Magnetic conductive thermosetting adhesive, preparation method thereof, and sound production device and magnetic circuit system thereof

Abstract

This application belongs to the field of electroacoustic technology, and specifically relates to a magnetic thermosetting adhesive, its preparation method, and a sound-generating device and its magnetic circuit system. The magnetic thermosetting adhesive comprises a thermosetting adhesive and a magnetic filler. The magnetic filler has a particle size of 0.1 μm to 10 μm and a specific saturation magnetization of 50 emu / g to 250 emu / g. The magnetic filler comprises a magnetic material, including at least one of iron, nickel, and cobalt, and the magnetic material accounts for ≥90% of the total mass of the magnetic filler. The magnetic thermosetting adhesive provided by this application combines excellent magnetic permeability with structural bonding performance, effectively improving the magnetic flux density of the sound-generating device's magnetic circuit, significantly enhancing the overall magnetic permeability of the magnetic circuit, and improving the acoustic performance of the sound-generating device. Simultaneously, the resin properties compensate for the negative impact of the addition of the magnetic filler on the bonding interface, ensuring reliable bonding of the magnetic circuit components and a safety margin for drop resistance and environmental storage during product use.

Description

Technical Field

[0001] This application belongs to the field of electroacoustic technology, and specifically relates to a magnetic thermosetting adhesive, its preparation method, a sound-generating device, and its magnetic circuit system. Background Technology

[0002] In the field of loudspeaker design and manufacturing, the magnetic conductivity of the magnetic circuit system directly determines the overall acoustic performance of the speaker. Generally, the better the magnetic conductivity of the magnetic circuit, the more guaranteed the loudness and sound purity of the speaker's output. Therefore, the industry has placed higher design requirements on the magnetic conductivity of magnetic circuit components such as magnets, magnetic yokes, and magnetic plates.

[0003] As electronic products continue to evolve towards thinner and smaller designs, bonding and fixing processes have become the mainstream connection method for speaker magnetic circuit components due to their advantages of small space occupation and simple assembly process. Currently, the industry generally uses epoxy resin adhesives to bond and fix the various components of the magnetic circuit. However, when conventional epoxy adhesives are applied to the bonding interface of the magnetic circuit, they cannot generate gain for the magnetic flux transmission in the magnetic circuit, and may even disrupt the continuity of magnetic flux transmission, introduce additional magnetic resistance, and cause magnetic flux loss, thus restricting further improvement of the overall magnetic conductivity of the magnetic circuit and the acoustic performance of the speaker.

[0004] Therefore, existing loudspeakers and the adhesive materials used with them still need improvement. Summary of the Invention

[0005] The purpose of this application is to provide a magnetically conductive thermosetting adhesive and its preparation method, as well as a sound-generating device and its magnetic circuit system. The magnetically conductive thermosetting adhesive provided by this application has both excellent magnetic permeability and structural bonding performance, which can effectively improve the magnetic flux density of the magnetic circuit of the sound-generating device; significantly enhance the overall magnetic permeability of the magnetic circuit and improve the acoustic performance of the sound-generating device; at the same time, the resin properties compensate for the negative impact of the addition of magnetically conductive fillers on the bonding interface, ensuring reliable bonding of magnetic circuit components and a safety margin for drop resistance / environmental storage in product use.

[0006] The first aspect of this application provides a magnetic thermosetting adhesive, comprising a thermosetting adhesive and a magnetic filler dispersed within the thermosetting adhesive. The magnetic filler has a particle size of 0.1 μm to 10 μm and a specific saturation magnetization of 50 emu / g to 250 emu / g. The magnetic filler comprises a magnetic material, which includes at least one of iron, nickel, and cobalt, and the magnetic material accounts for ≥90% of the total mass of the magnetic filler.

[0007] In some embodiments of this application, the magnetic material comprises iron, and the mass percentage of iron in the magnetic filler is ≥30%.

[0008] In some embodiments of this application, the magnetic filler further includes auxiliary materials, which include at least one of silicon, phosphorus, chromium, and aluminum; the auxiliary materials account for ≤10% of the total mass of the magnetic filler.

[0009] In some embodiments of this application, the thermosetting adhesive has a Shore hardness ≥ D60 and a tensile strength ≥ 25 MPa.

[0010] In some embodiments of this application, the thermosetting adhesive includes at least one of epoxy thermosetting adhesive, acrylic thermosetting adhesive, and anaerobic thermosetting adhesive.

[0011] In some embodiments of this application, the magnetic thermosetting adhesive further includes at least one of an antioxidant and an anti-settling agent.

[0012] In some embodiments of this application, the anti-settling agent comprises nano-sized hydrophobic silica.

[0013] In some embodiments of this application, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 4010.

[0014] In some embodiments of this application, the magnetically conductive thermosetting adhesive comprises the following components in parts by weight: 50-80 parts thermosetting adhesive, 20-50 parts magnetic filler, 1-5 parts antioxidant, and 1-5 parts anti-settling agent.

[0015] In some embodiments of this application, the tensile strength of the magnetic thermosetting adhesive is ≥20 MPa.

[0016] In some embodiments of this application, the specific saturation magnetization of the magnetic thermosetting adhesive is 10 emu / g to 200 emu / g.

[0017] The second aspect of this application also provides a method for preparing the magnetic thermosetting adhesive described in the first aspect of this application, comprising the following steps: obtaining a magnetic filler and a thermosetting adhesive; the magnetic filler has a particle size of 0.1 μm to 10 μm and a specific saturation magnetization of 50 emu / g to 250 emu / g; mixing and stirring the magnetic filler and the thermosetting adhesive in a desired ratio to obtain the magnetic thermosetting adhesive.

[0018] A third aspect of this application also provides a magnetic circuit system for a sound-generating device, comprising a magnetic yoke and a magnetic circuit assembly disposed on one side of the magnetic yoke. The magnetic circuit assembly includes a magnet and a magnetic plate, and the magnetic yoke, the magnet, and the magnetic plate are sequentially stacked along a first direction. The magnetic yoke and the magnet, and / or the magnet and the magnetic plate, are provided with the magnetic thermosetting adhesive described in the first aspect of this application, or with a magnetic thermosetting adhesive prepared using the preparation method described in the second aspect of this application.

[0019] In some embodiments of this application, the magnet includes a central magnet and side magnets spaced apart, and the magnetic guide plate includes a central magnetic guide plate and side magnetic guide plates. The central magnet and the central magnetic guide plate constitute a central magnetic part, and the side magnets and the side magnetic guide plates constitute a side magnetic part. The magnetic yoke, the central magnet, and the central magnetic guide plate are sequentially stacked along a first direction, and the central magnet and the magnetic yoke, and / or the central magnet and the central magnetic guide plate, are bonded together by the magnetic thermosetting adhesive.

[0020] In some embodiments of this application, the magnetic yoke, the side magnet, and the side magnetic plate are stacked sequentially along a first direction, and the side magnet and the magnetic yoke and / or the side magnet and the side magnetic plate are bonded together by the magnetic thermosetting adhesive.

[0021] The fourth aspect of this application also provides a sound-generating device, which includes the magnetic circuit system for the sound-generating device described in the third aspect of this application.

[0022] The magnetic thermosetting adhesive provided in this application includes a thermosetting adhesive and a magnetic filler. The magnetic material in the magnetic filler includes at least one of iron, nickel, and cobalt, and the magnetic material accounts for ≥90% of the total mass of the magnetic filler. This gives the magnetic thermosetting adhesive excellent magnetic permeability, which can effectively increase the magnetic flux density of the magnetic circuit of the sound-generating device, significantly enhance the overall magnetic permeability of the magnetic circuit, and improve the acoustic performance of the sound-generating device. At the same time, the resin properties compensate for the negative impact of the addition of the magnetic filler on the bonding interface, ensuring reliable bonding of the magnetic circuit components and a safety margin for drop resistance and environmental storage in product use.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a sound-generating device according to some embodiments of this application.

[0026] Explanation of reference numerals in the attached figures: 100 - Sound-generating device; 10-Housing; 20-Diaphragm assembly; 30-Magnetic yoke; 40-Center magnet; 50-Side magnet; 60-Center magnetic plate; 70-Side magnetic plate; 80-Magnetic thermosetting adhesive; 90-Voice coil. Detailed Implementation

[0027] Exemplary embodiments of this application will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of this application and to fully convey the scope of this application to those skilled in the art.

[0028] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0029] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0030] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0031] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0032] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0033] The first aspect of this application provides a magnetic thermosetting adhesive, which includes a thermosetting adhesive and a magnetic filler dispersed within the thermosetting adhesive. The magnetic filler has a particle size of 0.1 μm to 10 μm and a specific saturation magnetization of 50 emu / g to 250 emu / g. The magnetic filler includes a magnetic material, which includes at least one of iron, nickel, and cobalt, and the magnetic material accounts for ≥90% of the total mass of the magnetic filler.

[0034] In the embodiments of this application, the magnetic filler is uniformly dispersed in a thermosetting adhesive system. The resulting magnetic thermosetting adhesive not only achieves reliable mechanical bonding and fixation between the magnetic circuit components of the sound-generating device, but also allows magnetic lines of force to smoothly penetrate the adhesive layer, effectively reducing the magnetic resistance between the interfaces of components such as magnets and magnetic yokes, and increasing the magnetic flux density of the sound-generating device (e.g., a loudspeaker). Simultaneously, the insulating thermosetting matrix encapsulates the magnetic filler. When an alternating magnetic field passes through the adhesive layer, eddy currents are confined within individual tiny filler particles, thereby reducing eddy current losses and improving the quality factor. With the same input power, this effectively increases the output loudness of the sound-generating device and optimizes low-frequency sound effects, resulting in better bass performance, thus significantly improving the acoustic performance of the sound-generating device.

[0035] The magnetic filler provided in this embodiment has a particle size of 0.1 μm to 10 μm. It is understood that when the particle size of the magnetic filler is too small, less than 0.1 μm, the large specific surface area of ​​the filler makes it difficult for the adhesive to wet, resulting in large hard agglomerates. This affects the rheology and coating process of the adhesive, making it difficult to form a uniform film and hindering the construction of a continuous magnetic path. Conversely, when the particle size of the magnetic filler is too large, greater than 10 μm, it easily causes uneven adhesive layer thickness, increases the assembly gap of magnetic circuit components, disrupts the continuity of magnetic flux transmission, and is difficult to be fully coated by the insulating thermosetting matrix, easily forming conductive connection paths and exacerbating eddy current losses under alternating magnetic fields. For example, the particle size of the magnetic filler can be one of 0.1 μm, 0.2 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm or any value that satisfies the above range.

[0036] The specific saturation magnetization of the magnetic filler provided in this application embodiment is 50 emu / g to 250 emu / g. It is understood that when the magnetic filler is pure nickel powder, the specific saturation magnetization is approximately 50 emu / g. After mixing it with a binder in a certain proportion, its own magnetic carrying capacity is insufficient, the magnetization response is weak, and it cannot effectively converge and disperse magnetic lines of force, making it difficult to reduce the magnetic reluctance at the magnetic circuit interface and achieve the effect of increasing the magnetic flux density of the magnetic circuit. The specific saturation magnetization of the ferromagnetic magnetic filler is approximately 250 emu / g. Therefore, this application requires the addition of ferromagnetic powder to account for ≥30% to ensure the magnetism of the magnetic thermosetting binder in different mixing proportions and meet the product's requirements for high magnetic permeability and low loss. For example, the specific saturation magnetization of the magnetic filler can be one of 50 emu / g, 60 emu / g, 70 emu / g, 80 emu / g, 90 emu / g, 100 emu / g, 110 emu / g, 120 emu / g, 130 emu / g, 140 emu / g, 150 emu / g, 160 emu / g, 170 emu / g, 180 emu / g, 190 emu / g, 200 emu / g, 210 emu / g, 220 emu / g, 230 emu / g, 240 emu / g, or 250 emu / g, or any value satisfying the above range.

[0037] The magnetic material provided in the embodiments of this application includes at least one of iron, nickel, and cobalt. For example, the magnetic material can be iron, nickel, or cobalt, or it can be any combination of two or three of iron, nickel, and cobalt.

[0038] In this embodiment, the magnetic material accounts for ≥90% of the total mass of the magnetically conductive filler. This ensures that the magnetically conductive filler possesses sufficient magnetic response and magnetic flux conduction capabilities, effectively constructing a continuous and stable magnetic network within the adhesive system. This significantly reduces the magnetic resistance at the magnetic circuit bonding interface, increases the magnetic flux density, and helps confine eddy currents within individual particles, suppressing eddy current losses and ensuring the sound-generating device has a high quality factor and good sound loudness and low-frequency performance. Conversely, if the mass percentage of the magnetic material is less than 90%, the proportion of non-magnetic components in the magnetically conductive filler is too high, potentially leading to a significant decrease in overall permeability and magnetization performance. This makes it difficult to form an efficient and continuous magnetic flux transmission path, increases the magnetic resistance at the magnetic circuit interface, and fails to achieve the desired magnetic flux gain effect. For example, the mass percentage of the magnetic material in the total mass of the magnetically conductive filler can be one of 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, or 99.5%, or any value within the aforementioned range.

[0039] By selecting magnetic materials and setting their mass ratio appropriately, and by adjusting the particle size and specific saturation magnetization of the magnetic filler within the aforementioned range, it is possible to further increase the magnetic conductivity of the magnetic circuit components and improve the acoustic performance of the sound-generating device while ensuring the bonding performance and product reliability of the magnetic thermosetting adhesive.

[0040] In the embodiments of this application, to ensure that the magnetic thermosetting adhesive still possesses high magnetic permeability and specific saturation magnetization even with a low proportion of magnetic filler, iron, an element with superior magnetic permeability, is used as the main filler component, and its content is not less than 30% of the total mass of the filler. In some embodiments of this application, the magnetic material includes iron, and the mass percentage of iron in the magnetic filler is ≥30%. Exemplarily, the mass percentage of iron in the magnetic filler can be one of 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 99%, or any value satisfying the above range.

[0041] In embodiments of this application, in order to further reduce magnetic loss, improve corrosion resistance, and improve processability, the magnetic filler also includes auxiliary materials. In some embodiments of this application, the auxiliary materials include at least one of silicon, phosphorus, chromium, and aluminum.

[0042] In some embodiments of this application, the auxiliary materials account for ≤10% of the total mass of the magnetic filler. This helps to further reduce magnetic loss, improve corrosion resistance, and enhance processability. However, when the mass percentage of auxiliary materials exceeds 10%, the excessive proportion of non-magnetic auxiliary components significantly dilutes the overall permeability and magnetization performance of the magnetic filler, disrupts the continuous magnetic flux conduction network within the system, and causes an increase in magnetic reluctance at the magnetic circuit interface and aggravated magnetic flux loss. Furthermore, excessive auxiliary materials can negatively impact the curing characteristics and mechanical bond strength of the adhesive. For example, the mass percentage of auxiliary materials in the total mass of the magnetic filler can be one of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, or 10%, or any value within the aforementioned range.

[0043] In some embodiments of this application, the Shore hardness of the thermosetting adhesive is ≥D60. Exemplarily, the Shore hardness of the thermosetting adhesive may be D60, D62, D64, D65, D66, D68, D70, D76, D80, D82, D85, etc.

[0044] In some embodiments of this application, the tensile strength of the thermosetting adhesive is ≥25 MPa. Exemplarily, the tensile strength of the thermosetting adhesive may be 25 MPa, 26 MPa, 27 MPa, 28 MPa, 30 MPa, 33 MPa, 36 MPa, etc.

[0045] In some embodiments of this application, the thermosetting adhesive includes at least one of epoxy thermosetting adhesive, acrylic thermosetting adhesive, and anaerobic thermosetting adhesive. This allows the thermosetting adhesive to both meet the structural bonding and fixing requirements of the magnetic circuit components of the sound-generating device, and to isolate filler particles, suppress eddy current losses, and adapt to the requirements for stable magnetic flux conduction in the magnetic circuit.

[0046] Specifically, acrylic thermosetting adhesives have higher resin elongation at break, making them suitable for workstations with larger bonding areas to meet the drop requirements of products; epoxy thermosetting adhesives have higher modulus and a denser oxygen-free polymerization structure, making them suitable for bonding surfaces with narrower surfaces or for edge magnet locations with lateral attraction, improving the reliability of products in environments such as salt spray / high temperature and high humidity.

[0047] In some embodiments of this application, the thermosetting adhesive is an epoxy thermosetting adhesive, which comprises the following components in parts by weight: 100 parts of bisphenol A type epoxy resin, 64 parts of curing agent, 3 parts of accelerator, 1 part of thixotropic agent, and 1 part of antioxidant.

[0048] In embodiments of this application, the curing agent includes one of pentaerythritol tetra(3-mercaptopropionate), trimethylolpropane tri(3-mercaptopropionate), and ethoxylated trimethylolpropane tri(3-mercaptopropionate).

[0049] In the embodiments of this application, the accelerator includes one of DMP-30, triethylamine, and dimethylbenzylamine.

[0050] In embodiments of this application, the thixotropic agent comprises nanoscale fumed silica.

[0051] In embodiments of this application, the antioxidant includes antioxidant 1010.

[0052] In some embodiments of this application, the thermosetting adhesive is an acrylic thermosetting adhesive, which comprises the following components in parts by weight: 70 parts of acrylate oligomer, 30 parts of acrylate monomer, 5 parts of thermal initiator, 0.5 parts of curing agent, 1 part of thixotropic agent, and 1 part of antioxidant.

[0053] In embodiments of this application, the acrylate oligomer includes polyurethane acrylate oligomers.

[0054] In embodiments of this application, the acrylate monomers include a mixture of 4-hexanediol morpholine, hexanediol diacrylate, acrylic acid, and hydroxyethyl methacrylate.

[0055] In embodiments of this application, the thermal initiator includes at least one of azobisisobutyronitrile, cumene hydroperoxide, and benzoyl peroxide.

[0056] In embodiments of this application, the antioxidant includes antioxidant 1010.

[0057] In embodiments of this application, the thixotropic agent comprises nanoscale fumed silica.

[0058] In the embodiments of this application, the curing agent is an acrylate monomer carrying special functional groups in the resin, which undergoes a chemical reaction during the reaction process to achieve further cross-linking of the resin network.

[0059] In the embodiments of this application, the small bonding area of ​​the edge magnets makes them more prone to bonding failure and detachment after environmental reliability testing. Epoxy thermosetting adhesives, which provide magnetic conductivity, have high modulus and are oxygen-free, allowing for curing of excess adhesive at the bonding edges. Used for edge magnets with smaller bonding areas, this improves the product's environmental reliability against salt spray, high temperature, and high humidity. The heavy center magnet is more susceptible to failure in drop tests. Acrylic thermosetting adhesives, which provide magnetic conductivity, have high elongation at break and are used for bonding the heavier center magnet, improving the product's drop resistance. This bonding method ensures improved magnetic conductivity while compensating for the loss of bonding strength and environmental reliability caused by the addition of magnetic fillers through the properties of the resin.

[0060] In some embodiments of this application, the magnetic thermosetting adhesive further includes at least one of an antioxidant and an anti-settling agent.

[0061] In embodiments of this application, the magnetic thermosetting adhesive includes a thermosetting adhesive, a magnetic filler, and at least one of an antioxidant and an antisettling agent.

[0062] Specifically, antioxidants can effectively delay the oxidative aging of magnetic fillers and adhesive matrices under long-term exposure to heat, moisture, and alternating magnetic fields, preventing the magnetic fillers from oxidizing and deteriorating, thus avoiding magnetic property attenuation and ensuring the structural stability of the adhesive system and the long-term durability of the magnetic circuit's permeability. Anti-settling agents can improve the suspension and dispersion of magnetic fillers in the adhesive system, inhibiting sedimentation, agglomeration, and stratification during storage and settling, ensuring uniform distribution of fillers within the adhesive. After curing, the magnetic and mechanical properties of the adhesive layer are consistent throughout, facilitating the formation of continuous and stable magnetic pathways, reducing magnetic reluctance and flux loss at the magnetic circuit interface, while ensuring uniformity of the adhesive application process and bonding precision of the magnetic circuit components, thereby improving the operational stability and long-term acoustic performance of the sound-generating device's magnetic circuit system.

[0063] In some embodiments of this application, the anti-settling agent includes nano-sized hydrophobic silica, which can improve the dispersibility of magnetic fillers in thermosetting adhesives.

[0064] In some embodiments of this application, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 4010.

[0065] In some embodiments of this application, the magnetically conductive thermosetting adhesive comprises the following components in parts by weight: 50-80 parts thermosetting adhesive, 20-50 parts magnetic filler, 1-5 parts antioxidant, and 1-5 parts anti-settling agent.

[0066] The thermosetting adhesive provided in the embodiments of this application can be one of 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, 62 parts, 65 parts, 68 parts, 70 parts, 72 parts, 75 parts, 78 parts, or 80 parts by weight, or any value that meets the above range.

[0067] The weight percentage of the magnetic filler provided in the embodiments of this application can be one of 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, or 50 parts, or any value that meets the above range.

[0068] The antioxidant provided in the embodiments of this application can be one of 1 part, 2 parts, 3 parts, 4 parts, or 5 parts by weight, or any value that meets the above range.

[0069] The weight percentage of the anti-settling agent provided in the embodiments of this application can be one of 1 part, 2 parts, 3 parts, 4 parts, or 5 parts, or any value that meets the above range.

[0070] By setting the components of the above-mentioned magnetic thermosetting adhesive and selecting their weight proportions within the above range, it is helpful to obtain a magnetic thermosetting adhesive that can not only achieve reliable mechanical bonding and fixation between the magnetic circuit components of the sound-generating device, but also allow magnetic lines of force to smoothly penetrate the adhesive layer, effectively reducing the magnetic resistance between the interface of the magnet and the magnetic yoke, and increasing the magnetic flux density of the magnetic circuit of the sound-generating device.

[0071] In some embodiments of this application, the tensile strength of the magnetic thermosetting adhesive is ≥20 MPa. It is understood that if the tensile strength of the magnetic thermosetting adhesive is less than 20 MPa, the adhesive's bonding and holding power is insufficient, and it is prone to loosening, delamination, and cracking under the influence of vibration and environmental temperature changes, thus damaging the integrity of the magnetic circuit structure and affecting acoustic performance. Exemplarily, the tensile strength of the magnetic thermosetting adhesive can be one of 20 MPa, 22 MPa, 24 MPa, 25 MPa, 26 MPa, 27 MPa, 28 MPa, or 30 MPa, or any value satisfying the above range.

[0072] In some embodiments of this application, the specific saturation magnetization of the magnetic thermosetting adhesive is 10 emu / g to 200 emu / g. It is understood that when pure nickel powder is compounded with the adhesive in a very low proportion, the specific saturation magnetization of the magnetic thermosetting adhesive will be less than 10 emu / g. At this point, the overall magnetic response and magnetic permeability of the adhesive are too weak, making it impossible to effectively construct a magnetic flux conduction path and achieve the effect of reducing magnetic resistance and increasing magnetic flux density. Conversely, when the proportion of pure iron powder added to the adhesive exceeds 80 wt%, the specific saturation magnetization of the magnetic thermosetting adhesive is higher than 200 emu / g. However, at this point, the viscosity of the magnetic thermosetting adhesive is too high, making normal dispensing operation impossible in actual application stations. For example, the specific saturation magnetization of the magnetic thermosetting adhesive can be one of 10 emu / g, 20 emu / g, 30 emu / g, 40 emu / g, 50 emu / g, 60 emu / g, 70 emu / g, 80 emu / g, 90 emu / g, 100 emu / g, 110 emu / g, 120 emu / g, 130 emu / g, 140 emu / g, 150 emu / g, 160 emu / g, 170 emu / g, 180 emu / g, 190 emu / g, 200 emu / g, or any value satisfying the above range.

[0073] By setting the tensile strength and specific saturation magnetization of the magnetic thermosetting adhesive within the aforementioned range, it can possess excellent mechanical bonding properties, firmly bond the various components of the magnetic circuit of the sound-generating device, resist the stress caused by vibration and temperature changes during use, and ensure the long-term stability and non-deformation of the magnetic circuit structure. At the same time, it has the magnetization capability to adapt to the working requirements of the magnetic circuit, effectively guide magnetic lines of force, reduce the magnetic resistance of the bonding interface, increase the magnetic flux density of the magnetic circuit and suppress eddy current loss, thus ensuring the loudness and low-frequency sound quality of the sound-generating device.

[0074] The second aspect of this application provides a method for preparing a magnetically conductive thermosetting adhesive, thereby obtaining the magnetically conductive thermosetting adhesive described in the first aspect of this application.

[0075] In some embodiments of this application, the preparation method of the magnetic thermosetting adhesive is mainly carried out according to the following steps.

[0076] (1) Obtain magnetic filler and thermosetting adhesive.

[0077] In the embodiments of this application, the magnetic filler is filtered and screened to select magnetic fillers within the target particle size range.

[0078] In some embodiments of this application, the particle size of the magnetic filler is 0.1 μm to 10 μm. Exemplarily, the particle size of the magnetic filler can be one of 0.1 μm, 0.2 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm, or any value satisfying the above range.

[0079] In some embodiments of this application, the specific saturation magnetization of the magnetic filler is 50 emu / g to 250 emu / g. Exemplarily, the specific saturation magnetization of the magnetic filler can be one of 50 emu / g, 60 emu / g, 70 emu / g, 80 emu / g, 90 emu / g, 100 emu / g, 110 emu / g, 120 emu / g, 130 emu / g, 140 emu / g, 150 emu / g, 160 emu / g, 170 emu / g, 180 emu / g, 190 emu / g, 200 emu / g, 210 emu / g, 220 emu / g, 230 emu / g, 240 emu / g, or 250 emu / g, or any value satisfying the above range.

[0080] (2) Mix the magnetic filler and thermosetting adhesive in the required proportion, let stand and fill, and then degas to obtain the magnetic thermosetting adhesive.

[0081] In the embodiments of this application, the prepared magnetic thermosetting adhesive needs to be stored at -20°C away from light to ensure that the adhesive particle size is ≤50 μm.

[0082] In some embodiments of this application, the preparation method of the magnetic thermosetting adhesive is mainly carried out according to the following steps.

[0083] (1) Obtain magnetic filler, thermosetting adhesive, antioxidant and antisettling agent.

[0084] In the embodiments of this application, the magnetic filler is filtered and screened to select magnetic fillers within the target particle size range.

[0085] In some embodiments of this application, the particle size of the magnetic filler is 0.1 μm to 10 μm. Exemplarily, the particle size of the magnetic filler can be one of 0.1 μm, 0.2 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm, or any value satisfying the above range.

[0086] In some embodiments of this application, the specific saturation magnetization of the magnetic filler is 50 emu / g to 250 emu / g. Exemplarily, the specific saturation magnetization of the magnetic filler can be one of 50 emu / g, 60 emu / g, 70 emu / g, 80 emu / g, 90 emu / g, 100 emu / g, 110 emu / g, 120 emu / g, 130 emu / g, 140 emu / g, 150 emu / g, 160 emu / g, 170 emu / g, 180 emu / g, 190 emu / g, 200 emu / g, 210 emu / g, 220 emu / g, 230 emu / g, 240 emu / g, or 250 emu / g, or any value satisfying the above range.

[0087] In some embodiments of this application, the anti-settling agent includes nano-sized hydrophobic silica.

[0088] In some embodiments of this application, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 4010.

[0089] (2) Mix the magnetic filler, thermosetting adhesive, antioxidant and anti-settling agent in the required proportion, let stand and fill, and then degas to obtain the magnetic thermosetting adhesive.

[0090] In the embodiments of this application, the prepared magnetic thermosetting adhesive needs to be stored at -20°C away from light to ensure that the particle size of the magnetic thermosetting adhesive is ≤50 μm.

[0091] It is worth mentioning that, in the embodiments of this application, the particle size of the magnetically conductive thermosetting adhesive is ≤50 μm and not 0. In some embodiments of this application, the particle size of the magnetically conductive thermosetting adhesive is 15 μm to 50 μm. Exemplarily, the particle size of the magnetically conductive thermosetting adhesive can be one of 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm or any value satisfying the above range.

[0092] A third aspect of this application provides a magnetic circuit system for a sound-generating device, combined with... Figure 1 The sound-generating device 100 includes a housing 10 and a vibration system and a magnetic circuit system disposed inside the housing 10. The vibration system includes a diaphragm assembly 20 and a voice coil 90; the magnetic circuit system includes a magnetic yoke 30 and a magnetic circuit assembly disposed on one side of the magnetic yoke 30, the magnetic circuit assembly including a magnet and a magnetic plate, the magnetic yoke, magnet, and magnetic plate being sequentially stacked along a first direction; wherein, a magnetically conductive thermosetting adhesive 80 as described in the first aspect of this application is disposed between the magnetically conductive yoke and the magnet and / or between the magnet and the magnetic plate, or a magnetically conductive thermosetting adhesive 80 prepared using the preparation method described in the second aspect of this application is disposed.

[0093] In some embodiments of this application, the magnet includes a central magnet 40 and a side magnet 50 spaced apart, and the magnetic guide plate includes a central magnetic guide plate 60 and a side magnetic guide plate 70. The central magnet 40 and the central magnetic guide plate 60 constitute a central magnetic part, and the side magnet 50 and the side magnetic guide plate 70 constitute a side magnetic part. The magnetic yoke 30, the central magnet 40 and the central magnetic guide plate 60 are stacked sequentially along a first direction, and the central magnet 40 and the magnetic yoke 30 and / or the central magnet 40 and the central magnetic guide plate 60 are bonded together by a magnetic thermosetting adhesive 80.

[0094] In some embodiments of this application, the magnetic yoke 30, the side magnet 50 and the side magnetic plate 70 are stacked sequentially along a first direction, and the side magnet 50 and the magnetic yoke 30 and / or the side magnet 50 and the side magnetic plate 70 are bonded together by a magnetic thermosetting adhesive 80.

[0095] The fourth aspect of this application also provides a sound-generating device, which includes the magnetic circuit system for the sound-generating device described in the third aspect of this application.

[0096] In embodiments of this application, the sound-generating device may be a miniature loudspeaker.

[0097] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art to which this application pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are all conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained through commercial purchase or by existing methods; the amounts of experimental reagents used are, unless otherwise specified, the amounts used in conventional experimental operations; and the experimental methods used are, unless otherwise specified, conventional methods. It should be further noted that the following descriptions are merely exemplary and not intended to limit the scope of this application. Moreover, the comparative examples below are selected to compare with the technical solutions of this application to demonstrate the advancement of the technical solutions of this application, and do not necessarily represent prior art in this technical field.

[0098] Example 1 This embodiment 1 provides a magnetic thermosetting adhesive and a miniature loudspeaker using the magnetic thermosetting adhesive. The magnetic thermosetting adhesive is used to bond the center magnet or side magnet of the miniature loudspeaker. The magnetic thermosetting adhesive includes the following components by weight: 50 parts thermosetting adhesive, 50 parts iron-nickel alloy magnetic filler, 1 part antioxidant, and 1 part anti-settling agent.

[0099] The iron-nickel alloy magnetic filler has a particle size of 5 μm and a specific saturation magnetization of 150 emu / g. The iron-nickel alloy magnetic filler contains 50 wt% iron, 45 wt% nickel, and 5 wt% silicon and phosphorus. The anti-settling agent is nano-sized fumed silica, and the antioxidant is antioxidant 1010.

[0100] The thermosetting adhesive is an epoxy thermosetting adhesive, comprising the following components by weight: 100 parts of bisphenol A type epoxy resin, 65 parts of curing agent, 3 parts of accelerator, 1 part of thixotropic agent, and 1 part of antioxidant; wherein the curing agent is pentaerythritol tetra(3-mercaptopropionate); the accelerator is 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30); the thixotropic agent is nano-sized fumed silica; and the antioxidant is antioxidant 1010.

[0101] The preparation method of this magnetically conductive thermosetting adhesive includes the following steps: S1: Add epoxy resin, curing agent, accelerator, thixotropic agent, and antioxidant according to the specified ratio, mix and stir, allow to stand, fill, and degas to obtain an epoxy thermosetting adhesive. Store the prepared epoxy thermosetting adhesive at -20℃ away from light. The particle size of the epoxy thermosetting adhesive is ≤50 μm and not 0.

[0102] S2: The iron-nickel alloy magnetic filler is filtered and screened to ensure that the powder particle size is 5 μm.

[0103] S3: Add epoxy thermosetting adhesive, iron-nickel alloy magnetic filler, antioxidant, and anti-settling agent according to the formula ratio, mix and stir, let stand and fill, and then degas to obtain magnetic thermosetting adhesive. Store the prepared magnetic thermosetting adhesive at -20℃ in the dark. The particle size of the magnetic thermosetting adhesive is ≤50 μm and not 0.

[0104] Example 2 This embodiment 2 discloses a magnetic thermosetting adhesive and a miniature loudspeaker using the magnetic thermosetting adhesive. The magnetic thermosetting adhesive is used to bond the center magnet or side magnet of the miniature loudspeaker. The magnetic thermosetting adhesive includes the following components by weight: 50 parts thermosetting adhesive, 50 parts iron-nickel alloy magnetic filler, 1 part antioxidant, and 1 part anti-settling agent.

[0105] The iron-nickel alloy magnetic filler has a particle size of 5 μm and a specific saturation magnetization of 150 emu / g. The iron-nickel alloy magnetic filler contains 50 wt% iron, 45 wt% nickel, and 5 wt% silicon and phosphorus. The anti-settling agent is nano-sized fumed silica, and the antioxidant is antioxidant 1010.

[0106] The thermosetting adhesive is an acrylic thermosetting adhesive, comprising the following components by weight: 70 parts acrylate oligomer, 30 parts acrylate monomer, 5 parts thermal initiator, 0.5 parts curing agent, 1 part thixotropic agent, and 1 part antioxidant; wherein, the acrylate oligomer is a polyurethane acrylate oligomer; the acrylate monomer is a mixture of 4-benzoylmorpholine, hexanediol diacrylate, acrylic acid, and hydroxyethyl methacrylate; the thermal initiator is a mixture of azobisisobutyronitrile, cumene hydroperoxide, and benzoyl peroxide; the antioxidant is antioxidant 1010; the thixotropic agent is nano-sized fumed silica; and the curing agent is an acrylate monomer carrying special functional groups in the resin, which undergoes a chemical reaction during the reaction process to achieve further cross-linking of the resin network.

[0107] The preparation method of this magnetically conductive thermosetting adhesive includes the following steps: S1: Add acrylate oligomer, acrylate monomer, thermal initiator, curing agent, thixotropic agent, and antioxidant according to the formula ratio, mix and stir, allow to stand, fill and degas to obtain acrylic thermosetting adhesive. Store the prepared acrylic thermosetting adhesive at -20℃ in the dark. The particle size of the acrylic thermosetting adhesive is ≤50 μm and not 0.

[0108] S2: The iron-nickel alloy magnetic filler is filtered and screened to ensure that the powder particle size is 5 μm.

[0109] S3: Add acrylic thermosetting adhesive, iron-nickel alloy magnetic filler, antioxidant, and anti-settling agent according to the formula ratio, mix and stir, let stand and fill, and then degas to obtain magnetic thermosetting adhesive. Store the prepared magnetic thermosetting adhesive at -20℃ away from light. The particle size of the magnetic thermosetting adhesive is ≤50 μm.

[0110] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that no iron-nickel alloy magnetic filler was added in Comparative Example 1, and the epoxy thermosetting adhesive in Example 1 was used directly.

[0111] Comparative Example 2 The only difference between Comparative Example 2 and Example 2 is that no iron-nickel alloy magnetic filler was added in Comparative Example 2, and the acrylic thermosetting adhesive in Example 2 was used directly.

[0112] Performance testing 1. Shore hardness test.

[0113] Shore hardness tests were performed on thermosetting adhesives using a Shore hardness tester.

[0114] 2. Room temperature tensile strength test.

[0115] Epoxy / anaerobic / acrylic thermosetting adhesives and magnetic thermosetting adhesives were prepared into standard-sized I-shaped tensile specimens (gauge length = 25 mm) according to the curing methods of different thermosetting adhesives. Using a universal testing machine, the specimens were clamped in the upper and lower fixtures at room temperature and the tensile speed was 500 mm / min. The bulk strength of the thermosetting adhesive, i.e., the room temperature tensile strength, was then tested.

[0116] 3. Specific saturation magnetization test.

[0117] Using a vibrating sample magnetometer, a cured thermosetting adhesive was prepared into a cured sample block with dimensions of 1 cm × 1 cm × 1 mm. The sample block was placed in a constant magnetic field of -10000 Oe to 10000 Oe, and the MH curve was obtained to obtain the specific saturation magnetization of the sample block.

[0118] 4. Oriented drop test.

[0119] The computer simulates the stress state of the speaker unit during assembly and designs a drop fixture. The product is placed in the drop fixture and dropped from a height of 1.8 m with zero initial velocity. The product is removed from the fixture and its condition is checked every six drops.

[0120] 5. High temperature and high humidity resistance test of magnetic circuit components.

[0121] Place the magnetic circuit component under test in an oven at 80℃ / 90%RH and remove it every 24 hours to observe whether the product shows any adhesion failure.

[0122] The magnetic thermosetting adhesives prepared in Examples 1 and 2 and the thermosetting adhesives prepared in Comparative Examples 1 and 2 were subjected to relevant performance tests. The test results are detailed in Tables 1 and 2.

[0123] Table 1

[0124] Note: In Table 1, the adhesives used in the examples and comparative examples were used to bond the center magnets in the same magnetic circuit system. To ensure consistency, the epoxy thermosetting adhesive used in Comparative Example 1 was used for bonding the side magnets.

[0125] Table 2

[0126] Note: In Table 2, the adhesives used in the examples and comparative examples were used to bond the side magnets in the same magnetic circuit system. Also, considering the lateral attraction of the center magnet to the side magnets, the acrylic thermosetting adhesive used in Comparative Example 2 was used to bond the center magnets.

[0127] The purpose of adding magnetic filler is to improve the acoustic performance of the product. However, it is undeniable that, as can be seen from the test results in Tables 1 and 2, the elongation at break of the adhesive itself is higher than that of the corresponding examples in Comparative Examples 1 and 2. This is because the addition of magnetic filler will introduce stress points at the bonding interface, which will reduce the tensile strength and toughness of the thermosetting adhesive and may reduce the mechanical reliability margin of the product. For loudspeaker products, the center magnet has a large bonding area and a significantly higher overall weight than the side magnets. The failure risk at this bonding point is less due to insufficient bonding strength and more due to the product's drop resistance reliability under its large volume and weight structure. Therefore, in Examples 1 and 2 of Table 1, epoxy and acrylic adhesives were compared. Under the premise of ensuring magnetic conductivity, acrylic resins with excellent elongation at break were selected to prepare thermosetting adhesives. Through their good toughness and deformation ability, they can effectively buffer drop impact stress and minimize the adverse effects of bonding interface defects on the overall mechanical reliability of the device. However, this does not mean that the epoxy thermosetting adhesive in Example 1 has low bonding strength. This is because epoxy resins are more brittle and harder, and defects at tiny sites can lead to product failure, resulting in a lower tolerance for bonding interface defects.

[0128] Edge magnets are mostly chamfered rectangles with narrow short axes and small bonding areas. When using acrylic adhesives to bond edge magnets, the adhesive does not cure at the edges due to oxygen inhibition, further reducing the actual bonding area. Epoxy adhesives do not have this problem; after the edge adhesive cures, it forms a "barrier" around the magnet, preventing moisture from entering and protecting the bonding interface to some extent. Therefore, as shown in Table 2, the edge magnet products bonded with epoxy thermosetting adhesives perform almost identically to Comparative Example 1 under high temperature and high humidity storage at 80℃ / 90%RH. Using epoxy-based magnetic thermosetting adhesives at the edge magnet positions can improve the acoustic performance of the product without compromising its environmental reliability as much as possible. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A magnetically conductive thermosetting adhesive, characterized in that, The product includes a thermosetting adhesive and a magnetic filler dispersed within the thermosetting adhesive. The magnetic filler has a particle size of 0.1 μm to 10 μm and a specific saturation magnetization of 50 emu / g to 250 emu / g. The magnetic filler includes a magnetic material, which includes at least one of iron, nickel, and cobalt, and the magnetic material accounts for ≥90% of the total mass of the magnetic filler.

2. The magnetically conductive thermosetting adhesive as described in claim 1, characterized in that, The magnetic material includes iron, and the mass percentage of iron in the magnetic filler is ≥30%.

3. The magnetically conductive thermosetting adhesive as described in claim 1, characterized in that, The magnetic filler also includes auxiliary materials, which include at least one of silicon, phosphorus, chromium, and aluminum. The auxiliary material accounts for ≤10% of the total mass of the magnetic filler.

4. The magnetically conductive thermosetting adhesive as described in any one of claims 1 to 3, characterized in that, The thermosetting adhesive has a Shore hardness ≥ D60 and a tensile strength ≥ 25 MPa. And / or, the thermosetting adhesive includes at least one of epoxy thermosetting adhesive, acrylic thermosetting adhesive, and anaerobic thermosetting adhesive.

5. The magnetically conductive thermosetting adhesive as described in any one of claims 1 to 3, characterized in that, The magnetic thermosetting adhesive also includes at least one of an antioxidant and an anti-settling agent.

6. The magnetically conductive thermosetting adhesive as described in claim 5, characterized in that, The anti-settling agent comprises nano-sized hydrophobic silica; And / or, the antioxidant includes at least one of antioxidant 1010, antioxidant 1076, and antioxidant 4010.

7. The magnetically conductive thermosetting adhesive as described in claim 5, characterized in that, The magnetically conductive thermosetting adhesive comprises the following components in parts by weight: 50-80 parts thermosetting adhesive, 20-50 parts magnetic filler, 1-5 parts antioxidant, and 1-5 parts anti-settling agent.

8. The magnetically conductive thermosetting adhesive as described in claim 1, characterized in that, The tensile strength of the magnetic thermosetting adhesive is ≥20 MPa; And / or, the specific saturation magnetization of the magnetic thermosetting adhesive is 10 emu / g to 200 emu / g.

9. A method for preparing a magnetically conductive thermosetting adhesive according to any one of claims 1 to 4 and 8, characterized in that, Includes the following steps: Obtain magnetic filler and thermosetting adhesive; the particle size of the magnetic filler is 0.1 μm to 10 μm, and the specific saturation magnetization of the magnetic filler is 50 emu / g to 250 emu / g; The magnetic filler and the thermosetting adhesive are mixed and stirred in the required proportion to obtain the magnetic thermosetting adhesive.

10. A magnetic circuit system for a sound-generating device, characterized in that, The device includes a magnetic yoke and a magnetic circuit assembly disposed on one side of the magnetic yoke. The magnetic circuit assembly includes a magnet and a magnetic plate. The magnetic yoke, the magnet, and the magnetic plate are stacked sequentially along a first direction. The magnetic yoke and the magnet and / or the magnet and the magnetic plate are provided with a magnetic thermosetting adhesive as described in any one of claims 1 to 8, or with a magnetic thermosetting adhesive prepared by the preparation method described in claim 9.

11. The magnetic circuit system for a sound-generating device as described in claim 10, characterized in that, The magnet includes a central magnet and side magnets spaced apart, and the magnetic guide plate includes a central magnetic guide plate and side magnetic guide plates. The central magnet and the central magnetic guide plate constitute a central magnetic part, and the side magnets and the side magnetic guide plates constitute a side magnetic part. The magnetic yoke, the central magnet, and the central magnetic plate are stacked sequentially along a first direction, and the central magnet and the magnetic yoke and / or the central magnet and the central magnetic plate are bonded together by the magnetic thermosetting adhesive. And / or, the magnetic yoke, the side magnet and the side magnetic plate are stacked sequentially along the first direction, and the side magnet and the magnetic yoke and / or the side magnet and the side magnetic plate are bonded together by the magnetic thermosetting adhesive.

12. A sound-generating device, characterized in that, Includes the magnetic circuit system for the sound-generating device as described in claim 10 or 11.

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