An inorganic intumescent heat-insulating and fire-retardant coating and its preparation method

Abstract

This application belongs to the technical field of flame-retardant intumescent thermal insulation materials, specifically providing an inorganic intumescent thermal insulation fireproof coating and its preparation method. The inorganic intumescent thermal insulation fireproof coating comprises the following components: potassium silicate solution, aluminum dihydrogen phosphate, porous composite filler, melamine, pentaerythritol, aluminum hydroxide, glass powder, expandable graphite, mullite fiber, BYK-025 defoamer, sodium tripolyphosphate dispersant, and hydroxypropyl methylcellulose thickener. The inorganic intumescent thermal insulation fireproof coating obtained by this application exhibits excellent bonding strength, high-temperature structural stability, and controllable expansion, making it suitable for fire protection in scenarios such as new energy battery boxes and steel structure buildings, and capable of meeting stringent fire protection requirements.

Description

Technical Field

[0001] This application belongs to the technical field of flame-retardant intumescent insulation materials, and in particular relates to an inorganic intumescent fireproof insulation coating and its preparation method. Background Technology

[0002] With the booming development of the new energy vehicle industry and the widespread application of lithium batteries, lithium-ion battery containers have become a hot topic. Their flexible and efficient energy storage and power supply characteristics enable a stable power supply, making them a vital force driving the rapid development of the new energy vehicle industry and related fields. However, in the context of high energy density, battery safety has become a significant issue. Against this backdrop, the development of high-performance heat-insulating and fire-retardant coatings has become a key breakthrough, which can greatly reduce personal injury and economic losses, making it both necessary and significant.

[0003] Intumescent fire-resistant insulating coatings typically achieve their insulation and fire-retardant effects through the material's expansion properties. At room temperature, they have a low space occupation ratio, but expand rapidly when heated, forming a low thermal conductivity state, thus significantly reducing heat conduction and blocking the propagation of thermal runaway. This has gradually become a research hotspot in the field of thermal protection. However, lithium-ion battery container substrates have poor surface adhesion strength, and intumescent fire-resistant insulating coatings are prone to adhesion failure after expansion under thermal runaway conditions, leading to easy peeling of the coating from the substrate. Therefore, developing an intumescent fire-resistant insulating coating that provides satisfactory insulation performance and thermal stability, while also possessing high compressive strength and good interfacial adhesion, is of great significance.

[0004] Patent application CN113122124A discloses an intumescent flame-retardant and heat-insulating fireproof coating and its preparation method. This technology employs a compound design of inorganic and organic flame retardants. The inorganic flame retardant inhibits the generation of combustible gases by absorbing heat and lowering the temperature, while the organic flame retardant forms a glassy carbonized layer to isolate oxygen. This dual mechanism improves flame-retardant reliability and extends protection time. However, this technology does not control gas release; the gas is released instantaneously when heated, easily leading to coating peeling. The carbonized layer is only an organic carbonized layer, which is prone to pulverization at high temperatures. Additionally, patent application CN112778864A discloses a water-based intumescent fireproof coating based on halloysite and its preparation method. This technology introduces a composite filler of halloysite nanotubes and titanium dioxide into the traditional intumescent system, achieving improvements in filler synergistic design, the environmental friendliness of the water-based system, and the strengthening of the carbonized layer structure. However, this technology relies on the physical heat insulation of the organic carbonized intumescent carbonized layer, which gradually pyrolyzes, burns, and pulverizes under high temperatures, making it difficult to achieve continuous and effective high-temperature protection. Summary of the Invention

[0005] To address the aforementioned issues and further resolve problems such as easy coating detachment upon heating, easy pulverization of the char layer at high temperatures, and excessively rapid gas release in existing technologies, this application provides an inorganic intumescent heat-insulating and fire-retardant coating and its preparation method.

[0006] This application first provides an inorganic intumescent heat-insulating and fire-retardant coating, comprising the following raw materials in parts by weight: 30 parts potassium silicate solution, 10-14 parts aluminum dihydrogen phosphate, 10-14 parts porous composite filler, 5-7 parts melamine, 5-7 parts pentaerythritol, 13-17 parts aluminum hydroxide, 6-10 parts glass powder, 3-5 parts expandable graphite, 5-7 parts mullite fiber, 0.3-0.5 parts BYK-025 defoamer, 0.3-0.5 parts sodium tripolyphosphate dispersant, and 0.1-0.3 parts hydroxypropyl methylcellulose thickener; wherein the porous composite filler is prepared from porous magnesium carbonate, methyl silicate, dimethyl dimethoxysilane, and boric acid.

[0007] Furthermore, the preparation method of the porous composite filler includes the following steps:

[0008] Magnesium chloride hexahydrate was dissolved in ethanol, triethylamine was added, CO2 was introduced, and the mixture was aged, washed, and dried to obtain porous magnesium carbonate.

[0009] Porous magnesium carbonate is uniformly dispersed in ethanol to form a porous magnesium carbonate suspension; boric acid is dispersed in a mixed solution of deionized water and ethanol to obtain a boric acid solution; methyl silicate, dimethyl dimethoxysilane and ethanol are uniformly dispersed, the pH is adjusted and the temperature is raised and stirred, then the porous magnesium carbonate suspension and boric acid solution are added and stirring is continued to carry out boron-doped polysiloxane coating, finally polycarboxylate dispersant is added and stirred, the precipitate is collected by centrifugation, washed and dried to obtain the porous composite filler.

[0010] Furthermore, the mass ratio of magnesium chloride hexahydrate to triethylamine is (8-12):15.

[0011] Furthermore, the mass ratio of porous magnesium carbonate to methyl silicate is 15:(3-7).

[0012] Furthermore, the temperature for the heating is 40-60°C.

[0013] Furthermore, the aging time is 60-84 hours.

[0014] Furthermore, the pH is 8.5-9.5.

[0015] This application also provides a method for preparing an inorganic intumescent heat-insulating and fire-retardant coating, comprising the following steps:

[0016] 1) Premix porous composite filler, melamine, pentaerythritol, aluminum hydroxide, glass powder and sodium tripolyphosphate dispersant; then add mullite fiber and stir; finally add expandable graphite and stir at low speed to obtain component A;

[0017] 2) Slowly add aluminum dihydrogen phosphate to potassium silicate solution and stir until homogeneous to obtain component B;

[0018] 3) Add component A to component B and stir, then add hydroxypropyl methylcellulose and stir, and finally add BYK-025 defoamer and continue stirring to obtain the final product.

[0019] Furthermore, the premixing time in step 1) is 3-10 minutes.

[0020] Furthermore, the stirring time in step 2) is 15-25 minutes.

[0021] Compared with the prior art, this application has the following beneficial effects:

[0022] 1. The porous magnesium carbonate prepared by the sol-gel method in this application has a high specific surface area, which allows for a more complete thermal decomposition reaction and a higher heat absorption efficiency per unit mass. This can more effectively reduce the internal temperature of the coating and enhance the flame retardant and cooling effect. At the same time, the porous structure slows down the CO2 diffusion rate, avoiding coating blistering and peeling caused by instantaneous gas release upon heating. In addition, the porous structure allows for more thorough thermal decomposition of magnesium carbonate, resulting in a more sufficient amount of CO2 released per unit mass, which can provide a sufficient gas source for coating expansion and ensure the expansion ratio.

[0023] 2. The porous composite filler prepared in this application can improve the compressive strength and structural integrity of the coating, effectively absorb and disperse internal stress during high-temperature expansion, thereby reducing the risk of cracking or even coating peeling caused by stress concentration. Furthermore, the introduction of boric acid during the preparation process allows boron atoms to be introduced in the form of BO-Si bonds, significantly improving the filler's density and high-temperature resistance.

[0024] 3. This application coats the surface of porous magnesium carbonate with boron-doped polysiloxane. On the one hand, it can effectively block moisture intrusion at room temperature, preventing the porous magnesium carbonate from absorbing moisture and pre-decomposing. At the same time, it can resist external impacts during coating grinding and construction, protecting its porous structure and functional integrity. On the other hand, under high temperature conditions, the polysiloxane coating layer can inhibit the agglomeration of MgO generated after the release of CO2 from the porous magnesium carbonate, thus improving the structural integrity of the expanded carbon layer. Meanwhile, the MgO generated in situ can provide internal support for the boron-doped polysiloxane. The two work synergistically to improve the mechanical properties and high-temperature stability of the coating. Attached Figure Description

[0025] Figure 1The N2 adsorption-desorption isotherm curve of the porous composite packing prepared in Example 1 of this application.

[0026] Figure 2 This is a photograph of the inorganic intumescent heat-insulating and fire-retardant coating prepared in Example 1 of this application after thermal expansion. Detailed Implementation

[0027] To make the inventive objectives, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. Obviously, the described embodiments are only a portion of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0030] The terms "preferred," "more preferably," "better," and "even better" used in this application refer to embodiments of this application that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferred," "more preferably," "better," and "even better" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application.

[0031] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0032] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0033] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0034] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0035] In this application, "above" or "below" includes the stated number. For example, "below 1" includes 1.

[0036] In this application, room temperature refers to 0~40℃, including but not limited to 10~40℃, or further to 20~30℃.

[0037] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0038] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0039] Example 1

[0040] The inorganic intumescent heat-insulating and fire-retardant coating prepared in this embodiment comprises the following components: 30 kg potassium silicate solution, 12 kg aluminum dihydrogen phosphate, 12 kg porous composite filler, 6 kg melamine, 6 kg pentaerythritol, 15 kg aluminum hydroxide, 8 kg glass powder, 4 kg expandable graphite, 6 kg mullite fiber, 0.4 kg BYK-025 defoamer, 0.4 kg sodium tripolyphosphate dispersant, and 0.2 kg hydroxypropyl methylcellulose thickener.

[0041] The method for preparing the porous composite packing in this embodiment includes the following steps:

[0042] Mix 20g of magnesium chloride hexahydrate with 300mL of ethanol, add 30g of triethylamine and stir for 10min, then pass CO2 gas through and maintain for 30min, then age at room temperature and pressure for 72h, enrich and concentrate, wash with ethanol 3 times, and dry to obtain porous magnesium carbonate.

[0043] 30g of porous magnesium carbonate was mixed with 200mL of ethanol to obtain a porous magnesium carbonate suspension. 0.5g of boric acid, 5mL of deionized water, and 5mL of ethanol were mixed to obtain a boric acid solution. 10g of methyl silicate, 5g of dimethyl dimethoxysilane, and 40mL of ethanol were mixed, and ammonia was slowly added dropwise to adjust the pH of the system to 9.0. The mixture was heated to 50℃ in a water bath and stirred for 30min. Then, the porous magnesium carbonate suspension and boric acid solution were added, and stirring was continued for 2h to coat the boron-doped polysiloxane. Finally, 0.5g of polycarboxylate dispersant was added, and the mixture was stirred for 30min. The precipitate was collected by centrifugation, washed three times with ethanol, and dried under vacuum at 60℃ to obtain a porous composite filler.

[0044] The preparation method of the inorganic intumescent heat-insulating and fire-retardant coating in this embodiment includes the following steps:

[0045] Premix porous composite filler, melamine, pentaerythritol, aluminum hydroxide, glass powder and sodium tripolyphosphate dispersant for 5 min; then add mullite fiber and continue stirring for 5 min; finally add expandable graphite and stir at low speed for 3 min to obtain component A;

[0046] Aluminum dihydrogen phosphate was slowly added to a potassium silicate solution and stirred for 20 minutes to obtain component B.

[0047] Add component A to component B and stir for 10 minutes. Then add hydroxypropyl methylcellulose and stir for 2 minutes. Finally, add BYK-025 defoamer and continue stirring for 5 minutes to obtain the final product.

[0048] Example 2

[0049] The inorganic intumescent heat-insulating and fire-retardant coating prepared in this embodiment comprises the following components: 30 kg potassium silicate solution, 10 kg aluminum dihydrogen phosphate, 10 kg porous composite filler, 5 kg melamine, 5 kg pentaerythritol, 13 kg aluminum hydroxide, 6 kg glass powder, 3 kg expandable graphite, 5 kg mullite fiber, 0.3 kg BYK-025 defoamer, 0.3 kg sodium tripolyphosphate dispersant, and 0.1 kg hydroxypropyl methylcellulose thickener.

[0050] The method for preparing the porous composite packing in this embodiment includes the following steps:

[0051] Mix 16g of magnesium chloride hexahydrate with 300mL of ethanol, add 30g of triethylamine and stir for 10min, then purge with CO2 gas for 30min, and then age at room temperature and pressure for 60h. After enrichment and concentration, wash with ethanol three times and dry to obtain porous magnesium carbonate.

[0052] 30g of porous magnesium carbonate was mixed with 200mL of ethanol to obtain a porous magnesium carbonate suspension. 0.5g of boric acid, 5mL of deionized water, and 5mL of ethanol were mixed to obtain a boric acid solution. 6g of methyl silicate, 5g of dimethyldimethoxysilane, and 40mL of ethanol were mixed, and ammonia was slowly added dropwise to adjust the pH of the system to 8.5. The mixture was heated to 40℃ in a water bath and stirred for 30min. Then, the porous magnesium carbonate suspension and boric acid solution were added, and stirring was continued for 2h to coat the boron-doped polysiloxane. Finally, 0.5g of polycarboxylate dispersant was added, and the mixture was stirred for 30min. The precipitate was collected by centrifugation, washed three times with ethanol, and dried under vacuum at 60℃ to obtain a porous composite filler.

[0053] The preparation method of the inorganic intumescent heat-insulating and fire-retardant coating in this embodiment includes the following steps:

[0054] Premix the porous composite filler, melamine, pentaerythritol, aluminum hydroxide, glass powder and sodium tripolyphosphate dispersant for 3 min; then add mullite fiber and continue stirring for 5 min; finally add expandable graphite and stir at low speed for 3 min to obtain component A.

[0055] Aluminum dihydrogen phosphate was slowly added to a potassium silicate solution and stirred for 15 minutes to obtain component B.

[0056] Add component A to component B and stir for 10 minutes. Then add hydroxypropyl methylcellulose and stir for 2 minutes. Finally, add BYK-025 defoamer and continue stirring for 5 minutes to obtain the final product.

[0057] Example 3

[0058] The inorganic intumescent heat-insulating and fire-retardant coating prepared in this embodiment comprises the following components: 30 kg potassium silicate solution, 14 kg aluminum dihydrogen phosphate, 14 kg porous composite filler, 7 kg melamine, 7 kg pentaerythritol, 17 kg aluminum hydroxide, 10 kg glass powder, 5 kg expandable graphite, 7 kg mullite fiber, 0.5 kg BYK-025 defoamer, 0.5 kg sodium tripolyphosphate dispersant, and 0.3 kg hydroxypropyl methylcellulose thickener.

[0059] The method for preparing the porous composite packing in this embodiment includes the following steps:

[0060] Mix 24g of magnesium chloride hexahydrate with 300mL of ethanol, add 30g of triethylamine and stir for 10min, then purge with CO2 gas for 30min, and then age at room temperature and pressure for 84h. After enrichment and concentration, wash with ethanol 3 times and dry to obtain porous magnesium carbonate.

[0061] 30g of porous magnesium carbonate was mixed with 200mL of ethanol to obtain a porous magnesium carbonate suspension. 0.5g of boric acid, 5mL of deionized water, and 5mL of ethanol were mixed to obtain a boric acid solution. 14g of methyl silicate, 5g of dimethyldimethoxysilane, and 40mL of ethanol were mixed, and ammonia was slowly added dropwise to adjust the pH of the system to 9.5. The mixture was heated to 60℃ in a water bath and stirred for 30min. Then, the porous magnesium carbonate suspension and boric acid solution were added, and stirring was continued for 2h to coat the boron-doped polysiloxane. Finally, 0.5g of polycarboxylate dispersant was added, and the mixture was stirred for 30min. The precipitate was collected by centrifugation, washed three times with ethanol, and dried under vacuum at 60℃ to obtain a porous composite filler.

[0062] The preparation method of the inorganic intumescent heat-insulating and fire-retardant coating in this embodiment includes the following steps:

[0063] The porous composite filler, melamine, pentaerythritol, aluminum hydroxide, glass powder and sodium tripolyphosphate dispersant were premixed for 10 min; then mullite fiber was added and stirring was continued for 5 min; finally, expandable graphite was added and stirred at low speed for 3 min to obtain component A.

[0064] Aluminum dihydrogen phosphate was slowly added to a potassium silicate solution and stirred for 25 minutes to obtain component B.

[0065] Add component A to component B and stir for 10 minutes. Then add hydroxypropyl methylcellulose and stir for 2 minutes. Finally, add BYK-025 defoamer and continue stirring for 5 minutes to obtain the final product.

[0066] Control group 1

[0067] The inorganic intumescent heat-insulating and fire-retardant coating prepared in this control group includes the following components: 30 kg potassium silicate solution, 12 kg aluminum dihydrogen phosphate, 12 kg porous composite filler, 6 kg melamine, 6 kg pentaerythritol, 15 kg aluminum hydroxide, 8 kg glass powder, 4 kg expandable graphite, 6 kg mullite fiber, 0.4 kg BYK-025 defoamer, 0.4 kg sodium tripolyphosphate dispersant, and 0.2 kg hydroxypropyl methylcellulose thickener.

[0068] The preparation method of the porous composite packing in this control group includes the following steps:

[0069] Mix 20g magnesium chloride hexahydrate with 300mL ethanol until homogeneous, add 30g triethylamine and stir for 10min, then introduce CO2 gas and maintain for 30min, then age at room temperature and pressure for 72h, enrich and concentrate, wash with ethanol 3 times, and dry to obtain the porous composite packing.

[0070] The preparation method of the inorganic intumescent heat-insulating and fire-retardant coating in this control group includes the following steps:

[0071] Premix porous composite filler, melamine, pentaerythritol, aluminum hydroxide, glass powder and sodium tripolyphosphate dispersant for 5 min; then add mullite fiber and continue stirring for 5 min; finally add expandable graphite and stir at low speed for 3 min to obtain component A;

[0072] Aluminum dihydrogen phosphate was slowly added to a potassium silicate solution and stirred for 20 minutes to obtain component B.

[0073] Add component A to component B and stir for 10 minutes. Then add hydroxypropyl methylcellulose and stir for 2 minutes. Finally, add BYK-025 defoamer and continue stirring for 5 minutes to obtain the final product.

[0074] Control group 2

[0075] The inorganic intumescent heat-insulating and fire-retardant coating prepared in this control group includes the following components: 30 kg potassium silicate solution, 12 kg aluminum dihydrogen phosphate, 6 kg melamine, 6 kg pentaerythritol, 15 kg aluminum hydroxide, 8 kg glass powder, 4 kg expandable graphite, 6 kg mullite fiber, 0.4 kg BYK-025 defoamer, 0.4 kg sodium tripolyphosphate dispersant, and 0.2 kg hydroxypropyl methylcellulose thickener.

[0076] The preparation method of the inorganic intumescent heat-insulating and fire-retardant coating in this control group includes the following steps:

[0077] Melamine, pentaerythritol, aluminum hydroxide, glass powder, and sodium tripolyphosphate dispersant were premixed for 5 minutes; then mullite fiber was added and stirring was continued for 5 minutes; finally, expandable graphite was added and stirred at low speed for 3 minutes to obtain component A.

[0078] Aluminum dihydrogen phosphate was slowly added to a potassium silicate solution and stirred for 20 minutes to obtain component B.

[0079] Add component A to component B and stir for 10 minutes. Then add hydroxypropyl methylcellulose and stir for 2 minutes. Finally, add BYK-025 defoamer and continue stirring for 5 minutes to obtain the final product.

[0080] Performance testing

[0081] 1. Coating Fire Resistance Test: A fire-resistant coating fire resistance device was prepared using an iron stand, a portable pyrometer, thermocouples, and a gas canister. The gas canister was placed under the sample coating. The distance between the steel plate coating and the Bunsen burner outlet was adjusted to 7-8 cm using the bracket on the iron stand. The coated side faced the flame. The thermocouple was then fixed in the center of the back of the steel plate, ensuring it was flush against the back of the plate to minimize error. The back of the steel plate was covered with fireproof cotton. The Bunsen burner was lit, and the blue flame was adjusted to approximately 10 cm. The burner was then moved to the center of the coating. The temperature on the back of the steel plate was observed and recorded every 1 minute. The test was completed after 60 minutes, and the flame was turned off. Coating Expansion Ratio: The thickness of the coating before the fire resistance test (d0) was measured. After the fire resistance test, the average thickness of the coating after expansion (d1) was measured. Expansion ratio = (d1-d0) / d0.

[0082] 2. Non-combustible rating test: The combustion performance is tested in accordance with the "Classification of Combustion Performance of Building Materials and Products" (GB8624-2012).

[0083] 3. Adhesion strength: The adhesion strength of the inorganic intumescent heat-insulating fireproof coatings prepared in Examples 1-3 and Control Groups 1-2 was tested in accordance with GB14907-2018 Fireproof Coatings for Steel Structures.

[0084] Table 1 Performance test results of inorganic intumescent heat-insulating and fire-retardant coatings

[0085] Sample Backplate temperature ℃ expansion multiple times Expansion layer structure Non-flammable rating Bond strength (MPa) Example 1 277 2.3 dense Class A Non-combustible 0.78 Example 2 292 2.2 dense Class A Non-combustible 0.74 Example 3 283 1.9 dense Class A Non-combustible 0.76 Control group 1 326 2.6 Hollow Class A Non-combustible 0.72 Control group 2 338 2.8 loose Class A Non-combustible 0.69

[0086] Analysis of Examples 1-3 and Control Groups 1-2 and in combination Figure 1-2 As can be seen from the test data in Table 1, the inorganic intumescent heat-insulating fireproof coating prepared in this application has excellent fire resistance, bonding strength, and char layer structural stability. Compared with Examples 1-3, the porous composite filler used in the inorganic intumescent heat-insulating fireproof coating prepared in Control Group 1 was not coated, resulting in a significant reduction in its fire resistance. The test results show that the backing plate temperature was higher, and although the expansion ratio was larger, the char layer structure was loose, and the bonding strength was significantly reduced. This indicates that although the uncoated porous composite filler can decompose and release gas to promote expansion, the lack of a coating layer for protection and reinforcement leads to a decrease in the structural strength of the coating after expansion, making it prone to cracking and peeling, ultimately affecting the overall fireproof effect and durability. Compared with Examples 1-3, no porous composite filler was added in Control Group 2. The backing plate temperature was higher, the expansion ratio was lower, the char layer was loose and brittle, and the bonding strength was low. This proves that the porous composite filler introduced in this application plays a key role in improving the overall performance of the coating. In summary, this application has successfully prepared an inorganic intumescent heat-insulating fireproof coating with high bonding strength, excellent fire resistance and a stable intumescent char layer through specific component design and preparation methods.

[0087] Although this application 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 this application should be included within the protection scope of this application.

Claims

1. An inorganic intumescent heat-insulating and fire-retardant coating, characterized in that, The raw materials include the following parts by weight: 30 parts potassium silicate solution, 10-14 parts aluminum dihydrogen phosphate, 10-14 parts porous composite filler, 5-7 parts melamine, 5-7 parts pentaerythritol, 13-17 parts aluminum hydroxide, 6-10 parts glass powder, 3-5 parts expandable graphite, 5-7 parts mullite fiber, 0.3-0.5 parts BYK-025 defoamer, 0.3-0.5 parts sodium tripolyphosphate dispersant, and 0.1-0.3 parts hydroxypropyl methylcellulose thickener; the porous composite filler is prepared from porous magnesium carbonate, methyl silicate, dimethyl dimethoxysilane, and boric acid.

2. The inorganic intumescent heat-insulating and fire-retardant coating according to claim 1, characterized in that, The preparation method of the porous composite filler includes the following steps: Magnesium chloride hexahydrate was dissolved in ethanol, triethylamine was added, CO2 was introduced, and the mixture was aged, washed, and dried to obtain porous magnesium carbonate. Porous magnesium carbonate is uniformly dispersed in ethanol to form a porous magnesium carbonate suspension. Boric acid was dispersed in a mixed solution of deionized water and ethanol to obtain a boric acid solution. Methyl silicate, dimethyl dimethoxysilane and ethanol were dispersed evenly, the pH was adjusted and the temperature was raised and stirred. Then, a porous magnesium carbonate suspension and the boric acid solution were added and stirring was continued to carry out boron-doped polysiloxane coating. Finally, a polycarboxylate dispersant was added and stirred. The precipitate was collected by centrifugation, washed and dried to obtain a porous composite packing.

3. The inorganic intumescent heat-insulating and fire-retardant coating according to claim 2, characterized in that: The mass ratio of magnesium chloride hexahydrate to triethylamine is (8-12):

15.

4. The inorganic intumescent heat-insulating and fire-retardant coating according to claim 2, characterized in that: The mass ratio of porous magnesium carbonate to methyl silicate is 15:(3-7).

5. The inorganic intumescent heat-insulating and fire-retardant coating according to claim 2, characterized in that: The temperature for the heating is 40-60℃.

6. The inorganic intumescent heat-insulating and fire-retardant coating according to claim 2, characterized in that: The aging time is 60-84 hours.

7. The inorganic intumescent heat-insulating and fire-retardant coating according to claim 2, characterized in that: The pH value is 8.5-9.

5.

8. A method for preparing an inorganic intumescent heat-insulating and fire-retardant coating, characterized in that, Includes the following steps: 1) Premix porous composite filler, melamine, pentaerythritol, aluminum hydroxide, glass powder and sodium tripolyphosphate dispersant; then add mullite fiber and stir; finally add expandable graphite and stir at low speed to obtain component A; 2) Slowly add aluminum dihydrogen phosphate to potassium silicate solution and stir until homogeneous to obtain component B; 3) Add component A to component B and stir, then add hydroxypropyl methylcellulose and stir, and finally add BYK-025 defoamer and continue stirring to obtain the final product.

9. The preparation method of an inorganic intumescent heat-insulating and fire-retardant coating according to claim 8, characterized in that: The premixing time in step 1) is 3-10 minutes.

10. The method for preparing an inorganic intumescent heat-insulating and fire-retardant coating according to claim 8, characterized in that: The stirring time in step 2) is 15-25 minutes.

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