CN117230636A

CN117230636A - Acoustic enhancement material, manufacturing method thereof, loudspeaker and electronic equipment

Info

Publication number: CN117230636A
Application number: CN202311194809.8A
Authority: CN
Inventors: 郭明波; 请求不公布姓名; 张磊; 马院红
Original assignee: Zhenjiang Best New Material Co ltd
Current assignee: Zhenjiang Best New Material Co ltd
Priority date: 2023-09-15
Filing date: 2023-09-15
Publication date: 2023-12-15

Abstract

The invention provides an acoustic enhancement material, a manufacturing method thereof, a loudspeaker and electronic equipment, wherein the acoustic enhancement material is formed by interweaving fibrous materials, a three-dimensional network structure is arranged in the acoustic enhancement material, and a porous powder material is attached to the surface of the fibrous materials through a precipitation auxiliary agent; wherein the fibrous material comprises one or a combination of several of inorganic fibers, plant fibers and chemical fibers of composite components. The acoustic enhancement material provided by the invention has high-efficiency acoustic performance and high strength, and through drop test, the surface of the acoustic enhancement material is not subjected to powder falling, and the acoustic enhancement material is firm with double-sided adhesive tape, and the phenomenon of internal separation of the acoustic enhancement material is avoided, so that the acoustic enhancement material is an important condition for ensuring long-term stable operation of the acoustic enhancement material in a cavity of a loudspeaker.

Description

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

Technical Field

The invention relates to an acoustic enhancement material, a manufacturing method thereof, a loudspeaker and electronic equipment, and belongs to the technical field of materials, in particular to the technical field of electronic acoustic materials.

Background

Electronic products such as mobile phones, tablets, notebook computers and the like are lighter and thinner, so that resonant cavities of speaker system components used by the electronic products are smaller and smaller. As is well known, the resonant cavity of smaller and smaller speakers causes the resonant frequency to increase and the low-frequency sound pressure sensitivity to decrease, and the audio quality requirements of consumers on electronic products such as mobile phones, tablets, notebook computers and the like are higher and higher. In order to solve the contradiction between the two, acoustic reinforcing materials have been developed.

The porous powder material capable of efficiently adsorbing and releasing air molecules is prepared into sound-absorbing particles with average particle size of 200-800 mu m by a molding technology, and the sound-absorbing particles are filled in the cavity of the loudspeaker, so that the method is a conventional method for improving the audio quality of the small-cavity loudspeaker. However, this method also has certain drawbacks, such as: first, the prior art generally fills the sound absorbing particles into the cavity of the speaker by canning, but the canning process is difficult. In particular, the space of the resonant cavity of the micro-speaker is very small, the space height is in the range of hundreds of micrometers, and the quantitative filling of sound-absorbing particles in the resonant cavity is very narrow, which is almost impossible to accomplish. However, the narrow resonant cavity tends to have the greatest effect on low frequencies, and is also the most desirable structure to be filled with sound absorbing material. Secondly, in the speaker working process, traditional sound absorption particles vibrate at high frequency in the cavity and collide with the inner wall of the cavity, so that the phenomenon of breakage and crushing of the sound absorption particles is caused, and the speaker monomer is damaged. In addition, in the filling process at the present stage, sound absorbing particles can only fill about 80% of the back cavity volume of the speaker module, and the back cavity space cannot be fully utilized.

Therefore, providing a novel acoustic enhancement material, a manufacturing method thereof, a speaker and an electronic device have become technical problems to be solved in the art.

Disclosure of Invention

In order to solve the above-described drawbacks and disadvantages, an object of the present invention is to provide an acoustic enhancement material. The acoustic enhancement material provided by the invention is fluffier and high in porosity, and is beneficial to the porous powder material to exert the acoustic effect.

It is a further object of the present invention to provide a method of making the above-described acoustic enhancement material.

It is a further object of the invention to provide a loudspeaker with a rear chamber fitted with an acoustic enhancement material as described above.

It is a further object of the invention to provide an electronic device with a speaker rear cavity fitted with an acoustic enhancement material as described above.

In order to achieve the above object, in one aspect, the present invention provides an acoustic reinforcement material, wherein the acoustic reinforcement material is formed by interweaving fibrous materials, the interior of the acoustic reinforcement material has a three-dimensional network structure, and the surface of the fibrous materials is adhered (precipitated) with a porous powder material through a precipitation aid;

wherein the fibrous material comprises one or a combination of several of inorganic fibers, plant fibers and chemical fibers of composite components.

In the invention, the fibrous materials are interwoven with each other to form an acoustic enhancement material, and a three-dimensional network structure is formed inside the acoustic enhancement material in the interweaving process; the surface of the fibrous material is adhered with the porous powder material through the precipitation aid, which is equivalent to the porous powder material being also adhered to the surface of the three-dimensional network structure and the acoustic enhancement material.

As a specific embodiment of the above-mentioned acoustic enhancement material according to the present invention, the fibrous material has an absolute dry mass ratio of 19.50 to 85.95%, the porous powder material has an absolute dry mass ratio of 14.0 to 80.0%, preferably 50.0 to 70.0%, and the precipitation aid has an absolute dry mass ratio of 0.05 to 0.5% based on 100% of the total weight of the acoustic enhancement material.

As a specific embodiment of the above-described acoustic reinforcement material of the present invention, wherein the fibrous material has a diameter or width ranging from 3 to 70 μm and an aspect ratio ranging from 8 to 500. In the present invention, "aspect ratio" refers to the ratio of the length to the diameter of a fibrous material, and in some particular fibrous materials, "aspect ratio" is also understood to be the ratio of the length to the width.

As a specific embodiment of the above-described acoustic reinforcement material of the present invention, wherein the inorganic fibers have a diameter or width in the range of 3 to 45 μm and an aspect ratio of 10 to 500.

As a specific embodiment of the above acoustic reinforcement material according to the present invention, the inorganic fiber includes one or a combination of several of basalt fiber, glass fiber, quartz fiber, asbestos fiber, volcanic fiber, metal fiber, alumina fiber, carbon fiber, and the like.

The inorganic fiber used in the invention is characterized in that: no or very little moisture is absorbed, and no deformation in the aqueous system environment occurs. The inorganic fiber has the characteristics of stiffness, high rigidity, no deformation and the like, so that the inorganic fiber plays an important role in maintaining and keeping the shape, the stiffness and the like of the acoustic enhancement material.

As a specific embodiment of the above-mentioned acoustic reinforcement material according to the present invention, the plant fiber has a diameter or width in the range of 8-70 μm and an aspect ratio in the range of 8-150.

As a specific embodiment of the above-mentioned acoustic reinforcement material of the present invention, the moisture absorption ratio of the plant fiber is 16.0 to 31.5%, preferably 20.0 to 31.5%.

As a specific embodiment of the above-mentioned acoustic reinforcement material according to the present invention, the plant fiber is a fibrous material prepared from natural plants, wherein the natural plants include one or a combination of several of conifer, hardwood, hemp, bamboo, straw, bagasse, reed, cotton, and the like.

The plant fiber selected by the invention contains more hydrophilic groups, for example: hydroxyl, carboxyl and the like, and the water molecules in the air can be preferentially absorbed and fixed by the plant fibers in the actual use process of the acoustic enhancement material containing the plant fibers, so that the performance attenuation of the porous powder material caused by the water molecules is reduced, and the service life of the acoustic enhancement material in the rear cavity is fully prolonged.

The main component of the plant fiber selected by the invention is cellulose, and also contains little hemicellulose and lignin. In order to improve the acoustic performance of the acoustic enhancement material, the mass percentage of the porous powder material with the acoustic enhancement function in the acoustic enhancement material is a primary scheme. The porous powder material particles used in the invention are inorganic substances, and meanwhile, the size of the porous powder material particles is far smaller than that of fibrous materials, and no obvious acting force exists between the porous powder material particles and the fibrous materials in an aqueous system. In order to solve the problems, a small amount of precipitation aid is added, the precipitation aid has viscosity, and porous powder material particles can be fixed on the surface of a fibrous material through adhesion, namely, the porous powder material particles are fixed in a three-dimensional network structure inside an acoustic enhancement material through the precipitation aid. However, under the action of external forces (such as continuous vibration, collision, etc.), the porous powder material particles risk falling off the surface of the acoustic reinforcement material, i.e., falling off the powder. Therefore, the specific surface area of the plant fiber is increased, and the binding sites of the plant fiber and the porous powder material particles are improved, so that the method has very important significance. The surface binding sites of part of plant fibers meet the requirements, but the surfaces of part of plant fibers are smooth and compact, and certain physical and chemical methods such as polishing, hammering and the like are needed, so that the primary walls on the surfaces of the plant fibers are destroyed under the condition that the length-diameter ratio of the plant fibers is not destroyed or the length-diameter ratio is rarely destroyed, and fiber bundles are dispersed into single fibers, thereby remarkably improving the specific surface area of the plant fibers and exposing more hydrophilic groups. The specific surface area of the plant fiber is increased, so that the binding sites between the plant fiber and the porous powder material particles are improved, the risk of powder falling of the acoustic material is reduced, and the binding fastness between fibers is improved, thereby improving the internal binding strength of the acoustic enhancement material.

As the distribution condition, the roughness degree, the specific surface area and the like of the surface fine fibers of the plant fibers selected by the invention are not easy to measure, the invention indirectly adopts the parameter of the moisture absorption ratio as the comprehensive index for evaluating the specific surface area and the like of the plant fibers. The more the fiber bundles on the surface of the plant fiber are dispersed into single fibers, the larger the specific surface area is, and the stronger the water binding capacity is.

In the present invention, the "moisture absorption ratio" of the plant fiber is measured as follows:

weighing plant fiber with certain mass (about 2.0 g), adding the plant fiber into pure water at 20 ℃, adjusting the absolute dry mass concentration of the plant fiber to about 0.5%, and shearing and dispersing to disperse the plant fiber into single fiber;

after the plant fibers are completely dispersed into single fibers, filtering the dispersion liquid of the plant fibers by using a 200-mesh screen, and under the action of natural gravity, water which does not interact with the plant fibers is lost, standing for 10min, collecting wet plant fibers, namely the mass of the wet plant fibers, and marking the mass as X, wherein the X comprises the absolute dry mass of the plant fibers and the mass of water absorbed by the wet plant fibers;

transferring wet plant fiber with mass of X into an oven at 110 ℃, drying to constant weight, recording the mass at the moment, and recording Y, wherein Y is the absolute dry mass of the plant fiber, and the mass of pure water absorbed by the wet plant fiber with mass of X is Z, wherein Z=X-Y;

Calculating the moisture absorption ratio of the plant fiber according to the following formula 1;

moisture absorption ratio= (Z/Y) ×100% formula 1.

For the same plant fiber, the larger the moisture absorption ratio is, the stronger the water absorption capacity is, which means that the larger the specific surface area is and the more tiny fibers are exposed on the surface, the powder falling risk is reduced in the three-dimensional network structure of the acoustic enhancement material, and the internal bonding strength of the material is improved.

The method for preparing the plant fiber from the natural plant is a conventional method, and the preparation method can be reasonably adjusted according to the characteristics of the natural plant, the performances of the target plant fiber and the like. For example, in some embodiments of the invention, the method of making comprises: removing lignin and most hemicellulose in natural plants, and obtaining the fibrous material mainly containing cellulose, namely the plant fiber, after bleaching treatment or without bleaching treatment.

As an embodiment of the above acoustic reinforcement material according to the present invention, the fibrous material may be selected from a combination of fibrous materials having different diameters or widths and different aspect ratios;

preferably, the fibrous material is selected from a combination of two or more fibrous materials of different diameters or widths and different aspect ratios.

As a specific embodiment of the above-described acoustic reinforcement material of the present invention, wherein the chemical fibers of the composite component have a diameter or width in the range of 10 to 70 μm and an aspect ratio in the range of 10 to 200.

As a specific embodiment of the above acoustic reinforcement material according to the present invention, the chemical fiber of the composite component includes one or a combination of several of the chemical fibers of the composite component such as a sheath-core structure, a parallel structure, and an island-in-the-sea structure.

In an embodiment of the invention, the chemical fiber of the composite component of the sheath-core structure includes a core layer and a sheath layer covering the core layer, the sheath layer includes chemical fiber with a melting point not higher than 140 ℃, and the core layer includes chemical fiber with a melting point not lower than 150 ℃.

As a specific embodiment of the above acoustic reinforcement material of the present invention, wherein the core layer includes a common polyester fiber and/or a polypropylene fiber, and the skin layer includes a polyethylene fiber and/or a modified polyester fiber.

In some embodiments of the present invention, the chemical fibers of the composite component may be chemical fibers in which the core layer is a common polyester fiber, the sheath layer is a polyethylene fiber, or may be chemical fibers in which the core layer is a polypropylene fiber, the sheath layer is a polyethylene fiber, and the core layer is a common polyester fiber, the sheath layer is a modified polyester fiber, or the like;

Wherein the melting point of the common 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 and is 100-140 ℃.

Under the condition that the temperature is not lower than the melting point of the cortex contained in the chemical fiber of the composite component, the cortex in the chemical fiber of the composite component begins to melt, and after the melting, the cortex can be bonded with other fiber or porous powder material particles contacted with the cortex; in this case, the core layer does not melt and retains the original structure and morphology of the chemical fiber of the composite component. Therefore, the reasonable utilization of the chemical fibers of the composite components can obviously improve the internal bonding strength of the acoustic enhancement material and reduce the risk of powder falling; meanwhile, as the core layer fiber is not melted, the chemical fiber of the composite component is not obviously contracted, so that the thickness of the acoustic enhancement material is not reduced, and the shape, the fluffy state and the like of the acoustic enhancement material are not changed.

As a specific embodiment of the above-described acoustic reinforcement material of the present invention, wherein the chemical fibers of the side-by-side structural composite component include chemical fibers having a melting point of not higher than 140 ℃ and chemical fibers having a melting point of not lower than 150 ℃.

As a specific embodiment of the above-described acoustic reinforcement material of the present invention, wherein the chemical fiber having a melting point of not higher than 140 ℃ includes polyethylene fiber and/or modified polyester fiber, and the chemical fiber having a melting point of not lower than 150 ℃ includes common polyester fiber and/or polypropylene fiber. Wherein the melting point of the common 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 and is 100-140 ℃.

The chemical fiber of the sea-island structure composite component used in the present invention, i.e., a sea-island fiber, is a fiber in which one polymer is dispersed in another polymer, the dispersed phase is in an "island" state in the cross section of the fiber, and the matrix corresponds to "sea", and one component is surrounded by another component in a fine and dispersed state as if there were many islands in the sea, as seen from the cross section of the sea-island fiber.

In one embodiment of the above-mentioned acoustic enhancement material of the present invention, the matrix material of the chemical fiber of the sea-island structure composite component includes chemical fiber having a melting point not higher than 140 ℃, and the material of the dispersed phase includes chemical fiber having a melting point not lower than 150 ℃;

Preferably, the matrix material comprises polyethylene fibers and/or modified polyester fibers, and the disperse phase material comprises common polyester fibers and/or polypropylene fibers.

When the use temperature of the chemical fibers of the parallel structure composite component and the chemical fibers of the island structure composite component is between the melting point temperatures of two different melting point chemical components contained in the parallel structure composite component, the low-melting point chemical fibers are melted to play a role in bonding, while the high-melting point chemical fibers are not melted to maintain the structure and the shape of the composite component fibers, so that the internal bonding strength of the acoustic enhancement material can be obviously improved through the synergistic effect of the two different melting point chemical components, the risk of powder dropping is reduced, the thickness of the acoustic enhancement material is not reduced, the shape and the fluffy state of the acoustic enhancement material are not changed, and the like.

The chemical fiber of the sheath-core structure composite component, the chemical fiber of the parallel structure composite component (namely, the parallel composite fiber) and the chemical fiber of the sea-island structure composite component (namely, the sea-island fiber) used in the invention are all conventional products and can be obtained commercially.

As a specific embodiment of the above acoustic reinforcement material of the present invention, the absolute dry mass ratio of the plant fiber to the chemical fiber of the composite component is 98-60:2-40.

The porous powder material used in the invention has an acoustic enhancement function, and can be used for preparing the acoustic enhancement function material commonly used in the field. As a specific embodiment of the above-described acoustic reinforcement material of the present invention, wherein the porous powder material includes one or a combination of several of zeolite molecular sieve, active silica, active carbon, surface porous calcium carbonate, surface porous calcium silicate, alumina, hydrogel, aerogel, and the like.

As a specific embodiment of the above-mentioned acoustic enhancement material of the present invention, the zeolite molecular sieve has a particle size of 0.5-10 μm and comprises micropores with a pore diameter of 0.3-0.7nm and mesopores with a pore diameter of 10-30 nm.

In order to improve the acoustic enhancement effect of the acoustic enhancement material to a greater extent, as a specific embodiment of the acoustic enhancement material of the present invention, the zeolite molecular sieve includes one or a combination of several of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve, MTT structure molecular sieve, and the like.

As a specific embodiment of the above acoustic enhancement material of the present invention, the precipitation aid includes one or a combination of several of polyacrylamide, starch, polyethylenimine, polyimide, guar gum, and the like.

As a specific embodiment of the above-described acoustic enhancement material of the present invention, wherein the grammage of the acoustic enhancement material is in the range of 50 to 1200g/m ² 。

As a specific embodiment of the above-described acoustic enhancement material of the present invention, the shape of the acoustic enhancement material includes a sheet shape, a block shape, an irregular shape, or the like. In applying the acoustic enhancement material, one skilled in the art can reasonably select an appropriate shape of acoustic enhancement material as desired. In addition, the person skilled in the art can also combine the conventional means to obtain the acoustic enhancement material of the target shape on the basis of the manufacturing method provided by the invention.

In another aspect, the present invention further provides a method for manufacturing the acoustic enhancement material, where the manufacturing method includes:

step one: respectively dispersing fibrous materials, porous powder materials and precipitation aids in water to obtain fibrous material dispersion liquid, porous powder material dispersion liquid and precipitation aid dispersion liquid;

step two: adding the porous powder material dispersion liquid into the fibrous material dispersion liquid, uniformly mixing, adding the precipitation aid dispersion liquid, uniformly mixing, so that the fibrous materials are mutually interwoven, and simultaneously precipitating the porous powder material on the surface of the fibrous materials;

Step three: filtering the mixed solution obtained in the step two to obtain a precursor material;

step four: and drying the precursor material to obtain the acoustic enhancement material.

As a specific embodiment of the above manufacturing method of the present invention, when the fibrous material includes chemical fibers of a composite component, the manufacturing method further includes:

step five: and (3) carrying out high-temperature treatment on the acoustic reinforcing material under the condition that the temperature is not lower than the melting point of the cortex contained in the chemical fiber of the composite component, so that the cortex in the chemical fiber of the composite component is melted but the core layer is not melted, the cortex plays a role in bonding after being melted, and the acoustic reinforcing material with high strength and high efficiency can be obtained after cooling to room temperature after heat preservation.

In the present invention, the temperature of the high temperature treatment is selected according to the melting point of the skin layer. In some embodiments of the invention, the high temperature treatment may be carried out in a forced air drying oven, which may be at a temperature of 110-145 ℃, preferably 130-145 ℃, for a holding time of 5-20min.

The invention prepares the acoustic enhancement material by an integral molding method, wherein the integral molding refers to the process of forming a three-dimensional network structure by interweaving fibrous materials with porous powder materials attached to the surface in the process of molding the acoustic enhancement material, and the process can also be called coforming.

In a specific embodiment of the above manufacturing method according to the present invention, in the first step, the absolute dry mass concentration of the fibrous material in the fibrous material dispersion is 0.2 to 4% based on 100% of the total weight of the fibrous material dispersion.

In the first step, the absolute dry mass concentration of the porous powder material in the porous powder material dispersion is 1-50% based on 100% of the total weight of the porous powder material dispersion.

In the first step, the absolute dry mass concentration of the precipitation aid in the precipitation aid dispersion is 0.01-4.00% based on 100% of the total weight of the precipitation aid dispersion.

In one embodiment of the above manufacturing method of the present invention, in the first step, the water includes one or more of deionized water, distilled water and reverse osmosis water.

In the second step, which is a specific embodiment of the above-mentioned manufacturing method of the present invention, in order to achieve faster and better mixing uniformity, the step is performed under stirring. In the second step, the interweaving of the fibrous materials and the precipitation of the porous powder materials on the surface of the fibrous materials are performed simultaneously.

In the third step, the mixed solution obtained in the second step is filtered to primarily remove the water in the mixed solution, and the water content of the obtained material can be 10-80wt%. In the filtering process, water is directly filtered through a filter screen, fibrous materials with porous powder materials deposited on the surface are gradually piled up, and the fibrous materials are mutually staggered to construct a three-dimensional network structure.

The filtering in the third step is conventional operation and can be adjusted according to the actual operation condition of the site. For example, in some embodiments of the invention, the filtration is suction filtration.

The present invention can control the shape of the resulting acoustic enhancement material by the filtering operation in step three. If the filtering is carried out for a plurality of times in the third step, the thickness of the material stack is increased to form a blocky acoustic enhancement material, namely the thickness of the acoustic enhancement material can be controlled by the filtering; in addition, the acoustic enhancement materials with irregular shapes can be obtained by filtering with moulds with different shapes according to the requirement, and the acoustic enhancement materials with irregular shapes can be obtained by cutting the dried block-shaped or irregular-shaped acoustic enhancement materials.

In the fourth step, the drying is a conventional operation, and can be adjusted according to the actual operation condition in the field, so long as the removal of the moisture in the precursor material is ensured. For example, in some embodiments of the invention, the drying is performed by drying the precursor material using a vacuum freeze dryer or a forced air drying oven or the like.

In yet another aspect, the present invention also provides a speaker comprising one or more acoustic sensors, one or more housings, the one or more acoustic sensors in combination with the one or more housings forming a speaker rear cavity, wherein the speaker rear cavity is fitted with an acoustic enhancement material as described above.

In yet another aspect, the present invention also provides an electronic device, wherein the speaker rear cavity of the electronic device is fitted with the above-described acoustic enhancement material.

As a specific embodiment of the electronic device according to the present invention, the electronic device includes a smart phone, a TWS headset, a pair of smart glasses, a smart watch, a VR device, an AR device, a tablet computer, a light notebook computer, or the like.

Compared with the prior art, the invention has the following beneficial technical effects:

1. high-efficiency mass production: the invention can produce and prepare the acoustic enhancement material in high efficiency and mass without using special equipment and special raw materials and chemicals.

2. And (3) any cutting: the acoustic enhancement material provided by the invention can be cut into a required shape according to the size and the dimension of the rear cavity of the loudspeaker and filled in the rear cavity of the loudspeaker.

3. The acoustic performance is high-efficiency: the acoustic enhancement material provided by the invention has high-efficiency acoustic performance, and the acoustic performance of the porous powder material with the acoustic enhancement function per unit mass is superior to that of the acoustic enhancement particles commonly used in the market.

4. The strength is high: the acoustic enhancement material provided by the invention has higher strength, through drop test, the surface of the acoustic enhancement material is not subjected to powder falling, and the acoustic enhancement material is firm with double-sided adhesive tape, and the phenomenon of internal separation of the acoustic enhancement material is avoided, which is an important condition for ensuring long-term stable operation of the acoustic enhancement material in a cavity of a loudspeaker.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for the description of the embodiments will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of the morphology of the hydroxyl group-containing softwood fibers used in example 2 of the present invention.

Fig. 2 is a schematic view of the morphology of the softwood fiber used in example 4 of the present invention.

FIG. 3 is a schematic representation of the morphology of hardwood fibers used in example 4 of the present invention.

FIG. 4 is a schematic view of the morphology of the softwood fiber used in example 5 of the present invention.

FIG. 5 is a schematic representation of the morphology of hardwood fibers used in example 5 of the present invention.

Fig. 6 is a schematic form of the softwood fiber used in comparative example 2.

Fig. 7 is a schematic view of the morphology of the softwood fiber used in comparative example 5.

Fig. 8 is a schematic form of the hardwood fibers used in comparative example 5.

Fig. 9 is an SEM image of a sheet-like acoustic enhancement material provided in example 2 of the present invention.

Fig. 10 shows the surface morphology of the sheet-like acoustic enhancement material according to example 5 of the present invention after drop test in example 3 of the present invention.

FIG. 11 shows the surface morphology of the sheet-like acoustic enhancement material provided in comparative example 5 after drop testing in test example 3 according to the present invention.

Detailed Description

It should be noted that the term "comprising" in the description of the invention and the claims and any variations thereof in the above-described figures is intended to cover a non-exclusive inclusion, such as a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements that are expressly listed or inherent to such process, method, article, or apparatus.

The "range" disclosed herein is given in the form of a lower limit and an upper limit. There may be one or more lower limits and one or more upper limits, respectively. The 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 ranges. All ranges defined in this way are combinable, i.e. any lower limit can be combined with any upper limit to form a range. For example, ranges of 60-120 and 80-110 are listed for specific parameters, with the understanding that ranges of 60-110 and 80-120 are also contemplated. Furthermore, if the minimum range values listed are 1 and 2 and the maximum range values listed are 3,4 and 5, then the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

In the present invention, unless otherwise indicated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed throughout this disclosure, and "0-5" is only a shorthand representation of a combination of these values.

In the present invention, all the embodiments and preferred embodiments mentioned in the present invention may be combined with each other to form new technical solutions, unless otherwise specified.

In the present invention, all technical features mentioned in the present invention and preferred features may be combined with each other to form a new technical solution unless specifically stated otherwise.

In the present invention, all the steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially, unless otherwise specified. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, or may comprise steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), may include steps (a), (c) and (b), may include steps (c), (a) and (b), and the like.

The present invention will be further described in detail with reference to the accompanying drawings, figures and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. The following described embodiments are some, but not all, examples of the present invention and are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.

In the examples, the "moisture absorption ratio" of the plant fiber was measured as follows:

moisture absorption ratio= (Z/Y) ×100% formula 1.

In an embodiment, the absolute dry mass ratio of the porous powder material in the sheet acoustic reinforcement material can be measured by the following method:

Drying the sheet acoustic reinforcing material in a 110 ℃ oven to constant weight, and accurately weighing the mass of the sheet acoustic reinforcing material, and marking the mass as A;

accurately weighing the mass of a dried crucible, namely B, putting a sheet-shaped acoustic reinforcing material with the mass of A into the dried crucible, putting the crucible into a high-temperature muffle furnace, setting a heating program to be 0.5 ℃/min, heating to 525 ℃ from room temperature, preserving heat for 120min, and cooling to room temperature;

weighing the total weight of the crucible and the porous powder material with the acoustic enhancement function in the crucible, and recording as C;

after the sheet-shaped acoustic enhancement material with the mass A is burnt at high temperature, the mass of the porous powder material with the acoustic enhancement function is recorded as D, and D=C-B;

in the sheet-shaped acoustic reinforcing material having the mass a, the mass percentage of the porous powder material having the acoustic reinforcing function is denoted as E, and e= (D/a) ×100% formula 2.

The strength of the sheet acoustic reinforcement material is one of important indexes for evaluating the sheet acoustic reinforcement material, and is also an important guarantee for the application stability of the sheet acoustic reinforcement material. In the test example of the present invention, the strength of the sheet-like acoustic reinforcement material was measured as follows:

cutting a sheet acoustic enhancement material into a certain size (for example, a square with the size of 10 mm) and adhering the sheet acoustic enhancement material to the inner wall of a metal test tool through double faced adhesive tape, wherein the metal test tool is cuboid and has the mass of 220g;

The height of the automatic drop test machine is adjusted to be 180cm, the ground is marble, and the metal test tool adhered with the sheet-shaped acoustic enhancement material automatically drops on the marble ground through the height of 180 cm.

The 6 surfaces of the metal test fixture are subjected to drop tests, for example, each surface is subjected to drop tests for 6 times, and then the total drop tests are performed for 36 times. In some special cases, 12 drop tests per face are required, and a total of 72 drop tests are required.

After the drop test, the surface of the sheet-like acoustic enhancement material was observed for the presence (1): phenomenon of shedding of porous powder material having an acoustic enhancement function (2): whether or not the sheet-like acoustic reinforcement material is detached from the inside occurs.

The method comprises the following steps of (1) evaluating the bonding strength between a porous powder material and a three-dimensional network structure in the sheet-shaped acoustic enhancement material, and if no phenomenon of falling of the porous powder material is observed after drop test, indicating that the bonding strength between the porous powder material and the three-dimensional network structure in the sheet-shaped acoustic enhancement material is high.

(2) For evaluating the internal bond strength of the sheet acoustic reinforcement material. Since the sheet-like acoustic reinforcement material has a certain thickness and a certain mass, after drop test, a phenomenon in which separation occurs due to insufficient internal bonding strength may occur. After drop test, if no separation and falling-off of the interior of the sheet-like acoustic enhancement material are observed, the internal bonding strength is higher.

Example 1

The present example provides a sheet acoustic reinforcement material having a grammage of 800g/m ² The sheet acoustic enhancement material is formed by interweaving fibrous materials, wherein a three-dimensional network structure is arranged in the sheet acoustic enhancement material, and porous powder materials are attached to the surface of the fibrous materials through precipitation aids;

the fibrous material consists of plant fibers and chemical fibers of composite components, wherein the plant fibers are needle-leaved wood fibers containing hydroxyl groups, the average width of the needle-leaved wood fibers is 45 mu m, the length-diameter ratio of the needle-leaved wood fibers is 70, the absolute dry mass ratio of the needle-leaved wood fibers is 14.55%, and the moisture absorption ratio of the needle-leaved wood fibers is 29.5%;

the chemical fiber of the composite component is a chemical fiber of a composite component of a sheath-core structure (Ningbo chemical fiber Co., ltd., model VF-450 LM) and comprises a core layer and a skin layer for coating the core layer, wherein the core layer is a common polyester fiber (the melting point is 250-265 ℃), the skin layer is a modified polyester fiber (the melting point is 110 ℃), the diameter of the chemical fiber of the composite component is 50 mu m, the chemical fiber is cut down to have an length-diameter ratio of 40, and the absolute dry mass ratio is 5.0%;

the precipitation aid is starch with an average relative molecular weight of 55 ten thousand;

the porous powder material is ZSM-5 molecular sieve with an average particle diameter of 1.5 mu m and comprises micropores with a pore diameter of 0.55nm and mesopores with a pore diameter of 20 nm;

Based on the total weight of the sheet-shaped acoustic enhancement material as 100%, the absolute dry mass ratio of the fibrous material is 19.55%, the absolute dry mass ratio of the porous powder material is 80.0%, and the absolute dry mass ratio of the precipitation aid is 0.45%;

in this embodiment, the sheet acoustic reinforcement material is manufactured by a manufacturing method including the following specific steps:

step one: respectively dispersing fibrous materials, porous powder materials and precipitation aids in water according to the formula to obtain fibrous material dispersion liquid, porous powder material dispersion liquid and precipitation aid dispersion liquid;

wherein, in the fibrous material dispersion liquid, the absolute dry mass concentration of the fibrous material is 2.0 percent, in the porous powder material dispersion liquid, the absolute dry mass concentration of the porous powder material is 20 percent, in the precipitation auxiliary agent dispersion liquid, the absolute dry mass concentration of the precipitation auxiliary agent is 0.02 percent;

step two: adding the porous powder material dispersion liquid into the fibrous material dispersion liquid under the condition of stirring, uniformly mixing, adding the precipitation aid dispersion liquid, uniformly mixing, so that the fibrous materials are mutually interweaved, and simultaneously precipitating the porous powder material on the surface of the fibrous materials;

Step three: filtering the mixed solution obtained in the step two to obtain a sheet material, wherein the water content of the sheet material is 70wt%;

step four: carrying out forced air drying on the sheet material, wherein the forced air drying temperature is 110 ℃, the drying time is 120min, and the sheet acoustic reinforcing material is obtained after the drying is finished;

step five: placing the sheet-shaped acoustic enhancement material into a blast drying oven, keeping the temperature in the blast drying oven at 140 ℃, and preserving heat for 8min to perform high-temperature treatment on the sheet-shaped acoustic enhancement material so as to enable the cortex in the chemical fiber of the composite component to be molten and the core layer not to be molten, wherein the cortex plays a role in bonding after being molten, and after the heat preservation is finished, cooling the sheet-shaped acoustic enhancement material to room temperature to obtain the high-strength and high-efficiency sheet-shaped acoustic enhancement material; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-shaped acoustic enhancement material is measured by adopting the method, and is compared with the dosage of the porous powder material in the formula, and the comparison result shows that the absolute dry mass ratio and the dosage of the porous powder material are consistent.

Example 2

The fibrous material consists of plant fibers and chemical fibers of composite components, wherein the plant fibers are needle-leaved wood fibers containing hydroxyl groups, the average width of the needle-leaved wood fibers is 36 mu m, the length-diameter ratio of the needle-leaved wood fibers is 70, the absolute dry mass ratio of the needle-leaved wood fibers is 29.60%, and the moisture absorption ratio of the needle-leaved wood fibers is 22.5%; the morphology of the hydroxyl group-containing needle-leaved wood fiber is shown in fig. 1, and as can be seen from fig. 1, the surface of the hydroxyl group-containing needle-leaved wood fiber used in the present embodiment has a large amount of fine fibers;

the chemical fiber of the composite component is a chemical fiber of a composite component of a sheath-core structure (Ningbo chemical fiber Co., ltd., model VF-450 LM) and comprises a core layer and a skin layer for coating the core layer, wherein the core layer is a common polyester fiber (the melting point is 250-265 ℃), the skin layer is a modified polyester fiber (the melting point is 110 ℃), the diameter of the chemical fiber of the composite component is 50 mu m, the chemical fiber is cut down to have an length-diameter ratio of 40, and the absolute dry mass ratio is 10.0%;

the precipitation aid is polyacrylamide with molecular weight of 1500 ten thousand;

Based on the total weight of the sheet-shaped acoustic enhancement material as 100%, the absolute dry mass of the fibrous material is 39.60%, the absolute dry mass of the porous powder material is 60.0%, and the absolute dry mass of the precipitation aid is 0.40%;

Example 3

The fibrous material consists of an organic fibrous material and an inorganic fibrous material, wherein the organic fibrous material consists of plant fibers and chemical fibers of composite components, the plant fibers are needle-leaved wood fibers containing hydroxyl groups, the average width of the needle-leaved wood fibers is 45 mu m, the length-diameter ratio of the needle-leaved wood fibers is 70, the absolute dry mass ratio of the needle-leaved wood fibers is 40%, and the moisture absorption ratio of the needle-leaved wood fibers is 22.5%;

the chemical fiber of the composite component is a chemical fiber of the composite component with a parallel structure and comprises a high-melting-point fiber and a low-melting-point fiber, wherein the high-melting-point fiber is a common polyester fiber (the melting point is 250-265 ℃), the low-melting-point fiber is a polyethylene fiber (the melting point is 120 ℃), the diameter of the chemical fiber of the composite component is 50 mu m, the chemical fiber is cut down to have an slenderness ratio of 40, and the absolute dry mass ratio is 18.0%;

the inorganic fibrous material is glass fiber with an average diameter of 11 mu m and an slenderness ratio of 280, and the absolute dry mass ratio of the inorganic fibrous material is 1.65%;

the precipitation aid is guar gum with an average relative molecular weight of 160 ten thousand;

the total weight of the flaky acoustic reinforcing material is 100%, the absolute dry mass ratio of the fibrous material is 59.65%, the absolute dry mass ratio of the porous powder material is 40.0%, and the absolute dry mass ratio of the precipitation aid is 0.35%;

Example 4

The present embodiment provides a sheetAcoustic reinforcement material in the form of a sheet having a grammage of 800g/m ² The sheet acoustic enhancement material is formed by interweaving fibrous materials, wherein a three-dimensional network structure is arranged in the sheet acoustic enhancement material, and porous powder materials are attached to the surface of the fibrous materials through precipitation aids;

the fibrous material consists of 100% of organic fibrous material, wherein the absolute dry mass ratio of the hydroxyl group-containing needle-leaved wood fibers with the average width of 45 mu m and the length-diameter ratio of 70 is 21.55%, the moisture absorption ratio is 29.5%, the absolute dry mass ratio of the hydroxyl group-containing broad-leaved wood fibers with the average width of 17 mu m and the length-diameter ratio of 65 is 8.0%, and the moisture absorption ratio is 27.5%; the morphology of the needle-leaved wood fiber and the broad-leaved wood fiber is shown in fig. 2 and 3, and as can be seen from fig. 2 and 3, the surface of the plant fiber used in the embodiment has a large amount of fine fiber;

based on the total weight of the sheet-shaped acoustic enhancement material as 100%, the absolute dry mass ratio of the fibrous material is 29.55%, the absolute dry mass ratio of the porous powder material is 70.0%, and the absolute dry mass ratio of the precipitation aid is 0.45%;

step four: carrying out forced air drying on the sheet material, wherein the forced air drying temperature is 110 ℃, the drying time is 120min, and the sheet acoustic reinforcing material is obtained after the drying is finished; the absolute dry mass ratio of the porous powder material in the high-strength and high-efficiency sheet-shaped acoustic enhancement material is measured by adopting the method, and is compared with the dosage of the porous powder material in the formula, and the comparison result shows that the absolute dry mass ratio and the dosage of the porous powder material are consistent.

Example 5

the fibrous material consists of 100% of organic fibrous material, wherein the absolute dry mass ratio of the hydroxyl group-containing needle-leaved wood fibers with the average width of 45 mu m and the length-diameter ratio of 70 is 29.60%, the moisture absorption ratio is 22.5%, the absolute dry mass ratio of the hydroxyl group-containing broad-leaved wood fibers with the average width of 17 mu m and the length-diameter ratio of 65 is 10%, and the moisture absorption ratio is 25.5%; the morphology of the needle-leaved wood fiber and the broad-leaved wood fiber is shown in fig. 4 and 5, respectively, and as can be seen from fig. 4 and 5, the surface of the plant fiber used in the embodiment has a large amount of fine fiber;

Example 6

the fibrous material consists of an organic fibrous material and an inorganic fibrous material, wherein the absolute dry mass ratio of the hydroxyl group-containing needle wood fiber with the average width of 45 mu m and the length-diameter ratio of 70 is 30%, the moisture absorption ratio is 22.5%, the absolute dry mass ratio of the hydroxyl group-containing broad wood fiber with the average width of 17 mu m and the length-diameter ratio of 65 is 18%, the absolute dry mass ratio of the glass fiber with the moisture absorption ratio of 17.5% and the average diameter of 11 mu m and the length-diameter ratio of 280 is 1.65%;

based on the total weight of the sheet-shaped acoustic enhancement material as 100%, the absolute dry mass ratio of the fibrous material is 49.65%, the absolute dry mass ratio of the porous powder material is 50.0%, and the absolute dry mass ratio of the precipitation aid is 0.35%;

Example 7

the fibrous material consists of inorganic fibrous material and chemical fibers of composite components, wherein the inorganic fibrous material is glass fiber with an average diameter of 11 mu m and an aspect ratio of 280, and the absolute dry mass ratio of the inorganic fibrous material is 14.55%;

Comparative example 1

This comparative example provides an acoustic enhancement particle which is a commercially available conventional product having an average particle size of 420 μm.

Comparative example 2

This comparative example provides a sheet-like acoustic reinforcement material which differs from example 2 in that:

the moisture absorption ratio of the needle wood fiber was 14.0%, and a general polyester fiber was used instead of the chemical fiber of the composite component. As shown in fig. 6, the morphology of the softwood fibers was the same as that of the softwood fibers used in the comparative example, and as can be seen from fig. 6, the surface fine fibers of the softwood fibers having a moisture absorption ratio of 14.0% were very small.

Comparative example 3

the moisture absorption ratio of the needle wood fiber is 14.0%.

Comparative example 4

common polyester fibers are used instead of chemical fibers of composite components.

Comparative example 5

This comparative example provides a sheet-like acoustic reinforcement material which differs from example 5 only in that:

the moisture absorption ratio of the needle-leaved wood fiber is 14.0%, and the moisture absorption ratio of the broadleaf wood fiber is 15.0%. Among them, the morphology of the needle-leaved wood fiber and the broad-leaved wood fiber is shown in fig. 7 and 8, respectively, and it can be seen from fig. 7 and 8 that the plant fiber used in the present comparative example has few surface fibrils.

Comparative example 6

the moisture absorption ratio of the needle-leaved wood fiber is 32.0%, and the moisture absorption ratio of the broadleaf wood fiber is 33.0%.

Test example 1

The sheet-like acoustic reinforcement material provided in example 2 of the present invention was subjected to SEM analysis, and the SEM image obtained is shown in fig. 9. As can be seen from fig. 9, the sheet-like acoustic reinforcement material provided in embodiment 2 of the present invention has a large number of pore structures, i.e., three-dimensional network structures formed by interweaving fibrous materials, and has high porosity. From this, it can be reasonably presumed that a great deal of pore structures exist in the sheet-shaped acoustic reinforcing material prepared by other embodiments of the present invention, and the porosity is high.

Test example 2

This test example the sheet-like acoustic reinforcement materials provided in examples 1 to 7 and comparative examples 2 to 6 above were cut into 10 x 10mm sizes, weighed, and then the resonance frequency shift value Δf0 of the sheet-like acoustic reinforcement materials was measured according to the 7.4 part of the group standard porous sound absorbing particles for micro speakers (standard number: T/CECA 78-2022), respectively, and the specific results are shown in table 1 below.

Table 1 acoustic performance data for the sheet-like acoustic enhancement materials of example 1-example 7 and comparative example 2-comparative example 6

The sheet-like acoustic reinforcements obtained in examples 1 to 7 and comparative examples 2 to 6 were cut into a size of 10 x 10mm by calculation, and the molecular sieve oven dry mass in each sheet-like acoustic reinforcement was: 64.0mg, 48.0mg, 32.0mg, 56.0mg, 48.0mg, 40.0mg, 64.0mg, 48.0mg and 48.0mg.

The acoustic efficiency per unit mass of the sheet-like acoustic enhancement material was then calculated according to the formula shown below, and the resulting acoustic efficiency data are shown in table 2 below.

Acoustic efficiency = Δf0/(absolute dry mass of molecular sieve), units: hz/mg.

Table 2 acoustic efficiency data for the sheet-like acoustic enhancement materials of example 1-example 7 and comparative example 2-comparative example 6

From the experimental data in tables 1 and 2 above, it is understood that the sheet-like acoustic reinforcing materials provided in examples 1 to 7 of the present invention all have high-efficiency acoustic properties.

The present test example also accurately weighed 64.0mg, 56.0mg, 48.0mg, 40.0mg and 32.0mg of the acoustic enhancement particles provided in comparative example 1, and tested the resonance frequency shift value Δf0 of the acoustic enhancement particles according to the 7.4 part of the group standard porous sound absorbing particles for micro speakers (standard number: T/CECA 78-2022), respectively, and the specific results are shown in Table 3 below.

TABLE 3 Acoustic performance and acoustic efficiency data for commercially available conventional acoustically enhanced particles

Comparing the experimental data in tables 1-2 and 3, it can be seen that the acoustic properties of the sheet-like acoustic enhancement materials provided in examples 1-7 of the present invention are significantly better than those of conventional acoustic enhancement particles on the market.

The experimental data in tables 1-2 and 3 are compared to one another to obtain: comparative example 2, comparative example 3, comparative example 4 provide the same acoustic performance of the sheet-like acoustic enhancement material as compared to inventive example 2. This is mainly because: whether the chemical fibers of the composite component or the ordinary polyester fibers, their addition has substantially no effect on the acoustical properties of the sheet-like acoustical enhancement material. The main difference between the sheet-like acoustic reinforcing materials provided in these examples and comparative examples is that the sheet-like acoustic reinforcing material provided in example 2 of the present invention has a high internal bond strength; whereas comparative examples 2, 3 and 4 provide sheet-like acoustic reinforcements with far lower internal bond strengths than example 2, see Table 4 and the associated description of Table 4.

The absolute dry mass ratio of the molecular sieves of the sheet acoustic reinforcement materials provided in example 2 and example 5 of the present invention was the same, and was 60.0%. But example 2 provided a sheet acoustic enhancement material with slightly better acoustic properties than example 5 because: in example 2, a chemical fiber of a sheath-core structure composite component having an absolute dry mass ratio of 10.0% was added.

For the sheet acoustic reinforcement materials provided in examples 1 and 7 of the present invention, the molecular sieves were all 80% dry weight. But the acoustic properties of the sheet acoustic enhancement material provided in example 1 are slightly better than those of example 7 because: needle wood fibers with an absolute dry mass ratio of 14.55% were added in example 1, while glass fibers with an absolute dry mass ratio of 14.55% were added in example 7. It is known that the glass fibers have a density much higher than that of the needle wood fibers, and thus the sheet-like acoustic reinforcement material obtained in example 7 has a density also higher than that obtained in example 1, and accordingly has acoustic properties slightly lower than those of the sheet-like acoustic reinforcement material provided in example 1.

The absolute dry mass ratio of the molecular sieves of the sheet acoustic reinforcement materials provided in example 5 and comparative example 5 of the present invention was the same, and was 60%. Although the moisture absorption ratio of the needle-leaved wood fiber used in comparative example 5 was only 14.0% and the moisture absorption ratio of the broad-leaved wood fiber was only 15.0%, the acoustic properties of the sheet-like acoustic reinforcing material provided in comparative example 5 and the sheet-like acoustic reinforcing material provided in example 5 were substantially the same. This is because: when the fibrous material is smaller in moisture absorption, the specific surface area is also smaller, which mainly restricts the binding of the porous powder material to the fibrous material, thereby decreasing the strength of the sheet-like acoustic reinforcement material (as shown in experimental data in test example 3 below), while having less influence on the acoustic properties of the sheet-like acoustic reinforcement material.

The absolute dry mass ratio of molecular sieves was 60% for the sheet acoustic reinforcement provided in inventive example 5 and comparative example 6, respectively. However, since the moisture absorption ratio of the needle-leaved wood fiber used in comparative example 6 was 32.0% and the moisture absorption ratio of the broad-leaved wood fiber was 33.0%, the area of the inter-bonding between the fibrous materials used in comparative example 6 was too large, resulting in insufficient voids of the sheet-like acoustic reinforcement material, making its acoustic properties far inferior to that of the sheet-like acoustic reinforcement material provided in example 5.

Test example 3

The test example firstly cuts the sheet acoustic enhancement materials provided in the embodiment 2 and the comparative embodiment 2 and the embodiment 5 and the comparative embodiment 5 into squares of 10 x 10mm, then respectively adheres the squares to the inner wall of a metal test tool with the mass of 220g through double faced adhesive tape, then adjusts the height of an automatic drop test machine to 180cm, and the ground is marble, and automatically drops the metal test tool adhered with the sheet acoustic enhancement materials on the marble ground through the height of 180 cm. Wherein, the 6 faces of the metal test fixture are all subjected to drop test for 6 times and are subjected to drop test for 36 times.

After 36 drop tests, the sheet-like acoustic reinforcing materials provided in examples 2 and 5 of the present invention were still completely adhered to the inner wall of the test fixture. Fig. 10 is an image of the sheet-like acoustic enhancement material provided in example 5 of the present invention after falling (image after delamination tearing), showing the sheet-like acoustic enhancement material intact without separation.

After 36 drop tests, the sheet-shaped acoustic enhancement materials provided in comparative examples 2 and 5 were separated internally, and a part of the sheet-shaped acoustic enhancement materials were adhered to the inner wall of the test fixture to expose the fibrous material and the porous powder material inside. FIG. 11 is an image of the sheet-form acoustic enhancement material provided in comparative example 5 after delamination, showing separation of the interior of the sheet-form acoustic enhancement material, indicating insufficient bonding strength within the sheet-form acoustic enhancement material.

Comparing the drop test results of the sheet acoustic enhancement materials provided in the examples 2 and 5 of the present invention, it is known that the strength of the sheet acoustic enhancement material can be significantly improved by controlling the moisture absorption ratio of the organic fibrous material in the sheet acoustic enhancement material to be within a specific numerical range of 16.0-31.5% and using the chemical fibers of the composite component, and the long-term stable operation of the sheet acoustic enhancement material in the speaker cavity can be ensured.

Test example 4

The test example firstly cuts the sheet acoustic enhancement materials provided in the example 2 and the comparative examples 2-4 into squares of 10 x 10mm, then respectively adheres the squares to the inner wall of a metal test tool with the mass of 220g through double faced adhesive tape, and then adjusts the height of an automatic drop test machine to 180cm, wherein the ground is marble. The metal test tool adhered with the sheet-shaped acoustic enhancement material is automatically dropped on the marble floor through the height of 180 cm. Wherein, 6 faces of the metal test fixture are all dropped for the same times until all the sheet acoustic enhancement materials are separated. The total number of drops in which the sheet-like acoustic enhancement materials provided in example 2, comparative example 2-comparative example 4 were separated is shown in table 4 below.

Table 4 total number of drops in which the sheet acoustic reinforcement material of example 2, comparative example 2-comparative example 4 separated

	Total number of falls
		Example 2	120
Comparative example 2	6
		Comparative example 3	48
Comparative example 4	72

As can be seen from table 4, with the sheet-like acoustic reinforcement material provided in example 2, the complete separation did not occur until the total number of falls was 120. The moisture absorption ratio of the needle-leaved wood fibers used in comparative example 3 was not acceptable, and the common polyester fibers, instead of the chemical fibers of the composite components, were used in comparative example 4, but the total number of drops corresponding to the complete separation of the sheet-like acoustic reinforcement materials provided in comparative example 3 and comparative example 4 was also relatively high, but significantly lower than that of example 2. For comparative example 2, in which the moisture absorption ratio of the needle wood fiber used was not acceptable and a common polyester fiber was used instead of the chemical fiber of the composite component, the sheet-like acoustic reinforcement material provided in comparative example 2 was subjected to the total number of drops corresponding to the occurrence of the complete separation phenomenon of only 6 times, which is significantly lower than that of comparative examples 3 to 4 and example 2.

The experimental results also show that the strength of the sheet-shaped acoustic enhancement material can be obviously improved by controlling the moisture absorption ratio of the organic fibrous material in the sheet-shaped acoustic enhancement material within a specific numerical range of 16.0-31.5% and using chemical fibers of composite components, so that the long-term stable operation of the sheet-shaped acoustic enhancement material in a loudspeaker cavity is ensured.

The foregoing description of the embodiments of the invention is not intended to limit the scope of the invention, so that the substitution of equivalent elements or equivalent variations and modifications within the scope of the invention shall fall within the scope of the patent. In addition, the technical features and the technical features, the technical features and the technical invention can be freely combined for use.

Claims

1. The acoustic enhancement material is characterized by being formed by interweaving fibrous materials, wherein the interior of the acoustic enhancement material is provided with a three-dimensional network structure, and the surface of the fibrous materials is adhered with a porous powder material through a precipitation auxiliary agent;

2. Acoustic reinforcement material according to claim 1, characterized in that the fibrous material has an absolute dry mass ratio of 19.50-85.95%, the porous powder material has an absolute dry mass ratio of 14.0-80.0%, preferably 50.0-70.0%, and the precipitation aid has an absolute dry mass ratio of 0.05-0.5% based on 100% of the total weight of the acoustic reinforcement material.

3. The acoustic reinforcement material of claim 1, wherein the fibrous material has a diameter or width in the range of 3-70 μm and an aspect ratio in the range of 8-500.

4. An acoustic reinforcement according to claim 3, wherein the inorganic fibers have a diameter or width in the range of 3-45 μm and an aspect ratio of 10-500.

5. The acoustical enhancement material of any of claims 1-4, wherein the inorganic fibers comprise one or a combination of basalt fibers, glass fibers, quartz fibers, asbestos fibers, volcanic fibers, metal fibers, alumina fibers, and carbon fibers.

6. An acoustic reinforcement material according to claim 3, wherein the plant fiber has a diameter or width in the range of 8-70 μm and an aspect ratio in the range of 8-150.

7. An acoustic reinforcement material according to any of claims 1-3,6, characterized in that the moisture absorption ratio of the plant fiber is 16.0-31.5%, preferably 20.0-31.5%.

8. The acoustic reinforcement material of claim 7, wherein the plant fiber is a fibrous material prepared from natural plants, wherein the natural plants comprise one or a combination of several of softwood, hardwood, hemp, bamboo, straw, bagasse, reed, and cotton.

9. An acoustic reinforcement according to claim 3, wherein the chemical fibers of the composite component have a diameter or width in the range of 10-70 μm and an aspect ratio in the range of 10-200.

10. The acoustic reinforcement material of any of claims 1-3,9, wherein the chemical fibers of the composite component comprise one or a combination of several of sheath-core structure, side-by-side structure, islands-in-the-sea structure composite component chemical fibers;

preferably, the chemical fibers of the side-by-side structural composite component include chemical fibers having a melting point of not higher than 140 ℃ and chemical fibers having a melting point of not lower than 150 ℃;

more preferably, the chemical fibers with a melting point not higher than 140 ℃ comprise polyethylene fibers and/or modified polyester fibers, and the chemical fibers with a melting point not lower than 150 ℃ comprise common polyester fibers and/or polypropylene fibers;

it is also preferable that the matrix of the chemical fibers of the island-in-the-sea composite component comprises chemical fibers having a melting point of not higher than 140 ℃, and the dispersed phase comprises chemical fibers having a melting point of not lower than 150 ℃;

still more preferably, the matrix material comprises polyethylene fibers and/or modified polyester fibers and the dispersed phase material comprises conventional polyester fibers and/or polypropylene fibers.

11. The acoustic reinforcement material according to claim 10, wherein the chemical fibers of the composite component of the sheath-core structure include a core layer and a sheath layer covering the core layer, and the material of the sheath layer includes chemical fibers having a melting point of not higher than 140 ℃, and the material of the core layer includes chemical fibers having a melting point of not lower than 150 ℃.

12. The acoustic reinforcement of claim 11, wherein the core layer comprises plain polyester fibers and/or polypropylene fibers and the skin layer comprises polyethylene fibers and/or modified polyester fibers.

13. An acoustic reinforcement according to any of claims 1-3, characterized in that the absolute dry mass ratio of vegetable fibres to chemical fibres of the composite component is 98-60:2-40.

14. The acoustic reinforcement material of claim 1, wherein the porous powder material comprises one or a combination of several of zeolite molecular sieve, activated silica, activated carbon, surface porous calcium carbonate, surface porous calcium silicate, alumina, hydrogel, aerogel.

15. The acoustic reinforcement material of claim 14, wherein the zeolite molecular sieve has a particle size of 0.5-10 μm and comprises micropores with a pore size of 0.3-0.7nm and mesopores with a pore size of 10-30 nm.

16. The acoustic reinforcement material of claim 14 or 15, wherein the zeolite molecular sieve comprises one or a combination of several of MFI structure molecular sieve, FER structure molecular sieve, CHA structure molecular sieve, MEL structure molecular sieve, TON structure molecular sieve, and MTT structure molecular sieve.

17. The acoustic enhancement material of claim 1, wherein the precipitation aid comprises one or a combination of several of polyacrylamide, starch, polyethylenimine, polyimide, and guar gum.

18. The acoustic reinforcement material of any of claims 1-4, wherein the acoustic reinforcement material has a grammage in the range of 50-1200g/m ² 。

19. The acoustic enhancement material of any of claims 1-4, wherein the shape of the acoustic enhancement material comprises a sheet, block, or irregular shape.

20. A method of making an acoustic enhancement material according to any one of claims 1 to 19, wherein said method of making comprises:

step four: drying the precursor material to obtain an acoustic enhancement material;

preferably, when the fibrous material comprises chemical fibers of a composite component, the method of making further comprises:

step five: the acoustic reinforcement material is subjected to a high temperature treatment under a condition that the temperature is not lower than the melting point of the skin layer contained in the chemical fiber of the composite component so that the skin layer in the chemical fiber of the composite component is melted and the core layer is not melted.

21. A loudspeaker comprising one or more acoustic sensors, one or more housings, the one or more acoustic sensors in combination with the one or more housings forming a loudspeaker back volume, wherein the loudspeaker back volume is fitted with an acoustic enhancement material as claimed in any one of claims 1 to 19.

22. An electronic device, characterized in that an acoustic enhancement material according to any of claims 1-19 is fitted in a speaker rear cavity of the electronic device.

23. The electronic device of claim 22, wherein the electronic device comprises a smart phone, a TWS headset, a smart glasses, a smart watch, a VR device, an AR device, a tablet, or a lightweight notebook.