Acoustically reinforcing composite material and fabrication method therefor, loudspeaker, and electronic device

Abstract

An acoustically reinforcing composite material and a fabrication method therefor, a loudspeaker, and an electronic device, wherein the acoustically reinforcing composite material is formed by interweaving a fibrous material, and has a three-dimensional network structure inside, a porous powder material being attached to the surface of the fibrous material by means of a precipitation promoter. The acoustically reinforcing composite material has efficient acoustic performance, which, in terms of the porous powder material having an acoustically reinforcing function per unit mass, is superior to that of acoustically reinforcing particles commonly used in the market. The acoustically reinforcing composite material further has stable acoustic performance; and after the acoustically reinforcing composite material is stored at a high temperature and a high humidity according to the technical content recited in section 7.8.4 in the group standard Porous Sound-Absorbing Particles for Microspeakers (standard number: T / CECA 78-2022), there is no loss in terms of the acoustic performance thereof.

Description

Acoustic enhancement composite material, manufacturing method thereof, loudspeaker, and electronic device

[0001] This application claims that on September 15, 2023, the application number is 202311194810.0, and the invention name is "An acoustic enhancement composite material and its production method and loudspeaker, electronic equipment" and on September 15, 2023, the application number is 202311194809.8, and the invention name is "An acoustic enhancement material and its production method and loudspeaker, electronic equipment" and on September 15, 2023, the application number is 202311194808.3, and the invention name is " The present invention relates to an acoustic material, a method for producing the same, a loudspeaker and an electronic device”, an acoustic material, a method for producing the same, a loudspeaker and an electronic device”, an acoustic material, a method for producing the same, a loudspeaker and an electronic device”, an acoustic material, a method for producing the same, a loudspeaker and an electronic device”, an acoustic material, a method for producing the same, a loudspeaker and an electronic device”, an acoustic material, a method for producing the same, a loudspeaker and an electronic device”, and an acoustic composite material, a method for producing the same, a loudspeaker and an electronic device”, all of which are incorporated herein by reference. Technical Field

[0002] The invention relates to an acoustic enhancement composite material and a manufacturing method thereof, a loudspeaker and an electronic device, and belongs to the field of materials, in particular to the technical field of electronic acoustic materials. Background Art

[0003] As electronic products like mobile phones, tablets, and laptops become increasingly thinner and lighter, the resonant cavities of the speaker systems they use are also shrinking. As we all know, shrinking speaker cavities lead to higher resonant frequencies and lower low-frequency sound pressure sensitivity. Meanwhile, consumers are demanding increasingly higher audio quality from these devices. To address this conflict, acoustic enhancement materials have emerged.

[0004] A common method for improving the audio quality of small-cavity speakers is to use a porous powder material that efficiently absorbs and releases air molecules, using a molding process to create sound-absorbing particles with an average particle size of 200-800μm. Filling the speaker cavity with these particles is a common method. However, this method also has certain drawbacks. First, existing techniques typically use canning to fill the speaker cavity with sound-absorbing particles, a difficult process. In particular, the resonant cavity of some micro speakers is very small, with a height of hundreds of microns. Quantifying sound-absorbing particles in such a confined resonant cavity is nearly impossible. However, narrow resonant cavities often have the greatest impact on low frequencies, making them the structures most in need of sound-absorbing materials. Second, during speaker operation, traditional sound-absorbing particles vibrate at high frequencies within the cavity and collide with the inner wall, causing the particles to break and shatter, damaging the speaker unit. Furthermore, current canning processes only fill approximately 80% of the speaker module's rear cavity volume, failing to fully utilize the rear cavity space.

[0005] Therefore, providing a new acoustic enhancement composite material and its manufacturing method, loudspeaker, and electronic equipment has become a technical problem that needs to be solved urgently in this field.

[0006] Summary of the Invention

[0007] In order to solve the above-mentioned shortcomings and deficiencies, an object of the present invention is to provide an acoustic enhancement composite material.

[0008] Another object of the present invention is to provide a method for manufacturing the above-mentioned acoustic enhancement composite material.

[0009] Another object of the present invention is to provide a loudspeaker, the rear cavity of which is equipped with the above-mentioned acoustic enhancement composite material.

[0010] Another object of the present invention is to provide an electronic device, wherein the rear cavity of a speaker of the electronic device is equipped with the acoustic enhancement composite material described above.

[0011] In order to achieve the above objectives, on the one hand, the present invention provides an acoustically enhanced composite material, wherein the acoustically enhanced composite material is formed by fibrous materials interwoven with each other, and has a three-dimensional network structure inside, and a porous powder material is attached to the surface of the fibrous material through a precipitation aid.

[0012] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, based on the total weight of the acoustic enhancement composite material as 100%, the absolute dry mass proportion of the fibrous material is 19.50-85.95%, the absolute dry mass proportion of the porous powder material is 14.0-80.0%, preferably 50.0-70.0%, and the absolute dry mass proportion of the precipitation aid is 0.05-0.5%.

[0013] As a specific embodiment of the acoustic enhancement composite material described above, the diameter or width of the fibrous material is in the range of 3-70 μm, and the aspect ratio is in the range of 8-500.

[0014] As a specific embodiment of the above-mentioned acoustic enhancement composite material of the present invention, the diameter or width of the fibrous material is in the range of 8-70 μm.

[0015] As a specific embodiment of the above-mentioned acoustic enhancement composite material of the present invention, the fibrous material includes organic fibers and the like.

[0016] As a specific embodiment of the above-mentioned acoustic enhancement composite material of the present invention, the organic fibers include hydrophilic natural fibers and / or chemical synthetic fibers.

[0017] As a specific embodiment of the acoustic enhancement composite material described above, the organic fibers include hydrophilic natural fibers and chemical synthetic fibers, wherein the absolute dry weight ratio of the hydrophilic natural fibers to the chemical synthetic fibers is 100-80:0-20, preferably 100-95:0-5. When the organic fibers include both hydrophilic natural fibers and chemical synthetic fibers, the absolute dry weight ratio of the hydrophilic natural fibers to the chemical synthetic fibers is 80-98:2-20, preferably 95-98:2-5.

[0018] As a specific embodiment of the acoustic enhancement composite material of the present invention, the chemical synthetic fiber includes a chemical synthetic fiber that has not been hydrophilically modified and / or a hydrophilically modified chemical synthetic fiber obtained by hydrophilically modifying a chemical synthetic fiber that has not been hydrophilically modified, and is preferably a hydrophilically modified chemical synthetic fiber;

[0019] Wherein, the chemical synthetic fiber that has not been hydrophilically modified includes one or a combination of polypropylene fiber, polyamide fiber, polyethylene fiber, polyester fiber, polylactic acid fiber, polyetheretherketone fiber, polyphenylene sulfide fiber and polyacrylonitrile fiber;

[0020] The hydrophilically modified chemical synthetic fiber includes one or a combination of hydrophilically modified polypropylene fiber, hydrophilically modified polyamide fiber, hydrophilically modified polyethylene fiber, hydrophilically modified polyester fiber, hydrophilically modified polylactic acid fiber, hydrophilically modified polyetheretherketone fiber, hydrophilically modified polyphenylene sulfide fiber and hydrophilically modified polyacrylonitrile fiber.

[0021] As a specific embodiment of the acoustically enhanced composite material described above in the present invention, the cross-sectional shape of the chemical synthetic fiber includes circular, flat or irregular shapes, among which the irregular shapes include cross structure, skin-core structure, triangular structure, clover structure, W-shaped structure, Y-shaped structure or hollow structure, among others.

[0022] As a specific embodiment of the acoustic enhancement composite material described above, the hydrophilic natural fiber comprises one or a combination of plant fiber, regenerated cellulose fiber, and bacterial fiber, wherein the absolute dry weight ratio of the plant fiber, regenerated cellulose fiber, and bacterial fiber is 100-60:0-30:0-10, preferably 100-85:0-10:0-5. When the hydrophilic natural fiber comprises plant fiber, regenerated cellulose fiber, and bacterial fiber, the absolute dry weight ratio of the plant fiber, regenerated cellulose fiber, and bacterial fiber is 60-98:1.5-30:0.5-10, preferably 85-98:1.5-10:0.5-5.

[0023] As a specific embodiment of the acoustic enhancement composite material described above, when the fibrous material is plant fiber and hydrophilically modified chemical synthetic fiber, the absolute dry mass ratio of the two is 98-70:2-30, preferably 95-80:5-20.

[0024] As a specific embodiment of the acoustic enhancement composite material described above, the plant fibers include fine plant fibers and / or coarse plant fibers, wherein the diameter or width of the fine plant fibers is greater than or equal to 8 μm and less than 30 μm, and the diameter or width of the coarse plant fibers is in the range of 30-70 μm;

[0025] The absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 100-0:0-100, preferably 100-30:0-70. When the plant fibers include both fine plant fibers and coarse plant fibers, the absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 30-80:20-70.

[0026] As a specific embodiment of the above-mentioned acoustic enhancement composite material of the present invention, the aspect ratio of the plant fiber is 8-150.

[0027] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reeds and cotton.

[0028] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the regenerated cellulose fiber includes one or a combination of viscose fiber, modal fiber, lyocell fiber, acetate fiber, cupro fiber and Tencel fiber.

[0029] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the bacterial fiber includes cellulose fiber synthesized by microorganisms under certain conditions using nutrients required for bacterial growth and reproduction as raw materials, wherein the microorganisms include Acetobacter, Agrobacterium, Rhizobium or Sarcina, etc.

[0030] As a specific embodiment of the acoustic enhancement composite material described above, the fibrous material includes one or a combination of inorganic fibers, plant fibers, and chemical fibers of composite components.

[0031] As a specific embodiment of the acoustic enhancement composite material described above, the diameter or width of the inorganic fibers is in the range of 3-45 μm, and the aspect ratio is in the range of 10-500.

[0032] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the inorganic fiber includes one or a combination of basalt fiber, glass fiber, quartz fiber, asbestos fiber, volcanic rock fiber, metal fiber, alumina fiber and carbon fiber.

[0033] As a specific embodiment of the above-mentioned acoustic enhancement composite material of the present invention, the diameter or width of the plant fiber is in the range of 8-70 μm, and the aspect ratio is in the range of 8-150.

[0034] As a specific embodiment of the acoustic enhancement composite material described above, the moisture absorption ratio of the plant fiber is 16.0-31.5%, preferably 20.0-31.5%.

[0035] As a specific embodiment of the acoustically enhanced composite material described above in the present invention, the plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reeds and cotton.

[0036] As a specific embodiment of the acoustic enhancement composite material described above, the diameter or width of the chemical fibers of the composite component is in the range of 10-70 μm, and the aspect ratio is in the range of 10-200.

[0037] As a specific embodiment of the acoustic enhancement composite material described above, the chemical fibers of the composite component include one or a combination of chemical fibers of a skin-core structure, a parallel structure, or a sea-island structure.

[0038] As a specific embodiment of the acoustic enhancement composite material described above, the chemical fibers of the parallel structure composite components include chemical fibers with a melting point not higher than 140°C and chemical fibers with a melting point not lower than 150°C.

[0039] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the chemical fiber with a melting point not higher than 140°C includes polyethylene fiber and / or modified polyester fiber, etc., and the chemical fiber with a melting point not lower than 150°C includes ordinary polyester fiber and / or polypropylene fiber, etc.

[0040] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the material of the matrix of the chemical fiber of the island structure composite component includes chemical fibers with a melting point not higher than 140°C, and the material of the dispersed phase includes chemical fibers with a melting point not lower than 150°C.

[0041] As a specific embodiment of the acoustic enhancement composite material described above, the matrix material includes polyethylene fiber and / or modified polyester fiber, and the dispersed phase material includes ordinary polyester fiber and / or polypropylene fiber.

[0042] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the chemical fiber of the skin-core structure composite component includes a core layer and a skin layer covering the core layer, and the material of the skin layer includes chemical fiber with a melting point not higher than 140°C, and the material of the core layer includes chemical fiber with a melting point not lower than 150°C.

[0043] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the core layer includes ordinary polyester fibers and / or polypropylene fibers, and the skin layer includes polyethylene fibers and / or modified polyester fibers.

[0044] As a specific embodiment of the acoustic enhancement composite material described above, the absolute dry mass ratio of the plant fiber to the chemical fiber of the composite component is 98-60:2-40.

[0045] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the porous powder material includes one or a combination of several of zeolite molecular sieve, activated silica, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, alumina, hydrogel, aerogel, etc.

[0046] As a specific embodiment of the acoustic enhancement composite material described above, the zeolite molecular sieve has a particle size of 0.5-10 μm, and contains micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

[0047] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the zeolite molecular sieve includes one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve and MTT structure molecular sieve.

[0048] As a specific embodiment of the acoustic enhancement composite material described above, the precipitation aid includes one or a combination of polyacrylamide, starch, polyethyleneimine, polyimide, guar gum, and the like.

[0049] As a specific embodiment of the acoustic enhancement composite material of the present invention, the gram weight range of the acoustic enhancement composite material is 50-1200 g / m 2 .

[0050] As a specific embodiment of the acoustic enhancement composite material described above in the present invention, the shape of the acoustic enhancement composite material includes sheet, block or irregular shape.

[0051] On the other hand, the present invention also provides a method for preparing the above-mentioned acoustic enhancement composite material, wherein the preparation method comprises:

[0052] Step 1: Dispersing the fibrous material, the porous powder material and the precipitation aid in water respectively to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0053] Step 2: adding the porous powder material dispersion to the fibrous material dispersion and mixing them evenly, then adding the precipitation aid dispersion and mixing them evenly, so that the fibrous materials are interwoven with each other and the porous powder material is precipitated on the surface of the fibrous material;

[0054] Step 3: Filter the mixed solution obtained in step 2 to obtain a precursor material;

[0055] Step 4: Drying the precursor material to obtain an acoustically enhanced composite material.

[0056] As a specific embodiment of the above-mentioned production method of the present invention, when the fibrous material includes chemical fibers of a composite component, the production method further includes:

[0057] Step 5: subjecting the acoustic enhancement material to a high-temperature treatment at a temperature not lower than the melting point of the cortex contained in the chemical fiber of the composite component, so that the cortex of the chemical fiber of the composite component melts while the core does not melt.

[0058] On the other hand, the present invention also provides a speaker, comprising one or more acoustic sensors and one or more shells, wherein the one or more acoustic sensors and the one or more shells are combined to form a speaker back cavity, wherein the speaker back cavity is equipped with the acoustically enhanced composite material described above.

[0059] In yet another aspect, the present invention further provides an electronic device, wherein the above-mentioned acoustic enhancement composite material is installed in the rear cavity of a speaker of the electronic device.

[0060] As a specific embodiment of the electronic device described above in the present invention, the electronic device includes a smart phone, TWS earphones, headphones, smart glasses, smart watches, VR devices, AR devices, tablet computers or thin and light laptops, etc.

[0061] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0062] In a first aspect, a first scheme of the present invention provides an acoustically enhanced composite material, wherein the acoustically enhanced composite material is formed by fibrous materials interwoven with each other, has a three-dimensional network structure inside, and a porous powder material is attached to the surface of the fibrous material through a precipitation aid.

[0063] In the acoustic enhancement composite material provided by the present invention, the porous powder material is attached to the three-dimensional network structure and the surface of the acoustic enhancement composite material.

[0064] In combination with the first scheme, in a feasible embodiment, based on the total weight of the acoustic enhancement composite material as 100%, the absolute dry mass of the fibrous material accounts for 19.50-85.95%, the absolute dry mass of the porous powder material accounts for 14.0-80.0%, and the absolute dry mass of the precipitation aid accounts for 0.05-0.5%.

[0065] In the present invention, the smaller the diameter or width of the fibrous material, the smaller the aspect ratio. Under the premise of the same mass, the specific surface area of ​​the fibrous material is larger, which means that it has more surface area to interact with the porous powder material with acoustic enhancement function; and the larger the diameter or width of the fibrous material, the larger the aspect ratio, which means that the mutual interweaving between the fibrous materials is richer, the three-dimensional network structure formed is more complex, and the physical strength of the acoustic enhancement composite material obtained is better. However, if the diameter or width of the fibrous material is too large, the surface of the acoustic enhancement composite material prepared therefrom is rougher and uneven, and the aspect ratio of the fibrous material is too large, then the fibrous material is difficult to disperse in water, the fibrous materials are entangled with each other, and it is difficult to disperse into single fibers. Accordingly, in combination with the first scheme, in a feasible embodiment, the diameter or width of the fibrous material is in the range of 8-70 μm, and the aspect ratio is in the range of 8-500, preferably 8-150. In the present invention, "aspect ratio" refers to the ratio of the length to the diameter of the fibrous material. In some special fibrous materials, "aspect ratio" can also be understood as the ratio of its length to width.

[0066] In combination with the first embodiment, the present invention provides a second embodiment, in which the fibrous material includes organic fibers.

[0067] In combination with the first and second embodiments, in one feasible embodiment, the organic fibers include hydrophilic natural fibers and chemical synthetic fibers, wherein the absolute dry weight ratio of the hydrophilic natural fibers to the chemical synthetic fibers is 100-80:0-20, preferably 100-95:0-5. Preferably, the organic fibers are hydrophilic natural fibers. When the organic fibers include both hydrophilic natural fibers and chemical synthetic fibers, the absolute dry weight ratio of the hydrophilic natural fibers to the chemical synthetic fibers is 80-98:2-20, preferably 95-98:2-5.

[0068] In combination with the first and second embodiments, in a feasible embodiment, the chemical synthetic fiber includes a chemical synthetic fiber that has not been hydrophilically modified and / or a hydrophilically modified chemical synthetic fiber obtained by hydrophilically modifying a chemical synthetic fiber that has not been hydrophilically modified, and is preferably a hydrophilically modified chemical synthetic fiber;

[0069] The chemical synthetic fibers that have not been hydrophilically modified include one or a combination of polypropylene fibers, polyamide fibers, polyethylene fibers, polyester fibers, polylactic acid fibers, polyetheretherketone fibers, polyphenylene sulfide fibers, and polyacrylonitrile fibers.

[0070] The present invention does not impose specific requirements on the hydrophilic modification agent used to hydrophilically modify the chemical synthetic fiber, and a reasonable selection can be made based on actual operational needs. For example, in some embodiments of the present invention, the hydrophilic modification agent can be maleic anhydride, and accordingly, the hydrophilically modified chemical synthetic fiber can be maleic anhydride-modified polypropylene fiber or maleic anhydride-modified polyester fiber.

[0071] The characteristics of the chemical synthetic fibers used in the present invention are that there is no significant interaction force between them, such as hydrogen bonding and electrostatic attraction, and their density is relatively low. The mechanical interweaving force between such fibrous materials is the main interaction force, and a three-dimensional spatial structure with high porosity, i.e., a three-dimensional network structure, can be constructed, which facilitates air circulation.

[0072] In combination with the first and second schemes, in a feasible embodiment, the cross-sectional shape of the chemical synthetic fiber includes circular, flat or irregular shapes, among which the irregular shapes include cross structure, skin-core structure, triangular structure, clover structure, W-shaped structure, Y-shaped structure or hollow structure, among others.

[0073] In combination with the first and second embodiments, in a feasible embodiment, the hydrophilic natural fiber includes one or a combination of plant fiber, regenerated cellulose fiber, and bacterial fiber, wherein the absolute dry weight ratio of the plant fiber, regenerated cellulose fiber, and bacterial fiber is 100-60:0-30:0-10, preferably 100-85:0-10:0-5. When the hydrophilic natural fiber includes plant fiber, regenerated cellulose fiber, and bacterial fiber at the same time, the absolute dry weight ratio of the plant fiber, regenerated cellulose fiber, and bacterial fiber is 60-98:1.5-30:0.5-10, preferably 85-98:1.5-10:0.5-5.

[0074] The hydrophilic natural fibers used in this invention include plant fibers, regenerated cellulose fibers, and bacterial fibers. These fibrous materials contain a high number of hydrophilic groups, such as hydroxyl and carboxyl groups, in their chemical structures. When an acoustically enhanced composite material made from these hydrophilic natural fibers is assembled into the speaker's rear cavity, water molecules in the air are preferentially absorbed and fixed by the hydrophilic natural fibers during use. This reduces the performance degradation of the porous powder particles caused by these molecules, significantly extending the service life of the acoustically enhanced composite material within the rear cavity.

[0075] In combination with the first and second solutions, in a feasible embodiment, the plant fibers can be divided into two categories according to their diameter or width, including fine plant fibers and / or coarse plant fibers, wherein the diameter or width of the fine plant fibers is greater than or equal to 8 μm and less than 30 μm, and the diameter or width of the coarse plant fibers is in the range of 30-70 μm;

[0076] The absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 100-0:0-100, preferably 100-30:0-70. When the plant fibers include both fine plant fibers and coarse plant fibers, the absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 30-80:20-70.

[0077] In combination with the first and second solutions, in a feasible implementation manner, the aspect ratio of the plant fiber is 8-150.

[0078] In combination with the first and second options, in a feasible embodiment, the plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reeds and cotton.

[0079] The method for preparing plant fibers from natural plants is a conventional method and can be reasonably adjusted based on the characteristics of the natural plants and the properties of the target plant fibers. For example, in some embodiments of the present invention, the preparation method includes removing lignin and most hemicellulose from the natural plants, followed by bleaching or unbleaching to obtain a fibrous material primarily composed of cellulose, i.e., the plant fibers.

[0080] In the present invention, the regenerated cellulose fiber is a fibrous fiber material obtained by further processing high-purity cellulose derived from natural plants. Combining the first and second embodiments, in one feasible embodiment, the regenerated cellulose fiber includes one or a combination of viscose fiber, modal fiber, lyocell fiber, acetate fiber, cupro fiber, and Tencel fiber.

[0081] In the present invention, the bacterial fiber is a fibrous material derived from bacterial microorganisms, produced using biological methods. Combining the first and second embodiments, in one feasible embodiment, the bacterial fiber comprises cellulose fibers synthesized by microorganisms under certain conditions, using nutrients required for bacterial growth and reproduction as raw materials. The microorganisms include Acetobacter, Agrobacterium, Rhizobium, or Sarcina.

[0082] In combination with the first and second schemes, in a feasible embodiment, the fibrous material can be a single organic fiber, or a combination of multiple organic fibers, or a combination of organic fibers with different diameters or widths, and / or different aspect ratios. Preferably, the fibrous material includes a combination of two or more organic fibers with different diameters or widths, and / or different aspect ratios.

[0083] The porous powder material used in the present invention has an acoustic enhancement function and can be selected from porous powder materials commonly used in the art for preparing acoustic enhancement materials. Combining the first and second embodiments, in one feasible embodiment, the porous powder material includes one or a combination of zeolite molecular sieves, activated silica, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, aluminum oxide, hydrogel, and aerogel.

[0084] Combining the first and second solutions, in a feasible embodiment, the zeolite molecular sieve has a particle size of 0.5-10 μm, including micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

[0085] Combining the first and second options, in a feasible embodiment, the zeolite molecular sieve includes one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve and MTT structure molecular sieve.

[0086] In combination with the first and second solutions, in a feasible implementation manner, the precipitation aid includes one or a combination of polyacrylamide, starch, polyethyleneimine, polyimide and guar gum.

[0087] Combining the first and second solutions, in a feasible embodiment, the gram weight range of the acoustic enhancement composite material is 50-1200 g / m 2 .

[0088] Combining the first and second embodiments, in one feasible embodiment, the acoustically enhanced composite material can be in the form of a sheet, block, or irregular shape. When applying this acoustically enhanced composite material, those skilled in the art can reasonably select an acoustically enhanced composite material of an appropriate shape as needed. Alternatively, those skilled in the art can combine the preparation method provided herein with conventional methods to obtain an acoustically enhanced composite material of a desired shape.

[0089] In combination with the first and second solutions, in a feasible embodiment, the acoustic enhancement composite material is formed by interwoven hydrophilic fibers, having a three-dimensional network structure inside, and porous powder material is attached to the surface of the hydrophilic fibers via a precipitation aid;

[0090] Wherein, the hydrophilic fibers include hydrophilic natural fibers and / or hydrophilically modified chemical synthetic fibers.

[0091] In the acoustic enhancement composite material provided by the present invention, the porous powder material is attached to the three-dimensional network structure and the surface of the acoustic enhancement composite material.

[0092] In combination with the first and second schemes, in a feasible embodiment, based on the total weight of the acoustic enhancement composite material as 100%, the absolute dry mass of the hydrophilic fiber accounts for 19.50-85.95%, the absolute dry mass of the porous powder material accounts for 14.0-80.0%, and the absolute dry mass of the precipitation aid accounts for 0.05-0.5%.

[0093] In the present invention, the smaller the diameter or width of the hydrophilic fiber, the smaller the aspect ratio, and under the premise of the same mass, the larger the specific surface area of ​​the hydrophilic fiber, which means that it has more surface area to interact with the porous powder material with acoustic enhancement function; and the larger the diameter or width of the hydrophilic fiber, the larger the aspect ratio, which means that the mutual interweaving between the hydrophilic fibers is richer, the three-dimensional network structure formed is more complex, and the physical strength of the obtained acoustic enhancement composite material is better. However, if the diameter or width of the hydrophilic fiber is too large, the surface of the acoustic enhancement composite material prepared therefrom is rougher and uneven, and the aspect ratio of the hydrophilic fiber is too large, then the hydrophilic fiber is difficult to disperse in water, the hydrophilic fibers are entangled with each other, and it is difficult to disperse into a single fiber. Accordingly, in combination with the first and second schemes, in a feasible embodiment, the diameter or width of the hydrophilic fiber is in the range of 8-70 μm, and the aspect ratio is in the range of 8-500, preferably 8-150. In the present invention, "aspect ratio" refers to the ratio of the length to the diameter of the hydrophilic fiber. In some special hydrophilic fibers, "aspect ratio" can also be understood as the ratio of its length to width.

[0094] In combination with the first and second embodiments, in one feasible embodiment, the absolute dry weight ratio of the hydrophilic natural fiber to the hydrophilically modified chemically modified fiber is 100-80:0-20, preferably 100-95:0-5. When the organic fibers include both hydrophilic natural fibers and chemically modified fibers, the absolute dry weight ratio of the hydrophilic natural fiber to the chemically modified fiber is 80-98:2-20, preferably 95-98:2-5.

[0095] In combination with the first and second schemes, in a feasible embodiment, the hydrophilically modified chemical synthetic fiber includes one or a combination of hydrophilically modified polypropylene fiber, hydrophilically modified polyamide fiber, hydrophilically modified polyethylene fiber, hydrophilically modified polyester fiber, hydrophilically modified polylactic acid fiber, hydrophilically modified polyetheretherketone fiber, hydrophilically modified polyphenylene sulfide fiber and hydrophilically modified polyacrylonitrile fiber.

[0096] The present invention does not impose specific requirements on the hydrophilic modification agent used to hydrophilically modify the chemical synthetic fiber, and a reasonable selection can be made based on actual operational needs. For example, in some embodiments of the present invention, the hydrophilic modification agent can be maleic anhydride, and accordingly, the hydrophilically modified chemical synthetic fiber can be maleic anhydride-modified polypropylene fiber or maleic anhydride-modified polyester fiber.

[0097] The characteristics of the hydrophilic modified chemical synthetic fibers used in the present invention are that there is no significant interaction force between them, such as hydrogen bonding and electrostatic attraction, and their density is relatively low. The mechanical interweaving force between such fibrous materials is the main interaction force, and a three-dimensional spatial structure with high porosity, i.e., a three-dimensional network structure, can be constructed, which is conducive to the circulation of air.

[0098] In combination with the first and second schemes, in a feasible embodiment, the cross-sectional shape of the hydrophilically modified chemical synthetic fiber includes a circular, flat or irregular shape, wherein the irregular shape includes a cross structure, a skin-core structure, a triangular structure, a clover structure, a W-shaped structure, a Y-shaped structure or a hollow structure, etc.

[0099] In combination with the first and second embodiments, in a feasible embodiment, the hydrophilic natural fiber includes one or a combination of plant fiber, regenerated cellulose fiber, and bacterial fiber, wherein the absolute dry weight ratio of the plant fiber, regenerated cellulose fiber, and bacterial fiber is 100-60:0-30:0-10, preferably 100-85:0-10:0-5. When the hydrophilic natural fiber includes plant fiber, regenerated cellulose fiber, and bacterial fiber at the same time, the absolute dry weight ratio of the plant fiber, regenerated cellulose fiber, and bacterial fiber is 60-98:1.5-30:0.5-10, preferably 85-98:1.5-10:0.5-5.

[0100] The hydrophilic natural fibers used in this invention include plant fibers, regenerated cellulose fibers, and bacterial fibers. These fibrous materials contain a high number of hydrophilic groups, such as hydroxyl and carboxyl groups, in their chemical structures. When an acoustically enhanced composite material made from these hydrophilic natural fibers is assembled into the speaker's rear cavity, water molecules in the air are preferentially absorbed and fixed by the hydrophilic natural fibers during use. This reduces the performance degradation of the porous powder particles caused by these molecules, significantly extending the service life of the acoustically enhanced composite material within the rear cavity.

[0101] In combination with the first and second solutions, in a feasible embodiment, the plant fibers can be divided into two categories according to their diameter or width, including fine plant fibers and / or coarse plant fibers, wherein the diameter or width of the fine plant fibers is greater than or equal to 8 μm and less than 30 μm, and the diameter or width of the coarse plant fibers is in the range of 30-70 μm;

[0102] The absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 100-0:0-100, preferably 100-30:0-70. When the plant fibers include both fine plant fibers and coarse plant fibers, the absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 30-80:20-70.

[0103] In combination with the first and second solutions, in a feasible implementation manner, the aspect ratio of the plant fiber is 8-150.

[0104] In combination with the first and second options, in a feasible embodiment, the plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reeds and cotton.

[0105] The method for preparing plant fibers from natural plants is a conventional method and can be reasonably adjusted based on the characteristics of the natural plants and the properties of the target plant fibers. For example, in some embodiments of the present invention, the preparation method includes removing lignin and most hemicellulose from the natural plants, followed by bleaching or unbleaching to obtain a fibrous material primarily composed of cellulose, i.e., the plant fibers.

[0106] In the present invention, the regenerated cellulose fiber is a fibrous fiber material obtained by further processing high-purity cellulose derived from natural plants. Combining the first and second embodiments, in one feasible embodiment, the regenerated cellulose fiber includes one or a combination of viscose fiber, modal fiber, lyocell fiber, acetate fiber, cupro fiber, and Tencel fiber.

[0107] In the present invention, the bacterial fiber is a fibrous material derived from bacterial microorganisms, produced using biological methods. Combining the first and second embodiments, in one feasible embodiment, the bacterial fiber comprises cellulose fibers synthesized by microorganisms under certain conditions, using nutrients required for bacterial growth and reproduction as raw materials. The microorganisms include Acetobacter, Agrobacterium, Rhizobium, or Sarcina.

[0108] In combination with the first and second schemes, in a feasible embodiment, the hydrophilic fiber can be selected from one of the hydrophilic natural fibers and / or hydrophilic modified chemical synthetic fibers, or a combination of multiple fibers can be selected, or a combination of fibers with different diameters or widths, and / or different aspect ratios can be selected. Preferably, the hydrophilic fiber includes a combination of two or more fibers with different diameters or widths, and / or different aspect ratios.

[0109] The porous powder material used in the present invention has an acoustic enhancement function and can be selected from porous powder materials commonly used in the art for preparing acoustic enhancement materials. Combining the first and second embodiments, in one feasible embodiment, the porous powder material includes one or a combination of zeolite molecular sieves, activated silica, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, aluminum oxide, hydrogel, and aerogel.

[0110] Combining the first and second solutions, in a feasible embodiment, the zeolite molecular sieve has a particle size of 0.5-10 μm, including micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

[0111] Combining the first and second options, in a feasible embodiment, the zeolite molecular sieve includes one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve and MTT structure molecular sieve.

[0112] In combination with the first and second solutions, in a feasible implementation manner, the precipitation aid includes one or a combination of polyacrylamide, starch, polyethyleneimine, polyimide and guar gum.

[0113] Combining the first and second solutions, in a feasible embodiment, the gram weight range of the acoustic enhancement composite material is 50-1200 g / m 2 .

[0114] Combining the first and second embodiments, in one feasible embodiment, the acoustically enhanced composite material can be in the form of a sheet, block, or irregular shape. When applying this acoustically enhanced composite material, those skilled in the art can reasonably select an acoustically enhanced composite material of an appropriate shape as needed. Alternatively, those skilled in the art can combine the preparation method provided herein with conventional methods to obtain an acoustically enhanced composite material of a desired shape.

[0115] In combination with the first and second solutions, in a feasible embodiment, the acoustic enhancement composite material is formed by interweaving fibrous materials, having a three-dimensional network structure inside, and porous powder material is attached to the surface of the fibrous material via a precipitation aid;

[0116] Wherein, the fibrous material is a hydrophilically modified chemical synthetic fiber, or a combination of a non-hydrophilically modified chemical synthetic fiber and a hydrophilically modified chemical synthetic fiber.

[0117] In the acoustic enhancement composite material provided by the present invention, the porous powder material is attached to the three-dimensional network structure and the surface of the acoustic enhancement composite material.

[0118] In combination with the first and second schemes, in a feasible embodiment, based on the total weight of the acoustic enhancement composite material as 100%, the absolute dry mass of the fibrous material accounts for 19.50-85.95%, the absolute dry mass of the porous powder material accounts for 14.0-80.0%, and the absolute dry mass of the precipitation aid accounts for 0.05-0.5%.

[0119] In the present invention, the smaller the diameter or width of the fibrous material, the smaller the aspect ratio. Under the premise of the same mass, the specific surface area of ​​the fibrous material is larger, which means that it has more surface area to interact with the porous powder material with acoustic enhancement function; and the larger the diameter or width of the fibrous material, the larger the aspect ratio, which means that the mutual interweaving between the fibrous materials is richer, the three-dimensional network structure formed is more complex, and the physical strength of the acoustic enhancement composite material obtained is better. However, if the diameter or width of the fibrous material is too large, the surface of the acoustic enhancement composite material prepared therefrom is rougher and uneven, and the aspect ratio of the fibrous material is too large, then the fibrous material is difficult to disperse in water, the fibrous materials are entangled with each other, and it is difficult to disperse into single fibers. Accordingly, in combination with the first and second schemes, in a feasible embodiment, the diameter or width of the fibrous material is in the range of 8-70 μm, and the aspect ratio is in the range of 8-500, preferably 8-150. In the present invention, "aspect ratio" refers to the ratio of the length to the diameter of the fibrous material. In some special fibrous materials, "aspect ratio" can also be understood as the ratio of its length to width.

[0120] In combination with the first and second schemes, in a feasible embodiment, the chemical synthetic fiber that has not been hydrophilically modified includes one or a combination of several of polypropylene fiber, polyamide fiber, polyethylene fiber, polyester fiber, polylactic acid fiber, polyetheretherketone fiber, polyphenylene sulfide fiber and polyacrylonitrile fiber.

[0121] In combination with the first and second schemes, in a feasible embodiment, the hydrophilically modified chemical synthetic fiber includes one or a combination of hydrophilically modified polypropylene fiber, hydrophilically modified polyamide fiber, hydrophilically modified polyethylene fiber, hydrophilically modified polyester fiber, hydrophilically modified polylactic acid fiber, hydrophilically modified polyetheretherketone fiber, hydrophilically modified polyphenylene sulfide fiber and hydrophilically modified polyacrylonitrile fiber.

[0122] The present invention does not impose specific requirements on the hydrophilic modification agent used to hydrophilically modify the chemical synthetic fiber, and a reasonable selection can be made based on actual operational needs. For example, in some embodiments of the present invention, the hydrophilic modification agent can be maleic anhydride, and accordingly, the hydrophilically modified chemical synthetic fiber can be maleic anhydride-modified polypropylene fiber or maleic anhydride-modified polyester fiber.

[0123] The characteristics of the chemical synthetic fibers used in the present invention are that there is no significant interaction force between them, such as hydrogen bonding and electrostatic attraction, and their density is relatively low. The mechanical interweaving force between such fibrous materials is the main interaction force, and a three-dimensional spatial structure with high porosity, i.e., a three-dimensional network structure, can be constructed, which facilitates air circulation.

[0124] In combination with the first and second schemes, in a feasible embodiment, the cross-sectional shape of the fibrous material includes a circular, flat or irregular shape, among which the irregular shape includes a cross structure, a skin-core structure, a triangular structure, a clover structure, a W-shaped structure, a Y-shaped structure or a hollow structure, among others.

[0125] In combination with the first and second schemes, in a feasible embodiment, the fibrous material can be a single chemical synthetic fiber, or a combination of multiple chemical synthetic fibers, or a combination of chemical synthetic fibers with different diameters or widths, and / or different aspect ratios. Preferably, the chemical synthetic fibers include a combination of two or more chemical synthetic fibers with different diameters or widths, and / or different aspect ratios.

[0126] The porous powder material used in the present invention has an acoustic enhancement function and can be selected from porous powder materials commonly used in the art for preparing acoustic enhancement materials. Combining the first and second embodiments, in one feasible embodiment, the porous powder material includes one or a combination of zeolite molecular sieves, activated silica, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, aluminum oxide, hydrogel, and aerogel.

[0127] Combining the first and second solutions, in a feasible embodiment, the zeolite molecular sieve has a particle size of 0.5-10 μm, including micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

[0128] Combining the first and second options, in a feasible embodiment, the zeolite molecular sieve includes one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve and MTT structure molecular sieve.

[0129] In combination with the first and second solutions, in a feasible implementation manner, the precipitation aid includes one or a combination of polyacrylamide, starch, polyethyleneimine, polyimide and guar gum.

[0130] Combining the first and second solutions, in a feasible embodiment, the gram weight range of the acoustic enhancement composite material is 50-1200 g / m 2 .

[0131] Combining the first and second embodiments, in one feasible embodiment, the acoustically enhanced composite material can be in the form of a sheet, block, or irregular shape. When applying this acoustically enhanced composite material, those skilled in the art can reasonably select an acoustically enhanced composite material of an appropriate shape as needed. Alternatively, those skilled in the art can combine the preparation method provided herein with conventional methods to obtain an acoustically enhanced composite material of a desired shape.

[0132] In combination with the first and second solutions, in a feasible embodiment, the acoustic enhancement composite material is formed by interweaving fibrous materials, having a three-dimensional network structure inside, and porous powder material is attached to the surface of the fibrous material via a precipitation aid;

[0133] Wherein, the fibrous material is plant fiber and hydrophilic modified chemical synthetic fiber.

[0134] In the acoustic enhancement composite material provided by the present invention, the porous powder material is attached to the three-dimensional network structure and the surface of the acoustic enhancement composite material.

[0135] In combination with the first and second schemes, in a feasible embodiment, based on the total weight of the acoustic enhancement composite material as 100%, the absolute dry mass of the fibrous material accounts for 19.50-85.95%, the absolute dry mass of the porous powder material accounts for 14.0-80.0%, and the absolute dry mass of the precipitation aid accounts for 0.05-0.5%.

[0136] In the present invention, the smaller the diameter or width of the fibrous material, the smaller the aspect ratio. Under the premise of the same mass, the specific surface area of ​​the fibrous material is larger, which means that it has more surface area to interact with the porous powder material with acoustic enhancement function; and the larger the diameter or width of the fibrous material, the larger the aspect ratio, which means that the mutual interweaving between the fibrous materials is richer, the three-dimensional network structure formed is more complex, and the physical strength of the acoustic enhancement composite material obtained is better. However, if the diameter or width of the fibrous material is too large, the surface of the acoustic enhancement composite material prepared therefrom is rougher and uneven, and the aspect ratio of the fibrous material is too large, then the fibrous material is difficult to disperse in water, the fibrous materials are entangled with each other, and it is difficult to disperse into single fibers. Accordingly, in combination with the first and second schemes, in a feasible embodiment, the diameter or width of the fibrous material is in the range of 8-70 μm, and the aspect ratio is in the range of 8-500, preferably 8-150. In the present invention, "aspect ratio" refers to the ratio of the length to the diameter of the fibrous material. In some special fibrous materials, "aspect ratio" can also be understood as the ratio of its length to width.

[0137] In combination with the first and second schemes, in a feasible embodiment, the hydrophilically modified chemical synthetic fiber includes one or a combination of hydrophilically modified polypropylene fiber, hydrophilically modified polyamide fiber, hydrophilically modified polyethylene fiber, hydrophilically modified polyester fiber, hydrophilically modified polylactic acid fiber, hydrophilically modified polyetheretherketone fiber, hydrophilically modified polyphenylene sulfide fiber and hydrophilically modified polyacrylonitrile fiber.

[0138] The present invention does not impose specific requirements on the hydrophilic modification agent used to hydrophilically modify the chemical synthetic fiber, and a reasonable selection can be made based on actual operational needs. For example, in some embodiments of the present invention, the hydrophilic modification agent can be maleic anhydride, and accordingly, the hydrophilically modified chemical synthetic fiber can be maleic anhydride-modified polypropylene fiber or maleic anhydride-modified polyester fiber.

[0139] The characteristics of the hydrophilic modified chemical synthetic fibers used in the present invention are that there is no significant interaction force between them, such as hydrogen bonding and electrostatic attraction, and their density is relatively low. The mechanical interweaving force between such fibrous materials is the main interaction force, and a three-dimensional spatial structure with high porosity, i.e., a three-dimensional network structure, can be constructed, which is conducive to the circulation of air.

[0140] In combination with the first and second schemes, in a feasible embodiment, the cross-sectional shape of the hydrophilically modified chemical synthetic fiber includes a circular, flat or irregular shape, wherein the irregular shape includes a cross structure, a skin-core structure, a triangular structure, a clover structure, a W-shaped structure, a Y-shaped structure or a hollow structure, etc.

[0141] The plant fibers used in this invention contain a high number of hydrophilic groups, such as hydroxyl and carboxyl groups. When the acoustically enhanced composite material containing these fibers is assembled into the rear cavity of a loudspeaker, water molecules in the air are preferentially absorbed and fixed by the plant fibers during actual use. This reduces the performance degradation of the porous powder particles caused by water molecules and significantly increases the service life of the acoustically enhanced composite material within the rear cavity.

[0142] In combination with the first and second solutions, in a feasible embodiment, the plant fibers can be divided into two categories according to their diameter or width, including fine plant fibers and / or coarse plant fibers, wherein the diameter or width of the fine plant fibers is greater than or equal to 8 μm and less than 30 μm, and the diameter or width of the coarse plant fibers is in the range of 30-70 μm;

[0143] The absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 100-0:0-100, preferably 100-30:0-70. When the plant fibers include both fine plant fibers and coarse plant fibers, the absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 30-80:20-70.

[0144] In combination with the first and second solutions, in a feasible implementation manner, the aspect ratio of the plant fiber is 8-150.

[0145] In combination with the first and second options, in a feasible embodiment, the plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reeds and cotton.

[0146] The method for preparing plant fibers from natural plants is a conventional method and can be reasonably adjusted based on the characteristics of the natural plants and the properties of the target plant fibers. For example, in some embodiments of the present invention, the preparation method includes removing lignin and most hemicellulose from the natural plants, followed by bleaching or unbleaching to obtain a fibrous material primarily composed of cellulose, i.e., the plant fibers.

[0147] In combination with the first and second schemes, in a feasible embodiment, the fibrous material can be a single fiber, a combination of multiple fibers, or a combination of fibers with different diameters or widths, and / or different aspect ratios. Preferably, the fibrous material includes a combination of two or more fibers with different diameters or widths, and / or different aspect ratios.

[0148] In combination with the first and second solutions, in a feasible embodiment, the absolute dry mass ratio of the plant fiber to the hydrophilically modified chemical synthetic fiber is 98-70:2-30, preferably 95-80:5-20.

[0149] The porous powder material used in the present invention has an acoustic enhancement function and can be selected from porous powder materials commonly used in the art for preparing acoustic enhancement materials. Combining the first and second embodiments, in one feasible embodiment, the porous powder material includes one or a combination of zeolite molecular sieves, activated silica, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, aluminum oxide, hydrogel, and aerogel.

[0150] Combining the first and second solutions, in a feasible embodiment, the zeolite molecular sieve has a particle size of 0.5-10 μm, including micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

[0151] Combining the first and second options, in a feasible embodiment, the zeolite molecular sieve includes one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve and MTT structure molecular sieve.

[0152] In combination with the first and second solutions, in a feasible implementation manner, the precipitation aid includes one or a combination of polyacrylamide, starch, polyethyleneimine, polyimide and guar gum.

[0153] Combining the first and second solutions, in a feasible embodiment, the gram weight range of the acoustic enhancement composite material is 50-1200 g / m 2 .

[0154] Combining the first and second embodiments, in one feasible embodiment, the acoustically enhanced composite material can be in the form of a sheet, block, or irregular shape. When applying this acoustically enhanced composite material, those skilled in the art can reasonably select an acoustically enhanced composite material of an appropriate shape as needed. Alternatively, those skilled in the art can combine the preparation method provided herein with conventional methods to obtain an acoustically enhanced composite material of a desired shape.

[0155] In combination with the first embodiment, the present invention provides a third embodiment. In the third embodiment, the acoustic enhancement composite material is formed by interwoven fibrous materials, having a three-dimensional network structure inside, and a porous powder material is attached (precipitated) on the surface of the fibrous material by a precipitation aid.

[0156] The fibrous material comprises one or a combination of inorganic fibers, plant fibers, and chemical fibers of composite components. The acoustic enhancement composite material provided by the third embodiment of the present invention is more fluffy and has a high porosity, which is conducive to the acoustic effect of the porous powder material.

[0157] In the present invention, fibrous materials are interwoven with each other to form an acoustically enhanced composite material, and a three-dimensional network structure is formed inside the acoustically enhanced composite material during the interweaving process; since the surface of the fibrous material is attached to the porous powder material through a precipitation aid, it is equivalent to the porous powder material also being attached to the three-dimensional network structure and the surface of the acoustically enhanced composite material.

[0158] In combination with the first and third options, in a feasible embodiment, based on the total weight of the acoustic enhancement composite material as 100%, the absolute dry mass proportion of the fibrous material is 19.50-85.95%, the absolute dry mass proportion of the porous powder material is 14.0-80.0%, preferably 50.0-70.0%, and the absolute dry mass proportion of the precipitation aid is 0.05-0.5%.

[0159] In combination with the first and third solutions, in one feasible embodiment, the diameter or width of the fibrous material is in the range of 3-70 μm, and the aspect ratio is in the range of 8-500. In the present invention, "aspect ratio" refers to the ratio of the length to the diameter of the fibrous material. In some special fibrous materials, "aspect ratio" can also be understood as the ratio of its length to width.

[0160] In combination with the first and third solutions, in a feasible implementation manner, the diameter or width of the inorganic fiber is in the range of 3-45 μm, and the aspect ratio is 10-500.

[0161] In combination with the first and third options, in a feasible implementation manner, the inorganic fiber includes one or a combination of basalt fiber, glass fiber, quartz fiber, asbestos fiber, volcanic rock fiber, metal fiber, alumina fiber and carbon fiber.

[0162] The inorganic fibers used in the present invention are characterized by their low or no absorption of water and their resistance to deformation in aqueous environments. Their stiffness, rigidity, and resistance to deformation make them crucial for maintaining the shape and stiffness of acoustically enhanced composite materials.

[0163] In combination with the first and third solutions, in a feasible implementation manner, the diameter or width of the plant fiber is in the range of 8-70 μm, and the aspect ratio is in the range of 8-150.

[0164] In combination with the first and third solutions, in a feasible implementation manner, the moisture absorption ratio of the plant fiber is 16.0-31.5%, preferably 20.0-31.5%.

[0165] In combination with the first and third options, in a feasible embodiment, the plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reeds and cotton.

[0166] The plant fibers selected in the present invention contain a large number of hydrophilic groups, such as hydroxyl groups, carboxyl groups, etc. When the acoustic enhancement composite material containing the plant fibers is actually used in the back cavity, water molecules in the air will be preferentially absorbed and fixed by the plant fibers, thereby reducing the performance attenuation of the porous powder material caused by water molecules, and fully improving the service life of the acoustic enhancement composite material in the back cavity.

[0167] The plant fibers used in this invention are primarily composed of cellulose, along with minimal amounts of hemicellulose and lignin. To improve the acoustic performance of acoustically enhanced composite materials, increasing the mass percentage of the porous powder material with acoustic enhancement capabilities within the composite material is a primary approach. The porous powder particles used in this invention are inorganic and significantly smaller than the fibrous material, resulting in no significant interaction between the two in an aqueous system.

[0168] To address this issue, the present invention adds a small amount of a precipitation aid. This inherently sticky agent can secure the porous powder material particles to the surface of the fibrous material through adhesion, effectively securing the porous powder material particles within the three-dimensional network structure within the acoustically enhanced composite material. However, under external forces (such as continuous vibration and collision), the porous powder material particles risk falling from the surface of the acoustically enhanced composite material, a phenomenon known as powder shedding.

[0169] Therefore, it is of great significance to increase the specific surface area of ​​plant fibers and improve the binding sites between plant fibers and porous powder material particles. The surface binding sites of some plant fibers meet the requirements, but the surfaces of some plant fibers are relatively smooth and dense, and they need to use certain physical and chemical methods, such as grinding and hammering, to destroy the primary wall on the surface of the plant fibers without destroying the aspect ratio of the plant fibers, or with very little damage to the aspect ratio, and disperse the fiber bundles into single fibers, thereby significantly increasing the specific surface area of ​​the plant fibers and exposing more hydrophilic groups. The increase in the specific surface area of ​​plant fibers not only improves the binding sites between them and the particles of porous powder materials, reducing the risk of powder loss in acoustically enhanced composite materials, but also improves the bonding strength between fibers, thereby improving the internal bonding strength of acoustically enhanced composite materials.

[0170] Because the distribution of fine fibers, roughness, and specific surface area of ​​the plant fibers used in this invention are difficult to measure, the present invention indirectly uses the "moisture absorption ratio" as a comprehensive indicator for evaluating the specific surface area of ​​the plant fibers. The more individual fibers are dispersed on the surface of the plant fiber, the greater the specific surface area and the greater the water-binding capacity.

[0171] In the present invention, the "moisture absorption ratio" of plant fiber is measured according to the following method:

[0172] Weigh a certain mass (about 2.0 g) of plant fiber and add it to pure water at 20°C. Adjust the absolute dry mass concentration of the plant fiber to about 0.5%, and then perform shear dispersion to disperse the plant fiber into single fibers.

[0173] After the plant fibers are completely dispersed into single fibers, the plant fiber dispersion is filtered through a 200-mesh sieve. Under the action of natural gravity, the water that has not interacted with the plant fibers will be lost. After standing for 10 minutes, the wet plant fibers are collected and weighed, denoted as X, where X includes the absolute dry mass of the plant fibers and the mass of the water absorbed by them.

[0174] Transfer the wet plant fiber with a mass of X to a 110°C oven and dry it to constant weight. Record the mass at this point as Y, where Y is the absolute dry mass of the plant fiber and the mass of pure water absorbed by the wet plant fiber with a mass of X as Z, where Z = XY.

[0175] The moisture absorption ratio of plant fiber was calculated according to the following formula 1;

[0176] Moisture absorption ratio = (Z / Y) × 100% Formula 1.

[0177] For the same type of plant fiber, the greater the moisture absorption ratio, the stronger its ability to absorb water, which means that its specific surface area is larger and more fine fibers are exposed on the surface. This helps reduce the risk of powder loss in the three-dimensional network structure of acoustically enhanced composite materials and improves the internal bonding strength of the material.

[0178] The method for preparing plant fibers from natural plants is a conventional method and can be reasonably adjusted based on the characteristics of the natural plants and the properties of the target plant fibers. For example, in some embodiments of the present invention, the preparation method includes removing lignin and most hemicellulose from the natural plants, followed by bleaching or unbleaching to obtain a fibrous material primarily composed of cellulose, i.e., the plant fibers.

[0179] In combination with the first and third solutions, in a feasible embodiment, the fibrous material may be a combination of fibrous materials with different diameters or widths and different aspect ratios;

[0180] Preferably, the fibrous material is selected from a combination of two or more fibrous materials having different diameters or widths and different aspect ratios.

[0181] In combination with the first and third solutions, in a feasible embodiment, the diameter or width of the chemical fiber of the composite component is in the range of 10-70 μm, and the aspect ratio is in the range of 10-200.

[0182] In combination with the first and third options, in a feasible implementation manner, the chemical fiber of the composite component includes one or a combination of chemical fibers of composite components such as a sheath-core structure, a parallel structure, and an island-in-the-sea structure.

[0183] In combination with the first and third options, in a feasible embodiment, the chemical fiber of the skin-core structure composite component includes a core layer and a skin layer covering the core layer, and the material of the skin layer includes chemical fiber with a melting point not higher than 140°C, and the material of the core layer includes chemical fiber with a melting point not lower than 150°C.

[0184] In combination with the first and third solutions, in a feasible embodiment, the core layer includes ordinary polyester fibers and / or polypropylene fibers, and the skin layer includes polyethylene fibers and / or modified polyester fibers.

[0185] In some embodiments of the present invention, the chemical fiber of the composite component may be a chemical fiber with a core layer of ordinary polyester fiber and a sheath layer of polyethylene fiber, a chemical fiber with a core layer of polypropylene fiber and a sheath layer of polyethylene fiber, or a chemical fiber with a core layer of ordinary polyester fiber and a sheath layer of modified polyester fiber, etc.

[0186] The melting point of the common polyester fiber is 250-265°C, the melting point of the polyethylene fiber is 110-130°C, the melting point of the polypropylene fiber is 150-170°C, and the melting point of the modified polyester fiber is lower, 100-140°C.

[0187] Under conditions where the temperature is not lower than the melting point of the sheath contained in the chemical fiber of the composite component, the sheath of the chemical fiber of the composite component begins to melt. After melting, it can bond with other fibers or porous powder material particles with which it comes into contact. At this time, the core layer does not melt and maintains the original structure and morphology of the chemical fiber of the composite component. Therefore, the rational use of the chemical fiber of the composite component can significantly improve the internal bonding strength of the acoustic enhancement composite material and reduce the risk of powder loss. At the same time, because the core layer fiber does not melt, the chemical fiber of the composite component will not shrink significantly, thereby not reducing the thickness of the acoustic enhancement composite material, and will not change the shape and fluffiness of the acoustic enhancement composite material.

[0188] In combination with the first and third solutions, in a feasible embodiment, the chemical fibers of the parallel structure composite component include chemical fibers with a melting point not higher than 140°C and chemical fibers with a melting point not lower than 150°C.

[0189] Combining the first and third options, in one feasible embodiment, the chemical fiber having a melting point no higher than 140°C includes polyethylene fiber and / or modified polyester fiber, and the chemical fiber having a melting point no lower than 150°C includes ordinary polyester fiber and / or polypropylene fiber. The ordinary polyester fiber has a melting point of 250-265°C, the polyethylene fiber has a melting point of 110-130°C, the polypropylene fiber has a melting point of 150-170°C, and the modified polyester fiber has a lower melting point of 100-140°C.

[0190] The chemical fiber with a sea-island structure composite component used in the present invention, i.e., the sea-island fiber, is a polymer dispersed in another polymer. The dispersed phase is in an "island" state in the fiber cross section, and the matrix is ​​equivalent to the "sea". From the cross section of the sea-island fiber, one component is surrounded by another component in a fine and dispersed state, as if there are many islands in the sea.

[0191] Combining the first and third solutions, in a feasible embodiment, the matrix material of the chemical fiber of the island-in-sea structure composite component includes chemical fibers having a melting point not higher than 140°C, and the dispersed phase material includes chemical fibers having a melting point not lower than 150°C;

[0192] Preferably, the material of the matrix includes polyethylene fiber and / or modified polyester fiber, etc., and the material of the dispersed phase includes ordinary polyester fiber and / or polypropylene fiber, etc.

[0193] When the operating temperature of the chemical fibers of the parallel structure composite components and the chemical fibers of the island structure composite components is between the melting points of the two chemical components with different melting points they contain, the chemical fibers with low melting points melt and play a bonding role, while the chemical fibers with high melting points do not melt and maintain the structure and morphology of the composite component fibers. Therefore, through the synergistic effect of the two chemical components with different melting points, the internal bonding strength of the acoustic enhancement composite material can be significantly improved, the risk of powder loss can be reduced, and the thickness of the acoustic enhancement composite material will not be reduced, nor will the morphology and fluffy state of the acoustic enhancement composite material be changed.

[0194] The chemical fibers of the sheath-core structure composite component, the chemical fibers of the parallel structure composite component (i.e., parallel composite fibers), and the chemical fibers of the sea-island structure composite component (i.e., sea-island fibers) used in the present invention are all existing conventional products and can be purchased commercially.

[0195] In combination with the first and third solutions, in a feasible implementation manner, the absolute dry mass ratio of the plant fiber to the chemical fiber of the composite component is 98-60:2-40.

[0196] The porous powder material used in the present invention has an acoustic enhancement function and can be selected from porous powder materials commonly used in the art for preparing acoustic enhancement materials. Combining the first and third options, in one feasible embodiment, the porous powder material includes one or a combination of zeolite molecular sieves, activated silica, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, aluminum oxide, hydrogel, aerogel, and the like.

[0197] In combination with the first and third options, in a feasible embodiment, the zeolite molecular sieve has a particle size of 0.5-10 μm, including micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

[0198] In order to enhance the acoustic enhancement effect of the acoustic enhancement composite material to a greater extent, in combination with the first and third schemes, in a feasible embodiment, the zeolite molecular sieve includes one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve and MTT structure molecular sieve.

[0199] In combination with the first and third solutions, in a feasible implementation manner, the precipitation aid includes one or a combination of polyacrylamide, starch, polyethyleneimine, polyimide and guar gum.

[0200] In combination with the first and third solutions, in a feasible embodiment, the gram weight range of the acoustic enhancement composite material is 50-1200 g / m 2 .

[0201] Combining the first and third options, in one feasible embodiment, the acoustically enhanced composite material can be in the form of a sheet, block, or irregular shape. When applying this acoustically enhanced composite material, those skilled in the art can select an acoustically enhanced composite material of a suitable shape as needed. Alternatively, those skilled in the art can combine the preparation method provided herein with conventional methods to obtain an acoustically enhanced composite material of a desired shape.

[0202] The acoustically enhanced composite material provided by the third embodiment of the present invention has high strength. After a drop test, the surface of the acoustically enhanced composite material does not fall off, and it is firmly bonded to the double-sided adhesive, and there is no internal separation of the acoustically enhanced composite material. This is an important condition for ensuring the long-term and stable operation of the acoustically enhanced composite material in the speaker cavity.

[0203] In a second aspect, the present invention provides a method for preparing the acoustically enhanced composite material, wherein the method comprises:

[0204] Step 1: Dispersing the fibrous material, the porous powder material and the precipitation aid in water respectively to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0205] Step 2: adding the porous powder material dispersion to the fibrous material dispersion and mixing them evenly, then adding the precipitation aid dispersion and mixing them evenly, so that the fibrous materials are interwoven with each other and the porous powder material is precipitated on the surface of the fibrous material;

[0206] Step 3: Filter the mixed solution obtained in step 2 to obtain a precursor material;

[0207] Step 4: Drying the precursor material to obtain an acoustically enhanced composite material.

[0208] In conjunction with the second aspect, in a feasible embodiment, when the fibrous material includes chemical fibers of a composite component, the manufacturing method further includes:

[0209] Step 5: The acoustic enhancement material is subjected to a high-temperature treatment at a temperature not lower than the melting point of the sheath layer of the composite chemical fiber component, so that the sheath layer of the composite chemical fiber component melts while the core layer does not melt. The melted sheath layer acts as a bonding agent. After the heat preservation is completed, the material is cooled to room temperature to obtain a high-strength and high-efficiency acoustic enhancement material. The temperature of the high-temperature treatment needs to be selected based on the melting point of the sheath layer. In one feasible embodiment, the high-temperature treatment can be carried out in a forced air drying oven at a temperature of 110-145°C, preferably 130-145°C, for 5-20 minutes.

[0210] The present invention prepares an acoustically enhanced composite material through an integrated molding method, wherein integrated molding refers to a process in which fibrous materials with porous powder materials attached to the surface are interwoven to form a three-dimensional network structure during the molding process of the acoustically enhanced composite material, which can also be called co-molding.

[0211] In combination with the second aspect, in a feasible embodiment, in step 1, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 0.2-4%, preferably 0.5-4%.

[0212] In combination with the second aspect, in a feasible embodiment, in step 1, based on the total weight of the porous powder material dispersion being 100%, the absolute dry mass concentration of the porous powder material is 1-50%.

[0213] In combination with the second aspect, in a feasible embodiment, in step 1, based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.01-4.00%.

[0214] In combination with the second aspect, in a feasible implementation manner, in step 1, the water includes a mixture of one or more of deionized water, distilled water, and reverse osmosis water.

[0215] In conjunction with the second aspect, in one feasible embodiment, in step 2, in order to achieve faster and better mixing, this step is performed under stirring conditions. In step 2, the interweaving of the fibrous material and the precipitation of the porous powder material on the surface of the fibrous material are performed simultaneously.

[0216] In conjunction with the second aspect, in one feasible embodiment, in step three, the mixed solution obtained in step two is filtered to initially remove water from the mixed solution, and the resulting material may have a water content of 10-80 wt%. During the filtration process, water is directly filtered through the filter, while the fibrous material with the porous powder material deposited on its surface gradually accumulates, interweaving the fibrous material to form a three-dimensional network structure.

[0217] The filtration in step 3 is a conventional operation and can be adjusted according to the actual working conditions on site. For example, in some embodiments of the present invention, the filtration is suction filtration.

[0218] The present invention allows the shape of the resulting acoustically enhanced composite material to be controlled through the filtration operation in step three. If multiple filtrations are performed in step three, the thickness of the stacked material increases, resulting in a block-shaped acoustically enhanced composite material. In other words, the present invention allows the thickness of the acoustically enhanced composite material to be controlled through filtration. Alternatively, molds of different shapes can be used for filtration as needed to obtain irregularly shaped acoustically enhanced composite materials. Of course, the dried block-shaped or irregularly shaped acoustically enhanced composite material can also be cut to obtain irregularly shaped acoustically enhanced composite materials.

[0219] In conjunction with the second aspect, in one feasible embodiment, in step 4, the drying is a conventional operation that can be adjusted based on actual on-site conditions, as long as the moisture in the precursor material is removed. For example, in some embodiments of the present invention, the drying is performed using a vacuum freeze dryer or a forced air drying oven.

[0220] In a water-based system, there is no interaction between the porous powder material with acoustic enhancement function and the fibrous material. Therefore, a precipitation aid is used in the preparation of the acoustic enhancement composite material. This precipitation aid has its own viscosity and adhesion, which can precipitate the particles of the porous powder material on the surface of the fibrous material.

[0221] In a third aspect, the present invention also provides 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 loudspeaker back cavity, wherein the loudspeaker back cavity is equipped with the acoustically enhanced composite material described above.

[0222] In a fourth aspect, the present invention further provides an electronic device, wherein the above-mentioned acoustic enhancement composite material is installed in the rear cavity of the speaker of the electronic device.

[0223] In combination with the fourth aspect, in a feasible implementation, the electronic device includes a smart phone, TWS earphones, headphones, smart glasses, smart watches, VR devices, AR devices, tablet computers or thin and light laptops, etc.

[0224] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0225] 1. Efficient mass production: The present invention can efficiently mass-produce acoustic enhancement composite materials without the need for special equipment, special raw materials, or chemicals.

[0226] 2. Arbitrary cutting: The acoustic enhancement composite material can be cut into the required shape according to the size and dimensions of the speaker's rear cavity and filled into the speaker's rear cavity.

[0227] 3. High efficiency in acoustic performance: The acoustically enhanced composite material provided by the present invention has high efficiency in acoustic performance. For a unit mass of porous powder material with acoustic enhancement function, its acoustic performance is better than that of commonly used acoustic enhancement particles on the market.

[0228] 4. The acoustically enhanced composite material provided by the present invention has stable acoustic properties. After being stored at high temperature and high humidity in accordance with the technical content recorded in Section 7.8.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022), its acoustic performance is not lost at all. BRIEF DESCRIPTION OF THE DRAWINGS

[0229] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0230] FIG1 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 1 of the present invention.

[0231] FIG2 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 3 of the present invention.

[0232] FIG3 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 4 of the present invention.

[0233] FIG4 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 6 of the present invention.

[0234] FIG5 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 7 of the present invention.

[0235] FIG6 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 8 of the present invention.

[0236] FIG7 is a SEM image of the sheet-like acoustic enhancement composite material provided in Example 2 of the present invention.

[0237] FIG8 is a schematic diagram showing the morphology of the hydroxyl-containing coniferous wood fiber used in Example 10 of the present invention.

[0238] FIG9 is a schematic diagram showing the morphology of coniferous wood fibers used in Example 12 of the present invention.

[0239] FIG10 is a schematic diagram showing the morphology of the hardwood fiber used in Example 12 of the present invention.

[0240] FIG11 is a schematic diagram showing the morphology of coniferous wood fibers used in Example 13 of the present invention.

[0241] FIG12 is a schematic diagram showing the morphology of the hardwood fiber used in Example 13 of the present invention.

[0242] FIG13 is a schematic diagram showing the morphology of the softwood fiber used in Comparative Example 11.

[0243] FIG14 is a schematic diagram showing the morphology of the softwood fiber used in Comparative Example 14.

[0244] FIG15 is a schematic diagram showing the morphology of the hardwood fiber used in Comparative Example 14.

[0245] FIG16 is a SEM image of the sheet-like acoustic enhancement material provided in Example 10 of the present invention.

[0246] FIG17 shows the surface morphology of the sheet-like acoustic enhancement material provided in Example 14 of the present invention after the drop test in Test Example 7 of the present invention.

[0247] FIG18 shows the surface morphology of the sheet-like acoustic enhancement material provided in Comparative Example 14 after the drop test in Test Example 7 of the present invention.

[0248] FIG19 is a SEM image of the sheet-like acoustic enhancement composite material provided in Example 1 of the present invention.

[0249] FIG20 is an SEM image of the sheet-like acoustically enhanced composite material provided in Example 7 of the present invention.

[0250] FIG21 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 16 of the present invention.

[0251] FIG22 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 17 of the present invention.

[0252] FIG23 shows the surface morphology of the sheet-like acoustic enhancement composite material obtained in Example 18 of the present invention.

[0253] FIG24 is an SEM image of the sheet-like acoustically enhanced composite material obtained in Example 17 of the present invention. DETAILED DESCRIPTION

[0254] It should be noted that the term "comprise" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatus.

[0255] The "range" disclosed in the present invention is given in the form of a lower limit and an upper limit. It 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 boundaries of a particular range. All ranges defined in this way are combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, a range of 60-120 and 80-110 is listed for a particular parameter, and it is understood that a range of 60-110 and 80-120 is 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 can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0256] In the present invention, unless otherwise specified, the numerical range "ab" is an abbreviation for any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" are listed in this invention, and "0-5" is merely an abbreviation for these numerical combinations.

[0257] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0258] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0259] In the present invention, unless otherwise specified, the term "two" used in this specification means "at least two".

[0260] In the present invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method comprising steps (a) and (b) indicates that the method may comprise steps (a) and (b) performed sequentially, or may comprise steps (b) and (a) performed sequentially. For example, the method further comprising step (c) indicates that step (c) may be added to the method in any order, for example, the method may comprise steps (a), (b) and (c), or may comprise steps (a), (c) and (b), or may comprise steps (c), (a) and (b), etc.

[0261] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below in conjunction with the attached table, drawings and examples. The following 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 regarded as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0262] In the embodiment, the "moisture absorption ratio" of the plant fiber is measured according to the following method:

[0263] Weigh a certain mass (about 2.0 g) of plant fiber and add it to pure water at 20°C. Adjust the absolute dry mass concentration of the plant fiber to about 0.5%, and then perform shear dispersion to disperse the plant fiber into single fibers.

[0264] After the plant fibers are completely dispersed into single fibers, the plant fiber dispersion is filtered through a 200-mesh sieve. Under the action of natural gravity, the water that has not interacted with the plant fibers will be lost. After standing for 10 minutes, the wet plant fibers are collected and weighed, denoted as X, where X includes the absolute dry mass of the plant fibers and the mass of the water absorbed by them.

[0265] Transfer the wet plant fiber with a mass of X to a 110°C oven and dry it to constant weight. Record the mass at this point as Y, where Y is the absolute dry mass of the plant fiber and the mass of pure water absorbed by the wet plant fiber with a mass of X as Z, where Z = XY.

[0266] The moisture absorption ratio of plant fiber was calculated according to the following formula 1;

[0267] Moisture absorption ratio = (Z / Y) × 100% Formula 1.

[0268] In the embodiment, the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material can be measured by the following method:

[0269] After drying the sheet-like acoustic enhancement composite material in an oven at 110°C to constant weight, its mass is accurately weighed and recorded as A;

[0270] Accurately weigh the mass of the dried crucible, denoted as B, and place the acoustically enhanced composite sheet with a mass of A into the dried crucible. The crucible is then placed in a high-temperature muffle furnace and set to a heating program of increasing the temperature from room temperature to 525°C at a heating rate of 0.5°C / min, holding the temperature for 120 minutes, and then cooling to room temperature.

[0271] Weigh the total weight of the crucible and the porous powder material with acoustic enhancement function in the crucible, recorded as C;

[0272] After the sheet-like acoustic enhancement composite material with a mass of A is calcined at high temperature, the mass of the porous powder material with acoustic enhancement function contained therein is recorded as D, then D = CB;

[0273] In the sheet-like acoustic enhancement composite material with a mass of A, the mass percentage of the porous powder material having an acoustic enhancement function is recorded as E, and then E=(D / A)×100% (Formula 2).

[0274] The strength of sheet-like acoustic enhancement composite materials is one of the important indicators for evaluating sheet-like acoustic enhancement composite materials and is also an important guarantee for the application stability of sheet-like acoustic enhancement composite materials. In the test examples of the present invention, the strength of the sheet-like acoustic enhancement composite materials was measured according to the following method:

[0275] Cut the acoustic enhancement composite material into a certain size (e.g., 10*10mm square) and stick it to the inner wall of a metal test fixture with double-sided tape. The metal test fixture is a rectangular parallelepiped with a mass of 220g.

[0276] The height of the automatic drop tester was adjusted to 180 cm, the floor was marble, and the metal test tooling with the sheet-like acoustic enhancement composite material was automatically dropped from a height of 180 cm onto the marble floor.

[0277] All six sides of the metal test fixture need to undergo drop testing. For example, if each side undergoes six drop tests, the total number of drop tests is 36. In some special cases, each side requires 12 drop tests, for a total of 72 drop tests.

[0278] After the drop test, observe the surface of the sheet-like acoustic enhancement composite material to see if ① the porous powder material with acoustic enhancement function falls off, and ② the sheet-like acoustic enhancement composite material undergoes internal separation and shedding.

[0279] Among them, ① is used to evaluate the bonding strength between the porous powder material and the three-dimensional network structure in the sheet-like acoustically enhanced composite material. After the drop test, if no falling of the porous powder material is observed, it indicates that the bonding strength between the porous powder material and the three-dimensional network structure in the sheet-like acoustically enhanced composite material is high.

[0280] ② Used to evaluate the internal bond strength of sheet-like acoustic reinforcement composite materials. Due to the thickness and mass of sheet-like acoustic reinforcement composite materials, they may separate after a drop test due to insufficient internal bond strength. If no separation or fall-off is observed after the drop test, it indicates that the internal bond strength is high.

[0281] Example 1

[0282] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0283] Wherein, the fibrous material is 100% coarse plant fiber, and the coarse plant fiber is a coniferous wood fiber containing hydroxyl groups with an average width of 45 μm and an aspect ratio of 70;

[0284] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0285] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0286] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 19.50%, the absolute dry mass of the porous powder material accounts for 80.0%, and the absolute dry mass of the precipitation aid accounts for 0.5%;

[0287] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0288] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0289] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0290] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0291] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0292] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0293] Example 2

[0294] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0295] The fibrous material is composed of coarse plant fibers and fine plant fibers, wherein the coarse plant fibers are hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 29.60%; the fine plant fibers are hydroxyl-containing broadleaf wood fibers with an average width of 17 μm and an aspect ratio of 65, and the absolute dry mass accounts for 10%;

[0296] In fibrous materials, the absolute dry mass ratio of coarse plant fibers to fine plant fibers is 74.7:25.3;

[0297] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0298] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0299] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 39.60%, the absolute dry mass of the porous powder material accounts for 60.0%, and the absolute dry mass of the precipitation aid accounts for 0.4%;

[0300] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0301] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0302] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0303] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0304] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0305] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0306] Example 2-1

[0307] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0308] The fibrous material is composed of coarse plant fibers and fine plant fibers, wherein the coarse plant fibers are hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70, accounting for 12.7% of the absolute dry mass; the fine plant fibers are hydroxyl-containing broadleaf wood fibers with an average width of 17 μm and an aspect ratio of 65, accounting for 26.9% of the absolute dry mass;

[0309] In fibrous materials, the absolute dry mass ratio of coarse plant fibers to fine plant fibers is 32.1:67.9;

[0310] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0311] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0312] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 39.60%, the absolute dry mass of the porous powder material accounts for 60.0%, and the absolute dry mass of the precipitation aid accounts for 0.4%;

[0313] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0314] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0315] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0316] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0317] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0318] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0319] Example 3

[0320] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0321] The fibrous material is composed of coarse plant fibers, fine plant fibers and regenerated cellulose fibers, wherein the coarse plant fibers are hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 30%; the fine plant fibers are hydroxyl-containing broadleaf wood fibers with an average width of 17 μm and an aspect ratio of 65, and the absolute dry mass accounts for 30%; the regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, and the absolute dry mass accounts for 4.25%;

[0322] In the fibrous material, the absolute dry mass ratio of plant fiber to regenerated cellulose fiber is 93.4:6.6;

[0323] The precipitation aid is guar gum with an average relative molecular weight of 1.6 million;

[0324] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0325] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 64.25%, the absolute dry mass of the porous powder material accounts for 35.5%, and the absolute dry mass of the precipitation aid accounts for 0.25%;

[0326] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0327] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0328] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0329] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0330] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0331] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0332] Example 4

[0333] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0334] The fibrous material is composed of coarse plant fibers, fine plant fibers, regenerated cellulose fibers and chemical synthetic fibers. The coarse plant fibers are coniferous wood fibers containing hydroxyl groups with an average width of 45 μm and an aspect ratio of 70, and their absolute dry mass accounts for 48.5%; the fine plant fibers are broadleaf wood fibers containing hydroxyl groups with an average width of 17 μm and an aspect ratio of 65, and their absolute dry mass accounts for 30%; the regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, and their absolute dry mass accounts for 3.0%; the chemical synthetic fibers are maleic anhydride-modified polyester fibers with an average diameter of 15 μm and an aspect ratio of 100, and their absolute dry mass accounts for 4.45%;

[0335] In the sheet-like acoustic enhancement composite material, the plant fibers include coarse plant fibers and fine coarse plant fibers, totaling 78.5%;

[0336] Among all fibrous materials, the absolute dry mass ratio of plant fiber, regenerated cellulose fiber and chemical synthetic fiber is 91.33:3.49:5.18;

[0337] Among all fibrous materials, hydrophilic natural fibers include coarse plant fibers, fine coarse plant fibers and viscose fibers. The absolute dry mass ratio of hydrophilic natural fibers to chemical synthetic fibers is 94.82:5.18.

[0338] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0339] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0340] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 85.95%, the absolute dry mass of the porous powder material accounts for 14.0%, and the absolute dry mass of the precipitation aid accounts for 0.05%;

[0341] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0342] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0343] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0344] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0345] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0346] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0347] Example 4-1

[0348] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0349] The fibrous material is composed of coarse plant fibers, fine plant fibers, regenerated cellulose fibers and bacterial fibers. The coarse plant fibers are coniferous wood fibers containing hydroxyl groups with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 48.5%; the fine plant fibers are broadleaf wood fibers containing hydroxyl groups with an average width of 17 μm and an aspect ratio of 65, and the absolute dry mass accounts for 24.75%; the regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, and the absolute dry mass accounts for 8.5%; the bacterial fibers are bacterial fibers produced by Acetobacter with an average diameter of 10 μm and an aspect ratio of 100, and the absolute dry mass accounts for 4.2%;

[0350] In the sheet-like acoustic enhancement composite material, the plant fibers include coarse plant fibers and fine coarse plant fibers, totaling 73.25%;

[0351] Among all fibrous materials, the absolute dry mass ratio of plant fiber, regenerated cellulose fiber and bacterial fiber is 85.2:9.9:4.9;

[0352] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0353] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0354] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 85.95%, the absolute dry mass of the porous powder material accounts for 14.0%, and the absolute dry mass of the precipitation aid accounts for 0.05%;

[0355] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0356] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0357] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0358] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0359] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0360] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0361] Example 4-2

[0362] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0363] The fibrous material is composed of coarse plant fibers, fine plant fibers, regenerated cellulose fibers and bacterial fibers. The coarse plant fibers are coniferous wood fibers containing hydroxyl groups with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 48.5%; the fine plant fibers are broadleaf wood fibers containing hydroxyl groups with an average width of 17 μm and an aspect ratio of 65, and the absolute dry mass accounts for 35.05%; the regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, and the absolute dry mass accounts for 1.6%; the bacterial fibers are bacterial fibers produced by Acetobacter with an average diameter of 10 μm and an aspect ratio of 100, and the absolute dry mass accounts for 0.8%;

[0364] In the sheet-like acoustic enhancement composite material, the plant fibers include coarse plant fibers and fine coarse plant fibers, totaling 83.55%;

[0365] Among all fibrous materials, the absolute dry mass ratio of plant fiber, regenerated cellulose fiber and bacterial fiber is 97.2:1.9:0.9;

[0366] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0367] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0368] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 85.95%, the absolute dry mass of the porous powder material accounts for 14.0%, and the absolute dry mass of the precipitation aid accounts for 0.05%;

[0369] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0370] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0371] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0372] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0373] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0374] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0375] Example 5

[0376] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0377] The fibrous material is composed of fine plant fibers, which are hydroxyl-containing broadleaf wood fibers with an average width of 17 μm and an aspect ratio of 65, and an absolute dry mass ratio of 81.32%;

[0378] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0379] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.6 μm, including micropores with a pore size of 0.54 nm and mesopores with a pore size of 25 nm;

[0380] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 81.32%, the absolute dry mass of the porous powder material accounts for 18.62%, and the absolute dry mass of the precipitation aid accounts for 0.06%;

[0381] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0382] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0383] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0384] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0385] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0386] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0387] Example 6

[0388] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0389] The fibrous material is a hydrophilically modified chemical synthetic fiber, which is a maleic anhydride-modified polyester fiber with an average width of 15 μm and an aspect ratio of 100, and an absolute dry mass of 19.50%.

[0390] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0391] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0392] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 19.50%, the absolute dry mass of the porous powder material accounts for 80.0%, and the absolute dry mass of the precipitation aid accounts for 0.5%;

[0393] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0394] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0395] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0396] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0397] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0398] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0399] Example 7

[0400] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0401] The fibrous material is composed of hydrophilically modified chemical synthetic fibers, wherein the hydrophilically modified chemical synthetic fibers are maleic anhydride-modified polypropylene fibers with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 39.60%;

[0402] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0403] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0404] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 39.60%, the absolute dry mass of the porous powder material accounts for 60.0%, and the absolute dry mass of the precipitation aid accounts for 0.4%;

[0405] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0406] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0407] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0408] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0409] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0410] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0411] Example 8

[0412] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0413] The fibrous material is composed of hydrophilically modified chemical synthetic fibers and original chemical synthetic fibers, that is, chemical synthetic fibers that have not been hydrophilically modified, wherein the hydrophilically modified chemical synthetic fibers are maleic anhydride-modified polyester fibers with an average width of 15 μm and an aspect ratio of 100, and their absolute dry mass accounts for 44.25%; the original chemical synthetic fibers are ordinary polyester fibers that have not been modified with maleic anhydride and have an average width of 15 μm and an aspect ratio of 100, and their absolute dry mass accounts for 20.00%;

[0414] The absolute dry mass ratio of the hydrophilically modified chemical synthetic fiber to the original chemical synthetic fiber is 68.9:31.1;

[0415] The precipitation aid is guar gum with an average relative molecular weight of 1.6 million;

[0416] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0417] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 64.25%, the absolute dry mass of the porous powder material accounts for 35.5%, and the absolute dry mass of the precipitation aid accounts for 0.25%;

[0418] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0419] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0420] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0421] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0422] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0423] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0424] Comparative Example 1

[0425] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 1 only in that:

[0426] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 14.0%, the absolute dry mass of the porous powder material accounts for 85.0%, and the absolute dry mass of the precipitation aid accounts for 1.0%.

[0427] Comparative Example 2

[0428] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 4 only in that:

[0429] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 90.95%, the absolute dry mass of the porous powder material accounts for 9.0%, and the absolute dry mass of the precipitation aid accounts for 0.05%.

[0430] Among them, the fibrous material is composed of coarse plant fibers, fine plant fibers, regenerated cellulose fibers and chemical synthetic fibers. The coarse plant fibers are coniferous wood fibers containing hydroxyl groups with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 48.5%; the fine plant fibers are broadleaf wood fibers containing hydroxyl groups with an average width of 17 μm and an aspect ratio of 65, and the absolute dry mass accounts for 35%; the regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, and the absolute dry mass accounts for 3.0%; the chemical synthetic fibers are maleic anhydride-modified polyester fibers with an average diameter of 15 μm and an aspect ratio of 100, and the absolute dry mass accounts for 4.45%.

[0431] Comparative Example 3

[0432] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 1 only in that:

[0433] The hydrophilic fibers are 100% coarse plant fibers, which are coniferous wood fibers containing hydroxyl groups and have an average width of 45 μm and an aspect ratio of 7.5.

[0434] Comparative Example 4

[0435] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 5 only in that:

[0436] The hydrophilic fibers are composed of fine plant fibers, which are broadleaf wood fibers containing hydroxyl groups and have an average width of 17 μm and an aspect ratio of 5:10.

[0437] Comparative Example 5

[0438] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 2 only in that:

[0439] The hydrophilic fibers are composed of coarse plant fibers and fine plant fibers, wherein the coarse plant fibers are coniferous wood fibers containing hydroxyl groups with an average width of 45 μm and an aspect ratio of 70, and their absolute dry mass accounts for 25.3%; the fine plant fibers are broadleaf wood fibers containing hydroxyl groups with an average width of 17 μm and an aspect ratio of 65, and their absolute dry mass accounts for 74.7%.

[0440] Comparative Example 6

[0441] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 6 only in that:

[0442] The fibrous material is composed of original chemical synthetic fibers, wherein the original chemical synthetic fibers are ordinary polyester fibers that have not been modified with maleic anhydride and have an average width of 15 μm and an aspect ratio of 100, and their absolute dry mass accounts for 19.50%.

[0443] Comparative Example 7

[0444] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 7 only in that:

[0445] The fibrous material is composed of original chemical synthetic fibers, wherein the original chemical synthetic fibers are ordinary polypropylene fibers that have not been modified with maleic anhydride and have an average width of 45 μm and an aspect ratio of 70, and their absolute dry mass accounts for 39.60%.

[0446] Comparative Example 8

[0447] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 6 only in that:

[0448] The hydrophilically modified chemical synthetic fiber is a maleic anhydride-modified polypropylene fiber with an average width of 15 μm and an aspect ratio of 7.5.

[0449] Comparative Example 9

[0450] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 6 only in that:

[0451] The hydrophilically modified chemical synthetic fiber is a maleic anhydride-modified polypropylene fiber with an average width of 15 μm and an aspect ratio of 5:10.

[0452] Test Example 1

[0453] In this test example, the sheet-like acoustically enhanced composite materials provided in Examples 1 to 8 and Comparative Examples 1 to 9 were first cut into a size of 10*10 mm and weighed. Then, the resonance frequency offset value Δf0 of the sheet-like acoustically enhanced composite materials was tested in accordance with Section 7.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 1 below.

[0454] Table 1 Acoustic performance data of sheet-like acoustically enhanced composite materials of Examples 1 to 8 and Comparative Examples 1 to 9

[0455] After calculation, the sheet-like acoustically enhanced composite materials obtained in Examples 1 to 8 and Comparative Examples 1 to 9 were cut into a size of 10*10 mm, and the absolute dry mass of the molecular sieve in each sheet-like acoustically enhanced composite material was 40.0 mg, 30.0 mg, 17.75 mg, 7.0 mg, 9.31 mg, 40.0 mg, 30.0 mg, 17.75 mg, 42.5 mg, 4.5 mg, 40.0 mg, 9.31 mg, 30.0 mg, 40.0 mg, 30.0 mg, 40.0 mg and 40.0 mg respectively.

[0456] The acoustic efficiency of the sheet-like acoustically enhanced composite material per unit mass is calculated according to the formula shown below. The obtained acoustic efficiency data are shown in Table 2 below.

[0457] Acoustic efficiency = Δf0 / (absolute dry mass of molecular sieve), unit: Hz / mg.

[0458] Table 2 Acoustic efficiency data of sheet-like acoustically enhanced composite materials of Examples 1 to 8 and Comparative Examples 1 to 9

[0459] It can be seen from the experimental data in Table 1 and Table 2 above that the sheet-like acoustically enhanced composite materials provided in Examples 1 to 8 of the present invention all have high-efficiency acoustic performance.

[0460] It can also be seen from the experimental data in Tables 1 and 2 above that, compared with Example 1 of the present invention which only uses coarse plant fibers as fibrous materials, Example 2 uses a combination of coarse plant fibers and fine plant fibers, Example 3 uses a combination of coarse plant fibers, fine plant fibers and regenerated cellulose fibers, and Example 4 uses a combination of coarse plant fibers, fine plant fibers, regenerated cellulose fibers and chemical synthetic fibers as fibrous materials, the acoustic efficiencies of the sheet-like acoustically enhanced composite materials provided by Examples 2 to 4 increase successively, and are all better than the sheet-like acoustically enhanced composite materials provided by Example 1.

[0461] It can also be seen from the experimental data in Tables 1 and 2 above that in the sheet-like acoustically enhanced composite material provided in Comparative Example 1, the absolute dry mass of the molecular sieve accounts for 85.0%, which is higher than 80.0% of Example 1, but its acoustic performance and acoustic efficiency are lower than those of Example 1. The reason is that the acoustic material must have a rich porous structure in order to fully exert its acoustic performance, and in the sheet-like acoustically enhanced composite material, the fibrous materials are interwoven to form a three-dimensional network structure, and the richness of this structure determines the performance of the acoustic performance of the material. Since the absolute dry mass of the molecular sieve in Comparative Example 1 accounts for 85%, in order to enable the molecular sieve to be completely precipitated in the network structure of the fibrous material, the absolute dry mass of the precipitation aid accounts for 1%, and therefore the absolute dry mass of the fibrous material accounts for 14.0%. Therefore, for the three-dimensional network structure of the sheet-like acoustically enhanced composite material of Comparative Example 1, its porous structure is far less rich than that of Example 1, and therefore the acoustic performance of the molecular sieve cannot be fully exerted.

[0462] Similarly, in the sheet-like acoustic enhancement composite material provided in Comparative Example 2, the absolute dry mass of the molecular sieve accounts for 9%. Due to the small absolute dry mass of the molecular sieve, the acoustic performance of the sheet-like acoustic enhancement composite material is very limited and has no significance in practical applications. At the same time, due to the small absolute dry mass of the molecular sieve and the unchanged amount of precipitation aid, the acoustic performance of the molecular sieve will also be negatively affected. In summary, the acoustic performance and acoustic efficiency of the sheet-like acoustic enhancement composite material provided in Comparative Example 2 are also significantly worse than those of Example 4.

[0463] It can also be seen from the experimental data in Tables 1 and 2 above that, compared with the sheet-like acoustically enhanced composite material provided in Example 1 of the present invention, the aspect ratio of the coarse plant fibers in the sheet-like acoustically enhanced composite material provided in Comparative Example 3 is only 7.5, that is, the coarse plant fibers are too short, and the three-dimensional network structure constructed therefrom is not ideal, and the pores are insufficient, resulting in the acoustic performance and acoustic efficiency of the sheet-like acoustically enhanced composite material provided in Comparative Example 3 being significantly worse than those in Example 1, and the acoustic performance is significantly reduced.

[0464] It can also be seen from the experimental data in Tables 1 and 2 above that, compared with the sheet-like acoustically enhanced composite material provided in Example 5 of the present invention, the aspect ratio of the fine plant fibers in the sheet-like acoustically enhanced composite material provided in Comparative Example 4 is as high as 510, that is, the fine plant fibers are too long, resulting in the fine plant fibers being interwoven with each other and not easily dispersed, thereby causing uneven dispersion of the fibers in the powder sheet and affecting the performance of the powder sheet.

[0465] It can also be seen from the experimental data in Tables 1 and 2 above that, compared with the sheet-like acoustic enhancement composite material provided in Example 2 of the present invention, the absolute dry mass ratio of coarse plant fibers and fine plant fibers in the sheet-like acoustic enhancement composite material provided in Comparative Example 5 is not within the numerical range of 100-30:0-70. Since the fine plant fibers have a small width and their specific surface area is larger than that of the coarse fibers, the porous powder particles precipitated on their surface will be much higher than that of the coarse fibers, resulting in uneven distribution of the porous powder particles in the sheet-like acoustic enhancement composite material, and thus its acoustic performance is slightly worse than that of Example 2.

[0466] It can also be seen from the experimental data in Tables 1 and 2 above that the acoustic properties of the sheet-like acoustically enhanced composite materials obtained in Example 6 and Comparative Example 6, and in Example 7 and Comparative Example 7 are the same, which shows that the use of hydrophilically modified chemical synthetic fibers does not affect the acoustic properties of the sheet-like acoustically enhanced composite materials.

[0467] It can also be seen from the experimental data in Tables 1 and 2 above that the acoustic performance of the sheet-like acoustically enhanced composite material provided in Comparative Example 8 is inferior to the acoustic performance of the sheet-like acoustically enhanced composite material provided in Example 6. This is because: the aspect ratio of the hydrophilic modified chemical synthetic fiber is only 7.5, which is not in the range of 8-500, that is, the hydrophilic modified chemical synthetic fiber is too short, and the three-dimensional network structure it constructs is not ideal, and the porosity is insufficient, resulting in the acoustic performance and acoustic efficiency of the sheet-like acoustically enhanced composite material provided in Comparative Example 8 being significantly worse than those in Example 6, and the acoustic performance is significantly reduced.

[0468] It can also be seen from the experimental data in Tables 1 and 2 above that the acoustic performance of the sheet-like acoustically enhanced composite material provided by Comparative Example 9 is inferior to the acoustic performance of the sheet-like acoustically enhanced composite material provided by Example 6. This is because: the aspect ratio of the hydrophilic modified chemical synthetic fiber is as high as 510, which is not in the range of 8-500, that is, the hydrophilic modified chemical synthetic fiber is too long, resulting in the hydrophilic modified chemical synthetic fibers being interwoven with each other and not easy to disperse, thereby causing uneven dispersion of the fibers in the powder sheet, affecting the performance of the powder sheet, resulting in the acoustic performance and acoustic efficiency of the sheet-like acoustically enhanced composite material provided by Comparative Example 9 being significantly worse than those of Example 6, and the acoustic performance is significantly reduced.

[0469] Test Example 2

[0470] In this test example, the sheet-like acoustically enhanced composite materials provided in Examples 1 to 8 and Comparative Examples 1 to 9 were first cut into a size of 10*10 mm, and then the sheet-like acoustically enhanced composite materials were tested for high-temperature and high-humidity storage Δf'HTHR in accordance with the technical content described in Section 7.8.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 3 below.

[0471] Table 3 High temperature and high humidity storage Δf' HTHR test data of sheet-like acoustic enhancement composite materials provided by Examples 1 to 8 and Comparative Examples 1 to 9

[0472] As can be seen from Table 3 above, compared with the corresponding comparative examples, the acoustic performance of the sheet-like acoustic enhancement composite materials provided by Examples 1 to 5 of the present invention is not reduced after high temperature and high humidity treatment, indicating that these sheet-like acoustic enhancement composite materials all have stable performance. In addition, the acoustic performance of the sheet-like acoustic enhancement composite materials provided by Comparative Examples 1 to 5 is not significantly reduced after high temperature and high humidity treatment, indicating that these sheet-like acoustic enhancement composite materials also have stable performance, but their acoustic performance (acoustic performance in Table 1 and acoustic efficiency in Table 2) are not as good as those of the corresponding examples. In addition, since maleic anhydride-modified polypropylene fiber is used in Comparative Examples 8 and 9, the acoustic performance of the sheet-like acoustic enhancement composite materials obtained therefrom is not significantly reduced after high temperature and high humidity treatment, indicating that these sheet-like acoustic enhancement composite materials also have stable performance, but their acoustic performance (acoustic performance in Table 1 and acoustic efficiency in Table 2) are not as good as those of the corresponding examples.

[0473] Table 3 also shows that the acoustic performance of the sheet-like acoustic-enhancing composite materials provided in Examples 6-8 of the present invention did not degrade after high-temperature, high-humidity treatment, indicating that these sheet-like acoustic-enhancing composite materials also possess stable performance. However, the acoustic performance of the sheet-like acoustic-enhancing composite materials provided in Comparative Examples 6 and 7 significantly degraded after high-temperature, high-humidity treatment, demonstrating the significant role of the hydrophilically modified synthetic fiber in enhancing the high-temperature, high-humidity storage Δf'HTHR of the sheet-like acoustic-enhancing composite materials.

[0474] Test Example 3

[0475] In this test example, a high-definition digital microscope was used to obtain the surface morphology of the sheet-like acoustic enhancement composite material provided in Example 1, Example 3-Example 4, and Example 6-Example 8 of the present invention, and the experimental results are shown in Figures 1 to 6, respectively. It can be clearly seen from Figures 1 to 6 that the sheet-like acoustic enhancement composite material provided by the embodiment of the present invention has a three-dimensional network structure in which fibrous materials are interwoven with each other, and the porous powder material particles are precipitated on the surface of the fibrous material and in the three-dimensional network structure by the action of the precipitation aid. At the same time, it can also be seen from Figures 1 to 6 that the surface of the sheet-like acoustic enhancement composite material provided by the embodiment of the present invention has a rich porous structure; and the higher the absolute dry mass ratio of the porous powder material particles in the sheet-like acoustic enhancement composite material, the more obvious the porous powder material particles attached thereto by the precipitation aid that can be observed in the three-dimensional network structure.

[0476] Test Example 4

[0477] This test example subjected the sheet-like acoustic-enhancing composite materials provided in Examples 1-2 and 7 of the present invention to SEM analysis. The resulting SEM images are shown in Figures 19, 7, and 20. As can be seen from Figures 19, 7, and 20, the sheet-like acoustic-enhancing composite materials provided in Examples 1-2 and 7 of the present invention contain a large number of porous structures with high porosity. These porous structures are three-dimensional networks formed by interwoven fibrous materials. Based on this, it is reasonable to infer that the sheet-like acoustic-enhancing composite materials prepared in the other examples of the present invention also contain a large number of porous structures with high porosity.

[0478] Example 9

[0479] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 800g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0480] The fibrous material is composed of plant fibers and chemical fibers of a composite component, wherein the plant fibers are hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70, with an absolute dry mass ratio of 14.55% and a moisture absorption ratio of 29.5%;

[0481] The chemical fiber of the composite component is a chemical fiber of a sheath-core structure composite component (Ningbo Dafa Chemical Fiber Co., Ltd., model VF-450LM), including a core layer and a sheath layer covering the core layer, wherein the core layer is ordinary polyester fiber (melting point 250-265°C), and the sheath layer is modified polyester fiber (melting point 110°C). The diameter of the chemical fiber of the composite component is 50 μm, and it is shortened to an aspect ratio of 40, and the absolute dry mass accounts for 5.0%;

[0482] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0483] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0484] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 19.55%, the absolute dry mass of the porous powder material accounts for 80.0%, and the absolute dry mass of the precipitation aid accounts for 0.45%;

[0485] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0486] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0487] The absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 2.0%, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 20%, and the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.02%.

[0488] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0489] Step 3: Filtering the mixed solution obtained in step 2 to obtain a sheet material having a water content of 70 wt%;

[0490] Step 4: performing blast drying on the sheet material, wherein the blast drying temperature is 110° C. and the drying time is 120 min, and after the drying is completed, a sheet-like acoustic enhancement composite material is obtained;

[0491] Step 5: Place the sheet-like acoustic enhancement composite material described above into a blast drying oven, and ensure that the temperature in the blast drying oven is 140°C, and keep it warm for 8 minutes to perform high-temperature treatment on the sheet-like acoustic enhancement composite material, so that the skin layer of the chemical fiber of the composite component melts while the core layer does not melt. After the skin layer melts, it plays a bonding role. After the insulation is completed, the sheet-like acoustic enhancement composite material is cooled to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic enhancement composite material; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic enhancement composite material is measured by the method shown above, and it is compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0492] Example 10

[0493] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 800g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0494] The fibrous material is composed of plant fibers and chemical fibers of a composite component, wherein the plant fibers are hydroxyl-containing coniferous wood fibers having an average width of 36 μm and an aspect ratio of 70, an absolute dry mass ratio of 29.60%, and a moisture absorption ratio of 22.5%. The morphology of the hydroxyl-containing coniferous wood fibers is shown in FIG8 , as can be seen from FIG8 , the surfaces of the hydroxyl-containing coniferous wood fibers used in this embodiment all have a large number of fine fibers.

[0495] The chemical fiber of the composite component is a chemical fiber of a sheath-core structure composite component (Ningbo Dafa Chemical Fiber Co., Ltd., model VF-450LM), including a core layer and a sheath layer covering the core layer, wherein the core layer is ordinary polyester fiber (melting point 250-265°C), and the sheath layer is modified polyester fiber (melting point 110°C). The diameter of the chemical fiber of the composite component is 50 μm, and it is shortened to an aspect ratio of 40, and the absolute dry mass accounts for 10.0%;

[0496] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0497] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0498] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 39.60%, the absolute dry mass of the porous powder material accounts for 60.0%, and the absolute dry mass of the precipitation aid accounts for 0.40%;

[0499] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0500] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0501] The absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 2.0%, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 20%, and the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.02%.

[0502] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0503] Step 3: Filtering the mixed solution obtained in step 2 to obtain a sheet material having a water content of 70 wt%;

[0504] Step 4: performing blast drying on the sheet material, wherein the blast drying temperature is 110° C. and the drying time is 120 min, and after the drying is completed, a sheet-like acoustic enhancement composite material is obtained;

[0505] Step 5: Place the sheet-like acoustic enhancement composite material described above into a blast drying oven, and ensure that the temperature in the blast drying oven is 140°C, and keep it warm for 8 minutes to perform high-temperature treatment on the sheet-like acoustic enhancement composite material, so that the skin layer of the chemical fiber of the composite component melts while the core layer does not melt. After the skin layer melts, it plays a bonding role. After the insulation is completed, the sheet-like acoustic enhancement composite material is cooled to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic enhancement composite material; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic enhancement composite material is measured by the method shown above, and it is compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0506] Example 11

[0507] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 800g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0508] The fibrous material is composed of an organic fibrous material and an inorganic fibrous material, wherein the organic fibrous material is composed of plant fibers and chemical fibers of a composite component, and the plant fibers are hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70, with an absolute dry mass ratio of 40% and a moisture absorption ratio of 22.5%;

[0509] The chemical fiber of the composite component is a chemical fiber of a parallel structure composite component, including a high-melting point fiber and a low-melting point fiber, wherein the high-melting point fiber is an ordinary polyester fiber (melting point of 250-265°C), and the low-melting point fiber is a polyethylene fiber (melting point of 120°C). The diameter of the chemical fiber of the composite component is 50 μm, and it is shortened to an aspect ratio of 40, and the absolute dry mass accounts for 18.0%;

[0510] The inorganic fibrous material is glass fiber with an average diameter of 11 μm and an aspect ratio of 280, and its absolute dry mass accounts for 1.65%;

[0511] The precipitation aid is guar gum with an average relative molecular weight of 1.6 million;

[0512] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0513] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 59.65%, the absolute dry mass of the porous powder material accounts for 40.0%, and the absolute dry mass of the precipitation aid accounts for 0.35%;

[0514] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0515] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0516] The absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 2.0%, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 20%, and the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.02%.

[0517] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0518] Step 3: Filtering the mixed solution obtained in step 2 to obtain a sheet material having a water content of 70 wt%;

[0519] Step 4: performing blast drying on the sheet material, wherein the blast drying temperature is 110° C. and the drying time is 120 min, and after the drying is completed, a sheet-like acoustic enhancement composite material is obtained;

[0520] Step 5: Place the sheet-like acoustic enhancement composite material described above into a blast drying oven, and ensure that the temperature in the blast drying oven is 140°C, and keep it warm for 8 minutes to perform high-temperature treatment on the sheet-like acoustic enhancement composite material, so that the skin layer of the chemical fiber of the composite component melts while the core layer does not melt. After the skin layer melts, it plays a bonding role. After the insulation is completed, the sheet-like acoustic enhancement composite material is cooled to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic enhancement composite material; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic enhancement composite material is measured by the method shown above, and it is compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0521] Example 12

[0522] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 800g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0523] The fibrous material is composed of 100% organic fibrous material, wherein the absolute dry mass of the hydroxyl-containing softwood fiber having an average width of 45 μm and an aspect ratio of 70 is 21.55% and the moisture absorption ratio is 29.5%, and the absolute dry mass of the hydroxyl-containing hardwood fiber having an average width of 17 μm and an aspect ratio of 65 is 8.0% and the moisture absorption ratio is 27.5%. The morphology of the softwood fiber and the hardwood fiber is shown in Figures 9 and 10. As can be seen from Figures 9 and 10, the surface of the plant fibers used in this embodiment has a large number of fine fibers.

[0524] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0525] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0526] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 29.55%, the absolute dry mass of the porous powder material accounts for 70.0%, and the absolute dry mass of the precipitation aid accounts for 0.45%;

[0527] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0528] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0529] The absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 2.0%, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 20%, and the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.02%.

[0530] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0531] Step 3: Filtering the mixed solution obtained in step 2 to obtain a sheet material having a water content of 70 wt%;

[0532] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the drying time is 120 minutes. After drying, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0533] Example 13

[0534] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 800g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0535] The fibrous material is composed of 100% organic fibrous material, wherein the absolute dry mass of the hydroxyl-containing softwood fiber having an average width of 45 μm and an aspect ratio of 70 is 29.60%, and the moisture absorption ratio is 22.5%; and the absolute dry mass of the hydroxyl-containing hardwood fiber having an average width of 17 μm and an aspect ratio of 65 is 10%, and the moisture absorption ratio is 25.5%. The morphologies of the softwood fiber and the hardwood fiber are shown in FIG11 and FIG12 , respectively. As can be seen from FIG11 and FIG12 , the surfaces of the plant fibers used in this embodiment all have a large number of fine fibers.

[0536] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0537] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0538] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 39.60%, the absolute dry mass of the porous powder material accounts for 60.0%, and the absolute dry mass of the precipitation aid accounts for 0.40%;

[0539] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0540] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0541] The absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 2.0%, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 20%, and the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.02%.

[0542] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0543] Step 3: Filtering the mixed solution obtained in step 2 to obtain a sheet material having a water content of 70 wt%;

[0544] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the drying time is 120 minutes. After drying, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0545] Example 14

[0546] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 800g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0547] The fibrous material is composed of an organic fibrous material and an inorganic fibrous material, wherein the absolute dry mass proportion of hydroxyl-containing coniferous wood fiber with an average width of 45 μm and an aspect ratio of 70 is 30%, and the moisture absorption ratio is 22.5%, the absolute dry mass proportion of hydroxyl-containing broadleaf wood fiber with an average width of 17 μm and an aspect ratio of 65 is 18%, and the moisture absorption ratio is 17.5%; and the absolute dry mass proportion of glass fiber with an average diameter of 11 μm and an aspect ratio of 280 is 1.65%;

[0548] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0549] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0550] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 49.65%, the absolute dry mass of the porous powder material accounts for 50.0%, and the absolute dry mass of the precipitation aid accounts for 0.35%;

[0551] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0552] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0553] The absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 2.0%, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 20%, and the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.02%.

[0554] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0555] Step 3: Filtering the mixed solution obtained in step 2 to obtain a sheet material having a water content of 70 wt%;

[0556] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the drying time is 120 minutes. After drying, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0557] Example 15

[0558] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 800g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0559] The fibrous material is composed of an inorganic fibrous material and a composite chemical fiber, wherein the inorganic fibrous material is a glass fiber with an average diameter of 11 μm and an aspect ratio of 280, and its absolute dry mass accounts for 14.55%;

[0560] The chemical fiber of the composite component is a chemical fiber of a sheath-core structure composite component (Ningbo Dafa Chemical Fiber Co., Ltd., model VF-450LM), including a core layer and a sheath layer covering the core layer, wherein the core layer is ordinary polyester fiber (melting point 250-265°C), and the sheath layer is modified polyester fiber (melting point 110°C). The diameter of the chemical fiber of the composite component is 50 μm, and it is shortened to an aspect ratio of 40, and the absolute dry mass accounts for 5.0%;

[0561] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0562] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0563] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 19.55%, the absolute dry mass of the porous powder material accounts for 80.0%, and the absolute dry mass of the precipitation aid accounts for 0.45%;

[0564] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0565] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0566] The absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 2.0%, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 20%, and the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.02%.

[0567] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0568] Step 3: Filtering the mixed solution obtained in step 2 to obtain a sheet material having a water content of 70 wt%;

[0569] Step 4: performing blast drying on the sheet material, wherein the blast drying temperature is 110° C. and the drying time is 120 min, and after the drying is completed, a sheet-like acoustic enhancement composite material is obtained;

[0570] Step 5: Place the sheet-like acoustic enhancement composite material described above into a blast drying oven, and ensure that the temperature in the blast drying oven is 140°C, and keep it warm for 8 minutes to perform high-temperature treatment on the sheet-like acoustic enhancement composite material, so that the skin layer of the chemical fiber of the composite component melts while the core layer does not melt. After the skin layer melts, it plays a bonding role. After the insulation is completed, the sheet-like acoustic enhancement composite material is cooled to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic enhancement composite material; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic enhancement composite material is measured by the method shown above, and it is compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0571] Comparative Example 10

[0572] This comparative example provides an acoustic enhancement particle, which is a conventional commercial product with an average particle size of 420 μm.

[0573] Comparative Example 11

[0574] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 10 in that:

[0575] The softwood fiber had a moisture absorption ratio of 14.0%, and ordinary polyester fibers were used, rather than composite chemical fibers. The morphology of the softwood fiber is shown in Figure 13 . As can be seen from Figure 13 , the softwood fiber used in this comparative example, with a moisture absorption ratio of 14.0%, had very few surface fine fibers.

[0576] Comparative Example 12

[0577] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 10 in that:

[0578] The moisture absorption ratio of softwood fiber is 14.0%.

[0579] Comparative Example 13

[0580] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 10 in that:

[0581] Use ordinary polyester fiber instead of chemical fiber with composite components.

[0582] Comparative Example 14

[0583] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 13 only in that:

[0584] The moisture absorption ratio of the softwood fiber was 14.0%, and the moisture absorption ratio of the hardwood fiber was 15.0%. The morphologies of the softwood fiber and the hardwood fiber are shown in Figures 14 and 15, respectively. As can be seen from Figures 14 and 15, the plant fiber used in this comparative example has very few fine fibers on its surface.

[0585] Comparative Example 15

[0586] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 13 only in that:

[0587] The moisture absorption ratio of softwood fiber is 32.0%, and that of hardwood fiber is 33.0%.

[0588] Test Example 5

[0589] This test example subjected the sheet-like acoustic-enhancing composite material provided in Example 10 of the present invention to SEM analysis, and the resulting SEM image is shown in Figure 16. As can be seen from Figure 16, the sheet-like acoustic-enhancing composite material provided in Example 10 of the present invention contains a large number of pore structures and a high porosity. These pore structures are three-dimensional networks formed by interwoven fibrous materials. Based on this, it is reasonable to infer that the sheet-like acoustic-enhancing composite materials prepared in the other examples of the present invention also contain a large number of pore structures and a high porosity.

[0590] Test Example 6

[0591] In this test example, the sheet-like acoustically enhanced composite materials provided in Examples 9 to 15 and Comparative Examples 11 to 15 were first cut into a size of 10*10 mm and weighed. Then, the resonance frequency offset value Δf0 of the sheet-like acoustically enhanced composite materials was tested in accordance with Section 7.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 4 below.

[0592] Table 4 Acoustic performance data of sheet-like acoustically enhanced composite materials of Examples 9 to 15 and Comparative Examples 11 to 15

[0593] After calculation, the sheet-like acoustically enhanced composite materials obtained from Examples 9 to 15 and Comparative Examples 11 to 15 were cut into a size of 10*10 mm, and the absolute dry mass of the molecular sieve in each sheet-like acoustically enhanced composite material was 64.0 mg, 48.0 mg, 32.0 mg, 56.0 mg, 48.0 mg, 40.0 mg, 64.0 mg, 48.0 mg, 48.0 mg, 48.0 mg, 48.0 mg and 48.0 mg respectively.

[0594] The acoustic efficiency of the sheet-like acoustically enhanced composite material per unit mass is then calculated according to the formula shown below. The obtained acoustic efficiency data are shown in Table 5 below.

[0595] Acoustic efficiency = Δf0 / (absolute dry mass of molecular sieve), unit: Hz / mg.

[0596] Table 5 Acoustic efficiency data of sheet-like acoustically enhanced composite materials of Examples 9 to 15 and Comparative Examples 11 to 15

[0597] It can be seen from the experimental data in Table 4 and Table 5 above that the sheet-like acoustically enhanced composite materials provided in Examples 9 to 15 of the present invention all have high-efficiency acoustic performance.

[0598] This test example also accurately weighed 64.0 mg, 56.0 mg, 48.0 mg, 40.0 mg and 32.0 mg of the acoustic enhancement particles provided in Comparative Example 10, and tested the resonance frequency offset value Δf0 of the acoustic enhancement particles in accordance with Section 7.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 6 below.

[0599] Table 6 Acoustic performance and acoustic efficiency data of commercially available conventional acoustic enhancement particles

[0600] By comparing the experimental data in Tables 4-5 and 6, it can be seen that the acoustic properties of the sheet-like acoustic enhancement composite materials provided by Examples 9-15 of the present invention are significantly better than the acoustic properties of conventional commercially available acoustic enhancement particles.

[0601] By comparing the experimental data in Tables 4-5 and 6, it can be seen that: compared with Example 10 of the present invention, the acoustic properties of the sheet-like acoustic enhancement composite materials provided by Comparative Examples 11, 12, and 13 are the same. This is mainly because: regardless of whether the chemical fiber or ordinary polyester fiber of the composite component has basically no effect on the acoustic properties of the sheet-like acoustic enhancement composite material. The main difference between the sheet-like acoustic enhancement composite materials provided by these embodiments and the comparative examples is that the sheet-like acoustic enhancement composite material provided by Example 10 of the present invention has a high internal bonding strength; while the internal bonding strength of the sheet-like acoustic enhancement composite materials provided by Comparative Examples 11, 12, and 13 is far less than that of Example 10. For details, please see Table 7 and the relevant explanation of Table 7.

[0602] The sheet-like acoustic-enhancing composite materials provided in Examples 10 and 13 of the present invention have the same absolute dry weight percentage of molecular sieve, 60.0%. However, the acoustic performance of the sheet-like acoustic-enhancing composite material provided in Example 10 is slightly better than that of Example 13 because Example 10 contains 10.0% absolute dry weight percentage of chemical fiber in a sheath-core composite component.

[0603] For the sheet-like acoustic enhancement composite materials provided in Examples 9 and 15 of the present invention, the absolute dry mass percentage of the molecular sieve is the same, both 80%. However, the acoustic performance of the sheet-like acoustic enhancement composite material provided by Example 9 is slightly better than that of Example 15. The reason is that: Example 9 adds coniferous wood fiber with an absolute dry mass percentage of 14.55%, while Example 15 adds glass fiber with an absolute dry mass percentage of 14.55%. As is known to all, the density of glass fiber is much greater than that of coniferous wood fiber. Therefore, the density of the sheet-like acoustic enhancement composite material obtained in Example 15 is also greater than that of the sheet-like acoustic enhancement composite material obtained in Example 9. Accordingly, its acoustic performance is slightly lower than that of the sheet-like acoustic enhancement composite material provided in Example 9.

[0604] For the sheet-like acoustic enhancement composite materials provided in Example 13 of the present invention and Comparative Example 14, the absolute dry mass proportion of the molecular sieve is the same, both of which are 60%. Although the moisture absorption ratio of the coniferous wood fiber used in Comparative Example 14 is only 14.0%, and the moisture absorption ratio of the broadleaf wood fiber is only 15.0%, the acoustic performance of the sheet-like acoustic enhancement composite material provided by Comparative Example 14 and the sheet-like acoustic enhancement composite material provided by Example 13 are basically the same. This is because: when the fibrous material has a relatively small moisture absorption ratio, its specific surface area is also small, which mainly limits the combination of the porous powder material and the fibrous material, thereby reducing the strength of the sheet-like acoustic enhancement composite material (as shown in the experimental data in Test Example 7 below), while having little effect on the acoustic performance of the sheet-like acoustic enhancement composite material.

[0605] The sheet-like acoustic-enhancing composite materials provided in Example 13 and Comparative Example 15 of the present invention had the same absolute dry mass percentage of molecular sieve, 60%. However, because the moisture absorption ratio of the softwood fibers used in Comparative Example 15 was 32.0% and that of the hardwood fibers was 33.0%, the area of ​​interconnection between the fibrous materials used in Comparative Example 15 was too large, resulting in insufficient porosity in the sheet-like acoustic-enhancing composite material, making its acoustic performance far inferior to that of the sheet-like acoustic-enhancing composite material provided in Example 13.

[0606] Test Example 7

[0607] In this test, the acoustic-enhancing composite sheets provided in Example 10, Comparative Example 11, and Example 13 and Comparative Example 14 were cut into 10 x 10 mm squares and affixed to the inner wall of a 220 g metal test fixture using double-sided tape. An automated drop tester was then set to a height of 180 cm and placed on a marble floor. The metal test fixture, with the acoustic-enhancing composite sheet attached, was automatically dropped from a height of 180 cm onto the marble floor. Each of the six sides of the metal test fixture was subjected to the drop test six times, for a total of 36 drops.

[0608] After 36 drop tests, the acoustic-enhancing composite sheets provided in Examples 10 and 13 of the present invention remained intact and adhered to the inner wall of the test fixture. Figure 17 shows an image of the acoustic-enhancing composite sheet provided in Example 13 of the present invention after being dropped (after being torn apart), demonstrating that the acoustic-enhancing composite sheet remained intact and showed no signs of separation.

[0609] After 36 drop tests, the acoustic-enhancing composite sheets provided in Comparative Examples 11 and 14 experienced internal separation, with a portion adhering to the inner wall of the test fixture, exposing the fibrous material and porous powder material within. Figure 18 shows an image of the acoustic-enhancing composite sheet provided in Comparative Example 14 after being torn apart, demonstrating internal separation, indicating insufficient internal bonding strength.

[0610] By comparing the drop test results of the sheet-like acoustic enhancing composite materials provided by Example 10 and Comparative Example 11 and Example 13 and Comparative Example 14 of the present invention, it can be seen that controlling the moisture absorption ratio of the organic fibrous material in the sheet-like acoustic enhancing composite material within the specific numerical range of 16.0-31.5% and using chemical fibers of composite components can significantly improve the strength of the sheet-like acoustic enhancing composite material and ensure that the sheet-like acoustic enhancing composite material can work stably in the speaker cavity for a long time.

[0611] Test Example 8

[0612] In this test example, the sheet-like acoustic enhancing composite materials provided in Example 10 and Comparative Examples 11 to 13 were first cut into 10*10mm squares, and then attached to the inner wall of a metal test tool with a mass of 220g using double-sided tape. The height of the automatic drop tester was then adjusted to 180cm, and the floor was marble. The metal test tool with the sheet-like acoustic enhancing composite material attached was automatically dropped onto the marble floor from a height of 180cm. Among them, the six sides of the metal test tool were dropped the same number of times until all the sheet-like acoustic enhancing composite materials were separated. The total number of drops in which the sheet-like acoustic enhancing composite materials provided in Example 10 and Comparative Examples 11 to 13 were separated is shown in Table 7 below.

[0613] Table 7 Total number of drops in which the sheet-like acoustically enhanced composite materials of Example 10 and Comparative Examples 11-13 separated

[0614] As shown in Table 7, the acoustic-enhancing sheet composite material provided in Example 10 did not completely separate until a total of 120 drops were made. Compared to Example 10, the softwood fiber used in Comparative Example 3 had an unsatisfactory moisture absorption ratio, and Comparative Example 13 used ordinary polyester fiber instead of a composite chemical fiber. Although the total number of drops corresponding to complete separation of the acoustic-enhancing sheet composite materials provided in Comparative Examples 12 and 13 was relatively high, it was significantly lower than that of Example 10. For Comparative Example 11, which used an unsatisfactory moisture absorption ratio of softwood fiber and used ordinary polyester fiber instead of a composite chemical fiber, the acoustic-enhancing sheet composite material provided in Comparative Example 11 only experienced complete separation after a total of 6 drops, significantly lower than that of Comparative Examples 12-13 and Example 10.

[0615] The above experimental results also show that controlling the moisture absorption ratio of the organic fibrous material in the sheet-like acoustic enhancement composite material within a specific numerical range of 16.0-31.5% and using chemical fibers of composite components can significantly improve the strength of the sheet-like acoustic enhancement composite material and ensure that the sheet-like acoustic enhancement composite material can work stably in the speaker cavity for a long time.

[0616] In summary, the acoustically enhanced composite materials provided in Examples 9 to 15 of the present invention have high-efficiency acoustic performance and high strength. After a drop test, the surface of the acoustically enhanced composite material does not fall off, and it is firmly bonded to the double-sided adhesive, and there is no internal separation of the acoustically enhanced composite material. This is an important condition to ensure the long-term and stable operation of the acoustically enhanced composite material in the speaker cavity.

[0617] Comparative Example 16

[0618] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 1 only in that:

[0619] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the hydrophilic fiber accounts for 18%, the absolute dry mass of the porous powder material accounts for 81%, and the absolute dry mass of the precipitation aid accounts for 1%.

[0620] Comparative Example 17

[0621] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 2 only in that:

[0622] The hydrophilic fibers are composed of coarse plant fibers and fine plant fibers, wherein the coarse plant fibers account for 65.03% of the absolute dry mass and the fine plant fibers account for 21.97% of the absolute dry mass; in the hydrophilic fibers, the absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 74.7:25.3;

[0623] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the hydrophilic fiber accounts for 87%, the absolute dry mass of the porous powder material accounts for 12.4%, and the absolute dry mass of the precipitation aid accounts for 0.6%.

[0624] Test Example 9

[0625] In this test example, the sheet-like acoustically enhanced composite materials provided in Examples 1 to 5 and Comparative Examples 3 to 5 and Comparative Examples 16 to 17 were first cut into a size of 10*10 mm and weighed. Then, the resonance frequency offset value Δf0 of the sheet-like acoustically enhanced composite materials was tested in accordance with Section 7.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 8 below.

[0626] Table 8 Acoustic performance data of sheet-like acoustically enhanced composite materials of Examples 1 to 5 and Comparative Examples 3 to 5 and Comparative Examples 16 to 17

[0627] After calculation, the sheet-like acoustically enhanced composite materials obtained from Examples 1 to 5, Comparative Examples 3 to 5, and Comparative Examples 16 to 17 were cut into a size of 10*10 mm, and the absolute dry mass of the molecular sieve in each sheet-like acoustically enhanced composite material was 40.0 mg, 30.0 mg, 17.75 mg, 7.0 mg, 9.31 mg, 40.5 mg, 6.2 mg, 40.0 mg, 9.31 mg and 30.0 mg respectively.

[0628] The acoustic efficiency of the sheet-like acoustically enhanced composite material per unit mass is calculated according to the formula shown below. The obtained acoustic efficiency data are shown in Table 9 below.

[0629] Acoustic efficiency = Δf0 / (absolute dry mass of molecular sieve), unit: Hz / mg.

[0630] Table 9 Acoustic efficiency data of sheet-like acoustically enhanced composite materials of Examples 1 to 5 and Comparative Examples 3 to 5 and Comparative Examples 16 to 17

[0631] It can be seen from the experimental data in Table 8 and Table 9 above that the sheet-like acoustically enhanced composite materials provided in Example 1, Example 2, Example 3, Example 4, and Example 5 of the present invention all have high-efficiency acoustic performance.

[0632] It can also be seen from the experimental data in Tables 8 and 9 above that, compared with Example 1 of the present invention which only uses coarse plant fibers as hydrophilic fibers, Example 2 uses a combination of coarse plant fibers and fine plant fibers, Example 3 uses a combination of coarse plant fibers, fine plant fibers and regenerated cellulose fibers, and Example 4 uses a combination of coarse plant fibers, fine plant fibers, regenerated cellulose fibers and chemical synthetic fibers as hydrophilic fibers, the acoustic efficiencies of the sheet-like acoustic enhancement composite materials provided by Examples 2 to 4 increase successively, and are all better than the sheet-like acoustic enhancement composite materials provided by Example 1.

[0633] It can also be seen from the experimental data in Tables 8 and 9 above that, compared with the sheet-like acoustically enhanced composite material provided in Example 1 of the present invention, the sheet-like acoustically enhanced composite material provided in Comparative Example 16 has a higher absolute dry mass ratio of the porous powder material, resulting in insufficient three-dimensional network structure constructed by hydrophilic fibers and insufficient porosity, thereby significantly reducing its acoustic performance.

[0634] It can also be seen from the experimental data in Tables 8 and 9 above that, compared with the sheet-like acoustically enhanced composite material provided in Example 2 of the present invention, the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material provided in Comparative Example 17 is low. Due to the low absolute dry mass ratio of the molecular sieve, the acoustic performance of the sheet-like acoustically enhanced composite material is very limited and has no meaning in practical applications. At the same time, due to the low absolute dry mass ratio of the molecular sieve and the unreduced amount of the precipitation aid, the acoustic performance of the molecular sieve will also be negatively affected. In summary, the acoustic performance and acoustic efficiency of the sheet-like acoustically enhanced composite material provided in Comparative Example 17 are also significantly worse than those in Example 2.

[0635] It can also be seen from the experimental data in Tables 8 and 9 above that, compared with the sheet-like acoustically enhanced composite material provided in Example 1 of the present invention, the aspect ratio of the coarse plant fibers in the sheet-like acoustically enhanced composite material provided in Comparative Example 3 is only 7.5, that is, the coarse plant fibers are too short, and the three-dimensional network structure constructed therefrom is not ideal, and the pores are insufficient, resulting in the acoustic performance and acoustic efficiency of the sheet-like acoustically enhanced composite material provided in Comparative Example 3 being significantly worse than those in Example 1, and the acoustic performance is significantly reduced.

[0636] It can also be seen from the experimental data in Tables 8 and 9 above that, compared with the sheet-like acoustically enhanced composite material provided in Example 5 of the present invention, the aspect ratio of the fine plant fibers in the sheet-like acoustically enhanced composite material provided in Comparative Example 4 is as high as 510, that is, the fine plant fibers are too long, resulting in the fine plant fibers being interwoven with each other and not easily dispersed, thereby causing uneven dispersion of the fibers in the powder sheet and affecting the performance of the powder sheet.

[0637] It can also be seen from the experimental data in Tables 8 and 9 above that, compared with the sheet-like acoustic enhancement composite material provided in Example 2 of the present invention, the absolute dry mass ratio of coarse plant fibers and fine plant fibers in the sheet-like acoustic enhancement composite material provided in Comparative Example 5 is not within the numerical range of 100-30:0-70, resulting in the acoustic performance of the sheet-like acoustic enhancement composite material provided in Comparative Example 5 being slightly worse than that of the sheet-like acoustic enhancement composite material provided in Example 2. The reason is that coarse plant fibers and fine plant fibers are intertwined to build a three-dimensional network structure. When the ratio of the two is not within this range, since the fine plant fibers are small in width and their specific surface area is larger than that of the coarse fibers, the porous powder particles precipitated on their surface will be much higher than the coarse fibers, resulting in uneven distribution of the porous powder particles in the sheet-like acoustic enhancement material, which makes its acoustic performance slightly worse than that of Example 2.

[0638] Test Example 10

[0639] In this test example, the sheet-like acoustically enhanced composite materials provided in Examples 1 to 5 and Comparative Examples 3 to 5 and Comparative Examples 16 to 17 were first cut into a size of 10*10 mm, and then the sheet-like acoustically enhanced composite materials were tested for high temperature and high humidity storage Δf'HTHR in accordance with the technical content described in Section 7.8.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 10 below.

[0640] Table 10 High temperature and high humidity storage Δf' HTHR test data of sheet-like acoustic enhancement composite materials provided by Examples 1 to 5 and Comparative Examples 3 to 5 and Comparative Examples 16 to 17

[0641] As shown in Table 10 above, compared to the comparative examples, the acoustic performance of the sheet-like acoustic enhancement materials provided in Examples 1, 2, 3, 4, and 5 of the present invention did not decrease after high-temperature, high-humidity treatment, indicating that these sheet-like acoustic enhancement materials all possess stable performance. Furthermore, the acoustic performance of the sheet-like acoustic enhancement composite materials provided in Comparative Examples 3-5 and 16-17 did not significantly decrease after high-temperature, high-humidity treatment, indicating that these sheet-like acoustic enhancement composite materials also possess stable performance. However, their acoustic performance (acoustic performance in Table 8 and acoustic efficiency in Table 9) was inferior to that of the corresponding examples.

[0642] Example 16

[0643] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0644] The fibrous material is composed of hydrophilically modified chemical synthetic fibers and coniferous wood fibers, wherein the hydrophilically modified chemical synthetic fibers are maleic anhydride-modified polyester fibers with an average width of 30 μm and an aspect ratio of 80, and the absolute dry mass accounts for 2.00%; the coniferous wood fibers are hydroxyl-containing coniferous wood fibers (which are coarse plant fibers) with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 17.50%;

[0645] The absolute dry mass ratio of hydrophilically modified chemical synthetic fiber to softwood fiber is 10.3:89.7;

[0646] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0647] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0648] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 19.50%, the absolute dry mass of the porous powder material accounts for 80.0%, and the absolute dry mass of the precipitation aid accounts for 0.5%;

[0649] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0650] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0651] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0652] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0653] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0654] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0655] Example 17

[0656] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0657] The fibrous material is composed of hydrophilically modified chemical synthetic fibers, coniferous wood fibers and broadleaf wood fibers, wherein the hydrophilically modified chemical synthetic fibers are maleic anhydride modified polypropylene fibers with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 3.00%; the coniferous wood fibers are coniferous wood fibers containing hydroxyl groups (which are coarse plant fibers) with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 28.60%; the broadleaf wood fibers are broadleaf wood fibers containing hydroxyl groups (which are fine plant fibers) with an average width of 17 μm and an aspect ratio of 65, and the absolute dry mass accounts for 8.0%;

[0658] The absolute dry mass ratio of hydrophilically modified chemical synthetic fibers and plant fibers is 7.58:92.42;

[0659] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0660] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0661] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 39.60%, the absolute dry mass of the porous powder material accounts for 60.0%, and the absolute dry mass of the precipitation aid accounts for 0.4%;

[0662] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0663] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0664] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0665] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0666] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0667] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0668] Example 18

[0669] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2, formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0670] The fibrous material is composed of hydrophilically modified chemical synthetic fibers and hardwood fibers, wherein the hydrophilically modified chemical synthetic fibers are maleic anhydride-modified polypropylene fibers with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 12.00%; the hardwood fibers are hydroxyl-containing hardwood fibers (fine plant fibers) with an average width of 17 μm and an aspect ratio of 65, and the absolute dry mass accounts for 52.25%;

[0671] The absolute dry mass ratio of hydrophilically modified chemical synthetic fiber and hardwood fiber is 18.7:81.3;

[0672] The precipitation aid is guar gum with an average relative molecular weight of 1.6 million;

[0673] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0674] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 64.25%, the absolute dry mass of the porous powder material accounts for 35.5%, and the absolute dry mass of the precipitation aid accounts for 0.25%;

[0675] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0676] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0677] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0678] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0679] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0680] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0681] Example 19

[0682] This embodiment provides a sheet-like acoustic enhancement composite material with a gram weight of 500g / m 2 , formed by interweaving fibrous materials, the sheet-like acoustic enhancement composite material has a three-dimensional network structure inside, and the surface of the fibrous material is attached with a porous powder material through a precipitation aid;

[0683] The fibrous material is composed of hydrophilically modified chemical synthetic fibers and coniferous wood fibers, wherein the hydrophilically modified chemical synthetic fibers are maleic anhydride-modified polyester fibers with an average width of 30 μm and an aspect ratio of 80, and the absolute dry mass accounts for 0.39%; the coniferous wood fibers are hydroxyl-containing coniferous wood fibers (which are coarse plant fibers) with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 19.11%;

[0684] The absolute dry mass ratio of the hydrophilically modified chemical synthetic fiber to the softwood fiber is 2.0:98.0;

[0685] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0686] The porous powder material is ZSM-5 molecular sieve, which has an average particle size of 1.5 μm, including micropores with a pore size of 0.55 nm and mesopores with a pore size of 20 nm;

[0687] Based on the total weight of the sheet-like acoustic enhancement composite material being 100%, the absolute dry mass of the fibrous material accounts for 19.50%, the absolute dry mass of the porous powder material accounts for 80.0%, and the absolute dry mass of the precipitation aid accounts for 0.5%;

[0688] In this embodiment, the sheet-like acoustic enhancement composite material is prepared by a manufacturing method comprising the following specific steps:

[0689] Step 1: Dispersing the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion;

[0690] Wherein, based on the total weight of the fibrous material dispersion as 100%, the absolute dry mass concentration of the fibrous material is 2.0%, based on the total weight of the porous powder material dispersion as 100%, the absolute dry mass concentration of the porous powder material is 20%, and based on the total weight of the precipitation aid dispersion as 100%, the absolute dry mass concentration of the precipitation aid is 0.02%;

[0691] Step 2: Under stirring conditions, the porous powder material dispersion is added to the fibrous material dispersion and mixed evenly, and then the precipitation aid dispersion is added and mixed evenly, so that the fibrous materials are intertwined and the porous powder material is precipitated on the surface of the fibrous material;

[0692] Step 3: Filter the mixed solution obtained in step 2 to obtain a sheet material, wherein the water content of the sheet material is 70 wt%;

[0693] Step 4: The sheet material is then subjected to air drying, wherein the air drying temperature is 110°C and the time is 120 minutes. After the air drying is completed, a sheet-like acoustically enhanced composite material is obtained; the absolute dry mass ratio of the porous powder material in the sheet-like acoustically enhanced composite material is measured by the method shown above, and it is compared with the amount of the porous powder material in the formula. The comparison results show that the two are consistent.

[0694] Comparative Example 18

[0695] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 16 only in that:

[0696] The fibrous material is composed only of coniferous wood fibers, which are hydroxyl-containing coniferous wood fibers (coarse plant fibers) with an average width of 45 μm and an aspect ratio of 70, and the absolute dry mass accounts for 19.50%;

[0697] Comparative Example 19

[0698] This comparative example provides a sheet-like acoustic enhancement composite material, which differs from Example 17 only in that:

[0699] The fibrous material is composed of original unhydrophilically modified chemical synthetic fibers, coniferous wood fibers, and broadleaf wood fibers, wherein the original unhydrophilically modified chemical synthetic fibers are polypropylene fibers with an average width of 45 μm and an aspect ratio of 70, and their absolute dry mass accounts for 3.00%; the coniferous wood fibers are coniferous wood fibers (which are coarse plant fibers) with an average width of 45 μm and an aspect ratio of 70, and their absolute dry mass accounts for 28.60%; the broadleaf wood fibers are broadleaf wood fibers (which are fine plant fibers) with an average width of 17 μm and an aspect ratio of 65, and their absolute dry mass accounts for 8.0%;

[0700] The absolute dry mass ratio of the original chemical synthetic fiber and plant fiber without hydrophilic modification is 7.58:92.42.

[0701] Test Example 11

[0702] In this test example, the sheet-like acoustically enhanced composite materials provided in Examples 16-18 and Comparative Examples 18-19 were first cut into a size of 10*10 mm and weighed. Then, the resonance frequency offset value Δf0 of the sheet-like acoustically enhanced composite materials was tested in accordance with Section 7.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 11 below.

[0703] Table 11 Acoustic performance data of sheet-like acoustically enhanced composite materials of Examples 16 to 18 and Comparative Examples 18 to 19

[0704] After calculation, the sheet-like acoustically enhanced composite materials obtained from Examples 16 to 18 and Comparative Examples 18 to 19 were cut into a size of 10*10 mm, and the absolute dry mass of the molecular sieve in each sheet-like acoustically enhanced composite material was 40.0 mg, 30.0 mg, 17.75 mg, 40.0 mg and 30.0 mg respectively.

[0705] The acoustic efficiency of the sheet-like acoustically enhanced composite material per unit mass is then calculated according to the formula shown below. The obtained acoustic efficiency data are shown in Table 12 below.

[0706] Acoustic efficiency = Δf0 / (absolute dry mass of molecular sieve), unit: Hz / mg.

[0707] Table 12 Acoustic efficiency data of sheet-like acoustically enhanced composite materials of Examples 16 to 18 and Comparative Examples 18 to 19

[0708] It can be seen from the experimental data in Table 11 and Table 12 above that the sheet-like acoustically enhanced composite materials provided in Examples 16 to 18 of the present invention all have high-efficiency acoustic performance.

[0709] It can also be seen from the experimental data in Tables 11 and 12 above that the acoustic properties of the sheet-like acoustic-enhanced composite materials obtained in Examples 16 and 17 are slightly better than the acoustic properties of the sheet-like acoustic-enhanced composite materials provided in the corresponding Comparative Examples 18 and 19. This is because: the fibrous material used in Example 16 is composed of hydrophilically modified chemical synthetic fibers and coniferous wood fibers. Although the chemical fibers have been hydrophilically modified, they still retain the characteristics of chemical fibers being stiff and not easily deformed. Therefore, the sheet-like acoustic-enhanced composite material obtained in Example 16 is fluffier and has a richer pore structure, thereby having better acoustic properties. Since Comparative Example 19 uses the original chemical synthetic fibers that have not been hydrophilically modified, their compatibility with plant fibers is not as good as that of the hydrophilically modified chemical synthetic fibers. Therefore, the acoustic properties of the sheet-like acoustic-enhanced composite material obtained in Comparative Example 19 are not as good as the acoustic properties of the sheet-like acoustic-enhanced composite material provided in Example 17.

[0710] Test Example 12

[0711] In this test example, the sheet-like acoustically enhanced composite materials provided in Examples 16-18 and Comparative Examples 18-19 were first cut into a size of 10*10 mm, and then the sheet-like acoustically enhanced composite materials were tested for high-temperature and high-humidity storage Δf'HTHR in accordance with the technical content described in Section 7.8.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 13 below.

[0712] Table 13 High temperature and high humidity storage Δf' HTHR test data of the sheet-like acoustic enhancement composite materials provided by Examples 16 to 18 and Comparative Examples 18 to 19

[0713] As shown in Table 13, the acoustic performance of the sheet-like acoustic-enhancing composite materials provided in Examples 16-18 and Comparative Examples 18-19 of the present invention did not degrade after high-temperature, high-humidity treatment, indicating that these sheet-like acoustic-enhancing composite materials exhibited stable performance. However, the acoustic performance of the sheet-like acoustic-enhancing composite materials provided in Comparative Examples 18-19 (acoustic performance in Table 11 and acoustic efficiency in Table 12) was inferior to that of the corresponding examples.

[0714] Test Example 13

[0715] In this test example, a high-definition digital microscope was used to obtain the surface morphology of the sheet-like acoustic enhancement composite material provided in Example 16 to Example 18 of the present invention, and the experimental results were shown in Figures 21 to 23, respectively. It can be clearly seen from Figures 21 to 23 that there is a three-dimensional network structure in which fibrous materials are interwoven with each other in the sheet-like acoustic enhancement composite material provided in Example 16 to Example 18 of the present invention, and the porous powder material particles are precipitated on the surface of the fibrous material and in the three-dimensional network structure by the action of the precipitation aid. At the same time, it can also be seen from Figures 21 to 23 that there is a rich porous structure on the surface of the sheet-like acoustic enhancement composite material provided in Example 16 to Example 18 of the present invention; and the higher the absolute dry mass ratio of the porous powder material particles in the sheet-like acoustic enhancement composite material, the more obvious the porous powder material particles attached thereto by the precipitation aid that can be observed in the three-dimensional network structure.

[0716] Test Example 14

[0717] This test example subjected the sheet-like acoustic-enhancing composite material provided in Example 17 of the present invention to SEM analysis, and the resulting SEM image is shown in Figure 24. Figure 24 shows that the sheet-like acoustic-enhancing composite material provided in Example 17 of the present invention contains a large number of porous structures and a high porosity. These porous structures are three-dimensional networks formed by interwoven fibrous materials. Based on this, it is reasonable to infer that the sheet-like acoustic-enhancing composite materials prepared in the other examples of the present invention also contain a large number of porous structures and a high porosity.

[0718] Comparative test example 1

[0719] In this comparative test example, 40.0 mg, 30.0 mg, 17.75 mg, 7.0 mg and 9.31 mg of existing commercially available acoustic enhancement particles (average particle size of 420 μm) were accurately weighed respectively, and then the acoustic performance Δf0 and high temperature and high humidity storage Δf'HTHR of the existing commercially available acoustic enhancement particles were tested according to the same test methods as Test Example 1 and Test Example 2. The results are shown in Table 14 below.

[0720] Table 14 Test results of existing commercially available acoustic enhancement particles

[0721] By comparing the experimental data in Table 1, Table 3, Table 4, Table 6, Table 8, Table 10, Table 11, Table 13 and Table 14, it can be seen that the acoustic performance Δf0 and high temperature and high humidity storage Δf'HTHR of the sheet-like acoustic enhancement composite materials provided by Examples 1 to 18 of the present invention are significantly better than those of the existing commercially available acoustic enhancement particles.

[0722] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, substitutions of equivalent components, or equivalent changes and modifications made within the scope of patent protection, should still fall within the scope of this patent. Furthermore, the technical features of this invention may be freely combined with one another, with other technical inventions, and with other technical inventions.

Claims

1. An acoustically enhanced composite material, characterized in that: The acoustic enhancement composite material is formed by interweaving fibrous materials, and has a three-dimensional network structure inside. The surface of the fibrous material is attached with porous powder material through a precipitation aid.

2. The acoustic enhancement composite material according to claim 1, characterized in that: Based on the total weight of the acoustic enhancement composite material as 100%, the absolute dry mass of the fibrous material accounts for 19.50-85.95%, the absolute dry mass of the porous powder material accounts for 14.0-80.0%, preferably 50.0-70.0%, and the absolute dry mass of the precipitation aid accounts for 0.05-0.5%.

3. The acoustic enhancement composite material according to claim 1, characterized in that: The diameter or width of the fibrous material is in the range of 3-70 μm, and the aspect ratio is in the range of 8-500.

4. The acoustic enhancement composite material according to claim 3, characterized in that: The diameter or width of the fibrous material is in the range of 8-70 μm.

5. The acoustic enhancement composite material according to any one of claims 1 to 4, characterized in that: The fibrous material includes organic fibers.

6. The acoustic enhancement composite material according to claim 5, characterized in that: The organic fibers include hydrophilic natural fibers and / or chemical synthetic fibers.

7. The acoustic enhancement composite material according to claim 5 or 6, characterized in that: The organic fibers include hydrophilic natural fibers and chemical synthetic fibers, wherein the absolute dry weight ratio of the hydrophilic natural fibers to the chemical synthetic fibers is 100-80:0-20, preferably 100-95:0-5.

8. The acoustic enhancement composite material according to claim 7, characterized in that: The chemical synthetic fibers include chemical synthetic fibers that have not been hydrophilically modified and / or hydrophilically modified chemical synthetic fibers obtained by hydrophilically modifying chemical synthetic fibers that have not been hydrophilically modified, preferably hydrophilically modified chemical synthetic fibers; Wherein, the chemical synthetic fiber that has not been hydrophilically modified includes one or a combination of polypropylene fiber, polyamide fiber, polyethylene fiber, polyester fiber, polylactic acid fiber, polyetheretherketone fiber, polyphenylene sulfide fiber and polyacrylonitrile fiber; The hydrophilically modified chemical synthetic fiber includes one or a combination of hydrophilically modified polypropylene fiber, hydrophilically modified polyamide fiber, hydrophilically modified polyethylene fiber, hydrophilically modified polyester fiber, hydrophilically modified polylactic acid fiber, hydrophilically modified polyetheretherketone fiber, hydrophilically modified polyphenylene sulfide fiber and hydrophilically modified polyacrylonitrile fiber.

9. The acoustic enhancement composite material according to any one of claims 6 to 8, characterized in that: The cross-sectional shape of the chemical synthetic fiber includes circular, flat or special-shaped shapes, wherein the special-shaped shapes include cross structure, skin-core structure, triangle structure, clover structure, W-shaped structure, Y-shaped structure or hollow structure.

10. The acoustic enhancement composite material according to any one of claims 6 to 9, characterized in that: The hydrophilic natural fiber includes one or a combination of plant fiber, regenerated cellulose fiber and bacterial fiber, wherein the absolute dry mass ratio of the plant fiber, the regenerated cellulose fiber and the bacterial fiber is 100-60:0-30:0-10, preferably 100-85:0-10:0-5.

11. The acoustic enhancement composite material according to any one of claims 6 to 8 and 10, characterized in that: When the fibrous material is plant fiber and hydrophilically modified chemical synthetic fiber, the absolute dry mass ratio of the two is 98-70:2-30, preferably 95-80:5-20.

12. The acoustic enhancement composite material according to claim 10 or 11, characterized in that: The plant fibers include fine plant fibers and / or coarse plant fibers, wherein the diameter or width of the fine plant fibers is greater than or equal to 8 μm and less than 30 μm, and the diameter or width of the coarse plant fibers is in the range of 30-70 μm; The absolute dry mass ratio of the coarse plant fibers to the fine plant fibers is 100-0:0-100, preferably 100-30:0-70.

13. The acoustic enhancement composite material according to claim 10 or 11, characterized in that: The aspect ratio of the plant fiber is 8-150.

14. The acoustic enhancement composite material according to any one of claims 10 to 13, characterized in that: The plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reed and cotton.

15. The acoustic enhancement composite material according to claim 10, characterized in that: The regenerated cellulose fiber includes one or a combination of viscose fiber, modal fiber, lyocell fiber, acetate fiber, cupro fiber and tencel fiber.

16. The acoustic enhancement composite material according to claim 10, characterized in that: The bacterial fiber includes cellulose fiber synthesized by microorganisms under certain conditions using nutrients required for bacterial growth and reproduction as raw materials, wherein the microorganisms include Acetobacter, Agrobacterium, Rhizobium or Sarcina.

17. The acoustic enhancement composite material according to any one of claims 1 to 4, characterized in that: The fibrous material includes one or a combination of inorganic fibers, plant fibers and chemical fibers of composite components.

18. The acoustic enhancement composite material according to claim 17, characterized in that: The inorganic fiber has a diameter or width ranging from 3 to 45 μm and an aspect ratio of 10 to 500.

19. The acoustic enhancement composite material according to claim 17 or 18, characterized in that: The inorganic fiber includes one or a combination of basalt fiber, glass fiber, quartz fiber, asbestos fiber, volcanic rock fiber, metal fiber, alumina fiber and carbon fiber.

20. The acoustic enhancement composite material according to claim 17, characterized in that: The diameter or width of the plant fiber is in the range of 8-70 μm, and the aspect ratio is in the range of 8-150.

21. The acoustic enhancement composite material according to claim 17 or 20, characterized in that: The moisture absorption ratio of the plant fiber is 16.0-31.5%, preferably 20.0-31.5%.

22. The acoustic enhancement composite material according to claim 21, characterized in that: The plant fiber is a fibrous material made from natural plants as raw materials, wherein the natural plants include one or a combination of coniferous wood, broad-leaved wood, hemp, bamboo, straw, bagasse, reed and cotton.

23. The acoustic enhancement composite material according to claim 17, characterized in that: The diameter or width of the chemical fiber of the composite component is in the range of 10-70 μm, and the aspect ratio is in the range of 10-200.

24. The acoustic enhancement composite material according to claim 17 or 23, characterized in that: The chemical fiber of the composite component includes one or a combination of chemical fibers of composite components having a core-skin structure, a parallel structure, and a sea-island structure.

25. The acoustic enhancement composite material according to claim 24, characterized in that: The chemical fibers of the parallel structure composite components include chemical fibers with a melting point not higher than 140°C and chemical fibers with a melting point not lower than 150°C.

26. The acoustic enhancement composite material according to claim 25, characterized in that: The chemical fibers having a melting point not higher than 140° C. include polyethylene fibers and / or modified polyester fibers, and the chemical fibers having a melting point not lower than 150° C. include ordinary polyester fibers and / or polypropylene fibers.

27. The acoustic enhancement composite material according to claim 24, characterized in that: The material of the matrix of the chemical fiber of the sea-island structure composite component includes chemical fiber with a melting point not higher than 140°C, and the material of the dispersed phase includes chemical fiber with a melting point not lower than 150°C.

28. The acoustic enhancement composite material according to claim 27, characterized in that: The material of the matrix includes polyethylene fiber and / or modified polyester fiber, and the material of the dispersed phase includes ordinary polyester fiber and / or polypropylene fiber.

29. The acoustic enhancement composite material according to claim 24, characterized in that: The chemical fiber of the core-skin structure composite component includes a core layer and a skin layer covering the core layer, and the material of the skin layer includes chemical fiber with a melting point not higher than 140°C, and the material of the core layer includes chemical fiber with a melting point not lower than 150°C.

30. The acoustic enhancement composite material according to claim 29, characterized in that: The core layer comprises ordinary polyester fibers and / or polypropylene fibers, and the skin layer comprises polyethylene fibers and / or modified polyester fibers.

31. The acoustically enhanced composite material according to claim 17, characterized in that: The absolute dry weight ratio of the plant fiber to the chemical fiber of the composite component is 98-60:2-40.

32. The acoustic enhancement composite material according to claim 1, characterized in that: The porous powder material includes one or a combination of zeolite molecular sieve, activated silicon dioxide, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, aluminum oxide, hydrogel, and aerogel.

33. The acoustic enhancement composite material according to claim 32, characterized in that: The particle size of the zeolite molecular sieve is 0.5-10 μm, including micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

34. The acoustic enhancement composite material according to claim 32 or 33, characterized in that: The zeolite molecular sieve includes one or a combination of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve and MTT structure molecular sieve.

35. The acoustic enhancement composite material according to claim 1, characterized in that: The precipitation aid comprises one or a combination of polyacrylamide, starch, polyethyleneimine, polyimide and guar gum.

36. The acoustic enhancement composite material according to any one of claims 1 to 4, characterized in that: The acoustically enhanced composite material has a grammage range of 50-1200 g / m 2 .

37. The acoustic enhancement composite material according to any one of claims 1 to 4, characterized in that: The shape of the acoustic enhancement composite material includes a sheet shape, a block shape or an irregular shape.

38. The method for preparing the acoustically enhanced composite material according to any one of claims 1 to 37, characterized in that: The production method comprises: Step 1: Dispersing the fibrous material, the porous powder material and the precipitation aid in water respectively to obtain a fibrous material dispersion, a porous powder material dispersion and a precipitation aid dispersion; Step 2: adding the porous powder material dispersion into the fibrous material dispersion and mixing them evenly, and then adding the precipitation aid dispersion and mixing them evenly, so that the fibrous materials are intertwined with each other and the porous powder material is precipitated on the surface of the fibrous material at the same time; Step 3: Filter the mixed solution obtained in step 2 to obtain a precursor material; Step 4: Drying the precursor material to obtain an acoustically enhanced composite material.

39. The method according to claim 38, characterized in that: When the fibrous material comprises chemical fibers of a composite component, the manufacturing method further comprises: Step 5: Under the condition that the temperature is not lower than the melting point of the skin layer contained in the chemical fiber of the composite component, the acoustic enhancement material is subjected to high temperature treatment so that the skin layer of the chemical fiber of the composite component melts but the core layer does not melt.

40. A speaker, 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 speaker back cavity, characterized in that: The loudspeaker rear cavity is equipped with the acoustically enhanced composite material described in any one of claims 1-37.

41. An electronic device, characterized in that: The acoustically enhanced composite material according to any one of claims 1 to 37 is installed in the speaker rear cavity of the electronic device.

42. The electronic device according to claim 41, characterized in that The electronic device includes a smart phone, a TWS headset, a head-mounted headset, smart glasses, a smart watch, a VR device, an AR device, a tablet computer or a thin and light laptop computer.

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