Aerogel fireproof coating and preparation method thereof

Abstract

The present application relates to the technical field of fireproof coating, in particular to an aerogel fireproof coating and a preparation method thereof. In order to improve the dispersibility of the aerogel powder in the resin and the weather resistance of the resin itself, a branched modified epoxy resin is prepared and added as a modified material in the aerogel coating, and silicon and fluorine elements are introduced therein, which can greatly improve the resistance of the epoxy resin to ultraviolet rays and improve the corrosion of the resin to the external acid-base environment, thereby improving the service life of the resin coating. The fluorenone structure has rigidity and can be used as the rigid core of the hyperbranched structure. The carbonyl group of the fluorenone can undergo dehydration, dehydrogenation and decarboxylation with the hydroxyl group and ether bond of the epoxy chain segment at high temperature, promote the rapid crosslinking of the molecular chain and the transformation to the graphitized aromatic ring structure, and form a continuous and dense solid carbon layer, further insulating the heat transfer.

Description

Technical Field

[0001] This invention relates to the field of fire-retardant coating technology, specifically to an aerogel fire-retardant coating and its preparation method. Background Technology

[0002] With the continuous advancement of urbanization in my country, the construction industry has become a crucial sector concerning economic development and public safety. Steel structures, as a mainstream building structure, have broad application prospects. However, at temperatures between 250℃ and 300℃, steel experiences a decrease in impact toughness, and a significant reduction in yield strength, tensile strength, and modulus of elasticity, leading to a rapid loss of structural load-bearing capacity and posing serious safety hazards. In actual fires, the flame temperature of hydrocarbon fuels can reach over 1050℃. Under such extreme temperatures, steel structures will rapidly undergo plastic deformation and localized damage, ultimately leading to overall collapse and causing severe secondary disasters.

[0003] Aerogel materials, as lightweight solid materials with nanoporous silica as the framework and air as the main medium, exhibit extremely low density and thermal conductivity, showing potential for application in fire-retardant coatings. However, their nanoparticles are prone to agglomeration, making uniform dispersion difficult in resin-based coatings; simultaneously, the resin coating itself faces durability challenges in outdoor environments. Therefore, improving the dispersion stability of aerogels in coatings and enhancing the environmental resistance of the coatings has become a key issue in promoting the application of this technology in practical engineering. Summary of the Invention

[0004] The purpose of this invention is to provide an aerogel fire-retardant coating and its preparation method, so as to solve the problems of aerogel dispersibility and the environmental tolerance of resin coatings.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a method for preparing an aerogel fire-retardant coating, comprising the following steps:

[0007] S1. Mix 9-fluorenone-2,7-dicarboxylic acid with a reaction solvent, add pentaerythritol and p-toluenesulfonic acid, heat under a nitrogen atmosphere, and after the reaction is complete, evaporate by rotary evaporation to remove excess reaction solvent to obtain a polyhydroxy branched intermediate.

[0008] S2. After mixing the polyhydroxy branched intermediate with DMF evenly, triethylamine and hexafluoroglutaric acid are added, the mixture is stirred and mixed evenly, heated to react, and then dried by rotary evaporation to obtain the terminal carboxyl branched intermediate.

[0009] S3. After mixing the terminal carboxyl branched intermediate with DMF, 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is added to it. After mixing evenly and heating to react, excess solvent is removed by rotary evaporation. After washing and purification, branched modified epoxy resin is obtained.

[0010] S4. After uniformly mixing aerogel particles, titanium dioxide, reinforcing fibers, ammonium polyphosphate and silane coupling agent, add branched modified epoxy resin, stir and mix thoroughly, then add epoxy resin 601 and n-butanol, mix thoroughly, add curing agent, mix thoroughly, and obtain aerogel fireproof coating.

[0011] Furthermore, in step S1, the mass ratio of 9-fluorenone-2,7-dicarboxylic acid, pentaerythritol, and p-toluenesulfonic acid is 1:(1~1.1):(0.03~0.05).

[0012] The reaction solvent is a mixture of DMF and xylene, wherein the mass ratio of DMF to xylene is 1:(3~5).

[0013] Furthermore, in step S1, during the heating reaction, the temperature is raised to 135~140℃, and the reaction is stirred for 4~5 hours, while the water generated during the reaction is continuously removed.

[0014] Furthermore, in step S2, the mass ratio of the polyhydroxy branched intermediate, triethylamine, and hexafluoroglutaric acid is 1:(0.03~0.04):(1.9~2.05).

[0015] Furthermore, in step S2, after the polyhydroxy branched intermediate is mixed with DMF, the reaction system is cooled to 20-40°C, and then triethylamine and hexafluoroglutaric acid are added to it.

[0016] During the heating reaction, the temperature is increased to 75-80℃ at a rate of 4-8℃ / h, and then the reaction is stirred at a constant temperature for 3-5 hours.

[0017] Furthermore, in step S3, the mass ratio of the terminal carboxyl branched intermediate to 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:(1~1.1).

[0018] Furthermore, in step S3, during the heating reaction, the temperature is raised to 80~85℃, and the reaction is stirred for 3~5 hours;

[0019] During washing and purification, deionized water is added to the reaction system after rotary evaporation, stirred and allowed to stand, the organic phase is separated, washed again with anhydrous ethanol, the lower aqueous phase is separated, and the remaining organic phase is rotary evaporated to remove excess ethanol and water, thus completing the purification.

[0020] Furthermore, in step S4, the mass ratio of aerogel particles, titanium dioxide, reinforcing fiber, ammonium polyphosphate, silane coupling agent, branched modified epoxy resin, epoxy resin 601, n-butanol, and curing agent is (5~10.5):(8~12):(3~7):(7~12):(0.3~1):(12~24):(40~65):(32~60):(15~20).

[0021] Furthermore, in step S4, the reinforcing fiber is glass fiber; and the silane coupling agent is KH550 or KH560.

[0022] Secondly, the present invention also provides an aerogel fire-retardant coating, which is prepared by the above method.

[0023] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0024] To improve the dispersibility of aerogel powder in resin and the weather resistance of the resin itself, this invention prepares and adds branched modified epoxy resin as a modifier in aerogel coatings. First, 9-fluorenone-2,7-dicarboxylic acid is used as a raw material and mixed with pentaerythritol. Under the catalysis of p-toluenesulfonic acid, a polyhydroxy branched intermediate with fluorenone as the center and alcohol hydroxyl groups at the end is synthesized. Then, the polyhydroxy branched intermediate is further reacted with hexafluoroglutaric acid, causing the carboxyl and hydroxyl groups in hexafluoroglutaric acid to react and graft, thereby introducing fluorine and forming a carboxyl-terminated terminal carboxyl branched intermediate.

[0025] Building upon this foundation, the present invention further utilizes 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane, which is epoxy-terminated and contains siloxane bonds, to react with a carboxyl-terminated branched intermediate, thereby ultimately preparing a branched modified epoxy resin. The silicon and fluorine elements present therein can significantly improve the epoxy resin's resistance to ultraviolet radiation and enhance its resistance to external acid and alkali environments, thereby extending the service life of the resin coating.

[0026] Furthermore, in the preparation of branched modified epoxy resin, the core used in this invention is 9-fluorenone-2,7-dicarboxylic acid. The fluorenone structure is rigid and can serve as a rigid core for the hyperbranched structure. Moreover, the fluorenone structure is rich in aromatic rings and carbonyl groups, exhibiting high molecular cohesion and strong thermal stability. It is not easily broken down into small molecules and volatilized at high temperatures, remaining in the system as a char skeleton, increasing the char content. At high temperatures, the carbonyl groups of fluorenone can undergo dehydration, dehydrogenation, and decarboxylation with the hydroxyl and ether bonds of the epoxy segments, promoting rapid cross-linking of the molecular chains and transformation into a graphitized aromatic ring structure, forming a continuous and dense solid carbon layer. Thus, even after the epoxy resin is damaged by high temperatures, the remaining carbon skeleton can still provide heat insulation. This invention also adds ammonium polyphosphate as a thermal expansion agent to the coating, enabling the formed carbon layer to have a porous and loose structure, reducing heat transfer. Attached Figure Description

[0027] Figure 1 This is a morphological image of the aerogel fireproof coating prepared in Example 1 of the present invention after 2 hours of combustion and spraying;

[0028] Figure 2 This is a surface morphology image of the aerogel fire-retardant coating prepared in Example 1 of the present invention before combustion spraying after 1 hour;

[0029] Figure 3 This is a surface morphology image of the aerogel fireproof coating prepared in Example 1 of the present invention after 1 hour of combustion and spraying. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0031] The aerogel particles used in the embodiments and comparative examples of this invention are Cabot ENOVA AEROGEL MT1200 hydrophobic silica aerogel particles; the titanium dioxide used has a particle size of 30~100nm; the reinforcing fiber used is commercially available glass fiber; and the curing agent used is polyamide 650.

[0032] Example 1

[0033] A method for preparing an aerogel fire-retardant coating includes the following steps:

[0034] S1. Mix 9-fluorenone-2,7-dicarboxylic acid with a reaction solvent, add pentaerythritol and p-toluenesulfonic acid, heat to 135°C under a nitrogen atmosphere, stir for 5 hours, and continuously remove the water generated during the reaction. After the reaction is completed, dry by rotary evaporation and remove excess reaction solvent to obtain a polyhydroxy branched intermediate.

[0035] The mass ratio of 9-fluorenone-2,7-dicarboxylic acid, pentaerythritol and p-toluenesulfonic acid is 1:1:0.03.

[0036] The mixed solvent is a liquid mixture of DMF and xylene in a mass ratio of 1:3;

[0037] S2. After mixing the polyhydroxy branched intermediate with DMF, the reaction system was cooled to 40°C, and triethylamine and hexafluoroglutaric acid were added and stirred until homogeneous. The temperature was increased to 75°C at a rate of 8°C / h, and the reaction was stirred at a constant temperature for 5h. The mixture was then dried by rotary evaporation to obtain the terminal carboxyl branched intermediate.

[0038] The mass ratio of the polyhydroxy branched intermediate, triethylamine, and hexafluoroglutaric acid is 1:0.03:1.9.

[0039] S3. After mixing the carboxyl-terminated branched intermediate with DMF, 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane was added and mixed evenly. The mixture was heated to 80°C and stirred for 5 hours. Excess solvent was removed by rotary evaporation. Deionized water was added to the rotary evaporated reaction system, and the mixture was stirred and allowed to stand. The organic phase was separated and washed again with anhydrous ethanol. After separating the lower aqueous phase, the remaining organic phase was rotary evaporated to remove excess ethanol and water, thus completing the purification process and obtaining the branched modified epoxy resin.

[0040] The mass ratio of the carboxyl-terminated branched intermediate to 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:1.

[0041] S4. After mixing aerogel particles, titanium dioxide, reinforcing fibers, ammonium polyphosphate and KH550 silane coupling agent evenly, add branched modified epoxy resin, stir and mix thoroughly, then add epoxy resin 601 and n-butanol, mix evenly, add curing agent, mix evenly, and obtain aerogel fireproof coating.

[0042] The mass ratio of aerogel particles, titanium dioxide, reinforcing fiber, ammonium polyphosphate, KH550 silane coupling agent, branched modified epoxy resin, epoxy resin 601, n-butanol and curing agent is 5:8:3:7:0.3:12:40:32:15.

[0043] Example 2

[0044] A method for preparing an aerogel fire-retardant coating includes the following steps:

[0045] S1. Mix 9-fluorenone-2,7-dicarboxylic acid with a reaction solvent, add pentaerythritol and p-toluenesulfonic acid, heat to 135°C under a nitrogen atmosphere, stir for 5 hours, and continuously remove the water generated during the reaction. After the reaction is completed, dry by rotary evaporation and remove excess reaction solvent to obtain a polyhydroxy branched intermediate.

[0046] The mass ratio of 9-fluorenone-2,7-dicarboxylic acid, pentaerythritol, and p-toluenesulfonic acid is 1:1.05:0.04.

[0047] The mixed solvent is a liquid mixture of DMF and xylene in a mass ratio of 1:4;

[0048] S2. After mixing the polyhydroxy branched intermediate with DMF, the reaction system was cooled to 30°C, and triethylamine and hexafluoroglutaric acid were added and stirred until homogeneous. The temperature was increased to 75°C at a rate of 6°C / h, and the reaction was stirred at a constant temperature for 4h. The mixture was then dried by rotary evaporation to obtain the terminal carboxyl branched intermediate.

[0049] The mass ratio of the polyhydroxy branched intermediate, triethylamine, and hexafluoroglutaric acid is 1:0.03:2.

[0050] S3. After mixing the terminal carboxyl branched intermediate with DMF, 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane was added and mixed evenly. The mixture was heated to 80°C and stirred for 4 hours. Excess solvent was removed by rotary evaporation. Deionized water was added to the rotary evaporated reaction system, and the mixture was stirred and allowed to stand. The organic phase was separated and washed again with anhydrous ethanol. After separating the lower aqueous phase, the remaining organic phase was rotary evaporated to remove excess ethanol and water, thus completing the purification process and obtaining the branched modified epoxy resin.

[0051] The mass ratio of the terminal carboxyl branched intermediate to 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:1.05.

[0052] S4. After uniformly mixing aerogel particles, titanium dioxide, reinforcing fibers, ammonium polyphosphate and KH560 silane coupling agent, add branched modified epoxy resin, stir and mix thoroughly, add epoxy resin 601 and n-butanol, mix thoroughly, add curing agent, mix thoroughly, and obtain aerogel fireproof coating.

[0053] The mass ratio of aerogel particles, titanium dioxide, reinforcing fiber, ammonium polyphosphate, KH560 silane coupling agent, branched modified epoxy resin, epoxy resin 601, n-butanol and curing agent is 8:10:5:10:0.7:18:52:48:15.

[0054] Example 3

[0055] A method for preparing an aerogel fire-retardant coating includes the following steps:

[0056] S1. Mix 9-fluorenone-2,7-dicarboxylic acid with a reaction solvent, add pentaerythritol and p-toluenesulfonic acid, heat to 135°C under a nitrogen atmosphere, stir for 5 hours, and continuously remove the water generated during the reaction. After the reaction is completed, dry by rotary evaporation and remove excess reaction solvent to obtain a polyhydroxy branched intermediate.

[0057] The mass ratio of 9-fluorenone-2,7-dicarboxylic acid, pentaerythritol, and p-toluenesulfonic acid is 1:1.1:0.05.

[0058] The mixed solvent is a liquid mixture of DMF and xylene in a mass ratio of 1:5;

[0059] S2. After mixing the polyhydroxy branched intermediate with DMF, the reaction system was cooled to 20°C, and triethylamine and hexafluoroglutaric acid were added and stirred until homogeneous. The temperature was then increased to 80°C at a rate of 4°C / h, and the reaction was stirred at a constant temperature for 3h. The mixture was then dried by rotary evaporation to obtain the terminal carboxyl branched intermediate.

[0060] The mass ratio of the polyhydroxy branched intermediate, triethylamine, and hexafluoroglutaric acid is 1:0.04:2.05.

[0061] S3. After mixing the terminal carboxyl branched intermediate with DMF, 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane was added and mixed evenly. The mixture was heated to 85°C and stirred for 3 hours. Excess solvent was removed by rotary evaporation. Deionized water was added to the rotary evaporated reaction system, and the mixture was stirred and allowed to stand. The organic phase was separated and washed again with anhydrous ethanol. After separating the lower aqueous phase, the remaining organic phase was rotary evaporated to remove excess ethanol and water, thus completing the purification and obtaining the branched modified epoxy resin.

[0062] The mass ratio of the terminal carboxyl branched intermediate to 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:1.1.

[0063] S4. After uniformly mixing aerogel particles, titanium dioxide, reinforcing fibers, ammonium polyphosphate and KH560 silane coupling agent, add branched modified epoxy resin, stir and mix thoroughly, add epoxy resin 601 and n-butanol, mix thoroughly, add curing agent, mix thoroughly, and obtain aerogel fireproof coating.

[0064] The mass ratio of aerogel particles, titanium dioxide, reinforcing fiber, ammonium polyphosphate, KH560 silane coupling agent, branched modified epoxy resin, epoxy resin 601, n-butanol and curing agent is 10.5:12:7:12:1:24:65:60:20.

[0065] Comparative Example 1

[0066] Compared with Example 1, this comparative example did not prepare branched modified epoxy resin, but directly added an equal amount of epoxy resin 601;

[0067] A method for preparing an aerogel fire-retardant coating includes the following steps:

[0068] S4. After uniformly mixing aerogel particles, titanium dioxide, reinforcing fibers, ammonium polyphosphate and KH550 silane coupling agent, epoxy resin 601 and n-butanol are added and mixed evenly. Then, curing agent is added and mixed evenly to obtain aerogel fireproof coating.

[0069] The mass ratio of aerogel particles, titanium dioxide, reinforcing fiber, ammonium polyphosphate, KH550 silane coupling agent, epoxy resin 601, n-butanol and curing agent is 5:8:3:7:0.3:52:32:15.

[0070] Comparative Example 2

[0071] Compared with Example 1, this comparative example did not use 9-fluorenone-2,7-dicarboxylic acid to prepare a polyhydroxy branching intermediate, but directly used only pentaerythritol in the subsequent reaction;

[0072] A method for preparing an aerogel fire-retardant coating includes the following steps:

[0073] S2. After mixing pentaerythritol and DMF evenly, the reaction system was cooled to 40°C, and triethylamine and hexafluoroglutaric acid were added to it. The mixture was stirred and mixed evenly. The temperature was increased to 75°C at a rate of 8°C / h, and the reaction was stirred at a constant temperature for 5h. The mixture was then dried by rotary evaporation to obtain the terminal carboxyl branched intermediate.

[0074] The mass ratio of pentaerythritol, triethylamine and hexafluoroglutaric acid is 1:0.03:7.

[0075] S3. After mixing the carboxyl-terminated branched intermediate with DMF, 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane was added and mixed evenly. The mixture was heated to 80°C and stirred for 5 hours. Excess solvent was removed by rotary evaporation. Deionized water was added to the rotary evaporated reaction system, and the mixture was stirred and allowed to stand. The organic phase was separated and washed again with anhydrous ethanol. After separating the lower aqueous phase, the remaining organic phase was rotary evaporated to remove excess ethanol and water, thus completing the purification process and obtaining the branched modified epoxy resin.

[0076] The mass ratio of the carboxyl-terminated branched intermediate to 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:1.

[0077] S4. After mixing aerogel particles, titanium dioxide, reinforcing fibers, ammonium polyphosphate and silane coupling agent evenly, add branched modified epoxy resin, stir and mix thoroughly, add epoxy resin 601 and n-butanol, mix evenly, add curing agent, mix evenly, and obtain aerogel fireproof coating.

[0078] The mass ratio of aerogel particles, titanium dioxide, reinforcing fiber, ammonium polyphosphate, silane coupling agent, branched modified epoxy resin, epoxy resin 601, n-butanol and curing agent is 5:8:3:7:0.3:12:40:32:15.

[0079] Testing: The aerogel fire-retardant coatings prepared in Examples 1-3 and Comparative Examples 1-2 were applied to the surface of a steel plate using the following construction process: First, a 1.5mm thick layer of composite aerogel coating was manually applied using a putty knife. Then, another 1.5mm thick layer of the same type of coating was applied. The application should be uniform and dense, without any missed areas or uneven surfaces. After the coating thickness met the construction requirements, the coating surface was rolled, and the edges were compacted and smoothed. This completed the first layer of composite aerogel coating. Next, a fiber mesh was fully laid on the surface of the first layer of coating and gently pressed with a scraper to ensure it was flat and adhered. Before the first layer of coating was completely cured, the second layer of composite aerogel coating was applied using the aforementioned construction method. The surface was then scraped smooth and even, without any unevenness. After standing for 5 days at a temperature of 25±2℃ and a relative humidity of 70±2%, the overall composite aerogel coating construction was completed.

[0080] The test samples of Examples 1-3 and Comparative Examples 1-2 were tested for crack resistance and damp heat resistance according to the GB / T 14907-2018 testing standard.

[0081] According to the GB / T 14907-2018 testing standard, the UV irradiation resistance of the test samples of Examples 1-3 and Comparative Examples 1-2 was tested, and the fire resistance performance was tested after UV aging.

[0082] According to the GB 14522-2008 testing standard, the surface of the test sample was observed after the coating underwent an artificial aging test for 1000 hours.

[0083] The coating surfaces of the test samples from Examples 1-3 and Comparative Examples 1-2 were heated using a hydrocarbon source flame at a temperature of 1050-1100℃. The temperature of the steel plate side was measured after 1 hour of heating. The morphology of the test sample from Example 1 before and after flame spraying was observed. See details below. Figure 2 , Figure 3 .

[0084] Meanwhile, the coating prepared in Example 1 was applied to the surface of a steel plate using the following construction process: First, a 3mm thick layer of composite aerogel coating was manually applied using a putty knife, followed by another 3mm thick layer of the same type of coating. The application was required to be uniform and dense, without any missed areas or uneven surfaces. After the coating thickness met the construction requirements, the coating surface was rolled, and the edges were compacted and smoothed, thus completing the first layer of composite aerogel coating. Next, a fiber mesh was laid fully on the surface of the first layer of coating, and gently pressed with a scraper to ensure it was flat and adhered. Before the first layer of coating was fully cured, the second layer of composite aerogel coating was applied using the aforementioned construction method. The surface was then scraped smooth and even, without any unevenness. After standing for 5 days at a temperature of 25±2℃ and a relative humidity of 70±2%, the overall composite aerogel coating construction was completed. The surface of the test sample was heated with a hydrocarbon source flame at a temperature of 1050~1100℃, and its morphology was observed after 2 hours of heating. See details below. Figure 1 .

[0085] The test results are shown in Table 1 below.

[0086] Table 1. Test results of aerogel fire-retardant coatings prepared in Examples 1-3 and Comparative Examples 1-2

[0087]

[0088] As can be seen from the table above, the aerogel coatings prepared in Examples 1 to 3 of the present invention can all achieve isolation of flame heat. The tested metal plate temperature is still below 200°C within 1 hour, which is far below the yield temperature of steel. It can effectively protect metal materials in fire environment. The data of Examples 1 to 3 also show that the aerogel coating prepared in the present invention has good toughness, water resistance and UV resistance, and can maintain good performance in outdoor environment.

[0089] As can be seen from the data of Example 1 and Comparative Example 1, without the preparation of branched modified epoxy resin, all data of Comparative Example 1 showed a partial decrease. Due to the absence of fluorine and silicon elements, the water resistance and UV resistance of Comparative Example 1 decreased significantly. Furthermore, due to the absence of hyperbranched resin, the dispersion effect of aerogel particles deteriorated, resulting in a decrease in the heat insulation effect of Comparative Example 1.

[0090] Comparative Example 2 data shows that without using 9-fluorenone-2,7-dicarboxylic acid to prepare a polyhydroxy branching intermediate, the final coating lacks the fluorenone structure to catalyze the resin carbonization, ultimately leading to an increase in the steel plate temperature during the thermal insulation performance test.

[0091] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing an aerogel fire-retardant coating, characterized in that: Includes the following steps: S1. Mix 9-fluorenone-2,7-dicarboxylic acid with a reaction solvent, add pentaerythritol and p-toluenesulfonic acid, heat under a nitrogen atmosphere, and dry by rotary evaporation to obtain a polyhydroxy branched intermediate. S2. Mix the polyhydroxy branched intermediate with DMF, add triethylamine and hexafluoroglutaric acid, stir and mix well, heat to react, and dry by rotary evaporation to obtain the terminal carboxyl branched intermediate; S3. The carboxyl-terminated branched intermediate was mixed with DMF, and 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane was added. The mixture was stirred, heated to react, rotary evaporated, washed and purified to obtain the branched modified epoxy resin. S4. After mixing aerogel particles, titanium dioxide, reinforcing fibers, ammonium polyphosphate and silane coupling agent, add branched modified epoxy resin, stir and mix well, add epoxy resin 601 and n-butanol, mix well, add curing agent, mix well, and obtain aerogel fireproof coating.

2. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S1, the mass ratio of 9-fluorenone-2,7-dicarboxylic acid, pentaerythritol, and p-toluenesulfonic acid is 1:(1~1.1):(0.03~0.05). The reaction solvent is a mixture of DMF and xylene, wherein the mass ratio of DMF to xylene is 1:(3~5).

3. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S1, during the heating reaction, the temperature is raised to 135~140℃, and the reaction is stirred for 4~5 hours, while the water generated during the reaction is continuously removed.

4. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S2, the mass ratio of the polyhydroxy branched intermediate, triethylamine, and hexafluoroglutaric acid is 1:(0.03~0.04):(1.9~2.05).

5. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S2, after the polyhydroxy branched intermediate is mixed with DMF, the reaction system is cooled to 20~40℃, and then triethylamine and hexafluoroglutaric acid are added to it. During the heating reaction, the temperature is increased to 75-80℃ at a rate of 4-8℃ / h, and then the reaction is stirred at a constant temperature for 3-5 hours.

6. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S3, the mass ratio of the terminal carboxyl branched intermediate to 1,1,3,3-tetramethyl-1,3-bis[3-(epoxyethylmethoxy)propyl]disiloxane is 1:(1~1.1).

7. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S3, when heating the reaction, the temperature is raised to 80~85℃ and the reaction is stirred for 3~5 hours; During washing and purification, deionized water is added to the reaction system after rotary evaporation, stirred and allowed to stand, the organic phase is separated, washed again with anhydrous ethanol, the lower aqueous phase is separated, and the remaining organic phase is rotary evaporated to remove excess ethanol and water, thus completing the purification.

8. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S4, the mass ratio of aerogel particles, titanium dioxide, reinforcing fiber, ammonium polyphosphate, silane coupling agent, branched modified epoxy resin, epoxy resin 601 to n-butanol and curing agent is (5~10.5):(8~12):(3~7):(7~12):(0.3~1):(12~24):(40~65):(32~60):(15~20).

9. The method for preparing an aerogel fire-retardant coating according to claim 1, characterized in that: In S4, the reinforcing fiber is glass fiber; the silane coupling agent is KH550 or KH560.

10. An aerogel fire-retardant coating prepared by the preparation method according to any one of claims 1 to 9.

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