Silica / melamine composite arc extinguishing material and its preparation method

Abstract

The present invention discloses a silica / melamine composite arc extinguishing material and a preparation method thereof. The preparation method includes the steps of: (1) putting SiO2, a solvent and melamine into a reaction vessel to form a mixed system; (2) performing stirring or ultrasonic treatment after step (1); (3) removing the solvent in the mixed system to obtain the silica / melamine composite arc extinguishing material. The preparation method of the present invention enables the melamine molecules to be firmly adsorbed and uniformly distributed on the surface of SiO2, so that the prepared silica / melamine composite arc extinguishing material exhibits uniformity in properties and achieves excellent arc extinguishing performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of arc extinguishing materials, and particularly relates to a silica / melamine composite arc extinguishing material and a preparation method thereof. Background Art

[0002] A fuse is an electrical appliance that melts the fuse wire by the heat generated by itself to disconnect the circuit when the current exceeds the specified value. A fuse is a current protector that melts the fuse wire by the heat generated by itself after the current exceeds the specified value for a period of time, thereby disconnecting the circuit. Fuses are widely used in high and low voltage power distribution systems, control systems, and electrical equipment. As short-circuit and over-current protectors, they are one of the most commonly used protection devices.

[0003] Quartz sand (SiO2) and melamine are common arc suppressing and arc extinguishing materials and are widely used in the field of fuses. SiO2 mainly cools the arc physically, separates the arc, and adsorbs metal vapor, while melamine decomposes at high temperatures to generate a large amount of gas to disperse the arc, thereby achieving the purpose of arc extinction. Combining quartz sand (SiO2) and melamine and making them work synergistically often can achieve better arc extinguishing effects. However, the current usage method is still mainly physical and mechanical mixing. Due to the large differences in chemical structure, physical and chemical properties, and particle size between SiO2 and melamine, it is often difficult to mix them evenly, and the uniformity of the prepared arc extinguishing material is poor and the performance is unstable. At the same time, since solid melamine usually exists in the form of micron-sized (or even larger-sized) particles, it has a small specific surface area and low reaction activity, and it is difficult to generate sufficient arc extinguishing gas instantaneously at high temperatures, thus affecting the arc extinguishing effect; while nano-sized melamine particles have defects such as high preparation cost, easy agglomeration, and difficulty in uniformly mixing with other solid particles.

[0004] Therefore, there is an urgent need to develop a silica / melamine composite arc extinguishing material and a preparation method thereof to solve problems such as poor mixing uniformity of SiO2 and melamine in existing arc extinguishing materials and low material utilization rate. Summary of the Invention

[0005] In view of the above technical problems, the purpose of the present invention is to provide a silica / melamine composite arc extinguishing material and a preparation method thereof. The preparation method of the present invention enables melamine molecules to be firmly adsorbed and evenly distributed on the surface of SiO2, so that the prepared silica / melamine composite arc extinguishing material exhibits uniformity in properties and achieves excellent arc extinguishing performance.

[0006] To achieve the above purpose, the first aspect of the present invention provides a preparation method of a silica / melamine composite arc extinguishing material, including the following steps:

[0007] (1) Put SiO2, a solvent, and melamine into a reaction vessel to form a mixed system;

[0008] (2) After step (1), perform stirring or ultrasonic treatment;

[0009] (3) Remove the solvent from the mixed system to obtain a silica / melamine composite arc extinguishing material.

[0010] Compared with the prior art, in the present invention, SiO2, a solvent, and melamine form a mixed system. Melamine is dissolved by the solvent to form independent and free melamine molecules. The surface of SiO2 nanoparticles contains hydroxyl (-OH) functional groups. When melamine molecules come into contact with the surface of SiO2 particles, the amino group (-NH2) in the melamine molecules forms a hydrogen bond interaction with the hydroxyl groups on the surface of SiO2, enabling the melamine molecules to be firmly adsorbed on the surface of SiO2 particles. At the same time, under the action of stirring or ultrasonic treatment, the concentration of melamine molecules is uniform throughout the solution, which enables each SiO2 particle to contact melamine molecules with a relatively consistent concentration. Therefore, uniform adsorption of melamine molecules on the surface of all SiO2 particles can be achieved, which significantly increases the specific surface area of melamine, effectively improves its reaction activity, and further increases the gas generation rate per unit time during the high-temperature decomposition of the silica / melamine composite arc extinguishing material. Therefore, the preparation method of the present invention enables the melamine molecules to be firmly adsorbed and uniformly distributed on the surface of SiO2, so that the prepared silica / melamine composite arc extinguishing material exhibits uniformity in properties and achieves excellent arc extinguishing performance. In addition, the raw materials used in the preparation method of the present invention are inexpensive, and the preparation process is simple, which is particularly suitable for large-scale preparation of silica / melamine composite arc extinguishing materials.

[0011] Further, the mass ratio of SiO2 to melamine in the present invention is 1 to 20:1. Specifically, the mass ratio of SiO2 to melamine can be, but is not limited to, 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 8:1, 10:1, 11:1, 12:1, 15:1, 18:1, 20:1. Specifically, the present invention can control the adsorption amount of melamine on the surface of SiO2 particles by controlling the ratio of SiO2 to melamine, thereby forming a melamine surface layer with a controllable thickness to meet different actual requirements.

[0012] Further, the mass ratio of SiO2 to melamine in the present invention is preferably 1 to 5:1.

[0013] Further, the SiO2 in the present invention is column chromatography silica gel, and the particle size of the column chromatography silica gel is 40 to 300 μm, and the pore size is The surface of SiO2 in commercial column chromatography silica gel contains a large number of -OH groups, which helps SiO2 form hydrogen bond interactions with melamine molecules. Preferably, the particle size of the column chromatography silica gel is 40 - 45 μm, and the pore size is

[0014] Furthermore, the solvent of the present invention includes at least one of methanol, water, ethanol, ethylene glycol, glycerol, pyridine, formaldehyde, and acetic acid. It should be noted that the solvent of the present invention is not limited thereto, and other solvents that can dissolve melamine are also within the protection scope of the present invention. For example, the solvent can also be dimethyl sulfoxide.

[0015] Furthermore, in step (2) of the present invention, the temperature of stirring or ultrasonic treatment is from room temperature to 100 °C. Room temperature generally refers to 10 - 30 °C. Specifically, the temperature can be, but is not limited to, 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 75 °C, 85 °C, 100 °C. Preferably, the temperature of stirring or ultrasonic treatment in step (2) is from room temperature to 80 °C.

[0016] Furthermore, in step (2) of the present invention, the time of stirring or ultrasonic treatment is 2 - 48 h. The time can be specifically, but is not limited to, 2 h, 5 h, 10 h, 18 h, 24 h, 28 h, 32 h, 38 h, 42 h, 45 h, 47 h, 48 h. Preferably, the time is 2 - 36 h; more preferably, the time is 2 - 24 h. More specifically, the ultrasonic power of ultrasonic treatment is 800 - 1200 W, and the ultrasonic frequency is 60 - 100 kHz;

[0017] Furthermore, in step (3) of the present invention, it includes removing the solvent in the mixed system by heating evaporation, rotary evaporation, or drying after filtration. Specifically, the drying treatment can include natural air drying or low-temperature drying.

[0018] Furthermore, step (1) of the present invention includes adding SiO2 and the solvent into a flask and adding melamine into a Soxhlet extractor connected to the flask to form a mixed system. That is, the reaction vessel includes a flask and a Soxhlet extractor connected to the flask. Such a setting can ensure that melamine is slowly and evenly dissolved in the solvent, which is beneficial for the firm adsorption and uniform distribution of melamine molecules on the surface of SiO2. Of course, for a more convenient preparation of the silica / melamine composite arc extinguishing material, the reaction vessel can be a flask, a beaker. Of course, other containers that can be used for stirring can also be used. Specifically, for example, SiO2, the solvent, and melamine can be directly mixed in a beaker or a flask to form a mixed system.

[0019] Correspondingly, the second aspect of the present invention provides a silica / melamine composite arc extinguishing material prepared by using the preparation method of the silica / melamine composite arc extinguishing material mentioned above.

[0020] Compared with the prior art, in the silica / melamine composite arc extinguishing material of the present invention, melamine molecules are firmly adsorbed and uniformly distributed on the surface of SiO2. The silica / melamine composite arc extinguishing material exhibits homogeneity in properties, combining both physical and chemical arc extinguishing performances, achieving excellent arc extinguishing performance. When an arc occurs, SiO2 can absorb the arc energy and separate the arc, while melamine decomposes under the action of the arc, generating a large amount of arc extinguishing gas, causing a sharp increase in the internal pressure of the device, thereby accelerating the arc extinction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of the silica / melamine composite arc extinguishing material of the present invention.

[0022] Figure 2 It is a schematic diagram of the formation of hydrogen bonds between melamine and SiO2 of the present invention.

[0023] Figure 3 It is a schematic structural diagram of an embodiment of the reaction vessel of the present invention.

[0024] Figure 4 It is a fusing waveform diagram of a fuse containing the silica / melamine composite arc extinguishing material of Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To better illustrate the purpose, technical solution and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments and drawings. It should be noted that the following embodiments are further explanatory descriptions of the present invention and should not be regarded as limitations on the present invention.

[0026] In order to overcome the problems such as the difficult uniform distribution of each component brought by the physical and mechanical mixing methods in the prior art, please refer to Figure 1 , the present invention provides a silica / melamine composite arc extinguishing material 100, and the silica / melamine composite arc extinguishing material 100 includes a SiO2 core 11 and a melamine surface layer 12.

[0027] Further, please refer to Figure 2 , the present invention provides a silica / melamine composite arc extinguishing material, which is prepared by surface modification of SiO2 with melamine. Specifically, hydrogen bond interaction is formed between the hydroxyl groups (-OH) on the surface of SiO2 and the amino groups (-NH2) or N atoms in melamine molecules, so that melamine molecules are firmly adsorbed on the surface of SiO2.

[0028] Further, in order to more facilitate the firm adsorption and uniform distribution of melamine molecules on the surface of SiO2, the present invention provides a method as Figure 3The reaction vessel 200 shown includes a flask 21 and a Soxhlet extractor 22 communicating with the flask 21. Specifically, SiO2 and a solvent can be added to the flask 21, and melamine 23 can be added to the Soxhlet extractor 22. Then, a condenser 24 is connected to form a mixed system.

[0029] To more specifically illustrate the purpose, technical solution, and beneficial effects of the present invention, the following will be further described in conjunction with specific embodiments.

[0030] Example 1

[0031] This example provides a method for preparing a silica / melamine composite arc extinguishing material, including the following steps:

[0032] (1) Add 100 g of SiO2 (column chromatography silica gel, particle size 40 - 45 μm, pore size ) and 500 ml of methanol to a 1 L single-neck round-bottom flask, place a magnetic stir bar, connect a Soxhlet extractor, and place 20 g of melamine in the filter paper cartridge inside the Soxhlet extractor. Then, connect a condenser to form a mixed system;

[0033] (2) After step (1), stir at a temperature of 70 °C for 24 h;

[0034] (3) Filter the mixture in the flask with filter paper, then wash the solid product on the filter paper with ether (3 × 30 ml), and air-dry the solid product on the filter paper to obtain the silica / melamine composite arc extinguishing material.

[0035] Example 2

[0036] This example provides a method for preparing a silica / melamine composite arc extinguishing material, which is basically the same as Example 1, except that the mass of SiO2 is 80 g.

[0037] Example 3

[0038] This example provides a method for preparing a silica / melamine composite arc extinguishing material, which is basically the same as Example 1, except that the mass of SiO2 is 60 g.

[0039] Example 4

[0040] This example provides a method for preparing a silica / melamine composite arc extinguishing material, which is basically the same as Example 1, except that the mass of SiO2 is 40 g.

[0041] Example 5

[0042] This example provides a method for preparing a silica / melamine composite arc extinguishing material, which is basically the same as Example 1, except that the mass of SiO2 is 20 g.

[0043] Example 6

[0044] This example provides a method for preparing a silica / melamine composite arc extinguishing material, comprising the following steps:

[0045] (1) Add 2.5 g of melamine and 1 L of water into a flask, then add 50 g of SiO2 (particle size 40 - 45 μm, pore size ) into the flask, and place a magnetic stir bar.

[0046] (2) After step (1), stir at room temperature for 24 h.

[0047] (3) Filter the mixture in the flask with filter paper, then wash the solid on the filter paper with ethanol and ether in sequence, and air-dry the solid on the filter paper to obtain the silica / melamine composite arc extinguishing material.

[0048] Example 7

[0049] This example provides a method for preparing a silica / melamine composite arc extinguishing material, comprising the following steps:

[0050] (1) Place 20 g of melamine, 100 g of SiO2 (particle size 40 - 45 μm, pore size ) and 300 ml of methanol into a 500 ml single-necked round-bottom flask.

[0051] (2) After step (1), perform ultrasonic treatment at room temperature for 2 h, where the ultrasonic power is 1200 W and the ultrasonic frequency is 80 kHz.

[0052] (3) Use a rotary evaporator to evaporate the methanol in the flask to obtain the silica / melamine composite arc extinguishing material.

[0053] Comparative Example 1

[0054] This comparative example provides an arc extinguishing material, which is SiO2 solid particles (column chromatography silica gel, particle size 40 - 45 μm, pore size ).

[0055] Comparative Example 2

[0056] This comparative example provides an arc extinguishing material, which is melamine particles with a particle size less than 45 μm.

[0057] Comparative Example 3

[0058] This comparative example provides a silica / melamine composite arc extinguishing material, including the following steps:

[0059] Mix 100 g of SiO2 (column chromatography silica gel, particle size 40 - 45 μm, pore size ) and 20 g of melamine particles (particle size less than 45 μm) by stirring to obtain the silica / melamine composite arc extinguishing material.

[0060] Comparative Example 4

[0061] This comparative example provides a silica / melamine composite arc extinguishing material, which is basically the same as Comparative Example 3, except that: the mass of SiO2 is 80 g.

[0062] Comparative Example 5

[0063] This comparative example provides a silica / melamine composite arc extinguishing material, which is basically the same as Comparative Example 3, except that: the mass of SiO2 is 60 g.

[0064] Comparative Example 6

[0065] This comparative example provides a silica / melamine composite arc extinguishing material, which is basically the same as Comparative Example 3, except that: the mass of SiO2 is 40 g.

[0066] Comparative Example 7

[0067] This comparative example provides a silica / melamine composite arc extinguishing material, which is basically the same as Comparative Example 3, except that: the mass of SiO2 is 20 g.

[0068] Comparative Example 8

[0069] This comparative example provides a silica / melamine composite arc extinguishing material, including the following steps:

[0070] Spray 20 g of melamine (particle size less than 45 μm) onto the surface of 100 g of silica (column chromatography silica gel, particle size 40 - 45 μm, pore size ) by using electrostatic spraying technology to obtain the silica / melamine composite arc extinguishing material.

[0071] The arc extinguishing materials prepared in Examples 1-7 and Comparative Examples 1-8 were poured into fuses. The rated voltage of the fuses was 500 VDC and the rated current was 100 A. The performance of the fuses was tested in accordance with Standards GB / T31465-2015 and GB / T31465-2017. The test instruments were a short-circuit test platform (DL10KV-100), a megohmmeter (AR3127), a DC programmable power supply (IT6932A), and a 6 1 / 2-digit multimeter (34401A). The test conditions were an experimental voltage of 500 VDC, an expected test current of 50 kA, a time constant of 3 ± 0.5 ms, an ambient temperature of 20.7 °C, and a humidity of 46% RH. The test results are shown in Table 1. The fuse melting waveform diagram containing the silica / melamine composite arc extinguishing material of Example 1 is as Figure 4 shown.

[0072] Table 1 Test results of the arc extinguishing performance of the arc extinguishing materials

[0073]

[0074]

[0075] As can be seen from Table 1 and Figure 4 it can be seen that compared with Comparative Examples 1-8, the silica / melamine composite arc extinguishing materials of Examples 1-7 can achieve excellent arc extinguishing performance. This is because in the present invention, SiO2, a solvent, and melamine form a mixed system, and melamine is dissolved by the solvent to form independent and free melamine molecules. The surface of the SiO2 nanoparticles contains hydroxyl (-OH) functional groups. When the melamine molecules contact the surface of the SiO2 particles, the amino groups (-NH2) in the melamine molecules form hydrogen bond interactions with the hydroxyl groups on the surface of SiO2, so that the melamine molecules are firmly adsorbed on the surface of the SiO2 particles. At the same time, under the action of stirring or ultrasonic treatment, the concentration of melamine molecules is uniform everywhere in the solution, which enables each SiO2 particle to contact melamine molecules with a relatively consistent concentration. Therefore, uniform adsorption of melamine molecules on the surface of all SiO2 particles can be achieved, which significantly increases the specific surface area of melamine, effectively improves its reaction activity, and increases the gas generation rate per unit time when the silica / melamine composite arc extinguishing material decomposes at high temperature. Therefore, the preparation method of the present invention enables the melamine molecules to be firmly adsorbed and uniformly distributed on the surface of SiO2, so that the prepared silica / melamine composite arc extinguishing material exhibits uniformity in properties and achieves excellent arc extinguishing performance.

[0076] Comparing Example 1 with Comparative Examples 1 to 3, it can be seen that the silica / melamine composite arc extinguishing material provided by the present invention can effectively extinguish arcs, and its arc extinguishing effect is better than that of using SiO2 or melamine alone, as well as the arc extinguishing effect of the simple mechanical mixture of SiO2 and melamine. This also indicates that the preparation method of the present invention can solve the problems such as the difficult uniform distribution of each component caused by the physical and mechanical mixing methods in the prior art.

[0077] Comparing Example 1 and Comparative Example 8, it can be seen that the silica / melamine composite arc extinguishing material provided by the present invention can effectively extinguish arcs, and its arc extinguishing effect is better than that of spraying melamine on the surface of silica. This is because during the spraying process, the solid particles inside the silica will be blocked by the solid particles on the periphery, easily forming spraying dead corners, making it impossible or less for the internal solid particles to be splashed by the powder; at the same time, affected by the spraying angle, it is also difficult for melamine to be evenly distributed on the silica particles; more importantly, this spraying method cannot or is difficult to make melamine form a hydrogen bond adsorption effect on the surface of silica. Since the formation of hydrogen bonds usually requires a solution, and the material forms a chemical interaction with the surface groups of the matrix at the molecular level, that is, directly spraying the melamine powder on the surface of silica, this binding method is mainly physical adsorption, and it is difficult to achieve the firm adsorption and uniform distribution of melamine on the surface of the matrix.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, it is not limited to only the embodiments listed. Those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A preparation method of a silica / melamine composite arc extinguishing material, characterized in that, It includes the following steps: (1) Put SiO2, a solvent and melamine into a reaction vessel to form a mixed system; (2) Carry out stirring or ultrasonic treatment after step (1); (3) Remove the solvent from the mixed system to obtain a silica / melamine composite arc extinguishing material, and the silica / melamine composite arc extinguishing material includes a SiO2 core and a melamine surface layer; The solvent includes at least one of methanol, water, ethylene glycol, glycerol, pyridine, formaldehyde and acetic acid; The SiO2 is column chromatography silica gel, and the particle size of the column chromatography silica gel is 40 to 300 μm, and the pore size is 2. The preparation method of the silica / melamine composite arc extinguishing material according to claim 1, characterized in that, The mass ratio of the SiO2 to the melamine is 1-20:

1.

3. The preparation method of the silica / melamine composite arc extinguishing material according to claim 1, characterized in that, The mass ratio of the SiO2 to the melamine is 1-5:

1.

4. The preparation method of the silica / melamine composite arc extinguishing material according to claim 1, characterized in that, In step (2), the temperature of the stirring or the ultrasonic treatment is room temperature to 100 °C.

5. The preparation method of the silica / melamine composite arc extinguishing material according to claim 1, characterized in that, In step (2), the time of the stirring or the ultrasonic treatment is 2-48 h.

6. The preparation method of the silica / melamine composite arc extinguishing material according to claim 1, characterized in that, Step (3) includes using heating evaporation, rotary evaporation or drying after filtration to remove the solvent from the mixed system.

7. The preparation method of the silica / melamine composite arc extinguishing material according to claim 1, wherein, Step (1) includes adding the SiO2 and the solvent into a flask and adding the melamine into a Soxhlet extractor connected to the flask to form a mixed system.

8. A silica / melamine composite arc extinguishing material, characterized in that, It is prepared by using the preparation method of the silica / melamine composite arc extinguishing material according to any one of claims 1-7.

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