Composite sound basin and preparation method and application thereof

Abstract

This invention provides a composite cone, its preparation method, and its application. The preparation method includes: dispersing aramid fibers in water and pulping to obtain component A; mixing component A with carbon fibers uniformly to obtain component B; subjecting the wet cone blank to a first hot pressing to obtain a first cone blank; immersing the first cone blank in an epoxy resin solution and then drying it to obtain a second cone blank; and subjecting the second cone blank to a second hot pressing to obtain the composite cone. Through the design and synergy of carbon fibers, aramid fibers, and epoxy resin, combined with a specific preparation process, the composite cone exhibits high strength and excellent waterproof and moisture-proof performance. Furthermore, this preparation method can produce composite cones with high taper and complex shapes, which, when applied to loudspeakers, can expand the frequency response range of loudspeakers, improve their weather resistance, and greatly enrich the application range of loudspeakers.

Description

Technical Field

[0001] This invention belongs to the field of loudspeaker technology, specifically relating to a composite cone, its preparation method, and its application. Background Technology

[0002] The cone is a crucial component of a loudspeaker's sound-generating unit, its primary function being to provide an accurate frequency response. Cones can be categorized by material into paper cones, metal cones, ceramic cones, PP cones, and composite material cones. Among these, paper cones are widely used due to their natural sound, low cost, and ease of processing. However, the main raw material of paper cones is plant fiber, giving them a natural hydrophilicity. This results in poor water resistance. When a paper cone absorbs moisture, its mechanical properties decrease significantly, and it becomes heavier, altering the loudspeaker's acoustic characteristics. Repeated wet-dry cycles can lead to material fatigue and even irreversible deformation and damage to the cone.

[0003] To expand the application of loudspeaker products in outdoor, underwater, marine, and jet ski fields, loudspeaker cones are required to have completely waterproof and moisture-proof properties. To achieve this goal, the industry currently uses the following methods:

[0004] (1) Use PP (polypropylene) material for the cone. PP has good waterproof and moisture-proof properties, which can meet the application of loudspeaker products in humid environments; however, PP material is not rigid enough and is not suitable for tweeters or full-range loudspeakers.

[0005] (2) Metal cones are used, with aluminum cones being the most common type. After surface treatment, aluminum cones can meet the requirements of loudspeaker products in humid environments; however, aluminum cones are expensive and, due to the limited elongation of aluminum sheets, it is impossible to form cones with large tapers and complex shapes.

[0006] (3) Waterproofing and moisture-proofing treatment of the paper cone. For example, CN110636418A discloses a speaker paper cone, its preparation method, and its application. The raw materials for preparing the speaker paper cone include pulp, cationic styrene-acrylic emulsion, and emulsified paraffin wax. The cationic styrene-acrylic emulsion and emulsified paraffin wax work synergistically to give the paper cone excellent waterproof and moisture-proof properties. Although the paper cone obtained by this method has significantly improved waterproof and moisture-proof performance compared to ordinary paper cones, and can meet the application requirements of speakers in humid environments and environments with short-term water contact, this paper cone still has a water absorption rate of 4.72%, which limits its use in more severe environments.

[0007] (4) A loudspeaker cone is formed by impregnating carbon fiber woven fabric with epoxy resin and then hot-pressing it. For example, CN115895191A discloses a method for preparing a carbon fiber cone, which, by weight, contains the following components: 90-100 parts of carbon fiber woven fabric, 7-28 parts of epoxy resin, 3-12 parts of curing agent, 0.0001-5 parts of color paste, and 0.1-1 parts of defoamer. This carbon fiber cone is thin, strong, and has good moisture resistance and environmental stability. However, the elongation of carbon fiber woven fabric is not high, making it impossible to form cones with large tapers and complex shapes, and the waterproof and moisture-proof performance of the cone is still insufficient.

[0008] Therefore, developing a cone with good waterproof and moisture-proof performance, high strength, and adaptability to various application scenarios with high taper and complex shapes is an urgent problem to be solved in this field. Summary of the Invention

[0009] To address the shortcomings of existing technologies, the present invention aims to provide a composite cone, its preparation method, and its applications. Through the design and synergy of carbon fiber, aramid fiber, and epoxy resin, combined with a specific preparation method, the resulting composite cone possesses high strength and excellent waterproof and moisture-proof properties. Simultaneously, the preparation method can produce composite cones with high taper and complex shapes. When applied to loudspeakers, the composite cone can expand the frequency response range of the loudspeaker, improve its weather resistance, and broaden its application range.

[0010] To achieve this objective, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a method for preparing a composite cone, the method comprising:

[0012] Aramid fibers were dispersed in water and pulped to obtain component A;

[0013] Component A is mixed evenly with carbon fiber to obtain component B;

[0014] An epoxy adhesive solution is provided, the epoxy adhesive solution comprising a combination of epoxy resin, curing agent and solvent;

[0015] Component B is filtered to obtain a wet soundboard embryo;

[0016] The wet cone blank is subjected to a first hot pressing to obtain a first cone blank;

[0017] The first cone blank is immersed in epoxy resin and then dried to obtain the second cone blank.

[0018] The second cone blank is subjected to a second hot pressing to obtain the composite cone.

[0019] This invention uses aramid fiber, carbon fiber, and epoxy resin as raw materials. Research revealed that both carbon fiber and aramid fiber possess high strength and high modulus, and their smooth surfaces lack active functional groups. Therefore, there are no hydrogen bonds between carbon fiber and aramid fiber, and they are difficult to intertwine and generate interlacing force. Without treatment, the resulting cone exhibits weak bonding, a loose internal structure, and may even fail to form properly. Therefore, this invention does not directly add aramid fiber; instead, it undergoes pulping treatment. This process maintains the same fiber length while introducing numerous fluffy microfibers on the fiber backbone surface, significantly increasing the degree of fibrillation. This effectively enhances the interlacing points and bonding force between aramid and carbon fiber, constructing a cone structure with carbon fiber as the supporting fiber and aramid fiber as the winding fiber.

[0020] The preparation method of the present invention includes two hot-pressing processes. The first hot pressing dehydrates and shapes the wet cone blank, resulting in a first cone blank with large inter-fiber pores, a loose structure, and a structure similar to a "bird's nest". The first cone blank is then impregnated in an epoxy resin solution, which allows the epoxy resin to fully penetrate into the cone blank, remain inside it, and adhere to the interlacing sites of carbon fibers and aramid fibers in the first cone blank. A second hot pressing is then performed to cure the epoxy resin, tightly bonding the carbon fibers and aramid fibers, reducing the cone porosity, and shaping the second cone blank to obtain the composite cone. In the second hot pressing, the epoxy resin acts as a bond between the carbon fibers and aramid fibers, and the strength of the cured epoxy resin is increased, thereby further improving the rigidity and strength of the composite cone.

[0021] In this invention, through the design and synergistic effect of carbon fiber, aramid fiber, and epoxy resin, combined with a specific preparation process, not only are the high strength and high modulus advantages of carbon fiber and aramid fiber effectively utilized, but also excellent interweaving force and high adhesion between the carbon fiber and aramid fiber are achieved. This results in a composite cone with high strength and excellent waterproof and moisture-proof performance. Furthermore, the preparation method of the composite cone provided by this invention involves dispersing carbon fiber and pulped aramid fiber in water, followed by wet molding through a mold and filter screen, which can produce composite cones with high taper and complex shapes. When applied to loudspeakers, the composite cone can expand the frequency response range of the loudspeaker, improve its weather resistance, and broaden its application in outdoor, underwater, marine, and jet ski fields, greatly enriching the application range of loudspeakers.

[0022] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0023] Preferably, the raw materials used in the preparation method include, by weight, the following:

[0024]

[0025] Specifically, the aramid fiber has a mass fraction of 85-95 parts, for example, 86 parts, 87 parts, 88 parts, 89 parts, 90 parts, 91 parts, 92 parts, 93 parts or 94 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0026] The carbon fiber has a mass fraction of 5-15 parts, for example, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts or 14 parts, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0027] The epoxy resin is in the form of 3-5 parts by weight, for example, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.2 parts, 4.5 parts or 4.8 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0028] The curing agent is 0.6-2.5 parts by weight, for example, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts or 2.4 parts, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 0.9-1.5 parts is further preferred.

[0029] As a preferred technical solution of the present invention, the carbon fiber, aramid fiber and epoxy resin are used in specific amounts to achieve synergistic effect and complementary performance, which not only effectively leverages the advantages of high strength and high modulus of carbon fiber and aramid fiber, but also improves the bonding force and adhesion between carbon fiber and aramid fiber.

[0030] Preferably, the average length of the aramid fiber is 5.5-6.5 mm, for example, it can be 5.6 mm, 5.7 mm, 5.8 mm, 5.9 mm, 6 mm, 6.1 mm, 6.2 mm, 6.3 mm or 6.4 mm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0031] Preferably, the tensile strength of the aramid fiber is 2500-3500 MPa, for example, it can be 2600 MPa, 2800 MPa, 3000 MPa, 3100 MPa, 3200 MPa, 3300 MPa or 3400 MPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0032] Preferably, the elastic modulus of the aramid fiber is 100-150 GPa, for example, it can be 105 GPa, 110 GPa, 115 GPa, 120 GPa, 125 GPa, 130 GPa, 135 GPa, 140 GPa or 145 GPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0033] Preferably, the elongation at break of the aramid fiber is 2.0%-3.0%, for example, it can be 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0034] Preferably, the density of the aramid fiber is 1.38-1.45 g / cm³. 3 For example, it can be 1.39 g / cm³. 3 1.4g / cm 3 1.41 g / cm 3 1.42g / cm 3 1.43 g / cm 3 Or 1.44 g / cm 3 As well as the specific point values ​​between the above point values, due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0035] As a preferred embodiment of the present invention, the aramid fiber has a tensile strength of 2815 MPa, an elastic modulus of 126 GPa, an elongation at break of 2.5%, and a density of 1.44 g / cm³. 3 A comparison of aramid fibers and carbon fibers shows that carbon fibers have advantages in mechanical properties, while aramid fibers have greater elongation and lower density than carbon fibers.

[0036] Preferably, the average length of the carbon fiber is 4-7 mm, for example, it can be 4.2 mm, 4.5 mm, 4.8 mm, 5 mm, 5.2 mm, 5.5 mm, 5.8 mm, 6 mm, 6.2 mm, 6.5 mm or 6.8 mm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0037] Preferably, the tensile strength of the carbon fiber is 2500-4500 MPa, for example, it can be 2800 MPa, 3000 MPa, 3500 MPa, 3500 MPa, 3800 MPa, 4000 MPa, 4200 MPa or 4400 MPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0038] Preferably, the elastic modulus of the carbon fiber is 200-300 GPa, for example, it can be 210 GPa, 220 GPa, 230 GPa, 240 GPa, 250 GPa, 260 GPa, 270 GPa, 280 GPa or 290 GPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0039] Preferably, the elongation at break of the carbon fiber is 1.3%-1.9%, for example, it can be 1.4%, 1.5%, 1.6%, 1.7% or 1.8%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0040] Preferably, the density of the carbon fiber is 1.5-2.0 g / cm³. 3 For example, it can be 1.55 g / cm³. 3 1.6g / cm 3 1.7g / cm 3 1.8g / cm 3 Or 1.9g / cm 3 As well as the specific point values ​​between the above point values, due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0041] As a preferred embodiment of the present invention, the carbon fiber has a tensile strength of 3000 MPa, an elastic modulus of 225 GPa, an elongation at break of 1.7%, and a density of 1.7 g / cm³. 3 With an average length of 4-7mm, it has high strength and high modulus. As a supporting fiber, it can effectively improve the strength and modulus of the composite cone.

[0042] Preferably, the epoxy resin comprises an epoxy laminated resin.

[0043] Preferably, the curing agent includes amine curing agents and / or phenolic curing agents.

[0044] Preferably, the amine curing agent includes any one or a combination of at least two of 1,3-cyclohexanedimethylamine, ethylene glycol bis(3-aminopropyl) ether, and polyetheramine (α-(2-aminomethylethyl)-ω-(2-aminomethylethoxy)polyethylene glycol).

[0045] Preferably, the phenolic curing agent includes bisphenol A and / or bisphenol F, with bisphenol A being more preferred.

[0046] Preferably, the curing agent comprises a combination of 1,3-cyclohexanedimethylamine, ethylene glycol bis(3-aminopropyl) ether, polyetheramine (α-(2-aminomethylethyl)-ω-(2-aminomethylethoxy)polyethylene glycol) and bisphenol A.

[0047] Preferably, the mass percentage of 1,3-cyclohexanedimethylamine in the curing agent is 30-50%, for example, it can be 32%, 35%, 38%, 40%, 42%, 45% or 48%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0048] Preferably, the mass percentage of ethylene glycol bis(3-aminopropyl) ether in the curing agent is 25-30%, for example, it can be 26%, 27%, 28% or 29%, and specific values ​​between the above points are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0049] Preferably, the bisphenol A content in the curing agent is 20-25% by mass, for example, it can be 21%, 22%, 23% or 24%, and specific values ​​between the above points are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0050] Preferably, the curing agent contains 12.5-20% polyetheramine (α-(2-aminomethylethyl)-ω-(2-aminomethylethoxy)polyethylene glycol) by mass percentage, for example, 13%, 14%, 15%, 16%, 17%, 18% or 19%, and specific values ​​between the above values ​​are not exhaustively listed in this invention for space limitations and for the sake of brevity.

[0051] For example, the curing agent can be purchased commercially, such as AY30 FAST.

[0052] Preferably, the mass ratio of epoxy resin to curing agent is 1:(0.2-0.5), for example, it can be 1:0.22, 1:0.25, 1:0.28, 1:0.3, 1:0.32, 1:0.35, 1:0.38, 1:0.4, 1:0.42, 1:0.45 or 1:0.48, etc.

[0053] As a preferred embodiment of the present invention, the epoxy resin is an epoxy laminate resin (e.g., model EL2); the curing agent is AY30 FAST, which has low polarity and high crosslinking density during epoxy resin curing, resulting in extremely low water absorption and excellent moisture resistance after curing; simultaneously, the carbon fiber and aramid fiber surfaces have no hydrogen bonds, thus they do not absorb water. The present invention, through the design and mutual compounding of epoxy resin, curing agent, carbon fiber, and aramid fiber, enables the composite cone to possess extremely low water absorption and excellent moisture resistance, thereby expanding the application of speaker products incorporating it in outdoor, underwater, marine, and jet ski fields.

[0054] Preferably, the solvent includes any one or a combination of at least two of ester solvents, ketone solvents, and aromatic solvents.

[0055] Preferably, the ester solvent includes ethyl acetate and / or butyl acetate.

[0056] Preferably, the ketone solvent includes any one or a combination of at least two of acetone, butanone, cyclohexanone, and methyl isobutyl ketone.

[0057] Preferably, the aromatic solvent includes any one or a combination of at least two of toluene, xylene, and trimethylbenzene.

[0058] Preferably, the solvent includes any one or a combination of at least two of ethyl acetate, acetone, butanone, and cyclohexanone, with cyclohexanone being more preferred.

[0059] Preferably, the mass ratio of epoxy resin to solvent is 1:(2.5-6.5), for example, it can be 1:2.6, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.2 or 1:6.4, etc.

[0060] As a preferred embodiment of the present invention, the mass ratio of epoxy resin, curing agent, and solvent in the epoxy adhesive is 1:(0.2-0.5):(2.5-6.5), thereby giving the epoxy adhesive a suitable epoxy resin concentration and viscosity. After the first cone blank is fully impregnated in it, the epoxy adhesive (epoxy resin + curing agent) can penetrate into and remain inside the first cone blank, adhering to the interlacing sites of carbon fibers and aramid fibers in the cone, providing excellent bonding performance. If the amount of solvent is too small, the viscosity of the epoxy adhesive is too large, and its penetration effect in the first cone blank is weakened, thus the Young's modulus of the resulting composite cone is relatively small; and the epoxy resin is enriched on the surface of the cone, resulting in a relatively large density of the composite cone. If the amount of solvent is too large, the amount of epoxy resin and curing agent retained in the first cone blank is small, weakening the bonding force between carbon fibers and aramid fibers, thus the Young's modulus of the resulting composite cone is relatively small and the strength is insufficient.

[0061] Preferably, when the aramid fiber is dispersed in water for pulping, the mass ratio of the aramid fiber to water is 1:(230-300), for example, it can be 1:235, 1:240, 1:245, 1:250, 1:255, 1:260, 1:265, 1:270, 1:275, 1:280, 1:285, 1:290 or 1:295, etc.

[0062] Preferably, the aramid fibers are pulped using a trough pulper.

[0063] Preferably, during the pulping process of the aramid fiber dispersed in water, the gap between the flying knife and the bottom knife is 0.1-0.3 mm, for example, it can be 0.12 mm, 0.15 mm, 0.18 mm, 0.2 mm, 0.22 mm, 0.25 mm or 0.28 mm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0064] Preferably, the pulping time is 4-10 hours, for example, it can be 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours or 9.5 hours, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0065] Preferably, the degree of solubility of component A is 15-40°SR, for example, it can be 16°SR, 18°SR, 20°SR, 22°SR, 25°SR, 28°SR, 30°SR, 32°SR, 35°SR or 38°SR, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0066] As a preferred technical solution of the present invention, a specific pulping process is used to pulp aramid fibers. By controlling the mass ratio of aramid fibers to water to be 1:(230-300) and controlling the gap between the fly knife and the bottom knife to be 0.1-0.3mm, the fly knife and the bottom knife do not have a shearing effect on the aramid fibers during the pulping process. Relying on the mutual friction between the aramid fibers, the highly oriented skin layer of the aramid fibers is detached, and the microfibers of the core layer are extracted, forming a fluffy filament that coils around the main shaft. This results in a large number of fluffy microfibers being split on the surface of the aramid fibers, maximizing the degree of aramid fiber splitting and bristling, and obtaining component A with a beating degree (sizing degree) of 15-40°SR. At this time, the average length of the aramid fibers in component A is 5.5-6.5mm. The aramid fibers maintain a relatively long length, and the degree of filament splitting and bristling is significantly improved, thereby increasing the interlacing points and bonding force of the aramid fibers and carbon fibers, making them suitable as winding fibers to improve the strength of the composite cone.

[0067] Preferably, the mixed materials also include water and a dispersant.

[0068] Preferably, the dispersant comprises polyethylene glycol.

[0069] Preferably, the mass of the dispersant is 50-120% based on the total mass of the aramid fiber (octane weight of component A) and carbon fiber as 100%, for example, it can be 60%, 70%, 80%, 90%, 100%, 110% or 115%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0070] As a preferred technical solution of the present invention, when preparing component B, component A (aramid pulp) and carbon fiber are dispersed in water, polyethylene glycol is added to improve the dispersibility of aramid fiber and carbon fiber, and the mixture is stirred evenly so that the carbon fiber is wrapped and wound by the aramid fiber in component A that has been pulped, thereby constructing a cone structure with carbon fiber as the supporting fiber and aramid fiber as the winding fiber.

[0071] Preferably, the method for preparing the wet cone embryo specifically includes: diluting group B with water and filtering it to obtain the wet cone embryo.

[0072] Preferably, the temperature of the first hot pressing is 150-200℃, for example, it can be 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃ or 195℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0073] Preferably, the first hot pressing time is 20-45s, for example, it can be 22s, 25s, 28s, 30s, 32s, 35s, 38s, 40s, 42s or 44s, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0074] As a preferred embodiment of the present invention, the first hot pressing does not require additional pressure; the wet cone blank is dehydrated and shaped by the weight of the upper mold of the hot pressing mold itself. After the first hot pressing completes the drying process, the density of the first cone blank is 0.4-0.55 g / cm³. 3 Within this range, the inter-fiber pores of the first cone blank are relatively large, and the structure is loose, similar to the structure of a "bird's nest". This loose structure helps the epoxy resin to penetrate and remain in the first cone blank, and then adhere to the interlacing sites of the carbon fiber and aramid fiber.

[0075] Preferably, the density of the first cone blank is 0.4-0.55 g / cm³. 3 For example, it can be 0.42 g / cm³. 3 0.45g / cm 3 0.48g / cm 3 0.5g / cm 3 0.52g / cm 3 Or 0.54g / cm 3 As well as the specific point values ​​between the above point values, due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0076] Preferably, the temperature of the second hot pressing is 150-200℃, for example, it can be 155℃, 160℃, 165℃, 170℃, 175℃, 180℃, 185℃, 190℃ or 195℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0077] Preferably, the pressure of the second hot pressing is 0.2-0.6 MPa, for example, it can be 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.38 MPa, 0.4 MPa, 0.45 MPa, 0.5 MPa or 0.55 MPa, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0078] Preferably, the second hot pressing time is 60-90s, for example, it can be 62s, 65s, 68s, 70s, 72s, 75s, 78s, 80s, 82s, 85s or 88s, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0079] As a preferred embodiment of the present invention, the second hot pressing requires pressurization, with a pressure of 0.2-0.6 MPa. Increasing the pressure during the second hot pressing allows the carbon fibers and aramid fibers to bond tightly, reducing the porosity of the cone and improving its rigidity. During this process, the epoxy resin cures under heat, acting as a bond between the carbon fibers and aramid fibers, and the cured epoxy adhesive also increases in strength, further enhancing the strength of the composite cone.

[0080] Preferably, after the second hot pressing is completed, a punching step is further included to remove excess central holes and edge material.

[0081] Preferably, the raw materials in the preparation method include, by weight:

[0082]

[0083]

[0084] The preparation method specifically includes the following steps:

[0085] Aramid fibers are dispersed in water and pulped, wherein the mass ratio of aramid fibers to water is 1:(230-300), the gap between the flying knife and the bottom knife is 0.1-0.3 mm, and pulping is carried out for 4-10 hours to obtain component A with a freeness of 15-40°SR.

[0086] Component A and carbon fiber were dispersed in water, and polyethylene glycol was added as a dispersant. The dispersion was uniform to obtain component B.

[0087] An epoxy adhesive solution is provided, the epoxy adhesive solution comprising epoxy resin, curing agent and solvent in a mass ratio of 1:(0.2-0.5):(2.5-6.5);

[0088] Component B was diluted with water and then filtered to obtain a wet soundbox embryo.

[0089] The wet cone blank is subjected to a first hot pressing at 150-200℃ to obtain a density of 0.4-0.55 g / cm³. 3 The first cone blank;

[0090] The first cone blank is fully immersed in epoxy resin and then left to dry to obtain the second cone blank.

[0091] The second cone blank is subjected to a second hot pressing at a temperature of 150-200℃ and a pressure of 0.2-0.6MPa, and then punched to obtain the composite cone.

[0092] In a second aspect, the present invention provides a composite cone, which is prepared by the preparation method described in the first aspect.

[0093] Preferably, the density of the composite cone is 0.75-0.95 g / cm³. 3 Further optimization was performed using 0.81-0.88 g / cm³. 3 .

[0094] Preferably, the Young's modulus of the composite cone is ≥8 GPa, more preferably ≥8.4 GPa, and even more preferably ≥8.9 GPa, which can be 8.94-9.76 GPa.

[0095] Preferably, the water absorption rate of the composite cone is ≤0.6%, more preferably ≤0.45%, and even more preferably ≤0.25%, and can be 0.19-0.23%.

[0096] Thirdly, the present invention provides a loudspeaker comprising a composite cone as described in the second aspect.

[0097] Compared with the prior art, the present invention has the following beneficial effects:

[0098] (1) In the method for preparing the composite cone provided by the present invention, the design and synergistic effect of carbon fiber, aramid fiber and epoxy resin, combined with a specific preparation process, effectively utilizes the advantages of high strength and high modulus of carbon fiber and aramid fiber. Based on the synergy of epoxy resin and specific process, the carbon fiber and aramid fiber form excellent interweaving force and high adhesion force, so that the composite cone has high strength and excellent waterproof and moisture-proof performance.

[0099] (2) The preparation method provided by the present invention can prepare composite cones with high taper and complex shape. When the composite cone is applied to loudspeakers, it can expand the frequency response range of loudspeakers, improve the weather resistance of loudspeakers, expand the application of loudspeaker products in outdoor, underwater, ship, jet ski and other fields, and greatly enrich the application range of loudspeakers.

[0100] (3) Through the design of components and optimization of the preparation process, the present invention enables the composite cone to have a Young's modulus ≥ 8.9 GPa and a density of 0.81-0.88 g / cm³. 3With a water absorption rate of ≤0.25% and a waterproof rating of IPX7, it combines high strength, high modulus, low density, low water absorption and moisture absorption rate, high weather resistance and stability, enabling loudspeakers containing it to have higher high-frequency cutoff frequencies and to be used in more severe humid environments. Detailed Implementation

[0101] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0102] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not limited to those elements and may also include other elements not expressly listed or elements inherent to such composition, step, method, article, or apparatus.

[0103] In this invention, features defined with "first," "second," and "third" may explicitly or implicitly include one or more of those features, used to distinguish and describe features, without any order or emphasis. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0104] The specific information of the materials used in the following specific embodiments of the present invention is as follows:

[0105] (1) Aramid fiber: Para-aramid fiber with an average length of 6mm, purchased from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0106] (2) Carbon fiber: Short-cut carbon fiber with an average length of 6mm, purchased from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0107] (3) Polyethylene glycol: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0108] (4) Epoxy resin: Epoxy laminated resin, EL2, purchased from Composite Easy Buy (Beijing) Technology Co., Ltd.

[0109] (5) Curing agent: AY30 FAST, purchased from Composite Easy Buy (Beijing) Technology Co., Ltd.

[0110] (6) Solvent: Cyclohexanone, purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0111] Example 1

[0112] A composite cone and its preparation method, wherein the raw materials for preparation include, by weight:

[0113]

[0114] The specific preparation method is as follows:

[0115] (1) Aramid fibers were dispersed in water at a mass ratio of aramid fibers to water of 1:280. The mixture was pulped using a trough pulper with a gap of 0.2 mm between the fly knife and the bottom knife. After pulping for 8 hours, component A with a freeness of 30°SR was obtained.

[0116] Component A and carbon fiber are dispersed in water, and polyethylene glycol (based on the total dry weight of component A and the total mass of carbon fiber being 100%, the amount of polyethylene glycol added is 100%) is added as a dispersant. The mixture is stirred and dispersed evenly to obtain component B.

[0117] Epoxy resin, curing agent and cyclohexanone are mixed in a mass ratio of 5:1.5:26 and stirred evenly to obtain epoxy adhesive solution;

[0118] (2) Dilute component B obtained in step (1) with water, filter, and obtain wet diaphragm embryo;

[0119] (3) The wet cone blank obtained in step (2) is placed in a high-temperature mold for hot pressing and drying. The hot pressing temperature is 185℃, without additional hot pressing pressure. After pressing and drying for 35s, the first cone blank is obtained.

[0120] (4) The first cone blank obtained in step (3) is immersed in epoxy resin to make it completely wetted, and then left to dry to obtain the second cone blank.

[0121] (5) Transfer the second cone blank obtained in step (4) to a hot press mold for a second hot pressing and shaping. The hot pressing pressure is 0.5MPa and the time is 75s. Then punch off the excess central hole and edge material to obtain the composite cone.

[0122] Examples 2-10, Comparative Examples 1-4

[0123] A composite cone and its preparation method differ from Example 1 in that at least one of the following is different: the amount of raw materials used, the degree of percussion of component A, and the pressure of the second hot pressing, as shown in Table 1. In Table 1, the amount of raw materials used is in "parts", and "--" indicates that the component was not added; the processes and parameters not shown in Table 1 are the same as in Example 1.

[0124] Table 1

[0125]

[0126] Comparative Example 5

[0127] A composite cone and its preparation method are disclosed. The only difference between this invention and Example 1 is that carbon fiber is replaced with glass fiber of equal mass. All other components, dosages, and preparation methods are the same as in Example 1.

[0128] Comparative Example 6

[0129] A composite cone and its preparation method are disclosed, differing from Example 1 only in that the aramid fibers are not pulped; instead, the aramid fibers and carbon fibers are directly mixed according to the formula, diluted with water, and filtered to obtain a wet cone blank. The components and other preparation steps are the same as in Example 1.

[0130] Comparative Example 7

[0131] A composite cone and its preparation method are disclosed. The only difference between this and Example 1 is that the epoxy resin is replaced with an equal mass of phenolic resin (brand name 803L, purchased from Guangzhou Qianyiyuan Synthetic Materials Technology Co., Ltd.), and no curing agent is required. The other components, dosages, and preparation methods are the same as in Example 1.

[0132] The performance of the composite cones provided in Examples 1-10 and Comparative Examples 1-7 was tested using the following methods:

[0133] (1) Density: The mass / volume method was used. The mass of the composite cone was measured by an electronic balance, the thickness of the composite cone was measured by a micrometer, and the volume of the composite cone was calculated by a 3D model of the composite cone.

[0134] (2) Young's modulus: The Young's modulus of the composite cone was tested using the Material Parameter Testing Module (MPM) in KLIPPEL R&D SYSTEM to characterize its strength;

[0135] (3) Moisture-proof performance: expressed as water absorption rate. The lower the water absorption rate, the better the moisture-proof performance. The specific test method is as follows: place the composite cone in an environment with a temperature of 25℃ and a humidity of 85% for 14 days, and record the percentage increase in weight of the composite cone before and after storage, which is the water absorption rate;

[0136] (4) Waterproof performance:

[0137] IPX5 level test standard: water spray test; test equipment: nozzle inner diameter of water outlet is 6.3mm; test conditions: the distance between the sample to be tested and the water outlet is 2.5-3m, the water flow rate is 12.5L / min; test time: calculated based on the surface area of ​​the sample shell, 1min per square meter (excluding the installation area), the total test time shall not be less than 3min.

[0138] IPX6 level test standard: strong water spray test; test equipment: nozzle nozzle inner diameter is 12.5mm; test conditions: the distance between the sample to be tested and the nozzle is 2.5-3m, the water flow rate is 100L / min; test time: calculated based on the surface area of ​​the sample shell, 1min per square meter (excluding the installation area), the total test time shall not be less than 3min.

[0139] IPX7 level test standard: short-term immersion test; test equipment and test conditions: immersion tank, the size of which should be such that after the sample is placed in the immersion tank, the distance from the bottom of the sample to the water surface is at least 1m, and the distance from the top of the sample to the water surface is at least 0.15m; test time: 30min.

[0140] The test results are shown in Table 2:

[0141] Table 2

[0142]

[0143]

[0144] As shown in Table 2, the test data of this invention utilizes specific amounts of carbon fiber, aramid fiber, and epoxy resin for compounding. Each component, in specific amounts, synergistically enhances and complements the others' properties, and works in conjunction with a specific preparation method. This results in the composite cones provided in Examples 1-4 having a Young's modulus of 8.94-9.76 GPa and a density of 0.81-0.88 g / cm³. 3 With a water absorption rate of 0.19%-0.23% and a waterproof rating of IPX7, it combines high strength, high modulus, low density, and good weather resistance, enabling loudspeakers containing it to have higher high-frequency cutoff frequencies and to be used in more demanding humid environments.

[0145] In the preparation method of this invention, by controlling the ratio of epoxy resin, curing agent, and solvent, the epoxy adhesive solution has a suitable epoxy resin concentration and viscosity. After the loosely structured first cone blank is fully impregnated in it, the epoxy adhesive can penetrate into and remain inside the first cone blank, adhering to the interlacing sites of carbon fibers and aramid fibers in the cone, providing excellent bonding performance. In Example 5, the epoxy resin concentration is too low, resulting in less epoxy resin retention in the composite cone, weakening the bonding force between carbon fibers and aramid fibers, thus the Young's modulus of the resulting composite cone is relatively small. In Example 6, the epoxy resin concentration is too high, and the viscosity of the epoxy adhesive solution is also too high, resulting in weakened penetration of the adhesive solution in the first cone blank, thus the Young's modulus of the resulting composite cone is relatively small; at the same time, the epoxy resin will accumulate on the surface of the composite cone, resulting in a higher density of the composite cone.

[0146] In this invention, the carbon fiber, aramid fiber, and epoxy resin are used in specific amounts to synergistically enhance each other and complement each other's properties. This not only effectively leverages the advantages of high strength and high modulus of carbon fiber and aramid fiber, but also improves the bonding and adhesion between carbon fiber and aramid fiber.

[0147] In Example 7, the amount of epoxy resin added was too high, resulting in a higher density of the composite cone.

[0148] In Example 8, the amount of epoxy resin added was too low, resulting in less epoxy resin remaining in the composite cone. This weakened the bonding force between the carbon fiber and the aramid fiber, thus the composite cone had a lower Young's modulus and higher water absorption, resulting in lower moisture resistance.

[0149] In Example 9, the amount of carbon fiber used was relatively small, resulting in fewer rigid fibers that provide support in the composite cone, thus reducing the Young's modulus of the composite cone.

[0150] In Example 10, the proportion of carbon fiber is relatively large, which weakens the interweaving force between the two types of fibers, resulting in a loose composite cone structure with high porosity. Consequently, the composite cone strength decreases, the water absorption rate increases, and the waterproof performance decreases.

[0151] As can be seen from the comparison between Example 1 and Comparative Examples 1-3, when no carbon fiber is added to the composite cone, there are no rigid fibers in the cone to provide support, thus the Young's modulus of the composite cone decreases. When no aramid fiber is added to the composite cone, there are no fibers in the cone to provide interweaving and winding, and the cone cannot be formed. When the first cone blank is formed, it is not impregnated with epoxy resin. At this time, the fibers in the composite cone only have interweaving force and no bonding force, resulting in a loose composite cone structure that cannot be tested.

[0152] As can be seen from the comparison between Example 1 and Comparative Example 4, when no pressure is applied during the second hot pressing process in the preparation of the composite cone, the resulting composite cone has a loose structure and high porosity, which leads to a decrease in the strength of the composite cone, an increase in water absorption, and a decrease in water resistance.

[0153] As can be seen from the comparison between Example 1 and Comparative Example 5, if glass fiber of the same mass is used to replace carbon fiber, the Young's modulus and strength of the composite cone will decrease and the density will increase because the strength of glass fiber is less than that of carbon fiber and the specific gravity is greater than that of carbon fiber.

[0154] As can be seen from the comparison between Example 1 and Comparative Example 6, if the aramid fiber is added directly without pulping, there is no interweaving force between the two fibers, and the composite cone cannot be formed.

[0155] As can be seen from the comparison between Example 1 and Comparative Example 7, if phenolic resin is used to replace epoxy resin of equal mass, the density of the prepared composite cone is larger and the water absorption rate also increases.

[0156] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate the composite cone, its preparation method, and its application. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, and selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a composite cone, characterized in that, The preparation method includes: Aramid fibers were dispersed in water and pulped to obtain component A; Component A is mixed evenly with carbon fiber to obtain component B; An epoxy adhesive solution is provided, the epoxy adhesive solution comprising a combination of epoxy resin, curing agent and solvent; Component B is filtered to obtain a wet soundboard embryo; The wet cone blank is subjected to a first hot pressing to obtain a first cone blank; The first cone blank is immersed in epoxy resin and then dried to obtain the second cone blank. The second cone blank is subjected to a second hot pressing to obtain the composite cone.

2. The preparation method according to claim 1, characterized in that, The raw materials used in the preparation method include, by mass parts: 85-95 parts of aramid fiber 5-15 parts carbon fiber 3-5 parts epoxy resin 0.6-2.5 parts of curing agent.

3. The preparation method according to claim 1, characterized in that, The average length of the aramid fiber is 5.5-6.5 mm.

4. The preparation method according to claim 1, characterized in that, The average length of the carbon fiber is 4-7 mm.

5. The preparation method according to claim 1, characterized in that, The epoxy resin includes epoxy laminated resin.

6. The preparation method according to claim 1, characterized in that, The curing agent includes amine curing agents and / or phenolic curing agents.

7. The preparation method according to claim 1, characterized in that, The mass ratio of epoxy resin to curing agent is 1:(0.2-0.5).

8. The preparation method according to claim 1, characterized in that, The solvent includes any one or a combination of at least two of the following: ester solvents, ketone solvents, and aromatic solvents.

9. The preparation method according to claim 1, characterized in that, The solvent includes any one or a combination of at least two of ethyl acetate, acetone, butanone, and cyclohexanone.

10. The preparation method according to claim 1, characterized in that, The mass ratio of the epoxy resin to the solvent is 1:(2.5-6.5).

11. The preparation method according to claim 1, characterized in that, The mass ratio of the aramid fiber to water is 1:(230-300).

12. The preparation method according to claim 1, characterized in that, During the pulping process of the aramid fibers dispersed in water, the gap between the flying knife and the bottom knife is 0.1-0.3 mm.

13. The preparation method according to claim 1, characterized in that, The pulping time is 4-10 hours.

14. The preparation method according to claim 1, characterized in that, The degree of solubility of component A is 15-40°SR.

15. The preparation method according to claim 1, characterized in that, The mixture also includes water and a dispersant.

16. The preparation method according to claim 15, characterized in that, The dispersant includes polyethylene glycol.

17. The preparation method according to claim 15, characterized in that, With the total mass of the aramid fiber and carbon fiber being 100%, the mass of the dispersant is 50-120%.

18. The preparation method according to claim 1, characterized in that, The specific method for preparing the wet cone embryo includes: diluting component B with water and filtering it to obtain the wet cone embryo.

19. The preparation method according to claim 1, characterized in that, The temperature of the first hot press is 150-200℃.

20. The preparation method according to claim 1, characterized in that, The density of the first cone blank is 0.4-0.55 g / cm 3 .

21. The preparation method according to claim 1, characterized in that, The temperature of the second hot pressing is 150-200℃.

22. The preparation method according to claim 1, characterized in that, The pressure of the second hot press is 0.2-0.6 MPa.

23. The preparation method according to claim 1, characterized in that, The second hot pressing process also includes a punching step.

24. A composite cone, characterized in that, The composite cone is prepared by the preparation method according to any one of claims 1-23.

25. The composite cone according to claim 24, characterized in that, The density of the composite sound basin is 0.75-0.95 g / cm 3 .

26. The composite cone according to claim 25, characterized in that, The density of the composite sound basin is 0.81-0.88 g / cm 3 .

27. The composite cone according to claim 24, characterized in that, The Young's modulus of the composite cone is ≥8 GPa.

28. The composite cone according to claim 27, characterized in that, The Young's modulus of the composite cone is ≥8.9 GPa.

29. The composite cone according to claim 24, characterized in that, The water absorption rate of the composite cone is ≤0.6%.

30. The composite cone according to claim 29, characterized in that, The water absorption rate of the composite cone is ≤0.25%.

31. A loudspeaker, characterized in that, The loudspeaker includes a composite cone as described in any one of claims 24-30.

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