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

Abstract

The application provides an acoustic enhancement composite material, a manufacturing method thereof, and a loudspeaker and electronic equipment, wherein the acoustic enhancement composite material is formed by interweaving fibrous materials with each other, has a three-dimensional network structure inside, and has porous powder materials attached to the surfaces of the fibrous materials through a precipitation aid. The acoustic enhancement composite material has high acoustic performance, and the acoustic performance of the porous powder material with the acoustic enhancement function per unit mass is better than that of commonly used acoustic enhancement particles on the market. The acoustic enhancement composite material also has stable acoustic performance, and after high-temperature and high-humidity storage according to the technical content recorded in 7.8.4 of the group standard 'Porous sound-absorbing particles for micro loudspeakers' (standard number: T / CECA 78-2022), the acoustic performance of the acoustic enhancement composite material has no loss.

Description

Technical Field

[0001] This invention relates to an acoustically reinforced composite material, its manufacturing method, and loudspeakers and electronic devices, belonging to the field of materials technology, particularly the field of electronic acoustic materials technology. Background Technology

[0002] As electronic products such as mobile phones, tablets, and laptops become increasingly thinner and lighter, the resonant cavities of their speaker system components are also shrinking. It is well known that smaller speaker resonant cavities lead to higher resonant frequencies and lower low-frequency sound pressure level sensitivity, while consumers' demands for audio quality in these products are constantly increasing. To resolve this contradiction, acoustic enhancement materials have emerged.

[0003] Preparing porous powder materials capable of efficiently adsorbing and releasing air molecules into sound-absorbing particles with an average particle size of 200-800 μm using molding technology, and then filling these particles into the cavity of a loudspeaker, is a conventional method for improving the audio quality of small-cavity loudspeakers. However, this method also has certain shortcomings. For example, firstly, current technology typically fills the loudspeaker cavity with sound-absorbing particles through a canning process, which is quite difficult. Especially for some miniature loudspeakers with extremely small resonant cavities, with heights ranging from hundreds of micrometers, quantitatively filling such a confined space with sound-absorbing particles is virtually impossible. Yet, these narrow resonant cavities often have the greatest impact on low frequencies and are the structures most in need of sound-absorbing material. Secondly, during loudspeaker operation, traditional sound-absorbing particles vibrate at high frequencies within the cavity and collide with the inner wall, leading to particle breakage and fragmentation, damaging the loudspeaker unit. Furthermore, in current filling processes, sound-absorbing particles can only fill about 80% of the rear cavity volume of the loudspeaker module, failing to fully utilize the rear cavity space.

[0004] Therefore, providing a novel acoustically reinforced composite material and its manufacturing method, as well as loudspeakers and electronic devices, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] In order to overcome the above-mentioned shortcomings and deficiencies, one object of the present invention is to provide an acoustically reinforced composite material.

[0006] Another object of the present invention is to provide a method for manufacturing the acoustically reinforced composite material described above.

[0007] Another object of the present invention is to provide a loudspeaker in which the acoustically enhanced composite material described above is assembled in the rear cavity.

[0008] Another object of the present invention is to provide an electronic device in which the acoustically enhanced composite material described above is assembled in the rear cavity of a speaker.

[0009] To achieve the above objectives, on the one hand, the present invention provides an acoustically reinforced composite material, wherein the acoustically reinforced composite material is composed of interwoven fibrous materials, having a three-dimensional network structure inside, and porous powder material is attached to the surface of the fibrous materials by a precipitation aid.

[0010] In the acoustically reinforced composite material provided by the present invention, porous powder material is attached to the three-dimensional network structure and the surface of the acoustically reinforced composite material.

[0011] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the fibrous material accounts for 19.50-85.95% of the total weight of the acoustically reinforced composite material, the porous powder material accounts for 14.0-80.0% of the dry mass, and the precipitation aid accounts for 0.05-0.5% of the dry mass.

[0012] In this invention, the smaller the diameter or width of the fibrous material and the smaller its aspect ratio, the larger its specific surface area under the same mass, meaning it has more surface area to interact with the porous powder material with acoustic enhancement function. Conversely, the larger the diameter or width of the fibrous material and the larger its aspect ratio, the richer the interweaving between the fibrous materials, the more complex the three-dimensional network structure formed, and the better the physical strength of the resulting acoustically enhanced composite material. However, if the diameter or width of the fibrous material is too large, the surface of the acoustically enhanced composite material made from it will be rougher and uneven. If the aspect ratio of the fibrous material is too large, it will be difficult to disperse the fibrous material in water, and the fibrous materials will entangle with each other, making it difficult to disperse into single fibers. Accordingly, as a specific embodiment of the acoustically enhanced composite material described above in this invention, the diameter or width of the fibrous material ranges from 8 to 70 μm, and the aspect ratio ranges from 8 to 500, preferably 8 to 150. In this 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 its width.

[0013] In one specific embodiment of the acoustically reinforced composite material described above in this invention, the fibrous material includes organic fibers.

[0014] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the organic fiber includes hydrophilic natural fibers and chemically synthesized fibers, etc., wherein the oven-dry mass ratio of the hydrophilic natural fibers and chemically synthesized fibers is 100-80:0-20, preferably 100-95:0-5, and preferably, the organic fiber is a hydrophilic natural fiber.

[0015] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the chemically synthesized fiber includes unmodified chemically synthesized fiber and / or hydrophilically modified chemically synthesized fiber obtained by hydrophilic modification of unmodified chemically synthesized fiber, preferably hydrophilically modified chemically synthesized fiber.

[0016] The unmodified chemical synthetic fibers include one or a combination of several of the following: polypropylene fiber, polyamide fiber, polyethylene fiber, polyester fiber, polylactic acid fiber, polyetheretherketone fiber, polyphenylene sulfide fiber, and polyacrylonitrile fiber.

[0017] This invention does not specify the hydrophilic modifying agent used for hydrophilic modification of chemically synthesized fibers; it can be selected reasonably according to actual operational needs. For example, in some embodiments of this invention, the hydrophilic modifying agent can be maleic anhydride, and correspondingly, the hydrophilic modified chemically synthesized fibers can be maleic anhydride-modified polypropylene fibers or maleic anhydride-modified polyester fibers, etc.

[0018] The chemically synthesized fibers used in this invention are characterized by the absence of significant inter-fiber forces, such as hydrogen bonding and electrostatic attraction, and their low density. The mechanical interweaving force between these fibrous materials is the main interaction force, which can construct a three-dimensional spatial structure with high porosity, i.e., a three-dimensional network structure, which facilitates air circulation.

[0019] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the cross-sectional shape of the chemically synthesized fiber includes circular, flat, or irregular shapes, etc., wherein the irregular shapes include cross structure, core-sheath structure, triangular structure, clover structure, king-shaped structure, Y-shaped structure, or hollow structure, etc.

[0020] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the hydrophilic natural fiber includes one or a combination of several of plant fibers, regenerated cellulose fibers and bacterial fibers, wherein the oven-dry mass ratio of plant fibers, regenerated cellulose fibers and bacterial fibers is 100-60:0-30:0-10, preferably 100-85:0-10:0-5.

[0021] The hydrophilic natural fibers used in this invention include plant fibers, regenerated cellulose fibers, and bacterial fibers. These fibrous materials contain numerous hydrophilic groups in their chemical structures, such as hydroxyl and carboxyl groups. When the acoustic reinforcement composite material made of hydrophilic natural fibers is assembled into the rear cavity of a loudspeaker, water molecules in the air are preferentially absorbed and fixed by the hydrophilic natural fibers during actual use. This reduces the performance degradation of porous powder materials caused by water molecules, significantly improving the service life of the acoustic reinforcement composite material within the rear cavity.

[0022] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the plant fibers can be divided into two categories according to their diameter or width: fine plant fibers and / or coarse plant fibers. The diameter or width of the fine plant fibers is greater than or equal to 8 μm and less than 30 μm, while the diameter or width of the coarse plant fibers is 30-70 μm.

[0023] The ratio of the oven-dry weight of coarse plant fibers to fine plant fibers is 100-0:0-100, preferably 100-30:0-70.

[0024] In one specific embodiment of the acoustically reinforced composite material described above in this invention, the aspect ratio of the plant fiber is 8-150.

[0025] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the plant fiber is a fibrous material made from natural plants, wherein the natural plants include one or a combination of several of the following: coniferous wood, broadleaf wood, hemp, bamboo, rice straw, sugarcane bagasse, reeds, and cotton.

[0026] The method for preparing plant fibers from natural plants is a conventional method, and its preparation method can be reasonably adjusted according to the characteristics of 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 of the hemicellulose from the natural plant, and then performing bleaching treatment or without bleaching treatment to obtain a fibrous material mainly composed of cellulose, i.e., the plant fiber.

[0027] In this invention, the regenerated cellulose fiber is a fibrous material obtained by further processing high-purity cellulose from natural plant sources. As a specific embodiment of the acoustically reinforced composite material described above, the regenerated cellulose fiber includes one or a combination of several of viscose fiber, modal fiber, lyocell fiber, acetate fiber, cuprammonium fiber, and Tencel fiber.

[0028] In this invention, the bacterial fiber is a fibrous material derived from bacterial microorganisms, which is a fiber prepared using biological methods. As a specific embodiment of the acoustically reinforced composite material described above, 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 acetic acid bacteria, agrobacterium, rhizobium, or sarcodactylus, etc.

[0029] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the fibrous material may be a single organic fiber, 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.

[0030] The porous powder material used in this invention has acoustic enhancement function, and porous powder materials commonly used in the art for preparing acoustic enhancement materials can be selected. As a specific embodiment of the acoustic enhancement composite material described above in this invention, the porous powder material includes one or a combination of several of the following: zeolite molecular sieves, activated silica, activated carbon, porous calcium carbonate, porous calcium silicate, alumina, hydrogels, and aerogels.

[0031] As a specific embodiment of the acoustically enhanced composite material described above in this invention, the zeolite molecular sieve has a particle size of 0.5-10 μm and includes micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

[0032] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the zeolite molecular sieve includes one or a combination of several of the following: 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.

[0033] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the precipitation aid includes one or a combination of several of the following: polyacrylamide, starch, polyethyleneimine, polyimide, and guar gum.

[0034] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the basis weight range of the acoustically reinforced composite material is 50-1200 g / m³. 2 .

[0035] As a specific embodiment of the acoustically reinforced composite material described above in this invention, the shape of the acoustically reinforced composite material includes sheet-like, block-like, or irregular shapes. When applying this acoustically reinforced composite material, those skilled in the art can reasonably select an acoustically reinforced composite material of a suitable shape as needed. Alternatively, those skilled in the art can also obtain an acoustically reinforced composite material of the target shape by combining the manufacturing method provided by this invention with existing conventional methods.

[0036] On the other hand, the present invention also provides a method for manufacturing the above-described acoustically reinforced composite material, wherein the manufacturing method includes:

[0037] Step 1: Disperse the fibrous material, porous powder material, and precipitation aid separately in water to obtain a fibrous material dispersion, a porous powder material dispersion, and a precipitation aid dispersion.

[0038] Step 2: Add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0039] Step 3: Filter the mixture obtained in Step 2 to obtain the precursor material;

[0040] Step 4: The precursor material is then dried to obtain the acoustically reinforced composite material.

[0041] As a specific embodiment of the above-described manufacturing method of the present invention, in step one, the total weight of the fibrous material dispersion is 100%, wherein the oven-dry mass concentration of the fibrous material is 0.5-4%.

[0042] As a specific embodiment of the manufacturing method described above in this invention, in step one, the total weight of the porous powder material dispersion is 100%, wherein the oven-dry mass concentration of the porous powder material is 1-50%.

[0043] As a specific embodiment of the preparation method described above in this invention, in step one, the total weight of the precipitating agent dispersion is 100%, wherein the oven-dry mass concentration of the precipitating agent is 0.01-4.00%.

[0044] As a specific embodiment of the manufacturing method described above in this invention, in step one, the water includes one or more of deionized water, distilled water, and reverse osmosis water, in a mixture.

[0045] In one specific embodiment of the manufacturing method described above, step two is performed under stirring conditions to achieve faster and better uniform mixing. In step two, the interweaving of the fibrous materials and the precipitation of porous powder materials on the surface of the fibrous materials occur simultaneously.

[0046] In one specific embodiment of the manufacturing method described above, in step three, the mixture obtained in step two is filtered to initially remove water from the mixture, and the water content of the resulting material can be 10-80 wt%. The filtration in step three is a standard operation and can be adjusted according to the actual on-site conditions. For example, in some embodiments of the present invention, the filtration is vacuum filtration.

[0047] The present invention can control the shape of the obtained acoustically reinforced composite material through the filtration operation in step three. If filtration is performed multiple times in step three, the thickness of the material stack will increase, resulting in a blocky acoustically reinforced composite material. That is, the present invention can control the thickness of the acoustically reinforced composite material through filtration. Alternatively, different shaped molds can be selected for filtration as needed to obtain irregularly shaped acoustically reinforced composite materials. Of course, the blocky or irregularly shaped acoustically reinforced composite materials obtained after drying can also be cut to obtain irregularly shaped acoustically reinforced composite materials.

[0048] In one specific embodiment of the manufacturing method described above, step four, the drying process, is a conventional operation and can be adjusted according to the actual on-site conditions, as long as the moisture in the precursor material can be removed. For example, in some embodiments of the present invention, the drying process involves using equipment such as a vacuum freeze dryer or a forced-air drying oven to dry the precursor material.

[0049] In aqueous systems, there is no interaction between porous powder materials and fibrous materials that provide acoustic enhancement. Therefore, a precipitation aid is used in the fabrication of the acoustically enhanced composite material. This precipitation aid has adhesive properties, which can precipitate the particles of the porous powder material onto the surface of the fibrous material.

[0050] In another aspect, the present invention also provides a loudspeaker, including one or more acoustic sensors and one or more housings, wherein the one or more acoustic sensors and the one or more housings are combined to form a rear cavity of the loudspeaker, wherein the rear cavity of the loudspeaker is fitted with the acoustically reinforced composite material described above.

[0051] In another aspect, the present invention also provides an electronic device in which the acoustically enhanced composite material described above is assembled in the rear cavity of the speaker of the electronic device.

[0052] As a specific embodiment of the electronic device described above in this invention, the electronic device includes smartphones, TWS earphones, headphones, smart glasses, smartwatches, VR devices, AR devices, tablet computers, or thin and light laptops, etc.

[0053] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0054] 1. High-efficiency mass production: This invention enables the high-efficiency mass production of acoustically reinforced composite materials without the need for special equipment, raw materials, or chemicals.

[0055] 2. Arbitrary cutting: The acoustic reinforcement 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.

[0056] 3. High acoustic performance: The acoustically reinforced composite material provided by this invention has high acoustic performance. For a unit mass of porous powder material with acoustic reinforcement function, its acoustic performance is better than that of commonly used acoustically reinforced particles on the market.

[0057] 4. The acoustically reinforced composite material provided by this invention has stable acoustic properties. After being stored at high temperature and high humidity according to the technical content described in section 7.8.4 of the group standard "Porous Sound Absorbing Particles for Miniature Loudspeakers" (standard number: T / CECA 78-2022), its acoustic properties are not lost. Attached Figure Description

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0059] Figure 1 The surface morphology of the sheet-like acoustically reinforced composite material obtained in Example 1 of the present invention is shown.

[0060] Figure 2 The surface morphology of the sheet-like acoustically reinforced composite material obtained in Example 3 of the present invention is shown.

[0061] Figure 3 The surface morphology of the sheet-like acoustically reinforced composite material obtained in Example 4 of the present invention is shown.

[0062] Figure 4 The surface morphology of the sheet-like acoustically reinforced composite material obtained in Example 6 of the present invention is shown.

[0063] Figure 5 The surface morphology of the sheet-like acoustically reinforced composite material obtained in Example 7 of the present invention is shown.

[0064] Figure 6 The surface morphology of the sheet-like acoustically reinforced composite material obtained in Example 8 of the present invention is shown.

[0065] Figure 7 This is a SEM image of the sheet-like acoustically reinforced composite material provided in Embodiment 2 of the present invention. Detailed Implementation

[0066] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0067] The "range" disclosed in this 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 and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0068] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of 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" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0069] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0070] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0071] In this invention, unless otherwise specified, the term "two kinds" as used in this specification means "at least two kinds".

[0072] In this invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, if the method includes steps (a) and (b), it means that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, if the method may also include step (c), it means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0073] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0074] In the embodiments, the oven-dry mass percentage of porous powder material in the sheet-like acoustic reinforced composite material can be measured using the following method:

[0075] After drying the sheet-like acoustic reinforcement composite material to constant weight in an oven at 110°C, its mass is accurately measured and recorded as A.

[0076] The mass of the dried crucible is recorded as B. The sheet-like acoustic reinforcement composite material with a mass of A is placed into the dried crucible. The crucible is then placed in a high-temperature muffle furnace and the heating program is set to 0.5℃ / min. The temperature is raised from room temperature to 525℃ and held for 120min. Then it is cooled to room temperature.

[0077] Weigh the crucible and the total weight of the porous powder material inside it, and record it as C;

[0078] After a sheet-like acoustic reinforcement composite material with mass A is calcined at high temperature, the mass of the porous powder material contained therein is denoted as D, then D = CB; the percentage of the oven-dry mass of the porous powder material in the sheet-like acoustic reinforcement composite material with mass A is denoted as E, then E = (D / A) × 100%.

[0079] Example 1

[0080] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0081] The fibrous material is 100% coarse plant fiber, which is hydroxyl-containing coniferous wood fiber with an average width of 45 μm and an aspect ratio of 70.

[0082] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0083] The porous powder material is ZSM-5 molecular sieve with 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.

[0084] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 19.50%, the oven-dry mass percentage of the porous powder material is 80.0%, and the oven-dry mass percentage of the precipitation aid is 0.5%.

[0085] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0086] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0087] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0088] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0089] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0090] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0091] Example 2

[0092] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0093] The fibrous material is composed of coarse plant fibers and fine plant fibers. 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 29.60% of the oven-dry weight. 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 10% of the oven-dry weight.

[0094] In fibrous materials, the ratio of the oven-dry weight of coarse plant fibers to fine plant fibers is 74.7:25.3;

[0095] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0096] The porous powder material is ZSM-5 molecular sieve with 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.

[0097] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 39.60%, the oven-dry mass percentage of the porous powder material is 60.0%, and the oven-dry mass percentage of the precipitation aid is 0.4%.

[0098] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0099] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0100] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0101] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0102] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0103] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0104] Example 3

[0105] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0106] The fibrous material is composed of coarse plant fibers, fine plant fibers, and regenerated cellulose fibers. 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 30% of the oven-dry weight. The fine plant fibers are hydroxyl-containing hardwood fibers with an average width of 17 μm and an aspect ratio of 65, accounting for 30% of the oven-dry weight. The regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, accounting for 4.25% of the oven-dry weight.

[0107] In fibrous materials, the oven-dry mass ratio of plant fiber to regenerated cellulose fiber is 93.4:6.6;

[0108] The precipitation aid is guar gum with an average relative molecular weight of 1.6 million.

[0109] The porous powder material is ZSM-5 molecular sieve with 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.

[0110] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 64.25%, the oven-dry mass percentage of the porous powder material is 35.5%, and the oven-dry mass percentage of the precipitation aid is 0.25%.

[0111] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0112] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0113] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0114] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0115] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0116] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0117] Example 4

[0118] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0119] The fibrous material comprises coarse plant fibers, fine plant fibers, regenerated cellulose fibers, and chemically synthesized fibers. 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 48.5% of the oven-dry weight. The fine plant fibers are hydroxyl-containing hardwood fibers with an average width of 17 μm and an aspect ratio of 65, accounting for 30% of the oven-dry weight. The regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, accounting for 3.0% of the oven-dry weight. The chemically synthesized fibers are maleic anhydride-modified polyester fibers with an average diameter of 15 μm and an aspect ratio of 100, accounting for 4.45% of the oven-dry weight.

[0120] In sheet-like acoustic reinforced composite materials, plant fibers include coarse plant fibers and fine coarse plant fibers, totaling 78.5%;

[0121] Among all fibrous materials, the ratio of oven-dry mass of plant fiber, regenerated cellulose fiber, and chemically synthesized fiber is 91.33:3.49:5.18.

[0122] Among all fibrous materials, hydrophilic natural fibers include coarse plant fibers, fine coarse plant fibers, and viscose fibers. The ratio of the oven-dry weight of hydrophilic natural fibers to that of chemically synthesized fibers is 94.82:5.18.

[0123] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0124] The porous powder material is ZSM-5 molecular sieve with 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.

[0125] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 85.95%, the oven-dry mass percentage of the porous powder material is 14.0%, and the oven-dry mass percentage of the precipitation aid is 0.05%.

[0126] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0127] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0128] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0129] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0130] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0131] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0132] Example 5

[0133] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0134] 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, accounting for 81.32% of the oven-dry weight.

[0135] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0136] The porous powder material is ZSM-5 molecular sieve with 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.

[0137] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 81.32%, the oven-dry mass percentage of the porous powder material is 18.62%, and the oven-dry mass percentage of the precipitation aid is 0.06%.

[0138] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0139] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0140] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0141] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0142] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0143] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0144] Example 6

[0145] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0146] The fibrous material is a hydrophilic 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 oven-dry weight percentage of 19.50%.

[0147] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0148] The porous powder material is ZSM-5 molecular sieve with 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.

[0149] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 19.50%, the oven-dry mass percentage of the porous powder material is 80.0%, and the oven-dry mass percentage of the precipitation aid is 0.5%.

[0150] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0151] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0152] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0153] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0154] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0155] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0156] Example 7

[0157] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0158] The fibrous material is composed of hydrophilic modified chemical synthetic fibers, wherein the hydrophilic modified chemical synthetic fibers are maleic anhydride modified polypropylene fibers with an average width of 45 μm and an aspect ratio of 70, and an oven-dry weight percentage of 39.60%.

[0159] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0160] The porous powder material is ZSM-5 molecular sieve with 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.

[0161] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 39.60%, the oven-dry mass percentage of the porous powder material is 60.0%, and the oven-dry mass percentage of the precipitation aid is 0.4%.

[0162] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0163] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0164] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0165] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0166] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0167] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0168] Example 8

[0169] This embodiment provides a sheet-like acoustically reinforced composite material with a basis weight of 500 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforced composite material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by precipitation aid.

[0170] The fibrous material is composed of hydrophilic modified synthetic fibers and virgin synthetic fibers, i.e., unmodified synthetic fibers. The hydrophilic modified synthetic fibers are maleic anhydride-modified polyester fibers with an average width of 15 μm and an aspect ratio of 100, accounting for 44.25% of the total dry weight. The virgin synthetic fibers are ordinary polyester fibers with an average width of 15 μm and an aspect ratio of 100, accounting for 20.00% of the total dry weight.

[0171] The oven-dry mass ratio of the hydrophilic modified chemical synthetic fiber to the original chemical synthetic fiber is 68.9:31.1;

[0172] The precipitation aid is guar gum with an average relative molecular weight of 1.6 million.

[0173] The porous powder material is ZSM-5 molecular sieve with 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.

[0174] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 64.25%, the oven-dry mass percentage of the porous powder material is 35.5%, and the oven-dry mass percentage of the precipitation aid is 0.25%.

[0175] In this embodiment, the sheet-like acoustically reinforced composite material is prepared by a method including the following specific steps:

[0176] Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water according to the above formula to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion.

[0177] Among them, based on the total weight of the fibrous material dispersion liquid as 100%, the oven-dry mass concentration of the fibrous material is 2.0%; based on the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material is 20%; and based on the total weight of the precipitating agent dispersion liquid as 100%, the oven-dry mass concentration of the precipitating agent is 0.02%.

[0178] Step 2: Under stirring conditions, add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials.

[0179] Step 3: Filter the mixture obtained in Step 2 to obtain sheet material with a water content of 70 wt%.

[0180] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After forced-air drying, a sheet acoustic reinforced composite material is obtained. The oven-dry mass ratio of porous powder material in the sheet acoustic reinforced composite material is measured using the method shown above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0181] Comparative Example 1

[0182] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 1 only in that:

[0183] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 14.0%, the oven-dry mass percentage of the porous powder material is 85.0%, and the oven-dry mass percentage of the precipitation aid is 1.0%.

[0184] Comparative Example 2

[0185] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 4 only in that:

[0186] Based on the total weight of the sheet-like acoustic reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 90.95%, the oven-dry mass percentage of the porous powder material is 9.0%, and the oven-dry mass percentage of the precipitation aid is 0.05%.

[0187] The fibrous material comprises coarse plant fibers, fine plant fibers, regenerated cellulose fibers, and chemically synthesized fibers. 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 48.5% of the oven-dry weight. The fine plant fibers are hydroxyl-containing hardwood fibers with an average width of 17 μm and an aspect ratio of 65, accounting for 35% of the oven-dry weight. The regenerated cellulose fibers are viscose fibers with an average diameter of 28 μm and an aspect ratio of 100, accounting for 3.0% of the oven-dry weight. The chemically synthesized fibers are maleic anhydride-modified polyester fibers with an average diameter of 15 μm and an aspect ratio of 100, accounting for 4.45% of the oven-dry weight.

[0188] Comparative Example 3

[0189] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 1 only in that:

[0190] The hydrophilic fiber is 100% coarse plant fiber, which is hydroxyl-containing coniferous wood fiber with an average width of 45 μm and an aspect ratio of 7.5.

[0191] Comparative Example 4

[0192] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 5 only in that:

[0193] The hydrophilic fiber 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 510.

[0194] Comparative Example 5

[0195] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 2 only in that:

[0196] The hydrophilic fiber is composed of coarse plant fibers and fine plant fibers. 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 25.3% of the oven-dry weight. 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 74.7% of the oven-dry weight.

[0197] Comparative Example 6

[0198] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 6 only in that:

[0199] The fibrous material is composed of virgin chemically synthesized fibers, wherein the virgin chemically synthesized fibers are ordinary polyester fibers without maleic anhydride modification, with an average width of 15 μm and an aspect ratio of 100, and an oven-dry weight percentage of 19.50%.

[0200] Comparative Example 7

[0201] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 7 only in that:

[0202] The fibrous material is composed of virgin chemically synthesized fibers, wherein the virgin chemically synthesized 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, accounting for 39.60% of the total dry weight.

[0203] Comparative Example 8

[0204] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 6 only in that:

[0205] The hydrophilic modified chemical synthetic fiber is a maleic anhydride modified polypropylene fiber with an average width of 15μm and an aspect ratio of 7.5.

[0206] Comparative Example 9

[0207] This comparative example provides a sheet-like acoustically reinforced composite material, which differs from Example 6 only in that:

[0208] The hydrophilic modified chemical synthetic fiber is a maleic anhydride modified polypropylene fiber with an average width of 15μm and an aspect ratio of 510.

[0209] Test Example 1

[0210] In this test example, the sheet-like acoustic reinforcement composite materials provided in Examples 1-8 and Comparative Examples 1-9 were first cut into 10*10mm sizes and weighed. Then, the resonant frequency shift value Δf0 of the sheet-like acoustic reinforcement composite materials was tested according to part 7.4 of the group standard "Porous Sound Absorbing Particles for Miniature Loudspeakers" (standard number: T / CECA78-2022). The specific results are shown in Table 1 below.

[0211] Table 1. Acoustic performance data of sheet-like acoustic reinforced composite materials in Examples 1-8 and Comparative Examples 1-9.

[0212]

[0213] After calculation, the sheet-like acoustic reinforcement composite materials obtained in Examples 1-8 and Comparative Examples 1-9 were cut into 10*10mm sizes. The oven-dry mass of molecular sieve in each sheet-like acoustic reinforcement composite material was 40.0mg, 30.0mg, 17.75mg, 7.0mg, 9.31mg, 40.0mg, 30.0mg, 17.75mg, 42.5mg, 4.5mg, 40.0mg, 9.31mg, 30.0mg, 40.0mg, 30.0mg, 40.0mg, and 30.0mg.

[0214] The acoustic efficiency per unit mass of sheet-like acoustically reinforced composite material was then calculated using the formula shown below, and the resulting acoustic efficiency data are shown in Table 2.

[0215] Acoustic efficiency = Δf0 / (ocean-dry mass of molecular sieve), unit: Hz / mg.

[0216] Table 2. Acoustic efficiency data of sheet-like acoustic reinforced composite materials in Examples 1-8 and Comparative Examples 1-9.

[0217] Acoustic efficiency Hz / mg Example 1 1.225 Example 2 1.333 Example 3 1.521 Example 4 2.286 Example 5 2.148 Example 6 1.250 Example 7 1.267 Example 8 1.465 Comparative Example 1 0.894 Comparative Example 2 1.778 Comparative Example 3 1.000 Comparative Example 4 1.396 Comparative Example 5 1.267 Comparative Example 6 1.250 Comparative Example 7 1.267 Comparative Example 8 1.000 Comparative Example 9 0.975

[0218] As can be seen from the experimental data in Tables 1 and 2 above, the sheet-like acoustic reinforced composite materials provided in Examples 1-8 of the present invention all have high-efficiency acoustic properties.

[0219] The experimental data in Tables 1 and 2 above also show that, compared to Example 1 of the present invention which only uses coarse plant fibers as fibrous materials, Example 2 which uses a combination of coarse and fine plant fibers, Example 3 which uses a combination of coarse plant fibers, fine plant fibers, and regenerated cellulose fibers, and Example 4 which uses a combination of coarse plant fibers, fine plant fibers, regenerated cellulose fibers, and chemically synthesized fibers as fibrous materials, the acoustic efficiency of the sheet-like acoustic reinforced composite materials provided in Examples 2 to 4 increases sequentially and is superior to that provided in Example 1.

[0220] The experimental data in Tables 1 and 2 above also show that in the sheet-like acoustic reinforced composite material provided in Comparative Example 1, the dry mass ratio of molecular sieve is 85.0%, which is higher than 80.0% in Example 1. However, its acoustic performance and acoustic efficiency are lower than those of Example 1. The reason is that acoustic materials must have a rich porous structure to fully realize their acoustic performance. In the sheet-like acoustic reinforced composite material, the fibrous materials intertwine to form a three-dimensional network structure, and the richness of this structure determines the material's acoustic performance. Since the dry mass ratio of molecular sieve in Comparative Example 1 is 85%, in order to ensure that the molecular sieve can be completely precipitated in the fibrous material network structure, the dry mass ratio of the precipitation aid is 1%. Therefore, the dry mass ratio of the fibrous material is 14.0%. Thus, the three-dimensional network structure of the sheet-like acoustic reinforced composite material in Comparative Example 1 is far less porous than that in Example 1, and therefore the acoustic performance of the molecular sieve cannot be fully realized.

[0221] Similarly, in the sheet-like acoustic reinforced composite material provided in Comparative Example 2, the dry mass percentage of the molecular sieve is 9%. Due to the low percentage of the dry mass of the molecular sieve, the acoustic performance of this sheet-like acoustic reinforced composite material is very limited and meaningless in practical applications. Furthermore, since the dry mass percentage of the molecular sieve is low, and the amount of precipitation aid is not reduced, it will also have a negative impact on the acoustic performance of the molecular sieve. In summary, the acoustic performance and acoustic efficiency of the sheet-like acoustic reinforced composite material provided in Comparative Example 2 are significantly worse than those in Example 4.

[0222] The experimental data in Tables 1 and 2 above also show that, compared with the sheet-like acoustic reinforcement composite material provided in Example 1 of the present invention, the aspect ratio of the coarse plant fibers in the sheet-like acoustic reinforcement composite material provided in Comparative Example 3 is only 7.5, that is, the coarse plant fibers are too short. At this time, the three-dimensional network structure built by them is not ideal and the porosity is insufficient. As a result, the acoustic performance and acoustic efficiency of the sheet-like acoustic reinforcement composite material provided in Comparative Example 3 are also significantly worse than those in Example 1, and the acoustic performance is significantly reduced.

[0223] The experimental data in Tables 1 and 2 above also show that, compared with the sheet-like acoustic reinforced composite material provided in Example 5 of the present invention, the aspect ratio of the fine plant fibers in the sheet-like acoustic reinforced composite material provided in Comparative Example 4 is as high as 510. That is, the fine plant fibers are too long, which makes it difficult for the fine plant fibers to be intertwined and dispersed. As a result, the fibers in the powder are not evenly dispersed, which affects the performance of the powder.

[0224] The experimental data in Tables 1 and 2 above also show that, compared with the sheet-like acoustic reinforcement composite material provided in Example 2 of the present invention, the dry mass ratio of coarse plant fibers to fine plant fibers in the sheet-like acoustic reinforcement composite material provided in Comparative Example 5 is not within the range of 100-30:0-70. Since the fine plant fibers have a smaller width, their specific surface area is larger than that of the coarse fibers. The porous powder particles deposited on their surface will be much higher than those of the coarse fibers, resulting in uneven distribution of porous powder particles in the sheet-like acoustic reinforcement composite material, thus its acoustic performance is slightly worse than that of Example 2.

[0225] The experimental data in Tables 1 and 2 above also show that the acoustic properties of the sheet-like acoustic reinforced composite materials obtained in Example 6 and Comparative Example 6, and Example 7 and Comparative Example 7 are the same. This indicates that the use of hydrophilic modified chemical synthetic fibers does not affect the acoustic properties of the sheet-like acoustic reinforced composite materials.

[0226] The experimental data in Tables 1 and 2 above also show that the acoustic performance of the sheet-like acoustic reinforced composite material provided in Comparative Example 8 is inferior to that of the sheet-like acoustic reinforced 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 within the range of 8-500. That is, the hydrophilic modified chemical synthetic fiber is too short. At this time, the three-dimensional network structure it builds is not ideal and the porosity is insufficient. As a result, the acoustic performance and acoustic efficiency of the sheet-like acoustic reinforced composite material provided in Comparative Example 8 are significantly worse than those of Example 6, and the acoustic performance is significantly reduced.

[0227] The experimental data in Tables 1 and 2 above also show that the acoustic performance of the sheet-like acoustic reinforced composite material provided in Comparative Example 9 is inferior to that of the sheet-like acoustic reinforced composite material provided in Example 6. This is because the aspect ratio of the hydrophilic modified chemical synthetic fiber is as high as 510, which is not within the range of 8-500. That is, the hydrophilic modified chemical synthetic fiber is too long, which makes it difficult for the hydrophilic modified chemical synthetic fiber to be dispersed due to interweaving. As a result, the fiber in the powder is not evenly dispersed, which affects the performance of the powder. Consequently, the acoustic performance and acoustic efficiency of the sheet-like acoustic reinforced composite material provided in Comparative Example 9 are significantly worse than those of Example 6, and the acoustic performance is significantly reduced.

[0228] Test Example 2

[0229] In this test example, the sheet-like acoustic reinforcement composite materials provided in Examples 1-8 and Comparative Examples 1-9 were first cut into 10*10mm sizes. Then, according to the technical content described in section 7.8.4 of the group standard "Porous Sound-absorbing Particles for Miniature Loudspeakers" (Standard No.: T / CECA 78-2022), the high-temperature and high-humidity storage Δf'HTHR of the sheet-like acoustic reinforcement composite materials was tested. The specific results are shown in Table 3 below. Table 3: High-Temperature and High-Humidity Storage Δf'HTHR Test Data of the Sheet-like Acoustic Reinforced Composite Materials Provided in Examples 1-8 and Comparative Examples 1-9

[0230] △f'HTHR Hz Example 1 1 Example 2 0 Example 3 -1 Example 4 1 Example 5 1 Example 6 1 Example 7 0 Example 8 -1 Comparative Example 1 0 Comparative Example 2 1 Comparative Example 3 -1 Comparative Example 4 -1 Comparative Example 5 1 Comparative Example 6 -8 Comparative Example 7 -6 Comparative Example 8 0 Comparative Example 9 -1

[0231] As shown in Table 3 above, compared with their corresponding comparative examples, the sheet-like acoustic reinforced composite materials provided in Examples 1-5 of this invention did not experience a decrease in acoustic performance after high-temperature and high-humidity treatment, indicating that these sheet-like acoustic reinforced composite materials all possess stable performance. Furthermore, the sheet-like acoustic reinforced composite materials provided in Comparative Examples 1-5 also did not experience a significant decrease in acoustic performance after high-temperature and high-humidity treatment, indicating that these sheet-like acoustic reinforced composite materials also possess stable performance; however, their acoustic performance (acoustic performance in Table 1 and acoustic efficiency in Table 2) is inferior to that of their corresponding examples. In addition, since maleic anhydride-modified polypropylene fibers were used in Comparative Examples 8 and 9, the acoustic performance of the sheet-like acoustic reinforced composite materials obtained from them did not experience a significant decrease after high-temperature and high-humidity treatment, indicating that these sheet-like acoustic reinforced composite materials also possess stable performance; however, their acoustic performance (acoustic performance in Table 1 and acoustic efficiency in Table 2) is inferior to that of their corresponding examples.

[0232] As can be seen from Table 3 above, the sheet-like acoustic reinforced composite materials provided in Examples 6-8 of this invention did not experience a decrease in acoustic performance after high-temperature and high-humidity treatment, indicating that these sheet-like acoustic reinforced composite materials all possess stable properties. However, the sheet-like acoustic reinforced composite materials provided in Comparative Examples 6 and 7 showed a significant decrease in acoustic performance after high-temperature and high-humidity treatment, which fully demonstrates that the hydrophilic modified synthetic fibers play an important role in the high-temperature and high-humidity storage (Δf'HTHR) of the sheet-like acoustic reinforced composite materials.

[0233] Test Example 3

[0234] In this test example, a high-definition digital microscope was used to obtain the surface morphology of the sheet-like acoustic reinforcement composite materials provided in Examples 1, 3-4, and 6-8 of this invention, respectively. The experimental results are as follows: Figures 1-6 As shown. From Figures 1-6 It is clearly visible that the sheet-like acoustic reinforcement composite material provided in this embodiment of the invention contains a three-dimensional network structure of interwoven fibrous materials, and porous powder particles are precipitated on the surface of the fibrous materials and in the three-dimensional network structure by the action of a precipitation aid. Meanwhile, from... Figures 1-6 It can also be seen that the surface of the sheet-like acoustic reinforced composite material provided in the embodiments of the present invention has a rich porous structure; and the higher the proportion of the dry mass of the porous powder material particles in the sheet-like acoustic reinforced composite material, the more obvious the porous powder material particles attached therein by the precipitation aid can be observed in the three-dimensional network structure.

[0235] Test Example 4

[0236] This test example performed SEM analysis on the sheet-like acoustic reinforcement composite material provided in Example 2 of the present invention. The obtained SEM image is shown below. Figure 7 As shown. From Figure 7 As can be seen from the above, the sheet-like acoustic reinforcement composite material provided in Example 2 of the present invention contains a large number of porous structures and has a high porosity. These porous structures are three-dimensional network structures formed by interwoven fibrous materials. Therefore, it can be reasonably inferred that the sheet-like acoustic reinforcement composite materials prepared in other embodiments of the present invention also contain a large number of porous structures and have a high porosity.

[0237] Comparative Test Example 1

[0238] In this comparative test, 40.0 mg, 30.0 mg, 17.75 mg, 7.0 mg, and 9.31 mg of commercially available acoustic enhancement particles (average particle size of 420 μm) were accurately weighed. Then, the acoustic performance Δf0 and high temperature and high humidity storage Δf'HTHR of the commercially available acoustic enhancement particles were tested according to the same test method as in Test Example 1 and Test Example 2. The results are shown in Table 4 below.

[0239] Table 4 Test results of commercially available acoustic reinforcement particles

[0240]

[0241]

[0242] A comparison of the experimental data in Tables 1, 3, and 4 shows that the acoustic properties Δf0 and high-temperature and high-humidity storage Δf'HTHR of the sheet-like acoustic reinforced composite materials provided in Examples 1-8 of this invention are significantly better than those of existing commercially available acoustic reinforced particles.

[0243] 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, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. An acoustically reinforced composite material, characterized in that, The acoustically reinforced composite material is made of interwoven fibrous materials with a three-dimensional network structure inside. The surface of the fibrous materials is coated with porous powder material by a precipitation aid. Based on the total weight of the acoustically reinforced composite material as 100%, the oven-dry mass percentage of the fibrous material is 19.50-85.95%, the oven-dry mass percentage of the porous powder material is 14.0-80.0%, and the oven-dry mass percentage of the precipitation aid is 0.05-0.5%. The diameter or width of the fibrous material ranges from 8 to 70 μm, and the aspect ratio ranges from 8 to 500. The fibrous material includes organic fibers, which include hydrophilic natural fibers and chemically synthesized fibers, wherein the oven-dry mass ratio of the hydrophilic natural fibers to the chemically synthesized fibers is 100-80:0-20. The chemically synthesized fibers include hydrophilically modified chemically synthesized fibers.

2. The acoustically reinforced composite material according to claim 1, characterized in that, The oven-dry weight ratio of hydrophilic natural fibers to chemically synthesized fibers is 100-95:0-5.

3. The acoustically reinforced composite material according to claim 1 or 2, characterized in that, The chemically synthesized fiber is an unmodified chemically synthesized fiber and a hydrophilically modified chemically synthesized fiber obtained by hydrophilically modifying an unmodified chemically synthesized fiber, or a hydrophilically modified chemically synthesized fiber obtained by hydrophilically modifying an unmodified chemically synthesized fiber. The unmodified chemical synthetic fibers include one or a combination of several of the following: polypropylene fiber, polyamide fiber, polyethylene fiber, polyester fiber, polylactic acid fiber, polyetheretherketone fiber, polyphenylene sulfide fiber, and polyacrylonitrile fiber.

4. The acoustically reinforced composite material according to claim 3, characterized in that, The chemically synthesized fiber is a hydrophilic modified chemically synthesized fiber.

5. The acoustically reinforced composite material according to claim 1 or 2, characterized in that, The cross-sectional shape of the chemically synthesized fiber includes circular, flat, or irregular shapes, among which irregular shapes include cross structure, core-sheath structure, triangular structure, clover structure, king-shaped structure, Y-shaped structure, or hollow structure.

6. The acoustically reinforced composite material according to claim 1 or 2, characterized in that, The hydrophilic natural fiber includes one or more of plant fibers, regenerated cellulose fibers and bacterial fibers, wherein the oven-dry weight ratio of plant fibers, regenerated cellulose fibers and bacterial fibers is 100-60:0-30:0-10.

7. The acoustically reinforced composite material according to claim 6, characterized in that, The oven-dry weight ratio of plant fiber, regenerated cellulose fiber and bacterial fiber is 100-85:0-10:0-5.

8. The acoustically reinforced composite material according to claim 6, 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 30-70 μm. The ratio of the oven-dry weight of coarse plant fibers to fine plant fibers is 100-0:0-100.

9. The acoustically reinforced composite material according to claim 8, characterized in that, The ratio of the oven-dry weight of coarse plant fibers to fine plant fibers is 100-30:0-70.

10. The acoustically reinforced composite material according to claim 6, characterized in that, The aspect ratio of the plant fiber is 8-150.

11. The acoustically reinforced composite material according to claim 6, characterized in that, The plant fiber is a fibrous material made from natural plants, wherein the natural plants include one or a combination of several of the following: coniferous wood, broadleaf wood, hemp, bamboo, rice straw, sugarcane bagasse, reeds, and cotton.

12. The acoustically reinforced composite material according to claim 6, characterized in that, The regenerated cellulose fiber includes one or a combination of several of the following: viscose fiber, modal fiber, lyocell fiber, acetate fiber, cuprammonium fiber, and Tencel fiber.

13. The acoustically reinforced composite material according to claim 6, 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 Diplococcus.

14. The acoustically reinforced composite material according to claim 1, characterized in that, The porous powder material includes one or a combination of several of the following: zeolite molecular sieve, activated silica, activated carbon, porous calcium carbonate, porous calcium silicate, alumina, hydrogel, and aerogel.

15. The acoustically reinforced composite material according to claim 14, characterized in that, The zeolite molecular sieve has a particle size of 0.5-10 μm and includes micropores with a pore size of 0.3-0.7 nm and mesopores with a pore size of 10-30 nm.

16. The acoustically reinforced composite material according to claim 14 or 15, characterized in that, The zeolite molecular sieve includes one or a combination of several of the following: MFI structured molecular sieve, FER structured molecular sieve, CHA structured molecular sieve, MEL structured molecular sieve, TON structured molecular sieve, and MTT structured molecular sieve.

17. The acoustically reinforced composite material according to claim 1, characterized in that, The precipitation aid includes one or a combination of several of the following: polyacrylamide, starch, polyethyleneimine, polyimide, and guar gum.

18. The acoustically reinforced composite material according to claim 1, characterized in that, The basis weight range of the acoustically reinforced composite material is 50-1200 g / m³. 2 .

19. The acoustically reinforced composite material according to claim 1, characterized in that, The acoustically reinforced composite material can be in sheet, block, or irregular shape.

20. A method for manufacturing the acoustically reinforced composite material according to any one of claims 1-19, characterized in that, The manufacturing method includes: Step 1: Disperse the fibrous material, porous powder material and precipitation aid in water respectively to obtain the fibrous material dispersion, the porous powder material dispersion and the precipitation aid dispersion; Step 2: Add the porous powder material dispersion to the fibrous material dispersion and mix evenly. Then add the precipitating agent dispersion and mix evenly to make the fibrous materials intertwine and at the same time precipitate the porous powder material on the surface of the fibrous materials. Step 3: Filter the mixture obtained in Step 2 to obtain the precursor material; Step 4: The precursor material is then dried to obtain the acoustically reinforced composite material.

21. A loudspeaker, comprising one or more acoustic sensors and one or more housings, wherein the one or more acoustic sensors and the one or more housings are combined to form a rear cavity of the loudspeaker, characterized in that, The rear cavity of the loudspeaker is fitted with the acoustically reinforced composite material according to any one of claims 1-19.

22. An electronic device, characterized in that, The electronic device is equipped with an acoustically reinforced composite material according to any one of claims 1-19 in the rear cavity of the speaker.

23. The electronic device according to claim 22, characterized in that, The electronic devices include smartphones, TWS earphones, headphones, smart glasses, smartwatches, VR devices, AR devices, tablets, or thin and light laptops.

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