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 is of a single-layer structure, the vibrating diaphragm is prepared by carrying out compression molding on a blending material, the blending material comprises ethylene-acrylate rubber and acrylate rubber, the hardness of the vibrating diaphragm is 45A-80A, and the room temperature damping factor of the vibrating diaphragm is greater than or equal to 0.25. The vibrating diaphragm is prepared from a blending material containing ethylene-acrylate rubber and acrylate rubber through mould pressing, and a single-layer structure is formed. The mode of compression molding enables the processing of the vibrating diaphragm to be simple. In addition, due to hydrogen bonds formed by ester groups in the vibrating diaphragm and microscopic phase separation of materials, the damping performance of the vibrating diaphragm is improved. In addition, under the large amplitude of the vibrating diaphragm, polarization and distortion are remarkably reduced, and the phenomenon of diaphragm breakage is not prone to occurring.

Description

Technical Field

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

[0002] In the related art, the diaphragm of high-performance micro speakers is usually made of AEM rubber material. As consumers' demands for the sound quality and volume of speakers of electronic devices become higher and higher, the amplitude of the speaker diaphragm becomes larger and larger. The increase in amplitude makes the polarization and distortion of the speaker higher and higher during vibration, which puts higher requirements on the damping performance of the diaphragm. However, the room temperature damping factor of the diaphragm made of AEM rubber material is low, the amplitude symmetry is poor, the distortion is large, it is difficult to meet the use requirements of the speaker, and the processing precision of the diaphragm is low and the process is complicated. 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 is formed into a single-layer structure, the diaphragm is prepared by compression molding of a blended material, the blended material includes ethylene-acrylate rubber and acrylate rubber, the hardness of the diaphragm is 45A-80A, and the room temperature damping factor of the diaphragm is greater than or equal to 0.25.

[0005] Optionally, the elongation at break of the diaphragm at room temperature is greater than or equal to 110%; And / or, the retention rate of the elongation at break of the diaphragm after aging for 168 hours at a temperature of 150° C. is greater than or equal to 50%.

[0006] Optionally, the stress loss rate of the diaphragm is greater than or equal to 30%; And / or, the glass transition point of the diaphragm is -60°C-10°C.

[0007] Optionally, the ethylene-acrylate rubber is a ternary structure, and its molecular formula is: , Wherein, x, y, z are natural numbers; R and R' are alkyl groups; The blended material further comprises an amine cross-linking agent, and the amine cross-linking agent comprises at least one of hexamethylenediamine, hexamethylenediamine salt, hexamethylenediamine carbamate, triethylenetetramine, 2,2'-methylenedianiline and di-o-tolylguanidine. Optionally, the mass proportion of the amine cross-linking agent in the blended material is 0.2%-5wt%.

[0008] Optionally, the ethylene-acrylate rubber is a binary structure, and its molecular formula is:

[0009] Wherein, x and y are natural numbers; R is an alkyl group; The blended material also includes a peroxide crosslinking agent, which includes at least one of 1,3-1,4-di(tert-butylperoxyisopropyl)benzene, diisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, 4,4'-bis(tert-butylperoxy)valerate, 1,1'-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane and 2,4-dichlorobenzoyl peroxide.

[0010] Optionally, the mass proportion of the peroxide crosslinking agent in the blended material is 0.2wt%-5wt%.

[0011] Optionally, in the blended material, the ratio of the mass of the acrylic rubber to the total mass of the acrylic rubber and the ethylene-acrylate rubber is 5%-95%.

[0012] Optionally, the blended material further includes a reinforcing agent, which is at least one of white carbon black, talcum powder, carbon black, and calcium carbonate, and the mass proportion of the reinforcing agent in the blended material is 5wt%-60wt%.

[0013] Optionally, the blended material also includes an antioxidant, which includes at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD, and antioxidant WH-02, and the mass proportion of the antioxidant in the blended material is 0.2wt%-6wt%.

[0014] Optionally, the room temperature storage modulus of the diaphragm is 2MPa-50Mpa; And / or, the density of the diaphragm is 1.1 g / cm 3 -1.65g / cm 3 ; And / or, the thickness of the diaphragm is 20 μm-150 μm.

[0015] According to a second aspect of the present invention, a sound-generating device is provided, which includes the diaphragm described in the present invention.

[0016] According to a third aspect of the present invention, an electronic device is provided, which includes the sound generating device of the present invention.

[0017] The diaphragm 20 of the embodiment of the present invention is prepared by molding a blended material including ethylene-acrylate rubber and acrylate rubber. The molding method allows the diaphragm 20 to have high processing precision and simple processing technology. The hydrogen bonds formed by the ester groups in the diaphragm 20 and the microscopic phase separation of the material improve the damping performance of the diaphragm 20. The room temperature damping factor of the diaphragm 20 of the embodiment of the present invention is greater than or equal to 0.25, and the hardness is 45A-80A, which makes the diaphragm 20 significantly reduce polarization and distortion at a larger amplitude, and is not prone to membrane breakage. The diaphragm of the present invention is a single-layer structure with good mechanical properties. It can meet the use requirements without being compounded with other material layers. The structural design is simple and the production cost is low.

[0018] 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 attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0020] Figure 1 is a cross-sectional view of a diaphragm according to an embodiment of the present invention.

[0021] Figure 2 is a stereoscopic diagram of a sound-generating device according to an embodiment of the present invention.

[0022] Figure 3 is a cross-sectional view of a sound generating device according to an embodiment of the present invention.

[0023] Figure 4 3 is a curve showing the displacement of the four corners and the geometric center of the diaphragm as a function of frequency according to an embodiment of the present invention.

[0024] Figure 5 This is a curve showing how the displacements of the four corners and the geometric center of the diaphragm of Example 1 vary with frequency.

[0025] Figure 6 This is a curve showing how the displacements of the four corners and the geometric center of the diaphragm of Example 2 vary with frequency.

[0026] Reference numerals: 100. Sound-generating device; 10. Shell; 20. Diaphragm; 30. Voice coil; 40. Permanent magnet. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that 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 unless otherwise specifically stated.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0032] The diaphragm 20 according to the embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0033] According to a specific embodiment of the present invention, a diaphragm 20 for a sound-generating device is provided. Figure 1 As shown, the diaphragm is formed into a single-layer structure, and the diaphragm is prepared by molding a blended material, the blended material includes ethylene-acrylate rubber and acrylate rubber, the hardness of the diaphragm is 45A-80A, and the room temperature damping factor of the diaphragm is greater than or equal to 0.25.

[0034] In other words, the diaphragm 20 is applied to a sound-generating device. The diaphragm 20 serves as a part of a vibration system. The diaphragm 20 is a folded ring diaphragm or a flat diaphragm. The diaphragm 20 is a single-layer structure and does not need to be compounded with other membrane layers. This makes the preparation process of the diaphragm 20 simple. The diaphragm 20 is prepared from a blended material. The preparation method is, for example, compression molding. The blended material is a mixture of multiple materials, for example, multiple materials are added to a mixer. Blending is performed in a mixer and mixed evenly to form a blended material. In this embodiment, the blended material includes AEM rubber and ACM rubber. Among them, AEM rubber is an elastomer obtained by copolymerization with ethylene-acrylate as the main monomer. ACM rubber is an elastomer obtained by copolymerization with acrylate as the main monomer.

[0035] During the preparation, the AEM rubber and the ACM rubber are added to a mixer for mixing to form a blended material. The blended material is formed into a single-layer diaphragm 20 by compression molding. The blended material is vulcanized during molding. Of course, the method for preparing the diaphragm 20 is not limited to the above embodiment, and those skilled in the art can select according to actual needs.

[0036] The mold for compression molding usually includes a male mold and a female mold. A cavity for compression molding is formed between the male mold and the female mold. During compression molding, first, the blended material is prepared into a blank, which is a film, a block, etc. Then, the blank is placed on the male mold or the female mold. Next, the male mold and the female mold are molded together, heated, and a set pressure is applied so that the blank fills the cavity to form the shape of the diaphragm 20. The blank is vulcanized and formed during the heating process, and finally the diaphragm 20 is formed. Finally, the formed diaphragm is demolded from the mold. Of course, it is also possible to preheat the male mold and / or the female mold first, and then place the blank on the male mold or the female mold. Preheating is conducive to the flow of the blank, so that the blank can quickly fill the cavity when the mold is closed, thereby improving the efficiency of compression molding. In addition, preheating can speed up the vulcanization speed of the blank, so that the diaphragm 20 can be quickly solidified and formed. Compression molding makes the processing accuracy of the diaphragm 20 high and the processing technology simple.

[0037] In an embodiment of the present invention, the diaphragm 20 is made of a blended material. The blended material includes ethylene-acrylate rubber and acrylate rubber. Due to the hydrogen bonds formed by the ester groups in the diaphragm 20 and the microscopic phase separation of the material, the damping performance of the diaphragm 20 is improved, for example, the room temperature damping factor is greater than or equal to 0.25. Compared with the diaphragm made of pure AEM rubber, under the same hardness conditions, the room temperature damping factor of the diaphragm 20 of the embodiment of the present invention is significantly improved, for example, an increase of more than 20%. When the hardness of the diaphragm 20 of the present invention is greater than or equal to 45A, the room temperature damping factor of the diaphragm 20 is greater than or equal to 0.25. When the hardness of the diaphragm 20 is less than or equal to 80A, the diaphragm 20 can maintain sufficient toughness and is not prone to membrane rupture. Therefore, the room temperature damping factor of the diaphragm 20 of the embodiment of the present invention is greater than or equal to 0.25, and the hardness is 45A-80A, which makes the diaphragm 20 significantly reduce polarization and distortion at a larger amplitude, and is not prone to membrane rupture. The single-layer diaphragm in the present invention has good mechanical properties and can meet the use requirements without being compounded with other material layers. It has a simple structural design, is easy to manufacture, and saves costs.

[0038] Optionally, the hardness of the diaphragm 20 is 45A, 50A, 60A, 70A, 80A, etc. The room temperature damping factor is 0.25, 0.3, 0.34, 0.4, 0.45, etc. Of course, the hardness and room temperature damping factor of the diaphragm 20 are not limited to the above embodiments, and those skilled in the art can select according to actual needs.

[0039] The diaphragm 20 of the embodiment of the present invention is prepared by molding a blended material including ethylene-acrylate rubber and acrylate rubber. The molding method makes the processing of the diaphragm 20 simple. Moreover, the hydrogen bonds formed by the ester groups in the diaphragm 20 and the microscopic phase separation of the material improve the damping performance of the diaphragm 20. The room temperature damping factor of the diaphragm 20 of the embodiment of the present invention is greater than or equal to 0.25, and the hardness is 45A-80A, which makes the polarization and distortion of the diaphragm 20 significantly reduced at a larger amplitude, and the membrane breakage phenomenon is not easy to occur. The diaphragm of the present invention is a single-layer structure with good mechanical properties. It can meet the use requirements without being compounded with other material layers. The structural design is simple and the production cost is low.

[0040] In a specific embodiment of the present invention, the elongation at break of the diaphragm at room temperature is greater than or equal to 110%; And / or, the retention rate of the elongation at break of the diaphragm after aging for 168 hours at a temperature of 150° C. is greater than or equal to 50%.

[0041] In this embodiment, the elongation at break of the diaphragm 20 is tested at room temperature. The elongation at break of the diaphragm 20 can be tested according to the ASTM D412-2016 standard. The elongation at break refers to the percentage of the length of the material when it breaks after being stretched to the length before stretching. The lower the elongation at break of a material, the worse the toughness of the material, and the more likely it is that the membrane will break. The diaphragm 20 of the embodiment of the present invention has an elongation at break greater than or equal to 110% due to the large polarity and intermolecular force of ACM rubber. The diaphragm 20 has good toughness and is not prone to membrane breakage.

[0042] The elongation at break retention rate refers to the degree of retention of the elongation at break of a material after aging relative to the initial elongation at break. Before the test, the diaphragm 20 was aged for 168 hours at 150°C. The elongation at break of the diaphragm 20 can be tested in accordance with the ASTM D412-2016 standard. It should be noted that the higher the elongation at break retention rate, the higher the temperature resistance and stability of the material; conversely, the lower the temperature resistance and stability of the material. In the diaphragm 20 of the embodiment of the present invention, since the ACM rubber of the blended material contains a large number of ester groups, a large number of hydrogen bonds are formed between molecules. A large number of hydrogen bonds make the intermolecular force large, so the elongation at break retention rate of the diaphragm 20 is significantly improved. The elongation at break retention rate of the diaphragm 20 after aging for 168 hours at 150°C is greater than or equal to 50%, so that the diaphragm 20 has high temperature resistance and high stability under long-term use, which meets its use requirements under extreme working conditions.

[0043] Optionally, the elongation at break of the diaphragm 20 after aging for 168 hours at 150° C. is 110%, 200%, 300%, etc. The elongation at break retention rate is 50%, 53%, 55%, 58%, 60%, 65%, etc. Of course, the elongation at break and the elongation at break retention rate are not limited to the above embodiments, and those skilled in the art can set them according to actual needs.

[0044] In a specific embodiment of the present invention, the stress loss rate of the diaphragm 20 is greater than or equal to 30%; And / or, the glass transition point of the diaphragm is -60°C-10°C.

[0045] In an embodiment of the present invention, the diaphragm 20 satisfies at least one of the above conditions or satisfies two conditions at the same time. The stress loss rate refers to the ratio of the stress reduction of the material due to factors such as time, environment, and temperature during the stress process. The stress loss rate of the diaphragm 20 can be tested according to the ASTM D5026-15 standard. It should be noted that the higher the stress loss rate, the more complete the stress release of the diaphragm 20 during the molding process, and the lower the dimensional deformation of the diaphragm 20 when it is placed; conversely, the more incomplete the stress release of the diaphragm 20 during the preparation process, and the higher the dimensional deformation of the diaphragm 20 when it is placed. The diaphragm 20 of the embodiment of the present invention is prepared by adopting the above-mentioned blended material, so that the stress loss rate of the diaphragm 20 is greater than or equal to 30%. This shows that the stress of the diaphragm 20 is completely released during the molding process, and the dimensional deformation of the diaphragm 20 is low when it is placed. Of course, the stress loss rate is not limited to the above embodiment, and those skilled in the art can set it according to actual needs.

[0046] The glass transition point (i.e., glass transition temperature, Tg) refers to the temperature at which a material changes from a glassy state to a highly elastic state. The glass transition point can be tested according to the ASTM D882 standard. In this embodiment, the glass transition point of the diaphragm 20 is -60°C-10°C, so that the diaphragm 20 can be used for a long time in a low temperature environment without the diaphragm 20 being broken due to vibration stretching.

[0047] Optionally, the stress loss rate is 30%, 33%, 35%, 38%, 40%, 45%, 50%, etc. The glass transition point of the diaphragm 20 is -60°C, -50°C, -40°C, -30°C, -20°C, -10°C, 0°C, 10°C, etc. Of course, the stress loss rate and glass transition point of the diaphragm 20 are not limited to the above embodiments, and those skilled in the art can select according to actual needs.

[0048] In a specific embodiment of the present invention, the ethylene-acrylate rubber is a ternary structure, and its molecular formula is: , Wherein, x, y, z are natural numbers; R and R' are alkyl groups; The blended material further comprises an amine cross-linking agent, and the amine cross-linking agent comprises at least one of hexamethylenediamine, hexamethylenediamine salt, hexamethylenediamine carbamate, triethylenetetramine, 2,2'-methylenedianiline and di-o-tolylguanidine. In an embodiment of the present invention, R and R' are alkyl groups. Optionally, R' is methyl, ethyl or butyl, and the AEM rubber containing the above groups is widely available, and the preparation process of the diaphragm 20 is simple. The amine crosslinking agent is a compound containing an amino functional group, which can undergo a crosslinking reaction with ACM rubber and AEM rubber to form a crosslinked structure, thereby curing the blended material and improving the mechanical properties, heat resistance and chemical resistance of the blended material. Optionally, the amine crosslinking agent may include any one or a mixture of hexamethylenediamine, hexamethylenediamine salt, hexamethylenediamine carbamate, triethylenetetramine, 2,2'-methylenedianiline and di-o-tolylguanidine. Those skilled in the art can choose according to actual needs. During preparation, after the AEM rubber and the ACM rubber are evenly mixed, an amine crosslinking agent is added. The ternary structure of ethylene-acrylate and acrylate containing carboxylic acid groups and / or epoxy groups can undergo a crosslinking reaction with the amine crosslinking agent to cure and form, and finally form the diaphragm 20.

[0049] In a specific embodiment of the present invention, the mass percentage of the amine cross-linking agent in the blended material is 0.2wt%-5wt%.

[0050] In an embodiment of the present invention, when mixing, the mass of the amine cross-linking agent accounts for 0.2wt%-5wt% of the total mass of the blended material. It should be noted that the less the mass content of the amine cross-linking agent, the insufficient degree of cross-linking of the blended material, and the poor stability of the macromolecular network structure formed by the blended material. When the mass proportion of the amine cross-linking agent in the blended material is less than 0.2wt%, the degree of cross-linking of the diaphragm 20 is insufficient, and the stability of the macromolecular network structure is poor. If the mass content of the amine cross-linking agent is too high, the elongation at break of the diaphragm 20 is too low. Especially when the mass proportion of the amine cross-linking agent in the blended material is greater than 5wt%, the elongation at break of the diaphragm 20 is too low, and film breakage is prone to occur. When the mass content of the amine cross-linking agent in the blended material is 0.2wt%-5wt%, it can not only ensure that the diaphragm 20 has a suitable degree of cross-linking, but also make the diaphragm 20 have a higher elongation at break.

[0051] Optionally, the mass proportion of the amine crosslinking agent in the blended material is 0.2wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc. Further, the mass proportion of the amine crosslinking agent in the blended material is 0.5wt%-3wt%. Of course, the mass proportion of the amine crosslinking agent in the blended material is not limited to the above embodiments, and those skilled in the art can make a selection according to actual needs.

[0052] In a specific embodiment of the present invention, the ethylene-acrylate rubber is a binary structure, and its molecular formula is:

[0053] Wherein, x and y are natural numbers; R is an alkyl group; The blended material also includes a peroxide crosslinking agent, which includes at least one of 1,3-1,4-di(tert-butylperoxyisopropyl)benzene, diisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, 4,4'-bis(tert-butylperoxy)valerate, 1,1'-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane and 2,4-dichlorobenzoyl peroxide.

[0054] In the embodiment of the present invention, the binary structure of ethylene-acrylate rubber and acrylate rubber are reacted with a peroxide crosslinking agent to prepare the diaphragm 20 by compression molding. The peroxide crosslinking agent can generate free radicals on the main chain of the dimer, and the free radicals form crosslinking points, which polymerize the dimers together through the crosslinking points to form a macromolecular network structure.

[0055] Optionally, the peroxide crosslinking agent includes 1,3-1,4-di(tert-butylperoxyisopropyl)benzene, diisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylperoxide isopropylbenzene, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, 4,4'-bis(tert-butylperoxy)valerate n-butyl ester, 1,1'-bis(tert-butylperoxy)-3,3,5 trimethylcyclohexane and 2,4-dichlorobenzoyl peroxide, one or more mixtures. The above peroxide crosslinking agents can all generate free radicals on the main chain of the dimer to form a macromolecular network structure by crosslinking. During preparation, after the AEM rubber and the ACM rubber are evenly mixed, the peroxide crosslinking agent is added. The blended material formed by the binary structure of AEM rubber, ACM rubber and peroxide cross-linking agent is compression molded in a mold to form the diaphragm 20.

[0056] In a specific embodiment of the present invention, the mass percentage of the peroxide crosslinking agent in the blended material is 0.2wt%-5wt%.

[0057] In an embodiment of the present invention, when mixing, the mass of the peroxide crosslinking agent accounts for 0.2wt%-5wt% of the total mass of the blended material. It should be noted that the less the mass content of the peroxide crosslinking agent, the insufficient degree of crosslinking of the blended material, and the poor stability of the macromolecular network structure formed by the blended material. When the mass proportion of the peroxide crosslinking agent in the blended material is less than 0.2wt%, the degree of crosslinking of the diaphragm 20 is insufficient, and the stability of the macromolecular network structure is poor. If the mass content of the peroxide crosslinking agent is too high, the elongation at break of the diaphragm 20 is too low. In particular, when the mass proportion of the peroxide crosslinking agent in the blended material is greater than 5wt%, the elongation at break of the diaphragm 20 is too low, and film breakage is prone to occur. When the mass content of the peroxide crosslinking agent in the blended material is 0.2wt%-5wt%, it can not only ensure that the diaphragm 20 has a sufficient degree of crosslinking, but also make the diaphragm 20 have a higher elongation at break.

[0058] Optionally, the mass proportion of the peroxide crosslinking agent in the blended material is 0.2wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, etc. Of course, the mass proportion of the peroxide crosslinking agent in the blended material is not limited to the above embodiments, and those skilled in the art can make a selection according to actual needs.

[0059] In a specific embodiment of the present invention, in the blended material, the ratio of the mass of the acrylic rubber to the total mass of the acrylic rubber and the ethylene-acrylate rubber is 5%-95%.

[0060] It should be noted that, since the ester content in ACM rubber is much higher than that in AEM rubber, there is a certain microscopic phase separation in the diaphragm 20, which significantly increases the damping performance of the diaphragm 20 during movement. Therefore, as the ACM rubber content increases, the ester content in the blended material increases significantly, the hydrogen bond content between the molecular chains increases, the friction force increases during the movement of the molecular chains, the internal friction increases, and the damping performance of the diaphragm 20 increases significantly. However, due to the poor molecular flexibility of ACM rubber, when there are too many hydrogen bonds, the toughness of the diaphragm 20 will decrease. In this embodiment, when the ratio of the mass of the acrylic rubber to the total mass of the acrylic rubber and the ethylene-acrylic rubber is 5%-95%, the diaphragm 20 has both high damping performance and toughness.

[0061] Optionally, in the blended material, the ratio of the mass of the acrylic rubber to the total mass of the acrylic rubber and the ethylene-acrylic rubber is 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%. Further, in the blended material, the ratio of the mass of the acrylic rubber to the total mass of the acrylic rubber and the ethylene-acrylic rubber is 7%-75%. Of course, the ratio of the mass of the acrylic rubber to the total mass of the acrylic rubber and the ethylene-acrylic rubber is not limited to the above embodiments, and those skilled in the art can make a selection according to actual needs.

[0062] In a specific embodiment of the present invention, the blended material further includes a reinforcing agent, which is at least one of white carbon black, talcum powder, carbon black, and calcium carbonate, and the mass proportion of the reinforcing agent in the blended material is 5wt%-60wt%.

[0063] In this embodiment, the reinforcing agent is used to improve the mechanical properties of the diaphragm 20, such as tensile strength, hardness, etc. When preparing the diaphragm 20, the reinforcing agent can be one or a mixture of white carbon black, talcum powder, carbon black, and calcium carbonate. Those skilled in the art can select according to actual needs.

[0064] It should be noted that the lower the content of the reinforcing agent, the lower the tensile strength of the diaphragm 20, especially when the mass proportion of the reinforcing agent in the blended material is less than 5wt%, the reinforcing effect on the diaphragm 20 is poor. If the content of the reinforcing agent is too high, for example, when the mass proportion of the reinforcing agent in the blended material is greater than 60wt%, the elongation at break of the diaphragm 20 will decrease significantly, and the toughness of the material is insufficient, resulting in the diaphragm 20 being prone to membrane breakage during vibration. When the mass proportion of the reinforcing agent in the blended material is 5wt%-60wt%, the diaphragm 20 has sufficient tensile strength, elongation at break and toughness.

[0065] Optionally, the mass proportion of the reinforcing agent in the blended material is 5wt%, 10wt%, 20wt%, 30wt%, 40wt%, 50wt%, 60wt%, etc. Of course, the mass proportion of the reinforcing agent in the blended material is not limited to the above embodiments, and those skilled in the art can make a selection according to actual needs.

[0066] In a specific embodiment of the present invention, the blended material also includes an antioxidant, and the antioxidant includes at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD, and antioxidant WH-02, and the mass proportion of the antioxidant in the blended material is 0.2wt%-6wt%.

[0067] During the use of polymer materials, as time goes by, the molecular chain breaks and produces autocatalytic active free radicals. Autocatalytic active free radicals can accelerate the aging of the polymer materials themselves. Adding an antioxidant to the diaphragm 20 can stop the generation of autocatalytic 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 mixtures of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD, and antioxidant WH-02 can be selected as antioxidants. The above antioxidants are all miscible with AEM rubber and ACM rubber, thereby preventing the diaphragm 20 from aging and extending the service life of the diaphragm 20.

[0068] It should be noted that in the blended material, the amount of antioxidant added is too small, for example, when the mass proportion of the antioxidant in the blended material is less than 0.2wt%, it is impossible to prevent the aging of the diaphragm 20 and extend the service life of the diaphragm 20. Too much antioxidant is added, for example, when the mass proportion of the antioxidant in the blended material is greater than 6wt%, the antioxidant cannot be well soluble with AEM rubber and ACM rubber, so that the antioxidant cannot be evenly dispersed in the blended material, resulting in a decrease in the mechanical properties of the diaphragm 20. When the mass proportion of the antioxidant in the blended material is 0.2wt%-6wt%, 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.

[0069] Optionally, the weight percentage of the antioxidant in the blended material is 0.2wt%, 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, etc. Further, the weight percentage of the antioxidant in the blended material is 0.5wt%-2wt%. Of course, the weight percentage of the antioxidant in the blended material is not limited to the above embodiments, and those skilled in the art can select according to actual needs.

[0070] In a specific embodiment of the present invention, the room temperature storage modulus of the diaphragm 20 is 2MPa-50Mpa; And / or, the density of the diaphragm 20 is 1.1 g / cm 3 -1.65g / cm 3 ; And / or, the thickness of the diaphragm 20 is 20 μm-150 μm.

[0071] In the embodiment of the present invention, the diaphragm 20 satisfies any one, two or all three of the above conditions.

[0072] In specific implementation, the room temperature storage modulus of the diaphragm 20 of the embodiment of the present invention is 2MPa-50Mpa. The storage modulus is used to characterize the ability of a material to resist elastic deformation. The room temperature storage modulus refers to the amount of energy stored when a material is subjected to an external force under room temperature conditions. The room temperature storage modulus can be tested in accordance with the ASTM D882 standard. It should be noted that when the room temperature storage modulus of the diaphragm 20 is too small, for example, less than 2MPa, the strength of the diaphragm 20 is too small, and polarization is prone to occur. When the room temperature storage modulus of the diaphragm 20 is too large, for example, greater than 50MPa, the hardness of the diaphragm 20 is too high, the elongation at break is low, and membrane rupture is prone to occur. When the room temperature storage modulus of the diaphragm 20 is 2MPa-50Mpa, the diaphragm 20 can have both good elasticity and hardness, and membrane rupture is not prone to occur.

[0073] The room temperature storage modulus of the diaphragm 20 in the embodiment of the present invention is 2MPa, 10MPa, 20MPa, 30MPa, 40MPa, 50MPa, etc. Of course, the room temperature storage modulus of the diaphragm 20 is not limited to the above embodiment, and those skilled in the art can set it according to actual needs.

[0074] The density of the diaphragm 20 in the embodiment of the present invention is 1.1 g / cm 3 -1.65g / cm 3 It should be noted that when the density of the diaphragm 20 is too high, for example, greater than 1.65 g / cm 3 When the density of the diaphragm 20 is too small, for example, less than 1.1 g / cm 3 When the density of the diaphragm 20 is 1.1 g / cm 3 -1.65g / cm 3 At the same time, the diaphragm 20 has moderate quality, good mid-frequency performance, and the processing technology of the diaphragm 20 is simple.

[0075] Optionally, the density of the diaphragm 20 is 1.1 g / cm 3 , 1.2g / cm 3 , 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.65g / cm 3 Of course, the density of the diaphragm 20 is not limited to the above embodiment, and those skilled in the art can set it according to actual needs.

[0076] The thickness of the diaphragm 20 of the embodiment of the present invention is 20μm-150μm. The diaphragm 20 is a single-layer structure. It should be noted that when the thickness of the diaphragm 20 is too low, for example, less than 20μm, the diaphragm 20 is easily deformed during processing, which is not conducive to the processing and molding of the diaphragm 20. When the thickness of the diaphragm 20 is too high, for example, greater than 150μm, the vibration space of the diaphragm 20 is affected, and the diaphragm 20 is easily rubbed against the shell. When the thickness of the diaphragm 20 is 20μm-150μm, it can not only ensure the convenience of processing of the diaphragm 20, but also save the vibration space of the diaphragm 20.

[0077] Optionally, the thickness of the diaphragm 20 is 20 μm, 40 μm, 50 μm, 80 μm, 100 μm, 120 μm, 150 μm, etc. Of course, the thickness of the diaphragm 20 is not limited to the above embodiment, and those skilled in the art can set it according to actual needs.

[0078] According to another embodiment of the present invention, a sound generating device is provided. Figure 2-Figure 3 As shown, the sound-generating device 100 includes the diaphragm 20 of the above embodiment.

[0079] In this example, the sound-generating device 100 may be a sound-generating device such as a speaker unit or a speaker assembly, and those skilled in the art may determine it according to actual conditions, and no specific limitation is made here.

[0080] like Figure 2-Figure 3 As shown, the sound-generating device 100 may include a housing 10, a magnetic circuit system and a vibration system, wherein the magnetic circuit system includes a permanent magnet 40, and the permanent magnet 40 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 arranged 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.

[0081] In this example, the diaphragm 20 may be a folded ring diaphragm. The folded ring diaphragm includes a central portion, a folded ring portion, and a fixed portion connected in sequence from the inside to the outside. The fixed portion is used to connect to the housing 10. The central portion is provided with a dome, and the voice coil 30 is connected to the central portion or the dome.

[0082] In other examples, the diaphragm 20 may also be a planar diaphragm or other structures, which can be determined by those skilled in the art according to actual conditions and is not specifically limited here.

[0083] According to yet another embodiment of the present invention, an electronic device is provided.

[0084] 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 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 repeated here.

[0085] The diaphragm 20 and the sound generating device 100 of the present invention are described in detail below in conjunction with specific embodiments. It should be noted that the following description is only exemplary and does not specifically limit the present invention.

[0086] (I) Room temperature damping factor and elongation at break of the diaphragm 20 of the embodiment of the present invention at different ACM rubber mass contents The thickness of the diaphragm is 85 μm, and the diaphragm 20 is made of a blend of AEM rubber and ACM rubber, wherein the mass content of ACM rubber is the percentage of the mass of ACM rubber to the total mass of ACM rubber and AEM rubber. The mass contents of ACM rubber are 5wt%, 7wt%, 40wt%, 75wt% and 95wt% respectively. The room temperature damping factor of the diaphragm 20 is measured. Among them, the test standard for the room temperature damping factor of the diaphragm 20 is the ASTM D5026-23 standard. The test standard for the elongation at break of the diaphragm 20 is the ASTMD412-2016 standard. The measured data are shown in Table 1. 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 with the same composition material as the diaphragm 20 is selected for relevant tests to characterize the characteristics of the diaphragm 20. Since the sample is made of the same composition material as the diaphragm 20 itself, the relevant characteristics of the measured sample are consistent with the relevant characteristics of the diaphragm 20.

[0087] Table 1 - Room temperature damping factor and elongation at break of diaphragms

[0088] As can be seen from Table 1, the blended material includes ethylene-acrylate rubber and acrylate rubber, and the room temperature damping factor of the obtained diaphragm is greater than 0.25. This is mainly because the content of ester groups in ACM rubber is much higher than that in AEM rubber, and because the blended material includes ACM rubber and AEM rubber, the hydrogen bonds formed by the ester groups in the diaphragm 20 and the microscopic phase separation of the material improve the damping performance of the diaphragm 20. As the content of ACM rubber increases, the content of ester groups in the diaphragm 20 increases significantly, the content of hydrogen bonds between molecular chains increases significantly, the friction force increases during the movement of the molecular chains, the internal friction increases, and the damping performance of the diaphragm 20 increases significantly. When the content of ACM rubber is too high, the content of AEM rubber will be too low, resulting in a decrease in the content of hydrogen bonds between molecular chains. Therefore, as can be seen from Table 1, as the content of ACM rubber increases, the room temperature damping factor of the diaphragm 20 first increases and then decreases. In addition, since the molecular flexibility of ACM rubber is relatively poor, as the number of hydrogen bonds increases, the toughness of the diaphragm 20 decreases, thereby reducing the elongation at break of the diaphragm 20 and making it easy for the membrane to break.

[0089] (II) Elongation at break and tensile strength of diaphragm 20 at different silica mass contents The thickness of the diaphragm 20 is 85 μm. The diaphragm 20 is made of a blend of AEM rubber and ACM rubber, wherein the mass content of ACM rubber (the ratio of the mass of ACM rubber to the total mass of ACM rubber and AEM rubber) is 35%. The mass contents of white carbon black in the blend are 5wt%, 37wt% and 60wt% respectively. Among them, the test standard for the elongation at break and tensile strength of the diaphragm 20 is the ASTM D412-2016 standard. The measured elongation at break and tensile strength of different diaphragms 20 are shown in Table 2. 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 with the same composition material as the diaphragm 20 is selected for relevant tests to characterize the characteristics of the diaphragm 20. Since the sample is made of the same composition material as the diaphragm 20 itself, the relevant characteristics of the measured sample are consistent with the relevant characteristics of the diaphragm 20.

[0090] Table 2 - Elongation at break and tensile strength of diaphragm

[0091] As can be seen from Table 2, as the mass content of white carbon black increases, the elongation at break of the diaphragm 20 gradually decreases, and the tensile strength of the diaphragm 20 gradually increases. When the mass content of white carbon black is greater than 60wt%, it cannot meet the actual use requirements, and the elongation at break of the diaphragm 20 is too low, which also cannot meet the use requirements. When the mass content of white carbon black is less than 5wt%, the tensile strength of the diaphragm 20 is too low. This is because the main component of white carbon black is silicon dioxide. White carbon black is a white amorphous powder, and its surface contains relatively active hydroxyl groups. Due to the strong interaction between the surface of white carbon black and the interface of ACM rubber and AEM rubber, when the material is subjected to force, the molecular chain is easier to slide on the surface of white carbon black, but it is not easy to detach from it. In this way, the molecular chain and white carbon black form a strong bond that can slide, which increases the tensile strength of the diaphragm 20. However, the reinforcing agent, as a filler, occupies the space of the diaphragm 20, reducing the stretching space of the molecular chain. Therefore, as the mass content of white carbon black increases, the elongation at break of the diaphragm 20 gradually decreases.

[0092] (III) Changes in displacement of the diaphragm 20 of the sound-generating device of the embodiment of the present invention and the sound-generating device of the comparative example with frequency The sound-generating device of the embodiment of the present invention is a miniature sound-generating device. The miniature sound-generating device adopts the diaphragm of the embodiment of the present invention, wherein the diaphragm is a folded ring diaphragm. The folded ring diaphragm includes a central portion, a folded ring portion arranged around the central portion, and an edge portion arranged around the folded ring portion. A reinforcement layer is provided at the central portion. The edge portion is connected to the shell. The thickness of the diaphragm is 90 μm, and the diaphragm is made of a blended material consisting of AEM rubber and ACM rubber. Among them, the AEM rubber adopts a binary structure. Tert-butyl peroxide is used as a cross-linking agent. The diaphragm 20 is molded. The diaphragm 20 is rectangular as a whole. The ratio of the mass of ACM rubber to the total mass of ACM rubber and AEM rubber is 45%, the glass transition point of the diaphragm 20 is -35.1°C, and the density is 1.44 g / cm 3 , the room temperature storage modulus is 12.5 MPa, and the room temperature damping factor is 0.4017. The F0 of the sound generating device is 721 Hz. The displacements of the four corners and the geometric center of the diaphragm 20 are measured.

[0093] The diaphragm used in the sound-generating device of comparative example 1 is made of AEM rubber. The AEM rubber adopts a binary structure. Tert-butyl isopropylbenzene peroxide is used as a cross-linking agent. The diaphragm is a single-layer structure with a thickness of 90 μm and a density of 1.42 g / cm 3 , the glass transition point is -35.7℃, the room temperature storage modulus is 12.6MPa, and the room temperature damping factor is 0.1934. The F0 of the sound-generating device is 721Hz.

[0094] The diaphragm used in the sound-generating device of comparative example 2 is made of ACM rubber. Tertiary butyl isopropylbenzene peroxide is used as a cross-linking agent. The diaphragm is a single-layer structure with a thickness of 90 μm and a density of 1.43 g / cm 3 , the glass transition point is -34.1℃, the room temperature storage modulus is 12.4MPa, and the room temperature damping factor is 0.2232. The F0 of the sound-generating device is 720Hz.

[0095] The structures and dimensions of the sound-generating devices of Comparative Examples 1 and 2 are the same as those of the sound-generating devices of the embodiment of the present invention. The outer dimensions of the diaphragms of Comparative Examples 1 and 2 are the same as those of the diaphragm 20 of the embodiment of the present invention. The displacements of the four corners and the geometric center of the diaphragm 20 of Comparative Examples 1 and 2 are measured.

[0096] According to the above content, the density, glass transition temperature, and room temperature storage modulus of the diaphragm 20 of the embodiment of the present invention are close to those of the diaphragms of Comparative Examples 1 and 2, but the room temperature damping factor of the diaphragm 20 of the embodiment of the present invention is significantly higher than that of the diaphragms of Comparative Examples 1 and 2. The F0 of the micro-sound-generating device of the embodiment of the present invention is close to the F0 of the micro-sound-generating device of Comparative Examples 1 and 2, that is, the low-frequency loudness of the three is close. The displacement curves of the four corners and the geometric center of the diaphragm 20 of the embodiment of the present invention, Comparative Examples 1 and 2 as a inverse of the frequency are shown in FIG. Figures 4 to 6 As shown. Figure 4-Figure 6 It can be seen that the symmetry of the amplitude of the diaphragm 20 of the embodiment of the present invention is better than that of the diaphragm 20 of Comparative Examples 1 and 2, and the displacements of the four corners and the displacement of the geometric center of the diaphragm 20 of the embodiment of the present invention are basically the same, and no polarization phenomenon occurs. However, there is a large difference in the displacements of the four corners and the displacements of the geometric center of the diaphragms of Comparative Examples 1 and 2, which indicates that the diaphragms of Comparative Examples 1 and 2 have polarization phenomena.

[0097] In summary, in the diaphragm 20 of the embodiment of the present invention, the ratio of the mass of ACM rubber to the total mass of ACM rubber and AEM rubber is 45%. Since the blended material includes AEM rubber and ACM rubber, the damping performance of the diaphragm 20 is improved due to the hydrogen bonds formed by the ester groups and the microscopic phase separation of the material. The room temperature damping factor of the diaphragm 20 reaches 0.4017, which is much higher than the room temperature damping factor of the diaphragms of Comparative Examples 1 and 2, thereby effectively suppressing the polarization and distortion of the diaphragm 20. The glass transition point of the diaphragm 20 of the embodiment of the present invention is -35.1°C, so that the diaphragm 20 can be used for a long time in a low temperature environment without the membrane rupture caused by vibration stretching of the diaphragm 20. The room temperature storage modulus of the diaphragm 20 of the embodiment of the present invention is 12.5MPa, so that the diaphragm 20 can have good elasticity. The sound-emitting device prepared by the diaphragm 20 of the embodiment of the present invention has small polarization and distortion.

[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 example, it will be appreciated 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 will be appreciated by those skilled in the art that the above embodiments may be modified 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 is formed into a single-layer structure, and the diaphragm is prepared by molding a blended material, the blended material includes ethylene-acrylate rubber and acrylate rubber, the hardness of the diaphragm is 45A-80A, and the room temperature damping factor of the diaphragm is greater than or equal to 0.

25.

2. The diaphragm according to claim 1, characterized in that: The elongation at break of the diaphragm at room temperature is greater than or equal to 110%; And / or, the retention rate of the elongation at break of the diaphragm after aging for 168 hours at a temperature of 150° C. is greater than or equal to 50%.

3. The diaphragm according to claim 1, characterized in that: The stress loss rate of the diaphragm is greater than or equal to 30%; And / or, the glass transition point of the diaphragm is -60°C-10°C.

4. The diaphragm according to claim 1, characterized in that: The ethylene-acrylate rubber is a ternary structure, and its molecular formula is: ， Wherein, x, y, z are natural numbers; R and R' are alkyl groups; The blended material further comprises an amine cross-linking agent, and the amine cross-linking agent comprises at least one of hexamethylenediamine, hexamethylenediamine salt, hexamethylenediamine carbamate, triethylenetetramine, 2,2'-methylenedianiline and di-o-tolylguanidine.

5. The diaphragm according to claim 4, characterized in that: The mass proportion of the amine cross-linking agent in the blended material is 0.2%-5wt%.

6. The diaphragm according to claim 1, characterized in that: The ethylene-acrylate rubber is a binary structure, and its molecular formula is: Wherein, x and y are natural numbers; R is an alkyl group; The blended material also includes a peroxide crosslinking agent, which includes at least one of 1,3-1,4-di(tert-butylperoxyisopropyl)benzene, diisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)-3-hexyne, 4,4'-bis(tert-butylperoxy)valerate, 1,1'-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane and 2,4-dichlorobenzoyl peroxide.

7. The diaphragm according to claim 6, characterized in that: The mass proportion of the peroxide crosslinking agent in the blended material is 0.2wt%-5wt%.

8. The diaphragm according to claim 1, characterized in that: In the blended material, the ratio of the mass of the acrylic rubber to the total mass of the acrylic rubber and the ethylene-acrylate rubber is 5%-95%.

9. The diaphragm according to claim 1, characterized in that: The blended material also includes a reinforcing agent, which is at least one of white carbon black, talcum powder, carbon black, and calcium carbonate. The weight proportion of the reinforcing agent in the blended material is 5wt%-60wt%.

10. The diaphragm according to claim 1, characterized in that: The blended material also includes an antioxidant, which includes at least one of antioxidant N-445, antioxidant 246, antioxidant 4010, antioxidant SP, antioxidant RD, antioxidant ODA, antioxidant OD, and antioxidant WH-02, and the weight proportion of the antioxidant in the blended material is 0.2wt%-6wt%.

11. The diaphragm according to claim 1, characterized in that: The room temperature storage modulus of the diaphragm is 2MPa-50Mpa; And / or, the density of the diaphragm is 1.1 g / cm 3 -1.65g / cm 3 ; And / or, the thickness of the diaphragm is 20 μm-150 μm.

12. A sound-generating device, characterized in that: Comprising a diaphragm as described in any one of claims 1-11.

13. An electronic device, characterized in that: Comprising the sound-generating device as claimed in claim 12.

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