A loudspeaker cone, its preparation method and application

Abstract

This invention provides a loudspeaker cone, its preparation method, and its application. The raw materials for preparing the loudspeaker cone, by weight, include the following components: 20-70 parts bleached sulfate wood pulp, 5-40 parts bark pulp, 5-40 parts hemp pulp, 2-50 parts bamboo fiber, and 0.1-3 parts chitosan. Through the specific amounts of bleached sulfate wood pulp, bark pulp, hemp pulp, bamboo fiber, and chitosan working together, the different properties of the fibers synergistically and / or complement each other, and the components synergistically enhance each other, effectively improving the strength of the cone and reducing its density. This results in a high Young's modulus and low density for the loudspeaker cone, thereby widening the frequency response range and improving the speaker's sensitivity. Simultaneously, the loudspeaker cone has appropriate internal damping, which can suppress cone breakage vibration, making the speaker's frequency response characteristics flatter and improving the low-frequency sound quality.

Description

Technical Field

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

[0002] The working principle of a loudspeaker is that when an alternating audio current is passed through the voice coil, which is connected to the cone and centering support, the voice coil vibrates under the influence of electromagnetic force in the magnetic field. This vibration drives the cone to vibrate the air, producing sound. The characteristics of the cone directly affect the loudspeaker's electroacoustic parameters, sound quality, and lifespan, making it a key component of the vibration system.

[0003] To improve the acoustic performance of loudspeakers, the industry has conducted numerous studies on paper cone formulations and processes. For example, CN111279722A discloses a method for manufacturing paper cones to improve loudspeaker sound performance. The specific steps are as follows: unbleached sulfate pulp, rice straw, and carbon fiber are pulped to obtain a first pulp, with a formulation ratio of 70% unbleached sulfate pulp, 15% rice straw, and 15% carbon fiber; the first pulp, adhesive, precipitant, and dye are mixed using a stirring device to obtain a second pulp; the second pulp is subjected to a shaping process to obtain a paper cone blank; the paper cone blank is then passed sequentially through an automatic or semi-automatic hot press, an automatic temperature control device, and a paper cone hot pressing die to obtain a hot-pressed paper cone, which is then post-treated to obtain a high-performance composite paper cone, thereby improving the loudspeaker's sound performance. CN109968737A discloses a paper cone formula for improving the sound performance of a loudspeaker, which is composed of the following components by weight: 1%-50% unbleached sulfate pulp, 30%-50% bleached sulfite pulp, and 1%-20% bulletproof cloth; the paper cone and loudspeaker obtained by this formula have high sound layering and reproduction capabilities. CN113846513A discloses a graphene paper cone formulation comprising the following raw materials in parts by weight: 30-40% EKB pulp board, 50-58% Northwood pulp board, 2-5% kapok fiber, 8-12% Direct Black Red Light 3BG dye, 8-10% aluminum sulfate, 8-12% industrial salt, 0.2-1% graphene, 40-50% polypropylene raw material, 1-1.5% lubricant, 4.5-3% maleic anhydride, and 1-0.5% white oil. This formulation, by adding graphene, can improve the rigidity of the paper cone without increasing its weight, and has the effects of improving low, mid, and high frequency sound quality, increasing power, and raising sound pressure level.

[0004] Studies have shown that paper cone materials should meet the following requirements: (1) The material density ρ should be low. Reducing the density of the paper cone can reduce the vibrating mass of the loudspeaker, thereby improving the sensitivity of the loudspeaker; (2) The material should have a large Young's modulus. Increasing the Young's modulus of the paper cone can reduce the unit's split vibration and phase distortion, thereby improving the frequency response range of the loudspeaker; (3) It should have appropriate internal damping, which can suppress the split vibration of the paper cone and make the frequency response characteristics relatively flat. Although the existing technology discloses the formulation and manufacturing process of the paper cone, it is difficult to achieve good results in terms of low density, high modulus and appropriate internal damping, resulting in poor overall performance of the paper cone and difficulty in meeting the performance requirements of high-performance loudspeakers.

[0005] Therefore, developing paper cone materials with low density, high Young's modulus, appropriate internal damping, and excellent overall performance is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a loudspeaker cone, its preparation method, and its application. By designing and compounding bleached sulfate wood pulp, bark pulp, hemp pulp, bamboo fiber, and chitosan, the loudspeaker cone achieves a high Young's modulus, low density, and moderate internal damping. When applied to loudspeaker products, it can broaden the frequency response range of the loudspeaker and improve its sensitivity.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a speaker cone, wherein the raw materials for preparing the speaker cone comprise the following components in parts by weight:

[0009]

[0010]

[0011] This invention uses specific amounts of bleached sulfate wood pulp, bark pulp, hemp pulp, bamboo fiber, and chitosan as raw materials for preparing speaker cones, wherein: (1) The bleached sulfate wood pulp (BKP) is a coarse and long fiber with small cell cavities and thick cell walls, that is, a large fiber cell wall-cavity ratio, hard fibers, and high rigidity. The thick-walled fibers have a significant impact on wet compressibility and can retain more of their original tubular form during extrusion drying. (2) The bark pulp has a good fiber morphology, and its long fibers give it high tear strength when made into paper, creating favorable conditions for improving the strength of the cone. (3) The hemp pulp has no gel coat on the fiber outer wall, thick cell walls, extremely small cell cavities, very small voids, polygonal fibers, and is tough and elastic, which helps to improve the strength of the cone. (4) The bamboo fiber retains the natural physical properties of bamboo. The fiber contains a large number of hollow structures and cell cavities, which helps to reduce the density of the cone and improve the timbre and sound quality of the speaker. (5) Chitosan and cellulose have similar structures and have a significant affinity for plant fibers. As a raw material, chitosan is adsorbed by plant fibers and fills the spaces between fibers. This filling effect increases the bonding between fibers and helps improve the strength of the paper cone. At the same time, the active groups on the surface of chitosan will form hydrogen bonds with the hydroxyl groups on the surface of cellulose, further improving the strength of the paper cone.

[0012] Specifically, the speaker cone of this invention incorporates bamboo fiber, which is obtained by physical and mechanical methods through material preparation, sheeting, filament separation, combing, and screening. It consists of naturally obtained bundled, filamentous, or flocculent bamboo fiber units, comprising single bamboo fiber cells or aggregates of multiple fiber cells, effectively preserving the natural physical and biochemical properties of bamboo. The bamboo fiber possesses a type I cellulose crystalline structure with good thermal stability, high crystallinity, tightly packed macromolecules, and intact molecular structure. Its cavity structure is also relatively well preserved. It has transverse nodes along its longitudinal direction, and micro-grooves distributed on the fiber surface. Laterally, it exhibits irregular elliptical or kidney-shaped forms, possessing advantages such as low density, light weight, and high strength and rigidity. This results in excellent effects on reducing cone density, increasing strength, and improving sound quality / timbre and overall listening experience.

[0013] Therefore, this invention uses bleached sulfate wood pulp (BKP), bark pulp, hemp pulp, and bamboo fiber in specific proportions to create a compound. The fibers with different properties work synergistically and / or complement each other, and are compounded with chitosan. The components work synergistically to increase the strength and Young's modulus of the speaker cone, while reducing its density. This widens the frequency response range of the speaker and improves its sensitivity. At the same time, the speaker cone has moderate internal damping, which can suppress the cone's splitting vibration, making the speaker's frequency response characteristics flatter and improving the low-frequency sound quality of the speaker.

[0014] In the raw materials for preparing the speaker cone provided by the present invention, the bleached sulfate wood pulp has a mass fraction of 20-70 parts, for example, 25 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts, 48 ​​parts, 50 parts, 52 parts, 55 parts, 58 parts, 60 parts, or 65 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.

[0015] The bark pulp is in the range of 5-40 parts by weight, for example, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts or 38 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.

[0016] The mass fraction of the hemp pulp is 5-40 parts, for example, it can be 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts or 38 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.

[0017] The mass fraction of the bamboo fiber is 2-50 parts, for example, it can be 5 parts, 8 parts, 10 parts, 12 parts, 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 28 parts, 30 parts, 32 parts, 35 parts, 38 parts, 40 parts, 42 parts, 45 parts or 48 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.

[0018] The chitosan is present in a mass fraction of 0.1-3 parts, for example, 0.2 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.1 parts, 1.3 parts, 1.5 parts, 1.7 parts, 1.9 parts, 2 parts, 2.2 parts, 2.5 parts, or 2.8 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 all the specific values ​​included in the range.

[0019] 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.

[0020] Preferably, the raw materials for preparing the speaker cone include the following components in parts by weight:

[0021]

[0022] Preferably, the fiber length distribution of the bleached sulfate wood pulp (BKP) is 0.3-4.11 mm, for example, it can be 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm or 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.

[0023] Preferably, the average fiber length of the bleached sulfate wood pulp (BKP) is 2-3 mm, for example, it can be 2.1 mm, 2.2 mm, 2.3 mm, 2.4 mm, 2.5 mm, 2.6 mm, 2.7 mm, 2.8 mm or 2.9 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.

[0024] Preferably, the fiber fibrillation rate of the bleached sulfate wood pulp (BKP) is 2-2.5%, for example, it can be 2.05%, 2.1%, 2.15%, 2.2%, 2.25%, 2.3%, 2.35%, 2.4% or 2.45%, 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.

[0025] In a preferred embodiment, the bleached sulfate wood pulp (BKP) has an average fiber length of 2.48 mm and a fiber fibrillation rate of 2.207%.

[0026] Preferably, the bark pulp is "paper mulberry bark pulp", which is pulp obtained by alkaline pulping using paper mulberry bark as raw material; the fiber morphology of paper mulberry bark is relatively good, and its long fibers give the paper high tear strength, which helps to improve the strength and modulus of the paper.

[0027] Preferably, the fiber length distribution of the bark pulp is 0.43-6 mm, for example, it can be 0.5 mm, 0.8 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm, 3.8 mm, 4 mm, 4.2 mm, 4.5 mm, 4.8 mm, 5 mm or 5.5 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.

[0028] Preferably, the average fiber length of the bark pulp is 2.5-4 mm, for example, it can be 2.6 mm, 2.8 mm, 3 mm, 3.2 mm, 3.5 mm or 3.8 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.

[0029] Preferably, the fiber fibrillation rate of the bark pulp is 3.2-3.8%, for example, it can be 3.25%, 3.3%, 3.35%, 3.4%, 3.45%, 3.5%, 3.55%, 3.6%, 3.65%, 3.7% or 3.75%, 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.

[0030] In a preferred embodiment, the average fiber length of the bark pulp is 3.16 mm, and the fiber fibrillation rate is 3.544%.

[0031] Preferably, the average fiber length of the hemp pulp is 10-30mm, for example, it can be 16mm, 18mm, 20mm, 22mm, 25mm or 28mm, 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 15-20mm is further preferred.

[0032] Preferably, the aspect ratio of the hemp pulp fibers is 800-1300, for example, it can be 850, 900, 950, 1000, 1050, 1100, 1150, 1200 or 1250, 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 average length of the bamboo fiber is 15-50mm, for example, it can be 16mm, 18mm, 20mm, 22mm, 25mm, 28mm, 30mm, 32mm, 35mm, 38mm, 40mm, 42mm or 48mm, 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.

[0034] Preferably, the ultra-long fiber rate (mass percentage of fibers ≥90mm) of the bamboo raw fiber is 1%-15%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 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.

[0035] Preferably, the short fiber rate (mass percentage of fibers <15mm) of the bamboo raw fiber is 1%-15%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 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.

[0036] Preferably, the linear density of the bamboo fiber is ≤2.5tex, for example, it can be 0.5tex, 0.8tex, 1tex, 1.2tex, 1.5tex, 1.8tex, 2tex, 2.2tex or 2.4tex, 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 breaking strength of the bamboo fiber is ≥2Cn / dtex, for example, it can be 2.2Cn / dtex, 2.3Cn / dtex, 2.5Cn / dtex, 2.7Cn / dtex, 2.8Cn / dtex or 3Cn / dtex, 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, but 2-3Cn / dtex is further preferred.

[0038] Preferably, the moisture content of the bamboo fiber is ≤10%, for example, it can be 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9% or 9.5%, 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, but 5%-10% is further preferred.

[0039] As a preferred embodiment of the present invention, the bamboo fiber has a uniform color, is free of metallic foreign matter and foreign fibers, and possesses a cellulose type I crystalline structure. It exhibits good thermal stability, high crystallinity, and tightly packed macromolecules, significantly different from the cellulose type II crystalline structure of conventional bamboo pulp or bamboo fiber (the molecular structure of bamboo pulp or bamboo fiber is destroyed during the pulping process, resulting in low crystallinity and a sparsely packed cellulose type II crystalline structure). Simultaneously, the bamboo fiber possesses high breaking strength, low moisture content, and suitable fiber length, while retaining a relatively intact internal cavity structure. These specific crystal structure, fiber structure, and properties give the bamboo fiber a more significant advantage in reducing the density of the cone and improving its sound quality and listening experience.

[0040] Preferably, the viscosity of the chitosan is <200 mPa·s, for example, it can be 80 mPa·s, 100 mPa·s, 120 mPa·s, 150 mPa·s or 180 mPa·s, as well as 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.

[0041] Preferably, the degree of deacetylation of the chitosan is ≥95%.

[0042] Preferably, the raw materials used in the preparation also include acidic compounds.

[0043] Preferably, the acidic compound includes any one or a combination of at least two of formic acid, acetic acid, hydrochloric acid, and lactic acid.

[0044] Preferably, the mass ratio of the acidic compound to chitosan is (0.1-2):1, for example, it can be 0.2:1, 0.3:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1 or 1.8:1, etc.

[0045] In a second aspect, the present invention provides a method for preparing a loudspeaker cone as described in the first aspect, the method comprising:

[0046] Bleached sulfate wood pulp, bark pulp, and hemp pulp were mixed and pulped to obtain component A; bamboo fiber was pulped to obtain component B.

[0047] Component A and component B are mixed to obtain a fiber suspension;

[0048] The fiber suspension was mixed evenly with the chitosan aqueous solution and then filtered to obtain a wet paper basin preform.

[0049] The wet paper basin blank is hot-pressed to obtain a paper basin blank;

[0050] The paper cone blank is punched to obtain the speaker cone.

[0051] Because bamboo fibers have longitudinal knots and uneven distribution in length and thickness, they tend to agglomerate when directly used to prepare speaker cones, resulting in uneven distribution and unstable performance. The speaker cone preparation method provided by this invention involves separately pulping the bamboo fibers. The average length and dispersion of the bamboo fibers in component B meet the requirements for high-performance speaker cones, significantly improving their performance and stability. Furthermore, the pulping process in component B enhances the fibrillation of the bamboo fibers, strengthens their bonding with bleached sulfate wood pulp, bark pulp, and hemp pulp, and improves their interaction with chitosan, further enhancing the strength and overall performance of the speaker cone.

[0052] Preferably, the pulp consistency of the bleached sulfate wood pulp, bark pulp, and hemp pulp mixture is 1.1%-1.8%, for example, it can be 1.15%, 1.2%, 1.25%, 1.3%, 1.35%, 1.4%, 1.45%, 1.5%, 1.55%, 1.6%, 1.65%, 1.7%, or 1.75%, 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, but 1.5%-1.6% is further preferred.

[0053] Preferably, the degree of solubility of component A is 20-30°SR, for example, it can be 21°SR, 22°SR, 23°SR, 24°SR, 25°SR, 26°SR, 27°SR, 28°SR, 29°SR, 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.

[0054] Preferably, the bamboo fiber pulping is performed using a trough pulping machine.

[0055] Preferably, the pulp concentration of the bamboo fiber pulp is 0.3%-1%, for example, it can be 0.4%, 0.5%, 0.6%, 0.7%, 0.8% or 0.9%, 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.

[0056] Preferably, the gap between the flying knife and the bottom knife during the bamboo fiber pulping process is 0.05-0.2mm, for example, it can be 0.08mm, 0.1mm, 0.12mm, 0.15mm or 0.18mm, and the specific values ​​between the above points are not exhaustively listed in this invention due to space limitations and for the sake of brevity.

[0057] Preferably, the degree of solubility of component B is 18-26°SR, for example, it can be 19°SR, 20°SR, 21°SR, 22°SR, 23°SR, 24°SR or 25°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.

[0058] As a preferred technical solution of the present invention, the mixed beating of bleached sulfate wood pulp, bark pulp, and hemp pulp adopts conventional beating concentration and process, with a pulp concentration preferably of 1.1%-1.8%. The main function of the beating machine in the bleached sulfate wood pulp, bark pulp, and hemp pulp is to cut the fibers, primarily to change the average length of the fibers. When bamboo fibers are beated separately, a specific process is used to minimize the shearing effect on the fibers and ensure that the average length of the bamboo fibers changes very little. This is mainly achieved through inter-fiber friction, causing the bamboo fibers to "split," "tear," and "slip," primarily to improve the degree of fiber splitting and bristling. Therefore, the pulp concentration for bamboo fiber beating is 0.3%-1%. If the pulp concentration is too high (e.g., reaching the concentration of mixed beating of bleached sulfate wood pulp, bark pulp, and hemp pulp), the dispersibility of the bamboo fibers will be poor, resulting in phenomena such as entanglement, interweaving, and aggregation.

[0059] As a preferred technical solution of the present invention, a specific beating process is used to beneficiate bamboo fibers. By controlling the gap between the fly knife and the bottom knife to be 0.05-0.2mm, the shearing of the bamboo fibers by the fly knife and bottom knife during the beating process is reduced, and the fibers mainly rely on mutual friction, thereby improving the degree of fiber fibrillation. The freeness (beating degree) of component B after treatment is 18°SR-26°SR. At this point, the average length and dispersion of the bamboo fibers can meet the requirements for the preparation of high-performance paperboard. The specific beating process has a better effect on improving the performance and stability of the paperboard. Moreover, the increased degree of fiber fibrillation of the bamboo fibers after beating enhances the bonding force with BKP, bark pulp, and hemp pulp, which helps to further improve the strength of the paperboard.

[0060] Preferably, after mixing component A and component B, water is added to dilute the mixture to obtain the fiber suspension.

[0061] Preferably, the chitosan aqueous solution comprises a combination of chitosan, an acidic compound, and water.

[0062] Preferably, the mass ratio of chitosan to water is 1:(90-100), for example, it can be 1:91, 1:92, 1:93, 1:94, 1:95, 1:96, 1:97, 1:98 or 1:99, etc.

[0063] Preferably, the method for preparing the chitosan aqueous solution includes: dispersing chitosan in water, adding an acidic compound until the chitosan dissolves, and obtaining the chitosan aqueous solution.

[0064] Preferably, the acidic compound includes any one or a combination of at least two of formic acid, acetic acid, hydrochloric acid, and lactic acid, with acetic acid being more preferred.

[0065] Preferably, the mass ratio of the acidic compound to chitosan is (0.1-2):1, for example, it can be 0.2:1, 0.3:1, 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1 or 1.8:1, etc.

[0066] Preferably, the hot pressing method specifically includes: placing the wet paper basin blank in a high-temperature mold, pressing and drying it to obtain a paper basin blank.

[0067] Preferably, the hot pressing temperature 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.

[0068] Preferably, the punching method specifically includes: using a punching die to remove the central hole and edge material of the paper cone blank to obtain the speaker paper cone.

[0069] Preferably, the preparation method specifically includes:

[0070] Bleached sulfate wood pulp, bark pulp and hemp pulp are mixed and pulped to obtain component A with a beatability of 20-30°SR;

[0071] Bamboo fibers are pulped to a pulp consistency of 0.3%-1% and the gap between the fly knife and the bottom knife is 0.05-0.2mm to obtain component B with a beating degree of 18-26°SR.

[0072] Chitosan is dispersed in water at a mass ratio of 1:(90-100), and an acidic compound is added until the chitosan dissolves to obtain an aqueous chitosan solution.

[0073] Components A and B are mixed and diluted with water to obtain a fiber suspension;

[0074] The fiber suspension was mixed evenly with the chitosan aqueous solution and then filtered to obtain a wet paper basin preform.

[0075] The wet paper basin blank is placed in a high-temperature mold and hot-pressed at 150-200℃ to obtain a paper basin blank.

[0076] The central hole and edge material of the paper cone blank are removed by a punching die to obtain the speaker paper cone.

[0077] Thirdly, the present invention provides a loudspeaker comprising a loudspeaker cone as described in the first aspect.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] (1) In the speaker cone provided by the present invention, by using a specific amount of bleached sulfate wood pulp, bark pulp, hemp pulp, bamboo fiber and chitosan in combination, the fibers with different properties work synergistically and / or complement each other, and the components work synergistically to improve the strength of the cone and reduce the density, so that the speaker cone has a high Young's modulus and low density, thereby widening the frequency response range of the speaker and improving the sensitivity of the speaker; at the same time, the speaker cone has moderate internal damping, which can suppress the split vibration of the cone, make the frequency response characteristics of the speaker flatter, and improve the low-frequency sound quality of the speaker.

[0080] (2) The speaker cone provided by the present invention is a natural fiber composite cone. On the one hand, the use of natural fibers can reduce the amount of coniferous wood fiber used; on the other hand, BKP, bark pulp and hemp pulp are all white pulps, and the speaker cone prepared by compounding them with bamboo fiber has a special appearance that is different from ordinary cones.

[0081] (3) Through the design and compounding of components and the optimization of the preparation process, the Young's modulus of the speaker cone is 4.9-6.7 GPa and the density is 0.51-0.74 g / cm³. 3 With a loss factor of 0.042-0.085, it combines low density, high Young's modulus, appropriate internal damping, and high stability, making it a high-performance speaker cone. Detailed Implementation

[0082] 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.

[0083] 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.

[0084] The specific information of the materials used in the following specific embodiments of the present invention is as follows:

[0085] (1) Bleached sulfate wood pulp: BKP, purchased from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0086] (2) Bark pulp: purchased from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0087] (3) Hemp pulp: with an average length of 18mm and a fiber aspect ratio of 1100, purchased from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd.

[0088] (4) Bamboo fiber: average length of 15-50mm, ultra-long fiber rate (mass percentage of fiber ≥90mm) of 10%, short fiber rate (mass percentage of fiber <15mm) of 10%, linear density ≤2.5tex, breaking strength ≥2Cn / dtex, moisture content ≤10%, uniform color, no metallic foreign matter, no foreign fiber; purchased from Sichuan Changsheng New Material Technology Co., Ltd.

[0089] (5) Chitosan: Low viscosity chitosan (<200mPa·s), purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0090] Example 1

[0091] A loudspeaker cone and its preparation method, wherein the raw materials for preparing the loudspeaker cone comprise the following components in parts by weight:

[0092]

[0093] The method for preparing the speaker cone specifically includes the following steps:

[0094] (1) Mix BKP, bark pulp and hemp pulp and beat them to a pulping concentration of 1.57% to obtain component A with a beating degree of 25°SR;

[0095] Bamboo fibers were individually pulped using a trough pulper with a pulp consistency of 0.5% and a gap of 0.1 mm between the fly knife and the bottom knife to obtain component B with a beating degree of 18°SR.

[0096] Chitosan was dispersed in water at a mass ratio of 1:90 to chitosan to water. Glacial acetic acid was added dropwise until dissolved (the mass ratio of glacial acetic acid to chitosan was 1:5) to obtain an aqueous solution of chitosan.

[0097] (2) Mix component A and component B obtained in step (1), dilute with water to obtain a fiber suspension; mix the fiber suspension with chitosan aqueous solution, stir evenly, and filter to obtain a paper basin wet preform;

[0098] (3) The paper basin wet blank obtained in step (2) is placed in a high-temperature mold for hot pressing and molding, and the temperature is controlled at 180°C. After pressing and drying, a paper basin blank is obtained.

[0099] (4) The paper cone blank obtained in step (3) is punched using a punching die to remove the central hole and edge material, thereby obtaining the speaker paper cone.

[0100] Examples 2-9, Comparative Examples 1-5

[0101] A speaker cone differs from Example 1 only in the amount of components and / or the degree of percussion, as shown in Table 1, where "--" indicates that the component was not added; the preparation method of the speaker cone is the same as that of Example 1.

[0102] Table 1

[0103]

[0104]

[0105] Example 10

[0106] A speaker cone, which differs from Example 1 only in that, during the pulping of bamboo fiber in step (1), the gap between the flying knife and the bottom knife of the trough pulper is 0 mm, and the components and other preparation steps are the same as in Example 1.

[0107] Comparative Example 6

[0108] A speaker cone differs from Example 1 only in that bamboo fiber is replaced with an equal mass of rice straw fiber (unbleached rice straw fiber, purchased from Jinan Lexiu Zhibao E-commerce Co., Ltd.), while the other components, amounts, and preparation methods are the same as in Example 1.

[0109] Comparative Example 7

[0110] A speaker cone, which differs from Example 1 only in that, in step (1), chitosan is dispersed in water without the addition of glacial acetic acid to obtain a chitosan aqueous suspension; the components and other preparation steps are the same as in Example 1.

[0111] Comparative Example 8

[0112] A speaker cone differs from Example 1 only in that bamboo fibers are replaced with an equal mass of bamboo pulp (unbleached bamboo pulp, purchased from Guangzhou Yunqi Electroacoustic Technology Development Co., Ltd., with an initial freeness of 15°SR, which is then freed to 18°SR in a pulper and used as component B). All other components, amounts, and preparation methods are the same as in Example 1.

[0113] Comparative Example 9

[0114] A speaker cone differs from Example 1 only in that, in step (1), bamboo fiber is mixed with BKP, bark pulp and hemp pulp and pulped together to obtain pulp with a beating degree of 25°SR; the components, dosage and other preparation steps are the same as in Example 1.

[0115] The performance of the speaker cones provided in Examples 1-10 and Comparative Examples 1-9 was tested using the following methods:

[0116] (1) Density: The mass / volume method was used. The mass of the paper basin was measured by an electronic balance, the thickness of the paper basin was measured by a micrometer, and the volume of the paper basin was calculated by a 3D model of the paper basin.

[0117] (2) Young's modulus: The Young's modulus of the paper cone was tested using the Material Parameter Testing Module (MPM) in KLIPPEL R&D SYSTEM to characterize its strength;

[0118] (3) Loss factor: The loss factor of the paper cone was tested using the Material Parameter Test Module (MPM) in KLIPPEL R&D SYSTEM to characterize its damping.

[0119] The test results are shown in Table 2:

[0120] Table 2

[0121]

[0122]

[0123] As shown in Table 2, the test data of this invention, through the synergistic interaction of bleached sulfate wood pulp, bark pulp, hemp pulp, bamboo fiber, and chitosan, and the synergistic / complementary properties of fibers with different characteristics, and the synergistic effect between components, can effectively improve the strength of the speaker cone, reduce its density, and provide appropriate internal damping. This results in speaker cones provided in Examples 1-5 having a Young's modulus of 4.9-6.7 GPa and a density of 0.51-0.74 g / cm³. 3 It has a loss factor of 0.042-0.085 and combines low density, high Young's modulus, appropriate internal damping and high stability.

[0124] In this invention, by designing and optimizing the amount of bamboo fiber used and the pulping process, the bamboo fiber can be evenly dispersed in the cone and has a stronger binding force with other components, thereby enabling the speaker cone to maintain an excellent balance between multiple properties such as low density, high strength, and suitable internal damping.

[0125] A comparison of Examples 1 and 6 shows that when too much bamboo fiber is added, the bamboo fiber will flocculate during dispersion, resulting in uneven dispersion of the bamboo fiber in the paper cone, which in turn leads to a decrease in the strength of the paper cone. A comparison of Examples 1 and 7 shows that when too little bamboo fiber is added, the density of the paper cone increases.

[0126] A comparison of Examples 1 and 8 shows that if the beating degree of bamboo fibers is too low during the pulping process, the length difference of bamboo fibers is large, the degree of fibrillation is low, and the strength of the paper cone decreases. A comparison of Examples 1 and 9 shows that when the beating degree of bamboo fibers is too high, the hollow structure of bamboo fibers is destroyed, resulting in an increase in the density of the paper cone.

[0127] As can be seen from the comparison between Example 1 and Example 10, when bamboo fibers are pulped, the gap between the fly knife and the bottom knife of the trough pulper is reduced to 0mm. At this time, the shearing force on the bamboo fibers is enhanced, the fiber length is shortened, but the degree of fibrillation is reduced, which in turn leads to a decrease in the loss factor of the paper tray and the internal damping performance cannot meet the requirements.

[0128] The speaker cone provided by this invention uses a combination of bleached sulfate wood pulp, bark pulp, hemp pulp, bamboo fiber and chitosan as raw materials. The fibers with different properties work synergistically and / or complement each other, and are compounded with chitosan to make the speaker cone have high strength and Young's modulus, low density and suitable internal damping characteristics.

[0129] As can be seen from Comparative Examples 1-5, if any of the following raw materials are missing from the paper cone: bleached sulfate wood pulp (BKP), bark pulp, hemp pulp, bamboo fiber, or chitosan, the paper cone cannot simultaneously achieve high modulus, low density, and appropriate internal damping.

[0130] As can be seen from the comparison between Example 1 and Comparative Example 6, when other natural fibers, such as straw fibers, are used in speaker cones, the Young's modulus of the cone is lower.

[0131] As can be seen from the comparison between Example 1 and Comparative Example 7, if no acidic compound is added, chitosan cannot dissolve in water to form an aqueous solution. The undissolved chitosan has poor binding force with plant fiber, and most of the chitosan will be lost with water in step (2), which will lead to a decrease in the Young's modulus of the paper basin.

[0132] As can be seen from the comparison between Example 1 and Comparative Example 8, the molecular structure of bamboo pulp is destroyed during the pulping process, and bamboo pulp does not have a hollow structure. Therefore, when bamboo pulp of the same mass is used to replace bamboo fiber to prepare speaker cones, the density of the cones increases significantly and the loss factor decreases, resulting in a significant deterioration in sound quality and listening experience.

[0133] As can be seen from the comparison between Example 1 and Comparative Example 9, when bamboo fiber is mixed and beaten with BKP, bark pulp and hemp pulp, under conventional beating process, the high pulp concentration results in poor dispersion of bamboo fiber, leading to phenomena such as entanglement, interlacing and aggregation. Moreover, the effect of conventional beating process on the fiber is to cut and change the average length of the fiber. The length of bamboo fiber is reduced after mixed beating, but the degree of fibrillation is not improved, resulting in poor improvement of paperboard performance. Due to the different fiber morphology and properties, bamboo fiber, BKP, bark pulp and hemp pulp cannot simultaneously reach the state most suitable for paperboard making, resulting in the inability to achieve high modulus, low density and appropriate internal damping of paperboard performance.

[0134] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate the speaker 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, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A speaker cone, characterized in that, The raw materials for preparing the speaker cone include the following components in parts by weight: 20-70 parts of bleached sulfate wood pulp; 5-40 parts bark sap; 5-40 portions of sesame paste; Bamboo fiber 2-50 parts; Chitosan 0.1-3 parts, and acidic compounds; The average fiber length of the hemp pulp is 10-30 mm; The fiber aspect ratio of the hemp pulp is (800-1300):1; The average length of the bamboo fiber is 15-50 mm. The linear density of the bamboo fiber is ≤2.5 tex; The breaking strength of the bamboo fiber is ≥2 Cn / dtex; The moisture content of the bamboo fiber is ≤10%; The viscosity of the chitosan is <200 mPa·s; The acidic compound includes any one or a combination of at least two of formic acid, acetic acid, hydrochloric acid, and lactic acid; The mass ratio of the acidic compound to chitosan is (0.1-2):

1.

2. The speaker cone according to claim 1, characterized in that, The raw materials for preparing the speaker cone include the following components in parts by weight: 30-60 parts of bleached sulfate wood pulp; 10-30 parts bark sap; 10-30 portions of sesame paste; Bamboo fiber 5-40 parts; Chitosan 0.5-2 parts.

3. The speaker cone according to claim 1, characterized in that, The average fiber length of the hemp pulp is 15-20 mm.

4. A method for preparing a loudspeaker cone as described in any one of claims 1-3, characterized in that, The preparation method includes: Bleached sulfate wood pulp, bark pulp, and hemp pulp were mixed and pulped to obtain component A; bamboo fiber was pulped to obtain component B. Component A and component B are mixed to obtain a fiber suspension; The fiber suspension was mixed evenly with the chitosan aqueous solution and then filtered to obtain a wet paper basin preform. The wet paper basin blank is hot-pressed to obtain a paper basin blank; The paper cone blank is punched to obtain the speaker cone.

5. The preparation method according to claim 4, characterized in that, The degree of solubility of component A is 20-30°SR.

6. The preparation method according to claim 4, characterized in that, The pulp consistency of the bamboo fiber pulp is 0.3%-1%.

7. The preparation method according to claim 4, characterized in that, The gap between the flying knife and the bottom knife during the pulping process of the bamboo fiber is 0.05-0.2 mm.

8. The preparation method according to claim 4, characterized in that, The degree of solubility of component B is 18-26°SR.

9. The preparation method according to claim 4, characterized in that, After mixing component A and component B, water is added to dilute the mixture to obtain the fiber suspension.

10. The preparation method according to claim 4, characterized in that, The chitosan aqueous solution comprises a combination of chitosan, an acidic compound, and water.

11. The preparation method according to claim 10, characterized in that, The mass ratio of chitosan to water is 1:(90-100).

12. The preparation method according to claim 10, characterized in that, The method for preparing the chitosan aqueous solution includes: dispersing chitosan in water, adding an acidic compound until the chitosan dissolves, and obtaining the chitosan aqueous solution.

13. The preparation method according to claim 4, characterized in that, The hot pressing method specifically includes: placing the wet paper basin blank in a high-temperature mold, pressing and drying it to obtain a paper basin blank.

14. The preparation method according to claim 13, characterized in that, The hot pressing temperature is 150-200℃.

15. The preparation method according to claim 4, characterized in that, The punching method specifically includes: using a punching die to remove the central hole and edge material of the paper cone blank to obtain the speaker paper cone.

16. A loudspeaker, characterized in that, The loudspeaker includes a loudspeaker cone as described in any one of claims 1-3.

Images