Preparation method of high-performance aerogel thermal insulation material

Abstract

The invention discloses a preparation method of a high-performance aerogel thermal insulation material, which comprises the following steps: A, taking glass fiber as a substrate of the aerogel thermal insulation material, and loading silicon dioxide aerogel on the substrate; b, preparing aerogel silicon dioxide by taking organosilane as a raw material through the working procedures of base material preparation, glue preparation, glue dipping, gel aging, wet gel preparation, hydrophobic modification and supercritical drying; according to the base material preparation, a glass fiber base material and an auxiliary material are alternately and neatly stacked, the auxiliary material is a non-woven fabric or a PP film of the corresponding size, the stacking number is accurately controlled according to the product thickness, and the volume density of the glass fiber base material is 0.09-0.2 g / cm < 3 >. The glass fiber used in the invention is used as a reinforcing matrix, provides a large specific surface area, provides enough uniformly distributed adsorption sites for the aerogel, and provides excellent mechanical properties for the aerogel, the used silicon source does not generate extra substances in the reaction process, and alcohol generated by hydrolysis is used as a solvent and can be recycled.

Description

Technical Field

[0001] The invention relates to the technical field of functional composite materials, in particular to a method for preparing a high-performance aerogel thermal insulation material. Background Art

[0002] Improving energy utilization and reducing energy loss are particularly important for energy conservation. Therefore, high-performance thermal insulation materials are receiving more and more attention and are widely used in energy storage, power batteries, construction, aviation, aerospace and other fields.

[0003] SiO 2 Aerogel is a new type of material with a three-dimensional network structure. It has many excellent properties, such as ultra-high specific surface area, large porosity, ultra-low density, low thermal conductivity and low refractive index. Based on these characteristics, SiO 2 Aerogel is considered an ideal high-performance thermal insulation material.

[0004] But since pure SiO 2 Aerogels have defects such as easy hygroscopicity and poor mechanical properties, which makes them difficult to be used alone in practical engineering. 2 Aerogel is used as a thermal insulation material. The mechanical properties and performance of aerogel materials are improved by fiber composite. 2 Aerogel has great application prospects in the field of thermal insulation due to its excellent mechanical properties and thermal insulation properties.

[0005] Fiber reinforced SiO 2 Aerogel thermal insulation materials are mostly prepared by the sol-gel method, using silane as the raw material. Under the action of a catalyst, wet gel products are synthesized through hydrolysis and polycondensation reactions. After modification and drying, functional treatment and solvent extraction are performed to finally obtain the finished product. Due to the diversity of product usage scenarios, fiber-reinforced SiO 2 Aerogel insulation materials are often required to have differences in size, density, insulation and other properties. The regulation of these differences in the industry is mostly based on the raw material ratio and glass fiber substrate, which invisibly increases the difficulty of preparation. For this reason, we propose a preparation method for high-performance aerogel insulation materials. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing a high-performance aerogel thermal insulation material to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing a high-performance aerogel thermal insulation material, comprising the following steps:

[0008] A. Aerogel insulation material uses glass fiber as the substrate and loads silica aerogel on the substrate;

[0009] B. The aerogel silica is prepared from organosilane through the processes of substrate preparation, glue mixing, dipping, gel aging, wet gel preparation, hydrophobic modification, and supercritical drying.

[0010] Preferably, for the substrate preparation, the glass fiber substrate and auxiliary materials are stacked neatly in an alternating manner. The auxiliary materials are non-woven fabrics or PP films of corresponding sizes, and the stacking quantity is precisely controlled according to the product thickness. The bulk density of the glass fiber substrate is 0.09 g / cm 3 ~0.2 g / cm 3 , and the thickness of the glass fiber substrate is 0.8 - 10 mm.

[0011] Preferably, the sol is prepared by using organosilane as the raw material for aerogel silica, high-purity alcohol as the solvent, adding water and a catalyst, and configuring a certain density by the one-pot method. The organosilane is selected from one or a combination of silicon 28, silicon 32, or silicon 40. The concentration of high-purity alcohol is 90% - 100%. The catalysts are ammonia water and ammonium fluoride. The density of the prepared glue is 0.01 g / cm 3 ~0.3 g / cm 3 , the temperature of the sol is 15℃ - 25℃, the mixing and stirring time of the sol is 5 min - 15 min, and the starting gel time of the sol is 0.5 h - 3 h.

[0012] Preferably, for the dipping process, the glass fiber reinforced substrate is completely immersed in the prepared sol. The dipping process uses non-standard tooling and is completed in a non-standard dipping tank. The non-standard tooling can achieve effective impregnation between the substrate and the sol and the regulation of the finished product performance. The dipping time is half of the gel time. The finished product performance mainly includes thickness, density, thermal conductivity, and high-temperature heat insulation. The regulation of the dipping section takes the regulation of thickness and density as the initial goal.

[0013] Preferably, the gel aging is the process from sol to gel, which includes hydrolysis reaction and polycondensation reaction. The aging temperature is 10℃ - 60℃, and the aging time is 6 - 48 h.

[0014] Preferably, for the wet gel preparation, the wet gel products and auxiliary materials are stacked alternately in a drying basket. The auxiliary materials include one or a combination of non-woven fabrics, 3D cotton, drying baskets, white dense mesh, or polyester mesh.

[0015] Preferably, a hydrophobic modifier is required during the hydrophobic modification process. The hydrophobic modifier is a silane containing methyl. The hydrophobic modification temperature is 20℃ - 60℃, and the hydrophobic modification time is 12 h - 60 h.

[0016] Preferably, the supercritical medium in the critical drying is carbon dioxide, and the supercritical temperature and pressure are higher than the temperature and pressure required for carbon dioxide to reach the supercritical state. The temperature is 40-70 °C, the pressure is 10-14 Mpa, and the drying time is 3h-10h.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] (1) The glass fiber used in the present invention serves as a reinforcing matrix, providing a large specific surface area, sufficient and evenly distributed adsorption sites for the aerogel, and excellent mechanical properties for the aerogel;

[0019] (2) The silicon source used in the present invention generates no additional substances during the reaction. The alcohol generated by hydrolysis can be recycled as a solvent. The hydrophobic modification reagent is methylsilane-containing, and there is also no substitution of other elements and generation of additional substances, realizing environmental friendliness in the whole process and the green environmental protection attribute of the product;

[0020] (3) The high-performance aerogel thermal insulation material of the present invention can be customized for properties such as thickness, density, thermal conductivity, and high-temperature heat insulation according to the needs of product customers, avoiding over-performance and achieving cost control;

[0021] (4) On the basis of regulating the product performance by the aerogel density, the present invention proposes to regulate the performance of the thermal insulation material by adjusting the thickness of the base material, avoiding the increase in the aerogel density caused by being limited by the base material density, and at the same time giving the adjustment direction for the mechanical properties of the product. Detailed implementation mode

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0023] In the first aspect of the present invention, a preparation of a high-performance aerogel thermal insulation material is provided, wherein the high-performance aerogel thermal insulation material includes a reinforced fiber matrix and a silica aerogel.

[0024] In the present invention, the glass-reinforced fiber matrix is a glass fiber material, and its bulk density is 0.09 g / cm 3 ~0.2 g / cm 3, the thickness of the glass fiber substrate is 0.8 - 20 mm. If the bulk density is too high, it is likely to cause the density of the aerogel thermal insulation material to be too large, the thermal conductivity to be too high, and the thermal insulation performance to be poor; if the bulk density is too low, it is likely to cause the density of the aerogel thermal insulation material to be too small, the thermal conductivity to be too high, and the adhesion of the aerogel to decrease. If the glass fiber substrate is too thin or too thick, it will also cause loss of the mechanical properties or thermal insulation performance of the product.

[0025] In the present invention, the silica aerogel is prepared from organosilane and water as raw materials, high-purity alcohol as a solvent, and ammonia water and ammonium fluoride as catalysts. Among them, the organosilane has a silica content of 20% - 50%, and the high-purity alcohol is 90% - 100%. After the solution is mixed into a sol, the organosilane hydrolyzes with water and then undergoes self-condensation under the action of the catalyst to form a gel. The high-purity alcohol is used as a solvent to adjust the density of silica inside the sol and solidify the aerogel skeleton. The density of silica is 0.01 g / cm 3 ~0.3 g / cm 3 , if the silica content is too high, it is likely to cause the thermal insulation performance of the prepared material to decline; if the silica content is too low, it may cause the mechanical strength to decline.

[0026] In the present invention, the preparation method of the high-performance aerogel thermal insulation material is as follows:

[0027] Substrate preparation: The glass fiber substrate and auxiliary materials are stacked neatly alternately. The auxiliary materials are non-woven fabrics or PP films of corresponding sizes. The auxiliary materials exist for the purpose of facilitating the separation of the product in the subsequent wet gel preparation section. Without the auxiliary materials, it will be impossible to achieve lossless separation for wet gel products of a certain density;

[0028] Mixing glue: That is, the preparation of the sol. The specific method refers to Example 1. Among them, the sol temperature is 15°C - 25°C, the mixing and stirring time of the sol is 5 min - 15 min, and the starting gel time of the sol is 0.5 h - 3 h. The sol temperature, stirring time, and gel time should not be too high or too low, which is likely to cause abnormal gel phenomena of the product;

[0029] Impregnating glue: Inject the prepared sol into the impregnating glue pool, and completely immerse the glass fiber sheet and auxiliary materials that have completed the substrate preparation in the prepared sol in multiple batches according to a fixed quantity. The impregnating glue completion time is less than half of the gel time. If the time is too long, it will cause the prepared product to be unable to complete the impregnation or the viscosity of the sol glue to be too high to be effectively impregnated into the substrate;

[0030] Gel aging: For the product after impregnating glue, it is placed and treated in a sealed and constant temperature manner. Gel aging refers to the process from sol to gel, which includes hydrolysis reaction and polycondensation reaction. The aging temperature is 10°C - 60°C, and the aging time is 6 - 48 h. If the temperature and time are outside the range, it will affect the gel strength and effect of the product;

[0031] Wet gel preparation: The aged products are separated layer by layer using auxiliary materials, and then the wet gel products and the auxiliary materials are alternately stacked in a drying basket. The auxiliary materials are one or more of non-woven fabric, 3D cotton, drying basket, white mesh, and polyester mesh. The role of the auxiliary materials in this process is to provide a space for the modified liquid and the drying medium to flow between the wet gel product layers;

[0032] Hydrophobic modification: The hydrophobic modifier is a silane containing methyl. The hydrophobic modification temperature is 20°C to 60°C, and the hydrophobic modification time is 12h to 60h. The principle of hydrophobic modification is that the silane containing methyl reacts chemically with the terminal hydroxyl groups inside the wet gel, so that there are a large number of methyl groups at the material terminals, achieving the purpose of hydrophobicity;

[0033] Supercritical drying: The supercritical medium is carbon dioxide. The supercritical temperature and pressure are higher than the temperature and pressure required for carbon dioxide to reach the supercritical state, with the temperature being 40°C to 70°C and the pressure being 10 Mpa to 16 Mpa. The drying time is 3h to 10h.

[0034] In the second aspect of the present invention, based on the above preparation method, the present invention also provides a method for regulating the performance of a high-performance aerogel thermal insulation material. The regulation method is as follows:

[0035] In the base material preparation process, the non-woven fabric used as the auxiliary material has a thickness of 0.2 mm, the center value of the glass fiber base material thickness is a, and the bulk density is ρ 1 , and the glass fiber base material and the non-woven fabric of the corresponding size are alternately stacked neatly, with a fixed quantity of n.

[0036] In the glue preparation process, the density of silicon dioxide in the sol is ρ 2 .

[0037] In the impregnation process, the height limit of the impregnated stack of n products is restricted, that is, limited impregnation, with the limit height being h, the center value of the thickness of the dried finished product being b, and the bulk density being ρ.

[0038] Thickness of the dried finished product: b = [h - 0.2(n + 1)] / n;

[0039] The density of the dried finished product comes from two aspects. On the one hand, it comes from the density supply of the base material. On the basis of the base material supply, the aerogel filling serves as the density supply on the other hand. Therefore, the density formula of the finished aerogel thermal insulation material is as follows:

[0040] ρ = ρ 1 *c / a + ρ 2 *b / a = ρ 1 {[h - 0.2(n + 1)] / n - 0.2} / a + ρ 2 {h - 0.2(n + 1)] / n}a;

[0041] In the above formula, the substrate thickness a and density ρ are known. 1 , glue density ρ 2 By adjusting the limit height h and the number of limit products n, the thickness and density of the finished product can be adjusted and confirmed. Furthermore, the thermal conductivity and thermal insulation performance of the finished product have a certain adjustment space according to the density change.

[0042] Example

[0043] The present invention will be further described below in the form of examples. However, these examples are only illustrative of the preferred embodiments of the present invention, and the protection scope of the present invention should not be construed as being limited to these examples.

[0044] The silane used in the examples was provided by Jiangxi Chenguang New Materials Co., Ltd., other reagents were from the Beijing Branch of Sinopharm Reagent Company, and the fiber material was from Jiangsu Dali Energy Saving Technology Co., Ltd.

[0045] Example 1

[0046] Stack glass fibers with a thickness of 2.5±0.2mm and a volume density of 0.1 alternately with non-woven fabrics of corresponding long sizes, with a total stack height of 43cm. Select a sol formula density of 0.12g / cm 3 : Add 223.7g of 97% high-purity alcohol, 100g of organosilane with a silica content of 40%, and 17.9g of deionized water to the container in sequence, mix well, then add ammonium fluoride and ammonia solution as catalysts to the container, stir well to form a sol, enlarge the prepared sol in the same proportion, the obtained sol temperature is 19°C, mix and stir for 5 minutes, and the gel time is controlled at 2.5h. In half of the gel time, the neatly stacked substrates are completely immersed in the prepared sol in a fixed number of times. After the dipping is completed, the dipping pool is sealed and placed at a constant temperature. The aging time is 12h and the aging temperature is 25°C. After the gel is completed, the auxiliary non-woven fabric used in the substrate preparation is used to separate the gel product layer by layer, and then the wet gel product and the auxiliary materials are alternately prepared layer by layer in the drying tooling, and the drying tooling containing the wet gel product is placed in a modification container, and methyl-containing silane is added into the container as a modifier according to a certain concentration ratio for hydrophobic modification. If necessary, a certain amount of catalyst is added to promote the modification efficiency. The modification temperature is set at 45°C and the modification time is 40h. Subsequently, the product is placed in a supercritical reactor with a drying medium of carbon dioxide, and the temperature is set at 65°C and the pressure is 14Mpa, and the product is dried for 6h.

[0047] Except for the contents shown in Table 1 and the notes, Examples 2 to 6 were carried out in the same manner as Example 1.

[0048] Table 1. Process conditions and material properties used in each example

[0049]

[0050] Example 7

[0051] Stack glass fibers with a thickness of 2.5±0.2mm and a volume density of 0.1 alternately with non-woven fabrics of corresponding long sizes, with a total stack quantity of 125 pieces. Select a sol formula density of 0.12g / cm 3 : Add 223.7g of 97% high-purity alcohol, 100g of organosilane with a silica content of 40%, and 17.9g of deionized water to the container in sequence, mix well, then add ammonium fluoride and ammonia solution as catalysts to the container, stir well to form a sol, enlarge the prepared sol in the same proportion, the obtained sol temperature is 19°C, mix and stir for 5 minutes, and the gel time is controlled at 2.5h. In half of the gel time, the neatly stacked substrates are completely immersed in the prepared sol in a fixed number of times, and the height of the entire stack of dipped glue is limited to a total height of 385mm. After the dip is completed, the dip pool is sealed and placed at a constant temperature for aging time of 1 2h, age the gel at an aging temperature of 25℃. After the gel is completed, use the auxiliary non-woven fabric used in the substrate preparation to separate the completed gel product layer by layer, and then alternately prepare the wet gel product and the auxiliary materials layer by layer into the drying tooling, put the drying tooling containing the wet gel product into a modification container, and add methyl-containing silane as a modifier into the container according to a certain concentration ratio for hydrophobic modification. If necessary, add a certain amount of catalyst to promote the modification efficiency. The modification temperature is set at 45℃ and the modification time is 40h. Subsequently, the product is placed in a supercritical reactor with a drying medium of carbon dioxide. The temperature is set at 65℃ and the pressure is 14Mpa, and the product is dried for 6h.

[0052] Except for the contents shown in Table 2 and the notes, Examples 8 and 9 were carried out in the same manner as Example 7.

[0053] Table 2. Process conditions and material properties of the limited dipping embodiment

[0054]

[0055] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-performance aerogel thermal insulation material, characterized in that: The following steps are involved: A. Aerogel insulation material uses glass fiber as the substrate and loads silica aerogel on the substrate; B. Aerogel silica is prepared from organosilane through the processes of substrate preparation, glue preparation, glue dipping, gel aging, wet gel preparation, hydrophobic modification, and supercritical drying.

2. The method for preparing a high-performance aerogel thermal insulation material according to claim 1, characterized in that: The substrate material is prepared by stacking glass fiber substrate and auxiliary materials alternately and neatly. The auxiliary materials are non-woven fabrics or PP films of corresponding sizes. The stacking quantity is precisely controlled according to the thickness of the product. The volume density of the glass fiber substrate is 0.05g / cm 3 ~0.5g / cm 3 , the thickness of the glass fiber substrate is 0.5mm~100mm.

3. The method for preparing a high-performance aerogel thermal insulation material according to claim 1, characterized in that: The sol is aerogel silica with organosilane as raw material, high-purity alcohol as solvent, water and catalyst added, and a certain density is configured in a one-pot method. The organosilane selects one or more combinations of silicon 28, silicon 32 or silicon 40, the concentration of high-purity alcohol is 75% to 100%, the catalyst is ammonia water and ammonium fluoride, the sol density is the theoretical silica density, the sol temperature is 10°C to 30°C, the sol mixing and stirring time is 2min to 30min, and the sol gelation start time is 0.5h to 3h.

4. The method for preparing a high-performance aerogel thermal insulation material according to claim 1, characterized in that: The dipping process is to completely immerse the glass fiber reinforced substrate in the prepared sol. The dipping process uses non-standard tooling, and the dipping process is completed in a non-standard dipping pool. The non-standard tooling can achieve effective impregnation between the substrate and the sol and regulation of the performance of the finished product. The dipping time is half of the gel time. The performance of the finished product is mainly based on thickness, density, thermal conductivity and high-temperature insulation. The regulation of the dipping section takes the regulation of thickness and density as the initial goal.

5. The method for preparing a high-performance aerogel thermal insulation material according to claim 1, characterized in that: The gel aging is a process from sol to gel, which includes hydrolysis reaction and polycondensation reaction. The aging temperature is 10° C. to 60° C. and the aging time is 6 to 48 hours.

6. The method for preparing a high-performance aerogel thermal insulation material according to claim 1, characterized in that: The wet gel preparation is to alternately stack the wet gel product and auxiliary materials in a drying basket, wherein the auxiliary materials include one or more combinations of non-woven fabrics, 3D cotton, drying baskets, white dense mesh or polyester mesh.

7. The method for preparing a high-performance aerogel thermal insulation material according to claim 1, characterized in that: A hydrophobic modifier is required in the hydrophobic modification process. The hydrophobic modifier is a methyl-containing silane. The hydrophobic modification temperature is 20° C. to 60° C., and the hydrophobic modification time is 12 h to 60 h.

8. The method for preparing a high-performance aerogel thermal insulation material according to claim 1, characterized in that: The supercritical medium in the critical drying is carbon dioxide, the supercritical temperature and pressure are higher than the temperature and pressure required for carbon dioxide to reach a supercritical state, the temperature is 40-70°C, the pressure is 10-14Mpa, and the drying time is 3h-10h.

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