Drum paper and method of making same, loudspeaker

Abstract

The application provides a drum paper, a preparation method thereof and a loudspeaker. The drum paper comprises a drum body and a suspension edge, and the suspension edge is connected with the periphery of the drum body. The drum body comprises a first polypropylene layer, a polyimide aerogel layer and a second polypropylene layer. The first polypropylene layer is arranged on the inner surface of the polyimide aerogel layer, and the second polypropylene layer is arranged on the outer surface of the polyimide aerogel layer.

Description

Technical Field

[0001] This application belongs to the field of acoustic technology, and in particular relates to a drum paper and its preparation method, and a loudspeaker. Background Technology

[0002] The diaphragm is one of the main sound-producing components of a loudspeaker, and the sound quality of a loudspeaker is greatly affected by the diaphragm. Traditional diaphragms usually consist of a body and suspensions. Common materials for the body include paper, polymer materials, and metals. However, the body of traditional diaphragms is mostly made of a single material, making it difficult to simultaneously meet the requirements of lightweight and waterproofing. Summary of the Invention

[0003] This application provides a drum paper, its preparation method, and a loudspeaker.

[0004] In a first aspect, embodiments of this application provide a drum paper, the drum paper including a body and a suspension edge, the suspension edge being connected to the periphery of the body; the body including a first polypropylene layer, a polyimide aerogel layer and a second polypropylene layer, the first polypropylene layer being disposed on the inner surface of the polyimide aerogel layer, and the second polypropylene layer being disposed on the outer surface of the polyimide aerogel layer.

[0005] Secondly, embodiments of this application also provide a method for preparing drum paper, comprising the following steps: S100, providing a polyimide aerogel layer, a first polypropylene layer, and a second polypropylene layer; S200: The first polypropylene layer and the second polypropylene layer are respectively disposed on the inner surface and the outer surface of the polyimide aerogel layer to obtain a carcass; S300. Connect the suspended edge to the periphery of the body to obtain the drum paper.

[0006] Thirdly, embodiments of this application also provide a loudspeaker, the loudspeaker including a diaphragm, the diaphragm being the diaphragm described above, or the diaphragm being prepared by the diaphragm preparation method described above. Attached Figure Description

[0007] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this application. Those skilled in the art can obtain other drawings based on these drawings without creative effort. In the following description, the same reference numerals denote the same parts.

[0008] Figure 1 This is a schematic diagram of the structure of the paper drum provided in an embodiment of this application.

[0009] Figure 2 for Figure 1 The top view of the drum paper is shown.

[0010] Figure 3 for Figure 2 The diagram shows a cross-sectional view of the drum paper along the AA direction.

[0011] Figure 4 for Figure 3 The diagram shows an enlarged view of part B of the drum paper.

[0012] Figure 5 SEM image of the drum paper provided in the embodiments of this application.

[0013] Figure 6 This is a flowchart illustrating the method for preparing drum paper according to an embodiment of this application.

[0014] Figure 7 This is a schematic diagram of the structure of a loudspeaker provided in an embodiment of this application.

[0015] Figure 8 for Figure 7 The speaker shown is shown in top view.

[0016] Figure 9 for Figure 8 The diagram shows a cross-sectional view of the speaker along the BB direction.

[0017] Figure 10 This is a comparison graph of the frequency response curves of the speaker in Example 2 and the speaker in Comparative Example 1.

[0018] Figure 11 This is a comparison graph of the distortion curves of the speaker in Example 2 and the speaker in Comparative Example 1.

[0019] Figure 12 This is a modal simulation diagram of the loudspeaker in Example 2.

[0020] Figure 13 This is a modal simulation diagram of the loudspeaker in Comparative Example 1.

[0021] Explanation of icon numbers: 100. Drum paper; 110. Body; 111. First polypropylene layer; 112. Polyimide aerogel layer; 113. Second polypropylene layer; 114. Mesh reinforcement; 120. Suspension edge; 200. Frame; 300. Spider; 400. Voice coil; 500. Magnet assembly. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0023] In the description of this application, unless otherwise stated, directional terms such as "upper" and "lower" specifically refer to the drawing directions in the accompanying drawings. Additionally, in the description of this application, the term "comprising" means "including but not limited to". The term "exemplary" is used to mean "serving as an example, illustration, or description," and any embodiment described as "exemplary" is not necessarily to be construed as being more preferred or advantageous than other embodiments. The term "and / or" includes any and all combinations of one or more of the associated listed items. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features; thus, features defined with "first" or "second" may explicitly or implicitly include one or more of the stated features.

[0024] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range.

[0025] This application provides a paper drum 100, such as... Figures 1-5 As shown, the drum paper 100 includes a body 110 and a suspension edge 120, the suspension edge 120 being connected to the periphery of the body 110; the body 110 includes a first polypropylene (PP) layer, a polyimide (PI) aerogel layer, and a second polypropylene (PP) layer, the first polypropylene layer 111 being disposed on the inner surface of the polyimide aerogel layer 112, and the second polypropylene layer 113 being disposed on the outer surface of the polyimide aerogel layer 112.

[0026] It should be understood that the carcass 110 has a bowl-shaped structure, the inner surface of the polyimide aerogel layer 112 refers to the side of the polyimide aerogel layer 112 facing the inside of the carcass 110, and the outer surface of the polyimide aerogel layer 112 refers to the side of the polyimide aerogel layer 112 facing the outside of the carcass 110.

[0027] The phono preamplifier 100 provided in this embodiment comprises a body 110 including a polyimide aerogel layer 112, a first polypropylene layer 111, and a second polypropylene layer 113. The first polypropylene layer 111 and the second polypropylene layer 113 are respectively disposed on the inner and outer surfaces of the polyimide aerogel layer 112. Because the polyimide aerogel layer 112 has low density and the polypropylene layer has good water resistance, the body 110 exhibits excellent lightweight characteristics, effectively reducing the overall weight of the phono preamplifier 100 while maintaining its water resistance. This solves the problem that traditional phono preamplifiers using a single material body cannot simultaneously achieve both lightweight and water resistance. It is understood that reducing the overall weight of the phono preamplifier 100 helps to improve its overall curve sensitivity and enhance sound quality.

[0028] In some embodiments of this application, the thickness of the polyimide aerogel layer 112 is 0.4 mm to 0.6 mm. By controlling the thickness of the polyimide aerogel layer 112 within the range of 0.4 mm to 0.6 mm, this application can ensure the structural rigidity of the polyimide aerogel layer 112 while significantly reducing the weight per unit area of ​​the polyimide aerogel layer 112, thereby making the overall paper drum 100 lighter. For example, the thickness of the polyimide aerogel layer 112 can be 0.4mm, 0.42mm, 0.45mm, 0.48mm, 0.5mm, 0.52mm, 0.55mm, 0.58mm, 0.6mm or any range between the aforementioned two values, and can be set according to actual needs.

[0029] Optionally, the porosity of the polyimide aerogel layer 112 is 50% to 70%. By controlling the porosity of the polyimide aerogel layer 112 within the range of 50% to 70%, this application can ensure that sound waves can effectively penetrate and be reflected multiple times within the material to achieve energy dissipation (mechanical loss), while avoiding structural collapse or insufficient stiffness due to excessive porosity. Thus, while maintaining a high elastic modulus, an ideal damping ratio is obtained, unnecessary resonance and overtones are suppressed, and a balance between acoustic damping and structural stability is achieved.

[0030] For example, the porosity of the polyimide aerogel layer 112 can be 50%, 52%, 55%, 57%, 60%, 62%, 65%, 68%, 70%, or any range between two of the aforementioned values, and can be set according to actual needs.

[0031] Optionally, the thickness of the first polypropylene layer 111 and the thickness of the second polypropylene layer 113 are each independently 0.18mm to 0.22mm. By controlling the thickness of the first polypropylene layer 111 within the range of 0.18mm to 0.22mm, both the structural rigidity and waterproofness of the first polypropylene layer 111 can be guaranteed, while also contributing to the lightweighting of the paperboard 100; similarly, by controlling the thickness of the second polypropylene layer 113 within the range of 0.18mm to 0.22mm, both the structural rigidity and waterproofness of the second polypropylene layer 113 can be guaranteed, while also contributing to the lightweighting of the paperboard 100.

[0032] For example, the thickness of the first polypropylene layer 111 can be 0.18mm, 0.19mm, 0.20mm, 0.21mm, 0.22mm or any range between two of the aforementioned values; the thickness of the second polypropylene layer 113 can be 0.18mm, 0.19mm, 0.20mm, 0.21mm, 0.22mm or any range between two of the aforementioned values, and can be set according to actual needs.

[0033] In some embodiments of this application, a mesh-like reinforcing portion 114 protrudes from the inner wall surface of the carcass 110, and the mesh-like reinforcing portion 114 is arranged circumferentially along the carcass 110. It should be understood that the carcass 110 has a bowl-shaped structure, and the inner wall surface of the carcass 110 refers to the inner surface of the sidewall of the carcass 110. By protruding the mesh-like reinforcing portion 114 from the inner wall surface of the carcass 110, this application creates a reasonable support distribution, which can enhance the structural rigidity of the carcass 110, thereby effectively suppressing the splitting vibration of the paper drum 100, ensuring the stability and durability of the paper drum 100 during use, and reducing the distortion rate. Exemplarily, the mesh-like reinforcing portion 114 can be a spider web-like reinforcing portion.

[0034] Specifically, the mesh reinforcement 14 includes a plurality of annular reinforcing ribs and a plurality of strip reinforcing ribs. The plurality of annular reinforcing ribs are arranged sequentially along the height direction of the carcass 110, and the plurality of strip reinforcing ribs are arranged sequentially along the circumference of the carcass 110, and the plurality of strip reinforcing ribs intersect with the plurality of annular reinforcing ribs.

[0035] Optionally, the thickness of the mesh reinforcement 114 is 0.5mm to 1.0mm, and the width of each of the annular reinforcing ribs and the strip reinforcing ribs is independently 0.7mm to 2.0mm. This configuration allows the mesh reinforcement 114 to enhance the structural rigidity of the body 110 and improve the smoothness of the high-frequency response without significantly increasing the overall weight of the drum 100, achieving synergistic optimization of structural rigidity and acoustic response. The thickness of the mesh reinforcement 114 refers to the height of its protrusion relative to the inner wall surface of the body 110.

[0036] For example, the thickness of the mesh reinforcement 114 can be 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, or any range between two of the aforementioned values; the width of the annular reinforcing rib and the strip reinforcing rib can each be independently 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2.0mm, or any range between two of the aforementioned values, and can be set according to actual needs.

[0037] Optionally, the mesh reinforcement 114 is integrally formed with the carcass 110. The integral formation of the mesh reinforcement 114 with the carcass 110 not only simplifies the production process and improves production efficiency, but also enhances the overall structural rigidity.

[0038] This application also provides a method for preparing the drum paper 100, which can be applied to the preparation of the aforementioned drum paper 100. For example... Figure 6 As shown, the preparation method of the drum paper 100 includes the following steps: S100, providing a polyimide aerogel layer 112, a first polypropylene layer 111, and a second polypropylene layer 113; S200, The first polypropylene layer 111 and the second polypropylene layer 113 are respectively disposed on the inner surface and the outer surface of the polyimide aerogel layer 112 to obtain the carcass 110; S300, Connect the suspension edge 120 to the periphery of the body 110 to obtain the drum paper 100.

[0039] The method for preparing the drum paper 100 provided in this application embodiment involves setting the body 110 to include a polyimide aerogel layer 112, a first polypropylene layer 111, and a second polypropylene layer 113. The first polypropylene layer 111 and the second polypropylene layer 113 are respectively disposed on the inner and outer surfaces of the polyimide aerogel layer 112. Since the polyimide aerogel layer 112 has a low density and the polypropylene layer has good water resistance, the body 110 has good lightweight characteristics, effectively reducing the overall weight of the drum paper 100 while ensuring the water resistance of the drum paper 100. This solves the problem that traditional drum paper 100 using a single material body cannot simultaneously meet the requirements of lightweight and water resistance.

[0040] In some embodiments of this application, the polyimide aerogel layer 112 can be prepared by the following method: providing a polyamic acid (PAA) sol, injecting the polyamic acid sol into a molding mold, and heating and curing to form a polyamic acid wet gel; drying the polyamic acid wet gel in supercritical CO2 at a pressure of 8 MPa to 15 MPa, a temperature of 60°C to 70°C, and a drying time of 3 to 4 hours to obtain the polyimide aerogel layer 112. This application, by using supercritical CO2 drying and controlling the pressure, temperature, and time within the above ranges, can avoid the cracking defects of traditional freeze-drying, thereby increasing the yield to over 95%.

[0041] For example, the pressure of the supercritical CO2 can be 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa, 15 MPa or any two of the aforementioned values; the temperature can be 60℃, 61℃, 62℃, 63℃, 64℃, 65℃, 66℃, 67℃, 68℃, 69℃, 70℃ or any two of the aforementioned values; and the drying time can be 3 hours, 3.1 hours, 3.2 hours, 3.3 hours, 3.4 hours, 3.5 hours, 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours, 4 hours or any two of the aforementioned values, etc., and can be set according to actual needs.

[0042] Optionally, when heating and curing the polyamic acid sol, the heating temperature is 60℃~80℃, and the heating time is 1.5 hours~2.5 hours. In this way, a uniform and stable gel network can be constructed without structural damage (microcracks, collapse, or surface peeling).

[0043] For example, when heating and curing the polyamic acid sol, the heating temperature can be 60℃, 62℃, 65℃, 68℃, 70℃, 72℃, 75℃, 78℃, 80℃ or any range between two of the aforementioned values, and the heating time can be 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2.0 hours, 2.1 hours, 2.2 hours, 2.3 hours, 2.4 hours, 2.5 hours or any range between two of the aforementioned values, and can be set according to actual needs.

[0044] Optionally, a mesh reinforcement 114 is formed on the inner surface of the polyimide aerogel layer 112. Specifically, the molding mold is a bowl-shaped mold with the mesh reinforcement 114, that is, the molding mold is a bowl-shaped mold that enables the polyimide aerogel layer 112 to form the mesh reinforcement 114. It should be understood that when the polyimide aerogel layer 112 is removed from the molding mold, the preliminary shape of the body 110 has been formed, and the inner surface of the polyimide aerogel layer 112 already has the mesh reinforcement 114, which is radially and uniformly distributed.

[0045] In some embodiments of this application, the polyamic acid sol can be prepared by the following method: mixing a polyimide precursor with a solvent to obtain a polyamic acid solution, wherein the mass percentage of the polyimide precursor is 10wt%~20wt% and the mass percentage of the solvent is 80wt%~90wt%; mixing the polyamic acid solution with a crosslinking agent, and reacting to obtain a polyamic acid sol, wherein the mass percentage of the crosslinking agent is 0.5wt%~2wt%. It is understood that by controlling the mass percentage of the polyimide precursor to 10wt%~20wt% and the mass percentage of the solvent to 80wt%~90wt%, the polyamic acid solution can form a homogeneous system, which is beneficial for the uniform and stable construction of the subsequent gel network; by controlling the mass percentage of the crosslinking agent to 0.5wt%~2wt%, the reaction efficiency can be improved and gelation accelerated.

[0046] For example, the mass percentage of the polyimide precursor can be 10wt%, 11wt%, 12wt%, 13wt%, 14wt%, 15wt%, 16wt%, 17wt%, 18wt%, 19wt%, 20wt%, or any range between any two of the aforementioned values; the mass percentage of the solvent can be 80wt%, 81wt%, 82wt%, 83wt%, 84wt%, 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, 90wt%, or any range between any two of the aforementioned values; the mass percentage of the crosslinking agent can be 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1.0wt%, 1.1wt%, 1.2wt%, 1.3wt%, 1.4wt%, 1.5wt%, 1.6wt%, 1.7wt%, 1.8wt%, 1.9wt%, 2wt%, or any range between any two of the aforementioned values, and can be specifically set according to actual needs.

[0047] Optionally, the solvent may be one or more of N,N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone (NMP), and N,N-dimethylformamide (DMF).

[0048] Optionally, the crosslinking agent includes one or more of triethylamine (TEA) and N,N'-dicyclohexylcarbodiimide (DCC).

[0049] In some embodiments of this application, mixing the polyimide precursor with the solvent includes: mixing dianhydride and diamine with the solvent, wherein the molar ratio of the dianhydride to the diamine is (0.98:1~1.02):1. Exemplarily, the molar ratio of the dianhydride to the diamine can be 0.98:1, 0.99:1, 1.00:1, 1.01:1, 1.02:1, or a range between any two of the aforementioned ratios. The dianhydride can be pyromellitic dianhydride (PMDA) or 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA); the diamine can be 4,4'-diaminodiphenyl ether (ODA) or 4,4'-diaminodiphenyl sulfide (DADS).

[0050] Optionally, the step of mixing the polyimide precursor with a solvent to obtain a polyamic acid solution comprises: adding dianhydride and diamine to the solvent in a molar ratio of (0.98:1~1.02):1 under nitrogen protection, and stirring at a temperature of 20°C~30°C (e.g., 20°C, 25°C or 30°C) for 12 hours~48 hours (e.g., 12 hours, 24 hours or 48 hours) to obtain a polyamic acid solution with a solid content of 10%~20%.

[0051] In some embodiments of this application, the step of mixing the polyamic acid solution with the crosslinking agent and reacting to obtain a polyamic acid sol includes: mixing the polyamic acid solution with the crosslinking agent and reacting for 0.5 hours to 2 hours to obtain a polyamic acid sol.

[0052] For example, the reaction time between the polyamic acid solution and the crosslinking agent can be 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours, 1.0 hours, 1.1 hours, 1.2 hours, 1.3 hours, 1.4 hours, 1.5 hours, 1.6 hours, 1.7 hours, 1.8 hours, 1.9 hours, 2 hours, or any range between two of the aforementioned values, and can be set according to actual needs.

[0053] Optionally, before mixing the polyamic acid solution with the crosslinking agent, the method further includes the following step: adding a nano-reinforcing phase to the polyamic acid solution and ultrasonically dispersing it for 20 to 60 minutes. The nano-reinforcing phase is one or more of carbon nanotubes (CNTs), graphene, and silica (SiO2) nanoparticles. By adding the nano-reinforcing phase, the toughness of the subsequently obtained polyimide aerogel layer 112 can be improved. Ultrasonic dispersion can prevent the agglomeration of the polyimide precursor and the nano-reinforcing phase, thereby ensuring the uniformity of the sol and preventing local stress concentration (microscopic crack prevention) during subsequent drying.

[0054] For example, the ultrasonic dispersion time can be 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 60 minutes, or any range between two of the aforementioned values.

[0055] Optionally, after obtaining the polyamic acid sol, the pH value of the polyamic acid sol can be adjusted to 8-9 (e.g., 8, 8.5 or 9). Adjusting the pH value of the polyamic acid sol to 8-9 (weakly alkaline) is beneficial to promoting gelation.

[0056] In some embodiments of this application, step S200 includes: attaching the first polypropylene layer 111 and the second polypropylene layer 113 to the inner and outer surfaces of the polyimide aerogel layer 112 respectively by hot pressing, that is, attaching the first polypropylene layer 111 and the second polypropylene layer 113 to the inner and outer surfaces of the polyimide aerogel layer 112 respectively by hot pressing to form a sandwich structure; the temperature during hot pressing is 175℃~185℃, the pressure is 0.8Mpa~1.2Mpa, and the time is 10 minutes~15 minutes.

[0057] Specifically, step S200 includes: attaching the first polypropylene layer 111 to the inner surface of the polyimide aerogel layer 112 by hot pressing, wherein the temperature during hot pressing is 175℃~185℃, the pressure is 0.8Mpa~1.2Mpa, and the time is 10 minutes~15 minutes; and attaching the second polypropylene layer 113 to the outer surface of the polyimide aerogel layer 112 by hot pressing, wherein the temperature during hot pressing is 175℃~185℃, the pressure is 0.8Mpa~1.2Mpa, and the time is 10 minutes~15 minutes.

[0058] For example, the temperature during hot pressing can be 175℃, 176℃, 177℃, 178℃, 179℃, 180℃, 181℃, 182℃, 183℃, 184℃, 185℃, or any range between two of the aforementioned values; the pressure can be 0.8Mpa, 0.85Mpa, 0.9Mpa, 0.95Mpa, 1.0Mpa, 1.05Mpa, 1.1Mpa, 1.15Mpa, 1.2Mpa, or any range between two of the aforementioned values; and the time can be 10 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, or any range between two of the aforementioned values. The specific settings can be configured according to actual needs.

[0059] Optionally, after obtaining the carcass 110, the following steps may be included: bending the edge of the first polypropylene layer 111 of the carcass 110 downwards, and bonding and fixing the inner and outer edges of the carcass 110 with a waterproof adhesive. The waterproof adhesive may be an epoxy resin adhesive, polyurethane (PU) adhesive, silicone rubber adhesive, acrylic adhesive (such as UV-curable adhesive), cyanoacrylate (fast-drying adhesive), hot melt adhesive (EVA or PVA based), or modified silicone, etc.

[0060] In some embodiments of this application, step S300 includes: placing the body 110 into the bottom of the bonding mold, placing the overhang 120 above the body 110, closing the bonding mold, heating the bonding mold to 160°C~180°C and applying a pressure of 3MPa~8MPa, maintaining it for 30 seconds~40 seconds, and then cooling it to below 80°C to demold, thereby obtaining the drum paper 100.

[0061] The overhang 120 can be made of rubber, cloth, or paper; that is, the overhang 120 can be, but is not limited to, rubber, cloth, or paper. Specifically, the overhang 120 can be coated with a waterproof adhesive and then dried for later use. The waterproof adhesive can be epoxy resin adhesive, polyurethane (PU) adhesive, silicone rubber adhesive, acrylic ester adhesive (such as UV-cured adhesive), cyanoacrylate (fast-drying adhesive), hot melt adhesive (EVA or PVA based), or modified silicone, etc. It is important to understand that drying the overhang 120 after applying the waterproof adhesive removes solvents from the adhesive, preventing evaporation of gases and air bubbles during mold closing. It also improves the initial tack of the adhesive layer, preventing displacement of the adhesive under pressure, and prevents undried adhesive from adhering to the mold cavity, thus avoiding difficulties in demolding.

[0062] For example, after closing the bonding mold, the bonding mold can be heated to 160°C, 165°C, 170°C, 175°C or 180°C, and pressure of 3MPa, 4MPa, 5MPa, 6MPa, 7MPa or 8MPa can be applied and maintained for 30 seconds, 31 seconds, 32 seconds, 33 seconds, 34 seconds, 35 seconds, 36 seconds, 37 seconds, 38 seconds, 39 seconds or 40 seconds, etc., which can be set according to actual needs.

[0063] This application also provides a speaker, such as... Figures 7-9 As shown, the loudspeaker includes a diaphragm 100, the specific structure of which is described in the above embodiments. Since this loudspeaker employs all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated upon here.

[0064] Specifically, the loudspeaker further includes a frame 200, a spider 300, a voice coil 400, and a magnet assembly 500. The frame 200 includes a central hole, the magnet assembly 500 is mounted on the central hole, the voice coil 400 is partially disposed within the magnet assembly 500, the diaphragm 100 is disposed within the frame 200 and the suspension edge 120 of the diaphragm 100 is fixedly connected to the frame 200, the inner side of the body 110 of the diaphragm 100 is fixedly connected to the outer wall of the voice coil 400, and the spider 300 is located below the diaphragm 100 and is fixedly connected to the outer wall of the voice coil 400.

[0065] The technical solutions and effects of this application will be described in detail below through specific embodiments and comparative examples. The following embodiments are only some embodiments of this application and are not intended to limit this application.

[0066] Example 1 Example 1 provides a drum paper, the preparation method of which includes the following steps: (1) Under nitrogen protection, pyromellitic dianhydride (PMDA) and 4,4'-diaminodiphenyl ether (ODA) were added to N,N-dimethylacetamide (DMAC) at a molar ratio of 1:1 and stirred at 25°C for 24 hours to obtain a polyamic acid (PAA) solution with a solid content of 15%. (2) Add triethylamine, a crosslinking agent, to the polyamic acid solution obtained in step (1), stir for 1 hour, and after the reaction, a polyamic acid sol is obtained. Adjust the pH value of the polyamic acid sol to 8.5. (3) Inject the polyamic acid sol into a bowl-shaped molding mold, and then heat it at 70°C for 2 hours to complete the gelation and obtain a polyamic acid wet gel; (4) Place the molding mold along with the polyamic acid wet gel in supercritical CO2 (12MPa, 65℃) and dry for 4 hours to form a polyimide (PI) aerogel with a porosity of 60%. (5) Take out the cured polyimide aerogel and cut it into polyimide aerogel layers with the required diameter and thickness of 0.5 mm; (6) Two polypropylene (PP) films with a thickness of 0.2 mm are bonded to the inner and outer surfaces of the polyimide aerogel layer by hot pressing to form the first polypropylene layer and the second polypropylene layer, respectively, to obtain a sandwich structure body. The temperature during hot pressing is 180℃, the pressure is 1MPa, and the time is 12 minutes. (7) Bend the first polypropylene layer of the carcass downwards and use epoxy resin adhesive to bond and fix the inner and outer edges of the carcass to ensure the formation of a sealed carcass, so as to ensure waterproofness and airtightness. (8) Apply waterproof glue to the rubber suspension edge and let it dry for later use. Then place the prepared body into the bottom of the fitting mold, and then place the dried rubber suspension edge on top of the body. After closing the mold, raise the temperature to 170°C and apply a pressure of 5MPa for 30 seconds. Then slowly cool down to below 80°C and demold to obtain the drum paper.

[0067] Example 2 Example 2 is basically the same as Example 1, except that: the molding mold used in step (3) is a bowl-shaped molding mold with a spider web structure, and the inner surface of the polyimide aerogel layer obtained in step (5) is provided with a spider web-shaped reinforcing part.

[0068] Comparative Example 1 Comparative Example 1 provides a conventional drum paper. The conventional drum paper of Comparative Example 1 is basically the same as the drum paper of Example 1, except that the body of the conventional drum paper of Comparative Example 1 is made of polypropylene only (that is, the body of the conventional drum paper of Comparative Example 1 is made of PP material).

[0069] Loudspeakers were fabricated using the diaphragm from Example 2 and the conventional diaphragm from Comparative Example 1, respectively. The frequency response and distortion curves of each loudspeaker were then tested using KLIPPEL software. The test conditions were 1M / 1W, and the test frequency range was 20Hz~20kHz. The test results are as follows: Figure 10 and Figure 11 As shown. Modal simulations of each loudspeaker were performed using COMSOL software, and the results are as follows. Figure 12 and Figure 13 As shown.

[0070] See Figure 10 In Example 2, the use of a polyimide aerogel layer in the diaphragm resulted in a 45% reduction in overall weight compared to the conventional diaphragm in Comparative Example 1, leading to an overall improvement in frequency response of 0.8–1 dB. Furthermore, the improved material of the body 110 and the spiderweb-like reinforcement in Example 2 enhanced structural strength, suppressing the split vibration between the body and the suspension edge, thereby improving the speaker's frequency response curve in the 5 kHz–20 kHz range.

[0071] See Figure 11 In Example 2, the drum paper is designed with spider web-like reinforcements on the body, forming a reasonable support distribution. At the same time, the body uses a sandwich structure of a first polypropylene layer, a polyimide aerogel layer, and a second polypropylene layer, which effectively improves the structural stiffness of the drum paper and can effectively suppress the splitting vibration of the drum paper, thereby reducing distortion at 5kHz~12kHz.

[0072] Depend on Figure 12It can be seen that the vibration mode of the drum paper in Example 2 is stable at 8kHz, and the drum paper body does not produce significant deformation, effectively suppressing the split vibration of the drum paper, thereby improving the frequency response curve and distortion curve; Figure 13 It can be seen that the conventional drum paper in Comparative Example 1 underwent significant deformation in its vibration mode at 8kHz, resulting in segmented vibration and causing a difference between the frequency response curve and the distortion curve.

[0073] In summary, this application has the following beneficial effects: 1. The body 110 of the drum paper 100 adopts a polyimide aerogel layer 112, and a first polypropylene layer 111 and a second polypropylene layer 113 are respectively set on both sides of the polyimide aerogel layer 112, so that the body 110 has good lightweight characteristics, effectively reducing the overall weight of the drum paper 100 (reducing it by 40%~50%), while ensuring the structural strength of the drum paper 100, solving the problem that traditional paper drum paper is prone to breakage under excessive stress; 2. The sandwich structure formed by the polyimide aerogel layer 112, the first polypropylene layer 111, and the second polypropylene layer 113 gives the drum paper 100 excellent acoustic performance, effectively improves the sound quality, reduces the distortion rate, and makes the frequency response curve fluctuate by <±2dB in the range of 5kHz to 20kHz, with a distortion rate of less than 3%, thereby improving the overall sound quality level of the loudspeaker and overcoming the shortcomings of the existing drum paper in terms of dry sound quality and high distortion rate. 3. By designing a mesh reinforcement section 114 on the body 110, a reasonable support distribution is formed, which effectively improves the structural rigidity of the drum paper 100, effectively suppresses the splitting vibration of the drum paper 100, solves the problem of unreasonable design of the existing drum paper 100 reinforcement structure, and ensures the stability and durability of the drum paper 100 during use. 4. The first polypropylene layer 111 and the second polypropylene layer 113 form a good seal, which effectively prevents the diaphragm 100 from leaking air, overcomes the problems of easy air leakage and high distortion rate of the diaphragm in the prior art, and ensures the service life and reliability of the speaker. 5. The body 110 of the drum paper 100 adopts a combination design of polyimide aerogel and polypropylene materials, which optimizes the structure and enhances the function while ensuring lightweight, and solves the problem that traditional materials cannot simultaneously meet the requirements of light weight, high rigidity and moderate damping. In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0074] The foregoing has provided a detailed description of the drum paper, its preparation method, and the loudspeaker provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A type of drum paper, characterized in that, It includes a carcass and a suspension edge, the suspension edge being connected to the periphery of the carcass; the carcass includes a first polypropylene layer, a polyimide aerogel layer and a second polypropylene layer, the first polypropylene layer being disposed on the inner surface of the polyimide aerogel layer and the second polypropylene layer being disposed on the outer surface of the polyimide aerogel layer.

2. The paper drum according to claim 1, characterized in that, The inner wall surface of the carcass is provided with a mesh reinforcement portion, which is arranged along the circumference of the carcass.

3. The paper drum according to claim 2, characterized in that, The mesh reinforcement includes multiple annular reinforcing ribs and multiple strip reinforcing ribs. The multiple annular reinforcing ribs are arranged sequentially along the height direction of the carcass, and the multiple strip reinforcing ribs are arranged sequentially along the circumference of the carcass. The multiple annular reinforcing ribs intersect with the multiple strip reinforcing ribs.

4. The drum paper according to claim 3, characterized in that, The thickness of the mesh reinforcement is 0.5mm to 1.0mm, and the width of the annular reinforcing rib and the strip reinforcing rib is 0.7mm to 2.0mm respectively. And / or, the mesh reinforcement is integrally formed with the carcass.

5. The drum paper according to any one of claims 1 to 4, characterized in that, The thickness of the polyimide aerogel layer is 0.4 mm to 0.6 mm; And / or, the porosity of the polyimide aerogel layer is 50%~70%; And / or, the thickness of the first polypropylene layer and the thickness of the second polypropylene layer are each independently 0.18 mm to 0.22 mm.

6. A method for preparing drum paper, characterized in that, Includes the following steps: S100, providing a polyimide aerogel layer, a first polypropylene layer, and a second polypropylene layer; S200: The first polypropylene layer and the second polypropylene layer are respectively disposed on the inner surface and the outer surface of the polyimide aerogel layer to obtain a carcass; S300. Connect the suspended edge to the periphery of the body to obtain the drum paper.

7. The method for preparing drum paper according to claim 6, characterized in that, The polyimide aerogel layer was prepared by the following method: A polyamic acid sol is provided, which is injected into a molding mold and heated to solidify to form a polyamic acid wet gel. The polyamic acid wet gel was dried in supercritical CO2 at a pressure of 8 MPa to 15 MPa and a temperature of 60°C to 70°C for 3 to 4 hours to obtain a polyimide aerogel layer.

8. The method for preparing drum paper according to claim 7, characterized in that, When the polyamic acid sol is heated and cured, the heating temperature is 60℃~80℃ and the heating time is 1.5 hours~2.5 hours; And / or, a mesh reinforcement is formed on the inner surface of the polyimide aerogel layer.

9. The method for preparing drum paper according to claim 7, characterized in that, The polyamic acid sol was prepared by the following method: A polyimide precursor is mixed with a solvent to obtain a polyamic acid solution, wherein the mass percentage of the polyimide precursor is 10wt%~20wt% and the mass percentage of the solvent is 80wt%~90wt%. The polyamic acid solution is mixed with a crosslinking agent, and a polyamic acid sol is obtained after the reaction. The mass percentage of the crosslinking agent is 0.5wt% to 2wt%.

10. The method for preparing drum paper according to claim 9, characterized in that, The mixing of the polyimide precursor with the solvent includes: mixing dianhydride and diamine with the solvent, wherein the molar ratio of the dianhydride to the diamine is (0.98:1~1.02):1; And / or, the solvent is one or more of N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and N,N-dimethylformamide; And / or, the step of mixing the polyamic acid solution with the crosslinking agent and reacting to obtain a polyamic acid sol includes: mixing the polyamic acid solution with the crosslinking agent and reacting for 0.5 hours to 2 hours to obtain a polyamic acid sol; And / or, the crosslinking agent includes one or more of triethylamine and N,N'-dicyclohexylcarbodiimide; And / or, before mixing the polyamic acid solution with the crosslinking agent, the method further includes the following steps: adding a nano-reinforcing phase to the polyamic acid solution and ultrasonically dispersing it for 20 to 60 minutes, wherein the nano-reinforcing phase is one or more of carbon nanotubes, graphene, and silica nanoparticles.

11. The method for preparing drum paper according to claim 6, characterized in that, Step S200 includes: attaching the first polypropylene layer and the second polypropylene layer to the inner and outer surfaces of the polyimide aerogel layer respectively by hot pressing, wherein the temperature during hot pressing is 175℃~185℃, the pressure is 0.8Mpa~1.2Mpa, and the time is 10 minutes~15 minutes. And / or, step S300 includes: placing the carcass at the bottom of the bonding mold, placing the overhang above the carcass, closing the bonding mold, heating the bonding mold to 160°C~180°C and applying a pressure of 3MPa~8MPa, maintaining it for 30 seconds~40 seconds, and then cooling it to below 80°C to demold, thereby obtaining the drum paper.

12. A loudspeaker, characterized in that, Includes drum paper, wherein the drum paper is the drum paper according to any one of claims 1 to 5, or the drum paper is prepared by the method of preparing drum paper according to any one of claims 6 to 11.

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