Vibrating diaphragm for sound production device, sound production device and electronic equipment

Abstract

The invention discloses a vibrating diaphragm for a sound production device, the sound production device and electronic equipment. The vibrating diaphragm comprises a styrene-butadiene rubber layer, the styrene-butadiene rubber layer is prepared from a blending material, the blending material comprises a first styrene-butadiene copolymer and a second styrene-butadiene copolymer, the mass percentage of styrene in the first styrene-butadiene copolymer is 8%-12%, the mass percentage of styrene in the second styrene-butadiene copolymer is 40%-50%, and the mass percentage of styrene in the second styrene-butadiene copolymer is 10%-20%. The mass percentage of the first butylbenzene copolymer in the blended material is 50%-80%; the glass transition temperature of the styrene butadiene rubber layer is-40 DEG C to 0 DEG C. The blending material comprises the first styrene-butadiene copolymer with low glass transition temperature and the second styrene-butadiene copolymer with high glass transition temperature, so that the damping temperature range of the styrene-butadiene rubber layer can be effectively widened, and the vibrating diaphragm has a high loss factor in the temperature range of-60 DEG C to 20 DEG C.

Description

Technical Field

[0001] The present invention relates to the technical field of electroacoustic conversion, and more particularly to a diaphragm for a sound-generating device, a sound-generating device, and an electronic device. Background Art

[0002] In related technologies, the speaker diaphragm is made of paper, polypropylene, NBR, or metal alloys. These diaphragms are highly sensitive to temperature changes. At high temperatures (e.g., ≥60°C), the material modulus decreases significantly, resulting in a large F0 offset. At low temperatures (e.g., -60°C to 10°C), the material rigidity increases, the damping loss factor is less than 0.1, and the damping is low. This results in high THD distortion and poor listening performance within the operating temperature range. Furthermore, the diaphragm has a low elastic recovery rate, which causes residual deformation after vibration, affecting the accuracy and clarity of the sound. Furthermore, low-rebound materials undergo irreversible deformation under long-term, high-amplitude operation, causing the diaphragm to increase in size and deviate from its initial equilibrium position, impacting the sound quality. Summary of the Invention

[0003] An object of the present invention is to provide a new technical solution for a diaphragm of a sound-generating device.

[0004] According to a first aspect of the present invention, a diaphragm for a sound-generating device is provided. The diaphragm includes a styrene-butadiene rubber layer, the styrene-butadiene rubber layer being made from a blended material, the blended material including a first styrene-butadiene copolymer and a second styrene-butadiene copolymer, the first styrene-butadiene copolymer having a styrene content of 8%-12% by weight, the second styrene-butadiene copolymer having a styrene content of 40%-50% by weight, the first styrene-butadiene copolymer having a styrene content of 50%-80% by weight, and the second styrene-butadiene copolymer having a styrene content of 20%-50% by weight; the styrene-butadiene rubber layer having a glass transition temperature of -40°C to 0°C; the diaphragm having a ratio of F0 at 23°C to F0 at -20°C greater than or equal to 0.2 and less than 1; a dissipation factor of ≥0.15 within a temperature range of -60°C to 20°C; and an elastic recovery rate of ≥85% under a 10% tensile strain.

[0005] Optionally, the molecular structure of the first styrene-butadiene copolymer and / or the second styrene-butadiene copolymer is: , Among them, x, y, and z are natural numbers.

[0006] Optionally, the glass transition temperature of the first styrene-butadiene copolymer is from -60°C to -50°C, and the glass transition temperature of the second styrene-butadiene copolymer is from -20°C to 5°C.

[0007] Optionally, the blended material further includes a filler, which includes at least one of silica, carbon black, mineral whiskers, talc, diatomaceous earth, calcium carbonate, graphite, clay, and mica; the mass percentage of the filler in the blended material is 30%-60%.

[0008] Optionally, the blended material further includes a vulcanizing agent, which includes at least one of a sulfur system and a peroxide system, and the mass percentage of the vulcanizing agent in the blended material is 0.5%-3%.

[0009] Optionally, the vulcanizing agent includes a sulfur system, and the sulfur system includes at least one of sulfur, a sulfenic acid amine accelerator, a thiuram accelerator, zinc oxide, and stearic acid; And / or, the vulcanizing agent includes a peroxide system, and the peroxide system includes at least one of dicumyl peroxide, dibenzoyl peroxide, tert-butyl perbenzoate, dilauroyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and cumene hydroperoxide.

[0010] Optionally, the blended material further includes an accelerator, which includes at least one of tetramethylthiuram disulfide, tetraethylthiuram disulfide, 2-mercaptobenzothiazole, dibenzothiazole disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, zinc dimethyldithiocarbamate, diphenylguanidine, sulfenic acid amine accelerator, thiuram accelerator, zinc oxide, and stearic acid; the mass percentage of the accelerator in the blended material is 0.2%-2%.

[0011] Optionally, the blended material further includes an antioxidant, which includes at least one of N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-β-naphthylamine, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2,4-trimethyl-1,2-dihydroquinoline, 2-mercaptobenzimidazole, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; the mass percentage of the antioxidant in the blended material is 0.5%-4%.

[0012] Optionally, the diaphragm is formed into a single-layer structure, and the diaphragm is composed of a layer of the styrene-butadiene rubber layer; Alternatively, the diaphragm is formed into a multi-layer structure, the diaphragm includes at least one layer of the styrene-butadiene rubber layer and a composite layer, the composite layer is stacked with the styrene-butadiene rubber layer, and the composite layer is at least one of an elastomer layer, an engineering plastic layer and a film layer.

[0013] According to a second aspect of the present invention, a sound-generating device is provided, which includes the diaphragm of the present invention.

[0014] According to a third aspect of the present invention, an electronic device is provided, which includes the sound-generating device of the present invention.

[0015] In an embodiment of the present invention, the diaphragm includes a styrene-butadiene rubber layer, and the styrene-butadiene rubber layer is prepared from a blended material. The blended material includes a first styrene-butadiene copolymer with a low glass transition temperature and a second styrene-butadiene copolymer with a high glass transition temperature. The glass transition temperature of the styrene-butadiene rubber layer obtained after the cross-linking reaction is between -40°C and 0°C. In this way, the damping temperature range of the styrene-butadiene rubber layer can be effectively broadened, so that within the temperature range of -60°C to 20°C, the diaphragm has a high loss factor and good damping performance. When the mass percentage of the first styrene-butadiene copolymer in the blended material is 50%-80%, the diaphragm has high damping performance while the elastic recovery rate remains at a high level. The loss factor of the diaphragm within the temperature range of -60°C to 20°C is ≥0.15, and the elastic recovery rate of the diaphragm under 10% tensile strain is ≥85%. The sound-generating device using this diaphragm has low THD distortion and a higher listening yield. The ratio of F0 of the diaphragm 20 at 23° C. to F0 at −20° C. in the embodiment of the present invention is greater than or equal to 0.2 and less than 1, indicating that the diaphragm 20 has good vibration stability at different temperatures.

[0016] Further features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0018] Figure 1 is a cross-sectional view of a diaphragm according to an embodiment of the present invention.

[0019] Figure 2 is a perspective view of a sound-generating device according to an embodiment of the present invention.

[0020] Figure 3 is a cross-sectional view of a sound generating device according to an embodiment of the present invention.

[0021] Figure 4 is a cross-sectional view of a sound-generating device according to another embodiment of the present invention.

[0022] Figure 5 3 are total harmonic distortion (THD) curves of the sound-generating devices of the embodiment of the present invention and the comparative example.

[0023] Reference numerals: 100. Sound-generating device; 10. Housing; 20. Diaphragm; 30. Voice coil; 40. Permanent magnet. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0025] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0026] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered part of the specification.

[0027] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0028] It should be noted that like reference numerals and letters refer to like items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0029] The following describes in detail the diaphragm 20 for a sound-generating device according to an embodiment of the present invention with reference to the accompanying drawings.

[0030] According to one embodiment of the present invention, a diaphragm for a sound-generating device is provided. The diaphragm includes a styrene-butadiene rubber layer, the styrene-butadiene rubber layer being made from a blended material, the blended material including a first styrene-butadiene copolymer and a second styrene-butadiene copolymer, the first styrene-butadiene copolymer having a styrene content of 8%-12% by weight, the second styrene-butadiene copolymer having a styrene content of 40%-50% by weight, the first styrene-butadiene copolymer having a styrene content of 50%-80% by weight, and the second styrene-butadiene copolymer having a styrene content of 20%-50% by weight; the styrene-butadiene rubber layer having a glass transition temperature of -40°C to 0°C; the ratio of the F0 of the diaphragm at 23°C to the F0 at -20°C being greater than or equal to 0.2 and less than 1; the dissipation factor of the diaphragm within the temperature range of -60°C to 20°C being ≥0.15; and the elastic recovery rate of the diaphragm at a tensile strain of 10% being ≥85%.

[0031] Specifically, the diaphragm 20 is applied to a sound-generating device, which can be a large speaker or a micro speaker. The diaphragm 20 serves as a part of a vibration system. The diaphragm 20 is a ring-shaped diaphragm or a flat diaphragm. The diaphragm 20 includes a styrene-butadiene rubber layer. The diaphragm 20 is a single-layer structure or a multi-layer structure. The styrene-butadiene rubber layer is prepared using a blended material. The preparation method is, for example, compression molding, air pressure molding, etc. The blended material is mixed by a plurality of materials. For example, a plurality of materials are added to a mixer. Blending is performed in the mixer and the materials are evenly mixed to form a blended material.

[0032] Styrene-butadiene copolymer (SBR) is a copolymer made from styrene and butadiene through emulsion polymerization or solution polymerization. The main chain of the styrene-butadiene copolymer is a butadiene segment, which has high flexibility. The side chain of the styrene-butadiene copolymer contains styrene, which is a rigid group. Styrene can enhance the rigidity and heat resistance of the styrene-butadiene rubber layer. The higher the mass percentage of styrene in the styrene-butadiene copolymer, the higher the glass transition temperature of the styrene-butadiene copolymer; conversely, the lower the glass transition temperature. In an embodiment of the present invention, the mass percentage of styrene in the first styrene-butadiene copolymer is 8%-12%, and the mass percentage of styrene in the second styrene-butadiene copolymer is 40%-50%, so that the glass transition temperature of the first styrene-butadiene copolymer is lower and the glass transition temperature of the second styrene-butadiene copolymer is higher. That is to say, the blended material of the embodiment of the present invention includes a first styrene-butadiene copolymer with a low glass transition temperature and a second styrene-butadiene copolymer with a high glass transition temperature. The glass transition temperature of the styrene-butadiene rubber layer obtained after the cross-linking reaction is -40°C to 0°C. In this way, the damping temperature range of the styrene-butadiene rubber layer can be effectively broadened, so that the diaphragm has high damping performance within the temperature range of -60°C to 20°C, and the loss factor of the diaphragm within the temperature range of -60°C to 20°C is ≥0.15.

[0033] In addition, in an embodiment of the present invention, the mass percentage of the first styrene butadiene copolymer in the blend material is 50%-80%, and the mass percentage of the second styrene butadiene copolymer in the blend material is 20%-50%. The mass percentage of the first styrene butadiene copolymer in the blend material is related to the elastic recovery rate and loss factor of the diaphragm. When the mass percentage of the first styrene butadiene copolymer in the blend material is less than 50%, the elastic recovery rate of the diaphragm under 10% tensile strain is too low, for example, less than 85%, and the THD distortion of the sound-generating device using the diaphragm is high, and the listening yield is low. When the mass percentage of the first styrene butadiene copolymer in the blend material is greater than 80%, the loss factor of the diaphragm in the glass transition temperature range will be too low. When the mass percentage of the first styrene-butadiene copolymer in the blended material is 50%-80%, the diaphragm 20 exhibits high damping performance while maintaining a high elastic recovery rate. The diaphragm's loss factor within the temperature range of -60°C to 20°C is ≥ 0.15, and its elastic recovery rate at 10% tensile strain is ≥ 85%. Sound-generating devices employing this diaphragm exhibit low THD distortion and a higher listening yield.

[0034] In addition, the ratio of the F0 of the diaphragm 20 at 23°C to the F0 at -20°C is greater than or equal to 0.2 and less than 1. The F0 of the diaphragm 20 at 23°C represents the resonant frequency of the diaphragm 20 at room temperature. The F0 of the diaphragm 20 at -20°C represents the resonant frequency of the diaphragm 20 at -20°C. The closer the ratio of the F0 of the diaphragm 20 at 23°C to the F0 at -20°C is to 1, the better the vibration stability of the diaphragm 20 at different temperatures. The ratio of the F0 of the diaphragm 20 at 23°C to the F0 at -20°C of the embodiment of the present invention is greater than or equal to 0.2 and less than 1, indicating that the vibration stability of the diaphragm 20 at different temperatures is better.

[0035] Optionally, the ratio of F0 of the diaphragm 20 at 23° C. to F0 at −20° C. is 0.2, 0.22, 0.24, 0.26, 0.28, 0.3, 0.33, 0.35, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, etc. Those skilled in the art may select the ratio according to actual needs.

[0036] In an embodiment of the present invention, the diaphragm 20 includes a styrene-butadiene rubber layer, which is prepared from a blended material. The blended material includes a first styrene-butadiene copolymer with a low glass transition temperature and a second styrene-butadiene copolymer with a high glass transition temperature. The glass transition temperature of the styrene-butadiene rubber layer obtained after the cross-linking reaction is between -40°C and 0°C. In this way, the damping temperature range of the styrene-butadiene rubber layer can be effectively broadened, so that within the temperature range of -60°C to 20°C, the diaphragm 20 has a high loss factor and good damping performance. When the mass percentage of the first styrene-butadiene copolymer in the blended material is 50%-80%, the diaphragm has high damping performance while the elastic recovery rate remains at a high level. The loss factor of the diaphragm in the temperature range of -60°C to 20°C is ≥0.15, and the elastic recovery rate of the diaphragm under 10% tensile strain is ≥85%. The sound-generating device using this diaphragm has low THD distortion and a higher listening yield. The ratio of F0 of the diaphragm 20 at 23° C. to F0 at −20° C. in the embodiment of the present invention is greater than or equal to 0.2 and less than 1, indicating that the diaphragm 20 has good vibration stability at different temperatures.

[0037] In some specific embodiments of the present invention, the molecular structure of the first styrene-butadiene copolymer and / or the second styrene-butadiene copolymer is: , Among them, x, y, and z are natural numbers.

[0038] In this embodiment, the first styrene-butadiene copolymer and / or the second styrene-butadiene copolymer are of the above molecular formula. According to the mass percentage of styrene in the styrene-butadiene copolymer, the first styrene-butadiene copolymer and the second styrene-butadiene copolymer are selected appropriately.

[0039] In some specific embodiments of the present invention, the glass transition temperature of the first styrene-butadiene copolymer is -60°C to -50°C, and the glass transition temperature of the second styrene-butadiene copolymer is -20°C to 5°C.

[0040] In this embodiment, the glass transition temperature of the first styrene-butadiene copolymer is -60°C to -50°C, which can effectively broaden the low-temperature damping temperature range of the diaphragm. The glass transition temperature of the second styrene-butadiene copolymer is -20°C to 5°C, which can effectively broaden the high-temperature damping temperature range of the diaphragm. Ultimately, the glass transition temperature of the styrene-butadiene rubber layer is made to be -40°C to 0°C, and the diaphragm has a high loss factor and elastic recovery rate within the temperature range of -60°C to 20°C, and good vibration stability. The sound-generating device using the diaphragm has low THD distortion and a higher listening yield.

[0041] Optionally, the glass transition temperature of the first styrene butadiene copolymer is -60°C, -55°C, -50°C, etc., and the glass transition temperature of the second styrene butadiene copolymer is -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, etc. Those skilled in the art can set it according to actual needs.

[0042] In some specific embodiments of the present invention, the blended material further includes a filler, and the filler includes at least one of silica, carbon black, mineral whiskers, talc, diatomaceous earth, calcium carbonate, graphite, clay, and mica; the mass percentage of the filler in the blended material is 30%-60%.

[0043] In this embodiment, the filler is used to improve the mechanical properties of the diaphragm 20, such as tensile strength, hardness, etc. When preparing the diaphragm 20, the filler can be one or a mixture of multiple materials selected from the group consisting of silicon dioxide, carbon black, mineral whiskers, talc, diatomaceous earth, calcium carbonate, graphite, clay, and mica.

[0044] During compounding, the filler accounts for 30wt%-60wt% of the blended material.

[0045] It should be noted that the lower the filler content, the lower the tensile strength of the diaphragm 20, especially when the filler accounts for less than 30wt% by mass in the blended material, the reinforcing effect on the diaphragm 20 is poor. If the filler content is too high, for example, when the filler accounts for more than 60wt% by mass in the blended material, the elongation at break of the diaphragm 20 will decrease significantly, and the toughness of the material will be insufficient, causing the diaphragm 20 to easily break during vibration. When the filler accounts for 30wt%-60wt% by mass in the blended material, the diaphragm 20 has sufficient tensile strength, elongation at break, and toughness.

[0046] In some specific embodiments of the present invention, the blended material further includes a vulcanizing agent, which includes at least one of a sulfur system and a peroxide system, and the mass percentage of the vulcanizing agent in the blended material is 0.5%-3%.

[0047] In this embodiment, a vulcanizing agent is added to the blended material to cause the styrene-butadiene copolymer to undergo a cross-linking reaction, thereby forming a network structure.

[0048] It should be noted that, when batching, the mass of the vulcanizing agent accounts for 0.5wt%-3wt% of the total mass of the blended material. It should be noted that, the less the mass content of the vulcanizing agent, the less the cross-linking degree of the blended material, the loose network structure formed by the blended material, and the poor stability. When the mass proportion of the vulcanizing agent in the blended material is less than 0.5wt%, the cross-linking degree of the diaphragm 20 is insufficient, the network structure is poor in stability, the tensile strength and elastic modulus of the material are low, the temperature resistance deteriorates, the service life is short, and permanent deformation is likely to occur. When the mass proportion of the vulcanizing agent in the blended material is greater than 3wt%, the cross-linking degree of the material is too high and uneven, local rigidity areas will be formed, resulting in poor material homogeneity, tensile strength and tear strength will deteriorate, the glass transition temperature increases, and the elastic recovery rate is significantly reduced, and the product is very easy to break the film. When the mass content of the vulcanizing agent in the blended material is 0.5wt%-3wt%, it can not only ensure that the diaphragm 20 has an appropriate degree of cross-linking, but also enable the diaphragm 20 to maintain appropriate tensile strength, elastic modulus, tensile strength and tear strength, and the glass transition temperature, that is, the elastic recovery rate, is moderate, and the membrane rupture phenomenon is not easy to occur.

[0049] Optionally, the mass proportion of the vulcanizing agent in the blended material is 0.5wt%, 1wt%, 2wt%, 3wt%, etc. Further, the mass proportion of the vulcanizing agent in the blended material is 1wt%-2wt%. Those skilled in the art can make the selection according to actual needs.

[0050] Optionally, the vulcanizing agent includes a sulfur system, and the sulfur system includes at least one of sulfur, a sulfenic acid amine accelerator, a thiuram accelerator, zinc oxide, and stearic acid; And / or, the vulcanizing agent includes a peroxide system, and the peroxide system includes at least one of dicumyl peroxide, dibenzoyl peroxide, tert-butyl perbenzoate, dilauroyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and cumene hydroperoxide.

[0051] That is to say, when selecting the vulcanizing agent, one or more mixtures of sulfur, sulfenic acid amine accelerator, thiuram accelerator, zinc oxide, and stearic acid can be selected.

[0052] Alternatively, one or more mixtures of dicumyl peroxide, dibenzoyl peroxide, tert-butyl perbenzoate, dilauroyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and cumene hydroperoxide may be selected.

[0053] Alternatively, a mixture of sulfur, sulfenic acid amine accelerator, thiuram accelerator, zinc oxide, stearic acid, dicumyl peroxide, dibenzoyl peroxide, t-butyl perbenzoate, dilauroyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, and cumyl hydroperoxide may be selected.

[0054] The above-mentioned vulcanizing agents can all cause the styrene-butadiene copolymer to undergo a cross-linking reaction, thereby forming a network structure.

[0055] In some specific embodiments of the present invention, the blended material further includes an accelerator, which includes at least one of tetramethylthiuram disulfide, tetraethylthiuram disulfide, 2-mercaptobenzothiazole, dibenzothiazole disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, zinc dimethyldithiocarbamate, diphenylguanidine, sulfenic acid amine accelerator, thiuram accelerator, zinc oxide, and stearic acid; the mass percentage of the accelerator in the blended material is 0.2%-2%.

[0056] In this embodiment, the accelerator can accelerate the vulcanization speed, shorten the vulcanization time, and lower the vulcanization temperature, thereby reducing the amount of vulcanizing agent used. The blend material can include a mixture of one or more of tetramethylthiuram disulfide, tetraethylthiuram disulfide, 2-mercaptobenzothiazole, dibenzothiazole disulfide, N-cyclohexyl-2-benzothiazolesulfenamide, N-tert-butyl-2-benzothiazolesulfenamide, zinc dimethyldithiocarbamate, diphenylguanidine, sulfenamide accelerator, thiuram accelerator, zinc oxide, and stearic acid as the accelerator.

[0057] When mixing, the mass percentage of the accelerator in the blend material is 0.2%-2%. It should be noted that when the addition amount of the accelerator in the blend material is less than 0.2%, the accelerator accelerates the vulcanization speed, shortens the vulcanization time, and reduces the effect of the vulcanization temperature. When the addition amount of the accelerator in the blend material is greater than 2%, the speed of the vulcanization reaction is too fast, which easily leads to an uneven network structure of the internal molecules of the rubber, and the diaphragm 20 is prone to breakage. When the mass percentage of the accelerator in the blend material is 0.2%-2%, the vulcanization reaction speed of the blend material is moderate.

[0058] Optionally, the mass percentage of the accelerator in the blended material is 0.2%, 1%, 1.5%, 2%, etc., which can be set by those skilled in the art according to actual needs.

[0059] In some specific embodiments of the present invention, the blended material further includes an antioxidant, which includes at least one of N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-β-naphthylamine, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2,4-trimethyl-1,2-dihydroquinoline, 2-mercaptobenzimidazole, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; the mass percentage of the antioxidant in the blended material is 0.5%-4%.

[0060] During the use of polymer materials, over time, molecular chains break and autocatalytically active free radicals are generated. These autocatalytically active free radicals can accelerate the aging of the polymer material itself. Adding an antioxidant to the diaphragm 20 can halt the generation of autocatalytically active free radicals in the blended material, thereby delaying the aging of the blended material and extending the service life of the diaphragm 20. When preparing the diaphragm 20, one or more of a mixture of N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-β-naphthylamine, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2,4-trimethyl-1,2-dihydroquinoline, 2-mercaptobenzimidazole, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline can be selected as the antioxidant. The above antioxidants are all miscible with the styrene-butadiene copolymer, thereby preventing the diaphragm 20 from aging and extending the service life of the diaphragm 20.

[0061] During the mixing process, the antioxidant accounts for 0.5wt%-4wt% of the blended material.

[0062] It should be noted that, in the blended material, if the amount of antioxidant added is too little, for example, when the mass proportion of the antioxidant in the blended material is less than 0.5wt%, it is impossible to prevent the diaphragm 20 from aging and extend the service life of the diaphragm 20. If the amount of antioxidant added is too much, for example, when the mass proportion of the antioxidant in the blended material is greater than 4wt%, the antioxidant cannot be well soluble in the styrene-butadiene copolymer, so that the antioxidant cannot be evenly dispersed in the blended material, resulting in a decrease in the mechanical properties of the diaphragm 20. However, when the mass proportion of the antioxidant in the blended material is 0.5wt%-4wt%, the antioxidant can effectively extend the service life of the diaphragm 20, and the antioxidant can be evenly dispersed in the blended material, and the prepared diaphragm 20 can maintain good mechanical properties.

[0063] Alternatively, the mass proportion of antioxidant in the blend material is 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt% etc. Further, the mass proportion of antioxidant in the blend material is 2wt%-3wt%. Of course, the mass proportion of antioxidant in the blend material is not limited to the above embodiment, and those skilled in the art can select according to actual needs.

[0064] In some specific embodiments of the present invention, the diaphragm 20 is formed into a single-layer structure, and the diaphragm 20 is composed of a layer of the styrene-butadiene rubber layer; Alternatively, the diaphragm 20 is formed into a multi-layer structure, and the diaphragm 20 includes at least one layer of the styrene-butadiene rubber layer and a composite layer, the composite layer and the styrene-butadiene rubber layer are stacked, and the composite layer is at least one of an elastomer layer, an engineering plastic layer and a film layer.

[0065] That is to say, the diaphragm 20 of the embodiment of the present invention can be a single-layer styrene-butadiene rubber layer. The diaphragm 20 has a simple structure and a simple manufacturing process.

[0066] Alternatively, the diaphragm 20 may have a multi-layer structure. Specifically, at least one styrene-butadiene rubber layer is laminated with a composite layer to form the multi-layer diaphragm 20. The composite layer is at least one of an elastomer layer, an engineering plastic layer, and a film layer. The multi-layer structure may have 2, 3, 4, 5, 6, 7, or other layers.

[0067] Optionally, the elastomer layer includes one or more of thermoplastic polyurethane elastomer, thermoplastic polyester elastomer, thermoplastic polyamide elastomer, and thermoplastic polystyrene elastomer. The engineering plastic layer includes one or more of PEEK, PAR, PMI, PET, PEN, PA, PEI, and LCP. The film layer includes a silicone film and / or an acrylic film. The composite layer may be one or more layers.

[0068] According to another embodiment of the present invention, a sound generating device is provided. Figure 2-Figure 4 As shown, the sound-generating device 100 includes the diaphragm 20 of the above embodiment.

[0069] like Figure 2-Figure 3 As shown, the sound-generating device 100 is a micro-speaker. The sound-generating device 100 may include a housing 10, a magnetic circuit system, and a vibration system. The magnetic circuit system includes a permanent magnet 40, which is used to form a magnetic gap. The vibration system includes a diaphragm 20 and a voice coil 30. The diaphragm 20 and the permanent magnet 40 are both connected to the housing 10. The permanent magnet 40 is disposed on one side of the diaphragm 20 along the thickness direction. One end of the voice coil 30 is connected to the diaphragm 20, and the other end is located in the magnetic gap.

[0070] In this example, the diaphragm 20 may be a surround diaphragm. The surround diaphragm comprises a central portion, a surround portion, and a fixed portion, connected in sequence from the inside out. The fixed portion is used to connect to the housing 10. A dome is provided on the central portion, and the voice coil 30 is connected to the central portion or the dome.

[0071] Figure 4 Another sound-generating device 100 according to an embodiment of the present invention is shown. The sound-generating device is a large loudspeaker.

[0072] The sound-generating device 100 may include a shell 10, a magnetic circuit system and a vibration system. The magnetic circuit system includes a permanent magnet 40 and a U iron 90. The permanent magnet 40 and the U iron 90 are used to form a magnetic gap. The vibration system includes a diaphragm 20, a cone 50, a skeleton 80, a voice coil 30 and a dust cover 60. The inner edge of the cone 50 is connected to one end of the skeleton 80. The dust cover 60 is provided on one end of the skeleton 80. The voice coil 30 is arranged around the other end of the skeleton 80. The diaphragm 20 is connected to the outer edge of the cone 50. The diaphragm 20 and the permanent magnet 40 are both connected to the shell 10. The permanent magnet 40 is provided on one side of the diaphragm 20 along the thickness direction. One end of the voice coil 30 is located in the magnetic gap. The shell 10 is provided with a spring 70. The spring 70 is connected to the middle part of the skeleton 80.

[0073] In this example, the diaphragm 20 may be a surround diaphragm. The surround diaphragm includes a central portion, a surround portion, and a fixed portion connected from the inside out. The fixed portion is used to connect to the housing 10. The central portion is connected to the outer edge of the cone 50.

[0074] In other examples, the diaphragm 20 may also be a planar diaphragm or other structures. Those skilled in the art may determine this according to actual conditions, and no specific limitation is made here.

[0075] In other examples, the diaphragm 20 may also be a planar diaphragm or other structures. Those skilled in the art may determine this according to actual conditions, and no specific limitation is made here.

[0076] According to yet another embodiment of the present invention, an electronic device is provided.

[0077] The electronic device is, for example, a mobile phone, a computer, a television, a speaker, an intercom, a VR device, an AR device, smart glasses, etc. The electronic device includes the sound-generating device 100 described in the above embodiment. Of course, the electronic device of the present invention also includes at least all the beneficial effects of the above embodiment, which will not be described in detail here.

[0078] The diaphragm 20 and the sound generating device 100 of the present invention are described in detail below with reference to specific embodiments. It should be noted that the following description is merely exemplary and does not specifically limit the present invention.

[0079] (1) Glass transition temperature, loss factor and elastic recovery rate of styrene-butadiene rubber layers with different component contents Diaphragm specimens were prepared with varying weight percentages of the first and second styrene-butadiene copolymers in the blend. Their glass transition temperature, loss factor over a temperature range of -60°C to 20°C, and elastic recovery at 10% tensile strain were tested. The diaphragm specimens were 100 μm thick and compression molded.

[0080] The glass transition temperature was tested using a differential scanning calorimeter according to the test standard: GB / T19466.1-2004, with a starting temperature of -100°C, an ending temperature of 100°C, and a temperature rate of 20°C / min.

[0081] Dissipation factor was measured using a dynamic mechanical analyzer (DMA) according to ASTM D5026-23. Test conditions: tensile mode, temperature: -60°C to 100°C, heating rate: 3°C / min, strain: 0.2%, frequency: 1 Hz. The dissipation factor of the diaphragm specimens at different temperatures was measured, and the maximum and minimum values ​​were used as the endpoints of the loss factor range.

[0082] Elastic recovery at 10% tensile strain was tested according to ASTM D5026-23. Test conditions: tensile mode, temperature: 23°C, strain: 10%, holding time: 5 minutes, relaxation time: 10 minutes, recovery time: 5 minutes.

[0083] The contents of the components in the blended materials and the test results are shown in Table 1.

[0084] Table 1 - Test results of blend material components and diaphragm samples

[0085] As shown in Table 1, as the mass percentage of the first styrene-butadiene copolymer in the blend decreases and the mass percentage of the second styrene-butadiene copolymer increases, the glass transition temperature of the diaphragm gradually increases, the overall loss factor in the temperature range of -60°C to 20°C gradually increases, and the elastic recovery rate under 10% tensile strain gradually decreases. This is primarily due to the higher mass percentage of styrene in the second styrene-butadiene copolymer compared to the first styrene-butadiene copolymer. The higher the mass percentage of styrene in the styrene-butadiene copolymer, the higher the glass transition temperature and loss factor of the styrene-butadiene copolymer; conversely, the lower the mass percentage. As the mass percentage of the second styrene-butadiene copolymer in the blend increases, the mass percentage of styrene in the styrene-butadiene rubber layer gradually increases, resulting in a gradual increase in the glass transition temperature and loss factor of the diaphragm.

[0086] (2) Performance comparison between the examples and the comparative examples Example: The diaphragm 20 is a single-layer ring-shaped diaphragm. The thickness of the diaphragm 20 is 110 μm. The diaphragm 20 includes a styrene-butadiene rubber layer. The styrene-butadiene rubber layer is molded from a blended material, wherein the blended material includes a first styrene-butadiene copolymer and a second styrene-butadiene copolymer. The first styrene-butadiene copolymer has a styrene content of 10% by mass and a glass transition temperature of -52°C. The second styrene-butadiene copolymer has a styrene content of 45% by mass and a glass transition temperature of -3°C. The specific ingredients of the blended material are shown in Table 2.

[0087] Comparative Example: Diaphragm 20 is a single-layer surround diaphragm. Diaphragm 20 has a thickness of 110 μm and is molded from styrene-butadiene rubber (SBR). SBR has a glass transition temperature of -42°C. See Table 2 for the specific material composition.

[0088] Table 2 - Ingredients of Example and Comparative Example Diaphragm 20

[0089] Performance testing: (1) The hardness (Shore A), glass transition temperature, loss factor (-60°C to 10°C, taking the minimum value), and elastic recovery rate under 10% tensile strain of the diaphragm 20 of the embodiment and the comparative example were tested respectively. It should be noted that, considering the difference between the size of the diaphragm 20 and the sample size required by the corresponding test standard, a sample composed of the same material as the diaphragm 20 was selected for the relevant tests to characterize the characteristics of the diaphragm 20. Since the sample and the diaphragm 20 were composed of the same material, the relevant characteristics of the sample measured were consistent with the relevant characteristics of the diaphragm 20.

[0090] The hardness (Shore A) and elastic recovery rate under 10% tensile strain were tested according to ASTM-D882 standard at a test temperature of 23°C.

[0091] The test methods for loss factor and glass transition temperature are as described above.

[0092] (2) Assemble the diaphragms 20 of the embodiment and the comparative example into the sound-generating device. The two diaphragms 20 have the same size. Test the THD curves of the two sound-generating devices. Figure 5 .

[0093] Results and Analysis: (1) The test results of the hardness (Shore A), glass transition temperature, loss factor (-60°C to 10°C, taking the minimum value), and elastic recovery rate under 10% tensile strain of the diaphragm 20 of the embodiment and the comparative example are shown in Table 3.

[0094] Table 3 - Performance test of the embodiment and comparative example diaphragm 20

[0095] As shown in Table 3, the hardness of the diaphragm 20 of the embodiment of the present invention is the same as that of the diaphragm 20 of the comparative example. The glass transition temperature of the diaphragm 20 of the embodiment of the present invention is higher than that of the diaphragm 20 of the comparative example. This is because the blended material of the diaphragm of the embodiment includes a first styrene-butadiene copolymer with a low glass transition temperature and a second styrene-butadiene copolymer with a high glass transition temperature. The second styrene-butadiene copolymer with a high glass transition temperature can extend the glass transition temperature of the diaphragm to a higher temperature range, resulting in a higher glass transition temperature of the diaphragm 20 of the embodiment than that of the diaphragm 20 of the comparative example.

[0096] The loss factor and elastic recovery rate under 10% tensile strain of the diaphragm 20 of the embodiment of the present invention are both higher than the loss factor and elastic recovery rate under 10% tensile strain of the diaphragm 20 of the comparative example. This is mainly because the blended material of the embodiment of the present invention includes a first styrene butadiene copolymer with a low glass transition temperature and a second styrene butadiene copolymer with a high glass transition temperature. The glass transition temperature of the styrene butadiene rubber layer obtained after the cross-linking reaction is -25°C, which effectively broadens the damping temperature range of the styrene butadiene rubber layer, so that the embodiment diaphragm has a high loss factor within the temperature range of -60°C to 20°C. When the mass percentage of the first styrene butadiene copolymer in the blended material is 60%, the embodiment diaphragm has both high elastic recovery rate and loss factor.

[0097] (2) By Figure 5 It can be seen that in the range of 100Hz-600Hz, the THD curve of the sound-emitting device of the embodiment of the present invention is below the THD curve of the sound-emitting device of the comparative example. In the range above 600Hz, the THD curve of the sound-emitting device of the embodiment of the present invention is slightly different from the THD curve of the sound-emitting device of the comparative example. This is mainly because the blended material of the embodiment of the present invention includes a first styrene-butadiene copolymer with a low glass transition temperature and a second styrene-butadiene copolymer with a high glass transition temperature. The glass transition temperature of the styrene-butadiene rubber layer obtained after the cross-linking reaction is -25°C, which effectively broadens the damping temperature range of the styrene-butadiene rubber layer, so that the diaphragm of the embodiment has a high loss factor in the temperature range of -60°C to 20°C. When the mass percentage of the first styrene-butadiene copolymer in the blended material is 60%, the diaphragm of the embodiment has both high elastic recovery rate and loss factor, which can effectively reduce the THD of the sound-emitting device using the diaphragm 20 and has a higher listening yield.

[0098] The above embodiments focus on the differences between the various embodiments. As long as the different optimization features between the various embodiments are not contradictory, they can be combined to form a better embodiment. Considering the simplicity of the text, they will not be repeated here.

[0099] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that modifications may be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A diaphragm for a sound-generating device, characterized in that: The diaphragm includes a styrene-butadiene rubber layer, which is prepared from a blended material. The blended material includes a first styrene-butadiene copolymer and a second styrene-butadiene copolymer. The mass percentage of styrene in the first styrene-butadiene copolymer is 8%-12%, the mass percentage of styrene in the second styrene-butadiene copolymer is 40%-50%, the mass percentage of the first styrene-butadiene copolymer in the blended material is 50%-80%, and the mass percentage of the second styrene-butadiene copolymer in the blended material is 20%-50%; the glass transition temperature of the styrene-butadiene rubber layer is -40°C to 0°C; the ratio of the F0 of the diaphragm at 23°C to the F0 at -20°C is greater than or equal to 0.2 and less than 1, the loss factor of the diaphragm in the temperature range of -60°C to 20°C is ≥0.15, and the elastic recovery rate of the diaphragm under 10% tensile strain is ≥85%.

2. The diaphragm according to claim 1, wherein The molecular structure of the first styrene-butadiene copolymer and / or the second styrene-butadiene copolymer is: ， Among them, x, y, and z are natural numbers.

3. The diaphragm according to claim 1, wherein The glass transition temperature of the first styrene-butadiene copolymer is from -60°C to -50°C, and the glass transition temperature of the second styrene-butadiene copolymer is from -20°C to 5°C.

4. The diaphragm according to claim 1, wherein The blended material further includes a filler, which includes at least one of silicon dioxide, carbon black, mineral whiskers, talc, diatomaceous earth, calcium carbonate, graphite, clay, and mica; the mass percentage of the filler in the blended material is 30%-60%.

5. The diaphragm according to claim 1, wherein: The blended material further includes a vulcanizing agent, which includes at least one of a sulfur system and a peroxide system. The mass percentage of the vulcanizing agent in the blended material is 0.5%-3%.

6. The diaphragm according to claim 5, characterized in that The vulcanizing agent includes a sulfur system, and the sulfur system includes at least one of sulfur, sulfenic acid amine accelerator, thiuram accelerator, zinc oxide, and stearic acid; And / or, the vulcanizing agent includes a peroxide system, and the peroxide system includes at least one of dicumyl peroxide, dibenzoyl peroxide, tert-butyl perbenzoate, dilauroyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and cumene hydroperoxide.

7. The diaphragm according to claim 1, wherein: The blended material also includes an accelerator, which includes at least one of tetramethylthiuram disulfide, tetraethylthiuram disulfide, 2-mercaptobenzothiazole, dibenzothiazole disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, zinc dimethyldithiocarbamate, diphenylguanidine, sulfenic acid amine accelerator, thiuram accelerator, zinc oxide, and stearic acid; the mass percentage of the accelerator in the blended material is 0.2%-2%.

8. The diaphragm according to claim 1, wherein: The blended material also includes an antioxidant, which includes at least one of N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-β-naphthylamine, 2,6-di-tert-butyl-p-cresol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2,4-trimethyl-1,2-dihydroquinoline, 2-mercaptobenzimidazole, and 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline; the mass percentage of the antioxidant in the blended material is 0.5%-4%.

9. The diaphragm according to claim 1, wherein: The diaphragm is formed into a single-layer structure, and the diaphragm is composed of a layer of the styrene-butadiene rubber layer; Alternatively, the diaphragm is formed into a multi-layer structure, the diaphragm includes at least one layer of the styrene-butadiene rubber layer and a composite layer, the composite layer is stacked with the styrene-butadiene rubber layer, and the composite layer is at least one of an elastomer layer, an engineering plastic layer and a film layer.

10. A sound-generating device, characterized in that: Comprising a diaphragm as described in any one of claims 1-9.

11. An electronic device, characterized in that: Comprising the sound-generating device as claimed in claim 10.

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