Heptafluoropropane fire extinguishing agent and preparation method thereof

Abstract

The invention provides a heptafluoropropane fire extinguishing agent and a preparation method thereof, and belongs to the technical field of fire fighting, and the preparation method comprises the following steps: step S1, calcium fluoride nanoparticles are added into absolute ethyl alcohol, after complete dispersion, ZIF-8 is added, ultrasonic treatment, standing, filtering and drying are performed, and ZIF-8 loaded with calcium fluoride is obtained; s2, putting tris (tribromophenoxy) triazine into a crusher for crushing, then adding gas-phase nano silicon dioxide, and carrying out dry mixing, so as to obtain composite powder; and S3, perfluorohexanone and a perfluoropolyether-based surfactant are mixed and continuously stirred, modified nano SiO2 and ZIF-8 loaded with calcium fluoride are sequentially added, high-speed shearing is conducted, finally, the composite powder is added, the mixture is mixed to be uniform and then mixed with heptafluoropropane, and the heptafluoropropane fire extinguishing agent is obtained. The purposes of efficient fire extinguishing and pollution reduction of the heptafluoropropane fire extinguishing agent can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of fire fighting, and in particular to a heptafluoropropane fire extinguishing agent and a preparation method thereof. Background Art

[0002] Halon and chlorofluorocarbon fire extinguishing agents were once widely used in specialized environments, such as electronic equipment rooms, cultural relic protection sites, and ships and aircraft, due to their rapid fire extinguishing, low toxicity, long shelf life, and safety against the objects being protected. However, their chemical stability makes them difficult to decompose in the stratosphere. The chlorine and bromine radicals released by ultraviolet radiation can catalyze the decomposition of nearly 100,000 times more ozone molecules, causing ozone layer depletion. Therefore, developing environmentally friendly alternatives has become a research focus in the firefighting field.

[0003] Currently, transitional alternatives, such as heptafluoropropane (HFC-227ea) and hexafluoropropane (HFC-236fa), hold a 70% market share due to their similar physical and chemical properties to halons and an ozone depletion potential (ODP ≈ 0). These gases disrupt the combustion chain reaction through gas-phase diffusion, making them suitable for use in applications such as precision instruments and data centers. However, at high temperatures (>400°C), heptafluoropropane and hexafluoropropane decompose to produce toxic byproducts such as hydrogen fluoride (HF) and carbon monoxide. For example, at a fire extinguishing concentration of 10%, heptafluoropropane produces 8-10 times more HF than bromotrifluoromethane, increasing its potential hazards.

[0004] Patent application publication number CN106621158A discloses a highly effective heptafluoropropane-based fire extinguishing agent. The raw materials, by weight percentage, include: 35-45% heptafluoropropane, 10-14% dry ice, 6-10% sodium dihydrogen phosphate, 8-12% sodium carbonate, 6-10% sodium acetate trihydrate, 8-12% sodium chloride, 1-3% carbonamide, and 8-12% water. The sodium dihydrogen phosphate, sodium carbonate, sodium acetate trihydrate, sodium chloride, carbonamide, and water are mixed and stirred according to the above proportions to produce a mixture. The heptafluoropropane is pressurized to produce liquid heptafluoropropane. Dry ice is added according to the proportions, and the mixture is uniformly mixed and loaded into a fire extinguishing device to produce the fire extinguishing agent. The fire extinguishing agent prepared by this method still has insufficient fire extinguishing efficiency. Furthermore, harmful gases such as HF generated during heptafluoropropane fire extinguishing are only absorbed to a limited extent, making it difficult to achieve efficient fire extinguishing and reduce pollution.

[0005] Therefore, it is necessary to provide a preparation method of heptafluoropropane fire extinguishing agent to solve the problems existing in the above-mentioned prior art. Summary of the Invention

[0006] In view of this, the present invention provides a heptafluoropropane fire extinguishing agent and a preparation method thereof, which can achieve the purpose of highly efficient fire extinguishing with the heptafluoropropane fire extinguishing agent and reduce pollution.

[0007] The specific scheme of the present invention is as follows: a method for preparing a heptafluoropropane fire extinguishing agent, comprising the following steps: Step S1, adding calcium fluoride nanoparticles to anhydrous ethanol, and after completely dispersing, adding ZIF-8, ultrasonically treating, standing, filtering, and drying to obtain ZIF-8 loaded with calcium fluoride; Step S2, putting tris(tribromophenoxy)triazine into a grinder for grinding, then adding fumed nano-silica, and dry-mixing to obtain a composite powder; Step S3: perfluorohexanone and a perfluoropolyether-based surfactant are mixed, and the mixture is continuously stirred. Modified nano-SiO2 and calcium fluoride-loaded ZIF-8 are added in sequence, and sheared at high speed. Finally, the composite powder is added, mixed evenly, and then mixed with heptafluoropropane to obtain a heptafluoropropane fire extinguishing agent.

[0008] ZIF-8, synthesized using 2-methylimidazole and zinc nitrate via a solvothermal method, has a zeolitic imidazolate framework and a high specific surface area. Its microporous structure efficiently adsorbs free radicals and toxic gases produced by combustion, reducing the flame chain reaction rate and effectively improving the fire extinguishing agent's effectiveness. Furthermore, ZIF-8 remains stable below 550°C, maintaining its effectiveness in the initial stages of a fire.

[0009] Calcium fluoride is embedded into the ZIF-8 pores and surface through ultrasonic dispersion. After loading calcium fluoride, the porous structure of ZIF-8 can avoid calcium fluoride agglomeration and achieve controlled release of fluoride ions. In addition, ZIF-8 can decompose Zn at high temperature. 2+ , which is consistent with F - It can combine to form ZnF2, block the formation of HF, and greatly reduce the emission of HF. 2+ and Cl in combustion products - 、SO4 2- Combined to reduce corrosive gas emissions.

[0010] The composite powder is made by mixing tris(tribromophenoxy)triazine with fumed silica. The triazine structure decomposes at 200-300°C, releasing bromine radicals that capture hydrogen and hydroxyl radicals in the combustion chain, achieving cyclic flame retardancy. The SiO2 synergizes with the char layer formed by the decomposition of tris(tribromophenoxy)triazine to form a Si-O-Br cross-linked network, increasing the density of the char layer, blocking heat and oxygen, and improving fire extinguishing efficiency.

[0011] Perfluorohexanone absorbs heat during vaporization, rapidly reducing the fire's temperature. Its high vapor density quickly dilutes oxygen, aiding the fire extinguishing agent's effectiveness. Combined with perfluoropolyether-based surfactants, it reduces the surface tension of droplets, promoting penetration of the extinguishing agent into combustible materials and further interrupting combustion. Heptafluoropropane, a gaseous agent at room temperature, rapidly diffuses within a fire, effectively reducing oxygen concentrations. Furthermore, it forms a gas-liquid two-phase extinguishing system with perfluorohexanone, expanding the extinguishing agent's range of action and suppressing rekindling.

[0012] Preferably, the preparation of ZIF-8 comprises the following steps: dissolving 2-methylimidazole in methanol and mixing uniformly to obtain solution A; dissolving zinc nitrate in methanol, slowly adding solution A, introducing nitrogen, heating in a water bath for reaction, centrifuging, washing, and drying to obtain ZIF-8.

[0013] ZIF-8 was synthesized by solvothermal method using 2-methylimidazole and zinc nitrate in methanol. 2+ ) has Lewis acidity and can catalyze the decomposition of nitrogen / sulfur-containing toxic gases into harmless small molecules, reducing pollution.

[0014] Preferably, the heating reaction temperature is 55-65° C. and the time is 5-7 hours.

[0015] Preferably, in step S2, the particle size of tris(tribromophenoxy)triazine after pulverization is 3-5 μm; and the mass ratio of tris(tribromophenoxy)triazine to fumed nano-silica is (9-12):1.

[0016] Fumed nano-silica can increase viscosity and inhibit the occurrence of dripping of materials during the fire extinguishing process.

[0017] Preferably, in step S3, the preparation of modified nano-SiO2 comprises the following steps: dispersing nano-SiO2 in hexamethyldisilazane, heating and stirring, filtering, washing, and drying to obtain modified nano-SiO2.

[0018] The surface energy of nano-SiO2 after hydrophobic modification is reduced, which can prevent it from agglomerating in non-polar solvents and ensure that the nanoparticles are evenly dispersed.

[0019] Preferably, the heating and stirring temperature is 55-65° C. and the time is 4-6 hours.

[0020] Preferably, the drying temperature is 60-70° C. and the drying time is 10-14 hours.

[0021] Preferably, in step S3, the stirring speed is continuously 150-250 rpm.

[0022] Preferably, in step S3, zinc borate is added before sequentially adding modified nano-SiO2 and ZIF-8 loaded with calcium fluoride, and ultrasonically dispersed.

[0023] Zinc borate can decompose at high temperatures to form B2O3 glass, which covers the surface of combustible materials, isolates oxygen, and blocks combustion. The crystal water released can absorb heat and cool down, and the water vapor can dilute the oxygen concentration and enhance the fire extinguishing effect of the fire extinguishing agent.

[0024] To achieve the above object, the present invention further provides a heptafluoropropane fire extinguishing agent prepared by the above method for preparing a heptafluoropropane fire extinguishing agent, characterized in that it comprises the following components in parts by weight: 15-20 parts of perfluorohexanone, 0.05-0.1 parts of perfluoropolyether-based surfactant, 0.3-0.8 parts of modified nano-SiO2, 2-3 parts of ZIF-8 loaded with calcium fluoride, 0.5-1.5 parts of composite powder and 70-80 parts of heptafluoropropane.

[0025] The present invention adopts the above components in parts by weight to enable the heptafluoropropane fire extinguishing agent to achieve high-efficiency fire extinguishing and reduce pollution.

[0026] Preferably, the following components in parts by weight are also included: 0.2-0.5 parts of zinc borate; Preferably, the composite powder comprises the following raw materials in parts by weight: 9-18 parts of tris(tribromophenoxy)triazine and 1-1.5 parts of fumed nano-silica.

[0027] Preferably, the ZIF-8 loaded with calcium fluoride comprises the following raw materials in parts by weight: 2-4 parts of calcium fluoride and 8-16 parts of ZIF-8.

[0028] The above technical solution of the present invention includes at least the following beneficial effects: (1) ZIF-8 has a zeolite imidazolate skeleton structure and a high specific surface area. Its microporous structure can efficiently adsorb free radicals and toxic gases produced by combustion, reduce the flame chain reaction rate, and effectively improve the fire extinguishing efficiency of the fire extinguishing agent. After loading with calcium fluoride, the pore structure of ZIF-8 can achieve controlled release of fluoride ions, prolonging the action time of the fire extinguishing agent, and Ca 2+ Can react with Cl in combustion products - 、SO4 2- It combines with other corrosive ions to reduce the emission of corrosive gases and reduce pollution.

[0029] (2) The triazine structure in the composite powder decomposes at high temperatures, releasing bromine free radicals that capture hydrogen free radicals and hydroxyl free radicals in the combustion chain, achieving flame retardancy and fire extinguishing. Nano-silica can synergistically form a Si-O-Br cross-linked network with the char layer formed by the decomposition of tris(tribromophenoxy)triazine, improving the density of the char layer, blocking heat and oxygen, and further improving fire extinguishing efficiency.

[0030] (3) Perfluorohexanone can quickly reduce the temperature of the fire scene, and its high vapor density forms a gas-liquid two-phase fire extinguishing system with heptafluoropropane, which can quickly dilute oxygen and help the fire extinguishing agent to exert its fire extinguishing effect. In addition, perfluorohexanone combined with perfluoropolyether-based surfactants can reduce the surface tension of the droplets, promote the penetration of the fire extinguishing agent into the combustible material, and further block the combustion. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are only part of the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0032] Example 1 Dissolve 12 g of 2-methylimidazole in 200 mL of methanol and mix well to obtain solution A. Dissolve 8 g of zinc nitrate in 200 mL of methanol and slowly add solution A. Heat to 65°C in a water bath, introduce nitrogen, react for 5 h, centrifuge, wash, and dry to obtain ZIF-8.

[0033] 4 g of calcium fluoride nanoparticles were added to 200 mL of anhydrous ethanol and dispersed to form a suspension. 16 g of ZIF-8 was added and ultrasonicated for 2 h. The suspension was allowed to stand, filtered, and dried to obtain ZIF-8 loaded with calcium fluoride.

[0034] 9 g of tris(tribromophenoxy)triazine was put into a grinder and ground into 3-5 μm, 1 g of fumed nano-silica was added, and dry-mixed to obtain a composite powder.

[0035] Disperse 1 g of nano-SiO2 in a beaker containing 20 mL of hexamethyldisilazane, place the beaker in a water bath, heat to 65°C, stir and react for 4 hours, filter, wash three times with anhydrous ethanol, and vacuum dry at 60°C for 14 hours to obtain modified nano-SiO2.

[0036] Mix 18g of perfluorohexanone with 0.08g of perfluoropolyether-based surfactant, continue stirring, add 0.35g of zinc borate, and ultrasonically disperse. Then, add 0.6g of modified nano-SiO2 and 2g of ZIF-8 loaded with calcium fluoride in sequence, shear at high speed, add 1g of composite powder, stir evenly, and mix with 75g of heptafluoropropane to obtain heptafluoropropane fire extinguishing agent.

[0037] Example 2 Dissolve 12 g of 2-methylimidazole in 200 mL of methanol and mix well to obtain solution A. Dissolve 8 g of zinc nitrate in 200 mL of methanol and slowly add solution A. Heat to 60°C in a water bath, introduce nitrogen, react for 6 h, centrifuge, wash, and dry to obtain ZIF-8.

[0038] 3 g of calcium fluoride nanoparticles were added to 150 mL of anhydrous ethanol and dispersed to form a suspension. 12 g of ZIF-8 was added and ultrasonicated for 2 h. The suspension was allowed to stand, filtered, and dried to obtain ZIF-8 loaded with calcium fluoride.

[0039] 9 g of tris(tribromophenoxy)triazine was put into a grinder and ground into 3-5 μm, 1 g of fumed nano-silica was added, and dry-mixed to obtain a composite powder.

[0040] Disperse 1 g of nano-SiO2 in a beaker containing 20 mL of hexamethyldisilazane, place the beaker in a water bath, heat to 55°C, stir and react for 6 hours, filter, wash three times with anhydrous ethanol, and vacuum dry at 70°C for 10 hours to obtain modified nano-SiO2.

[0041] Mix 15g of perfluorohexanone with 0.05g of perfluoropolyether-based surfactant, continue stirring, add 0.5g of zinc borate, and ultrasonically disperse. Then, add 0.3g of modified nano-SiO2 and 3g of ZIF-8 loaded with calcium fluoride in sequence, shear at high speed, add 1.5g of composite powder, stir evenly, and mix with 70g of heptafluoropropane to obtain heptafluoropropane fire extinguishing agent.

[0042] Example 3 Dissolve 12 g of 2-methylimidazole in 200 mL of methanol and mix well to obtain solution A. Dissolve 8 g of zinc nitrate in 200 mL of methanol and slowly add solution A. Heat to 55°C in a water bath, introduce nitrogen, react for 7 h, centrifuge, wash, and dry to obtain ZIF-8.

[0043] 2 g of calcium fluoride nanoparticles were added to 100 mL of anhydrous ethanol and dispersed to form a suspension. 8 g of ZIF-8 was added and ultrasonicated for 2 h. The suspension was allowed to stand, filtered, and dried to obtain ZIF-8 loaded with calcium fluoride.

[0044] 18 g of tris(tribromophenoxy)triazine was put into a grinder and ground into 3-5 μm, 1.5 g of fumed nano-silica was added, and dry-mixed to obtain a composite powder.

[0045] Disperse 1 g of nano-SiO2 in a beaker containing 20 mL of hexamethyldisilazane, place the beaker in a water bath, heat to 60°C, stir and react for 5 hours, filter, wash three times with anhydrous ethanol, and vacuum dry at 65°C for 12 hours to obtain modified nano-SiO2.

[0046] Mix 20g of perfluorohexanone with 0.1g of perfluoropolyether-based surfactant, continue stirring, add 0.2g of zinc borate, and ultrasonically disperse. Then, add 0.8g of modified nano-SiO2 and 2.5g of ZIF-8 loaded with calcium fluoride in sequence, shear at high speed, add 1g of composite powder, stir evenly, and mix with 75g of heptafluoropropane to obtain heptafluoropropane fire extinguishing agent.

[0047] Example 4 Dissolve 12 g of 2-methylimidazole in 200 mL of methanol and mix well to obtain solution A. Dissolve 8 g of zinc nitrate in 200 mL of methanol and slowly add solution A. Heat to 60°C in a water bath, introduce nitrogen, react for 5.5 h, centrifuge, wash, and dry to obtain ZIF-8.

[0048] 3 g of calcium fluoride nanoparticles were added to 150 mL of anhydrous ethanol and dispersed to form a suspension. 12 g of ZIF-8 was added and ultrasonicated for 2 h. The suspension was allowed to stand, filtered, and dried to obtain ZIF-8 loaded with calcium fluoride.

[0049] 9 g of tris(tribromophenoxy)triazine was put into a grinder and ground into 3-5 μm, 1 g of fumed nano-silica was added, and dry-mixed to obtain a composite powder.

[0050] Disperse 1 g of nano-SiO2 in a beaker containing 20 mL of hexamethyldisilazane, place the beaker in a water bath, heat to 55°C, stir and react for 6 hours, filter, wash three times with anhydrous ethanol, and vacuum dry at 60°C for 14 hours to obtain modified nano-SiO2.

[0051] Mix 18g of perfluorohexanone with 0.1g of perfluoropolyether-based surfactant, continue stirring, add 0.4g of zinc borate, and ultrasonically disperse. Then, add 0.5g of modified nano-SiO2 and 2g of ZIF-8 loaded with calcium fluoride in sequence, shear at high speed, add 0.5g of composite powder, stir evenly, and mix with 80g of heptafluoropropane to obtain heptafluoropropane fire extinguishing agent.

[0052] Example 5 Dissolve 12 g of 2-methylimidazole in 200 mL of methanol and mix well to obtain solution A. Dissolve 8 g of zinc nitrate in 200 mL of methanol and slowly add solution A. Heat to 55°C in a water bath, introduce nitrogen, react for 6.5 h, centrifuge, wash, and dry to obtain ZIF-8.

[0053] 2 g of calcium fluoride nanoparticles were added to 100 mL of anhydrous ethanol and dispersed to form a suspension. 8 g of ZIF-8 was added and ultrasonicated for 2 h. The suspension was allowed to stand, filtered, and dried to obtain ZIF-8 loaded with calcium fluoride.

[0054] 18 g of tris(tribromophenoxy)triazine was put into a grinder and ground into 3-5 μm, 1.5 g of fumed nano-silica was added, and dry-mixed to obtain a composite powder.

[0055] Disperse 1 g of nano-SiO2 in a beaker containing 20 mL of hexamethyldisilazane, place the beaker in a water bath, heat to 50°C, stir and react for 5.5 hours, filter, wash three times with anhydrous ethanol, and vacuum dry at 60°C for 11 hours to obtain modified nano-SiO2.

[0056] Mix 15g of perfluorohexanone with 0.05g of perfluoropolyether-based surfactant, continue stirring, add 0.5g of zinc borate, and ultrasonically disperse. Then, add 0.6g of modified nano-SiO2 and 2g of ZIF-8 loaded with calcium fluoride in sequence, shear at high speed, add 1g of composite powder, stir evenly, and mix with 75g of heptafluoropropane to obtain heptafluoropropane fire extinguishing agent.

[0057] Example 6 Dissolve 12 g of 2-methylimidazole in 200 mL of methanol and mix well to obtain solution A. Dissolve 8 g of zinc nitrate in 200 mL of methanol and slowly add solution A. Heat to 65°C in a water bath, introduce nitrogen, react for 5.5 h, centrifuge, wash, and dry to obtain ZIF-8.

[0058] 4 g of calcium fluoride nanoparticles were added to 200 mL of anhydrous ethanol and dispersed to form a suspension. 16 g of ZIF-8 was added and ultrasonicated for 2 h. The suspension was allowed to stand, filtered, and dried to obtain ZIF-8 loaded with calcium fluoride.

[0059] 9 g of tris(tribromophenoxy)triazine was put into a grinder and ground into 3-5 μm, 1 g of fumed nano-silica was added, and dry-mixed to obtain a composite powder.

[0060] Disperse 1 g of nano-SiO2 in a beaker containing 20 mL of hexamethyldisilazane, place the beaker in a water bath, heat to 65°C, stir and react for 4.5 hours, filter, wash three times with anhydrous ethanol, and vacuum dry at 65°C for 11 hours to obtain modified nano-SiO2.

[0061] Mix 18g of perfluorohexanone with 0.1g of perfluoropolyether-based surfactant, continue stirring, add 0.3g of zinc borate, and ultrasonically disperse. Then, add 0.5g of modified nano-SiO2 and 3g of ZIF-8 loaded with calcium fluoride in sequence, shear at high speed, add 1.5g of composite powder, stir evenly, and mix with 80g of heptafluoropropane to obtain heptafluoropropane fire extinguishing agent.

[0062] Example 7 Dissolve 12 g of 2-methylimidazole in 200 mL of methanol and mix well to obtain solution A. Dissolve 8 g of zinc nitrate in 200 mL of methanol and slowly add solution A. Heat to 65°C in a water bath, introduce nitrogen, react for 5.5 h, centrifuge, wash, and dry to obtain ZIF-8.

[0063] 4 g of calcium fluoride nanoparticles were added to 200 mL of anhydrous ethanol and dispersed to form a suspension. 16 g of ZIF-8 was added and ultrasonicated for 2 h. The suspension was allowed to stand, filtered, and dried to obtain ZIF-8 loaded with calcium fluoride.

[0064] 9 g of tris(tribromophenoxy)triazine was put into a grinder and ground into 3-5 μm, 1 g of fumed nano-silica was added, and dry-mixed to obtain a composite powder.

[0065] Disperse 1 g of nano-SiO2 in a beaker containing 20 mL of hexamethyldisilazane, place the beaker in a water bath, heat to 65°C, stir and react for 4 hours, filter, wash three times with anhydrous ethanol, and vacuum dry at 60°C for 13 hours to obtain modified nano-SiO2.

[0066] Mix 18g of perfluorohexanone with 0.1g of perfluoropolyether-based surfactant and continue stirring. Then add 0.5g of modified nano-SiO2 and 3g of ZIF-8 loaded with calcium fluoride in sequence. Shear at high speed. Add 1.5g of composite powder. Stir evenly and mix with 80g of heptafluoropropane to obtain heptafluoropropane fire extinguishing agent.

[0067] The present invention also carried out comparative examples and related tests.

[0068] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, ZIF-8 loaded with calcium fluoride was not prepared, and only calcium fluoride was used. The other compositions and preparation methods were the same as those in Example 1, and a heptafluoropropane fire extinguishing agent was prepared.

[0069] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the composite powder was not prepared in Comparative Example 2, and the other compositions and preparation methods were the same as those in Example 1, and a heptafluoropropane fire extinguishing agent was prepared.

[0070] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that perfluorohexanone is not added in Comparative Example 3, and the other compositions and preparation methods are the same as those in Example 1, and a heptafluoropropane fire extinguishing agent is prepared.

[0071] Performance testing The heptafluoropropane fire extinguishing agents prepared in Examples 1-7 and Comparative Examples 1-3 were used in fire extinguishing experiments, respectively, with n-heptane as the extinguishing target. n-heptane was injected into a combustion disk in a closed combustion chamber and ignited. After the flame height stabilized, the heptafluoropropane fire extinguishing agent was sprayed, and the time taken for the flame to be completely extinguished was recorded. Whether there was re-ignition within 5 minutes of extinguishing the fire was monitored, and the concentrations of HF and CO in the post-combustion gas were detected. The results are shown in Table 1 below.

[0072] Table 1

[0073] As can be seen from Table 1 above, compared with Example 1, after the heptafluoropropane fire extinguishing agent prepared in Comparative Example 1 extinguished the fire, the HF content in the gas was significantly increased, indicating that the calcium fluoride-loaded ZIF-8 can effectively adsorb harmful gases generated by combustion and reduce pollution; after the heptafluoropropane fire extinguishing agent prepared in Comparative Example 2 extinguished the fire, a re-ignition phenomenon occurred, and the fire extinguishing time was also longer. It can be seen that the fire extinguishing performance of the heptafluoropropane fire extinguishing agent prepared in Comparative Example 2 is significantly different from that of Example 1, indicating that tris (tribromophenoxy) triazine and nano-silica in the composite powder can effectively enhance the fire extinguishing ability of the heptafluoropropane fire extinguishing agent and inhibit re-ignition; compared with Example 1, the fire extinguishing ability of the heptafluoropropane fire extinguishing agent prepared in Comparative Example 3 decreased to a certain extent, indicating that the gas-liquid two-phase system synergistically formed by perfluorohexane and heptafluoropropane can promote the fire extinguishing agent to play a better role.

[0074] Compared with Example 6, the heptafluoropropane fire extinguishing agent prepared in Example 7 does not use zinc borate. It can be seen that its fire extinguishing time is longer, indicating that the addition of zinc borate can improve the flame retardant and oxygen isolation ability of the fire extinguishing agent, thereby enhancing the fire extinguishing ability of the fire extinguishing agent.

[0075] The above is a preferred embodiment of the present invention. Those skilled in the art may make several improvements and modifications without departing from the principles of the present invention. These improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a heptafluoropropane fire extinguishing agent, characterized in that: The following steps are involved: Step S1, adding calcium fluoride nanoparticles to anhydrous ethanol, and after completely dispersing, adding ZIF-8, ultrasonically treating, standing, filtering, and drying to obtain ZIF-8 loaded with calcium fluoride; Step S2, putting tris(tribromophenoxy)triazine into a grinder for grinding, then adding fumed nano-silica, and dry-mixing to obtain a composite powder; Step S3: perfluorohexanone and a perfluoropolyether-based surfactant are mixed, and the mixture is continuously stirred. Modified nano-SiO2 and calcium fluoride-loaded ZIF-8 are added in sequence, and sheared at high speed. Finally, the composite powder is added, mixed evenly, and then mixed with heptafluoropropane to obtain a heptafluoropropane fire extinguishing agent.

2. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 1, characterized in that: In step S1, the preparation of ZIF-8 includes the following steps: dissolving 2-methylimidazole in methanol and mixing uniformly to obtain solution A; dissolving zinc nitrate in methanol, slowly adding solution A, passing nitrogen gas, heating in a water bath for reaction, centrifuging, washing, and drying to obtain ZIF-8.

3. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 2, characterized in that: The heating reaction temperature is 55-65° C. and the time is 5-7 hours.

4. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 1, characterized in that: In the step S2, the particle size of tris(tribromophenoxy)triazine after pulverization is 3-5 μm; the mass ratio of tris(tribromophenoxy)triazine to fumed nano-silica is (9-12):

1.

5. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 1, characterized in that: In step S3, the preparation of modified nano-SiO2 includes the following steps: dispersing nano-SiO2 in hexamethyldisilazane, heating and stirring, filtering, washing, and drying to obtain modified nano-SiO2.

6. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 5, characterized in that: The heating and stirring is performed at a temperature of 55-65° C. and for a time of 4-6 hours.

7. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 5, characterized in that: The drying temperature is 60-70° C. and the drying time is 10-14 hours.

8. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 1, characterized in that: In step S3, the stirring speed is continuously 150-250 rpm.

9. The method for preparing a heptafluoropropane fire extinguishing agent according to claim 1, characterized in that: In the step S3, zinc borate is added before the modified nano-SiO2 and the ZIF-8 loaded with calcium fluoride are added in sequence, and ultrasonic dispersion is performed.

10. A heptafluoropropane fire extinguishing agent, characterized in that: The heptafluoropropane fire extinguishing agent is prepared by the preparation method of any one of claims 1 to 9, comprising the following components in parts by weight: 15-20 parts of perfluorohexanone, 0.05-0.1 parts of perfluoropolyether-based surfactant, 0.3-0.8 parts of modified nano-SiO2, 2-3 parts of ZIF-8 loaded with calcium fluoride, 0.5-1.5 parts of composite powder and 70-80 parts of heptafluoropropane.

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