Anti-curling enhancing method for mica paper

Abstract

The invention discloses a curling-resistant enhancing method for mica paper, which comprises the following steps: firstly, cleaning, impurity-removing, crushing and screening a mica raw material, separating out mica flakes with different particle sizes, and preparing three groups of mica paper pulp by using the mica flakes, mica flakes with different particle sizes are respectively used as the mica paper pulp of the transition layer and the surface layer. Then, manufacturing a mica paper substrate by utilizing the substrate mica paper pulp, and carrying out surface sanding treatment; spraying an adhesive containing nano silicon dioxide, a polyurethane elastomer and chitosan on the rough surface of the substrate; a semi-finished mica paper product with a double-layer structure is obtained through two-time papermaking of a papermaking machine and is attached to a substrate; and finally, carrying out segmented drying, hot-pressing shaping, calendaring and flattening treatment to obtain the finished mica paper. The method disclosed by the invention can be used for improving the wet papermaking process of the traditional mica paper and improving the curling resistance and the overall quality of the mica paper.

Description

Technical Field

[0001] The present invention relates to the technical field of mica paper processing, and specifically to an anti-curling enhancement method for mica paper used to produce mica paper with better physical properties. Background Art

[0002] In the power industry, insulating materials are a key component for the safe operation of electrical equipment. With the continuous growth of power demand and the improvement of performance requirements for electrical equipment, the performance requirements for insulating materials are also getting higher and higher. As an important insulating material, mica paper has good heat resistance, flame retardancy, high insulation, chemical stability, lightness and softness, as well as environmental friendliness. These characteristics make it an ideal choice for the main insulating material of electrical equipment and are widely used in key electrical equipment such as variable-frequency motors, high-power generators, and special transformers.

[0003] The preparation of mica paper usually adopts the wet papermaking technology. After crushing and beating mica flake raw materials and mixing them with aramid fibers, it is then formed by wet papermaking. However, during the production process of mica paper, due to uneven shrinkage of the paper, inconsistent drying, and uneven distribution of internal stress, the edges of the paper often curl. This curling not only damages the appearance quality of mica paper but also has a negative impact on its performance indicators. At the same time, it may cause problems such as dimensional deviation and interlayer peeling in subsequent processing and use. If curled mica paper is used in electrical equipment, it may reduce its insulation performance and even trigger electrical faults, thus threatening the safe operation of the equipment.

[0004] In order to improve the performance of mica paper, various enhancement methods have been adopted in the existing technologies. For example, by adding reinforcing fibers, using special surface treatment agents, adjusting papermaking process parameters, etc. to improve the mechanical strength and heat resistance of mica paper. However, these methods have some defects when enhancing the anti-curling property of mica paper. For example, adding reinforcing fibers can increase the strength of the paper, but it may increase the thickness and weight of the paper, affecting its application in electrical equipment. Using surface treatment agents can improve the anti-curling performance of the paper to a certain extent, but the uniformity and stability of the treatment agent are difficult to guarantee, and it may cause environmental pollution; adjusting papermaking process parameters can improve the uniformity of the paper, but the complexity of the process and cost control are the main problems it faces.

[0005] In summary, the existing anti-curling enhancement methods for mica paper have certain limitations and cannot simultaneously meet the requirements of mica paper in terms of mechanical strength, heat resistance, insulation, and anti-curling performance. Therefore, developing a new anti-curling enhancement method to obtain mica paper with better performance and more stable quality has important practical significance for improving the insulation performance and reliability of electrical equipment. Summary of the Invention

[0006] The technical problem solved by the present invention is to provide an anti-curling enhancement method for mica paper to solve the disadvantages in the above-mentioned background technology.

[0007] The technical problem solved by the present invention is achieved by the following technical solutions:

[0008] An anti-curling enhancement method for mica paper specifically includes the following treatment steps:

[0009] S1. Clean and remove impurities from mica raw materials, crush them into pulp by high-pressure hydraulic pulping equipment, clean, filter, and screen the crushed mica scales, and separate the parts with particle size ranges of 5 - 20 μm and 1 - 5 μm, and reserve them.

[0010] S2. Use mica scales with different particle sizes as raw materials, and prepare three groups of mica paper slurries according to the mica paper pulp-making process. The three groups of mica paper slurries are respectively:

[0011] The base mica paper slurry has no requirement for the particle size of mica scales, and the base mica paper slurry includes chopped aramid fibers accounting for 3 - 8% of the dry weight of the formed paper.

[0012] The transition layer mica paper slurry uses the mica scales with a particle size range of 1 - 5 μm obtained in step S1 as mica material.

[0013] The surface layer mica paper slurry is a mixed slurry. Among them, the slurry prepared from mica scales with a particle size range of 5 - 20 μm accounts for 30 - 50% of the mass of the mixed slurry; the slurry prepared from mica scales with a particle size range of 1 - 5 μm accounts for 10 - 20% of the mass of the mixed slurry; and it also includes the base mica paper slurry accounting for 30 - 60% of the mass of the mixed slurry.

[0014] S3. Use the base mica paper slurry as a benchmark of 1 / 2 - 2 / 3 of the thickness of the mica paper to be processed, and use a cylinder paper machine to make a mica paper base, dry and form the mica paper base, and perform surface sanding on the rough surface of the formed mica paper base to obtain a mica paper base with a one-sided rough surface.

[0015] S4. Uniformly spray an adhesive on the rough surface of the mica paper base. The adhesive is an epoxy resin-based binder, and it is doped with nano-silica accounting for 0.5 - 2% of the mass of the adhesive, polyurethane elastomer accounting for 1 - 3% of the mass of the adhesive, and chitosan accounting for 3 - 5% of the mass of the adhesive.

[0016] S5. The uniformly mixed slurry is made into a mica paper semi-finished product with a double-layer structure through papermaking twice. During the two papermaking processes, the transition layer mica paper slurry is first used as the raw material to make the transition layer paper, and then the surface layer mica paper slurry is used as the raw material to make the surface layer paper on the surface of the transition layer paper. After papermaking, a wet paper sheet of mica paper semi-finished product is obtained. The water content of the obtained wet paper sheet of mica paper semi-finished product is dried to between 15% and 20% to obtain a mica paper semi-finished product.

[0017] S6. The mica paper semi-finished product is attached to the rough surface of the mica paper substrate, and a composite mica paper semi-finished product is obtained after roll pressing. The composite mica paper semi-finished product is sent to a dynamic drying process equipment for segmented drying control:

[0018] In the first stage, the drying temperature is controlled at 60 - 80 °C and dried to a moisture content of 8% - 10%.

[0019] In the second stage, the drying temperature is controlled at 100 - 120 °C for hot pressing and shaping. The hot pressing is controlled at 0.5 - 1.2 MPa and the holding time is 3 - 5 min.

[0020] S7. The dried composite mica paper semi-finished product is subjected to calendering and leveling treatment to obtain the finished mica paper.

[0021] As a further limitation, the cleaning and impurity removal steps include using deionized water to clean and remove impurities from the mica raw material at least twice.

[0022] As a further limitation, when preparing the mica paper slurry, the sizing agent used in the base mica paper slurry, the transition layer mica paper slurry, and the surface layer mica paper slurry is an organic sizing agent, preferably an epoxy resin sizing agent, and the dosage is 5% - 15% of the dry weight of the formed paper.

[0023] As a further limitation, in the surface layer mica paper slurry, the slurry prepared from mica flakes with a particle size range of 5 - 20 μm accounts for 35% - 45% of the mass of the mixed slurry, the slurry prepared from mica flakes with a particle size range of 1 - 5 μm accounts for 12% - 18% of the mass of the mixed slurry, and the base mica paper slurry accounts for 35% - 55% of the mass of the mixed slurry.

[0024] As a further limitation, in step S2, the chopped aramid fiber used to prepare the base mica paper slurry is a modified meta-aramid chopped fiber with a single filament length of 2 - 5 mm and a single filament diameter of 10 - 20 μm.

[0025] The method for obtaining the modified meta-aramid chopped fiber is to first perform pre-modification treatment. During the modification treatment, the chopped aramid fiber is treated at 75 - 80 °C, 0.7 - 0.9×10 -3Soak and treat in a sodium dodecylbenzenesulfonate solution with a concentration of mol / L for 2 - 3 hours, filter and dry after taking out; then carry out graft modification treatment. Place the chopped aramid fiber in a mixed monomer solution containing acrylamide, ethyl acrylate and methyl methacrylate, and simultaneously add ammonium persulfate as an initiator, and react at 50 - 60 °C for 2 - 4 hours to obtain modified meta-aramid chopped fiber.

[0026] As a further limitation, in step S4, when spraying the adhesive on the rough surface of the mica paper substrate, a high-pressure airless spraying device is used to ensure that the adhesive evenly covers the rough surface of the mica paper substrate; the coating thickness of the adhesive on the mica paper substrate surface is controlled at 5 - 15 μm.

[0027] As a further limitation, during the two papermaking processes of the mica paper semi-finished product, the papermaking speeds of the transition layer paper layer and the surface layer paper layer are kept consistent to ensure the bonding strength between the two layers.

[0028] As a further limitation, in step S3, the drying process of the mica paper substrate and in step S5, the drying process of the wet paper sheet of the mica paper semi-finished product are both completed on a drum drying device.

[0029] As a further limitation, in step S6, during the process of segmental drying of the composite mica paper semi-finished product, a transverse tension is applied synchronously, and the applied transverse tension is 5 - 10 N / m to offset the shrinkage stress of the composite mica paper semi-finished product after compounding.

[0030] As a further limitation, the segmental drying control of the dynamic drying process equipment also includes setting a transition drying stage between the first stage and the second stage, and the drying temperature of this stage is 80 - 100 °C, and drying to a moisture content of 5% - 8%.

[0031] As a further limitation, the calendering and leveling treatment is carried out by a hot calender roll, and the calendering temperature is controlled at 80 - 120 °C, and the calendering pressure is 0.3 to 0.8 MPa.

[0032] Beneficial effects: The anti-curling and strengthening method for mica paper of the present invention can be improved on the existing mica paper preparation process. By optimizing the particle size separation and ratio of mica raw materials, we have achieved the uniformity and densification of the internal structure of mica paper, thereby enhancing its internal bonding force; a transition layer and a surface layer are provided on the mica paper substrate, and specific adhesives and drying processes are used to effectively improve the anti-curling performance of the formed mica paper. Through refined process control and segmental drying process, mica scales with different particle sizes form a more uniform and dense structure in the mica paper, and a transition structure is formed at the interface position between the mica paper substrate and the mica paper semi-finished product, effectively alleviating the stress difference between the substrate and the surface layer.

[0033] This method is applicable to wet-laid mica paper and can significantly improve the anti-curling performance of the mica paper after forming while maintaining its excellent physical properties. Detailed implementation manners

[0034] In order to make the technical means, creative features, achieved purposes and effects of the present invention easy to understand, the present invention will be further described below in conjunction with specific embodiments.

[0035] In the following embodiments, those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the art in the field to which this application belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art and will not be interpreted with idealized or overly formal meanings unless defined as here.

[0036] In the embodiment, the anti-curling enhancement method for mica paper is used to enhance aramid mica paper:

[0037] The original production process flow of the corresponding aramid mica paper is as follows:

[0038] After crushing the mica raw material, through cleaning, impurity removal and pulping treatment, mica flake slurry is obtained. Subsequently, the aramid fiber is pretreated, including cleaning, drying and cutting, to obtain short-cut aramid fiber suitable for mixing with mica flakes. Then, the treated mica flake slurry and the short-cut aramid fiber are mixed evenly in a certain proportion, and at the same time sizing agent is added to prepare aramid mica paper slurry.

[0039] According to the traditional wet papermaking process, the aramid mica paper slurry is formed into aramid mica paper on the wire section of the paper machine through steps such as water filtration, pressing and drying. However, the aramid mica paper prepared by this traditional process often has the problem of curling, which affects its use effect.

[0040] In order to improve this problem, this embodiment adopts the anti-curling enhancement method for mica paper to improve the above-mentioned aramid mica paper production process, and its specific operation process is as follows:

[0041] First, the mica raw material is cleaned and impurity-removed. To ensure the purity of the raw material, deionized water can be used for cleaning and impurity-removing treatment, and the treatment times are not less than two times. Then, using high-pressure hydraulic pulping equipment, the cleaned mica raw material is broken into pulp, and through the screening process, the mica flakes are screened according to the particle size, and the mica flake raw materials in the two particle size ranges of 5 - 20 μm and 1 - 5 μm are selected, dried and reserved for use.

[0042] Prepare the base mica paper slurry, transition layer mica paper slurry, and surface layer mica paper slurry according to the raw material ratios of mica scale slurry and sizing agent in the original aramid mica paper production process, where:

[0043] The base mica paper slurry uses mica scale slurry with the same concentration as in the original aramid mica paper production process. The mica material and sizing agent used in the base mica paper slurry are the same as those used in the original aramid mica paper production process. The only difference is that the base mica paper slurry also contains chopped aramid fibers accounting for 3 - 8% of the dry weight of the formed paper.

[0044] The transition layer mica paper slurry uses mica scale slurry with the same concentration as in the original aramid mica paper production process. The sizing agent used in the transition layer mica paper slurry is the same as that used in the original aramid mica paper production process, but the mica material uses mica scale raw materials within the particle size range of 1 - 5μm; using mica scales with smaller particle sizes to form a smooth transition layer.

[0045] The surface layer mica paper slurry uses mica scale slurry with the same concentration as in the original aramid mica paper production process. The sizing agent used in the surface layer mica paper slurry is the same as that used in the original aramid mica paper production process, but in the mica material, the mica scales with a particle size range of 5 - 20μm account for 40% of the mass, the mica scales with a particle size range of 1 - 5μm account for 15% of the mass, and the mica material used in the original aramid mica paper process accounts for 45% of the mass, aiming to form a uniform and dense surface structure during the subsequent forming process.

[0046] Use the base mica paper slurry to make the mica paper base. According to the benchmark of half of the thickness of the mica paper to be processed, use a cylinder paper machine to make the mica paper base. Subsequently, use a drum drying equipment to dry and form the mica paper base until the water content is less than 5%. The drum drying equipment can ensure the uniform drying of the paper, avoiding local over - drying or non - drying situations, which helps to improve the flatness and quality of the mica paper. Then, use a surface sanding equipment to sand one side surface of the mica paper base to obtain a mica paper base with a one - sided rough surface, which is convenient for subsequent adhesive spraying and laminating processes.

[0047] Before spraying the adhesive, it is necessary to ensure the cleanliness of the surface of the mica paper substrate to avoid impurities affecting the adhesion effect of the adhesive. During spraying, a high-pressure airless spraying device is used to evenly spray the adhesive onto the rough surface of the mica paper substrate at a uniform speed and pressure to ensure a uniform thickness of the adhesive layer. The coating thickness of the adhesive layer on the surface of the mica paper substrate is controlled within 5-15 μm and is proportional to the thickness of the mica paper to be processed. The adhesive is an epoxy resin-based adhesive, and 1.5% by mass of nano-silica, 2.5% by mass of polyurethane elastomer, and 4% by mass of chitosan are added to the adhesive sizing material; the addition of nano-silica improves the bonding strength and wear resistance of the adhesive; the addition of polyurethane elastomer enhances the flexibility and tear resistance of the adhesive; the introduction of chitosan not only improves the biocompatibility and environmental friendliness of the adhesive, but also provides planar ductility for paper forming, which helps to improve the anti-curling performance of the mica paper edge in cooperation with the aramid short fiber suede surface for removing surface defects in the mica paper substrate.

[0048] Then, a mica paper semi-finished product with a double-layer structure is formed by papermaking. When forming a mica paper semi-finished product with a double-layer structure, first, the transition layer mica paper pulp is used as the raw material, and a papermaking machine is used to form the transition layer paper layer. During the papermaking process, the vehicle speed needs to be controlled to maintain the uniformity of the paper layer. Subsequently, on the surface of the transition layer paper layer, the surface layer mica paper pulp is used as the raw material to form the surface layer paper layer, so that the transition layer paper layer and the surface layer paper layer are tightly combined together to form a wet paper sheet of the mica paper semi-finished product.

[0049] Then, the wet paper sheet of the mica paper semi-finished product is pre-dried to make it take shape, which is convenient for compounding with the mica paper substrate with a single-sided rough surface after spraying glue. The pre-drying treatment is also carried out in a drum dryer, and the water content of the wet paper sheet of the mica paper semi-finished product is reduced to between 15% and 18% to obtain the mica paper semi-finished product.

[0050] It should be noted that in different embodiments, the formation of the mica paper substrate with a single-sided rough surface and the mica paper semi-finished product can be carried out separately or synchronously on different production lines.

[0051] Next, the mica paper semi-finished product is bonded to the rough surface of the treated mica paper substrate, and the two are tightly combined by roll pressing to obtain a composite mica paper semi-finished product; during the roll pressing process, the roll pressing pressure is set to 0.4 MPa to ensure tight bonding and avoid excessive compression affecting the paper properties.

[0052] After bonding, the composite mica paper semi-finished product is sent to a dynamic drying process equipment for segmented drying control. By precisely controlling parameters such as drying temperature and pressure, and applying an appropriate lateral tension, the stress difference inside the paper is effectively relieved, and its anti-curling performance is improved. The segmented drying is carried out in two stages:

[0053] In the first stage, the drying temperature is set at 75°C, and the comprehensive moisture content of the paper is reduced to 8% - 10%.

[0054] In the second stage, the drying temperature is set at 115°C, and at the same time, a positive pressure of 1 MPa is applied for shaping and maintained for 3 - 5 minutes to ensure the stable structure and flat shape of the composite mica paper. At this time, the comprehensive moisture content of the paper can be reduced to less than 5%.

[0055] The dynamic drying process equipment adopts a segmented drying control strategy. By precisely regulating the drying temperature, pressure, and holding time in different stages, the effective release of internal stress and the stable shaping of the structure of the mica paper semi-finished product are achieved. The low-temperature drying in the first stage helps to slowly release the moisture inside the paper and avoid curling caused by sharp shrinkage. The high-temperature hot pressing and shaping in the second stage further consolidates the structural stability of the paper and improves its anti-curling performance.

[0056] During the segmented drying process, a transverse tension of 7.5 N / m is applied synchronously to effectively relieve the internal stress difference of the paper and offset the shrinkage stress of the composite mica paper semi-finished product after lamination, thereby improving its interlayer bonding performance and edge anti-curling performance.

[0057] After drying, the composite mica paper semi-finished product is calendered and flattened. Calendering is carried out using a hot calender roller. The calendering temperature is controlled at 120°C, and the calendering pressure is 0.8 MPa to obtain the finished mica paper. The calendering and flattening steps help to further improve the smoothness and gloss of the mica paper, and at the same time assist in enhancing its anti-curling performance.

[0058] Now, two groups of comparative documents are set. One group is used as a comparative example, and aramid mica paper is prepared by the traditional wet papermaking process. The mica flakes are not screened by particle size, and no transition layer and surface layer are set. Moreover, the drying process is a single-stage drying, and parameters such as drying temperature and pressure are not controlled in segments. The other group prepares mica paper with enhanced anti-curling performance using the scheme of this embodiment. One group of comparative documents is used to produce mica paper products with a basis weight of 160 g / m 2 and the other group of comparative documents is used to produce mica paper products with a basis weight of 180 g / m 2 The corresponding performance indicators of the mica paper products are as follows:

[0059]

[0060] As shown in the above table, by adopting the anti-curling enhancement method of the present invention, in terms of anti-curling performance, through optimizing the slurry ratio, special adhesives and segmented drying control, the anti-curling ability of mica paper has been significantly improved, and good dimensional stability and interlayer bonding strength have been maintained. The anti-curling mica paper prepared by this method shows more excellent performance than the traditional ordinary aramid mica paper in terms of tensile strength, curl rate, dielectric strength, interlayer bonding strength and surface roughness. Especially in terms of anti-curling performance, the curl degrees of Example 1 and Example 2 are respectively reduced to 0.3 - 0.5 mm / m and 0.3 - 0.5 mm / m, showing significant improvement compared with 2 - 3 mm / m and 3 - 6 mm / m of Comparative Example 1 and Comparative Example 2. In addition, after 50 wet-heat cycle tests, the change in the curl degree of the anti-curling mica paper is less than 10%, further proving its excellent anti-curling property. At the same time, the anti-curling mica paper can still maintain good dimensional stability after the wet-heat cycle test, which is particularly important for electrical insulation materials used in complex and changeable environmental conditions.

[0061] At the same time, the improvement of tensile strength and interlayer bonding strength also enhances the mechanical properties and durability of mica paper, ensuring the dimensional stability and interlayer bonding strength of mica paper in subsequent processing and use, and enabling it to show stable performance in various application scenarios. In addition, although the dielectric strength in the examples is slightly lower than that in the comparative examples, it still remains at a relatively high level, meeting the requirements of most applications. And the reduction of surface roughness further improves the smoothness and aesthetics of mica paper, broadening its application fields.

[0062] As a further improvement, this embodiment also proposes an optimization strategy for the performance of mica paper under specific application scenarios.

[0063] For example, in application scenarios that require higher dielectric strength, the dielectric performance of mica paper can be improved by adjusting the proportion of mica scales with different particle sizes in the mica scale slurry and optimizing the formula of the adhesive, such as increasing the content of nanoparticles or selecting an adhesive with a higher dielectric constant.

[0064] In the case of higher requirements for the physical properties and structural stability of mica paper, modified chopped aramid fibers can be used in the base mica paper slurry. The corresponding chopped aramid fibers are preferably meta-aramid chopped fibers with a single filament length of 2 - 5 mm and a single filament diameter of 10 - 20 μm. When performing the modification treatment, a pre-modification treatment is first carried out. During the treatment, the chopped aramid fibers are heated at 75 - 80 °C, 0.7 - 0.9×10 -3Soak and treat in a sodium dodecylbenzenesulfonate solution with a concentration of [[mol / L]] for 2 to 3 hours. Next, treat the chopped aramid fibers through graft modification technology. Polar functional groups are introduced on the surface of the modified fibers, thereby enhancing the binding force with mica flakes and adhesives. This process includes immersing the chopped aramid fibers in a mixed monomer solution containing acrylamide with a mass concentration of 0.3 to 0.5%, ethyl acrylate with a mass concentration of 0.8 to 1.5%, and methyl methacrylate with a mass concentration of 2 to 3%. In addition, ammonium persulfate is added as an initiator and reacted at 70 °C for 4 hours to obtain modified chopped aramid fibers. Incorporating such modified fibers into the base mica paper pulp can further enhance the physical properties and structural stability of the mica paper, meeting the requirements in specific application scenarios.

[0065] In addition, the segmented drying control of the dynamic drying process equipment may also include introducing a transition drying stage between the first stage and the second stage. In this transition stage, the drying temperature is set between 80 and 100 degrees Celsius until the moisture content of the material drops to 5% to 8%. This transition drying stage not only effectively avoids stress cracking caused by sudden temperature changes but also ensures the uniform evaporation of moisture inside the mica paper, thereby improving the drying efficiency.

[0066] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. A method for enhancing the anti-curling of mica paper, characterized in that: The processing steps include: S1, washing and removing impurities from the mica raw material, crushing it into pulp through a high-pressure hydraulic pulping device, washing, filtering and sieving the crushed mica flakes, separating the particles with a particle size range of 5 to 20 μm and 1 to 5 μm for standby use; S2. Using mica flakes of different particle sizes as raw materials, three groups of mica pulp materials were prepared according to the mica paper pulping process. The three groups of mica pulp materials are: The base mica pulp material has no requirement on the particle size of mica flakes, and the base mica pulp material includes short-cut aramid fibers accounting for 3 to 8% of the dry weight of the formed paper; The transition layer mica pulp material uses the mica flakes with a particle size range of 1 to 5 μm obtained in step S1 as mica material; The surface mica paper pulp is a mixed pulp, wherein the pulp prepared by mica flakes with a particle size range of 5 to 20 μm accounts for 30 to 50% of the mass of the mixed pulp; the pulp prepared by mica flakes with a particle size range of 1 to 5 μm accounts for 10 to 20% of the mass of the mixed pulp; and also includes a base mica paper pulp accounting for 30 to 60% of the mass of the mixed pulp; S3, using the base mica paper pulp according to the basis of 1 / 2 to 2 / 3 of the thickness of the mica paper to be processed, using a rotary paper machine to paper a mica paper base, drying the mica paper base to form it, and performing a surface grinding treatment on the rough surface of the formed mica paper base to obtain a mica paper base with a single-sided rough surface; S4, spraying an adhesive evenly on the rough surface of the mica paper substrate, wherein the adhesive is an epoxy resin-based adhesive and is mixed with 0.5-2% of nano-silicon dioxide by weight of the adhesive, 1-3% of a polyurethane elastomer by weight of the adhesive, and 3-5% of chitosan by weight of the adhesive; S5, the mixed slurry is passed through a paper machine for two times of papermaking to obtain a mica paper semi-finished product with a double-layer structure; during the two papermaking processes, the transition layer mica paper pulp is first used as a raw material to paper a transition layer paper layer, and then the surface layer mica paper pulp is used as a raw material to paper a surface layer paper layer on the surface of the transition layer paper layer, and after the papermaking is completed, a mica paper semi-finished wet paper sheet is obtained; the moisture content of the obtained mica paper semi-finished wet paper sheet is dried to between 15 and 20%, to obtain a mica paper semi-finished product; S6, laminating the mica paper semi-finished product to the rough surface of the mica paper substrate, and obtaining the composite mica paper semi-finished product after roller pressing and laminating; sending the composite mica paper semi-finished product to the dynamic drying process equipment for segmented drying control: In the first stage, the drying temperature is controlled at 60-80°C and dried to a moisture content of 8%-10%; In the second stage, the drying temperature is controlled at 100-120°C, and the hot pressing is performed, and the hot pressing is controlled at 0.5-1.2MPa, and the holding time is 3-5min; S7, calendering and leveling the dried composite mica paper semi-finished product to obtain finished mica paper.

2. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: The cleaning and impurity removal steps include using deionized water to clean and remove impurities from the mica raw material at least twice.

3. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: When preparing the mica pulp, the adhesive used in the base mica pulp, the transition layer mica pulp and the surface layer mica pulp is epoxy resin adhesive, and the amount used is 5% to 15% of the dry weight of the paper after molding.

4. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: In the surface mica paper pulp, the pulp prepared by mica flakes with a particle size range of 5 to 20 μm accounts for 35 to 45% of the mixed pulp mass, the pulp prepared by mica flakes with a particle size range of 1 to 5 μm accounts for 12 to 18% of the mixed pulp mass, and the base mica paper pulp accounts for 35 to 55% of the mixed pulp mass.

5. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: In step S2, the chopped aramid fibers used to prepare the base mica pulp material are modified meta-aramid chopped fibers with a monofilament length of 2 to 5 mm and a monofilament diameter of 10 to 20 μm; The modified meta-aramid short fibers are obtained by first performing a pre-modification treatment, wherein the short aramid fibers are heated at 75 to 80°C and 0.7 to 0.9×10 -3 The fibers were immersed in a mol / L sodium dodecylbenzene sulfonate solution for 2 to 3 hours, taken out and filtered and dried; then grafted and modified, the chopped aramid fibers were placed in a mixed monomer solution containing acrylamide, ethyl acrylate and methyl methacrylate, and ammonium persulfate was added as an initiator, and the reaction was carried out at 50 to 60°C for 2 to 4 hours to obtain modified meta-aramid chopped fibers.

6. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: In step S4, a high-pressure airless spraying device is used to spray the adhesive on the rough surface of the mica paper substrate; the coating thickness of the adhesive on the surface of the mica paper substrate is controlled to be 5 to 15 μm.

7. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: In step S3, the drying process of the mica paper substrate and in step S5, the drying process of the wet paper sheets of the semi-finished mica paper are both completed on a rotary drum drying device.

8. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: In step S6, transverse tension is applied to the composite mica paper semi-finished product during the staged drying process, and the applied transverse tension is 5-10 N / m.

9. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: The segmented drying control of the dynamic drying process equipment also includes setting a transition drying stage between the first stage and the second stage, the drying temperature of this stage is 80-100° C., and the moisture content is dried to 5%-8%.

10. The anti-curling enhancement method for mica paper according to claim 1, characterized in that: The calendering and smoothing treatment is carried out by using a hot pressing roller, the calendering temperature is controlled at 80-120° C., and the calendering pressure is 0.3 to 0.8 MPa.

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