A type of bend-resistant composite mica paper

Abstract

This utility model discloses a bend-resistant composite mica paper, comprising a mica paper base layer and a mica paper surface layer. The mica paper base layer is aramid fiber mica paper with one side roughened. A composite anti-bending structure layer and the mica paper surface layer are sequentially formed on the roughened surface of the mica paper base layer. The mica paper base layer, the composite anti-bending structure layer, and the mica paper surface layer are bonded together in pairs by hot pressing with an adhesive. The composite anti-bending structure layer includes a first reinforcing strip and a second reinforcing strip. The first reinforcing strip is a strip-shaped insulating film, and the second reinforcing strip is a strip-shaped insulating fiber mesh fabric. The first and second reinforcing strips are spaced apart along the length of the mica paper, and the second reinforcing strip serves as the intermediate structure on the outermost sides of both sides of the mica paper. The composite mica paper of this utility model has excellent bend resistance and can maintain excellent mechanical strength and insulation properties even under extreme environments such as high temperature and high pressure.

Description

Technical Field

[0001] This utility model relates to the field of paper-based insulation materials technology, specifically to a bend-resistant composite mica paper. Background Technology

[0002] Mica paper, a paper-based insulating material, is made from mica through thermochemical or hydraulic stripping and pulping followed by paper forming. It is renowned for its excellent electrical properties, high-temperature resistance, and chemical stability. This material is widely used as a core insulating material in electrical equipment such as motors, transformers, and generators.

[0003] Thanks to its unique material properties, mica paper typically exhibits high flexibility, which greatly facilitates its secondary processing, allowing it to be easily molded into various shapes of insulating components. However, ordinary mica paper performs poorly in terms of bending resistance, mainly due to its structural characteristics and manufacturing process. Mica sheets themselves have a layered crystalline structure with weak bonding between layers, making them prone to slippage, misalignment, and even delamination during bending, thus compromising the integrity of the overall structure. This structural damage weakens the bending resistance of mica paper, especially under complex and variable mechanical stress environments; prolonged bending can lead to structural failure. This structural damage further affects the insulation performance of mica paper, thereby shortening its service life.

[0004] Therefore, it is particularly necessary to improve existing mica paper in order to enhance its bending resistance, extend its service life, and ensure that it can better adapt to complex and changing mechanical stress environments. Utility Model Content

[0005] The technical problem solved by this utility model is to provide a bend-resistant composite mica paper, which aims to solve the problem of poor bend resistance of existing mica paper, and at the same time reduce production costs, so as to solve the defects in the above-mentioned technical background.

[0006] The technical problem solved by this utility model is achieved by the following technical solution:

[0007] A bend-resistant composite mica paper includes a mica paper base layer and a mica paper surface layer. The mica paper base layer is aramid fiber mica paper with one side being rough. A composite anti-bending structure layer and a mica paper surface layer are sequentially formed on the rough surface of the mica paper base layer. The mica paper base layer, the composite anti-bending structure layer, and the mica paper surface layer are bonded together in pairs by hot pressing with an adhesive.

[0008] The composite bending-resistant structural layer includes a first reinforcing strip and a second reinforcing strip. The first reinforcing strip is a strip-shaped insulating film, and the second reinforcing strip is a strip-shaped insulating fiber mesh fabric. The first reinforcing strip and the second reinforcing strip are spaced apart along the length of the mica paper, and the second reinforcing strip serves as the intermediate structure on the outermost sides of both sides of the mica paper.

[0009] As a further limitation, the rough surface of the mica paper base layer is obtained by mechanical polishing, and the rough surface after treatment has aramid fiber filaments protruding from the paper surface.

[0010] As a further limitation, the thickness ratio of the mica paper base layer to the mica paper surface layer is 2:1 to 3:1. This thickness ratio ensures the insulation performance of the mica paper while maintaining its overall strength and flexibility.

[0011] As a further limitation, the total thickness of the composite mica paper is 0.1 to 0.5 mm, and the sum of the thicknesses of the mica paper base layer and the mica paper surface layer in the composite mica paper is 65% to 75% of the total thickness of the composite mica paper.

[0012] As a further limitation, the adhesive is an epoxy resin adhesive.

[0013] As a further limitation, the first reinforcing strip is preferably obtained by cutting a polyester film or a polyimide film to a fixed width and then forming it.

[0014] As a further limitation, the second reinforcing strip preferably uses an insulating fiber mesh fabric woven from meta-aramid fiber filaments and then cut to a fixed width after forming.

[0015] The second reinforcing strip is preferably a mesh fabric, wherein the mesh of the mesh fabric is a diamond-shaped mesh with the long side parallel to the length direction of the mica paper or a herringbone-shaped mesh set along the length direction of the mica paper.

[0016] As a further limitation, the thickness of the first reinforcing strip is 0.02 mm to 0.05 mm; the thickness of the second reinforcing strip is 0.03 mm to 0.08 mm, and the basis weight is 30 g / m². 2 Up to 80g / m 2 .

[0017] As a further limitation, the bandwidth ratio of the first reinforcing strip to the second reinforcing strip in the composite bending structure layer is 1:1 to 2:1; the width of the first reinforcing strip is 30 to 50 mm, and during molding, a gap of 0.5 mm to 1 mm is reserved between the adjacent first and second reinforcing strips.

[0018] As a further limitation, the bending reinforcement layer has a layer of highly thermally conductive nanoparticles formed on the upper and lower surfaces of the second reinforcement strip, and the nanoparticles used in the highly thermally conductive nanoparticle layer are alumina, boron nitride or zinc oxide nanoparticles.

[0019] Beneficial effects: The fold-resistant composite mica paper of this invention significantly improves the fold resistance of mica paper; by using aramid fiber mica paper as the base layer, the overall strength and heat resistance of the paper base are enhanced, while the rough surface design increases the contact area between the adhesive and the paper base layer, thereby improving the stability of the interlayer bond; the introduction of the composite fold-resistant structural layer, especially the alternating configuration of the first and second reinforcing strips, effectively disperses the bending stress and reduces the risk of interlayer slippage and misalignment. The second reinforcing strip, as a mesh fabric, not only provides additional mechanical support but also promotes the penetration of the adhesive, forming a stronger interlayer bond. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a preferred embodiment of the present invention.

[0021] The structure consists of: 1. Mica paper surface layer; 2. Second reinforcing strip; 3. First reinforcing strip; 4. Mica paper base layer. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the following description, in conjunction with specific illustrations, further elaborates on this utility model.

[0023] See Figure 1 A preferred embodiment of a bend-resistant composite mica paper includes an independently formed mica paper surface layer 1, a mica paper base layer 4, and a composite bend-resistant structural layer formed between the mica paper surface layer 1 and the mica paper base layer 4 after sizing.

[0024] In this embodiment, the mica paper surface layer 1 can be a sheet of mica paper prepared using existing mica paper forming processes, or a standard-compliant mica paper product can be directly purchased; while the mica paper base layer 4 is made of aramid fiber mica paper. The thickness ratio of the mica paper base layer 4 to the mica paper surface layer 1 is 2.5:1, ensuring sufficient insulation performance while also possessing good overall strength and flexibility.

[0025] One side of the mica paper base layer 4 is roughened, which is achieved through mechanical sanding. This roughened surface features protruding aramid fiber filaments that are left behind from the interlacing of aramid fibers during the papermaking process of the mica paper base layer 4. Mechanical sanding further accentuates these fiber filaments, increasing the roughness of the surface. This roughened surface design aims to increase the contact area between the adhesive and the mica paper base layer 4, thereby enhancing the strength of the interlayer bond.

[0026] The design of the composite bending-resistant structural layer is the core of this utility model. The composite bending-resistant structural layer is located on the rough surface of the mica paper base layer 4, and includes alternating first reinforcing strips 3 and second reinforcing strips 2:

[0027] The first reinforcing strip 3 is a strip-shaped insulating film. In different embodiments, it can be a polyester film or a polyimide film. In this embodiment, it is a polyimide film that has been cut to a fixed width and then formed, which has good insulation properties and a certain mechanical strength.

[0028] The second reinforcing strip 2 is a strip-shaped insulating fiber mesh fabric, woven from meta-aramid fiber filaments and also cut to a fixed width. In this embodiment, the mesh of the mesh fabric is a herringbone pattern, and its structural style is as follows: Figure 1 As shown, the mesh of the mesh fabric is set along the length of the mica paper. This design not only provides additional mechanical support, but also facilitates the penetration of adhesives, forming a strong interlayer bond.

[0029] In this embodiment, the thickness of the first reinforcing strip 3 is 0.03 mm. This thickness is chosen to balance the reinforcing effect with material cost, ensuring sufficient mechanical support without excessively increasing the overall thickness and weight of the composite mica paper. The thickness of the second reinforcing strip 2 is 0.05 mm, and its basis weight is 50 g / m². 2 This configuration allows the second reinforcing strip 2 to maintain good flexibility and breathability while providing mechanical support, which is conducive to the uniform penetration of adhesive and the formation of interlayer bonding.

[0030] In the composite bending-resistant structural layer, the width of the first reinforcing strip 3 is 40mm, while the width of the second reinforcing strip 2 is 20mm. This width effectively covers critical areas, preventing stress concentration during bending, while maintaining appropriate spacing to avoid the interaction between the reinforcing strips affecting the overall performance. Simultaneously, a 0.75mm gap is reserved between the first reinforcing strip 3 and the second reinforcing strip 2. This design allows the composite mica paper some deformation space during bending, further improving its bending resistance.

[0031] In another embodiment, the second reinforcing strip 2 can also use a diamond-shaped grid design with its long side parallel to the length direction of the mica paper, and its reinforcing effect and molding stability are similar to the aforementioned method. However, it has a smaller improvement on the tensile strength of the molded mica paper, but its advantage lies in its more economical molding cost.

[0032] In the preparation process, the rough surface of the mica paper base layer 4 is first coated with an adhesive. The adhesive used is epoxy resin, which has good adhesion and heat resistance, ensuring a tight bond between the layers and withstanding high-temperature environments. Then, the first reinforcing strip 3 and the second reinforcing strip 2 are laid sequentially, and then adhesive is applied again. Finally, the mica paper surface layer 1 is laid on top, and the layers are firmly bonded together through a hot-pressing composite process to form a composite mica paper with excellent bending resistance.

[0033] It is important to note that in the final formed composite mica paper roll and the mica paper cut from the roll, the outermost sides on both sides in the width direction are reinforced with the second reinforcing strip 2 as the intermediate structure. This is because in this state, the interlayer bonding performance between the first reinforcing strip 3 and the mica paper surface layer 1 and the mica paper base layer 4 is significantly weaker than that between the second reinforcing strip 2 and them. As a mesh fabric, the second reinforcing strip 2 provides better mechanical interlocking and enhances the firmness of the interlayer bonding. Therefore, the reinforcement by the second reinforcing strip 2 can effectively prevent edge cracking and damage under continuous use, thereby improving the stability, durability and service life of the overall structure.

[0034] In this embodiment, in order to ensure the electrical insulation and performance of the mica paper, the total thickness of the composite mica paper after hot pressing is 0.3 mm, and the sum of the thicknesses of the mica paper base layer 4 and the mica paper surface layer 1 accounts for 70% of the total thickness of the composite mica paper.

[0035] Furthermore, to further enhance the thermal conductivity of the composite mica paper, a layer of highly thermally conductive nanoparticles is formed on the upper and lower surfaces of the first reinforcing strip 3 and the second reinforcing strip 2. These nanoparticle layers are made of alumina nanoparticles, which are uniformly distributed on the surface of the reinforcing strips, forming a dense thermally conductive network that effectively improves the thermal conductivity of the composite mica paper.

[0036] The bend-resistant composite mica paper prepared using the above process significantly improves its bend resistance while retaining the excellent electrical properties and high-temperature resistance of traditional mica paper. The introduction of the composite anti-bending structure layer, especially the alternating configuration of the first and second reinforcing strips, effectively disperses stress during bending, greatly reducing the risk of interlayer slippage and misalignment. Simultaneously, the roughened surface design and the addition of a high-thermal-conductivity nanoparticle layer enhance the stability of the interlayer bonding and the thermal conductivity of the composite mica paper, respectively. These innovative designs enable this bend-resistant composite mica paper to better adapt to complex and variable mechanical stress environments, extend its service life, and exhibit more reliable performance in power equipment.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of this utility model. Furthermore, it should be understood that after reading the technical content of this utility model, those skilled in the art can make various alterations, modifications, and / or variations to this utility model, and all such equivalent forms also fall within the scope of protection defined by the appended claims.

Claims

1. A bend-resistant composite mica paper, characterized in that, The composite mica paper includes a mica paper base layer and a mica paper surface layer. The mica paper base layer is aramid fiber mica paper with one side being rough. A composite bending-resistant structural layer and a mica paper surface layer are sequentially formed on the rough surface of the mica paper base layer. The mica paper base layer, the composite bending-resistant structural layer, and the mica paper surface layer are bonded together in pairs by hot pressing with an adhesive. The composite bending-resistant structural layer includes a first reinforcing strip and a second reinforcing strip. The first reinforcing strip is a strip-shaped insulating film, and the second reinforcing strip is a strip-shaped insulating fiber mesh fabric. The first reinforcing strip and the second reinforcing strip are spaced apart along the length of the mica paper, and the second reinforcing strip serves as the intermediate structure on the outermost sides of both sides of the mica paper.

2. The bend-resistant composite mica paper according to claim 1, characterized in that, The rough surface of the mica paper base layer is obtained by mechanical polishing, and the rough surface after treatment has aramid fiber filaments protruding from the paper surface.

3. The bend-resistant composite mica paper according to claim 1, characterized in that, The thickness ratio of the mica paper base layer to the mica paper surface layer is 2:1 to 3:

1.

4. The bend-resistant composite mica paper according to claim 1, characterized in that, The total thickness of the composite mica paper is 0.1~0.5mm, and the sum of the thickness of the base layer and the surface layer of the composite mica paper is 65%~75% of the total thickness of the composite mica paper.

5. The bend-resistant composite mica paper according to claim 1, characterized in that, The adhesive is an epoxy resin adhesive.

6. The bend-resistant composite mica paper according to claim 1, characterized in that, The first reinforcing strip is obtained by cutting a polyester film or a polyimide film to a fixed width and then forming it.

7. The bend-resistant composite mica paper according to claim 1, characterized in that, The second reinforcing belt uses an insulating fiber mesh fabric woven from meta-aramid fiber filaments, which is then cut to a fixed width after forming. The second reinforcing strip is a mesh fabric, the mesh of which is a diamond-shaped mesh with the long side parallel to the length direction of the mica paper or a herringbone-shaped mesh set along the length direction of the mica paper.

8. The bend-resistant composite mica paper according to claim 1, characterized in that, The thickness of the first reinforcing strip is 0.02 mm to 0.05 mm; the thickness of the second reinforcing strip is 0.03 mm to 0.08 mm, and the basis weight is 30 g / m² to 80 g / m².

9. The bend-resistant composite mica paper according to claim 1, characterized in that, The bandwidth ratio of the first reinforcing strip to the second reinforcing strip in the composite bending-resistant structural layer is 1:1 to 2:1; the width of the first reinforcing strip is 30 to 50 mm, and during molding, a gap of 0.5 mm to 1 mm is reserved between adjacent first and second reinforcing strips.

10. The bend-resistant composite mica paper according to claim 1, characterized in that, The composite bending-resistant structural layer has a layer of highly thermally conductive nanoparticles formed on the upper and lower surfaces of the second reinforcing strip. The nanoparticles used in the highly thermally conductive nanoparticle layer are alumina, boron nitride, or zinc oxide nanoparticles.

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