Perfluoroacetone microcapsules and methods for their preparation

Abstract

The application provides a perfluoroacetone microcapsule and a preparation method thereof, and belongs to the technical field of fire extinguishing materials, and comprises a core and a shell layer; the core comprises perfluorohexanone and fumed silica; the shell layer comprises isophorone diisocyanate, diethylenetriamine and a chlorine-containing monomer, the isophorone diisocyanate, the diethylenetriamine and the chlorine-containing monomer form a polyurea-polyurethane hybrid network through an interfacial polymerization reaction; the mass ratio of the shell to the core of the microcapsule is 1: (5-20); the oil-in-oil type anhydrous interfacial polymerization system is used to construct the anhydrous microcapsule core, so that the hydrolysis side reaction is fundamentally avoided, the microcapsule has a high stable encapsulation rate, and the reliability and long-term effectiveness of the product in the storage and use processes are ensured.

Description

Technical Field

[0001] This invention belongs to the field of fire extinguishing materials technology, specifically referring to a perfluoroacetone microcapsule and its preparation method. Background Technology

[0002] Perfluorohexanone (chemical formula C5F) 12 Ozone (O2), as a clean and efficient new type of gaseous fire extinguishing agent, has attracted widespread attention due to its zero ozone depletion potential, extremely low global warming potential, and lack of residue after extinguishing fires. Its extinguishing mechanism primarily lies in its ability to rapidly vaporize and capture free radicals in the combustion chain reaction, achieving highly efficient chemical suppression of fires.

[0003] Given its excellent fire extinguishing performance, the industry has long hoped to apply perfluorohexanone to the field of flame retardant materials. For example, it could be encapsulated using microencapsulation technology and dispersed as a functional additive in various matrices to give materials high-temperature triggered active fire extinguishing capabilities. However, successfully microencapsulating perfluorohexanone and achieving long-term stable storage faces several key technical bottlenecks.

[0004] First, the physicochemical properties of perfluorohexanone pose a significant challenge to microencapsulation. Perfluorohexanone has a boiling point of only 49°C and is extremely volatile at room temperature, making it prone to volatilization loss during traditional water-based emulsion polymerization, resulting in low final encapsulation efficiency. Even more problematic is that perfluorohexanone is unstable in the aqueous phase and readily undergoes slow hydrolysis, generating corrosive byproducts such as hydrogen fluoride. This not only corrodes production equipment but also degrades the polymer wall material of the microcapsules, leading to premature leakage and failure during storage.

[0005] Secondly, existing microcapsule wall materials suffer from insufficient compatibility and sealing properties with perfluorohexanone. Common wall materials such as polyurea and melamine resins exhibit weak interfacial bonding with perfluorohexanone, a perfluorinated solvent, making it difficult to form a dense and complete encapsulation layer. This results in microcapsules with low encapsulation efficiency (generally below 87%), severe core material leakage, and poor storage stability. Furthermore, the wall materials of microcapsules often cannot effectively withstand the vapor pressure generated by temperature changes in the internal perfluorohexanone, making them prone to rupture during processing or storage.

[0006] To address the aforementioned issues, especially the challenges of hydrolysis and volatilization posed by aqueous systems, there is an urgent need to develop a novel microencapsulation strategy suitable for perfluorohexanone. Summary of the Invention

[0007] To overcome some of the problems mentioned in the background above, the present invention provides perfluoroacetone microcapsules and a method for preparing the same, so as to at least partially solve the above problems.

[0008] According to the technical solution of the present invention, a perfluoroacetone microcapsule is provided, comprising a core and a shell;

[0009] The core comprises perfluorohexanone and fumed silica;

[0010] The shell layer comprises isoflurane diisocyanate, diethylenetriamine, and chlorine-containing monomers, wherein the isoflurane diisocyanate, diethylenetriamine, and chlorine-containing monomers are formed into a polyurea-polyurethane hybrid network through interfacial polymerization.

[0011] The shell-to-core mass ratio of the microcapsule is 1:(5-20).

[0012] Preferably, the core comprises the following raw materials in parts by weight: 85-95 parts perfluorohexanone and 1-3 parts fumed silica.

[0013] Preferably, the core further includes a diluent, wherein the diluent is 5-15 parts by weight of methyl nonafluorobutyl ether.

[0014] Preferably, the shell layer comprises the following raw materials in parts by weight: 4-8 parts isoflurane diisocyanate, 2-5 parts diethylenetriamine and 1-5 parts chlorine-containing monomer.

[0015] Preferably, the chlorine-containing monomer is a vinyl chloride-hydroxyethyl acrylate copolymer, and the shell surface is introduced with thiol groups that can chemically bond with PVC molecules.

[0016] Preferably, the thiol group is introduced by modifying the surface of the microcapsule with 0.5-2 parts by weight of 3-mercaptopropyltrimethoxysilane via a silane coupling agent or a thiol-containing compound.

[0017] Preferably, the microcapsule further includes 2-5 parts by weight of a chlorine-containing reactive emulsifier, wherein the emulsifier is one or more selected from sodium perfluorononenoxybenzenesulfonate, hexadecyltrimethylammonium chloride, and dodecyldimethylbenzylammonium chloride.

[0018] Preferably, the average particle size of the microcapsules is 3-8 μm, and the thermal response rupture temperature of the microcapsules is 150-180℃.

[0019] Furthermore, the present invention also provides a method for preparing perfluoroacetone microcapsules, comprising the following steps:

[0020] (1) Mix perfluorohexanone, fumed silica, methyl nonafluorobutyl ether, isoflurane diisocyanate and chlorine-containing reactive emulsifier, and perform high-speed shear emulsification at 1500-2500 rpm / min for 10-15 min under an inert atmosphere to obtain an emulsion;

[0021] (2) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly dropwise to the emulsion obtained in step (1) at a rate of 1-2 ml / min, and carry out interfacial polymerization reaction for 3-5 h to form microcapsule initial product;

[0022] (3) Add 3-mercaptopropyltrimethoxysilane to the product obtained in step (2) and react at 55-65°C for 1.5-2.5 h to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder.

[0023] On the other hand, the present invention also provides an application of perfluoroacetone microcapsules, namely, the application of the above-mentioned perfluoroacetone microcapsules in the manufacturing fields of power cables, communication optical cables, new energy vehicle cables or ship cables.

[0024] Microcapsules at a mass percentage of 15-25% are premixed with PVC material and optional additives in a high-speed mixer, then melt-blended at a processing temperature of 150°C and extruded and granulated using a twin-screw extruder.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0026] This invention constructs an anhydrous microcapsule core through an oil-in-oil anhydrous interfacial polymerization system, fundamentally avoiding hydrolysis side reactions, resulting in microcapsules with a high stable encapsulation rate, ensuring the reliability and long-lasting effect of the product during storage and use;

[0027] This invention allows for precise control of the mechanical strength and thermal stability of the microcapsule wall material by adjusting parameters such as the degree of crosslinking between isocyanate and amine, and the shell-core ratio. This enables the rupture temperature to be precisely set within the desired range. By changing the emulsification shear rate, microcapsules of different particle sizes can be prepared. Detailed Implementation

[0028] The technical solutions in the embodiments will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection.

[0029] This invention provides a perfluoroacetone microcapsule, comprising a core and a shell;

[0030] The core comprises perfluorohexanone and fumed silica;

[0031] The shell layer comprises isoflurane diisocyanate, diethylenetriamine, and chlorine-containing monomers, wherein the isoflurane diisocyanate, diethylenetriamine, and chlorine-containing monomers are formed into a polyurea-polyurethane hybrid network through interfacial polymerization.

[0032] The shell-to-core mass ratio of the microcapsule is 1:(5-20).

[0033] In a further embodiment of this example, the core comprises the following raw materials in parts by weight: 85-95 parts of perfluorohexanone and 1-3 parts of fumed silica.

[0034] In a further embodiment of this example, the core also includes a diluent, which is 5-15 parts by weight of methyl nonafluorobutyl ether.

[0035] In a further embodiment of this example, the shell layer comprises the following raw materials in parts by weight: 4-8 parts isoflurane diisocyanate, 2-5 parts diethylenetriamine and 1-5 parts chlorine-containing monomer.

[0036] In a further embodiment of this example, the chlorine-containing monomer is a vinyl chloride-hydroxyethyl acrylate copolymer, and the shell surface is introduced with thiol groups that can chemically bond with PVC molecules.

[0037] In a further embodiment of this example, the thiol group is introduced by modifying the surface of the microcapsule with 0.5-2 parts by weight of 3-mercaptopropyltrimethoxysilane via a silane coupling agent or a thiol-containing compound.

[0038] In a further embodiment of this example, the microcapsule further includes 2-5 parts by weight of a chlorine-containing reactive emulsifier, wherein the emulsifier is one or more of sodium perfluorononenoxybenzenesulfonate, hexadecyltrimethylammonium chloride, and dodecyldimethylbenzylammonium chloride.

[0039] In a further embodiment of this example, the average particle size of the microcapsules is 3-8 μm, and the thermal response rupture temperature of the microcapsules is 150-180°C.

[0040] It should be noted that fumed silica is added to the core as a thixotropic agent to reduce the fluidity of the core material and prevent precipitation and aggregation during storage. When the temperature of the microcapsule rises to or above its rupture temperature, the microcapsule wall softens and expands, and the perfluorohexanone inside vaporizes, generating sufficient pressure to rupture the capsule. The released perfluorohexanone rapidly vaporizes, absorbing a large amount of heat during the vaporization process. At high temperatures, perfluorohexanone decomposes to produce fluorine free radicals (F•, CF3•), which capture key free radicals (H•, OH•) in the combustion chain reaction. The gaseous perfluorohexanone forms a localized inert environment, diluting the oxygen concentration and achieving an active fire extinguishing effect.

[0041] Adding methyl nonafluorobutyl ether as a diluent reduces the saturated vapor pressure of perfluorohexanone, thereby reducing osmotic pressure on the capsule wall during storage and improving storage stability; it also adjusts the viscosity of the core material, which is beneficial for core emulsification.

[0042] Isoflurane diisocyanate (IPDI), as one of the main monomers in the shell, reacts with amines and alcohols to form a polyurea / polyurethane shell. IPDI has steric hindrance, resulting in a slow reaction and easy formation of a dense and tough shell.

[0043] Chlorine-containing reactive emulsifiers can act as emulsifiers to reduce the tension of the oil-in-oil interface and form a stable emulsion. They can also act as compatibilizers to enable the benzene rings and sulfonic acid groups in the molecule to interact with PVC. The chlorine-containing structure is similar to and compatible with PVC, which fundamentally improves the interfacial compatibility between microcapsules and the PVC matrix.

[0044] Diethylenetriamine acts as a curing agent and crosslinking agent. Its amine groups react rapidly with the -NCO groups on IPDI to form a polyurea shell structure with high mechanical strength. It can provide crosslinking points and enhance the solvent resistance and thermal stability of the shell.

[0045] The hydroxyl groups on the vinyl chloride-hydroxyethyl acrylate copolymer react with IPDI to anchor the copolymer in the wall material. In addition, the vinyl chloride segments are highly compatible with the main PVC structure, achieving "molecular-level" entanglement and bonding between the microcapsules and PVC, which greatly improves the interfacial adhesion.

[0046] 3-Mercaptopropyltrimethoxysilane, as a surface modifier, has thiol groups that can form strong CS covalent bonds with unsaturated sites in the PVC molecular chain through "thiol-ene" click chemistry. In addition, the methoxy group can be hydrolyzed to form silanol groups, which can combine with inorganic fillers to achieve "bridging" between microcapsules and the matrix.

[0047] The thiol functional groups on the surface of the microcapsule undergo a click chemical reaction with the double bonds in the PVC molecular chain to form a PVC-microcapsule covalent bond. This solves the problem of poor compatibility between traditional microcapsules and the matrix, significantly improves the mechanical properties of the cable, and solves the problems of interface defects and mechanical property degradation caused by traditional physical mixing.

[0048] Furthermore, this invention also provides a method for preparing perfluoroacetone microcapsules, comprising the following steps:

[0049] (1) Mix perfluorohexanone, fumed silica, methyl nonafluorobutyl ether, isoflurane diisocyanate and chlorine-containing reactive emulsifier, and perform high-speed shear emulsification at 1500-2500 rpm / min for 10-15 min under an inert atmosphere to obtain an emulsion;

[0050] (2) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly dropwise to the emulsion obtained in step (1) at a rate of 1-2 ml / min, and carry out interfacial polymerization reaction for 3-5 h to form microcapsule initial product;

[0051] (3) Add 3-mercaptopropyltrimethoxysilane to the product obtained in step (2) and react at 55-65°C for 1.5-2.5 h to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder.

[0052] It should be noted that the curing agent includes diethylenetriamine, vinyl chloride-hydroxyethyl acrylate copolymer, dibutyltin dilaurate catalyst, and anhydrous xylene. The mass ratio of diethylenetriamine, vinyl chloride-hydroxyethyl acrylate copolymer, dibutyltin dilaurate catalyst, and anhydrous xylene is (15-25):(10-20):(0.1-0.5):(54.5-74.9). The diethylenetriamine ensures a sufficient and slightly excessive amount of amine groups to react with the -NCO groups of IPDI in the oil phase, following the principle of "slightly excessive amine groups" to guarantee complete reaction of IPDI and the formation of a fully crosslinked, non-toxic curing agent. The microcapsule contains a robust wall material with residual unreacted -NCO; the vinyl chloride-hydroxyethyl acrylate copolymer provides sufficient interfacial compatible functional groups to the microcapsule surface without significantly interfering with the main polymerization reaction, achieving excellent interfacial bonding without excessively affecting the formation of the shell matrix; the trace amount of catalyst significantly catalyzes the reaction between -NCO and -OH, ensuring efficient grafting of the vinyl chloride-hydroxyethyl acrylate copolymer; anhydrous xylene as a solvent ensures that all solid and liquid components are fully dissolved, forming a homogeneous and easily transportable solution, while appropriate dilution can control the reaction rate and avoid localized excessively rapid polymerization.

[0053] On the other hand, the present invention also provides an application of perfluoroacetone microcapsules, namely, the application of the perfluoroacetone microcapsules in the manufacturing of power cables, communication optical cables, new energy vehicle cables or ship cables.

[0054] Microcapsules at a mass percentage of 15-25% are premixed with PVC material and optional additives in a high-speed mixer, then melt-blended at a processing temperature of 150°C and extruded and granulated using a twin-screw extruder.

[0055] Example 1

[0056] (1) Mix 90 parts of perfluorohexanone, 2 parts of fumed silica, 5 parts of methyl nonafluorobutyl ether, 5 parts of isoflurane diisocyanate and 2 parts of chlorine-containing reactive emulsifier, and emulsify at high speed of 1500 rpm / min for 13 min under an inert atmosphere to obtain an emulsion.

[0057] (2) Mix 3 parts of diethylenetriamine, 2 parts of vinyl chloride-hydroxyethyl acrylate copolymer, 0.02 parts of dibutyltin dilaurate catalyst and 9 parts of anhydrous xylene to obtain a curing agent solution containing diethylenetriamine and chlorine-containing monomer;

[0058] (3) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly at a rate of 2 ml / min to the emulsion obtained in step (1) and carry out interfacial polymerization reaction for 4 h to form microcapsule initial product;

[0059] (4) Add 1 part of 3-mercaptopropyltrimethoxysilane to the product obtained in step (3) and react at 60°C for 2 hours to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder. The shell-to-core ratio of the microcapsule powder is 1:10, wherein the core particle size is 4.8 μm, the shell thickness is 0.2 μm, and the microcapsule particle size is 5 μm.

[0060] Example 2

[0061] (1) Mix 95 parts of perfluorohexanone, 3 parts of fumed silica, 5 parts of methyl nonafluorobutyl ether, 6 parts of isoflurane diisocyanate and 3 parts of chlorine-containing reactive emulsifier, and emulsify at high speed of 1500 rpm / min for 13 min under an inert atmosphere to obtain an emulsion.

[0062] (2) Mix 3.5 parts of diethylenetriamine, 3 parts of vinyl chloride-hydroxyethyl acrylate copolymer, 0.03 parts of dibutyltin dilaurate catalyst and 10 parts of anhydrous xylene to obtain a curing agent solution containing diethylenetriamine and chlorine-containing monomer;

[0063] (3) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly at a rate of 2 ml / min to the emulsion obtained in step (1) and carry out interfacial polymerization reaction for 4 h to form microcapsule initial product;

[0064] (4) Add 1 part of 3-mercaptopropyltrimethoxysilane to the product obtained in step (3) and react at 60°C for 2 hours to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder. The shell-to-core ratio of the microcapsule powder is 1:15, wherein the core particle size is 7.6 μm, the shell thickness is 0.4 μm, and the microcapsule particle size is 8 μm.

[0065] Example 3

[0066] (1) Mix 85 parts of perfluorohexanone, 1 part of fumed silica, 10 parts of methyl nonafluorobutyl ether, 4 parts of isoflurane diisocyanate and 1 part of chlorine-containing reactive emulsifier, and perform high-speed shear emulsification at 1500 rpm / min for 13 min under an inert atmosphere to obtain an emulsion.

[0067] (2) Mix 2.5 parts of diethylenetriamine, 2 parts of vinyl chloride-hydroxyethyl acrylate copolymer, 0.02 parts of dibutyltin dilaurate catalyst and 9 parts of anhydrous xylene to obtain a curing agent solution containing diethylenetriamine and chlorine-containing monomer;

[0068] (3) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly at a rate of 2 ml / min to the emulsion obtained in step (1) and carry out interfacial polymerization reaction for 4 h to form microcapsule initial product;

[0069] (4) Add 1 part of 3-mercaptopropyltrimethoxysilane to the product obtained in step (3) and react at 60°C for 2 hours to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder. The shell-to-core ratio of the microcapsule powder is 1:8, wherein the core particle size is 5.8 μm, the shell thickness is 0.2 μm, and the microcapsule particle size is 6 μm.

[0070] Example 4

[0071] (1) Mix 90 parts of perfluorohexanone, 2 parts of fumed silica, 5 parts of methyl nonafluorobutyl ether, 5 parts of isoflurane diisocyanate and 2 parts of chlorine-containing reactive emulsifier, and emulsify at high speed of 1500 rpm / min for 13 min under an inert atmosphere to obtain an emulsion.

[0072] (2) Mix 4 parts of diethylenetriamine, 3 parts of vinyl chloride-hydroxyethyl acrylate copolymer, 0.03 parts of dibutyltin dilaurate catalyst and 12 parts of anhydrous xylene to obtain a curing agent solution containing diethylenetriamine and chlorine-containing monomer;

[0073] (3) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly at a rate of 2 ml / min to the emulsion obtained in step (1) and carry out interfacial polymerization reaction for 4 h to form microcapsule initial product;

[0074] (4) Add 1 part of 3-mercaptopropyltrimethoxysilane to the product obtained in step (3) and react at 60°C for 2 hours to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder. The shell-to-core ratio of the microcapsule powder is 1:12, wherein the core particle size is 6.7 μm, the shell thickness is 0.3 μm, and the microcapsule particle size is 7 μm.

[0075] Example 5

[0076] (1) Mix 90 parts of perfluorohexanone, 2 parts of fumed silica, 5 parts of methyl nonafluorobutyl ether, 5 parts of isoflurane diisocyanate and 2 parts of chlorine-containing reactive emulsifier, and perform high-speed shear emulsification at 2500 rpm / min for 13 min under an inert atmosphere to obtain an emulsion.

[0077] (2) Mix 3 parts of diethylenetriamine, 2 parts of vinyl chloride-hydroxyethyl acrylate copolymer, 0.02 parts of dibutyltin dilaurate catalyst and 9 parts of anhydrous xylene to obtain a curing agent solution containing diethylenetriamine and chlorine-containing monomer;

[0078] (3) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly at a rate of 2 ml / min to the emulsion obtained in step (1) and carry out interfacial polymerization reaction for 4 h to form microcapsule initial product;

[0079] (4) Add 1 part of 3-mercaptopropyltrimethoxysilane to the product obtained in step (3) and react at 60°C for 2 hours to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder. The shell-to-core ratio of the microcapsule powder is 1:10, wherein the core particle size is 2.85 μm, the shell thickness is 0.15 μm, and the microcapsule particle size is 3 μm.

[0080] Comparative Example

[0081] Five parts antimony trioxide, 20 parts aluminum hydroxide, and 15 parts chlorinated paraffin-70 were used as extinguishing agents.

[0082] The encapsulation efficiency of the microcapsules obtained in Examples 1-5 was determined using thermogravimetric analysis-gas chromatography (TGA). The total weight loss of the microcapsules was calculated by TGA, and the perfluorohexanone content was quantitatively analyzed by pyrolysis-gas chromatography (PGC). The temperature range in which the microcapsules underwent significant deformation or rupture during heating was observed using a hot-stage microscope coupled with differential scanning calorimetry (DSC), and their thermal response rupture temperature was obtained. The experimental data are shown in Table 1 below.

[0083] Table 1

[0084] Encapsulation rate (%) Rupture temperature (°C) Example 1 93 165 Example 2 96 175 Example 3 91 155 Example 4 93 182 Example 5 92 160

[0085] Cable materials prepared by blending the above Examples 1-5 and the comparative example with PVC material were used as experimental examples. Specifically, 15 wt% microcapsules or fire extinguishing agent, 100 wt% SG-1 type PVC material, 3 wt% calcium-zinc stabilizer, and 40 wt% diisononyl phthalate were premixed in a high-speed mixer, melt-blended at a processing temperature of 150°C, and extruded and granulated using a twin-screw extruder. The limiting oxygen index was determined according to standard ASTM D2863; the heat release rate was determined according to standard ISO 5660-1 using a cone calorimeter; and the tensile strength and elongation at break were determined according to standard ASTM D638. The experimental data are shown in Table 2 below.

[0086] Table 2

[0087] Limiting oxygen index (%) <![CDATA[Heat release peak (kW / m 2 ).]]> Tensile strength (MPa) Self-spontaneous firefighting Example 1 42 80 22.5 yes Example 2 47 65 24.1 yes Example 3 40 95 20.8 yes Example 4 44 75 23.0 yes Example 5 43 85 22.0 ＜3s Comparative Example 32 280 18.5 no

[0088] In summary, by adjusting the shell-to-core ratio, cross-linking degree, particle size, and amount added to PVC, different performance emphases can be achieved, such as high flame retardancy, high flexibility, high temperature resistance, and rapid response. As can be seen from the comparison of the comparative examples and various embodiments, this solution has an active fire protection mechanism that does not exist in the prior art, and the encapsulation rate of over 90% solves the problem of generally low encapsulation rates in the prior art.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A perfluoroacetone microcapsule, characterized in that, The microcapsule has a core-shell structure, comprising a core and a shell. The core comprises perfluorohexanone and fumed silica; The shell layer comprises isoflurane diisocyanate, diethylenetriamine, and chlorine-containing monomers, wherein the isoflurane diisocyanate, diethylenetriamine, and chlorine-containing monomers are formed into a polyurea-polyurethane hybrid network through interfacial polymerization. The shell-to-core mass ratio of the microcapsule is 1:(5-20). The chlorine-containing monomer is a vinyl chloride-hydroxyethyl acrylate copolymer, and the shell surface is introduced with thiol groups that can chemically bond with PVC molecules; The thiol group is introduced by modifying the surface of the microcapsule with 0.5-2 parts by weight of 3-mercaptopropyltrimethoxysilane via a silane coupling agent or a thiol-containing compound. The microcapsules also include 2-5 parts by weight of a chlorine-containing reactive emulsifier, wherein the emulsifier is one or more of sodium perfluorononenoxybenzenesulfonate, hexadecyltrimethylammonium chloride, and dodecyldimethylbenzylammonium chloride.

2. The perfluoroacetone microcapsule according to claim 1, characterized in that, The core comprises the following raw materials in parts by weight: 85-95 parts perfluorohexanone and 1-3 parts fumed silica.

3. The perfluoroacetone microcapsule according to claim 1 or 2, characterized in that, The core also includes a diluent, which is 5-15 parts by weight of methyl nonafluorobutyl ether.

4. The perfluoroacetone microcapsule according to claim 1, characterized in that, The shell layer comprises the following raw materials in parts by weight: 4-8 parts isoflurane diisocyanate, 2-5 parts diethylenetriamine and 1-5 parts chlorine-containing monomer.

5. The perfluoroacetone microcapsule according to claim 1, characterized in that, The average particle size of the microcapsules is 3-8 μm, and the thermal response rupture temperature of the microcapsules is 150-180℃.

6. A method for preparing perfluoroacetone microcapsules according to any one of claims 1-5, characterized in that, Includes the following steps: (1) Mix perfluorohexanone, fumed silica, methyl nonafluorobutyl ether, isoflurane diisocyanate and chlorine-containing reactive emulsifier, and perform high-speed shear emulsification at 1500-2500 rpm / min for 10-15 min under an inert atmosphere to obtain an emulsion; (2) Add a curing agent solution containing diethylenetriamine and chlorine-containing monomers slowly dropwise to the emulsion obtained in step (1) at a rate of 1-2 ml / min, and carry out interfacial polymerization reaction for 3-5 h to form microcapsule initial product; (3) Add 3-mercaptopropyltrimethoxysilane to the product obtained in step (2) and react at 55-65°C for 1.5-2.5 h to introduce thiol functional groups on the surface of the microcapsules. Remove the solvent in the system by supercritical CO2 extraction to obtain dry reactive perfluorohexanone microcapsule powder.

7. An application of a perfluoroacetone microcapsule, characterized in that, Application of perfluoroacetone microcapsules according to any one of claims 1-6 in the manufacturing of power cables, communication optical cables, new energy vehicle cables or ship cables; Microcapsules at a mass percentage of 15-25% are premixed with PVC material and optional additives in a high-speed mixer, then melt-blended at a processing temperature of 150°C and extruded and granulated using a twin-screw extruder.