Multi-core fire extinguishing microcapsule and preparation method thereof

Abstract

The invention relates to the technical field of fire prevention, in particular to a multi-core fire extinguishing microcapsule and a preparation method thereof. The multi-core fire extinguishing microcapsule provided by the invention comprises a microcapsule A, a shell material of the microcapsule A is melamine resin A, and a core material of the microcapsule A is a mixture of a microcapsule B and a fire extinguishing agent A; the shell material of the microcapsule B is melamine resin B, and the core material of the microcapsule B is a fire extinguishing agent B. The outer wall of the large-particle-size multi-core microcapsule is thin, a part of the fire extinguishing agent A is released at a relatively low temperature, the fire can be prevented from happening by timely cooling when the temperature rises and a fire risk occurs, and the inner small-particle-size microcapsule B can be broken and released at a relatively high temperature, so that the subsequent fire extinguishing performance failure caused by releasing a large amount of the fire extinguishing agent at one time at a certain temperature is avoided; and the fire extinguishing cycle use frequency is increased, and the requirements of more fire extinguishing scenes can be met.

Description

Technical Field

[0001] This application relates to the field of fire prevention technology, and particularly to a multi-core fire extinguishing microcapsule and a preparation method thereof. Background Art

[0002] With the development of economy and the progress of technology, electrical equipment plays an increasingly important role in people's lives. From households to workplaces, from transportation vehicles to public facilities, the wide application of electrical equipment has brought great convenience to life. However, the resulting electrical safety problems have become increasingly prominent, and the most serious one is electrical fires.

[0003] The root cause of electrical fire accidents is that the fire sources are mainly concentrated in distribution boxes, power distribution cabinets, sockets, battery packs, electrical appliances, etc. The space is enclosed and relatively small, and it is difficult to detect incipient fires. Although most fire sites are equipped with fire-fighting facilities such as portable fire extinguishers, due to the failure to detect incipient fires in time, or someone discovers an incipient fire but fails to carry out timely and effective extinguishment, the best fire extinguishing opportunity is missed.

[0004] Microcapsule fire extinguishing technology is a current research hotspot and an important development direction for solving the problems of extinguishing incipient fires in new energy and electrical applications. It can effectively solve the problems that new environmentally friendly fire extinguishants such as perfluoromethylcyclohexanone are easy to volatilize and difficult to store and apply. Patent CN 114618111B discloses a perfluoromethylcyclohexanone fire extinguishing microcapsule, which uses urea-formaldehyde resin as the shell material to coat perfluoromethylcyclohexanone to prepare fire extinguishing microcapsules. A fluorine-free emulsifier is used to emulsify perfluoromethylcyclohexanone. The surface energy of perfluoromethylcyclohexanone is extremely low, and the emulsification effect will be poor. The encapsulation rate of the prepared capsules is not high, and the fire extinguishing agent content in the capsules is low, resulting in limited fire extinguishing effect. Patent CN114307028A discloses a fire extinguishing microcapsule core material, a fire extinguishing microcapsule and a preparation method thereof. After using chitosan / sodium alginate to coat the fire extinguishing agent, a layer of polyacrylate shell is coated on its surface to form a double-layer shell material system. When performing secondary coating, in order to reduce the volatilization of the fire extinguishing agent, the polymerization reaction temperature is very low, and it takes a very long reaction time to initiate polymerization using initiators such as potassium persulfate, and the entire process takes a long time. Summary of the Invention

[0005] An embodiment of this application provides a multi-core fire extinguishing microcapsule. Inside the large-particle-size microcapsule A, the small-particle-size microcapsule B and the fire extinguishing agent A are wrapped. When the temperature rises and there is a risk of fire, the outer shell material ruptures, releasing the fire extinguishing agent A to cool down in time. When the temperature further rises after the outer fire extinguishing agent A is completely released, the internal small-particle-size microcapsule B ruptures and releases the fire extinguishing agent B to extinguish the fire, achieving a gradient fire extinguishing effect.

[0006] In a first aspect, the present application provides a multi-core fire extinguishing microcapsule, including microcapsule A, whose shell material is melamine resin A and core material is a mixture of microcapsule B and fire extinguishing agent A; the shell material of the microcapsule B is melamine resin B and the core material is fire extinguishing agent B.

[0007] In some embodiments, the fire extinguishing agent A and the fire extinguishing agent B are independently selected from one or more of perfluorohexanone, perfluorohexane, perfluoroheptane, perfluorooctane, tetrafluorodibromoethane, and trifluorotrichloroethane.

[0008] In some embodiments, the mass ratio of the microcapsule B to the fire extinguishing agent A is 0.3 - 3:1.

[0009] In a second aspect, the present application further provides a preparation method of the above multi-core fire extinguishing microcapsule, including the following steps:

[0010] Step S101: Add the fire extinguishing agent B to an aqueous solution of emulsifier B for mixing and emulsification, then add water-soluble melamine prepolymer B, add acid solution B to adjust the pH value, heat for reaction, and after the reaction ends, dry to obtain microcapsule B;

[0011] Step S102: Disperse the microcapsule B in the fire extinguishing agent A to obtain a dispersion; add the dispersion to an aqueous solution of emulsifier A for mixing and emulsification, then add water-soluble melamine prepolymer A, add acid solution A to adjust the pH value, heat for reaction, and after the reaction ends, dry to obtain the multi-core fire extinguishing microcapsule.

[0012] In some embodiments, the emulsifier A and the emulsifier B are independently selected from one or more mixtures of sodium perfluorononenyloxybenzenesulfonate, Chemours FS64, FS30, FS61, FS60, FS3000, Merck FL2300, and 3M FC4430.

[0013] In some embodiments, the water-soluble melamine prepolymer A and the water-soluble melamine prepolymer B are independently selected from one or more mixtures of Cytec 385, Xinli MF4750, and Shanghai Shuaike SK5710.

[0014] In some embodiments, the acid solution A and the acid solution B are independently selected from one or more mixtures of citric acid, acrylic acid, acetic acid, dilute sulfuric acid, and dilute hydrochloric acid.

[0015] In some embodiments, the mass ratio of the emulsifier B to the fire extinguishing agent B and the mass ratio of the emulsifier A to the fire extinguishing agent A are each independently 0.03 - 0.15:1; the mass ratio of the water-soluble melamine prepolymer A to the fire extinguishing agent A and the mass ratio of the water-soluble melamine prepolymer B to the fire extinguishing agent B are each independently 0.3 - 1:1.

[0016] In some embodiments, in step S101, an acid solution B is added to adjust the pH value to 3-6, the temperature for the heating reaction is 40-60 °C, and the temperature for drying is 40-80 °C.

[0017] In some embodiments, in step S102, an acid solution A is added to adjust the pH value to 3-6, the temperature for the heating reaction is 40-60 °C, and the temperature for drying is 40-80 °C.

[0018] In some embodiments, the mass ratio of emulsifier A to the dispersion liquid is 0.01-0.1:1; the mass ratio of water-soluble melamine prepolymer A to the dispersion liquid is 0.2-0.7:1.

[0019] In this application, melamine resin B is used as the shell material, and low-boiling liquid fire extinguishing agent B is used as the core material. After the fire extinguishing agent B is highly emulsified into small droplets under the action of emulsifier B, melamine resin B is added for coating to form microcapsules B with small particle sizes. The amount of fire extinguishing agent B encapsulated in the microcapsules B with small particle sizes is relatively small, and the pressure generated by the vaporization of the fire extinguishing agent B is also relatively small. Therefore, the microcapsules B with small particle sizes can rupture and release at higher temperatures. The prepared microcapsules B with small particle sizes are redispersed in fire extinguishing agent A as the oil-phase core material, emulsified by emulsifier A, and then coated with melamine resin A on the outside to form large-sized multi-core fire extinguishing microcapsules. The large-sized microcapsules A can encapsulate more fire extinguishing agent A and can extinguish fires more efficiently when a fire breaks out. The fire extinguishing agent contained in the large-sized microcapsules A includes the fire extinguishing agent B inside the microcapsules B with small particle sizes and the fire extinguishing agent A in this intermediate layer outside the microcapsules B with small particle sizes and inside the large-sized microcapsules A. Only the fire extinguishing agent A in the intermediate layer generates pressure on the outer shell material. Compared with single-core fire extinguishing microcapsules of the same size and the same fire extinguishing agent content, the pressure borne by the outer shell of the multi-core fire extinguishing microcapsules is greatly reduced, avoiding the problem that the large-sized microcapsules A start to rupture and release at relatively low temperatures before reaching the fire risk and cannot achieve a good fire extinguishing effect. Due to the protection of the outermost shell material, the fire extinguishing agent B inside the small-sized microcapsules B will be released only after the fire extinguishing agent A in the intermediate layer is released when the outer shell material ruptures. By controlling the content distribution of the fire extinguishing agent in the intermediate layer and the interior and the thickness of the inner and outer shell layers, the fire extinguishing agent A in the intermediate layer can be released in a timely manner when the temperature rises and there is a fire risk, preventing the occurrence of a fire, and the fire extinguishing agent B inside the small-sized microcapsules B can cope with the further rise in temperature after the complete release of the fire extinguishing agent A in the intermediate layer, or the temperature has dropped for the next fire risk, increasing the number of times of fire extinguishing recycling.

[0020] The beneficial effects brought by the technical solution provided by this application include:

[0021] 1. The particle size of the multi-core fire extinguishing microcapsules of this application is increased to about 200 μm, significantly increasing the fire extinguishing agent content to more than 87%. With the same addition amount of microcapsules, a more excellent fire extinguishing effect can be achieved;

[0022] 2. This application adopts a multi-core fire-extinguishing microcapsule structure. Since part of the fire extinguishing agent is encapsulated in the inner microcapsules B with small particle sizes, the pressure generated by a large amount of the fire extinguishing agent turning into gas and bursting the outer shell material is reduced, the heat resistance of the microcapsules is improved, and the problem that it is difficult to balance the high content of the fire extinguishing agent in the microcapsules and the poor heat resistance is solved.

[0023] 3. The outer wall of the large-particle-size multi-core microcapsules is relatively thin, and part of the fire extinguishing agent A is released at a relatively low temperature, which can timely cool down to prevent the occurrence of fire when the temperature rises and there is a risk of fire. The inner microcapsules B with small particle sizes can rupture and release only at a relatively high temperature, avoiding the failure of the subsequent fire extinguishing performance caused by the one-time release of a large amount of the fire extinguishing agent at a certain temperature, increasing the number of times of fire extinguishing recycling, and meeting the requirements of more fire extinguishing scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 Schematic diagram of the microcapsule structure of Embodiment 1 of this application;

[0026] Figure 2 Optical microscope image of the microcapsules of Embodiment 1 of this application;

[0027] Figure 3 Weight loss curve diagram of the microcapsules prepared in Embodiment 1 and Comparative Example 1 of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] To make the purpose, technical solutions, and advantages of the embodiments of this application clearer, the following will clearly and completely describe the technical solutions in the embodiments of this application with reference to the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, rather than all of them. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of this application.

[0029] The embodiments of this application provide a multi-core fire-extinguishing microcapsule, which can solve the problems of low content of the fire extinguishing agent in the fire-extinguishing microcapsules in the prior art and limited fire extinguishing effect.

[0030] The embodiments of this application provide a preparation method for a multi-core fire-extinguishing microcapsule, including the following steps:

[0031] Step S101: Prepare a solution with a mass concentration of 5 - 20% of emulsifier B and water as the aqueous phase. Add fire extinguishing agent B at 20 - 30°C and mix and emulsify for 5 - 30 min. Add water-soluble melamine prepolymer B, and add acid solution B to adjust the pH of the system to 3 - 6. Stir and react for 4 - 6 h, raise the temperature to 40 - 60°C and continue to react for 1 - 3 h to end the reaction. Cool down, wash, filter, and then place in an oven at 40 - 80°C for baking for 10 - 20 h to obtain microcapsule B with small particle size.

[0032] Step S102: Disperse microcapsule B into fire extinguishing agent A to obtain a dispersion. Add the dispersion into a solution with a mass concentration of 5 - 20% prepared from emulsifier A and water, stir and emulsify at 20 - 30°C for 5 - 30 min, add water-soluble melamine prepolymer A, add acid solution A to adjust the pH of the system to 3 - 6, stir and react for 4 - 6 h, raise the temperature to 40 - 60°C and continue to react for 1 - 3 h to end the reaction. Cool down, wash, filter, and then place in an oven at 40 - 80°C for baking for 10 - 20 h to obtain multi-core fire extinguishing microcapsule powder.

[0033] The structural schematic diagram of the multi-core fire extinguishing microcapsules prepared in this application is shown in Figure 1 , Figure 1 where 11 represents melamine resin A, 12 represents fire extinguishing agent A, 21 represents melamine resin B, and 22 represents fire extinguishing agent B.

[0034] The following will elaborate on the multi-core fire extinguishing microcapsules and their preparation method provided in this application in combination with examples and comparative examples.

[0035] Example 1:

[0036] (1) Weigh 4 g of perfluorononenyloxybenzenesulfonate and water to prepare a solution with a mass concentration of 5% as the aqueous phase. Add 40 g of perfluorohexanone at 20°C and mix and emulsify for 15 min. Add 15 g of Cytec 385, adjust the pH of the system to 3.8 with hydrochloric acid, stir and react for 5 h, raise the temperature to 45°C and continue to react for 2 h to end the reaction. Cool down, wash, filter, and then place in an oven at 60°C for baking for 18 h to obtain microcapsule B powder with small particle size.

[0037] (2) Disperse 30 g of the prepared microcapsule B powder into 50 g of perfluorohexanone to obtain a dispersion. Add the dispersion into a solution with a mass concentration of 10% prepared from 4 g of perfluorononenyloxybenzenesulfonate and water, stir and emulsify at 20°C for 10 min. Add 24 g of Cytec 385, adjust the pH of the system to 3.4 with hydrochloric acid, stir and react for 5 h, raise the temperature to 60°C and continue to react for 1 h to end the reaction. Cool down, wash, filter, and then place in an oven at 60°C for baking for 18 h to obtain multi-core fire extinguishing microcapsule powder.

[0038] The optical microscope image of the multi-core fire extinguishing microcapsules prepared in Example 1 is shown in Figure 2 , from Figure 2It can be seen that the microcapsules prepared in Example 1 are of a multi-core structure, and the microcapsules B with small particle sizes are wrapped inside the microcapsules A.

[0039] Example 2:

[0040] (1) Weigh 2 g of perfluorononenyloxybenzenesulfonate and make it into a solution with a mass concentration of 10% in water as the aqueous phase. Add 40 g of perfluorohexanone at 20°C and mix and emulsify for 20 min. Then add 24 g of Cytec 385, adjust the pH of the system to 4.3 with hydrochloric acid, stir and react for 5 h, raise the temperature to 40°C and continue to react for 1 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 50°C and bake for 20 h to obtain the microcapsule B powder with small particle sizes;

[0041] (2) Disperse 30 g of the prepared microcapsule B powder into 40 g of perfluorohexanone to obtain a dispersion. Add the dispersion to a solution with a mass concentration of 10% prepared from 1.4 g of Chemours FS61 and water. Stir and emulsify at 20°C for 10 min, add 21 g of Cytec 385, adjust the pH of the system to 3.7 with hydrochloric acid, stir and react for 4 h, raise the temperature to 40°C and continue to react for 1.5 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 50°C and bake for 20 h to obtain the multi-core fire-extinguishing microcapsule powder.

[0042] Example 3:

[0043] (1) Weigh 4 g of Chemours FS60 and make it into a solution with a mass concentration of 10% in water as the aqueous phase. Add 40 g of perfluorohexane at 30°C and mix and emulsify for 10 min. Then add 28 g of Cytec 385, adjust the pH of the system to 4.3 with acetic acid, stir and react for 5 h, raise the temperature to 60°C and continue to react for 1 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 70°C and bake for 15 h to obtain the microcapsule B powder with small particle sizes;

[0044] (2) Disperse 30 g of the prepared microcapsule B powder into 30 g of perfluorohexane to obtain a dispersion. Add the dispersion to a solution with a mass concentration of 15% prepared from 1.8 g of Chemours FS60 and water. Stir and emulsify at 30°C for 10 min, add 18 g of Xinli MF4750, adjust the pH of the system to 4 with acetic acid, stir and react for 6 h, raise the temperature to 60°C and continue to react for 1 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 70°C and bake for 15 h to obtain the multi-core fire-extinguishing microcapsule powder.

[0045] Example 4:

[0046] (1) Weigh 4 g of Merck FL2300 and mix it with water to prepare a solution with a mass concentration of 15% as the aqueous phase. Add 40 g of perfluoromethylcyclohexanone at 20 °C and mix and emulsify for 20 min. Then add 20 g of Cytec 385, adjust the pH of the system to 3.2 with sulfuric acid, stir and react for 4 h. Raise the temperature to 45 °C and continue to react for 2 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 60 °C and bake for 16 h to obtain microcapsule B powder with a small particle size;

[0047] (2) Disperse 30 g of the prepared microcapsule B powder into 40 g of perfluoromethylcyclohexanone to obtain a dispersion. Add the dispersion to a solution with a mass concentration of 5% prepared from 2.1 g of Chemours FS60 and water, stir and emulsify at 20 °C for 10 min. Then add 28 g of Shuaike SK5710, adjust the pH of the system to 3.2 with sulfuric acid, stir and react for 4 h. Raise the temperature to 45 °C and continue to react for 3 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 60 °C and bake for 16 h to obtain multi-core fire-extinguishing microcapsule powder.

[0048] Comparative Example 1:

[0049] (1) Weigh 4 g of perfluorononyloxybenzenesulfonate and mix it with water to prepare a solution with a mass concentration of 5% as the aqueous phase. Add 40 g of perfluoromethylcyclohexanone at 20 °C and mix and emulsify for 15 min. Then add 15 g of Cytec 385, adjust the pH of the system to 3.8 with hydrochloric acid, stir and react for 5 h. Raise the temperature to 45 °C and continue to react for 2 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 60 °C and bake for 18 h to obtain microcapsule B powder with a small particle size;

[0050] (2) Add 80 g of perfluoromethylcyclohexanone to a solution with a mass concentration of 10% prepared from 4 g of perfluorononyloxybenzenesulfonate and water, stir and emulsify at 20 °C for 10 min. Then add 24 g of Cytec 385, adjust the pH of the system to 3.4 with hydrochloric acid, stir and react for 5 h. Raise the temperature to 60 °C and continue to react for 1 h to end the reaction. After cooling, washing, and suction filtration, place it in an oven at 60 °C and bake for 18 h to obtain fire-extinguishing microcapsule powder.

[0051] Perform performance tests on the microcapsules prepared in Examples 1-4 and Comparative Example 1, and the results are shown in Table 1.

[0052] Table 1: Performance test results of the microcapsules prepared in Examples 1-4 and Comparative Example 1

[0053]

[0054]

[0055] In the above embodiments, the microcapsules prepared in Embodiment 1 have the largest particle size and the highest content of the encapsulated fire extinguishing agent. The particle size and core material content of Comparative Example 1 are not much different from those of Embodiment 1. About 5 g of microcapsule powder was weighed and placed in an oven. After being placed at different temperatures of 80 - 200 °C for 10 min, the weight loss of the microcapsules at different temperatures was measured, and Figure 3 was obtained. The weight loss of the microcapsules at different temperatures is the amount of the fire extinguishing agent released at different temperatures. As can be seen from Figure 3 , for the single-core microcapsules prepared in Comparative Example 1, almost all of them had been released at 120 °C. With too large a particle size, a large amount of the encapsulated fire extinguishing agent was released before the fire risk was reached. For the multi-core structure microcapsules prepared in Embodiment 1, only a small amount of the core material was released below 120 °C, part was released at 120 - 140 °C, and another part was released at 140 - 180 °C. The heat resistance of the microcapsules was significantly improved, and there was an effect of gradient release for fire extinguishing.

[0056] In the description of this specification, the descriptions referring to terms such as "one embodiment / way", "some embodiments / ways", "example", "specific example", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with that embodiment / way or example are included in at least one embodiment / way or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments / ways or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments / ways or examples described in this specification and the features of different embodiments / ways or examples.

[0057] It should be noted that in the present application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including", or any other variant thereof is intended to cover a non-exclusive inclusion, such that a process, method, article, or device including a series of elements not only includes those elements but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article, or device. Without further limitation, an element defined by the statement "including one..." does not exclude the existence of additional identical elements in the process, method, article, or device including the said element. In the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0058] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but rather will be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A multi-core fire-extinguishing microcapsule, characterized in that, It includes microcapsule A, whose shell material is melamine resin A and core material is a mixture of microcapsule B and fire extinguishing agent A; the shell material of the microcapsule B is melamine resin B and the core material is fire extinguishing agent B.

2. The multi-core fire-extinguishing microcapsule according to claim 1, wherein The fire extinguishing agent A and the fire extinguishing agent B are independently selected from one or more of perfluorohexanone, perfluorohexane, perfluoroheptane, perfluorooctane, tetrafluorodibromoethane, and trifluorotrichloroethane.

3. The multi-core fire extinguishing microcapsule according to claim 1, characterized in that, The mass ratio of the microcapsule B to the fire extinguishing agent A is 0.3 - 3:

1.

4. The preparation method of the multi-core fire-extinguishing microcapsules according to any one of claims 1 to 3, characterized in that, It includes the following steps: S101, adding the fire extinguishing agent B into the aqueous solution of emulsifier B for mixing and emulsifying, then adding water-soluble melamine prepolymer B, adding acid solution B to adjust the pH value, heating for reaction, and after the reaction ends, drying to obtain the microcapsule B; S102, dispersing the microcapsule B in the fire extinguishing agent A to obtain a dispersion; adding the dispersion into the aqueous solution of emulsifier A for mixing and emulsifying, then adding water-soluble melamine prepolymer A, adding acid solution A to adjust the pH value, heating for reaction, and after the reaction ends, drying to obtain the multi-core fire extinguishing microcapsule.

5. The preparation method of the multi-core fire extinguishing microcapsules according to claim 4, characterized in that, The emulsifier A and the emulsifier B are independently selected from one or more mixtures of sodium perfluorononenyloxybenzenesulfonate, Chemours FS64, FS30, FS61, FS60, FS3000, Merck FL2300, and 3M FC4430.

6. The preparation method of the multi-core fire-extinguishing microcapsule according to claim 4, wherein The water-soluble melamine prepolymer A and the water-soluble melamine prepolymer B are independently selected from one or more mixtures of Cytec 385, Shinli MF4750, and Shanghai Shuaike SK5710.

7. The preparation method of the multi-core fire extinguishing microcapsules according to claim 4, characterized in that, The acid solution A and the acid solution B are independently selected from one or more mixtures of citric acid, acrylic acid, acetic acid, dilute sulfuric acid, and dilute hydrochloric acid.

8. The preparation method of the multi-core fire extinguishing microcapsules according to claim 4, characterized in that, The mass ratio of the emulsifier B to the fire extinguishing agent B and the mass ratio of the emulsifier A to the fire extinguishing agent A are each independently 0.03 - 0.15:1; the mass ratio of the water-soluble melamine prepolymer A to the fire extinguishing agent A and the mass ratio of the water-soluble melamine prepolymer B to the fire extinguishing agent B are each independently 0.3 - 1:

1.

9. The preparation method of the multi-core fire-extinguishing microcapsule according to claim 4, wherein In step S101, adding acid solution B to adjust the pH value to 3 - 6, the temperature for the heating reaction is 40 - 60 °C, and the temperature for drying is 40 - 80 °C.

10. The preparation method of the multi-core fire-extinguishing microcapsules according to claim 4, wherein, In step S102, adding acid solution A to adjust the pH value to 3 - 6, the temperature for the heating reaction is 40 - 60 °C, and the temperature for drying is 40 - 80 °C.

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