Novel mica foaming paper cone preparation method and mica paper cone loudspeaker

Abstract

The invention relates to the technical field of mica cone loudspeakers, in particular to a novel mica foaming cone preparation method and a mica cone loudspeaker. Paper pulp, long stapled cotton pulp, mica pre-dispersion, nano silicon dioxide suspension, a thermal expansion type polymer foaming agent and nano modified lignin fibers are used as raw materials; the novel mica foaming cone with a double-waterproof structure is formed through mixing, dispersing, papermaking, temperature gradient foaming, waterproof treatment and drying, so that the internal loss of the cone is improved, the sound pressure of a low-frequency band of a loudspeaker is effectively enhanced, the bass performance is fuller and more elastic, the bass sound effect of the loudspeaker is remarkably improved, and the overall acoustic quality is improved. The bonding strength of the mica and the foaming base material is improved through molecular-level interface modification, the service life is prolonged, the IPX5 waterproof grade requirement is met, the weight is reduced, meanwhile, the load of a loudspeaker vibration part is reduced, magnetic circuit loss in magnetic circuit design is reduced, the production and energy consumption cost of a loudspeaker is reduced, and the market competitiveness of a product is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mica paper cone loudspeaker, and particularly relates to a novel mica foamed paper cone preparation method and a mica paper cone loudspeaker. BACKGROUND

[0002] The mica paper cone loudspeaker is a kind of loudspeaker combining mica material and paper cone structure, and the paper cone material is usually based on paper pulp and mixed with mica and other reinforcing materials. The combination of the paper pulp and the mica and other reinforcing materials can significantly improve the rigidity and heat resistance of the diaphragm. Although the mica paper cone improves the distortion performance, the research on the sound quality, especially the low frequency band, is insufficient, which leads to the weak sound pressure level of the loudspeaker in the 50-200Hz low frequency band, the muddy and lack of level of bass performance, and the difficulty in meeting the user's demand for high-quality low-frequency sound effect. Moreover, the existing mica paper cone loudspeaker only meets the performance requirements of general indoor scenes, and does not consider the requirements of outdoor, bathroom and other humid or water-involved scenes. The paper cone is prone to deformation, mildew and other problems due to moisture, which seriously affects the service life and acoustic performance of the loudspeaker and limits the expansion of the application range. In addition, the interface bonding force between the mica fiber and the high polymer material is weak, and the long-term vibration is prone to delamination, which affects the service life and stability of the loudspeaker. SUMMARY

[0003] In order to overcome the shortcomings and deficiencies in the prior art, the purpose of the present application is to provide a novel mica foamed paper cone preparation method, which is simple to operate, convenient to control, high in production efficiency and low in production cost, and can be used for large-scale production. The novel mica foamed paper cone with a double waterproof structure is formed by using paper pulp, long-fiber cotton pulp, mica pre-dispersion, nano-silicon dioxide suspension, heat-expandable high polymer foaming agent and nano-modified lignin fiber as raw materials through mixing, dispersion, papermaking, temperature gradient foaming, waterproof treatment and drying. The paper cone internal loss is improved, the sound pressure level of the loudspeaker in the low frequency band (50-200Hz) is effectively strengthened, the bass performance is more full and elastic, the bass sound effect of the loudspeaker is significantly improved, the overall acoustic quality is improved, the bonding strength between the mica and the foamed substrate is improved through molecular level interface modification, the paper cone does not delaminate after long-term vibration, the service life is prolonged, the IPX5 waterproof grade requirement is met, the weight is reduced, the load of the loudspeaker vibration part is reduced, the magnetic circuit loss in the magnetic circuit design is reduced, the production and energy consumption costs of the loudspeaker are reduced, and the market competitiveness of the product is improved.

[0004] Another purpose of the present application is to provide a mica paper cone loudspeaker, which significantly improves the bass sound effect of the loudspeaker, has lower total harmonic distortion, and improves the overall acoustic quality.

[0005] The purpose of the present application is achieved by the following technical scheme: a novel mica foamed paper cone preparation method, comprising the following steps: (S1), put mica powder and γ-aminopropyl triethoxysilane into a high-speed dispersion machine, add ethanol, and stir at 70-90℃ and 1300-1800r / min for 20-50min to form a mica pre-dispersion; (S2), add deionized water to nano-silica, and treat with an ultrasonic disperser for 15-25min to form a nano-silica suspension; (S3), put paper pulp and long-fiber cotton pulp into a hydraulic pulper, and disintegrate at 50-60℃ for 30-40min to obtain mixed paper pulp; (S4), add the mica pre-dispersion, nano-silica suspension, heat-expandable polymer foaming agent, and nano-modified lignin fiber to the mixed paper pulp in sequence, disperse at 600-1000r / min for 15-25min, and adjust the concentration to 6-7wt% to form a paper pulp suspension; (S5), use a papermaking process to make the paper pulp suspension on a forming mold, control the thickness of the formed paper basin to be 0.8-1.2mm, then dry at low temperature of 60-80℃ for 2-3h, and then increase the temperature to 120-140℃ for high-temperature drying for 1h, to form a gradient porous structure with a center foaming rate of 30-40% and an edge foaming rate of 10-15% through temperature gradient induction, to obtain a dried paper basin; (S6), completely immerse the dried paper basin in a nano-silica and fluorine-nano-siloxane waterproof agent solution, soak at room temperature for 30-60min, and then dry at 80-100℃ for 20-30min to form a new mica foamed paper basin with a double waterproof structure.

[0006] The mica pre-dispersion obtained in step (S1) ensures that the γ-aminopropyl triethoxysilane is firmly combined with the mica surface hydroxyl group through a siloxane bond, improving the subsequent interfacial compatibility with the base material. The nano-silica suspension obtained in step (S2) is uniformly dispersed, avoiding nano-particle agglomeration and ensuring uniform distribution in the paper pulp. In step (S6), soaking for 30-60min ensures that the waterproof agent penetrates into the fiber gap, and the double waterproof structure is beneficial to balancing water resistance and air permeability.

[0007] Preferably, in step (S1), the addition amount of γ-aminopropyl triethoxysilane is 1%-2% of the mass of mica powder. γ-aminopropyl triethoxysilane is beneficial to improving the bonding strength of mica powder and foaming base material, so that the paper basin does not delaminate after long-term vibration, and the service life is prolonged. The solid-liquid ratio of the mica pre-dispersion is 1:4-6; the mica powder is white mica powder with a particle size of 10-50μm, which is used to optimize the vibration response and high-frequency performance of the paper basin due to its high rigidity and acoustic conductivity.

[0008] Preferably, in the step (S2), the ultrasonic disperser has a power of 300 W, and the nanosilica is a special silica sol for papermaking, which has a high specific surface area and surface hydroxyl characteristics, thereby improving the surface density of the paper cone, assisting in enhancing the waterproof performance, and optimizing the uniformity of acoustic conduction; the concentration of the nanosilica suspension is 4-6 wt%.

[0009] Preferably, in the steps (S3) and (S4), the weight amounts of the raw materials are as follows: paper pulp 50-60 parts, long-fiber cotton pulp 10-15 parts, mica pre-dispersion 120-150 parts, nanosilica suspension 10-25 parts, thermal expansion type polymer foaming agent 5-10 parts, and nanomodified lignin fiber 1-3 parts.

[0010] Further, in the steps (S3) and (S4), the paper pulp is unbleached sulfite coniferous pulp; and the thermal expansion type polymer foaming agent is selected from type UM118, which has an average particle size of 20-35 μm and an initial foaming temperature of 145-155 °C.

[0011] The unbleached sulfite coniferous pulp is beneficial to ensure the fiber length and bonding force, thereby providing a basic structural support for the paper cone. The long-fiber cotton pulp is beneficial to enhance the entanglement degree between fibers, thereby improving the damping characteristics of the paper cone and making the bass performance more full. The thermal expansion type polymer foaming agent itself has a core-shell structure (the shell is a thermoplastic polymer, and the core is a low-boiling-point hydrocarbon), and the foaming pore size is controlled to be 5-20 μm through the core-shell structure, which is more beneficial to balance the lightweight and structural strength.

[0012] Preferably, in the step (S4), the nanomodified lignin fiber is a nanomodified lignin fiber which is subjected to plasma surface roughening treatment and then pre-modified with silane coupling agent KH-550. Through the surface roughening and pre-modification of the fiber, the interfacial bonding force between the nanomodified lignin fiber and the paper pulp and mica powder is enhanced, the toughness of the paper cone is significantly improved, the tearing risk under high-power vibration is reduced, and the internal loss characteristics of the paper cone are simultaneously optimized.

[0013] Further, the plasma surface roughening treatment is performed by using a radio frequency plasma generator, argon gas is selected, the treatment is performed at a frequency of 13.56 MHz, a power of 100-300 W, a gas pressure of 50-100 Pa, and for 2-5 min, so that the contact angle of the nanomodified lignin fiber is reduced to less than 30°. The treatment is performed under low power conditions to avoid excessive degradation of the fiber, and is performed under low pressure conditions to enhance the plasma activity and simultaneously avoid fiber breakage caused by long treatment time. The pre-modification with silane coupling agent KH-550 is performed by immersing the nanomodified lignin fiber in silane coupling agent KH-550 with a concentration of 1-5 wt% under stirring conditions at a speed of 500 rpm and a temperature of 80 °C for 2-4 h, and then drying.

[0014] Preferably, in the step (S5), the center foaming pore diameter of the gradient porous structure is 15-20 mu m, and the edge foaming pore diameter of the gradient porous structure is 5-10 mu m, which is more favorable for balancing lightweight and structural strength.

[0015] Preferably, in the step (S6), the concentration of the nanometer silicon dioxide and fluorine-nano-siloxane waterproof agent solution is 15-20 wt%, and the fluorine-nano-siloxane waterproof agent is selected from type YX-608; the double waterproof structure is composed of a surface fluorine hydrophobic layer (thickness 0.1-0.3 mu m) and an inner layer nanometer silicon dioxide penetration network, so that a dense waterproof film is formed on the surface of the paper basin, and the nanometer silicon dioxide penetrates from the deep inside to build a waterproof network, greatly improving the waterproof and moisture-proof performance of the loudspeaker, meeting the use requirements in humid scenes such as outdoor and bathroom, and expanding the application scenarios of the loudspeaker.

[0016] Another object of the application is achieved by the following technical scheme: a mica paper basin loudspeaker, comprising a basin frame, a hollow paper basin fixedly connected to the top of the basin frame, a dustproof cover arranged in the middle of the hollow paper basin, a voice coil fixedly connected to the inner ring of the hollow paper basin, a spring connected to the basin frame and the voice coil, and a magnetic circuit system fixedly connected to the bottom of the basin frame, wherein the dustproof cover is a lightweight ABS dustproof cover, and the hollow paper basin is prepared by the novel mica foaming paper basin preparation method described above. The vibration system composed of the lightweight ABS dustproof cover and the novel mica foaming paper basin can reduce the weight of the vibration system by 5-10% compared with similar loudspeaker vibration systems, effectively reducing the magnetic circuit load and energy consumption.

[0017] Preferably, the magnetic circuit system comprises a dust cup fixedly connected to the bottom of the basin frame, a magnet ring connected to the bottom of the dust cup, a T-shaped iron connected to the bottom of the magnet ring, a copper short circuit ring sleeved on the outer periphery of the top of the core column of the T-shaped iron, an aluminum short circuit ring integrally arranged on the outer periphery of the core column of the T-shaped iron, and a dust screen arranged on the top of the core column of the T-shaped iron, wherein the T-shaped iron and the dust cup have an annular magnetic gap for the voice coil to extend into, the middle of the core column of the T-shaped iron is provided with a ventilation through hole, and the top of the core column of the T-shaped iron is provided with a limiting groove in communication with the ventilation through hole and used for containing the dust screen. The copper short circuit ring and the aluminum short circuit ring jointly suppress the induced eddy current of the voice coil, reduce the non-linear distortion of the magnetic circuit, improve the low-frequency response and damping characteristics of the loudspeaker, and make the transient performance of the sound better.

[0018] The new mica foamed paper pot preparation method of the application has the following beneficial effects: (1) the introduction of a heat-expandable polymer foaming agent and long-fiber cotton pulp improves the internal damage of the paper pot under the same conditions, effectively strengthens the sound pressure level of the low-frequency band (50-200 Hz) of the horn, makes the bass performance more full and elastic, significantly improves the bass sound effect of the horn, and improves the overall acoustic quality; (2) the introduction of gamma-aminopropyl triethoxysilane improves the bonding strength of the mica powder and the foaming base material through molecular-level interface modification, so that the paper pot does not have delamination phenomenon during long-time vibration, and the service life is prolonged; (3) the soaking of nano-silicon dioxide and fluorine-nano-siloxane composite waterproof agent solution through the immersion process forms a dense waterproof film on the surface of the paper pot, while the nano-siloxane penetrates from the inside to build a waterproof network, greatly improves the waterproof and moisture-proof performance of the horn, meets the IPX5 waterproof level, and meets the use requirements of outdoor, bathroom and other humid scenes, expanding the application scenarios of the horn; (4) the paper pot adopts a foaming process and a lightweight formula, which reduces the weight under the same specification, reduces the load of the horn vibration component, reduces the magnetic circuit loss in the magnetic circuit design, thereby reducing the production and energy consumption cost of the horn, and improving the market competitiveness of the product; (5) the bass sound effect of the new mica foamed paper pot is more targeted in the low-frequency band, and the subjective listening experience of the bass elasticity and fullness is better.

[0019] The mica paper pot horn of the application comprises a pot frame, a hollow paper pot fixedly connected to the top of the pot frame, a dust cover arranged in the middle of the hollow paper pot, a voice coil fixedly connected to the inner ring of the hollow paper pot, a spring connected to the pot frame and the voice coil, and a magnetic circuit system fixedly connected to the bottom of the pot frame, and a lightweight ABS dust cover and a new mica foamed paper pot form a vibration system, the weight of the vibration system can be reduced by 5-10% compared with the vibration system of the same type of horn, effectively reducing the magnetic circuit load and energy consumption. In the anechoic chamber, the frequency response curve of the horn is tested, compared with the sound pressure level of the low-frequency band of the conventional horn, the sound pressure level of the low-frequency band (50-200 Hz) is verified to be increased by ≥2dB, the total harmonic distortion (THD) is ≤2% under the condition of 1W / 1m, and the total harmonic distortion is lower than that of the conventional horn. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a structural schematic diagram of the application; Figure 2 is an exploded schematic diagram of the application; Figure 3 is an exploded schematic diagram of the application from another perspective; Figure 4 is a cross-sectional schematic diagram of the application; Figure 5 is a frequency response graph of the application test, wherein the green curve is the frequency response test result of the paper pot horn of example 1, and the red curve is the frequency response test result of the paper pot horn of comparative example 1; Figure 6 This is a total harmonic distortion (THD) graph tested by the present invention. The green curve represents the THD test result of the paper cone speaker in Example 1, and the red curve represents the THD test result of the paper cone speaker in Comparative Example 1.

[0021] The attached diagram is labeled as follows: 1. Sink frame; 2. Hollow paper cone; 3. Dust cover; 4. Voice coil; 5. Spider; 6. Magnetic circuit system; 61. Washer; 62. Magnet ring; 63. T-iron; 64. Copper short-circuit ring; 65. Aluminum short-circuit ring; 66. Dustproof mesh; 7. Annular magnetic gap; 8. Ventilation hole; 9. Limiting groove. Detailed Implementation

[0022] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0023] Example 1 like Figures 1-4 As shown, a mica paper cone speaker includes a frame 1, a hollow paper cone 2 fixedly connected to the top of the frame 1, a dust cover 3 covering the middle of the hollow paper cone 2, a voice coil 4 fixedly connected to the inner ring of the hollow paper cone 2, a spider 5 connected to the frame 1 and the voice coil 4, and a magnetic circuit system 6 fixedly connected to the bottom of the frame 1. The dust cover 3 is a lightweight ABS dust cover 3, and the hollow paper cone 2 adopts a new type of mica foam paper cone.

[0024] The magnetic circuit system 6 includes a washer 61 fixedly connected to the bottom of the frame 1, a magnet ring 62 connected to the bottom of the washer 61, a T-iron 63 connected to the bottom of the magnet ring 62, a copper short-circuit ring 64 sleeved on the outer periphery of the top of the core post of the T-iron 63, an aluminum short-circuit ring 65 integrally formed on the outer periphery of the core post of the T-iron 63, and a dustproof net 66 covering the top of the core post of the T-iron 63. There is an annular magnetic gap 7 between the core post of the T-iron 63 and the washer 61 for the voice coil 4 to extend into. A vent hole 8 is opened in the middle of the core post of the T-iron 63, and a limiting groove 9 is opened on the top of the core post of the T-iron 63, which communicates with the vent hole 8 and is used to accommodate the dustproof net 66.

[0025] The method for preparing the novel mica foamed paper basin includes the following steps: (S1) Mica powder and γ-aminopropyltriethoxysilane were put into a high-speed disperser, and ethanol was added. The mixture was stirred at 80°C and 1500 r / min for 30 min to form a mica pre-dispersion. (S2) Add deionized water to nano-silica and treat with an ultrasonic disperser for 20 minutes to form a nano-silica suspension; (S3) Put the pulp and long-staple cotton pulp into a hydrapulper and break them down at 55°C for 35 minutes to obtain mixed pulp; (S4), adding mica pre-dispersion, nano-silica suspension, thermal expansion type polymer foaming agent and nano-modified lignin fiber into the mixed pulp in sequence, dispersing for 20 min under 800 r / min stirring speed, and adjusting the concentration to 6.5 wt% to form a pulp suspension; (S5), using papermaking process to make the pulp suspension on a forming mold, controlling the thickness of the formed paper basin to be 1 mm, then drying at 70℃ low temperature for 2.5 h, and then increasing the temperature to 130℃ high temperature for 1 h, to form a gradient porous structure with a center foaming rate of 35% and an edge foaming rate of 13% through temperature gradient induction, to obtain a dried paper basin; (S6), completely immersing the dried paper basin into a nano-silica and fluorine-nano-siloxane waterproof agent solution, soaking at room temperature for 40 min, and then drying at 90℃ for 25 min to form a new mica foaming paper basin with a double waterproof structure.

[0026] In the step (S1), the addition amount of the γ-aminopropyl triethoxysilane accounts for 1.5% of the mass of the mica powder, and the solid-liquid ratio of the mica pre-dispersion is 1:5; the mica powder is white mica powder with an average particle size of 20 μm.

[0027] In the step (S2), the power of the ultrasonic disperser is 300 W, and the nano-silica is a special silica sol for papermaking; the concentration of the nano-silica suspension is 5 wt%.

[0028] In the steps (S3) and (S4), the weight amount of each raw material is as follows: pulp 55 parts, long-fiber cotton pulp 12 parts, mica pre-dispersion 135 parts, nano-silica suspension 18 parts, thermal expansion type polymer foaming agent 8 parts, and nano-modified lignin fiber 2 parts.

[0029] In the steps (S3) and (S4), the pulp is unbleached sulfite coniferous pulp; the thermal expansion type polymer foaming agent is selected from type UM118, and the average particle size thereof is 28 μm, and the initial foaming temperature is 145℃.

[0030] In the step (S4), the nano-modified lignin fiber is a nano-modified lignin fiber which is subjected to plasma surface roughening treatment and then pre-modified with silane coupling agent KH-550. The plasma surface roughening treatment is performed by using a radio frequency plasma generator, and argon gas is selected as the gas, and the treatment is performed under the conditions of a frequency of 13.56 MHz, a power of 300 W, and a gas pressure of 80 Pa for 3 min, so that the contact angle of the nano-modified lignin fiber is reduced to less than 30°. The pre-modification with the silane coupling agent KH-550 is performed by immersing the nano-modified lignin fiber in a solution of the silane coupling agent KH-550 with a concentration of 2 wt% under the conditions of a temperature of 80℃ and a stirring speed of 500 rpm for 3 h, and then drying.

[0031] In the step (S5), the average foaming pore diameter of the center of the gradient porous structure is 18 μm, and the average foaming pore diameter of the edge of the gradient porous structure is 8 μm.

[0032] In the step (S6), the concentration of the nanosilica and fluorine-nanosiloxane waterproof agent solution is 18 wt%, and the fluorine-nanosiloxane waterproof agent is selected from a type YX-608; the double waterproof structure is composed of a surface fluorine hydrophobic layer (thickness 0.2 μm) and an inner nanosiloxane penetration network.

[0033] The new mica foamed paper pot is subjected to waterproof test according to ISO 20653, and meets the IPX5 waterproof level.

[0034] Example 2 The difference between the present example and Example 1 is that: The preparation method of the new mica foamed paper pot comprises the following steps: (S1), the mica powder and γ-aminopropyl triethoxysilane are put into a high-speed dispersing machine, and after adding ethanol, stirring is carried out at 70°C and 1800 r / min for 50 min to form a mica pre-dispersion; (S2), deionized water is added to the nanosilica, and an ultrasonic dispersing instrument is used for treatment for 15 min to form a nanosilica suspension; (S3), the paper pulp and long-fiber cotton pulp are put into a hydraulic pulper, and are disintegrated at 50°C water temperature for 40 min to obtain mixed paper pulp; (S4), the mica pre-dispersion, the nanosilica suspension, the heat-expandable polymer foaming agent and the nanomodified lignin fiber are sequentially added to the mixed paper pulp, and are dispersed at a stirring speed of 600 r / min for 25 min, while the concentration is adjusted to 6 wt% to form a paper pulp suspension; (S5), the paper pulp suspension is formed on a forming mold by using a papermaking process, the thickness of the formed paper pot is controlled to be 0.8 mm, then low-temperature drying is carried out at 60°C for 3 h, and high-temperature drying is carried out at 120°C for 1 h, so as to form a gradient porous structure with a center foaming rate of 30% and an edge foaming rate of 10% through temperature gradient induction, and a dry paper pot is obtained; (S6), the dry paper pot is completely immersed in a nanosilica and fluorine-nanosiloxane waterproof agent solution, and after soaking at room temperature for 30 min, drying is carried out at 80°C for 30 min to form a new mica foamed paper pot with a double waterproof structure.

[0035] In the step (S1), the addition amount of the γ-aminopropyl triethoxysilane accounts for 1% of the mass of the mica powder, and the solid-liquid ratio of the mica pre-dispersion is 1:4; the mica powder is white mica powder with an average particle size of 10 μm.

[0036] In the step (S2), the power of the ultrasonic disperser is 300 W, and the nano-silica is a special silica sol for papermaking; the concentration of the nano-silica suspension is 5 wt%.

[0037] In the steps (S3) and (S4), the weight of each raw material is as follows: pulp 50 parts, long-fiber cotton pulp 15 parts, mica pre-dispersion 120 parts, nano-silica suspension 10 parts, thermal expansion type polymer foaming agent 5 parts, and nano-modified lignin fiber 1 part.

[0038] In the steps (S3) and (S4), the pulp is unbleached sulfite coniferous pulp; the thermal expansion type polymer foaming agent is selected from type UM118, and the average particle size is 20 μm, and the initial foaming temperature is 145℃.

[0039] In the step (S4), the nano-modified lignin fiber is a nano-modified lignin fiber after plasma surface roughening treatment and pre-modification treatment with silane coupling agent KH-550. The plasma surface roughening treatment is performed by using a radio frequency plasma generator, and argon gas is selected as the gas, and the treatment is performed under the conditions of a frequency of 13.56 MHz, a power of 300 W, and a gas pressure of 80 Pa for 2 min, so that the contact angle of the nano-modified lignin fiber is reduced to less than 30°. The pre-modification treatment with the silane coupling agent KH-550 is performed by immersing the nano-modified lignin fiber in a solution of the silane coupling agent KH-550 with a concentration of 2 wt% under the conditions of a temperature of 80℃ and a stirring speed of 500 rpm for 2 h, and then drying.

[0040] In the step (S5), the average foaming pore size of the center of the gradient porous structure is 15 μm, and the average foaming pore size of the edge of the gradient porous structure is 5 μm.

[0041] In the step (S6), the concentration of the nano-silica and the fluorine-nano-siloxane waterproof agent solution is 15 wt%, the fluorine-nano-siloxane waterproof agent is selected from type YX-608; and the double waterproof structure is composed of a fluorine hydrophobic layer (0.2 μm in thickness) on the surface and a nano-siloxane penetration network in the inner layer.

[0042] The new mica foamed paper pot is subjected to waterproof test according to ISO 20653, and meets the IPX5 waterproof level.

[0043] Example 3 The difference between the present example and Example 1 is that: The preparation method of the new mica foamed paper pot comprises the following steps: (S1), the mica powder and γ-aminopropyl triethoxysilane are put into a high-speed disperser, and then ethanol is added, and the mixture is stirred at 90℃ and 1300 r / min for 20 min to form a mica pre-dispersion; (S2), adding deionized water to the nanometer silicon dioxide, and treating with an ultrasonic disperser for 25 min to form a nanometer silicon dioxide suspension; (S3), putting the paper pulp and long-fiber cotton pulp into a hydraulic pulper, and disintegrating at a water temperature of 60 DEG C for 30 min to obtain a mixed paper pulp; (S4), adding a mica pre-dispersion, the nanometer silicon dioxide suspension, a heat-expandable polymer foaming agent, and nanometer modified lignin fibers to the mixed paper pulp in sequence, and dispersing at a stirring speed of 1000 r / min for 15 min while adjusting the concentration to 7 wt% to form a paper pulp suspension; (S5), using a papermaking process to make the paper pulp suspension on a forming mold, controlling the thickness of the formed paper basin to be 1.2 mm, then drying at a low temperature of 80 DEG C for 2 h, and then increasing the temperature to a high temperature of 140 DEG C for 1 h to form a gradient porous structure with a center foaming rate of 40% and an edge foaming rate of 15% through temperature gradient induction, and obtaining a dried paper basin; (S6), completely immersing the dried paper basin in a nanometer silicon dioxide and fluorine-nanometer siloxane waterproof agent solution, soaking at room temperature for 60 min, and then drying at a temperature of 100 DEG C for 20 min to form a new mica foamed paper basin with a double waterproof structure.

[0044] In the step (S1), the addition amount of the γ-aminopropyl triethoxysilane accounts for 2% of the mass of the mica powder, and the solid-liquid ratio of the mica pre-dispersion is 1:6; the mica powder is white mica powder with an average particle size of 50 μm.

[0045] In the step (S2), the power of the ultrasonic disperser is 300 W, and the nanometer silicon dioxide is a special silicon sol for papermaking; the concentration of the nanometer silicon dioxide suspension is 5 wt%.

[0046] In the steps (S3) and (S4), the weight amount of each raw material is as follows: paper pulp 60 parts, long-fiber cotton pulp 10 parts, mica pre-dispersion 150 parts, nanometer silicon dioxide suspension 25 parts, heat-expandable polymer foaming agent 10 parts, and nanometer modified lignin fibers 3 parts.

[0047] In the steps (S3) and (S4), the paper pulp is unbleached sulfite coniferous pulp; the heat-expandable polymer foaming agent is selected from a type UM118, and has an average particle size of 35 μm and an initial foaming temperature of 145 DEG C.

[0048] In the step (S4), the nano-modified lignin fiber is a nano-modified lignin fiber treated by plasma surface roughening and then pre-modified by silane coupling agent KH-550. The plasma surface roughening treatment is performed by using a radio frequency plasma generator, argon gas is selected, and the treatment is performed under the conditions of a frequency of 13.56 MHz, a power of 300 W, a gas pressure of 80 Pa, and a treatment time of 5 min, so that the contact angle of the nano-modified lignin fiber is reduced to less than 30°. The pre-modification treatment by the silane coupling agent KH-550 is performed by immersing the nano-modified lignin fiber in a solution of the silane coupling agent KH-550 with a concentration of 2 wt% at 80℃ and a stirring speed of 500 rpm for 4 h, and then drying.

[0049] In the step (S5), the average foaming pore diameter of the center of the gradient porous structure is 20 μm, and the average foaming pore diameter of the edge of the gradient porous structure is 10 μm.

[0050] In the step (S6), the concentration of the nano-silica and fluorine-nano-siloxane waterproof agent solution is 20 wt%, the fluorine-nano-siloxane waterproof agent is selected from YX-608, and the double waterproof structure is composed of a fluorine hydrophobic layer (0.2 μm in thickness) and an inner layer of a nano-siloxane penetration network.

[0051] The new mica foamed paper pot meets the IPX5 waterproof level according to the waterproof test of ISO 20653.

[0052] Comparative Example 1 The difference between the present comparative example and Example 1 is that: The hollow paper pot is a loudspeaker foamed paper pot, which is prepared by the following method: (1) 50 parts of bleached kraft pulp is added to a beater for beating, and when the beating degree reaches 30°SR, 8 parts of para-aramid fiber is added, and the beating is continued for 30 min to make the pulp and para-aramid fiber fully mixed. After filtration, a pulp with a beating degree of 30°SR is obtained. 3 parts of quaternary ammonium cationic starch is mixed with 300 parts of water, and heated at 90℃ for 15 min to obtain a cooked cationic starch; (2) The pulp obtained in step (1) is diluted with water to obtain a fiber suspension, and 40 parts of mica and 16 parts of azodicarbonamide are added while stirring, and then the cooked cationic starch obtained in step (1) is added, and the stirring is continued at a speed of 120 rpm for 15 min. After filtration, a paper pot wet embryo is obtained; (3) The paper pot wet embryo obtained in step (2) is placed in a high-temperature mold, and is pressed and dried at 220℃ for 20 s to control the thickness of the paper pot to 1 mm, and a paper pot blank is obtained; (4) removing the middle hole and the edge material of the paper cone blank obtained in step (3) by using a punching die to obtain the foamed paper cone for loudspeakers.

[0053] The novel mica foamed paper cone passes the waterproof test according to ISO 20653 and meets the IPX0 waterproof level.

[0054] Frequency response test: The sound pressure output capabilities of the paper cone loudspeakers of Example 1 and Comparative Example 1 at different frequencies were tested, and the frequency response graphs are shown in FIG. 2 and FIG. 3, respectively. Figure 5 As can be seen from the graphs, the sound pressure level of Example 1 is increased by more than 2 dB in the focused low frequency band (50-200 Hz), and the bass is full.

[0055] Total harmonic distortion test: The sound pressure output capabilities of the paper cone loudspeakers of Example 1 and Comparative Example 1 at different frequencies under the condition of 1 W / 1 m were tested, and the total harmonic distortion graphs are shown in FIG. 4 and FIG. 5, respectively. Figure 6 As can be seen from the graphs, the total harmonic distortion of Example 1 is ≤2% after 80 Hz, which is lower than that of Comparative Example 1 as a whole.

[0056] The above embodiments are the preferred implementation of the present application, in addition to this, the present application can be implemented in other ways, without departing from the concept of the present application, any obvious replacement within the protection scope of the present application.

Claims

1. A method for preparing a new type of mica foamed paper pot, characterized in that, It comprises the following steps: (S1), put mica powder and γ-aminopropyl triethoxysilane into a high-speed dispersion machine, add ethanol, and stir at 70-90℃ and 1300-1800r / min for 20-50min to form a mica pre-dispersion; (S2), add deionized water to nano-silica, and treat with an ultrasonic disperser for 15-25min to form a nano-silica suspension; (S3), put paper pulp and long-fiber cotton pulp into a hydraulic pulper, and disintegrate at 50-60℃ for 30-40min to obtain mixed paper pulp; (S4), add the mica pre-dispersion, nano-silica suspension, heat-expandable polymer foaming agent, and nano-modified lignin fiber to the mixed paper pulp in sequence, disperse at 600-1000r / min for 15-25min, and adjust the concentration to 6-7wt% to form a paper pulp suspension; (S5), use a papermaking process to make the paper pulp suspension on a forming mold, control the thickness of the formed paper basin to be 0.8-1.2mm, then dry at low temperature of 60-80℃ for 2-3h, and then dry at high temperature of 120-140℃ for 1h to form a gradient porous structure with a center foaming rate of 30-40% and an edge foaming rate of 10-15%, and obtain a dried paper basin; (S6), completely immerse the dried paper basin in a nano-silica and fluorine-nano-siloxane waterproof agent solution, soak at room temperature for 30-60min, and then dry at 80-100℃ for 20-30min to form a new mica foamed paper basin with a double waterproof structure.

2. The method for preparing a new mica foamed paper pot according to claim 1, characterized in that: In the step (S1), the addition amount of the γ-aminopropyl triethoxysilane accounts for 1%-2% of the mass of the mica powder, and the solid-liquid ratio of the mica pre-dispersion is 1:4-6; the mica powder is white mica powder with a particle size of 10-50μm.

3. The method of claim 1, wherein the method is characterized by: In the step (S2), the power of the ultrasonic disperser is 300W, and the nano-silica is a special silica sol for papermaking; the concentration of the nano-silica suspension is 4-6wt%.

4. The method for preparing a new mica foamed paper pot according to claim 1, characterized in that: In the steps (S3) and (S4), the weight amount of each raw material is as follows: paper pulp 50-60 parts, long-fiber cotton pulp 10-15 parts, mica pre-dispersion 120-150 parts, nano-silica suspension 10-25 parts, heat-expandable polymer foaming agent 5-10 parts, and nano-modified lignin fiber 1-3 parts.

5. The method of claim 1, wherein the method is characterized by: In the steps (S3) and (S4), the paper pulp is unbleached sulfite coniferous pulp; the heat-expandable polymer foaming agent is selected from type UM118, and has an average particle size of 20-35μm and an initial foaming temperature of 145-155℃.

6. The method of claim 1, wherein the method is characterized by: In the step (S4), the nano-modified lignin fiber is a nano-modified lignin fiber treated by plasma surface roughening and then pre-modified with silane coupling agent KH-550.

7. The method of claim 1, wherein the method is characterized by: In the step (S5), the center foaming pore size of the gradient porous structure is 15-20μm, and the edge foaming pore size of the gradient porous structure is 5-10μm.

8. The method of claim 1, wherein the method is characterized by: The concentration of the nanometer silicon dioxide and fluorine-nanosiloxane waterproof agent solution in the step (S6) is 15-20 wt%, and the fluorine-nanosiloxane waterproof agent is selected from YX-608; the double waterproof structure is composed of a fluorine hydrophobic layer on the surface and a nanometer siloxane permeation network in the inner layer.

9. A mica paper cone loudspeaker, characterized by: The dustproof cover is a light-weight ABS dustproof cover, and the hollow paper cone is prepared by the novel mica foamed paper cone preparation method according to any one of claims 1-8.

10. The mica paper cone loudspeaker of claim 9 wherein: The magnetic circuit system comprises a dust shield fixedly connected to the bottom of the cone frame, a magnet ring connected to the bottom of the dust shield, a T-shaped iron connected to the bottom of the magnet ring, a copper short-circuit ring sleeved on the outer periphery of the core column top of the T-shaped iron, an aluminum short-circuit ring integrally arranged on the outer periphery of the core column of the T-shaped iron, and a dust screen covered on the core column top of the T-shaped iron, wherein the T-shaped iron and the dust shield have an annular magnetic gap for the sound coil to extend into, the middle part of the core column of the T-shaped iron is provided with a ventilation through hole, and the top of the core column of the T-shaped iron is provided with a limiting groove communicating with the ventilation through hole and used for containing the dust screen.

Images