Basalt fiber felt frequency band sound absorption optimization treatment process
By heat-treating basalt fiber felt and adjusting its structure to change its sound absorption performance, the problem of insufficient sound absorption performance in the existing technology is solved, and the sound absorption performance is optimized and the application range is broadened.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2026-03-10
AI Technical Summary
Existing basalt fiber felts have insufficient sound absorption performance in different frequency bands, making it difficult to meet the needs of various applications. Furthermore, existing improvement methods are costly or affect chemical stability.
By heat-treating basalt fiber felt to adjust its structure and change its sound absorption performance, and by selecting an appropriate final heat treatment temperature range, a frequency band sound absorption optimization material with excellent sound absorption performance can be prepared.
It improves the sound absorption performance of basalt fiber felt, expands its application range, enhances its adaptability to different sound absorption environments, and has a simple process that does not affect the chemical stability of the material.
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Figure CN121629664A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of sound-absorbing material preparation and particularly relates to a frequency band sound-absorbing optimization treatment process for basalt fiber felt. BACKGROUND
[0002] Basalt fiber has good chemical stability, excellent mechanical properties, high temperature resistance and other excellent properties. It has very low moisture absorption capacity of only 0.2% to 0.3%, and the moisture absorption capacity does not change with time, which ensures its thermal stability, long service life and environmental compatibility during use. The sound-absorbing performance decreases less after being wetted, and it is widely used in aerospace, marine transportation, highway transportation, civil infrastructure and other fields. Basalt fiber felt is a collection of basalt fibers. It not only has the chemical stability of basalt fiber, but also has the porous structure characteristics, and is a sound-absorbing and heat-insulating material with excellent performance.
[0003] In recent years, with the progress of basalt fiber felt production technology at home and abroad, basalt fiber felt has been successfully developed. Ordinary basalt fiber has a coarse diameter, is brittle, and the fiber felt is thick and hard. In contrast, basalt fiber felt with a fiber diameter of less than 20 μm has excellent properties of thinness, lightness and softness, and is widely used in sound-absorbing and heat-insulating fields. The fibers in the basalt fiber felt are interlaced with each other, forming countless open porous structures that are interconnected, which are the main channels for the continuous propagation of sound waves. Compared with sound-absorbing materials with closed pores, the open porous structure can more effectively absorb sound energy, and the acoustic properties of basalt fiber felt are derived from this special structure.
[0004] The existing technology mainly focuses on exploring the improvement of different production processes of basalt fiber felt to improve the sound-absorbing performance of the felt. Specifically, first, the structure of the felt is changed. This method mainly adjusts the production and preparation method of the felt, which requires improvement of the production equipment and has a large cost. Second, the thickness of the felt is increased. This method has a good effect on improving the sound-absorbing performance, but it greatly increases the production cost and requires a large space to accommodate the thicker felt in actual application. Third, the felt is compounded with other materials. Since basalt fiber felt has stable chemical properties, compounding with other materials increases the production cost and also makes it difficult to guarantee the existing stable chemical properties, which directly affects the use range of the felt.
[0005] Compared with other sound absorption materials, although the basalt fiber felt has excellent sound absorption performance, it cannot completely achieve good sound absorption performance in full frequency band. In actual use process, the demand for sound absorption performance of basalt fiber felt is different for different use occasions. For example, the high frequency noise occasion has higher requirement for the sound absorption performance of the felt in high frequency band, and the low frequency noise occasion has higher requirement for the sound absorption performance of the felt in low frequency band. Therefore, designing a method for effectively selecting many excellent performances of basalt fiber and a practical and good sound absorption effect basalt fiber felt material which can effectively broaden the application of basalt fiber in the field of acoustics and increase the application scale has a positive effect. SUMMARY
[0006] The present application is based on the basalt fiber felt with the same structure parameters, in view of the current situation that a specific sound absorption curve and a relatively single application place, by using the bending deformation of basalt fiber at high temperature, so that the structure of the felt changes, and further affects the sound absorption performance, a basalt fiber felt frequency band sound absorption optimization sound absorption material is provided, which overcomes the shortcomings of the above-mentioned prior art. The heat treatment process of the present application is simple and feasible, which can further improve the sound absorption performance of the felt, so as to obtain a sound absorption material with more excellent sound absorption performance.
[0007] In order to achieve the above-mentioned purpose, the present application provides a frequency band sound absorption optimization treatment process of basalt fiber felt, which comprises the following steps: S1. Prepare basalt fiber felt; S2. Take several pieces of basalt fiber felt samples, set different final temperatures to heat treat the samples respectively, and the final temperature range is 300-800℃; S3. Test the sound absorption performance of the original sample and the several samples treated by heat respectively; S4. According to the results of the sound absorption performance test, analyze and compare the sound absorption performance, determine a sample with the best comprehensive sound absorption performance, and the final temperature corresponding to the sample is the heat treatment final temperature of the basalt fiber felt; S5. The heat treatment final temperature T is respectively increased and decreased by t℃ to obtain the heat treatment final temperature range of the basalt fiber felt, that is, [(T-t)~(T+t)]℃, wherein the value range of t is 5-15℃; the basalt fiber felt is treated by the heat treatment temperature rising program in the final temperature range, and a basalt fiber felt frequency band sound absorption optimization sound absorption material is obtained.
[0008] Preferably, in step S2, the temperature of the required equipment for heat treatment is not less than 1000℃, the temperature rising speed is 1-10℃ / min, the heating is stopped after the temperature rises to the final temperature, the sample is naturally cooled after the equipment is opened, and then taken out.
[0009] Preferably, the procedure further includes the following steps: S21. Take n portions of the basalt fiber felt sample, each 20*20cm in size, where n≥5, and label each of the n portions of the sample. S22. Select a value a as the final temperature of one of the samples, and a≤[800-b(n-1)]℃, where b is the temperature difference between the two consecutively set final temperatures of the samples; S23. Using the value a as the starting temperature of the final temperature of the n samples, the remaining (n-1) samples are respectively set with a temperature difference b corresponding to (n-1) continuously increasing different final temperatures; S24. Heat-treat each of the n samples at the corresponding final temperature.
[0010] Preferably, the value a is a multiple of 10, and the temperature difference b = 50℃.
[0011] Preferably, the equipment can be a muffle furnace. During the heat treatment, a three-layer high-temperature resistant support is provided inside the muffle furnace. The sample is placed in the middle layer for heating, and the support can withstand the highest temperature of the controllable temperature.
[0012] Preferably, in step S3, the sound absorption performance test step is as follows: S31. Test sound absorption performance; S32. Plot the sound absorption curve and calculate the average sound absorption coefficient.
[0013] Preferably, in step S5, t = 10°C.
[0014] On the other hand, the present invention also provides a sound-absorbing material prepared by a frequency band sound absorption optimization process of basalt fiber felt, wherein the fiber diameter of the sound-absorbing material is less than 20 μm and the thickness is less than 5 cm; the sound absorption performance of the sound-absorbing material at a selected frequency band is improved by no less than 10% after a heat treatment heating process.
[0015] The beneficial technical effects obtained by this invention are as follows: This invention is based on basalt fiber felt and uses a simple heat treatment process to obtain different sound absorption curves, which increases the adaptability of basalt fiber felt to different sound absorption environments and further expands the application range of basalt fiber felt. Attached Figure Description
[0016] Figure 1 This is a flowchart illustrating the preparation process of a frequency band sound-absorbing material optimized based on basalt fiber felt according to the present invention. Figure 2 This is a sound absorption curve diagram of Embodiment 1 of the present invention; Figure 3This is a sound absorption curve diagram of Embodiment 2 of the present invention; Figure 4 This is a sound absorption curve diagram of Embodiment 3 of the present invention. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some preferred embodiments of this application, but not all embodiments. In addition, for clarity and brevity, descriptions of known functions and structures are omitted in the embodiments.
[0018] In this article, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, B exists alone, and A and B exist simultaneously. In this article, the term " / and" describes another type of relationship between related objects, indicating that two relationships can exist. For example, A / and B can mean: A exists alone, and A and B exist alone.
[0019] (a) Basalt fiber felt Basalt fiber felt is a substrate material for sound-absorbing materials with optimized frequency band sound absorption based on basalt fiber felt. Generally, the diameter of the basalt fibers used in the sound-absorbing material is less than 20μm; the thickness of the basalt fiber felt is generally no more than 5 cm, and the thinnest basalt fiber felt that can be formed can be about 5 mm; the basis weight of the felt is usually between 50-300 g / m³. 2 Between; the pore size of felt is usually expressed as the average pore size, which is a specific value. Under current production technology, the average pore size is usually 10-30μm.
[0020] The fibers in basalt fiber felt are relatively fine. After heat treatment, the fibers undergo twisting, deformation, and displacement, causing changes in the felt structure. These changes in the felt structure at high temperatures directly affect the sound wave propagation path and sound energy dissipation within the felt, ultimately impacting its sound absorption performance. Different final heat treatment temperatures correspond to different sound absorption curves, meaning that the sound absorption coefficient varies for each frequency band.
[0021] (ii) Final heat treatment temperature The sound absorption performance requirements of basalt fiber felt vary depending on the application. Appropriate heat treatment final temperature can effectively improve the adaptability of basalt fiber felt to different sound absorption environments, and is key to preparing basalt fiber felt sound-absorbing materials with optimized frequency band absorption.
[0022] Basalt fiber felt, as a porous sound-absorbing material, possesses a unique sound absorption curve: a high sound absorption coefficient in the mid-to-high frequency range and a low sound absorption coefficient in the mid-to-low frequency range. After heat treatment, the felt's structure changes, thus altering its sound absorption performance and corresponding to a specific sound absorption curve. In other words, a specific final temperature corresponds to a specific felt structure, which in turn corresponds to a specific sound absorption coefficient curve, causing the sound absorption coefficient to vary across different frequency bands.
[0023] This invention defines the final temperature as follows: Final temperature: The final temperature is defined as the final temperature corresponding to the heating program. That is, it refers to the final temperature reached by a sample after a specific heating program from the initial temperature during heat treatment. In addition, the corresponding expression is the starting temperature of the heating program - the final temperature.
[0024] Heat treatment heating program: refers to the process of heating a sample from the initial temperature to a specified temperature (final temperature) according to a certain program.
[0025] Final heat treatment temperature: This final heat treatment temperature is defined as the most suitable final temperature selected based on the performance of the felt after multiple final temperature heat treatments for a certain sample. In other words, it refers to the final temperature at which the sample with the best overall sound absorption performance is finally determined after more than five final temperature treatments for the same type of basalt fiber felt.
[0026] Heat treatment final temperature range: The heat treatment final temperature range is defined by a specific value above or below the heat treatment final temperature, which is generally selected as ±10℃.
[0027] Heat treatment temperature range: Generally, the temperature from which the structural properties of the felt begin to change after heat treatment to the temperature at which the felt is destroyed is called the heat treatment temperature range. In this invention, when heat treating the felt, more than five final temperatures are typically selected. The selection principle is generally within the temperature range of "the temperature at which the structural properties of the felt begin to change to the temperature close to the temperature at which the felt is destroyed." For basalt fiber felt materials, the heat treatment temperature range is generally 300–800℃. For different types of basalt fiber felt, the actual heat treatment temperature range is generally different. For example, in the embodiments of the invention, final temperatures of 400℃, 450℃, 500℃, 550℃, and 600℃ are selected. Therefore, 400–600℃ can be considered the heat treatment temperature range for the basalt fiber felt corresponding to this embodiment.
[0028] If the heat treatment temperature is set too low, the basalt fiber will not easily deform, failing to alter the felt's structure and thus preventing the adjustment of sound absorption performance. Conversely, if the temperature is set too high, the basalt fiber felt will easily melt into a hard, structurally imperfect object, lacking sound absorption properties. Due to the unique nature of the production process, the internal composition and fiber diameter of each type of basalt fiber felt, and even each batch, are not entirely identical, resulting in different sound absorption curves at different final heat treatment temperatures. Therefore, determining the appropriate final heat treatment temperature for basalt fiber felt can effectively improve its sound absorption performance.
[0029] (III) Basalt fiber felt frequency band sound absorption optimization sound absorption material Basalt fiber felt frequency band sound absorption optimization sound absorption material is made of basalt fiber felt through heat treatment. It utilizes the deformation characteristics of basalt fiber at high temperature to change the structure of the felt and adjust the sound absorption performance of the felt in different frequency bands.
[0030] The sound absorption performance of the basalt fiber felt frequency band sound absorption optimization material described in this application is characterized by the sound absorption coefficient, including the average sound absorption coefficient and the sound absorption curve. The average sound absorption coefficient is a specific value; the sound absorption curve can be understood as a curve connecting the sound absorption coefficients corresponding to each frequency. However, in actual testing, the sound absorption coefficient is not collected for each frequency. The level of the sound absorption curve varies across different frequency bands, generally not to a specific value; a higher sound absorption curve indicates higher sound absorption performance in that frequency band, and vice versa.
[0031] The sound absorption coefficient is typically determined using the transfer function method. This involves testing the transient sound pressure signal between two points in a standing wave sound field and then using Fourier transform analysis to derive the transfer function. Based on the principle of sound wave superposition, the reflection coefficient γ is calculated, and the perpendicular incident sound absorption coefficient is then: .
[0032] Specialized instruments are used for testing sound absorption performance, such as the dual-microphone impedance tube system manufactured by Beijing Shengwang Acoustic & Electrical Technology Co., Ltd., and corresponding data processing software such as VA-Lab4 1MP-AT software. The sound absorption curve is obtained through data fitting.
[0033] A suitable final heat treatment temperature can improve the overall sound absorption performance of the felt across the entire frequency range, with an overall improvement of over 10%. The degree of improvement will vary across different frequency ranges, and the appropriate final heat treatment temperature can be selected based on the specific application.
[0034] While improving sound absorption performance, the change in felt structure leads to a slight decrease in the strength of basalt fiber felt. However, when basalt fiber felt is used as a sound-absorbing material, it is typically fixed to the surface of objects such as cabins and buildings, so this change in strength does not affect its use as a sound-absorbing material.
[0035] (III) Treatment process for basalt fiber felt frequency band sound absorption optimization sound absorption materials A process for optimizing the frequency band sound absorption of basalt fiber felt includes the following steps: 1. Basalt fiber felt sample Prepare n identical basalt fiber felt samples, each 20*20cm in size, where n≥5. Mark each of the n samples. Select different final temperatures for the n samples within a final temperature range of 300~800℃, using the following method: 1) Select a value a as the final temperature of one of the n samples, requiring a≤[800-b(n-1)]℃, where b is the temperature difference between the final temperatures of two consecutively set samples; 2) Using the value a as the starting temperature, set the final temperature of (n-1) different values with a temperature difference b for the remaining (n-1) samples respectively.
[0036] The number of samples is typically selected based on requirements, with a minimum of 5 samples. Within the temperature range of 300~800℃, samples are heat-treated using the same heating program and the same number of final temperatures as the sample portions. Value 'a' represents the starting temperature of the selected final temperature range, and a temperature difference of value 'b' needs to be reserved for the remaining (n-1) samples. Temperature difference 'b' is usually a fixed value set according to the situation and should not be too large or too small. If the temperature difference is too small, the change in sound absorption performance will not be obvious; if it is too large, on the one hand, it will not reflect the pattern of sound absorption curve changes; on the other hand, it will cause the maximum final temperature of the sample to exceed the melting point of basalt fiber, at which point the felt will break, rendering it unusable and meaningless.
[0037] For example, if there are 5 samples, and the initial temperature is set to a=300℃ and the temperature difference to b=50℃, then the final temperatures of the remaining 4 samples are set to 350℃, 400℃, 450℃ and 500℃ respectively.
[0038] 2. Sample heat treatment The n samples were heat-treated at their respective final temperatures. A muffle furnace was selected as the heat treatment equipment. During heat treatment, a three-layer high-temperature resistant support was installed inside the muffle furnace. The sample was placed in the middle layer for heating to ensure uniform heating of the felt. The support was required to withstand a maximum controllable temperature, i.e., temperatures exceeding 1000℃. No vacuuming or inert gas introduction was required during muffle furnace heat treatment.
[0039] Heat treatment heating process: Start from room temperature, increase the temperature by 1-10°C per minute, stop heating after reaching the final temperature, keep the temperature for 20-60 minutes, open the equipment and let the sample cool naturally to room temperature before taking it out.
[0040] 3. Sound absorption performance test; For the above n heat-treated samples and the original sample, the sound absorption performance was tested, sound absorption curves were plotted, and the average sound absorption coefficient was calculated. The sound absorption performance of the felt was comprehensively evaluated. The steps are as follows: 1) Test sound absorption performance; Test instruments: Dual microphone impedance tube system, VA-Lab4 1MP-AT software, Beijing Shengwang Acoustics & Electronics Technology Co., Ltd.; The evaluation standard for sound absorption performance adopts GB / T 18696.2 2002 Measurement of sound absorption coefficient and acoustic impedance in acoustic impedance tubes - Part 2: Transfer function method; 2) Plot the sound absorption curve and calculate the average sound absorption coefficient.
[0041] The sound absorption testing system can directly export sound absorption curves and corresponding data. When exporting test results, you can choose to output them at 1 / 3 octave, 1 / 6 octave, or 1 / 12 octave, etc.
[0042] Using software tools such as Origin and Excel, the sound absorption curves of the same sample after heat treatment at different final temperatures were plotted with frequency as the horizontal axis and sound absorption coefficient as the vertical axis.
[0043] The average sound absorption coefficient is the arithmetic mean of the sound absorption coefficients at all frequencies across the entire frequency band. The selected frequencies are spaced 2 Hz apart, i.e., 100 Hz, 102 Hz, 104 Hz, ..., 6300 Hz.
[0044] 4. Sound absorption performance analysis and comparison Based on the sound absorption performance test results of the original sample and n heat-treated samples, sound absorption performance analysis and comparison are performed. Specifically, the sound absorption performance curves mentioned above can be compared and analyzed to determine the changes in the sound absorption coefficient of the samples at different final temperatures compared to the original sample across the entire frequency range or at a specific frequency range.
[0045] 5. Basalt fiber felt as a sound-absorbing material with optimized frequency band sound absorption. Based on the different sound absorption performance requirements of the application scenario, the sound absorption curve of the heat-treated sample is selected. The final temperature corresponding to the sound absorption curve is the final heat treatment temperature T. The heat-treated sample is the sound-absorbing material with optimized sound absorption in the basalt fiber felt frequency band.
[0046] The temperature range obtained by adjusting the final heat treatment temperature T by t℃ above and below the final heat treatment temperature, i.e., (Tt, T+t)℃, is the final heat treatment temperature range of basalt fiber felt, where the value of t ranges from 5 to 15℃, preferably 10℃. By treating the basalt fiber felt with the above heat treatment method within the temperature range of (Tt, T+t)℃, a sound-absorbing material with optimized sound absorption in the basalt fiber felt frequency band can be obtained. Example 1
[0047] Basalt fiber felt structural parameters: fiber diameter 11.93μm, felt thickness 12.12mm.
[0048] The basalt fiber felt was cut into 5 samples, each measuring 20*20 cm.
[0049] To ensure that the basalt fiber felt is heated evenly, a three-layer support is installed inside the muffle furnace, and a high-temperature resistant plate (resistant to temperatures above 1000℃) is placed on the middle layer support. The felt is then placed on the high-temperature resistant plate in the middle layer for heating.
[0050] The final temperatures of the heating programs for the five samples were 350℃, 400℃, 450℃, 500℃, and 550℃, respectively.
[0051] The heating procedure is as follows: start from room temperature, increase the temperature by 5°C per minute, and after reaching the final temperature of 400°C, hold the temperature for 30 minutes. Then open the muffle furnace and wait for the sample to cool to room temperature before taking out the felt.
[0052] The sound absorption performance of the heat-treated sample and the original sample was tested, and sound absorption curves were plotted and compared. The results showed that the sound absorption curve of the sample with a final heating temperature of 400℃ significantly improved in the frequency range above 2500Hz, both in terms of the sound absorption curve and the sound absorption coefficient. Therefore, using 400℃ as the final heat treatment temperature for this basalt fiber felt, a sound-absorbing material with optimized sound absorption in the basalt fiber felt frequency range was successfully prepared. The sound absorption curves of the original sample and the felt heat-treated at 400℃ are shown in the attached figure. Figure 2 .
[0053] Therefore, for this basalt fiber felt, the final heat treatment temperature T is 400℃, and t=10℃ is taken. Thus, the final heat treatment temperature range is (400-10, 400+10)℃, that is, 390℃~410℃. This can produce basalt fiber felt sound-absorbing material with significantly improved sound absorption performance in the frequency band above 2500HZ. Example 2
[0054] Basalt fiber felt structural parameters: fiber diameter 12.2μm, felt thickness 13.2mm.
[0055] The basalt fiber felt was cut into 5 samples, each measuring 20*20 cm.
[0056] To ensure that the basalt fiber felt is heated evenly, a three-layer support is installed inside the muffle furnace, and a high-temperature resistant plate (resistant to temperatures above 1000℃) is placed on the middle layer support. The felt is then placed on the high-temperature resistant plate in the middle layer for heating.
[0057] The final temperatures of the heating programs for the five samples were 400℃, 450℃, 500℃, 550℃, and 600℃, respectively.
[0058] The heating procedure is as follows: start from room temperature, increase the temperature by 8°C per minute, hold the temperature for 40 minutes after reaching the final temperature, then open the muffle furnace and remove the felt after the sample has cooled to room temperature.
[0059] The sound absorption performance of the heat-treated sample and the original sample was tested, and sound absorption curves were plotted and compared. The results showed that the sound absorption curve of the sample with a final heating temperature of 500℃ significantly improved across the entire frequency range, both in terms of the sound absorption curve and the sound absorption coefficient. Therefore, using 500℃ as the final heat treatment temperature for basalt fiber felt, a sound-absorbing material with optimized sound absorption across the basalt fiber felt frequency range was successfully prepared. The sound absorption curves of the original sample and the felt heat-treated at 500℃ are shown in the appendix. Figure 3 .
[0060] Therefore, for this basalt fiber felt, the final heat treatment temperature T is 500℃, and t=10℃ is taken. Thus, the final heat treatment temperature range is (500-10, 500+10)℃, that is, 490℃~510℃. This can produce a basalt fiber felt sound-absorbing material with optimized sound absorption performance across the entire frequency band. Example 3
[0061] Basalt fiber felt structural parameters: fiber diameter 13.2μm, felt thickness 14.2mm.
[0062] The basalt fiber felt was cut into 5 samples, each measuring 20*20 cm.
[0063] To ensure that the basalt fiber felt is heated evenly, a three-layer support is installed inside the muffle furnace, and a high-temperature resistant plate (resistant to temperatures above 1000℃) is placed on the middle layer support. The felt is then placed on the high-temperature resistant plate in the middle layer for heating.
[0064] The final temperatures of the heating programs for the five samples were 400℃, 450℃, 500℃, 550℃, and 600℃, respectively.
[0065] The heating procedure is as follows: start from room temperature, increase the temperature by 10°C per minute, and after reaching the final temperature, hold the temperature for 60 minutes. Then open the muffle furnace and remove the felt after the sample has cooled to room temperature.
[0066] The sound absorption performance of the heat-treated sample and the original sample was tested, and sound absorption curves were plotted and compared. The results showed that the sound absorption coefficient of the sample with a final heating temperature of 450℃ was improved across the entire frequency range, with particularly significant improvements in the 100-2500Hz frequency band. Therefore, using 450℃ as the final heat treatment temperature for basalt fiber felt, a sound-absorbing material with optimized frequency band sound absorption was successfully prepared. The sound absorption curves of the original sample and the 450℃ heat-treated felt are shown in the appendix. Figure 4 .
[0067] Therefore, for this basalt fiber felt, the final heat treatment temperature T is 450℃, and t=10℃ is taken. Thus, the final heat treatment temperature range is (450-10, 450+10)℃, that is, 440℃~460℃. This can produce basalt fiber felt sound-absorbing material with significantly improved sound absorption performance across the entire frequency band, especially in the 100-2500HZ frequency band.
[0068] Table 1. Test results of average sound absorption coefficient in embodiments of the present invention (the percentage increase in average sound absorption coefficient is in parentheses).
[0069] Note: Sound absorption instruments can measure the sound absorption coefficient in the frequency range of 100-6300 Hz. Based on the sound absorption characteristics of basalt fiber felt, the sound absorption performance of two sub-bands and the full frequency band is comprehensively analyzed. The corresponding frequency bands are 100-2500 Hz (mid-low frequency band), 2500 Hz-6300 Hz (high frequency band), and 100-6300 Hz (full frequency band).
[0070] It is evident that the sound absorption performance of basalt fiber felt is improved after heat treatment, with varying degrees of improvement across different frequency bands. For instance, the basalt fiber felt of Example 1 exhibits significantly optimized sound absorption performance in the 2500-6300Hz frequency band, while Examples 2 and 3 show significant improvements in sound absorption performance across the entire frequency band. This invention, through a simple heat treatment process, produces a sound-absorbing material with optimized sound absorption across multiple frequency bands, increasing its adaptability to various sound absorption environments and further expanding its application scope.
[0071] The embodiments described above are merely illustrative of several implementations of the present invention, designed to facilitate a detailed understanding of the technical solutions of the present invention, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided by the present invention through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this invention patent should be determined by the content of the appended claims, and the specification and drawings can be used to interpret the content of the claims.
Claims
1. A process for optimizing the band absorption of a basalt fiber mat, characterized by: The processing process comprises the following steps: S1. Preparing a basalt fiber felt; S2. Taking several pieces of the basalt fiber felt sample, setting different final temperatures to heat treat the sample respectively, and the final temperature range is 300-800℃; S3. Testing the sound absorption performance of the original sample and the several samples respectively after heat treatment; S4. According to the results of the sound absorption performance test, analyzing and comparing the sound absorption performance to determine a sample with the best comprehensive sound absorption performance, and the final temperature corresponding to the sample is the heat treatment final temperature T of the basalt fiber felt; S5. The heat treatment final temperature T is increased and decreased by t℃ respectively to obtain the heat treatment final temperature range of the basalt fiber felt, that is, [(T-t)~(T+t)]℃, wherein the value range of t is 5-15℃; the basalt fiber felt is treated with the heat treatment temperature rising program in the final temperature range to obtain a basalt fiber felt frequency band sound absorption optimization material.
2. The process for optimizing the acoustic absorption of a frequency band of a basalt fiber mat according to claim 1, characterized in that: In step S2, the required equipment for heat treatment has a controllable temperature not lower than 1000℃, the temperature rising speed is 1-10℃ / min, the heating is stopped after the temperature rises to the final temperature, the sample is kept warm for 20-60min, and the sample is taken out after the equipment is opened and the sample is naturally cooled.
3. The process for optimizing the acoustic absorption of a frequency band of a basalt fiber mat according to claim 2, characterized in that: Further comprising the following steps: S21. Taking n portions of the basalt fiber felt sample, with a size of 20*20cm, wherein n≥5, and marking the n portions of the sample respectively; S22. Selecting a numerical value a as the final temperature of one of the samples, and a≤[800-b(n-1)]℃, wherein b is the temperature difference between two consecutive final temperatures of the samples; S23. Taking the numerical value a as the starting temperature of the final temperature of the n samples, and setting (n-1) consecutive increasing final temperatures with different numerical values for the remaining (n-1) samples respectively with a temperature difference b; S24. Heat treating the n portions of the sample respectively with the corresponding final temperature.
4. The process for optimizing the acoustic absorption of a frequency band of a basalt fiber mat according to claim 3, characterized in that: The numerical value a is a multiple of 10, and the temperature difference b=50℃.
5. The process for optimizing the acoustic absorption of a frequency band of a basalt fiber mat according to claim 3, characterized in that: The equipment can be a muffle furnace, and a three-layer high-temperature resistant support is arranged in the muffle furnace during the heat treatment, the sample is heated in the middle layer, and the support can withstand the highest temperature of the controllable temperature.
6. The process for optimizing the acoustic absorption of a frequency band of a basalt fiber mat according to claim 1, characterized in that: In step S3, the sound absorption performance test comprises the following steps: S31. Testing the sound absorption performance; S32. Drawing a sound absorption curve and calculating the average sound absorption coefficient.
7. A process for optimizing the acoustic absorption of a frequency band of a basalt fiber mat according to claims 1-6, characterized in that: In step S5, t=10℃.
8. A sound absorption material prepared according to the frequency band sound absorption optimization processing process of the basalt fiber felt of any one of claims 1-7, wherein the fiber diameter of the sound absorption material is less than 20μm, the felt thickness is less than 5cm; and the sound absorption performance of the sound absorption material is improved by not less than 10% in the selected frequency band after the heat treatment temperature rising program.