A sound-absorbing microsphere material, its preparation method, a loudspeaker, and an electronic device

Abstract

The present invention provides a sound-absorbing microsphere material, a preparation method thereof, a loudspeaker, and an electronic device. The preparation method includes: mixing a silicon source, an aluminum source, an alkali, an organic template agent, a first carbon nanotube pore-forming agent, and water to form a gel, and then performing primary crystallization on the gel to obtain a zeolite primary crystal grain slurry; mixing the zeolite primary crystal grain slurry, the silicon source, the aluminum source, the organic template agent, and a second carbon nanotube pore-forming agent uniformly and granulating to obtain particles; mixing the particles with water and performing secondary crystallization, and then successively washing, drying, and calcining the secondary crystallization product to obtain ZSM-5 microspheres; mixing a metal salt solution with the ZSM-5 microspheres and performing an ion exchange and sodium removal reaction, and then successively washing and drying the product to obtain the sound-absorbing microsphere material. The sound-absorbing microsphere material provided by the present invention can better adjust the compliance of the air in the rear cavity of the loudspeaker in the rear cavity of the loudspeaker, thereby achieving a better low-frequency improvement effect.

Description

Technical Field

[0001] The present invention relates to a sound-absorbing microsphere material, a preparation method thereof, a loudspeaker, and an electronic device, belonging to the technical field of materials, especially the technical field of electroacoustic materials. Background Art

[0002] With the development of multimedia devices, micro loudspeakers are widely used. However, due to space limitations, it is difficult to improve the performance of micro loudspeakers in the low-frequency range. In a loudspeaker system, at present, molecular sieve sound-absorbing particles are mainly used to improve its low-frequency performance, and the molecular sieve sound-absorbing particles are mainly obtained by bonding and molding multiple molecular sieve microparticles through a binder.

[0003] The molecular sieve sound-absorbing particles mainly improve the low-frequency performance through their porous structure in the micro loudspeaker, but the binder will enter the molecular sieve pores or cover on its surface, blocking the pores, reducing the specific surface area and porosity. At the same time, the direct stacking of molecular sieve microparticles together to form particles will cause a shielding effect between the microparticles, and there is a disadvantage that some regions / pores cannot play a role. Moreover, the stacking between molecular sieve microparticles will also reduce the specific surface area of the molecular sieve sound-absorbing particles. These situations will ultimately reduce the improvement of the low-frequency effect of the loudspeaker. Therefore, there is an urgent need in the art for a method to fully exert the low-frequency improvement effect of the sound-absorbing particles during the forming process.

[0004] Therefore, providing a new type of sound-absorbing microsphere material, a preparation method thereof, a loudspeaker, and an electronic device has become an urgent technical problem to be solved in the art. Summary of the Invention

[0005] In order to solve the above-mentioned disadvantages and deficiencies, an object of the present invention is to provide a preparation method of a sound-absorbing microsphere material.

[0006] Another object of the present invention is also to provide a sound-absorbing microsphere material, which is prepared by the above-mentioned preparation method of the sound-absorbing microsphere material.

[0007] Still another object of the present invention is also to provide a loudspeaker, in which the above-mentioned sound-absorbing microsphere material is assembled in the rear cavity of the loudspeaker.

[0008] Yet another object of the present invention is also to provide an electronic device, in which the above-mentioned sound-absorbing microsphere material is assembled in the rear cavity of the loudspeaker.

[0009] In order to achieve the above objects, on the one hand, the present invention provides a preparation method of a sound-absorbing microsphere material, wherein the preparation method includes:

[0010] Step 1: Mix a silicon source, an aluminum source, an alkali, an organic template agent, a first carbon nanotube pore-forming agent, and water in a weight ratio of 1:0.01033 - 0.0413:0.1 - 0.15:0.32 - 0.46:0.0001 - 0.0024:1.95 to form a gel, and then subject the gel to primary crystallization to obtain a zeolite primary crystal slurry;

[0011] Step 2: Mix the zeolite primary crystal slurry, the silicon source, the aluminum source, the organic template agent, and a second carbon nanotube pore-forming agent in a weight ratio of 1:0.02 - 0.05:0.000035:0.0004 - 0.001:0.0015 - 0.003, mix evenly, and then granulate to obtain particles;

[0012] Step 3: Mix the particles with water and perform secondary crystallization, and then successively wash, dry, and calcine the secondary crystallization product to obtain ZSM-5 microspheres;

[0013] Step 4: Mix a metal salt solution with the ZSM-5 microspheres to carry out an ion exchange and sodium removal reaction, and then successively wash and dry the product to obtain the sound-absorbing microsphere material.

[0014] As a specific embodiment of the above preparation method of the present invention, the silicon source includes one or a combination of several of silica sol, sodium silicate, tetraethyl orthosilicate, etc.;

[0015] The aluminum source includes one or a combination of several of aluminum nitrate nonahydrate, sodium metaaluminate, aluminum sulfate, triethylaluminum, etc.;

[0016] The organic template agent includes tetrapropylammonium hydroxide and / or tetrapropylammonium bromide, etc.;

[0017] The alkali includes sodium hydroxide and / or potassium hydroxide, etc.

[0018] As a specific embodiment of the above preparation method of the present invention, the silicon source is silica sol.

[0019] As a specific embodiment of the above preparation method of the present invention, in Step 1, the silicon source is silica sol.

[0020] As a specific embodiment of the above preparation method of the present invention, the aluminum source is aluminum nitrate nonahydrate.

[0021] As a specific embodiment of the above preparation method of the present invention, the organic template agent is tetrapropylammonium hydroxide.

[0022] As a specific embodiment of the above-described preparation method of the present invention, wherein the length of the second carbon nanotube pore former is greater than the length of the first carbon nanotube pore former. In the present invention, the length of the second carbon nanotube pore former being greater than the length of the first carbon nanotube pore former can enable the second carbon nanotube pore former to form more micropores (i.e., the micropores of the carbon nanotubes themselves) by interpenetrating in the sound-absorbing microsphere material, and form longer mesoporous channels (the hollow mesoporous channels inherent in the carbon nanotubes), which is more conducive to the transmission of gas inside the sound-absorbing microsphere material.

[0023] As a specific embodiment of the above-described preparation method of the present invention, wherein the length of the first carbon nanotube pore former is 0.1 - 1 μm, and the length of the second carbon nanotube pore former is 5 - 100 μm.

[0024] As a specific embodiment of the above-described preparation method of the present invention, wherein the diameter ranges of the first carbon nanotube pore former and the second carbon nanotube pore former are respectively 5 - 15 nm.

[0025] In the present invention, two carbon nanotube pore formers (especially multi-walled carbon nanotubes) with different lengths are used as structure-directing agents during the primary crystallization and secondary crystallization processes, and the length of the carbon nanotube pore former used in the secondary crystallization process is greater than the length of the carbon nanotube pore former used in the primary crystallization process. Thus, different levels of pore channels can be formed in the molecular sieve particles and the sound-absorbing microsphere material structure, enabling the sound-absorbing microsphere material to better adjust the compliance of the air in the speaker rear cavity in the speaker rear cavity, and thus exerting a better low-frequency improvement effect. That is, by adding carbon nanotubes with different lengths to the molecular sieve particles and the sound-absorbing microsphere material respectively and ensuring that the carbon nanotubes are not removed during the calcination process, the micropore volume and mesopore volume of the sound-absorbing microsphere material are increased, thereby improving its gas adsorption and desorption efficiency and improving the low-frequency improvement effect.

[0026] As a specific embodiment of the above-described preparation method of the present invention, wherein both the first carbon nanotube pore former and the second carbon nanotube pore former are multi-walled carbon nanotubes.

[0027] As a specific embodiment of the above-described preparation method of the present invention, wherein in step one, the gel is aged before primary crystallization. The present invention does not make specific requirements on the aging temperature, time, etc., and can be reasonably adjusted according to the actual on-site operation needs. In some embodiments of the present invention, the aging can be aging at room temperature for 4 h.

[0028] As a specific embodiment of the above-described preparation method of the present invention, wherein in step one, the primary crystallization is crystallization at 150 - 200 °C for 10 - 20 h.

[0029] In the first step of the preparation method provided by the present invention described above, the zeolite primary crystal slurry contains zeolite primary crystals, unreacted silicon source, alkali, water, etc.

[0030] As a specific embodiment of the preparation method described above of the present invention, in the first step, the particle size of the zeolite primary crystals in the zeolite primary crystal slurry is 0.3 - 5 μm.

[0031] The present invention does not make specific requirements on the granulation method used in the second step, and a suitable granulation method can be selected according to the actual on-site operation needs. In some embodiments of the present invention, the granulation can be, for example, spray granulation.

[0032] As a specific embodiment of the preparation method described above of the present invention, in the second step, the size of the particles is 0.1 - 0.5 mm.

[0033] As a specific embodiment of the preparation method described above of the present invention, in the second step, the silicon-to-aluminum mass ratio in the secondary crystallization process is higher than that in the primary crystallization process. The obtained sound-absorbing microsphere material has better hydrophobicity.

[0034] In the first and second steps of the present invention, the dosage of the silicon source is based on the weight of the solid component therein.

[0035] As a specific embodiment of the preparation method described above of the present invention, in the third step, the particles and water are mixed at a mass ratio of 10:1.5 - 4.

[0036] As a specific embodiment of the preparation method described above of the present invention, in the third step, the secondary crystallization is carried out at 100 - 180 °C for 20 - 100 h.

[0037] As a specific embodiment of the preparation method described above of the present invention, in the third step, the calcination is carried out in an inert atmosphere, the calcination temperature is 400 - 600 °C, and the calcination time is 4 - 8 h. In the third step, the purpose of the calcination is to remove unreacted substances and organic template agents, rather than removing carbon nanotubes.

[0038] As a specific embodiment of the preparation method described above of the present invention, in the third step, the density of the ZSM-5 microspheres is 0.45 - 0.8 g / mL.

[0039] As a specific embodiment of the preparation method described above of the present invention, in the fourth step, the weight ratio of the ZSM-5 microspheres to the metal salt in the metal salt solution is 1:0.1 - 0.24.

[0040] As a specific embodiment of the preparation method described above of the present invention, the concentration of the metal salt in the metal salt solution is 5-10% wt.

[0041] As a specific embodiment of the preparation method described above of the present invention, in step four, the metal salt includes one or a combination of several of nitrates, sulfates, or chlorides of K, Co, Ni, etc.

[0042] As a specific embodiment of the preparation method described above of the present invention, in step four, the metal salt is potassium chloride. Mixing the metal salt solution with the ZSM-5 microspheres in step four and then performing an ion exchange and sodium removal reaction can improve the stability of the ZSM-5 microspheres.

[0043] The present invention does not make specific requirements on the specific operations and parameters of cleaning and drying in steps three and four, which can be reasonably adjusted according to the actual on-site operation needs, as long as the purpose of the present invention can be achieved. For example, in some embodiments of the present invention, in step three, deionized water is used for cleaning, and the cleaning is completed when the conductivity of the cleaning solution ≤ 1000 μS / cm, and the drying temperature is 120 °C.

[0044] On the other hand, the present invention also provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by the preparation method of the sound-absorbing microsphere material described above.

[0045] The sound-absorbing microsphere material provided by the present invention includes micropores, mesopores, and macropores. Among them, the micropores and mesopores include the micropores and mesopores of the carbon nanotubes themselves and the micropores and mesopores of the molecular sieve material itself. The mesopores also include the mesopores formed by drying and dehydration, and the macropores include the macropores formed by drying and dehydration.

[0046] As a specific embodiment of the sound-absorbing microsphere material described above of the present invention, the specific surface area of the sound-absorbing microsphere material is greater than 300 m 2 / g, the particle size is 0.1-0.5 mm, the non-micropore pore volume accounts for 25%-50% of the total pore volume, and under the condition that the deformation amount is 0.05-0.15 mm, the crushing strength is not less than 0.2 N.

[0047] On yet another aspect, the present invention also provides a loudspeaker, including one or more acoustic sensors, one or more housings. The one or more acoustic sensors and the one or more housings are combined to form a rear cavity of the loudspeaker. Among them, the above-mentioned sound-absorbing microsphere material is assembled in the rear cavity of the loudspeaker.

[0048] On still another aspect, the present invention also provides an electronic device, wherein the above-mentioned sound-absorbing microsphere material is assembled in the rear cavity of the loudspeaker of the electronic device.

[0049] As a specific embodiment of the above-described electronic device of the present invention, the electronic device includes a smart phone, TWS earphones, over-ear headphones, smart glasses, smart watches, VR devices, AR devices, tablet computers or thin and light laptops.

[0050] Compared with the prior art, the beneficial technical effects that the present invention can achieve include:

[0051] 1) The present invention directly prepares the sound-absorbing microsphere material by a method of two-stage crystallization without adding an additional binder. The manufacturing process is simple, and there will be no situation where the binder blocks the pores. Therefore, the adsorption and desorption amount and rate of air molecules by the molecular sieve pores can be better exerted, and further improve the low-frequency performance of the speaker.

[0052] 2) When preparing the sound-absorbing microsphere material of the present invention, granules are first obtained by granulation in step two, and then the granules are subjected to secondary crystallization to finally obtain the sound-absorbing microsphere material. Compared with commercial sound-absorbing granules, the obtained sound-absorbing microsphere material has higher strength, and it is not easily broken into powders when used in the rear cavity of the speaker and mostly exists in the form of fragments, and the low-frequency reliability is better; and the surface of the obtained sound-absorbing microsphere material has more pores, including rich pore channels formed by adding carbon nanotubes and removing organic templates.

[0053] 3) When preparing the sound-absorbing microsphere material of the present invention, carbon nanotube pore-forming agents (especially multi-walled carbon nanotubes) are used as structure-directing agents during the primary crystallization and secondary crystallization processes respectively. The carbon nanotube pore-forming agents can form more pore structures inside the molecular sieve particles and inside the microspheres, thereby further increasing the adsorption amount and adsorption / desorption rate of air molecules by the sound-absorbing microsphere material. At the same time, the addition of the carbon nanotube pore-forming agents can also make the structure of the sound-absorbing microsphere material more fluffy, and the amount of mesopores and macropores (mesopores and macropores formed by drying and dehydration) is more than that of the particles formed by direct spray molding.

[0054] 4) When preparing the sound-absorbing microsphere material of the present invention, the slurry (containing the second carbon nanotube pore-forming agent) wrapped on the surface of the granules obtained by granulation is crystallized during the secondary crystallization process. After secondary crystallization, a complete but porous film structure is formed on the surface of the crystal grains and the entire surface of the sound-absorbing microsphere material to connect the sound-absorbing microsphere material as a whole (equivalent to the curing after the original powder and glue are formed in traditional sound-absorbing granules), so that the sound-absorbing microsphere material has better strength; at the same time, the silicon-aluminum ratio in the secondary crystallization process is greater than that in the primary crystallization process, making the obtained sound-absorbing microsphere material more hydrophobic, thereby preventing the molecular sieve from adsorbing water and blocking the pores. Description of the Drawings

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0056] Figure 1 XRD patterns of the commercially available sound-absorbing particles provided in Comparative Example 1, the sound-absorbing microsphere materials provided in Comparative Examples 1-2, and the sound-absorbing microsphere materials provided in Example 1.

[0057] Figure 2 SEM image of the sound-absorbing microsphere material provided in Example 1 of the present invention.

[0058] Figure 3 SEM image of the commercially available sound-absorbing particles provided in Comparative Example 1, i.e., NBASS-B1.

[0059] Figure 4 Nitrogen adsorption-desorption curves of the commercially available sound-absorbing particles provided in Comparative Example 1 and the sound-absorbing microsphere materials provided in Example 1.

[0060] Figure 5 Pore size distribution diagrams of the commercially available sound-absorbing particles provided in Comparative Example 1 and the sound-absorbing microsphere materials provided in Example 1. Detailed implementation manners

[0061] It should be noted that the term "including" and any of its variations in the description and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products, or devices.

[0062] The "range" disclosed in the present invention is given in the form of a lower limit and an upper limit. There can be one or more lower limits and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundary of a particular range. All ranges defined in this way are combinable, that is, any lower limit can be combined with any upper limit to form a range. For example, for a specific parameter, ranges of 60-120 and 80-110 are listed, and it is understood that ranges of 60-110 and 80-120 are also expected. In addition, if the minimum range values listed are 1 and 2, and the maximum range values listed are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0063] In the present invention, unless otherwise specified, the numerical range "a - b" represents an abbreviated representation of any combination of real numbers between a and b, where both a and b are real numbers. For example, the numerical range "0 - 5" means that all real numbers between "0 - 5" are fully listed in the present invention, and "0 - 5" is just an abbreviated representation of these numerical combinations.

[0064] In the present invention, if there is no special indication, all the embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0065] In the present invention, if there is no special indication, all the technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0066] In the present invention, if there is no special indication, all the steps mentioned herein can be carried out in sequence or randomly, but preferably in sequence. For example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out in sequence, or can also include steps (b) and (a) carried out in sequence. For example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b) and (c), or can also include steps (a), (c) and (b), or can also include steps (c), (a) and (b), etc.

[0067] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the attached tables, drawings and embodiments. The following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention. For those conditions not specified in the embodiments, they shall be carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0068] Example 1

[0069] This example provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps:

[0070] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to produce a zeolite primary crystal slurry;

[0071] Step 2: Take out 100 g of the zeolite primary crystal slurry from the reaction kettle, and add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.2 g of multi-walled carbon nanotubes with a length of 55 μm into it in sequence. Mix evenly, and then prepare particles by spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0072] Step 3: Add the dried particles and water into the reaction kettle according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, wash the obtained microspheres with deionized water until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic template agents to obtain ZSM-5 microspheres;

[0073] Step 4: According to the mass ratio of KNO3 to ZSM-5 microspheres of 1:0.15, use a KNO3 solution (6 wt%) to carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres. After the reaction is completed, wash and dry the product in sequence to obtain the finished sound-absorbing microsphere material.

[0074] Example 2

[0075] This example provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps:

[0076] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.02 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to produce a zeolite primary crystal slurry;

[0077] Step 2: Take out 100 g of the zeolite primary crystal slurry from the reaction kettle, and add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.2 g of multi-walled carbon nanotubes with a length of 55 μm into it in sequence. Mix evenly, and then prepare particles by spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0078] Step 3: Add the dried particles and water into the reaction kettle at a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, wash the obtained microspheres with deionized water successively until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic templating agents, obtaining ZSM-5 microspheres;

[0079] Step 4: Carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres using a KNO3 solution (6 wt%) at a mass ratio of KNO3 to ZSM-5 microspheres of 1:0.15. After the reaction is completed, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0080] Example 3

[0081] This example provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps:

[0082] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.22 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to generate a zeolite primary crystal slurry;

[0083] Step 2: Take out 100 g of the zeolite primary crystal slurry from the reaction kettle, add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.2 g of multi-walled carbon nanotubes with a length of 55 μm into it in sequence, mix evenly, and then prepare particles by the spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0084] Step 3: Add the dried particles and water into the reaction kettle at a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, wash the obtained microspheres with deionized water successively until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic templating agents, obtaining ZSM-5 microspheres;

[0085] Step 4: Carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres using a KNO3 solution (6 wt%) at a mass ratio of KNO3 to ZSM-5 microspheres of 1:0.15. After the reaction is completed, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0086] Example 4

[0087] This embodiment provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps:

[0088] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to generate a zeolite primary crystal slurry;

[0089] Step 2: Take out 100 g of the zeolite primary crystal slurry from the reaction kettle, and add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.16 g of multi-walled carbon nanotubes with a length of 55 μm into it in sequence and mix evenly. Then, prepare particles by the spray method, and the particle size range of the particles is 0.1 - 0.5 mm;

[0090] Step 3: Add the dried particles and water into the reaction kettle according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, wash the obtained microspheres with deionized water in sequence until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic template agents to obtain ZSM-5 microspheres;

[0091] Step 4: According to the mass ratio of KNO3 to ZSM-5 microspheres being 1:0.15, use a KNO3 solution (6 wt%) to carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres. After the reaction is completed, wash and dry the product in sequence to obtain the finished sound-absorbing microsphere material.

[0092] Example 5

[0093] This embodiment provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps:

[0094] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to generate a zeolite primary crystal slurry;

[0095] Step 2: Take out 100 g of zeolite primary crystal slurry from the reaction kettle, and successively add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.29 g of multi-walled carbon nanotubes with a length of 55 μm thereto, mix evenly, and then prepare particles by the spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0096] Step 3: Add the dried particles and water to the reaction kettle according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, successively wash the obtained microspheres with deionized water until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic templating agents, obtaining ZSM-5 microspheres;

[0097] Step 4: According to the mass ratio of KNO3 to ZSM-5 microspheres being 1:0.15, use a KNO3 solution (6 wt%) to conduct an ion exchange and sodium removal reaction on the ZSM-5 microspheres. After the reaction is completed, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0098] Example 6

[0099] This example provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps:

[0100] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide to the reaction kettle in sequence, form a gel after mixing, age at room temperature for 4 h, and then crystallize at 180 °C for 18 h to generate zeolite primary crystal slurry;

[0101] Step 2: Take out 100 g of zeolite primary crystal slurry from the reaction kettle, and successively add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.29 g of multi-walled carbon nanotubes with a length of 10 μm thereto, mix evenly, and then prepare particles by the spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0102] Step 3: Add the dried particles and water to the reaction kettle according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, successively wash the obtained microspheres with deionized water until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic templating agents, obtaining ZSM-5 microspheres;

[0103] Step 4: Carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres using a KNO3 solution (6 wt%) according to a mass ratio of KNO3 to ZSM-5 microspheres of 1:0.15. After the reaction, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0104] Example 7

[0105] This example provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps:

[0106] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to generate a zeolite primary crystal slurry.

[0107] Step 2: Take out 100 g of the zeolite primary crystal slurry from the reaction kettle, add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.29 g of multi-walled carbon nanotubes with a length of 80 μm into it in sequence, mix evenly, and then prepare particles by the spray method. The particle size range of the particles is 0.1 - 0.5 mm.

[0108] Step 3: Add the dried particles and water into the reaction kettle according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, wash the obtained microspheres with deionized water successively until the conductivity of the washing solution ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic template agents to obtain ZSM-5 microspheres.

[0109] Step 4: Carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres using a KNO3 solution (6 wt%) according to a mass ratio of KNO3 to ZSM-5 microspheres of 1:0.15. After the reaction, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0110] Comparative Example 1

[0111] This comparative example provides a commercially available sound-absorbing particle, which is the mainstream product currently used in electronic devices such as mobile phones, such as NBASS-B1 produced by Zhenjiang Best New Materials Co., Ltd.

[0112] Comparative Example 1

[0113] This comparative example provides a sound-absorbing microsphere material. Among them, the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps. The difference between this preparation method and that of Example 1 is only that multi-walled carbon nanotubes are not used as pore-forming agents in Step 1:

[0114] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to generate a zeolite primary crystal slurry;

[0115] Step 2: Take out 100 g of the zeolite primary crystal slurry from the reaction kettle, and add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.2 g of multi-walled carbon nanotubes with a length of 55 μm into it in sequence and mix evenly. Then, particles are prepared by the spray method, and the particle size range of the particles is 0.1 - 0.5 mm;

[0116] Step 3: Add the dried particles and water into the reaction kettle according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, the obtained microspheres are washed with deionized water in sequence until the conductivity of the washing liquid ≤ 1000 μS / cm, dried at 120 °C, and calcined at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic template agents to obtain ZSM-5 microspheres;

[0117] Step 4: According to the mass ratio of KNO3 to ZSM-5 microspheres being 1:0.15, use a KNO3 solution (6 wt%) to carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres. After the reaction is completed, the product is washed and dried in sequence to obtain the finished sound-absorbing microsphere material.

[0118] Comparative Example 2

[0119] This comparative example provides a sound-absorbing microsphere material. Among them, the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps. The difference between this preparation method and that of Example 1 is only that multi-walled carbon nanotubes are not used as pore-forming agents in Step 2:

[0120] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into the reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to generate a zeolite primary crystal slurry;

[0121] Step 2: Take out 100 g of zeolite primary crystal slurry from the reactor, and successively add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, and 0.067 g of tetrapropylammonium hydroxide thereto, mix evenly, and then prepare particles by the spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0122] Step 3: Add the dried particles and water to the reactor according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, successively wash the obtained microspheres with deionized water until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic templating agents to obtain ZSM-5 microspheres;

[0123] Step 4: According to the mass ratio of KNO3 to ZSM-5 microspheres being 1:0.15, use a KNO3 solution (6 wt%) to carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres. After the reaction is completed, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0124] Comparative Example 3

[0125] This comparative example provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method including the following specific steps. The difference between this preparation method and that of Example 1 is only that the mass ratio of the silicon source to the aluminum source in Steps 1 and 2 is the same:

[0126] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide to the reactor in sequence, mix to form a gel, age at room temperature for 4 h, and then crystallize at 180 °C for 18 h to generate zeolite primary crystal slurry;

[0127] Step 2: Take out 100 g of zeolite primary crystal slurry from the reactor, and successively add 10 g of silica sol (30 wt% solid content), 0.1239 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.2 g of multi-walled carbon nanotubes with a length of 55 μm thereto, mix evenly, and then prepare particles by the spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0128] Step 3: Add the dried particles and water to the reactor according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, successively wash the obtained microspheres with deionized water until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic templating agents to obtain ZSM-5 microspheres;

[0129] Step 4: Carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres using a KNO3 solution (6 wt%) according to a mass ratio of KNO3 to ZSM-5 microspheres of 1:0.15. After the reaction, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0130] Comparative Example 4

[0131] This comparative example provides a sound-absorbing microsphere material, wherein the sound-absorbing microsphere material is prepared by a preparation method comprising the following specific steps. The difference between this preparation method and that of Example 5 is only the length of the multi-walled carbon nanotubes used in Step 2:

[0132] Step 1: Add 195 g of water, 333.3 g of silica sol (30 wt% solid content), 12 g of sodium hydroxide, 4.13 g of aluminum nitrate, 0.1 g of multi-walled carbon nanotubes with a length of 0.2 μm, and 42 g of tetrapropylammonium hydroxide into a reaction kettle in sequence. After mixing, a gel is formed, aged at room temperature for 4 h, and then crystallized at 180 °C for 18 h to generate a zeolite primary crystal slurry;

[0133] Step 2: Take out 100 g of the zeolite primary crystal slurry from the reaction kettle, add 10 g of silica sol (30 wt% solid content), 0.0035 g of aluminum nitrate, 0.067 g of tetrapropylammonium hydroxide, and 0.29 g of multi-walled carbon nanotubes with a length of 120 μm into it in sequence, mix evenly, and then prepare particles by the spray method. The particle size range of the particles is 0.1 - 0.5 mm;

[0134] Step 3: Add the dried particles and water into the reaction kettle according to a weight ratio of 10:2, and crystallize at 150 °C for 60 h. After the crystallization is completed, wash the obtained microspheres with deionized water successively until the conductivity of the washing liquid ≤ 1000 μS / cm, dry at 120 °C, and calcine at 500 °C for 5 h in a nitrogen atmosphere to remove unreacted substances and organic template agents to obtain ZSM-5 microspheres;

[0135] Step 4: Carry out an ion exchange and sodium removal reaction on the ZSM-5 microspheres using a KNO3 solution (6 wt%) according to a mass ratio of KNO3 to ZSM-5 microspheres of 1:0.15. After the reaction, wash and dry the product successively to obtain the finished sound-absorbing microsphere material.

[0136] Test Example 1

[0137] This test example respectively conducts XRD analysis on the commercially available sound-absorbing particles provided in Comparative Reference 1, the sound-absorbing microsphere materials provided in Comparative Examples 1 - 2, and the sound-absorbing microsphere material provided in Example 1. The obtained XRD patterns are as Figure 1 shown. From Figure 1It can be seen that the crystal phases of the commercially available sound-absorbing particles, the sound-absorbing microsphere material obtained without using multi-walled carbon nanotubes in step 1 of comparative example 1, the sound-absorbing microsphere material obtained without using multi-walled carbon nanotubes in step 2 of comparative example 2, and the sound-absorbing microsphere material obtained with multi-walled carbon nanotubes in both steps 1 and 2 of example 1 are basically the same, and are all ZSM-5 molecular sieves with MFI structure. Other comparative examples and examples are also just adjustments to the formula, which do not affect the crystal phase of the obtained sound-absorbing microsphere material samples.

[0138] Test Example 2

[0139] In this test example, the sound-absorbing microsphere material provided in Example 1 and NBASS-B1 provided in Reference Example 1 were subjected to SEM analysis, and the obtained SEM images were as follows: Figure 2 and Figure 3 As shown. Figure 2 It can be seen that there are obvious carbon nanotube fibers and molecular sieve particles inside the sound-absorbing microsphere material, and the two exist crosswise, thus forming a complex pore structure; and in Example 1, the use of silica sol instead of the additional adhesive added during the molding process can reduce the use of adhesives, and there will be no situation where the adhesive blocks the pores, so that the molecular sieve pores can better exert the adsorption and desorption amount and rate of air molecules, thereby better improving the low-frequency performance of the speaker. Figure 3 It can be seen that the adhesive added to NBASS-B1 particles makes the molecular sieve particles adhere to each other, blocking the surface pores and hindering the flow channels of air molecules, resulting in low utilization of the molecular sieve pores and affecting the adsorption and desorption rate of air molecules by the molecular sieve pores.

[0140] Test Example 3

[0141] In this test example, the pore structure of the commercially available sound-absorbing particles provided in Reference Example 1 and the sound-absorbing microsphere material provided in Example 1 were analyzed, wherein the nitrogen adsorption-desorption curves and pore size distribution diagrams obtained are shown as follows: Figure 4 and Figure 5 As shown. Figure 4 It can be seen from the nitrogen adsorption-desorption curve shown that the sound-absorbing microsphere material provided in Example 1 has a higher adsorption amount than the commercial sound-absorbing particles provided in Reference Example 1, and its micropore mutation point is also higher than that of the commercial sound-absorbing particles, indicating that it has more micropores. This makes the sound-absorbing microsphere material provided in Example 1 have a better low-frequency improvement effect (larger ΔF0) than the existing commercial sound-absorbing particles.

[0142] from Figure 5As can be seen from the pore size distribution diagram shown, the sound-absorbing microsphere material provided in Example 1 has a higher micropore peak and a larger mesopore peak compared to the commercially available sound-absorbing particles provided in Comparative Example 1, indicating that the sound-absorbing microsphere material has more pores and a larger pore volume, thereby enabling the sound-absorbing microsphere material provided in Example 1 to have a better low-frequency improvement effect (larger ΔF0) than the existing commercially available sound-absorbing particles.

[0143] Test Example 4

[0144] In this test example, the specific surface area, total pore volume, non-micropore pore volume, strength, moisture content, ΔF0, ΔF0 after high temperature and high humidity, and ΔF0 after coexistence with VOC of the commercially available sound-absorbing particles provided in Comparative Example 1, the sound-absorbing microsphere materials provided in Comparative Examples 1-4, and the sound-absorbing microsphere materials provided in Examples 1-7 were tested by conventional methods existing in the art. The experimental data measured in this test example are shown in Table 1 below.

[0145] Among them, the specific surface area and pore volume data were obtained by testing with a static nitrogen adsorption instrument under liquid nitrogen conditions (77K); the strength was obtained by testing with a microporous spring tensile and compressive testing machine, and the load at a deformation of 0.1 mm was tested in this test example; the moisture content was measured with a moisture meter; ΔF0 was measured with an impedance meter under standard tooling conditions, and ΔF0 after high temperature and high humidity and ΔF0 after coexistence with VOC were measured with an impedance meter under standard tooling conditions after the material was subjected to high temperature and high humidity treatment and VOC; and the detailed testing methods for the above parameters can refer to the group standard T / CECA 78-2022 "Porous Sound-Absorbing Particles for Miniature Speakers" of the China Electronic Components Industry Association.

[0146] Table 1

[0147]

[0148] As can be seen from Table 1 above, compared with the commercially available sound-absorbing particles provided in Comparative Example 1, the sound-absorbing microsphere materials provided in the embodiments of the present invention have a higher specific surface area, pore volume, and a higher proportion of non-micropore pore volume (wherein micropores adsorb air, and non-micropores allow air to enter the micropores, thereby improving the adsorption and desorption efficiency of the sound-absorbing microsphere materials and exerting better performance). These physical property parameters enable the sound-absorbing microsphere materials to have better ΔF0 performance, high temperature and high humidity performance, and VOC performance when tested in a standard tooling.

[0149] Comparing the data of Example 1 and Comparative Examples 1-2 in Table 1, it can be seen that multi-walled carbon nanotubes were used in both crystallization processes of Example 1, which can endow the obtained sound-absorbing microsphere material with a larger specific surface area and more micropores, thereby making the sound-absorbing microsphere material have better ΔF0 performance; at the same time, the addition of carbon nanotubes in the primary crystallization, that is, the primary crystallization process, contributes more to the micropores and specific surface area than in the secondary crystallization, that is, the secondary crystallization process. The specific data is shown in Table 2 below.

[0150] Table 2

[0151]

[0152] Note: The contribution of adding carbon nanotubes in primary crystallization / secondary crystallization to the parameters = (the corresponding parameter in Example 1 - the corresponding parameter in the comparative example) / the addition amount of carbon nanotubes in Example 1.

[0153] Comparing the data of Example 1 and Comparative Example 3 in Table 1, it can be seen that the silicon-aluminum ratio in the two crystallization processes of Comparative Example 3 is the same, while the silicon-aluminum ratios in the two crystallization processes of Example 1 are different, and the silicon-aluminum ratio in the primary crystallization process is low, and the silicon-aluminum ratio in the secondary crystallization process is high, making the sound-absorbing microsphere material provided by Example 1 have good hydrophobicity, that is, the water content of the sound-absorbing microsphere material provided by Example 1 is significantly lower than that of the sound-absorbing microsphere material provided by Comparative Example 3; although the specific surface area, pore volume, and micropore ratio of the sound-absorbing microsphere material provided by Example 1 and the sound-absorbing microsphere material provided by Comparative Example 3 are basically the same, due to the low silicon-aluminum ratio in the secondary crystallization process when preparing the sound-absorbing microsphere material in Comparative Example 3, the obtained sound-absorbing microsphere material is more hydrophilic, so the ΔF0, ΔF0 after high temperature and high humidity, and ΔF0 after coexistence of VOCs of the sound-absorbing microsphere material provided by Comparative Example 3 are all significantly lower, that is, its acoustic performance, high temperature and high humidity performance, and VOC resistance performance are all low.

[0154] Comparing the data of Examples 2, 1, 3 and Examples 4, 1, 5 in Table 1, it can be seen that increasing the amount of multi-walled carbon nanotubes in the two crystallization processes can significantly increase the micropore content of the sound-absorbing microsphere material, increase the specific surface area and pore volume, thereby increasing the ΔF0 of the sound-absorbing microsphere material; from the comparison of the carbon nanotube content in the two crystallization processes, it can be seen that the carbon nanotube content in the primary crystallization process contributes more to the micropores, and the contribution to the micropores is more obvious when the carbon nanotubes are initially added in the primary crystallization process. As the addition amount increases, the growth rate of the contribution to the micropores is not as fast as that in the secondary crystallization process, but the increase amount is still larger in the primary crystallization process.

[0155] Comparing the data of Example 6, Example 5, Example 7 and Comparative Example 4 in Table 1, it can be seen that the contribution of the length of multi-walled carbon nanotubes to the specific surface area, pore volume, etc. of the sound-absorbing microsphere material is not linear. With the increase of the length of multi-walled carbon nanotubes, the specific surface area / pore volume of the sound-absorbing microsphere material will first increase and then decrease. When its length exceeds 0.1 mm, the multi-walled carbon nanotubes will block the pores and at the same time reduce the strength of the sound-absorbing microsphere material, making ΔF0 unable to reach the expected change value.

[0156] As mentioned above, the above are only specific embodiments of the present invention, and the scope of the invention cannot be limited by them. Therefore, the replacement of equivalent components or the equivalent changes and modifications made according to the scope of protection of the present invention should still fall within the scope covered by this patent. In addition, the technical features in the present invention can be freely combined and used between technical features, between technical features and technical inventions, and between technical inventions.

Claims

1. A preparation method of a sound-absorbing microsphere material, characterized in that, The preparation method includes the following steps: Step 1: Mix a silicon source, an aluminum source, an alkali, an organic template agent, a first carbon nanotube pore former, and water in a weight ratio of 1:0.01033 - 0.0413:0.1 - 0.15:0.32 - 0.46:0.0001 - 0.0024:1.95 to form a gel, and then subject the gel to primary crystallization to obtain a zeolite primary crystal grain slurry; Step 2: Mix the zeolite primary crystal grain slurry, the silicon source, the aluminum source, the organic template agent, and a second carbon nanotube pore former in a weight ratio of 1:0.02 - 0.05:0.000035:0.0004 - 0.001:0.0015 - 0.003, mix evenly, and granulate to obtain particles; Step 3: Mix the particles with water and perform secondary crystallization, and then successively wash, dry, and calcine the secondary crystallization product to obtain ZSM-5 microspheres; Step 4: Mix a metal salt solution with the ZSM-5 microspheres to carry out an ion exchange and sodium removal reaction, and then successively wash and dry the product to obtain the sound-absorbing microsphere material.

2. The preparation method according to claim 1, wherein The silicon source includes one or a combination of several of silica sol, sodium silicate, and tetraethyl orthosilicate; The aluminum source includes one or a combination of several of aluminum nitrate nonahydrate, sodium metaaluminate, aluminum sulfate, and triethylaluminum; The organic template agent includes tetrapropylammonium hydroxide and / or tetrapropylammonium bromide; The alkali includes sodium hydroxide and / or potassium hydroxide.

3. The preparation method according to claim 1, characterized in that, The length of the second carbon nanotube pore former is greater than the length of the first carbon nanotube pore former.

4. The preparation method according to claim 3, characterized in that, The length of the first carbon nanotube pore former is 0.1 - 1 μm, and the length of the second carbon nanotube pore former is 5 - 100 μm.

5. The preparation method according to claim 4, characterized in that, Both the first carbon nanotube pore former and the second carbon nanotube pore former are multi-walled carbon nanotubes.

6. The preparation method according to any one of claims 1-5, characterized in that, In Step 1, the primary crystallization is carried out at 150 - 200 °C for 10 - 20 h.

7. The preparation method according to any one of claims 1-5, characterized in that, In Step 1, the particle size of the zeolite primary crystal grains in the zeolite primary crystal grain slurry is 0.3 - 5 μm.

8. The preparation method according to any one of claims 1-5, characterized in that, In Step 2, the size of the particles is 0.1 - 0.5 mm.

9. The preparation method according to any one of claims 1-5, characterized in that, The silicon-aluminum mass ratio in the secondary crystallization process is higher than that in the primary crystallization process.

10. The preparation method according to any one of claims 1-5, characterized in that, In Step 3, the secondary crystallization is carried out at 100 - 180 °C for 20 - 100 h.

11. The preparation method according to any one of claims 1-5, characterized in that, In Step 3, the calcination is carried out in an inert atmosphere, the calcination temperature is 400 - 600 °C, and the calcination time is 4 - 8 h.

12. The preparation method according to any one of claims 1-5, characterized in that, In Step 3, the density of the ZSM-5 microspheres is 0.45 - 0.8 g / mL.

13. The preparation method according to any one of claims 1-5, characterized in that, In Step 4, the weight ratio of the ZSM-5 microspheres to the metal salt in the metal salt solution is 1:0.1 - 0.

24.

14. The preparation method according to claim 13, characterized in that, The concentration of the metal salt in the metal salt solution is 5 - 10 wt%.

15. The preparation method according to any one of claims 1-5, characterized in that, In Step 4, the metal salt includes one or a combination of several of nitrates, sulfates, or chlorides of K, Co, and Ni.

16. A sound-absorbing microsphere material, characterized in that, The sound-absorbing microsphere material is prepared by the preparation method of the sound-absorbing microsphere material according to any one of claims 1 - 15.

17. The sound-absorbing microsphere material according to claim 16, wherein, The specific surface area of the sound-absorbing microsphere material is greater than 300 m 2 / g, the particle size is 0.1 - 0.5 mm, the non-microporous pore volume accounts for 25% - 50% of the total pore volume, and under the condition that the deformation amount is 0.05 - 0.15 mm, the crushing strength is not less than 0.2 N.

18. A loudspeaker, comprising one or more acoustic sensors and one or more housings, wherein the one or more acoustic sensors and the one or more housings are combined to form a rear cavity of the loudspeaker, characterized in that, The sound-absorbing microsphere material according to claim 16 or 17 is assembled in the rear cavity of the loudspeaker.

19. An electronic device, characterized in that, The sound-absorbing microsphere material according to claim 16 or 17 is assembled in the rear cavity of the loudspeaker of the electronic device.

20. The electronic device according to claim 19, wherein, The electronic device includes a smart phone, TWS earphones, over-ear headphones, smart glasses, smart watch, VR device, AR device, tablet computer or thin and light laptop.

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