydrophobic felt-type glass fiber reinforced SiO2 aerogel composite material.

[0098] The apparent density of the composite material prepared in this embodiment is 98 kg / m³. 3 The thermal conductivity is 0.028 W / (m·K), the thickness is 6 mm, the static water contact angle is 154°, the water absorption rate in 24 h is 1.3 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18 ℃) is <10%, the thickness change rate after 25 freeze-thaw cycles is 0.8%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 94%.

[0099] Example 6 In this embodiment, silicon micropowder is added to the silicon source sol as an anti-shrinkage additive to prepare a sheet-type composite material.

[0100] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.04 mol methyltrimethoxysilane (MTMS), 1.0 mol anhydrous ethanol, and 0.40 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.5 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 65 °C for 3 h for hydrolysis. Separately, industrial water glass was diluted and acidified to prepare a water glass hydrolysate, which was then mixed with an organosilicon source pre-hydrolysate at a theoretical SiO2 mass ratio of 6:4. Subsequently, 8 wt% (relative to the theoretical SiO2 mass) of silica powder was added to the mixed sol, and the mixture was dispersed at high speed for 10 min. The pH of the system was then adjusted to 7.8 with 0.5 mol / L ammonia.

[0101] The 12 mm thick glass fiber mat was cut into 100 mm × 100 mm pieces, washed twice with anhydrous ethanol and dried, and then immersed in 1.5 wt% KH550 ethanol solution for 20 min. After impregnation, it was dried at 80 ℃ for 30 min.

[0102] The mixed sol was then quickly poured into a polytetrafluoroethylene mold with fiberglass mat laid flat, ensuring the liquid surface completely submerged the fiberglass mat. The mixture was allowed to stand at room temperature for 25 minutes to gel. After gelation, it was aged in a 60 °C forced-air oven for 12 h. Then, hydrophobic modification was performed for 6 h using a 1:4 volume ratio mixture of hexamethyldisilazane (HMDZ) / n-hexane, followed by two replacements with n-hexane.

[0103] After hydrophobic modification, an inorganic adhesive slurry is uniformly sprayed onto the material surface at a rate of 100–130 g / m². 2 Then, gently press and shape it between the flat molds for 5 minutes.

[0104] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 60 ℃ for 6 h, 80 ℃ for 4 h, and 120 ℃ for 4 h, to obtain a plate-type glass fiber reinforced SiO2 aerogel composite material.

[0105] The apparent density of the composite material prepared in this embodiment is 148 kg / m³. 3 The thermal conductivity is 0.028 W / (m·K), the thickness is 12 mm, the static water contact angle is 139°, the water absorption rate in 24 h is 2.4 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18℃) is <8%, the thickness change rate after 25 freeze-thaw cycles is 0.7%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 94%.

[0106] Example 7 In this embodiment, fumed SiO2 is used as an anti-shrinkage additive, and a flexible glass fiber needle-punched felt skeleton is used to prepare a roll-type flexible composite material.

[0107] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.06 mol methyltrimethoxysilane (MTMS), 1.1 mol anhydrous ethanol and 0.40 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.6 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 60 °C for 2.5 h for hydrolysis. Subsequently, 5 wt% of gaseous SiO2 relative to the theoretical SiO2 mass was added, and the mixture was dispersed at high speed for 15 min. The pH of the system was then adjusted to 7.5 with 0.5 mol / L ammonia.

[0108] Cut 5 mm thick glass fiber needled felt into 100 mm × 100 mm pieces, wash twice with anhydrous ethanol and dry for later use.

[0109] The mixed sol was then poured into a mold with fiberglass needle-punched felt laid flat, so that the liquid surface completely submerged the fiber skeleton, and impregnated at normal pressure for 3 minutes, followed by vacuum-assisted penetration for 1 minute, and allowed to stand at room temperature for 30 minutes to gel; after gelation, it was aged in a 60 ℃ forced-air oven for 12 hours.

[0110] Then, hydrophobic modification was performed for 6 hours using a mixture of hexamethyldisilazane (HMDS) and n-hexane at a volume ratio of 1:5, and the mixture was replaced with n-hexane 3 times.

[0111] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 55 ℃ for 5 h, 75 ℃ for 4 h, and 110 ℃ for 4 h, to obtain a rolled-up glass fiber reinforced SiO2 aerogel composite material.

[0112] The apparent density of the composite material prepared in this embodiment is 118 kg / m³. 3 The thermal conductivity is 0.027 W / (m·K), the thickness is 5 mm, the static water contact angle is 141°, the water absorption rate in 24 h is 2.0 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18 ℃) is <5%, the thickness change rate after 25 freeze-thaw cycles is 0.9%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 93%.

[0113] Example 8 In this embodiment, a multi-layer plate-type composite material is prepared by stepwise impregnation and composite with a double-layer glass fiber skeleton.

[0114] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.03 mol methyltrimethoxysilane (MTMS), 1.0 mol anhydrous ethanol, and 0.40 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.4 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 65 °C for 3 h for hydrolysis. Separately, industrial water glass was diluted and acidified to prepare a water glass hydrolysate, which was then mixed with an organosilicon source pre-hydrolysate at a theoretical SiO2 mass ratio of 7:3, and stirred for another 15 min. Finally, the pH of the system was adjusted to 7.6 with 0.5 mol / L ammonia.

[0115] Two 8 mm thick glass fiber mats were cut into 100 mm × 100 mm pieces. Each mat was first washed twice with anhydrous ethanol and dried, then immersed in a 1.5 wt% KH550 ethanol solution for 20 min. After impregnation, the mats were dried at 80 ℃ for 30 min. The first layer of glass fiber mat was laid flat in a mold, and a portion of the precursor sol was poured in for 10 min of impregnation. The second layer of glass fiber mat was then stacked on top, and more sol was added until the mats were completely submerged. The mixture was then ultrasonically dispersed in a sealed bag for 2 min and allowed to stand at room temperature for 35 min to gel. After gelation, the mixture was aged in a 60 ℃ forced-air oven for 12 h.

[0116] Then, hydrophobic modification was performed for 6 h using a trimethylchlorosilane (TMCS) / n-hexane mixture at a volume ratio of 1:4, followed by two replacements with n-hexane. After hydrophobic modification, an inorganic adhesive was applied to the surface of the composite and the interlayer edges to enhance the interlayer bonding and overall strength of the multilayer board.

[0117] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 60 ℃ for 6 h, 80 ℃ for 4 h, and 120 ℃ for 5 h, to obtain a multilayer plate-type glass fiber reinforced SiO2 aerogel composite material.

[0118] The apparent density of the composite material prepared in this embodiment is 168 kg / m³. 3 The thermal conductivity is 0.031 W / (m·K), the thickness is 18 mm, the static water contact angle is 134°, the water absorption rate in 24 h is 3.1 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18℃) is <10%, the thickness change rate after 25 freeze-thaw cycles is 1.2%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 91%.

[0119] Example 9 In this embodiment, a protective layer or barrier layer is further laminated onto the surface of the board to prepare a surface-coated board composite material.

[0120] First, a glass fiber reinforced SiO2 aerogel composite core layer with a thickness of 10 mm was prepared according to the method described in Example 1. Then, a 30 μm aluminum foil / PET composite protective film and a 0.15 mm glass fiber surface protective layer were respectively coated on both sides of the core layer. An inorganic adhesive was first sprayed onto the surface of the core layer at a spraying amount of 100–150 g / m². 2 Then, a coating process is performed; the coating temperature is 80℃, the pressure is 0.2 MPa, and the time is 5 min. After coating, the product is post-treated at 60℃ for 1 h.

[0121] The apparent density of the composite material prepared in this embodiment is 182 kg / m³. 3 The thermal conductivity is 0.032 W / (m·K), the total thickness is 12.4 mm, the static water contact angle is 137°, the water absorption rate in 24 h is 1.5 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18 ℃) is <8%, the thickness change rate after 25 freeze-thaw cycles is 0.8%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 94%.

[0122] Example 10 In this embodiment, a high freeze-thaw stable composite material for sheet materials is prepared by extending the aging time, optimizing the solvent exchange process, improving the degree of hydrophobic modification, and using anti-shrinkage additives.

[0123] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.05 mol methyltrimethoxysilane (MTMS), 1.0 mol anhydrous ethanol and 0.40 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.5 with 0.10 mol / L hydrochloric acid, and the mixture was magnetically stirred at 65 °C for 3 h for hydrolysis. 6 wt% of silica powder relative to the theoretical SiO2 mass was then added and dispersed at high speed for 10 min. Subsequently, the pH of the system was adjusted to 9 with 0.5 mol / L ammonia.

[0124] A 10 mm thick glass fiber mat was cut into 100 mm × 100 mm pieces, washed twice with anhydrous ethanol and dried, then immersed in a 1.5 wt% KH550 ethanol solution for 20 min. After impregnation, it was dried at 80 ℃ for 30 min.

[0125] The mixed sol was then quickly poured into a polytetrafluoroethylene mold with fiberglass mat laid flat, ensuring the liquid surface completely submerged the fiberglass mat. The mixture was allowed to stand at room temperature for 25 minutes to gel. After gelation, it was aged in a 60 °C forced-air oven for 48 h. Then, it was successively replaced with ethanol once and with n-hexane twice, each time for 2 h, followed by hydrophobic modification with a 1:4 volume ratio of hexamethyldisilazane (HMDZ) / n-hexane mixture for 10 h.

[0126] After hydrophobic modification, an inorganic adhesive is sprayed onto the surface of the composite and then lightly pressed to set the shape.

[0127] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 35 ℃ for 3 h, 50 ℃ for 6 h, 70 ℃ for 6 h, 90 ℃ for 4 h, and 120 ℃ for 4 h, to obtain a high freeze-thaw stable composite material.

[0128] The apparent density of the composite material prepared in this embodiment is 126 kg / m³. 3 The thermal conductivity is 0.023 W / (m·K), the thickness is 10 mm, the static water contact angle is 148°, the water absorption rate in 24 h is 1.4 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18℃) is <5%, the thickness change rate after 25 freeze-thaw cycles is 0.4%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 97%.

[0129] Example 11 In this embodiment, a vapor barrier layer is further laminated onto the warm side of the plate to obtain a vapor barrier composite plate material.

[0130] First, a 15 mm thick sheet-type glass fiber reinforced SiO2 aerogel composite core layer was prepared according to the method described in Example 2. Then, a 40 μm PET / aluminum foil composite vapor barrier was laminated to both sides of the sheet. An inorganic adhesive was first uniformly sprayed onto the surface of the core layer, followed by a hot-pressing lamination process at 85 °C, 0.25 MPa, and 4 min. Afterward, a post-treatment at 60 °C was performed for 1 h.

[0131] The composite material prepared in this embodiment has an apparent density of 168 kg / m3, a thermal conductivity of 0.028 W / (m·K), a total thickness of 15.2 mm, a static water contact angle of 140°, a 24-h water absorption rate of 1.0 wt%, a compressive strength attenuation rate of <7% after low-temperature treatment (≤-18 ℃), a thickness change rate of 0.7% after 25 freeze-thaw cycles, and a thermal conductivity retention rate of 95% after 25 freeze-thaw cycles.

[0132] Example 12 In this embodiment, a flexible glass fiber needle-punched felt skeleton is used and anti-shrinkage additives are added to obtain a flexible composite material that can be bent and wound.

[0133] First, 0.10 mol tetraethyl orthosilicate (TEOS), 0.08 mol methyltrimethoxysilane (MTMS), 1.2 mol anhydrous ethanol and 0.40 mol deionized water were added to a reaction vessel and stirred until homogeneous. The pH was then adjusted to 3.6 with 0.10 mol / L hydrochloric acid and hydrolyzed magnetically at 60 °C for 2.5 h. Subsequently, 4 wt% of fumed silica relative to the theoretical SiO2 mass was added and dispersed for 10 min. The pH of the system was then adjusted to 7.4 with 0.5 mol / L ammonia.

[0134] The 4 mm thick flexible glass fiber needled felt was cut into 100 mm × 100 mm pieces, washed twice with anhydrous ethanol and dried for later use.

[0135] The mixed sol was then poured into a mold with glass fiber needle-punched felt laid flat, so that the liquid surface completely submerged the fiber skeleton, and ultrasonically dispersed in a sealed bag for 1 min, and allowed to stand at room temperature for 30 min to gel; after gelation, it was aged in a 60 ℃ forced-air oven for 12 h.

[0136] Then, hydrophobic modification was carried out for 8 h using a mixture of hexamethyldisilazane (HMDS) / methyltrimethoxysilane (MTMS) / n-hexane in a volume ratio of 1:1:8, and the mixture was replaced with n-hexane 3 times.

[0137] Finally, a staged drying process at normal pressure was adopted, in which the materials were dried at 40 ℃ for 2 h, 55 ℃ for 5 h, 75 ℃ for 4 h, and 110 ℃ for 4 h, to obtain a rolled-up glass fiber reinforced SiO2 aerogel composite material.

[0138] The apparent density of the composite material prepared in this embodiment is 108 kg / m³. 3 The thermal conductivity is 0.026 W / (m·K), the thickness is 4 mm, the static water contact angle is 145°, the water absorption rate in 24 h is 1.8 wt%, the compressive strength attenuation rate after low temperature treatment (≤-18 ℃) is <10%, the thickness change rate after 25 freeze-thaw cycles is 0.8%, and the thermal conductivity retention rate after 25 freeze-thaw cycles is 93%.

[0139] Comparative Example 1 In this comparative example, except for the lack of hydrophobic modification, the composition of raw materials, feed ratio, glass fiber skeleton, pH adjustment, gelation conditions, aging conditions and graded drying regime were the same as in Example 1.

[0140] The method involves using a tetraethyl orthosilicate (TEOS) / water glass composite silicon source and a glass fiber mat skeleton. The pH of the mixed sol is adjusted to 9, and the gel is allowed to stand at room temperature for 25 min to gel. The gel is then aged at 60 ℃ for 12 h, dried at 40 ℃ for 2 h, 60 ℃ for 6 h, 80 ℃ for 4 h, and 120 ℃ for 4 h. However, the hydrophobic modification is not performed using a TMCS / n-hexane mixture.

[0141] The composite material prepared in this comparative example has a static water contact angle of 92°, a water absorption rate of 10.6 wt% in 24 h, a compressive strength decay rate of <15% after low temperature treatment (≤-18 ℃), a thickness change rate of 3.5% after 25 freeze-thaw cycles, and a thermal conductivity retention rate of 79% after 25 freeze-thaw cycles.

[0142] Comparative Example 2 In this comparative example, except for the absence of a glass fiber reinforced skeleton, the other process conditions were the same as in Example 1. That is, the same tetraethyl orthosilicate (TEOS) / water glass composite silicon source, the same acid-catalyzed hydrolysis conditions, the same pH adjustment conditions, the same hydrophobic modification, and the same atmospheric pressure staged drying regime were used. The only difference was that the glass fiber mat was not laid down, and the sol was directly poured into the mold for gelation, aging, modification, and drying.

[0143] Although the sample prepared in this comparative example was able to gel and form a block material, it exhibited significant shrinkage, edge cracking, and localized powdering during normal pressure drying. Its thermal conductivity was 0.037 W / (m·K), the compressive strength attenuation rate after low-temperature treatment (≤-18℃) was <20%, the thickness change rate after 25 freeze-thaw cycles was 5.4%, and the thermal conductivity retention rate after 25 freeze-thaw cycles was 74%.

[0144] Comparative Example 3 In this comparative example, the conditions were the same as in Example 6, except that no anti-shrinkage additive was added. That is, the same TEOS / MTMS / water glass composite silicon source system, the same glass fiber mat skeleton, the same pH control, the same HMDZ hydrophobic modification, and the same atmospheric pressure graded drying process were used, except that 8 wt% of silicon micropowder relative to the theoretical SiO2 mass was not added; at the same time, the surface of the board was still shaped using an inorganic binder.

[0145] The composite material prepared in this comparative example has a thermal conductivity of 0.031 W / (m·K), a compressive strength attenuation rate of <12% after low-temperature treatment (≤-18℃), a thickness change rate of 2.2% after 25 freeze-thaw cycles, a thermal conductivity retention rate of 87% after 25 freeze-thaw cycles, and slight shrinkage and collapse at the edges.

[0146] Comparative Example 4 In this comparative example, the conditions were the same as in Example 1, except that the atmospheric pressure staged drying was replaced with a single-stage rapid temperature rise drying. That is, after completing the hydrophobic modification and solvent replacement, the product was directly dried at 80 °C for 4 h, and then dried at 120 °C for 6 h, without setting the low-temperature pre-drying stage at 40 °C and the medium-temperature slow release stage at 60 °C.

[0147] The composite material prepared in this comparative example has a thermal conductivity of 0.038 W / (m·K), a static water contact angle of 145°, a compressive strength attenuation rate of <13% after low-temperature treatment (≤-18 ℃), a thickness change rate of 2.9% after 25 freeze-thaw cycles, and a thermal conductivity retention rate of 83% after 25 freeze-thaw cycles.

[0148] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a glass fiber reinforced SiO2 aerogel composite fireproof material, characterized in that, Includes the following steps: (1) Preparation of silicon source sol: Mix organosilicon source and / or inorganic silicon source, solvent, water, catalyst and functional filler to obtain precursor sol; (2) Pretreatment of glass fiber reinforced skeleton: The glass fiber reinforced skeleton is subjected to impurity removal, activation, wetting and / or surface coupling treatment; (3) Impregnation and composite: The pretreated glass fiber reinforced skeleton is impregnated in the precursor sol; (4) Gelation and aging treatment: The impregnated composite system is gelled and then aged in an oven. (5) Solvent exchange and hydrophobic modification: The wet gel is subjected to solvent exchange with organic solvent and surface hydrophobic treatment is performed using hydrophobic modifier; (6) Atmospheric pressure staged drying treatment: The modified composite wet gel is dried in stages under atmospheric pressure. The atmospheric pressure staged drying treatment includes a low temperature pre-drying stage, a medium temperature slow-release stage and a higher temperature enhanced drying stage; wherein, the temperature of the low temperature pre-drying stage is 35-40℃, the temperature of the medium temperature slow-release stage is 50-60℃, and the temperature of the higher temperature enhanced drying stage is 70-120℃. (7) Post-processing molding: The dried composite material is cut, pressed to a certain thickness, coated and laminated, edge treated or rolled up to obtain a plate-type or felt-type composite fireproof material.

2. The preparation method according to claim 1, characterized in that, The step of preparing the silicon source sol further includes: adding one or more organosilicon sources, anhydrous ethanol, and deionized water to a reaction vessel, stirring until homogeneous, adjusting the pH with hydrochloric acid, and then hydrolyzing with magnetic stirring to obtain an organosilicon source pre-hydrolyzed solution; and / or, One or more inorganic silicon sources are diluted with deionized water and acidified using a hydrochloric acid-activated cation exchange resin column to obtain an inorganic silicon source hydrolysate. Use organosilicon source pre-hydrolyzed solution and / or inorganic silicon source hydrolyzed solution as precursor sol.

3. The preparation method according to claim 1, characterized in that, Also includes: An anti-shrinkage additive is added to the system prior to step (4). The anti-shrinkage additive is selected from one or more of the following: silica powder, fumed silica, micron-sized silica particles, inorganic nanoparticles, and ceramic powder.

4. The preparation method according to claim 1, characterized in that, In step (1), the organosilicon source is selected from one or more of tetraethyl orthosilicate, methyltriethoxysilane, and methyltrimethoxysilane, and the inorganic silicon source is selected from one or more of water glass and silica sol. In step (2), the glass fiber reinforced skeleton is selected from one or more of glass fiber mat, ultrafine glass fiber mat, glass fiber paper, glass fiber cloth, and glass fiber needle-punched mat.

5. The preparation method according to claim 1, characterized in that, In step (5), the hydrophobic modifier is selected from one or more of trimethylchlorosilane, hexamethyldisilazane, methyltriethoxysilane, methyltrimethoxysilane, and silane coupling agents.

6. The preparation method according to claim 1, characterized in that, When the prepared composite fireproof material is a plate type, the preparation method further includes: applying an inorganic adhesive to the surface, edges and / or interlayer of the composite after step (5), and performing light pressing and / or coating composite treatment, wherein the inorganic adhesive includes silica sol.

7. A glass fiber reinforced SiO2 aerogel composite fireproof material, characterized in that, The composite fireproof material is prepared by the preparation method according to any one of claims 1 to 6, comprising a SiO2 aerogel phase and a glass fiber reinforced skeleton, wherein the mass ratio of the SiO2 aerogel phase to the glass fiber reinforced skeleton is 10:90 to 60:40, and the composite fireproof material is a plate-type or felt-type composite structure composed of the SiO2 aerogel phase and the glass fiber reinforced skeleton.

8. The composite fireproof material according to claim 6, characterized in that, The composite fireproof material also includes an anti-shrinkage additive, which is dispersed in the SiO2 aerogel phase and / or distributed in the interface region between the SiO2 aerogel phase and the glass fiber reinforced skeleton.

9. The composite fireproof material according to claim 1, characterized in that, The composite fire-retardant material has a thermal conductivity of 0.018~0.046 W / (m·K) at room temperature, and / or, according to claim 1, the composite fire-retardant material has a thermal conductivity of 0.018~0.046 W / (m·K) at room temperature, and / or, The static water contact angle of the composite fireproof material is 120-155°, and / or, The composite fireproof material has a 24-hour water absorption rate of no more than 4 wt%, and / or, After being treated at a low temperature of -18°C or less, the composite fireproof material exhibits a compressive strength reduction rate of no more than 10%, and / or, The thickness change rate of the composite fireproof material after 25 freeze-thaw cycles is no greater than 2.5%, and the thermal conductivity retention rate of the composite fireproof material after 25 freeze-thaw cycles is no less than 85%; and / or, The apparent density of the composite fire-retardant material is 80-220 kg / m³. 3 .

10. The composite fireproof material according to claim 1, characterized in that, The composite fireproof material also includes one or more of the following: surface protective layer, vapor barrier layer, protective layer, decorative layer, and adhesive fixing layer.

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