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

Abstract

This invention provides an acoustic enhancement material, its manufacturing method, and a loudspeaker and electronic device. The acoustic enhancement material is composed of interwoven fibrous materials with a three-dimensional network structure. Porous powder material is attached to the surface of the fibrous materials through a precipitation aid. The fibrous materials include one or a combination of inorganic fibers, plant fibers, and composite chemical fibers. The acoustic enhancement material provided by this invention exhibits high acoustic performance and high strength. After drop testing, the surface of the acoustic enhancement material does not shed powder, and it adheres firmly to double-sided adhesive without internal separation. This is crucial for ensuring the long-term stable operation of the acoustic enhancement material within the loudspeaker cavity.

Description

Technical Field

[0001] This invention relates to an acoustic enhancement material and its manufacturing method, as well as 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 acoustic enhancement 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] To address the aforementioned shortcomings and deficiencies, an objective of this invention is to provide an acoustic enhancement material. The acoustic enhancement material provided by this invention is more porous and has higher porosity, which is beneficial for porous powder materials to exert their acoustic effects.

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

[0007] Another object of the present invention is to provide a loudspeaker in which the acoustic enhancement 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 acoustic enhancement 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 acoustic enhancement material, wherein the acoustic enhancement material is composed of interwoven fibrous materials with a three-dimensional network structure inside, and porous powder material is attached (precipitated) to the surface of the fibrous materials by a precipitation aid;

[0010] The fibrous material includes one or a combination of several of inorganic fibers, plant fibers, and composite chemical fibers.

[0011] In this invention, fibrous materials interweave to form an acoustic reinforcement material, and a three-dimensional network structure is formed inside the acoustic reinforcement material during the interweaving process; since porous powder material is attached to the surface of the fibrous materials 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 acoustic reinforcement material.

[0012] As a specific embodiment of the acoustic enhancement material described above in this invention, the fibrous material comprises 19.50-85.95% of the total weight of the acoustic enhancement material (100%), the porous powder material comprises 14.0-80.0% of the dry weight, preferably 50.0-70.0%, and the precipitation aid comprises 0.05-0.5% of the dry weight.

[0013] In one specific embodiment of the acoustic enhancement material described above in this invention, the diameter or width of the fibrous material ranges from 3 to 70 μm, and the aspect ratio ranges from 8 to 500. 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.

[0014] As a specific embodiment of the acoustic enhancement material described above in this invention, the inorganic fiber has a diameter or width ranging from 3 to 45 μm and an aspect ratio of 10 to 500.

[0015] As a specific embodiment of the acoustic enhancement material described above in this invention, the inorganic fiber includes one or a combination of several of the following: basalt fiber, glass fiber, quartz fiber, asbestos fiber, volcanic rock fiber, metal fiber, alumina fiber, and carbon fiber.

[0016] The inorganic fibers used in this invention are characterized by not absorbing or absorbing very little moisture, and remaining undeformed in aqueous systems. Due to their stiffness, high rigidity, and non-deformation properties, these inorganic fibers play a crucial role in maintaining the shape and stiffness of acoustic reinforcement materials.

[0017] As a specific embodiment of the acoustic enhancement material described above in this invention, the diameter or width of the plant fiber ranges from 8 to 70 μm, and the aspect ratio ranges from 8 to 150.

[0018] As a specific embodiment of the acoustic enhancement material described above in this invention, the moisture absorption ratio of the plant fiber is 16.0-31.5%, preferably 20.0-31.5%.

[0019] As a specific embodiment of the acoustic enhancement 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.

[0020] The plant fibers selected in this invention contain a large number of hydrophilic groups, such as hydroxyl and carboxyl groups. When the acoustic reinforcement material containing plant fibers is used in the rear cavity, water molecules in the air will be preferentially absorbed and fixed by the plant fibers, thereby reducing the performance degradation of porous powder materials caused by water molecules and significantly improving the service life of the acoustic reinforcement material in the rear cavity.

[0021] The plant fiber selected in this invention is mainly composed of cellulose, with trace amounts of hemicellulose and lignin. To improve the acoustic performance of the acoustic reinforcement material, increasing the mass percentage of porous powder material with acoustic enhancement function is the primary solution. The porous powder material particles used in this invention are inorganic, and their size is much smaller than that of fibrous materials, resulting in no significant interaction between them in an aqueous system. To address this issue, this invention adds a small amount of a precipitating agent. This precipitating agent is adhesive and can fix the porous powder material particles to the surface of the fibrous material through adhesion, essentially fixing the porous powder material particles into the three-dimensional network structure inside the acoustic reinforcement material. However, under external forces (such as continuous vibration or collision), the porous powder material particles risk falling off the surface of the acoustic reinforcement material, i.e., shedding. Therefore, increasing the specific surface area of ​​the plant fiber and improving the bonding sites between the plant fiber and the porous powder material particles is of great significance. While some plant fibers have sufficient surface bonding sites, others have smoother, denser surfaces. Therefore, certain physical and chemical methods, such as grinding and hammering, are needed to break down the primary fiber walls without significantly altering the fiber's aspect ratio. This disperses the fiber bundle into individual fibers, significantly increasing the specific surface area and exposing more hydrophilic groups. The increased specific surface area of ​​plant fibers not only enhances their bonding sites with porous powder particles, reducing the risk of dust shedding from acoustic materials, but also improves the bond strength between fibers, thereby enhancing the internal bonding strength of the acoustic reinforcement material.

[0022] Since the distribution of fine fibers, roughness, and specific surface area of ​​the plant fibers selected in this invention are difficult to measure, this invention indirectly uses the "moisture absorption ratio" as a comprehensive indicator for evaluating the specific surface area of ​​plant fibers. The more individual fibers dispersed in the fiber bundles on the surface of a plant fiber, and the larger its specific surface area, the stronger its ability to bind water.

[0023] In this invention, the "hygroscopic ratio" of plant fibers is measured using the following method:

[0024] Weigh a certain mass (about 2.0g) of plant fiber and add it to pure water at 20℃. Adjust the dry mass concentration of the plant fiber to about 0.5%, and then shear and disperse it to disperse the plant fiber into individual fibers.

[0025] After the plant fibers are completely dispersed into individual fibers, the dispersion of the plant fibers is filtered through a 200-mesh sieve. Under the action of natural gravity, water that does not interact with the plant fibers will be lost. After standing for 10 minutes, the wet plant fibers are collected and weighed, and recorded as X. X includes the dry mass of the plant fibers and the mass of water absorbed by them.

[0026] A mass of wet plant fiber X is transferred to an oven at 110°C and dried to constant weight. The mass at this point is recorded as Y, where Y is the oven-dry mass of the plant fiber. The mass of pure water absorbed by the wet plant fiber X is recorded as Z, where Z = XY.

[0027] Calculate the moisture absorption ratio of plant fibers according to the following formula 1;

[0028] Moisture absorption ratio = (Z / Y) × 100% Formula 1.

[0029] For the same type of plant fiber, the higher the moisture absorption ratio, the stronger its ability to absorb water, which means that its specific surface area is larger and the more fine fibers are exposed on the surface. In the three-dimensional network structure of acoustic reinforcement materials, this helps to reduce the risk of powder shedding and improve the internal bonding strength of the material.

[0030] 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.

[0031] As a specific embodiment of the acoustic enhancement material described above in this invention, the fibrous material may be a combination of fibrous materials with different diameters or widths and different aspect ratios.

[0032] Preferably, the fibrous material is selected from a combination of two or more fibrous materials with different diameters or widths and different aspect ratios.

[0033] As a specific embodiment of the acoustic enhancement material described above in this invention, the diameter or width of the chemical fibers of the composite component ranges from 10 to 70 μm, and the aspect ratio ranges from 10 to 200.

[0034] As a specific embodiment of the acoustic enhancement material described above in this invention, the chemical fibers of the composite components include one or a combination of several of the chemical fibers of composite components such as core-sheath structure, parallel structure, and island structure.

[0035] As a specific embodiment of the acoustic enhancement material described above in this invention, the chemical fibers of the core-skin composite component include a core layer and a skin layer covering the core layer, and the material of the skin layer includes chemical fibers with a melting point not higher than 140°C, and the material of the core layer includes chemical fibers with a melting point not lower than 150°C.

[0036] As a specific embodiment of the acoustic enhancement material described above in this invention, the core layer comprises ordinary polyester fiber and / or polypropylene fiber, and the sheath layer comprises polyethylene fiber and / or modified polyester fiber.

[0037] 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 of polyethylene fiber, or a chemical fiber with a core layer of polypropylene fiber and a sheath of polyethylene fiber, or a chemical fiber with a core layer of ordinary polyester fiber and a sheath of modified polyester fiber, etc.

[0038] The melting point of the ordinary polyester fiber is 250-265℃, the melting point of the polyethylene fiber is 110-130℃, the melting point of the polypropylene fiber is 150-170℃, and the melting point of the modified polyester fiber is lower, at 100-140℃.

[0039] Under conditions where the temperature is not lower than the melting point of the sheath layer contained in the composite chemical fiber, the sheath layer of the composite chemical fiber begins to melt. After melting, it can bond with other fibers or porous powder material particles in contact with it. At this time, the core layer does not melt and maintains the original structure and morphology of the composite chemical fiber. Therefore, the rational use of composite chemical fibers can significantly improve the internal bonding strength of acoustic reinforcement materials and reduce the risk of powder shedding. At the same time, since the core fiber does not melt, the composite chemical fiber will not shrink significantly, thus not reducing the thickness of the acoustic reinforcement material, nor changing the morphology and fluffiness of the acoustic reinforcement material.

[0040] As a specific embodiment of the acoustic enhancement material described above in this invention, 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.

[0041] In one specific embodiment of the acoustic reinforcement material described above in this invention, the chemical fibers with a melting point not higher than 140°C include polyethylene fibers and / or modified polyester fibers, and the chemical fibers with a melting point not lower than 150°C include ordinary polyester fibers and / or polypropylene fibers. Specifically, the ordinary polyester fibers have a melting point of 250-265°C, the polyethylene fibers have a melting point of 110-130°C, the polypropylene fibers have a melting point of 150-170°C, and the modified polyester fibers have a lower melting point of 100-140°C.

[0042] The chemical fiber with island structure composite component used in this invention, namely island fiber, is a polymer dispersed in another polymer. In the cross section of the fiber, the dispersed phase is in the state of "island", while the parent phase is equivalent to "sea". From the cross section of the island fiber, one component is surrounded by another component in a fine and dispersed state, as if there are many islands in the sea.

[0043] As a specific embodiment of the acoustic enhancement material described above in this 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.

[0044] Preferably, the matrix material includes polyethylene fiber and / or modified polyester fiber, and the dispersed phase material includes ordinary polyester fiber and / or polypropylene fiber.

[0045] When the chemical fibers of the parallel structure composite component and the island structure composite component are used at temperatures between the melting points of the two chemical components with different melting points, the low-melting-point chemical fiber melts and acts as a binder, while the high-melting-point chemical fiber does not melt, maintaining the structure and morphology of the composite component fibers. Thus, through the synergistic effect of the two chemical components with different melting points, the internal bonding strength of the acoustic reinforcement material can be significantly improved, the risk of powder shedding can be reduced, and the thickness of the acoustic reinforcement material will not be reduced, nor will the morphology and fluffiness of the acoustic reinforcement material be changed.

[0046] The chemical fibers used in this invention, including the core-sheath composite component, the parallel structure composite component (i.e., parallel composite fiber), and the island-island composite component (i.e., island fiber), are all existing conventional products and can be obtained commercially.

[0047] In one specific embodiment of the acoustic enhancement material described above in this invention, the oven-dry mass ratio of plant fiber to chemical fiber of the composite component is 98-60:2-40.

[0048] 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 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, hydrogel, and aerogel.

[0049] As a specific embodiment of the acoustic enhancement 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.

[0050] In order to further improve the acoustic enhancement effect of the acoustic enhancement material, as a specific embodiment of the acoustic enhancement 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.

[0051] As a specific embodiment of the acoustic enhancement 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.

[0052] As a specific embodiment of the acoustic enhancement material described above in this invention, the basis weight of the acoustic enhancement material ranges from 50 to 1200 g / m³. 2 .

[0053] As a specific embodiment of the acoustic enhancement material described above in this invention, the shape of the acoustic enhancement material includes sheet-like, block-like, or irregular shapes. When applying this acoustic enhancement material, those skilled in the art can reasonably select an acoustic enhancement material of a suitable shape as needed. Alternatively, those skilled in the art can also obtain an acoustic enhancement material of the target shape by combining the manufacturing method provided by this invention with existing conventional methods.

[0054] On the other hand, the present invention also provides a method for manufacturing the acoustic enhancement material described above, wherein the manufacturing method includes:

[0055] 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;

[0056] 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.

[0057] Step 3: Filter the mixture obtained in Step 2 to obtain the precursor material;

[0058] Step 4: The precursor material is then dried to obtain the acoustic enhancement material.

[0059] In a specific embodiment of the manufacturing method described above, when the fibrous material comprises composite chemical fibers, the manufacturing method further includes:

[0060] Step 5: Under conditions where the temperature is not lower than the melting point of the sheath layer contained in the chemical fiber of the composite component, the acoustic reinforcement material is subjected to high-temperature treatment so that the sheath layer in the chemical fiber of the composite component melts while the core layer does not melt. After the sheath layer melts, it plays a bonding role. After the heat preservation is completed, it is cooled to room temperature to obtain a high-strength and high-efficiency acoustic reinforcement material.

[0061] In this invention, the temperature of the high-temperature treatment needs to be selected based on the melting point of the skin. In some embodiments of this invention, 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 a holding time of 5-20 minutes.

[0062] This invention produces acoustic reinforcement materials through an integral molding method. Integral molding refers to the process in which fibrous materials with porous powder attached to the surface interweave to form a three-dimensional network structure during the molding process of acoustic reinforcement materials. It can also be called co-molding.

[0063] As a specific embodiment of the manufacturing method described above in this invention, in step one, with the total weight of the fibrous material dispersion being 100%, the oven-dry mass concentration of the fibrous material in the fibrous material dispersion is 0.2-4%.

[0064] As a specific embodiment of the manufacturing method described above in this invention, in step one, with the total weight of the porous powder material dispersion liquid as 100%, the oven-dry mass concentration of the porous powder material in the porous powder material dispersion liquid is 1-50%.

[0065] As a specific embodiment of the preparation method described above in this invention, in step one, based on the total weight of the precipitating agent dispersion as 100%, the oven-dry mass concentration of the precipitating agent in the precipitating agent dispersion is 0.01-4.00%.

[0066] 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.

[0067] 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.

[0068] In a 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%. During the filtration process, water is directly filtered through the filter screen, while the fibrous material with porous powder material deposited on the surface gradually accumulates, and the fibrous material interweaves to build a three-dimensional network structure.

[0069] 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.

[0070] The present invention can control the shape of the obtained acoustic reinforcement 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 acoustic reinforcement material. That is, the present invention can control the thickness of the acoustic reinforcement material through filtration. Alternatively, different shaped molds can be selected for filtration as needed to obtain irregularly shaped acoustic reinforcement materials. Of course, the blocky or irregularly shaped acoustic reinforcement material obtained after drying can also be cut to obtain an irregularly shaped acoustic reinforcement material.

[0071] 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.

[0072] 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 acoustic enhancement material described above is assembled in the rear cavity of the loudspeaker.

[0073] In another aspect, the present invention also provides an electronic device in which the acoustic enhancement material described above is assembled in the rear cavity of the speaker of the electronic device.

[0074] 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.

[0075] Compared with the prior art, the beneficial technical effects achieved by the present invention include:

[0076] 1. High-efficiency mass production: This invention enables the high-efficiency mass production of acoustic reinforcement materials without the need for special equipment, raw materials, or chemicals.

[0077] 2. Arbitrary cutting: The acoustic enhancement material provided by this invention 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.

[0078] 3. High acoustic performance: The acoustic reinforcement 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 acoustic reinforcement particles on the market.

[0079] 4. High strength: The acoustic reinforcement material provided by this invention has high strength. After drop testing, the surface of the acoustic reinforcement material does not shed powder, and it adheres firmly to the double-sided adhesive without any separation of the acoustic reinforcement material from the inside. This is an important condition for ensuring the long-term stable operation of the acoustic reinforcement material in the speaker cavity. Attached Figure Description

[0080] 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.

[0081] Figure 1 This is a schematic diagram of the morphology of hydroxyl-containing coniferous wood fibers used in Example 2 of the present invention.

[0082] Figure 2 This is a schematic diagram of the morphology of coniferous wood fibers used in Embodiment 4 of the present invention.

[0083] Figure 3 This is a schematic diagram of the morphology of the broadleaf wood fiber used in Embodiment 4 of the present invention.

[0084] Figure 4 This is a schematic diagram of the morphology of coniferous wood fibers used in Embodiment 5 of the present invention.

[0085] Figure 5 This is a schematic diagram of the morphology of the broadleaf wood fiber used in Embodiment 5 of the present invention.

[0086] Figure 6 This is a schematic diagram of the morphology of coniferous wood fibers used in Comparative Example 2.

[0087] Figure 7 This is a schematic diagram of the morphology of the coniferous wood fibers used in Comparative Example 5.

[0088] Figure 8 This is a schematic diagram of the morphology of the hardwood fibers used in Comparative Example 5.

[0089] Figure 9 This is a SEM image of the sheet-like acoustic reinforcement material provided in Embodiment 2 of the present invention.

[0090] Figure 10 The surface morphology of the sheet-like acoustic reinforcement material provided in Example 5 of the present invention after a drop test, as shown in Test Example 3 of the present invention.

[0091] Figure 11 The surface morphology of the sheet-like acoustic reinforcement material provided in Comparative Example 5 after a drop test is shown in Test Example 3 of the present invention. Detailed Implementation

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] In the examples, the "hygroscopic ratio" of the plant fibers was measured using the following method:

[0100] Weigh a certain mass (about 2.0g) of plant fiber and add it to pure water at 20℃. Adjust the dry mass concentration of the plant fiber to about 0.5%, and then shear and disperse it to disperse the plant fiber into individual fibers.

[0101] After the plant fibers are completely dispersed into individual fibers, the dispersion of the plant fibers is filtered through a 200-mesh sieve. Under the action of natural gravity, water that does not interact with the plant fibers will be lost. After standing for 10 minutes, the wet plant fibers are collected and weighed, and recorded as X. X includes the dry mass of the plant fibers and the mass of water absorbed by them.

[0102] A mass of wet plant fiber X is transferred to an oven at 110°C and dried to constant weight. The mass at this point is recorded as Y, where Y is the oven-dry mass of the plant fiber. The mass of pure water absorbed by the wet plant fiber X is recorded as Z, where Z = XY.

[0103] Calculate the moisture absorption ratio of plant fibers according to the following formula 1;

[0104] Moisture absorption ratio = (Z / Y) × 100% Formula 1.

[0105] In the embodiments, the oven-dry mass percentage of porous powder material in the sheet-like acoustic reinforcement material can be measured using the following method:

[0106] After drying the sheet-like acoustic reinforcement material to constant weight in an oven at 110℃, its mass is accurately weighed and recorded as A;

[0107] Accurately weigh the mass of the dried crucible, denoted as B. Place the sheet-like acoustic reinforcement material of mass A into the dried crucible, then place the crucible in a high-temperature muffle furnace and set the heating program to 0.5℃ / min. Heat from room temperature to 525℃ and hold for 120 minutes, then cool to room temperature.

[0108] The total weight of the crucible and the porous powder material with acoustic enhancement function inside the crucible is denoted as C;

[0109] After a sheet-like acoustic reinforcement material of mass A is calcined at high temperature, the mass of the porous powder material with acoustic reinforcement function contained therein is denoted as D. Then D = CB.

[0110] In a sheet-like acoustic reinforcement material with mass A, the mass percentage of porous powder material with acoustic reinforcement function is denoted as E. Then, E = (D / A) × 100% (Formula 2).

[0111] The strength of sheet-like acoustic reinforcement materials is one of the important indicators for evaluating them and is also a crucial guarantee for their application stability. In the test examples of this invention, the strength of the sheet-like acoustic reinforcement materials was measured according to the following method:

[0112] The sheet-like acoustic reinforcement material is cut into a certain size (e.g., a 10*10mm square) and then attached to the inner wall of the metal test fixture with double-sided tape. The metal test fixture is a cuboid with a mass of 220g.

[0113] Adjust the height of the automatic drop test machine to 180cm. With the ground being marble, automatically drop the metal test fixture with sheet acoustic reinforcement material attached onto the marble floor from a height of 180cm.

[0114] All six sides of the metal testing fixture need to undergo drop tests. For example, if each side is dropped 6 times, then a total of 36 drop tests are required. In some special cases, each side is required to be dropped 12 times, then a total of 72 drop tests are required.

[0115] After the drop test, observe whether the surface of the sheet-like acoustic reinforcement material exhibits ① the phenomenon of porous powder material with acoustic reinforcement function falling off and ② the phenomenon of internal separation and falling off of the sheet-like acoustic reinforcement material.

[0116] Among them, ① is used to evaluate the bonding strength between porous powder material and three-dimensional network structure in sheet-like acoustic reinforcement material. If no loosening of porous powder material is observed after drop test, it indicates that the bonding strength between porous powder material and three-dimensional network structure in sheet-like acoustic reinforcement material is high.

[0117] ② Used to evaluate the internal bonding strength of sheet-like acoustic reinforcement materials. Because sheet-like acoustic reinforcement materials have a certain thickness and mass, they may separate after a drop test due to insufficient internal bonding strength. If no separation or detachment is observed within the sheet-like acoustic reinforcement material after the drop test, it indicates that its internal bonding strength is high.

[0118] Example 1

[0119] This embodiment provides a sheet-like acoustic reinforcement material with a basis weight of 800 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforcement material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by a precipitation aid.

[0120] The fibrous material is composed of plant fibers and composite chemical fibers, 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 oven-dry weight ratio of 14.55% and a moisture absorption ratio of 29.5%.

[0121] The chemical fiber of the composite component is a core-sheath structure composite chemical fiber (Ningbo Dafeng Chemical Fiber Co., Ltd., model VF-450LM), including a core layer and a sheath layer covering the core layer. The core layer is ordinary polyester fiber (melting point 250-265℃), and the sheath layer is modified polyester fiber (melting point 110℃). The diameter of the chemical fiber of the composite component is 50μm, and it is cut to an aspect ratio of 40, with an oven-dry weight percentage of 5.0%.

[0122] The precipitation aid is starch with an average relative molecular weight of 550,000;

[0123] 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.

[0124] Based on the total weight of the sheet-like acoustic reinforcement material as 100%, the oven-dry mass percentage of the fibrous material is 19.55%, the oven-dry mass percentage of the porous powder material is 80.0%, and the oven-dry mass percentage of the precipitation aid is 0.45%.

[0125] In this embodiment, the sheet-like acoustic reinforcement material is prepared by a method including the following specific steps:

[0126] 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.

[0127] Among them, the fibrous material dispersion has an oven-dry mass concentration of 2.0%, the porous powder material dispersion has an oven-dry mass concentration of 20%, and the precipitation aid dispersion has an oven-dry mass concentration of 0.02%.

[0128] 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.

[0129] Step 3: Filter the mixture obtained in Step 2 to obtain a sheet material with a water content of 70 wt%.

[0130] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After drying, a sheet acoustic reinforcement material is obtained.

[0131] Step 5: Place the sheet-like acoustic reinforcement material described above into a forced-air drying oven and maintain the temperature inside the oven at 140℃ for 8 minutes to perform high-temperature treatment on the sheet-like acoustic reinforcement material. This process melts the outer layer of the chemical fiber in the composite component while keeping the core layer intact. The melted outer layer acts as a binder. After the heat treatment is completed, cool the sheet-like acoustic reinforcement material to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic reinforcement material. The oven-dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic reinforcement material is measured using the method described above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0132] Example 2

[0133] This embodiment provides a sheet-like acoustic reinforcement material with a basis weight of 800 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforcement material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by a precipitation aid.

[0134] The fibrous material is composed of plant fibers and composite chemical fibers. The plant fibers are hydroxyl-containing coniferous wood fibers with an average width of 36 μm and an aspect ratio of 70, accounting for 29.60% of their oven-dry weight and having a moisture absorption ratio of 22.5%. The morphology of these hydroxyl-containing coniferous wood fibers is as follows: Figure 1 As shown, from Figure 1 As can be seen from the above, the surface of the hydroxyl-containing coniferous wood fiber used in this embodiment has a large number of fine fibers.

[0135] The chemical fiber of the composite component is a core-sheath structure composite chemical fiber (Ningbo Dafeng Chemical Fiber Co., Ltd., model VF-450LM), including a core layer and a sheath layer covering the core layer. The core layer is ordinary polyester fiber (melting point 250-265℃), and the sheath layer is modified polyester fiber (melting point 110℃). The diameter of the chemical fiber of the composite component is 50μm, and it is cut to an aspect ratio of 40, with an oven-dry weight percentage of 10.0%.

[0136] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0137] 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.

[0138] Based on the total weight of the sheet-like acoustic reinforcement 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 0.40%.

[0139] In this embodiment, the sheet-like acoustic reinforcement material is prepared by a method including the following specific steps:

[0140] 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.

[0141] Among them, the fibrous material dispersion has an oven-dry mass concentration of 2.0%, the porous powder material dispersion has an oven-dry mass concentration of 20%, and the precipitation aid dispersion has an oven-dry mass concentration of 0.02%.

[0142] 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.

[0143] Step 3: Filter the mixture obtained in Step 2 to obtain a sheet material with a water content of 70 wt%.

[0144] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After drying, a sheet acoustic reinforcement material is obtained.

[0145] Step 5: Place the sheet-like acoustic reinforcement material described above into a forced-air drying oven and maintain the temperature inside the oven at 140℃ for 8 minutes to perform high-temperature treatment on the sheet-like acoustic reinforcement material. This process melts the outer layer of the chemical fiber in the composite component while keeping the core layer intact. The melted outer layer acts as a binder. After the heat treatment is completed, cool the sheet-like acoustic reinforcement material to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic reinforcement material. The oven-dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic reinforcement material is measured using the method described above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0146] Example 3

[0147] This embodiment provides a sheet-like acoustic reinforcement material with a basis weight of 800 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforcement material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by a precipitation aid.

[0148] The fibrous material is composed of organic fibrous material and inorganic fibrous material. The organic fibrous material is composed of plant fiber and chemical fiber of composite components. The plant fiber is hydroxyl-containing coniferous wood fiber with an average width of 45 μm, an aspect ratio of 70, an oven-dry weight ratio of 40%, and a moisture absorption ratio of 22.5%.

[0149] The chemical fibers of the composite component are chemical fibers of a parallel structure composite component, including high melting point fibers and low melting point fibers. The high melting point fibers are ordinary polyester fibers (melting point of 250-265℃), and the low melting point fibers are polyethylene fibers (melting point of 120℃). The diameter of the chemical fibers of the composite component is 50μm, and they are cut to an aspect ratio of 40, with an oven-dry weight percentage of 18.0%.

[0150] The inorganic fibrous material is glass fiber with an average diameter of 11 μm and an aspect ratio of 280, and its oven-dry mass accounts for 1.65%.

[0151] The precipitation aid is guar gum with an average relative molecular weight of 1.6 million;

[0152] 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.

[0153] Based on the total weight of the sheet-like acoustic reinforcement material as 100%, the oven-dry mass percentage of the fibrous material is 59.65%, the oven-dry mass percentage of the porous powder material is 40.0%, and the oven-dry mass percentage of the precipitation aid is 0.35%.

[0154] In this embodiment, the sheet-like acoustic reinforcement material is prepared by a method including the following specific steps:

[0155] 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.

[0156] Among them, the fibrous material dispersion has an oven-dry mass concentration of 2.0%, the porous powder material dispersion has an oven-dry mass concentration of 20%, and the precipitation aid dispersion has an oven-dry mass concentration of 0.02%.

[0157] 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.

[0158] Step 3: Filter the mixture obtained in Step 2 to obtain a sheet material with a water content of 70 wt%.

[0159] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After drying, a sheet acoustic reinforcement material is obtained.

[0160] Step 5: Place the sheet-like acoustic reinforcement material described above into a forced-air drying oven and maintain the temperature inside the oven at 140℃ for 8 minutes to perform high-temperature treatment on the sheet-like acoustic reinforcement material. This process melts the outer layer of the chemical fiber in the composite component while keeping the core layer intact. The melted outer layer acts as a binder. After the heat treatment is completed, cool the sheet-like acoustic reinforcement material to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic reinforcement material. The oven-dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic reinforcement material is measured using the method described above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0161] Example 4

[0162] This embodiment provides a sheet-like acoustic reinforcement material with a basis weight of 800 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforcement material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by a precipitation aid.

[0163] The fibrous material is composed of 100% organic fibrous material, wherein the oven-dry weight of hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70 accounts for 21.55%, with a moisture absorption ratio of 29.5%; and the oven-dry weight of hydroxyl-containing hardwood fibers with an average width of 17 μm and an aspect ratio of 65 accounts for 8.0%, with a moisture absorption ratio of 27.5%. The morphology of the coniferous and hardwood fibers is as follows: Figure 2 and Figure 3 As shown, from Figure 2 and Figure 3 As can be seen from the above, the surface of the plant fibers used in this embodiment has a large number of fine fibers.

[0164] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0165] 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.

[0166] Based on the total weight of the sheet-like acoustic reinforcement material as 100%, the oven-dry mass percentage of the fibrous material is 29.55%, the oven-dry mass percentage of the porous powder material is 70.0%, and the oven-dry mass percentage of the precipitation aid is 0.45%.

[0167] In this embodiment, the sheet-like acoustic reinforcement material is prepared by a method including the following specific steps:

[0168] 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.

[0169] Among them, the fibrous material dispersion has an oven-dry mass concentration of 2.0%, the porous powder material dispersion has an oven-dry mass concentration of 20%, and the precipitation aid dispersion has an oven-dry mass concentration of 0.02%.

[0170] 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.

[0171] Step 3: Filter the mixture obtained in Step 2 to obtain a sheet material with a water content of 70 wt%.

[0172] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After drying, sheet acoustic reinforcement material is obtained. The oven-dry mass ratio of porous powder material in the high-strength and high-efficiency sheet acoustic reinforcement 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.

[0173] Example 5

[0174] This embodiment provides a sheet-like acoustic reinforcement material with a basis weight of 800 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforcement material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by a precipitation aid.

[0175] The fibrous material is composed of 100% organic fibrous material, wherein the oven-dry weight of hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70 accounts for 29.60%, with a moisture absorption ratio of 22.5%; and the oven-dry weight of hydroxyl-containing hardwood fibers with an average width of 17 μm and an aspect ratio of 65 accounts for 10%, with a moisture absorption ratio of 25.5%. The morphologies of the coniferous and hardwood fibers are as follows: Figure 4 and Figure 5 As shown, from Figure 4 and Figure 5 As can be seen from the above, the surface of the plant fibers used in this embodiment has a large number of fine fibers.

[0176] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0177] 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.

[0178] Based on the total weight of the sheet-like acoustic reinforcement 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 0.40%.

[0179] In this embodiment, the sheet-like acoustic reinforcement material is prepared by a method including the following specific steps:

[0180] 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.

[0181] Among them, the fibrous material dispersion has an oven-dry mass concentration of 2.0%, the porous powder material dispersion has an oven-dry mass concentration of 20%, and the precipitation aid dispersion has an oven-dry mass concentration of 0.02%.

[0182] 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.

[0183] Step 3: Filter the mixture obtained in Step 2 to obtain a sheet material with a water content of 70 wt%.

[0184] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After drying, sheet acoustic reinforcement material is obtained. The oven-dry mass ratio of porous powder material in the high-strength and high-efficiency sheet acoustic reinforcement 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.

[0185] Example 6

[0186] This embodiment provides a sheet-like acoustic reinforcement material with a basis weight of 800 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforcement material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by a precipitation aid.

[0187] The fibrous material is composed of organic and inorganic fibrous materials. Among them, the oven-dry weight of hydroxyl-containing coniferous wood fibers with an average width of 45 μm and an aspect ratio of 70 accounts for 30%, and the moisture absorption ratio is 22.5%; the oven-dry weight of hydroxyl-containing hardwood fibers with an average width of 17 μm and an aspect ratio of 65 accounts for 18%, and the moisture absorption ratio is 17.5%; and the oven-dry weight of glass fibers with an average diameter of 11 μm and an aspect ratio of 280 accounts for 1.65%.

[0188] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0189] 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.

[0190] Based on the total weight of the sheet-like acoustic reinforcement material as 100%, the oven-dry mass percentage of the fibrous material is 49.65%, the oven-dry mass percentage of the porous powder material is 50.0%, and the oven-dry mass percentage of the precipitation aid is 0.35%.

[0191] In this embodiment, the sheet-like acoustic reinforcement material is prepared by a method including the following specific steps:

[0192] 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.

[0193] Among them, the fibrous material dispersion has an oven-dry mass concentration of 2.0%, the porous powder material dispersion has an oven-dry mass concentration of 20%, and the precipitation aid dispersion has an oven-dry mass concentration of 0.02%.

[0194] 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.

[0195] Step 3: Filter the mixture obtained in Step 2 to obtain a sheet material with a water content of 70 wt%.

[0196] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After drying, sheet acoustic reinforcement material is obtained. The oven-dry mass ratio of porous powder material in the high-strength and high-efficiency sheet acoustic reinforcement 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.

[0197] Example 7

[0198] This embodiment provides a sheet-like acoustic reinforcement material with a basis weight of 800 g / m³. 2 It is composed of interwoven fibrous materials, and the sheet-like acoustic reinforcement material has a three-dimensional network structure inside. The surface of the fibrous material is coated with porous powder material by a precipitation aid.

[0199] The fibrous material is composed of inorganic fibrous material and composite chemical fibers, wherein the inorganic fibrous material is glass fiber with an average diameter of 11 μm and an aspect ratio of 280, and its dry weight accounts for 14.55%.

[0200] The chemical fiber of the composite component is a core-sheath structure composite chemical fiber (Ningbo Dafeng Chemical Fiber Co., Ltd., model VF-450LM), including a core layer and a sheath layer covering the core layer. The core layer is ordinary polyester fiber (melting point 250-265℃), and the sheath layer is modified polyester fiber (melting point 110℃). The diameter of the chemical fiber of the composite component is 50μm, and it is cut to an aspect ratio of 40, with an oven-dry weight percentage of 5.0%.

[0201] The precipitation aid is polyacrylamide with a molecular weight of 15 million;

[0202] 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.

[0203] Based on the total weight of the sheet-like acoustic reinforcement material as 100%, the oven-dry mass percentage of the fibrous material is 19.55%, the oven-dry mass percentage of the porous powder material is 80.0%, and the oven-dry mass percentage of the precipitation aid is 0.45%.

[0204] In this embodiment, the sheet-like acoustic reinforcement material is prepared by a method including the following specific steps:

[0205] 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.

[0206] Among them, the fibrous material dispersion has an oven-dry mass concentration of 2.0%, the porous powder material dispersion has an oven-dry mass concentration of 20%, and the precipitation aid dispersion has an oven-dry mass concentration of 0.02%.

[0207] 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.

[0208] Step 3: Filter the mixture obtained in Step 2 to obtain a sheet material with a water content of 70 wt%.

[0209] Step 4: The sheet material is then subjected to forced-air drying at a temperature of 110°C for 120 minutes. After drying, a sheet acoustic reinforcement material is obtained.

[0210] Step 5: Place the sheet-like acoustic reinforcement material described above into a forced-air drying oven and maintain the temperature inside the oven at 140℃ for 8 minutes to perform high-temperature treatment on the sheet-like acoustic reinforcement material. This process melts the outer layer of the chemical fiber in the composite component while keeping the core layer intact. The melted outer layer acts as a binder. After the heat treatment is completed, cool the sheet-like acoustic reinforcement material to room temperature to obtain a high-strength and high-efficiency sheet-like acoustic reinforcement material. The oven-dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-like acoustic reinforcement material is measured using the method described above, and compared with the amount of porous powder material in the formula. The comparison results show that the two are consistent.

[0211] Comparative Example 1

[0212] This comparative example provides an acoustic enhancement particle, which is a commercially available conventional product with an average particle size of 420 μm.

[0213] Comparative Example 2

[0214] This comparative example provides a sheet-like acoustic reinforcement material, which differs from Example 2 in that:

[0215] The moisture absorption rate of coniferous wood fiber is 14.0%, and it uses ordinary polyester fiber, rather than a composite chemical fiber. The morphology of this coniferous wood fiber is as follows: Figure 6 As shown, from Figure 6 As can be seen, the softwood fibers with a moisture absorption ratio of 14.0% used in this comparative example have very few fine surface fibers.

[0216] Comparative Example 3

[0217] This comparative example provides a sheet-like acoustic reinforcement material, which differs from Example 2 in that:

[0218] The moisture absorption ratio of coniferous wood fiber is 14.0%.

[0219] Comparative Example 4

[0220] This comparative example provides a sheet-like acoustic reinforcement material, which differs from Example 2 in that:

[0221] It uses ordinary polyester fibers, rather than chemical fibers with composite components.

[0222] Comparative Example 5

[0223] This comparative example provides a sheet-like acoustic reinforcement material, which differs from Example 5 only in that:

[0224] The moisture absorption ratio of coniferous wood fiber is 14.0%, and that of hardwood fiber is 15.0%. The morphologies of the coniferous and hardwood fibers are as follows: Figure 7 and Figure 8 As shown, from Figure 7 and Figure 8 As can be seen from this comparative example, there are very few fine surface fibers of the plant fibers used.

[0225] Comparative Example 6

[0226] This comparative example provides a sheet-like acoustic reinforcement material, which differs from Example 5 only in that:

[0227] The moisture absorption ratio of coniferous wood fiber is 32.0%, while that of broadleaf wood fiber is 33.0%.

[0228] Test Example 1

[0229] This test example demonstrates SEM analysis of the sheet-like acoustic enhancement material provided in Example 2 of this invention. The obtained SEM images are shown below. Figure 9 As shown. From Figure 9 As can be seen from the above, the sheet-like acoustic reinforcement material provided in Embodiment 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 materials prepared in other embodiments of the present invention also contain a large number of porous structures and have a high porosity.

[0230] Test Example 2

[0231] In this test example, the sheet-like acoustic reinforcement materials provided in Examples 1-7 and Comparative Examples 2-6 were first cut into 10*10mm sizes and weighed. Then, the resonant frequency shift value Δf0 of the sheet-like acoustic reinforcement materials was tested according to part 7.4 of the group standard "Porous Sound Absorbing Particles for Miniature Loudspeakers" (standard number: T / CECA 78-2022). The specific results are shown in Table 1 below.

[0232] Table 1. Acoustic performance data of sheet-like acoustic reinforcement materials in Examples 1-7 and Comparative Examples 2-6.

[0233]

[0234]

[0235] After calculation, the sheet-like acoustic reinforcement materials obtained in Examples 1-7 and Comparative Examples 2-6 were cut into 10*10mm sizes. The oven-dry mass of molecular sieve in each sheet-like acoustic reinforcement material was 64.0mg, 48.0mg, 32.0mg, 56.0mg, 48.0mg, 40.0mg, 64.0mg, 48.0mg, 48.0mg, 48.0mg, 48.0mg, and 48.0mg, respectively.

[0236] The acoustic efficiency per unit mass of sheet acoustic reinforcement material was then calculated using the formula shown below, and the resulting acoustic efficiency data are shown in Table 2.

[0237] Acoustic efficiency = Δf0 / (ocean-dry mass of molecular sieve), unit: Hz / mg.

[0238] Table 2. Acoustic efficiency data of sheet-like acoustic reinforcement materials in Examples 1-7 and Comparative Examples 2-6.

[0239]

[0240]

[0241] As can be seen from the experimental data in Tables 1 and 2 above, the sheet-like acoustic enhancement materials provided in Examples 1-7 of the present invention all have high-efficiency acoustic properties.

[0242] In this test example, acoustic reinforcing particles provided in Comparative Example 1 were accurately weighed at concentrations of 64.0 mg, 56.0 mg, 48.0 mg, 40.0 mg, and 32.0 mg, respectively. The resonant frequency shift value Δf0 of the acoustic reinforcing particles was tested according to section 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 3 below.

[0243] Table 3. Acoustic performance and acoustic efficiency data of commercially available conventional acoustic enhancement particles.

[0244]

[0245] A comparison of the experimental data in Tables 1-2 and 3 shows that the acoustic performance of the sheet-like acoustic reinforcement materials provided in Examples 1-7 of this invention is significantly better than that of commercially available conventional acoustic reinforcement particles.

[0246] Comparing the experimental data in Tables 1-2 and 3, it can be seen that the acoustic properties of the sheet-like acoustic reinforcement materials provided in Comparative Examples 2, 3, and 4 are the same as those in Example 2 of this invention. This is mainly because the addition of either chemical fibers or ordinary polyester fibers to the composite components has virtually no impact on the acoustic properties of the sheet-like acoustic reinforcement materials. The main difference between the sheet-like acoustic reinforcement materials provided in these examples and comparative examples is that the sheet-like acoustic reinforcement material provided in Example 2 of this invention has high internal bonding strength; while the internal bonding strength of the sheet-like acoustic reinforcement materials provided in Comparative Examples 2, 3, and 4 is far lower than that in Example 2. For details, please refer to Table 4 and the related explanations in Table 4.

[0247] For the sheet-like acoustic reinforcement materials provided in Examples 2 and 5 of the present invention, the proportion of the molecular sieve in oven-dry mass is the same, which is 60.0%. However, the acoustic performance of the sheet-like acoustic reinforcement material provided in Example 2 is slightly better than that in Example 5. The reason is that chemical fibers with a core-sheath structure composite component and an oven-dry mass ratio of 10.0% were added in Example 2.

[0248] For the sheet-like acoustic reinforcement materials provided in Examples 1 and 7 of this invention, the dry mass percentage of molecular sieve is the same, both being 80%. However, the acoustic performance of the sheet-like acoustic reinforcement material provided in Example 1 is slightly better than that in Example 7. The reason for this is that Example 1 added 14.55% of coniferous wood fiber by dry mass, while Example 7 added 14.55% of glass fiber by dry mass. As is well known, the density of glass fiber is much greater than that of coniferous wood fiber. Therefore, the density of the sheet-like acoustic reinforcement material obtained in Example 7 is also greater than that of the sheet-like acoustic reinforcement material obtained in Example 1, and correspondingly, its acoustic performance is slightly lower than that of the sheet-like acoustic reinforcement material provided in Example 1.

[0249] For the sheet-like acoustic reinforcement materials provided in Example 5 and Comparative Example 5 of this invention, the molecular sieve dry mass ratio is the same, both being 60%. Although the moisture absorption ratio of the coniferous wood fiber used in Comparative Example 5 is only 14.0%, and that of the broadleaf wood fiber is only 15.0%, the acoustic performance of the sheet-like acoustic reinforcement materials provided in Comparative Example 5 and Example 5 is basically the same. This is because: when the moisture absorption ratio of the fibrous material is small, its specific surface area is also small, which mainly restricts the bonding between the porous powder material and the fibrous material, thereby reducing the strength of the sheet-like acoustic reinforcement material (as shown in the experimental data in Test Example 3 below), while having little impact on the acoustic performance of the sheet-like acoustic reinforcement material.

[0250] For the sheet-like acoustic reinforcement materials provided in Embodiment 5 and Comparative Example 6 of the present invention, the molecular sieve dry mass ratio is the same, both being 60%. However, since the moisture absorption ratio of the coniferous wood fiber used in Comparative Example 6 is 32.0% and that of the broad-leaved wood fiber is 33.0%, the area of ​​inter-bonding between the fibrous materials used in Comparative Example 6 is too large, resulting in insufficient porosity in the sheet-like acoustic reinforcement material, making its acoustic performance far inferior to that of the sheet-like acoustic reinforcement material provided in Embodiment 5.

[0251] Test Example 3

[0252] In this test example, the sheet acoustic reinforcement materials provided in Example 2, Comparative Example 2, Example 5, and Comparative Example 5 were first cut into 10*10mm squares. These squares were then attached to the inner wall of a 220g metal test fixture using double-sided adhesive. The height of the automatic drop test machine was then adjusted to 180cm, and the floor was marble. The metal test fixture with the sheet acoustic reinforcement materials attached was automatically dropped from a height of 180cm onto the marble floor. Each of the six sides of the metal test fixture was dropped six times, for a total of 36 drops.

[0253] After 36 drop tests, the sheet-like acoustic reinforcement material provided in Embodiments 2 and 5 of the present invention remained intact and adhered to the inner wall of the test fixture. Figure 10 The image shows the sheet-like acoustic reinforcement material provided in Embodiment 5 of the present invention after being dropped (image after being torn apart in layers). The image shows that the sheet-like acoustic reinforcement material is intact and has not separated.

[0254] After 36 drop tests, the sheet-like acoustic reinforcement materials provided in Comparative Examples 2 and 5 separated internally, with a portion adhering to the inner wall of the test fixture, exposing the internal fibrous and porous powder materials. Figure 11 The image shown is of the sheet acoustic reinforcement material provided in Comparative Example 5 after being torn apart in layers. The image shows that the internal structure of the sheet acoustic reinforcement material has separated, indicating that the internal bonding strength of the sheet acoustic reinforcement material is insufficient.

[0255] Comparing the drop test results of the sheet acoustic reinforcement materials provided in Example 2 and Comparative Example 2, and Example 5 and Comparative Example 5 of the present invention, it can be seen that controlling the moisture absorption ratio of the organic fibrous material in the sheet acoustic reinforcement material within a specific range of 16.0-31.5% and using chemical fibers with composite components can significantly improve the strength of the sheet acoustic reinforcement material and ensure its long-term stable operation in the speaker cavity.

[0256] Test Example 4

[0257] In this test example, the sheet-like acoustic reinforcement materials provided in Example 2 and Comparative Examples 2-4 were first cut into 10*10mm squares, and then attached to the inner wall of a 220g metal test fixture using double-sided adhesive. The height of the automatic drop test machine was then adjusted to 180cm, and the floor was marble. The metal test fixture with the attached sheet-like acoustic reinforcement materials was automatically dropped from a height of 180cm onto the marble floor. All six sides of the metal test fixture were dropped the same number of times until all the sheet-like acoustic reinforcement materials separated. The total number of drops resulting in the separation of the sheet-like acoustic reinforcement materials provided in Example 2 and Comparative Examples 2-4 is shown in Table 4 below.

[0258] Table 4. Total number of drops resulting in separation of the sheet-like acoustic reinforcement materials in Examples 2 and Comparative Examples 2-4

[0259] Total number of falls Example 2 120 Comparative Example 2 6 Comparative Example 3 48 Comparative Example 4 72

[0260] As shown in Table 4, the sheet-like acoustic reinforcement material provided in Example 2 only exhibited complete separation after a total of 120 drops. Compared to Example 2, the moisture absorption ratio of the coniferous wood fiber used in Comparative Example 3 was substandard, and Comparative Example 4 used ordinary polyester fiber instead of composite chemical fiber. Although the total number of drops corresponding to the complete separation of the sheet-like acoustic reinforcement materials provided in Comparative Examples 3 and 4 was relatively high, it was significantly lower than the total number of drops corresponding to Example 2. For Comparative Example 2, where the moisture absorption ratio of the coniferous wood fiber was substandard and ordinary polyester fiber was used instead of composite chemical fiber, the total number of drops corresponding to the complete separation of the sheet-like acoustic reinforcement material provided in Comparative Example 2 was only 6, significantly lower than Comparative Examples 3-4 and Example 2.

[0261] The above experimental results also show that controlling the moisture absorption ratio of the organic fibrous material in the sheet acoustic reinforcement material within a specific range of 16.0-31.5% and using chemical fibers with composite components can significantly improve the strength of the sheet acoustic reinforcement material and ensure its long-term stable operation in the loudspeaker cavity.

[0262] 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 enhancing material, characterized in that, The acoustic enhancement material is composed of interwoven fibrous materials with a three-dimensional network structure inside, and porous powder material is attached to the surface of the fibrous materials by a precipitation aid. The fibrous material includes plant fibers; or, the fibrous material includes plant fibers and at least one selected from inorganic fibers and chemical fibers of composite components. The moisture absorption ratio of the plant fiber is 16.0-31.5%.

2. The acoustically enhancing material of claim 1, wherein, Based on the total weight of the acoustic reinforcement 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%.

3. The acoustically enhancing material of claim 2, wherein, The porous powder material has an oven-dry mass ratio of 50.0-70.0%.

4. The acoustically enhancing material of claim 1, wherein, The diameter or width of the fibrous material ranges from 3 to 70 μm, and the aspect ratio ranges from 8 to 500.

5. The acoustically enhancing material of claim 4, wherein, The inorganic fibers have a diameter or width ranging from 3 to 45 μm and an aspect ratio of 10 to 500.

6. The acoustic enhancement material according to any one of claims 1-5, characterized in that, The inorganic fibers include one or a combination of several of the following: basalt fiber, glass fiber, quartz fiber, asbestos fiber, volcanic rock fiber, metal fiber, alumina fiber, and carbon fiber.

7. The acoustically enhancing material of claim 4, wherein, The diameter or width of the plant fiber ranges from 8 to 70 μm, and the aspect ratio ranges from 8 to 150.

8. The acoustically enhancing material according to any of claims 1-4, 7, wherein, The moisture absorption ratio of the plant fiber is 20.0-31.5%.

9. The acoustically enhancing material of claim 8, wherein, 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.

10. The acoustically enhancing material of claim 4, wherein, The diameter or width of the chemical fibers in the composite component ranges from 10 to 70 μm, and the aspect ratio ranges from 10 to 200.

11. The acoustically enhancing material according to any of claims 1-4, 10, wherein, The composite chemical fibers include one or a combination of several of the following: core-sheath structure, parallel structure, and island structure composite chemical fibers.

12. The acoustically enhancing material of claim 11, wherein, Chemical fibers with parallel structural composite components include chemical fibers with a melting point not higher than 140℃ and chemical fibers with a melting point not lower than 150℃.

13. The acoustic enhancement material according to claim 12, characterized in that, Chemical fibers with a melting point not higher than 140°C include polyethylene fibers and / or modified polyester fibers, and chemical fibers with a melting point not lower than 150°C include ordinary polyester fibers and / or polypropylene fibers.

14. The acoustically enhancing material of claim 11, wherein, The matrix material of the chemical fiber in the island-structured composite component includes chemical fibers with a melting point not higher than 140℃, and the dispersed phase material includes chemical fibers with a melting point not lower than 150℃.

15. The acoustically enhancing material of claim 14, wherein, The matrix material includes polyethylene fiber and / or modified polyester fiber, and the dispersed phase material includes ordinary polyester fiber and / or polypropylene fiber.

16. The acoustically enhancing material of claim 11, wherein, The chemical fiber of the core-sheath composite component includes a core layer and a sheath layer covering the core layer, wherein the material of the sheath layer includes chemical fibers with a melting point not higher than 140°C, and the material of the core layer includes chemical fibers with a melting point not lower than 150°C.

17. The acoustically enhancing material of claim 16, wherein, The core layer comprises ordinary polyester fibers and / or polypropylene fibers, and the sheath comprises polyethylene fibers and / or modified polyester fibers.

18. The acoustically enhancing material according to any of claims 1-4, wherein, The oven-dry weight ratio of plant fiber to chemical fiber in the composite composition is 98-60:2-40.

19. The acoustically enhancing material according to claim 1, wherein, 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.

20. The acoustic enhancement material according to claim 19, 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.

21. The acoustically enhancing material according to claim 19 or 20, wherein, 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.

22. The acoustically enhancing material according to claim 1, wherein, The precipitation aid includes one or a combination of several of the following: polyacrylamide, starch, polyethyleneimine, polyimide, and guar gum.

23. The acoustically enhancing material according to any of claims 1-5, wherein, The acoustic enhancement material has a grammage in the range of 50-1200 g / m 2 .

24. The acoustically enhancing material according to any of claims 1-5, wherein, The acoustic enhancement material may be in the form of sheets, blocks, or irregular shapes.

25. A method for manufacturing the acoustic enhancement material according to any one of claims 1-24, 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 acoustic enhancement material.

26. The method of manufacturing according to claim 25, wherein, When the fibrous material comprises composite chemical fibers, the manufacturing method further includes: Step 5: The acoustic reinforcement material is subjected to high-temperature treatment at a temperature not lower than the melting point of the sheath layer contained in the composite chemical fiber, so that the sheath layer in the composite chemical fiber melts while the core layer does not melt.

27. 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 acoustic enhancement material according to any one of claims 1-24.

28. An electronic device, comprising: The electronic device is equipped with the acoustic enhancement material according to any one of claims 1-24 in the rear cavity of the speaker.

29. The electronic device of claim 28, wherein, The electronic devices include smartphones, TWS earphones, headphones, smart glasses, smartwatches, VR devices, AR devices, tablets, or thin and light laptops.

Images