Diaphragms for sound-generating devices and sound-generating devices having them

Abstract

This invention discloses a diaphragm for a sound-generating device and a sound-generating device having the same. The diaphragm includes a main body and a conductive part. The main body is made of one of polyetheretherketone, thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, silicone rubber, ethylene-acrylate rubber, acrylate rubber, and hydrogenated nitrile rubber. The conductive part is disposed in the main body, and at least a portion of the conductive part is exposed to electrically connect with the voice coil and external circuit of the sound-generating device. The conductive part includes a matrix and a conductive material dispersed within the matrix. The matrix is ​​formed by reacting and curing a silane-modified polyether adhesive containing a silane-modified polyether prepolymer with moisture. The conductive material accounts for 65wt% to 95wt% of the mass of the conductive part, and the elongation at break of the conductive part is ≤70%. The diaphragm according to the embodiments of this invention has good adhesive strength and toughness, strong adaptability to different types of main body materials, high adhesion, and good toughness.

Description

Technical Field

[0001] This invention relates to the field of electroacoustic technology, and more specifically, to a diaphragm for a sound-generating device and a sound-generating device using the diaphragm. Background Technology

[0002] Currently, the conductive part of the conductive diaphragm commonly used in the loudspeaker field is mainly composed of a polymer matrix and conductive filler. In order to reduce the resistance of the conductive part and improve its conductivity during the manufacturing of the diaphragm, it is usually necessary to increase the amount of conductive filler in the polymer matrix. However, if the amount of conductive filler in the polymer matrix is ​​too large, it will affect the toughness of the conductive part, thereby reducing the toughness of the conductive diaphragm and failing to meet the requirements of the diaphragm.

[0003] Therefore, a new technical solution is needed to meet the toughness requirements of conductive diaphragms. Summary of the Invention

[0004] One object of the present invention is to provide a diaphragm for a sound-generating device that not only has excellent mechanical properties but also good toughness.

[0005] Another object of the present invention is to provide a sound-generating device composed of the diaphragm described above for a sound-generating device.

[0006] To achieve the above objectives, the present invention provides the following technical solutions.

[0007] According to a first aspect of the present invention, a diaphragm for a sound-generating device includes a main body and a conductive portion. The main body is made of one of polyetheretherketone, thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, silicone rubber, ethylene-acrylate rubber, acrylate rubber, and hydrogenated nitrile rubber. The conductive portion is disposed on the main body, and at least a portion of the conductive portion is exposed for electrical connection with the voice coil of the sound-generating device and an external circuit. The conductive portion includes a matrix and a conductive material dispersed within the matrix. The matrix is ​​formed as a film layer cured by reacting a silane-modified polyether adhesive containing a silane-modified polyether prepolymer with moisture. The conductive material accounts for 65wt% to 95wt% of the mass percentage of the conductive portion, and the change rate of the elongation at break of the conductive portion is ≤70% with increasing content of the conductive material in the conductive portion.

[0008] According to some embodiments of the present invention, the silane-modified polyether adhesive contains characteristic groups, which are -Si-O-Si-, -COC-, or silane-based groups.

[0009] According to some embodiments of the present invention, the silane-modified polyether prepolymer accounts for 5 wt% to 35 wt% of the total weight of the conductive portion.

[0010] According to some embodiments of the present invention, the silane-modified polyether prepolymer is at least one of methoxysilane-terminated polyether prepolymer, ethoxysilane-terminated polyether prepolymer, dialkoxysilane-terminated polyether prepolymer, and trialkoxy-terminated polyether prepolymer, wherein the molecular weight of the silane-modified polyether prepolymer is 700 to 45,000.

[0011] According to some embodiments of the present invention, the silane-modified polyether adhesive is cured by reacting with moisture under the action of a catalyst to obtain the matrix, wherein the catalyst is at least one of organotin catalysts, organobismuth catalysts, and amine catalysts.

[0012] According to some embodiments of the present invention, the silane-modified polyether adhesive further comprises a plasticizer, which is at least one selected from phthalates, non-phthalates, dimethyl silicone oil, aliphatic diesters, phosphate esters, and epoxy esters.

[0013] According to some embodiments of the present invention, the silane-modified polyether adhesive further comprises an antioxidant, the antioxidant including at least one of hindered phenols, phosphites, and amines; the hindered phenolic antioxidant is at least one of antioxidant 1010, antioxidant PDP, antioxidant 2246, and antioxidant 264; the phosphite antioxidant is at least one of antioxidant 168, antioxidant 390, and antioxidant 135A; and the amine antioxidant is at least one of antioxidant 445 and antioxidant KY-405.

[0014] According to some embodiments of the present invention, the silane-modified polyether adhesive further comprises a silane coupling agent, wherein the silane coupling agent comprises at least one selected from 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-isocyanate propyltriethoxysilane, and 3-(trimethoxysilylpropyl)isocyanurate.

[0015] According to some embodiments of the present invention, the conductive material is at least one of silver powder, gold powder, copper powder, aluminum powder, nickel powder, carbon-based particles, and conductive composite powder, wherein the carbon-based particles include at least one of carbon black, graphene, and carbon nanotubes, and the conductive composite powder includes at least one combination of silver and copper, silver and nickel, silver and vanadium, silver and indium, and silver and palladium.

[0016] According to some embodiments of the present invention, the volume resistivity of the conductive part is ≤0.17Ω·cm.

[0017] According to some embodiments of the present invention, the elongation at break of the matrix composed of the silane-modified polyether adhesive decreases by less than 50% after aging at 150°C for 48 hours.

[0018] According to some embodiments of the present invention, the thickness of the conductive part is 5 μm to 200 μm.

[0019] A sound-generating device according to a second aspect of the present invention includes a diaphragm for a sound-generating device as described in the above embodiments.

[0020] According to embodiments of the present invention, the diaphragm and the sound-generating device having the diaphragm use a film layer formed by reacting and curing a silane-modified polyether adhesive containing a silane-modified polyether prepolymer with moisture as the conductive part of the diaphragm. The silane-modified polyether adhesive can, on the one hand, encapsulate the conductive material, and on the other hand, provide a molecular skeleton for the cured polymer groups, so that the conductive part has excellent elasticity, adhesive strength, mechanical properties and fatigue resistance. Furthermore, the silane-modified polyether adhesive has high compatibility with conductive materials, and can still maintain good adhesive strength and toughness even when the conductive material has a high filler content. It has strong adaptability to different types of main body materials, high adhesion and good toughness.

[0021] Other features and advantages of the invention will become clear from the following detailed description of exemplary embodiments of the invention with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the invention and, together with their description, serve to explain the principles of the invention.

[0023] Figure 1 This is a schematic diagram of the structure of a diaphragm according to an embodiment of the present invention;

[0024] Figure 2 This is a partial cross-sectional view of a diaphragm according to an embodiment of the present invention;

[0025] Figure 3 This is a partial cross-sectional view of a diaphragm according to another embodiment of the present invention;

[0026] Figure 4 This is a schematic diagram of the diaphragm being tested diagonally in a 3mm*3mm square according to an embodiment of the present invention;

[0027] Figure 5 This is a partial cross-sectional view of a sound-generating device according to an embodiment of the present invention;

[0028] Figure 6 This is a partial cross-sectional view of a sound-generating device according to another embodiment of the present invention.

[0029] Figure label:

[0030] Diaphragm 10; Main body 11; Conductive part 12;

[0031] Voice coil 20; first diaphragm 21; second diaphragm 22. Detailed Implementation

[0032] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention.

[0033] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0034] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0035] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0036] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0037] The diaphragm 10 of the sound-generating device according to an embodiment of the present invention will now be described in detail with reference to the accompanying drawings. The sound-generating device 100 can be a loudspeaker unit, which may include a magnetic circuit system, a diaphragm 10, and a voice coil 20 disposed on the diaphragm 10. One end of the voice coil 20, away from the diaphragm 10, is inserted into the magnetic gap of the magnetic circuit system. When the loudspeaker unit operates, a current flows through the voice coil 20, and the voice coil 20 reciprocates under the action of a magnetic field to drive the diaphragm 10 to vibrate and generate sound.

[0038] like Figures 1 to 6 As shown, the diaphragm 10 for a sound-generating device according to an embodiment of the present invention includes a main body 11 and a conductive part 12. The main body 11 is made of one of polyetheretherketone, thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, silicone rubber, ethylene-acrylate rubber, acrylate rubber, and hydrogenated nitrile rubber. The conductive part 12 is disposed on the main body 11, and at least a portion of the conductive part 12 is exposed to be electrically connected to the voice coil 20 of the sound-generating device and the external circuit.

[0039] The conductive part 12 includes a matrix and a conductive material dispersed in the matrix. The matrix is ​​formed as a film layer formed by reacting and curing a silane-modified polyether adhesive containing a silane-modified polyether prepolymer with moisture. The conductive material accounts for 65wt% to 95wt% of the mass of the conductive part 12. As the content of the conductive material in the conductive part 12 increases, the change rate of the elongation at break of the conductive part 12 is ≤70%.

[0040] In other words, the diaphragm 10 according to the embodiments of the present invention can be used in a sound-generating device. The diaphragm 10 can be composed of two parts: a main body 11 and a conductive part 12. The main body 11 is made of any one of polyetheretherketone, thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, silicone rubber, ethylene-acrylate rubber, acrylate rubber, and hydrogenated nitrile rubber. The main body 11 constitutes the main structure of the diaphragm 10. At least a portion of the conductive part 12 is exposed on the surface of the main body 11. The conductive part 12 exposed on the surface of the main body 11 can be electrically connected to the voice coil 20 of the sound-generating device and the external circuit. The circuit connection operation is simple.

[0041] The conductive part 12 is mainly composed of a substrate and a conductive material. The substrate constitutes the main structure of the conductive part 12. For example, it can be a film layer disposed on the main body 11, that is, the conductive part 12 is also formed as a conductive part 12 film layer structure. The substrate is formed by the reaction and curing of silane-modified polyether adhesive with moisture. The silane-modified polyether adhesive contains silane-modified polyether prepolymer. The silane-modified polyether adhesive containing silane-modified polyether prepolymer serves as the substrate. With the addition of conductive material, it can be cured by moisture at room temperature to prepare the silane-modified polyether conductive part 12. The reaction has good stability and is easy to process and mold.

[0042] Furthermore, when silane-modified polyether adhesive containing silane-modified polyether prepolymer is used to prepare conductive part 12 by adding conductive material, the silane-modified polyether adhesive can encapsulate the conductive material and provide a molecular skeleton for the cured polymer groups. This results in conductive part 12 with excellent toughness, adhesive strength, mechanical properties, and fatigue resistance. The silane-modified polyether adhesive also exhibits high compatibility with conductive materials, maintaining good adhesive strength and toughness even when filled with a high content of conductive material. When the conductive material accounts for 65wt%~95wt% of the conductive part 12 by mass, the change rate of elongation at break of the silane-modified polyether adhesive is ≤70% as the content of conductive material in the conductive part 12 gradually increases. In addition, the matrix containing silane-modified polyether adhesive has strong adaptability to different types of main body material 11, exhibiting high adhesion and good toughness.

[0043] It should be noted that the conductive material can be at least one of silver powder, gold powder, copper powder, aluminum powder, nickel powder, carbon-based particles, and conductive composite powder. Among them, carbon-based particles include at least one of carbon black, graphene, and carbon nanotubes, and conductive composite powder includes at least one combination of silver and copper, silver and nickel, silver and vanadium, silver and indium, and silver and palladium.

[0044] Taking silver powder as the conductive material as an example, the amount of silver powder filling has a significant impact on the conductivity and tensile properties of the conductive part 12. With increasing silver powder content, the change rate of elongation at break of the silane-modified polyether adhesive is ≤70%. When the silver powder content is <65%, the volume resistivity of the prepared conductive part 12 is too high, failing to meet the requirements for current conduction. Gradually increasing the silver powder content in the conductive part 12 results in a more compact arrangement of the silver powder, improving the conductivity of the conductive part 12. However, excessively high silver powder content, such as when the mass percentage of silver powder in the conductive part 12 is >95%, leads to a decrease in the mechanical properties of the conductive part 12, especially a significant reduction in elongation at break, failing to meet the toughness requirements. Table 1 shows the relationship between silver powder content and elongation at break of the conductive part 12. As can be seen from Table 1, with increasing mass percentage of silver powder in the conductive part 12, the elongation at break of the conductive part 12 gradually decreases.

[0045] Table 1. Relationship between different silver powder contents and elongation at break of conductive parts

[0046]

[0047] According to the diaphragm 10 of the present invention, when the content of conductive material in the conductive part 12 is high, for example, higher than 80%, the conductive part 12 can still maintain high adhesion and toughness. One method for evaluating the adhesion of the conductive part 12 is as follows: a 20*5mm conductive part 12 is coated on a PC sheet, and the main body 11 is quickly placed on top of the conductive part 12 for bonding. The raised lines on the PC sheet control the thickness of the conductive part 12 to 0.2mm. The dimensions of the main body 11 are 25*100*0.2mm, and the effective bonding area between the main body 11 and the conductive part 12 is 20*5mm. Excess adhesive is wiped off, and after curing for 24 hours, the 180° peel strength between the main body 11 and the conductive part 12 is tested. Taking a conductive part 12 with 85% silver powder added to the matrix as an example, Table 2 compares the peel strength of conductive parts 12 made of silane-modified polyether adhesive, epoxy resin, and UV resin with that of the main body 11 made of different materials.

[0048] Table 2 Comparison of 180° peel strength between the conductive portion containing 85% silver powder and the main body of different materials.

[0049]

[0050] One method for evaluating the elongation at break of the conductive part 12 is as follows: the elongation at break is measured according to the ASTM D412-2016 standard. The sample shape is dumbbell-shaped, the tensile rate is 500 mm / min, and each group of samples is tested 5 times and the average value is taken. Table 3 shows the changes in elongation at break of the conductive part 12 made of silane-modified polyether resin, the conductive part 12 made of epoxy resin, and the conductive part 12 made of UV resin under different mass percentages of silver powder content.

[0051] Table 3 Comparison of elongation at break of conductive parts made of different materials with different mass percentages of silver powder

[0052]

[0053] The adhesive strength and elongation at break of the conductive part 12 can also be evaluated using the following testing methods:

[0054] Under different strain conditions, the adhesion between the conductive part 12 and the main body 11 varies. The determination is based on whether delamination, separation, or cracking occurs between the conductive part 12 and the main body 11. Taking the addition of 85% silver powder to the substrate as an example, the conductive part 12 is 10μm thick and coated on the surface of the main body 11. It is then cut into a rectangle with dimensions of 10mm*60mm. Under the tensile mode of a tensile tester or DMA device, different deformations are stretched to compare the changes in appearance.

[0055] Table 4 compares the appearance of the conductive parts 12 made of silane-modified polyether resin, epoxy resin, and UV resin with that of the main body 11 made of acrylic rubber under different tensile strain conditions. Table 5 compares the appearance of the conductive parts 12 made of silane-modified polyether resin, epoxy resin, and UV resin with that of the main body 11 made of different materials under a 30% strain condition, when the mass percentage of silver powder in the conductive parts 12 made of silane-modified polyether resin, epoxy resin, and UV resin is 85%.

[0056] Table 4. Comparison of the appearance of conductive parts made of different materials and the main body made of acrylic rubber under different tensile strain conditions.

[0057]

[0058] Table 5. Comparison of the appearance of conductive parts made of different materials with the main body of different materials under 30% strain conditions when the silver powder mass percentage is 85%.

[0059]

[0060] Therefore, it can be seen from the above multiple evaluation methods and evaluation results that, according to the embodiment of the present invention, the diaphragm 10 uses a film layer formed by reacting and curing a silane-modified polyether adhesive containing a silane-modified polyether prepolymer with moisture as the conductive part 12 of the diaphragm 10. The silane-modified polyether adhesive can, on the one hand, encapsulate the conductive material, and on the other hand, provide a molecular skeleton for the cured polymer groups, so that the conductive part 12 has excellent toughness, adhesive strength, mechanical properties and fatigue resistance. Moreover, the silane-modified polyether adhesive has high compatibility with conductive materials, and can still maintain good adhesive strength and toughness even when the conductive material has a high filling amount. Furthermore, the conductive part 12 has strong adaptability to different types of main body 11 materials, high adhesion and good toughness.

[0061] According to one embodiment of the present invention, the silane-modified polyether adhesive contains characteristic groups, namely -Si-O-Si-, -COC-, and silyl groups.

[0062] In other words, silane-modified polyether adhesives containing silane-modified polyether prepolymers contain multiple characteristic groups. These characteristic groups can enhance the encapsulation effect of the silane-modified polyether adhesive on conductive materials, improve the toughness of the silane-modified polyether adhesive, and thus further improve the toughness of the diaphragm. Characteristic groups include -Si-O-Si-, -COC-, silyl groups, etc., and the characteristic group can be any one of these groups or a combination of multiple groups.

[0063] In some specific embodiments of the present invention, the silane-modified polyether prepolymer accounts for 5 wt% to 35 wt% of the total weight of the conductive part 12.

[0064] Specifically, silane-modified polyether prepolymers, under the action of a catalyst, react with moisture in the air to form a cross-linked network structure. The main performance indicators of silane-modified polyether adhesives include hardness, tensile strength, elongation at break, and resistance to high and low temperatures. Within a certain range, the more cross-linking points, the higher the hardness and tensile strength of the silane-modified polyether adhesive, but the lower the elongation at break and resilience. When the content of silane-modified polyether prepolymer in the conductive part 12 is less than 5%, fewer cross-linking points are generated during the reaction, resulting in a low degree of reaction and excessively low strength and toughness of the prepared conductive part 12. When the content of silane-modified polyether prepolymer in the conductive part 12 is greater than 35%, it leads to excessively high resistance, and the resistance value of the prepared conductive part 12 fails to meet the requirements.

[0065] Table 6 shows the relationship between the tensile strength and elongation at break of different conductive parts 12 prepared from silane-modified polyether prepolymers with different mass percentages. As can be seen from Table 3, as the mass percentage of silane-modified polyether prepolymer in the conductive part 12 increases, the degree of crosslinking of the material increases, and the tensile strength and elongation at break of the conductive part 12 also change accordingly.

[0066] Table 6. Effect of the mass percentage of silane-modified polyether prepolymer in the conductive part on the tensile strength and elongation at break of the conductive part.

[0067]

[0068] Therefore, according to the embodiment of the present invention, by controlling the mass percentage of silane-modified polyether prepolymer in the conductive part 12 to be between 5wt% and 35wt%, for example, it can be 5wt%, 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, etc., the tensile strength and elongation at break of the conductive part 12 can be effectively controlled, thereby further ensuring the performance of the diaphragm 10.

[0069] Optionally, according to some embodiments of the present invention, the silane-modified polyether prepolymer is at least one of methoxysilane-terminated polyether prepolymer, ethoxysilane-terminated polyether prepolymer, dialkoxysilane-terminated polyether prepolymer, and trialkoxy-terminated polyether prepolymer, wherein the molecular weight of the silane-modified polyether prepolymer is 700 to 45,000.

[0070] Specifically, the molecular weight of silane-modified polyether prepolymer plays a decisive role in a series of polymer properties. When the molecular weight is too low, less than 700, it will result in low cohesive strength of the silane-modified polyether adhesive, which is not conducive to bonding. When the molecular weight is too high, greater than 45,000, it will result in increased viscosity of the silane-modified polyether adhesive, which is not conducive to construction operations, and also results in poor wetting and uneven coating.

[0071] Therefore, according to the diaphragm 10 of the present invention, by controlling the molecular weight of the silane-modified polyether prepolymer to be between 700 and 45,000, for example, 700, 1,000, 3,000, 5,000, 10,000, 20,000, 30,000, 45,000, etc., the viscosity and toughness of the silane-modified polyether adhesive can be effectively controlled, which facilitates construction operations.

[0072] In some specific embodiments of the present invention, the silane-modified polyether adhesive is reacted with moisture under the action of a catalyst to obtain a matrix, wherein the catalyst is at least one of organotin catalysts, organobismuth catalysts and amine catalysts.

[0073] The main function of the catalyst is to increase the crosslinking speed of the silane-modified polyether adhesive and shorten the curing time. Within a certain range, the crosslinking speed increases with the increase of the catalyst content. When the mass content of the catalyst is less than 0.01 wt% of the total weight of the conductive part 12, the crosslinking speed is slow and the production efficiency is low. When the mass content of the catalyst is greater than 2% of the total weight of the conductive part 12, the crosslinking speed no longer increases and it remains in the silane-modified polyether adhesive, which will cause a decrease in the mechanical properties of the prepared conductive part 12.

[0074] Therefore, according to the embodiment of the present invention, the diaphragm 10, by adjusting the mass percentage of the catalyst during the crosslinking of the silane-modified polyether adhesive, controls the mass percentage of the catalyst to be between 0.01wt% and 2wt% of the total weight of the conductive part 12, for example, 0.01wt%, 0.05wt%, 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%, etc., which can effectively ensure the crosslinking time of the silane-modified polyether adhesive, improve production efficiency, and also ensure the mechanical properties of the conductive part 12.

[0075] Optionally, according to some embodiments of the present invention, the silane-modified polyether adhesive further comprises a plasticizer, which is at least one selected from phthalates, non-phthalates, dimethyl silicone oil, aliphatic diesters, phosphate esters, and epoxy esters.

[0076] The main function of plasticizers is to increase the fluidity of silane-modified polyether rubber, reduce hardness, and adjust modulus. Plasticizers can weaken the van der Waals forces between polymer molecules, thereby increasing the mobility of polymer molecular chains, which means increasing the plasticity of the polymer. This is manifested in a decrease in the hardness, modulus, softening temperature, and embrittlement temperature of the polymer, while the elongation, flexibility, and toughness are improved.

[0077] When the plasticizer content is too low, it cannot reduce the flowability; when the plasticizer content is too high, it will cause the plasticizer to migrate and precipitate, reducing the adhesive strength of the silane-modified polyether adhesive. Optionally, in this application, the mass percentage of the plasticizer can be controlled to be 1% to 1.5% of the total mass of the diaphragm 10, for example, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, etc., thereby ensuring both the adhesive strength of the silane-modified polyether adhesive and the flowability of the product.

[0078] According to one embodiment of the present invention, the silane-modified polyether adhesive further comprises an antioxidant, which includes at least one of hindered phenols, phosphites, and amines; the hindered phenolic antioxidant is at least one of antioxidant 1010, antioxidant PDP, antioxidant 2246, and antioxidant 264; the phosphite antioxidant is at least one of antioxidant 168, antioxidant 390, and antioxidant 135A; and the amine antioxidant is at least one of antioxidant 445 and antioxidant KY-405.

[0079] The main function of antioxidants is to improve the aging resistance of silane-modified polyether adhesives. Antioxidants can capture and neutralize free radicals generated during polymer oxidation, preventing or interrupting their chain reaction, and delaying / preventing oxidative degradation, thereby improving aging resistance. When the antioxidant content is too low, the required aging resistance cannot be achieved; when the antioxidant content is too high, the antioxidant will react directly with molecular oxygen in the formulation to form free radicals, leading to accelerated aging. Optionally, in this application, the mass percentage of antioxidants is 0.08% to 0.2% of the total weight of the diaphragm 10, for example, it can be 0.08%, 0.1%, 0.12%, 0.13%, 0.15%, 0.18%, 0.2%, etc., thereby effectively ensuring the aging resistance of the diaphragm 10.

[0080] In some specific embodiments of the present invention, the silane-modified polyether adhesive further comprises a silane coupling agent, which includes at least one selected from 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-isocyanate propyltriethoxysilane, and 3-(trimethoxysilylpropyl)isocyanurate.

[0081] Silane coupling agents possess two functional groups with different chemical properties. The alkoxy group at one end reacts with moisture in the air to generate active silanol groups, which can then condense with hydroxyl groups on the substrate surface to form stable chemical bonds. The reactive functional group at the other end reacts with the polymer, forming a bridge-like function between the sealant and the substrate, acting as an adhesion promoter. Simultaneously, the silane coupling agent also acts as a crosslinking agent in the polymer curing reaction, increasing the crosslinking density of the final conductive adhesive layer. However, when the content of the silane coupling agent is too low, the effect on increasing the adhesion of the conductive adhesive layer is not significant. When the content of the silane coupling agent is too high, it will cause the coupling agent itself to hydrolyze and undergo a crosslinking reaction, leading to a decrease in the mechanical properties of the conductive adhesive layer. Optionally, in this application, the mass percentage of the silane coupling agent can be 1.3% to 2% of the total weight of the diaphragm 10, for example, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, etc., thereby effectively ensuring the mechanical properties of the diaphragm 10.

[0082] like Figure 2 As shown, according to some embodiments of the present invention, the conductive part 12 is provided on one side surface of the main body part 11.

[0083] In some specific embodiments of the present invention, the conductive part 12 is coated or bonded to one side surface of the main body part 11; or, the main body part 11 and the conductive part 12 are integrally injection molded.

[0084] In other words, the conductive part 12 according to the embodiment of the present invention can be a film layer structure disposed on one side surface of the main body 11. The conductive part 12 can be disposed on the main body 11 by coating or bonding, or it can be integrally formed with the main body 11 by integral molding. Therefore, the diaphragm 10 according to the embodiment of the present invention has a simple structure, is easy to manufacture, and can facilitate the electrical connection of the conductive part 12 with the voice coil 20 of the sound generating device or external circuit.

[0085] Alternatively, in some other embodiments of the present invention, a portion of the conductive portion 12 is embedded in the main body portion 11.

[0086] In other words, such as Figure 3 As shown, according to an embodiment of the present invention, the conductive portion 12 can also be embedded in the main body portion 11. That is, the main body portion 11 may be provided with a groove, a portion of the conductive portion 12 is disposed in the groove provided in the main body portion 11, and the surface of another portion is exposed on the main body portion 11. Furthermore, the outer surface of the conductive portion 12 can be flush with the outer surface of the main body portion 11. Thus, the diaphragm 10 with this structure can effectively ensure the assembly stability of the conductive portion 12 on the main body portion 11. Moreover, the conductive portion 12 being embedded in the main body portion 11 can reduce the thickness of the diaphragm 10 to a certain extent, increasing the design space of the product. In addition, the conductive portion 12 being embedded in the main body portion 11 can improve the vibration consistency between the conductive portion 12 and the main body portion 11, thereby improving the sound production effect of the diaphragm 10.

[0087] According to one embodiment of the present invention, the volume resistivity of the conductive part 12 is ≤0.17Ω·cm.

[0088] Specifically, the lower the volume resistivity of the conductive part 12, the lower the energy consumption of the conductive part 12, and the larger the amplitude of the diaphragm 10 when used in a loudspeaker, resulting in better acoustic performance. For example... Figure 4 As shown, Figure 4 The diagram shows the diagonal test results in a 3mm*3mm square. This test reveals that the higher the resistance of the conductive portion 12, the greater the energy loss of the conductive portion 12 film layer. Consequently, under the same voltage, the amplitude of the diaphragm 10 is smaller, and the acoustic performance is lower. Therefore, according to the embodiment of the present invention, by controlling the volume resistivity of the conductive portion 12 to ≤0.17Ω·cm, the amplitude of the diaphragm 10 can be effectively increased, thereby improving the acoustic performance of the diaphragm 10.

[0089] In some specific embodiments of the present invention, the elongation at break of the matrix composed of silane-modified polyether adhesive decreases by less than 50% after aging at 150°C for 48 hours.

[0090] It is understandable that the silane-modified polyether prepolymer in the silane-modified polyether adhesive can be a modified high-temperature resistant prepolymer, resulting in a high-temperature resistant MS adhesive. Furthermore, antioxidants are added to the silane-modified polyether prepolymer to capture and neutralize active free radicals, preventing oxidative degradation and improving the aging resistance of the matrix. The elongation at break was measured according to ASTM D412-2016 standard. The sample shape was dumbbell-shaped, the tensile rate was 500 mm / min, and each group of samples was tested five times, with the average value taken. The elongation at break of the conductive part 12 prepared by conventional silane-modified polyether adhesive and the conductive part 12 prepared by the high-temperature resistant prepolymer were tested. The test results are shown in Table 7.

[0091] Table 7. Comparison of elongation at break under the same conditions between conductive parts prepared from conventional silane-modified polyether adhesives and conductive parts prepared from high-temperature resistant prepolymers.

[0092]

[0093] Therefore, by selecting the silane-modified polyether prepolymer in the silane-modified polyether adhesive as a modified high-temperature resistant prepolymer, the elongation at break decay rate of the conductive part 12 can be effectively reduced, and the aging resistance of the conductive part 12 can be greatly improved.

[0094] According to some embodiments of the present invention, the thickness of the conductive part 12 is 5 μm to 200 μm.

[0095] It should be noted that when the thickness of the conductive part 12 film layer in the diaphragm 10 is low, for example, less than 5 μm, its conductivity is poor and the resistance is too high, which does not meet the product usage requirements; while when the thickness of the conductive part 12 film layer is high, for example, greater than 200 μm, it will lead to an increase in the weight of the conductive part 12, a decrease in the vibration space, a decrease in the amplitude of the speaker diaphragm 10, and a reduction in acoustic performance.

[0096] Therefore, according to the embodiments of the present invention, by controlling the thickness of the conductive part 12 to be between 5μm and 200μm, such as 5μm, 10μm, 15μm, 50μm, 100μm, 150μm, 200μm, etc., the diaphragm 10 can not only meet the resistance requirements of the diaphragm 10, but also ensure the amplitude and acoustic performance of the diaphragm 10.

[0097] The diaphragm 10 provided by this invention can be configured into a sound-generating device of any structure. For example... Figure 5As shown, the sound-generating device according to an embodiment of the present invention includes a housing, a magnetic circuit system disposed within the housing, and a vibration system cooperating with a vibration system. The vibration system includes a diaphragm 10 and a voice coil 20 coupled to one side of the diaphragm 10. The magnetic circuit system drives the voice coil 20 to vibrate, thereby causing the diaphragm 10 to produce sound. The diaphragm 10 is the diaphragm 10 described in the above embodiment. Specifically, when the sound-generating device is working, after the voice coil 20 is energized, under the action of the magnetic field force of the magnetic circuit system, the voice coil 20 can vibrate up and down to drive the diaphragm 10 to vibrate, and the diaphragm 10 can produce sound when it vibrates. The sound-generating device includes a diaphragm 10 prepared according to the above embodiment of the present invention. The diaphragm 10 can be composed of a main body 11 and a conductive part 12.

[0098] In other specific embodiments of the present invention, such as Figure 6 As shown, the sound-generating device according to an embodiment of the present invention includes a housing and a magnetic circuit system and a vibration system disposed within the housing. The vibration system includes a voice coil 20, a first diaphragm 21 and a second diaphragm 22. The top of the voice coil 20 is connected to the first diaphragm 21. The magnetic circuit system drives the voice coil 20 to vibrate so as to drive the first diaphragm 21 to produce sound. The two ends of the second diaphragm 22 are respectively connected to an external circuit and the bottom of the voice coil 20. The second diaphragm 22 is the diaphragm of the above embodiment.

[0099] In other words, the sound-generating device according to the embodiments of the present invention may further include two diaphragms prepared by the above embodiments of the present invention, namely a first diaphragm 21 and a second diaphragm 22. The first diaphragm 21 can be used to vibrate and generate sound, and the second diaphragm 22 can be used to balance the vibration of the voice coil 20. Specifically, when the sound-generating device is working, after the voice coil 20 is energized, under the action of the magnetic field force of the magnetic circuit system, the voice coil 20 can vibrate up and down to drive the first diaphragm 21 to vibrate, and the first diaphragm 21 can generate sound when it vibrates. The second diaphragm 22 can also vibrate up and down with the voice coil 20. Since the two ends of the second diaphragm 22 are respectively connected to the external circuit and the bottom of the voice coil 20, the second diaphragm 22 can balance the vibration of the voice coil 20 and prevent the voice coil 20 from becoming polarized, thereby improving the sound generation effect of the sound-generating device.

[0100] It should be noted that the first diaphragm 21 and the second diaphragm 22 can both adopt the diaphragm 10 of the above embodiments of the present invention, or one of the first diaphragm 21 and the second diaphragm 22 can adopt the diaphragm 10 of the above embodiments of the present invention. The present invention does not make specific limitations in this regard.

[0101] The diaphragm 10 of the present invention will be described below with reference to specific embodiments.

[0102] Example 1

[0103] The thermoplastic polyester elastomer is used as the main body 11, and the formulation of the conductive part 12 film layer is as follows: 31 parts of high temperature resistant silane modified polyether oligomer, 65 parts of conductive silver powder, 1.5 parts of plasticizer, 0.3 parts of catalyst, 0.2 parts of antioxidant, and 2 parts of silane coupling agent.

[0104] The prepared diaphragm 10 does not have the problem of non-curing, and the construction process is simple, does not require heating curing, and the released gas is alcohol, which is green, environmentally friendly and low in energy consumption; at the same time, the conductive part 12 has a low volume resistivity of 0.16 Ω·cm, an elongation at break of 179%, low resistance and good flexibility; after baking in an oven at 150℃ for 48 hours, the elongation at break can still be maintained at 104%.

[0105] Example 2

[0106] The formulation of the conductive layer 12, with acrylic rubber as the main body 11, is as follows: 17 parts of high-temperature resistant silane-modified polyether oligomer, 80 parts of conductive silver powder, 1.2 parts of plasticizer, 0.2 parts of catalyst, 0.1 parts of antioxidant, and 1.5 parts of silane coupling agent.

[0107] The prepared diaphragm 10 does not have the problem of non-curing. At the same time, the conductive part 12 has a low volume resistivity of 0.12 Ω·cm and an elongation at break of 112%. It has low resistance, high elongation at break, and excellent comprehensive performance. After baking in an oven at 150℃ for 48 hours, the elongation at break can still be maintained at 62%.

[0108] Example 3

[0109] The formulation of the conductive part 12 film layer, with ethylene-acrylate rubber as the main body 11, is as follows: 7.5 parts of high-temperature resistant silane-modified polyether oligomer, 90 parts of conductive silver powder, 1 part of plasticizer, 0.12 parts of catalyst, 0.08 parts of antioxidant, and 1.3 parts of silane coupling agent.

[0110] The prepared diaphragm 10 does not have the problem of non-curing. At the same time, the conductive part 12 has a low volume resistivity of 0.07 Ω·cm, an elongation at break of 69%, very low resistance, and good flexibility, which can meet the acoustic performance requirements of the diaphragm. After baking in an oven at 150℃ for 48 hours, the elongation at break can still be maintained at 36%.

[0111] Comparative Example

[0112] The formulation of the conductive part 12 film layer, with acrylate rubber as the main body 11, is as follows: 15 parts epoxy resin, 80 parts conductive silver powder, 1 part phthalic plasticizer, and 4 parts amine curing agent.

[0113] The prepared diaphragm 10 was cured at 100℃ for 2 hours, and there was no phenomenon of non-curing. At the same time, the volume resistivity of the conductive adhesive layer was 0.11 Ω·cm and the elongation at break was 13%. It has low resistance but low elongation and poor flexibility, which does not meet the vibration requirements of the diaphragm.

[0114] The method for testing the elongation at break of the diaphragm 10 in the above embodiments and comparative examples is as follows: Following the ASTM D412-2016 standard, the sample shape is dumbbell-shaped, with a thickness of 0.5 mm, and a tensile rate of 500 mm / min. Each sample is tested 5 times, and the average value is taken. The method for testing the diaphragm at 30% strain is as follows: the thickness of the main body 11 is 200 μm, and the thickness of the conductive part 12 is 10 μm. The conductive part 12 is coated onto the surface of the main body 11, cured, and then cut into rectangles with dimensions of 10 mm * 60 mm. Under the tensile mode of a tensile tester or DMA device, a 30% strain is applied, and then the external force is removed. The appearance changes of the main body 11 and the conductive part 12 are observed. The final test results are shown in Table 8.

[0115] Table 8. Comparison of material ratios and test data between the examples and comparative examples.

[0116]

[0117] As shown in Table 8, in Examples 1 to 3, the same high-temperature resistant MS resin was used as the matrix. With the increase of silver powder content in the conductive part 12, the volume resistivity and elongation at break of the conductive part 12 gradually decreased. After baking at 150℃ for 48 hours, the elongation at break decreased by less than 50%, and the temperature resistance met the product reliability requirements. In contrast, compared with the comparative examples, the epoxy resin had low volume conductivity but also excessively low elongation at break, failing to meet the vibration requirements of the diaphragm 10. Even with better temperature resistance, it could not be used.

[0118] In summary, according to the embodiments of the present invention, the conductive part 12 of the diaphragm 10 has excellent toughness, adhesive strength, mechanical properties and fatigue resistance. Furthermore, the silane-modified polyether adhesive has high compatibility with conductive materials, and can maintain good adhesive strength and toughness even when the conductive material has a high filling amount. Thus, the filling amount of conductive material can be increased while meeting the usage requirements, thereby improving the conductivity of the diaphragm 10. In addition, the conductive part 12 has strong adaptability to different types of main body 11 materials, high adhesion and good flexibility.

[0119] While specific embodiments of the invention have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of the invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the invention. The scope of the invention is defined by the appended claims.

Claims

1. A diaphragm for a sound-generating device, characterized in that, The diaphragm includes a main body and a conductive part. The main body is made of one of polyetheretherketone, thermoplastic polyester elastomer, thermoplastic polyurethane elastomer, silicone rubber, ethylene-acrylate rubber, acrylate rubber, and hydrogenated nitrile rubber. The conductive part is disposed in the main body, and at least a portion of the conductive part is exposed to be electrically connected to the voice coil of the sound-generating device and external circuitry. The conductive part includes a matrix and a conductive material dispersed in the matrix. The matrix is ​​formed as a film layer formed by reacting and curing a silane-modified polyether adhesive containing a silane-modified polyether prepolymer with moisture. The conductive material accounts for a mass percentage of greater than 65 wt% and less than 95 wt% of the conductive part, and the change rate of elongation at break of the conductive part is ≤70%. The silane-modified polyether prepolymer accounts for a mass percentage greater than 5 wt% and less than 35 wt% of the total weight of the conductive portion. The volume resistivity of the conductive part is ≤0.17Ω·cm; the thickness of the conductive part is 5μm~200μm.

2. The diaphragm for a sound-generating device according to claim 1, characterized in that, The silane-modified polyether adhesive contains characteristic groups, namely -Si-O-Si-, -COC-, and silane-based groups.

3. The diaphragm for a sound-generating device according to claim 1, characterized in that, The silane-modified polyether prepolymer is at least one of methoxysilane-terminated polyether prepolymer, ethoxysilane-terminated polyether prepolymer, dialkoxysilane-terminated polyether prepolymer, and trialkoxy-terminated polyether prepolymer, and the molecular weight of the silane-modified polyether prepolymer is 700~45000.

4. The diaphragm for a sound-generating device according to claim 1, characterized in that, The silane-modified polyether adhesive is cured by reacting with moisture under the action of a catalyst to obtain the matrix. The catalyst is at least one of organotin catalysts, organobismuth catalysts, and amine catalysts.

5. The diaphragm for a sound-generating device according to claim 1, characterized in that, The silane-modified polyether adhesive further comprises a plasticizer, which is at least one selected from phthalates, non-phthalates, dimethyl silicone oil, aliphatic diesters, phosphate esters, and epoxy esters.

6. The diaphragm for a sound-generating device according to claim 1, characterized in that, The silane-modified polyether adhesive further comprises an antioxidant, which includes at least one of hindered phenols, phosphites, and amines; The hindered phenolic antioxidant is at least one of antioxidant 1010, antioxidant PDP, antioxidant 2246 and antioxidant 264; The phosphite antioxidant is at least one of antioxidant 168, antioxidant 390 and antioxidant 135A; The amine antioxidant is at least one of antioxidant 445 and antioxidant KY-405.

7. The diaphragm for a sound-generating device according to claim 1, characterized in that, The silane-modified polyether adhesive further comprises a silane coupling agent, which includes at least one of 3-aminopropyltrimethoxysilane, vinyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-isocyanate propyltriethoxysilane, and 3-(trimethoxysilylpropyl)isocyanurate.

8. The diaphragm for a sound-generating device according to claim 1, characterized in that, The conductive material is at least one of silver powder, gold powder, copper powder, aluminum powder, nickel powder, carbon-based particles, and conductive composite powder. The carbon-based particles include at least one of carbon black, graphene, and carbon nanotubes. The conductive composite powder includes at least one combination of silver and copper, silver and nickel, silver and vanadium, silver and indium, and silver and palladium.

9. The diaphragm for a sound-generating device according to claim 1, characterized in that, The elongation at break of the matrix composed of the silane-modified polyether adhesive decreased by less than 50% after aging at 150°C for 48 hours.

10. A sound-generating device, characterized in that, Includes a diaphragm for a sound-generating device according to any one of claims 1-9.

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