Silicon-based aerogel thermal insulation material

Abstract

The invention discloses a silicon-based aerogel thermal insulation material, and relates to the technical field of architectural coatings. The silicon-based aerogel thermal insulation material is prepared from the following raw materials in parts by weight: 20 to 30 parts of silicon-based aerogel powder, 5 to 10 parts of loofah sponge composite fiber, 30 to 45 parts of waterborne fluorine-containing acrylic emulsion, 15 to 25 parts of modified nano particles, 1 to 2 parts of nano cerium dioxide, 75 to 85 parts of deionized water, 8 to 12 parts of binder, 11 to 17 parts of dispersant, 1 to 3 parts of initiator, 5 to 8 parts of coalescing agent and 1 to 2 parts of defoaming agent. 1-2 parts of a thickening agent; the silicon-based aerogel thermal insulation material prepared by the invention can be cured at normal temperature, has good thermal insulation property, high thermal stability, stain resistance and aging resistance, and has 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 its 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 to some extent meet the market demand, but have the shortcomings of flammability, aging, moisture absorption, poor environmental protection, etc., 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, 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 coating in the prior art often only improves its mechanical and thermal properties, or reduces the production cost of aerogel, such as CN113292894B and CN109517520B. These silicon-based aerogel coatings usually add ultraviolet absorbers and light stabilizers to improve their anti-aging performance. These small molecule anti-aging agents are prone to migrate and precipitate after long-term use, which reduces the anti-aging performance 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 filled with thermal performance, so how to improve the stain resistance and aging resistance of the silicon-based aerogel coating while ensuring 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, which solves the following technical problems: 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.

[0005] The purpose of the present application can be achieved by the following technical solutions: A silicon-based aerogel thermal insulation material, comprising the following raw materials by weight: 20-30 parts of silicon-based aerogel powder, 5-10 parts of silk gourd 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 dispersant, 1-3 parts of initiator, 5-8 parts of film-forming aid, 1-2 parts of defoaming agent, 1-2 parts of thickening agent.

[0006] As a further embodiment of the present invention: the preparation method of the aqueous fluorinated acrylic emulsion comprises the following steps: A1. Place alkylphenol polyoxyethylene ether, sodium lauryl sulfate, methyl methacrylate, butyl acrylate, ammonium persulfate, and water in a reaction flask, stir, and heat at a heating rate of 1.5°C / min to 60°C and hold for 1 hour. A2. Mix methyl methacrylate, butyl acrylate, and the fluorinated acrylic block copolymer, add them to a dropping funnel, and add them dropwise to the reaction flask over a period of 2-3 hours. Raise the temperature until the solution turns blue, then maintain the temperature for 2 hours. After cooling, disperse the mixture using a high-speed disperser until the fineness is ≤25 μm to obtain a water-based fluorinated acrylic emulsion.

[0007] As a further embodiment of the present invention: the mass ratio of alkylphenol polyoxyethylene ether, sodium lauryl sulfate, methyl methacrylate, 5-10g butyl acrylate, ammonium persulfate, and water in A1 is 0.5-1g: 0.2-0.5g: 5-10g: 0.1-0.2g: 70g; The added mass ratio of methyl methacrylate, butyl acrylate and fluorinated acrylate block copolymer in A2 is 5-10g:5-10g:5-10g.

[0008] As a further solution of the present invention: the preparation method of the loofah composite fiber comprises the following steps: B1. treating the loofah residue with alkali at 85° C. for 1-2 hours, drying the residue to a moisture content of less than 3%, and crushing the residue into small pieces of 2 mm×2 mm×2 mm to obtain loofah fibers; B2. Blend loofah fiber, ferric chloride hexahydrate, and deionized water, add pyrrole, stir for 4 hours, and dry to a moisture content of less than 3% to obtain loofah composite fiber.

[0009] As a further solution of the present invention: the alkali used in the alkali treatment process in B1 is a mixed aqueous solution of 5 wt % NaOH and 5 wt % H 2 O 2 .

[0010] As a further embodiment of the present invention, the addition ratio of the loofah fiber, water, ferric chloride hexahydrate, and pyrrole in B2 is 400 g: 400-500 mL: 5.4-6.7 g: 2.7-3.4 g.

[0011] As a further embodiment of the present invention, the method for preparing the modified nanoparticles comprises the following steps: C1, add deionized water, NaOH aqueous solution, cetyltrimethylammonium bromide, 35-45℃ stirring 30min-1h, increase the temperature to 80-90℃, add tetraethyl orthosilicate and stir for 2-3h, cool to room temperature, centrifuge, wash, dry, in the muffle furnace with the heating rate of 1.5℃ / min to 550℃ calcination 4h to obtain mesoporous silica nanoparticles; C2, add mesoporous silica nanoparticles into anhydrous ethanol, ultrasonic dispersion for 10-15min, add N,N'-diphenyl-p-phenylenediamine and continue ultrasonic dispersion for 10-20min, filter, wash, dry to obtain the modified nanoparticles.

[0012] As a further scheme of the application: the addition mass ratio of anhydrous ethanol, deionized water, NaOH aqueous solution, cetyltrimethylammonium bromide, 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%; The addition 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.

[0013] As a further scheme of the application: the dispersant is gas silicon dispersant HFS and polyacrylate ammonium salt, and the addition mass ratio is 10-15:1-2; The binder is organic silicone resin adhesive; The initiator is dibenzoyl peroxide; The film-forming aid is any one or several of propylene glycol phenyl ether, propylene glycol butyl ether, alcohol ester twelve; The defoaming agent is polyether modified silicone oil; The thickening agent is non-ionic polyurethane associated thickening agent HEUR.

[0014] As a further scheme of the application: the preparation method of the silicon-based aerogel thermal insulation material comprises the following steps: S1: mixing water-based fluorine-containing acrylic emulsion, nano cerium dioxide and deionized water to obtain fluorocarbon resin mixed emulsion by stirring for 1-2h; S2: mixing silicon-based aerogel powder, luffa complex fiber, modified fluorocarbon resin and initiator to obtain silicon-based aerogel mixed emulsion; S3: mixing silicon-based aerogel mixed emulsion, deionized water, binder, dispersant, film-forming aid and thickening agent, adding them into a ball mill for ball milling for 1-2h, and then adding a defoaming agent for ball milling for 1h to obtain a silicon-based aerogel thermal insulation material.

[0015] The application has the following beneficial effects: (1) The present invention utilizes polypyrrole-modified loofah fibers to obtain loofah composite fibers. Loofah fibers are three-dimensional porous mesh structures formed by interweaving multiple layers of filamentous fibers. They are lightweight, have a high specific surface area, and have excellent energy absorption properties. 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 coupling pyrrole molecules at the α-α position and has a conjugated large π bond structure. Polypyrrole-modified loofah fibers can improve the aging resistance, thermal insulation, and thermal stability of the material.

[0016] (2) The present invention utilizes nano-cerium dioxide to modify fluorocarbon resin. The fluorine atoms in the fluorocarbon resin molecules have large electronegativity, small radius, short FC bond length, large bond energy, low polarizability, good stability to light, heat, chemical properties, etc., and good protective effect. Therefore, the fluorocarbon resin coating has excellent performance, with high adhesion, solvent resistance, self-cleaning, and high weather resistance. Due to the 4f and 5d orbital electrons of cerium, it can be used in Ce 3+ and Ce 4+ Flexible switching between the two, during the process of oxygen storage and release 3+ / Ce 4+ The cycle promotes the dynamic generation of oxygen vacancies, thereby efficiently participating in the redox reaction. In addition, due to the quantum size effect and surface defects, nano-cerium dioxide further enhances its electron transfer ability, resulting in nano-cerium dioxide modified fluorocarbon resin improving the aging resistance of the coating.

[0017] (3) The present invention adds mesoporous silica nanoparticles adsorbing bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate. Bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate contains hindered amine groups and achieves antioxidant properties through a three-level protection mechanism: chain termination reaction - capturing peroxyl 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 DESCRIPTION

[0018] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0019] Example 1 The preparation method of the aqueous fluorinated acrylic emulsion comprises the following steps: A1. Place 0.75 g of alkylphenol polyoxyethylene ether, 0.35 g of sodium lauryl sulfate, 7.5 g of methyl methacrylate, 7.5 g of butyl acrylate, 0.15 g of ammonium persulfate, and 70 g of water into a reaction flask, stir, and heat at a heating rate of 1.5 °C / min to 60 °C and hold for 1 h. A2. Mix 7.5 g of methyl methacrylate, 7.5 g of butyl acrylate, and 7.5 g of a fluorinated acrylic block copolymer. Add the mixture to a dropping funnel and add the mixture dropwise to the reaction flask over a period of 2.5 hours. Heat the mixture until the solution turns blue and maintain the temperature for 2 hours. After cooling, disperse the mixture using a high-speed disperser until the solution has a fineness of 25 μm or less to obtain a water-based fluorinated acrylic emulsion.

[0020] Example 2 The preparation method of loofah composite fiber comprises the following steps: B1. The loofah residue was treated with an alkali solution of 5 wt % NaOH and 5 wt % H2O2 at 85°C for 1 hour, dried to a moisture content of less than 3%, and crushed into small pieces of 2 mm × 2 mm × 2 mm to obtain loofah fibers; B2. Blend 400 g of loofah fiber, 6.0 g of ferric chloride hexahydrate, and 450 ml of deionized water, add 3.1 g of pyrrole, stir for 4 h, and dry to a moisture content of less than 3% to obtain loofah composite fiber.

[0021] Example 3 The preparation method of modified nanoparticles comprises the following steps: C1. Take 22 g of anhydrous ethanol, add 200 g of deionized water, 1.5 g of 8 wt% NaOH aqueous solution, and 0.5 g of hexadecyltrimethylammonium bromide, stir at 40 ° C for 1 h, heat to 85 ° C, add 2 g of tetraethyl orthosilicate, stir for 2.5 h, cool to room temperature, centrifuge, wash, dry, and heat to 550 ° C in a muffle furnace at a heating rate of 1.5 ° C / min and calcine for 4 h to obtain mesoporous silica nanoparticles; C2. Add 2.5 g of mesoporous silica nanoparticles to 50 mL of anhydrous ethanol, ultrasonically disperse for 13 min, add 0.3 g of bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate and continue ultrasonically dispersing for 15 min, filter, wash, and dry to obtain the modified nanoparticles.

[0022] Example 4 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 20 parts of silicon-based aerogel powder, 5 parts of loofah composite fiber, 30 parts of aqueous fluorinated acrylic emulsion, 5 parts of modified nanoparticles, 1 part of nano-cerium dioxide, 75 parts of deionized water, 8 parts of binder, 11 parts of dispersant, 1 part of initiator, 5 parts of film-forming aid, 1 part of defoamer, and 1 part of 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 comprises the following steps: S1: 30 g of the aqueous fluorinated acrylic emulsion of Example 1, 1 g of nano-cerium dioxide, and 25 g of deionized water were mixed and stirred for 1 h to obtain a fluorocarbon resin mixed emulsion; S2: 20 g of silicon-based aerogel powder, 5 g of the loofah composite fiber of Example 1, 5 g of the modified nanoparticles of Example 1, a fluorocarbon resin mixed emulsion, and 1 g of dibenzoyl peroxide were mixed to obtain a silicon-based aerogel mixed emulsion; S3: The silica-based aerogel mixed emulsion, 50 g deionized water, 8 g silicone resin adhesive, 10 g silica dispersant HFS, 1 g polyacrylate ammonium salt, 5 g propylene glycol butyl ether, and 1 g nonionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 1 g polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silica-based aerogel thermal insulation material.

[0023] Example 5 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 25 parts of silicon-based aerogel powder, 8 parts of loofah composite fiber, 38 parts of aqueous fluorinated acrylic emulsion, 8 parts of modified nanoparticles, 1.5 parts of nano-cerium dioxide, 80 parts of deionized water, 10 parts of binder, 14 parts of dispersant, 2 parts of initiator, 6.5 parts of film-forming aid, 1.5 parts of defoamer, and 1.5 parts of thickener. The aqueous fluorinated acrylic emulsion is prepared by the method of 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 comprises the following steps: S1: 38 g of the aqueous fluorinated acrylic emulsion of Example 2, 1.5 g of nano-cerium dioxide, and 30 g of deionized water were mixed and stirred for 1.5 h to obtain a fluorocarbon resin mixed emulsion; S2: 25 g of silicon-based aerogel powder, 8 g of the loofah composite fiber of Example 2, 8 g of the modified nanoparticles of Example 2, a fluorocarbon resin mixed emulsion, and 2 g of dibenzoyl peroxide were mixed to obtain a silicon-based aerogel mixed emulsion; S3: The silicon-based aerogel mixed emulsion, 50 g deionized water, 10 g silicone resin adhesive, 12.5 g silicon dispersant HFS, 1.5 g polyacrylate ammonium salt, 6.5 g propylene glycol butyl ether, and 1.5 g nonionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 1.5 g polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silicon-based aerogel thermal insulation material.

[0024] Example 6 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 30 parts of silicon-based aerogel powder, 10 parts of loofah composite fiber, 45 parts of aqueous fluorinated acrylic emulsion, 10 parts of modified nanoparticles, 2 parts of nano-cerium dioxide, 85 parts of deionized water, 12 parts of binder, 17 parts of dispersant, 3 parts of initiator, 8 parts of film-forming aid, 2 parts of defoamer, and 2 parts of thickener. The aqueous fluorinated acrylic emulsion is prepared by the method of 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 comprises the following steps: S1: 45 g of the aqueous fluorinated acrylic emulsion of Example 3, 2 g of nano-cerium dioxide, and 35 g of deionized water were mixed and stirred for 2 h to obtain a fluorocarbon resin mixed emulsion; S2: 30 g of silicon-based aerogel powder, 10 g of the loofah composite fiber of Example 3, 10 g of the modified nanoparticles of Example 3, a fluorocarbon resin mixed emulsion, and 3 g of dibenzoyl peroxide were mixed to obtain a silicon-based aerogel mixed emulsion; S3: The silica-based aerogel mixed emulsion, 50 g of deionized water, 12 g of silicone resin adhesive, 15 g of silicone dispersant HFS, 2 g of polyacrylate ammonium salt, 8 g of propylene glycol butyl ether, and 2 g of non-ionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 2 g of polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silica-based aerogel thermal insulation material.

[0025] Example 7 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 25 parts of silicon-based aerogel powder, 8 parts of loofah composite fiber, 38 parts of aqueous fluorinated acrylic emulsion, 8 parts of modified nanoparticles, 1.5 parts of nano-cerium dioxide, 80 parts of deionized water, 10 parts of binder, 14 parts of dispersant, 2 parts of initiator, 6.5 parts of film-forming aid, 1.5 parts of defoaming agent, and 1.5 parts of thickener. The aqueous fluorinated acrylic emulsion is prepared by the method of 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 comprises the following steps: S1: 45 g of the aqueous fluorinated acrylic emulsion of Example 2, 2 g of nano-cerium dioxide, and 35 g of deionized water were mixed and stirred for 2 h to obtain a fluorocarbon resin mixed emulsion; S2: 30 g of silicon-based aerogel powder, 10 g of the loofah composite fiber of Example 2, 8 g of the modified nanoparticles of Example 2, a fluorocarbon resin mixed emulsion, and 3 g of dibenzoyl peroxide were mixed to obtain a silicon-based aerogel mixed emulsion; S3: The silica-based aerogel mixed emulsion, 50 g of deionized water, 12 g of silicone resin adhesive, 15 g of silicone dispersant HFS, 2 g of polyacrylate ammonium salt, 8 g of propylene glycol butyl ether, and 2 g of non-ionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 2 g of polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silica-based aerogel thermal insulation material.

[0026] Comparative Example 1 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 25 parts of silicon-based aerogel powder, 8 parts of loofah composite fiber, 38 parts of aqueous fluorinated acrylic emulsion, 8 parts of modified nanoparticles, 1.5 parts of nano-cerium dioxide, 80 parts of deionized water, 10 parts of binder, 14 parts of dispersant, 2 parts of initiator, 6.5 parts of film-forming aid, 1.5 parts of defoaming agent, and 1.5 parts of 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 comprises the following steps: S1: 38 g of the aqueous fluorinated acrylic emulsion of Example 2, 1.5 g of nano-cerium dioxide, and 30 g of deionized water were mixed and stirred for 1.5 h to obtain a fluorocarbon resin mixed emulsion; S2: 25 g of silicon-based aerogel powder, 8 g of modified nanoparticles of Example 2, fluorocarbon resin mixed emulsion, and 2 g of dibenzoyl peroxide were mixed to obtain a silicon-based aerogel mixed emulsion; S3: The silicon-based aerogel mixed emulsion, 50 g deionized water, 10 g silicone resin adhesive, 12.5 g silicon dispersant HFS, 1.5 g polyacrylate ammonium salt, 6.5 g propylene glycol butyl ether, and 1.5 g nonionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 1.5 g polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silicon-based aerogel thermal insulation material.

[0027] Comparative Example 2 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 25 parts of silicon-based aerogel powder, 8 parts of loofah composite fiber, 38 parts of aqueous fluorinated acrylic emulsion, 8 parts of modified nanoparticles, 1.5 parts of nano-cerium dioxide, 80 parts of deionized water, 10 parts of binder, 14 parts of dispersant, 2 parts of initiator, 6.5 parts of film-forming aid, 1.5 parts of defoaming agent, and 1.5 parts of 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 comprises the following steps: S1: 25 g of silica-based aerogel powder, 8 g of loofah composite fiber of Example 2, 8 g of modified nanoparticles of Example 2, and 2 g of dibenzoyl peroxide were mixed to obtain a silica-based aerogel mixed emulsion; S2: The silica-based aerogel mixed emulsion, 50 g deionized water, 10 g silicone resin adhesive, 12.5 g silica dispersant HFS, 1.5 g polyacrylate ammonium salt, 6.5 g propylene glycol butyl ether, and 1.5 g nonionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 1.5 g polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silica-based aerogel thermal insulation material.

[0028] Comparative Example 3 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 25 parts of silicon-based aerogel powder, 8 parts of loofah composite fiber, 38 parts of aqueous fluorinated acrylic emulsion, 8 parts of modified nanoparticles, 1.5 parts of nano-cerium dioxide, 80 parts of deionized water, 10 parts of binder, 14 parts of dispersant, 2 parts of initiator, 6.5 parts of film-forming aid, 1.5 parts of defoaming agent, and 1.5 parts of 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 comprises the following steps: S1: 38 g of the aqueous fluorinated acrylic emulsion of Example 2 and 30 g of deionized water were mixed and dispersed uniformly to obtain a fluorocarbon resin; S2: 25 g of silica-based aerogel powder, 8 g of loofah composite fiber, 8 g of modified nanoparticles of Example 2, fluorocarbon resin, and 2 g of dibenzoyl peroxide were mixed to obtain a silica-based aerogel mixed emulsion; S3: The silicon-based aerogel mixed emulsion, 50 g deionized water, 10 g silicone resin adhesive, 12.5 g silicon dispersant HFS, 1.5 g polyacrylate ammonium salt, 6.5 g propylene glycol butyl ether, and 1.5 g nonionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 1.5 g polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silicon-based aerogel thermal insulation material.

[0029] Comparative Example 4 A silicon-based aerogel thermal insulation material comprises the following raw materials in parts by weight: 25 parts of silicon-based aerogel powder, 8 parts of loofah composite fiber, 38 parts of aqueous fluorinated acrylic emulsion, 8 parts of modified nanoparticles, 1.5 parts of nano-cerium dioxide, 80 parts of deionized water, 10 parts of binder, 14 parts of dispersant, 2 parts of initiator, 6.5 parts of film-forming aid, 1.5 parts of defoaming agent, and 1.5 parts of 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 comprises the following steps: S1: 38 g of the fluorinated acrylic emulsion of Example 2, 1.5 g of nano-cerium dioxide, and 30 g of deionized water were mixed and stirred for 1.5 h to obtain a fluorocarbon resin mixed emulsion; S2: 25 g of silicon-based aerogel powder, 8 g of the loofah composite fiber from Example 2, the fluorocarbon resin mixed emulsion, and 2 g of dibenzoyl peroxide were mixed to obtain a silicon-based aerogel mixed emulsion; S3: The silicon-based aerogel mixed emulsion, 50 g deionized water, 10 g silicone resin adhesive, 12.5 g silicon dispersant HFS, 1.5 g polyacrylate ammonium salt, 6.5 g propylene glycol butyl ether, and 1.5 g nonionic polyurethane associative thickener HEUR were mixed together, added to a ball mill and ball-milled for 1 h, and then 1.5 g polyether-modified silicone oil was added and ball-milled for 1 h to obtain a silicon-based aerogel thermal insulation material.

[0030] Performance testing: Examples 4-7 and Comparative Examples 1-4 were respectively coated on a 15 cm×7.5 cm×1 cm steel plate substrate to obtain samples, and various performance tests were performed on the samples.

[0031] 1. Thermal properties: Characterized by thermal conductivity and heat resistance: (1) Thermal conductivity: According to GB / T 10294-2008 "Determination of Steady-State Thermal Resistance and Related Properties of Insulating Materials - Guarded Hot Plate Method", the sample is placed in a double-specimen guarded hot plate device. The device consists of two almost identical samples with a heating unit sandwiched between them. The heat flow is transferred from the heating unit to the cooling units on both sides through the two specimens. The heating unit and the cooling unit have a metering unit with insulation and auxiliary protection units on the edge of the device. When the metering unit reaches a stable heat transfer state, the data is measured and the thermal conductivity λ is calculated:

[0032] Where, φ is heat flux, unit is W; A is heat transfer area, unit is m 2 ; dt / dx is the temperature gradient (unit temperature difference divided by thickness); the results are shown in Table 2; (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 taken out and cooled to room temperature to check whether the coating film was cracked or peeling. The results are shown in Table 1.

[0033] Table 1 Statistical table of adhesion and surface drying time of samples obtained from Examples 4-7 and Comparative Examples 1-4

[0034] As can be seen from Table 1, Examples 4-7 have excellent thermal properties; Comparative Example 1 has the worst thermal insulation and high temperature resistance due to the lack of loofah composite fiber; Comparative Example 2 lacks fluorocarbon resin, which increases the thermal conductivity of the material and reduces the thermal insulation performance; Comparative Example 4 lacks modified nanoparticles, resulting in a decrease in high temperature resistance.

[0035] Stain resistance: The stain resistance of the specimens was tested according to GB / T 9780-2013, Test Method for Stain Resistance of Architectural Paint Coatings. A suspension of the pollution source was evenly applied to the specimen surface using a soft brush, first horizontally and then vertically. The specimen was allowed to stand for 2 hours, then rinsed. The specimen was then color-compared with a basic gray color chart and graded. A grade of 1 or less was considered acceptable. The results are shown in Table 2.

[0036] 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 coatings were artificially weathered using xenon arc light filtered through a daylight filter. The test was conducted until the coating showed signs of chalking. The time was recorded. The results are shown in Table 2.

[0037] Table 2 Statistical table of stain resistance and aging resistance of samples obtained from Examples 4-7 and Comparative Examples 1-4

[0038] As can be seen from Table 2, Examples 4-7 and Comparative Example 1 have ultra-high aging resistance because they contain modified fluorocarbon resin and modified nanoparticles, but Comparative Example 1 lacks loofah composite fiber, resulting in slightly worse stain resistance than Examples 4-7, Comparative Example 3 and Comparative Example 4; Comparative Example 3 has worse aging resistance than Examples 4-7 and Comparative Example 1 because the fluorocarbon resin is not modified with nano-cerium dioxide; Comparative Example 4 has a significantly decreased aging resistance due to the lack of modified nanoparticles; Comparative Example 2 and Comparative Example 3 have far worse stain resistance and aging resistance than other examples and comparative examples due to the lack of fluorocarbon resin components.

[0039] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and should not be considered to limit the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of 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 of silicon-based aerogel powder, 5-10 parts of loofah composite fibers, 30-45 parts of aqueous fluorine-containing acrylic emulsion, 5-10 parts of modified nanoparticles, 1-2 parts of nano-cerium dioxide, 75-85 parts of deionized water, 8-12 parts of binder, 11-17 parts of dispersant, 1-3 parts of initiator, 5-8 parts of film-forming aid, 1-2 parts of defoaming agent, and 1-2 parts of thickener.

2. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that: The preparation method of the aqueous fluorinated acrylic emulsion comprises the following steps: A1. Place alkylphenol polyoxyethylene ether, sodium lauryl sulfate, methyl methacrylate, butyl acrylate, ammonium persulfate, and water in a reaction flask, stir, and heat at a heating rate of 1.5°C / min to 60°C and hold for 1 hour. A2. Mix methyl methacrylate, butyl acrylate, and the fluorinated acrylic block copolymer, add them to a dropping funnel, and add them dropwise to the reaction flask over a period of 2-3 hours. Raise the temperature until the solution turns blue, then maintain the temperature for 2 hours. After cooling, disperse the mixture using a high-speed disperser until the fineness is ≤25 μm to obtain a water-based 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 lauryl sulfate, methyl methacrylate, 5-10g butyl acrylate, ammonium persulfate, and water in A1 is 0.5-1g: 0.2-0.5g: 5-10g: 0.1-0.2g: 70g; The added 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 preparation method of the loofah composite fiber comprises the following steps: B1. treating the loofah residue with alkali at 85° C. for 1-2 hours, drying the residue to a moisture content of less than 3%, and crushing the residue into small pieces of 2 mm×2 mm×2 mm to obtain loofah fibers; B2. Blend loofah fiber, ferric chloride hexahydrate, and deionized water, add pyrrole, stir for 4 hours, and dry to a moisture content of less than 3% to obtain loofah composite fiber.

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

6. The silicon-based aerogel thermal insulation material according to claim 4, 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.

7. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that: The preparation method of the modified nanoparticles comprises the following steps: C1. Take anhydrous ethanol, add deionized water, NaOH aqueous solution, and cetyltrimethylammonium bromide, stir at 35-45°C for 30 min-1 h, heat to 80-90°C, add tetraethyl orthosilicate, and stir for 2-3 h. Cool to room temperature, centrifuge, wash, and dry. Heat to 550°C in a muffle furnace at a heating rate of 1.5°C / min and calcine for 4 h to obtain mesoporous silica nanoparticles; C2. Add the mesoporous silica nanoparticles to anhydrous ethanol, ultrasonically disperse for 10-15 minutes, add bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate and continue ultrasonically dispersing for 10-20 minutes, filter, wash and dry to obtain the modified nanoparticles.

8. The silicon-based aerogel thermal insulation material according to claim 7, characterized in that: The added mass ratio of anhydrous ethanol, deionized water, NaOH aqueous solution, hexadecyltrimethylammonium bromide, and tetraethyl orthosilicate in C1 is 20-24 g: 200 g: 1-2 g: 0.3-0.6 g: 1.5-2.5 g, and the concentration of NaOH aqueous solution is 8 wt %; The addition ratio of mesoporous silica nanoparticles, anhydrous ethanol, and bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate in C2 is 2-3 g:50 mL:0.1-0.3 g.

9. The silicon-based aerogel thermal insulation material according to claim 1, characterized in that: The dispersant is a gas silica dispersant HFS and polyacrylate ammonium salt, and the addition mass ratio is 10-15:1-2; The binder is a silicone resin adhesive; The initiator is dibenzoyl peroxide; The film-forming aid is any one or more of propylene glycol phenyl ether, propylene glycol butyl ether, and alcohol ester twelve; The defoaming agent is polyether modified silicone oil; The thickener is a nonionic polyurethane associative thickener HEUR.

10. 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 comprises the following steps: S1: Mixing aqueous fluorinated acrylic emulsion, nano-cerium dioxide, and deionized water, and stirring for 1-2 hours to obtain a fluorocarbon resin mixed emulsion; S2: mixing silica-based aerogel powder, loofah composite fiber, modified fluorocarbon resin, and initiator to obtain silica-based aerogel mixed emulsion; S3: The silicon-based aerogel mixed emulsion, deionized water, binder, dispersant, film-forming aid, and thickener are mixed together, added to a ball mill and ball-milled for 1-2 hours, and then a defoaming agent is added and ball-milled for 1 hour to obtain a silicon-based aerogel thermal insulation material.

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