Porous composite sound-absorbing material, method for preparing the same
11837210 · 2023-12-05
Assignee
Inventors
Cpc classification
International classification
Abstract
A porous composite sound-absorbing material and a method for preparing the same are provided. The porous composite sound-absorbing material includes activated carbon cotton felt, zeolite particles, and an adhesive. The activated carbon cotton felt can bond the zeolite particles to fiber surfaces thereof by means of the adhesive, so that the zeolite particles are evenly dispersed and fixed and achieve optimal sound absorption performance. Meanwhile, a large number of micro-pore structures on surfaces thereof can act synergistically with the zeolite particles, so that the porous composite sound-absorbing material has significantly better sound absorption performance than the two and has extremely high cost performance. During the preparation process, the activated carbon cotton felt after treatments, is successfully compounded with the zeolite particles with more excellent sound absorption performance, so that the sound absorption performance is significantly improved and the cost performance is extremely high.
Claims
1. A porous composite sound-absorbing material, comprising activated carbon cotton felt, zeolite particles, and an adhesive; wherein the activated carbon cotton felt serves as a framework material, and the zeolite particles are bonded to a fiber surface of the activated carbon cotton felt by means of the adhesive.
2. The porous composite sound-absorbing material as described in claim 1, wherein macro-pores with pore sizes ranging from 1 μm to 1000 μm exist among activated carbon fibers of the activated carbon cotton felt, and surfaces of the activated carbon fibers have a large number of micro-pores with pore sizes less than 2 nm, the micro-pores accounting for a proportion of 5% to 95%.
3. The porous composite sound-absorbing material as described in claim 1, wherein a particle size of the zeolite particles ranges from 50 nm to 1 mm.
4. The porous composite sound-absorbing material as described in claim 1, wherein, the activated carbon cotton felt accounts for 5% to 90% by mass of the porous composite sound-absorbing material, the zeolite particles account for 1% to 85% by mass of the porous composite sound-absorbing material, and the adhesive accounts for 1% to 30% by mass of the porous composite sound-absorbing material.
5. The porous composite sound-absorbing material as described in claim 1, wherein the adhesive is one or more of an acrylic adhesive, a styrene butadiene adhesive, a polyurethane adhesive, an epoxy adhesive, and a silicone adhesive.
6. A method for preparing a porous composite sound-absorbing material as described in claim 1, the method comprising following steps: S1: surface treatment of activated carbon cotton felt surface-treating the activated carbon cotton felt to improve sound absorption performance and increase wettability with a sound-absorbing stock solution; S2: preparation of the sound-absorbing stock solution blending the zeolite particles, the adhesive, a dispersing auxiliary agent, a foaming agent, and a dispersant to obtain the sound-absorbing stock solution; S3: impregnation impregnating the activated carbon cotton felt treated in step S1 with the sound-absorbing stock solution obtained in step S2 to obtain a zeolite-activated carbon cotton felt composite material; S4: setting quick-freezing the zeolite-activated carbon cotton felt composite material obtained in step S3 of impregnation, so as to set the zeolite-activated carbon cotton felt composite material; S5: removal of the dispersant removing, by freeze drying, the dispersant contained in the zeolite-activated carbon cotton felt composite material set in step S4; S6: curing baking the zeolite-activated carbon cotton felt composite material, from which the dispersant is removed in step S5, under a condition that the adhesive is curable, so as to cure the adhesive contained in the zeolite-activated carbon cotton felt composite material; S7: cleaning ultrasonically cleaning the zeolite-activated carbon cotton felt composite material by water several times to remove residual dispersing auxiliary agent, foaming agent and unbonded zeolite particles; and S8: drying drying moisture to obtain the porous composite sound-absorbing material.
7. The method as described in claim 6, wherein the activated carbon cotton felt is surface-treated in step S1 in one or more manners selected from plasma treatment, corona treatment, oxidation treatment, reduction treatment, acid treatment, alkali treatment, surfactant solution soaking, and solvent soaking.
8. The method as described in claim 6, wherein, in step S2, 100 parts of the zeolite particles, 1 to 200 parts of the adhesive, 1 to 50 parts of the dispersing auxiliary agent, 1 to 50 parts of the foaming agent, and 50 to 9900 parts of the dispersant are blended to obtain the sound-absorbing stock solution.
9. The method as described in claim 6, wherein the foaming agent is one or more of a physically volatile foaming agent, a thermal decomposition foaming agent, and a two-component reactive foaming agent.
10. The method as described in claim 6, wherein the dispersing auxiliary agent is one or more of a cationic surfactant, an anionic surfactant, a zwitterionic surfactant, and a nonionic surfactant.
11. A speaker, comprising a rear cavity, wherein the rear cavity comprises a porous composite sound-absorbing material, wherein the porous composite sound-absorbing material comprises activated carbon cotton felt, zeolite particles, and an adhesive; wherein the activated carbon cotton felt serves as a framework material, and the zeolite particles are bonded to a fiber surface of the activated carbon cotton felt by means of the adhesive.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2) 1: activated carbon fiber of activated carbon cotton felt in the porous composite sound-absorbing material according to the present disclosure; 2: zeolite particle.
(3)
(4)
DESCRIPTION OF EMBODIMENTS
(5) Activated carbon cotton felt is used as a framework material, and zeolite particles are bonded to a fiber surface of the activated carbon cotton felt by means of an adhesive and undergo quick-freezing setting, freeze drying, and high-temperature treatment. The present disclosure prepares a new porous composite sound-absorbing material, whose schematic structural diagram is shown in
(6) The activated carbon cotton felt used in the present disclosure has a large number of micro-pores, whose sound absorption performance is obviously better than that of sound-absorbing cotton and sound-absorbing fibers with only macro-pore structures. Moreover, after modification of zeolite with better sound absorption performance and in combination with the quick-freezing setting technology that can significantly improve uniformity of distribution of zeolite, the present disclosure greatly reduces the costs and solves the technical problem of inconvenient use of granular materials such as zeolite. The porous composite sound-absorbing material according to the present disclosure also further improves the sound absorption performance of the activated carbon cotton felt, so that low-frequency performance thereof can be significantly improved after a rear cavity of a speaker is filled with the porous composite sound-absorbing material according to the present disclosure.
(7) Further descriptions are provided below through embodiments. It should be understood that specific embodiments described herein are intended only to interpret the present disclosure but not to limit the present disclosure.
PREPARATION EXAMPLE
Example 1
(8) Activated carbon cotton felt with macro-pores having pore sizes ranging from 1 μm to 1000 μm and micro-pores having pore sizes below 2 nm was used. A specific surface area of the activated carbon cotton felt was 1300 m.sup.2/g, and the micro-pores accounted for a proportion of 80%.
(9) The activated carbon cotton felt was cut according to a shape of a rear cavity of a speaker. By mass, there were 30 parts of the activated carbon cotton felt after cutting, which were soaked in ethanol for 12 h and then baked in an air dry oven at 110° C. for 2 h to remove the ethanol.
(10) The activated carbon cotton felt was baked in the air dry oven at 200° C. for 2 h and underwent oxidization treatment. The front and the side of the activated carbon cotton felt were scanned using an SEM respectively, to obtain an SEM image shown in
(11) By mass, 100 parts of zeolite particles having pore sizes ranging from 0.2 μm to 20 μm, 20 parts of a styrene butadiene adhesive, 10 parts of sodium lauryl sulfate, 40 parts of potassium persulfate, and 1800 parts of water were evenly mixed by a magnetic stirrer to obtain the sound-absorbing stock solution, ready for use.
(12) The activated carbon cotton felt after oxidization treatment was placed in the sound-absorbing stock solution to undergo ultrasound for 1 h, the soaked activated carbon cotton felt was then taken out, excess sound-absorbing stock solution on its surface was gently and quickly wiped off using filter paper, and then the activated carbon cotton felt was quickly frozen and set through a low-temperature environment (either by using a refrigeration device or a refrigerant).
(13) After being quickly frozen and set, the activated carbon cotton felt was frozen and dried using a freeze dryer, so as to completely remove moisture in the material.
(14) After being frozen and dried, the activated carbon cotton felt was baked for 2 h in the oven at a temperature of 110° C. to cause the styrene butadiene adhesive to be completely cured.
(15) The activated carbon cotton felt was cleaned 5 times with deionized water by using an ultrasonic cleaner, which was cleaned for 10 min each time, to remove residual foaming agent and surfactant and unbonded zeolite particles, and was baked for 1 h in the oven at the temperature of 110° C. to obtain a blocky porous composite sound-absorbing material.
(16) The front and the side of the obtained porous composite sound-absorbing material were scanned using an SEM respectively, to obtain an SEM image shown in
Example 2
(17) The activated carbon cotton felt used in this embodiment was completely the same as that in Example 1.
(18) The activated carbon cotton felt was cut according to a shape of a rear cavity of a speaker. By mass, there were 30 parts of the activated carbon cotton felt after cutting, which were soaked in ethanol for 12 h and then baked in an oven at 110° C. for 2 h to remove the ethanol.
(19) The activated carbon cotton felt was baked in the air dry oven at 200° C. for 2 h and underwent oxidization treatment.
(20) By mass, 100 parts of zeolite particles having pore sizes ranging from 0.2 μm to 20 μm, 10 parts of a silicone adhesive, 15 parts of sodium dodecyl benzene sulfonate, 20 parts of ammonium persulfate, and 550 parts of water were evenly mixed by a magnetic stirrer to obtain the sound-absorbing stock solution, ready for use.
(21) The activated carbon cotton felt after oxidization treatment was placed in the sound-absorbing stock solution to undergo ultrasound for 1 h, the soaked activated carbon cotton felt was then taken out, excess sound-absorbing stock solution on its surface was gently and quickly wiped off using filter paper, and then the activated carbon cotton felt was quickly frozen and set through a low-temperature environment (either by using a refrigeration device or a refrigerant).
(22) After being quickly frozen and set, the activated carbon cotton felt was frozen and dried using a freeze dryer, so as to completely remove moisture in the material.
(23) After being frozen and dried, the activated carbon cotton felt was baked for 2 h in the oven at a temperature of 110° C. to cause the silicone adhesive to be completely cured.
(24) The activated carbon cotton felt was cleaned 5 times with deionized water by using an ultrasonic cleaner, which was cleaned for 10 min each time, to remove residual foaming agent and surfactant and unbonded zeolite particles, and was baked for 1 h in the oven at the temperature of 110° C. to obtain a blocky porous composite sound-absorbing material.
(25) The front and the side of the obtained porous composite sound-absorbing material were scanned using an SEM respectively, to obtain an SEM image (the SEM image was not shown) basically the same as the SEM image of the porous composite sound-absorbing material in Example 1, from which it can be obviously seen that the zeolite particles had been firmly bonded to a fiber surface of the activated carbon cotton felt. Refer to Table 1 for details of acoustic performance data thereof.
Example 3
(26) The activated carbon cotton felt used in this embodiment was completely the same as that in Example 1.
(27) The activated carbon cotton felt was cut according to a shape of a rear cavity of a speaker. By mass, there were 30 parts of the activated carbon cotton felt after cutting, which were soaked in ethanol for 12 h and then baked in an air dry oven at 110° C. for 2 h to remove the ethanol.
(28) The activated carbon cotton felt was baked in the air dry oven at 200° C. for 2 h and underwent oxidization treatment.
(29) By mass, 100 parts of zeolite particles having pore sizes ranging from 0.2 μm to 20 μm, 15 parts of an acrylic adhesive, 3 parts of sodium dodecyl benzene sulfonate, 7 parts of sodium bicarbonate, and 135 parts of water were evenly mixed by a magnetic stirrer to obtain the sound-absorbing stock solution, ready for use.
(30) The activated carbon cotton felt after oxidization treatment was placed in the sound-absorbing stock solution to undergo ultrasound for 1 h, the soaked activated carbon cotton felt was then taken out, excess sound-absorbing stock solution on its surface was gently and quickly wiped off using filter paper, and then the activated carbon cotton felt was quickly frozen and set through a low-temperature environment (either by using a refrigeration device or a refrigerant).
(31) After being quickly frozen and set, the activated carbon cotton felt was frozen and dried using a freeze dryer, so as to completely remove moisture in the material.
(32) After being frozen and dried, the activated carbon cotton felt was baked for 2 h in the oven at a temperature of 110° C. to cause the styrene butadiene adhesive to be completely cured.
(33) The activated carbon cotton felt was cleaned 5 times with deionized water by using an ultrasonic cleaner, which was cleaned for 10 min each time, to remove residual foaming agent and surfactant and unbonded zeolite particles, and was baked for 1 h in the oven at the temperature of 110° C. to obtain a blocky porous composite sound-absorbing material.
(34) The front and the side of the obtained porous composite sound-absorbing material were scanned using an SEM respectively, to obtain an SEM image (the SEM image was not shown) is basically the same as the SEM image of the porous composite sound-absorbing material in Example 1, from which it can be obviously seen that the zeolite particles had been firmly bonded to a fiber surface of the activated carbon cotton felt. Refer to Table 1 for details of acoustic performance data thereof.
(35) Measurement of Acoustic Performance
(36) According to a method for measuring a resonant frequency of a speaker, the porous composite sound-absorbing materials prepared in Example 1, Example 2, and Example 3 were respectively placed in a suitable tool, values of decline in a resonant frequency (F0) thereof were tested using an impedance analyzer, and dropping and breakage of the porous composite sound-absorbing materials were tested through a dropping test. F0 decline denotes a degree to which the resonant frequency moves to a low frequency. Generally, the greater the value of F0 decline, the better the low-frequency performance of the speaker.
(37) A volume of a tooling rear cavity of the speaker used in measurement of acoustic performance was 0.4 cubic centimeter (0.4 cc for short), and specific test results were shown in Table 1.
(38) TABLE-US-00001 TABLE 1 Test results of acoustic performance in examples F0 decline Dropping and Sample F0 (Hz) (Hz) breakage The rear cavity was not 1039 — — filled with any sound- absorbing material The rear cavity was filled 994 45 No breakage, and with sound-absorbing no powder dropping foam The rear cavity was filled 996 43 No breakage, and with sound-absorbing no powder dropping fibers The rear cavity was filled 925 114 No breakage, and with treated activated no powder dropping carbon cotton felt (a framework material with a large number of micro-pores in an example) The rear cavity was filled 801 238 No breakage, and with Bass powder no powder dropping The rear cavity was filled 877 162 No breakage, and with the porous composite slight powder sound-absorbing material in dropping Example 1 The rear cavity was filled 834 205 No breakage, and with the porous composite no powder dropping sound-absorbing material in Example 2 The rear cavity was filled 768 271 No breakage, and with the porous composite no powder dropping sound-absorbing material in Example 3
(39) It can be known according to the results in Table 1 that the activated carbon cotton felt (framework material) in the disclosure had more excellent sound absorption performance than the conventional framework materials (the sound-absorbing foam and the sound-absorbing fibers) due to presence of micro-pore structures. After the rear cavity of the tooling was filled with the porous composite sound-absorbing material according to the present disclosure, the F0 decline of the speaker was no less than 160 Hz. After the rear cavity was filled with the porous composite sound-absorbing material according to Example 3, the F0 decline of the speaker was 271 Hz, and its performance was significantly better than that of the activated carbon cotton felt and Bass particles (current sound-absorbing materials with the best speaker commercial use effect), indicating that the low-frequency performance was significantly improved. Meanwhile, the price of the material of the present disclosure was greatly reduced compared with Bass, and thus has extremely high cost performance. In addition, slight powder dropping occurred in the speaker made of the porous composite sound-absorbing material in Example 1, while no powder dropping occurred in the speakers made of the porous composite sound-absorbing material in Example 2 and the porous composite sound-absorbing material in Example 3.
(40) The objectives, technical solutions, and beneficial effects of the present disclosure are described in detail above. It should be understood that the above descriptions are merely embodiments and specific examples of the present disclosure, and are not intended to limit the protection scope of the present disclosure. Any modification, equivalent replacement, improvement, and the like made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure.