Preparation method of phenolic aldehyde coated silicon oxide aerogel plate

Abstract

The invention relates to a preparation method of a phenolic aldehyde coated silicon oxide aerogel plate, which comprises the following steps: preparing phenolic aldehyde reticular aerogel from resorcinol, formaldehyde, an organic solvent, 3-aminopropyltriethoxysilane and a columnar array template, and compounding the phenolic aldehyde reticular aerogel as a base material with silicon oxide aerogel. The silicon oxide aerogel is coated with phenolic aldehyde, so that the problem that the mechanical property of the silicon oxide aerogel is insufficient is solved. And compared with the traditional fibrofelt-reinforced silicon oxide aerogel, the phenolic aldehyde-coated silicon oxide aerogel has lower heat conduction familiarity and more excellent heat preservation and heat insulation effects. Wide application prospects are realized in the fields of building heat insulation, new energy automobile battery heat protection and the like.

Description

Technical Field

[0001] This invention belongs to the field of aerogel material preparation, specifically relating to a method for preparing phenolic resin-coated silica aerogel plates. Background Technology

[0002] Aerogels, as novel lightweight nanoporous materials, possess numerous advantages such as low density, high porosity, low thermal conductivity, and high adsorption capacity, showing broad application prospects in aerospace, building insulation, environmental remediation, and other fields. Among them, silica aerogels have attracted considerable attention due to their excellent performance; however, their high brittleness and poor mechanical properties severely limit their application range. To improve the mechanical properties of silica aerogels, researchers have attempted to composite them with other materials, such as phenolic resins. Phenolic resins are synthetic resins with good mechanical properties, thermal stability, and fire resistance. However, traditional aerogel / fiber felt composites suffer from high thermal conductivity and require additional flame-retardant treatment of the fiber felt substrate, increasing preparation costs and process complexity. Therefore, developing a composite material preparation method that can improve the mechanical properties of silica aerogels while optimizing thermal insulation and fire resistance is of significant practical importance. Summary of the Invention

[0003] In view of one or more of the above-mentioned defects or improvement needs of the prior art, the present invention aims to provide a method for preparing phenolic coated silica aerogel board. The composite material prepared by this method can overcome the problem of insufficient mechanical properties of silica aerogel, while having a lower thermal conductivity and better fire safety performance.

[0004] The specific technical solution is as follows: This invention provides a method for preparing a phenolic resin-coated silica aerogel plate, comprising the following steps: S1. Resorcinol, formaldehyde, organic solvent and 3-aminopropyltriethoxysilane are respectively put into a container and mixed evenly. After stirring evenly, a phenolic aerogel precursor solution is obtained. S2. Pour the phenolic aerogel precursor solution obtained in step S1 into the columnar array template, and let it stand to solidify to form a phenolic network structure gel. S3. Demold the phenolic network gel after standing in step S2. After demolding, soak it in an ammonia solution. During the soaking process, the phenolic network gel will be corroded by the ammonia solution, which can effectively increase the roughness of the surface of the phenolic network structure gel, thereby improving the bonding strength of the silica aerogel in the mesh and preventing the silica aerogel from falling off the mesh after composite. S4. The phenolic network gel soaked in step S3 is aged and dried to obtain a network phenolic aerogel. The role of aging is to strengthen the gel skeleton structure and improve its strength and toughness by promoting further condensation and cross-linking of unreacted groups inside the gel, while optimizing the pore distribution, thereby ensuring the performance of the aerogel. The role of drying is to remove the solvent from the gel, thereby preserving the three-dimensional porous network structure of the aerogel and ensuring that it has high porosity to achieve the special properties of aerogel materials. S5. Add silicon source, organic solvent, water and catalyst into a container and mix evenly. Stir evenly at room temperature to obtain silica aerogel precursor solution. S6. Pour the silica aerogel precursor solution obtained in step S5 into the network phenolic aerogel obtained in step S4. After gel formation, age and dry the solution to obtain a phenolic-coated silica aerogel plate. As a preferred technical solution, in step S1, the amounts of resorcinol, formaldehyde, organic solvent, and 3-aminopropyltriethoxysilane are added in a molar mass ratio of 1:1 to 3:1 to 4:1 to 2; and the stirring time is 3 to 30 minutes.

[0005] As a preferred technical solution, the organic solvent in step S1 is one of ethanol, methanol or acetone.

[0006] As a preferred technical solution, the depth of the columnar array template in step S2 is 0.5mm to 5mm.

[0007] As a preferred technical solution, the mass ratio of ammonia to water in the ammonia solution in step S3 is 1:10; Soaking time is 1 to 5 minutes.

[0008] As a preferred technical solution, the drying in step S4 is one of atmospheric pressure drying, vacuum drying, and supercritical drying.

[0009] As a preferred technical solution, the mass ratio of silicon source, organic solvent, water and catalyst in step S5 is 1:12-36:2.5:0.01-0.05; The stirring time is 10 to 15 minutes.

[0010] As a preferred technical solution, the silicon source in step S5 is one of methyl orthosilicate or ethyl orthosilicate, the organic solvent is one of ethanol, methanol or acetone, and the catalyst is one or more of ammonium fluoride and ammonia.

[0011] As a preferred technical solution, the phenolic coated silica aerogel board is a phenolic coated silica aerogel board prepared by a method according to any one of claims 1-8. The aerogel board is composed of phenolic aerogel coated with silica aerogel and has excellent mechanical properties, low thermal conductivity and flame retardant properties.

[0012] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include: Compared to traditional pure silica aerogel, phenolic aerogel exhibits superior mechanical properties. Coating with phenolic aerogel significantly enhances the overall mechanical strength and toughness of the aerogel composite material, making it more robust and durable, effectively overcoming the relative fragility of pure silica aerogel. Furthermore, phenolic aerogel has a lower thermal conductivity than commonly used fiber felt substrates. Therefore, phenolic-coated silica aerogel composites offer significantly better thermal insulation performance compared to the current mainstream aerogel / fiber felt composites. Simultaneously, the inherent flame-retardant properties of phenolic resin reduce or even eliminate the need for additional flame-retardant treatment of the fiber felt substrate during preparation, resulting in superior fire safety performance in the final product. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the columnar array template of the present invention. Figure 2 This is a photograph of the phenolic-coated silica aerogel of the present invention. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0016] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0017] This invention provides a specific technical solution: a method for preparing a phenolic resin-coated silica aerogel plate, the specific steps of which are as follows: S1. At a certain temperature, resorcinol, formaldehyde, organic solvent, and 3-aminopropyltriethoxysilane are added into a container in a certain molar mass ratio and mixed evenly. After stirring for a certain time, a phenolic aerogel precursor solution is obtained. S2. Pour the phenolic aerogel precursor solution obtained in step S1 into the columnar array template, and let it stand for a period of time to form a phenolic network structure gel. S3. Demold the phenolic network gel that has been left to stand in step S2, and then soak it in an ammonia solution. S4. The phenolic network gel soaked in step S3 is aged and dried to obtain a network phenolic aerogel. S5. Add silicon source, organic solvent, water and catalyst into a container in a certain mass ratio and mix evenly. After stirring at room temperature for a certain period of time, a silica aerogel precursor solution is obtained. S6. Pour the silica aerogel precursor solution obtained in step S5 into the network phenolic aerogel obtained in step S4. After the gel is formed, age and dry it to obtain a phenolic coated silica aerogel plate.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. A method for preparing a phenolic resin-coated silica aerogel plate includes the following specific steps: Example 1 At room temperature, resorcinol, formaldehyde, alcohol, and 3-aminopropyltriethoxysilane were mixed in a molar ratio of 1:2:2.5:2 and stirred for 30 min. The mixture was then poured into a 3 mm deep columnar array template. After gel formation, the template was demolded and immersed in an ammonia solution for 5 min. The immersed phenolic network wet gel was then aged and supercritically dried to obtain a phenolic network aerogel. Tetraethyl orthosilicate, ethanol, water, ammonia, and ammonium fluoride were mixed in a mass ratio of 1:33.5:2.5:0.03:0.01 and stirred for 15 min. The mixture was then poured into the phenolic network aerogel. After gel formation, the mixture was aged and supercritically dried to obtain a phenolic-coated silica aerogel plate.

[0019] The phenolic resin coated silica aerogel board has a good appearance, a thermal conductivity of 0.0149 W / (m·k), and a UL 94 flame retardant rating of V-0.

[0020] Example 2 At room temperature, resorcinol, formaldehyde, alcohol, and 3-aminopropyltriethoxysilane were mixed in a molar ratio of 1:2:3:2 and stirred for 30 min. The mixture was then poured into a 5 mm deep columnar array template. After gel formation, the template was demolded and immersed in an ammonia solution for 5 min. The immersed phenolic network wet gel was then aged and vacuum dried to obtain a phenolic network aerogel. Tetraethyl orthosilicate, ethanol, water, ammonia, and ammonium fluoride were mixed in a mass ratio of 1:15.5:2.5:0.01:0.01 and stirred for 10 min. The mixture was then poured into the phenolic network aerogel. After gel formation, the mixture was aged and supercritically dried to obtain a phenolic-coated silica aerogel plate.

[0021] The phenolic resin coated silica aerogel board has a good appearance, a thermal conductivity of 0.0214 W / (m·k), and a UL 94 flame retardant rating of V-0.

[0022] Example 3 At room temperature, resorcinol, formaldehyde, alcohol, and 3-aminopropyltriethoxysilane were mixed in a molar ratio of 1:2:3:2 and stirred for 30 min. The mixture was then poured into a 3 mm deep columnar array template. After gel formation, the template was demolded and immersed in an ammonia solution for 5 min. The immersed phenolic network wet gel was then aged and supercritically dried to obtain a phenolic network aerogel. Tetraethyl orthosilicate, ethanol, water, ammonia, and ammonium fluoride were mixed in a mass ratio of 1:15.5:2.5:0.01:0.01 and stirred for 15 min. The mixture was then poured into the phenolic network aerogel. After gel formation, the mixture was aged and supercritically dried to obtain a phenolic-coated silica aerogel plate.

[0023] The phenolic resin coated silica aerogel board has a good appearance, a thermal conductivity of 0.0242 W / (m·k), and a UL 94 flame retardant rating of V-0.

[0024] Example 4 At room temperature, resorcinol, formaldehyde, alcohol, and 3-aminopropyltriethoxysilane were mixed in a molar ratio of 1:2:2.5:2 and stirred for 30 min. The mixture was then poured into a 3 mm deep columnar array template. After gel formation, the template was demolded and immersed in an ammonia solution for 5 min. The immersed phenolic network wet gel was then aged and supercritically dried to obtain a phenolic network aerogel. Tetraethyl orthosilicate, ethanol, water, ammonia, and ammonium fluoride were mixed in a mass ratio of 1:21.5:2.5:0.02:0.01 and stirred for 15 min. The mixture was then poured into the phenolic network aerogel. After gel formation, the mixture was aged and supercritically dried to obtain a phenolic-coated silica aerogel plate.

[0025] The phenolic resin coated silica aerogel board has a good appearance, a thermal conductivity of 0.0169 W / (m·k), and a UL 94 flame retardant rating of V-0.

[0026] In summary, compared to traditional pure silica aerogel, the phenolic aerogel of this invention exhibits superior mechanical properties. Coating with phenolic aerogel significantly enhances the overall mechanical strength and toughness of the aerogel composite material, making it more robust and durable, effectively overcoming the relative fragility of pure silica aerogel. Furthermore, phenolic aerogel has a lower thermal conductivity than commonly used fiber felt substrates. Therefore, the phenolic-coated silica aerogel composite material has a more significant advantage in thermal insulation performance compared to the currently mainstream "aerogel / fiber felt" composite materials. Simultaneously, the inherent flame-retardant properties of phenolic resin can reduce or even eliminate the need for additional flame-retardant treatment of the fiber felt substrate during the preparation process, and can impart superior fire safety performance to the final product.

[0027] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a phenolic resin-coated silica aerogel plate, characterized in that, The specific steps are as follows: S1. Resorcinol, formaldehyde, organic solvent and 3-aminopropyltriethoxysilane are respectively put into a container and mixed evenly. After stirring evenly, a phenolic aerogel precursor solution is obtained. S2. Pour the phenolic aerogel precursor solution obtained in step S1 into the columnar array template, and let it stand to solidify to form a phenolic network structure gel. S3. Demold the phenolic network gel that has been left to stand in step S2, and then soak it in an ammonia solution. S4. The phenolic network gel soaked in step S3 is aged and dried to obtain a network phenolic aerogel. S5. Add silicon source, organic solvent, water and catalyst into a container and mix evenly. Stir evenly at room temperature to obtain silica aerogel precursor solution. S6. Pour the silica aerogel precursor solution obtained in step S5 into the network phenolic aerogel obtained in step S4. After the gel is formed, age and dry it to obtain a phenolic coated silica aerogel plate.

2. The method for preparing a phenolic resin-coated silica aerogel plate according to claim 1, characterized in that: In step S1, resorcinol, formaldehyde, organic solvent, and 3-aminopropyltriethoxysilane are added in a molar mass ratio of 1:1-3:1-4:1-2. The stirring time is 3 to 30 minutes.

3. The method for preparing a phenolic resin-coated silica aerogel plate according to claim 1, characterized in that: The organic solvent mentioned in step S1 is one of ethanol, methanol or acetone.

4. The method for preparing a phenolic resin-coated silica aerogel plate according to claim 1, characterized in that: The depth of the columnar array template mentioned in step S2 is 0.5mm to 5mm.

5. The method for preparing a phenolic resin-coated silica aerogel plate according to claim 1, characterized in that: In step S3, the mass ratio of ammonia to water in the ammonia solution is 1:

10. Soaking time is 1 to 5 minutes.

6. The method for preparing a phenolic resin-coated silica aerogel plate according to claim 1, characterized in that: The drying process described in step S4 is one of atmospheric pressure drying, vacuum drying, or supercritical drying.

7. The method for preparing a phenolic resin-coated silica aerogel plate according to claim 1, characterized in that: In step S5, the mass ratio of the silicon source, organic solvent, water, and catalyst is 1:12-36:2.5:0.01-0.

05. The stirring time is 10 to 15 minutes.

8. The method for preparing a phenolic resin-coated silica aerogel plate according to claim 1, characterized in that: The silicon source in step S5 is one of methyl orthosilicate or tetraethyl orthosilicate; the organic solvent is one of ethanol, methanol, or acetone; and the catalyst is one or more of ammonium fluoride and ammonia.

9. A phenolic resin-coated silica aerogel board, characterized in that: The phenolic coated silica aerogel board is a phenolic coated silica aerogel board prepared by a method according to any one of claims 1-8.

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