Rubber sound film, and sound production device and use thereof

Abstract

A rubber sound film, and a sound production device and a use thereof. The rubber sound film contains 0.2-60% by mass of a distortion improver. The distortion improver is a block polymer, and an end group or at least one block component of the distortion improver comprises 0.02-25% by mass of a special chemical crosslinking site at which a chemical reaction can occur. The number average molecular weight of each block of the distortion improver is from 300 to 100,000. The distortion improver can be accurately prepared by means of living polymerization or the main body structure can be accurately prepared by means of living polymerization. The rubber sound film contains the distortion improver, and the structure and the content of the special chemical crosslinking site of the distortion improver are accurately controllable, so that the position, height, and width of a damping peak thereof are accurately controllable, and the damping characteristics of the obtained rubber sound film are accurately controllable. When the rubber sound film is applied to the sound production device, the distortion in a low-frequency band can be accurately reduced while good frequency response characteristics are maintained, and the rubber sound film has high controllability, stable performance, and extremely board application range.

Description

A rubber sound membrane and sound-generating device and their applications

Technical field

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

[0002] With the rapid development of electronic technology and the improvement of people's living standards, consumers are demanding higher and higher sound quality from sound-generating devices. Reducing the distortion (THD) of sound-generating devices within specific frequency bands and improving their sound quality are gaining increasing attention from researchers. As a key component of sound-generating devices, diaphragm materials can significantly reduce THD by manipulating their structure and properties.

[0003] Due to their unique physical properties, rubber diaphragms are gaining popularity in high-end sound-generating devices. The question of how to precisely improve the performance of rubber diaphragms and reduce the THD of sound-generating devices is gaining increasing attention.

[0004] Therefore, there is an urgent need in the art for a rubber diaphragm with precisely controllable damping, thereby accurately reducing the distortion (THD) of the speaker.

[0005] [Summary of the invention]

[0006] The object of the present invention is to provide a rubber diaphragm and a sound-generating device and their applications. The rubber diaphragm has a precise structure, which can accurately control the damping performance of the rubber diaphragm, thereby accurately reducing the distortion (THD) of the sound-generating device.

[0007] The technical solutions of the present invention are as follows:

[0008] In the first aspect, the present invention discloses a rubber sound membrane, which includes a distortion improver with a mass percentage of 0.2-60%, wherein the distortion improver is a block polymer, and the end group or at least one block component of the distortion improver includes a special chemical cross-link capable of chemical reaction with a mass fraction of 0.02-25%; the number average molecular weight of each block of the distortion improver is 300-100000; the distortion improver can be precisely prepared by active polymerization or the main structure can be precisely prepared by active polymerization.

[0009] Preferably, the block polymer is a diblock, triblock or multiblock polymer, and each block synergistically adjusts the distortion performance; the components of the block polymer are regularly arranged in the form of molecular segments.

[0010] Preferably, the block polymer has a number average molecular weight of 1,000-1,000,000.

[0011] Preferably, the living polymerization includes one of living free radical polymerization, anionic polymerization, cationic polymerization or coordination polymerization.

[0012] Preferably, the special chemical crosslinking points include one or more of a double bond, a triple bond, an isocyanate group, a silicon-hydrogen bond, a silicon-chloro bond, an azide group, an epoxy group, a nitrile group, a siloxane group, a carboxyl group, a hydroxyl group, an amide group, an amino group, an acyl chloride bond or an anhydride group.

[0013] Preferably, the preparation method of the distortion improver includes the steps of: providing a macromolecular chain transfer agent; uniformly mixing the macromolecular chain transfer agent with 2-ethylhexyl acrylate, an initiator and a first solvent, and after the reaction is completed under first conditions, removing the first solvent to obtain an intermediate polymer; uniformly mixing the obtained intermediate polymer with hydroxyethyl acrylate, an initiator and a second solvent, and then reacting and combining under the first conditions, and removing the second solvent to obtain the distortion improver.

[0014] Preferably, the rubber sound membrane component further includes, by mass, 150-200 parts of main rubber, 2-5 parts of reinforcing filler, 1.5-2.5 parts of vulcanizing agent, 2-5 parts of co-vulcanizing agent, 2-3.5 parts of antioxidant and 2-3 parts of release agent.

[0015] In a second aspect, the present invention provides a sound-generating device comprising a voice coil, a magnetic circuit system, a supporting structure, and the rubber diaphragm according to any one of claims 1 to 7.

[0016] In a third aspect, the present invention provides an application of the above-mentioned sound-generating device in a terminal product.

[0017] The beneficial effects of the present invention are:

[0018] The rubber diaphragm of the present invention includes a distortion-modifying agent, a block polymer whose structure and the content of the specific chemical crosslinking points are precisely controllable. This allows for precise control of the position, height, and width of the damping peak, and thus the damping properties of the resulting rubber diaphragm. When applied to sound-generating devices, the resulting rubber diaphragm can precisely reduce low-frequency distortion (THD) while maintaining excellent frequency response characteristics. Furthermore, it offers strong controllability, stable performance, and a wide range of applications.

Brief Description of the Drawings

[0019] Figure 1 shows the symmetrical trithiocarbonate obtained in Example 1. 1 H NMR spectrum;

[0020] FIG. 2 is a THD curve diagram of loudspeakers equipped with the rubber diaphragms obtained in Examples 1-3 of the present invention and a rubber diaphragm in the prior art. [Specific implementation method]

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] In the first aspect, the present invention discloses a rubber sound membrane, which includes a distortion improver with a mass percentage of 0.2-60%, and the distortion improver is a block polymer. The end group of the distortion improver or at least one block component includes a mass fraction of 0.02-25% of special chemical cross-linking points that can undergo chemical reactions, that is, the end group of the block polymer or a certain block or two blocks or multiple block components include a mass fraction of 0.02%-25% of special chemical cross-linking points that can undergo chemical reactions; the number average molecular weight of each block of the distortion improver is 300-100000; the distortion improver can be precisely prepared by active polymerization or the main structure can be precisely prepared by active polymerization.

[0023] Because the block polymer is prepared by active polymerization to ensure that the molecular structure is precisely controllable, the structure of the obtained distortion improver block polymer is precisely controllable, and its damping peak position, height, width and narrowness are precisely controllable. At the same time, its special chemical cross-linking point content is precisely controllable, and the damping performance of the prepared rubber sound membrane is precisely controllable. The loudspeaker using the rubber sound membrane of the present invention can accurately reduce the distortion (THD) in the low frequency band while maintaining good frequency response characteristics. At the same time, it has strong controllability, stable performance and a wide range of applications. In the sound-generating device using the rubber sound membrane of the present invention, in a specific low-frequency band, the THD of the sound-generating device is accurately and significantly reduced, the sound quality is improved, and at the same time, it has almost no effect on F0 and frequency response. Sound-generating devices have been used in mobile phones, tablets, computers, headphones, cars, televisions, audio equipment and other fields. Therefore, the present invention has broad application prospects.

[0024] Preferably, the block polymer is a diblock, triblock or multiblock polymer, and each block synergistically adjusts the distortion performance; the components of the block polymer are regularly arranged in the form of molecular segments.

[0025] Preferably, the block polymer has a number average molecular weight of 1,000-1,000,000.

[0026] Preferably, the living polymerization includes one of living free radical polymerization, anionic polymerization, cationic polymerization or coordination polymerization.

[0027] Preferably, the special chemical crosslinking points include one or more of a double bond, a triple bond, an isocyanate group, a silicon-hydrogen bond, a silicon-chloro bond, an azide group, an epoxy group, a nitrile group, a siloxane group, a carboxyl group, a hydroxyl group, an amide group, an amino group, an acyl chloride bond or an anhydride group.

[0028] Preferably, the preparation method of the distortion improving agent comprises the steps of:

[0029] Primary polymerization: providing a macromolecular chain transfer agent; uniformly mixing the macromolecular chain transfer agent with a polymerization monomer, 2-ethylhexyl acrylate, an initiator, and a first solvent; after the reaction is completed under the first conditions, removing the first solvent to obtain an intermediate polymer;

[0030] Secondary Polymerization: The resulting intermediate polymer is uniformly mixed with hydroxyethyl acrylate, an initiator, and a second solvent, and then reacted and combined under the first conditions. The second solvent is then removed to obtain the distortion-reducing agent. Specifically, the first conditions include: nitrogen flow for 20 minutes, heating to 75°C, and then reacting under aeration and reflux conditions for 1-5 hours.

[0031] The preparation of the intermediate polymer comprises, by weight, 100 parts of a macromolecular chain transfer agent, 25-30 parts of 2-ethylhexyl acrylate, 0.05-0.15 parts of an initiator AIBN, and 200 parts of a first solvent;

[0032] 100 parts of intermediate polymer, 0.1-0.5 parts of cross-linking agent, 0.001-0.005 parts of initiator AIBN, 150 parts of second solvent; the cross-linking agent is preferably hydroxyethyl acrylate.

[0033] Preferably, the rubber sound membrane component further includes, by mass, 150-200 parts of main rubber, 2-5 parts of reinforcing filler, 1.5-2.5 parts of vulcanizing agent, 2-5 parts of co-vulcanizing agent, 2-3.5 parts of antioxidant and 2-3 parts of release agent.

[0034] In a second aspect, the present invention provides a sound-generating device comprising the rubber diaphragm, voice coil, magnetic circuit system and supporting structure as described above.

[0035] In a third aspect, the present invention provides an application of the above-mentioned sound-generating device in a terminal product, which includes a mobile phone, tablet, earphones, speakers, smartwatch, computer, speaker, television, or car.

[0036] Example 1

[0037] S1, preparation of high-purity RAFT chain transfer agent symmetric trithiocarbonate. The synthetic route of symmetric trithiocarbonate is as follows:

[0038] Including steps:

[0039] S11, 100 parts by mass of carbon disulfide, 400 parts by mass of chloroform, 200 parts by mass of acetone, 10 parts by mass of tetrabutylammonium hydrogen sulfate, and 400 parts by mass of toluene were stirred uniformly at room temperature;

[0040] S12, controlling the temperature in an ice bath, slowly adding 800 parts of a 50 wt% sodium hydroxide solution to the solution, and gradually changing the solution from colorless to reddish brown; specifically, controlling the temperature in the ice bath is to react the mixed system in step S11 in an ice-water mixture;

[0041] S13, stirring overnight, forming a dark red oily layer with a strong odor on the upper layer and a khaki turbid liquid on the lower layer;

[0042] S14, slowly add excess dilute hydrochloric acid dropwise to the reaction solution, pay attention to ice bath temperature control to prevent temperature rise; let it stand, filter to obtain a yellowish-brown solid with a strong odor; after washing with toluene / acetone solution, the mass ratio of toluene to acetone is 4:1, filter to obtain a yellow solid; after vacuum drying, use nuclear magnetic resonance and mass spectrometry to characterize its structure, the results are shown in Figure 1, Figure 1 a represents b represents -COOH, DMSO represents the solvent peak, and the coordinate ppm is the chemical shift unit; this shows that we have successfully prepared a high-purity RAFT chain transfer agent symmetrical trithiocarbonate.

[0043] S2, preparation of a macromolecular chain transfer agent, comprising the steps of:

[0044] Weigh 100 parts of styrene (by mass), 1 part of the symmetrical trithiocarbonate prepared by the above preparation method, 0.1 part of the initiator AIBN, and 150 parts of the solvent, add them to a reactor and mix evenly, purge with nitrogen for 20 minutes, heat to 75°C, react under ventilation and reflux condensation conditions for 1-5 hours, and remove the solvent to obtain the desired polystyrene.

[0045] S3, the preparation of the distortion improving agent adopts free radical polymerization, comprising the steps of:

[0046] S31, primary polymerization: Weigh 100 parts of the obtained polystyrene, 30 parts of 2-ethylhexyl acrylate, 0.05 parts of initiator AIBN, and 200 parts of solvent, by mass, add them to a reactor and mix well. Flow nitrogen for 20 minutes, and heat to 75°C. React under ventilation and reflux condensation for 1-5 hours, and remove the solvent to obtain an intermediate polymer.

[0047] S32, secondary polymerization: Weigh 100 parts by mass of the obtained intermediate polymer, 0.1 parts by mass of cross-linking agent hydroxyethyl acrylate, 0.001 parts by mass of initiator AIBN, and 150 parts by mass of the solvent, add them into a reactor, mix them evenly, pass nitrogen through for 20 minutes, and heat to 75°C; react for 1-5 hours under ventilation and reflux condensation conditions, and remove the solvent to obtain a distortion improver, which is recorded as distortion improver 1.

[0048] Example 2

[0049] Compared with Example 1, the difference of Example 2 lies in the different preparation of the distortion improving agent, specifically:

[0050] Weigh 100 parts of polystyrene, 25 parts of 2-ethylhexyl acrylate, 0.01 parts of initiator AIBN, and 200 parts of solvent, by mass, add them to a reactor and mix evenly. Flow nitrogen for 20 minutes and heat to 75°C. React under ventilation and reflux condensation conditions for 1-5 hours, and remove the solvent to obtain the desired intermediate polymer.

[0051] Weigh 100 parts of the intermediate polymer, 0.2 parts of hydroxypropyl acrylate, 0.002 parts of the initiator AIBN, and 150 parts of the solvent, by mass, add them to a reactor and mix evenly. Flow nitrogen for 20 minutes and heat to 75°C. React under ventilation and reflux condensation for 1-5 hours. Remove the solvent to obtain a distortion improver, which is recorded as distortion improver 2.

[0052] Example 3

[0053] Compared with Example 1, the difference of Example 3 lies in the different preparation of the distortion improving agent, specifically:

[0054] Add 100 parts of polystyrene, 35 parts of 2-ethylhexyl acrylate, 0.15 parts of initiator AIBN, and 200 parts of solvent, by mass, to a reactor and mix well. Flow nitrogen for 20 minutes and heat to 75°C. React under ventilation and reflux condensation for 1-5 hours, and remove the solvent to obtain the desired intermediate polymer.

[0055] Weigh 100 parts of the intermediate polymer, 0.3 parts of hydroxybutyl acrylate, 0.004 parts of initiator AIBN, and 150 parts of the solvent, by mass, add them to a reactor and mix evenly. Flow nitrogen for 20 minutes and heat to 75°C. React under ventilation and reflux condensation for 1-5 hours. Remove the solvent to obtain a distortion improver, which is recorded as distortion improver 3.

[0056] Example 4

[0057] Taking AEM rubber as the main rubber as an example, the distortion improvers obtained in Examples 1-3, the reinforcing filler, the vulcanizing agent, the co-vulcanizing agent, the antioxidant and the release agent as shown in Table 1 were mixed evenly to obtain a rubber compound. The compound was then pressed or coated into a thin sheet of about 100 microns using a rubber calender, a flat vulcanizer or a coater. The rubber diaphragm was hot-pressed for 10 minutes at 200°C and 0.2 MPa using a diaphragm press to obtain the rubber diaphragm in the prior art and the rubber diaphragms containing distortion improvers 1, 2 and 3. These were respectively applied to speakers to obtain corresponding speakers, and then their distortion (THD) performance was tested. The results are shown in Figure 2.

[0058] As shown in Figure 2, the speaker fabricated with the rubber diaphragm of the present invention exhibits lower total harmonic distortion (THD) at low frequencies than speakers equipped with conventional rubber diaphragms. This significantly reduces the THD of the sound-generating device, improving sound quality while maintaining minimal impact on F0 and frequency response. Sound-generating devices are already used in mobile phones, tablets, computers, headphones, automobiles, televisions, and audio systems, and therefore, the present invention has broad application prospects.

[0059] The above description is only an embodiment of the present invention. It should be pointed out that those skilled in the art can make improvements without departing from the creative concept of the present invention, but these improvements all fall within the scope of protection of the present invention.

Claims

1. A rubber sound film, characterized in that: It includes a distortion improver with a mass percentage of 0.2-60%; the distortion improver is a block polymer, and the end group or at least one block component of the distortion improver includes a special chemical crosslinking point capable of undergoing a chemical reaction with a mass fraction of 0.02-25%; the number-average molecular weight of each block of the distortion improver is 300-100,000; the distortion improver can be precisely prepared by living polymerization or the main structure can be precisely prepared by living polymerization.

2. The rubber sound film according to claim 1, wherein: The block polymer is a diblock, triblock or multi-block polymer, and each block synergistically adjusts the distortion performance; each component of the block polymer is regularly arranged in the form of molecular segments.

3. The rubber sound film according to claim 1, characterized in that: The number-average molecular weight of the block polymer is 1,000-1,000,000.

4. The rubber sound film according to claim 1, characterized in that: The living polymerization includes one of living radical polymerization, anionic polymerization, cationic polymerization or coordination polymerization.

5. The rubber sound film according to claim 1, wherein: The special chemical crosslinking point includes one or more of a double bond, a triple bond, an isocyanate group, a silicon-hydrogen bond, a silicon-chlorine bond, an azide group, an epoxy group, a nitrile group, a siloxane, a carboxyl group, a hydroxyl group, an amide group, an amino group, an acyl chloride bond or an acid anhydride group.

6. The rubber sound film according to claim 1, wherein: The preparation method of the distortion improver includes the steps of: providing a macromolecular chain transfer agent; uniformly mixing the macromolecular chain transfer agent with 2-ethylhexyl acrylate, an initiator and a first solvent, and after the reaction is completed under the first conditions, removing the first solvent to obtain an intermediate polymer; uniformly mixing the obtained intermediate polymer with 2-hydroxyethyl acrylate, an initiator and a second solvent, and then reacting and combining under the first conditions, and removing the second solvent to obtain the distortion improver.

7. The rubber sound film according to claim 1, wherein: By mass, the rubber voice coil membrane component further includes 150-200 parts of a main rubber, 2-5 parts of a reinforcing filler, 1.5-2.5 parts of a vulcanizing agent, 2-5 parts of a vulcanization aid, 2-3.5 parts of an antioxidant and 2-3 parts of a mold release agent.

8. A sound generating device, characterized in that: It includes a voice coil, a magnetic circuit system, a support structure, and a rubber voice coil membrane as described in any one of claims 1-7.

9. Application of a sound generating device as described in claim 8 in a terminal product.

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