Perfluoroketone microcapsule fire extinguishing agent based on complex coacervation method and preparation method thereof

Abstract

The application discloses a perfluorohexanone microcapsule fire extinguishing agent based on a complex coagulation method and a preparation method thereof. The fire extinguishing agent is prepared by taking perfluorohexanone as a core material, insoluble complexes formed by a complex coagulation reaction of gelatin and sodium hexametaphosphate at pH 4.0-5.0 as a wall material, and being double-crosslinked and solidified. The application obtains a stable perfluorohexanone emulsion by introducing an emulsifier Span 80 into an emulsified solution of gelatin and perfluorohexanone, and sequentially performs two crosslinking and solidification through glutaraldehyde and resorcinol and formaldehyde after the complex coagulation encapsulation, so that the coating rate, stability, mechanical strength and thermal response sensitivity of the microcapsule are significantly improved. The obtained microcapsule fire extinguishing agent shows excellent flame inhibition and thermal propagation blocking capacity in the simulation of electric meter box fire and lithium ion battery thermal runaway test, can effectively delay the thermal runaway starting time and reduce the peak temperature, and provides a microcapsule fire extinguishing agent which is efficient, stable, safe and has repeated fire extinguishing performance for lithium battery, special electric appliance cabinet, data center and other scenes which need continuous fireproofing / explosion suppression protection.

Description

Technical Field

[0001] This invention belongs to the field of novel fire extinguishing materials technology, and relates to a clean and efficient microencapsulated fire extinguishing agent, particularly a microencapsulated fire extinguishing agent based on perfluorohexanone as the core material and its preparation method. Background Technology

[0002] Perfluorohexanone, chemically known as perfluoro-2-methyl-3-pentanone, is a clear, colorless, and odorless liquid at room temperature. As a novel clean fire extinguishing agent, perfluorohexanone is widely considered an ideal alternative to traditional halon fire extinguishing agents due to its excellent fire extinguishing efficiency and outstanding environmental performance.

[0003] In terms of environmental performance, perfluorohexanone has an ozone depletion potential (ODP) of zero, meaning it does not damage the ozone layer at all; its global warming potential (GWP) is extremely low, at only 1; at the same time, it has a very short residence time in the atmosphere, with a lifespan of only 5 days, so its impact on global warming is negligible.

[0004] In terms of fire extinguishing performance, perfluorohexanone (PFH) is characterized by high extinguishing efficiency and low extinguishing concentration. In particular, PFH is non-conductive, making it ideal for extinguishing electrical fires, such as those in data centers, communication equipment rooms, power distribution rooms, and lithium-ion battery fires. It can extinguish fires while preventing secondary short-circuit damage to precision electronic equipment. In lithium-ion battery fires, PFH can rapidly reduce battery temperature, effectively inhibiting thermal runaway and its spread. Furthermore, PFH can also be used to extinguish fires involving flammable liquids and gases.

[0005] In terms of safety, perfluorohexanone is non-toxic and non-corrosive at normal usage concentrations, harmless to humans and non-irritating to the skin. Furthermore, due to its high volatility, it completely evaporates into a gas after extinguishing a fire, leaving no solid or liquid residue on the surface of objects. This means it will not contaminate the protected object, greatly simplifying post-disaster cleanup.

[0006] Despite its numerous advantages, perfluorohexanone (PFH) still faces some inherent technical challenges in practical applications. Firstly, its low boiling point, high vapor pressure at room temperature, and high volatility not only lead to extinguishing agent loss, reduced extinguishing effectiveness, and increased replenishment costs, but also necessitate special sealed storage and transportation conditions, thus limiting its application in resource-constrained or long-term storage scenarios. Secondly, its rapid evaporation rate results in a short effective residence time within the protected area after spraying, meaning that reignition may not be promptly suppressed due to the evaporation of the extinguishing agent, posing a risk of reignition. Furthermore, while PFH is harmless to humans at normal usage concentrations, studies have shown that at high concentrations or high temperatures, it decomposes to produce toxic hydrofluoric acid, posing a potential hazard to personnel and equipment. Therefore, measures are needed to control its release concentration or reduce hydrofluoric acid generation.

[0007] To address the aforementioned issues, existing technologies attempt to prepare perfluorohexanone into microcapsules. Microencapsulation technology utilizes natural or synthetic polymer materials as wall materials to encapsulate solid, liquid, or gaseous substances within tiny capsules. Through microencapsulation, the wall material effectively prevents perfluorohexanone from contacting the external environment, significantly reducing its volatilization rate and improving its storage stability. Microencapsulated perfluorohexanone is in solid powder form, facilitating handling, storage, and transportation without requiring special containers or conditions. By selecting appropriate wall materials and preparation processes, controlled release of perfluorohexanone can be achieved, extending the duration of fire extinguishing while avoiding high-concentration decomposition caused by its instantaneous large-scale release in a fire, thereby reducing the generation of hydrofluoric acid. Furthermore, microencapsulation can improve the compatibility of perfluorohexanone with other materials, facilitating its combined use with fire extinguishing agent carriers or other functional materials, expanding its application scenarios. Currently, the main technologies for preparing perfluorohexanone microcapsules include interfacial polymerization, in-situ polymerization, spray drying, and complex condensation.

[0008] Interfacial polymerization is a common method for preparing perfluorohexanone microcapsules. This method involves dispersing perfluorohexanone (PFH) as the core material in an oil phase containing oil-soluble wall material monomers such as diisocyanates and emulsifiers, emulsifying to form an oil phase solution. Then, an aqueous solution containing water-soluble wall material monomers such as polyamines and a catalyst is slowly added to the oil phase solution, and high-speed stirring forms a stable O / W emulsion. By heating, a polymerization reaction occurs at the interface between the two phases, forming a dense polymer wall material that encapsulates the core material. After centrifugation, washing, and drying, perfluorohexanone microcapsules are obtained. This method can produce microcapsules with small particle sizes and thin shells, but it requires precise control of reaction conditions to prevent excessive volatilization of perfluorohexanone during polymerization. It has high requirements for reaction conditions and requires the use of large amounts of organic solvents and emulsifiers, which may have some environmental impact, making the process relatively complex.

[0009] In-situ polymerization involves mixing perfluorohexanone with an emulsifier and stirring at high speed in an aqueous phase to form an emulsion. This disperses the perfluorohexanone as tiny droplets in a medium containing the wall material precursor. The precursor then polymerizes on the core material surface through heating, light exposure, or initiation with an initiator to form the wall material. Commonly used wall material precursors include urea-formaldehyde resin and melamine-formaldehyde resin. The advantages of in-situ polymerization are its simple process, low cost, ease of industrial production, and strong bonding between the wall material and the core material. However, the microcapsule wall materials prepared by this method may have a certain porosity, and the core material's encapsulation efficiency and storage stability need further improvement. Furthermore, raw materials such as formaldehyde may have some toxicity.

[0010] Spray drying involves dissolving perfluorohexanone and the encapsulation material in a solvent and then spray drying to form microcapsules. It has advantages such as high production efficiency and simple operation, but the efficiency may not be high, the selection of encapsulation materials is limited, the density is insufficient, the coverage rate is relatively low, and some core material may be lost due to volatilization during the drying process.

[0011] Complex coagulation utilizes two oppositely charged polymeric electrolytes as wall materials. Under appropriate conditions (adjusting pH, temperature, etc.), electrostatic interactions occur, forming a polyelectrolyte complex that encapsulates the core material. A gelatin-gum arabic system is commonly used as the wall material. This method offers mild conditions and good biocompatibility, but it has limitations such as low mechanical strength of the wall material, low encapsulation efficiency for hydrophobic core materials, and stringent requirements for process conditions such as pH and temperature.

[0012] For example, perfluorohexanone can be emulsified to form an O / W emulsion, gelatin can be added, the pH can be adjusted to make it positively charged, and then negatively charged gum arabic can be added. A complex coagulation reaction occurs on the surface of the core droplets to form a gel-like wall material, which can then be cured with a crosslinking agent to obtain perfluorohexanone microcapsules. However, the general limitations of the above complex coagulation method are particularly prominent in the perfluorohexanone system. The hydrophilic capsule wall has low encapsulation efficiency for the hydrophobic perfluorohexanone; the harsh process conditions make the encapsulation rate susceptible to the stability of the emulsion; and the wall material has low mechanical strength and poor thermal stability, making it difficult to meet the rapid response requirements in fire scenarios.

[0013] Despite the progress made in various perfluorohexanone microencapsulation technologies, challenges remain, including low encapsulation efficiency, complex and costly preparation processes, difficulty in precisely controlling release rates, numerous obstacles in scaling up from the laboratory to industrial applications, and a lack of unified performance evaluation standards. Perfluorohexanone, as an environmentally friendly and efficient fire extinguishing agent, has broad application prospects, but its volatility, inconvenient storage and transportation, and short residence time limit its application in a wider range of scenarios. Microencapsulation is an effective technical approach to address these issues. Developing perfluorohexanone microcapsules with high encapsulation efficiency, good storage stability, controllable release behavior, and suitability for large-scale production, along with their preparation method, is of great significance for promoting the development of clean fire extinguishing technologies and improving the fire prevention and control capabilities of critical facilities. Summary of the Invention

[0014] The purpose of this invention is to provide a perfluorohexanone microcapsule fire extinguishing agent based on the complex coagulation method and its preparation method. By introducing an emulsifier and adopting a secondary cross-linking curing process, the prepared fire extinguishing agent has good stability, high efficiency in fire extinguishing performance and reignition inhibition performance.

[0015] To achieve the above-mentioned objectives, this invention first provides a perfluorohexanone microcapsule fire extinguishing agent, which uses perfluorohexanone as the core material. The core material is prepared by forming a wall material by reacting natural polymer gelatin and sodium hexametaphosphate at a pH of 4.0 to 5.0 to encapsulate the core material. The resulting microcapsule fire extinguishing agent is then cured.

[0016] Specifically, this invention involves dissolving perfluorohexanone in a gelatin solution, then introducing the emulsifier Span 80 into the mixture of gelatin and perfluorohexanone to obtain a stable perfluorohexanone emulsion. This emulsion is then subjected to a coagulation reaction with sodium hexametaphosphate. The electrostatic interaction between the gelatin and sodium hexametaphosphate encapsulates the perfluorohexanone in microcapsules. The resulting microcapsule primary product undergoes dual cross-linking curing via glutaraldehyde and resorcinol and formaldehyde to ultimately form the microcapsule fire extinguishing agent product.

[0017] The microencapsulated fire extinguishing agent product prepared in this invention is designated as GEL / SHMP@C6F. 12 O.

[0018] Secondly, the present invention also provides a method for preparing the perfluorohexanone microcapsule fire extinguishing agent, specifically prepared according to the following method: 1) Disperse perfluorohexanone in a gelatin solution to form an emulsion; 2) Add emulsifier Span 80 to the emulsified solution, and emulsify to form a stable perfluorohexanone emulsion; 3) Adjust the pH of the perfluorohexanone emulsion to 4.0-5.0, add sodium hexametaphosphate solution dropwise, and carry out a coagulation reaction. Sodium hexametaphosphate and gelatin form an insoluble complex in an acidic environment through electrostatic attraction, which is then deposited on the surface of the core material as a wall material to prepare the microcapsule primary product. 4) Add glutaraldehyde solution to the microcapsule primary product for the first cross-linking and curing; 5) Add resorcinol solution and formaldehyde solution to the product after the first cross-linking and curing, and carry out the second cross-linking and curing to prepare the perfluorohexanone microcapsule fire extinguishing agent.

[0019] The addition of the emulsifier Span 80 can enhance the strength of gelatin as a shell material. Specifically, the volume of Span 80 added is 1-5% of the volume of the perfluorohexanone emulsion, preferably 2%.

[0020] In some embodiments of the present invention, the concentration of gelatin solution in the emulsion is preferably 3-5 wt.%, and the volume of perfluorohexanone added is 25-35% of the volume of the emulsion.

[0021] In some embodiments of the present invention, triethanolamine is preferably used as a pH adjuster to stabilize the pH of the perfluorohexanone emulsion within the required range.

[0022] In some embodiments of the present invention, the amount of sodium hexametaphosphate is 10 to 25 wt.% of the gelatin mass, preferably prepared as an aqueous solution with a concentration of 3 to 5 wt.%.

[0023] In some embodiments of the present invention, the complex condensation reaction is carried out under low temperature conditions, preferably at 8 to 10°C.

[0024] In some embodiments of the present invention, the amount of glutaraldehyde used for the first cross-linking and curing is 3.5 to 10 wt. of the initial mass of the microcapsule product.

[0025] Furthermore, the present invention preferably involves preparing glutaraldehyde into an aqueous solution with a concentration of 5-10 wt.%, adding it to the microcapsule primary product for the first cross-linking and curing, and stirring and curing at 25-35°C for 0.5-2 hours.

[0026] In some embodiments of the present invention, the amount of resorcinol used in the second cross-linking curing is 9 to 20 wt. of the mass of the first cross-linking curing product, and the amount of formaldehyde used is 15 to 20 wt. of the first cross-linking curing product.

[0027] Furthermore, the present invention preferably involves preparing resorcinol into an aqueous solution with a concentration of 10-15 wt.% and formaldehyde into an aqueous solution with a concentration of 25-30 wt.%, adding the first crosslinking curing product for a second crosslinking curing, and stirring and curing at 25-35°C for 0.5-2 hours.

[0028] Furthermore, the second cross-linking curing is more preferably achieved by first adding resorcinol solution, stirring at 25-35°C for 10-30 minutes, then adding formaldehyde solution, and stirring and curing at 25-35°C for 0.5-2 hours.

[0029] After filtering, washing, and drying the second crosslinking and curing product, the final perfluorohexanone microcapsule fire extinguishing agent product GEL / SHMP@C6F was prepared. 12 O.

[0030] The present invention also provides the application of the perfluorohexanone microcapsule fire extinguishing agent in equipment requiring continuous fire protection and / or explosion suppression protection.

[0031] Specifically, the equipment for continuous fire protection and / or explosion suppression may include, but is not limited to, lithium batteries, special electrical cabinets, data centers, communication equipment rooms, power distribution rooms, ship engine rooms, underground utility tunnels, etc.

[0032] This invention introduces the emulsifier Span 80 into a gelatin emulsion solution of perfluorohexanone to prepare a perfluorohexanone emulsion with stable shape and clear boundaries. This lays the foundation for subsequent pH adjustment and coagulation reaction. The heat-stable microcapsule primary product is obtained by coagulation reaction of sodium hexametaphosphate and gelatin under a specific acidic environment, and the microcapsule fire extinguishing agent is obtained by dual curing with glutaraldehyde and formaldehyde. The perfluorohexanone coating rate is over 8%, and the mass loss rate is only 2% after 30 days at room temperature, showing good coating effect and stability.

[0033] The perfluorohexanone microcapsule fire extinguishing agent of this invention effectively enhances the mechanical strength and thermal stability of gelatin-sodium hexametaphosphate complex cohesive wall material through a secondary cross-linking curing process, enabling it to meet the rapid response requirements in fire scenarios and be quickly activated to extinguish fires when exposed to open flames.

[0034] The perfluorohexanone microcapsule fire extinguishing agent of this invention exhibits excellent fire extinguishing performance: simulated localized fire tests in electrical meter boxes fully demonstrate the material's superior ability to block flame spread and heat propagation; in lithium-ion battery thermal runaway propagation suppression tests, it significantly delays the onset time of thermal runaway and substantially reduces the peak temperature. This perfluorohexanone microcapsule fire extinguishing agent is particularly suitable for scenarios prone to "sparking fires," providing a reliable solution that balances efficient fire extinguishing with equipment safety for modern fire prevention scenarios such as batteries, electronic devices, and confined spaces.

[0035] The preparation process of the perfluorohexanone microcapsule fire extinguishing agent of this invention is mild, and the fire extinguishing agent has the advantages of low toxicity and environmental friendliness. Attached Figure Description

[0036] Figure 1 This invention relates to the preparation of the microencapsulated fire extinguishing agent GEL / SHMP@C6F. 12 A picture of the actual product O.

[0037] Figure 2 It is GEL / SHMP@C6F 12 SEM image of cross section O.

[0038] Figure 3 It is GEL / SHMP@C6F 12 EDS element mapping analysis and distribution statistics of O.

[0039] Figure 4 It is GEL / SHMP@C6F 12 O 19 F NMR spectrum.

[0040] Figure 5 These are actual images of the microcapsule fire extinguishing agents prepared in Comparative Examples 1 and 2.

[0041] Figure 6It is GEL / SHMP@C6F 12 TG and DTG curves of O and GEL / SHMP and the results of stability tests.

[0042] Figure 7 It is GEL / SHMP@C6F 12 C6F in O 12 GC-MS quantitative test results of the coating rate of O.

[0043] Figure 8 It is a schematic structural diagram of the fire extinguishing test platform for microcapsule fire extinguishing agent.

[0044] Figure 9 It is GEL / SHMP@C6F 12 Infrared test fire extinguishing effect diagram of O.

[0045] Figure 10 It is GEL / SHMP@C6F[[ID=2​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Unless otherwise expressly stated, the production processes, experiments, tests or analysis methods involved in the embodiments of the present invention are all considered to be conventional methods known to those skilled in the art, and only need to be implemented in accordance with conventional conditions or relevant product instructions. The steps and names involved are also generally clear and unambiguous in the art.

[0053] The instruments, equipment, raw materials, reagents, or samples used in the embodiments are not subject to any special restrictions on their source. They are all conventional products that can be purchased through regular commercial channels or prepared by known methods, and their source does not have a substantial impact on the implementation results of the present invention.

[0054] Unless otherwise expressly defined, the scientific and technical terms used in this invention have the meanings commonly understood by one of ordinary skill in the art. In case of any conflict, the definitions in this specification shall prevail.

[0055] The terms “comprising,” “including,” “having,” etc., used in this invention should be understood as open-ended, meaning “including but not limited to.” The term “and / or” includes any and all combinations of one or more of the associated listed items. Quantitative terms such as “a,” “one,” etc., do not exclude multiples; “multiple” or “a variety” refers to quantities greater than or equal to two.

[0056] The terms "preferred", "better", and "exemplary" used in this invention are only used to describe specific solutions or effects and are not intended to be necessary limitations on the solution or restrictions on the scope of protection.

[0057] This invention relates to the description of numerical parameters (such as quantity, concentration, temperature, time, etc.), and it should be understood that reasonable deviations naturally exist due to measuring instruments, operational errors, statistical fluctuations, etc. The range of such deviations should be within limits acceptable to those skilled in the art based on common sense. Example

[0058] Example 1

[0059] 14 mL of perfluorohexanone was added to 32 mL of 5 wt% gelatin solution, emulsified for 5 min, and then 0.64 mL of Span 80 was added. The mixture was stirred and emulsified at 1300 rpm at 25 °C for 30 min to prepare a perfluorohexanone emulsion.

[0060] The pH of the perfluorohexanone emulsion was adjusted to 4.0–5.0 with triethanolamine, and 4.8 mL of 5 wt% sodium hexametaphosphate solution was added dropwise. The mixture was stirred and re-coagulated at 25 °C for 30 min, and then stirred in an ice bath at 8–10 °C for 1 h to prepare the microcapsule primary product.

[0061] Add 2 mL of 10 wt% glutaraldehyde solution to the microcapsule primary product, stir and crosslink at 30 °C for 1 h; then add 5 mL of 15 wt% resorcinol solution, stir at 35 °C for 15 min, add 10 mL of 28 wt% formaldehyde solution, stir and crosslink at 35 °C for 2 h.

[0062] The product was filtered, washed, and dried to prepare perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F. 12 O.

[0063] Figure 1 The actual image of the microcapsule fire extinguishing agent shows that the synthesized microcapsules are spherical solids with a uniform pale yellow or light golden yellow color.

[0064] Figure 2 GEL / SHMP@C6F was showcased. 12 The cross-sectional SEM image of O reveals numerous cavities of varying sizes within the material. These cavities are caused by the aggregation of the solution due to glutaraldehyde during the cross-linking and curing process of the capsule wall, resulting in a regular GEL / SHMP@C6F structure. 12 The O-microsphere structure is formed by extrusion, and then undergoes secondary curing with formaldehyde to reinforce the gelatin shell, enabling it to stably encapsulate perfluorohexanone and prevent its escape.

[0065] exist Figure 2 An untrimmed microsphere protrusion was captured in the image, and this part was targeted ( Figure 3 In (a)) an EDS element mapping analysis is performed, from Figure 3 (b) to (g) show that GEL / SHMP@C6F 12 The main elements C, N, O, F, Na, and P in O were uniformly dispersed in the sample. Further semi-quantitative analysis of the EDS scan results yielded the following elemental distribution: Figure 3 As shown in (h) and (i), the distribution results of each element are consistent with the actual situation of the material, thus proving that the scheme of coating perfluorohexanone with gelatin as the shell material using the complex coagulation method is feasible.

[0066] The charge properties of gelatin and SHMP are precisely complementary in an acidic environment with a pH of 4–5. At this time, gelatin carries a strong positive charge and SHMP carries a strong negative charge. The strong electrostatic attraction between the two drives efficient and rapid re-aggregation, forming a dense and uniform aggregated layer that tightly encapsulates the perfluorohexanone droplets. The good compatibility and synergistic effect of the two contribute to the high encapsulation rate of perfluorohexanone.

[0067] To further determine GEL / SHMP@C6F 12 Perfluorohexanone was successfully coated into O, and the material was analyzed using a Bruker AVANCEIII HD 400MHz laser from Germany.19 F NMR analysis was performed using dimethyl sulfoxide-d6 as the deuterated solvent. The results are as follows: Figure 4 As shown, a total of four characteristic peaks were generated. Among them, -75.02 ppm belongs to the linear terminal -CF3 and the branched -CF3; -81.80 ppm belongs to the linear terminal -CF3; -118.91 ppm belongs to the linear central -CF2; and -216.03 ppm belongs to the linear central -CF. The four characteristic peaks are completely matched with the chemical environments of the two types of -CF3, -CF2 and -CF in the perfluorohexanone molecule, respectively, which proves that perfluorohexanone core material does exist in the material. The test results further prove the successful preparation of microcapsules at the molecular level.

[0068] Example 2

[0069] 15 mL of perfluorohexanone was added to 30 mL of 5 wt% gelatin solution, emulsified for 5 min, and then 0.64 mL of Span 80 was added. The mixture was stirred and emulsified at 1000 rpm at 25 °C for 45 min to prepare a perfluorohexanone emulsion.

[0070] The pH of the perfluorohexanone emulsion was adjusted to 4.0–5.0 with triethanolamine, and 5 mL of 5 wt% sodium hexametaphosphate solution was added dropwise. The mixture was stirred and re-coagulated at 25 °C for 30 min, and then stirred in an ice bath at 8–10 °C for 1 h to prepare the microcapsule primary product.

[0071] Add 5 mL of 10 wt% glutaraldehyde solution to the microcapsule primary product, stir and crosslink at 30 °C for 1 h; then add 5 mL of 15 wt% resorcinol solution, stir at 35 °C for 15 min, add 10 mL of 25 wt% formaldehyde solution, stir and crosslink at 30 °C for 2 h.

[0072] The product was filtered, washed, and dried to prepare perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F. 12 O.

[0073] Example 3

[0074] 13 mL of perfluorohexanone was added to 30 mL of 6 wt% gelatin solution, emulsified for 10 min, and then 0.45 mL of Span 80 was added. The mixture was stirred and emulsified at 1500 rpm at 25 °C for 40 min to prepare a perfluorohexanone emulsion.

[0075] The pH of the perfluorohexanone emulsion was adjusted to 4.0–5.0 with triethanolamine, and 6 mL of 4 wt% sodium hexametaphosphate solution was added dropwise. The mixture was stirred and re-coagulated at 30 °C for 45 min, and then stirred in an ice bath at 8–10 °C for 1.5 h to prepare the microcapsule primary product.

[0076] Add 2 mL of 12 wt% glutaraldehyde solution to the microcapsule primary product, stir and crosslink at 30 °C for 1 h; then add 10 mL of 12 wt% resorcinol solution, stir at 30 °C for 20 min, add 8 mL of 30 wt% formaldehyde solution, stir and crosslink at 35 °C for 2.5 h.

[0077] The product was filtered, washed, and dried to prepare perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F. 12 O.

[0078] Comparative Example 1

[0079] 3M TM Novec TM FC-4430 is a nonionic polyfluorinated surfactant, primarily used as a wetting agent and leveling agent in the coatings, inks, and adhesives industries.

[0080] Given that FC-4430 and Span 80 have similar functions and complementary performance, this comparative example replaces Span 80 in Example 1 with an equal amount of FC-4430 to prepare a perfluorohexanone emulsion, and then prepares the perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F according to the method in Example 1. 12 O-FC4430.

[0081] The results are as follows Figure 5 As shown in (a), when FC-4430 is used as an emulsifier, the reaction product is liquid and no solid microcapsules are produced, so microcapsule materials cannot be successfully prepared.

[0082] Comparative Example 2

[0083] Without adding Span 80, 14 mL of perfluorohexanone was added to 32 mL of 5 wt% gelatin solution and emulsified for 5 min. Then, the mixture was stirred and emulsified at 1300 rpm at 25°C for 30 min to prepare a perfluorohexanone emulsion. The perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F was then prepared according to the method described in Example 1. 12 O-H2O.

[0084] The results are as follows Figure 5 As shown in (b), when no emulsifier is added, although white flocculent matter is generated, no spherical solids are produced, and microcapsule materials cannot be successfully prepared.

[0085] Comparative Example 3

[0086] Add 0.64 mL of Span 80 to 32 mL of 5 wt% gelatin solution, and emulsify by stirring at 1300 rpm at 25 °C for 30 min to prepare a gelatin emulsion.

[0087] The pH of the gelatin emulsion was adjusted to 4.0–5.0 with triethanolamine, and 4.8 mL of 5 wt% sodium hexametaphosphate solution was added dropwise. The mixture was stirred and re-coagulated at 25 °C for 30 min, and then stirred in an ice bath at 8–10 °C for 1 h to prepare the microcapsule primary product.

[0088] Add 2 mL of 10 wt% glutaraldehyde solution to the microcapsule primary product, stir and crosslink at 30 °C for 1 h; then add 5 mL of 15 wt% resorcinol solution, stir at 35 °C for 15 min, add 10 mL of 28 wt% formaldehyde solution, stir and crosslink at 35 °C for 2 h.

[0089] The product was filtered, washed, and dried to prepare microcapsules GEL / SHMP without perfluorohexanone core material.

[0090] Application Example 1

[0091] The perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F prepared in Example 1 was analyzed using a NETZSCH STA 2500 Regulus simultaneous thermal analyzer (Germany). 12 TG-DSC analysis was performed on O, with the core-free microcapsule GEL / SHMP prepared in Comparative Example 3 serving as a control.

[0092] The experiment was conducted in a nitrogen atmosphere, and the test material was heated from 30℃ to 800℃ at a heating rate of 10℃ / min. The test results are as follows: Figure 6 .

[0093] from Figure 6 (a) It can be seen that GEL / SHMP@C6F 12 The decomposition of O can be roughly divided into three stages: Stage I (230–300℃), Stage II (300–550℃), and Stage III (600–750℃). The low-temperature range of 30–150℃ corresponds to the evaporation of moisture. Stages II and III show a high degree of consistency with the pyrolysis curves of the microcapsule GEL / SHMP, indicating that they represent the pyrolysis process of the shell material. The weight loss in Stage II is mainly caused by the protein degradation and thermal decomposition of gelatin, while Stage III corresponds to the decomposition of phosphates in sodium hexametaphosphate.

[0094] It is worth noting that GEL / SHMP@C6F 12 The thermal behavior of O in stage I shows significant differences from that of GEL / SHMP, such as Figure 6 (b) shows a magnified view of GEL / SHMP@C6F 12 At this stage, a clearly identifiable thermal weight loss step emerged, with a mass loss of approximately 8.22%. Further combining... Figure 6The comprehensive analysis of the DTG curve in (c) further confirms the presence of GEL / SHMP@C6F. 12 O exhibited weight loss behavior in the temperature range of 230–300℃. By comparing the DTG curve of GEL / SHMP, it can be determined that the mass loss in this temperature range corresponds to the loss of the core material in the microcapsule material, thus confirming that the microcapsule fire extinguishing agent prepared by the complex coagulation method can achieve an encapsulation rate of more than 8%.

[0095] Meanwhile, to determine the stability of the microcapsule material, perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F was tested. 12 O was placed in an environment of 25°C for 30 consecutive days to monitor weight loss.

[0096] Figure 6 (d) shows the mass loss curve of the microcapsule material over 30 days. As can be seen from the figure, the leakage rate of the tested material is only 2% over 30 days. The mass decreases rapidly in the first 5 days because the evaporation of residual moisture in the material causes a rapid decrease in mass; the mass remains at 98% for the next 25 days, fluctuating with changes in ambient humidity.

[0097] Application Example 2

[0098] To gain a more scientific and reliable understanding of GEL / SHMP@C6F 12 The coating rate of O was determined, and the nature of the thermogravimetric process occurring in the TG curve at 230–300 °C was also determined. GC-MS was used to analyze the GEL / SHMP@C6F... 12 Quantitative analysis was performed on the core material in O.

[0099] The chromatography-mass spectrometry system used was a Thermo Fisher Trace1300-ISQ7000, with an injection port temperature of 250℃, an ion source temperature of 280℃, and an ion source transfer line temperature of 280℃. The scan range was 45–600 amu, the split ratio was set to splitless, and the column flow rate was 1.0 mL / min. The column temperature was started at 50℃, held for 1 min, and then increased to 250℃ at a rate of 10℃ / min and held for 3 min. The injection volume was 1 μL, and C6F was analyzed using the external standard method. 12 Quantitative analysis of O.

[0100] C6F was prepared at concentrations of 0.98%, 1.90%, and 4.90%, respectively. 12 GC-MS analysis was performed on standard solutions of O, and the peak areas of the target compounds in each standard solution were recorded. A standard curve was plotted with the standard solution concentration on the x-axis and the peak area on the y-axis, and the equation of the standard curve was calculated. y =61.2360 x -617436.9003, linear correlation coefficient R 2 =0.9992.

[0101] Weigh 0.10651g of the perfluorohexanone microcapsule fire extinguishing agent GEL / SHMP@C6F prepared in Example 1. 12 O was diluted to 0.5 mL with methanol, and the mixture was sonicated for 15 min to completely destroy the microcapsule wall material and release all the core material. After filtration through a filter membrane, samples were taken and tested according to the GC-MS conditions described above. The quantitative analysis results are as follows: Figure 7 As shown.

[0102] Figure 7 (b) shows that MS supports C6F 12 Five characteristic ions of the standard solution were monitored, with m / z values ​​of 51, 69, 82, 119, and 151. The same characteristic ions as those in the standard solution were clearly detected in the core material product released from the microcapsule extinguishing agent. This result directly confirms that the weight loss behavior in stage I of the TG curve mainly corresponds to the core material C6F. 12 The volatilization and release of O. Furthermore, using the characteristic ion 119 m / z as the quantitative ion, the chromatogram corresponding to (a) in the figure was obtained. The chromatographic peaks were calibrated and integrated to obtain the accurate peak areas. The C6F in the microcapsule fire extinguishing agent was calculated using the external standard method. 12 The O content was 8.7007%, and this test result is consistent with the TG test result.

[0103] Application Example 3

[0104] Building such Figure 8 The test platform shown was used to place a small sample of the microcapsule fire extinguishing agent onto a burning candle flame using tweezers. Simultaneously, a FOTEIC 288+ infrared thermal imager and a camera were used to observe and record the material's fire extinguishing performance, in order to study the microcapsule fire extinguishing agent GEL / SHMP@C6F. 12 O's fire extinguishing ability.

[0105] In practice, two equal masses of microcapsule fire extinguishing agent were weighed and named GEL / SHMP@C6F respectively. 12 O-1 and GEL / SHMP@C6F 12 O-2, under the same environment and within the same time period, conducted fire extinguishing tests on two samples, repeated 3 times. Figure 9 GEL / SHMP@C6F recorded by an infrared thermal imager 12 The fire extinguishing test diagram and the corresponding camera footage of the fire extinguishing process are shown below. Figure 10 As shown.

[0106] Figure 9 and Figure 10 It can be clearly observed in infrared thermal imaging and video images that GEL / SHMP@C6F 12O-1 and GEL / SHMP@C6F 12 O-2 achieved rapid and effective fire extinguishing in all three consecutive fire extinguishing tests, demonstrating that the microencapsulated fire extinguishing agent GEL / SHMP@C6F... 12 O has excellent fire extinguishing effect.

[0107] Furthermore, select Figure 9 The flame area in the diagram is used as the temperature acquisition area for the fire extinguishing test, and the corresponding fire extinguishing time curve is plotted as follows: Figure 11 As shown.

[0108] according to Figure 11 The test results show that the temperature in the flame area remained at around 500℃. The time from when the microcapsule was triggered to when the flame was completely extinguished was extremely short and the curve dropped sharply with no obvious delay. Furthermore, the temperature did not rise during the subsequent resting period, proving that no reignition occurred after the flame was extinguished.

[0109] The above test results show that the response and core material release of the microcapsule extinguishing agent are almost instantaneous. TG test results show that the microcapsule extinguishing agent undergoes violent decomposition in the temperature range of 230–300℃, which is far below the typical flame temperature of 500℃. This means that under flame conditions, the wall material of the microcapsule extinguishing agent can rapidly rupture, achieving C6F. 12 The instantaneous release of O allows for flame extinguishing within seconds, confirming the thermal response characteristics revealed by the TG analysis. Furthermore, this sustained protective effect directly demonstrates the effectiveness of GEL / SHMP@C6F. 12 O exhibits excellent stability and precise release capability.

[0110] Application Example 4

[0111] Using a simulated electricity meter model, a 2cm×2cm felt impregnated with 0.1mL of n-heptane was placed at the wiring terminal below the electricity meter model as an ignition source to simulate a fire inside the electricity meter box, and the actual fire suppression effect of the microcapsule fire extinguishing agent in a confined space was tested.

[0112] The test was divided into a blank group and an experimental group. No fire extinguishing patch was placed above the meter in the blank group, while a GEL / SHMP@C6F fire extinguishing patch was placed above the meter in the experimental group. 12 O Fire extinguishing patch.

[0113] Sample placement, thermocouple locations, and temperature profile are as follows: Figure 12 As shown in the diagram, the red squares on the meter represent fire extinguishing patches, and the yellow dots represent thermocouple points. The initial state of a fire in the meter box is simulated by igniting felt impregnated with n-heptane.

[0114] Test results show that placing GEL / SHMP@C6F 12The temperature at the wiring connection of the meter box in component O remained stable below 65℃ throughout the test, demonstrating excellent heat suppression; while the temperature of the blank control group rose rapidly, reaching a maximum of approximately 362℃, exhibiting violent combustion behavior. This proves that GEL / SHMP@C6F 12 The presence of O significantly inhibited the spread of flame and heat transfer, and the perfluorohexanone released after the microcapsules ruptured upon heating achieved a cooling effect.

[0115] Application Example 5

[0116] Settings such as Figure 13 The lithium-ion battery thermal runaway suppression test device shown defines the heating rod at position 2 as the lithium-ion battery that has experienced thermal runaway. The heating rod has a power of 150W and a maximum temperature of 500℃. The heating rod triggers thermal runaway in lithium-ion batteries at positions 1 and 3, and the temperature changes are recorded in real time using multiple thermocouples (red dots in the figure).

[0117] The test setup included a blank group and an experimental group. The blank group did not perform any protective treatment on the lithium-ion battery, while the experimental group used 4g of GEL / SHMP@C6F. 12 The oxide coating is applied to flame-retardant cloth and then wrapped around the surface of the lithium-ion battery. The test battery is an 18650 type lithium-ion battery, measuring 65×18.5mm, with a nominal capacity of 3000mAh, a standard voltage range of 2.5~4.2V, a charging current ≤3A, and a state of charge of 100%.

[0118] pass Figure 14 The temperature-time curves of the blank group and the experimental group at each test point during the test process show that the experimental group exhibits significant thermal runaway suppression efficacy at all key monitoring locations.

[0119] Figure 14 In the temperature changes of battery 1 in (a) and (b), the blank group experienced thermal runaway at 506s, while the experimental group experienced thermal runaway at 730s. Figure 14 In the temperature changes of battery 3 in (c) and (d), the blank group experienced a sudden temperature change and thermal runaway at 504 s, while the experimental group experienced thermal runaway at 712 s. The highest thermal runaway temperatures of the blank group batteries corresponding to batteries 1 and 3 were 719℃ and 614℃, respectively, while the highest thermal runaway temperatures of the experimental group batteries were 587℃ and 454.6℃, respectively. (GEL / SHMP@C6F) 12 The addition of O not only effectively delayed the onset of the sharp temperature rise by 224s and 208s respectively, but also reduced the peak temperature by 132℃ and 159.4℃ respectively, with a very significant suppression effect.

[0120] The figure also shows that although the temperature rise at positions T1 and T3', which are farther from the heating rod, is more gradual than that at positions T1' and T3, which are closer to the heating rod, the overall temperature level of the experimental group curves remains lower.

[0121] Comprehensive analysis shows that GEL / SHMP@C6F 12 O material demonstrates excellent thermal runaway propagation suppression capabilities by significantly delaying heat transfer, reducing peak temperature, weakening thermal feedback intensity, and blocking multi-stage thermal runaway chain reactions, proving its strong engineering application potential in improving the thermal safety level of lithium battery modules.

[0122] Application Example 6

[0123] To evaluate the microencapsulated fire extinguishing agent GEL / SHMP@C6F 12 The potential biotoxicity of O was tested using a mouse exposure model. Five- to six-week-old SPF-grade male BALB / c mice, weighing 24 ± 2 g, were randomly divided into a control group and an experimental group.

[0124] Using a self-built drug delivery system, the microencapsulated fire extinguishing agent GEL / SHMP@C6F was delivered. 12 The concentration of O volatilization is 2000 mg / m³. 3 The gas was delivered to the mouse chamber, and the experiment lasted for 7 days. During this period, the changes in the mice's activity level were observed and their weight was recorded. After the test, the corresponding organ tissues of the blank group and the experimental group were taken for HE staining analysis.

[0125] 1) General Behavioral Science and Weight Change

[0126] During the 7-day exposure experiment, all mice survived without death or near-death experiences. The experimental group mice exhibited normal activity throughout the exposure period, with no significant difference in spontaneous activity compared to the control group (P > 0.05). Feeding and drinking behaviors were normal, fur was smooth, and respiration was stable. No abnormal neurological behaviors such as agitation, convulsions, or lethargy were observed. Regarding weight changes, both groups of mice showed a steady increase in weight, with no statistically significant difference in weight between the control and experimental groups at any time point (P > 0.05).

[0127] 2) Histopathological analysis

[0128] HE staining results of mouse lung and kidney tissues are as follows Figure 15 As shown. Figure 15 In (a), the alveolar structures of mice in the blank group and the experimental group were intact and clear, the alveolar septa were not widened, there was no obvious inflammatory cell infiltration, no exudate was found in the alveolar cavity, and the bronchial epithelial structure was normal. Figure 15In (b), the glomeruli of mice in the blank group and the experimental group were intact, the renal tubular epithelial cells were neatly arranged, and no cell edema, vacuolar degeneration or necrosis was observed. No inflammatory cell infiltration or fibrotic changes were observed in the renal interstitium.

[0129] In summary, under the experimental conditions, GEL / SHMP@C6F 12 O did not induce detectable histopathological damage to the major respiratory and metabolic excretory organs of mice, nor did it cause any systemic adverse reactions. Mouse activity and weight were not significantly affected. GEL / SHMP@C6F 12 O exhibits high biosafety and good biocompatibility under exposure conditions, providing an important safety basis for its further application in the field of fire suppression in confined spaces.

[0130] The above embodiments of the present invention do not describe all details exhaustively, nor do they limit the present invention to the embodiments described above. Various changes, modifications, substitutions, and variations made by those skilled in the art to these embodiments without departing from the principles and spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A perfluorohexanone microcapsule fire extinguishing agent, comprising: using perfluorohexanone as the core material; preparing a microcapsule primary product by encapsulating the core material with a wall material formed by a complex coagulation reaction of gelatin and sodium hexametaphosphate at pH 4.0–5.0; and obtaining the microcapsule fire extinguishing agent GEL / SHMP@C6F after curing. 12 O, characterized by Perfluorohexanone was dissolved in a gelatin solution, and the emulsifier Span 80 was added to prepare a perfluorohexanone emulsion. This emulsion was then subjected to a coagulation reaction with sodium hexametaphosphate. The resulting microcapsule primary product was then cured by glutaraldehyde and by double cross-linking with resorcinol and formaldehyde to form a microcapsule fire extinguishing agent product.

2. The method for preparing the perfluorohexanone microcapsule fire extinguishing agent according to claim 1, characterized in that: Prepared according to the following method: 1) Disperse perfluorohexanone in a gelatin solution to form an emulsion solution; 2) Add emulsifier Span 80 to the emulsion solution to prepare perfluorohexanone emulsion; 3) Adjust the pH of the perfluorohexanone emulsion to 4.0-5.0, add sodium hexametaphosphate solution dropwise to carry out a coagulation reaction, and obtain the microcapsule primary product; 4) Add glutaraldehyde solution to the microcapsule primary product for the first cross-linking and curing; 5) Continue to add resorcinol solution and formaldehyde solution to the first cross-linking curing product, and carry out the second cross-linking curing to obtain microcapsule fire extinguishing agent.

3. The preparation method according to claim 2, characterized in that: The volume of Span 80 added is 1 to 5% of the volume of the perfluorohexanone emulsion.

4. The preparation method according to claim 2, characterized in that: The concentration of gelatin solution in the emulsion is 3-5 wt.%, and the volume of perfluorohexanone added is 25-35% of the volume of the emulsion.

5. The preparation method according to claim 2, characterized in that: The amount of sodium hexametaphosphate used is 10-25 wt.% of the gelatin mass, and it is prepared into an aqueous solution with a concentration of 3-5 wt.%.

6. The preparation method according to claim 2, characterized in that: The complex condensation reaction is carried out at 8–10 °C.

7. The preparation method according to claim 2, characterized in that: The amount of glutaraldehyde used in the first cross-linking and curing process is 3.5 to 10 wt. of the initial product mass of the microcapsule.

8. The preparation method according to claim 2, characterized in that: The amount of resorcinol used in the second cross-linking curing is 9-20 wt.% of the mass of the first cross-linking curing product, and the amount of formaldehyde used is 15-20 wt.% of the first cross-linking curing product.

9. The perfluorohexanone microcapsule fire extinguishing agent of claim 1 is used in continuous fire protection and / or explosion suppression protection equipment.

10. In the application according to claim 9, the continuous fire protection and / or explosion suppression protection device is a lithium battery, a special electrical cabinet, a data center, a communication equipment room, a power distribution room, a ship's engine room, or an underground utility tunnel.

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