A production process of environmentally friendly aerogel insulation pad

Abstract

The present invention relates to the field of material technology, and in particular to a production process for an environmentally friendly aerogel thermal insulation pad. The production process for an environmentally friendly aerogel thermal insulation pad provided by the present invention comprises the following steps: S1: adding fiber material to an aerogel composite material and then performing ultrasonic dispersion, and then adding additives and hydrophobic agents to react to obtain a sol-gel mixture; S2: curing, drying and hot-pressing the sol-gel mixture to obtain the environmentally friendly aerogel thermal insulation pad; wherein the hydrophobic agent is tannic acid, and the additive is nano-silica. The present invention adds hydrophobic agent tannic acid and additive nano-silica, and the two can synergistically improve the waterproof performance of the aerogel thermal insulation pad. And by hot-pressing the dried aerogel thermal insulation pad, the waterproof performance of the aerogel thermal insulation pad can be further improved.

Description

Technical Field

[0001] The invention relates to the technical field of materials, and in particular to a production process of an environmentally friendly aerogel thermal insulation pad. Background Art

[0002] Aerogel is a material with a nanoporous structure. It is a gel with a three-dimensional network structure formed by the mutual aggregation of colloidal particles or polymer molecules. After drying, most of the solvent is removed, and its network structure is retained. At the same time, the gas is filled in the pores to form an aerogel. Aerogel insulation pads are mats with thermal insulation functions made using this special structure of aerogel.

[0003] The thermal insulation performance of aerogel insulation pads is mainly based on their unique nanoporous structure. Its porosity is extremely high, reaching more than 90%, and these tiny pores limit the thermal conduction of gas molecules. The gas is in a relatively static state in the pores, and thermal conduction is mainly achieved through the collision of gas molecules. The extremely small size of the pores greatly reduces the collision frequency of gas molecules, thereby effectively reducing thermal conduction. At the same time, the solid skeleton structure of aerogel also has a low thermal conductivity, further enhancing its thermal insulation effect.

[0004] The waterproof performance of aerogel thermal insulation pads is mainly achieved by adding silane coupling agents such as KH-550, KH-560, etc. during the preparation process. They can react with the hydroxyl groups on the surface of the aerogel to reduce its surface energy, thereby improving the hydrophobicity of the aerogel. Alternatively, a high molecular polymer with waterproof properties, such as polymethyl methacrylate (PMMA) emulsion, is added during the preparation process, which can form a waterproof film on the surface of the aerogel. However, these additives will cause certain pollution to the environment. For this reason, it is urgent to develop a production process for environmentally friendly aerogel thermal insulation pads. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a production process of an environmentally friendly aerogel thermal insulation pad. By adding a hydrophobic agent tannic acid and an additive nano-silicon dioxide, the two can synergistically improve the waterproof performance of the aerogel thermal insulation pad.

[0006] To this end, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides, in an optional embodiment, a production process for an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0008] S1: adding fiber material to the aerogel composite material and then performing ultrasonic dispersion, and then adding additives and a hydrophobic agent to react to obtain a sol-gel mixture;

[0009] S2: curing, drying and hot pressing the sol-gel mixture to obtain the environmentally friendly aerogel thermal insulation pad;

[0010] Wherein, the hydrophobic agent is tannic acid, and the additive is nano silicon dioxide.

[0011] In the present invention, by adding the hydrophobic agent tannic acid and the additive nano-silica, the two can synergistically improve the waterproof performance of the aerogel insulation pad. There are a large number of hydroxyl groups on the surface of nano-silica, which has strong surface activity. These hydroxyl groups can react with some hydrophobic modifiers, such as reacting with substances such as silane coupling agents. The alkoxy group of the silane coupling agent will react with the hydroxyl groups on the surface of the nano-silica, and graft hydrophobic organic groups, such as alkyl groups, on its surface. When nano-silica exists in an aerogel system, the surface-modified nano-silica can reduce the affinity of the aerogel surface to water, thereby producing a hydrophobic effect. Tannic acid molecules contain a large number of polar groups such as phenolic hydroxyl groups, which can form hydrogen bonds with polymer chains in the aerogel and hydroxyl groups on the surface of nano-silica. In the aerogel system, tannic acid is interconnected with aerogel and nano-silica through hydrogen bonds to form a tight network structure. This network structure changes the surface properties of the aerogel and reduces the adsorption capacity of the aerogel surface to water. At the same time, non-polar structures such as benzene rings in tannic acid molecules form a hydrophobic area on the surface of the aerogel, thus giving the aerogel hydrophobic properties.

[0012] Preferably, the pressure of the hot pressing treatment is 15 MPa-20 MPa; and / or the temperature of the hot pressing treatment is 165-185° C., and the time is 30-50 min.

[0013] In the present invention, the waterproof performance of the aerogel thermal insulation pad can be further improved by hot pressing the dried aerogel thermal insulation pad. In addition, if the temperature of the hot pressing is too low, it may lead to poor bonding between the materials and fail to form a dense and uniform structure; if the temperature of the hot pressing is too high, the structure of the aerogel may be damaged, affecting its thermal insulation performance and other physical properties. If the pressure of the hot pressing is too small, a good compaction effect cannot be achieved, and the thermal insulation pad may have pores or defects, affecting its thermal insulation performance and mechanical properties; if the pressure of the hot pressing is too high, the aerogel material may be over-compressed, resulting in damage to its internal structure, which will also affect the performance of the thermal insulation pad.

[0014] Preferably, the mass ratio of the aerogel composite material, the fiber material, the additive and the hydrophobic agent is 1: (0.1-0.3): (0.03-0.08): (0.01-0.05). Furthermore, the mass ratio of the aerogel composite material, the fiber material, the additive and the hydrophobic agent is 1: 0.2: 0.05: 0.04.

[0015] Preferably, in step S1, the reaction time is 1-3 hours; and / or the reaction is carried out under stirring. The fiber material is selected from one or more of glass fiber, ceramic fiber, carbon fiber or plant fiber.

[0016] Preferably, the preparation method of the aerogel composite material is: after mixing a silicon source, an alcohol solvent and water, adding an acid solution for hydrolysis reaction, and then adding an alkali solution for polycondensation reaction to obtain an aerogel composite material. The silicon source is ethyl silicate, the alcohol solvent is ethanol, and the mass ratio of the silicon source, the alcohol solvent and water is 1: (4-8): (2-4); and / or, the acid solution is hydrochloric acid, and the alkali solution is ammonia water. The pH value of the hydrolysis reaction is 1-3, the temperature is 30-60°C, and the hydrolysis reaction is carried out under stirring; and / or, the pH value of the polycondensation reaction is 8-10, the temperature is 10-60°C, and the time is 0.2-0.8h.

[0017] In a second aspect, the present invention provides, in an optional embodiment, an environmentally friendly aerogel thermal insulation pad, which is prepared using the above-mentioned production process.

[0018] Compared with the prior art, the present invention has one of the following beneficial effects:

[0019] 1. The present invention adds tannic acid as a hydrophobic agent and nano-silicon dioxide as an additive, which can synergistically improve the waterproof performance of the aerogel insulation pad.

[0020] 2. There are a large number of hydroxyl groups on the surface of nano-silica, which has strong surface activity. These hydroxyl groups can react with some hydrophobic modifiers, such as silane coupling agents and other substances. The alkoxy group of the silane coupling agent will react with the hydroxyl groups on the surface of nano-silica, and graft hydrophobic organic groups, such as alkyl groups, on its surface. When nano-silica exists in an aerogel system, this surface-modified nano-silica can reduce the affinity of the aerogel surface to water, thereby producing a hydrophobic effect.

[0021] 3. Tannic acid molecules contain a large number of polar groups such as phenolic hydroxyl groups, which can form hydrogen bonds with polymer chains in aerogels and hydroxyl groups on the surface of nano-silica. In the aerogel system, tannic acid is interconnected with aerogels and nano-silica through hydrogen bonds to form a tight network structure. This network structure changes the surface properties of aerogels and reduces the ability of the aerogel surface to adsorb water. At the same time, non-polar structures such as benzene rings in tannic acid molecules form a hydrophobic area on the surface of aerogels, thereby giving the aerogels hydrophobic properties.

[0022] 4. The present invention can further improve the waterproof performance of the aerogel thermal insulation pad by performing a heat pressing treatment on the dried aerogel thermal insulation pad. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] In the following examples and comparative examples, the method for preparing the aerogel composite material comprises the following steps:

[0025] After mixing 1kg of ethyl silicate, 5kg of ethanol and 3kg of water, hydrochloric acid was added to keep the pH value of the mixed solution at 1-3, and stirred at 30°C to allow a hydrolysis reaction to occur. After the hydrolysis reaction was completed, ammonia water was added to increase the pH value of the mixed solution to 9.2, and then a condensation reaction was carried out at 50°C for 0.6h to obtain an aerogel composite material.

[0026] In the following examples and comparative examples, ceramic fiber was purchased from Zibo Lumeng Insulation Materials Co., Ltd., model LM-01, and nano-silicon dioxide was purchased from Bohuasi Nanotechnology (Ningbo) Co., Ltd., model Brofos-S IO2-20.

[0027] Example 1

[0028] This embodiment provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0029] (1) adding 0.2 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.05 kg of tannic acid and 0.04 kg of nano-silicon dioxide, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0030] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 18 MPa and a temperature of 170°C for 40 minutes. After the hot pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0031] Example 2

[0032] This embodiment provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0033] (1) adding 0.2 kg of glass fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.05 kg of tannic acid and 0.04 kg of nano-silicon dioxide, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0034] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 18 MPa and a temperature of 170°C for 40 minutes. After the hot pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0035] Example 3

[0036] This embodiment provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0037] (1) adding 0.3 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.03 kg of tannic acid and 0.05 kg of nano-silica, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0038] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 18 MPa and a temperature of 170°C for 40 minutes. After the hot pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0039] Example 4

[0040] This embodiment provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0041] (1) adding 0.1 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.08 kg of tannic acid and 0.01 kg of nano-silica, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0042] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 18 MPa and a temperature of 170°C for 40 minutes. After the hot pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0043] Example 5

[0044] This embodiment provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0045] (1) adding 0.2 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.05 kg of tannic acid and 0.04 kg of nano-silicon dioxide, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0046] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 20 MPa and a temperature of 165°C for 50 minutes. After the hot-pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0047] Example 6

[0048] This embodiment provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0049] (1) adding 0.2 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.05 kg of tannic acid and 0.04 kg of nano-silicon dioxide, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0050] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 15 MPa and a temperature of 185°C for 30 minutes. After the hot-pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0051] Comparative Example 1

[0052] This comparative example provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0053] (1) adding 0.2 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.09 kg of tannic acid, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0054] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 18 MPa and a temperature of 170°C for 40 minutes. After the hot pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0055] Comparative Example 2

[0056] This comparative example provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0057] (1) adding 0.2 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.09 kg of nano-silicon dioxide, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0058] (2) The sol-gel mixture was cured at 100°C for 12 hours, then dried at -40°C for 24 hours, and finally hot-pressed at a pressure of 18 MPa and a temperature of 170°C for 40 minutes. After the hot pressing, an environmentally friendly aerogel thermal insulation pad was obtained.

[0059] Comparative Example 3

[0060] This embodiment provides a preparation process of an environmentally friendly aerogel thermal insulation pad, comprising the following steps:

[0061] (1) adding 0.2 kg of ceramic fiber to 1 kg of aerogel composite material, and then performing ultrasonic dispersion to uniformly disperse the fiber into the sol, and then adding 0.05 kg of tannic acid and 0.04 kg of nano-silicon dioxide, and reacting under stirring for 2 hours at a reaction temperature of 25° C. to obtain a sol-gel mixture;

[0062] (2) The sol-gel mixture was cured at 100°C for 12 hours and then dried at -40°C for 24 hours to obtain an environmentally friendly aerogel insulation pad.

[0063] Experimental example

[0064] The environmentally friendly aerogel thermal insulation pads prepared in Examples 1-6 and Comparative Examples 1-3 were soaked in water respectively. After soaking for 72 hours, they were taken out and the appearance changes of the thermal insulation pads were observed to check whether there was deformation or expansion. Then, the mass of the thermal insulation pads before and after soaking was weighed respectively. According to the formula: weight increase ratio = (mass of the thermal insulation pad after soaking - mass of the thermal insulation pad before soaking) / mass of the thermal insulation pad before soaking. The weight increase ratio was calculated. The results are shown in Table 1.

[0065] Table 1 Appearance changes, mass before and after immersion and increase ratio

[0066]

[0067]

[0068] Conclusion: By comparing the data of Example 1 with Comparative Examples 1 and 2, it can be seen that the addition of the hydrophobic agent tannic acid and the additive nano-silica can synergistically improve the waterproof performance of the aerogel insulation pad. By comparing the data of Example 1 and Comparative Example 3, it can be seen that hot pressing the insulation pad after drying can also improve the waterproof performance of the aerogel insulation pad. In addition, when the mass ratio of aerogel composite material, fiber material, additive and hydrophobic agent is 1:0.2:0.05:0.04, the waterproof performance of the aerogel insulation pad produced is the best.

[0069] Although the principles of the present invention are described in detail above in conjunction with the preferred embodiments of the present invention, those skilled in the art should understand that the above embodiments are merely explanations of the exemplary implementations of the present invention, and are not intended to limit the scope of the present invention. The details in the embodiments do not constitute limitations on the scope of the present invention, and any obvious changes such as equivalent transformations, simple replacements, etc. based on the technical solution of the present invention, without departing from the spirit and scope of the present invention, fall within the protection scope of the present invention.

Claims

1. A production process for an environmentally friendly aerogel thermal insulation pad, characterized in that: The following steps are involved: S1: adding fiber material to the aerogel composite material and then performing ultrasonic dispersion, and then adding additives and a hydrophobic agent to react to obtain a sol-gel mixture; S2: curing, drying and hot pressing the sol-gel mixture to obtain the environmentally friendly aerogel thermal insulation pad; Wherein, the hydrophobic agent is tannic acid, and the additive is nano-silicon dioxide; The pressure of the hot pressing treatment is 15MPa-20MPa; The temperature of the hot pressing treatment is 165-185°C and the time is 30-50min; The mass ratio of the aerogel composite material, the fiber material, the additive and the hydrophobic agent is 1: (0.1-0.3): (0.03-0.08): (0.01-0.05); The preparation method of the aerogel composite material is: After the silicon source, alcohol solvent and water are mixed, acid solution is added to carry out hydrolysis reaction, and then alkali solution is added to carry out polycondensation reaction to obtain an aerogel composite material.

2. The production process of the environmentally friendly aerogel thermal insulation pad according to claim 1, characterized in that: The mass ratio of the aerogel composite material, the fiber material, the additive and the hydrophobic agent is 1:0.2:0.05:0.

04.

3. The production process of the environmentally friendly aerogel thermal insulation pad according to claim 1, characterized in that: In step S1, the reaction time is 1-3 hours; and / or, The reaction is carried out under stirring conditions.

4. The production process of the environmentally friendly aerogel thermal insulation pad according to claim 1, characterized in that: The fiber material is selected from one or more of glass fiber, ceramic fiber, carbon fiber or plant fiber.

5. The production process of the environmentally friendly aerogel thermal insulation pad according to claim 1, characterized in that: The silicon source is ethyl silicate, the alcohol solvent is ethanol, and the mass ratio of the silicon source, the alcohol solvent and water is 1:(4-8):(2-4); and / or, The acid solution is hydrochloric acid, and the alkali solution is ammonia water.

6. The production process of the environmentally friendly aerogel thermal insulation pad according to claim 1, characterized in that: The pH value of the hydrolysis reaction is 1-3, the temperature is 30-60° C., and the hydrolysis reaction is carried out under stirring; and / or, The pH value of the polycondensation reaction is 8-10, the temperature is 10-60° C., and the time is 0.2-0.8 h.

7. An environmentally friendly aerogel thermal insulation pad, characterized in that: The product is prepared by the production process described in any one of claims 1 to 6.

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