Fire extinguishing microcapsule, and preparation method and application thereof

Abstract

The application discloses a fire extinguishing microcapsule and a preparation method and application thereof, and belongs to the technical field of fire extinguishing agents. The perfluorine fire extinguishing microcapsule comprises a core material, a wall material and an additive; the wall material is coated on at least part of the surface of the core material; the core material comprises a perfluorinated compound; the wall material comprises a hybrid amino resin; and the hybrid amino resin is obtained by modifying an amino resin with an aqueous isocyanate. The hybrid amino resin obtained by modifying the amino resin with the aqueous isocyanate is used as the wall material, the synergistic effect of the wall material component breaks through the limitation that a single wall material cannot be both strengthened and toughened at the same time, simultaneously solves the compatibility problem of a multi-layer coating system, and realizes the synchronous improvement of the thermal stability and structural integrity of the microcapsule. The microcapsule has good thermal stability, can release the core material when the temperature exceeds a critical value, and thus has good fire extinguishing effect.

Description

Technical Field

[0001] This invention belongs to the field of fire extinguishing agent technology, and particularly relates to a fire extinguishing microcapsule, its preparation method and application. Background Technology

[0002] Perfluorinated compounds (such as perfluorohexanone) have attracted widespread attention as a new type of environmentally friendly fire extinguishing agent due to their advantages such as high fire extinguishing efficiency, short atmospheric residence time, and no environmental damage. They are considered an ideal replacement for traditional fire extinguishing agents such as halon and Freon. Their fire extinguishing mechanism is mainly achieved through the dual effects of heat absorption and cooling, and inhibition of the combustion reaction chain, making them particularly suitable for fire protection in special locations such as electrical equipment, precision instruments, and data centers.

[0003] However, perfluorinated compounds have poor thermal stability. For example, even though perfluorohexanone is liquid at room temperature, its boiling point is only 49°C, making it highly volatile and difficult to use and store directly. Microencapsulating perfluorohexanone can effectively suppress its volatilization, enhance its storage stability, and release it when the temperature exceeds a certain critical value, thereby achieving a fire extinguishing effect.

[0004] The wall material of microcapsules directly determines their application effect. Currently, the wall materials used to coat perfluorohexanone in the preparation of fire extinguishing microcapsules are mainly polymeric materials, which can be broadly divided into natural polymeric materials (such as gelatin, gum arabic, chitosan, etc.) and synthetic polymeric materials (such as polyurethane, phenolic resin, acrylic resin, etc.). Existing technologies disclose fire extinguishing microcapsules using gelatin and gum arabic as wall materials, and chitosan and sodium alginate as wall materials. However, the aforementioned fire extinguishing microcapsules using natural polymers as wall materials suffer from problems such as low mechanical strength, poor thermal stability, and difficulty in continuous production. Other technologies disclose the preparation of fire extinguishing microcapsules through the reaction of isocyanates and amino-containing compounds (polyethylene polyamines), and the preparation of fire extinguishing microcapsules through in-situ low-temperature polymerization using melamine-formaldehyde resin as the wall material. Although microcapsules using the above-mentioned polymeric materials as wall materials can effectively improve thermal stability, single polymeric materials generally face the common problem of difficulty in simultaneously strengthening and toughening. In addition, some studies have proposed to prepare fire extinguishing microcapsules through multi-layer wall / wall material systems to solve the problems faced by single wall / wall materials. However, the multiple coating process will significantly increase the production cost and there is a problem of poor compatibility between different wall materials. Summary of the Invention

[0005] In order to overcome at least one of the problems existing in the prior art, one of the objectives of the present invention is to provide a perfluorinated fire extinguishing microcapsule that, through the synergistic effect of the wall material components, breaks through the limitation that single wall material reinforcement and toughening cannot be achieved simultaneously, and at the same time solves the compatibility problem of multilayer coating system, thereby achieving a simultaneous improvement in the thermal stability and structural integrity of the microcapsule.

[0006] The second objective of this invention is to provide a method for preparing the above-mentioned perfluorinated fire extinguishing microcapsules.

[0007] The third objective of this invention is to provide an application of the above-mentioned perfluorinated fire extinguishing microcapsules.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A first aspect of the present invention provides a perfluorinated fire extinguishing microcapsule comprising a core material, a wall material, and an additive; the wall material covers at least a portion of the surface of the core material; the additive is disposed at least at the interface between the core material and the wall material; the core material comprises a perfluorinated compound; the wall material comprises a hybrid amino resin; the hybrid amino resin is obtained by modifying an amino resin with an aqueous isocyanate.

[0009] In some embodiments of the present invention, the additive may also be disposed inside the core material, inside the wall material, or other locations.

[0010] In some embodiments of the present invention, the aqueous isocyanate is covalently linked to the amino resin.

[0011] In some embodiments of the present invention, the amino resin includes at least one of melamine-formaldehyde-urea (MUF) resin, melamine-formaldehyde (MF) resin, or urea-formaldehyde (UF) resin; in some specific embodiments of the present invention, the amino resin is selected from melamine-formaldehyde-urea (MUF) resin.

[0012] Amino resins are a class of nitrogen-rich compounds containing amino nitrogen or its derivatives. They are thermosetting resins obtained by polycondensation of amino monomers and aldehyde compounds (such as formaldehyde). Currently, amino resins include MUF resins, MF resins, and UF resins. Among them, MF resins have high rigidity but are brittle and easily broken; UF resins have linear molecular chains, low crosslinking degree, and poor thermal stability; in comparison, MUF resins have superior performance and can achieve better thermal stability when used in this invention.

[0013] In some embodiments of the present invention, the melamine content in the melamine-formaldehyde-urea resin is 0.1~20wt%; in some specific embodiments of the present invention, the melamine content in the melamine-formaldehyde-urea resin is 0.5~10wt%; in some more specific embodiments of the present invention, the melamine content in the melamine-formaldehyde-urea resin is 1~5wt%.

[0014] In some embodiments of the present invention, the NCO content of the aqueous isocyanate is 20-30 wt%; in some specific embodiments of the present invention, the NCO content of the aqueous isocyanate is 22-28 wt%; and in some more specific embodiments of the present invention, the NCO content of the aqueous isocyanate is 24-26 wt%.

[0015] The NCO content of waterborne isocyanates refers to the content of the active groups -N=C=O contained in the waterborne isocyanate.

[0016] In some embodiments of the present invention, the amount of the aqueous isocyanate is 0.4 to 5 wt% of the mass of the amino resin; in some specific embodiments of the present invention, the amount of the aqueous isocyanate is 0.8 to 4 wt% of the mass of the amino resin; in some more specific embodiments of the present invention, the amount of the aqueous isocyanate is 1 to 3 wt% of the mass of the amino resin.

[0017] Optimizing the amount of aqueous isocyanate can help improve the thermal stability of microcapsules.

[0018] In some embodiments of the present invention, the perfluorinated compound includes C3-C8 perfluoroketones, C3-C8 perfluoroalkanes, or combinations thereof; in some specific embodiments of the present invention, the perfluorinated compound is selected from C3-C8 perfluoroketones.

[0019] In some embodiments of the present invention, the perfluorinated compound includes at least one selected from perfluorohexanone, perfluoroacetone, perfluorobutanone, perfluoropentanone, perfluoropropane, perfluorobutane, perfluoropentane, perfluorohexane, perfluoroheptane, or perfluorooctane; in some specific embodiments of the present invention, the perfluorinated compound includes at least one selected from perfluorohexanone, perfluoroacetone, perfluorobutanone, or perfluoropentanone; in some more specific embodiments of the present invention, the perfluorinated compound is selected from perfluorohexanone.

[0020] In some embodiments of the present invention, the particle size range of the perfluorinated fire extinguishing microcapsules is 100~600μm; in some specific embodiments of the present invention, the particle size range of the perfluorinated fire extinguishing microcapsules is 200~500μm.

[0021] In some embodiments of the present invention, the mass ratio of the core material to the wall material is 1:(0.8~3); in some specific embodiments of the present invention, the mass ratio of the core material to the wall material is 1:(1~2.5); in some more specific embodiments of the present invention, the mass ratio of the core material to the wall material is 1:(1.2~2).

[0022] In some embodiments of the present invention, the mass ratio of the core material to the additive is 1:(0.01~0.2); in some specific embodiments of the present invention, the mass ratio of the core material to the additive is 1:(0.03~0.15); in some more specific embodiments of the present invention, the mass ratio of the core material to the additive is 1:(0.05~0.1).

[0023] In some embodiments of the present invention, the adjuvant includes a surfactant.

[0024] In some embodiments of the present invention, the surfactant is selected from nonionic surfactants and anionic surfactants or combinations thereof.

[0025] In some embodiments of the present invention, the hydrophilic group of the nonionic surfactant includes at least one of a polyoxyethylene chain and a polyol hydroxyl group; the hydrophilic group of the anionic surfactant includes at least one of a sulfonic acid group, a sulfate ester group, or a carboxyl group.

[0026] In some embodiments of the present invention, the surfactant includes at least one of nonylphenol polyoxyethylene ether, octylphenol polyoxyethylene ether, polyoxyethylene stearate, polyoxyethylene oleate, poloxamer 188, poloxamer 407, polyethylene glycol, polyglycerol-3 stearate, polyglycerol-6 oleate, glyceryl monostearate, glyceryl monooleate, pentaerythritol monostearate, pentaerythritol dioleate, sodium lauryl sulfate, sodium dodecylbenzene sulfonate, ethylene-maleic anhydride, polyethylene-maleic anhydride, or sodium polystyrene sulfonate; in some specific embodiments of the present invention, the surfactant includes at least one of nonylphenol polyoxyethylene ether, sodium lauryl sulfate, or ethylene-maleic anhydride.

[0027] In some embodiments of the present invention, the additive further includes polyethylene glycol; in some embodiments of the present invention, the polyethylene glycol in the additive is 5-15% by mass; for example, it can be any value of 5%, 8%, 10%, 12% or 15% or a range between any two.

[0028] A second aspect of the present invention provides a method for preparing perfluorinated fire extinguishing microcapsules, comprising the following steps: mixing an amino monomer, an aldehyde compound, an aqueous isocyanate, and water to react and obtain a hybrid amino resin prepolymer; mixing a perfluorinated compound, an additive, and water to form a solution containing a core material; mixing the hybrid amino resin prepolymer with the solution containing the core material to perform a microencapsulation reaction; and drying to obtain the perfluorinated fire extinguishing microcapsules as described in the first aspect of the present invention.

[0029] A one-step in-situ polymerization method encapsulates hybrid amino resins onto the surface of perfluorinated compounds, offering advantages in both performance and cost. Amino monomers and aldehydes can form amino resins through a condensation reaction. When mixed with aqueous isocyanate, the resulting hybrid amino resin prepolymer is in the prepolymer condensation stage, containing numerous unreacted hydroxymethyl and active amino groups on its molecular chains. The -NCO groups of the isocyanate can chemically crosslink with these active sites, allowing isocyanate molecules to directly embed into the three-dimensional network structure of the prepolymer, forming covalently linked amino resin prepolymer-isocyanate composite molecular chains. The prepolymer containing these composite molecular chains is then mixed with a solution containing a core material for microencapsulation. The hybrid amino resin prepolymer reacts to form a hybrid amino resin serving as the wall material, achieving a one-step encapsulation process that avoids the high costs associated with multiple encapsulation methods and possesses potential for large-scale production. Furthermore, the resulting perfluorinated fire extinguishing microcapsules exhibit excellent thermal stability.

[0030] In some embodiments of the present invention, the amino-containing monomer includes melamine, urea, or a combination thereof; in some specific embodiments of the present invention, the amino-containing monomer includes melamine and urea; in some more specific embodiments of the present invention, the mass ratio of melamine to urea in the amino-containing monomer is 1:(2~20); for example, it can be any value of 1:2, 1:5, 1:10, 1:15, or 1:20, or a range between any two.

[0031] In some embodiments of the present invention, the aldehyde compound includes at least one of formaldehyde, acetaldehyde, or butyraldehyde; in some specific embodiments of the present invention, the aldehyde compound is selected from formaldehyde.

[0032] In some embodiments of the present invention, the mass ratio of the amino-containing monomer to the aldehyde compound is 1:(2~5); for example, it can be any value of 1:2, 1:3, 1:4 or 1:5 or any range between two.

[0033] In some embodiments of the present invention, in the reaction of the amino-containing monomer, aldehyde compound, aqueous isocyanate and water, the mass ratio of the amino-containing monomer to water is 1:(0.5~3); for example, it can be any value or a range between 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5 or 1:3.

[0034] In some embodiments of the present invention, an amino monomer, an aldehyde compound, and water are first mixed and reacted, and then an aqueous isocyanate is added to react again to obtain a hybrid amino resin prepolymer. In some specific embodiments of the present invention, an amino monomer, an aldehyde compound, and water are first mixed, the pH value is adjusted to 8.5-9.5, heated to 60-80°C and reacted for 0.5-2 hours, cooled to 30-50°C, and then an aqueous isocyanate is added and reacted for 0.3-1 hours to obtain a hybrid amino resin prepolymer.

[0035] In some embodiments of the present invention, the pH of the microencapsulation reaction is 2.5 to 3.5; in some specific embodiments of the present invention, the pH of the microencapsulation reaction is 2.8 to 3.25; and in some more specific embodiments of the present invention, the pH of the microencapsulation reaction is 2.9 to 3.2.

[0036] In some embodiments of the present invention, the temperature of the microencapsulation reaction is 35~80°C; in some specific embodiments of the present invention, the temperature of the microencapsulation reaction is 40~75°C; in some more specific embodiments of the present invention, the temperature of the microencapsulation reaction is 50~70°C.

[0037] In some embodiments of the present invention, the microencapsulation reaction takes 2 to 8 hours; in some specific embodiments of the present invention, the microencapsulation reaction takes 3 to 6 hours; and in some more specific embodiments of the present invention, the microencapsulation reaction takes 3.5 to 5 hours.

[0038] In some embodiments of the present invention, in the mixture of the perfluorinated compound, the additive and water, the mass ratio of the perfluorinated compound to the water is 1:(1~10); for example, it can be any value of 1:1, 1:3, 1:5, 1:7 or 1:10 or any range between two.

[0039] In some embodiments of the present invention, the microencapsulation reaction is followed by steps of filtration, washing, and drying.

[0040] A third aspect of the present invention provides the application of perfluorinated fire extinguishing microcapsules as described in the first aspect of the present invention in the preparation of fire extinguishing devices.

[0041] The beneficial effects of this invention are as follows: This invention uses water-based isocyanate to modify amino resin, resulting in a hybrid amino resin as the wall material. Through the synergistic effect of the wall material components, it overcomes the limitation that single wall material reinforcement and toughening cannot be achieved simultaneously, and also solves the compatibility problem of multilayer coating systems, achieving a simultaneous improvement in the thermal stability and structural integrity of the microcapsules. These microcapsules exhibit good thermal stability and can release the core material when the temperature exceeds a critical value, thereby achieving a good fire extinguishing effect. Attached Figure Description

[0042] Figure 1 This is a SEM image of the sample from Example 1.

[0043] Figure 2 The image shows the SEM image of sample 1 (Comparative Example 1).

[0044] Figure 3 The thermogravimetric curve of the sample in Example 1 is shown. Detailed Implementation

[0045] The following specific embodiments further illustrate the content of the present invention in detail. It should also be understood that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0046] The following examples and comparative examples involve the following raw material information: The aqueous isocyanate contains 25 wt% of the active group -N=C=O (NCO content).

[0047] All parts mentioned in the following examples and comparative examples refer to parts by mass.

[0048] Example 1 A perfluorohexanone fire extinguishing microcapsule, the specific preparation steps of which are as follows: Five parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve them. The pH was adjusted to 9.0 with alkali, and the mixture was reacted in a 70°C water bath for 1 hour. The temperature was then lowered to 40°C, and two parts aqueous isocyanate were added. The reaction continued for 0.5 hours to obtain a viscous, milky-white aqueous isocyanate-modified melamine-urea-formaldehyde prepolymer solution. 100 parts perfluorohexanone, 1 part polyethylene glycol, 10 parts ethylene-maleic anhydride, and 400 parts distilled water were mixed and emulsified under mechanical stirring at 400 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.0, and the prepolymer solution was gradually added to the emulsion. The temperature was slowly raised to 55°C and reacted for 4 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0049] Example 2 A perfluorohexanone fire extinguishing microcapsule, the specific preparation steps of which are as follows: 10 parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve them. The pH was adjusted to 9.5 with alkali, and the mixture was reacted in a 70°C water bath for 1 hour. The temperature was then lowered to 50°C, and 4 parts aqueous isocyanate were added. The reaction continued for 0.5 hours to obtain a viscous, milky-white aqueous isocyanate-modified melamine-urea-formaldehyde prepolymer solution. 150 parts perfluorohexanone, 2 parts nonylphenol polyoxyethylene ether, 15 parts sodium dodecyl sulfate, and 500 parts distilled water were mixed and emulsified under mechanical stirring at 300 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.2, and the prepolymer solution was gradually added to the emulsion. The temperature was slowly raised to 65°C and reacted for 4 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0050] Example 3 A perfluorohexanone fire extinguishing microcapsule, which reduces the amount of melamine used compared to Example 1, is prepared as follows: 2.5 parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve the mixture. The pH was adjusted to 9.0 with alkali, and the mixture was reacted in a 70℃ water bath for 1 hour. The temperature was then lowered to 40℃, and 2 parts aqueous isocyanate were added. The reaction continued for 0.5 hours to obtain a viscous, milky-white aqueous isocyanate-modified melamine-urea-formaldehyde prepolymer solution. 100 parts perfluorohexanone, 1 part polyethylene glycol, 10 parts ethylene-maleic anhydride, and 400 parts distilled water were mixed and emulsified under mechanical stirring at 400 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.0, and the prepolymer solution was gradually added to the emulsion. The temperature was slowly raised to 55℃ and reacted for 4 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0051] Example 4 A perfluorohexanone fire extinguishing microcapsule, with an increased pH during the microencapsulation reaction compared to Example 1, is prepared as follows: Five parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve them. The pH was adjusted to 9.0 with alkali, and the mixture was reacted in a 70°C water bath for 1 hour. The temperature was then lowered to 40°C, and two parts aqueous isocyanate were added. The reaction continued for 0.5 hours to obtain a viscous, milky-white aqueous isocyanate-modified melamine-urea-formaldehyde prepolymer solution. 100 parts perfluorohexanone, 1 part polyethylene glycol, 10 parts ethylene-maleic anhydride, and 400 parts distilled water were mixed and emulsified under mechanical stirring at 400 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.2, and the prepolymer solution was gradually added to the emulsion. The temperature was slowly raised to 55°C and reacted for 4 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0052] Example 5 A perfluorohexanone fire extinguishing microcapsule, which lowers the reaction temperature compared to Example 1, is prepared using the following steps: Five parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve them. The pH was adjusted to 9.0 with alkali, and the mixture was reacted in a 70°C water bath for 1 hour. The temperature was then lowered to 40°C, and two parts aqueous isocyanate were added. The reaction continued for 0.5 hours to obtain a viscous, milky-white aqueous isocyanate-modified melamine-urea-formaldehyde prepolymer solution. 100 parts perfluorohexanone, 1 part polyethylene glycol, 10 parts ethylene-maleic anhydride, and 400 parts distilled water were mixed and emulsified under mechanical stirring at 400 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.0, and the prepolymer solution was gradually added to the emulsion. The temperature was slowly raised to 40°C and reacted for 4 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0053] Example 6 A perfluorohexanone fire extinguishing microcapsule, which reduces the amount of aqueous isocyanate used compared to Example 1, is prepared as follows: Five parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve them. The pH was adjusted to 9.0 with alkali, and the mixture was reacted in a 70°C water bath for 1 hour. The temperature was then lowered to 40°C, and one part aqueous isocyanate was added. The reaction continued for 0.5 hours to obtain a viscous, milky-white aqueous isocyanate-modified melamine-urea-formaldehyde prepolymer solution. 100 parts perfluorohexanone, 1 part polyethylene glycol, 10 parts ethylene-maleic anhydride, and 400 parts distilled water were mixed and emulsified under mechanical stirring at 400 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.0, and the prepolymer solution was gradually added to the emulsion. The temperature was slowly raised to 55°C and reacted for 4 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0054] Example 7 A perfluorohexanone fire extinguishing microcapsule, which shortens the reaction time compared to Example 1, is prepared using the following steps: Five parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve them. The pH was adjusted to 9.0 with alkali, and the mixture was reacted in a 70°C water bath for 1 hour. The temperature was then lowered to 40°C, and two parts aqueous isocyanate were added. The reaction continued for 0.5 hours to obtain a viscous, milky-white aqueous isocyanate-modified melamine-urea-formaldehyde prepolymer solution. One hundred parts perfluorohexanone, one part polyethylene glycol, ten parts ethylene-maleic anhydride, and 400 parts distilled water were mixed and emulsified under mechanical stirring at 400 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.0, and the prepolymer solution was gradually added to the emulsion. The temperature was slowly raised to 55°C and reacted for 3 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0055] Comparative Example 1 A perfluorohexanone fire extinguishing microcapsule, which, compared to Example 1, does not use aqueous isocyanate modification, is prepared using the following specific steps: Five parts melamine, 40 parts urea, and 150 parts formaldehyde were used as wall materials. 50 parts distilled water were added and heated to dissolve the mixture. The pH was adjusted to 9.0 with alkali, and the mixture was reacted in a 70°C water bath for 1 hour to obtain a viscous and transparent melamine-urea-formaldehyde prepolymer solution. 100 parts perfluorohexanone, 1 part polyethylene glycol, 10 parts ethylene-maleic anhydride, and 400 parts distilled water were mixed and emulsified under mechanical stirring at 400 rpm for 10 minutes to form a homogeneous emulsion. The pH was then adjusted to 3.0, and the prepolymer solution was gradually added to the emulsion. The mixture was slowly heated to 55°C and reacted for 4 hours to perform microencapsulation. After washing, filtration, and drying, perfluorohexanone fire extinguishing microcapsules were obtained.

[0056] Performance testing The performance of the perfluorohexanone fire extinguishing microcapsules in each embodiment and comparative example was tested, as follows: 1. Morphological test Take a small amount of the perfluorohexanone fire extinguishing microcapsule sample from Example 1 (about 0.1 g), disperse it on conductive tape, and observe the morphology of the perfluorohexanone fire extinguishing microcapsule using a scanning electron microscope (SEM).

[0057] 2. Thermal weight loss rate test: Using a thermogravimetric analyzer, the perfluorohexanone fire extinguishing microcapsule sample (approximately 10 mg) from Example 1 was sealed in an alumina crucible at a nitrogen temperature of 25–600 °C, and the thermogravimetric rate was tested at a heating rate of 10 °C / min.

[0058] 3. Thermal stability test Each example and comparative sample of perfluorohexanone fire extinguishing microcapsule (2 g) was placed in a glass sample bottle and incubated at 80°C for 30 min for thermal stability testing. In this invention, the thermal stability of the perfluorohexanone fire extinguishing microcapsule was evaluated by the mass retention rate after incubation at a given temperature for a certain period of time. A high mass retention rate indicates high thermal stability of the perfluorohexanone fire extinguishing microcapsule. The calculation formula is: Mass retention rate = (Mass of sample after test / Mass of sample before test) × 100%.

[0059] Figure 1 Here is a SEM image of the sample from Example 1; Figure 2 This is a SEM image of sample 1 (Comparative Example 1). Figures 1-2As can be seen, the perfluorohexanone fire extinguishing microcapsules prepared in Example 1 exhibit a regular spherical structure with full particles, smooth outlines, and particle sizes in the range of 200-500 μm. Compared with Example 1, the surface of the sample in Comparative Example 1 is rougher, indicating that the water-based isocyanate modification promotes a denser (enhanced) crosslinking of melamine-formaldehyde-urea and introduces flexible segments (toughening), resulting in a more uniform polymerization process (smoother surface).

[0060] In Example 1, aqueous isocyanate was added during monomer polymerization. The prepolymer formed by the monomer contained a large number of unreacted hydroxymethyl and active amino groups. The -NCO groups of the isocyanate could chemically crosslink with these active groups to form covalently linked amino resin prepolymer-isocyanate composite molecular chains. Further coating with these chains achieved a good modification effect from the aqueous isocyanate. However, if fully polymerized amino resin was mixed with aqueous isocyanate, the amino resin molecular chains had already formed a stable crosslinked structure, and the active groups were essentially exhausted. Effective chemical crosslinking was impossible; only physical blending occurred, failing to achieve substantial isocyanate modification. The effect was equivalent to no isocyanate modification (Comparative Example 1).

[0061] Figure 3 The thermogravimetric curve of the sample from Example 1. Figure 3 As can be seen, the perfluorohexanone fire extinguishing microcapsules prepared in Example 1 only lost 1.81% of their weight at 80°C, demonstrating good thermal stability.

[0062] Table 1 shows the thermal stability test data of samples from Examples 1-8 and Comparative Example 1. As can be seen from Table 1, the samples in the examples have good thermal stability.

[0063] Table 1 Thermal stability test data of samples from Examples 1-8 and Comparative Example 1

[0064] In summary, this invention utilizes aqueous isocyanate to modify amino resin, resulting in a hybrid amino resin as the wall material. Through the synergistic effect of these wall material components, it overcomes the limitation that single wall material reinforcement and toughening cannot be simultaneously achieved, while also resolving the compatibility issue of multilayer encapsulation systems. This results in a simultaneous improvement in the thermal stability and structural integrity of the microcapsules. The microcapsules exhibit good thermal stability, releasing the core material only when the temperature exceeds a critical value (>100℃), thus achieving a good fire extinguishing effect. Specifically, the microcapsules in Example 1 maintain a high mass retention rate (>75%) even at 100℃; as the temperature increases, the microcapsule structure gradually disintegrates, allowing for controlled release of the core material, ultimately demonstrating a good fire extinguishing effect.

[0065] Furthermore, this invention employs a one-step in-situ polymerization method to coat the surface of a perfluorinated compound with a hybrid amino resin, offering advantages in both performance and cost. This one-step coating method avoids the high costs associated with multiple coating processes and possesses the potential for large-scale production. The resulting perfluorinated fire extinguishing microcapsules also exhibit excellent thermal stability.

Claims

1. A perfluorinated fire extinguishing microcapsule, characterized in that, The device includes a core material, a wall material, and additives; the wall material covers at least a portion of the surface of the core material; the additives are disposed at least at the interface between the core material and the wall material; the core material includes a perfluorinated compound; the wall material includes a hybrid amino resin; the hybrid amino resin is obtained by modifying an amino resin with an aqueous isocyanate.

2. The perfluorinated fire extinguishing microcapsule according to claim 1, characterized in that, The aqueous isocyanate is covalently linked to the amino resin; And / or, the amino resin includes at least one of melamine-formaldehyde-urea resin, melamine-formaldehyde resin, or urea-formaldehyde resin; the melamine content in the melamine-formaldehyde-urea resin is 0.1~20 wt%; And / or, the NCO content of the aqueous isocyanate is 20-30 wt%; And / or, the amount of the aqueous isocyanate is 0.4 to 5 wt% of the mass of the amino resin.

3. The perfluorinated fire extinguishing microcapsule according to claim 1, characterized in that, The perfluorinated compounds include C3-C8 perfluoroketones, C3-C8 perfluoroalkanes, or combinations thereof.

4. The perfluorinated fire extinguishing microcapsule according to claim 3, characterized in that, The perfluorinated compound includes at least one of perfluorohexanone, perfluoroacetone, perfluorobutanone, perfluoropentanone, perfluoropropane, perfluorobutane, perfluoropentane, perfluorohexane, perfluoroheptane, or perfluorooctane.

5. The perfluorinated fire extinguishing microcapsule according to claim 1, characterized in that, The perfluorinated fire extinguishing microcapsules have a particle size of 100~600μm; And / or, the mass ratio of the core material to the wall material is 1:(0.8~3).

6. The perfluorinated fire extinguishing microcapsule according to claim 1, characterized in that, The additive includes a surfactant; the surfactant is selected from nonionic surfactants, anionic surfactants, or combinations thereof; the hydrophilic group of the nonionic surfactant includes at least one of a polyoxyethylene chain and a polyol hydroxyl group; the hydrophilic group of the anionic surfactant includes at least one of a sulfonic acid group, a sulfate ester group, or a carboxyl group.

7. A method for preparing a perfluorinated fire extinguishing microcapsule, characterized in that, Includes the following steps: A mixture of amino monomers, aldehyde compounds, aqueous isocyanates, and water is reacted to obtain a hybrid amino resin prepolymer; a perfluorinated compound, additives, and water are mixed to form a solution containing a core material; the hybrid amino resin prepolymer is mixed with the solution containing the core material to carry out a microencapsulation reaction, and after drying, a perfluorinated fire extinguishing microcapsule as described in any one of claims 1 to 6 is obtained.

8. The preparation method according to claim 7, characterized in that, The amino-containing monomers include melamine, urea, or combinations thereof; And / or, the aldehyde compounds include at least one of formaldehyde, acetaldehyde, or butyraldehyde.

9. The preparation method according to claim 7, characterized in that, The pH of the microencapsulation reaction is 2.5~3.5; And / or, the temperature of the microencapsulation reaction is 40~60℃.

10. The application of a perfluorinated fire extinguishing microcapsule as described in any one of claims 1 to 6 in the preparation of a fire extinguishing device.

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