Rubber diaphragm, sound production device and use thereof

Abstract

In the present invention, a rubber diaphragm comprises 1%-40% by mass of a distortion ameliorating agent. The distortion ameliorating agent is a high-molecular polymer with a main chain having a -Si-O- structure and comprises a side group and / or a side chain, the number-average molecular weight of the side chain of the distortion ameliorating agent being 60-20,000, and the end group and the side group of the distortion ameliorating agent respectively comprising at least one of methyl, ethyl, propyl, butyl, phenyl, naphthyl, hydroxyl, amino, an ester group and amido, wherein at least one of the end group, the side group and the side chain of the distortion ameliorating agent has 0.03%-30% by mass of a special chemical crosslinking point. The distortion ameliorating agent can be widely used in rubber diaphragms, since same does not sacrifice the physical performance advantages of the main rubber, can also significantly ameliorate the distortion performance of the rubber diaphragm, and can also improve the demolding performance of the rubber diaphragm. The present invention further provides a sound production device and the use thereof.

Description

A rubber sound membrane, a sound-generating device and its application

Technical field

[0001] The present invention relates to the field of new materials, and in particular to a rubber sound membrane, a sound-generating device and applications thereof. [Background Technology]

[0002] Rubber diaphragms, due to their unique physical properties, have gained popularity in high-end sound-generating devices. As demand for sound quality increases, so too do the requirements for acoustic components, particularly for high-temperature resistance and waterproofing. Silicone rubber and fluorosilicone rubber, with their excellent high-temperature resistance and waterproofing properties, have attracted widespread attention from acoustic researchers. However, silicone rubber and fluorosilicone rubber suffer from poor damping. Direct application of these materials to speaker diaphragms inevitably results in significant distortion, severely limiting their application in the diaphragm sector.

[0003] Many researchers have conducted extensive research on the poor damping properties of silicone rubber and fluorosilicone rubber. First, attempts to improve rubber damping by adding fillers or small molecule damping agents have limited effectiveness or poor heat resistance. Second, attempts to improve damping by combining other rubbers have limited effectiveness due to compatibility issues, with only a small amount of other rubber added, while large additions can significantly reduce the performance of silicone or fluorosilicone rubber. Some researchers have also attempted to improve damping by adding copolymers of silicone and non-silicone materials as damping agents, but this still results in performance degradation after adding large amounts, particularly with a significant decrease in mechanical properties and heat resistance.

[0004] Therefore, there is an urgent need in this field for a rubber sound membrane that can improve the damping of the rubber without reducing its other properties.

[0005] [Summary of the invention]

[0006] In order to solve the above technical problems, the present invention provides a rubber sound diaphragm, which contains a distortion improver in an amount of 1% to 40% by mass. The distortion improver is a high molecular weight polymer with a -Si-O- structure in the main chain. The distortion improver contains side groups and / or side chains. The number average molecular weight of the side chains of the distortion improver is 60 to 20,000. The end groups and side groups of the distortion improver each include at least one of methyl, ethyl, propyl, butyl, phenyl, naphthyl, hydroxyl, amino, ester, and amide groups. At least one of the end groups, side groups, and side chains of the distortion improver has a special chemical crosslinking point in an amount of 0.03% to 30% by mass.

[0007] Preferably, the special chemical cross-linking points include at least one of silicon-hydrogen bonds, silicon-chloride bonds, hydroxyl groups, carboxyl groups, isocyanate groups, acyl chloride groups, amino groups, double bonds, triple bonds, and epoxy groups.

[0008] Preferably, the number average molecular weight of the distortion improvement agent is 1,000 to 1,000,000.

[0009] Preferably, the preparation method of the distortion improver includes: taking 100 parts of epoxy polysiloxane and 200-400 parts of toluene by mass, adding them to a reactor and dissolving them evenly, adding 0.1-60 parts of maleic anhydride, reacting at 70-80°C for 12-24 hours, and removing the solvent to obtain the distortion improver.

[0010] Preferably, the rubber sound membrane further contains main rubber, reinforcing filler, vulcanizing agent and vulcanizing auxiliary agent.

[0011] Preferably, the main rubber includes at least one of silicone rubber, fluorosilicone rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, styrene-butadiene rubber, natural rubber, chloroprene rubber, EPDM rubber, EPDM rubber, butadiene rubber, acrylate rubber, ethylene acrylate rubber, and chlorosulfonated polyethylene.

[0012] The rubber sound diaphragm provided by the present invention contains a special distortion-modifying agent. Specifically, the distortion-modifying agent is a polymer with a -Si-O- structure in its main chain and contains pendant groups and / or side chains. Furthermore, at least one of the end groups, pendant groups, and side chains of the distortion-modifying agent has a special chemical crosslinking point, which allows its damping performance to be controlled by the end groups, pendant groups, and side chains. The -Si-O- structure in the main chain allows it to retain the excellent heat resistance of silicone rubber and fluorosilicone rubber while ensuring excellent compatibility with the main rubber. The high molecular weight ensures a certain degree of strength. The special chemical crosslinking points prevent it from flowing at high temperatures, thus improving its heat resistance. In general, this distortion improver has the same excellent heat resistance as silicone rubber and fluorosilicone rubber, excellent compatibility, and sufficiently high strength to avoid the combined effect of chemical cross-linking points that cause high-temperature flow. This distortion improver can be widely used in rubber sound membranes without sacrificing the physical properties of the main rubber. At the same time, it can significantly improve the distortion performance of the rubber sound membrane and improve the demolding performance of the rubber sound membrane.

[0013] In another aspect, the present invention further provides a sound-generating device comprising the aforementioned rubber diaphragm. At low frequencies, the device significantly reduces THD, improving sound quality while having little effect on F0 and frequency response. The device can be used in mobile phones, headphones, smartwatches, tablets, laptops, desktop computers, speakers, televisions, automobiles, and other fields.

Brief Description of the Drawings

[0014] FIG. 1 is a THD curve diagram of a loudspeaker made using a conventional rubber diaphragm and the rubber diaphragm provided by the present invention. [Specific implementation method]

[0015] The present invention will be described below with reference to the accompanying drawings and embodiments.

[0016] Preparation of distortion improvement agent:

[0017] 100 parts of epoxy polysiloxane and 200-400 parts of toluene were added into a reactor and dissolved uniformly. 0.1-60 parts of maleic anhydride were added and reacted at 70-80° C. for 12-24 hours. The solvent was removed to obtain a distortion improving agent.

[0018] Taking Maitu silicone compound LSR2759 as an example, add 10 parts of distortion improver, 3 parts of double 25, and 2 parts of TIAC. Then use a diaphragm press to press the rubber diaphragm at 190-200℃ and 0.1-0.5MPa for 1-20 minutes to press the diaphragm. Then assemble the diaphragm into the speaker and test its distortion (THD) performance.

[0019] Sound-generating devices including the rubber diaphragm provided by the present invention can be, but are not limited to, speakers, receivers, and other sound-generating devices. The speaker is used as an example for illustration, and this is not intended to limit the scope of application of the present invention. A speaker was fabricated using the rubber diaphragm provided by the present invention, and its THD was tested.

[0020] The following is further described by way of examples. It should be understood that the specific examples described herein are only used to explain the present invention, rather than to limit the present invention.

[0021] Example 1

[0022] Preparation of distortion improving agent 1:

[0023] 100 parts by mass of epoxy polysiloxane and 200 parts by mass of toluene were added to a reactor and dissolved uniformly. 5 parts of maleic anhydride were added and reacted at 80° C. for 18 hours. The solvent was removed to obtain a distortion improver 1.

[0024] Taking Momentive silicone rubber compound LSR2759 as an example, 10 parts of distortion improver 1, 3 parts of double 25, and 2 parts of TIAC were added to prepare a rubber compound containing distortion improver 1. Then, a sound film press was used to hot press for 10 minutes at 200°C and 0.2MPa to press the rubber sound film. The sound film was assembled into a speaker and its distortion (THD) performance was tested. The results are shown in Figure 1.

[0025] Example 2

[0026] Preparation of distortion improving agent 2:

[0027] 100 parts by mass of epoxy polysiloxane and 200 parts by mass of toluene were added to a reactor and dissolved uniformly. 8 parts of maleic anhydride were added and reacted at 80° C. for 24 hours. The solvent was removed to obtain a distortion improver 2.

[0028] Taking Momentive silicone rubber compound LSR2759 as an example, 10 parts of distortion improver 2, 3 parts of double 25, and 2 parts of TIAC were added to prepare a rubber compound containing distortion improver 2. Then, a sound film press was used to hot press for 10 minutes at 200°C and 0.2MPa to press the rubber sound film. The sound film was assembled into a speaker and its distortion (THD) performance was tested. The results are shown in Figure 1.

[0029] Example 3

[0030] Preparation of distortion improving agent 3:

[0031] 100 parts by mass of epoxy polysiloxane and 200 parts by mass of toluene were added to a reactor and dissolved uniformly. 10 parts of maleic anhydride were added and reacted at 80° C. for 24 hours. The solvent was removed to obtain a distortion improver 3.

[0032] Taking Momentive silicone rubber compound LSR2759 as an example, 10 parts of distortion improver 3, 3 parts of double 25, and 2 parts of TIAC were added to prepare a rubber compound containing distortion improver 3. Then, a sound film press was used to hot press for 10 minutes at 200°C and 0.2MPa to press the rubber sound film. The sound film was assembled into a speaker and its distortion (THD) performance was tested. The results are shown in Figure 1.

[0033] As shown in FIG1 , the loudspeaker using the rubber diaphragm provided by the present invention can significantly improve the distortion characteristics (THD) of the low-frequency sound-generating device.

[0034] In the low-frequency band, the THD of the sound-generating device is significantly reduced, the sound quality is improved, and at the same time, F0 and frequency response are almost unaffected. The sound-generating device can be applied to mobile phones, headphones, smart watches, tablet computers, laptops, desktop computers, speakers, televisions, automobiles and other fields.

[0035] While some specific embodiments of the present invention have been described in detail above, those skilled in the art will appreciate that the above embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art will appreciate that any modifications, equivalent substitutions, and improvements to the above embodiments, without departing from the spirit and principles of the present invention, are intended to be within the scope of protection of the present invention.

Claims

1. A rubber sound film, characterized in that, the rubber sound film contains a distortion improver with a mass percentage of 1% to 40%, the distortion improver is a high molecular polymer with a -Si-O- structure in the main chain, the distortion improver contains side groups and / or side chains, the number average molecular weight of the side chains of the distortion improver is 60 to 20,000, and the end groups and side groups of the distortion improver each include at least one of methyl, ethyl, propyl, butyl, phenyl, naphthyl, hydroxyl, amino, ester group, amide group, wherein at least one of the end groups, side groups, and side chains of the distortion improver has a special chemical crosslinking point with a mass percentage of 0.03% to 30%.

2. The rubber sound film according to claim 1, characterized in that, the special chemical crosslinking point includes at least one of silicon-hydrogen bond, silicon chloride, hydroxyl, carboxyl, isocyanate group, acyl chloride, amino, double bond, triple bond, epoxy.

3. The rubber sound film according to claim 1, characterized in that, the number average molecular weight of the distortion improver is 1,000 to 1,000,000.

4. The rubber sound film according to claim 1, characterized in that, the preparation method of the distortion improver includes: by mass, taking 100 parts of epoxy group polysiloxane and 200 to 400 parts of toluene, adding them to a reaction kettle and dissolving evenly, adding 0.1 to 60 parts of maleic anhydride, reacting at 70 to 80 °C for 12 to 24 h, and removing the solvent to obtain the distortion improver.

5. The rubber sound film according to claim 1, characterized in that, the rubber sound film further contains a main rubber, a reinforcing filler, a vulcanizing agent, and a vulcanization aid.

6. The rubber sound film according to claim 5, characterized in that, the main rubber includes at least one of silicone rubber, fluorosilicone rubber, nitrile rubber, hydrogenated nitrile rubber, butyl rubber, styrene-butadiene rubber, natural rubber, chloroprene rubber, ethylene-propylene-diene monomer rubber, ethylene-propylene rubber, cis-butadiene rubber, acrylate rubber, ethylene-acrylate rubber, chlorosulfonated polyethylene.

7. A sounding device, characterized in that, the sounding device includes the rubber sound film according to any one of claims 1 to 6.

8. A product applying the sounding device according to claim 7, characterized in that, the product includes one of a mobile phone, an earphone, a smart watch, a tablet computer, a notebook computer, a desktop computer, a speaker, a television, an automobile.

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