A circuit board explosion-proof adhesive structure, an explosion-proof circuit board and an explosion-proof electronic device

Abstract

The application discloses a circuit board explosion-proof glue structure, which comprises a bottom glue layer, a surface glue layer and a reinforcing structure. The bottom glue layer is coated and solidified on the surface of the circuit board. The surface glue layer is coated and solidified on the side, away from the circuit board, of the bottom glue layer. The reinforcing structure is embedded in the surface glue layer, so that the surface glue layer forms a continuous body which can be integrally peeled off. The temperature resistance of the bottom glue layer is lower than that of the surface glue layer and the reinforcing structure. The application sets a layer of low-temperature-resistant glue between the circuit board and silica gel or electronic glue, so that the surface glue layer can be easily removed in pieces. The reinforcing structure is arranged in the surface glue layer, so that the surface glue layer is integrated. The glue is attached to the circuit board, and the glue can be easily removed, so that the difficulty of maintenance is reduced, the balance between high adhesion and maintainability of the explosion-proof glue is achieved, and the damage of physical glue scraping to the PCBA is avoided.

Description

Technical Field

[0001] This application relates to the technical field of circuit board post-processing, specifically to a circuit board explosion-proof adhesive structure, an explosion-proof circuit board, and explosion-proof electronic equipment. Background Technology

[0002] Explosion-proof mobile phones are communication devices certified by national explosion-proof testing institutions, specifically designed for flammable, explosive, and dusty environments in industries such as petroleum, chemical, pharmaceutical, and natural gas. Their core principle employs intrinsically safe design, using technologies such as optimized circuit structure, encapsulated electronic components, and anti-static material casings to suppress effective ignition sources caused by electrical sparks, short circuits, or mechanical damage. For example, battery protection boards require the application of silicone or electronic adhesive to protect circuit board components and prevent potential sparks during use.

[0003] In the existing technology, silicone or electronic adhesive is applied directly to the surface of the circuit board components and cured onto the circuit board surface. After curing, the adhesive needs to have adhesion to the board and cannot detach from the circuit board in order to cope with accidental collisions with electronic devices.

[0004] However, when repairing equipment, the cured adhesive has strong adhesion to the circuit board and needs to be physically scraped off, which can easily damage components and pads. The scraping process may cause micro-cracks in the circuit board and displacement of components, increasing the failure rate of the equipment after repair. In addition, manual scraping is time-consuming and increases costs. Utility Model Content

[0005] This application provides a circuit board explosion-proof adhesive structure that ensures the adhesive adheres well to the circuit board while facilitating removal to reduce maintenance difficulty.

[0006] According to one aspect of this application, one embodiment provides a circuit board explosion-proof adhesive structure, comprising:

[0007] The bottom adhesive layer is coated and cured onto the circuit board surface;

[0008] A surface adhesive layer is applied to cover and cure the bottom adhesive layer on the side away from the circuit board.

[0009] A reinforced structure is embedded in the surface adhesive layer so that the surface adhesive layer forms a continuous body that can be peeled off as a whole;

[0010] The temperature resistance of the bottom adhesive layer is lower than that of the surface adhesive layer and the reinforcing structure.

[0011] In another embodiment, the temperature difference between the melting points of the bottom adhesive layer and the top adhesive layer is not less than 60°C.

[0012] In another embodiment, the bottom adhesive layer is a polyurethane adhesive, the top adhesive layer is a silicone or epoxy resin adhesive, and the thickness of the top adhesive layer is greater than the thickness of the bottom adhesive layer.

[0013] In another embodiment, the surface adhesive layer does not extend beyond the coverage area of ​​the underlying adhesive layer.

[0014] In another embodiment, the reinforcing structure includes a heat-resistant mesh that is fully embedded within the uncured surface adhesive layer.

[0015] In another embodiment, the reinforcing structure includes a plurality of heat-resistant fibers dispersed within and mixed with the surface adhesive layer.

[0016] In another embodiment, the reinforcing structure does not extend beyond the coverage area of ​​the surface adhesive layer.

[0017] According to one aspect of this application, one embodiment provides an explosion-proof circuit board, including a PCBA and the above-described explosion-proof adhesive structure, wherein the bottom adhesive layer of the explosion-proof adhesive structure is coated on the surface of the PCBA.

[0018] In another embodiment, the PCBA surface is configured with a plurality of electronic components, and the bottom adhesive layer covers the solder feet of the electronic components and the pads of the PCBA.

[0019] According to one aspect of this application, one embodiment provides an explosion-proof electronic device, including the explosion-proof circuit board described above.

[0020] Based on the circuit board explosion-proof adhesive structure and explosion-proof circuit board of the above embodiments, when repairing the corresponding explosion-proof electronic equipment, it is only necessary to heat the entire circuit board to between the temperature resistance of the bottom adhesive layer and the temperature resistance of the surface adhesive layer. The adhesive at the bottom will then melt. Due to the reinforcing structure inside the surface adhesive layer, the surface adhesive layer can be made as a whole, thus making it easy to remove the surface adhesive layer in pieces. The added bottom adhesive layer has an additional fixing and moisture-proof effect on the protected components. At the same time, it isolates the surface adhesive layer from the circuit board surface, reducing the impact of the surface adhesive layer on the circuit board. While ensuring the adhesion of the adhesive to the circuit board, it is easy to remove the adhesive to reduce the difficulty of repair, achieving a balance between the high adhesion and maintainability of the explosion-proof adhesive, and avoiding damage to the PCBA caused by physical scraping of the adhesive. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the explosion-proof circuit board in one embodiment;

[0022] Figure 2 This is an explosion-proof circuit board diagram from one embodiment;

[0023] Figure 3This is an overall side view of the explosion-proof circuit board in one embodiment;

[0024] Figure 4 This is a schematic diagram of the overall structure of the explosion-proof circuit board in another embodiment.

[0025] Figure label:

[0026] 1. PCBA; 2. Electronic components; 3. Underlying adhesive layer; 4. Top adhesive layer; 5. Reinforcing structure; 51. Heat-resistant mesh; 52. Heat-resistant fiber. Detailed Implementation

[0027] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0028] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments, and the operational steps involved in each embodiment can also be rearranged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the specification and drawings are only for clearly describing a particular embodiment and do not imply that they represent the necessary components and / or order.

[0029] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0030] Printed circuit boards, also known as printed circuit boards or printed circuit boards, are important electronic components. They serve as the support for electronic components and provide the wiring connections between them. A bare PCB board undergoes surface mount technology (SMT) assembly, DIP (Dual In-line Package) assembly, or the final product is referred to as PCBA1.

[0031] Explosion-proof mobile phones are communication devices certified by national explosion-proof testing institutions, specifically designed for flammable, explosive, and dusty environments in industries such as petroleum, chemical, pharmaceutical, and natural gas. Their core principle employs intrinsically safe design, using technologies such as optimized circuit structure, encapsulated electronic components, and anti-static material casings to suppress effective ignition sources caused by electrical sparks, short circuits, or mechanical damage. For example, battery protection boards require the application of silicone or electronic adhesive to protect circuit board components and prevent potential sparks during use.

[0032] In the existing technology, silicone or electronic adhesive is applied directly to the surface of the circuit board components and cured onto the circuit board surface. After curing, the adhesive needs to have adhesion to the board and cannot detach from the circuit board in order to cope with accidental collisions with electronic devices.

[0033] However, when repairing equipment, the cured adhesive has strong adhesion to the circuit board and needs to be physically scraped off, which can easily damage components and pads. The scraping process may cause micro-cracks in the circuit board and displacement of components, increasing the failure rate of the equipment after repair. In addition, manual scraping is time-consuming and increases costs.

[0034] This application provides a circuit board explosion-proof adhesive structure. By placing a layer of low-temperature resistant adhesive between the circuit board and silicone or electronic adhesive, the adhesive is guaranteed to adhere to the circuit board while facilitating removal to reduce maintenance difficulty. This achieves a balance between high adhesion and maintainability of the explosion-proof adhesive and avoids damage to PCBA1 caused by physical scraping of the adhesive.

[0035] Example 1:

[0036] Please refer to Figure 1 and Figure 2 An explosion-proof adhesive structure for a circuit board includes: a bottom adhesive layer 3, coated and cured on the surface of the circuit board; a top adhesive layer 4, covering and cured on the side of the bottom adhesive layer 3 away from the circuit board; and a reinforcing structure 5, embedded in the top adhesive layer 4 so that the top adhesive layer 4 forms a continuous body that can be peeled off as a whole; wherein the temperature resistance of the bottom adhesive layer 3 is lower than that of the top adhesive layer 4 and the reinforcing structure 5.

[0037] Furthermore, the bottom adhesive layer 3 and the top adhesive layer 4 need to have a certain melting point temperature difference so that they can adapt to the fluctuations of the actual heating temperature during maintenance heating, and will not affect the top adhesive layer 4 due to the small temperature difference, thus ensuring the integrity and solid state of the top adhesive layer 4.

[0038] In this embodiment, the melting point temperature difference between the bottom adhesive layer 3 and the top adhesive layer 4 is not less than 60°C to ensure a clear operating temperature window during maintenance heating; the thickness of the top adhesive layer 4 is greater than the thickness of the bottom adhesive layer 3; the top adhesive layer 4 does not exceed the coverage area of ​​the bottom adhesive layer 3 to ensure that the peeling operation starts from the edge and is easy to perform.

[0039] For details, please refer to Figure 2 and Figure 3 The bottom adhesive layer 3 is coated and cured onto the circuit board surface. Its key characteristic is its relatively low temperature resistance; preferably, but not limited to, materials with a temperature resistance not exceeding 120°C, such as polyurethane adhesive (PU adhesive). The bottom adhesive layer 3 is applied by brushing or spraying, and its thickness is relatively thin, typically between 0.05mm and 0.2mm. Its main functions are, on the one hand, to provide initial moisture protection, insulation, and fixation protection for the electronic components 2 on the circuit board at room temperature; on the other hand, its low temperature resistance is crucial for achieving interface separation during subsequent repairs.

[0040] Please refer to Figure 2 and Figure 3 The surface adhesive layer 4 covers the bottom adhesive layer 3. This adhesive layer uses a high-strength, high-adhesion, and high-temperature-resistant heat-dissipating or protective adhesive, such as silicone or epoxy resin, with a temperature resistance of not less than 180℃, preferably above 200℃. It is relatively thick, typically between 0.5mm and 2mm, and its main functions are explosion-proof, heat dissipation, and mechanical impact protection.

[0041] Furthermore, in this embodiment, please refer to Figure 2 and Figure 3 The reinforcing structure 5 includes a heat-resistant mesh 51, which is completely embedded in the uncured surface adhesive layer 4. The heat-resistant mesh 51 can be made of fiberglass mesh, metal wire mesh, etc.

[0042] Specifically, the reinforcing structure 5 itself needs to have high temperature resistance (≥200℃), and its core functions are "toughening" and "interlocking", connecting the entire surface adhesive layer 4 into a strong and continuous whole with uniform mechanical properties, thereby giving it the characteristic of "being peelable as a whole".

[0043] In this embodiment, please refer to Figure 2 and Figure 3 The reinforcing structure 5 does not exceed the coverage area of ​​the surface adhesive layer 4, further enhancing the overall integrity between the two.

[0044] Furthermore, in this embodiment, after the bottom adhesive layer 3 dries, a top adhesive layer 4 is applied on top of the existing low-melting-point bottom adhesive layer 3. Before the top adhesive layer dries, a reinforcing structure 5 is pressed into the top adhesive layer to connect the top adhesive layer 4 into a whole.

[0045] In this embodiment, for the circuit board with the electronic components 2 already soldered, a polyurethane adhesive with a temperature resistance of approximately 120°C is selected as the base adhesive material. It is evenly sprayed onto the corresponding surface of the circuit board using a spraying / brushing device, ensuring that the adhesive penetrates and covers all the solder feet and surrounding pads of the components. Then, it is cured using appropriate equipment or naturally to form a thin, dense base adhesive layer 3.

[0046] Subsequently, the circuit board is assembled, and a high thermal conductivity silicone rubber with a temperature resistance greater than 200℃ is selected as the surface adhesive material. The silicone rubber is applied to the surface of the bottom adhesive layer 3 using a dispensing machine. While the silicone rubber is still in a leveled state before it has cured, a heat-resistant mesh 51 with a temperature resistance greater than 200℃ is pressed flat into the silicone rubber, ensuring that the mesh is completely encapsulated by the silicone rubber, and that there is a certain distance between the edge of the heat-resistant mesh 51 and the outer surface of the finally cured surface layer. Finally, the silicone rubber is heated to cure, thereby forming a robust surface adhesive layer 41 with a thickness greater than the bottom adhesive layer 3 and containing the heat-resistant mesh 51. This forms a complete mesh-reinforced explosion-proof adhesive structure.

[0047] Furthermore, during repair, the circuit board only needs to be heated to a temperature between the bottom adhesive layer 3 and the surface adhesive layer 4. For example, the repair technician can set the hot air gun temperature to 150°C and heat the area to be repaired evenly. At this time, the bottom adhesive layer 3 softens and loses its stickiness, becoming molten, while the surface silicone and its internal heat-resistant mesh 51 remain solid due to their high temperature resistance. Because the reinforcing structure 5 inside the surface adhesive layer 4 allows it to remain intact, the surface adhesive layer 4 can be easily removed piece by piece from the edges using tools such as tweezers, allowing the entire surface protective structure to be easily peeled off. Any residual surface adhesive layer 4 on the circuit board will be naturally decomposed and removed by the rosin in the solder during subsequent 240°C soldering operations, without affecting the soldering quality.

[0048] In this embodiment, the bottom adhesive provides moisture protection and curing properties to the circuit board at room temperature, improving the overall quality of the circuit board. This reduces the difficulty of repair and minimizes damage to the electronic components 2 and the board surface caused by scraping the adhesive during repair. Furthermore, this embodiment uses industry-standard adhesives and tools, making it convenient and easy to implement. The added low-temperature resistant bottom adhesive layer 3 is highly stable at room temperature, providing additional fixation and moisture protection for the protected electronic components 2. Simultaneously, the bottom adhesive layer 3 isolates the surface adhesive layer 4 from the circuit board surface, preventing the difficult-to-remove and melted surface adhesive layer 4 from penetrating into the gap between the component pads and the circuit board. This achieves a balance between the high adhesion and maintainability of the explosion-proof adhesive, avoiding damage to the PCBA1 from physical scraping and improving disassembly efficiency.

[0049] Example 2:

[0050] The difference between this embodiment and Embodiment 1 is that, in this embodiment, please refer to... Figure 4 The reinforcing structure 5 includes several heat-resistant fibers 52, which are dispersed within the surface adhesive layer 4 and mixed with it; and the reinforcing structure 5 does not exceed the coverage area of ​​the surface adhesive layer 4.

[0051] Specifically, the reinforcing structure 5 itself needs to have high temperature resistance (≥200℃), and its core functions are "toughening" and "interlocking", connecting the entire surface adhesive layer 4 into a strong and continuous whole with uniform mechanical properties, thereby giving it the characteristic of "being peelable as a whole".

[0052] Furthermore, in this embodiment, after the bottom adhesive layer 3 dries, heat-resistant fibers 52 are added to the surface adhesive layer on top of the existing low-melting-point bottom adhesive layer 3, so that the heat-resistant fibers 52 are evenly dispersed and mixed with the surface adhesive layer. The heat-resistant fibers 52 can be made of aramid short fibers with a length of about 1.5 mm, which are fully mixed with silicone in a certain volume ratio to form a fiber-reinforced mixture. Then, the mixture is applied by dispensing or potting. After curing, a fiber-reinforced explosion-proof adhesive structure can be formed. In this embodiment, the heat-resistant fibers 52 can be carbon fiber, aramid short fibers, etc.

[0053] Aramid fibers and similar heat-resistant fibers 52 are randomly distributed and interwoven within the colloid, which also serves to reinforce the colloid by binding it together. During maintenance, this "fiber-reinforced surface colloid layer 4" can be peeled off in pieces using the same heating method.

[0054] Example 3:

[0055] Based on the above-described explosion-proof adhesive structure, one embodiment provides an explosion-proof circuit board, please refer to 1 and 2. Figure 2 It includes PCBA1 and the aforementioned explosion-proof adhesive structure, with the bottom adhesive layer 3 of the explosion-proof adhesive structure coated on the surface of PCBA1.

[0056] The entire process of a blank PCB board, including SMT component mounting, DIP component insertion, or the final finished product, is referred to as PCBA1. The surface of PCBA1 is set with several electronic components 2, and the bottom adhesive layer 3 covers the solder pads of the electronic components 2 and the pads of PCBA1.

[0057] Example 4:

[0058] Based on the above-mentioned explosion-proof adhesive structure and explosion-proof circuit board, one embodiment provides an explosion-proof electronic device, such as an explosion-proof mobile phone or an explosion-proof terminal, which has the explosion-proof circuit board installed inside.

[0059] This embodiment applies the aforementioned explosion-proof circuit board to an explosion-proof mobile phone. The core of the explosion-proof mobile phone is a main circuit board, which is the explosion-proof circuit board described in this application, employing the explosion-proof adhesive structure as shown in Embodiment 1 or 2. This explosion-proof circuit board is installed inside the casing of the explosion-proof electronic device. The structure of this embodiment ensures that while meeting stringent explosion-proof certification requirements, in the event of a malfunction, the repair difficulty and cost are far lower than competing products using traditional protection solutions, giving it a significant competitive advantage in the market.

[0060] The above-described specific examples are for illustrative purposes only and are not intended to limit the scope of this invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the concept of this invention.

Claims

1. A circuit board explosion-proof adhesive structure, characterized in that, include: The bottom adhesive layer (3) is coated and cured on the surface of the circuit board; The surface adhesive layer (4) covers and cures the bottom adhesive layer (3) on the side away from the circuit board; The reinforcing structure (5) is embedded in the surface adhesive layer (4) so ​​that the surface adhesive layer (4) forms a continuous body that can be peeled off as a whole; The temperature resistance of the bottom adhesive layer (3) is lower than that of the surface adhesive layer (4) and the reinforcing structure (5).

2. The circuit board explosion-proof adhesive structure as described in claim 1, characterized in that, The difference in melting point temperature between the bottom adhesive layer (3) and the top adhesive layer (4) is not less than 60°C.

3. The circuit board explosion-proof adhesive structure as described in claim 1, characterized in that, The bottom adhesive layer (3) is polyurethane adhesive, the top adhesive layer (4) is silicone or epoxy resin adhesive, and the thickness of the top adhesive layer (4) is greater than the thickness of the bottom adhesive layer (3).

4. The circuit board explosion-proof adhesive structure as described in claim 1, characterized in that, The surface adhesive layer (4) does not exceed the coverage area of ​​the bottom adhesive layer (3).

5. The circuit board explosion-proof adhesive structure as described in claim 1, characterized in that, The reinforcing structure (5) includes a heat-resistant mesh (51) which is fully embedded in the uncured surface adhesive layer (4).

6. The circuit board explosion-proof adhesive structure as described in claim 1, characterized in that, The reinforcing structure (5) includes a plurality of heat-resistant fibers (52), which are dispersed in the surface adhesive layer (4) and mixed with the surface adhesive layer (4).

7. The circuit board explosion-proof adhesive structure as described in any one of claims 5 or 6, characterized in that, The reinforcing structure (5) does not exceed the coverage area of ​​the surface adhesive layer (4).

8. An explosion-proof circuit board, characterized in that, Includes PCBA (1) and the explosion-proof adhesive structure as described in any one of claims 1-7, wherein the bottom adhesive layer (3) of the explosion-proof adhesive structure is coated on the surface of the PCBA (1).

9. The explosion-proof circuit board as described in claim 8, characterized in that, The surface of the PCBA (1) is configured with a plurality of electronic components (2), and the bottom adhesive layer (3) covers the solder feet of the electronic components (2) and the pads of the PCBA (1).

10. An explosion-proof electronic device, characterized in that, Includes the explosion-proof circuit board as described in any one of claims 8 or 9.

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