A method for preparing a fly ash modified silica aerogel and a fly ash soundproof coating composition

Abstract

The application relates to the technical field of fly ash, and particularly provides a preparation method of fly ash modified silicon dioxide aerogel and a fly ash sound insulation coating composition. In the preparation method of the fly ash modified silicon dioxide aerogel, fly ash and a silicon source are dispersed together in advance in the preparation process of the silicon dioxide aerogel to form a uniform dispersion liquid, and then steps of hydrolysis and condensation, aging, replacement, modification, drying and the like are carried out. The fly ash modified silicon dioxide aerogel is used for preparing the sound insulation coating, sound insulation coating with a higher sound insulation coefficient can be obtained, and compared with the case that fly ash is used as a sound insulation material, the coating has better mechanical strength.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fly ash, in particular, relates to a preparation method of fly ash modified silica aerogel and a fly ash sound insulation coating composition. BACKGROUND

[0002] Fly ash is fine ash collected from flue gas after coal combustion, and the main components are oxides, including SiO2, Al2O3, FeO, Fe2O3, CaO, TiO2, etc. Fly ash is the main solid waste discharged by coal-fired power plants and is one of the industrial waste residues with large current discharge in China. Therefore, the resource utilization of fly ash has important practical significance for environmental protection and pollution reduction.

[0003] Fly ash has high activity, mainly from active SiO2 and active Al2O3, and can undergo hydration under certain alkaline conditions, so it is currently more used as an admixture for concrete. The existing technology also reports the use of the porous structure of fly ash as a sound insulation material. Document one discloses a high-elongation sound insulation two-component water-based waterproof coating composed of liquid material and powder material, and the powder material contains 20-30% fly ash. Document two discloses a high-sound insulation epoxy resin building material for building, which includes fly ash, silicon oxide and calcium oxide. Document three discloses a shell powder-based light sound insulation exterior wall coating, in which fly ash is treated with HCl solution and HF solution to form an acid and alkali resistant insoluble shell of AlF3, FeF3, CaF2 and MgF2 on the surface of fly ash.

[0004] Document one: Chinese invention patent CN107964296A.

[0005] Document two: Chinese invention patent CN113667372A.

[0006] Document three: Chinese invention patent CN115340322A.

[0007] However, the bulk density of porous structure fly ash is small, the gap between particles is large, and the oil absorption is large. When the addition amount of fly ash in the coating is large, although the sound insulation performance of the coating is good, the mechanical properties of the coating layer after curing of the coating are poor, the strength is low, and the quality is brittle. SUMMARY

[0008] In order to solve the above problems, the present application provides a preparation method of fly ash modified silica aerogel and a fly ash sound insulation coating composition.

[0009] The technical scheme adopted by the present application is as follows:

[0010] A preparation method of fly ash modified silica aerogel, comprising the following steps:

[0011] The fly ash and silicon source are dispersed into an alcohol aqueous solution, acid is added for hydrolysis, and then base is added for condensation to obtain a wet gel; the wet gel is aged, replaced, soaked into a modification solution for modification, washed, dried, and then obtained.

[0012] Preferably, the weight ratio of the fly ash, the silicon source, and the alcohol aqueous solution is 0.5-10:1:20-100.

[0013] Preferably, the average particle size of the fly ash is 0.5-100 μm.

[0014] Preferably, the silicon source is selected from one or several combinations of alkyl orthosilicate, water glass, and trialkoxysilane coupling agent.

[0015] Preferably, the alcohol aqueous solution is composed of anhydrous ethanol and water in a volume ratio of 8:2-9:1.

[0016] Preferably, the modification solution is selected from a n-hexane solution of trimethylchlorosilane with a concentration of 1-100 g / L.

[0017] Preferably, the modification solution contains one or several combinations of amino-containing chlorosilane and amino-containing alkoxysilane with a concentration of 1-50 g / L.

[0018] A fly ash soundproof coating composition contains 10-40% of the fly ash modified silica aerogel prepared by the preparation method of the fly ash modified silica aerogel according to any one of the technical solutions.

[0019] Preferably, the film-forming main material of the fly ash soundproof coating composition is selected from one or several combinations of acrylic resin, modified acrylic resin, polyurethane, modified polyurethane, epoxy resin, modified epoxy resin, polysiloxane, and ethylene-vinyl acetate.

[0020] A fly ash soundproof coating composition contains, by weight, 100 parts of cement, 200-300 parts of sand, 0.5-10 parts of redispersible latex powder, 0.5-10 parts of cellulose ether, and 20-200 parts of the fly ash modified silica aerogel according to any one of the technical solutions.

[0021] In summary, the present application has the following beneficial effects:

[0022] 1. In order to solve the problem of large oil absorption of fly ash, the present application adds fly ash in the preparation of silica aerogel, and finds that the fly ash modified silica aerogel obtained can combine the characteristics of fly ash and silica aerogel, and has good mechanical strength and low oil absorption while retaining high porosity.

[0023] 2. This application combines the porous structure of fly ash particles with the silica aerogel structure, resulting in a fly ash-modified silica aerogel with a good porous structure. When the fly ash-modified silica aerogel of this application is used to prepare sound-insulating coatings, it is found that a high addition amount can be achieved, and the sound insulation effect is good. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below.

[0025] Throughout this specification, unless otherwise specified, the terminology used herein should be understood as having the meaning commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In the event of any conflict, this specification shall prevail.

[0026] On one hand, this application provides a method for preparing fly ash-modified silica aerogel. In the preparation process of silica aerogel, fly ash and a silicon source are dispersed together to form a uniform dispersion, followed by hydrolysis-condensation, aging, displacement, modification, and drying steps. Specifically, it includes the following steps:

[0027] Fly ash and a silicon source are dispersed in an alcohol-water solution, hydrolyzed with acid, and then condensed with alkali to obtain a wet gel. When adding acid for hydrolysis, there are no particular restrictions on the type of acid used; it can be inorganic acids such as sulfuric acid, hydrochloric acid, nitric acid, and phosphoric acid, or organic acids such as oxalic acid, malic acid, and p-toluenesulfonic acid. The pH during hydrolysis is 2.5-4, and the hydrolysis time is 0.5-1 hour. When adding alkali for condensation, there are no particular restrictions on the type of alkali used; it can be ammonia, sodium carbonate, sodium hydroxide, tetramethylammonium hydroxide, potassium hydroxide, etc. The pH during condensation is 9-11, and condensation continues until the solution changes from a flowing liquid to a non-flowing wet gel.

[0028] After aging and displacement of the wet gel, it is immersed in a modification solution for modification, then washed and dried to obtain the final product.

[0029] Wet gel aging can further promote the formation of a three-dimensional Si-O-Si cross-linked network structure and the interaction between the siloxane structure and fly ash particles. Specifically, the aging process can involve sealing the wet gel and placing it in an environment of 60-90℃ for 24-96 hours, such as 60℃×96h, 70℃×72h, 80℃×48h, etc., without any particular restrictions. Displacement involves using organic solvents such as acetone or butyl acetate to displace the alcohol-water solution of the wet gel, preventing the subsequent addition of modifying solutions from becoming ineffective. For example, one displacement method involves three displacements with acetone, as follows: Immerse the aged wet gel in acetone at 5-20 times its volume for 2-12 hours, remove the wet gel, remove the surface solvent, immerse it again in acetone at 5-20 times its volume for 2-12 hours for further displacement, remove the wet gel, remove the surface solvent, immerse it again in acetone at 5-20 times its volume for 2-12 hours for further displacement, remove the wet gel, remove the surface solvent, immerse it again in acetone at 5-20 times its volume for 2-12 hours for further displacement, remove the wet gel, and remove the surface solvent.

[0030] In this application, there are no particular limitations on drying; supercritical fluid drying, freeze-vacuum drying, or atmospheric pressure drying can be used. Conventional methods for preparing silica aerogels often result in low strength in wet silica gels. During atmospheric pressure drying, the rapid solvent evaporation leads to severe capillary action, causing the three-dimensional Si-O-Si crosslinked network structure to shrink and collapse. This application finds that fly ash-modified silica aerogels, possibly due to the high activity of SiO2 and Al2O3 components, can participate in the formation of the three-dimensional Si-O-Si crosslinked network structure, with fly ash particles providing good support. Furthermore, there are strong interactions between fly ash particles, resulting in wet gels with high mechanical strength that can be dried at atmospheric pressure.

[0031] In a preferred embodiment of this application, the weight ratio of fly ash, silicon source, and alcohol-water solution is 0.5-10:1:20-100. When the weight ratio of fly ash to silicon source is too small, the resource utilization of fly ash is not significant, and the characteristics of fly ash cannot be clearly reflected. The supporting effect of fly ash particles on modified silica aerogel is not obvious. When the weight ratio of fly ash to silicon source is too large, too many fly ash particles will destroy the formation of the three-dimensional Si-O-Si cross-linked network structure, resulting in the inability to form a stable fly ash-modified silica aerogel. More preferably, the weight ratio of fly ash to silicon source can be 1-8:1. For example, the weight ratio can be any value among 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, and 8:1.

[0032] Generally, the greater the weight of fly ash, the more alcohol-water solution is required. Therefore, the specific weight ratio of fly ash, silicon source, and alcohol-water solution can be any value among 1:1:25, 3:1:50, 5:1:70, 8:1:100, etc. In this application, the alcohol-water solution can be composed of anhydrous ethanol and water in a volume ratio of 8:2-9:1.

[0033] In a preferred embodiment of this application, the average particle size of the fly ash is 0.5-100 μm. Further, the average particle size of the fly ash is 1-70 μm. If the average particle size of the fly ash is too small, it is difficult to disperse, and its oil absorption is too high, resulting in a high adsorption capacity for silicon source molecules, which is not conducive to the hydrolysis of silicon source molecules and the formation of fly ash-modified silica aerogel. When the average particle size of the fly ash is too large, the fly ash particles occupy too much space, affecting the condensation after hydrolysis of silicon source molecules and hindering the formation of a three-dimensional Si-O-Si cross-linked network structure.

[0034] In a preferred embodiment of this application, the silicon source is selected from one or more combinations of alkyl orthosilicates, water glass, and trialkoxysilane coupling agents. For example, the alkyl orthosilicate can be ethyl orthosilicate, methyl orthosilicate, etc., and the trialkoxysilane coupling agent can be methyltrimethoxysilane, methyltriethoxysilane, 3-aminopropyltrimethoxysilane, etc.

[0035] In a preferred embodiment of this application, the modifying solution is selected from a hexane solution of trimethylchlorosilane with a concentration of 1-100 g / L. Using trimethylchlorosilane as a modifying agent, it reacts with the silanol groups on the three-dimensional Si-O-Si crosslinked network structure, thereby improving the mechanical strength and stability of the wet gel. For example, the concentration of the hexane solution of trimethylchlorosilane can be any value selected from 1 g / L, 10 g / L, 20 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, etc. The modification time of the modification solution can be 12-72 hours. Generally, the higher the concentration of the modification solution, the shorter the modification time can be. For example, using a hexane solution of trimethylchlorosilane with a concentration of 80 g / L as the modification agent, the modification time at room temperature can be 20-24 hours. Using a hexane solution of trimethylchlorosilane with a concentration of 20 g / L as the modification agent, the modification time at room temperature can be 48-50 hours.

[0036] In a preferred embodiment of this application, the modifying solution contains one or more combinations of aminochlorosilanes and aminoalkoxysilanes at a concentration of 1-50 g / L. The presence of aminochlorosilanes and / or aminoalkoxysilanes in the modifying solution can introduce amino organic groups into the interior or surface of the modified silica aerogel. These amino organic groups can improve the compatibility of the modified silica aerogel with polymers and can also chemically react with some polymers or other materials. For example, the concentration of aminochlorosilanes and / or aminoalkoxysilanes in the modifying solution can be any value selected from 1 g / L, 5 g / L, 10 g / L, 15 g / L, 20 g / L, 25 g / L, 30 g / L, 35 g / L, 40 g / L, 45 g / L, 50 g / L, etc. In this application, the aminochlorosilane can be 3-aminopropyldimethylchlorosilane, etc., and the aminoalkoxysilane can be 3-aminopropyldimethylmethoxysilane, etc.

[0037] Therefore, for example, the modification solution of this application can be a hexane solution containing aminochlorosilane and trimethylchlorosilane, wherein the concentration of aminochlorosilane can be 1-50 g / L and the concentration of aminoalkoxysilane can be 1-100 g / L.

[0038] On the other hand, this application also provides a fly ash sound insulation coating composition containing 10-40% by weight of fly ash modified silica aerogel prepared by the preparation method of fly ash modified silica aerogel described in any of the above-mentioned technical solutions. The fly ash sound insulation coating composition of this application contains fly ash modified silica aerogel, which gives the fly ash sound insulation coating composition better sound insulation and heat insulation properties, and has less impact on the mechanical properties of the coating composition. Furthermore, the weight percentage of fly ash modified silica aerogel in the fly ash sound insulation coating composition can be 15-35%, for example, any value selected from 15%, 17%, 20%, 22%, 25%, 27%, 30%, 32%, 35%, etc.

[0039] In this application, the film-forming main material of the fly ash sound insulation coating composition is not particularly limited and can be selected from one or a combination of acrylic resin, modified acrylic resin, polyurethane, modified polyurethane, epoxy resin, modified epoxy resin, polysiloxane, and ethylene-vinyl acetate. For example, the fly ash sound insulation coating composition of this application can also be water-based or water-based, and can be based on waterborne polyurethane or water-based polyurethane, acrylic emulsion, waterborne epoxy resin, polysiloxane, ethylene-vinyl acetate emulsion, etc. The weight percentage of the film-forming main material in the fly ash sound insulation coating can be 10-50%.

[0040] In this application, the above-mentioned fly ash sound insulation coating composition may also contain one or more of the following: solvent, dispersant, wetting agent, leveling agent, defoamer, anti-settling agent, pigment and filler. The solvent can be an organic solvent or water, and its weight percentage in the coating composition can be 20-90%; the dispersant can be a polymeric dispersant, such as a polyacrylic acid dispersant, and its weight percentage in the coating composition can be 0.3-1%; the wetting agent can be a polyether-modified silicone oil wetting agent, and its weight percentage in the coating composition can be 0.3-0.5%; the leveling agent can be an acrylate leveling agent or a polyether-modified silicone oil leveling agent, and its weight percentage in the coating composition can be 0.3-0.8%; the defoamer can be dimethyl silicone oil, and its weight percentage in the coating composition can be 0.5-1%; the anti-settling agent can be fumed silica, organobentonite, attapulgite, etc., and its weight percentage in the coating composition can be 0.5-2%; the pigment can be any, and can be an inorganic pigment or an organic dye, and its weight percentage in the coating composition can be 0.5-5%; the filler can be an organic filler and / or an inorganic filler, excluding silica aerogel or modified silica aerogel, and its weight percentage in the coating composition can be 10-50%.

[0041] Furthermore, this application also provides a fly ash sound insulation coating composition, comprising, by weight, the following raw material components: 100 parts cement, 200-300 parts sand, 0.5-10 parts redispersible latex powder, 0.5-10 parts cellulose ether, and 20-200 parts fly ash modified silica aerogel as described in any of the above technical solutions. The coating composition based on this raw material is essentially a building mortar. Further, the building mortar may also include 0.1-0.3 parts air-entraining agent, 30-100 parts fiber, and 20-60 parts aggregate, etc.

[0042] The technical solution of this application will be described in detail below with reference to embodiments and comparative examples.

[0043] Examples 1-5: Preparation of fly ash modified silica aerogel

[0044] Example 1

[0045] Four parts of fly ash with an average particle size of 15 μm and one part of tetraethyl orthosilicate were added to 60 parts of an alcohol-water solution (composed of anhydrous ethanol and water in a volume ratio of 8:2). The mixture was ultrasonically dispersed evenly, and 1 mol / L sulfuric acid was added to adjust the pH to 3.5. The mixture was stirred and hydrolyzed for 0.5 hours, and then ammonia was added to adjust the pH to 9.5. The mixture was stirred and condensed to form a wet gel.

[0046] After sealing, the wet gel was aged at 70℃ for 72 hours. The aged gel was then immersed in acetone (10 times its volume) for 12 hours for displacement, repeated three times. The displaced gel was then immersed in a 20 g / L hexane solution of trimethylchlorosilane for 48 hours for modification. After removal, it was washed once with anhydrous ethanol and dried under normal pressure to obtain fly ash modified silica aerogel. The normal pressure drying process was as follows: 25℃ for 2 hours, 60℃ in a forced-air drying oven for 2 hours, 90℃ in a forced-air drying oven for 2 hours, and 120℃ in a forced-air drying oven for 1.5 hours.

[0047] Example 2

[0048] The difference between Example 2 and Example 1 is that in Example 1, the fly ash was reduced from 4 parts to 1 part. The remaining steps remained unchanged.

[0049] Example 3

[0050] The difference between Example 3 and Example 1 is that in Example 1, the fly ash was increased from 4 parts to 8 parts, and the alcohol-water solution was increased from 60 parts.

[0051] Adjust the quantity to 100. The remaining steps remain unchanged.

[0052] Example 4

[0053] The difference between Example 4 and Example 1 is that in Example 1, the atmospheric pressure drying was changed to supercritical carbon dioxide drying. The remaining steps remain unchanged.

[0054] Example 5

[0055] The difference between Example 5 and Example 1 is that in Example 1, the hexane solution also contained 10 g / L of 3-aminopropyldimethylchlorosilane. The remaining steps remained unchanged.

[0056] Comparative Example 1

[0057] The difference between Comparative Example 1 and Example 1 is that fly ash was not added in Example 1. The remaining steps remained unchanged.

[0058] After drying at normal pressure, the silica aerogel shrinks significantly.

[0059] Comparative Example 2

[0060] The difference between Comparative Example 2 and Example 4 is that fly ash was not added in Example 4. The remaining steps remained unchanged.

[0061] The performance comparison of fly ash modified silica aerogels in Examples 1-5 and silica aerogels in Comparative Example 2 is shown in Table 1 below.

[0062] Table 1

[0063]

[0064]

[0065] As shown in Table 1, the fly ash modified silica aerogel of this application has a certain reduction in BET specific surface area and porosity, possibly due to the fly ash filling of the silica aerogel. However, it still has a high BET specific surface area and porosity, and the compressive strength is significantly improved.

[0066] Example 6

[0067] The sound insulation coating composition is formulated as follows, 100% by weight: 40% aqueous epoxy resin emulsion (60% solid content, epoxy equivalent 290 g / eq), 25% fly ash modified silica aerogel of Example 1, 0.6% organosilicon modified polyether leveling agent, 1% dimethyl silicone oil defoamer, 1% organobentonite, 25% talc powder with an average particle size of 2 μm, and the balance being water.

[0068] Fly ash modified silica aerogel, talc powder and water were added to waterborne epoxy resin emulsion and stirred at 3000 rpm for 15 minutes. Then, organosilicon modified polyether silicone oil leveling agent, dimethyl silicone oil defoamer and organobentonite were added in sequence and stirred at 300 rpm for 10 minutes to obtain sound insulation coating.

[0069] Example 7

[0070] The difference between Example 7 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted from 25% to 15%. The remaining steps remained unchanged.

[0071] Example 8

[0072] The difference between Example 8 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted from 25% to 35%. The remaining steps remained unchanged.

[0073] Example 9

[0074] The difference between Example 9 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted to an equal weight percentage of the fly ash modified silica aerogel of Example 2. The remaining steps remained unchanged.

[0075] Example 10

[0076] The difference between Example 10 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted to an equal weight percentage of the fly ash modified silica aerogel of Example 3. The remaining steps remained unchanged.

[0077] Example 11

[0078] The difference between Example 11 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 is adjusted to an equal weight percentage of the fly ash modified silica aerogel of Example 5. The remaining steps remain unchanged.

[0079] Comparative Example 3

[0080] The difference between Comparative Example 3 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted to an equal weight percentage of the silica aerogel of Comparative Example 2. The remaining steps remained unchanged.

[0081] Comparative Example 4

[0082] The difference between Comparative Example 4 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted to an equal weight percentage of the fly ash in Example 1. The remaining steps remained unchanged.

[0083] Comparative Example 5

[0084] The difference between Comparative Example 5 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted to be a combination of fly ash from Example 1 and silica aerogel from Comparative Example 2 in a weight ratio of 6:1 with equal weight percentages. The remaining steps remained unchanged.

[0085] Comparative Example 6

[0086] The difference between Comparative Example 6 and Example 6 is that in Example 6, the fly ash modified silica aerogel of Example 1 was adjusted to be a combination of fly ash from Example 1 and silica aerogel from Comparative Example 2 in a weight ratio of 2:1 with equal weight percentages. The remaining steps remained unchanged.

[0087] Example 12

[0088] The fly ash sound insulation coating composition (building mortar) comprises the following raw material components: 100 parts cement, 220 parts sand, 5 parts redispersible latex powder, 3 parts cellulose ether and 80 parts fly ash modified silica aerogel of Example 1.

[0089] Example 13

[0090] The difference between Example 13 and Example 12 is that in Example 12, the amount of fly ash modified silica aerogel was increased from 80 parts to 150 parts. The remaining steps remained unchanged.

[0091] Comparative Example 7

[0092] The difference between Comparative Example 7 and Example 13 is that in Example 13, the fly ash modified silica aerogel was replaced with hollow glass microspheres with an average particle size of 5 μm of equal weight.

[0093] Before use, the sound-insulating coating compositions of Examples 6-11 and Comparative Examples 3-6 were mixed evenly with curing agent N-62A at a weight ratio of 10:3. The curing conditions were 25±2℃ for 48 hours.

[0094] Before use, 80 parts of water were added to the sound-insulating coating compositions of Examples 12, 13, and Comparative Example 7, and the mixtures were stirred until homogeneous. The curing conditions were 25±2℃ for 24 hours.

[0095] Sound insulation performance is tested according to GB / T 14369-2011. The higher the sound insulation coefficient, the better the sound insulation effect.

[0096] Tensile strength was tested in accordance with GB / T 16777-2008.

[0097] The results are shown in Table 2 below.

[0098] Table 2

[0099]

[0100] As shown in Table 2 above, the sound-absorbing coating containing fly ash-modified silica aerogel exhibits better sound absorption performance, and its sound absorption effect is higher than that of silica aerogel alone or fly ash alone. This may be related to the fact that the structure of fly ash-modified silica aerogel combines the characteristics of both fly ash and silica aerogel. Furthermore, the sound-absorbing coating containing fly ash-modified silica aerogel has better tensile strength than fly ash alone, silica aerogel alone, or a combination of fly ash and silica aerogel. This indicates that the fly ash-modified silica aerogel in this application is not simply a structural combination or patchwork of fly ash and silica aerogel.

[0101] Example 14

[0102] The sound insulation coating is formulated as follows, 100% by weight: 35% styrene-acrylic emulsion (40% solid content), 30% fly ash modified silica aerogel of Example 1, 0.5% organosilicon modified polyether leveling agent, 0.8% dimethyl silicone oil defoamer, 1.3% organobentonite, 10 parts of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, and the balance being water.

[0103] Fly ash modified silica aerogel and water were added to styrene-acrylic emulsion and dispersed at high speed of 3000 rpm for 12 min. Then, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, organosilicon modified polyether silicone oil leveling agent, dimethyl silicone oil defoamer and organobentonite were added in sequence and dispersed at 300 rpm for 10 min to obtain sound insulation coating.

[0104] The coating was applied to the stainless steel plate and heated at 80℃ for 30 minutes to form a film. The sound insulation coefficient was measured to be 80.4, and the impact strength was measured to be 175 N / m according to GB / T 1732-2020.

[0105] Comparative Example 8

[0106] The difference between Comparative Example 8 and Example 14 is that in Example 14, the fly ash modified silica aerogel of Example 1 was adjusted to an equal weight percentage of the fly ash in Example 1. The remaining steps remained unchanged.

[0107] According to the test method in Example 14, the sound insulation coefficient was measured to be 70.6 and the impact strength was 124 N / m.

[0108] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing fly ash modified silica aerogel, characterized in that, Includes the following steps: Fly ash and silicon source are dispersed in an alcohol-water solution, acid is added to adjust the pH to 2.5-4 for hydrolysis, and then alkali is added to adjust the pH to 9-11 for condensation to obtain a wet gel. The wet gel is aged, replaced, and then immersed in a modification solution for modification, washed, and dried to obtain the final product. The weight ratio of the fly ash, the silicon source, and the alcohol-water solution is 0.5-10:1:20-100; The average particle size of the fly ash is 0.5-100 μm; The silicon source is selected from one or more combinations of alkyl orthosilicate, water glass and trialkoxysilane coupling agent; The modifying solution is selected from a hexane solution of trimethylchlorosilane with a concentration of 1-100 g / L; the modifying solution also contains one or more combinations of aminochlorosilane and aminoalkoxysilane with a concentration of 1-50 g / L. The replacement involves using an organic solvent to replace the alcohol-water solution of the wet gel.

2. The method for preparing fly ash modified silica aerogel according to claim 1, characterized in that, The alcohol-water solution is composed of anhydrous ethanol and water in a volume ratio of 8:2 to 9:

1.

3. A fly ash sound insulation coating composition, characterized in that, The fly ash modified silica aerogel prepared by the method of any one of claims 1-2, containing 10-40% by weight of fly ash modified silica aerogel.

4. The fly ash sound insulation coating composition according to claim 3, characterized in that, The film-forming main material of the fly ash sound insulation coating composition is selected from one or more combinations of acrylic resin, modified acrylic resin, polyurethane, modified polyurethane, epoxy resin, modified epoxy resin, polysiloxane and ethylene-vinyl acetate.

5. A fly ash sound insulation coating composition, characterized in that, By weight, the raw material components include: 100 parts cement, 200-300 parts sand, 0.5-10 parts redispersible latex powder, 0.5-10 parts cellulose ether and 20-200 parts fly ash modified silica aerogel according to any one of claims 1-2.

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