Diaphragm and sound emitting device

Abstract

The application discloses a vibrating diaphragm and a sound production device, and the vibrating diaphragm comprises a mixed carboxyl nitrile rubber film layer, which is formed by mixing carboxyl nitrile raw rubber, a vulcanizing agent, a reinforcing agent, an antioxidant and other additives, wherein the reinforcing agent is carbon black, the content of the carboxyl nitrile raw rubber is 100 parts by mass, the content of the carbon black is 15 parts by mass to 75 parts by mass, and the particle size of the carbon black is less than 60 nm. The vibrating diaphragm of the application comprises the mixed carboxyl nitrile rubber film layer, wherein the content of the carbon black is limited to 15 parts by mass to 75 parts by mass, and the particle size of the carbon black is less than 60 nm, so that the vibrating diaphragm has higher tensile strength and elastic recovery rate, and the waterproof capability of the vibrating diaphragm is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electro-acoustic equipment, and particularly relates to a diaphragm of a sound production device and a sound production device comprising the same. BACKGROUND

[0002] The sound production devices of existing wearable products such as earphones, smart watches, smart bracelets, VR and AR products are mostly made of thermoplastic elastomer materials or rubber materials. For thermoplastic elastomers, a thermoplastic polyurethane elastomer (TPU) and a thermoplastic polyester elastomer (TPEE) composite diaphragm is mostly used. For rubber materials, hydrogenated nitrile rubber (HNBR) is mostly used.

[0003] With the increasing demand for waterproof performance of sound production devices, the thermoplastic elastomer (such as TPEE composite diaphragm) used in the sound production devices in the prior art will have a glue cracking phenomenon. The AEM rubber has low tensile strength, is prone to diaphragm rupture, and has low resilience and poor acoustic performance after waterproof reliability.

[0004] Therefore, there is an urgent need to develop a new diaphragm for sound production devices, which has high tensile strength, elastic recovery force and waterproof ability. SUMMARY

[0005] An object of the present application is to provide a diaphragm which can solve the technical problem of poor waterproof performance of the diaphragm of the sound production device in the prior art.

[0006] Another object of the present application is to provide a sound production device having the above diaphragm.

[0007] According to a first aspect of the present application, a diaphragm is provided, comprising a mixed carboxyl nitrile rubber film layer, which is mixed from carboxyl nitrile raw rubber, vulcanizing agent, reinforcing agent, anti-aging agent and other additives, wherein the reinforcing agent is carbon black, the content of the carboxyl nitrile raw rubber is 100 parts by mass, the content of the carbon black is 15-75 parts by mass, and the particle size of the carbon black is less than 60 nm.

[0008] Optionally, the tensile strength of the mixed carboxyl nitrile rubber film layer is greater than or equal to 15 MPa, and the elastic recovery rate is greater than or equal to 80%.

[0009] Optionally, the waterproof level of the diaphragm is not less than 15 ATM.

[0010] Optionally, the content of carboxyl in the mixed carboxyl nitrile rubber film layer is 0.2wt%-6wt%.

[0011] Optionally, the content of acrylonitrile groups in the carboxyl groups in the mixed carboxyl nitrile rubber film layer is 10wt%-35wt%.

[0012] Optionally, the vulcanizing agent is at least one of amine vulcanizing agent, epoxy vulcanizing agent, sulfur, and peroxide.

[0013] Optionally, the content of the vulcanizing agent is 1 part by mass-20 parts by mass.

[0014] Optionally, the other auxiliary agent contains a vulcanization accelerator, and the vulcanization accelerator is at least one of tertiary amine, substituted urea, phenol, imidazole, acetylacetone metal salt, boron trifluoride complex thiazole, sulfenamide, thiuram, thiourea, dithio carbamate, aldehyde amine, arsine, and xanthate.

[0015] Optionally, the content of the vulcanization accelerator is 0.1 part by mass-8 parts by mass.

[0016] Optionally, the antioxidant is at least one of antioxidant 1010, antioxidant 2, antioxidant 6, antioxidant 4, antioxidant 1076, antioxidant 168, antioxidant RD, antioxidant AW, antioxidant DD, antioxidant BLE, antioxidant 4010, 4010NA, 4020, 4030, 4040, antioxidant DNP, antioxidant H, antioxidant A, antioxidant D, antioxidant SP, antioxidant 264, antioxidant 2246, antioxidant 2246-S, antioxidant NBC, and antioxidant MB.

[0017] Optionally, the content of the antioxidant is 0.5 part by mass-6 parts by mass.

[0018] Optionally, the other auxiliary agent includes at least one of stearic acid, ultraviolet absorber, and color paste.

[0019] Optionally, the diaphragm is formed into a single-layer structure including only one layer of the mixed carboxyl nitrile rubber film layer, or the diaphragm is formed into a composite layer structure including at least one layer of the mixed carboxyl nitrile rubber film layer.

[0020] According to a second aspect of the present application, a sound generating device is provided, which includes the diaphragm as described above.

[0021] One technical effect of the present application is that the diaphragm is prepared by using the mixed carboxyl nitrile rubber film layer, the carbon black is used as the reinforcing agent in the mixed carboxyl nitrile rubber film layer, and the content of the carbon black is 15 parts by mass-75 parts by mass, and the particle size of the carbon black is less than 60nm, which can ensure that the diaphragm has high tensile strength and elastic recovery rate, thereby greatly improving the waterproof effect of the diaphragm.

[0022] Other features of the present application, its nature and advantages will become more apparent from the detailed description of exemplary embodiments of the application which follows, with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0024] Figure 1 Structure diagram of a diaphragm according to one embodiment of the present application;

[0025] Figure 2 Partial sectional view of a sound emitting device according to one embodiment of the present application;

[0026] Figure 3 Partial sectional view of a sound emitting device according to another embodiment of the present application;

[0027] Figure 4 Comparison chart of tensile strength, elastic recovery, waterproof membrane breaking rate and sound quality rate of examples and comparative examples.

[0028] REFERENCE NUMERALS

[0029] Diaphragm 10; main body portion 11; conductive portion 12;

[0030] Voice coil 20; first diaphragm 21; second diaphragm 22. DETAILED DESCRIPTION

[0031] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of the components and steps set forth in the embodiments, numerical expressions, and numerical values are not limiting to the scope of the present application unless otherwise specifically stated.

[0032] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting to the scope of the application or its applications or uses.

[0033] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and apparatus should be considered as being part of the specification.

[0034] In all of the examples shown and discussed herein, any specific values should be interpreted as merely illustrative and not as a limitation on the scope of the exemplary embodiments. Thus, other examples of the exemplary embodiments can have different values.

[0035] It should be noted that like numerals and letters refer to like items throughout the drawings, and once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0036] The diaphragm and sound-generating device according to embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Wherein, as... Figures 1 to 3 As shown, the sound-generating device can be a speaker unit, which can include a magnetic circuit system, a diaphragm 10, and a voice coil 20 disposed on the diaphragm 10. The end of the voice coil 20 away from the diaphragm 10 is inserted into the magnetic gap of the magnetic circuit system. When the speaker unit is working, current flows through the voice coil 20, and the voice coil 20 reciprocates under the action of the magnetic field force to drive the diaphragm 10 to vibrate and generate sound.

[0037] The diaphragm 10 according to an embodiment of the present invention comprises a compounded carboxylated nitrile rubber film layer, which is compounded from carboxylated nitrile raw rubber, vulcanizing agent, reinforcing agent, antioxidant and other additives. The reinforcing agent is carbon black, the content of carboxylated nitrile raw rubber is 100 parts by mass, the content of carbon black is 15 parts by mass to 75 parts by mass, and the particle size of carbon black is less than 60 nm.

[0038] In other words, the diaphragm 10 according to the embodiments of the present invention is made of carboxylated nitrile rubber (XNBR), and the diaphragm 10 can be prepared by compounding a carboxylated nitrile rubber film layer, which can be compounded by mixing carboxylated nitrile raw rubber, vulcanizing agent, reinforcing agent, antioxidant and other additives.

[0039] The molecular formula of carboxylated butadiene-acrylonitrile raw rubber is shown in formula (Ⅰ).

[0040]

[0041] In formula (Ⅰ), a, b, c, and d are natural numbers. The original monomer of X can be an ethylene unsaturated monocarboxylic acid or an ethylene unsaturated dicarboxylic acid. The ethylene unsaturated monocarboxylic acid can be acrylic acid, methacrylic acid, ethylacrylic acid, crotonic acid, cinnamic acid, etc.; the ethylene unsaturated dicarboxylic acid can be fumaric acid, maleic acid, pentenic acid, allylmalonic acid, mesocarboxylic acid, tocanic acid, edaconic acid, niconic acid, etc.

[0042] As can be seen, the diaphragm 10 in this embodiment of the invention uses XNBR rubber, and nitrile rubber itself is a tensile crystalline rubber with the advantage of high tensile strength. Furthermore, the addition of carboxyl groups increases its polarity, resulting in a significant increase in strength. Therefore, the membrane will not rupture under higher water pressure.

[0043] In addition, carbon black is used as the reinforcing agent, which enables the prepared compounded carboxylated nitrile rubber film layer to have both good tensile strength and elastic recovery rate, thereby giving the diaphragm 10 a good waterproof effect.

[0044] Specifically, carbon black is an amorphous structure where particles aggregate through physicochemical bonding. The primary structure of carbon black consists of these aggregates, which, through van der Waals forces or hydrogen bonds, can form a spatial network structure—its secondary structure. The surface of carbon black contains hydrogen, carboxyl, lactone, free radical, and quinone groups capable of substitution, reduction, and oxidation reactions. When carbon black is added to XNBR rubber, due to the strong interaction between the carbon black surface and the XNBR rubber interface, the molecular chains of the compounded carboxylated nitrile rubber film tend to slide easily on the carbon black surface under stress, but are not easily detached from the carbon black. The elastomer and carbon black form a strong, sliding bond, increasing the mechanical strength of the compounded carboxylated nitrile rubber film. This improves the tensile strength and elastic recovery rate of the compounded carboxylated nitrile rubber film, thereby enhancing the waterproof performance of the diaphragm 10.

[0045] Furthermore, in this embodiment of the invention, based on a carboxylated nitrile rubber content of 100 parts by mass, the carbon black content is limited to 15 parts by mass to 75 parts by mass. By using carbon black within this content range, a strong interaction between the carbon black and the carboxylated nitrile rubber interface can be ensured. It should be noted that when the amount of carbon black is less than 15 parts by mass, the reinforcing effect on the carboxylated nitrile rubber is poor, resulting in low tensile strength of the compounded carboxylated nitrile rubber film layer, and the diaphragm 10 is prone to rupture after waterproofing reliability. When the amount of carbon black is greater than 75 parts by mass, the tensile strength of the compounded carboxylated nitrile rubber film layer is high, but due to the reduced proportion of rubber inside the carboxylated nitrile rubber, the rebound is small, resulting in poor elastic recovery of the diaphragm 10. After waterproofing reliability, the film does not rebound, thus the obtained diaphragm 10 cannot meet the waterproofing requirements. Optionally, the carbon black content can be 15 parts by weight, 20 parts by weight, 30 parts by weight, 40 parts by weight, 50 parts by weight, 60 parts by weight, 70 parts by weight, or 75 parts by weight. By limiting the carbon black content, the use of carbon black can be prevented from affecting the elastic recovery rate of the compounded carboxylated nitrile rubber film layer, thereby ensuring the waterproof effect of the diaphragm 10.

[0046] Furthermore, in this embodiment of the invention, the carbon black particle size is less than 60 nm, which is beneficial to ensuring that the diaphragm 10 has a good waterproof effect. It should be noted that the smaller the size of the carbon black, the stronger its bonding ability with XNBR rubber and the better its reinforcing ability; while the larger the particle size, the smaller the specific surface area, the weaker the bonding ability between XNBR rubber and carbon black, the worse the resilience of the prepared compounded carboxylated nitrile rubber film layer, and consequently the worse the waterproof effect of the obtained diaphragm 10.

[0047] The tensile strength and elastic recovery rate of compounded carboxylated nitrile rubber films with different carbon black particle sizes were tested. The test results are shown in Table 1 below.

[0048] Table 1. Tensile strength and elastic recovery rate of carbon black with different particle sizes

[0049] Carbon black particle size / nm 20 40 60 80 100 Tensile strength / MPa 35 32 28 25 18 Tensile resilience / % 96 92 86 77 70

[0050] As can be seen from Table 1, in the embodiments of the present invention, limiting the size of carbon black can directly affect the reinforcing strength and resilience of the compounded carboxylated nitrile rubber film layer, thereby ensuring that the diaphragm has a good waterproof effect.

[0051] Therefore, the diaphragm according to the present invention is prepared by a compounded carboxylated nitrile rubber film layer, wherein carbon black is used as a reinforcing agent in the compounded carboxylated nitrile rubber film layer, and the content of carbon black is 15 parts by mass to 75 parts by mass, and the particle size of carbon black is less than 60 nm, thereby improving the tensile strength and elastic recovery rate of the diaphragm, thereby improving the waterproof effect of the diaphragm.

[0052] According to one embodiment of the present invention, the tensile strength of the compounded carboxylated nitrile rubber membrane is ≥15MPa and the elastic recovery rate is ≥80%, which enables the prepared compounded carboxylated nitrile rubber membrane to have both tensile strength and elastic recovery rate, thus ensuring the waterproof and acoustic performance of the diaphragm 10.

[0053] The tensile strength and elastic recovery rate of compounded carboxylated nitrile rubber films with different carbon black contents were tested below.

[0054] The elastic recovery rate test method is as follows:

[0055] A 100mm*15mm*0.1mm rubber membrane was made and placed in a fixture. The length of the fixture was recorded as l0. The membrane was stretched to 100% strain and its length was recorded as l1. The membrane was kept under these conditions for 24 hours. After the stress was removed, the membrane was left to stand for 24 hours and the length of the stretched part was measured as l2.

[0056] Elastic recovery rate = l1 - l0 / L2 * 100%.

[0057] The tensile strength test method is as follows:

[0058] Take the diaphragm 10 raw material from the table above and test its tensile strength according to the ASTM-D882 test standard, with a gauge length of 30 mm and a tensile rate of 300 mm / min.

[0059] The test results for elastic recovery rate and tensile strength are shown in Table 2 below.

[0060] Table 2. Tensile strength and elastic recovery rate with different carbon black contents

[0061] Carbon black / mass parts 10 30 50 70 90 Tensile strength / MPa 12 22 32 44 58 Elastic recovery rate / % 95 93 88 80 75

[0062] As shown in Table 2 above, when the carbon black content is 10 parts by mass, the tensile strength of the compounded carboxylated nitrile butadiene rubber film is 12 MPa, and the elastic recovery rate is 95%. When the carbon black content is 90 parts by mass, the tensile strength of the compounded carboxylated nitrile butadiene rubber film is 58 MPa, and the elastic recovery rate is 75%. In comparison, when the carbon black content is 30 parts by mass, the tensile strength of the compounded carboxylated nitrile butadiene rubber film is 22 MPa, and the elastic recovery rate is 93%. When the carbon black content is 50 parts by mass, the tensile strength of the compounded carboxylated nitrile butadiene rubber film is 32 MPa, and the elastic recovery rate is 88%. When the carbon black content is 70 parts by mass, the tensile strength of the compounded carboxylated nitrile butadiene rubber film is 44 MPa, and the elastic recovery rate is 80%.

[0063] It is evident that when the carbon black content is less than 15 parts by mass, the tensile strength of the compounded carboxylated nitrile rubber membrane is low; when the carbon black content is greater than 75 parts by mass, the elastic recovery rate of the compounded carboxylated nitrile rubber membrane is low. However, when the carbon black content is between 15 and 75 parts by mass, and the carbon black particle size is controlled to be less than 60 nm, the tensile strength of the compounded carboxylated nitrile rubber membrane is ≥15 MPa, and the elastic recovery rate is ≥80%, ensuring that the diaphragm prepared from the compounded carboxylated nitrile rubber membrane possesses both good waterproof performance and excellent acoustic performance.

[0064] According to one embodiment of the present invention, the waterproof rating of the diaphragm 10 is not less than 15 ATM, that is, the waterproof rating of the diaphragm 10 exceeds 150m, for example, the waterproof rating of the diaphragm 10 is 15 ATM, 16 ATM, 17 ATM, etc., thereby meeting the specific waterproof requirements of acoustic equipment, enabling the acoustic equipment to work normally underwater and meet the usage requirements.

[0065] In some specific embodiments of the present invention, the carboxyl content in the compounded carboxylated nitrile rubber film layer is 0.2wt% to 6wt%, and the prepared diaphragm 10 has high mechanical strength and resilience, which can improve the waterproof capability of the diaphragm 10. It should be noted that the carboxyl content in the raw rubber of carboxylated nitrile rubber affects the crosslinking density. When the carboxyl content is less than 0.2wt%, the crosslinking density is low, the material polarity is low, and the strength of the prepared diaphragm 10 is low; while when the carboxyl content is greater than 6wt%, the carboxyl content is too high, the resilience of the prepared diaphragm 10 decreases, and it cannot meet the waterproof requirements of the diaphragm 10. It can be seen that in the embodiments of the present invention, the carboxyl content in the compounded carboxylated nitrile rubber film layer is 0.2wt% to 6wt%, which can ensure that the diaphragm 10 has mechanical properties, acoustic properties and waterproof capability. Optionally, the carboxyl content in the compounded carboxylated nitrile rubber film layer is 0.2wt%, 0.5wt%, 1wt%, 2wt%, 4wt%, 6wt%, etc.

[0066] According to one embodiment of the present invention, the content of acrylonitrile groups in the carboxyl group of the compounded carboxyl nitrile rubber membrane layer is 10wt% to 35wt%, which can ensure that the diaphragm 10 has cold resistance, acoustic performance and waterproof performance.

[0067] It should be noted that nitrile groups are highly polar groups with high electronegativity. When the acrylonitrile content is less than 10 wt%, the molecular chains of the compounded carboxylated nitrile rubber film have good flexibility, low intermolecular forces, and a low glass transition temperature. However, its tensile strength is low and its resilience is poor, which cannot meet the requirements of diaphragm 10. As the acrylonitrile content increases, the polarity of the compounded carboxylated nitrile rubber film increases, the flexibility of the molecular chains decreases, the intermolecular forces increase, the glass transition temperature is higher, the content of double bonds in the molecular chains decreases, the degree of saturation increases, its oil resistance and airtightness improve, its relative density increases, the vulcanization speed is accelerated, and the tensile strength performance improves, but the processability and cold resistance decrease, and the resilience performance decreases. In particular, when the content of acrylonitrile blocks is greater than 35 wt%, the resilience of the compounded carboxylated nitrile rubber film decreases. After reliability is compromised, diaphragm 10 deforms and does not rebound, failing to meet the waterproof requirements.

[0068] As can be seen, in this embodiment of the invention, the content of acrylonitrile groups in the carboxyl group of the compounded carboxyl-based nitrile rubber film layer is 10wt% to 35wt%, which ensures that the prepared diaphragm 10 has good waterproof performance while possessing oil resistance, processability, cold resistance, and tensile strength. Optionally, the content of acrylonitrile groups in the carboxyl group of the compounded carboxyl-based nitrile rubber film layer is 10wt%, 15wt%, 20wt%, 30wt%, 35wt%, etc.

[0069] In some specific embodiments of the present invention, the vulcanizing agent is at least one selected from amine vulcanizing agents, epoxy vulcanizing agents, sulfur, and peroxides. Optionally, the amine vulcanizing agent includes at least one selected from hexamethylenediamine, hexamethylenediamine salt, hexamethylenediamine carbamate, triethylenetetramine, methylenediphenylamine, and di-o-tolueneguanidine. Optionally, the epoxy vulcanizing agent has at least two functional groups, including at least one selected from phenolic glycidyl ether epoxy resins, glycidyl ester epoxy resins, glycidyl amine epoxy resins, linear aliphatic epoxy resins, and alicyclic epoxy resins.

[0070] According to one embodiment of the present invention, the content of the vulcanizing agent is 1 part by mass to 20 parts by mass, which is beneficial to ensure that the diaphragm 10 has a waterproof effect. It should be noted that when the content of the vulcanizing agent is less than 1 part by mass, the degree of cross-linking is low, resulting in poor resilience and a low elastic recovery rate of the diaphragm 10, which fails to meet the waterproof requirements. When the content of the vulcanizing agent is higher than 20 parts by mass, the cross-linking is too high, resulting in an excessively low elongation at break of the diaphragm 10. Under strong water pressure, the diaphragm 10 is prone to rupture, meaning it cannot meet the waterproof requirements. Optionally, the content of the vulcanizing agent can be 1 part by mass, 2 parts by mass, 5 parts by mass, 8 parts by mass, 10 parts by mass, 15 parts by mass, and 20 parts by mass, etc.

[0071] In some specific embodiments of the present invention, other additives contain a vulcanization accelerator, which is at least one selected from tertiary ammonium compounds, substituted ureas, phenols, imidazoles, metal acetylacetone salts, boron trifluoride complex thiazoles, sulfenamides, thiurams, thioureas, dithiocarbamates, aldehyde amines, arsenides, and xanthates. Optionally, a peroxide is used as the vulcanizing agent, in which case the vulcanization accelerator is selected from triallyl isocyanate, triallyl cyanurate, and N,N-m-m-bismaleimide.

[0072] In some specific embodiments of the present invention, the content of the vulcanization accelerator is 0.1 parts by weight to 8 parts by weight, which ensures the tensile strength of the compounded carboxylated nitrile rubber film layer and is beneficial to the waterproofness of the diaphragm 10. It should be noted that when the content of the vulcanization accelerator is less than 0.1 parts by weight, the acceleration efficiency is low, the reaction time is too long, and the cost of manufacturing the diaphragm 10 is high. When the content of the vulcanization accelerator is higher than 8 parts by weight, the acceleration efficiency is high, but scorching is prone to occur during the preparation of the diaphragm 10, the storage time is too short, and the vulcanization accelerator has poor compatibility with the carboxylated nitrile rubber, easily migrating and precipitating from the carboxylated nitrile rubber. Due to the poor compatibility, the tensile strength of the compounded carboxylated nitrile rubber film layer is reduced, which is detrimental to the waterproof reliability of the diaphragm 10. Optionally, the content of the vulcanization accelerator is 0.1 parts by weight, 1 part by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 7 parts by weight, 8 parts by weight, etc.

[0073] According to one embodiment of the present invention, the antioxidant is at least one selected from antioxidant 1010, antioxidant 2, antioxidant 6, antioxidant 4, antioxidant 1076, antioxidant 168, antioxidant RD, antioxidant AW, antioxidant DD, antioxidant BLE, antioxidant 4010, 4010NA, 4020, 4030, 4040, antioxidant DNP, antioxidant H, antioxidant A, antioxidant D, antioxidant SP, antioxidant 264, antioxidant 2246, antioxidant 2246-S, antioxidant NBC, and antioxidant MB. By adding the above antioxidant, the service life of the diaphragm 10 can be extended.

[0074] In some specific embodiments of the present invention, the content of the antioxidant is 0.5 parts by weight to 6 parts by weight, which can extend the service life of the diaphragm 10. It should be noted that if the content of the antioxidant is less than 0.5 parts by weight, the insufficient amount will not achieve the effect of extending the service life of the diaphragm 10; if the content of the antioxidant is greater than 6 parts by weight, i.e., excessive amount of antioxidant is used, the antioxidant is difficult to miscibly dissolve with the elastomer, making it difficult to disperse uniformly, resulting in a decrease in the mechanical properties of the diaphragm 10 material, and the antioxidant is prone to precipitation to the surface over time. Therefore, in the embodiments of the present invention, by using an antioxidant within the above-mentioned range, a better effect of extending the service life can be achieved. Optionally, the content of the antioxidant is 0.5 parts by weight or 6 parts by weight, which can extend the service life of the diaphragm 10.

[0075] According to one embodiment of the present invention, other additives include at least one of stearic acid, ultraviolet absorber, and color paste. By adding different additives, the film layer can have different functions. For example, stearic acid, as a release agent, can improve lubrication during rubber compounding and product demolding during production. Color paste can dye the rubber; conventional HXNBR is a colored rubber with low aesthetic appeal. By adding color paste, diaphragms 10 of different colors can be made, increasing aesthetics. Furthermore, since the unsaturated carbon-carbon double bonds in HXNBR are not completely hydrogenated, they will degrade under ultraviolet radiation. By adding ultraviolet absorber, the film layer can have ultraviolet absorption function.

[0076] Optionally, the thickness of the compounded carboxylated nitrile rubber membrane layer is 25 μm to 300 μm. Using a compounded carboxylated nitrile rubber membrane layer within this thickness range facilitates the fabrication of the diaphragm 10 and its use, enabling the diaphragm 10 to possess good acoustic performance, waterproof performance, and a lighter weight. Optionally, the thickness of the compounded carboxylated nitrile rubber membrane layer can be 25 μm, 30 μm, 50 μm, 60 μm, 100 μm, 200 μm, or 300 μm.

[0077] In some specific embodiments of the present invention, the diaphragm 10 is formed as a single-layer structure comprising only one layer of compounded hydrogenated carboxylated nitrile rubber film; or, the diaphragm 10 is formed as a composite layer structure, comprising at least one layer of compounded hydrogenated carboxylated nitrile rubber film.

[0078] In other words, the diaphragm 10 according to the embodiments of the present invention can be a single-layer film structure or a film structure composed of multiple film layers, as long as it meets the requirement that the diaphragm 10 contains at least one layer of compounded hydrogenated carboxylated nitrile rubber film layer. Therefore, the diaphragm 10 according to the embodiments of the present invention can meet the product requirements of different sound-generating devices. When the diaphragm 10 is formed as a composite layer structure, one layer can be the compounded hydrogenated carboxylated nitrile rubber film layer of the present invention, and the remaining layers can be TPEE material layers, AEM material layers, etc.

[0079] Furthermore, the diaphragm 10 provided by this invention can be configured into a sound-generating device of any structure. For example... Figure 2 As 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.

[0080] In other specific embodiments of the present invention, such as Figure 3 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 10 of the above embodiment.

[0081] 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.

[0082] 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.

[0083] The electronic device according to the present invention includes the sound-generating device of the above embodiments, and the sound-generating device adopts the diaphragm of the above embodiments. Since the diaphragm of the above embodiments of the present invention has the above-mentioned technical effects, the electronic device according to the present invention also has the corresponding technical effects, that is, the waterproof capability of the diaphragm 10 can meet the waterproof requirements of the sound-generating device.

[0084] The diaphragm 10 and the sound-generating device of the present invention will be described in detail below with reference to specific embodiments.

[0085] Example 1

[0086] The mixture is made from carboxylated nitrile rubber (100 parts by weight), hexamethylenediamine (vulcanizing agent, 4 parts by weight), modified imidazole (vulcanization accelerator, 3 parts by weight), carbon black (reinforcing agent, carbon black particle size 30 nm, 40 parts by weight), and aging agent 264 (anti-aging agent, 3 parts by weight).

[0087] Comparative Example 1

[0088] The mixture is made from carboxylated nitrile rubber (100 parts by mass), hexamethylenediamine (vulcanizing agent, 4 parts by mass), modified imidazole (vulcanization accelerator, 3 parts by mass), carbon black (reinforcing agent, carbon black particle size 30nm, 1 part by mass), and aging agent 264 (anti-aging agent, 3 parts by mass).

[0089] The only difference between Comparative Example 1 and Example 1 is the content of carbon black. The carbon black content in Example 1 is 40 parts by mass, while the carbon black content in Comparative Example 1 is 1 part by mass.

[0090] Comparative Example 2

[0091] The mixture is made from carboxylated nitrile rubber (100 parts by mass), hexamethylenediamine (vulcanizing agent, 4 parts by mass), modified imidazole (vulcanization accelerator, 3 parts by mass), carbon black (reinforcing agent, carbon black particle size 30nm, 100 parts by mass), and aging agent 264 (anti-aging agent, 3 parts by mass).

[0092] Compared with Example 1, Comparative Example 2 differs only in the content of carbon black. The carbon black content in Example 1 is 40 parts by mass, while the carbon black content in Comparative Example 2 is 100 parts by mass.

[0093] Comparative Example 3

[0094] The mixture is made from carboxylated nitrile rubber (100 parts by mass), hexamethylenediamine (vulcanizing agent, 4 parts by mass), modified imidazole (vulcanization accelerator, 3 parts by mass), carbon black (reinforcing agent, carbon black particle size 150 nm, 40 parts by mass), and aging agent 264 (anti-aging agent, 3 parts by mass).

[0095] Compared with Example 1, Comparative Example 3 differs only in the particle size of the carbon black. The carbon black in Example 1 has a particle size of 30 nm, while the carbon black in Comparative Example 3 has a particle size of 150 nm.

[0096] Comparative Example 4

[0097] A thermoplastic polyester elastomer (TPEE) composite diaphragm is used, and the composite diaphragm has a three-layer structure. The three-layer structure consists of two surface layers and one intermediate layer, with the intermediate layer located between the two surface layers. Both surface layers are TPEE layers, and each surface layer is 15μm thick. The intermediate layer is a polyacrylate pressure-sensitive adhesive film, and the thickness of the intermediate layer is 20μm.

[0098] Comparative Example 5

[0099] The mixture is made from AEM raw rubber (100 parts by weight), hexamethylenediamine (vulcanizing agent, 4 parts by weight), modified imidazole (vulcanization accelerator, 3 parts by weight), carbon black (reinforcing agent, carbon black particle size 30 nm, carbon black content 30 parts by weight), and aging agent 264 (anti-aging agent, 3 parts by weight).

[0100] Compared with Example 1, Comparative Example 5 uses carboxylated nitrile rubber instead of AEM rubber; the carbon black content in Example 1 is 40 parts by mass, while the carbon black content in Comparative Example 5 is 30 parts by mass.

[0101] In addition, during the preparation of the diaphragm, Examples 1, 1, 2, 3 and 5 were vulcanized at 200°C for 10 minutes and 3 MPa, respectively, to produce single-layer diaphragms and diaphragms of 0.1 mm.

[0102] Furthermore, Examples 1 and Comparative Examples 1 to 5 were all fabricated based on diaphragms with similar F0 values.

[0103] The waterproof performance of the diaphragms obtained in Example 1 and Comparative Examples 1 to 5 was tested below. The test results are shown in Table 3 below, and plotted based on Table 3. Figure 4 This improves intuitiveness.

[0104] Table 3. Waterproof test data of the diaphragms in the examples and comparative examples

[0105]

[0106] The following is a combination of Table 3 and... Figure 3 The experimental results were analyzed.

[0107] First, Example 1 is compared with Comparative Example 1 and Comparative Example 2, respectively.

[0108] The carbon black content in Comparative Example 1 was 1 part by mass, the carbon black content in Example 1 was 40 parts by mass, and the carbon black content in Comparative Example 2 was 100 parts by mass. The tensile strength of the membrane in Comparative Example 1 was 12 MPa, the tensile strength of the membrane in Example 1 was 30 MPa, and the tensile strength of the membrane in Comparative Example 2 was 55 MPa. It can be seen that the tensile strength of the membrane increases with the increase of carbon black content. The elastic recovery rate of the membrane in Comparative Example 1 was 98%, the elastic recovery rate of the membrane in Example 1 was 93%, and the elastic recovery rate of the membrane in Comparative Example 2 was 62%. It can be seen that the elastic recovery rate of the membrane decreases with the increase of carbon black content.

[0109] Furthermore, the sound quality of Comparative Example 1 after 150m waterproofing was 83%, the sound quality of Comparative Example 2 after 150m waterproofing was 75%, while the sound quality of the diaphragm in Example 1 after 150m waterproofing was 100%. It can be seen that whether the amount of carbon black is increased or decreased, the sound quality decreases after waterproofing.

[0110] In addition, the amount of carbon black used in Comparative Example 1 was relatively small, resulting in insufficient strength and easy diaphragm breakage. Consequently, the diaphragm of Comparative Example 1 had a breakage rate of 10% at 150m of waterproofing.

[0111] Next, Example 1 and Comparative Example 2 will be compared.

[0112] The diaphragm in Example 1 had an elastic recovery rate of 93%, and the sound quality was 100% after being waterproofed for 150m. In Comparative Example 2, the diaphragm had an elastic recovery rate of 62%, and the sound quality was 75% after being waterproofed for 150m. It is evident that as the amount of carbon black increases, the elastic recovery rate of the diaphragm decreases, resulting in poor rebound of the diaphragm product, the appearance of surround deformation, and a consequent decrease in sound quality.

[0113] Furthermore, Example 1 and Comparative Example 3 were compared.

[0114] The carbon black in Example 1 had a particle size of 30 nm, while the carbon black in Comparative Example 3 had a particle size of 150 nm. The tensile strength of the diaphragm in Example 1 was 30 MPa, while that of the diaphragm in Comparative Example 3 was 15 MPa. The elastic recovery rate of the diaphragm in Example 1 was 93%, while that of the diaphragm in Comparative Example 3 was 77%. The diaphragm in Example 1 had a 0% breakage rate after being waterproofed for 150 μm, while that of the diaphragm in Comparative Example 3 was 30%. The sound quality of the diaphragm in Example 1 was 100% after being waterproofed for 150 μm, while that of the diaphragm in Comparative Example 3 was 50%. It is evident that as the particle size of the carbon black increases, the tensile strength of the diaphragm decreases, the elastic recovery rate deteriorates, the breakage rate of the diaphragm increases, and the sound quality decreases after waterproofing.

[0115] Furthermore, as can be seen from Comparative Example 4, because the TPEE composite film requires adhesive bonding, even with high strength and good resilience, the diaphragm will still delaminate, leading to complete failure.

[0116] As can be seen from Comparative Example 5, the strength of AEM is low, the waterproof reliability shows the phenomenon of membrane rupture, and due to the poor resilience of the diaphragm, the diaphragm deforms after the waterproof reliability is achieved, resulting in a low sound quality of the diaphragm.

[0117] In summary, the diaphragm 10 in this embodiment of the invention is prepared by using a compounded carboxylated nitrile rubber membrane layer. Carbon black is used as a reinforcing agent in the compounded carboxylated nitrile rubber membrane layer, and the content of carbon black is 15 parts by mass to 75 parts by mass. The particle size of carbon black is less than 60 nm, which can ensure that the diaphragm 10 has high tensile strength, large elastic recovery rate, good waterproof effect and good acoustic performance.

[0118] 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, characterized in that, The diaphragm comprises a compounded carboxylated nitrile rubber film layer, which is composed of carboxylated nitrile raw rubber, vulcanizing agent, reinforcing agent, antioxidant, and other additives. The reinforcing agent is carbon black. The content of the carboxylated nitrile raw rubber is 100 parts by weight, and the content of the carbon black is 15 to 75 parts by weight, with a particle size less than 60 nm. The carboxyl group content in the compounded carboxylated nitrile rubber film layer is 0.2 wt% to 6 wt%. The acrylonitrile group content in the carboxyl groups of the compounded carboxylated nitrile rubber film layer is 10 wt% to 35 wt%. The tensile strength of the compounded carboxylated nitrile rubber film layer is ≥15 MPa, and the elastic recovery rate is ≥80%. The waterproof rating of the diaphragm is not less than 15 ATM.

2. The diaphragm according to claim 1, characterized in that, The vulcanizing agent is at least one of amine vulcanizing agents, epoxy vulcanizing agents, sulfur, and peroxides.

3. The diaphragm according to claim 2, characterized in that, The content of the vulcanizing agent is 1 part by weight to 20 parts by weight.

4. The diaphragm according to claim 1, characterized in that, The other additives contain a vulcanization accelerator, which is at least one of the following: tertiary ammonium compounds, substituted ureas, phenols, imidazoles, metal acetylacetone salts, boron trifluoride complex thiazoles, sulfenamides, thiurams, thioureas, dithiocarbamates, aldehyde amines, arsenides, and xanthates.

5. The diaphragm according to claim 4, characterized in that, The content of the vulcanization accelerator is 0.1 parts by weight to 8 parts by weight.

6. The diaphragm according to claim 1, characterized in that, The antioxidant is at least one of the following: antioxidant 1010, antioxidant 2, antioxidant 6, antioxidant 4, antioxidant 1076, antioxidant 168, antioxidant RD, antioxidant AW, antioxidant DD, antioxidant BLE, antioxidant 4010, 4010NA, 4020, 4030, 4040, antioxidant DNP, antioxidant H, antioxidant A, antioxidant D, antioxidant SP, antioxidant 264, antioxidant 2246, antioxidant 2246-S, antioxidant NBC, and antioxidant MB.

7. The diaphragm according to claim 6, characterized in that, The content of the antioxidant is 0.5 parts by weight to 6 parts by weight.

8. The diaphragm according to claim 1, characterized in that, The other additives include at least one of stearic acid, ultraviolet absorber, and color paste.

9. The diaphragm according to any one of claims 1-8, characterized in that, The diaphragm is formed as a single-layer structure comprising only one layer of the compounded carboxylated butadiene-acrylonitrile rubber film layer; Alternatively, the diaphragm may be formed as a composite layer structure, the diaphragm comprising at least one layer of the compounded carboxylated nitrile rubber film.

10. A sound-generating device, characterized in that, The diaphragm includes any one of claims 1 to 9.

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