Aramid paper spray wet water hot rolling and pressing device and process

Abstract

This invention discloses an aramid paper spray-wetting hot rolling device and process. Along the aramid paper conveying direction on the guide rollers, the device sequentially includes an unwinding tension control mechanism, a hot rolling mill unwinding frame, a vertical spray-wetting mechanism, a moisture detection device, a preheating guiding mechanism, a hot rolling mechanism, a residual heat drying mechanism, a cooling and shaping mechanism, a thickness detection device, and a winding tension control mechanism. This invention utilizes moisture swelling to plasticize aramid fibers, avoiding paper surface defects such as fiber breakage, roller sticking, wrinkling, and fuzzing caused by dry rolling, significantly improving paper density, mechanical strength, and dielectric properties. The moisture content is precisely controllable and humidified uniformly, eliminating the deformation problems of traditional wet humidification methods. It effectively solves the performance and quality pain points of existing dry rolling processes and is suitable for the densification finishing of various meta- and para-positioned aramid papers, especially suitable for the continuous industrial production of high-flatness, high-density aramid papers for high-end electrical insulation and aerospace honeycomb substrates.

Description

Technical Field

[0001] This invention belongs to the field of aramid paper deep processing technology, specifically relating to an aramid paper spray-wet hot rolling device and process. Background Technology

[0002] Aramid paper is a special functional paper made primarily from poly(m-phenylene isophthalamide) fiber and poly(p-phenylene terephthalamide) fiber through papermaking. It possesses characteristics such as ultra-high heat resistance, excellent dielectric insulation, high mechanical strength, and resistance to chemical corrosion, making it an indispensable key material in high-end electrical equipment, aerospace, and electronic circuit substrates. The aramid paper base has loosely overlapping fibers, high porosity, and relatively low strength. Therefore, it must undergo hot rolling and densification finishing treatment to achieve a dense structure and meet performance standards for practical applications.

[0003] Currently, the industry standard uses a dry hot rolling (dry rolling / dry hot pressing) process, which directly feeds the dried aramid paper base into a hot press roller assembly, achieving fiber compaction under high temperature and pressure. However, this process has fundamental technical defects and cannot meet the quality requirements of high-end aramid paper, exhibiting the following shortcomings:

[0004] (1) Paper surface quality defects: Dry aramid fiber molecular chains have high rigidity and high glass transition temperature, and the fiber flexibility is extremely poor. When subjected to high temperature and high pressure in the dry state, it is very easy to undergo brittle fracture, resulting in rough finished paper surface, prominent fibrillary texture, and serious shedding, fuzzing, and powdering. At the same time, the dry paper rubs directly against the metal hot roller, resulting in high friction and no lubrication isolation layer, which easily leads to problems such as sticking to the roller, paper pulling, wrinkling, uneven thickness, and local holes. The paper surface has extremely poor flatness and smoothness, and problems such as uneven glue distribution and poor interface bonding are easy to occur during subsequent impregnation and lamination processing.

[0005] (2) Structural and performance defects: In the dry state, the molecular chain segments of aramid fibers have weak mobility, making it difficult for the fibers to slide, crush, and rearrange sufficiently. The fibers only form weak bonds through physical compression, resulting in low paper density after rolling, a high proportion of internal interconnected pores and large-diameter pores, and significantly insufficient mechanical properties such as tensile strength, interlayer bonding strength, folding endurance, and tear strength. The material is brittle and has a short service life. In addition, a large number of air gaps remain inside, resulting in low dielectric breakdown strength, unstable volume resistivity, and poor thermal conductivity, making it unsuitable for high-end application scenarios such as high-voltage insulation and high-temperature heat dissipation.

[0006] (3) Production stability defects: During the dry rolling process, the roller sticking and paper breakage occur frequently, the equipment downtime rate is high, the product yield rate is low, and the production cost is greatly increased.

[0007] While existing technologies have attempted to improve wet rolling processes, they mostly employ immersion or spray-type humidification methods, which suffer from problems such as poor humidification uniformity, localized over-wetting and moisture absorption deformation of the paper, inability to accurately control the moisture content in a closed-loop manner, uneven moisture distribution leading to localized wrinkling after rolling, high energy consumption in subsequent drying, and poor compatibility with continuous production lines. As a result, it is still impossible to achieve high-quality and stable wet rolling production of aramid paper.

[0008] Based on the numerous drawbacks of the existing technologies, developing a wet rolling technology for aramid paper that can fundamentally solve the defects of dry hot rolling, provide precise and controllable humidification, and is suitable for continuous production has become a core technical challenge in the preparation of high-end aramid paper in this field. Summary of the Invention

[0009] To address the technical challenges of poor paper surface quality, fiber brittleness, substandard performance, and low production stability in existing dry hot rolling processes for aramid paper, as well as the uneven humidification and uncontrolled moisture content in traditional wet rolling processes, the primary objective of this invention is to provide a spray-wet hot rolling device for aramid paper. This device, along the conveying direction of the aramid paper guide rollers, is sequentially equipped with an unwinding tension control mechanism, a vertical spray wetting mechanism, a moisture detection device, a preheating guiding mechanism, a hot rolling mechanism, a waste heat drying mechanism, a cooling and shaping mechanism, a thickness detection device, and a winding tension control mechanism.

[0010] The second objective of this invention is to provide a spray-wetting hot rolling process for aramid paper. This process employs a vertical closed-loop precision spray wetting method to accurately control the moisture content of the aramid paper at 10%-20% (paper oven-dryness to 80%-90%) before high-temperature hot rolling. Utilizing the swelling and plasticizing effect of moisture on the aramid fibers, the process improves the fibers' ability to deform under pressure, completely overcoming the inherent defects of dry rolling processes, and producing aramid paper products with high surface quality, high density, and high overall performance. This process utilizes vertical double-sided fine spraying and online closed-loop moisture content control.

[0011] The aramid paper spray wet hot rolling process described in this invention is for the densification and finishing of meta / para aramid paper, and is especially suitable for the industrial production of high-flatness, high-density aramid paper for high-end electrical insulation and aerospace honeycomb substrates.

[0012] The primary objective of this invention is achieved through the following technical solution:

[0013] An aramid paper spray-wetting hot rolling device is provided, which is arranged in sequence along the aramid paper conveying direction of the guide roller, including an unwinding tension control mechanism, a hot rolling mill unwinding frame, a vertical spray-wetting mechanism, a moisture detection device, a preheating guide mechanism, a hot rolling mechanism, a waste heat drying mechanism, a cooling and shaping mechanism, a thickness detection device, and a winding tension control mechanism.

[0014] The vertical spray humidification mechanism includes a vertical sealed humidification box, a double-sided spray assembly, and a PID automatic water volume control module.

[0015] The double-sided spraying components are symmetrically distributed on both sides of the aramid paper conveying path. Each set of double-sided spraying components consists of several fine atomizing nozzles arranged at equal intervals. The spraying angle of the fine atomizing nozzles matches the width of the paper to achieve uniform spraying that covers the entire paper surface.

[0016] The moisture detection device is equipped with an online non-contact moisture content detection probe. The detection end of the online non-contact moisture content detection probe is facing the surface of the aramid paper to collect paper moisture content data in real time.

[0017] The signal output terminal of the online non-contact moisture content detection probe is electrically connected to the PID automatic water volume control module. The PID automatic water volume control module is linked with the water supply control valve and air pressure control valve of the double-sided spray assembly to achieve real-time closed-loop adjustment of the spray volume.

[0018] The hot rolling mechanism adopts a high-precision hot rolling roll group. The rolling gap of the hot rolling roll group can be precisely adjusted and is coaxial with the center line of the aramid paper conveying.

[0019] Furthermore, the top of the vertical sealed humidification box is provided with a paper inlet, and the bottom of the vertical sealed humidification box is provided with a paper outlet. The aramid paper passes vertically from top to bottom through the paper inlet, the inner cavity of the vertical sealed humidification box, and the paper outlet to achieve vertical transmission humidification. Guide rollers are provided at both the paper inlet and the paper outlet of the vertical sealed humidification box to ensure smooth transmission of the aramid paper and avoid friction damage between the paper surface and the box.

[0020] Furthermore, the vertical sealed humidification chamber is equipped with multiple moisture recovery guide hoods on its inner side, allowing moisture to form water droplets along the inner side of the chamber for collection, preventing water mist leakage and lateral deviation during paper conveying. Furthermore, the PID automatic water volume control module includes a return water collection tank, a water supply pipeline, a pressure regulating valve, a pressure gauge, a variable frequency water supply pump, a water storage tank, a return water pipeline, and a detachable fixing bracket. One end of the water supply pipeline is connected to the water storage tank, and the other end is connected to each fine atomizing nozzle. The variable frequency water supply pump, pressure gauge, and pressure regulating valve are installed in series on the water supply pipeline. The fine atomizing nozzles have built-in flow and mist particle adjustment ports. By regulating the water supply pressure through the pressure regulating valve, and in conjunction with the nozzle's own adjustment ports, precise adjustment of both spray volume and spray fineness can be achieved, accurately controlling the aramid paper's dryness to 80%~90%. The integrated water return collection tank is located at the bottom of the vertical sealed humidification box and above the paper outlet. It is used to collect water flowing from the inner wall of the box and excess spray water. The two ends of the water return pipeline are connected to the water return collection tank and the water storage tank, respectively, forming a closed-loop water circulation system of water supply-spray-return-resupply. This can not only prevent spray drip water from contaminating the paper surface, but also realize the recycling of water resources. The detachable fixed bracket securely installs the vertical sealed humidification box at the front end of the hot rolling mill unwinding frame. After the aramid paper is output from the paper outlet, it can directly enter the feeding end of the hot rolling mill mechanism, realizing seamless connection between the wetting and hot rolling processes and completing continuous production.

[0021] Furthermore, the online non-contact moisture content detection probe is equipped with a PID controller.

[0022] Furthermore, the rolls in the hot-pressing roll assembly are mirror alloy rolls, and the rolls have built-in circulating heat transfer oil heating elements or electric heating rods, with a surface temperature uniformity deviation of ≤±2℃.

[0023] The second objective of this invention is achieved through the following technical solution:

[0024] A spray-wet hot rolling process for aramid paper, implemented using a spray-wet hot rolling device for aramid paper, specifically includes the following steps:

[0025] (1) Tension unwinding: The aramid paper base paper is unwound through the unwinding tension control mechanism. The unwinding tension is adjusted to be constant, so that the aramid paper is vertically conveyed to the vertical spray wetting mechanism at a stable speed to avoid paper loosening and wrinkling.

[0026] (2) Closed-loop precision spraying and wetting: A vertical spraying and wetting mechanism is adopted. The double-sided spraying component is activated to perform fine atomized spraying and humidification on both sides of the aramid paper. An online non-contact moisture content detection probe is used to detect the real-time moisture content of the paper and transmit the signal to the PID automatic water volume control module. The PID automatic water volume control module compares the preset moisture content threshold and automatically adjusts the spraying pressure and spray volume to accurately and stably control the moisture content of the aramid paper within the set range, ensuring uniform moisture distribution across the entire paper surface.

[0027] (3) Preheating and guiding: The aramid paper, after being sprayed with water, is preheated at low temperature by the preheating and guiding mechanism to eliminate the internal stress of the paper and maintain the stable moisture content. Then it is smoothly fed into the hot rolling mechanism.

[0028] (4) Wet hot rolling: Wet aramid paper is fed into the hot rolling mechanism, and the hot rolling mechanism is adjusted to the set hot rolling temperature and rolling pressure to continuously densify the paper; the moisture evaporates rapidly under the action of hot pressing, which on the one hand forms internal pressure to assist in compaction of the fiber, and on the other hand moistens the fiber to soften and plasticize it. Under the action of pressure, the fiber slides, crushes, and rearranges itself to form a high-strength bond;

[0029] (5) Waste heat drying and cooling and shaping: The aramid paper after wet hot rolling is dried by a waste heat drying mechanism to remove residual free moisture, and then cooled to room temperature by a cooling and shaping mechanism. The paper size is then measured by a thickness detection device.

[0030] (6) Constant tension winding: Adjust the winding tension of the winding tension control mechanism to smoothly wind up the finished high-density aramid paper and avoid winding deformation.

[0031] Furthermore, in step (2), the moisture content of the aramid paper is precisely controlled at 10%-20%.

[0032] Furthermore, the low-temperature preheating temperature mentioned in step (3) is 60℃-80℃ to avoid deformation of the wet paper caused by sudden cooling and heating.

[0033] Furthermore, in step (4), the hot rolling temperature set by the hot rolling mechanism is 190℃-250℃, and the rolling pressure is 1.0MPa-2.2MPa.

[0034] The working principle and process of this invention are as follows:

[0035] (a) The present invention uses water spraying followed by hot rolling. The water has a swelling, plasticizing and lubricating effect on the aramid fibers, which greatly reduces the fiber rigidity and improves the flexibility. It avoids fiber breakage during the hot rolling process and eliminates the problems of paper shedding, fuzzing and roughness from the root. At the same time, the water forms a thin liquid film on the paper surface, which reduces the frictional resistance between the paper and the hot roller, and eliminates the problems of sticking to the roller, wrinkles and holes. The finished paper surface is smooth and delicate, with high flatness and excellent thickness uniformity.

[0036] (b) The plasticizing and deformation ability of aramid fibers is improved in wet conditions. During hot pressing, the fibers are fully compacted and bonded, resulting in a significant increase in paper density, substantial closure of internal pores, a sharp drop in porosity, and a significant enhancement in the bonding force between fibers. Compared with dry rolling process, the tensile strength, folding endurance, and dielectric breakdown strength of paper are significantly improved, and the mechanical properties and dielectric insulation properties fully meet the requirements of high-end applications.

[0037] (c) The vertical double-sided fine spray and online moisture content closed-loop control are adopted to achieve uniform humidification across the entire area and precise control of moisture content, avoiding over-humidification and deformation problems caused by immersion humidification. It is compatible with high-speed continuous production lines, with low equipment downtime and significantly improved product yield.

[0038] (d) The device can be directly connected to the existing aramid paper production line without major equipment modifications. The process parameters are adjustable and it is suitable for rolling and finishing of different thicknesses and types of meta / para aramid paper, with strong industrial adaptability.

[0039] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0040] (1) The technical solution as a whole is novel.

[0041] This invention is the first to propose a complete set of equipment and process routes that integrates vertical double-sided fine spray wetting, online closed-loop moisture content detection and control, preheating guidance, and wet hot rolling. No similar structural or process combinations have been publicly reported in existing technologies. Through vertical arrangement and closed-loop humidification control, uniform, stable, and precise control of the moisture content of aramid paper before hot rolling is achieved. This overall technical solution is novel compared to existing dry hot rolling processes for aramid paper and traditional extensive wet processing techniques.

[0042] (2) Breaking through the inherent defects of dry rolling from the mechanism level, demonstrating outstanding creativity.

[0043] Traditional dry hot rolling has long suffered from insurmountable drawbacks such as fiber brittleness, paper surface fuzzing, roller sticking and wrinkling, low density, high porosity, and insufficient dielectric properties. Industry practices have largely focused on optimizing parameters such as temperature and pressure, but these have not fundamentally solved the problem. This invention creatively utilizes the swelling, plasticizing, and lubricating effects of moisture on aramid fibers, placing the fibers in a plasticized and pliable state before hot rolling. This significantly enhances fiber deformation, slippage, and rearrangement capabilities, eliminating fiber brittleness from a fundamental mechanism perspective and removing surface and structural defects caused by dry rolling. It achieves a high-density, high-strength, and highly smooth paper surface that traditional dry rolling cannot achieve. This technological approach is not readily apparent and possesses significant advantages over existing dry hot rolling processes for aramid paper and traditional extensive wet processing methods.

[0044] (3) Achieve precise and controllable humidification process, overcoming common problems of traditional humidification methods.

[0045] Conventional wet processing methods such as immersion and spraying suffer from problems such as uneven humidification, localized over-humidification, paper deformation, large fluctuations in moisture content, and high subsequent drying loads. This invention employs fine atomized spraying combined with online non-contact moisture content detection and PID automatic adjustment to achieve uniform humidification across the entire width and real-time stable moisture content control. This ensures effective wet hot rolling while preventing paper from absorbing moisture, deforming, wrinkling, and breaking, significantly improving continuous production stability and product yield, achieving unexpected technical results.

[0046] (4) Wet hot rolling forms a dual compaction mechanism, resulting in significant performance improvement.

[0047] During the hot rolling process, the moisture inside the paper is rapidly vaporized by heat, forming a dual compaction effect of external mechanical rolling pressure and internal steam expansion pressure. This makes the fibers more fully crushed and more tightly bonded, and the paper density, internal bond strength, folding endurance and dielectric breakdown strength are all greatly improved. The performance is significantly better than the traditional dry rolling process, which shows significant technological progress.

[0048] (5) The project has strong applicability and has industrialization promotion value.

[0049] The device of this invention has a compact structure and can be directly connected in series with existing aramid paper making and hot rolling production lines without the need for large-scale modification of the main equipment. It has low investment, strong compatibility, and stable operation, and solves the long-standing engineering problem of the difficulty in balancing surface quality and comprehensive performance of high-end aramid paper. It has significant industrial application value. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the overall structure of the traditional dry hot rolling process device in Comparative Example 1;

[0051] Figure 2 This is a schematic diagram of the overall structure of the aramid paper spray-wetting hot rolling device in Example 1;

[0052] Figure 3 This is a schematic diagram of the internal structure of the vertical spray wetting mechanism and moisture detection device in Example 1;

[0053] Among them, 1-unwinding tension control mechanism, 2-vertical spray wetting mechanism, 3-moisture detection device, 4-preheating guide mechanism, 5-hot rolling mill, 6-waste heat drying mechanism, 7-cooling and shaping mechanism, 8-thickness detection device, 9-winding tension control mechanism, 10-guide roller, 11-aramid paper; 12-hot rolling mill unwinding frame; 21-vertical sealed humidification box, 22-double-sided spray assembly, 23-PID automatic water volume control module; 211-paper inlet, 212-paper outlet, 213-moisture recovery guide hood, 221-atomizing nozzle, 231-return water collection tank, 232-water supply pipeline, 233-pressure regulating valve, 234-pressure gauge, 235-variable frequency water supply pump, 236-water storage tank, 237-return water pipeline, 238-detachable fixed bracket, 31-online non-contact moisture content detection probe. Detailed Implementation

[0054] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto. All materials used in the examples of the present invention are commercially available.

[0055] Example 1

[0056] like Figure 2 As shown, the aramid paper spray-wetting hot rolling device described in this embodiment is provided with the following components in sequence along the conveying direction of the aramid paper 11 on the guide roller 10: unwinding tension control mechanism 1, hot rolling mill unwinding frame 12, vertical spray-wetting mechanism 2, moisture detection device 3, preheating guide mechanism 4, hot rolling mechanism 5, residual heat drying mechanism 6, cooling and shaping mechanism 7, thickness detection device 8, and winding tension control mechanism 9.

[0057] like Figure 3 As shown, the vertical spray humidification mechanism 2 includes a vertical sealed humidification box 21, a double-sided spray assembly 22, an online non-contact moisture content detection probe 31, and a PID automatic water volume control module 23. In this embodiment, the vertical spray humidification mechanism 2 is made of 304 stainless steel and has an overall rectangular vertical sealed structure. The box height is 1200mm, and the inner cavity width is adapted to the production requirements of wide-width aramid paper.

[0058] The double-sided spray assembly 22 is symmetrically distributed on both sides of the aramid paper conveying path. Each double-sided spray assembly 22 consists of several fine atomizing nozzles 221 arranged at equal intervals. The spray angle of the fine atomizing nozzles 221 is matched with the width of the paper to achieve uniform spraying that covers the entire paper surface.

[0059] The moisture detection device 3 is equipped with an online non-contact moisture content detection probe 31. The detection end of the online non-contact moisture content detection probe 31 is facing the surface of the aramid paper to collect paper moisture content data in real time.

[0060] The signal output terminal of the online non-contact moisture content detection probe 31 is electrically connected to the PID automatic water volume control module 23. The PID automatic water volume control module 23 is linked with the water supply control valve and air pressure control valve of the double-sided spray assembly 22 to achieve real-time closed-loop adjustment of the spray volume.

[0061] The hot rolling mechanism 5 adopts a high-precision hot rolling roll group. The rolling gap of the hot rolling roll group can be precisely adjusted and is coaxial with the conveying center line of the aramid paper 11.

[0062] Furthermore, the top of the vertical sealed humidification box 21 is provided with a paper inlet 211, and the bottom of the vertical sealed humidification box is provided with a paper outlet 212.

[0063] Furthermore, the vertical sealed humidification box 21 is provided with multiple moisture recovery guide hoods 213 (preferably 4) on the inner side, so that moisture forms water droplets along the inner side of the vertical sealed humidification box, preventing water mist leakage and preventing lateral deviation during paper conveying.

[0064] Furthermore, the PID automatic water volume control module 23 includes a return water collection tank 231, a water supply pipeline 232, a pressure regulating valve 233, a pressure gauge 234, a variable frequency water supply pump 235, a water storage tank 236, a return water pipeline 237, and a detachable fixing bracket 238. One end of the water supply pipeline 232 is connected to the water storage tank 236, and the other end is connected to each fine atomizing nozzle 221. The variable frequency water supply pump 235, pressure gauge 234, and pressure regulating valve 233 are installed in series on the water supply pipeline 232. The fine atomizing nozzles 221 have their own flow rate and mist particle adjustment ports. By regulating the water supply pressure through the pressure regulating valve 233, and in conjunction with the nozzle's own adjustment port, dual precise adjustment of spray volume and spray fineness can be achieved, thus controlling the dryness of the aramid paper. The humidification rate is precisely controlled between 80% and 90%. The return water collection tank 231 is integrated at the bottom of the vertical sealed humidification box 21 and located above the paper outlet 212. It is used to collect water flowing from the inner wall of the box and excess spray water. The two ends of the return water pipe 237 are connected to the return water collection tank 231 and the water storage tank 236 respectively, forming a closed-loop water circulation system of water supply-spray-return water-resupply. This can not only prevent spray drip water from contaminating the paper surface, but also realize the recycling of water resources. The detachable fixed bracket 238 securely installs the vertical sealed humidification box 21 at the front end of the hot rolling mill unwinding frame 12. After the aramid paper 11 is output from the paper outlet 212, it can directly enter the feeding end of the hot rolling mill mechanism 5, realizing seamless connection between the wet and hot rolling processes and completing continuous production.

[0065] Furthermore, the online non-contact moisture content detection probe 31 is equipped with a PID controller.

[0066] Furthermore, the preheating guide mechanism 4 adopts a low-temperature guide roller, and the preheating temperature is controlled at 60℃-80℃ to avoid deformation caused by sudden cooling and heating of wet paper.

[0067] Furthermore, the rolls in the hot rolling mechanism 5 (hot rolling roll group) are mirror alloy rolls, and the rolls have built-in circulating heat transfer oil heating elements or electric heating rods, and the surface temperature uniformity deviation of the rolls is ≤±2℃.

[0068] This invention embodiment establishes a closed-loop automatic control logic based on a pre-set target moisture content of 10%-20%, as follows:

[0069] Online detection process: The non-contact moisture content detection probe 31 collects the moisture content data of the aramid paper from the vertical spray wetting mechanism 2 in real time and feeds the detection signal back to the PID controller;

[0070] Signal comparison and control: The PID controller compares the detected value with the preset target moisture content in real time. When the moisture content deviates from the set value, it outputs the corresponding control signal to drive the variable frequency water pump 235 to adjust the speed and cooperate with the pressure regulating valve 233 to fine-tune the pipeline water pressure.

[0071] Water supply and return process: Water in storage tank 236 is pressurized by variable frequency water pump 235 and stabilized by pressure regulating valve 233, and then transported to vertical spray wetting mechanism 2 through water supply pipeline 232 to humidify or adjust the humidity of aramid paper; the return water after the process cycle in the equipment is collected in the return water collection tank 231 and returned to storage tank 236 through return water pipeline 237 to realize the recycling of water resources;

[0072] Feedback and closed-loop mechanism: Pressure gauge 234 monitors the water supply pressure in the water supply pipeline 232 in real time, and works with the PID controller to complete the auxiliary closed-loop control of the pressure to ensure stable water supply flow and thus ensure the accuracy of moisture content adjustment; Non-contact moisture content detection probe 23 continuously collects and updates moisture content data to form a complete closed loop of "detection-comparison-control-feedback", so that the moisture content of aramid paper is always stable within the target range.

[0073] Example 2

[0074] The aramid paper spray-wet hot rolling process described in this embodiment is implemented based on an aramid paper spray-wet hot rolling device, and the process specifically includes the following steps:

[0075] (1) Tension unwinding: Select 0.05mm thick interposition aramid paper 11 base paper, and feed the paper to the aramid paper spraying and wetting hot rolling device through guide roller 10; unwind the aramid paper 11 base paper through unwinding tension control mechanism 1, adjust the unwinding tension to be constant (50N), so that the aramid paper is vertically conveyed to the vertical spraying and wetting mechanism 2 at a stable speed, so as to avoid paper loosening and wrinkling;

[0076] (2) Closed-loop precision spraying and wetting: The vertical spraying and wetting mechanism 2 is used for closed-loop precision spraying and wetting. The double-sided spraying component 22 is activated to perform fine atomized spraying and humidification on both sides of the aramid paper 11. The online non-contact moisture content detection probe 31 is used to detect the real-time moisture content of the paper and transmit the signal to the PID water volume automatic control module 23. The PID water volume automatic control module 23 compares the preset moisture content threshold and automatically adjusts the spraying pressure and spray volume to accurately and stably control the moisture content of the aramid paper 11 within the set range (11%), ensuring uniform moisture distribution across the entire paper surface.

[0077] (3) Preheating and guiding: The aramid paper 11 after humidification is preheated at a low temperature by the preheating and guiding mechanism 4, with the temperature set at 70°C, to avoid deformation caused by sudden cooling and heating of the wet paper, eliminate internal stress of the paper, maintain stable moisture content, and then smoothly fed into the hot rolling mechanism 5; at this time, the preheating and guiding mechanism 4 is a low temperature guiding roller.

[0078] (4) Wet hot rolling: The wet aramid paper is fed into the hot rolling mechanism 5 (hot rolling roll group), and the hot rolling mechanism 5 (hot rolling roll group) is adjusted to the set hot rolling temperature (230℃) and rolling pressure (1.5MPa) to continuously densify the paper; the moisture evaporates rapidly under the action of hot pressing, which on the one hand forms internal pressure to assist in compaction of the fiber, and on the other hand swells the fiber to soften and plasticize it. Under the action of pressure, the fiber slides, crushes, and rearranges itself to form a high-strength bond;

[0079] (5) Waste heat drying and cooling and shaping: The waste heat drying temperature is set to 120℃. The aramid paper after rolling is dried by the waste heat drying mechanism 6 to remove residual free moisture, and then cooled to room temperature by the cooling and shaping mechanism 7 to stabilize the paper size and structure.

[0080] (6) Constant tension winding: The thickness is detected by the thickness detection device 8, and the winding tension is adjusted by the winding tension control mechanism 9 to smoothly wind up the finished high-density aramid paper, avoiding winding deformation, and thus preparing aramid paper products with high surface quality, high density and high comprehensive performance.

[0081] Comparative Example 1

[0082] Adopting such Figure 1The conventional dry hot rolling process device shown has an unwinding tension control mechanism 1, a hot rolling mill unwinding frame 12, a hot rolling mechanism 5, and a winding tension control mechanism 9 arranged sequentially along the conveying direction of the aramid paper 11 on the guide roller 10. The same batch of aramid paper base paper is selected, and the hot pressing temperature, linear pressure, and conveying speed are completely consistent with those in Example 2. No spray wetting treatment is performed. Table 1 below shows the comparison of aramid paper performance and paper surface condition.

[0083] Table 1

[0084]

[0085] The test results in Table 1 show that the process of this invention completely overcomes the defects of traditional dry rolling process, and achieves breakthrough improvements in paper surface quality, density, mechanical properties and dielectric properties, with extremely significant technical effects.

[0086] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. An apparatus for spray-drying and hot-rolling aramid paper, characterized in that, Along the aramid paper conveying direction of the guide roller, the device is sequentially equipped with an unwinding tension control mechanism, a hot rolling mill unwinding frame, a vertical spray wetting mechanism, a moisture detection device, a preheating guide mechanism, a hot rolling pressing mechanism, a waste heat drying mechanism, a cooling and shaping mechanism, a thickness detection device, and a winding tension control mechanism. The vertical spray humidification mechanism includes a vertical sealed humidification box, a double-sided spray assembly, and a PID automatic water volume control module. The double-sided spraying components are symmetrically distributed on both sides of the aramid paper conveying path. Each set of double-sided spraying components consists of several fine atomizing nozzles arranged at equal intervals. The spraying angle of the fine atomizing nozzles matches the width of the paper to achieve uniform spraying that covers the entire paper surface. The moisture detection device is equipped with an online non-contact moisture content detection probe. The detection end of the online non-contact moisture content detection probe is facing the surface of the aramid paper to collect paper moisture content data in real time. The signal output terminal of the online non-contact moisture content detection probe is electrically connected to the PID automatic water volume control module. The PID automatic water volume control module is linked with the water supply control valve and air pressure control valve of the double-sided spray assembly to achieve real-time closed-loop adjustment of the spray volume. The hot rolling mechanism adopts a high-precision hot rolling roll group. The rolling gap of the hot rolling roll group can be precisely adjusted and is coaxial with the center line of the aramid paper conveying.

2. The aramid paper spray-wet hot rolling device according to claim 1, characterized in that, The vertical sealed humidification chamber has a paper inlet at the top and a paper outlet at the bottom. The aramid paper passes vertically through the paper inlet, the inner cavity of the vertical sealed humidification chamber, and the paper outlet from top to bottom, achieving vertical transmission humidification. Guide rollers are provided at both the paper inlet and the paper outlet of the vertical sealed humidification chamber.

3. The aramid paper spray-wet hot rolling device according to claim 1, characterized in that, The vertical sealed humidification box is equipped with multiple moisture recovery guide hoods on its inner side.

4. The aramid paper spray-wet hot rolling device according to claim 1, characterized in that, The PID automatic water volume control module includes a return water collection tank, a water supply pipeline, a pressure regulating valve, a pressure gauge, a variable frequency water supply pump, a water storage tank, a return water pipeline, and a detachable fixing bracket. One end of the water supply pipeline is connected to the water storage tank, and the other end is connected to each fine atomizing nozzle. The variable frequency water supply pump, pressure gauge, and pressure regulating valve are installed in series on the water supply pipeline. The fine atomizing nozzles have their own flow rate and mist particle adjustment ports. By regulating the water supply pressure through the pressure regulating valve, and in conjunction with the nozzle's own adjustment ports, dual precision in spray volume and mist fineness can be achieved. The aramid paper's dryness is precisely controlled between 80% and 90% through adjustment. The integrated water return collection tank is located at the bottom of the vertical sealed humidification box and above the paper outlet, used to collect water flowing from the inner wall of the box and excess spray water. The two ends of the water return pipeline are connected to the water return collection tank and the water storage tank, forming a closed-loop water circulation system of water supply-spray-water return-resupply. The detachable fixing bracket securely installs the vertical sealed humidification box at the front end of the hot rolling mill unwinding frame, allowing the aramid paper to directly enter the feeding end of the hot rolling mill mechanism after being output from the paper outlet.

5. The aramid paper spray-wet hot rolling device according to claim 1, characterized in that, The online non-contact moisture content detection probe is equipped with a PID controller.

6. The aramid paper spray-wet hot rolling device according to claim 1, characterized in that, The rolls in the hot-pressing roll assembly are mirror alloy rolls, and the rolls have built-in circulating heat transfer oil heating elements or electric heating rods. The surface temperature uniformity deviation of the rolls is ≤±2℃.

7. An aramid paper spray-wet hot rolling process, implemented based on the aramid paper spray-wet hot rolling apparatus according to any one of claims 1 to 6, characterized in that, The process specifically includes the following steps: (1) Tension unwinding: The aramid paper base paper is unwound through the unwinding tension control mechanism. The unwinding tension is adjusted to be constant, so that the aramid paper is vertically conveyed to the vertical spray wetting mechanism at a stable speed to avoid paper loosening and wrinkling. (2) Closed-loop precision spraying and wetting: A vertical spraying and wetting mechanism is adopted. The double-sided spraying component is activated to perform fine atomized spraying and humidification on both sides of the aramid paper. An online non-contact moisture content detection probe is used to detect the real-time moisture content of the paper and transmit the signal to the PID automatic water volume control module. The PID automatic water volume control module compares the preset moisture content threshold and automatically adjusts the spraying pressure and spray volume to accurately and stably control the moisture content of the aramid paper within the set range, ensuring uniform moisture distribution across the entire paper surface. (3) Preheating and guiding: The aramid paper, after being sprayed with water, is preheated at low temperature by the preheating and guiding mechanism to eliminate the internal stress of the paper and maintain the stable moisture content. Then it is smoothly fed into the hot rolling mechanism. (4) Wet hot rolling: Wet aramid paper is fed into the hot rolling mechanism, and the hot rolling mechanism is adjusted to the set hot rolling temperature and rolling pressure to continuously densify the paper; the moisture evaporates rapidly under the action of hot pressing, which on the one hand forms internal pressure to assist in compaction of the fiber, and on the other hand moistens the fiber to soften and plasticize it. Under the action of pressure, the fiber slides, crushes, and rearranges itself to form a high-strength bond; (5) Waste heat drying and cooling and shaping: The aramid paper after wet hot rolling is dried by a waste heat drying mechanism to remove residual free moisture, and then cooled to room temperature by a cooling and shaping mechanism. The paper size is then measured by a thickness detection device. (6) Constant tension winding: Adjust the winding tension of the winding tension control mechanism to smoothly wind up the finished high-density aramid paper and avoid winding deformation.

8. The aramid paper spray-wet hot rolling process according to claim 7, characterized in that, In step (2), the moisture content of the aramid paper is precisely controlled between 10% and 20%.

9. The aramid paper spray-wet hot rolling process according to claim 7, characterized in that, The low-temperature preheating temperature mentioned in step (3) is 60℃-80℃.

10. The aramid paper spray-wet hot rolling process according to claim 7, characterized in that, In step (4), the hot rolling temperature of the hot rolling mechanism is set to 190℃-250℃, and the rolling pressure is 1.0MPa-2.2MPa.

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