Diaphragm material, and preparation method therefor and use thereof
By mixing and dehydrating high-modulus fibers with first fibers and molding, a lightweight, high-strength, hydrophobic and flame-retardant diaphragm material was prepared, which solved the problems of poor waterproof performance, low strength, flammability and high density of paper-based diaphragm materials, and achieved the effect of high sensitivity and high frequency driving.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SONGSHAN LAKE MATERIALS LAB
- Filing Date
- 2026-01-23
- Publication Date
- 2026-07-30
AI Technical Summary
Existing paper-based diaphragm materials have poor waterproof performance, low strength, are flammable, have high density, and low modulus, resulting in low sensitivity and poor frequency drive.
High-modulus fibers such as PBO fibers, aramid fibers, and carbon fibers are mixed with the first fiber, and the diaphragm material is prepared by dehydration molding and compression molding. This avoids the use of adhesives and utilizes the hydrophobic properties and high modulus characteristics of high-modulus fibers to fill pores and improve strength and water resistance.
A lightweight and high-strength diaphragm material was prepared with a density of less than 0.86 g/cm3 and a modulus as high as 10 GPa. It has good hydrophobicity and flame retardancy, can produce sound quickly and remain stable at high temperatures, and is suitable for use in high-end loudspeakers.
Smart Images
Figure PCTCN2026074626-FTAPPB-I100001
Abstract
Description
A diaphragm material, its preparation method and application
[0001] Cross-reference of related applications
[0002] This application claims priority to Chinese Patent Application No. 202510124290.9, filed on January 26, 2025, entitled "A diaphragm material and its preparation method and application", the entire contents of which are incorporated herein by reference. Technical Field
[0003] This application belongs to the field of diaphragm preparation technology, specifically relating to a diaphragm material, its preparation method, and its application. Background Technology
[0004] An ideal diaphragm should possess the following three characteristics: 1. Low density, enabling rapid sound production; 2. High strength (modulus), allowing effective vibration under different driving frequencies; 3. High damping, absorbing noise during vibration and ensuring sound reproduction. Paper-based diaphragms are widely used due to these characteristics. Current technologies for preparing paper-based diaphragms generally use plant fibers as raw materials, further adding high-modulus fibers (such as carbon fiber and aramid fiber) to increase the modulus. However, resin binders are needed to improve the bonding strength between the plant fibers and the high-modulus fibers. The resin binder increases the density of the paper-based diaphragm; high density increases the diaphragm's weight, affecting frequency drive and resulting in low diaphragm sensitivity.
[0005] Meanwhile, plant fibers have a large number of hydroxyl groups on their surface, making them hydrophilic. Furthermore, the pores between the fibers make paper-based diaphragm materials prone to moisture absorption and deformation, leading to reduced strength. Current technologies further incorporate waterproofing agents to improve the water resistance of paper-based diaphragm materials, but this process is cumbersome. Additionally, paper-based diaphragm materials are flammable. Summary of the Invention
[0006] Therefore, the technical problem to be solved by this application is to overcome the defects of paper-based diaphragm materials in the prior art, such as poor waterproof performance, low strength, flammability, high density, and low modulus, so as to provide a diaphragm material, its preparation method and application.
[0007] Therefore, this application provides the following technical solution.
[0008] This application provides a method for preparing a diaphragm material, comprising the following steps:
[0009] High-modulus fibers and the first fiber are mixed, dehydrated, molded, and pressed to obtain the diaphragm material;
[0010] The first fiber includes at least one of a first aramid fiber, a polyester fiber, and a polyacrylonitrile fiber.
[0011] The diaphragm material can be prepared using conventional methods in the art that include dehydration molding and compression molding steps, and this application does not make specific limitations; for example, wet papermaking or pulp molding.
[0012] High-modulus fibers refer to synthetic fibers with a strength greater than 10 CN / dkex and a modulus greater than 200 CN / dkex.
[0013] In one optional embodiment, the high-modulus fiber includes at least one of PBO fiber, second aramid fiber, carbon fiber, ultra-high molecular weight polyethylene fiber, silicon carbide fiber, and alumina fiber.
[0014] The second aramid fiber is a micron-sized aramid chopped fiber, which refers to a fiber with a length of 1-10 mm;
[0015] The first aramid fibers all have nanostructures;
[0016] Ultra-high molecular weight polyethylene fiber refers to fiber spun from polyethylene with a molecular weight between 1 million and 8 million.
[0017] Aramid pulp refers to a thin film-like ultrafine fiber formed by mixing aramid meta-aramid stock solution with a certain proportion of precipitation solvent and solidifying it under shearing action; the aramid pulp can be obtained through commercial channels or conventional methods in the art, and this application does not make specific limitations;
[0018] fibrillated aramid fiber refers to para-aramid short-cut fibers that have a large number of nano-sized microfibers exposed on their surface after mechanical treatment; the fibrillated aramid fiber can be obtained through commercial channels or conventional methods in the art, and this application does not make any specific limitation.
[0019] Aramid nanofibers refer to nano-sized aramid fibers prepared by methods such as electrospinning, deprotonation, or polymerization-induced self-assembly; the electrospinning method, deprotonation method, and polymerization-induced self-assembly method can all be carried out using conventional steps in the art, and this application does not make specific limitations;
[0020] In one alternative embodiment, the mass ratio of the high-modulus fiber to the first fiber is (1-6):(4-9).
[0021] In one optional embodiment, the high-modulus fiber includes at least two of PBO fiber, second aramid fiber, carbon fiber, ultra-high molecular weight polyethylene fiber, silicon carbide fiber, and alumina fiber.
[0022] In one alternative embodiment, the first fiber comprises at least two of a first aramid fiber, polyester fiber, and polyacrylonitrile fiber.
[0023] In one optional embodiment, the first aramid fiber includes at least one of aramid pulp, fibrillated aramid fiber, and aramid nanofiber.
[0024] Optionally, the first aramid fiber includes at least two of aramid pulp, fibrillated aramid fiber, and aramid nanofiber. For example, the first aramid fiber includes aramid pulp and fibrillated aramid fiber, fibrillated aramid fiber and aramid nanofiber, aramid pulp and aramid nanofiber, etc.
[0025] In one alternative embodiment, the high-modulus fiber comprises PBO fiber and carbon fiber;
[0026] In one alternative embodiment, the first aramid fiber comprises aramid nanofibers and aramid pulp.
[0027] In one optional embodiment, the mixture yields a fiber suspension with a concentration of 0.01-0.1 wt%.
[0028] In one alternative embodiment, the molding temperature is 100-400°C.
[0029] It should be noted that the preferred molding temperature for polyester fiber and polyacrylonitrile fiber is 150-180℃; the preferred molding temperature for first aramid fiber is 280-400℃.
[0030] In one optional embodiment, the dehydration and forming process yields a wet paper web, which is then dried to obtain a diaphragm base paper.
[0031] Optionally, the drying temperature is 80-120°C;
[0032] Optionally, the moisture content of the diaphragm base paper is 50-90 wt%.
[0033] This application also provides a diaphragm material prepared according to the above-described preparation method.
[0034] In one optional embodiment, the modulus of the diaphragm material is 7.2-10 GPa;
[0035] In one optional embodiment, the density of the diaphragm material is ≤0.86 g / cm³. 3 ;
[0036] In one alternative embodiment, the limiting oxygen index of the diaphragm material is ≥27%.
[0037] This application also provides the application of the diaphragm material prepared by the above method in vehicle loudspeakers, audio loudspeakers or headphones.
[0038] The shape and size of the diaphragm material are determined according to the needs of the field, and the shape includes, but is not limited to, dome, plate, paper cone, etc.
[0039] The technical solution of this application has the following advantages:
[0040] 1. The method for preparing the diaphragm material provided in this application includes the following steps: mixing high-modulus fibers and a first fiber, dehydrating and molding, and then molding to obtain the diaphragm material; the first fiber includes at least one of aramid fiber, polyester fiber, and polyacrylonitrile fiber. This application can obtain a lightweight, high-strength diaphragm material by using high-modulus fibers and a first fiber, without the need for additional binders. The process is simple, and the resulting diaphragm is lightweight, has a low density, and a moderate loss factor (0.07-0.1), which can effectively absorb noise to ensure excellent sound reproduction; the high modulus can reach 10 GPa, ensuring effective sound generation during use; and the low density (≤0.86 g / cm³) 3 It can produce sound quickly; the high-modulus fiber and the first fiber used in this application have good hydrophobic properties. The first fiber can soften under molding and act as a binder, and fill the pores between the high-modulus fibers to prevent water molecules from penetrating and the diaphragm from absorbing moisture and deforming. The water resistance rating is ≥IPX7. In addition, the diaphragm material prepared in this application has high temperature resistance at 150-350℃, a limiting oxygen index ≥27%, and flame-retardant properties, which meets the requirements of high-end loudspeakers for high temperature resistance and flame retardancy. Detailed Implementation
[0041] The following embodiments are provided to better understand this application and are not limited to the preferred embodiments described herein. They do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining features of this application with other prior art, falls within the scope of protection of this application.
[0042] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.
[0043] Example 1
[0044] This embodiment provides a method for preparing a diaphragm material, including the following steps:
[0045] (1) PBO fiber and fibrillated aramid fiber are mixed at a mass ratio of 1:4, and then placed in a fiber dissociation machine with water and stirred to disperse, so as to obtain a fiber suspension with a concentration of 0.01 wt%.
[0046] (2) The fiber suspension is transferred to the forming wire, dehydrated to form a wet paper web, and dried in an oven at 102°C. After the moisture evaporates, the diaphragm base paper is obtained with a water content of 80wt%.
[0047] (3) The diaphragm base paper is molded at 320°C using a molding machine to obtain the diaphragm material.
[0048] Example 2
[0049] This embodiment provides a method for preparing a diaphragm material, including the following steps:
[0050] (1) PBO fiber and aramid pulp are mixed at a mass ratio of 1:1.5, and then placed in a fiber dissociation machine with water added and stirred to disperse the mixture, so as to obtain a fiber suspension with a concentration of 0.03 wt%.
[0051] (2) The fiber suspension is transferred to the forming wire, dehydrated to form a wet paper web, and dried in an oven at 100°C. After the moisture evaporates, the diaphragm base paper is obtained with a moisture content of 70%.
[0052] (3) The diaphragm base paper is molded at 300°C using a molding machine to obtain the diaphragm material.
[0053] Example 3
[0054] This embodiment provides a method for preparing a diaphragm material, including the following steps:
[0055] (1) PBO fibers and aramid nanofibers are mixed at a mass ratio of 1.5:1, placed in a fiber dissociation machine, and water is added and stirred to disperse the mixture to obtain a fiber suspension with a concentration of 0.05 wt%.
[0056] (2) The fiber suspension is transferred to the forming wire, dehydrated to form a wet paper web, and dried in an oven at 105°C. After the moisture evaporates, the diaphragm base paper is obtained with a moisture content of 60%.
[0057] (3) Use a molding machine to mold the diaphragm base paper at 280°C to obtain the diaphragm material.
[0058] Example 4
[0059] This embodiment provides a method for preparing a diaphragm material. The only difference from Embodiment 1 is that alumina fibers are used instead of PBO fibers in Embodiment 1.
[0060] Example 5
[0061] This embodiment provides a method for preparing a diaphragm material, including the following steps:
[0062] (1) Aramid fiber and aramid pulp are mixed at a mass ratio of 2:3, and then placed in a fiber dissociation machine with water and stirred to disperse, so as to obtain a fiber suspension with a concentration of 0.03 wt%.
[0063] (2) The fiber suspension is transferred to the forming wire, dehydrated to form a wet paper web, and dried in an oven at 100°C. After the moisture evaporates, the diaphragm base paper is obtained with a moisture content of 70%.
[0064] (3) The diaphragm base paper is molded at 310°C using a molding machine to obtain the diaphragm material.
[0065] Example 6
[0066] This embodiment provides a method for preparing a diaphragm material. The only difference from Embodiment 1 is that silicon carbide fiber is used instead of PBO fiber in Embodiment 1.
[0067] Example 7
[0068] This embodiment provides a method for preparing a diaphragm material. Compared with Example 1, the only difference is that PBO fiber, carbon fiber, aramid pulp and aramid nanofiber are mixed in a mass ratio of 1:1:4:4 instead of PBO fiber and fibrillated aramid fiber in a mass ratio of 1:4 in Example 1.
[0069] Example 8
[0070] This embodiment provides a method for preparing a diaphragm material, including the following steps:
[0071] (1) Carbon fiber and aramid pulp are mixed at a mass ratio of 1:1, placed in a fiber dissociation machine, water is added and stirred to disperse, and a fiber suspension is obtained. The concentration of the fiber suspension is 0.01 wt%.
[0072] (2) The fiber suspension is transferred to the forming wire, dehydrated to form a wet paper web, and dried in an oven at 102°C. After the moisture evaporates, the diaphragm base paper is obtained with a water content of 80wt%.
[0073] (3) The diaphragm base paper is molded at 320°C using a molding machine to obtain the diaphragm material.
[0074] Comparative Example 1
[0075] This comparative example provides a method for preparing a diaphragm material. Compared with Example 1, the only difference is that in step (1) of this comparative example, an adhesive (epoxy resin) is added. Based on the total mass of PBO fiber and fibrillated aramid fiber, the amount of adhesive added is 20 wt%.
[0076] Comparative Example 2
[0077] This comparative example provides a method for preparing a diaphragm material. The only difference from Example 1 is that polyethylene fiber is used instead of fibrillated aramid fiber by mass; the molecular weight of polyethylene fiber is 100,000-250,000.
[0078] Comparative Example 3
[0079] This comparative example provides a method for preparing a diaphragm material. Compared with Comparative Example 2, the only difference is that in step (1) of this comparative example, an adhesive (epoxy resin) is added. Based on the total mass of PBO fiber and polyethylene fiber, the amount of adhesive added is 20 wt%.
[0080] Test case
[0081] The performance of the diaphragm materials prepared in each embodiment and comparative example was tested, as follows:
[0082] (1) Methods for detecting elastic modulus and loss factor: The diaphragm material at 100 Hz was measured. A rectangular sample with a width of 10 mm and a length of 40 mm was cut out. The elastic modulus and loss factor were measured in tensile mode using a DMA 242E testing device (Netzsch, Germany) at a temperature of 23±2℃. The results are shown in Table 1.
[0083] (2) Density testing method: The cutting area is 100cm² 2 The diaphragm disc was weighed, and its thickness was measured using a micrometer. The density was calculated using the formula shown in Table 1. The formula is as follows: ρ=m / (A×h)
[0084] Where m is the mass of the diaphragm disc (kg); A is the area of the diaphragm disc (0.01m²). 2 h is the thickness of the diaphragm disc, in meters (m).
[0085] (3) Limiting Oxygen Index (LOI) Test Method: According to GB / T 2406-2009 "Plastics - Determination of Combustion Behavior by Oxygen Index Method", cut 15-20 strips of dry diaphragm material, each strip being 140±5 mm long and 52±0.5 mm wide. Draw a reference line 50 mm from the top of the sample. Fix the sample vertically to the axis of the combustion chamber. Adjust the oxygen / nitrogen mixture flow rate to 40±2 mm / s and purge for at least 30 seconds. After ignition, adjust the flame to spray downwards, with the lowest visible flame length approximately 16 mm. Move the flame to the top of the sample, covering the entire top surface. Ignition time: 30 seconds (during which the flame is removed and observed every 5 seconds to ensure continuous combustion).
[0086] Criteria for judging combustion behavior:
[0087] The following conditions are considered "burning" (×): the duration of flaming combustion exceeds 180 seconds; or the length of the combustion exceeds 80 mm (reaching the mark).
[0088] The following conditions are met for a non-flammable substance (○): It extinguishes immediately after being removed from the flame, or it extinguishes itself before meeting either of the above two conditions.
[0089] The limiting oxygen index (OI) is calculated according to the formula in GB / T 2406.2: OI = c f +kd
[0090] in:
[0091] c f The final oxygen concentration value (%) in a series of tests.
[0092] d: Difference (%) between used and controlled oxygen concentrations.
[0093] k: Refer to the k value table in the standard appendix based on the reaction sequence of "non-flammable" and "flammable".
[0094] The test results are shown in Table 1.
[0095] (4) Water resistance test method: According to GB / T 4208-2017 "Degrees of Protection Provided by Enclosures (IP Code)", after assembling the diaphragm into a speaker, immerse the entire speaker in water, with the bottom at least 1 meter above the water surface. The top of the sample should be at least 0.15 meters above the water surface. Duration: 30 minutes. After removing the speaker, observe whether there is water seepage or deformation on the diaphragm surface. The test results are shown in Table 1.
[0096] Table 1
[0097] The diaphragm material obtained in this application has high elastic modulus, good water resistance, moderate loss factor, low density, and limiting oxygen index >27%, which gives the diaphragm material excellent sound reproduction, rapid sound generation, and flame retardancy.
[0098] Adding a binder to Comparative Example 1 resulted in an increase in the density of the diaphragm material and a decrease in its modulus and flame retardancy. Comparative Example 2, which used thermoplastic resin to replace the first fiber, showed a significant decrease in the modulus and flame retardancy of the diaphragm material and an increase in density. Comparative Example 3, which added a binder to Comparative Example 2, showed only a limited improvement in elastic modulus and an increase in density.
[0099] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A method for preparing a diaphragm material, characterized in that, Includes the following steps: High-modulus fiber and first fiber are mixed, dehydrated and molded to obtain diaphragm material; The first fiber includes at least one of a first aramid fiber, a polyester fiber, and a polyacrylonitrile fiber.
2. The preparation method according to claim 1, characterized in that, The high-modulus fiber includes at least one of PBO fiber, second aramid fiber, carbon fiber, ultra-high molecular weight polyethylene fiber, silicon carbide fiber, and alumina fiber; and / or, The mass ratio of the high modulus fiber to the first fiber is (1-6):(4-9).
3. The preparation method according to claim 2, characterized in that, The high-modulus fiber includes at least two of PBO fiber, second aramid fiber, carbon fiber, ultra-high molecular weight polyethylene fiber, silicon carbide fiber, and alumina fiber; and / or, The first fiber includes at least two of the following: a first aramid fiber, a polyester fiber, and a polyacrylonitrile fiber.
4. The preparation method according to any one of claims 1-3, characterized in that, The first aramid fiber includes at least one of aramid pulp, fibrillated aramid fiber, and aramid nanofiber; Optionally, the first aramid fiber includes at least two of aramid pulp, fibrillated aramid fiber, and aramid nanofiber.
5. The preparation method according to claim 4, characterized in that, The high-modulus fibers include PBO fibers and carbon fibers; and / or, The first aramid fiber includes aramid nanofibers and aramid pulp.
6. The preparation method according to claim 1, characterized in that, The mixture yields a fiber suspension with a concentration of 0.01-0.1 wt%; and / or, The molding temperature is 100-400℃.
7. The preparation method according to claim 1, characterized in that, After dehydration and molding, a wet paper web is obtained, which is then dried to obtain the diaphragm base paper; Optionally, the drying temperature is 80-120°C; Optionally, the moisture content of the diaphragm base paper is 50-90 wt%.
8. A diaphragm material, characterized in that, The diaphragm material prepared by the preparation method according to any one of claims 1-7.
9. The diaphragm material according to claim 8, characterized in that, The modulus of the diaphragm material is 7.2-10 GPa; and / or, The density of the diaphragm material is ≤0.86 g / cm³. 3 ; and / or, The limiting oxygen index of the diaphragm material is ≥27%.
10. The use of the diaphragm material prepared by any one of claims 1-7 in a vehicle loudspeaker, an audio loudspeaker, or headphones.