Preparation method of active fire extinguishing microcapsule

Abstract

The invention discloses a preparation method of an active fire extinguishing microcapsule, and particularly relates to a fire extinguishing technology, the preparation method comprises the following steps: mixing a first monomer, a second monomer and a fluorinated acrylate monomer, adding an initiator, uniformly mixing, heating and polymerizing to obtain a shell material, dissolving the shell material in an organic solvent to obtain a solution, adding an emulsifier and perfluorohexanone at a low temperature, stirring to obtain an emulsion, and drying to obtain the active fire extinguishing microcapsule. Adding a surfactant aqueous solution into the emulsion, continuously stirring after low-temperature high-speed stirring to obtain a three-phase suspension, heating, standing, collecting and drying to obtain an active fire extinguishing microcapsule finished product. According to the preparation method of the active fire extinguishing microcapsule disclosed by the invention, the active fire extinguishing microcapsule has an efficient active fire extinguishing function, and when encountering high temperature, the microcapsule can be broken to quickly release an efficient fire extinguishing core material perfluorohexanone contained in the microcapsule, so that flame spreading is directly inhibited at the initial stage of a fire; the perfluorohexanone is used as an efficient fire extinguishing agent, the usage amount is small, and pollution to the environment is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of fire extinguishing, and in particular to a method for preparing active fire extinguishing microcapsules. Background Art

[0002] In the current fire protection field and fire scene solutions, the participation of firefighters or other professionals and related fire protection facilities is indispensable. However, the premise of implementing such fire solutions is that someone discovers and actively implements them.

[0003] As we all know, fires have a variety of causes. Generally speaking, in the early stages of a fire, temperatures are lower, the damage is less severe, and it's easier to extinguish. However, some fires are more hidden and difficult to detect in their early stages. By the time people discover them, the fire may have already grown to a considerable extent. Therefore, how to detect and extinguish a fire in its early stages is a crucial issue in the firefighting field.

[0004] Microcapsule fire extinguishing materials are a new material that has emerged in recent years. They typically consist of a shell and a core. The core, typically containing the fire extinguishing agent, is tightly encapsulated by an inorganic or organic shell. Under specific circumstances, such as high temperatures, the shell softens or melts, vaporizing and releasing the fire extinguishing agent in the core. This method extinguishes fires in their early stages by isolating oxygen and lowering the temperature.

[0005] Existing fire-extinguishing microcapsule preparation technologies primarily rely on physical injection and emulsion polymerization. While the physical method places high demands on manufacturing equipment, the emulsion polymerization method allows for flexible control of the microcapsule shell density, resulting in high production efficiency and widespread applicability, making it suitable for large-scale deployment. Microcapsules produced by different emulsion polymerization processes exhibit significant performance differences. Patent CN119185882A describes several fire-extinguishing microcapsule manufacturing methods and their shortcomings. For example, insufficient microcapsule shell strength can lead to rupture and loss of efficacy during physical mixing processes such as shearing and stirring during application. Using shell materials with alkaline functional groups can also impact the capsule's shelf life. Summary of the Invention

[0006] The main purpose of the present invention is to provide a method for preparing active fire-extinguishing microcapsules, which can effectively solve the problems involved in the above-mentioned background technology.

[0007] To achieve the above object, the technical solution adopted by the present invention is: A method for preparing active fire extinguishing microcapsules comprises the following steps: S1. Shell material preparation: Mix the first monomer, the second monomer and the fluoroacrylate monomer, add an initiator and mix thoroughly, heat to cause a polymerization reaction, and obtain a solid polymer after the reaction is completed, which is the shell material; S2. Preparation of core material emulsion: dissolving the shell material in an organic solvent to obtain a shell material solution, maintaining a low temperature environment, adding an emulsifier and the core material perfluorohexanone, and dispersing by stirring to form a stable emulsion; S3, microcapsule preparation: gradually add the pre-prepared S2 emulsion to the surfactant aqueous solution, maintain low temperature and high-speed stirring during the addition, and continue stirring after the addition is completed to obtain a three-phase suspension; S4. Collecting and drying microcapsules: slowly heating the obtained suspension to room temperature and then letting it stand to allow the microcapsules to settle. The microcapsules are collected and dried to obtain finished active fire extinguishing microcapsules.

[0008] Preferably, in S1, the first monomer is selected from at least one of methyl acrylate (MA) and methyl methacrylate (MMA), the second monomer is selected from at least one of butyl acrylate (BA) and butyl methacrylate (MBA); and the fluoroacrylate monomer is selected from at least one of 2-perfluorooctylethyl acrylate (TEAc-8) and 2-perfluorohexylethyl acrylate (TEAc-6).

[0009] Preferably, the initiator in S1 is azobisisobutyronitrile (AIBN), and the added amount accounts for 3% to 7% of the total mass of the reaction monomers; the heating temperature is 70-90° C., and the polymerization reaction time is 4 to 8 hours.

[0010] Preferably, the organic solvent in S2 is ethyl chloride, and the low temperature environment is 5-15°C; the emulsifier is selected from at least one of 2-perfluorooctylethyl acrylate, 2-perfluorohexylethyl acrylate, and 2-perfluorohexylethyl methacrylate, and the added amount is 5% to 15% of the core material weight.

[0011] Preferably, the mass ratio of the core material to the solid shell material in S2 is 0.8:1-1.2:1, the stirring speed is 500-1000 rpm, and the stirring time is 3-10 minutes; the stirring and dispersion is performed by mechanical stirring or ultrasonic dispersion.

[0012] Preferably, the surfactant in S3 is sodium lauryl sulfate, the low temperature environment is 5-15° C., the stirring speed is 1500-2500 rpm, and the continuous stirring time is 20 to 40 minutes; and the surfactant aqueous solution is a saturated solution.

[0013] Preferably, the drying temperature in S4 is 30-50° C., and the drying time is 4-8 hours; the drying treatment is performed by vacuum drying or forced air drying.

[0014] Preferably, the rate of slowly heating in S4 is 0.5-2°C / min.

[0015] Preferably, in S1, the mass ratio of the first monomer, the second monomer and the fluoroacrylate monomer is 1:1:1.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The active fire-extinguishing microcapsules of the present invention have a highly efficient active fire-extinguishing function. When exposed to high temperatures, the microcapsules will rupture and quickly release the highly efficient fire-extinguishing core material perfluorohexanone contained therein, directly suppressing the spread of flames in the early stages of a fire. Perfluorohexanone is a highly efficient fire extinguishing agent and is used in relatively small amounts, reducing pollution to the environment.

[0017] 2. The active fire extinguishing microcapsules of the present invention have a simple preparation process and are a green chemical preparation process. Ethyl chloride can be recovered by condensation, and there is no atomic waste in the whole process. The economy of the preparation process is suitable for large-scale production.

[0018] 3. The active fire extinguishing microcapsules of the present invention also ensure the long-term stability of the material. The physical isolation of the shell material from the fire extinguishing agent ensures the stability of the fire extinguishing agent. The absence of alkaline groups in the shell material ensures that the fire extinguishing medium will not become ineffective due to long-term storage or volatilization.

[0019] 4. The active fire-extinguishing microcapsules of the present invention have outstanding application flexibility and are suitable for a wide range of industrial applications, such as electronic equipment, automotive parts, and building materials. Overall, the active fire-extinguishing microcapsules of the present invention exhibit significant advantages in active fire extinguishing, environmental protection, mechanical property maintenance, and long-term flame retardant effects, and are an efficient, safe, and innovative flame-retardant material. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a preparation flow chart of the present invention; Figure 2 This is a physical picture of the fire extinguishing microcapsules produced in Example 1 of the present invention; Figure 3 For the present invention Figure 2 Microscopic morphology of fire-extinguishing microcapsules. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The process parameters for which specific conditions are not specified in the following examples are generally based on conventional conditions.

[0022] like Figure 1As shown, a method for preparing active fire extinguishing microcapsules specifically includes the following steps: S1. Shell material preparation: Mix the first monomer, the second monomer and the fluoroacrylate monomer, add an initiator and mix thoroughly, heat to cause a polymerization reaction, and obtain a solid polymer after the reaction is completed, which is the shell material; S2. Preparation of core material emulsion: dissolving the shell material in an organic solvent to obtain a shell material solution, maintaining a low temperature environment, adding an emulsifier and the core material perfluorohexanone, and dispersing by stirring to form a stable emulsion; S3, microcapsule preparation: gradually add the pre-prepared S2 emulsion to the surfactant aqueous solution, maintain low temperature and high-speed stirring during the addition, and continue stirring after the addition is completed to obtain a three-phase suspension; S4. Collecting and drying microcapsules: slowly heating the obtained suspension to room temperature and then letting it stand to allow the microcapsules to settle. The microcapsules are collected and dried to obtain finished active fire extinguishing microcapsules.

[0023] Specifically, in S1, the first monomer is selected from at least one of methyl acrylate (MA) and methyl methacrylate (MMA); the second monomer is selected from at least one of butyl acrylate (BA) and butyl methacrylate (MBA); the fluoroacrylate monomer is selected from at least one of 2-perfluorooctylethyl acrylate (TEAc-8) and 2-perfluorohexylethyl acrylate (TEAc-6); The initiator in S1 is azobisisobutyronitrile (AIBN), and the amount added is 3% to 7% of the total mass of the reaction monomers; the heating temperature is 70-90°C, and the polymerization reaction time is 4 to 8 hours; The organic solvent in S2 is ethyl chloride, and the low temperature environment is 5-15°C; the emulsifier is selected from at least one of 2-perfluorooctylethyl acrylate, 2-perfluorohexylethyl acrylate, and 2-perfluorohexylethyl methacrylate, and the amount added is 5% to 15% of the core material weight; The mass ratio of the core material to the solid shell material in S2 is 0.8:1-1.2:1, the stirring speed is 500-1000 rpm, and the stirring time is 3-10 minutes; the stirring and dispersion is performed by mechanical stirring or ultrasonic dispersion; The surfactant in S3 is sodium lauryl sulfate, the low temperature environment is 5-15°C, the stirring speed is 1500-2500 rpm, and the continuous stirring time is 20-40 minutes; the surfactant aqueous solution is a saturated solution; The drying temperature in S4 is 30-50°C, and the drying time is 4-8 hours; the drying treatment adopts vacuum drying or blast drying, and the rate of slowly heating in S4 is 0.5-2°C / min; In S1, the mass ratio of the first monomer, the second monomer and the fluoroacrylate monomer is 1:1:1.

[0024] During the specific production process, production parameters need to be adjusted according to environmental parameters such as temperature and humidity of the actual production environment, and products used in different scenarios also need to be manufactured by using compositions in different proportions. To facilitate understanding, the present invention is further disclosed and explained below in conjunction with specific parameters. For the convenience of expression, some materials are displayed using abbreviations.

[0025] Example 1: MA+BA+TEAc-8 system, its product is as follows Figure 2 As shown in the attached figure, the microcapsule powder is placed in an evaporating dish, and the powders agglomerate to form irregularly sized agglomerates. Further, through electron microscope observation, it can be seen that Figure 3 The fire extinguishing microcapsules shown in the figure are coated microcapsules, and the rest are uncoated shell material polymer fragments. S1: MA, BA, and TEAc-8 were mixed in a mass ratio of 1:1:1, with 10 g of MA added. 1.5 g of AIBN was then added. After mixing, ultrasonication was performed for 5 min to obtain a transparent and uniform solution. The solution was heated at 80°C. After polymerization, a solid was obtained, which was the shell material to be used.

[0026] S2: Take 30 g of the solid in S1, put it into a conical flask, and add 30 g of ethyl chloride. Stir at 10°C and 1500 rpm / min until the solid is completely dissolved in the ethyl chloride to obtain a shell material solution.

[0027] 30 g of perfluorohexanone was added to the shell material solution, and then 3 g of TEAc-8 was added and stirred at 10° C. and 800 rpm / min until a uniform and stable emulsion was obtained.

[0028] S3: The emulsion obtained in S2 was added dropwise to 200 ml of a saturated sodium dodecyl sulfate aqueous solution at 10° C., with stirring maintained at 2000 rpm at 10° C. During the addition, stirring was continued for 30 minutes after the addition was completed to obtain a three-phase suspension.

[0029] S4: slowly heating the suspension obtained in S3 at room temperature, and after it reaches room temperature, allowing the suspension to stand to allow the microcapsules to settle at the bottom. After collecting the microcapsules, drying them at 40°C for 6 hours to obtain the active fire extinguishing microcapsules, and drying them at 50°C to obtain the product.

[0030] Example 2: MMA+MBA+TEAc-8 system; S1: MMA, MBA, and TEAc-8 were mixed in a mass ratio of 1:1:1. The amount of MMA added was 10 g. Then 1.5 g of AIBN was added. After mixing, ultrasonication was performed for 5 min to obtain a transparent and uniform solution. The solution was heated at 80°C. After polymerization, a solid was obtained, which was the shell material to be used.

[0031] S2: Take 30 g of the solid in S1, put it into a conical flask, and add 30 g of ethyl chloride. Stir at 10°C and 1500 rpm / min until the solid is completely dissolved in the ethyl chloride to obtain a shell material solution.

[0032] 30 g of perfluorohexanone was added to the shell material solution, and then 3 g of TEAc-8 was added and stirred at 10° C. and 800 rpm / min until a uniform and stable emulsion was obtained.

[0033] S3: The emulsion obtained in S2 was added dropwise to 200 ml of a saturated sodium dodecyl sulfate aqueous solution at 10° C., with stirring maintained at 2000 rpm at 10° C. During the addition, stirring was continued for 30 minutes after the addition was completed to obtain a three-phase suspension.

[0034] S4: slowly heating the suspension obtained in S3 at room temperature, and after it reaches room temperature, allowing the suspension to stand to allow the microcapsules to settle at the bottom. After collecting the microcapsules, drying them at 40°C for 6 hours to obtain the active fire extinguishing microcapsules, and drying them at 50°C to obtain the product.

[0035] Example 3: MA+BA+TEAc-6 system; S1: MA, BA, and TEAc-6 were mixed in a mass ratio of 1:1:1, with 10 g of MA added. 1.5 g of AIBN was then added. After mixing, ultrasonication was performed for 5 min to obtain a transparent and uniform solution. The solution was heated at 80°C. After polymerization, a solid was obtained, which was the shell material to be used.

[0036] S2: Take 30 g of the solid in S1, put it into a conical flask, and add 30 g of ethyl chloride. Stir at 10°C and 1500 rpm / min until the solid is completely dissolved in the ethyl chloride to obtain a shell material solution.

[0037] 30 g of perfluorohexanone was added to the shell material solution in S2, and then 3 g of TEAc-8 was added and stirred at 10°C and 800 rpm / min until a uniform and stable emulsion was obtained.

[0038] S3: The emulsion obtained in S2 was added dropwise to 200 ml of a saturated sodium dodecyl sulfate aqueous solution at 10° C., with stirring maintained at 2000 rpm at 10° C. During the addition, stirring was continued for 30 minutes after the addition was completed to obtain a three-phase suspension.

[0039] S4: slowly heating the suspension obtained in S3 at room temperature, and after it reaches room temperature, allowing the suspension to stand to allow the microcapsules to settle at the bottom. After collecting the microcapsules, drying them at 40°C for 6 hours to obtain the active fire extinguishing microcapsules, and drying them at 50°C to obtain the product.

[0040] Example 4: MMA+BA+TEAc-8 system; S1: MMA, BA, and TEAc-8 were mixed in a mass ratio of 1:1:1. The amount of MMA added was 10 g. Then 1.5 g of AIBN was added. After mixing, ultrasonication was performed for 5 minutes to obtain a transparent and uniform solution. The solution was heated at 80°C. After polymerization, a solid was obtained, which was the shell material to be used.

[0041] S2: Take 30 g of the solid in S1, put it into a conical flask, and add 30 g of ethyl chloride. Stir at 10°C and 1500 rpm / min until the solid is completely dissolved in the ethyl chloride to obtain a shell material solution.

[0042] 30 g of perfluorohexanone was added to the shell material solution, and then 3 g of 2-perfluorohexylethyl methacrylate was added and stirred at 800 rpm / min at 10° C. until a uniform and stable emulsion was obtained.

[0043] S3: The emulsion obtained in S2 was added dropwise to 200 ml of a saturated sodium dodecyl sulfate aqueous solution at 10° C., with stirring maintained at 2000 rpm at 10° C. During the addition, stirring was continued for 30 minutes after the addition was completed to obtain a three-phase suspension.

[0044] S4: slowly heating the suspension obtained in S3 at room temperature, and after it reaches room temperature, allowing the suspension to stand to allow the microcapsules to settle at the bottom. After collecting the microcapsules, drying them at 40°C for 6 hours to obtain the active fire extinguishing microcapsules, and drying them at 50°C to obtain the product.

[0045] Example 5: MA+MBA+TEAc-8 system; Preparation of S1 shell material: MA, MBA and TEAc-8 were mixed in a mass ratio of 1:1:1, with 10 g of MA, 10 g of MBA and 10 g of TEAc-8 added, and 1.5 g of AIBN (5% of the total monomer mass). After ultrasonication for 5 min, the mixture was polymerized at 80°C for 6 h to obtain the shell material.

[0046] Preparation of S2 emulsion: 30 g of shell material was dissolved in 30 g of ethyl chloride, stirred at 1500 rpm at 10°C to dissolve, 30 g of perfluorohexanone and 3 g of TEAc-8 emulsifier were added, and stirred at 800 rpm for 5 minutes to form an emulsion.

[0047] S3-S5: Same as Example 1, finally microcapsules are obtained.

[0048] Example 6: MA+BA+TEAc-8 system (emulsifier TEAc-6); S1-S2: Same as Example 1, S3 emulsifier: 3 g of 2-perfluorohexylethyl acrylate (TEAc-6) was used, and the rest of the operations were the same as Example 1.

[0049] Example 7: MMA+MBA+TEAc-6 system; S1: MMA, MBA, and TEAc-6 were mixed in a ratio of 1:1:1, with 10 g of MMA and 1.5 g of initiator, and polymerization was performed at 80°C for 6 h. S2-S5: Same as Example 1, except that TEAc-83g was used as the emulsifier.

[0050] Example 8: MMA+BA+TEAc-6 system; S1: MMA, BA, and TEAc-6 were mixed at a ratio of 1:1:1, MMA 10 g, AIBN 1.5 g; S2-S5: Same as Example 1, except that the emulsifier was TEAc-83g.

[0051] Example 9: MA+MBA+TEAc-6 system; S1: 10g each of MA, MBA, TEAc-6, AIBN 1.5g; S3 emulsifier: 3 g of 2-perfluorohexylethyl methacrylate was used, and the remaining steps were the same as those in Example 1.

[0052] Example 10: MMA+MBA+TEAc-8 system (emulsifier 2-perfluorohexylethyl acrylate); S1-S2: Same as Example 2, except that S3 emulsifier was replaced with 3 g of 2-perfluorohexylethyl acrylate, and the stirring conditions remained unchanged.

[0053] Example 11: MA+BA+TEAc-8 system (emulsifier compounding); S3 emulsifier: 1.5 g each of TEAc-8 and 2-perfluorohexylethyl methacrylate (total mass 3 g, accounting for 10% of the core material) were used. The remaining steps were the same as in Example 1.

[0054] Example 12: MMA+BA+TEAc-6 system (emulsifier compounding); S1: 10g each of MMA, BA and TEAc-6; S3 emulsifier: TEAc-6 and 2-perfluorohexylethyl acrylate were mixed in a ratio of 1:1, with a total amount of 3 g. The remaining operations were the same as in Example 1.

[0055] The fire extinguishing effects of the products prepared based on the combinations of the above embodiments were tested. The test process was as follows: the fire extinguishing sheet was cut into pieces of 5cm*5cm*0.5cm and placed in a 10L box (with an opening on the top) containing burning gasoline. The time it took for the gasoline flame to extinguish was recorded. The results are shown in Table 1. Table 1: Fire extinguishing schedule for different combinations Furthermore, based on the above fire extinguishing time, the optimal ratio was found in different systems. The analysis showed that the best product based on the MA+BA system was Example 11, the best product based on the MA+MBA system was Example 5, the best product based on the MMA+BA system was Example 12, and the best product based on the MMA+MBA system was Example 2 or 10; The finished product produced in the above embodiment was further tested for glass transition temperature, thermal decomposition starting temperature and hydrophobicity. The results are shown in Table 2. Table 2: Characteristics of the effects of different monomer combinations on shell material performance According to the above extinguishing time and characteristic table, compared with Example 1, in Example 5, after the second monomer was replaced from BA to MBA, the hydrophobicity of the shell material was improved but the flexibility was slightly reduced, and the extinguishing time was maintained at 28 seconds. In Example 9, due to the simultaneous use of TEAc-6 fluorinated monomer and 2-perfluorohexylethyl methacrylate emulsifier, the difference in carbon chain length between the two resulted in a slightly slower release rate of the core material, and the extinguishing time was consistent with Examples 3 and 4 at 30 seconds. Furthermore, Example 11 uses a compound emulsifier to reduce surface tension, resulting in more uniform release of the core material and a shortened fire extinguishing time of 25 seconds, which is currently the best data. In Example 12, the increased amount of emulsifier improved the matching degree between the fluorinated monomer and the emulsifier carbon chain. However, the synergistic effect of the emulsifier used was relatively weak compared to the combination of TEAc-8 (C8 fluoroacrylate) and 2-perfluorohexylethyl methacrylate (C6 fluoromethacrylate) used in Example 11. Due to the high glass transition temperature of the C6 chain of TEAc-6 and the MMA system, the rupture threshold increased and the fire extinguishing time was extended to 27 seconds, but it was still higher than that of Example 8 using only a single emulsifier. Furthermore, the performance of the finished products of each embodiment was further analyzed. For the MMA system, namely Examples 2, 7, 10 and 12, the fire extinguishing time was concentrated in 26-27 seconds, which was 2-3 seconds faster than the MA system on average. This confirms that due to the steric hindrance effect of the methyl group, the methacrylate monomer has a higher glass transition temperature of the shell material and is more likely to rupture and release the core material faster when heated, making it suitable for high-temperature emergency fire extinguishing scenarios.

[0056] The MA system, namely Examples 1, 3, 5, 6, and 9, has a slightly longer fire extinguishing time, but has the advantage of flexibility. The materials used make the shell material have a low glass transition temperature, which can maintain the shell layer's elasticity in low-temperature environments, avoiding premature leakage of the core material due to brittle fracture. The shell material produced by the combination method used in Example 1 has an elongation at break of 210% at -10°C, while the MMA system only has an elongation of 150%, making it more suitable for fire protection of cold chain storage or low-temperature equipment. For the combination of two different fluoroacrylate monomers, the TEAc-8 system, i.e., Examples 1, 2, 5, 10, and 11, generally exhibited better fire extinguishing time than the TEAc-6 system, i.e., Examples 3, 6, 7, 8, 9, and 12, by an average of 2 seconds. This is because the fluorocarbon chains in the TEAc-8 system are longer, resulting in lower surface energy for the shell material and a lower thermal rupture threshold.

[0057] In the use of emulsifiers, the compound emulsifiers used in Examples 11 and 12 shorten the fire extinguishing time by 1 to 3 seconds compared with the single emulsifier system. Among them, the compound system of Example 11 reduces the microcapsule particle size distribution coefficient to 0.12 through the "fluorocarbon chain length complementarity" mechanism, and improves the core material release uniformity by 17%.

[0058] Emulsifiers containing methacrylate structures (such as 2-perfluorohexylethyl methacrylate) are more compatible with the polymer chain segments of the shell material, forming a denser interface layer and improving the encapsulation rate; The compounded emulsifier reduces the surface tension through synergistic effect (for example, the surface tension of TEAc-8 and 2-perfluorohexylethyl methacrylate is reduced from 28mN / m to 22mN / m), promotes uniform dispersion of droplets, and reduces particle size distribution. The specific impact characteristic data are shown in Table 3; Table 3: Characteristics of the effect of emulsifier type on microcapsule performance Based on the UL94 standard, a vertical combustion test was conducted on products using a combination of two different fluoroacrylate monomers. The microcapsules using TEAc-8 as the fluoromonomer extinguished the flame within 10 seconds, while the TEAc-6 system required 12 seconds. This is because TEAc-8 contains a longer fluorocarbon chain (C8) and a lower shell surface energy (14mN / m vs. 18mN / m for TEAc-6). It is more likely to rupture when heated to release perfluorohexanone, demonstrating better fire extinguishing efficiency. It is suitable for fire extinguishing scenarios that require a quick response. However, for scenarios where a continuous high temperature environment exists, the TEAc-6 system is relatively more stable.

[0059] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing active fire extinguishing microcapsules, characterized in that: The following steps are involved: S1. Shell material preparation: Mix the first monomer, the second monomer and the fluoroacrylate monomer, add an initiator and mix thoroughly, heat to cause a polymerization reaction, and obtain a solid polymer after the reaction is completed, which is the shell material; S2. Preparation of core material emulsion: dissolving the shell material in an organic solvent to obtain a shell material solution, maintaining a low temperature environment, adding an emulsifier and the core material perfluorohexanone, and dispersing by stirring to form a stable emulsion; S3, microcapsule preparation: gradually add the pre-prepared S2 emulsion to the surfactant aqueous solution, maintain low temperature and high-speed stirring during the addition, and continue stirring after the addition is completed to obtain a three-phase suspension; S4. Collecting and drying microcapsules: slowly heating the obtained suspension to room temperature and then letting it stand to allow the microcapsules to settle. The microcapsules are collected and dried to obtain finished active fire extinguishing microcapsules.

2. The method for preparing an active fire extinguishing microcapsule according to claim 1, characterized in that: In S1, the first monomer is selected from at least one of methyl acrylate (MA) and methyl methacrylate (MMA), the second monomer is selected from at least one of butyl acrylate (BA) and butyl methacrylate (MBA); the fluoroacrylate monomer is selected from at least one of 2-perfluorooctylethyl acrylate (TEAc-8) and 2-perfluorohexylethyl acrylate (TEAc-6).

3. The method for preparing active fire extinguishing microcapsules according to claim 1, characterized in that: The initiator in S1 is azobisisobutyronitrile (AIBN), and the added amount accounts for 3% to 7% of the total mass of the reaction monomers; the heating temperature is 70-90° C., and the polymerization reaction time is 4 to 8 hours.

4. The method for preparing active fire extinguishing microcapsules according to claim 1, characterized in that: The organic solvent in S2 is ethyl chloride, and the low temperature environment is 5-15°C; the emulsifier is selected from at least one of 2-perfluorooctylethyl acrylate, 2-perfluorohexylethyl acrylate, and 2-perfluorohexylethyl methacrylate, and the added amount is 5% to 15% of the core material weight.

5. The method for preparing active fire extinguishing microcapsules according to claim 1, characterized in that: The mass ratio of the core material to the solid shell material in S2 is 0.8:1-1.2:1, the stirring speed is 500-1000 rpm, and the stirring time is 3-10 minutes; the stirring and dispersion is performed by mechanical stirring or ultrasonic dispersion.

6. The method for preparing active fire extinguishing microcapsules according to claim 1, characterized in that: The surfactant in S3 is sodium lauryl sulfate, the low temperature environment is 5-15° C., the stirring speed is 1500-2500 rpm, and the continuous stirring time is 20-40 minutes; the surfactant aqueous solution is a saturated solution.

7. The method for preparing active fire extinguishing microcapsules according to claim 1, characterized in that: The drying temperature in S4 is 30-50° C., and the drying time is 4-8 hours; the drying treatment adopts vacuum drying or forced air drying.

8. The method for preparing active fire extinguishing microcapsules according to claim 1, characterized in that: The rate of slowly heating in S4 is 0.5-2°C / min.

9. The method for preparing active fire extinguishing microcapsules according to claim 1, characterized in that: In S1, the mass ratio of the first monomer, the second monomer and the fluoroacrylate monomer is 1:1:1.

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