Diaphragm and sound emitting device

Abstract

The application discloses a vibrating diaphragm and a sound production device, and relates to the field of sound production devices. The vibrating diaphragm comprises a mixing type carboxyl nitrile rubber film layer, which is formed by mixing carboxyl nitrile raw rubber, vulcanizing agents, fillers, anti-aging agents and other additives, wherein the content of acrylonitrile in the carboxyl nitrile raw rubber is 20wt%-40wt%, and the content of carboxyl is 3wt%-6wt%; and the oil absorption rate of the mixing type carboxyl nitrile rubber film layer is less than or equal to 5% after 96 hours in a 65 DEG C environment. The vibrating diaphragm is prepared by using the mixing type carboxyl nitrile rubber film layer, the content of acrylonitrile in the carboxyl nitrile raw rubber is 20wt%-40wt%, and the content of carboxyl is 3wt%-6wt%. The carboxyl nitrile raw rubber of the embodiment contains a large number of polar groups such as cyano groups (-C≡N) and carboxyl groups (-COOH), has good oil resistance, and the oil absorption rate of the mixing type carboxyl nitrile rubber film layer is less than or equal to 5% after 96 hours in a 65 DEG C environment. Therefore, the oil resistance of the vibrating diaphragm is improved, and the acoustic performance stability is also improved.

Description

TECHNICAL FIELD

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

[0002] The sound emitting devices of existing wearable products such as earphones, smart watches, smart bracelets, VR and AR products, etc. mostly use thermoplastic elastomers or rubber.

[0003] However, the diaphragms of the above products have poor resistance to oil, and the diaphragms can absorb oil in the oil-based substances, deform and swell, resulting in a decline in the acoustic performance of the diaphragm product itself, and seriously affecting the service life of the electronic product and the user experience. SUMMARY

[0004] An object of the present application is to provide a diaphragm that can solve the technical problem of poor resistance to oil of the diaphragm in the prior art.

[0005] Another object of the present application is to provide a sound emitting device having the above diaphragm.

[0006] 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 100 parts by mass, a vulcanizing agent, a filler, an antioxidant and other additives, wherein the content of acrylonitrile in the carboxyl nitrile raw rubber is 20wt% to 40wt%, and the content of carboxyl is 3wt% to 6wt%, and the oil absorption rate of the mixed carboxyl nitrile rubber film layer after 96h in a 65℃ environment is ≤5%.

[0007] Optionally, the vulcanizing agent is at least one of amine, epoxy, metal oxide, metal peroxide, sulfur, peroxide.

[0008] Optionally, the content of the vulcanizing agent is 8 parts by mass to 20 parts by mass.

[0009] Optionally, the other additives include a vulcanization accelerator, and the vulcanization accelerator is at least one of tertiary ammonium, substituted urea, phenol, imidazole, acetylacetone metal salt, boron trifluoride complex thiazole, sulfenamide, thiuram, thiourea, dithio carbamate, aldehyde amine, mercaptobenzimidazole, xanthate, triallyl.

[0010] Optionally, the content of the vulcanization accelerator is 0.1-8 parts by mass.

[0011] Optionally, the anti-aging agent is at least one of antioxidant 1010, antioxidant 2, antioxidant 6, antioxidant 4, antioxidant 1076, antioxidant 168, anti-aging agent RD, anti-aging agent AW, anti-aging agent DD, anti-aging agent BLE, anti-aging agent 4010, 4010NA, 4020, 4030, 4040, anti-aging agent DNP, anti-aging agent H, anti-aging agent A, anti-aging agent D, anti-aging agent SP, anti-aging agent 264, anti-aging agent 2246, anti-aging agent 2246-S, anti-aging agent NBC, anti-aging agent MB.

[0012] Optionally, the content of the anti-aging agent is 0.5-6 parts by mass.

[0013] Optionally, the filler is at least one of carbon black, white carbon black, talc, calcium carbonate, magnesium carbonate, dolomite, barium sulfate, zinc sulfide, aluminum powder, graphite, titanium dioxide, lithopone, phenolic resin, petroleum resin, styrene resin.

[0014] Optionally, the content of the filler is 5-100 parts by mass.

[0015] Optionally, the other auxiliary agent includes at least one of stearic acid, ultraviolet absorber, color paste, plasticizer.

[0016] 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, and the diaphragm includes at least one layer of the mixed carboxyl nitrile rubber film layer.

[0017] According to a second aspect of the present application, there is provided a sound generating device including the diaphragm as described above.

[0018] One technical effect of the present application is that the diaphragm according to the embodiments of the present application is prepared by the mixed carboxyl nitrile rubber film layer, the content of acrylonitrile in the carboxyl nitrile rubber is 20wt%-40wt%, and the content of carboxyl is 3wt%-6wt%. The carboxyl nitrile rubber contains a large amount of polar groups such as cyano (-C≡N) and carboxyl (-COOH), and has good oil resistance. The oil absorption rate of the mixed carboxyl nitrile rubber film layer is ≤5% after 96h in a 65℃ environment, the resistance to common skin care products is greatly improved under the same conditions, and the stability of the acoustic performance is also improved.

[0019] Other features and advantages of the present application will become apparent from the following detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] 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.

[0021] Figure 1 Structure diagram of a diaphragm according to an embodiment of the present application;

[0022] Figure 2 Partial sectional view of a sound emitting device according to an embodiment of the present application;

[0023] Figure 3 Partial sectional view of a sound emitting device according to another embodiment of the present application;

[0024] Figure 4 Comparative diagram of oil absorption, product defect rate and low temperature diaphragm breaking rate of the examples and comparative examples.

[0025] Reference numerals:

[0026] Diaphragm 10; main body portion 11; conductive portion 12;

[0027] Voice coil 20; first diaphragm 21; second diaphragm 22. DETAILED DESCRIPTION

[0028] 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.

[0029] 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.

[0030] 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.

[0031] In all of the examples shown and discussed herein, any specific values should be interpreted as illustrative only and not as a limitation. Thus, other examples of exemplary embodiments can have different values.

[0032] It should be noted that like numerals and letters refer to like items throughout the drawings, and as a result, once an item is defined in one drawing, it need not be discussed further in subsequent drawings.

[0033] The diaphragm and sound emitting device according to embodiments of the present application will now be described in detail below with reference to the specific drawings. In the drawings, Figures 1 to 3As shown, the sound generating device can be a loudspeaker unit, which can include a magnetic circuit system, a diaphragm 10, and a voice coil 20 arranged on the diaphragm 10, and an end of the voice coil 20 away from the diaphragm 10 is arranged in a magnetic gap of the magnetic circuit system. When the loudspeaker unit is in operation, an electric current is passed through the voice coil 20, and the voice coil 20 reciprocates under the action of the magnetic force to drive the diaphragm 10 to vibrate and generate sound.

[0034] The diaphragm 10 according to the embodiment of the present application comprises a mixed carboxyl nitrile rubber film layer, which is mixed from carboxyl nitrile raw rubber 100 parts by mass, a vulcanizing agent, a filler, an antioxidant, and other additives. In the carboxyl nitrile raw rubber, the content of acrylonitrile is 20wt% to 40wt%, and the content of carboxyl is 3wt% to 6wt%. The oil absorption rate of the mixed carboxyl nitrile rubber film layer after 96 hours in an environment of 65°C is less than or equal to 5%.

[0035] In other words, the material of the diaphragm 10 according to the embodiment of the present application comprises carboxyl nitrile rubber. Specifically, the diaphragm 10 comprises a mixed carboxyl nitrile rubber film layer, which is mixed from carboxyl nitrile raw rubber, a vulcanizing agent, a filler, an antioxidant, and other additives.

[0036] In the carboxyl nitrile raw rubber, the content of acrylonitrile is 20wt% to 40wt%, and the content of carboxyl is 3wt% to 6wt%.

[0037]

[0038] In formula (I), a, b, c, and d are natural numbers. In formula (I), the original polymerization monomer of X can be an ethylenically unsaturated monocarboxylic acid or an ethylenically unsaturated dicarboxylic acid. The ethylenically unsaturated monocarboxylic acid can be acrylic acid, methacrylic acid, ethyl acrylate, crotonic acid, cinnamic acid, etc. The ethylenically unsaturated dicarboxylic acid can be fumaric acid, maleic acid, glutaconic acid, allyl malonic acid, mesaconic acid, toconic acid, itaconic acid, and endoconic acid, etc.

[0039] In the carboxyl nitrile raw rubber, the content of acrylonitrile is 20wt% to 40wt%, and the content of carboxyl is 3wt% to 6wt%. The oil absorption rate of the mixed carboxyl nitrile rubber film layer after 96 hours in an environment of 65°C is less than or equal to 5%. By adopting the above limitations on the carboxyl nitrile raw rubber and the mixed carboxyl nitrile rubber film layer, the oil resistance of the diaphragm 10 prepared can be improved, and the acoustic performance stability of the diaphragm 10 can also be improved.

[0040] It should be noted that the nitrile group is a strong polar group with high electronegativity. When the content of acrylonitrile is less than 20wt%, the molecular chain of the mixed carboxyl butyl nitrile rubber film layer has good flexibility, low intermolecular force and low glass transition temperature, resulting in low tensile strength and poor resilience, which cannot meet the demand. When the content of acrylonitrile is greater than 40wt%, with the increase of the content of acrylonitrile, the polarity of the mixed carboxyl butyl nitrile rubber film layer increases, the flexibility of the molecular chain decreases, the interaction force between the molecular chains increases, the chain segment movement is difficult, the glass transition temperature is higher, the double bond content in the molecular chain decreases, the saturation degree increases, the oil resistance, air tightness, relative density, vulcanization speed, tensile strength performance are improved, and the processability and cold resistance are decreased, the resilience performance is decreased. Especially when the content of acrylonitrile block is too high, the diaphragm 10 prepared therefrom is easy to become hard and brittle in low temperature extreme environment, increasing the risk of membrane rupture.

[0041] In addition, the carboxyl group is also a polar group. When the content of carboxyl group is less than 3wt%, the polarity and crosslinking density of the mixed carboxyl butyl nitrile rubber film layer are too small, and the oil resistance is poor; when the content of carboxyl group is greater than 6wt%, the crosslinking density and polarity are too high, the Tg is higher, and the low temperature reliability is prone to membrane rupture. It should be noted that first, the carboxyl group itself has polarity, which improves the oil resistance of the mixed carboxyl butyl nitrile rubber film layer; second, by adding carboxyl group, the crosslinking density can be increased, and the carboxyl group can play a crosslinking role, thereby further improving the oil resistance; third, the carboxyl group and the acrylonitrile are both polar groups, and the compatibility between them is better, so that the intermolecular gap between acrylonitrile and carboxyl group is smaller, and the oil resistance is further better. It can be seen that by limiting the content of carboxyl group, the crosslinking degree can be affected, thereby affecting the oil resistance. And by containing acrylonitrile and carboxyl group at the same time, the polarity of acrylonitrile and carboxyl group is higher, the binding force between groups is stronger, the intermolecular gap is smaller, and the oil resistance is also better.

[0042] The glass transition temperatures of carboxyl butyl nitrile rubber with different acrylonitrile contents were measured, and the measurement results are shown in Table 1 below. The glass transition temperatures of carboxyl butyl nitrile rubber with different carboxyl contents were measured, and the measurement results are shown in Table 2 below.

[0043] Table 1. Tg of carboxyl butyl nitrile rubber with different acrylonitrile contents

[0044]

[0045] Table 2. Tg of carboxyl butyl nitrile rubber with different carboxyl contents

[0046] Carboxyl content / wt% 1 3 5 10 Tg / °C -45 -33 -27 20

[0047] It can be seen that the content of acrylonitrile and carboxyl in the carboxyl butyronitrile rubber green rubber affects the oil resistance of the mixed carboxyl butyronitrile rubber film layer. Alternatively, the content of acrylonitrile in the carboxyl butyronitrile rubber green rubber is 20wt%, 22wt%, 25wt%, 30wt%, 35wt%, 40wt% and the content of carboxyl is 3wt%, 3.5wt%, 4wt%, 5wt%, 6wt%. It should be noted that the content of acrylonitrile and the content of carboxyl in the present application meet the content range of acrylonitrile and the content range of carboxyl. If the content of acrylonitrile is within the range of 20wt% to 40wt% in the present application, but the content of carboxyl is less than 3wt%, it will result in insufficient crosslinking density. If the content of acrylonitrile is within the range of 20wt% to 40wt% in the present application, but the content of carboxyl is greater than 6wt%, it will result in too high crosslinking density, which makes the diaphragm 10 poor in toughness and prone to breakage. If the content of carboxyl is within the range of 3wt% to 6wt% in the present application, but the content of acrylonitrile is less than 20wt%, it will result in low oil resistance of the diaphragm 10. If the content of carboxyl is within the range of 3wt% to 6wt% in the present application, but the content of acrylonitrile is greater than 40wt%, although its oil resistance, air tightness, relative density, vulcanization speed and tensile strength performance are improved, the processability and cold resistance of the diaphragm 10 are decreased, and the diaphragm 10 will not be used.

[0048] Therefore, according to the diaphragm 10 of the embodiment of the present application, the mixed carboxyl butyronitrile rubber film layer is prepared, the oil absorption rate of the mixed carboxyl butyronitrile rubber film layer is less than or equal to 5% after 96h in a 65℃ environment, the content of acrylonitrile in the carboxyl butyronitrile rubber green rubber is 20wt% to 40wt%, and the content of carboxyl is 3wt% to 6wt%. The carboxyl butyronitrile rubber green rubber of the embodiment of the present application contains a large amount of polar groups such as cyano (-C≡N) and carboxyl (-COOH), has good oil resistance, greatly improves the tolerance to common skin care products under the same conditions, and also improves the stability of acoustic performance.

[0049] According to an embodiment of the present application, the vulcanizing agent is at least one of amine, epoxy, metal oxide, metal peroxide, sulfur, peroxide and the like, for example, the vulcanizing agent is bisphenol A epoxy resin. The amine crosslinking agent includes at least one of hexamethylene diamine, hexamethylene diamine salt, hexamethylene diamine carbamate, triethylene tetramine, sub-base diphenylamine and di-ortho-toluene guanidine and the like. The use of the above vulcanizing agent is conducive to ensuring the crosslinking density.

[0050] Alternatively, the functional group of the epoxy crosslinking agent is not less than two. Alternatively, the epoxy crosslinking agent includes at least one of phenol glycidyl ether epoxy resin, glycidyl ester epoxy resin, glycidyl amine epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin and the like.

[0051] In some embodiments of the present application, the content of the vulcanizing agent is 8-20 parts by mass, which increases the crosslinking density, reduces the intermolecular voids, and improves the oil resistance of the diaphragm 10. It should be noted that if the content of the vulcanizing agent is less than 8 parts by mass, the crosslinking density is insufficient; if the content of the vulcanizing agent is greater than 20 parts by mass, the porosity is too large, which affects the oil resistance of the diaphragm 10. Alternatively, the content of the vulcanizing agent is 8 parts by mass, 10 parts by mass, 12 parts by mass, 15 parts by mass, 20 parts by mass, etc.

[0052] According to one embodiment of the present application, the other auxiliary agent includes a vulcanization accelerator, and the vulcanization accelerator is at least one of a tertiary ammonium type, a substituted urea type, a phenol type, an imidazole type, an acetylacetone metal salt type, a boron trifluoride complex thiazole type, a sulfenamide type, a thiuram type, a thiourea type, a dithio carbamate salt type, an aldehyde amine type, an aryl type, a xanthate type, a triallyl type, etc. By using the above-mentioned vulcanization accelerator, the vulcanization speed is improved.

[0053] In some embodiments of the present application, the content of the vulcanization accelerator is 0.1-8 parts by mass, which can promote vulcanization while ensuring the elasticity and brittleness requirements of the diaphragm 10. If the content of the vulcanization accelerator is less than 0.1 parts by mass, it is difficult to promote vulcanization; if the content of the vulcanization accelerator is greater than 8 parts by mass, the vulcanization speed is too fast, the diaphragm 10 is too brittle, and cannot meet the use requirements. Alternatively, the content of the vulcanization accelerator is 0.1 parts by mass, 1 parts by mass, 2 parts by mass, 5 parts by mass, 6 parts by mass, and 8 parts by mass, etc.

[0054] According to one embodiment of the present application, 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, antioxidant MB, etc. By using the above-mentioned antioxidant, the service life of the diaphragm 10 can be extended.

[0055] In some specific embodiments of the present application, the content of the anti-aging agent is 0.5-6 parts by mass, which not only prolongs the service life of the diaphragm 10, but also ensures the appearance of the diaphragm 10. It should be noted that if the content of the anti-aging agent is less than 0.5 parts by mass, i.e., the amount of the anti-aging agent added is too small, it is difficult to achieve the effect of prolonging the service life; if the content of the anti-aging agent is greater than 6 parts by mass, i.e., the amount of the anti-aging agent added is too much, since it cannot be well miscible with the elastomer, it is difficult to disperse uniformly, resulting in a decrease in the mechanical properties of the diaphragm 10 material, and it is easy to precipitate on the surface of the diaphragm 10 over time. Alternatively, the content of the anti-aging agent is 0.5 parts by mass, 1 part by mass, 3 parts by mass, 4 parts by mass, 5 parts by mass, 6 parts by mass, etc.

[0056] According to an embodiment of the present application, the filler is at least one of carbon black, white carbon black, talc, calcium carbonate, magnesium carbonate, dolomite, barium sulfate, zinc sulfide, aluminum powder, graphite, titanium dioxide, lithopone, phenolic resin, petroleum resin, styrene resin, etc. By using the above-mentioned filler, the mechanical strength of the diaphragm 10 can be improved.

[0057] The filler will be described below taking carbon black as an example.

[0058] Carbon black is an amorphous structure, and the particles form aggregates through physical and chemical bonding between each other. The primary structure of carbon black is composed of aggregates, and there is a van der Waals force or hydrogen bond between the aggregates, which can aggregate into a spatial network structure, i.e., the secondary structure of carbon black. The surface of carbon black has groups such as hydrogen, carboxyl, lactone, free radical, and quinone groups that can undergo substitution, reduction, oxidation, etc. When carbon black is added to XNBR, due to the strong interaction between the surface of carbon black and the carboxyl nitrile rubber interface, when the material is stressed, the molecular chain is more likely to slide on the surface of carbon black, but it is not easy to separate from carbon black. The elastomer and carbon black form a strong and sliding bond, and the mechanical strength of the diaphragm 10 is increased.

[0059] According to an embodiment of the present application, the content of the filler is 5-100 parts by mass. By using the filler in this amount, the carbon black and the carboxyl nitrile rubber interface can have a strong interaction. When the amount of carbon black is less than 5 parts by mass, it is difficult to play a role in enhancing the mechanical strength, and the tensile strength of the carboxyl nitrile rubber itself is low; when the amount of carbon black is greater than 100 parts by mass, the elongation at break of the diaphragm 10 decreases. Alternatively, the content of the filler is 5 parts by mass, 15 parts by mass, 20 parts by mass, 30 parts by mass, 50 parts by mass, 60 parts by mass, 70 parts by mass, 80 parts by mass, 100 parts by mass, etc.

[0060] In some embodiments of the present application, the other auxiliary agents include at least one of stearic acid, ultraviolet absorber, color paste, plasticizer, etc. Among them, by adding different auxiliary agents, the diaphragm 10 can have different functions. For example, stearic acid as a release agent can improve the lubricity in the mixing process and the release of the diaphragm 10 product in the production process. The color paste can dye the carboxyl nitrile rubber, and the conventional carboxyl nitrile rubber is colored rubber, which has low aesthetic appearance. By adding color paste, the diaphragm 10 of different colors can be made to increase the aesthetic appearance. In addition, since the unsaturated carbon-carbon double bond in the carboxyl nitrile rubber is not completely hydrogenated, it will be degraded under ultraviolet radiation. By adding an ultraviolet absorber, the diaphragm 10 can have ultraviolet absorption function.

[0061] According to one embodiment of the present application, the thickness of the mixed carboxyl nitrile rubber film layer is 25 μm to 300 μm. By using the mixed carboxyl nitrile rubber film layer with the thickness in this range, the preparation and use of the diaphragm 10 are facilitated.

[0062] In some embodiments of the present application, the diaphragm 10 is formed as a single-layer structure including only one layer of mixed carboxyl nitrile rubber film layer; or, the diaphragm 10 is formed as a composite layer structure, and the diaphragm 10 includes at least one layer of mixed carboxyl nitrile rubber film layer.

[0063] That is, the diaphragm 10 according to the embodiments of the present application can be a single-layer film layer structure or a film layer structure composed of multiple film layers, as long as it meets the requirement that the diaphragm 10 contains at least one layer of mixed carboxyl nitrile rubber film layer. Thus, the diaphragm 10 according to the embodiments of the present application can meet the product requirements of different sound generating devices.

[0064] In addition, the diaphragm 10 provided by the present application can be composed into a sound generating device of any structure. As shown in Figure 2 The sound generating device according to the embodiments of the present application includes a shell, a magnetic circuit system arranged in the shell, and a vibration system cooperating with the magnetic circuit system. The vibration system includes the diaphragm 10 and the voice coil 20 combined on one side of the diaphragm 10. The magnetic circuit system drives the voice coil 20 to vibrate to drive the diaphragm 10 to generate sound. The diaphragm 10 is the diaphragm 10 of the above-mentioned embodiments. Specifically, when the sound generating device is working, the voice coil 20 is energized and vibrates up and down under the action of the magnetic field force of the magnetic circuit system to drive the diaphragm 10 to vibrate, and the diaphragm 10 can generate sound when it vibrates. The sound generating device includes a diaphragm 10 prepared by the above-mentioned embodiments of the present application.

[0065] In some other embodiments of the present application, as shown in Figure 3As shown, according to the sound production device according to the embodiment of the present application, the sound production device comprises a shell, a magnetic circuit system and a vibration system arranged in the shell, the vibration system comprises a voice coil 20, a first diaphragm 21 and a second diaphragm 22, the top of the voice coil 20 is connected with the first diaphragm 21, the magnetic circuit system drives the voice coil 20 to vibrate to drive the first diaphragm 21 to produce sound, the two ends of the second diaphragm 22 are respectively connected with an external circuit and the bottom of the voice coil 20, and the second diaphragm 22 is the diaphragm of the above-mentioned embodiment.

[0066] That is, the sound production device according to the embodiment of the present application can further comprise two diaphragms prepared by the diaphragm of the above-mentioned embodiment of the present application, i.e. the first diaphragm 21 and the second diaphragm 22, the first diaphragm 21 can be used for vibration sound production, and the second diaphragm 22 can be used for balancing the vibration of the voice coil 20. Specifically, when the sound production device works, the voice coil 20 is electrified and vibrates up and down under the action of the magnetic field force of the magnetic circuit system to drive the first diaphragm 21 to vibrate, and the first diaphragm 21 can produce sound when vibrating. The second diaphragm 22 can also vibrate up and down with the voice coil 20, and since the two ends of the second diaphragm 22 are respectively connected with 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 can prevent the voice coil 20 from deviating, thereby improving the sound production effect of the sound production device.

[0067] It should be noted that the first diaphragm 21 and the second diaphragm 22 can both adopt the diaphragm 10 of the above-mentioned embodiment of the present application, or one of the first diaphragm 21 and the second diaphragm 22 can adopt the diaphragm 10 of the above-mentioned embodiment of the present application, and the present application does not make specific limitation thereon.

[0068] The electronic device according to the embodiment of the present application comprises the sound production device of the above-mentioned embodiment, and the sound production device adopts the diaphragm of the above-mentioned embodiment. Since the diaphragm according to the above-mentioned embodiment of the present application has the above-mentioned technical effect, the electronic device according to the embodiment of the present application also has corresponding technical effect, i.e. good oil resistance, under the same conditions, greatly improved resistance to common skin care products, and improved stability of acoustic performance.

[0069] The diaphragm and the sound production device of the present application will be described in detail below in combination with specific embodiments.

[0070] Embodiment 1

[0071] Carboxyl nitrile rubber, bisphenol A epoxy resin, modified imidazole, carbon black and aging agent 264 are mixed.

[0072] The content of the carboxyl nitrile rubber is 100 parts by mass; the carboxyl content of the carboxyl nitrile rubber is 4 wt%, and the acrylonitrile content is 35 wt%; the bisphenol A epoxy resin is used as a vulcanizing agent, the epoxy value of which is 435 g / eq, and the content is 6 parts by mass; the modified imidazole is used as a vulcanization accelerator, the content is 1 part by mass; the carbon black is used as a filler, the content is 50 parts by mass; and the antioxidant 264 is used as an antioxidant, the content is 3 parts by mass.

[0073] Comparative Example 1

[0074] The carboxyl nitrile rubber, the bisphenol A epoxy resin, the modified imidazole, the carbon black and the antioxidant 264 are mixed.

[0075] The content of the carboxyl nitrile rubber is 100 parts by mass; the carboxyl content of the carboxyl nitrile rubber is 0.5 wt%, and the acrylonitrile content is 10 wt%; the bisphenol A epoxy resin is used as a vulcanizing agent, the epoxy value of which is 435 g / eq, and the content is 6 parts by mass; the modified imidazole is used as a vulcanization accelerator, the content is 1 part by mass; the carbon black is used as a filler, the content is 50 parts by mass; and the antioxidant 264 is used as an antioxidant, the content is 3 parts by mass.

[0076] Comparative Example 1 and Example 1 are compared, and the difference lies in that the carboxyl content of the carboxyl nitrile rubber in Example 1 is 4 wt%, and the acrylonitrile content is 35 wt%; the carboxyl content of the carboxyl nitrile rubber in Comparative Example 1 is 0.5 wt%, and the acrylonitrile content is 10 wt%.

[0077] Comparative Example 2

[0078] The carboxyl nitrile rubber, the bisphenol A epoxy resin, the modified imidazole, the carbon black and the antioxidant 264 are mixed.

[0079] The content of the carboxyl nitrile rubber is 100 parts by mass; the carboxyl content of the carboxyl nitrile rubber is 0.5 wt%, and the acrylonitrile content is 35 wt%; the bisphenol A epoxy resin is used as a vulcanizing agent, the epoxy value of which is 435 g / eq, and the content is 6 parts by mass; the modified imidazole is used as a vulcanization accelerator, the content is 1 part by mass; the carbon black is used as a filler, the content is 50 parts by mass; and the antioxidant 264 is used as an antioxidant, the content is 3 parts by mass.

[0080] Comparative Example 2 and Example 1 are compared, and the difference lies in that the carboxyl content of the carboxyl nitrile rubber in Example 1 is 4 wt%; the carboxyl content of the carboxyl nitrile rubber in Comparative Example 2 is 0.5 wt%.

[0081] Comparative Example 3

[0082] The carboxyl nitrile rubber, the bisphenol A epoxy resin, the modified imidazole, the carbon black and the antioxidant 264 are mixed.

[0083] The content of the carboxyl nitrile raw rubber is 100 parts by mass; the carboxyl content of the carboxyl nitrile raw rubber is 0.5 wt%, and the acrylonitrile content is 70 wt%; the bisphenol A epoxy resin is used as a vulcanizing agent, the epoxy value of which is 435 g / eq, and the content is 6 parts by mass; the modified imidazole is used as a vulcanization accelerator, the content is 1 part by mass; the carbon black is used as a filler, the content is 50 parts by mass; and the anti-aging agent 264 is used as an antioxidant, the content is 3 parts by mass.

[0084] Comparative Example 3 is compared with Example 1, except that the carboxyl content of the carboxyl nitrile raw rubber in Example 1 is 4 wt%, and the acrylonitrile content is 35 wt%; the carboxyl content of the carboxyl nitrile raw rubber in Comparative Example 3 is 0.5 wt%, and the acrylonitrile content is 70 wt%.

[0085] Comparative Example 4

[0086] The carboxyl nitrile raw rubber, the bisphenol A epoxy resin, the modified imidazole, the carbon black and the anti-aging agent 264 are mixed.

[0087] The content of the carboxyl nitrile raw rubber is 100 parts by mass; the carboxyl content of the carboxyl nitrile raw rubber is 10 wt%, and the acrylonitrile content is 35 wt%; the bisphenol A epoxy resin is used as a vulcanizing agent, the epoxy value of which is 435 g / eq, and the content is 6 parts by mass; the modified imidazole is used as a vulcanization accelerator, the content is 1 part by mass; the carbon black is used as a filler, the content is 50 parts by mass; and the anti-aging agent 264 is used as an antioxidant, the content is 3 parts by mass.

[0088] Comparative Example 4 is compared with Example 1, except that the content of the carboxyl nitrile raw rubber in Example 1 is 100 parts by mass, and the carboxyl content is 4 wt%; the content of the carboxyl nitrile raw rubber in Comparative Example 4 is 35 parts by mass, and the carboxyl content is 10 wt%.

[0089] Comparative Example 5

[0090] The thermoplastic polyester elastomer (TPEE) composite diaphragm is used, and specifically, the composite diaphragm has a three-layer structure. The three-layer structure includes two surface layers and an intermediate layer, and the intermediate layer is located between the two surface layers. The two surface layers are both TPEE layers, and the thickness of each surface layer is 15 μm; and the intermediate layer is a polyacrylate pressure-sensitive adhesive film, and the thickness of the intermediate layer is 20 μm.

[0091] Comparative Example 6

[0092] The EPDM raw rubber, the dicumyl peroxide (DCP), the triallyl isocyanurate (TAIC), the white carbon black and the anti-aging agent 264 are mixed.

[0093] The content of EPDM raw rubber is 100 parts by mass; the content of white carbon black is 50 parts by mass, dicumyl peroxide (DCP) is used as a vulcanizing agent, and the content is 2 parts by mass; triallyl isocyanurate (TAIC) is used as a vulcanization accelerator, and the content is 1 part by mass; the content of aging agent 264 is 3 parts by mass.

[0094] The above-mentioned example 1, comparative example 1, comparative example 2, comparative example 3, comparative example 4, comparative example 6 are respectively vulcanized, the temperature is 200℃, the temperature is 10min, the pressure is 3MPa, and 0.1mm single-layer diaphragms are respectively prepared.

[0095] The example 1, comparative examples 1 to 6 of the present application are all based on the diaphragm with similar F0 as a reference.

[0096] The diaphragms obtained in example 1, comparative examples 1 to 6 are tested for oil absorption rate and product failure rate.

[0097] During the test, the diaphragm raw materials corresponding to example 1 and comparative examples 1 to 6 are cut into 5cm×5cm samples, and the mass is m. The samples are placed in a glass bottle containing rose essential oil, ensuring complete immersion, covered with a lid, and placed in an oven preheated to 65℃ for 96h. Then, after wiping the surface with a dust-free cloth, the weight is m1. The oil absorption rate is calculated according to the formula: oil absorption rate=(m1-m) / m×100%. The detailed test data of the oil absorption rate is shown in Table 3.

[0098] 100 sound generating devices are made from the diaphragms of example 1 and comparative examples 1 to 6. After adding rose essential oil to each sound generating device, they are placed in an oven at 65℃ for 96h. Then, after disassembling the product, the proportion of diaphragm deformation products is calculated, which is the product failure rate, and the calculation results are recorded in Table 3.

[0099] Meanwhile, 100 sound generating devices are made from the diaphragms of example 1 and comparative examples 1 to 6. Low-temperature reliability at-20℃ is performed, the power supply voltage is 0.8V, and the time is 196h. Then, after disassembling the product, the proportion of diaphragm breakage is calculated, which is the low-temperature breakage rate, and the calculation results are recorded in Table 3, and Figure 4 , which improves the intuitiveness.

[0100] Table 3. Test results of oil absorption rate and product failure rate of diaphragm

[0101]

[0102] In combination with Table 3 and Figure 4Comparing Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 5 and Comparative Example 6, the oil absorption rate of the diaphragm of Example 1 is 2% after 96 hours in a 65℃ environment, the oil absorption rate of the diaphragm of Comparative Example 1 is 21% under the same conditions, the oil absorption rate of the diaphragm of Comparative Example 2 is 21% under the same conditions, the oil absorption rate of the diaphragm of Comparative Example 5 is 10% under the same conditions, and the oil absorption rate of the diaphragm of Comparative Example 6 is 45% under the same conditions. It can be seen that the oil absorption rate of the diaphragm of Example 1 of the present application is significantly lower than that of Comparative Examples 1, 2, 5 and 6, has good oil resistance, strong product stability, and no adverse phenomena occur.

[0103] That is, in the carboxyl nitrile rubber of Example 1, the content of acrylonitrile is in the range of 20wt% to 40wt%, and the content of carboxyl is in the range of 3wt% to 6wt%. The content of acrylonitrile and the content of carboxyl of Comparative Example 1 are not in the range; the content of carboxyl of Comparative Example 2 is not in the range. Moreover, the diaphragm of Comparative Example 5 uses a thermoplastic polyester elastomer (TPEE) composite diaphragm, and the diaphragm of Comparative Example 6 uses EPDM rubber. It can be seen that whether the content of acrylonitrile and the content of carboxyl are not in the range of the present application, or the thermoplastic polyester elastomer (TPEE) composite diaphragm and EPDM rubber are used, there is a problem of poor oil resistance.

[0104] In addition, comparing Example 1, Comparative Example 3 and Comparative Example 4, although the oil absorption rate of the diaphragm of Comparative Example 3 and Comparative Example 4 is 1% after 96 hours in a 65℃ environment, the low-temperature membrane breaking rate of the diaphragm of Comparative Example 3 is 100%, and the low-temperature membrane breaking rate of the diaphragm of Comparative Example 4 is 95%. The low-temperature membrane breaking rate of the diaphragm of Example 1 is 0. Moreover, comparing Example 1 with Comparative Example 3 and Comparative Example 4, the content of acrylonitrile and the content of carboxyl of Comparative Example 3 are not in the above range, and the content of carboxyl of Comparative Example 4 is not in the above range. It can be seen that whether the content of acrylonitrile and the content of carboxyl are lower than the content range of the present application or higher than the content range of the present application, it is easy to cause the problem of low-temperature membrane breaking. That is, compared with Comparative Examples 3 and 4, the diaphragm of Example 1 of the present application has good low-temperature resistance and no low-temperature membrane breaking phenomenon occurs, while the diaphragms of Comparative Examples 3 and 4 are severely broken and cannot meet the reliability requirements.

[0105] In summary, the diaphragm according to the embodiment of the present application is prepared by mixing the carboxyl nitrile rubber film layer, the oil absorption rate of which is less than or equal to 5% after 96 hours in the environment of 65 DEG C, the content of acrylonitrile in the carboxyl nitrile rubber raw rubber is 20wt% to 40wt%, and the content of carboxyl is 3wt% to 6wt%. The carboxyl nitrile rubber raw rubber according to the embodiment of the present application contains a large amount of polar groups such as cyano (-C≡N) and carboxyl (-COOH), has good oil resistance, and the stability of acoustic performance is also improved.

[0106] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, but not for limiting the scope of the present application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A diaphragm, characterized in that: The diaphragm includes a mixed carboxyl nitrile rubber membrane layer, which is formed by mixing 100 parts by mass of carboxyl nitrile raw rubber, a vulcanizing agent, a filler, an antioxidant and other additives. The acrylonitrile content in the carboxyl nitrile raw rubber is 20wt% to 40wt%, the carboxyl content is 3wt% to 6wt%, and the oil absorption rate of the mixed carboxyl nitrile rubber membrane layer after 96 hours in a 65°C environment is ≤5%; the vulcanizing agent is at least one of amines, epoxies, metal oxides, metal peroxides, sulfur, and peroxides; and the content of the vulcanizing agent is 8 parts by mass to 20 parts by mass.

2. The diaphragm according to claim 1, wherein The other auxiliary agents include a vulcanization accelerator, which is at least one of tertiary ammonium, substituted urea, phenol, imidazole, acetylacetonate metal salt, boron trifluoride complex thiazole, sulfenamide, thiuram, thiourea, dithiocarbamate, aldehyde amine, arc, xanthate, and triallyl.

3. The diaphragm according to claim 2, characterized in that The content of the vulcanization accelerator is 0.1 parts by mass to 8 parts by mass.

4. The diaphragm according to claim 1, wherein 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.

5. The diaphragm according to claim 4, characterized in that The content of the antioxidant is 0.5 to 6 parts by mass.

6. The diaphragm according to claim 1, wherein: The filler is at least one of carbon black, white carbon black, talc, calcium carbonate, magnesium carbonate, dolomite, barium sulfate, zinc sulfide, aluminum powder, graphite, titanium dioxide, lithopone, phenolic resin, petroleum resin, and styrene resin.

7. The diaphragm according to claim 6, characterized in that The content of the filler is 5 parts by mass to 100 parts by mass.

8. The diaphragm according to claim 1, wherein: The other auxiliary agents include at least one of stearic acid, ultraviolet absorber, color paste and plasticizer.

9. The diaphragm according to any one of claims 1 to 8, characterized in that: The diaphragm is formed into a single-layer structure including only one layer of the mixed carboxyl nitrile rubber film layer; Alternatively, the diaphragm is formed into a composite layer structure, and the diaphragm includes at least one layer of the mixed carboxyl nitrile rubber membrane layer.

10. A sound-generating device, characterized in that: Comprising the diaphragm according to any one of claims 1 to 9.

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