A small-sized silicone gel composite arc-extinguishing material for fuses and a preparation method thereof

Abstract

A small fuse organic silicone glue composite arc extinguishing material and a preparation method thereof belong to the technical field of electronic components. The weight ratio of the composite arc extinguishing material is 60-90% of single-component room-temperature-cured organic silicone glue, 10-40% of magnesium hydroxide, aluminum hydroxide or silicon dioxide additives. The preparation method is as follows: the container is cleaned with alcohol, the two materials are weighed according to the set ratio, the weighed raw materials are sequentially added into the container, the flame-retardant material is initially dispersed into the organic silicone glue by manual uniform stirring through a slurry stirring scraper, the container is placed in a slurry vacuum degassing stirrer for stirring, the flame-retardant material is fully dispersed into the organic silicone glue, air in the organic silicone glue is removed, and then the organic silicone glue is moved to a syringe for standby. The problem that the electric arc cannot be extinguished in time in the existing fuse arc extinguishing technology, causing the fuse to be unable to be safely fused, is solved. The method can be widely applied to the arc extinguishing material technology of small wire fuses.

Description

Technical Field

[0001] This invention belongs to the field of electronic components technology, and more specifically to the field of fuse technology. In particular, it relates to an organic silicone composite arc-extinguishing material for small fuses and its preparation method. Background Technology

[0002] In electronic fuses, the process of arc generation and extinguishing when a fuse blows is as follows: The fuse melts under the influence of current, and an arc is generated under the influence of voltage. The arc burns the remaining molten material. If the arc cannot be extinguished at this point, it continues to burn the molten material until its energy is exhausted and the arc extinguishes. This process may cause the fuse body to explode and burn out, potentially affecting the circuit system and posing a safety hazard. Therefore, effectively suppressing the arc to ensure the safe blowing of the fuse is a crucial measure for the effective protection of the circuit.

[0003] Existing technologies use silicone rubber as the arc-extinguishing material in fuses, or a mixture of quartz sand and silicone rubber in a certain proportion. The latter, compared to the former, enhances the arc-cooling ability by adding quartz sand, resulting in a better arc-extinguishing effect. However, due to feasibility and operability considerations in the potting process, the quartz sand is not completely filled into every space of the silicone rubber; the main material of the arc-extinguishing material remains silicone rubber. Therefore, its arc-extinguishing performance relies solely on the silicone rubber forming a slit through potting, allowing the arc to move within the slit and compressing it, increasing the arc resistance and thus promoting arc extinction. Simultaneously, the arc's contact with the mixed quartz sand accelerates its cooling, thus extinguishing the arc. However, the arc heat absorption is limited, therefore its arc-extinguishing performance has certain limitations and cannot meet the safety fusing and breaking requirements of axial leaded fuses under 250VDC conditions, such as the φ2.4*7 axial leaded fuse.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the issue that in existing fuse arc extinguishing technologies, the electric arc cannot be extinguished in time, resulting in the inability to safely fuse.

[0006] The inventive concept of this invention is to enhance the flame-retardant properties of silicone rubber by dispersing flame-retardant materials into it, thereby improving the arc-extinguishing effect of silicone rubber. Utilizing the characteristics of silicone rubber and inorganic flame-retardant materials, a composite arc-extinguishing material is formed by adding a certain amount of aluminum hydroxide, silicon dioxide, or magnesium hydroxide to silicone rubber as a base material, which can then be used as the arc-extinguishing material for small wire fuses.

[0007] Therefore, this invention provides an organic silicone composite arc-extinguishing material for miniature fuses. The weight ratio of the composite arc-extinguishing material is as follows: 60%~90% single-component room temperature curing silicone, 10%~40% magnesium hydroxide, aluminum hydroxide or silica additives (flame retardants).

[0008] The method for preparing an organosilicon composite arc-extinguishing material for a miniature fuse includes the following preparation method: (1) Substrate preparation: Use single-component room temperature curing silicone.

[0009] (2) Additive preparation: Aluminum hydroxide, silicon dioxide or magnesium hydroxide are used as additives.

[0010] (3) Proportion: The base material is a single-component room temperature curing silicone, accounting for 60%~90%, and the additive is one of magnesium hydroxide, aluminum hydroxide and silicon dioxide, accounting for 10%~40%.

[0011] (4) Preparation: Clean the container used with the vacuum degassing mixer with alcohol. Weigh the two materials according to the set ratio using an electronic scale. Add the weighed raw materials to the container in sequence. First, manually stir at a uniform speed using a slurry stirring spatula to initially disperse the flame retardant material into the silicone. Then, place the container in the slurry vacuum degassing mixer and set the stirring parameters to a speed of 800 rpm to 900 rpm and a time of 60 s to 180 s to stir, ensuring the flame retardant material is fully dispersed into the silicone and removing air from the silicone. After stirring, transfer it to an injection syringe for use as a composite arc-extinguishing material for small wire fuses.

[0012] The arc-extinguishing mechanism of the composite arc-extinguishing material is as follows: When a small wire fuse melts, it generates a flying arc under the action of voltage. Especially under high voltage and high current, the arc energy is very large. At this time, an arc-extinguishing material is needed to extinguish the arc. In the composition of this invention, silicone can isolate air and form a slit, allowing the arc to move in the slit and compressing the arc, increasing the arc resistance, and thus promoting the arc extinguishing. At the same time, after the silicone is cross-linked and cured, it forms an elastic soft body that can buffer the pressure generated by the arc when it melts, thereby reducing the impact of the arc energy on the fuse tube. Aluminum hydroxide, silicon dioxide, and magnesium hydroxide absorb or directly absorb the latent heat released by the arc through their decomposition. At the same time, the magnesium oxide or aluminum oxide produced by the decomposition of aluminum hydroxide and magnesium hydroxide are also excellent refractory materials that can prevent the arc from continuing to burn the melt or silicone filling layer, thus playing a role in extinguishing the arc.

[0013] Therefore, the composite arc-extinguishing material can effectively suppress the electric arc generated when the filament fuse melts, thereby ensuring the safe melting and breaking of the fuse.

[0014] It can be widely used in arc-extinguishing material technology for small wire fuses. Detailed Implementation

[0015] The specific implementation method of the aforementioned silicone composite arc-extinguishing material for miniature fuses and its preparation method is as follows: The substrate is silicone, and the flame retardants are aluminum hydroxide, silicon dioxide, or magnesium hydroxide.

[0016] The three flame retardants were mixed with silicone rubber to prepare three composite arc-extinguishing materials: Composite Arc-Extinguishing Material 1 (aluminum hydroxide and silicone rubber composite arc-extinguishing material), Composite Arc-Extinguishing Material 2 (silica and silicone rubber composite arc-extinguishing material), and Composite Arc-Extinguishing Material 3 (magnesium hydroxide and silicone rubber composite arc-extinguishing material). These three composite arc-extinguishing materials were filled into the tubes of φ2.4*7 axial lead fuses (15A specification) and their electrical performance was tested. The results were compared with those of φ2.4*7 axial lead fuses (15A specification) filled only with silicone rubber and those without arc-extinguishing material. Five samples were tested for each voltage and corresponding current value. The test results are shown in Tables 1, 2, 3, 4, and 5.

[0017] Table 1. Breaking capacity of φ2.4*7 axial lead-type fuses (15A specification) filled with composite arc-extinguishing material 1.

[0018] Table 2 Breaking capacity of φ2.4*7 axial lead-type fuses (15A specification) filled with composite arc-extinguishing material 2

[0019] Table 3. Breaking capacity of 15A specification axial lead-type fuses with φ2.4*7 size filled with composite arc-extinguishing material 3.

[0020] Table 4 shows the breaking capacity of 15A axial lead fuses with a diameter of φ2.4*7 mm filled with silicone only.

[0021] Table 5. Breaking capacity of φ2.4*7 axial lead-type fuses (15A specification) without arc-extinguishing material specified.

[0022] The results of testing samples in three states show that: (1) The sample made of composite arc extinguishing material 1 can meet the short circuit current breaking test of 30A, 150A and 300A under the test voltage of 125VDC / 150VDC / 200VDC / 250VDC. The product appearance is intact after the test.

[0023] (2) The samples made of composite arc extinguishing material 2 can meet the short circuit current breaking test of 30A, 150A and 300A under 125VDC / 150VDC / 200VDC test voltage and the short circuit current breaking test of 30A and 150A under 250VDC test voltage. The products are in good condition after the test, but they cannot fully meet the short circuit current breaking test of 300A under 250VDC test voltage. Two products exploded after the test.

[0024] (3) The sample made of composite arc extinguishing material 3 can meet the short circuit current breaking test of 30A, 150A and 300A under the test voltage of 125VDC / 150VDC / 200VDC / 250VDC, and the product appearance is intact after the test.

[0025] (4) Samples filled with silicone can only meet the requirements of 30A and 50A breaking test under 125VDC test voltage. At 300A, one product tube exploded. When the test voltage is increased, the number of sample tubes exploded.

[0026] (5) The samples without arc-quenching material could not meet the above test conditions and all samples burst.

[0027] Test results show that adding aluminum hydroxide and magnesium hydroxide to silicone rubber effectively improves its arc-quenching performance. The formulated arc-quenching material can increase the rated voltage of a 15A axial-lead fuse (φ2.4*7) to 250VDC. This performance far exceeds that of similar 15A products on the market, which have a rated voltage of only 32VDC and a rated breaking capacity of only 300A@32VDC. While filled silica can also increase the voltage of a φ2.4*7 axial-lead fuse to 200VDC, its effect is slightly less than that of aluminum hydroxide and magnesium hydroxide.

[0028] The arc-extinguishing mechanism of composite arc-extinguishing materials is as follows: Silicone silicone's properties: The basic structural unit of silicone silicone is composed of silicon-oxygen linkages, with side chains linked to various organic groups through silicon atoms. Therefore, silicone products contain both "organic groups" and "inorganic structures," a unique composition and molecular structure that combines the properties of organic materials with the functions of inorganic materials. Silicone silicone products possess excellent electrical insulation properties. Their dielectric loss, voltage resistance, arc resistance, corona resistance, volume resistivity, and surface resistivity are among the highest of insulating materials. Therefore, they can be used as arc-extinguishing materials for small wire fuses. Encapsulating them within the fuse tube removes air from the tube, creating a slit that compresses the arc, increasing arc resistance and promoting arc extinguishing. Simultaneously, after cross-linking and curing, silicone silicone forms an elastic soft body that buffers the pressure generated by the arc during melting, reducing the impact of arc energy on the fuse tube. Furthermore, encapsulating with silicone silicone fixes the fuse wire, enhancing its resistance to mechanical impact and preventing oxidation.

[0029] Aluminum hydroxide is the most widely used and extensively applied inorganic flame retardant additive. Its working principle as a flame retardant is that upon heating, it decomposes, absorbing a large amount of heat and effectively reducing the surface temperature of the material. The water vapor produced during decomposition dilutes the concentration of surrounding flammable gases, inhibiting the combustion reaction. The aluminum oxide produced during decomposition forms a dense protective layer on the material surface, achieving flame retardancy by isolating oxygen and blocking heat transfer. It is particularly suitable for addition to silicone rubber and insulating rubber to enhance the flame retardant properties of the materials and improve their resistance to tracking, arcing, and flashover. Furthermore, considering the thermal decomposition process and products of aluminum hydroxide, it emits no harmful substances and can neutralize acidic and corrosive gases produced during combustion, making it an environmentally friendly green flame retardant that is safer than halogen-containing flame retardants.

[0030] Silica possesses nanoscale particle size, high specific surface area, excellent surface activity, and good chemical stability. Its structure is mostly amorphous or microcrystalline, exhibiting high heat resistance, weather resistance, and electrical insulation. It remains structurally stable within a temperature range of 200℃ to 1000℃, without decomposition or volatilization. Silica, after surface modification (such as treatment with silane coupling agents), can form good interfacial bonds with organic polymer matrices, significantly improving the mechanical properties, thermal stability, and flame retardancy of the materials. Adding silica to polymer materials can effectively improve their processing performance, rheological properties, and molding effects, while also enhancing their wear resistance, aging resistance, and corrosion resistance. In flame-retardant systems, silica can enhance the flame-retardant properties by forming a dense char layer or synergistically acting with flame retardants. Furthermore, its excellent insulating properties make it widely used in electronic packaging, cable insulation, and capacitor filling.

[0031] Magnesium hydroxide decomposes at 340℃ to produce magnesium oxide, which is insoluble in water, has high purity, small particle size, and excellent properties such as in-situ coating modification. It can be uniformly dispersed in rubber and plastic products such as PA, PP, ABS, and PVC. Magnesium hydroxide begins to decompose at 350℃, decomposes rapidly at 430℃, and completely decomposes at 490℃. When a fuse breaks, the melt temperature exceeds 490℃, causing the magnesium hydroxide to decompose thermally, releasing moisture and absorbing a large amount of latent heat. This lowers the actual flame temperature on the material surface, slows down the degradation of the polymer into lower molecular weight molecules, reduces the generation of flammable substances, and the released water vapor dilutes the oxygen concentration on the surface, making surface combustion more difficult. Simultaneously, the thermal decomposition of magnesium hydroxide forms magnesium oxide, which is also an excellent refractory material. It can prevent the electric arc from continuously burning the melt or the silicone filler layer. Therefore, using magnesium hydroxide as an arc-extinguishing material in small fuses can prevent the electric arc from burning the melt and the silicone filler layer. Meanwhile, considering the thermal decomposition process and products of magnesium hydroxide, it emits no harmful substances and can neutralize the acidic and corrosive gases produced during combustion, making it an environmentally friendly green flame retardant.

[0032] Finally, it should be noted that the above embodiments are merely examples for clear illustration. This invention includes, but is not limited to, the above embodiments, and it is neither necessary nor possible to exhaustively describe all possible implementations. Those skilled in the art can make other variations or modifications based on the above description. All implementation schemes that meet the requirements of this invention are within the protection scope of this invention.

Claims

1. An organic silicone composite arc-extinguishing material for miniature fuses, characterized in that, The weight ratio of the composite arc-quenching material is: 60%~90% single-component room temperature curing silicone, 10%~40% magnesium hydroxide, aluminum hydroxide or silica additives.

2. The silicone composite arc-extinguishing material for miniature fuses as described in claim 1, characterized in that: The fuse is a φ2.4*7 axial lead-type fuse, specification 15A.

3. The method for preparing an organosilicon composite arc-extinguishing material for a small fuse as described in claim 1 or 2, characterized in that, The preparation methods include the following: (1) Substrate preparation: Use single-component room temperature curing silicone; (2) Additive preparation: Aluminum hydroxide, silicon dioxide or magnesium hydroxide are used as additives; (3) Proportion: The base material is a single-component room temperature curing silicone rubber, accounting for 60%~90%, and the additive is one of magnesium hydroxide, aluminum hydroxide, and silicon dioxide, accounting for 10%~40%; (4) Preparation: Clean the container used with the vacuum degassing mixer with alcohol. Weigh the two materials according to the set ratio using an electronic scale. Add the weighed raw materials to the container in sequence. First, manually stir the slurry at a uniform speed with a slurry stirring scraper to initially disperse the flame retardant material into the silicone. Then, place the container in the slurry vacuum degassing mixer and set the stirring parameters to a speed of 800 rpm to 900 rpm and a time of 60 s to 180 s to stir it, so that the flame retardant material is fully dispersed into the silicone and the air in the silicone is removed. After stirring, transfer it to an injection syringe to be used as a composite arc extinguishing material for small wire fuses.

4. The preparation method of the silicone composite arc-extinguishing material for miniature fuses as described in claim 3, characterized in that: A 15A axial lead-type fuse with a diameter of φ2.4*7 filled with the composite arc-extinguishing material was tested under the following conditions: applied voltage of 125 VDC and applied currents of 30A, 150A and 300A respectively.

5. The preparation method of the silicone composite arc-extinguishing material for miniature fuses as described in claim 3, characterized in that: A 15A axial lead-type fuse with a diameter of φ2.4*7 filled with the composite arc-extinguishing material was tested under the following conditions: applied voltage of 150VDC and applied currents of 30A, 150A, and 300A.

6. The method for preparing an organosilicon composite arc-extinguishing material for a miniature fuse as described in claim 3, characterized in that: A 15A axial lead-type fuse with a diameter of φ2.4*7 filled with the composite arc-extinguishing material was tested under the following conditions: applied voltage of 200VDC and applied currents of 30A, 150A, and 300A respectively.

7. The preparation method of the silicone composite arc-extinguishing material for miniature fuses as described in claim 3, characterized in that: A 15A axial lead-type fuse with a diameter of φ2.4*7 filled with the composite arc-extinguishing material was tested under the following conditions: applied voltage of 250VDC and applied currents of 30A, 150A, and 300A respectively.

Images