WO2021135871A1 - Sound absorbing material preparation method, sound absorbing material, sound producing unit, and electronic device - Google Patents

Abstract

A sound absorbing material preparation method, a sound absorbing material, a sound producing unit, and an electronic device. The sound absorbing material is prepared by mixing an amorphous activated carbon particle containing a hydrophobic layer and a high molecular polymer binder; the amorphous activated carbon particle containing a hydrophobic layer comprises an activated carbon particle core and a hydrophobic layer covering the activated carbon particle core; the hydrophobic layer is made of any one of a zeolite material, an aerogel material, and a porous organic polymer material; the hydrophobic layer has a thickness of 0.1-10 µm; the amorphous activated carbon particle containing a hydrophobic layer has a loose pore structure inside, and the pore structure comprises nano-scale micropores and mesopores; the particle size of the amorphous activated carbon particle containing a hydrophobic layer is 0.1-100 µm, and the particle size of the sound absorbing material is 50-1000 µm. The prepared sound absorbing material can be used for reducing the resonant frequency of a sound producing unit.

Description

Preparation method of sound-absorbing material, sound-absorbing material, sound generating device and electronic equipment Technical field

The present invention relates to the technical field of material preparation. More specifically, the present invention relates to a method for preparing a sound-absorbing material, a sound-absorbing material, a sound generating device and an electronic device.

Background technique

With the rapid development of electroacoustic technology, various electroacoustic products emerge in endlessly. As an energy converter that converts electrical signals into sound signals, the sounding device is an indispensable device in electroacoustic products. Nowadays, sound generating devices have been used in various types of terminal electronic devices, such as mobile phones, tablet computers, notebook computers, VR devices, AR devices, smart watches, and smart wearables, with a wide range of applications.

As far as the prior art is concerned, a sound generating device usually includes a housing and a speaker unit arranged in an inner cavity of the housing, and the space of the inner cavity of the housing is divided into a front sound cavity and a rear sound cavity by the speaker unit. In order to improve the acoustic performance of the sound emitting device, such as reducing the resonant frequency F0 of the sound emitting device, a sound-absorbing material is usually arranged in the rear acoustic cavity. The sound-absorbing material can absorb part of the sound energy, which is equivalent to expanding the volume of the rear acoustic cavity, thereby achieving the effect of reducing the resonance frequency F0 of the sound generating device. Traditional sound-absorbing materials are foamed foams, such as polyurethane and melamine. With the increasingly thinner and lighter electronic equipment, the volume of the acoustic cavity is continuously compressed. Traditional foam-type foam sound-absorbing materials are difficult to reduce the resonant frequency F0 of the sounding device to the required value, which cannot guarantee the middle of the sounding device. Low frequency sound quality.

In recent years, technicians have discovered through research that the porous non-foaming material is filled into the rear acoustic cavity of the sounding device, and the porous non-foaming material is used to rapidly adsorb and desorb the gas in the rear acoustic cavity, which can increase the resonance space virtually. Large, can effectively reduce the resonant frequency F0 of the sound device. At present, porous non-foaming materials are widely used, such as activated carbon materials and zeolite materials with a high silicon-to-aluminum ratio. Activated carbon material is easy to absorb water and easily affects the reduction of the resonance frequency F0 of the sound generating device. Zeolite materials with a high silicon-to-aluminum ratio have higher requirements for the types and grades of synthetic raw materials, the synthesis process and the post-treatment process are more complicated, the output rate is lower, and the production cost is higher.

Therefore, it is necessary to study a new sound-absorbing material to solve the problems existing in the prior art.

Summary of the invention

An object of the present invention is to provide a new technical solution for the preparation method of sound-absorbing material, sound-absorbing material, sound generating device and electronic equipment.

According to the first aspect of the present invention, there is provided a method for preparing a sound-absorbing material, the sound-absorbing material is prepared by mixing amorphous activated carbon particles containing a hydrophobic layer and a polymer binder;

The amorphous activated carbon particles containing a hydrophobic layer include an activated carbon particle core and a hydrophobic layer coated on the outer surface of the activated carbon particle core; wherein the material of the hydrophobic layer is zeolite material, aerogel material, porous organic polymer Any one of the materials, the thickness of the hydrophobic layer is 0.1-10 μm;

The amorphous activated carbon particles containing the hydrophobic layer have a loose pore structure inside, and the pore structure includes nano-scale micropores and mesopores; the particle diameter of the amorphous activated carbon particles containing the hydrophobic layer is 0.1-100 μm, so The particle size of the sound-absorbing material is 50-1000 μm.

Optionally, the particle size of the amorphous activated carbon particles containing the hydrophobic layer is 0.2-20 μm, and the particle size of the sound-absorbing material is 100-450 μm.

Optionally, the mass ratio of the hydrophobic layer in the amorphous activated carbon particles containing the hydrophobic layer is 1-50% by weight, and the mass of the activated carbon particle core in the amorphous activated carbon particles containing the hydrophobic layer accounts for The ratio is 50-99wt%.

Optionally, the activated carbon particle core material includes carbon element, hydrogen element and oxygen element;

The activated carbon particle core material contains a chaotic layer structure formed by random accumulation of molecular fragments of two-dimensional graphite layers and/or three-dimensional graphite crystallites.

Optionally, the pore diameter of the micropore is 0.5-2 nm, and the pore diameter of the mesopore is 2-3.5 nm.

Optionally, the mass ratio of the high molecular polymer binder in the sound-absorbing material is 1-10 wt%.

Optionally, the high molecular polymer adhesive includes a polyacrylic adhesive, a polyvinyl alcohol adhesive, a polystyrene adhesive, a polyurethane adhesive, and a polyvinyl acetate adhesive. At least one of the adhesives and polybutadiene rubber adhesives.

Optionally, the cumulative pore volume of the amorphous activated carbon particles containing the hydrophobic layer is 0.6-5 cm ³ /g.

Optionally, the bulk density of the sound-absorbing material is 0.05-0.8 g/cm ³ .

According to a second aspect of the present invention, a sound-absorbing material is provided. The sound-absorbing material is prepared according to the method for preparing the sound-absorbing material as described above.

According to a third aspect of the present invention, a sound generating device is provided. The sound generating device includes:

A housing in which a containing cavity is formed;

A vibration component, the vibration component is arranged in the housing;

The accommodating cavity is provided with the above-mentioned sound-absorbing material.

According to a fourth aspect of the present invention, an electronic device is provided. The electronic equipment includes the sound emitting device as described above.

The preparation method of the sound-absorbing material provided by the embodiment of the present invention has the characteristics of simple preparation process and easy realization, and does not increase the production cost. The prepared sound-absorbing material is used in a sound-generating device, can well reduce the resonance frequency F0 of the sound-generating device, and improve the mid- and low-frequency sound quality of the sound-generating device, so that the sound-generating device can have good acoustic performance. The technical task to be achieved or the technical problem to be solved by the present invention is never thought of or unexpected by those skilled in the art, so the present invention is a new technical solution.

Through the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings, other features and advantages of the present invention will become clear.

Detailed ways

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

The following description of at least one exemplary embodiment is actually only illustrative, and in no way serves as any limitation to the present invention and its application or use.

The technologies, methods, and equipment known to those of ordinary skill in the relevant fields may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be regarded as part of the specification.

In all examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiment may have different values.

It should be noted that similar reference numerals and letters indicate similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further discussed in the subsequent drawings.

According to an embodiment of the present invention, a method for preparing a sound-absorbing material is provided. The sound-absorbing material prepared by the preparation method can be used in a variety of different types of sound-generating devices, can achieve the effect of reducing the resonance frequency F0 of the sound-generating device, and can well improve the mid- and low-frequency sound quality of the sound-generating device.

An embodiment of the present invention provides a method for preparing a sound-absorbing material. The sound-absorbing material is prepared by mixing amorphous activated carbon particles containing a hydrophobic layer and a high molecular polymer binder. Wherein, the amorphous activated carbon particles containing a hydrophobic layer include an activated carbon particle core and a hydrophobic layer coated on the outer surface of the activated carbon particle core. The material of the hydrophobic layer is any one of zeolite material, aerogel material, and porous organic polymer material. The thickness of the hydrophobic layer is 0.1-10 μm. The amorphous activated carbon particles containing a hydrophobic layer contain a chaotic layer structure formed by the random accumulation of molecular fragments of two-dimensional graphite layers and/or three-dimensional graphite crystallites; and the amorphous activated carbon particles containing a hydrophobic layer have inside A loose pore structure including nano-scale micropores and mesopores. Wherein, the particle size of the amorphous activated carbon particles containing the hydrophobic layer ranges from 0.1 μm to 100 μm. The prepared sound-absorbing material is in the form of dispersed particles, and the particle size of the sound-absorbing material ranges from 50 μm to 1000 μm.

The preparation method of the sound-absorbing material provided by the present invention has a relatively simple process flow, easy implementation, no increase in production cost, and relatively high output rate, which is very suitable for mass production in industry and is very suitable for popularization and application. In the preparation method provided by the present invention, in particular, amorphous activated carbon particles containing a hydrophobic layer are used, which is different from ordinary carbon particles in that the activated carbon particles are used as the core and the outer surface of the activated carbon particle core is coated with waterproof Formed by layers. Since the core of activated carbon particles contains a chaotic layer structure formed by the random accumulation of molecular fragments of two-dimensional graphite layers and/or three-dimensional graphite crystallites, the formed amorphous activated carbon particles containing a hydrophobic layer also have a corresponding chaotic layer structure. And it has a loose pore structure inside. When it is mixed with a high molecular polymer binder, the particle size range of the formed sound-absorbing material can be appropriately adjusted to meet the requirements of the sound-generating device for the size of the sound-absorbing material. After the sound-absorbing material prepared by the present invention is applied to a sound-generating device, the resonance frequency of the sound-generating device can be effectively reduced, the middle and low frequency sound quality of the sound-generating device can be improved, and the sound-generating device can have a good acoustic effect.

In the present invention, the high molecular polymer adhesive includes polyacrylic adhesives, polyvinyl alcohol adhesives, polystyrene adhesives, polyurethane adhesives, and polyvinyl acetate adhesives. At least one of adhesives and polybutadiene rubber adhesives. Those skilled in the art can flexibly choose and adjust according to specific needs. There is no restriction on this.

In the present invention, the particle size of the amorphous activated carbon particles containing the hydrophobic layer ranges from 0.1 μm to 100 μm, and the particle size is relatively small. In the present invention, a bonding method is also used to bond the high molecular polymer binder and the amorphous activated carbon particles containing the hydrophobic layer, and the bonded amorphous activated carbon particles containing the hydrophobic layer form the particle size. Larger particles are used to meet the requirements of the sound cavity after being filled into the sound generating device. It should be noted that the amount of the high-molecular polymer binder is not easy to be too large, and the mass proportion of the high-molecular polymer binder in the sound-absorbing material can be, for example, 1-10% by weight, so that the formed sound-absorbing material The material particles can have suitable size and good morphology.

Since the volume of the sounding device itself is relatively small, the subsequent acoustic cavity is usually narrower. Therefore, the size of the sound-absorbing material should also be reasonably controlled so that the sound-absorbing material can be filled into the sound generating device. If the particle size of the sound-absorbing material is large, it is not conducive to the filling of the sound-absorbing material. The invention controls the particle size of the sound-absorbing material to be 50 μm-1000 μm through screening. The particle size of the particles is distributed in a small interval, which reduces the difficulty of preparation, is easy to control, and is convenient for large-scale production. Moreover, in this range, it is very beneficial to the filling of sound-absorbing materials, and it is also suitable for most sound-producing devices, with strong versatility.

In the present invention, the particle size range of the amorphous activated carbon particles containing the hydrophobic layer is 0.1 μm-100 μm, and the particle size range of the sound-absorbing material is 50 μm-1000 μm. The particle size of the sound-absorbing material itself will have an impact on the packing density of the particles, which in turn will affect the effect of reducing the resonance frequency F0 of the sound-generating device. In most sound-generating devices, the aperture size of the isolation mesh used to encapsulate the sound-absorbing material is usually about 50μm. If the particle size of the sound-absorbing material is less than 50μm, the activated carbon sound-absorbing material particles are too small and easy to leak out, which will affect the sound production. The vocal unit in the device. This will seriously affect the effect of reducing the resonance frequency, and may also have a certain impact on the reliability of the sound generating device. If the particle size of the sound-absorbing material is greater than 1000 μm, the volume of the sound-absorbing material particles is relatively large, which will cause the gap between the particles to increase significantly. When it is placed in a sound generating device, the bulk density of the particles will be significantly reduced. Correspondingly, in the unit volume of the sound cavity behind the sound device, the amount of sound absorbing material that can be filled will relatively decrease. Therefore, the material that can produce the virtual expansion effect is reduced, and the effect of reducing the resonance frequency F0 will be weakened. In addition, the excessively large particle size can easily cause the amorphous activated carbon particles containing the hydrophobic layer to be unevenly heated during the carbonization process, the formed pore structure is imperfect, the cumulative pore volume becomes smaller, and the formed sound-absorbing material has the ability to adsorb gas, etc. The effective expansion capability will all show different degrees of reduction, which will eventually lead to a poor effect of reducing the resonance frequency F0.

Therefore, the particle size of the sound-absorbing material designed in the present invention ranges from 50 μm to 1000 μm. On the basis of basically meeting the performance requirements of reducing the resonance frequency F0, the usual filling requirements are also met. At the same time, within this particle size range, the sound-absorbing material is not easy to wear even if it is continuously working in the rear acoustic cavity of the sound generating device, can be used for a long time, and has the characteristics of good stability.

In a more preferred example of the present invention, the particle size of the amorphous activated carbon particles containing the hydrophobic layer ranges from 0.2 μm to 20 μm, and the particle size of the sound-absorbing material ranges from 100 μm to 450 μm. In this example, the particle size of the sound-absorbing material is smaller, which is suitable for use in some lighter and thinner micro-sounding devices, can adapt to a narrower rear acoustic cavity, and help to improve the acoustic performance of the micro-sounding device after use. In addition, when the particle size of the sound-absorbing material is in the range of 100 μm-450 μm, the performance of reducing the resonance frequency F0 of the sound device can reach the optimal level. In the present invention, by reasonably controlling the particle size of the sound-absorbing material particles, the optimal packing density and the effect of reducing the resonance frequency can be achieved.

In the present invention, the particle size of the sound-absorbing material is controlled to be 50 μm-1000 μm. The particle size of the sound-absorbing material will affect its own bulk density, and the size of the bulk density will affect the performance of air absorption. Wherein, the bulk density refers to the volume of particles packed into a container according to a certain method in a natural and loose state, including the volume of the particles and the volume of the voids between the particles. In other words, in a unit volume, the bulk density determines the amount of sound-absorbing material filled, and the amount of sound-absorbing material filled is related to the adsorption performance. If the particle size of the sound-absorbing material is too small, the bulk density will increase significantly. Under a certain volume, the mass of the sound-absorbing material that can be filled is relatively reduced, which will cause the performance of reducing the resonance frequency to be weakened. If the particle size of the sound-absorbing material is too large, the bulk density will be significantly reduced. Under a certain volume, an excessively large packing density will reduce the energy of the sound waves consumed when the sound-absorbing material particles in the space are forced to vibrate, which is equivalent to a decrease in the air acoustic compliance (Cma) in the volume of the rear acoustic cavity of the sound generating device. This will also cause a decrease in the performance of reducing the resonance frequency.

In the present invention, the bulk density of the sound-absorbing material may range from 0.05 to 0.8 g/cm ^{3, for example} . It should be noted that for the specific bulk density, those skilled in the art can also make appropriate adjustments through factors such as the shape and carbon content of the sound absorbing material, which is not limited by the present invention.

The amorphous activated carbon particle containing a hydrophobic layer of the present invention includes an activated carbon particle core and a hydrophobic layer coated on the outer surface of the activated carbon particle core. Specifically, the core of activated carbon particles is a porous adsorption material formed by carbonization and activation of a carbon-based material, which has good adsorption performance. Further improve the material's ability to absorb and release air. The core material of activated carbon particles includes three main elements: carbon, hydrogen, and oxygen. The carbon element is used to provide support to form a frame and pore structure.

The mass proportion of the hydrophobic layer in the amorphous activated carbon particles containing the hydrophobic layer is 1-50%, and the mass proportion of the activated carbon particle core in the amorphous activated carbon particles containing the hydrophobic layer is 50- 99%. In addition, the thickness of the hydrophobic layer may range from 0.1 μm to 10 μm, for example. The hydrophobic layer can effectively prevent the activated carbon particles from absorbing a large amount of water, which is beneficial to reduce the water absorption rate and avoid affecting the performance of the sound-absorbing material after being made into a sound-absorbing material. The material of the hydrophobic layer can be, for example, any one of zeolite material, aerogel material, and porous organic polymer material, which can reduce the water absorption rate of the formed material to less than 5%. For details, see Table 1 to Table 3 below.

Table 1 The hydrophobic layer is the relevant performance table of the zeolite material

Mass of zeolite coating (wt%)	0	0.1～5	5～20	20～40	30～50
Zeolite coating thickness (um)	0	0.1～2	2～4	2～6	4～10
F0 reduction effect (Hz)	170	165	160	158	150
Water absorption rate (%)	35%	twenty four%	16%	5%	2%

Table 2 The hydrophobic layer is the relevant performance table of the aerogel material

Table 3 The hydrophobic layer is a porous organic polymer material related performance table

It can be seen from Table 1 to Table 3 that when the outer surface of the activated carbon particle core is coated with a hydrophobic layer, the hydrophobic layer material, whether it is a zeolite material, aerogel material or a porous organic polymer material, will follow the coating layer. The increase in the mass percentage and the thickening of the thickness can reduce the resonance frequency, especially the water absorption rate can be significantly reduced, even the lowest can be reduced to 2%. It can be seen that the amorphous activated carbon particles containing a hydrophobic layer of the present invention do have a good effect in reducing the resonance frequency and absorption rate.

In the present invention, the amorphous activated carbon particle material containing a hydrophobic layer contains a two-dimensional graphite layer and/or a three-dimensional graphite crystallite. That is, the amorphous activated carbon particles containing a hydrophobic layer include a two-dimensional graphite layer structure and/or a chaotic layer structure formed by random accumulation of molecular fragments of three-dimensional graphite crystallites, and the amorphous activated carbon particles containing a hydrophobic layer have a A loose pore structure including nano-scale micropores and mesopores. Wherein, the pore diameter of the mesopore is larger than the pore diameter of the micropore. The pore structure in the amorphous activated carbon particles containing the hydrophobic layer can quickly absorb and release the air.

For the two-dimensional graphite layer and/or three-dimensional graphite microcrystalline structure contained in the amorphous activated carbon particle material containing the hydrophobic layer, it mainly affects the pore structure formed in the material. The more the content of the above two structures in the material, the more uniform the pore structure and the smaller the pore size of the pore structure after the material is processed through the carbonization process, so that the prepared sound-absorbing material can produce good resonant frequency reduction effect. There are a large number of irregular bonds on the edges of the two-dimensional graphite layer structure and the three-dimensional graphite crystallites. Irregular bonds can form tight connections between the two-dimensional graphite layer structure and the three-dimensional graphite crystallites, and interweave to form a pore structure. The valence electrons of carbon have sp2 hybrid orbitals and sp3 hybrid orbitals to form a hexagonal carbon network plane. The particles accumulated in this random form can form a dense and abundant pore structure. On the one hand, it is more conducive to the performance of the amorphous activated carbon particles containing the hydrophobic layer to absorb and release air. On the other hand, the structural uniformity and stability of the amorphous activated carbon particles containing the hydrophobic layer can be improved, and the structural strength of the amorphous activated carbon particles containing the hydrophobic layer can be improved.

Optionally, the amorphous activated carbon particles containing a hydrophobic layer may themselves have one or more of spherical, quasi-spherical, flake-shaped, and rod-shaped structures. Those skilled in the art can make adjustments flexibly according to the actual situation, and there is no limitation on this.

Regarding the pore structure including micropores and mesopores in the amorphous activated carbon particles containing the hydrophobic layer, the pore diameter of the micropores is 0.5-2 nm, and the pore diameter of the mesopores is 2-3.5 nm. The pore size of the micropores is limited to a smaller size, so that the formed particles can contain a sufficient and large number of micropores. On the one hand, it increases the overall cumulative pore volume of the particles, and on the other hand, it can increase the adsorption capacity of the particles to air molecules. A large number of small pores can absorb a large number of air molecules and improve the acoustic performance of the sound-absorbing material made. The pore size range of the mesopores is limited to the above range. The purpose is to provide sufficient flow space for the air molecules to allow the air molecules to move quickly when air molecules need to be quickly absorbed or released from the micropores. Reduce air clogging and micropores. On the other hand, if the pore size of the mesopores is too large, the cumulative pore volume of the particles will be reduced, and the ability of the particles to absorb air will decrease.

In the present invention, the cumulative pore volume of the amorphous activated carbon particles containing the hydrophobic layer ranges from 0.6 to ⁵ cm 3 /g. The cumulative pore volume of the amorphous activated carbon particles containing the hydrophobic layer will significantly affect the effect of the sound-absorbing material in reducing the resonance frequency.

The particle size, cumulative pore volume and specific surface area of amorphous activated carbon particles containing a hydrophobic layer are related. When the particle size is large, the particles are susceptible to uneven heating during the carbonization process, and the formed pore structure is imperfect. As a result, air molecules cannot enter and exit smoothly in the pore structure, and the cumulative pore volume becomes smaller, and the specific surface area is also reduced. Then it drops. When the particle size is too small, the particle strength is low and easily broken. When the cumulative pore volume is less than 0.6 cm ³ /g, the adsorption and desorption capacity of the amorphous activated carbon particles containing the hydrophobic layer for air molecules is significantly reduced. The low pore volume prevents air molecules from flowing in and out of the amorphous activated carbon particles containing the hydrophobic layer, and the particles cannot absorb a large amount of air molecules. When the cumulative pore volume increases to 0.6 cm ³ /g, the content of mesopores increases, so that the particles meet the need for rapid in and out of air molecules. The response speed of the adsorption and desorption of air molecules is obviously increased, and the equivalent expansion magnification of the rear acoustic cavity is significantly increased. After the cumulative pore volume continues to increase, the content of micropores increases correspondingly, and the amount of air molecules adsorbed by the particles also increases significantly. This can better reduce the resonant frequency.

In the amorphous activated carbon particles containing the hydrophobic layer, since the mesopores and the micropores are interpenetrated with each other, the two ensure the transmission, storage and convection of gas.

The inventor of the present invention has verified that filling the sound-absorbing material of the present invention into the rear acoustic cavity of the sound generating device can absorb and release air equivalent to expanding the volume of the rear acoustic cavity, which can expand the volume of the rear acoustic cavity. Times, where N>1. In the rear acoustic cavity of the sound generating device, the forced vibration of the sound-absorbing material will consume the energy of the sound wave. This effect is equivalent to an increase in the acoustic compliance of the air in the volume of the rear acoustic cavity, thereby reducing the resonance frequency.

The sound-absorbing material provided by the present invention can be applied to different types of sound-producing devices such as earphones, earpieces, speakers, sound boxes and the like. Putting the sound-absorbing material into the rear acoustic cavity of the sounding device virtually expands the volume of the rear acoustic cavity, which is also equivalent to increasing the damping of the sounding device, thereby reducing the resonance intensity. Finally, the resonance frequency of the sound emitting device can be reduced, and the effect of improving the acoustic performance of the sound emitting device can be achieved.

In addition, the sound-absorbing material provided by the present invention can repeatedly perform the adsorption and desorption of air molecules without performance degradation due to repeated adsorption and desorption of air molecules. That is, the sound-absorbing material provided by the present invention can be used repeatedly for a long time, has a long service life, and can save costs.

According to another embodiment of the present invention, a sound-absorbing material is provided. The sound-absorbing material is prepared according to the method for preparing the sound-absorbing material as described above.

The invention provides a sound absorbing material for reducing the resonance frequency of a sound emitting device. In order to reduce the resonant frequency of the sound emitting device to achieve better acoustic performance, the sound-absorbing material is usually filled in the rear acoustic cavity of the sound emitting device. In a specific example, the sound emitting device usually includes a front acoustic cavity and a rear acoustic cavity, and the sound-absorbing material is filled in the rear acoustic cavity of the sound device, specifically located in a special filling area. When the sound generating device is working, the sound-absorbing material in the form of loose accumulation will achieve the effect of adsorption and release of gas with the regular changes of the pressure in the rear acoustic cavity, so as to achieve the effect of increasing the volume of the rear acoustic cavity and reducing the resonance frequency.

According to another embodiment of the present invention, a sound generating device is provided. The sound generating device includes a housing, a vibrating component, and the above-mentioned sound-absorbing material. An accommodating cavity is formed inside the housing, and the vibration assembly is disposed in the housing. And, the sound-absorbing material is filled in the containing cavity.

Wherein, the vibration assembly divides the containing cavity into a front acoustic cavity and a rear acoustic cavity. The front acoustic cavity is communicated with the sound outlet on the housing, and the rear acoustic cavity is basically a closed space. The sound-absorbing material may be filled in the rear acoustic cavity. Of course, the present invention does not limit placing the sound-absorbing material in the rear acoustic cavity to adjust the sound and airflow of the rear acoustic cavity.

In addition, according to another embodiment of the present invention, an electronic device is also provided. The electronic equipment includes the sound emitting device as described above.

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

Claims (12)

1. The preparation method of the sound-absorbing material is characterized in that: the sound-absorbing material is prepared by mixing amorphous activated carbon particles containing a hydrophobic layer and a high molecular polymer binder;

   The amorphous activated carbon particles containing a hydrophobic layer include an activated carbon particle core and a hydrophobic layer coated on the outer surface of the activated carbon particle core; wherein the material of the hydrophobic layer is zeolite material, aerogel material, porous organic polymer Any one of the materials, the thickness of the hydrophobic layer is 0.1-10 μm;

   The amorphous activated carbon particles containing a hydrophobic layer have a loose pore structure inside, and the pore structure includes nano-scale micropores and mesopores;

   The particle size of the amorphous activated carbon particles containing the hydrophobic layer is 0.1-100 μm, and the particle size of the sound-absorbing material is 50-1000 μm.
2. The method for preparing a sound-absorbing material according to claim 1, wherein the particle size of the amorphous activated carbon particles containing the hydrophobic layer is 0.2-20 μm, and the particle size of the sound-absorbing material is 100-450 μm.
3. The method for preparing a sound-absorbing material according to claim 1, wherein the hydrophobic layer has a mass ratio of 1-50% by weight in the amorphous activated carbon particles containing the hydrophobic layer, and the core of the activated carbon particles is in the The mass ratio of the amorphous activated carbon particles containing the hydrophobic layer is 50-99 wt%.
4. The method for preparing a sound-absorbing material according to claim 1, wherein the activated carbon particle core material includes carbon element, hydrogen element and oxygen element;

   The activated carbon particle core material contains a chaotic layer structure formed by random accumulation of molecular fragments of two-dimensional graphite layers and/or three-dimensional graphite crystallites.
5. The method for preparing a sound-absorbing material according to claim 1, wherein the pore diameter of the micropores is 0.5-2 nm, and the pore diameter of the mesopores is 2-3.5 nm.
6. The method for preparing a sound-absorbing material according to claim 1, wherein the mass ratio of the high molecular polymer binder in the sound-absorbing material is 1-10 wt%.
7. The method for preparing a sound-absorbing material according to claim 1, wherein the high molecular polymer adhesive includes polyacrylic adhesive, polyvinyl alcohol adhesive, polystyrene adhesive, At least one of polyurethane-based adhesives, polyvinyl acetate-based adhesives, and polybutadiene rubber-based adhesives.
8. The method for preparing a sound-absorbing material according to claim 1, wherein the cumulative pore volume of the amorphous activated carbon particles containing the hydrophobic layer is 0.6-5 cm ³ /g.
9. The method for preparing a sound-absorbing material according to claim 1, wherein the bulk density of the sound-absorbing material is 0.05-0.8 g/cm ³ .
10. A sound-absorbing material, characterized in that the sound-absorbing material is prepared according to the method for preparing a sound-absorbing material according to any one of claims 1-9.
11. A sounding device, which is characterized in that it comprises:

    A housing in which a containing cavity is formed;

    A vibration component, the vibration component is arranged in the housing;

    The accommodating cavity is provided with the sound-absorbing material according to any one of claims 1-10.
12. An electronic device, characterized in that it comprises the sound emitting device according to claim 11.