High-temperature-resistant magnetic conductive material, preparation method thereof and electronic cigarette containing high-temperature-resistant magnetic conductive material

Abstract

The invention discloses a high-temperature-resistant magnetic conductive material, a preparation method thereof and an electronic cigarette comprising the high-temperature-resistant magnetic conductive material, and the preparation method comprises the following steps: sequentially carrying out heat treatment and surface coating on a nanocrystalline strip to obtain a single-layer structure nanocrystalline strip subjected to heat treatment and surface coating, then the nanocrystalline strip is processed in the following mode in any sequence: i) the surface coating glue is used as an adhesive, and a plurality of nanocrystalline strips with the single-layer structure are mutually attached to form a composite multi-layer structure; ii) carrying out crushing treatment to generate cracks; iii) sequentially passing through a high-temperature and high-humidity area and a low-temperature area which are alternately arranged. According to the preparation method disclosed by the invention, destressing treatment in high and low temperature environments is particularly introduced, so that the problem that the magnetic conductivity of the magnetic conductive material is greatly changed in a high-temperature environment is solved, and the high-temperature stability of the product is improved. The preparation method is simple, continuous production can be realized, and the prepared magnetic conductive material has the characteristics of high temperature resistance, high magnetic conductivity and low loss, and can be randomly cut according to the size of a coupling coil to meet the requirements of electronic cigarettes with different sizes.

Description

Technical Field

[0001] This invention belongs to the field of magnetic materials technology, and specifically relates to a high-temperature resistant magnetically conductive material, its preparation method, and an electronic cigarette containing the same. Background Technology

[0002] Heating methods in heated electronic cigarettes (HNB) are divided into resistance heating and electromagnetic induction heating. Resistance heating has technical drawbacks such as uneven heating, low efficiency, easy damage to the heating element, and inconvenient cleaning. It has been gradually replaced by the new electromagnetic induction heating method. The core heating components of electromagnetic induction heating are the electromagnetic induction coil of the heater and the induction metal body inside the cartridge. The basic principle is that a high-speed changing high-frequency high-voltage current (i.e., alternating current) passes through the induction coil, generating a changing alternating magnetic field. This alternating magnetic field cuts the alternating magnetic field lines, inducing eddy currents on the metal induction body inside the cartridge. The high-speed movement of charge carriers generates heat energy, which is then used to heat the tobacco.

[0003] Without the restraint of a soft magnetic material, the alternating magnetic field generated by the induction coil will diverge, resulting in low heating efficiency and interference with other metal components outside the coil. To improve the heating efficiency of electromagnetic induction heating electronic cigarettes and reduce the impact of magnetic field divergence on the surrounding environment, a magnetically conductive material should be added to the outside of the coil to restrain and shield the magnetic field generated by the coil. Since the heating temperature of induction heating is generally between 100 and 300 degrees Celsius, such a high-temperature application environment requires high temperature resistance from the magnetically conductive material. It is essential to ensure that the magnetic permeability maintains minimal fluctuations under high-temperature conditions, thereby ensuring uniform heating and a better flavor.

[0004] Currently, most magnetic materials used are ferrites. However, ferrites have a low Curie temperature, around 200°C. Above the Curie temperature, the permeability drops sharply, and the material changes from ferromagnetic to paramagnetic, losing its application value. Furthermore, ferrites have low saturation magnetic induction, requiring a large thickness to prevent saturation when the current is large, which cannot meet the requirements of ultra-light and ultra-thin materials. In addition, sintered ferrite materials are very brittle and have poor flexibility, making them difficult to process when winding coils.

[0005] Nanocrystalline soft magnetic materials possess advantages such as high saturation magnetic induction, high initial permeability, low coercivity, and low high-frequency loss. Furthermore, their Curie temperature reaches over 500℃. When applied to heating components, they significantly improve heating efficiency and shield interference to other metal parts, making them promising alternative materials. However, while nanocrystalline materials have a high Curie temperature, meeting high-temperature operating conditions, their high permeability after heat treatment and significant eddy current losses lead to severe heat generation within the nanocrystalline magnetic material itself. This heat is transferred to the outer wall of the handheld electronic cigarette, resulting in a poor user experience and wasted energy, thus reducing the heating efficiency of the metal sensor inside the cartridge. Previous methods of fragmenting and insulating nanocrystalline materials have, to some extent, increased their usage frequency and reduced eddy current losses, thus decreasing heat generation. However, these methods are more commonly used in wireless charging. A common approach involves heat-treating nanocrystalline strips, bonding double-sided adhesive or a protective film to one or both sides, and then crushing them to create smaller units. Insulating media is filled into the gaps to reduce coupling losses and heat generation. While this preparation method can reduce eddy current losses, the magnetic material is a composite material made of nanocrystalline ribbons and double-sided adhesive, not just a single nanocrystalline material. Although nanocrystalline materials are very stable at 100–300°C, the composite material exhibits significant fluctuations in magnetic permeability at high temperatures. Furthermore, the fragmentation process during its preparation introduces substantial stress, making its structure highly unstable at high temperatures. When the temperature is too high, the fluidity of the double-sided adhesive changes, causing nanocrystalline fragments to move and altering the internal structure, thus changing its magnetic permeability. This affects heating efficiency and ultimately, the taste. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a high-temperature resistant magnetic material and its preparation method. When the magnetic material prepared by the method of the present invention is applied to electronic cigarettes, it can maintain a small fluctuation in magnetic permeability under high temperature environment, thereby ensuring uniform heating and better taste.

[0007] A first aspect of the present invention provides a method for preparing a high-temperature resistant magnetically conductive material, comprising: sequentially heat-treating and surface-coating a nanocrystalline ribbon to obtain a heat-treated and surface-coated single-layer nanocrystalline ribbon; and subjecting the single-layer nanocrystalline ribbon to the following treatments in any order: i) using the surface coating as an adhesive to bond multiple single-layer nanocrystalline ribbons together to form a composite multilayer structure; ii) performing a crushing treatment to generate cracks; and iii) sequentially passing the ribbon through alternating high-temperature and high-humidity regions and low-temperature regions.

[0008] Specifically, the processing can be carried out in any of the following sequences: 1) using surface adhesive as a binder to bond multiple single-layer nanocrystalline ribbons together to form a composite multilayer structure; the composite multilayer nanocrystalline ribbons are then subjected to a crushing process to induce cracks; the crushed nanocrystalline ribbons are then passed sequentially through alternating high-temperature and high-humidity zones and low-temperature zones; or 2) using surface adhesive as a binder to crush single-layer nanocrystalline ribbons to induce cracks; multiple crushed single-layer nanocrystalline ribbons are then bonded together to form a composite multilayer structure; the composite multilayer nanocrystalline ribbons are then passed sequentially through alternating high-temperature and high-humidity zones and low-temperature zones; or 3) using surface adhesive as a binder to crush single-layer nanocrystalline ribbons to induce cracks; the crushed single-layer nanocrystalline ribbons are then passed sequentially through alternating high-temperature and high-humidity zones and low-temperature zones; multiple single-layer nanocrystalline ribbons subjected to high-temperature, high-humidity, and low-temperature treatments are then bonded together to form a composite multilayer structure. Preferably, the magnetic material obtained by processing in the order of 1) has higher temperature resistance and more stable product performance.

[0009] According to a specific embodiment of the present invention, the temperature of the high temperature and high humidity zone is 80 to 200°C and the humidity is 50 to 90% RH; the temperature of the low temperature zone is -20 to -40°C.

[0010] According to a specific embodiment of the present invention, the number of high temperature and high humidity regions and low temperature regions are the same, ranging from 3 to 10.

[0011] According to a specific embodiment of the present invention, the material passes sequentially along the S-path through alternating high-temperature and high-humidity regions and low-temperature regions, with a dwell time of 1 to 10 minutes in each region. The S-path facilitates complete separation between fragments, avoiding a tangled structure that leads to significant material loss. After being subjected to bending and extreme high and low temperature environments, the structure becomes more stable, thereby ensuring that the magnetic permeability of the magnetic material fluctuates less under high-temperature conditions.

[0012] According to a specific embodiment of the present invention, a nanocrystalline ribbon with a thickness of 15-25 μm and a width of 30-80 mm is selected, wound into a magnetic core, and then subjected to heat treatment. The wound magnetic core is placed in an annealing furnace with a specific atmosphere (vacuum / hydrogen / nitrogen / argon, etc.), the heat treatment temperature is 500-600℃, the heat treatment time is 0.5-3 h, the heating rate is 1-50℃ / min, and the cooling rate is less than 5℃ / min to prevent internal stress generated during cooling. The heat-treated roll is unrolled, and high-temperature resistant PI substrate double-sided adhesive, or high-temperature resistant substrate-free double-sided adhesive, is bonded to one or both surfaces. Preferably, PI substrate double-sided adhesive with better temperature resistance is used for bonding, and the thickness of the double-sided adhesive is 1-15 μm.

[0013] According to a specific embodiment of the present invention, 1 to 10 single-layer nanocrystalline ribbons are bonded together to form a composite multilayer structure.

[0014] According to a specific embodiment of the present invention, the crushing process generates cracks to form multiple fragment units with a size of 0.1–5 mm. Specifically, the roll material with double-sided adhesive is unwound and continuously subjected to roll crushing, resulting in multiple cracks evenly distributed on the unwound nanocrystalline ribbon. By controlling the spacing of the cracks, the size of the fine fragments is changed, thereby increasing the material resistivity, reducing eddy current losses, reducing the heat generation of the nanocrystalline body, and improving heating efficiency. The unwinding process results in better consistency, avoiding the problem of large differences in internal structural changes caused by poor temperature uniformity between the inner and outer rings of the roll material after it has been placed at a set temperature.

[0015] In a second aspect, the present invention provides a high-temperature resistant magnetically conductive material prepared by the aforementioned method.

[0016] A third aspect of the present invention provides an electronic cigarette, comprising an electromagnetic induction heating coil and a magnetically conductive material wound around the surface of the electromagnetic induction heating coil. The magnetically conductive material is the aforementioned high-temperature resistant magnetically conductive material. Specifically, the aforementioned magnetically conductive material can be cut to the required size and wound around the coil.

[0017] The beneficial effects of this invention are as follows:

[0018] The preparation method provided by this invention specifically introduces stress relief treatment in high and low temperature environments, thereby solving the problem of large changes in the permeability of magnetic materials under high temperature environments and improving the high-temperature stability of the product. The preparation method of this invention is simple and can be continuously produced. The resulting magnetic material has the characteristics of high temperature resistance, high permeability, and low loss. It can be arbitrarily cut according to the size of the coupling coil to meet the needs of electronic cigarettes of different sizes. On the one hand, it provides a high permeability channel for coupling heating, improving heating efficiency and uniformity; on the other hand, it prevents the magnetic field lines generated by the alternating magnetic field of the induction coil from interfering with other electronic components, thus playing a shielding role. Attached Figure Description

[0019] Figure 1 It is a single-layer nanocrystalline material; from top to bottom, it consists of release film / double-sided adhesive (without substrate or PI substrate) / nanocrystalline / double-sided adhesive / release film;

[0020] Figure 2 It is a double-layer structured nanocrystalline material; from top to bottom, it consists of release film / double-sided adhesive (without substrate or PI substrate) / nanocrystalline / double-sided adhesive / nanocrystalline / double-sided adhesive / release film;

[0021] Figure 3 Double-sided adhesive for PI substrate; from top to bottom: adhesive / PI substrate / adhesive;

[0022] Figure 4 This is a schematic diagram of the crushing process;

[0023] Figure 5 This is a schematic diagram of the material after it has been broken up.

[0024] Figure 6 This is a schematic diagram of the stress relief process. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] Example 1

[0027] A high-temperature resistant magnetically permeable material, prepared by the following method:

[0028] 1. Preparation and Heat Treatment of Nanocrystalline Ribbons: An alloy with the composition FeCuNbSiB (Fe 70-85%, Cu 0.1-8%, Nb 0.1-5%, Si 5-20%, B 3-10%) was prepared into an amorphous alloy ribbon using a single-roll rapid quenching method. The preferred ribbon thickness was 18 μm (thickness is one of the main factors determining the Q value of the magnetic conductor; the smaller the thickness, the lower the loss), and the ribbon width was 65 mm. Testing showed that its initial crystallization temperature and primary crystallization peak temperature were 515℃ and 535℃, respectively. The obtained ribbon was wound into a magnetic ring with dimensions OD100×ID80×H65 and heat-treated under a nitrogen atmosphere. Specifically, the temperature was increased to 480℃ at 8℃ / min and held for 90 min, then increased to 570℃ at 3℃ / min and held for 60 min, followed by cooling to 150℃ before removal from the furnace.

[0029] 2. Surface Coating: After heat treatment, the strip is opened and bonded to both sides with high-temperature resistant double-sided adhesive on a PI substrate. A 20-50 μm thick release film is applied over the double-sided adhesive, resulting in a total adhesive thickness of 1-10 μm, thus obtaining a single-layer nanocrystalline material, such as... Figure 1 As shown.

[0030] 3. Preparation of composite multilayer structure: After peeling off the release film from one side of the tape with double-sided adhesive, another layer of nanocrystalline tape is adhered. A third layer of PI-based double-sided adhesive is then adhered to the other side of the newly adhered tape, forming a double-layer nanocrystalline material. The structures of the double-layer nanocrystalline material and the PI-based double-sided adhesive are as follows: Figure 2 , 3 As shown.

[0031] 4. Crushing process: The obtained strip is crushed using embossing equipment or roll shearing equipment, such as... Figure 4 As shown, the upper roller is a pressure roller with a specific pattern, and the lower roller is a flat roller. After crushing, the intact nanocrystals exhibit a fragmented appearance, forming fragments of different sizes, such as... Figure 5 As shown; by adjusting the size of the pressure roller and the pressure, the fragment size is controlled to be 0.2mm.

[0032] 5. Stress relief treatment, such as Figure 6 As shown, each square represents a temperature zone. The temperature of odd-numbered zones is set to 150℃ and the humidity to 75%, while the temperature of even-numbered zones is set to -20℃. The S-bend path length of each zone is 10 meters, and the strip feeding speed is 2 meters per minute.

[0033] The nanocrystalline magnetic material prepared in Example 1 was tested and found to have an inductance of 6.1 μH, a Q value of 90, and a permeability of 300 at 100 kHz. After placing this high-temperature resistant magnetic material in an environment of 120°C for 5 hours, its performance was tested again, and the inductance was 6.11 μH, the Q value was 92, and the permeability was 302 at 100 kHz, with very small changes.

[0034] Example 2

[0035] The difference from Example 1 is that the order of the steps after step 2 is different. Steps 4, 3 and 5 are performed in sequence after step 2.

[0036] The nanocrystalline magnetic material prepared in Example 2 was tested and found to have an inductance of 6.1 μH, a Q value of 90, and a permeability of 300 at 100 kHz. After placing this high-temperature resistant magnetic material at 120°C for 5 hours, its performance was tested again, showing an inductance of 6.07 μH, a Q value of 90, and a permeability of 288 at 100 kHz.

[0037] Example 3

[0038] The difference from Example 1 is that the order of the steps after step 2 is different. Steps 4, 5 and 3 are performed in sequence after step 2.

[0039] The nanocrystalline magnetic material prepared in Example 3 was tested and found to have an inductance of 6.1 μH, a Q value of 90, and a permeability of 300 at 100 kHz. After placing this high-temperature resistant magnetic material in an environment of 120°C for 5 hours, its performance was tested again, and the inductance was 6.17 μH, the Q value was 86, and the permeability was 342 at 100 kHz.

[0040] Comparative Example

[0041] The difference from Example 1 is that step 5 is omitted.

[0042] Testing revealed that the nanocrystalline magnetic material prepared in the comparative experiment exhibited an inductance of 6.1 μH, a Q value of 90, and a permeability of 300 at 100 kHz. After placing this high-temperature resistant magnetic material at 120°C for 5 hours, its performance was tested again, showing an inductance of 6.25 μH, a Q value of 84, and a permeability of 386 at 100 kHz, indicating a significant change in performance.

[0043] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-temperature resistant magnetically permeable material, characterized in that, The preparation method includes: The nanocrystalline ribbon was subjected to heat treatment and surface coating in sequence to obtain a single-layer nanocrystalline ribbon with heat treatment and surface coating. The single-layer nanocrystalline ribbon is processed in any order as follows: i) using surface adhesive as a binder to bond multiple single-layer nanocrystalline ribbons together to form a composite multilayer structure; ii) undergoing a crushing process to generate cracks; iii) passing the ribbon through alternating high-temperature and high-humidity zones and low-temperature zones.

2. The preparation method according to claim 1, characterized in that, The single-layer nanocrystalline ribbon is processed in the following manner: Using surface adhesive as a binder, multiple single-layer nanocrystalline ribbons are bonded together to form a composite multilayer structure; The composite multilayer nanocrystalline ribbon is broken to induce cracks. The nanocrystalline ribbon, which has developed cracks after being crushed, is passed sequentially through alternating high-temperature and high-humidity zones and low-temperature zones.

3. The preparation method according to claim 1 or 2, characterized in that, The temperature in the high-temperature and high-humidity zone is 80–200℃, and the humidity is 50–90%RH; the temperature in the low-temperature zone is -20–-40℃.

4. The preparation method according to claim 1 or 2, characterized in that, The number of high-temperature and high-humidity zones and low-temperature zones are the same, ranging from 3 to 10.

5. The method according to claim 1 or 2, characterized in that, The device is made to pass through alternating high-temperature and high-humidity zones and low-temperature zones along the S path, with a dwell time of 1 to 10 minutes in each zone.

6. The preparation method according to claim 1 or 2, characterized in that, The heat treatment is carried out in an oxygen-free environment, the temperature of the heat treatment is 500-600℃, and the heat treatment time is 0.5-3h; the surface coating is to attach high-temperature resistant PI substrate double-sided adhesive or high-temperature resistant substrate-free double-sided adhesive to one or both sides of the heat-treated nanocrystalline ribbon; preferably, the double-sided adhesive is high-temperature resistant PI substrate double-sided adhesive with a thickness of 1-15μm.

7. The preparation method according to claim 1 or 2, characterized in that, One to ten single-layer nanocrystalline ribbons are bonded together to form a composite multilayer structure.

8. The preparation method according to claim 1 or 2, characterized in that, The crushing process creates cracks to form multiple fragment units with a size of 0.1 to 5 mm.

9. The high-temperature resistant magnetically conductive material prepared by the preparation method according to claims 1 to 8.

10. An electronic cigarette, comprising an electromagnetic induction heating coil and a magnetically conductive material wound around the surface of the electromagnetic induction heating coil, characterized in that, The magnetically conductive material is the high-temperature resistant magnetically conductive material as described in claim 9.

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