Porous sound-absorbing filling particles as well as preparation and application methods thereof

Abstract

The invention relates to the technical field of loudspeakers, in particular to a porous sound-absorbing filling particle and a preparation and application method thereof, the porous sound-absorbing filling particle is a microsphere-shaped particle which is formed by gradually enlarging material powder in an adhesive vaporific environment and is provided with multilevel channels, and the particle size of the porous sound-absorbing filling particle is 40-80 meshes; the material powder is prepared by mixing an MFI type molecular sieve, chopped glass fibers and mica powder according to a mass ratio of 20: 1: 1; the adhesive is a mixed aqueous solution comprising a binder and a thickening agent, the mass ratio of the binder to the thickening agent is 50: 1, and in the mixed aqueous solution, the concentration of the thickening agent is 0.05%-0.1%; the mixing ratio of the material powder to the adhesive is 1: 0.05. According to the preparation method, the powder material is directly combined with the adhesive, and the layer-by-layer forming of particles is realized by utilizing the atomizing and spraying characteristics of the adhesive and the self-aggregation characteristics of the material powder, so that the step of preparing a parent nucleus is omitted, the production process is greatly simplified, and the production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of loudspeakers, and in particular to porous sound-absorbing filling particles and a preparation and application method thereof. Background Art

[0002] Porous sound-absorbing filling materials are widely used in the resonance cavity of loudspeakers to virtually increase the volume of the resonance space of the rear cavity of the loudspeaker and reduce the resonance frequency of the low-frequency sound waves of the loudspeaker. At present, porous sound-absorbing filling materials are mainly prepared from zeolite molecular sieves and binders. Their combination has a very important influence on the porosity, sphericity, strength and sound absorption performance of the microsphere particles. In loudspeaker applications, for the sake of quantification and process filling feasibility, the above powdered sound-absorbing materials must first be prepared into particles with a particle size of 0.10-10mm. According to the size and structure of the rear sound cavity of the loudspeaker product, the particle size is selected to float in a smaller range within 0.10-10mm.

[0003] Porous sound-absorbing filling materials are usually in the form of microsphere particles, which are conducive to the incidence and dissipation of sound waves from all angles. The particles obtained by the existing granulation methods have low sphericity. The main reason is that the surface area of ​​the molecular sieve powder in the field is too large and it is easy to agglomerate. When the binder is sprayed, it is easy to cause a large number of particles to agglomerate instead of growing layer by layer. In addition, the traditional drying method is not conducive to the formation of a loose porous structure. Therefore, it is difficult to prepare porous low-frequency sound-absorbing filling microspheres by traditional granulation methods.

[0004] Chinese patent CN112876277A discloses an acoustic enhancement material block, which requires uniform mixing of porous raw materials, binders, fillers, water, etc., freeze drying to obtain a porous block sample, and then cutting and granulating the porous block material into small particle samples. The preparation process is complicated, including multiple steps such as mixing, freeze drying, and granulation. Another patent CN108377456B discloses a sound-absorbing microsphere material, which requires preliminary granulation of zeolite particles and binders to obtain a mother core, and then secondary granulation through a centrifugal coating granulator. The preparation process is complicated. The sound-absorbing material disclosed in patent CN111204770B for improving the low-frequency response of a speaker includes additional steps such as precipitation, filtration, and washing in addition to mixing, drying, and granulation. Although it is beneficial to improve the performance of the porous material, the preparation process is too complicated. The highly porous coating disclosed in patent CN112866881A eliminates the need for drying and granulation, and directly sprays the mixed porous raw materials, adhesives, fillers, water, etc., on the back cavity surface behind the speaker. However, the coating thickness is limited, and the effect of reducing the resonant frequency of the speaker is also limited.

[0005] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art known to those skilled in the art. Summary of the invention

[0006] The technical problem to be solved by the present invention is: to provide porous sound-absorbing filling particles, and to provide a preparation method and an application method of the porous sound-absorbing filling particles, wherein a specific type of binder and specific steps are used in coordination with each other, especially spray granulation pretreatment can improve the fluidity of the powder, and the collision between particles can be increased during the granulation process; a specific type and concentration of binder can be used to improve the plasticity and bonding force of the powder, and the powder is wrapped layer by layer on the surface of the blank ball and grows slowly, thereby reducing the stacking density; and the porous low-frequency sound-absorbing filling microspheres can be successfully prepared in batches, and then used in speakers, which is beneficial to low-frequency sound absorption.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A porous sound-absorbing filling particle, the porous sound-absorbing filling particle is a micro-spherical particle with multi-level pores formed by the material powder gradually growing in the adhesive mist environment, the multi-level pores refer to the microporous structure of the material powder itself, and the pores formed between multiple material powders in the formed micro-spherical particles, the particle size of the porous sound-absorbing filling particle is 40 to 80 meshes;

[0009] Furthermore, the binder is polyacrylate or povidone; and the thickener is sodium polymethacrylate.

[0010] The material powder is prepared by mixing MFI molecular sieve, short glass fiber and mica powder in a mass ratio of 20:1:1; the adhesive is a mixed aqueous solution including a binder and a thickener, the mass ratio of the binder and the thickener is 50:1, and the concentration of the thickener in the mixed aqueous solution is 0.05% to 0.1%; it can ensure that the particles have appropriate viscosity during the molding process, so that they can form a stable spherical structure without affecting the formation of the pore structure. The mixing ratio of the material powder and the adhesive is 1:0.05. Among them, the MFI molecular sieve mainly provides a porous sound-absorbing structure, and the short glass fiber increases the strength and stability of the particles. On this basis, the glass fiber can be surface-modified to enhance the bonding strength between the fiber and the adhesive, thereby improving the durability and sound absorption efficiency of the overall material. Mica powder improves the physical properties of the particles, especially heat resistance and chemical stability. The polyacrylate or polyvidone in the adhesive plays a bonding role, and the thickener sodium polymethacrylate helps to control the molding process of the particles so that they maintain a good porous structure.

[0011] A method for preparing porous sound-absorbing filling particles comprises the following steps:

[0012] S1: MFI molecular sieve, chopped glass fiber and mica powder are mixed evenly to obtain material powder;

[0013] S2 dissolves the binder and thickener into water, mixes them thoroughly to obtain an adhesive, and puts the material powder into a granulator to combine with the adhesive sprayed in mist, so that the material powder gradually becomes larger to form full microsphere particles;

[0014] In this step, the balance between adhesion and fluidity is crucial to the smooth formation of particles. During the granulation process, when the adhesive concentration is moderate, the adhesion between the powder particles is moderate, so that the particles can be gathered layer by layer during collision and rolling to form uniform microsphere particles; moderate fluidity can ensure that the powder particles can flow and roll freely in the environment of spray adhesive, which helps to form small and uniform particles. Therefore, controlling the adhesive concentration within the concentration range of 0.05% to 0.1% can effectively balance adhesion and fluidity.

[0015] The present invention can help achieve uniformity of particles by finding the optimal adhesive concentration through repeated trials, as shown below:

[0016] (1) Aggregation into spheres layer by layer: During the forming process, since the adhesive can form a thin layer coating on the surface of the particles, the particles are continuously wrapped by the powder layer during the rolling process, and are aggregated into spheres layer by layer. This layer-by-layer forming mechanism makes the particle surface smoother and more uniform, which helps to control the pore size distribution on the surface and improve the performance of the sound-absorbing particles.

[0017] (2) Experimental optimization to avoid agglomeration: In the experiment, the stirring speed, spraying time and spraying pressure were adjusted to further cooperate with the effect of the adhesive to reduce the agglomeration tendency of the particles; especially in the low concentration range of the adhesive (0.05%), by increasing the stirring rate and extending the spraying time, the particles were coated with powder layer by layer during the forming process, reducing the adhesion between the particles, thereby forming independent microspherical particles.

[0018] (3) Testing and feedback on uniformity: After each experiment, the particle size distribution is statistically analyzed to test its uniformity. If the particle size distribution is too wide, it may indicate that the adhesive concentration or spray parameters need to be further adjusted; specifically, image analysis software or screening methods are used to accurately measure the size distribution and shape of the particles to determine their uniformity. The more uniform the particles are, the closer the adhesive concentration and granulation conditions are to the optimal state.

[0019] S3 dries and sieves the wet particles obtained in S2 to obtain porous sound-absorbing filling particles.

[0020] Furthermore, in step S1, the MFI molecular sieve, chopped glass fibers and mica powder are placed in a sealed container and mixed with an air flow at a rate of 2 to 4 m / s for more than 10 minutes to achieve uniform mixing.

[0021] Among them, when the granulator is a centrifugal granulator, in step S2, the material powder is put into the granulator and combined with the adhesive sprayed in mist, so that the material powder gradually becomes larger to form full microsphere particles, which specifically refers to:

[0022] S21 puts the material powder mixed in S1 into the centrifugal granulator, so that the bottom disc of the centrifugal granulator starts to rotate;

[0023] S22: Dissolve the binder and thickener in water and mix thoroughly, then spray them into the centrifugal granulator in mist form. Adjust the atomization pressure at the spray gun to 0.5-0.6MPa and the spray frequency to 25-35Hz, so that the material powder rolls and gradually becomes larger to form full microsphere particles, and collect 40-80 mesh wet particles.

[0024] During the granulation process, the bottom disc of the centrifugal granulator rotates, providing a dynamic rolling environment for the material powder. It promotes the full contact and mixing between the material powders, increases the contact area between the material powders and the mist adhesive, and thus improves the granulation efficiency. By adjusting the spray pressure and the atomized particle size, the pore size on the particle surface can be effectively controlled. Higher spray pressure can make the adhesive form smaller droplets, which can form smaller pores and is conducive to forming more delicate surface channels. Conversely, appropriately reducing the pressure can increase the diameter of the droplets, thereby forming a larger pore size.

[0025] Furthermore, in step S3, wet particles of 40 to 80 meshes are collected, and the obtained wet particles are placed in a refrigerator at -80°C for 12 hours, and then taken out and quickly placed in a freeze dryer for freeze drying for 5 hours, thereby obtaining porous sound-absorbing filling particles.

[0026] Centrifugal granulation is different from centrifugal coating granulation. It mainly relies on centrifugal force to form particles, does not involve the coating process, and is difficult to form annular air. Its working principle is mainly to use the high-speed rotation of the bottom turntable to generate a strong centrifugal force, so that the material rolls on the disc under the action of centrifugal force. At this time, the liquid inlet and atomization system sprays the liquid such as the adhesive evenly onto the disc. The raw material powder gradually rolls and adheres under the action of the adhesive. The powder is wrapped layer by layer on the surface of the blank ball and slowly grows to form spherical particles. The stacking density, porosity and sphericity of the particles can be adjusted by controlling the rotation speed and spraying amount, and finally the porosity of the particles is increased by freeze drying.

[0027] The present invention obtains porous low-frequency sound-absorbing filling microsphere particles with extremely high sphericity through centrifugal granulation, which overcomes the problem that small particles of traditional centrifugal granulation are easy to agglomerate and difficult to form into balls, avoids the collapse of internal pores caused by direct drying of microsphere particles, resulting in a decrease in porosity, and utilizes freeze drying to easily form a porous loose particle structure, which is beneficial to sound absorption.

[0028] When the granulator is a boiling granulator, in step S2, the material powder is put into the granulator and combined with the adhesive sprayed in mist, so that the material powder gradually becomes larger to form full microsphere particles, which specifically refers to:

[0029] S21 puts the mixed particles into the boiling granulator, blows hot air with a temperature of 120-130°C at the bottom of the boiling granulator at a speed of 1-2m / s, blows the particles up to form a solid bridge, strengthens the bonding force between the particles, makes the particle structure more stable and not easy to break;

[0030] S22: Dissolve the binder and thickener in water and mix thoroughly, then spray them into the boiling granulator in the form of mist, adjust the atomization pressure at the spray gun to 0.5-0.6MPa and the spray frequency to 25-35Hz, so that the material powder is agglomerated into particle nuclei, which gradually become larger to form full microsphere particles;

[0031] Furthermore, in step S3, synchronous drying is performed, and under the action of hot air, the water evaporates continuously, so that the liquid bridges between the powders are transformed into solid bridges, and 40-80 mesh porous sound-absorbing filling particles are obtained by screening. The hot air not only has a drying effect, but also promotes the transformation of the liquid bridges between the powders into solid bridges, so that the particles are solidified while being formed. This synchronous drying and curing process greatly shortens the production cycle and improves production efficiency.

[0032] It can be seen that the present invention uses a boiling one-step granulation method at this time, so that the traditional mixing, granulation and drying processes are completed at one time in the same closed container, which greatly simplifies the preparation process, and reduces the process and cost while improving production efficiency and maintaining stable product quality. The working principle of fluidized bed granulation is mainly that the purified air is heated and then enters the container through a sieve plate, and then hot materials are added to make it fluid. At this time, the adhesive is sprayed in a mist form, so that the material powder can be agglomerated into particle nuclei, which can gradually become larger to form full particles. Then synchronous drying is required. At this time, the liquid bridges between the powders will be converted into solid bridges, so that porous, soft particles with a large surface area can be obtained.

[0033] The application of porous sound-absorbing filling particles in electronic devices specifically includes an electronic device, in which the speaker resonance cavity of the electronic device is filled with the porous sound-absorbing filling particles.

[0034] The beneficial effects of the present invention are:

[0035] (1) Traditional processes often require the pre-preparation of a core material (mother core), and then other materials are coated around the mother core to form composite particles. Such steps increase the complexity and time cost of the process. The present invention directly combines the powder material with the adhesive, utilizes the atomization spraying of the adhesive and the self-aggregation characteristics of the material powder, realizes the layer-by-layer forming of the particles, eliminates the step of preparing the mother core, greatly simplifies the production process, and improves production efficiency. Due to the lack of the restriction of the mother core, the powder material can self-aggregate more freely under the action of the adhesive to form a more uniform particle structure. This self-aggregation method can ensure that materials such as molecular sieves, glass fibers and mica powder are evenly distributed throughout the particles, there is no material segregation problem of the core-shell structure, and the particles will automatically roll round under the action of centrifugal force to better form a sphere. In the process of layer-by-layer forming of the particles, the multi-level channels inside the particles can be naturally formed as the adhesive is sprayed layer by layer, which helps to optimize the porosity and sound absorption performance of the particles, especially the absorption of low-frequency sound waves.

[0036] (2) The preparation method of the present invention has strong adaptability, and the ratio of powder material and adhesive, the spray fineness of the adhesive and the process parameters of the granulator can be flexibly adjusted. The particle size, porosity and structure of the particles can be regulated according to different sound absorption requirements, especially for low-frequency sound waves, to ensure the adjustability of material properties. The design without the need for a parent core not only simplifies the process, but also reduces raw materials and energy consumption. The present invention directly utilizes the interaction between powder and adhesive to generate target particles more economically and efficiently, thereby reducing production costs. In addition, due to the simplification of the process flow, the maintenance and operation of the equipment are also more convenient, further reducing the operation and maintenance costs of the equipment. The porous particles prepared by the present invention are uniformly filled with particles, which is convenient for screening finished products and secondary recycling of waste materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 This is a microscope image of the porous sound-absorbing filling particles in Example 1 of the present invention;

[0039] Figure 2 This is a SEM image of the porous sound-absorbing filling particles in Example 1 of the present invention;

[0040] Figure 3This is the frequency response curve of the porous sound-absorbing filling particles in Example 2 of the present invention. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0042] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0044]

[0045]

[0046] Example 1

[0047] like Figure 1 and Figure 2 A porous sound-absorbing filling particle is shown, the porous sound-absorbing filling particle is a micro-spherical particle with multi-level pores formed by the material powder gradually growing in the adhesive mist environment, and the particle size of the porous sound-absorbing filling particle is 40 to 80 meshes;

[0048] The material powder is prepared by mixing MFI molecular sieve, short glass fiber and mica powder in a mass ratio of 20:1:1; the adhesive is a mixed aqueous solution including polyvidone and sodium polymethacrylate, the mass ratio of the binder to the thickener is 50:1, and the concentration of the thickener in the mixed aqueous solution is 0.05% to 0.1%; the mixing ratio of the material powder and the adhesive is 1:0.05.

[0049] A method for preparing porous sound-absorbing filling particles comprises the following steps:

[0050] S1: 300g of MFI molecular sieve, 15g of chopped glass fiber and 15g of mica powder are placed in a sealed container, and mixed at a rate of 2-4m / s for more than 10min to achieve uniform mixing to obtain material powder;

[0051] S2: Put the mixed material powder in S1 into the centrifugal granulator, so that the bottom disc of the centrifugal granulator starts to rotate; dissolve 15g of povidone as a binder and 0.3g of sodium polymethacrylate in 300g of water, mix them thoroughly, and spray them into the centrifugal granulator in a mist form, adjust the atomization pressure at the spray gun to 0.5MPa and the spray frequency to 30Hz, so that the material powder rolls and gradually becomes larger to form full microsphere particles;

[0052] S3 collects wet particles of 40 to 80 meshes, puts the obtained wet particles into a refrigerator at -80°C and freezes them for 12 hours, then takes them out and quickly puts them into a freeze dryer and freeze-dries them for 5 hours, thereby obtaining porous sound-absorbing filling particles.

[0053] Example 2

[0054] A porous sound-absorbing filling particle, the porous sound-absorbing filling particle is a micro-spherical particle with multi-level pores formed by the gradual enlargement of material powder in an adhesive mist environment, and the particle size of the porous sound-absorbing filling particle is 40 to 80 meshes;

[0055] The material powder is prepared by mixing MFI molecular sieve, short glass fiber and mica powder in a mass ratio of 20:1:1; the adhesive is a mixed aqueous solution including polyacrylate and sodium polymethacrylate, the mass ratio of the binder to the thickener is 50:1, and the concentration of the thickener in the mixed aqueous solution is 0.05% to 0.1%; the mixing ratio of the material powder and the adhesive is 1:0.05.

[0056] A method for preparing porous sound-absorbing filling particles comprises the following steps:

[0057] S1: 5 kg of MFI molecular sieve, 250 g of chopped glass fiber and 250 g of mica powder are placed in a sealed container and mixed at a rate of 2 to 4 m / s for more than 10 minutes to achieve uniform mixing and obtain material powder;

[0058] S2: Put the mixed particles into a boiling granulator, blow hot air at a temperature of 120-130°C at the bottom of the boiling granulator at a speed of 1-2 m / s to blow up the particles to form a solid bridge; dissolve 250g of polyacrylate as a binder and 5g of sodium polymethacrylate in water and mix them thoroughly, then spray them into the boiling granulator in a mist form, adjust the atomization pressure at the spray gun to 0.5-0.6MPa and the spray frequency to 25-35Hz, so that the material powder is agglomerated into particle nuclei, which gradually become larger to form full microsphere particles;

[0059] S3 synchronous drying, under the action of hot air, the water evaporates continuously, so that the liquid bridges between the powders are transformed into solid bridges, and 40-80 mesh porous sound-absorbing filling particles are obtained by screening.

[0060] Comparative Example 1

[0061] A porous sound-absorbing filling particle, the porous sound-absorbing filling particle is a micro-spherical particle with multi-level pores formed by the gradual enlargement of material powder in an adhesive mist environment, and the particle size of the porous sound-absorbing filling particle is 20 meshes;

[0062] The material powder is prepared by mixing MFI molecular sieve, short glass fiber and mica powder in a mass ratio of 20:1:1; the adhesive is a mixed aqueous solution including polyvidone and sodium polymethacrylate, the mass ratio of the binder to the thickener is 50:1, and the concentration of the thickener in the mixed aqueous solution is 0.05% to 0.1%; the mixing ratio of the material powder and the adhesive is 1:0.05.

[0063] A method for preparing porous sound-absorbing filling particles comprises the following steps:

[0064] S1: 300g of MFI molecular sieve, 15g of chopped glass fiber and 15g of mica powder are placed in a sealed container, and mixed at a rate of 2-4m / s for more than 10min to achieve uniform mixing to obtain material powder;

[0065] S2: Put the mixed material powder in S1 into the centrifugal granulator, so that the bottom disc of the centrifugal granulator starts to rotate; dissolve 15g of povidone as a binder and 0.3g of sodium polymethacrylate in 300g of water, mix them thoroughly, and spray them into the centrifugal granulator in a mist form, adjust the atomization pressure at the spray gun to 0.5MPa and the spray frequency to 30Hz, so that the material powder rolls and gradually becomes larger to form full microsphere particles;

[0066] S3 collects wet particles of 40 to 80 meshes, puts the obtained wet particles into a refrigerator at -80°C and freezes them for 12 hours, then takes them out and quickly puts them into a freeze dryer and freeze-dries them for 5 hours, thereby obtaining porous sound-absorbing filling particles.

[0067] Comparative Example 2

[0068] A porous sound-absorbing filling particle, the porous sound-absorbing filling particle is a micro-spherical particle with multi-level pores formed by the gradual enlargement of material powder in an adhesive mist environment, and the particle size of the porous sound-absorbing filling particle is 20 meshes;

[0069] The material powder is prepared by mixing MFI molecular sieve, short glass fiber and mica powder in a mass ratio of 20:1:1; the adhesive is a mixed aqueous solution including polyacrylate and sodium polymethacrylate, the mass ratio of the binder to the thickener is 50:1, and the concentration of the thickener in the mixed aqueous solution is 0.05% to 0.1%; the mixing ratio of the material powder and the adhesive is 1:0.05.

[0070] A method for preparing porous sound-absorbing filling particles comprises the following steps:

[0071] S1: 5 kg of MFI molecular sieve, 250 g of chopped glass fiber and 250 g of mica powder are placed in a sealed container and mixed at a rate of 2 to 4 m / s for more than 10 minutes to achieve uniform mixing and obtain material powder;

[0072] S2: Put the mixed particles into a boiling granulator, blow hot air at a temperature of 120-130°C at the bottom of the boiling granulator at a speed of 1-2 m / s to blow up the particles to form a solid bridge; dissolve 250g of polyacrylate as a binder and 5g of sodium polymethacrylate in water and mix them thoroughly, then spray them into the boiling granulator in a mist form, adjust the atomization pressure at the spray gun to 0.5-0.6MPa and the spray frequency to 25-35Hz, so that the material powder is agglomerated into particle nuclei, which gradually become larger to form full microsphere particles;

[0073] S3 synchronous drying, under the action of hot air, the water evaporates continuously, so that the liquid bridges between the powders are transformed into solid bridges, and 40-80 mesh porous sound-absorbing filling particles are obtained by screening.

[0074] Performance test: To measure the impedance frequency curve, first fill all the filling particles into the rear cavity (1.1mL) of the micro speaker, then close the back cover and tighten it to seal it. Then, use two wires to connect the measurement system to the micro speaker equipment, obtain the impedance-frequency curve through the test software, and finally calculate the resonant frequency shift (△f0).

[0075] Compared with traditional methods, this method has rich and diverse pore structures, larger specific surface area, and better roundness, which accelerates the diffusion of gas in the pores, is beneficial to the reflection and dissipation of sound waves, thereby significantly increasing the resonant frequency offset and improving the low-frequency acoustic performance of the speaker.

[0076] like Figure 3 As shown in the figure, the impedance-frequency response curve of the sound-absorbing material obtained by granulation, drying and sieving with molecular sieve as raw material and the relationship between the particle size. From the figure, it can be seen that the multi-level pore filling particles after molding with 40-80 mesh have better performance test results.

[0077] Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. A porous sound-absorbing filling particle, characterized in that: The porous sound-absorbing filling particles are micro-spherical particles with multi-level pores formed by the material powder gradually growing in the adhesive mist environment, and the particle size of the porous sound-absorbing filling particles is 40-80 meshes; The material powder is prepared by mixing MFI molecular sieve, chopped glass fiber and mica powder in a mass ratio of 20:1:1; the adhesive is a mixed aqueous solution including a binder and a thickener, the mass ratio of the binder to the thickener is 50:1, and the concentration of the thickener in the mixed aqueous solution is 0.05% to 0.1%; the mixing ratio of the material powder and the adhesive is 1:0.

05.

2. The porous sound-absorbing filling particle according to claim 1, characterized in that: The binder is polyacrylate or povidone; the thickener is sodium polymethacrylate.

3. A method for preparing porous sound-absorbing filling particles according to claim 1 or 2, characterized in that: The steps are as follows: S1: MFI molecular sieve, chopped glass fiber and mica powder are mixed evenly to obtain material powder; S2: dissolving the binder and thickener into water, mixing them thoroughly to obtain an adhesive, and putting the material powder into a granulator to combine with the adhesive sprayed in mist, so that the material powder gradually becomes larger to form full microsphere particles; S3, drying and sieving the wet particles obtained in S2 to obtain porous sound-absorbing filling particles.

4. The method for preparing porous sound-absorbing filling particles according to claim 3, characterized in that: In step S1, the MFI molecular sieve, chopped glass fiber and mica powder are placed in a sealed container and mixed with an air flow at a rate of 2-4 m / s for more than 10 minutes to achieve uniform mixing.

5. The method for preparing porous sound-absorbing filling particles according to claim 3, characterized in that: In step S2, the material powder is put into a granulator and combined with the adhesive sprayed in mist, so that the material powder gradually becomes larger to form full microsphere particles, including: S21: putting the material powder mixed in S1 into the centrifugal granulator, so that the bottom disc of the centrifugal granulator starts to rotate; S22: After the binder and thickener are dissolved in water and fully mixed, they are sprayed into the centrifugal granulator in a mist form, and the atomization pressure and spray frequency at the spray gun are adjusted to make the material powder roll and gradually grow larger to form full microsphere particles.

6. The method for preparing porous sound-absorbing filling particles according to claim 5, characterized in that: In step S3, wet particles of 40-80 meshes are collected, and the obtained wet particles are placed in a refrigerator at -80°C for 12 hours, and then taken out and quickly placed in a freeze dryer for freeze drying for 5 hours, thereby obtaining porous sound-absorbing filling particles.

7. The method for preparing porous sound-absorbing filling particles according to claim 3, characterized in that: In step S2, the material powder is put into a granulator and combined with the adhesive sprayed in mist, so that the material powder gradually becomes larger to form full microsphere particles, including: S21: putting the mixed particles into a boiling granulator, blowing hot air at a temperature of 120-130° C. at a speed of 1-2 m / s into the bottom of the boiling granulator to blow up the particles to form a solid bridge; S22: After the binder and thickener are dissolved in water and fully mixed, they are sprayed into the boiling granulator in a mist form, and the atomization pressure and spray frequency at the spray gun are adjusted to make the material powder agglomerate into particle nuclei, which gradually become larger to form full microsphere particles.

8. The method for preparing porous sound-absorbing filling particles according to claim 7, characterized in that: In step S3, simultaneous drying is performed, and under the action of hot air, the water evaporates continuously, so that the liquid bridges between the powders are transformed into solid bridges, and 40-80 mesh porous sound-absorbing filling particles are screened.

9. Use of the porous sound-absorbing filling particles according to claim 1 or 2 in electronic equipment.

10. An electronic device, characterized in that: The speaker resonance cavity of the electronic device is filled with the porous sound-absorbing filling particles according to claim 1 or 2.

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