Metal-organic framework microcapsule, perfluorocyclohexanone fire extinguishing microcapsule, and preparation method and application thereof

Abstract

This invention belongs to the field of fire extinguishing technology, and relates to a metal-organic framework microcapsule, a perfluorohexanone (PFH) fire extinguishing microcapsule, its preparation method, and its application. A metal-organic framework microcapsule is prepared by the following method: a mixture of an organic iron source, trimesic acid, hexamine molybdate, hexamethylenetetramine, polyvinylpyrrolidone, and thioacetamide is reacted hydrothermally to obtain the metal-organic framework microcapsule. When the metal-organic framework microcapsule of this invention is used as the shell of a PFH fire extinguishing microcapsule, it can reduce the response temperature, achieving the effect of releasing PFH starting at 90°C and completely releasing PFH at 100-110°C. This allows for rapid fire extinguishing in the early stages of a fire, and it also has excellent adsorption effects on PFH. A smaller number of fire extinguishing microcapsules are needed to extinguish the fire. Furthermore, after the complete release of PFH, it can repeatedly adsorb PFH, enabling multiple reuses.

Description

Technical Field

[0001] This invention relates to the field of fire extinguishing technology, and more specifically, to a metal-organic framework microcapsule, a perfluorohexanone fire extinguishing microcapsule, its preparation method, and its application. Background Technology

[0002] Gas fire extinguishers, dry powder fire extinguishers, and water-based fire extinguishers can cause irreversible damage to electronic equipment, and therefore are not suitable for extinguishing fires in equipment such as new energy storage devices, power cabinets, data cabinets, and containers.

[0003] Perfluorohexanone (CAS No. 756-13-8) is a novel environmentally friendly fire extinguishing agent. It is a liquid at room temperature, with a heat of vaporization only 1 / 25 that of water, while its vapor pressure is 25 times that of water. These properties make it easily vaporized and able to rapidly absorb heat to achieve a fire extinguishing effect, making it a long-term and durable alternative to halon fire extinguishers. However, due to its boiling point of only 49°C, its use as a fire extinguishing agent is still somewhat limited. Currently, it is typically used as a replacement for halon fire extinguishers, or in total flooding systems and localized application systems for Class B fire protection. In practical applications, it usually needs to be stored in fire extinguishing tanks or requires a dedicated fire extinguishing system, making fire extinguishing inconvenient.

[0004] To better apply to various fire prevention and extinguishing scenarios, existing technologies typically employ microcapsule extinguishing technology, which encapsulates perfluorohexanone extinguishing agents into multiple tiny capsules, suitable for the complex internal structures and small gaps of electrical equipment.

[0005] Common perfluorohexanone microcapsules require the addition of large amounts of emulsifiers and stabilizers, affecting their fire extinguishing effectiveness and causing varying degrees of toxicity to the environment and human health during the fire extinguishing process. Examples include nonylphenol polyoxyethylene ether emulsifiers and urea-formaldehyde resin capsule walls. The former decomposes to produce endocrine disruptors, posing a potential health hazard to maintenance personnel and others handling the equipment, while the latter may release carcinogenic formaldehyde at high temperatures. The high volatility of perfluorohexanone makes this type of capsule difficult to store for extended periods, hindering its commercial application.

[0006] To address the aforementioned issues, existing technology discloses a perfluorohexanone fire extinguishing microcapsule. The preparation method includes the following steps: S1, dissolving gelatin and montmorillonite in pure water to obtain a dispersion; S2, dissolving sodium polyphosphate in pure water to obtain a coagulated solution; S3, first adding liquid perfluorohexanone to the dispersion and dispersing it evenly, then adding the coagulated solution and stirring to form an inner shell layer; S4, first adding polyisocyanate to the liquid perfluorohexanone forming the inner shell layer for a first curing process, then adding phenolic prepolymer for a second curing process to form an outer shell layer, followed by washing, filtering, and drying to produce the perfluorohexanone fire extinguishing microcapsule. However, this perfluorohexanone fire extinguishing microcapsule only exhibits significant mass loss at 150°C, its response temperature is too high, and it cannot quickly extinguish fires in the early stages. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing perfluorohexanone fire extinguishing microcapsules, which require the shell material to break down and release perfluorohexanone at 150°C, resulting in an excessively high response temperature. This invention provides a metal-organic framework microcapsule that, when used as the capsule shell for perfluorohexanone fire extinguishing microcapsules, can reduce the response temperature.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution: A metal-organic framework microcapsule is prepared by the following method: a mixture of an organic iron source, trimesic acid, hexamine molybdate, hexamethylenetetramine, polyvinylpyrrolidone, and thioacetamide is reacted hydrothermally to obtain the metal-organic framework microcapsule. The iron source of the organism is iron acetylacetone and / or iron hexafluoroacetylacetone; The molar ratio of the organic iron source to trimesic acid is (0.4~1):1; The molar ratio of the organic iron source to hexamine molybdate is (1~9):1; The molar ratio of the organic iron source to hexamethylenetetramine is (0.2~0.8):1; The molar ratio of the organic iron source to polyvinylpyrrolidone is (0.1~0.6):1; The molar ratio of the organic iron source to thioacetamide is (0.4~1.7):1; The hydrothermal reaction temperature is 120~240 ℃, and the hydrothermal reaction time is 8~24 h.

[0009] This invention uses trimesic acid as the core ligand, which forms metal-organic framework microcapsules through coordination bonds with iron ions in the organic iron source and molybdenum ions in hexamethylene molybdate during a hydrothermal reaction. In the hydrothermal reaction, hexamethylenetetramine can act as an organic amine regulator to control the growth rate and direction of the metal-organic framework crystal nuclei, assisting in the formation of specific microcapsule morphologies and avoiding random aggregation of crystal grains. Polyvinylpyrrolidone, as a polymeric surfactant, is adsorbed on the surface of the metal-organic framework crystal nuclei to prevent crystal nuclei aggregation. The sulfur element in thioacetamide is combined in the metal-organic framework in a coordination or doping form to optimize the adsorption sites of the material.

[0010] The metal-organic framework microcapsules of this invention can reduce the response temperature of perfluorohexanone fire extinguishing microcapsules. The core of this invention is that the iron-based metal-organic framework constructed by its components has suitable thermal response characteristics. The coordination bond energy formed by iron ions and trimesic acid is moderate. At 90~110°C, the thermal energy causes the framework pores to relax and open. The structural stress introduced by hexamethylene molybdate doping accelerates this process. The SM (sulfur-metal) coordination bond formed by thioacetamide breaks first, becoming the breakthrough point for pore opening. At the same time, the mesoporous and loose structure constructed by hexamethylenetetramine and polyvinylpyrrolidone allows for rapid heat transfer, causing the shell pores to open rapidly. Moreover, the framework and perfluorohexanone are only bound by van der Waals forces and hydrophobic interactions. The fire extinguishing microcapsules can be rapidly desorbed and released, achieving a rapid response temperature effect of releasing at 90°C and fully releasing at 100~110°C. Moreover, during the desorption and release of perfluorohexanone from the fire extinguishing microcapsules, the organometallic framework shell did not undergo overall dissociation or skeletal collapse; only the channels opened thermally. There was no irreversible breakage of coordination bonds or destruction of the crystal structure. When the temperature dropped to room temperature, the coordination bonds of the framework could regain stability, the channel structure closed, and the adsorption sites formed by dopants such as sulfur and molybdenum remained active. The specific surface area and pore volume of the microcapsules did not decrease significantly. Therefore, the metal-organic framework microcapsules of the present invention can be adsorbed and bound to perfluorohexanone again, enabling reuse.

[0011] The metal-organic framework microcapsules of this invention exhibit excellent encapsulation properties for perfluorohexanone and maintain structural integrity under high-temperature conditions. This prevents the release of the fire extinguishing microcapsules before a fire occurs or when unnecessary, ensuring that the microcapsules function at the most critical moment. This enhances the release effect of perfluorohexanone and improves the overall system safety and fire extinguishing effectiveness. They possess an autonomous activation function; when the ambient temperature reaches a certain threshold or a fire signal is detected, the microcapsules automatically rupture, achieving automatic fire extinguishing without external intervention. This is particularly important for unattended equipment such as new energy storage devices and data cabinets. The microcapsules are small and lightweight, allowing them to be embedded inside or on the surface of energy storage devices, power cabinets, and other equipment without occupying extra space. Installation is convenient and does not affect the normal operation and maintenance of the equipment.

[0012] Preferably, the molar ratio of the organic iron source to trimesic acid is (0.43~0.62):1. This molar ratio is beneficial to improving the adsorption effect of metal-organic framework microcapsules on perfluorohexanone.

[0013] Preferably, the molar ratio of the organic iron source to hexamine molybdate is (1.7~3.5):1. This molar ratio is beneficial to improving the adsorption effect of metal-organic framework microcapsules on perfluorohexanone.

[0014] Preferably, the molar ratio of the organic iron source to hexamethylenetetramine is (0.21~0.3):1. This molar ratio is beneficial to improving the adsorption effect of metal-organic framework microcapsules on perfluorohexanone.

[0015] Preferably, the molar ratio of the organic iron source to polyvinylpyrrolidone is (0.15~0.3):1. This molar ratio is beneficial to improving the adsorption effect of metal-organic framework microcapsules on perfluorohexanone.

[0016] Preferably, the molar ratio of the organic iron source to thioacetamide is (0.4~0.65):1. This molar ratio is beneficial to improving the adsorption effect of metal-organic framework microcapsules on perfluorohexanone.

[0017] Preferably, the iron source for the organic compound is iron acetylacetonate. Iron acetylacetonate is more conducive to improving the adsorption effect of metal-organic framework microcapsules on perfluorohexanone.

[0018] This invention also protects a perfluorohexanone fire extinguishing microcapsule, comprising a core and a shell, wherein the core is perfluorohexanone and the shell is a metal-organic framework microcapsule as described in any of the above claims.

[0019] The present invention also protects the preparation method of the above-mentioned perfluorohexanone fire extinguishing microcapsules, comprising the following steps: mixing and adsorbing the metal-organic framework microcapsules described in any one of the above claims with perfluorohexanone to obtain the perfluorohexanone fire extinguishing microcapsules.

[0020] This invention also protects the application of the above-mentioned perfluorohexanone fire extinguishing microcapsules in the preparation of fire extinguishing microcapsule slurry, fire extinguishing patches, flame-retardant cloth, and fire-retardant coatings.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention discloses a metal-organic framework microcapsule, which is prepared by hydrothermal reaction of an organic iron source, trimesic acid, hexamine molybdate, hexamethylenetetramine, polyvinylpyrrolidone, and thioacetamide. When the metal-organic framework microcapsule of the present invention is used as the shell of a perfluorohexanone fire extinguishing microcapsule, it can reduce the response temperature, achieve the effect of releasing perfluorohexanone starting at 90°C and completely releasing perfluorohexanone at 100~110°C, and can quickly trigger fire extinguishing in the early stage of a fire. Moreover, it has an excellent adsorption effect on perfluorohexanone, and a smaller number of fire extinguishing microcapsules are needed to complete the fire extinguishing. In addition, after the perfluorohexanone is completely released, it can be repeatedly adsorbed, realizing multiple reuses. Attached Figure Description

[0022] Figure 1 This is a photograph of the perfluorohexanone fire extinguishing microcapsules from Example 1. Detailed Implementation

[0023] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0024] Iron acetylacetone, abbreviated as Fe(acac)3, has the CAS number 14024-18-1.

[0025] Iron hexafluoroacetylacetonate, abbreviated as Fe(hfac)3, has the CAS number 17786-67-3.

[0026] Ferrous acetylacetone, abbreviated as Fe(acac)2, has the CAS number 14024-17-0.

[0027] Iron trifluoroacetylacetonate, abbreviated as Fe(tfac)3, has the CAS number 14526-22-8.

[0028] Iron benzoyl acetone, abbreviated as Fe(bzac)3, has the CAS number 14323-17-2.

[0029] Ruthenium acetylacetonate, abbreviated as Ru (acac)3, has the CAS number 14284-93-6.

[0030] Cobalt acetylacetonate, abbreviated as Co (acac)3, has the CAS number 21679-46-9.

[0031] Aluminum acetylacetonate, abbreviated as Al(acac)3, has the CAS number 13963-57-0.

[0032] Hexamine molybdate tetrahydrate, chemical formula (NH4)6Mo7O 24 • 4H2O, CAS number 12054-85-2.

[0033] Tris(2-pyromellitic acid), abbreviated as H3BTC, has the CAS number 554-95-0.

[0034] Hexamethylenetetramine, CAS number 100-97-0.

[0035] Polyvinylpyrrolidone, manufactured by Anaiji, product number A050756, with a number-average molecular weight of 111 g / mol.

[0036] Thioacetamide, CAS number 62-55-5.

[0037] Example 1 A metal-organic framework microcapsule, the preparation method of which includes the following steps: 100.0 mL of acetylacetone iron (15 mg / mL, N,N-dimethylformamide) as the organic iron source, 12.0 mL of hexamine molybdate tetrahydrate (150 mg / mL, water), 25.0 mL of trimesic acid (60 mg / mL, N,N-dimethylformamide), 50.0 mL of polyvinylpyrrolidone (40 mg / mL, N,N-dimethylformamide), 100 mL of hexamethylenetetramine (20 mg / mL, ethanol), and 25.0 mL of thioacetamide (20 mg / mL, N,N-dimethylformamide) were added to 500 mL of N,N-dimethylformamide. The mixture was stirred at room temperature for half an hour to obtain a homogeneous solution. The homogeneous solution was then transferred to a 2 L stainless steel autoclave lined with polytetrafluoroethylene for hydrothermal reaction, and heated at 180°C with stirring for 12 h. The product was centrifuged at 10,000 Rpm and then purified and dried with ethanol multiple times to obtain 10.0 g of metal-organic framework microcapsules. The molar ratio of the organic iron source to pyromellitic acid is 0.6:1. The molar ratio of the organic iron source to hexamine molybdate is 2.92 : 1; The molar ratio of the organic iron source to hexamethylenetetramine is 0.3:1; The molar ratio of the organic iron source to polyvinylpyrrolidone is 0.24:1; The molar ratio of the organic iron source to thioacetamide is 0.64:1.

[0038] A perfluorohexanone fire extinguishing microcapsule includes a core and a shell, wherein the core is perfluorohexanone and the shell is the aforementioned metal-organic framework microcapsule.

[0039] The preparation method of the above-mentioned perfluorohexanone fire extinguishing microcapsules includes the following steps: immersing 10.0 g of the above-mentioned metal-organic framework microcapsules in 200.0 g of perfluorohexanone, so that the metal-organic framework microcapsules and perfluorohexanone are mixed and adsorbed, thereby obtaining the perfluorohexanone fire extinguishing microcapsules.

[0040] Example 2 A metal-organic framework microcapsule was prepared in a manner different from that in Example 1, in which ferric acetylacetone was replaced with 191.7 ml of ferric hexafluoroacetylacetone (concentration of 15 mg / ml, solvent of N,N-dimethylformamide), which is the same molar amount as ferric acetylacetone in Example 1.

[0041] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0042] Examples 3-6 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that 25.0 mL of trimellitic acid solvent was replaced with 35.0, 30.0, 20.0, and 15.0 mL of trimellitic acid solvent, respectively, so that the molar ratio of acetylacetone iron to trimellitic acid was 0.43:1, 0.50:1, 0.74:1, and 0.99:1, respectively.

[0043] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0044] Examples 7-12 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that 12.0 mL of hexamine molybdate tetrahydrate solvent was replaced with 20.0, 15.0, 10.0, 8.0, 6.0, and 4.0 mL of hexamine molybdate tetrahydrate solvent, so that the molar ratio of acetylacetone iron to hexamine molybdate tetrahydrate was 1.75:1, 2.33:1, 3.50:1, 4.37:1, 5.83:1, and 8.75:1, respectively.

[0045] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0046] Examples 13-18 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that 50.0 mL of polyvinylpyrrolidone solvent was replaced with 80.0, 70.0, 60.0, 40.0, 30.0, and 20.0 mL of polyvinylpyrrolidone solvent, respectively, so that the molar ratio of acetylacetone iron to polyvinylpyrrolidone was 0.15:1, 0.17:1, 0.20:1, 0.30:1, 0.39:1, and 0.59:1.

[0047] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0048] Examples 19-23 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that 100.0 mL of hexamethylenetetramine solvent was replaced with 140.0, 120.0, 80.0, 60.0, and 40.0 mL of hexamethylenetetramine solvent, so that the molar ratio of acetylacetone iron to hexamethylenetetramine was 0.21:1, 0.25:1, 0.37:1, 0.50:1, and 0.74:1, respectively.

[0049] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0050] Examples 24-28 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that 25.0 ml of thioacetamide solvent was replaced with 40.0, 30.0, 20.0, 15.0, and 10.0 ml of thioacetamide solvent, respectively, so that the molar ratio of acetylacetone iron to thioacetamide was 0.40:1, 0.53:1, 0.80:1, 1.06:1, and 1.60:1, respectively.

[0051] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0052] Examples 29-30 The preparation method of a metal-organic framework microcapsule differs from that of Example 1 in that the hydrothermal reaction temperatures are 120.0℃ and 240.0℃, respectively.

[0053] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0054] Examples 31-32 The preparation method of a metal-organic framework microcapsule differs from that of Example 1 in that the hydrothermal reaction time is 8.0 h and 24.0 h, respectively.

[0055] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0056] Comparative Example 1 A metal-organic framework microcapsule was prepared in a manner different from that in Example 1, in which ferric acetylacetone was replaced with 112.8 ml of ruthenium acetylacetone (concentration of 15 mg / ml, solvent of N,N-dimethylformamide), which is the same molar amount as ferric acetylacetone in Example 1.

[0057] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0058] Comparative Example 2 A metal-organic framework microcapsule was prepared in a manner different from that in Example 1, in which iron acetylacetonate was replaced with 91.8 ml of aluminum acetylacetonate (concentration of 15 mg / ml, solvent of N,N-dimethylformamide), with the same molar amount of iron acetylacetonate as in Example 1.

[0059] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0060] Comparative Example 3 A metal-organic framework microcapsule was prepared in a manner different from that in Example 1, in which iron acetylacetone was replaced with 100.9 ml of cobalt acetylacetone (concentration of 15 mg / ml, solvent of N,N-dimethylformamide), with the same molar amount of iron acetylacetone as in Example 1.

[0061] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0062] Comparative Example 4 A metal-organic framework microcapsule was prepared in a manner different from that in Example 1, in which ferric acetylacetone was replaced with 71.9 ml of ferrous acetylacetone (concentration of 15 mg / ml, solvent of N,N-dimethylformamide), which is the same molar amount as ferric acetylacetone in Example 1.

[0063] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0064] Comparative Example 5 A metal-organic framework microcapsule was prepared in a manner different from that in Example 1, in which ferric acetylacetone was replaced with 145.8 ml of ferric trifluoroacetylacetone (concentration of 15 mg / ml, solvent of N,N-dimethylformamide), which is the same molar amount of ferric acetylacetone as in Example 1.

[0065] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0066] Comparative Example 6 A metal-organic framework microcapsule was prepared in a manner different from that in Example 1, in which ferric acetylacetone was replaced with 152.7 ml of ferric benzoylacetone (concentration of 15 mg / ml, solvent of N,N-dimethylformamide), which is the same molar amount as ferric acetylacetone in Example 1.

[0067] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0068] Comparative Example 7 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that 25.0 mL of trimellitic acid solvent was replaced with 10.0 mL of trimellitic acid solvent, so that the molar ratio of acetylacetone iron to trimellitic acid was 1.49:1.

[0069] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0070] Comparative Example 8 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that 100.0 mL of hexamethylenetetramine solvent was replaced with 20.0 mL of hexamethylenetetramine solvent, so that the molar ratio of acetylacetone iron to hexamethylenetetramine was 1.49:1.

[0071] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0072] Comparative Example 9 A metal-organic framework microcapsule was prepared in a method that differed from that in Example 1 in that the hydrothermal reaction temperature was 60.0 °C.

[0073] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0074] Comparative Example 10 The preparation method of a metal-organic framework microcapsule differs from that of Example 1 in that the hydrothermal reaction time is 6.0 h.

[0075] A perfluorohexanone fire extinguishing microcapsule was prepared using the same method as in Example 1.

[0076] Performance testing (1) Perfluorohexanone adsorption capacity test: The weight of the perfluorohexanone fire extinguishing microcapsule of Example 1 was weighed, which was 44.7g. That is, the weight of the capsule shell was 10g, and the weight of perfluorohexanone was 34.7g. The maximum perfluorohexanone adsorption capacity of the perfluorohexanone fire extinguishing microcapsule of Example 1 was 3.47 g (perfluorohexanone) / g (microcapsule). The maximum perfluorohexanone adsorption capacity of the perfluorohexanone fire extinguishing microcapsules of each example and comparative example was tested in the same way. The test results are shown in Table 1 below.

[0077] Table 1

[0078] Continued from Table 1

[0079] Continued from Table 1

[0080] Continued from Table 1

[0081] As can be seen from Table 1 above, the perfluorohexanone fire extinguishing microcapsules of the present invention have a high adsorption capacity for perfluorohexanone, with an adsorption capacity of 1.97~3.47 g (perfluorohexanone) / g (microcapsule).

[0082] In practical applications, 100g of the metal-organic framework microcapsules from each embodiment and comparative example of this invention were used to prepare perfluorohexanone fire extinguishing microcapsules after adsorbing perfluorohexanone. These microcapsules were then used to prepare fire extinguishing patches with dimensions of 500 × 400 mm. These patches were then affixed to the upper surface of a 950 × 500 × 170 mm electrical meter box. A fire was ignited using the same method, triggering the perfluorohexanone fire extinguishing microcapsules to extinguish the fire. Testing showed that the perfluorohexanone fire extinguishing microcapsules from each embodiment of this invention could extinguish the fire within 5 seconds. Temperatures exceeding 5 seconds would adversely affect the equipment and fail to meet practical requirements.

[0083] The perfluorohexanone fire extinguishing microcapsules in Comparative Examples 2 to 10 were unable to extinguish the fire within 5 seconds. This is because the effective content of perfluorohexanone in the microcapsules of Comparative Examples 2 to 10 was insufficient. In addition, due to the limited space of the meter box and the influence of the circuit, it was not possible to use an infinitely large fire extinguishing sticker in the meter box. Therefore, the perfluorohexanone fire extinguishing microcapsules in Comparative Examples 2 to 10 could not extinguish the fire within 5 seconds and could not meet the needs of practical application.

[0084] The microcapsules in Comparative Example 2 showed poor adsorption capacity for perfluorohexanone. This may be because the aluminum-based MOF microcapsules formed by aluminum acetylacetonate have a hydrophilic framework structure with a high proportion of hydrophilic sites on their surface and within the pores, while perfluorohexanone is a strongly hydrophobic fluorinated compound. There is a significant difference in interfacial compatibility between the two, and the adsorption forces such as van der Waals forces and hydrophobic interactions between molecules are extremely weak. Furthermore, the coordination radius of aluminum ions is small, resulting in smaller MOF pore sizes that are difficult to accommodate perfluorohexanone molecules. At the same time, the pore volume and specific surface area of ​​the aluminum-based MOF are much lower than those of the iron-based MOF, further limiting the loading and adsorption of perfluorohexanone.

[0085] The microcapsules in Comparative Example 3 showed poor adsorption capacity for perfluorohexanone. This may be because the coordination and binding mode of cobalt ions and organic ligands in the cobalt-based MOF microcapsule framework formed by cobalt acetylacetone is a low-dimensional chain structure, which makes it difficult to form a three-dimensional porous cage structure. This results in incomplete development of the microcapsule's pore structure and very few effective adsorption sites. Furthermore, there is no specific interaction between the cobalt-based MOF and perfluorohexanone. At the same time, the electron cloud distribution characteristics of cobalt ions make their electrostatic adsorption effect on perfluorohexanone molecules negligible, making it impossible to achieve effective adsorption and loading of perfluorohexanone, ultimately resulting in extremely low adsorption capacity.

[0086] (2) Response temperature test: The perfluorohexanone fire extinguishing microcapsules of Example 1 were divided into 11 groups, namely Group 1, Group 2, ..., Group 11, with 44.7g in each group. Group 1 was kept at 30°C for 5 minutes, Group 2 at 40°C for 5 minutes, ..., Group 11 at 130°C for 5 minutes. After 5 minutes, the weight was measured. The test results are shown in Table 2.

[0087] Table 2

[0088] As shown in Table 2 above, groups 1 through 6 show that the weight of the perfluorohexanone fire extinguishing microcapsules remains unchanged within the temperature range of 30–80°C, indicating that no perfluorohexanone is released from the microcapsules. Group 7 shows that the perfluorohexanone fire extinguishing microcapsules begin to lose weight at 90°C, indicating that perfluorohexanone begins to be released. Group 9 shows that the weight of the perfluorohexanone fire extinguishing microcapsules is only 10g, indicating that all the perfluorohexanone in the microcapsules was released instantaneously at 110°C. This demonstrates that the response temperature of the perfluorohexanone fire extinguishing microcapsules in Example 1 is 110°C.

[0089] The response temperatures of each embodiment and Comparative Example 1 were tested using the same test method, and the test results are shown in Table 3 below.

[0090] Table 3

[0091] The response temperature of the perfluorohexanone fire extinguishing microcapsules in Examples 3 to 32 is close to that in Example 1.

[0092] In practical applications, the lower response temperature facilitates the rapid release of fire extinguishing microcapsules in the early stages of a fire, enabling timely extinguishing of the fire source, blocking the spread of the fire, and significantly reducing the risk of the fire developing and expanding. At the same time, it can reduce the thermal damage to surrounding substrates and equipment caused by high temperatures, improve the safety and efficiency of fire extinguishing operations, and is suitable for various scenarios with high requirements for fire response speed.

[0093] In Example 2, the hexafluoroacetylacetone iron-based perfluorohexanone fire extinguishing microcapsules began to respond at a reaction temperature of 90°C, releasing perfluorohexanone. At 100°C, all the perfluorohexanone in the microcapsules was released instantaneously. The response temperature avoided the 30-80°C temperature rise range of the equipment's normal operation, preventing ineffective release of the fire extinguishing microcapsules. It could quickly trigger fire extinguishing in the early stages of a fire, and its adsorption capacity also met the core requirements for the encapsulation and release of the fire extinguishing microcapsules. Therefore, it was suitable for use as a fire extinguishing material. However, the adsorption capacity of the perfluorohexanone fire extinguishing microcapsules in Example 2 was not as good as that in Example 1, requiring more material to achieve the same fire extinguishing effect. The reason may be that the fluorinated ligands of hexafluoroacetylacetone iron have a strong electron-withdrawing effect and greater steric hindrance, making the coordination bond energy between Fe ions and trimesic acid slightly lower than that of the acetylacetone iron-based microcapsules, resulting in slightly weaker skeletal thermal stability.

[0094] In Comparative Example 1, the perfluorohexanone fire extinguishing microcapsules began to lose weight at 50°C, and by 60°C, all the perfluorohexanone within the microcapsules had been released. In practical applications, the response temperature of perfluorohexanone is too low, making it unsuitable as a fire extinguishing microcapsule material. As can be seen from the examples and Comparative Example 1, although the microcapsules of Comparative Example 1 exhibit excellent adsorption capacity for perfluorohexanone, the release of perfluorohexanone at 50°C indicates a release temperature that is too low for its suitability as a fire extinguishing microcapsule material. This may be because the interaction bond energy between the ruthenium acetylacetonate metal-organic framework microcapsule skeleton and perfluorohexanone is low, and the crystalline structure of ruthenium-based MOF has weak thermal stability. At a mild temperature of 50°C, the pore structure of the skeleton becomes slightly relaxed, and the adsorption force on perfluorohexanone is insufficient to restrain its molecular motion, resulting in the premature release of perfluorohexanone. At the same time, the coordination bond strength of ruthenium ions is lower than that of iron ions, which significantly reduces the thermal response threshold of the microcapsule shell, making it impossible to meet the stable storage requirements of fire extinguishing microcapsules at room temperature and under ambient temperature rise.

[0095] (3) Stability test: The perfluorohexanone fire extinguishing microcapsules of Example 1 were divided into 4 groups, namely Group 12, Group 13, and Group 14, with 44.7g in each group. Group 12 weighed 44.7g after being stored at 30°C for 30 days. Group 13 weighed 44.7g after being stored at 50°C for 30 days. Group 14 weighed 10g after being stored at 80°C for 17 days, with a weight loss of 34.7g.

[0096] As can be seen from Groups 12 and 13 above, the weight of the perfluorohexanone fire extinguishing microcapsules in Example 1 remains unchanged under the condition of 30~50℃, indicating that the perfluorohexanone fire extinguishing microcapsules can be stably stored under the condition of 30~50℃ without leakage.

[0097] The perfluorohexanone fire extinguishing microcapsules of Examples 2-32 can be stably stored at 30-50°C.

[0098] (4) The microcapsules from groups 1 to 9 of Example 1, which had completely released perfluorohexanone, were re-added to 200.0 g of perfluorohexanone. After adsorbing the perfluorohexanone, new perfluorohexanone fire extinguishing microcapsules were obtained, and the weight of the perfluorohexanone fire extinguishing microcapsules after adsorption was tested. The perfluorohexanone fire extinguishing microcapsules of each group were again kept at 110°C for 5 minutes, and weighed after 5 minutes. This test was repeated until the adsorption capacity of the perfluorohexanone fire extinguishing microcapsules for perfluorohexanone began to decrease. The test results showed that after the perfluorohexanone fire extinguishing microcapsules of Example 1 were reused six times, the adsorption capacity of perfluorohexanone showed a significant decrease.

[0099] After the perfluorohexanone fire extinguishing microcapsules in Example 2 were reused five times, the adsorption capacity of perfluorohexanone showed a significant decrease.

[0100] The test results above show that the perfluorohexanone fire extinguishing microcapsules of the present invention have a high adsorption capacity for perfluorohexanone, with an adsorption capacity of 1.97~3.47g (perfluorohexanone) / g (microcapsule). They can be stored for a long time at room temperature of 30~50℃, and can release perfluorohexanone at a temperature of 100~110℃. Moreover, after the perfluorohexanone is completely released, it can be repeatedly adsorbed, realizing multiple reuses.

[0101] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A metal-organic framework microcapsule, characterized in that, The metal-organic framework microcapsules are prepared by the following method: an organic iron source, trimesic acid, hexamine molybdate, hexamethylenetetramine, polyvinylpyrrolidone, and thioacetamide are mixed and reacted hydrothermally to obtain the metal-organic framework microcapsules. The iron source of the organism is iron acetylacetone and / or iron hexafluoroacetylacetone; The molar ratio of the organic iron source to trimesic acid is (0.4~1):1; The molar ratio of the organic iron source to hexamine molybdate is (1~9):1; The molar ratio of the organic iron source to hexamethylenetetramine is (0.2~0.8):1; The molar ratio of the organic iron source to polyvinylpyrrolidone is (0.1~0.6):1; The molar ratio of the organic iron source to thioacetamide is (0.4~1.7):1; The hydrothermal reaction temperature is 120~240 ℃, and the hydrothermal reaction time is 8~24 h.

2. The metal-organic framework microcapsule according to claim 1, characterized in that, The molar ratio of the organic iron source to pyromellitic acid is (0.43~0.62):

1.

3. The metal-organic framework microcapsule according to claim 1, characterized in that, The molar ratio of the organic iron source to hexamine molybdate is (1.7~3.5):

1.

4. The metal-organic framework microcapsule according to claim 1, characterized in that, The molar ratio of the organic iron source to hexamethylenetetramine is (0.21~0.3):

1.

5. The metal-organic framework microcapsule according to claim 1, characterized in that, The molar ratio of the organic iron source to polyvinylpyrrolidone is (0.15~0.3):

1.

6. The metal-organic framework microcapsule according to claim 1, characterized in that, The molar ratio of the organic iron source to thioacetamide is (0.4~0.65):

1.

7. The metal-organic framework microcapsule according to claim 1, characterized in that, The iron source for the organism is iron acetylacetone.

8. A perfluorohexanone fire extinguishing microcapsule, characterized in that, It includes a core and a shell, wherein the core is perfluorohexanone and the shell is a metal-organic framework microcapsule as described in any one of claims 1 to 7.

9. The method for preparing the perfluorohexanone fire extinguishing microcapsule according to claim 8, comprising the following steps: mixing and adsorbing the metal-organic framework microcapsule according to any one of claims 1 to 7 with perfluorohexanone to obtain the perfluorohexanone fire extinguishing microcapsule.

10. The application of the perfluorohexanone fire extinguishing microcapsules according to claim 8 in the preparation of fire extinguishing microcapsule slurry, fire extinguishing patches, flame retardant cloth, and fireproof coatings.

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