Silica-based aerogel thermal insulation

Abstract

The application discloses a silicon-based aerogel thermal insulation material and relates to the technical field of building coating. The silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 20-30 parts of silicon-based aerogel powder, 5-10 parts of luffa complex fiber, 30-45 parts of water-based fluorine-containing acrylic emulsion, 15-25 parts of modified nano-particles, 1-2 parts of nano cerium dioxide, 75-85 parts of deionized water, 8-12 parts of a binder, 11-17 parts of a dispersing agent, 1-3 parts of an initiator, 5-8 parts of a film-forming aid, 1-2 parts of a defoaming agent and 1-2 parts of a thickening agent. The silicon-based aerogel thermal insulation material prepared by the application can be cured at room temperature, has good thermal insulation, high thermal stability, dirt resistance, aging resistance and self-cleaning property.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building coatings, and particularly relates to a silicon-based aerogel thermal insulation material. BACKGROUND

[0002] Thermal insulation materials play a vital role in modern industry and construction, and their main function is to protect equipment and buildings from external temperatures by reducing heat conduction and radiation, saving energy and improving the use environment. Traditional thermal insulation materials such as mineral wool, foam glass and polyurethane, although they meet market demand to some extent, have shortcomings such as flammability, aging, moisture absorption and poor environmental protection, which limit their application scenarios. Silicon-based aerogel thermal insulation material is a new type of material with excellent thermal insulation performance, mainly based on silicon dioxide, prepared by sol-gel method, with a highly porous network structure, and its thermal conductivity is extremely low, usually between 0.02-0.03 W / (m·K), which has a significant advantage over ordinary thermal insulation materials, and also has the characteristics of high temperature resistance and light weight.

[0003] However, the silicon-based aerogel coatings in the prior art often only improve their mechanical and thermal properties, or reduce the production cost of aerogels, such as CN113292894B and CN109517520B. These silicon-based aerogel coatings usually add ultraviolet absorbers and light stabilizers to improve their anti-aging properties. These small molecule anti-aging agents are prone to migrate and precipitate after long-term use, which reduces the anti-aging properties of the coating and cannot meet the comprehensive requirements of high stain resistance and high aging resistance of the coating in the field of building materials. At the same time, the silicon-based aerogel composite material often has a porous structure that is filled and causes a decrease in thermal performance, so how to improve the stain resistance and aging resistance of the silicon-based aerogel coating while maintaining its high thermal performance is a current technical difficulty. SUMMARY

[0004] The purpose of the present application is to provide a silicon-based aerogel thermal insulation material that solves the following technical problems:

[0005] The silicon-based aerogel coating in the prior art cannot balance the thermal stability, high temperature resistance, stain resistance and aging resistance of the coating, and cannot meet the high performance requirements of the coating in the field of building materials.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A kind of silica aerogel thermal insulation material, including the following weight parts of raw materials: 20-30 parts of silica aerogel powder, 5-10 parts of luffa complex fiber, 30-45 parts of water-based fluorine-containing acrylic emulsion, 5-10 parts of modified nanoparticles, 1-2 parts of nanometer cerium dioxide, 75-85 parts of deionized water, 8-12 parts of binder, 11-17 parts of dispersing agent, 1-3 parts of initiator, 5-8 parts of film forming aid, 1-2 parts of defoaming agent, 1-2 parts of thickening agent.

[0008] As a further scheme of the application: the preparation method of the water-based fluorine-containing acrylic emulsion comprises the following steps:

[0009] A1, alkyl phenol polyoxyethylene ether, sodium dodecyl sulfate, methyl methacrylate, butyl acrylate, ammonium persulfate, water are put into reaction bottle and stirred to warm up to 60 DEG C at a heating rate of 1.5 DEG C / min, and kept constant for 1h;

[0010] A2, methyl methacrylate, butyl acrylate, fluorine-containing acrylic ester block copolymer are mixed and then added to the dropping funnel, and added dropwise in the reaction bottle at a dropwise time of 2-3h. After the solution turns blue, it is kept constant for 2h. After cooling, it is dispersed to a fineness of less than or equal to 25 μm using a high-speed dispersion machine to obtain a water-based fluorine-containing acrylic emulsion.

[0011] As a further scheme of the application: the addition mass ratio of alkyl phenol polyoxyethylene ether, sodium dodecyl sulfate, methyl methacrylate, butyl acrylate, ammonium persulfate and water in A1 is 0.75g:0.35g:7.5g:7.5g:0.15g:70g;

[0012] The addition mass ratio of methyl methacrylate, butyl acrylate and fluorine-containing acrylic ester block copolymer in A2 is 5-10g:5-10g:5-10g.

[0013] As a further scheme of the application: the preparation method of the luffa complex fiber comprises the following steps:

[0014] B1, after alkali treatment of luffa residue at 85 DEG C for 1-2h, it is dried to a water content of less than or equal to 3%, broken into small pieces of 2mmx2mmx2mm, and luffa fiber is obtained;

[0015] B2, luffa fiber, ferric chloride hexahydrate and deionized water are blended, pyrrole is added and stirred for 4h, and then dried to a water content of less than or equal to 3% to obtain luffa complex fiber.

[0016] As a further scheme of the application: the alkali used in the alkali treatment process in B1 is a mixed aqueous solution of 5wt% NaOH and 5wt% H2O2.

[0017] As a further scheme of the present application: the adding ratio of silk gourd fiber, water, hexahydrate ferric chloride, and pyrrole in B2 is 400 g: 400-500 mL: 5.4-6.7 g: 2.7-3.4 g.

[0018] As a further scheme of the present application: the preparation method of the modified nanoparticles comprises the following steps:

[0019] C1, take anhydrous ethanol, add deionized water, NaOH aqueous solution, cetyltrimethylammonium bromide, stir at 35-45℃ for 30min-1h, warm up to 80-90℃, add tetraethyl orthosilicate and stir for 2-3h, cool to room temperature, centrifuge, wash, dry, and calcine in a muffle furnace at a heating rate of 1.5℃ / min to 550℃ for 4h to obtain mesoporous silica nanoparticles;

[0020] C2, add mesoporous silica nanoparticles to anhydrous ethanol, ultrasonic dispersion for 10-15min, add N,N'-diphenyl-p-phenylenediamine and continue ultrasonic dispersion for 10-20min, filter, wash, and dry to obtain the modified nanoparticles.

[0021] As a further scheme of the present application: the adding mass ratio of anhydrous ethanol, deionized water, NaOH aqueous solution, cetyltrimethylammonium bromide, and tetraethyl orthosilicate in C1 is 20-24g: 200g: 1-2g: 0.3-0.6g: 1.5-2.5g, and the concentration of NaOH aqueous solution is 8wt%;

[0022] The adding ratio of mesoporous silica nanoparticles, anhydrous ethanol, and bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate in C2 is 2-3g: 50mL: 0.1-0.3g.

[0023] As a further scheme of the present application: the dispersant is gas silicon dispersant HFS and polyacrylic acid ammonium salt, and the adding mass ratio is 10-15: 1-2;

[0024] The binder is an organic silicone resin adhesive;

[0025] The initiator is dibenzoyl peroxide;

[0026] The film-forming aid is any one or several of propylene glycol phenyl ether, propylene glycol butyl ether, and alcohol ester twelve;

[0027] The defoaming agent is polyether modified silicone oil;

[0028] The thickening agent is non-ionic polyurethane associated thickening agent HEUR.

[0029] As a further scheme of the present application: the preparation method of the silicon-based aerogel thermal insulation material comprises the following steps:

[0030] S1: Mix water-based fluorinated acrylic emulsion, nano-cerium dioxide, and deionized water, and stir for 1-2 hours to obtain a fluorocarbon resin mixed emulsion.

[0031] S2: Silicon-based aerogel powder, loofah composite fiber, modified fluorocarbon resin and initiator are mixed to obtain a silicone-based aerogel mixed emulsion.

[0032] S3: Mix the silicone aerogel emulsion, deionized water, binder, dispersant, film-forming aid, and thickener together, add them to a ball mill and ball mill for 1-2 hours, then add defoamer and ball mill for 1 hour to obtain silicone aerogel thermal insulation material.

[0033] The beneficial effects of this invention are:

[0034] (1) This invention utilizes polypyrrole-modified loofah fibers to obtain loofah composite fibers. Loofah fibers are three-dimensional porous network structures formed by the interweaving of multiple layers of filamentous fibers. They have lightweight, high specific surface area and excellent energy absorption characteristics. The abundant cellulose and hemicellulose in the fiber bundles provide natural polar groups for interfacial bonding, which is conducive to forming physical anchoring or chemical bonding with the polymer matrix. Polypyrrole is a polymer formed by the coupling of pyrrole molecules at the α-α position. It has a conjugated large π bond structure. Polypyrrole-modified loofah fibers can improve the aging resistance, heat insulation and thermal stability of the material.

[0035] (2) This invention utilizes nano-cerium dioxide to modify fluorocarbon resin. Fluorine atoms in fluorocarbon resin molecules have high electronegativity and small radius, short FC bond length and high bond energy, and low polarizability, exhibiting good stability against light, heat, and chemical properties, thus providing excellent protection. Therefore, fluorocarbon resin coatings possess outstanding performance, exhibiting high adhesion, solvent resistance, self-cleaning properties, and high weather resistance. The 4f and 5d orbital electrons of cerium allow it to... 3+ and Ce 4+ Flexible switching between these modes during oxygen storage and release, Ce 3+ / Ce 4+ Cyclic processes promote the dynamic generation of oxygen vacancies, enabling them to participate efficiently in redox reactions. Furthermore, due to quantum size effects and surface defects, nano-cerium dioxide further enhances its electron transport capabilities, resulting in improved aging resistance of nano-cerium dioxide-modified fluorocarbon resin coatings.

[0036] (3) In this invention, mesoporous silica nanoparticles adsorbing bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate are added. Bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate contains hindered amine groups and achieves anti-oxidation through a three-level protection mechanism: chain termination reaction - capturing peroxide radicals (ROO·) to interrupt the chain reaction, hydrogen transfer mechanism - providing active hydrogen atoms to reduce free radicals, and metal passivation - complexing copper / iron ions to inhibit catalytic oxidation, which can significantly improve the thermal stability and aging resistance of the coating. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1: The preparation method of the aqueous fluorinated acrylic emulsion includes the following steps:

[0039] A1. Place 0.75g alkylphenol polyoxyethylene ether, 0.35g sodium dodecyl sulfate, 7.5g methyl methacrylate, 7.5g butyl acrylate, 0.15g ammonium persulfate, and 70g water into a reaction flask and stir and heat. Heat to 60℃ at a rate of 1.5℃ / min and hold at that temperature for 1 hour.

[0040] A2. Mix 7.5g of methyl methacrylate, 7.5g of butyl acrylate, and 7.5g of fluorinated acrylate block copolymer and add the mixture to a dropping funnel, adding it dropwise over 2.5 hours to a reaction flask. Heat the solution until it turns blue and then maintain the temperature for 2 hours. After cooling, disperse the mixture using a high-speed disperser to a fineness of ≤25μm to obtain an aqueous fluorinated acrylic emulsion.

[0041] Example 2: The preparation method of loofah composite fiber includes the following steps:

[0042] B1. The loofah residue was treated with a mixed aqueous solution of 5wt% NaOH and 5wt% H2O2 at 85℃ for 1 hour, then dried to a moisture content of less than 3%, and broken into small pieces of 2mm×2mm×2mm to obtain loofah fiber.

[0043] B2. Mix 400g of loofah fiber, 6.0g of ferric chloride hexahydrate, and 450ml of deionized water, add 3.1g of pyrrole and stir for 4 hours. Dry until the moisture content is below 3% to obtain loofah composite fiber.

[0044] Example 3: The preparation method of modified nanoparticles includes the following steps:

[0045] C1. Take 22g of anhydrous ethanol, add 200g of deionized water, 1.5g of 8wt% NaOH aqueous solution, and 0.5g of cetyltrimethylammonium bromide. Stir at 40℃ for 1h, raise the temperature to 85℃, add 2g of tetraethyl orthosilicate, stir for 2.5h, cool to room temperature, centrifuge, wash, dry, and calcine in a muffle furnace at a heating rate of 1.5℃ / min to 550℃ for 4h to obtain mesoporous silica nanoparticles.

[0046] C2. Add 2.5g of mesoporous silica nanoparticles to 50mL of anhydrous ethanol and sonicate for 13min. Add 0.3g of bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and continue sonication for 15min. Filter, wash and dry to obtain the modified nanoparticles.

[0047] Example 4: A silicon-based aerogel thermal insulation material, comprising the following raw materials in parts by weight: 20 parts silicon-based aerogel powder, 5 parts loofah composite fiber, 30 parts aqueous fluorinated acrylic emulsion, 5 parts modified nanoparticles, 1 part nano-cerium dioxide, 75 parts deionized water, 8 parts binder, 11 parts dispersant, 1 part initiator, 5 parts film-forming aid, 1 part defoamer, and 1 part thickener. The aqueous fluorinated acrylic emulsion is prepared by the method in Example 1, the loofah composite fiber is prepared by the method in Example 2, and the modified nanoparticles are prepared by the method in Example 3. The preparation method of the silicon-based aerogel thermal insulation material includes the following steps:

[0048] S1: Mix 30g of aqueous fluorinated acrylic emulsion from Example 1, 1g of nano-cerium dioxide, and 25g of deionized water, and stir for 1 hour to obtain a fluorocarbon resin mixed emulsion.

[0049] S2: 20g of silicone aerogel powder, 5g of loofah composite fiber from Example 2, 5g of modified nanoparticles from Example 3, fluorocarbon resin mixed emulsion, and 1g of benzoyl peroxide were mixed to obtain a silicone aerogel mixed emulsion.

[0050] S3: Mix silicone-based aerogel emulsion, 50g deionized water, 8g silicone resin adhesive, 10g silicone dispersant HFS, 1g ammonium polyacrylate, 5g propylene glycol butyl ether, and 1g nonionic polyurethane associative thickener HEUR, add to a ball mill and ball mill for 1 hour, then add 1g polyether-modified silicone oil and ball mill for 1 hour to obtain silicone-based aerogel thermal insulation material.

[0051] Example 5: A silicon-based aerogel thermal insulation material, comprising the following raw materials in parts by weight: 25 parts silicon-based aerogel powder, 8 parts loofah composite fiber, 38 parts aqueous fluorinated acrylic emulsion, 8 parts modified nanoparticles, 1.5 parts nano-cerium dioxide, 80 parts deionized water, 10 parts binder, 14 parts dispersant, 2 parts initiator, 6.5 parts film-forming aid, 1.5 parts defoamer, and 1.5 parts thickener. The aqueous fluorinated acrylic emulsion is prepared by the method in Example 1, the loofah composite fiber is prepared by Example 2, and the modified nanoparticles are prepared by Example 3. The preparation method of the silicon-based aerogel thermal insulation material includes the following steps:

[0052] S1: Mix 38g of aqueous fluorinated acrylic emulsion from Example 1, 1.5g of nano-cerium dioxide, and 30g of deionized water, and stir for 1.5h to obtain a fluorocarbon resin mixed emulsion.

[0053] S2: 25g of silicone aerogel powder, 8g of loofah composite fiber from Example 2, 8g of modified nanoparticles from Example 3, fluorocarbon resin mixed emulsion, and 2g of benzoyl peroxide were mixed to obtain a silicone aerogel mixed emulsion.

[0054] S3: Mix silicone-based aerogel emulsion, 50g deionized water, 10g silicone resin adhesive, 12.5g silicone dispersant HFS, 1.5g ammonium polyacrylate, 6.5g propylene glycol butyl ether, and 1.5g nonionic polyurethane associative thickener HEUR, add them to a ball mill and ball mill for 1 hour, then add 1.5g polyether-modified silicone oil and ball mill for another hour to obtain silicone-based aerogel thermal insulation material.

[0055] Example 6 A silicon-based aerogel thermal insulation material, comprising the following raw materials in parts by weight: 30 parts silicon-based aerogel powder, 10 parts loofah composite fiber, 45 parts aqueous fluorinated acrylic emulsion, 10 parts modified nanoparticles, 2 parts nano-cerium dioxide, 85 parts deionized water, 12 parts binder, 17 parts dispersant, 3 parts initiator, 8 parts film-forming aid, 2 parts defoamer, and 2 parts thickener. The aqueous fluorinated acrylic emulsion is prepared by the method in Example 1, the loofah composite fiber is prepared by the method in Example 2, and the modified nanoparticles are prepared by the method in Example 3. The preparation method of the silicon-based aerogel thermal insulation material includes the following steps:

[0056] S1: Mix 45g of aqueous fluorinated acrylic emulsion from Example 1, 2g of nano-cerium dioxide, and 35g of deionized water, and stir for 2 hours to obtain a fluorocarbon resin mixed emulsion.

[0057] S2: 30g of silicone aerogel powder, 10g of loofah composite fiber from Example 2, 10g of modified nanoparticles from Example 3, fluorocarbon resin mixed emulsion, and 3g of benzoyl peroxide were mixed to obtain a silicone aerogel mixed emulsion.

[0058] S3: Mix silicone-based aerogel emulsion, 50g deionized water, 12g silicone resin adhesive, 15g silicone dispersant HFS, 2g ammonium polyacrylate, 8g propylene glycol butyl ether, and 2g nonionic polyurethane associative thickener HEUR, add to a ball mill and ball mill for 1 hour, then add 2g polyether-modified silicone oil and ball mill for 1 hour to obtain silicone-based aerogel thermal insulation material.

[0059] Example 7 A silicon-based aerogel thermal insulation material, comprising the following raw materials in parts by weight: 25 parts silicon-based aerogel powder, 8 parts loofah composite fiber, 38 parts aqueous fluorinated acrylic emulsion, 8 parts modified nanoparticles, 1.5 parts nano-cerium dioxide, 80 parts deionized water, 10 parts binder, 14 parts dispersant, 2 parts initiator, 6.5 parts film-forming aid, 1.5 parts defoamer, and 1.5 parts thickener. The aqueous fluorinated acrylic emulsion is prepared by the method in Example 1, the loofah composite fiber is prepared by Example 2, and the modified nanoparticles are prepared by Example 3. The preparation method of the silicon-based aerogel thermal insulation material includes the following steps:

[0060] S1: Mix 45g of aqueous fluorinated acrylic emulsion from Example 1, 2g of nano-cerium dioxide, and 35g of deionized water, and stir for 2 hours to obtain a fluorocarbon resin mixed emulsion.

[0061] S2: 30g of silicone aerogel powder, 10g of loofah composite fiber from Example 2, 8g of modified nanoparticles from Example 3, fluorocarbon resin mixed emulsion, and 3g of benzoyl peroxide were mixed to obtain a silicone aerogel mixed emulsion.

[0062] S3: Mix silicone-based aerogel emulsion, 50g deionized water, 12g silicone resin adhesive, 15g silicone dispersant HFS, 2g ammonium polyacrylate, 8g propylene glycol butyl ether, and 2g nonionic polyurethane associative thickener HEUR, add to a ball mill and ball mill for 1 hour, then add 2g polyether-modified silicone oil and ball mill for 1 hour to obtain silicone-based aerogel thermal insulation material.

[0063] Comparative Example 1: A silicone-based aerogel insulation material, comprising the following raw materials in parts by weight: 25 parts silicone-based aerogel powder, 38 parts aqueous fluorinated acrylic emulsion, 8 parts modified nanoparticles, 1.5 parts nano-cerium dioxide, 80 parts deionized water, 10 parts binder, 14 parts dispersant, 2 parts initiator, 6.5 parts film-forming aid, 1.5 parts defoamer, and 1.5 parts thickener. The aqueous fluorinated acrylic emulsion is prepared by the method in Example 1, and the modified nanoparticles are prepared by the method in Example 3. The preparation method of the silicone-based aerogel insulation material includes the following steps:

[0064] S1: Mix 38g of aqueous fluorinated acrylic emulsion, 1.5g of nano-cerium dioxide, and 30g of deionized water, and stir for 1.5h to obtain a fluorocarbon resin mixed emulsion.

[0065] S2: 25g of silicone aerogel powder, 8g of modified nanoparticles, fluorocarbon resin mixed emulsion, and 2g of benzoyl peroxide are mixed to obtain silicone aerogel mixed emulsion.

[0066] S3: Mix silicone-based aerogel emulsion, 50g deionized water, 10g silicone resin adhesive, 12.5g silicone dispersant HFS, 1.5g ammonium polyacrylate, 6.5g propylene glycol butyl ether, and 1.5g nonionic polyurethane associative thickener HEUR, add them to a ball mill and ball mill for 1 hour, then add 1.5g polyether-modified silicone oil and ball mill for another hour to obtain silicone-based aerogel thermal insulation material.

[0067] Comparative Example 2: A silicon-based aerogel thermal insulation material, comprising the following raw materials in parts by weight: 25 parts silicon-based aerogel powder, 8 parts loofah composite fiber, 8 parts modified nanoparticles, 1.5 parts nano-cerium dioxide, 80 parts deionized water, 10 parts binder, 14 parts dispersant, 2 parts initiator, 6.5 parts film-forming aid, 1.5 parts defoamer, and 1.5 parts thickener. The loofah composite fiber was prepared in Example 2, and the modified nanoparticles were prepared in Example 3. The preparation method of the silicon-based aerogel thermal insulation material includes the following steps:

[0068] S1: 25g of silicone aerogel powder, 8g of loofah composite fiber, 8g of modified nanoparticles and 2g of benzoyl peroxide are mixed to obtain a silicone aerogel mixed emulsion.

[0069] S2: Mix silicone-based aerogel emulsion, 80g deionized water, 10g silicone resin adhesive, 12.5g silicone dispersant HFS, 1.5g ammonium polyacrylate, 6.5g propylene glycol butyl ether, and 1.5g nonionic polyurethane associative thickener HEUR, add them to a ball mill and ball mill for 1 hour, then add 1.5g polyether-modified silicone oil and ball mill for another hour to obtain silicone-based aerogel thermal insulation material.

[0070] Comparative Example 3: A silicone-based aerogel insulation material, comprising the following raw materials in parts by weight: 25 parts silicone-based aerogel powder, 8 parts loofah composite fiber, 38 parts aqueous fluorinated acrylic emulsion, 8 parts modified nanoparticles, 80 parts deionized water, 10 parts binder, 14 parts dispersant, 2 parts initiator, 6.5 parts film-forming aid, 1.5 parts defoamer, and 1.5 parts thickener. The aqueous fluorinated acrylic emulsion was prepared by the method in Example 1, the loofah composite fiber was prepared by Example 2, and the modified nanoparticles were prepared by Example 3. The preparation method of the silicone-based aerogel insulation material includes the following steps:

[0071] S1: Mix 38g of aqueous fluorinated acrylic emulsion and 30g of deionized water and disperse them evenly to obtain fluorocarbon resin.

[0072] S2: 25g of silicone aerogel powder, 8g of loofah composite fiber, 8g of modified nanoparticles, fluorocarbon resin and 2g of benzoyl peroxide are mixed to obtain a silicone aerogel mixed emulsion.

[0073] S3: Mix silicone-based aerogel emulsion, 50g deionized water, 10g silicone resin adhesive, 12.5g silicone dispersant HFS, 1.5g ammonium polyacrylate, 6.5g propylene glycol butyl ether, and 1.5g nonionic polyurethane associative thickener HEUR, add them to a ball mill and ball mill for 1 hour, then add 1.5g polyether-modified silicone oil and ball mill for another hour to obtain silicone-based aerogel thermal insulation material.

[0074] Comparative Example 4: A silicone-based aerogel insulation material, comprising the following raw materials in parts by weight: 25 parts silicone-based aerogel powder, 8 parts loofah composite fiber, 38 parts aqueous fluorinated acrylic emulsion, 1.5 parts nano-cerium dioxide, 80 parts deionized water, 10 parts binder, 14 parts dispersant, 2 parts initiator, 6.5 parts film-forming aid, 1.5 parts defoamer, and 1.5 parts thickener. The aqueous fluorinated acrylic emulsion was prepared by the method in Example 1, and the loofah composite fiber was prepared by the method in Example 2. The preparation method of the silicone-based aerogel insulation material includes the following steps:

[0075] S1: Mix 38g of fluorinated acrylic emulsion, 1.5g of nano-cerium dioxide, and 30g of deionized water, and stir for 1.5h to obtain a fluorocarbon resin mixed emulsion.

[0076] S2: 25g of silicone aerogel powder, 8g of loofah composite fiber, fluorocarbon resin mixed emulsion, and 2g of benzoyl peroxide are mixed to obtain silicone aerogel mixed emulsion.

[0077] S3: Mix silicone-based aerogel emulsion, 50g deionized water, 10g silicone resin adhesive, 12.5g silicone dispersant HFS, 1.5g ammonium polyacrylate, 6.5g propylene glycol butyl ether, and 1.5g nonionic polyurethane associative thickener HEUR, add them to a ball mill and ball mill for 1 hour, then add 1.5g polyether-modified silicone oil and ball mill for another hour to obtain silicone-based aerogel thermal insulation material.

[0078] Performance testing:

[0079] Examples 4-7 and Comparative Examples 1-4 were coated onto a 15cm×7.5cm×1cm steel plate substrate to obtain samples, and various performance tests were performed on the samples.

[0080] 1. Thermal properties: Characterized by thermal conductivity and heat resistance:

[0081] (1) Thermal conductivity: According to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulation Materials - Protective Hot Plate Method", the sample is placed in a double-sample protective hot plate device. The device consists of two almost identical samples sandwiching a heating unit. The heat flow is transferred from the heating unit to the cooling units on both sides through the samples on both sides. The heating unit and the cooling unit are connected by a metering unit. The device edge has insulation and auxiliary protective units. After the metering unit reaches a stable heat transfer state, the measured data are used to calculate the thermal conductivity λ:

[0082] In the formula, φ is the heat flow rate in W; A is the heat transfer area in m². 2 dt / dx is the temperature gradient (unit temperature difference divided by thickness); the results are shown in Table 2.

[0083] (2) High temperature resistance: According to GB / T 1735-2009 "Determination of heat resistance of paints and varnishes", the sample was placed in a high temperature furnace and baked at 600℃ for 24 hours. The sample was then taken out and cooled to room temperature. The coating was checked for cracking and peeling. The results are shown in Table 1.

[0084] Table 1. Statistical table of adhesion and surface drying time of samples prepared in Examples 4-7 and Comparative Examples 1-4.

[0085]

[0086] As shown in Table 1, Examples 4-7 exhibited excellent thermal properties; Comparative Example 1 had the worst thermal insulation and high-temperature resistance due to the lack of loofah composite fiber; Comparative Example 2 lacked fluorocarbon resin, which increased the thermal conductivity of the material and decreased its thermal insulation performance; Comparative Example 4 lacked modified nanoparticles, which led to a decrease in high-temperature resistance.

[0087] 2. Stain resistance: The stain resistance of the sample was tested according to GB / T 9780-2013 "Test method for stain resistance of architectural coatings". The pollution source suspension was evenly brushed onto the sample surface first horizontally and then vertically with a soft brush. After 2 hours, the sample was rinsed and the sample was compared with the basic gray color card to evaluate the grade. Grade 1 or less was qualified. The results are shown in Table 2.

[0088] 3. Aging resistance: The aging resistance of the samples was tested according to GB / T 1865-2009 "Paints and varnishes - Artificial weathering and artificial radiation exposure - filtered xenon arc radiation". The sample coating was subjected to artificial weathering using xenon arc lamps filtered through a daylight filter until chalking of the coating appeared. The time was recorded and the results are shown in Table 2.

[0089] Table 2. Statistical table of stain resistance and aging resistance data of samples prepared in Examples 4-7 and Comparative Examples 1-4.

[0090]

[0091] As shown in Table 2, Examples 4-7 and Comparative Example 1 exhibit ultra-high aging resistance due to the presence of modified fluorocarbon resin and modified nanoparticles. However, Comparative Example 1, lacking loofah composite fiber, has slightly lower stain resistance than Examples 4-7, Comparative Example 3, and Comparative Example 4. Comparative Example 3, due to the absence of nano-cerium dioxide modification in the fluorocarbon resin, has lower aging resistance than Examples 4-7 and Comparative Example 1. Comparative Example 4 shows a significant decrease in aging resistance due to the lack of modified nanoparticles. Comparative Example 2, lacking fluorocarbon resin components, has significantly lower stain resistance and aging resistance than the other examples and comparative examples.

[0092] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A silicon-based aerogel thermal insulation material, characterized in that, The silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 20-30 parts silicon-based aerogel powder, 5-10 parts loofah composite fiber, 30-45 parts water-based fluorinated acrylic emulsion, 5-10 parts modified nanoparticles, 1-2 parts nano cerium dioxide, 75-85 parts deionized water, 8-12 parts binder, 11-17 parts dispersant, 1-3 parts initiator, 5-8 parts film-forming aid, 1-2 parts defoamer, and 1-2 parts thickener; The preparation method of the loofah composite fiber includes the following steps: B1. After treating the loofah residue with alkali at 85℃ for 1-2 hours, dry it to a moisture content of less than 3%, and break it into small pieces of 2mm×2mm×2mm to obtain loofah fiber. B2. Mix loofah fiber, ferric chloride hexahydrate, and deionized water, add pyrrole and stir for 4 hours, then dry to a moisture content of less than 3% to obtain loofah composite fiber. The method for preparing the modified nanoparticles includes the following steps: C1. Take anhydrous ethanol, add deionized water, NaOH aqueous solution, and hexadecyltrimethylammonium bromide, stir at 35-45℃ for 30 min-1 h, raise the temperature to 80-90℃ and add tetraethyl orthosilicate, stir for 2-3 h, cool to room temperature, centrifuge, wash, dry, and calcine in a muffle furnace at a heating rate of 1.5℃ / min to 550℃ for 4 h to obtain mesoporous silica nanoparticles; C2. Add mesoporous silica nanoparticles to anhydrous ethanol and ultrasonically disperse for 10-15 min. Add bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and continue ultrasonic dispersion for 10-20 min. Filter, wash, and dry to obtain the modified nanoparticles.

2. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that, The preparation method of the aqueous fluorinated acrylic emulsion includes the following steps: A1. Place alkylphenol polyoxyethylene ether, sodium dodecyl sulfate, methyl methacrylate, butyl acrylate, ammonium persulfate, and water into a reaction flask, stir and heat, and heat to 60℃ at a rate of 1.5℃ / min and hold at that temperature for 1 hour. A2. Mix methyl methacrylate, butyl acrylate, and fluorinated acrylate block copolymer and add them to a dropping funnel. Add the mixture to a reaction flask over a dropping time of 2-3 hours. Heat the solution until it turns blue and then keep it at that temperature for 2 hours. After cooling, disperse the mixture with a high-speed disperser until the fineness is less than or equal to 25 μm to obtain an aqueous fluorinated acrylic emulsion.

3. The silicon-based aerogel thermal insulation material according to claim 2, characterized in that, The mass ratio of alkylphenol polyoxyethylene ether, sodium dodecyl sulfate, methyl methacrylate, butyl acrylate, ammonium persulfate, and water in A1 is 0.75g:0.35g:7.5g:7.5g:0.15g:70g; The mass ratio of methyl methacrylate, butyl acrylate, and fluorinated acrylate block copolymer in A2 is 5-10g: 5-10g: 5-10g.

4. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that, The alkali used in the B1 alkaline treatment process is a mixed aqueous solution of 5wt% NaOH and 5wt% H2O2.

5. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that, The addition ratio of loofah fiber, water, ferric chloride hexahydrate, and pyrrole in B2 is 400g: 400-500mL: 5.4-6.7g: 2.7-3.4g.

6. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that, In C1, the mass ratio of anhydrous ethanol, deionized water, NaOH aqueous solution, hexadecyltrimethylammonium bromide, and tetraethyl orthosilicate is 20-24g:200g:1-2g:0.3-0.6g:1.5-2.5g, and the concentration of NaOH aqueous solution is 8wt%. The addition ratio of C2 mesoporous silica nanoparticles, anhydrous ethanol, and bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate is 2-3g: 50mL: 0.1-0.3g.

7. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that, The dispersant is HFS, a gaseous silica dispersant, and ammonium polyacrylate, with an addition mass ratio of 10-15:1-2. The adhesive is an organosilicon resin adhesive; The initiator is benzoyl peroxide; The film-forming aid is any one or more of propylene glycol phenyl ether, propylene glycol butyl ether, and alcohol ester dodecyl; The defoamer is polyether-modified silicone oil; The thickener is a nonionic polyurethane associative thickener, HEUR.

8. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that, The preparation method of the silicon-based aerogel thermal insulation material includes the following steps: S1: Mix water-based fluorinated acrylic emulsion, nano-cerium dioxide, and deionized water, and stir for 1-2 hours to obtain a fluorocarbon resin mixed emulsion. S2: Silicon-based aerogel powder, loofah composite fiber, modified fluorocarbon resin and initiator are mixed to obtain a silicone-based aerogel mixed emulsion. S3: Mix the silicone aerogel emulsion, deionized water, binder, dispersant, film-forming aid, and thickener together, add them to a ball mill and ball mill for 1-2 hours, then add defoamer and ball mill for 1 hour to obtain silicone aerogel thermal insulation material.

Images