Composite sound-absorbing material, preparation method and electronic equipment

Abstract

The invention relates to the technical field of acoustic materials, and particularly provides a composite sound-absorbing material, a preparation method and electronic equipment. The preparation method of the composite sound-absorbing material comprises the following steps: uniformly dispersing the structure reinforced fibers and the porous sound-absorbing material in an aerogel sol solution to obtain an aerogel composite sol solution, performing a gelation process on the aerogel composite sol solution to obtain composite wet gel, and drying the composite wet gel to obtain the composite sound-absorbing material. The composite sound-absorbing material, the preparation method and the electronic equipment provided by the embodiment of the invention are used for reducing the use of a binder and avoiding the problems of burr and chip falling during cutting.

Description

Technical Field

[0001] The present disclosure relates to the technical field of acoustic materials, and in particular to a composite sound-absorbing material, a preparation method thereof, and an electronic device. Background Art

[0002] With the continuous upgrading of electronic products such as mobile phones, laptops, augmented reality (AR), virtual reality (VR), etc., the size of electronic products is getting smaller and smaller, so the space for speakers is getting smaller and smaller. Due to space limitations, the resonance cavity of the speaker is getting smaller and smaller, resulting in an increase in the resonance frequency and a decrease in the low-frequency sound pressure sensitivity, making it difficult to improve its performance in the low-frequency range. At present, the low-frequency performance of micro speakers is mainly improved by filling the speaker cavity with sound-absorbing balls. However, when improving the low-frequency response by filling the sound-absorbing balls, the sound-absorbing balls will inevitably break due to vibration.

[0003] Therefore, in the related art, the sound-absorbing balls are bonded with adhesives and then cut to prepare sound-absorbing materials that match the size of the speaker cavity. However, on the one hand, the use of adhesives increases the cost and is not environmentally friendly. On the other hand, the cutting process is prone to burrs or chips. Summary of the invention

[0004] The present disclosure is proposed in view of the above problems. The present disclosure provides a composite sound-absorbing material and a preparation method thereof and an electronic device, which reduces the use of adhesives and avoids the problems of burrs and chips during cutting.

[0005] According to a first aspect of the present disclosure, there is provided a method for preparing a composite sound-absorbing material, comprising:

[0006] The structural reinforcement fiber and the porous sound absorbing material are uniformly dispersed in the aerogel sol liquid to obtain an aerogel composite sol liquid;

[0007] Performing a gelling process on the aerogel composite sol liquid to obtain a composite wet gel;

[0008] The composite wet gel is dried to obtain a composite sound-absorbing material.

[0009] According to a second aspect of the present disclosure, a composite sound-absorbing material is provided, including: the composite sound-absorbing material is a three-dimensional network structure, and the composite sound-absorbing material includes aerogel and structural reinforcement fibers and porous sound-absorbing materials uniformly dispersed in the aerogel.

[0010] According to a third aspect of the present disclosure, an electronic device is provided, comprising the composite sound absorbing material according to the second aspect of the present disclosure.

[0011] In one or more technical solutions provided in the embodiments of the present disclosure, first, the structural reinforcement fibers and the porous sound-absorbing material are uniformly dispersed in the aerogel sol liquid to obtain an aerogel composite sol liquid. When the porous sound-absorbing material is uniformly dispersed in the aerogel sol liquid, the porous structure of the aerogel and the porous structure of the sound-absorbing material cooperate with each other to form a more complex and multi-level sound-absorbing channel. At the same time, the addition of the structural reinforcement fibers can play the role of supporting the skeleton inside the aerogel sol liquid, which can significantly improve the strength and toughness of the aerogel. Then, the aerogel composite sol liquid is subjected to a gelation process to obtain a composite wet gel. During the gelation process, the structural reinforcement fibers, porous sound-absorbing materials and aerogel matrix originally dispersed in the aerogel sol liquid will gradually form a relatively stable and fixed three-dimensional network structure through a series of physical and chemical effects (such as intermolecular forces, chemical bonding, etc.). The relatively disordered pores of the aerogel are compounded with other materials and gelled, which optimizes the connectivity and pore size distribution of the pores, making the propagation of sound waves in the pores smoother and improving the sound absorption performance. Next, the composite wet gel is dried to obtain a composite sound-absorbing material. During the drying process, the pore structure inside the composite wet gel will be further adjusted and optimized, and the pores will become more transparent and regular. After the sound waves enter the material, they can be more smoothly propagated, reflected and fully absorbed in these regular and interconnected pores, so that the composite sound-absorbing material can achieve better sound absorption effect in a wider frequency range.

[0012] On this basis, the embodiments of the present disclosure do not require the use of a binder for particle molding, which can prevent the binder from clogging the pores of the porous sound-absorbing material, and can maximize the integrity of the porous sound-absorbing material's own pore structure, thereby maintaining good sound absorption capabilities.

[0013] In addition, in the composite sound-absorbing material of the embodiment of the present disclosure, the structural reinforcement fibers and the porous sound-absorbing material are combined, interwoven and filled with each other through the nanoparticles to form a relatively tight whole. The porous zeolite powder is embedded in the pores of the aerogel or attached to its surface. When cutting, this tight combination can reduce the zeolite powder from falling off the aerogel matrix, so it is not easy to produce burrs or chips. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above and other purposes, features and advantages of the present disclosure will become more apparent by describing the embodiments of the present disclosure in more detail in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0015] Figure 1 A flowchart of the preparation of the acoustic enhancement material block according to an embodiment of the present disclosure;

[0016] Figure 2 It is a schematic diagram of the cross-sectional structure of the acoustic enhancement material block according to an embodiment of the present disclosure.

[0017] 210- aerogel, 220- structural reinforcement fiber, 230- porous sound absorbing material. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present disclosure more obvious, the exemplary embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments of the present disclosure, and it should be understood that the present disclosure is not limited to the exemplary embodiments described here.

[0019] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0020] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, "multiple" means two or more, unless otherwise clearly and specifically defined. "Several" means one or more, unless otherwise clearly and specifically defined.

[0021] In the description of the present disclosure, it is necessary to understand that the directions or positional relationships indicated by the terms "upper", "lower", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present disclosure.

[0022] In the description of the present disclosure, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present disclosure can be understood according to specific circumstances.

[0023] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present disclosure should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0024] In the present invention, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0025] In traditional audio, porous sound-absorbing materials such as activated carbon, sound-absorbing cotton or fiber products are widely used to improve sound absorption performance. However, in consumer electronic micro speakers represented by mobile phones, laptops, AR and VR devices, the contradiction between acoustic performance and space in the low-frequency part has long existed due to volume limitations. Through practice, scientists have creatively proposed the "Virtual Back Volume" (VBV) technology, which successfully solved the problem of sound-absorbing products in smartphones, namely: using granular porous materials of special materials or different packaging forms of these materials, when the speaker diaphragm vibrates at high frequency, the high-frequency adsorption and desorption of air are achieved through a fine three-dimensional pore structure, thereby reducing the resistance of the diaphragm, forming an acoustic effect similar to increasing the actual physical back cavity, reducing the resonant frequency, and greatly increasing the acoustic performance, especially the low-frequency performance.

[0026] At present, sound-absorbing particles are usually filled into the speaker cavity by canning, but the canning process is relatively difficult. In particular, the resonance cavity space of some micro speakers is very small, and its spatial height is in the range of hundreds of microns. It is very difficult to quantitatively fill sound-absorbing particles in such a narrow resonance cavity. However, the narrow resonance cavity often has the greatest impact on low frequencies, and it is also the structure that most needs to be filled with sound-absorbing materials. Secondly, during the operation of the speaker, traditional sound-absorbing particles vibrate at high frequencies in the cavity and collide with the inner wall of the cavity, causing the sound-absorbing particles to break and break into powder, damaging the speaker unit. In addition, in the current filling process, sound-absorbing particles can only fill about 80% of the volume of the back cavity of the speaker module, and cannot fully utilize the back cavity space.

[0027] Therefore, in order to overcome the above problems, the related art uses adhesive to bond the sound-absorbing balls and then cuts them to prepare sound-absorbing materials that match the size of the speaker cavity. However, on the one hand, the use of adhesives increases the cost and is not environmentally friendly. On the other hand, the cutting process is prone to burrs or chips.

[0028] In view of the above problems, the embodiments of the present disclosure provide a composite sound-absorbing material, a preparation method and an electronic device, which reduce the use of adhesives, avoid the problem of burrs and chips during cutting, and ensure the stability of the composite sound-absorbing material during use. The electronic device may include at least one of a smart phone, a tablet computer, a laptop computer, a smart watch, VR and AR.

[0029] The embodiment of the present disclosure provides a method for preparing a composite sound-absorbing material, which can be used to prepare the composite sound-absorbing material of the embodiment of the present disclosure. Figure 1 The preparation process of the composite sound-absorbing material of the embodiment of the present disclosure is shown in FIG. Figure 1 As shown, the preparation method of the composite sound-absorbing material of the embodiment of the present disclosure includes:

[0030] Step 101: uniformly dispersing the structural reinforcement fibers and the porous sound-absorbing material in the aerogel sol solution to obtain an aerogel composite sol solution.

[0031] For the above-mentioned structural reinforcement fibers, they can be high-strength, high-modulus fibers, which can include at least one of organic fibers and inorganic fibers. For example, the structural reinforcement fibers can include at least one of carbon fibers, aramid fibers, ultra-high molecular weight polyethylene fibers or basalt fibers. The mechanical properties of the aerogel itself contained in the aerogel sol liquid are relatively weak, and it is easy to deform or even break when subjected to greater pressure. Therefore, high-strength, high-modulus fibers are uniformly dispersed in the aerogel sol liquid. When the aerogel composite sol liquid is solidified and formed, the fibers support the structure of the aerogel like a skeleton, thereby improving the tensile strength of the aerogel composite sol liquid.

[0032] Exemplarily, the length of the structural reinforcement fibers is selected from 1 mm to 3 mm. When the length of the structural reinforcement fibers is in the range of 1 mm to 3 mm, it is easier to achieve uniform dispersion in the aerogel sol liquid without causing mutual entanglement, and sufficient connection and support can be formed inside the material. At the same time, it can further optimize the propagation path of sound waves in the material without destroying the original sound absorption channel.

[0033] Exemplarily, the strength of the structural reinforcement fiber is ≥10CN / dkex, and the modulus of the structural reinforcement fiber is ≥200CN / dkex. The structural reinforcement fiber with a strength of ≥10CN / dkex and a modulus of ≥200CN / dkex can limit the deformation of the aerogel material and maintain the stability of the material structure through its own high strength and high modulus properties, thereby extending the service life of the material.

[0034] The porous sound absorbing material may include zeolite molecular sieves, which include at least one of MFI zeolite molecular sieves, ZSM-5 zeolite molecular sieves, X-type zeolite molecular sieves, FER zeolite molecular sieves, and MOR zeolite molecular sieves.

[0035] Exemplarily, the particle size of the zeolite molecular sieve is 20nm to 500nm. Zeolite molecular sieves in this particle size range can be well dispersed in the aerogel sol liquid. This avoids the problem of uneven dispersion caused by rapid sedimentation due to gravity when the particle size is too large, and also prevents the problem of agglomeration and difficulty in uniform dispersion caused by small particle size.

[0036] For the above-mentioned aerogel sol liquid, it can include at least one of SiO2 aerogel sol liquid, Al2O3 aerogel sol liquid, Fe2O3 aerogel sol liquid and NiO3 aerogel sol liquid. Aerogel has good chemical stability and can maintain structural stability under general acid and alkali environments. Therefore, the stability of the composite sound-absorbing material can be further improved. The preparation process of the aerosol gel liquid can adopt the sol-gel method or other existing processes, which are not limited here.

[0037] For example, the method for preparing the above-mentioned SiO2 aerogel sol liquid may include: mixing a silicon source (such as tetraethyl orthosilicate), a solvent (such as ethanol) and a catalyst (such as hydrochloric acid), and performing hydrolysis and polycondensation reactions under certain conditions to form SiO2 sol. Then, by adjusting the reaction conditions (such as temperature, pH value, concentration, etc.), the gelation process of the sol is controlled to obtain the SiO2 aerogel sol liquid.

[0038] In the embodiment of the present disclosure, when the porous sound-absorbing material is evenly dispersed in the aerogel sol liquid, the porous structure of the aerogel and the porous structure of the sound-absorbing material cooperate with each other to form a more complex and multi-layered sound-absorbing channel. At the same time, the addition of structural reinforcement fibers can play the role of supporting the skeleton inside the aerogel sol liquid, which can significantly improve the strength and toughness of the aerogel.

[0039] Step 102: performing a gelation process on the aerogel composite sol liquid to obtain a composite wet gel.

[0040] For example, the gel process can firstly disperse the aerogel composite sol solution by ultrasonic dispersion, and then undergo hydrolysis and polycondensation to form nanoclusters with different structures, and the clusters adhere to each other to form a composite wet gel. It should be understood that the gel process can adopt a conventional gel process, which is not limited here.

[0041] For example, after the aerogel composite sol liquid is ultrasonically dispersed, a solvent (such as ethanol) can be added to the aerogel composite sol liquid, and then the gelation process is carried out in an acidic catalytic system with a hydrochloric acid concentration of 0.01 mol / L to 0.1 mol / L, at a reaction temperature of 30°C to 80°C, and a stirring speed of 200rpm to 800rpm, until the viscosity of the solution suddenly increases and the fluidity is significantly reduced, that is, the gel point is reached, and a composite wet gel is obtained. Among them, the volume ratio of ethanol to precursor is between (3 to 8):1.

[0042] During the gelation process, a relatively stable and fixed three-dimensional network structure is gradually formed between the structural reinforcing fibers, porous sound-absorbing materials and aerogel matrix originally dispersed in the aerogel sol liquid through a series of physical and chemical reactions (such as intermolecular forces, chemical bonding, etc.). After the relatively disordered pores of the aerogel are compounded and gelated with other materials, the connectivity and pore size distribution of the pores are optimized, making the propagation of sound waves in the pores smoother and improving the sound absorption performance.

[0043] Step 103: Drying the composite wet gel to obtain a composite sound-absorbing material.

[0044] Exemplarily, the composite wet gel may be dried by supercritical drying process and / or normal pressure drying to obtain a composite sound-absorbing material. It should be understood that the supercritical drying process is a drying technology that heats the drying medium to a supercritical point, so that the capillary stress does not exist when the gel removes the solvent, avoids the collapse of the gel structure when the solvent is removed, and thus can maintain the original shape of the gel.

[0045] During the above-mentioned drying process, the pore structure inside the composite wet gel will be further adjusted and optimized, and the pores will become more transparent and regular. After the sound waves enter the material, they can propagate, reflect and be fully absorbed more smoothly in these regular and interconnected pores, thereby enabling the composite sound-absorbing material to achieve better sound absorption effects in a wider frequency range.

[0046] In one example, if the above-mentioned drying process adopts a supercritical drying process, the embodiment of the present disclosure dries the composite wet gel to obtain a composite sound-absorbing material block, specifically including: placing the composite wet gel in a pressure vessel and heating and pressurizing it so that the liquid in the composite wet gel undergoes a phase change and is converted into a supercritical fluid to obtain a composite sound-absorbing material.

[0047] The process conditions of the supercritical drying process include: the supercritical drying temperature is 35° C. to 40° C., the supercritical drying pressure is 4.5 MPa to 5.5 MPa, and the supercritical drying time is 15 h to 17 h.

[0048] If the above drying process adopts normal pressure drying, the normal pressure drying temperature is 40° C. to 80° C., and the normal pressure drying time is 2 h to 50 h.

[0049] In one achievable manner, in the composite sound-absorbing material of the embodiment of the present disclosure, the mass ratio of the porous sound-absorbing material, the structural reinforcement fiber and the aerogel sol liquid is (30-66): (4-15): (30-55). This mass ratio range helps to maintain the stability of the sound-absorbing material. The mass ratio of the porous sound-absorbing material and the aerogel sol liquid enables the material to maintain a stable pore structure after curing, and will not cause pore collapse or loose structure due to too much or too little of a certain component. At the same time, if the mass ratio of the structural reinforcement fiber is too high, it may affect the pore structure of the sound-absorbing material and thus reduce the sound absorption performance; and if the mass ratio is too low, the mechanical properties of the material cannot be effectively enhanced. This reasonable mass ratio enables the porous sound-absorbing material, the structural reinforcement fiber and the aerogel sol liquid to work synergistically to achieve a balance between sound absorption and mechanical properties.

[0050] In order to prevent the surface tension in the micropores during the gel drying process from causing the destruction of the material structure, a supercritical drying process is used. The composite wet gel can be placed in a pressure vessel and heated and pressurized to cause the liquid in the composite wet gel to undergo a phase transition into a supercritical fluid. The gas-liquid interface disappears and the surface tension no longer exists. At this time, the supercritical fluid is released from the pressure vessel to obtain a porous, disordered, low-density composite sound-absorbing material with a nano-scale continuous network structure.

[0051] On this basis, the embodiments of the present disclosure do not require the use of a binder for particle molding, which can prevent the binder from clogging the pores of the porous sound-absorbing material, and can maximize the integrity of the porous sound-absorbing material's own pore structure, thereby maintaining good sound absorption capabilities.

[0052] In addition, in the composite sound-absorbing material of the embodiment of the present disclosure, the structural reinforcement fibers and the porous sound-absorbing material are combined, interwoven and filled with each other through the nanoparticles to form a relatively tight whole. The porous zeolite powder is embedded in the pores of the aerogel or attached to its surface. When cutting, this tight combination can reduce the zeolite powder from falling off the aerogel matrix, so it is not easy to produce burrs or chips.

[0053] In one achievable manner, the specific surface area of ​​the composite sound-absorbing material of the embodiment of the present disclosure is greater than 500 m 2 / g. The large specific surface area and porous structure complement each other, so that after the sound waves enter the material, they will experience more reflection, scattering and friction processes in the complex pores, thus improving the sound absorption performance.

[0054] The present disclosure also provides a composite sound-absorbing material. Figure 2 FIG. 2 shows a schematic cross-sectional structure diagram of a composite sound-absorbing material provided by an embodiment of the present disclosure. Figure 2 As shown, the composite sound-absorbing material of the embodiment of the present disclosure includes aerogel 210 and structural reinforcement fibers 220 and porous sound-absorbing materials 230 uniformly dispersed in the aerogel 210. The composite sound-absorbing material is a material with a three-dimensional network structure formed by aerogel as a connecting unit, structural reinforcement fibers as a basic skeleton, and porous zeolite powder as functional particles. The shape of the composite sound-absorbing material may include block or sheet.

[0055] The present disclosure also provides an electronic device, which includes a speaker cavity filled with an acoustic enhancement material block according to the present disclosure. The electronic device may include at least one of a smartphone, a tablet computer, a laptop computer, a smart watch, VR, and AR.

[0056] In order to verify the effect of the composite sound-absorbing material provided by the embodiment of the present disclosure, the embodiment of the present disclosure is demonstrated by comparing the embodiment with a comparative example.

[0057] In the following examples, the drying gas for supercritical drying is CO2. (Using CO2 as the drying medium, its critical temperature is only 31°C, which belongs to the low-temperature supercritical drying technology, which reduces the critical pressure and temperature during drying, reduces the existing danger, and realizes the drying of the gel.)

[0058] Embodiment 1

[0059] The first embodiment of the present disclosure provides a composite sound-absorbing material, and the preparation method thereof comprises the following steps:

[0060] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the structural reinforcement fiber accounts for 6.00%, the absolute dry mass of the porous sound-absorbing material accounts for 52%, and the absolute dry mass of the aerogel sol liquid accounts for 42%. Among them, the structural reinforcement fiber is selected from high-strength and high-modulus aramid fiber with good water dispersibility and a fiber length of 1 mm. The porous sound-absorbing material is selected from MFI zeolite molecular sieve with an average particle size of 200 nm, including micropores with a pore size of 0.50 nm and mesopores with a pore size of 10 nm. The aerogel sol liquid is selected from SiO2 aerogel sol liquid.

[0061] The first step is to prepare an aerogel composite sol solution: according to the above formula, the structural reinforcement fiber and the porous sound-absorbing material are successively dispersed in the SiO2 aerogel sol solution at a stirring speed of 150 r / min to obtain an aerogel composite sol solution.

[0062] The second step is to prepare the composite wet gel: the composite wet gel of the first step is ultrasonically dispersed, and a condensation reaction is carried out under the condition of pH 7-9 to complete the gelation process and form a composite wet gel.

[0063] The third step is to prepare a composite sound-absorbing material: the composite wet gel obtained in the second step is dried in a supercritical fluid drying device at 31° C. and 5 MPa for 16 h to remove the solvent in the wet gel to obtain a composite sound-absorbing material.

[0064] Embodiment 2

[0065] Embodiment 2 of the present disclosure provides a composite sound-absorbing material, and a preparation method thereof comprises the following steps:

[0066] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the structural reinforcement fiber accounts for 4.00%, the absolute dry mass of the porous sound-absorbing material accounts for 66%, and the absolute dry mass of the aerogel sol liquid accounts for 30%. Among them, the structural reinforcement fiber is selected from high-strength and high-modulus aramid fiber with good water dispersibility and a fiber length of 1.5 mm. The porous sound-absorbing material is selected from ZSM-5 zeolite molecular sieve with an average particle size of 280 nm, including micropores with a pore size of 0.5 nm and mesopores with a pore size of 10 nm. The aerogel sol liquid is selected from Fe2O3 aerogel sol liquid.

[0067] The first step is to prepare an aerogel composite sol solution: according to the above formula, the structural reinforcement fiber and the porous sound-absorbing material are successively dispersed in the Fe2O3 aerogel sol solution at a stirring speed of 170r / min to obtain an aerogel composite sol solution.

[0068] The second step is to prepare the composite wet gel: the composite wet gel of the first step is ultrasonically dispersed, and a condensation reaction is carried out under the condition of pH 7-9 to complete the gelation process and form a composite wet gel.

[0069] The third step is to prepare a composite sound-absorbing material: the composite wet gel obtained in the second step is dried at 55° C. for 42 hours to remove the solvent in the wet gel to obtain a composite sound-absorbing material.

[0070] Embodiment 3

[0071] Embodiment 3 of the present disclosure provides a composite sound-absorbing material, and a preparation method thereof comprises the following steps:

[0072] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the structural reinforcement fiber accounts for 4%, the absolute dry mass of the porous sound-absorbing material accounts for 66%, and the absolute dry mass of the aerogel sol liquid accounts for 30%. Among them, the structural reinforcement fiber is selected from high-strength and high-modulus aramid fiber with good water dispersibility and a fiber length of 1.5 mm. The porous sound-absorbing material is selected from ZSM-5 zeolite molecular sieve with an average particle size of 280 nm, including micropores with a pore size of 0.50 nm and mesopores with a pore size of 10 nm. The aerogel sol liquid is selected from Fe2O3 aerogel sol liquid.

[0073] The first step is to prepare an aerogel composite sol solution: according to the above formula, the structural reinforcement fiber and the porous sound-absorbing material are successively dispersed in the Fe2O3 aerogel sol solution at a stirring speed of 170r / min to obtain an aerogel composite sol solution.

[0074] The second step is to prepare the composite wet gel: the composite wet gel of the first step is ultrasonically dispersed, and a polycondensation reaction is carried out under the condition of pH 7-9 to complete the gelation process to form a composite wet gel.

[0075] The third step is to prepare a composite sound-absorbing material: the composite wet gel obtained in the second step is dried in a supercritical fluid drying device at 31° C. and 5 MPa for 16 h to remove the solvent in the wet gel to obtain a composite sound-absorbing material.

[0076] Embodiment 4

[0077] Embodiment 4 of the present disclosure provides a composite sound-absorbing material, and a preparation method thereof comprises the following steps:

[0078] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the structural reinforcement fiber accounts for 7%, the absolute dry mass of the porous sound-absorbing material accounts for 55%, and the absolute dry mass of the aerogel sol liquid accounts for 38%. Among them, the structural reinforcement fiber is selected from high-strength and high-modulus ultra-high molecular weight polyethylene fiber with good water dispersibility and a fiber length of 2mm. The porous sound-absorbing material is selected from FER structure zeolite molecular sieve with an average particle size of 340nm, including micropores with a pore size of 0.50nm and mesopores with a pore size of 10nm. The aerogel sol liquid is selected from Al2O3 aerogel sol liquid.

[0079] The first step is to prepare an aerogel composite sol solution: according to the above formula, polyethylene fibers and FER structure zeolite molecular sieves are successively dispersed in the Al2O3 aerogel sol solution at a stirring speed of 175 r / min to obtain an aerogel composite sol solution.

[0080] The second step is to prepare the composite wet gel: the composite wet gel of the first step is ultrasonically dispersed, and a condensation reaction is carried out under the condition of pH 7-9 to complete the gelation process and form a composite wet gel.

[0081] The third step is to prepare a composite sound-absorbing material: the composite wet gel obtained in the second step is dried at 60° C. for 35 hours to remove the solvent in the wet gel to obtain a composite sound-absorbing material.

[0082] Embodiment 5

[0083] Embodiment 5 of the present disclosure provides a composite sound-absorbing material, and a preparation method thereof comprises the following steps:

[0084] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the structural reinforcement fiber accounts for 7%, the absolute dry mass of the porous sound-absorbing material accounts for 55%, and the absolute dry mass of the aerogel sol liquid accounts for 38%. Among them, the structural reinforcement fiber is selected from high-strength and high-modulus ultra-high molecular weight polyethylene fiber with good water dispersibility and a fiber length of 2mm. The porous sound-absorbing material is selected from FER structure zeolite molecular sieve with an average particle size of 340nm, including micropores with a pore size of 0.50nm and mesopores with a pore size of 10nm. The aerogel sol liquid is selected from Al2O3 aerogel sol liquid.

[0085] The first step is to prepare an aerogel composite sol solution: according to the above formula, polyethylene fibers and FER structure zeolite molecular sieves are successively dispersed in the Al2O3 aerogel sol solution at a stirring speed of 175 r / min to obtain an aerogel composite sol solution.

[0086] The second step is to prepare the composite wet gel: the composite wet gel of the first step is ultrasonically dispersed, and a condensation reaction is carried out under the condition of pH 7-9 to complete the gelation process and form a composite wet gel.

[0087] The third step is to prepare a composite sound-absorbing material: the composite wet gel obtained in the second step is dried in a supercritical fluid drying device at 31° C. and 5 MPa for 16 h to remove the solvent in the wet gel to obtain a composite sound-absorbing material.

[0088] Embodiment 6

[0089] Embodiment 6 of the present disclosure provides a composite sound-absorbing material, and a preparation method thereof comprises the following steps:

[0090] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the structural reinforcement fiber accounts for 10%, the absolute dry mass of the porous sound-absorbing material accounts for 47%, and the absolute dry mass of the aerogel sol liquid accounts for 43%. Among them, the structural reinforcement fiber is selected from high-strength and high-modulus basalt fiber with good water dispersibility and a fiber length of 2.5 mm. The porous sound-absorbing material is selected from MOR zeolite molecular sieve with an average particle size of 425 nm, including micropores with a pore size of 0.50 nm and mesopores with a pore size of 10 nm. The aerogel sol liquid is selected from NiO3 aerogel sol liquid.

[0091] The first step is to prepare an aerogel composite sol solution: according to the above formula, basalt fiber and MOR zeolite molecular sieve are successively dispersed in SiO2 aerogel sol solution at a stirring speed of 180r / min to obtain an aerogel composite sol solution.

[0092] The second step is to prepare the composite wet gel: the composite wet gel of the first step is ultrasonically dispersed, and a condensation reaction is carried out under the condition of pH 7-9 to complete the gelation process and form a composite wet gel.

[0093] The third step is to prepare a composite sound-absorbing material: the composite wet gel obtained in the second step is dried at 80° C. for 29 hours to remove the solvent in the wet gel to obtain a composite sound-absorbing material.

[0094] Embodiment 7

[0095] Embodiment 7 of the present disclosure provides a composite sound-absorbing material, and a preparation method thereof comprises the following steps:

[0096] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the structural reinforcement fiber accounts for 10%, the absolute dry mass of the porous sound-absorbing material accounts for 47%, and the absolute dry mass of the aerogel sol liquid accounts for 43%. Among them, the structural reinforcement fiber is selected from high-strength and high-modulus basalt fiber with good water dispersibility and a fiber length of 2.5 mm. The porous sound-absorbing material is selected from X-type zeolite molecular sieve with an average particle size of 500 nm, including micropores with a pore size of 0.50 nm and mesopores with a pore size of 10 nm. The aerogel sol liquid is selected from SiO2 aerogel sol liquid.

[0097] The first step is to prepare an aerogel composite sol solution: according to the above formula, basalt fiber and X-type zeolite molecular sieve are successively dispersed in the SiO2 aerogel sol solution at a stirring speed of 200 r / min to obtain an aerogel composite sol solution.

[0098] The second step is to prepare the composite wet gel: the composite wet gel of the first step is ultrasonically dispersed, and a condensation reaction is carried out under the condition of pH 7-9 to complete the gelation process and form a composite wet gel.

[0099] The third step is to prepare a composite sound-absorbing material: the composite wet gel obtained in the second step is dried in a supercritical fluid drying device at 31° C. and 5 MPa for 16 h to remove the solvent in the wet gel to obtain a composite sound-absorbing material.

[0100] Comparative Example 1

[0101] The present disclosure provides a composite sound-absorbing material in a comparative example 1, and the preparation method thereof comprises the following steps:

[0102] Taking the total weight of the composite sound-absorbing material as 100%, the absolute dry mass of the reinforcing fiber accounts for 4%, and the absolute dry mass of the acoustic enhancement particles accounts for 96%. Among them, the reinforcing fiber is composed of water-dispersible chemical synthetic fiber and thermal bonding fiber. The water-dispersible chemical synthetic fiber is aramid fiber, accounting for 65% of the absolute dry mass; the thermal bonding fiber is polypropylene fiber, accounting for 35% of the absolute dry mass.

[0103] The first step is to prepare a suspension: according to the above formula, the reinforcing fibers and the sound-absorbing particles are dispersed in water in sequence to obtain a suspension.

[0104] The second step is to prepare the composite sound-absorbing material: first, the suspension is dehydrated and filtered to obtain a sheet-like sound-absorbing material, then dried at 115°C, and hot-pressed at 200°C and 2MPa for 9 minutes to obtain a composite sound-absorbing material.

[0105] The composite sound-absorbing materials prepared in the above embodiments and comparative examples were cut into a size of 10*10 mm, and then the resonant frequency offset values ​​of the composite sound-absorbing materials were tested respectively according to Section 7.4 of the group standard "Porous Sound-Absorbing Particles for Micro Speakers" (Standard No.: T / CECA 78-2022). The specific results are shown in Table 1 below.

[0106] The sound-absorbing materials in the embodiments and comparative examples were placed in a micro speaker and dropped repeatedly 100 times at a height of 1 m to observe whether there was powder loss. The acoustic efficiency of the composite sound-absorbing material per unit mass was calculated according to the formula shown below: acoustic efficiency = resonance frequency offset value / absolute dry mass of molecular sieve. The data of the composite sound-absorbing material obtained are shown in Table 1 below:

[0107] Table 1: Composite sound-absorbing material performance test data table

[0108]

[0109] As can be seen from the above table, the composite sound-absorbing material prepared by the embodiment of the present disclosure is compared with the composite sound-absorbing material prepared by the comparative example. The comparative example does not contain the aerogel of the embodiment of the present disclosure. The composite wet gel is dried by supercritical drying in the first, third, fifth and seventh embodiments, and the composite wet gel is dried by normal pressure drying in the second, fourth and sixth embodiments. Since the supercritical drying method is easier to maintain the three-dimensional network structure of the aerogel and avoid the defects and collapse of the gel structure, it is easier to maintain a higher specific surface area and porosity. Moreover, compared with the third embodiment, the resonance frequency offset value and acoustic efficiency of the composite sound-absorbing material provided in the first comparative example are lower, and after testing, the composite sound-absorbing material prepared in the first comparative example is obviously observed to have the phenomenon of sound-absorbing particles falling off and burrs easily generated during cutting. However, the sound-absorbing materials prepared in the first to seventh embodiments of the present disclosure do not have the phenomenon of sound-absorbing particles and aerogel falling off, and burrs are not easily generated during cutting. Therefore, the composite sound-absorbing material provided by the embodiment of the present disclosure has better strength and stability. In addition, the composite sound-absorbing material of the embodiment of the present disclosure can greatly reduce the use of adhesives, and significantly reduce the damage to the sound absorption performance caused by the clogging of the pore structure of the porous sound-absorbing material by the adhesive.

[0110] Additionally, as used herein, "or" used in a list of items beginning with "at least one" indicates a separate list, so that, for example, a list of "at least one of A, B, or C" means A or B or C, or AB or AC or BC, or ABC (i.e., A and B and C). Furthermore, the word "exemplary" does not mean that the example described is preferred or better than other examples.

[0111] It should also be noted that in the system and method of the present disclosure, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present disclosure.

[0112] Various changes, substitutions, and modifications of the techniques described herein may be made without departing from the teachings defined by the appended claims. Furthermore, the scope of the claims of the present disclosure is not limited to the specific aspects of the processes, machines, manufactures, compositions of events, means, methods, and actions described above. Currently existing or later to be developed processes, machines, manufactures, compositions of events, means, methods, or actions that perform substantially the same functions or achieve substantially the same results as the corresponding aspects described herein may be utilized. Thus, the appended claims include such processes, machines, manufactures, compositions of events, means, methods, or actions within their scope.

[0113] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0114] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present disclosure to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A method for preparing a composite sound-absorbing material, characterized in that: include: The structural reinforcement fiber and the porous sound-absorbing material are uniformly dispersed in the aerogel sol liquid to obtain an aerogel composite sol liquid; Performing a gelation process on the aerogel composite sol liquid to obtain a composite wet gel; The composite wet gel is dried to obtain a composite sound-absorbing material.

2. The method for preparing the composite sound-absorbing material according to claim 1, characterized in that: The specific surface area of ​​the composite sound-absorbing material is greater than 500m 2 / g.

3. The method for preparing the composite sound-absorbing material according to claim 1, characterized in that: The drying process includes supercritical drying process and / or normal pressure drying.

4. The method for preparing the composite sound-absorbing material according to claim 3, characterized in that: If the drying process is a supercritical drying process, the composite wet gel is dried to obtain a composite sound-absorbing material block, comprising: The composite wet gel is placed in a pressure container and heated and pressurized to make the liquid in the composite wet gel undergo phase change and be converted into a supercritical fluid, thereby obtaining a composite sound-absorbing material.

5. The method for preparing the composite sound-absorbing material according to claim 3, characterized in that: The process conditions of the supercritical drying process include: the supercritical drying temperature is 35°C to 40°C, the supercritical drying pressure is 4.5MPa to 5.5MPa, and the supercritical drying time is 15h to 17h; The process conditions of the atmospheric pressure drying include: the atmospheric pressure drying temperature is 40° C. to 80° C., and the atmospheric pressure drying time is 2 h to 50 h.

6. The method for preparing the composite sound-absorbing material according to claim 1, characterized in that: In the composite sound-absorbing material, the mass ratio of the porous sound-absorbing material, the structural reinforcement fiber and the aerogel sol solution is (30-66): (4-15): (30-55).

7. The method for preparing a composite sound-absorbing material according to any one of claims 1 to 6, characterized in that: The strength of the structural reinforcement fiber is ≥10CN / dkex, and the modulus of the structural reinforcement fiber is ≥200CN / dkex.

8. The method for preparing a composite sound-absorbing material according to any one of claims 1 to 6, characterized in that: The structural reinforcement fiber comprises at least one of carbon fiber, aramid fiber, ultra-high molecular weight polyethylene fiber and basalt fiber; The aerogel sol liquid includes at least one of SiO2 aerogel sol liquid, Al2O3 aerogel sol liquid, Fe2O3 aerogel sol liquid and NiO3 aerogel sol liquid.

9. The method for preparing a composite sound-absorbing material according to any one of claims 1 to 6, characterized in that: The porous sound-absorbing material comprises zeolite molecular sieve, and the particle size of the zeolite molecular sieve is 20nm-500nm.

10. A composite sound-absorbing material, characterized in that: The composite sound-absorbing material is prepared according to the preparation method of any one of claims 1 to 9, wherein the composite sound-absorbing material is a three-dimensional network structure, and the composite sound-absorbing material comprises aerogel and structural reinforcement fibers and porous sound-absorbing materials uniformly dispersed in the aerogel.

11. An electronic device, characterized in that: The electronic device comprises a speaker cavity, and the speaker cavity is filled with the composite sound-absorbing material according to claim 10.

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