TW202140629A - Method for producing a heat insulating material composed of a hydrophobic aerogel and the application thereof - Google Patents

Abstract

The invention provides a method for producing a heat insulating material composed of a hydrophobic aerogel, and the method includes the steps of: (1) a mixing step; (2) a hydrolysis step; (3) a condensation step; (4) an aging step; and (5) a drying step. In the method, a siloxane compound, an inorganic gel, and a halogen-free surfactant are mixed and then a sol-gel process is performed to produce the aerogel heat-insulating material without water-washing. The produced heat-insulating material has preferable strength, smooth appearance, and low shrinkage and can overcome the powder-dropping problem. By the provided method, an aerogel heat-insulating board can be produced, or an aerogel cold-resisting and heat-insulating blanket can be produced by mixing with a fiber or a foam material.

Description

Preparation method and application of hydrophobic aerogel heat insulation material

The invention relates to a preparation method of a hydrophobic aerogel heat insulation material, and particularly relates to a rapid preparation method of a hydrophobic aerogel heat insulation material with both low-temperature heat insulation and water-repellent properties.

Aerogel is a porous high-tech material with a three-dimensional network structure. It has low density (0.003 to 0.2g/cm ³ ), high specific surface area (500 to 2,000m ² /g) and low thermal conductivity (0.02 to 0.036). w/mK) and other characteristics. Due to the porosity of the aerogel can be as high as 95% and it contains a lot of air inside, it is transparent and has low heat transfer coefficient, low-frequency transmission rate and low dielectric constant, making the aerogel have excellent heat insulation, sound insulation, Electrical insulation, high adsorption and high efficiency filtration properties. However, in order to achieve the above-mentioned functions when aerogel is actually used, the aerogel powder must be evenly dispersed on a base material such as rock wool, glass fiber or carbon fiber to form an aerogel powder thermal insulation blanket. However, the currently used aerogel powder thermal insulation blankets are easy to fall off, and under repeated use in the temperature range of -200℃ to 200℃, water molecules will penetrate into the blanket when it is near the freezing point (0℃), resulting in the configuration of the thermal insulation blanket. The piping rusted and formed ice under freezing conditions, causing structural damage to the insulation blanket. In addition, the current common aerogel insulation blankets mostly use general organic adhesives to bond aerogel powders. Therefore, at a high temperature of 300°C, the organic adhesives in the blanket begin to crack and release a large amount of toxic gases and odors. . The above phenomenon is not only easy to cause corrosion of the pipelines of the equipment equipped with thermal insulation blankets, operator injury or environmental pollution. In addition, when the aerogel thermal insulation blanket has a significant cracking phenomenon, the thermal insulation effect will also be reduced.

The applicant’s existing method for preparing hydrophobic aerogels is based on sol-gel synthesis, and mainly uses olefin-based silicone compounds (such as methyltrimethoxysilane (MTMS) or methyltrimethoxysilane). After the precursors such as methyltriethoxysilane (MTES) are mixed with an organic solvent, an acid catalyst is added to carry out the hydrolysis reaction. After being hydrolyzed for a period of time, an alkali catalyst is added for condensation reaction, and the mixed solution will gradually form a gel during the condensation process. Then, the gel is solvent-replaced with a solvent such as n-butanol, n-hexanol, n-hexane, or cyclohexane, and dried at normal temperature and normal pressure or high temperature and normal pressure after the solvent replacement is completed. Alternatively, hydrophobic aerogels can also mix precursors such as silane oxygen compounds (such as tetraethoxysilane (TEOS) or tetramethoxysilane (TMOS)) with organic solvents, and then add them The acid catalyst performs the hydrolysis reaction. After being hydrolyzed for a period of time, an alkali catalyst is added to carry out the condensation reaction and gradually form a stable three-dimensional network structure during the condensation process. Finally, use solvents such as n-butanol, n-hexanol, n-hexane, or cyclohexane to perform solvent replacement on the network structure, and then perform hydrophobic modification with a hydrophobic modifier such as trimethylchlorosilane or hydrophobic silane to make hydrophobic The functional group structure is chemically bonded to the three-dimensional network structure. Finally, the solvent in the structure is dried using atmospheric drying technology to obtain a dry porous aerogel block.

Hydrophobic aerogels can also be prepared by using olefin-based silicone compounds (such as methyltrimethoxysilane or methyltriethoxysilane) to add water and stir to form a transparent solution. After being hydrolyzed for a period of time, add alkali When the catalyst reaches a pH value of 11.0, the condensation reaction is carried out directly, and a gel is gradually formed during the condensation process. Subsequently, it is aged for 20 to 24 hours in an aqueous solution at 70 to 80° C., and finally dried at normal temperature and normal pressure or high temperature and normal pressure to obtain the hydrophobic aerogel block material. In this process, the content of the olefin-based silicone compound is about 16% to 20%. The prepared hydrophobic polysilsesquioxane aerogel has a contact angle of 165 to 175 degrees and a density of 0.07 to 0.12 g/cm ³ . The porosity is 92 to 96%, and the pore size distribution is 120 to 1200 nm. In addition, the resulting aerogel has a relatively fluffy structure and is easy to fall off and crack, so it is more difficult to apply.

US Patent Application No. US20140076070A1 proposes a single layer of silicone and its separation, purification and concentration method. The single layer of silicone has a soft aerogel or Xerogel and is a single layer of aerogel that can dissolve substance molecules. This kind of silicon aerogel monolayer sheet utilizes the copolymerization of difunctional or trifunctional methylsiloxane starting materials and causes phase separation at the same time to form a Si-O network structure with continuous channels. The silicon aerogel monolayer sheet includes a continuous network structure of aerogel or Xerogel to form a silica gel network skeleton, with a continuous pore diameter of 1 to 50 μm, and a diameter of the silicone skeleton of 1 to 30 μm. However, although this kind of aerogel network structure is excellent, the strength is weak, and the preparation requires a long time for washing and replacement, which is not economical.

The aerogel particles proposed by the Mainland Invention Patent Publication No. CN101679657B and the manufacturing method thereof, the resulting hydrophobic aerogel particles have the following characteristics: (1) contain silicone particles; (2) at least 80% of the aerogel particles have less than 1 micron particle size; and (3) an average particle size of 0.1 micron to 1 micron. The latter part of the method for producing aerogel particles needs to be homogenized or wet milled. The starting aerogel particles may be surface treated during the grinding process to prevent aggregation or aggregation. In the preparation of the above-mentioned hydrophobic aerogel particles, aerogel homogenization or wet grinding is required by grinding processing, which is relatively difficult and cost-effective in the manufacturing process.

The preparation method of the hydrophobic silica aerogel thermal insulation composite material proposed by the Mainland Invention Patent Publication No. CN104556969A includes the following steps: (1) Preparation of silica sol: using siloxane as the precursor, adding organic solvent, Water and acid catalyst to obtain silica sol; (2) Preparation of composite gel: add flame retardant and infrared blocking agent to silica sol and stir evenly, and after adding alkali catalyst, immerse the inorganic fiber product in two Let stand in the silica sol; (3) Solvent replacement: replace the composite gel with an organic solvent; (4) Dry: dry the composite gel. In this process, it is necessary to use organic solvent to replace the aging composite gel for tens of hours, and the overall process time is too long to meet economic costs.

The porous material described in Japanese Patent Publication No. 200835648 and its preparation method are mainly synthesized by the sol-gel method of silanoxy compounds (such as TEOS) or silicate compounds (such as water glass) and organic solvents. The quality agent is modified to prepare a porous material, whereby the hydrophilic functional groups on the surface of the porous structure material are replaced with hydrophobic functional groups to prevent the aerogel from being broken by the surface tension of water, so it can be used at room temperature and normal pressure dry. In this technology, it is necessary to use organic structure for functional group replacement, and the overall process time is too long to meet economic costs.

The preparation method of the super water-repellent polysiloxane porous body described in Japanese Patent Publication No. 201548417 is mainly to solve the problem that the water-repellent property disappears after the flexible polysiloxane porous body comes into contact with an object. In the process, a combination consisting of a bifunctional silicon compound and a multifunctional silicon compound (such as a double-arm silicon compound and a three-arm silicon compound) is used, and the silicon compound is added to the solution system by the sol-gel method for hydrolysis and Condensation polymerization and phase separation of the system to obtain a polysiloxane porous body with a contact angle of 150 degrees, with a silica skeleton diameter of 1 to 3 μm.

The above-mentioned production processes of hydrophobic aerogel materials generally require multiple solvent replacements and the use of organic substances for hydrophobic modification. The related process technology is relatively difficult, the process cost is high, and the time required is too long, which is not cost-effective.

One purpose of the present invention is to remedy the problems of high cost and long process time that are not cost-effective due to conditions such as solvent replacement or water washing in the existing process. Specifically, the present invention is that in the process of silicon aerogel material manufacturing, especially in the process of block or sheet material, only hydrolysis and condensation reactions are required, and then after aging at high temperature, normal pressure and high temperature drying can be carried out, so the overall The production process does not require solvent replacement or water washing steps to obtain aerogel products, and the production process is simple and meets high economic benefits.

Another object of the present invention is to improve the shortcomings of the current aerogel thermal insulation blankets that they are easy to fall off when they are used. In particular, conventional aerogel thermal insulation blankets mainly use aerogel powder and inorganic fibers or organic fibers to interweave each other, so the structure is loose and the aerogel cannot be tightly combined with inorganic fibers or organic fibers, and it is very easy to use. Desserts. Although some hydrophobic aerogel thermal insulation blankets use organic adhesives or oil esters to spray on the thermal insulation blankets during the preparation process to reduce the phenomenon of powder loss, but at a high temperature above 150 ℃, the oil esters and organic esters inside the thermal insulation blankets Adhesives will begin to vaporize or thermally crack and produce a lot of odor and smoke.

Another object of the present invention is to add an aqueous inorganic glue solution during the aerogel preparation process to make the aerogel skeletons have a better binding force, so the prepared aerogel has proper strength and elasticity, and the product surface is smooth and does not drop powder. There is almost no shrinkage in the structure during the drying process, so it is not necessary to use expensive supercritical drying technology to produce hydrophobic aerogel blocks or sheets.

Another object of the present invention is that no chloride-containing ionic surfactant is added during the aerogel preparation process, so the prepared aerogel can be dried directly after aging without lengthy water washing and replacement. In addition, the prepared aerogel has no odor and release of toxic substances at a temperature higher than 100°C, so the overall manufacturing process is simple, economical, and safe.

Another object of the present invention is to combine inorganic fibers, organic fibers or foams in the aerogel preparation process to obtain products such as aerogel insulation boards or insulation blankets that have both hydrophobicity and high heat insulation. In addition, a small amount of aqueous inorganic glue solution is added during the manufacturing process to combine the aerogel with inorganic fibers, organic fibers or foams with inorganic glue, so the prepared aerogel blanket hardly loses debris during subsequent use.

Another object of the present invention is that the aerogel condensation solution obtained during the preparation process can be directly sprayed, sucked or glued onto general inorganic fiber cloth or inorganic fiber blanket (such as glass fiber, ceramic fiber, rock wool fiber and carbon fiber). , In order to obtain a water-repellent aerogel thermal insulation blanket with softness, heat insulation and flame-proof properties, and then used as a thermal insulation cloth or used for indoor and outdoor heat insulation.

In view of this, the present invention proposes a simple method for preparing hydrophobic aerogel thermal insulation material. The method includes the following steps: (1) Mixing step: mixing silicone compounds, a small amount of inorganic glue aqueous solution and a small amount of halogen-free ion Surfactant is added to a mixed solvent and dispersed in the mixed solvent to form a uniform mixed solution; (2) Hydrolysis step: Add an acid catalyst solution to the mixed solution for hydrolysis; (3) Condensation step: An alkali catalyst solution is added to the hydrolyzed mixed solution for condensation reaction, in which silicone compounds form stable hydrogel primary particles with a particle size of about 5 to 10 nanometers, and then combine with each other to grow into a hydrogel of 100 to 1000 nanometers The secondary particles increase the viscosity of the mixed solution to become a solution-like sol. Finally, the secondary particles of the hydrogel form a wet gel with a network structure; (4) Aging step: age the wet gel with a network structure in a specific temperature range. Form a more stable gel structure; and (5) Drying step: The gel structure is evaporated and dried under normal pressure to remove water and other solvents. After the molecules are slowly detached, they are then quickly dried at a high temperature of 90-150°C to obtain a hydrophobic aerogel insulation material.

Further, in the condensation step, when the mixed solution becomes a solution sol, the solution sol is quickly injected or impregnated into the inorganic fiber blanket, organic fiber blanket or organic foaming material, so that the solution sol fills the inorganic fiber blanket , Organic fiber blanket or organic foam material, and then put the inorganic fiber blanket, organic fiber blanket or organic foam material filled with solution sol to stand still, so that the secondary particles of hydrogel in the solution sol are placed on the inorganic fiber blanket, The organic fiber blanket or organic foam material gradually condenses to form a wet gel.

Further, the silicone compound is one or more selected from the group consisting of: alkoxysilane, alkene-based silicone compound, and R-based silicone oligomer; wherein the silicone compound is such as ：Tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS). The above-mentioned molecules mainly provide aerogel network binding point density in this article to increase the strength of aerogel structure; olefin-based silicon Oxyane compounds such as: methyl trimethoxy silane (MTMS) or methyl triethoxy silane (MTES), the above-mentioned molecules mainly provide the hydrophobic properties of the aerogel in this article to increase the environmental stability of the soft aerogel structure Sex; R-based silicone oligomolecules such as: polydimethyl silicone (PDMS) or silicone precursor (DMDMS), the above molecules in this article mainly provide aerogel elasticity, flexibility and increase the environmental stability of the aerogel structure , The above R group-is a functional group connecting the ends of the silicone molecular chain, and this functional group can be used for excellent bonding with other fiber substrates.

Further, the mixed solvent is one or more substances selected from the group consisting of water and alcohols.

Furthermore, in addition to providing the acid ions required in the hydrolysis process, the aqueous inorganic glue solution also provides the bonding strength between the silicone gel molecules, so that the network skeleton structure of the wet gel provided during the condensation and aging process has a stronger bonding strength, thereby improving The strength and surface smoothness of aerogel products can solve the problem of aerogel powder falling.

Further, the acid catalyst used for hydrolysis includes one or more components selected from the group consisting of sulfuric acid, phosphoric acid, nitric acid, and boric acid.

Furthermore, the halogen-free ion surfactant is a chloride-free surfactant and contains one or more components selected from the group consisting of cationic surfactants, anionic surfactants, zwitterionic surfactants and non-chloride surfactants. Ionic surfactant.

Further, the alkali catalyst used for condensation includes one or more components selected from the group consisting of sodium hydroxide, potassium hydroxide, sodium bicarbonate, and sodium dihydrogen carbonate.

Furthermore, the alkali catalyst solution used for condensation can be an aqueous solution or a mixed solution (such as one or more mixed of water, secondary water, alcohols, and alkanes) containing a hydrophilic solvent and a hydrophobic solvent according to the requirements of the process. ), which can control the initial molecular aggregation of the hydrogel in the mixed solution to form secondary particles and the size of the network skeleton of the wet gel. Specifically, the coordination ratio of the hydrophilic solvent and the hydrophobic solvent is used to control the interaction between the alkali catalyst solution and the silicone compound molecules, thereby controlling the microphase separation and gelation of the silicone compound molecules during the aggregation and bonding process. Chemical behavior, thereby controlling the molecular particle size and pore distribution of the formed wet gel structure.

Furthermore, in the aging step, a 70°C to 90°C high temperature aging device is used to perform the aerogel wet gel aging process, and the part of the wet gel structure that has not been combined to form a network structure is aged through the high temperature of 70°C to 90°C. Generally speaking, the higher the temperature, the faster the aging rate of the wet gel, and the aging efficiency of the wet gel herein can be increased by about 30 to 70%.

Furthermore, this method uses general normal temperature and normal pressure or high temperature and normal pressure to dry the hydrophobic aerogel. After drying, an aerogel material with both water repellency and heat insulation properties can be obtained. On the whole, there is no washing step in the method, and the simple process can quickly shorten the overall process time to 8 to 24 hours to quickly prepare a dry hydrophobic aerogel sheet or block, thereby improving production efficiency.

Furthermore, in the present technology, the silica gel condensation solution is combined with media such as inorganic fiber blankets, organic fiber non-woven blankets or organic foam materials to prepare aerogel thermal insulation blankets. In the condensation step, a small amount of inorganic glue aqueous solution can be added again to make the solution system form an aerogel/inorganic glue composite solution, and then the relevant solution can be directly filled on the inorganic fiber blanket, organic fiber non-woven blanket or organic foam material medium, and then After aging, it can be dried under normal pressure to prepare an aerogel insulation blanket or a high water-repellent aerogel/inorganic fiber composite board and other application products.

Further, the inorganic adhesive includes one or more selected from the group consisting of phosphate, silicate, sulfate, borate, and metal oxide. Specifically, phosphates such as zirconium phosphate or phosphoric acid-copper oxide, silicates such as aluminum silicate or water glass, and metal oxides such as copper, aluminum, or zirconium metal element oxides.

Further, the inorganic fiber blanket includes one or more materials selected from the group consisting of ceramic fiber, glass fiber, carbon fiber, oxidized fiber, and rock wool fiber.

Further, the organic fiber blanket or organic foaming material includes one or more materials selected from the group consisting of polypropylene, polyester, polyamide, polyurethane, polyurethane, polyurea, and polycyanamide.

The invention has the following effects:

1. The hydrophobic aerogel material prepared by the present invention utilizes an aqueous inorganic glue solution to provide acid radical ions of the hydrolysis system in the hydrolysis step to increase the hydrolysis rate. Furthermore, the added inorganic glue molecules can be mixed with the hydrogel particles and condense with the hydrogel particles during the condensation process to form a network skeleton structure, and the inorganic rubber molecules are distributed on the surface of the network skeleton structure to form a Inorganic glue protective film. In this way, the inorganic glue protective film can not only provide proper strength of the subsequently prepared hydrophobic aerogel material, but also increase its heat resistance temperature, thereby enhancing the application value of the hydrophobic aerogel material.

2. The density, particle size, porosity, and pore size of the hydrophobic aerogel material obtained by the preparation method of the present invention can depend on the preparation conditions (such as: type or content of silicone compound, type of olefin-based silicone compound or The content, R-based-silicone oligomolecule type or content, solvent type or content, inorganic rubber type or content, surfactant type or content, acid catalyst or alkali catalyst type or content, and stirring rate, etc.).

3. The preparation method of the present invention utilizes the addition of a small amount of inorganic rubber molecules to mix with silicone compounds, so that the inorganic rubber molecules are mixed with the silicone compound molecules in the condensation process to form a network skeleton structure, and then when it is dried to remove moisture, Due to the combination of the silicone compound molecules in the network skeleton structure and the glue-free molecules, the network skeleton structure is stable, so the structure and appearance size of the aerogel material almost unchanged after drying. Therefore, the hydrophobic aerogel sheet and block prepared by the method have higher stability.

4. The method of the present invention does not require the use of a large amount of solvents for solvent replacement, or a large amount of water for washing steps, and the overall manufacturing process is simple, which can significantly shorten the overall preparation time of aerogels, thereby improving production efficiency.

5. The solution-like sol containing inorganic glue prepared by the method of the present invention can be directly combined with inorganic fiber blankets, organic fiber blankets or organic foaming materials. The sol is directly filled into the fiber blanket or foaming material, and then dried under normal pressure to make an aerogel/inorganic fiber insulation blanket, aerogel/organic fiber blanket or aerogel/organic foam pad.

6. Compared with the conventional method, the method of the present invention reduces the lengthy water washing replacement step, and the overall process time is reduced by 50%. In the method of the present invention, inorganic glue and surfactant are added to strengthen the strength of the aerogel, so the prepared aerogel sheet or thermal insulation blanket has appropriate strength and elasticity, and the surface of the overall structure is smooth and does not drop powder. The temperature resistance range of the product developed by the method of the invention is from -300°C to 350°C, and it has both low temperature resistance and high heat insulation properties. In addition, the product developed by the method of the present invention can load more than 3 kilograms under a weight of 3.3 grams, and has a thermal conductivity of about 0.02 to 0.036 W/mK.

Please refer to FIG. 1, which is a method for preparing an aerogel-containing thermal insulation material containing inorganic glue according to a first embodiment of the present invention, which includes the following steps: a mixing step (S11), a hydrolysis step (S12), a condensation step (S13), and an aging step (S14), drying step (S15), thereby preparing high-strength, non-powdering, low-temperature and cold-resistant hydrophobic aerogel insulation boards or tiles.

Mixing step (S11): mixing one or a mixture of one or more of silicone compounds, olefin-based silicone compounds, and R-based silicone oligomers with a small amount of aqueous inorganic glue solution, a small amount of halogen-free ion surfactant, and a mixture The solvents are stirred and mixed to form a mixed solution. The silicone compound is, for example, tetramethoxysilane or tetraethoxysilane; the olefin-based silicone compound is, for example, methyltrimethoxysilane or methyltriethoxysilane; Methyl silicone or silicone precursor (DMDMS), where the R group-is a functional group, which is connected to the end of the silicone molecular chain, and contains: acid group -COOH, amino group -NH ₂ , hydroxyl group -OH, epoxy group -COH -COH, isocyanate group -N=C=O, the carbon number is from C1 to C6. Based on the total content of the mixed solution, the total content of silicone compounds, olefin-based silicone compounds and R-based silicone oligomers is between 3.0 mol% and 40.0 mol%, mixed solvent, inorganic glue solution and halogen-free ion The total content of the surfactant is between 97.0 mol% and 60.0 mol%.

The mixed solvent used in the mixing step (S11) is one or more substances selected from the group consisting of water, treated water, deionized water, alcohols, aromatics, and alkanes. Specifically, alcohols such as ethanol, aromatics such as toluene, alkanes such as n-hexane or cyclohexane, and surfactants such as cetyltrimethylammonium halide. In the mixing step (S11), the silicone compound, olefin-based silicone compound or R-based silicone oligomer can be mixed with the inorganic gel molecule. In addition, since the inorganic glue molecules are metal compounds, the inorganic glue molecules in the mixed solution will dissociate into metal ions and acid ions or alkali ions in the mixed solution. Based on the total volume of the mixed solution, the concentration of the aqueous inorganic glue solution is 0.05 to 3.0 vol%.

In the mixed solution, the purpose of containing the surfactant is to reduce the phase separation behavior of the mixed solution. The surfactant includes one or more components selected from the group consisting of cationic surfactants, anionic surfactants, zwitterionic surfactants, and nonionic surfactants. Based on the total volume of the mixed solution, the surfactant concentration is 0.01 to 0.5 vol%.

Hydrolysis step (S12): adding an acid catalyst to the mixed solution to carry out the hydrolysis reaction. Wherein, the acid catalyst has a content ratio of 0.0001:1 to 0.01:1 between the acid radical ions generated by the dissociation of the inorganic gel and the silicone compound, the olefin-based silicone compound, and the R group-silicone oligomolecule as a whole. Moreover, the higher the acid radical ion concentration, the higher the hydrolysis efficiency, but the ion concentration will affect the dielectric properties of the final product.

Condensation step (S13): adding an alkali catalyst solution to the hydrolyzed mixed solution for condensation reaction. The alkali catalyst solution used in the condensation step (S13) can be an aqueous solution or a mixed solution (such as water, secondary water, alcohols, aromatics, alkane One or more of the same), and the alkali catalyst can promote the phase separation and condensation of the mixed solution gradually. During the condensation process, the silicone compound molecules and the inorganic colloid molecules in the solution will phase separate in the solution environment. The phase separation will cause the silicone compound molecules and the inorganic colloid molecules to aggregate to form aerosols with a particle size of several nanometers. The initial particles of aerogel, and then the initial molecules of several nanometers of aerogel are stacked and fused with each other to form aerogel secondary particles of hundreds of nanometers. Under this condition, the viscosity of the solution will gradually rise to form a solution-like sol (solution-like sol). sol). Then, the solution-like sol is poured into a different container and then left to stand to allow the solution-like sol to condense again to form a wet gel structure.

Aging step (S14): the wet gel structure formed in the condensation step (S13) is aged at a specific temperature to promote the wet gel structure to be more stable. For example, the aging temperature is, for example, 50 to 95°C, and further, for example, 70 to 90°C.

Drying step (S15): After the remaining liquid in the wet gel structure is removed by high temperature distillation or the remaining liquid is filtered out with a filter, the hydrophobic aerogel can be obtained by rapid drying at 90 to 150°C and normal pressure. Insulation material. Further, a 90-250°C fluid bed dryer, a constant temperature oven, a drum dryer, a stirring dryer, or a vacuum dryer can be used for drying to accelerate the drying rate.

Please refer to FIG. 2, which is a method for preparing an aerogel thermal insulation material containing inorganic glue according to a second embodiment of the present invention, which includes the following steps: a mixing step (S21), a hydrolysis step (S22), a condensation step (S23), and a compounding step (S24), aging step (S25), and drying step (S26) to prepare high-strength, non-powder, low-temperature and cold-resistant hydrophobic aerogel/inorganic fiber insulation blanket, aerogel/organic fiber Blanket or aerogel/organic foam pad.

Mixing step (S21): mixing one or a mixture of one or more of silicone compounds, olefin-based silicone compounds, and R-based silicone oligomers with a small amount of aqueous inorganic glue solution, a small amount of halogen-free ion surfactant, and a mixture The solvents are stirred and mixed to form a mixed solution. The silicone compound is, for example, tetramethoxysilane or tetraethoxysilane; the olefin-based silicone compound is, for example, methyltrimethoxysilane or methyltriethoxysilane; Methyl silicone or silicone precursor (DMDMS), where the R group-is a functional group, which is connected to the end of the silicone molecular chain, and contains: acid group -COOH, amino group -NH ₂ , hydroxyl group -OH, epoxy group -COH -COH, isocyanate group -N=C=O, the carbon number is from C1 to C6. Based on the total content of the mixed solution, the total content of silicone compounds, olefin-based silicone compounds and R-based silicone oligomers is between 3.0 mol% and 40.0 mol%, mixed solvent, inorganic glue solution and halogen-free ion The total content of the surfactant is between 97.0 mol% and 60.0 mol%.

The mixed solvent used in the mixing step (S21) is one or more substances selected from the group consisting of water, alcohols, aromatics and alkanes. Specifically, alcohols such as ethanol, aromatics such as toluene, alkanes such as cyclohexane, and surfactants such as cetyltrimethylammonium halide. In the mixing step (S21), the silicone compound, olefin-based silicone compound, or R-based silicone oligomer can be mixed with the inorganic gel molecule. In addition, since the inorganic glue molecules are metal compounds, the inorganic glue molecules in the mixed solution will dissociate into metal ions and acid ions or alkali ions in the mixed solution. Based on the total volume of the mixed solution, the concentration of the aqueous inorganic glue solution is 0.05 to 3.0 vol%.

In the mixed solution, the purpose of containing the surfactant is to reduce the phase separation behavior of the mixed solution. The surfactant includes one or more components selected from the group consisting of cationic surfactants, anionic surfactants, zwitterionic surfactants, and nonionic surfactants. Based on the total volume of the mixed solution, the surfactant concentration is 0.005 to 0.5 vol%.

Hydrolysis step (S22): adding an acid catalyst to the mixed solution to carry out the hydrolysis reaction. Wherein, the acid catalyst has a content ratio of 0.0001:1 to 0.01:1 between the acid radical ions generated by the dissociation of the inorganic gel and the silicone compound, the olefin-based silicone compound, and the R group-silicone oligomolecule as a whole. Moreover, the higher the acid radical ion concentration, the higher the hydrolysis efficiency, but the ion concentration will affect the dielectric properties of the final product.

Condensation step (S23): adding an alkali catalyst solution to the hydrolyzed mixed solution for condensation reaction. The alkali catalyst solution used in the condensation step (S23) can be an aqueous solution or a mixed solution (such as water, secondary water, alcohols, aromatics, alkane One or more of the same), and the alkali catalyst can promote the phase separation and condensation of the mixed solution gradually. During the condensation process, the silicone compound molecules and the inorganic colloid molecules in the solution will phase separate in the solution environment. The phase separation will cause the silicone compound molecules and the inorganic colloid molecules to aggregate to form aerosols with a particle size of several nanometers. The initial particles of aerogel, and then the initial molecules of several nanometers of aerogel are stacked and fused with each other to form aerogel secondary particles of hundreds of nanometers. Under this condition, the viscosity of the solution will gradually rise to form a solution-like sol (solution-like sol). sol).

Compounding step (S24): when the solution is mixed in the condensation reaction to form a solution sol, the solution sol is quickly injected or impregnated into the inorganic fiber blanket, organic fiber blanket, or organic foaming material, so that the liquid sol is filled with the inorganic In the fiber blanket, organic fiber blanket or organic foaming material, then the inorganic fiber blanket, organic fiber blanket, or organic foaming material filled with the solution sol is allowed to stand still, so that the solution sol is placed on the inorganic fiber blanket, organic fiber blanket or The organic foam material gradually condenses to form a wet gel structure. In this step, the inorganic glue molecules will be formed between the aerogel secondary particles and the fiber or foaming material as a bonding medium, so the subsequent prepared aerogel/inorganic fiber blanket, aerogel/organic fiber blanket or The aerogel/organic foam material has a strong internal structure, so that although the derived products have high structural porosity and low density, they are not easy to fall off dust, are not easy to break, and have better strength, so they have excellent heat insulation nature.

Aging step (S25): In the compounding step (S24), the wet gel structure filled in the inorganic fiber blanket, organic fiber blanket or organic foam material is aged at a specific temperature to promote the wet gel structure to become more stability. For example, the aging temperature is, for example, 50 to 95°C, and further, for example, 70 to 90°C.

Drying step (S26): After the remaining liquid in the wet gel structure is removed by high-temperature distillation or the remaining liquid is filtered out with a filter, the hydrophobic aerogel can be obtained by rapid drying under normal pressure at 90 to 150°C. Insulation material. Further, a 90-250°C fluid bed dryer, a constant temperature oven, a drum dryer, a stirring dryer, or a vacuum dryer can be used for drying to accelerate the drying rate.

Thereby, the first embodiment can prepare a hydrophobic aerogel sheet or a hydrophobic aerogel block with high strength and no chipping. In addition, in the second embodiment, aerogel/inorganic fiber thermal insulation blanket, aerogel/organic fiber thermal insulation blanket, or aerogel/foam material are prepared by combining a solution-like sol with a large number of fiber blankets or foaming materials. Thermal insulation pad to improve the application properties of aerogel materials. Especially as a low-temperature protection composite material or low-temperature aerogel insulation blanket to enhance the industrial value of aerogel materials.

Please refer to Figure 3, using a general camera to take photos of different styles of hydrophobic aerogel heat insulation panels and heat insulation tiles prepared. The photographs taken show that the method can prepare hydrophobic aerogel plates or blocks of different sizes or thicknesses.

Please refer to Figure 4, using a general camera to photograph different types of aerogel/inorganic fiber insulation blankets, aerogel/organic fiber insulation blankets or aerogel/organic foam insulation blankets prepared. The photos taken show that the produced aerogel/inorganic fiber thermal insulation blanket, aerogel/organic fiber thermal insulation blanket or aerogel/organic foam thermal insulation pad have proper strength and smooth surface.

Please refer to Figure 5, using a scanning electron microscope to observe the cut surface of the inorganic glue aerogel insulation material prepared by this method and the inorganic glue-containing hydrophobic aerogel/inorganic fiber insulation blanket. The scanning electron microscope photos show that the method is added with inorganic glue, so that the fine structure of the prepared hydrophobic aerogel heat insulation material is on the surface of the fine structure, except for the network skeleton structure connected by several micron silica particles. There is also an obvious non-glue film coating to provide the aggregation strength of the silicone particles. In addition, scanning electron micrographs also show that the fine structure of the inorganic glue-containing hydrophobic aerogel/inorganic fiber thermal insulation blanket shows that the inorganic glue-containing hydrophobic aerogel obviously coats the surface of the fiber to form a thin film. The aerogel film is then connected with other silicone particles to form a net-like skeleton structure of aerogel in the middle of the fiber network. The overall structure has excellent bonding properties between fibers and aerogel molecules, so it is less likely to produce debris during application. The problem.

Please refer to Figure 6 to illustrate the load-bearing capacity of the inorganic adhesive aerogel heat insulation material prepared by this method. The photo shows that it can hold a weight of nearly 2885 grams with a volume of 30 milliliters and a weight of 4.0 grams. On the upper side, and there is no cracking phenomenon after high load is applied, indicating that the inorganic glue aerogel heat insulation material prepared by this method has excellent load resistance characteristics.

Please refer to Fig. 7, which shows that the inorganic glue aerogel heat insulation material prepared by this method weighs 153.4 g under the volume of 10.5 cm x 10.5 cm x 9.5 cm. After conversion, it can be seen that the density of the prepared inorganic rubber aerogel heat insulation material is about 0.146 g/cm ³ , which indicates that it has excellent light weight.

Please refer to Figure 8. The inorganic glue aerogel insulation brick prepared by this method will float on the water surface. The photo shows that about 85% of the volume of the inorganic glue aerogel insulation brick floats on the water surface and completely repels the water. It has excellent water repellent properties and low density.

Based on the description of the above embodiments, when one can fully understand the production and application of the present invention and the effects of the present invention, the above embodiments are only the preferred embodiments of the present invention, and the implementation of the present invention cannot be limited by this. The scope, that is, simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the description of the invention, are all within the scope of the present invention.

<First embodiment> (S11): Mixing steps (S12): Hydrolysis step (S13): Condensation step (S14): Aging step (S15): Drying step <Second embodiment> (S21): Mixing step (S22): Hydrolysis step (S23): Condensation step (S24): Compounding steps (S25): Aging step (S26): Drying step

FIG. 1 is a schematic diagram of the preparation process of the hydrophobic aerogel low-temperature thermal insulation material according to the first embodiment of the present invention. 2 is a schematic diagram of the preparation process of the hydrophobic aerogel low-temperature thermal insulation material according to the second embodiment of the present invention. Figure 3 is a photograph of the hydrophobic aerogel heat insulation board and the heat insulation brick prepared by the present invention. Figure 4 is a photograph of the appearance of the aerogel/inorganic fiber insulation blanket, aerogel/organic fiber insulation blanket or aerogel/organic foam insulation blanket prepared by the present invention. Figure 5 is a scanning electron microscope photograph for comparing the cut surface of the inorganic glue aerogel heat insulation material prepared by this method and the inorganic glue hydrophobic aerogel/inorganic fiber heat insulation blanket. Fig. 6 is a photograph of the aerogel insulation material prepared by the present invention, to illustrate that it can load cement bricks with a weight of more than 3000 grams under a volume of 30 milliliters and a weight of 3.3 grams without breaking. Fig. 7 is a photograph of the inorganic adhesive aerogel thermal insulation brick prepared by the present invention to illustrate its weight in a volume of 10.5 cm x 10.5 cm x 9.5 cm. Fig. 8 is a photograph of the inorganic glue aerogel thermal insulation brick prepared by the present invention floating on the water surface.

(S11): Mixing step

(S12): Hydrolysis step

(S13): Condensation step

(S14): Aging step

(S15): Drying step

Claims (10)

A preparation method of hydrophobic aerogel heat insulation material, which includes: (1) Mixing step: adding silicone compounds, a small amount of inorganic glue aqueous solution and a small amount of halogen-free ion surfactant to a mixed solvent, and disperse them in the mixed solvent to form a uniform mixed solution; (2) Hydrolysis step: adding an acid catalyst solution to the mixed solution to carry out the hydrolysis reaction; (3) Condensation step: Add an alkali catalyst solution to the hydrolyzed mixed solution to carry out a condensation reaction, wherein the silicone compound forms stable hydrogel initial particles with a particle size of about 5 to 10 nanometers, which are then combined with each other to grow Hydrogel secondary particles of 100 to 1000 nanometers increase the viscosity of the mixed solution to become a solution-like sol, and finally the hydrogel secondary particles form a network structure of wet gel; (4) Aging step: aging the wet gel of the network structure in a specific temperature range to form a more stable gel structure; and (5) Drying step: evaporate and dry the gel structure under normal pressure to remove the solvent. In the drying process, the water molecules in the gel structure are slowly separated by an environment of about 50-90℃, and then 90 -150℃ high temperature and rapid drying to obtain hydrophobic aerogel insulation material. The preparation method according to claim 1, wherein in the condensation step, when the mixed solution becomes the solution sol, the solution sol is injected or impregnated into an inorganic fiber blanket, an organic fiber blanket or an organic foam In the material, the solution-like sol is filled with the inorganic fiber blanket, the organic fiber blanket or the organic foaming material, and then the inorganic fiber blanket, the organic fiber blanket or the organic foaming material filled with the solution-like sol is allowed to stand still , The secondary particles of the hydrogel in the solution sol are gradually condensed on the inorganic fiber blanket, organic fiber blanket, or organic foaming material to form the wet gel. The preparation method according to claim 1, wherein the silicone compound contains one or more selected from the group consisting of: alkoxysilane, olefin-based siloxane compound, and R group- Silicone oligomer; the silicone compound is tetramethoxysilane or tetraethoxysilane, the olefin-based silicone compound is methyltrimethoxysilane or methyltriethoxysilane; the R group-silicone The oligomolecule is polydimethyl silicone (PDMS) or silicone precursor (DMDMS), wherein the R group-is a functional group connected to the end of the silicone molecular chain, which includes: acid group -COOH, amino group -NH _2. Hydroxy-OH, epoxy-COH-COH, isocyanate-N=C=O, and the carbon number is from C1 to C6. The preparation method according to claim 1, wherein the mixed solvent is one or more substances selected from the group consisting of water, treated water, deionized water, ethanol, toluene, n-hexane, cyclohexane, The surfactant is cetyltrimethylammonium halide. The preparation method according to claim 1, wherein the inorganic glue contains one or more selected from the group consisting of phosphate, silicate, sulfate, borate, and metal oxide, the phosphate It is zirconium phosphate or phosphoric acid-copper oxide, the silicate is aluminum silicate or water glass, and the metal oxide is an oxide of copper, aluminum, or zirconium metal element. The preparation method according to claim 1, wherein the halogen-free ion surfactant is a chloride ion-free surfactant and contains one or more components selected from the group consisting of: cationic surfactant, anionic surfactant Agent, zwitterionic surfactant and nonionic surfactant. The preparation method according to claim 1, wherein the temperature of the aging step is 50 to 95°C. The preparation method according to claim 2, wherein the inorganic fiber blanket comprises one or more materials selected from the group consisting of ceramic fiber, glass fiber, carbon fiber, oxidized fiber and rock wool fiber, and the organic fiber blanket Or the organic foaming material includes one or more materials selected from the group consisting of polypropylene, polyester, polyamide, polyurethane, polyurethane, polyurea and polycyanamide. The preparation method according to claim 1, wherein based on the total volume of the mixed solution, the concentration of the aqueous inorganic colloid solution is 0.05 to 3.0 vol%. The preparation method according to claim 1, wherein based on the total volume of the mixed solution, the concentration of the surfactant is 0.005 to 0.5 vol%.

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