Composite sound-absorbing cloth, manufacturing process and application

Abstract

The application discloses a composite sound-absorbing cloth, a manufacturing process and application. The first fiber cloth layer, the second fiber cloth layer, the third fiber cloth layer and the fourth fiber cloth layer of the composite sound-absorbing cloth are overlapped and bonded through a glue point layer. The composite sound-absorbing cloth, the manufacturing process and the application introduce the factor of the material density of the fiber cloth layer and limit the thickness of each fiber cloth layer, so that the difference in the area density of the fiber cloth layer can be reflected in the difference in acoustics. The fiber cloth layers with different area densities can produce superior sound-absorbing effects at different frequencies, respectively, and form interfaces with different structures between the fiber cloth layers with different area densities, thereby forming a dissipating effect. The glue point layer bonds the adjacent fiber cloth layers, so that the bonding effect is high quality, and the pores of the fiber cloth layers are retained at the same time, thereby greatly improving the acoustic effect of the composite sound-absorbing cloth.

Description

Technical Field

[0001] This invention relates to the field of sound-absorbing fabrics, and in particular to a composite sound-absorbing fabric, its manufacturing process, and its application. Background Technology

[0002] As the requirements for acoustic environments in daily life and work continue to increase, the demand for noise-absorbing materials is constantly growing. In scenarios where redesign and construction are inconvenient, there are applications for sound-absorbing materials that are easy to install and offer superior acoustic performance. Traditional porous sound-absorbing materials are ineffective against low-frequency noise, and thin, lightweight materials with excellent low-frequency broadband sound absorption are even more difficult to obtain. Increasing the overall thickness of the sound-absorbing material can improve acoustic performance across the entire frequency range; however, this not only leads to a dramatic increase in material thickness, but the contribution of increased thickness to the improvement in acoustic performance is also an inefficient logarithmic increase.

[0003] Fiber materials possess porous characteristics, which can generate sound wave loss within a corresponding frequency range. However, it is difficult to achieve excellent sound absorption when the fiber material is too thin. Therefore, methods such as increasing the thickness of the fiber material and combining it with various layered structures exist to improve the overall acoustic properties of the fabric. However, the bonding effect between the layers or the reasonable limitations on the acoustic performance of the layers themselves are lacking. Layer bonding methods include sewing or hot melt adhesive. When using hot melt adhesive, the adhesive can clog the pores of the fiber fabric itself, and the high-temperature environment used in the curing process of hot melt adhesive also poses a risk of melting and pore disappearance for each fiber fabric layer. When using sewing, the fiber fabric layers cannot form a good bond, and the interfacial acoustic dissipation is significantly weakened, thus weakening the acoustic properties. For example, Chinese patent CN112659689A proposes a sound-absorbing material formed by bonding multiple fabric layers together; the upper layer is a composite material of bark crepe fabric, honeycomb fabric, and flame-melted laminated fabric, with various layers bonded together using hot melt and sewing methods respectively. The complex process also hinders the expression of the acoustic characteristics of each layer structure and the dissipation effect at the layer structure interface. Summary of the Invention

[0004] The main objective of this invention is to provide a composite sound-absorbing cloth, its manufacturing process, and its application, aiming to solve the problem of the lack of reasonable limitations on the bonding method between the layers and the acoustic performance of the layers themselves in multilayered sound-absorbing cloths.

[0005] To achieve the above objectives, the present invention provides a composite sound-absorbing cloth, comprising:

[0006] The first fiber cloth layer has a surface density of 20 to 60 grams per square meter, a thickness of 0.1 to 0.5 millimeters, and has 1 to 3 layers that are stacked together.

[0007] The second fiber cloth layer has an areal density that is 4.0ρ2 to 6.0ρ2 times that of the first fiber cloth layer, a thickness of 1.5 to 2.5 mm, and 1 to 4 layers. Here, ρ2 is the ratio of the raw material density of the second fiber cloth layer to the raw material density of the first fiber cloth layer.

[0008] The third fiber fabric layer has an areal density that is 9.0ρ3 to 11.0ρ3 times that of the first fiber fabric layer, a thickness of 1.5 to 2.5 mm, and a number of layers of the third fiber fabric layer of 1 to 4, wherein ρ3 is the ratio of the raw material density of the third fiber fabric layer to the raw material density of the first fiber fabric layer.

[0009] The fourth fiber fabric layer has an areal density that is 2.0ρ4 to 4.0ρ4 times that of the first fiber fabric layer, a thickness of 0.5 to 2.0 mm, and has 1 to 3 layers that are stacked together. ρ4 is the ratio of the raw material density of the fourth fiber fabric layer to the raw material density of the first fiber fabric layer.

[0010] The materials of the first fiber cloth layer, the second fiber cloth layer, the third fiber cloth layer, and the fourth fiber cloth layer are selected from synthetic fiber cloth, natural fiber cloth, and recycled fiber cloth; the first fiber cloth layer, the second fiber cloth layer, the third fiber cloth layer, and the fourth fiber cloth layer are stacked and bonded by an adhesive dot layer, the adhesive dot layer includes dispersed micro adhesive dots, the diameter of the micro adhesive dots is between 5 and 500 micrometers, and the second fiber cloth layer and the third fiber cloth layer are disposed between the first fiber cloth layer and the fourth fiber cloth layer.

[0011] Furthermore, the density of the first fiber fabric layer is 30 to 50 grams per square meter;

[0012] The second fiber fabric has a surface density of 160 to 240 grams per square meter;

[0013] The density of the third fiber fabric layer is 320 to 480 grams per square meter;

[0014] The density of the fourth fiber fabric layer is 90 to 150 grams per square meter;

[0015] The values ​​of ρ2, ρ3 and ρ4 are all between 0.8 and 1.2.

[0016] Furthermore, the second fiber fabric layer and the third fiber fabric layer are made of the same material.

[0017] Furthermore, both the second and third fiber fabric layers have 2 to 4 layers.

[0018] Furthermore, the second fiber fabric layer and the third fiber fabric layer are interleaved and stacked.

[0019] Furthermore, the first fiber fabric layer, the second fiber fabric layer, the third fiber fabric layer, and the fourth fiber fabric layer are textile fabrics.

[0020] Furthermore, the first fiber fabric layer, the second fiber fabric layer, the third fiber fabric layer, and the fourth fiber fabric layer are joined together by a face stitching structure.

[0021] Furthermore, the second fiber fabric layer and the third fiber fabric layer are perforated in the thickness direction by a group of micropores consisting of needle-shaped micropores with a diameter of 0.02 to 0.2 mm, wherein the planar distance between two adjacent micropores is less than 2 mm.

[0022] The present invention also provides a manufacturing process for preparing the above-mentioned composite sound-absorbing cloth, comprising:

[0023] S1. When stacking the first fiber cloth layer, the second fiber cloth layer, the third fiber cloth layer and the fourth fiber cloth layer in a preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain a composite sound-absorbing cloth composite.

[0024] S2. A pressing process is performed on the composite sound-absorbing fabric stack to obtain a compressed body in the thickness direction;

[0025] S3. The pressing process is carried out on the pressed body.

[0026] Furthermore, step S3 is followed by:

[0027] S4. A surface stitching structure that runs through the thickness direction is arranged in the plane of the composite sound-absorbing cloth.

[0028] The present invention also provides a manufacturing process for preparing the above-mentioned composite sound-absorbing cloth, comprising:

[0029] P1. When stacking the second and third fiber cloth layers in a preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain an intermediate composite.

[0030] P2. After applying thickness-direction pressure and curing to the intermediate composite, an intermediate pressed body is obtained.

[0031] P3. Using a preset mold, micro-hole groups are processed on the intermediate pressing body to obtain an intermediate finished body, wherein the preset mold is a workpiece with puncture needles with a diameter ranging from 0.02 to 0.2 mm on its surface, and the distance between adjacent puncture needles is less than 2 mm.

[0032] P4. When stacking the first fiber cloth layer, the intermediate finished body and the fourth fiber cloth layer in the preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain the composite sound-absorbing cloth composite body.

[0033] P5. The composite sound-absorbing cloth lamination is subjected to a thickness-direction pressure application process and a curing process.

[0034] The present invention provides an application of the above-mentioned composite sound-absorbing cloth in an enclosed space, wherein multiple tables and / or multiple chairs are provided in the enclosed space, including: placing the composite sound-absorbing cloth on the suspended bottom surface of the tables and / or chairs in the enclosed space.

[0035] The composite sound-absorbing cloth, manufacturing process, and application provided by this invention, by introducing the factor of fiber cloth layer raw material density and limiting the thickness of each fiber cloth layer, allows the difference in fiber cloth layer density to reflect the difference in acoustic properties. Fiber cloth layers with different surface densities can produce superior sound absorption effects at different frequencies, and the interfaces between the fiber cloth layers with different surface densities form a dissipation effect. The adhesive layer bonds the adjacent fiber cloth layers together, and the micro-adhesive dots in the adhesive layer are small in size, only blocking a very small number of pores in the fiber cloth layers. Thus, while ensuring excellent bonding, the pores of the fiber cloth layers themselves are also preserved, resulting in a significant improvement in the acoustic effect of the composite sound-absorbing cloth. The material properties of the composite sound-absorbing cloth make it easy to install on existing structures, thereby improving the acoustic effect in the environment. Attached Figure Description

[0036] Figure 1 This is a cross-sectional schematic diagram of a composite sound-absorbing cloth according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the adhesive dot layer on the second fiber cloth layer in a composite sound-absorbing cloth according to an embodiment of the present invention;

[0038] Figure 3 yes Figure 2 A magnified view of a portion of position A in the middle;

[0039] Figure 4 This is a schematic diagram of the microporous layer of the second fiber cloth layer in the composite sound-absorbing cloth of the second embodiment of the present invention;

[0040] Figure 5 yes Figure 4 A magnified view of the area at position B in the middle;

[0041] Figure 6 This is a cross-sectional schematic diagram of the composite sound-absorbing cloth according to the third embodiment of the present invention;

[0042] Figure 7 This is a schematic diagram illustrating the application of the composite sound-absorbing cloth of the present invention.

[0043] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0044] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0045] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” “the,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, units, modules, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, units, modules, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connection or wireless coupling. The term “and / or” as used herein includes all or any of the units and all combinations of one or more associated listed items.

[0046] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0047] Reference Figures 1 to 6 In one embodiment of the present invention, a composite sound-absorbing cloth includes:

[0048] The first fiber fabric layer 100 has a surface density of 20 to 60 grams per square meter, a thickness of 0.1 to 0.5 millimeters, and has 1 to 3 layers that are stacked together.

[0049] The second fiber fabric layer 200 has an areal density that is 4.0ρ2 to 6.0ρ2 times that of the first fiber fabric layer 100, a thickness of 1.5 to 2.5 mm, and 1 to 4 layers. Wherein, ρ2 is the ratio of the raw material density of the second fiber fabric layer 200 to the raw material density of the first fiber fabric layer 100.

[0050] The third fiber fabric layer 300 has an areal density that is 9.0ρ3 to 11.0ρ3 times that of the first fiber fabric layer 100. The thickness of the third fiber fabric layer 300 is 1.5 to 2.5 mm, and the number of layers of the third fiber fabric layer 300 is 1 to 4. Wherein, ρ3 is the ratio of the raw material density of the third fiber fabric layer 300 to the raw material density of the first fiber fabric layer 100.

[0051] The fourth fiber fabric layer 400 has an areal density that is 2.0ρ4 to 4.0ρ4 times that of the first fiber fabric layer 100. The thickness of the fourth fiber fabric layer 400 is 0.5 to 2.0 mm. The fourth fiber fabric layer 400 has 1 to 3 layers that are stacked together. ρ4 is the ratio of the raw material density of the fourth fiber fabric layer 400 to the raw material density of the first fiber fabric layer 100.

[0052] The materials of the first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300, and the fourth fiber cloth layer 400 are selected from synthetic fiber cloth, natural fiber cloth, and recycled fiber cloth. The first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300, and the fourth fiber cloth layer 400 are stacked and bonded by an adhesive dot layer 500. The adhesive dot layer 500 includes dispersed micro-adhesive dots with a diameter of 5 to 500 micrometers. The second fiber cloth layer 200 and the third fiber cloth layer 300 are disposed between the first fiber cloth layer 100 and the fourth fiber cloth layer 400.

[0053] In existing technologies, fiber materials have porous characteristics and can generate sound wave loss within a corresponding frequency range. However, it is difficult to achieve a high-quality sound absorption effect when the fiber material is too thin. Therefore, there are ways to improve the acoustic properties of the entire fabric material by increasing the thickness of the fiber material and by compositing various layer structures. However, the bonding effect between the layers or the reasonable limitation of the acoustic performance of the layers themselves is lacking. In addition to the complexity of the process, it is also not conducive to the expression of the acoustic characteristics of each layer and the dissipation effect of the layer interface.

[0054] In this invention, the first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300, and the fourth fiber cloth layer 400 are fiber cloth layers selected from one of three material types: synthetic fiber cloth, natural fiber cloth, and recycled fiber cloth. Firstly, the areal density selection of the fiber cloth layers is not limited to fewer than four, but rather limited to at least four. This limitation is due to considerations of sound absorption and strength performance requirements. Then, by introducing the factor of fiber cloth layer raw material density and limiting the thickness of each fiber cloth layer, the difference in areal density of the first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300, and the fourth fiber cloth layer 400 can reflect differences in acoustic properties. Fiber cloth layers with different areal densities can each produce superior sound absorption effects at different frequencies, and the structurally different interfaces formed between the aforementioned fiber cloth layers with different areal densities create dissipation effects. This invention provides preferred areal density guidelines for the second fiber cloth layer 200, the third fiber cloth layer 300, and the fourth fiber cloth layer 400. Generally, except for special types of materials, the density of fibers is around 1.3 grams per cubic centimeter. The difference in areal density between the first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300, and the fourth fiber cloth layer 400 is set to be relatively large. At this time, even if different types of fiber cloth layers are used, their porosity can still be different; and different types of fiber cloth layers can also bring about an improvement in the interfacial dissipation effect due to the difference in materials.

[0055] Specifically, the first fiber fabric layer 100, the second fiber fabric layer 200, the third fiber fabric layer 300, and the fourth fiber fabric layer 400 are four different fiber fabric layers. The first fiber fabric layer 100, the second fiber fabric layer 200, the third fiber fabric layer 300, and the fourth fiber fabric layer 400 can be made of a single layer of warp and weft yarns woven together, or can be non-woven fabric, etc. For example, if the first fiber fabric layer 100, the second fiber fabric layer 200, the third fiber fabric layer 300, and the fourth fiber fabric layer 400 are made of the same material, and the areal density of the first fiber fabric layer 100 is limited to 50 grams per square meter, then the areal density of the second fiber fabric layer 200 ranges from 200 to 300 grams per square meter (e.g., 250), the areal density of the third fiber fabric layer 300 ranges from 450 to 550 grams per square meter (e.g., 500), and the areal density of the fourth fiber fabric layer 400 ranges from 100 to 200 grams per square meter (e.g., 150).

[0056] The first fiber cloth layer 100 is the bottom layer, mainly used to form structural strength and some acoustic properties. Although its surface density is 20 to 60 grams per square meter, its thickness is only 0.1 to 0.5 millimeters, so its bulk density is relatively large. At this time, the first fiber cloth layer 100 can provide superior structural strength. At the same time, since it is a cloth layer rather than a membrane layer, it can also achieve acoustic properties.

[0057] The second fiber cloth layer 200 and the third fiber cloth layer 300 are disposed between the first fiber cloth layer 100 and the fourth fiber cloth layer 400 and are relatively thick. Together, they achieve the main acoustic effect of the composite sound-absorbing cloth 001. Taking a three-layer second fiber cloth layer 200 as an example, the three layers of second fiber cloth layer 200 are not limited to being three layers stacked together; the third fiber cloth layer 300 can also be inserted in between. The interface formed between the second fiber cloth layer 200 and the third fiber cloth layer 300, or the interface formed between the two and the first fiber cloth layer 100 and the fourth fiber cloth layer 400, can provide a positive effect on noise dissipation.

[0058] The fourth fiber cloth layer 400 is the surface material, relatively thin, with a surface density ranging from 100 to 200 grams per square meter. It provides acoustic permeability while also providing some sound absorption. Of course, the fourth fiber cloth layer 400 also restricts the movement of the second fiber cloth layer 200 and the third fiber cloth layer 300. The thickness of the fourth fiber cloth layer 400 should not be too large, otherwise its installation characteristics and acoustic permeability will be adversely affected. As the outermost surface structure, the thickness and surface density of the fourth fiber cloth layer 400 need to be within a suitable range to achieve a balance between sound permeability and sound absorption performance.

[0059] In the process of using composite sound-absorbing cloth 001, the fourth fiber cloth layer 400 is set on the outermost layer. The fourth fiber cloth layer 400 can be dyed or have a surface pattern treated to improve the appearance of the composite sound-absorbing cloth 001. Alternatively, a decorative surface material with sound transmission properties can be set on the side of the fourth fiber cloth layer 400 that is opposite to the third fiber cloth layer 300.

[0060] When acoustic performance is not considered, there are various ways to connect the fiber cloth layers, such as sewing or hot melt adhesive. While hot melt adhesive provides excellent bonding between the fiber cloth layers, it can clog the pores within the layers, and the high temperature during curing poses a risk of melting and pore disappearance. Sewing, on the other hand, prevents proper adhesion between the fiber cloth layers, significantly weakening interfacial acoustic dissipation and thus reducing acoustic properties. In this invention, the adhesive dot layer 500 bonds adjacent fiber cloth layers. The micro-adhesive dots in the adhesive dot layer 500 are small, only clogging a very small number of pores in the fiber cloth layers. Therefore, while maintaining excellent bonding (ensuring good interfacial acoustic dissipation between the fiber cloth layers), the pores within the fiber cloth layers are also preserved, resulting in a significant improvement in the acoustic performance of the composite sound-absorbing cloth. The adhesive used can be various environmentally friendly adhesives (formaldehyde-free, etc.). When this fiber cloth layer is laid on top of the previous fiber cloth layer, it is dispersed between the fiber cloth layers by spraying, thus forming an adhesive dot layer 500. Due to the characteristics of the spraying process, the spacing between the micro-adhesive dots is in the range of 50 to 200 micrometers. It should be noted that the micro-adhesive dots may be absorbed by the various fiber cloth layers and no longer have the original spherical shape; in this case, they are still defined as micro-adhesive dots. In a preferred embodiment, the diameter of the micro-adhesive dots is 50 to 100 micrometers.

[0061] The thickness of the composite sound-absorbing cloth 001 ranges from 5 mm to 20 mm. If the thickness of the composite sound-absorbing cloth 001 is too low, it indicates a low total number of layers (first fiber cloth layer 100, second fiber cloth layer 200, third fiber cloth layer 300, and fourth fiber cloth layer 400), or in other words, a low overall areal density. This is detrimental to the sound absorption effect. Conversely, increasing or decreasing the thickness of the composite sound-absorbing cloth 001 does not result in a linear increase in sound absorption but rather a logarithmic increase, which is unfavorable for ease of operation and cost during application. Therefore, in this embodiment, the total thickness of the composite sound-absorbing cloth 001 is limited, achieving a trade-off between cost and acoustic characteristics within this range.

[0062] In summary, by incorporating the density of the fiber cloth material and limiting the thickness of each fiber cloth layer, the difference in the surface density of the fiber cloth can reflect the difference in acoustic properties. Fiber cloth layers with different surface densities can each produce superior sound absorption effects at different frequencies, and the different interfaces formed between these fiber cloth layers create a dissipation effect. The adhesive layer 500 bonds adjacent fiber cloth layers together, and the micro-adhesive dots in the adhesive layer 500 are small in size, only blocking a very small number of pores in the fiber cloth layers. Thus, while ensuring excellent bonding, the pores of the fiber cloth layers themselves are preserved, resulting in a significant improvement in the acoustic performance of the composite sound-absorbing cloth 001. Furthermore, the material properties of the composite sound-absorbing cloth 001 allow it to be easily installed on existing structures, thereby improving the acoustic performance in the environment.

[0063] In one embodiment, the areal density of the first fiber fabric layer 100 is 30 to 50 grams per square meter;

[0064] The second fiber fabric layer has a surface density of 160 to 240 grams per square meter;

[0065] The third fiber fabric layer has a surface density of 320 to 480 grams per square meter;

[0066] The fourth fiber fabric layer has a surface density of 90 to 150 grams per square meter;

[0067] The values ​​of ρ2, ρ3 and ρ4 are all between 0.8 and 1.2.

[0068] In this embodiment, preferred areal density and thickness are given for the first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300 and the fourth fiber cloth layer 400, and the density difference between the four limiting cloth layers is small. Within the above-mentioned limits, the sound absorption effect of the composite sound-absorbing cloth 001 is superior.

[0069] In one embodiment, the second fiber fabric layer 200 and the third fiber fabric layer 300 are made of the same material.

[0070] In this embodiment, the second fiber cloth layer 200 and the third fiber cloth layer 300 are made of the same material. Therefore, different surface densities easily lead to differences in their acoustic characteristics, resulting in good sound absorption across the entire frequency range. Simultaneously, the difference at their interface also contributes to excellent dissipation. The selective setting of the number of layers in the second fiber cloth layer 200 and the third fiber cloth layer 300 also allows for optimized noise absorption across various frequency bands.

[0071] In one embodiment, the second fiber fabric layer 200 and the third fiber fabric layer 300 each have 2 to 4 layers.

[0072] In this embodiment, increasing the number of layers of the second fiber cloth layer 200 and the third fiber cloth layer 300 can improve the sound absorption or the overall sound absorption coefficient to a certain extent. During the setup process, all the second fiber cloth layers 200 can be stacked to form a whole, and all the third fiber cloth layers 300 can be stacked to form a whole; or the second fiber cloth layers 200 and the third fiber cloth layers 300 can be staggered.

[0073] Reference Figure 1 In one embodiment, the second fiber fabric layer 200 and the third fiber fabric layer 300 are staggered and overlapped.

[0074] In this embodiment, the staggered arrangement increases the number of interfaces that create differences in acoustic performance, contributing to the overall improvement in acoustic characteristics. For example, if both the second fiber cloth layer 200 and the third fiber cloth layer 300 have two layers and the stacking order is second fiber cloth layer 200, third fiber cloth layer 300, second fiber cloth layer 200 and third fiber cloth layer 300, then there are three different interfaces, which increases the contribution to interface dissipation.

[0075] In one embodiment, the first fiber fabric layer 100, the second fiber fabric layer 200, the third fiber fabric layer 300, and the fourth fiber fabric layer 400 are textile fabrics.

[0076] While nonwoven fabrics can also have their areal density adjusted, in the prior art, adjusting the areal density of woven fabrics is simpler, and various types of fibers can be woven. Specifically, the areal density of woven fabrics can be adjusted by changing the weaving interval between the warp and weft threads, making it convenient to obtain fiber layers of different areal densities during production or procurement. In other embodiments, the first fiber layer 100, the second fiber layer 200, the third fiber layer 300, and the fourth fiber layer 400 can be nonwoven fabrics.

[0077] In one embodiment, the first fiber fabric layer 100, the second fiber fabric layer 200, the third fiber fabric layer 300, and the fourth fiber fabric layer 400 are integrally joined by a face-stitched structure.

[0078] In this embodiment, the bonding effect of the adhesive layer 500 is enhanced by the surface-sewn structure, thus fixing the composite sound-absorbing cloth 001 and reducing the risk of detachment between the individual fiber layers. During processing, when stacking the fiber layers, the adhesive is sprayed in a mist form between the fiber layers. Then, a preset pressure is applied in the thickness direction of the composite sound-absorbing cloth 001. After the adhesive layer 500 is partially or completely cured, the composite sound-absorbing cloth 001 is further fixed by sewing, improving its physical properties and thus ensuring its acoustic performance. In particular, during application, the composite sound-absorbing cloth 001 can be sewn with an edge-sealing structure. During the sewing process of the edge-sealing structure, the surface-sewn structure can be processed simultaneously.

[0079] Reference Figures 3 to 4 In one embodiment, the second fiber cloth layer 200 and the third fiber cloth layer 300 are perforated in the thickness direction by a micropore group 600 consisting of needle-shaped micropores with a diameter of 0.02 to 0.2 mm, wherein the planar distance between two adjacent micropores is less than 2 mm.

[0080] In this embodiment, the sound absorption effect is improved by setting micropore groups 600 on the second fiber cloth layer 200 and the third fiber cloth layer 300. Specifically, the diameter of the micropores is between 0.02 and 0.2 mm. Combining the characteristics of needle-punched structure and textile structure, the sound absorption performance is improved. For example, if the second fiber cloth layer 200 is woven from synthetic fibers, then the pores on the second fiber cloth layer 200 can only be the gaps between synthetic fibers. However, in this embodiment, the micropore group 600 is added, thus increasing the pore size of the second fiber cloth layer 200. It should be noted that the micropore group 600 can be formed simultaneously on the second fiber cloth layer 200 and the third fiber cloth layer 300 as a whole. That is, the second fiber cloth layer 200 and the third fiber cloth layer 300 are combined and then punctured using a tool, or the second fiber cloth layer 200 and the third fiber cloth layer 300 are punctured separately. The first fiber cloth layer 100 and the fourth fiber cloth layer 400 do not have micropore groups 600 to ensure structural strength. However, the second fiber cloth layer 200 and the third fiber cloth layer 300 have micropore groups 600, which reduces both structural strength and surface smoothness to some extent. Therefore, by enclosing the second fiber cloth layer 200 and the third fiber cloth layer 300 inside the first fiber cloth layer 100 and the fourth fiber cloth layer 400, the acoustic properties are guaranteed while also ensuring the overall structural strength. In this embodiment, the first fiber fabric layer 100 has a surface density of 40 grams per square meter and a thickness of 0.2 millimeters; the second fiber fabric layer 200 has a surface density of 200 grams per square meter and a thickness of 2.0 millimeters; the third fiber fabric layer 300 has a surface density of 400 grams per square meter and a thickness of 2.0 millimeters; and the fourth fiber fabric layer 400 has a surface density of 120 grams per square meter and a thickness of 0.5 millimeters. The first fiber fabric layer 100, the second fiber fabric layer 200, the third fiber fabric layer 300, and the fourth fiber fabric layer 400 are all synthetic fiber materials. The diameter of the micropores is 0.1 millimeters, and the planar distance between the micropores is less than 1 millimeter. Tested with a Bruel & Kjaer-2250 instrument, the sound absorption coefficients are as follows: 0.45, 0.56, 0.66, 0.75, 0.88 and 0.85 at 125Hz, 250Hz, 500Hz, 1000Hz, 2000Hz and 4000Hz respectively, demonstrating excellent sound absorption performance across the entire frequency range.

[0081] The present invention also provides a manufacturing process for the above-mentioned composite sound-absorbing cloth, comprising:

[0082] S1. When stacking the first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300 and the fourth fiber cloth layer 400 in a preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain a composite sound-absorbing cloth composite.

[0083] S2. A pressing process is performed on the composite sound-absorbing fabric stack to obtain a compressed body in the thickness direction;

[0084] S3. The pressing process is carried out on the pressed body.

[0085] In this embodiment, step S1 is a lamination process. The first fiber cloth layer 100, the second fiber cloth layer 200, the third fiber cloth layer 300, and the fourth fiber cloth layer 400 are all fiber cloth layers. Taking the lamination process of two fiber cloth layers as an example, adhesive can be sprayed onto the upper surface of the first fiber cloth layer or onto the lower surface of the second fiber cloth layer. Thus, during the lamination process of two fiber cloth layers, the adhesive sprayed at the interface forms an adhesive dot layer 500 composed of micro-adhesive dots. The adhesive dot layer 500 bonds adjacent fiber cloth layers. Simultaneously, the micro-adhesive dots in the adhesive dot layer 500 are small in size and only block a very small number of pores in the fiber cloth layers. Therefore, under the premise of excellent bonding effect (maintaining the interfacial acoustic dissipation effect between each fiber cloth layer), while also preserving the pores of the fiber cloth layers themselves, the acoustic effect of the composite sound-absorbing cloth 001 is significantly improved. It should be noted that the micro-adhesive dots may be absorbed by each fiber cloth layer and no longer possess their original spherical shape; in this case, they are still defined as micro-adhesive dots. By adjusting the spraying process, the diameter of the micro-adhesive dots can be specifically adjusted.

[0086] Step S2 is the pressing process, which applies pressure along the thickness direction to the composite sound-absorbing fabric stack to obtain a qualified bonding strength between adjacent fiber fabric layers. Since the overall thickness of the composite sound-absorbing fabric stack is relatively small, a pressing operation is not required after each layer of fiber fabric is stacked. In this embodiment, the pressing process is performed after all the stacking processes are completed, thereby improving operational efficiency.

[0087] Step S3 is the curing process, which can be carried out by heating or naturally at room temperature, and pressure curing can also be selected. During the curing process, the goal is to achieve excellent bonding between the fiber cloth layers. The bonding effect between the fiber cloth layers can be determined by microscopic images of the cross-section or by the acoustic performance of the final product. The cured body can directly form composite sound-absorbing cloth 001, or it can be formed after some auxiliary processes (sewing or edge bonding, etc.) are performed after the curing process.

[0088] Furthermore, step S3 is followed by:

[0089] S4. A surface stitching structure that runs through the thickness direction is arranged in the plane of the composite sound-absorbing cloth 001.

[0090] In this embodiment, after the pressing body undergoes the curing process, it is further fixed by stitching, and the surface stitching structure has minimal negative impact on the overall acoustic performance. The layout trajectory of the surface stitching structure can be a continuous line, a discontinuous line, or scattered points, etc. When the composite sound-absorbing cloth 001 has stitched edges, the above surface stitching structure can be processed simultaneously.

[0091] The present invention also provides a manufacturing process for the above-mentioned composite sound-absorbing cloth, comprising:

[0092] P1. When stacking the second fiber cloth layer 200 and the third fiber cloth layer 300 in a preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain an intermediate composite.

[0093] P2. After applying thickness-direction pressure and curing to the intermediate composite, an intermediate pressed body is obtained.

[0094] P3. Using a preset mold, micro-hole group 600 is processed on the intermediate pressing body to obtain an intermediate finished body. The preset mold is a workpiece with puncture needles with a diameter in the range of 0.02 to 0.2 mm on its surface and the distance between adjacent puncture needles is less than 2 mm.

[0095] P4. When stacking the first fiber cloth layer 100, the intermediate finished body and the fourth fiber cloth layer 400 in the preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain the composite sound-absorbing cloth composite body.

[0096] P5. The composite sound-absorbing cloth lamination is subjected to a thickness-direction pressure application process and a curing process.

[0097] In this embodiment, steps P1, P2, P4, and P5 are the same as in the aforementioned embodiment. In step P3, the second fiber cloth layer 200 and the third fiber cloth layer 300 are first bonded together and fully cured in the previous steps, and then the microporous assembly 600 is processed. The pre-formed mold can be roller-shaped or flat, etc., and has a group of puncture needles on it. Depending on the shape of the pre-formed mold, a processing method such as rolling or pressing is used to process the intermediate pressing body using the pre-formed mold, thereby forming the microporous assembly 600. It should be noted that the processing action of the pre-formed mold may need to be repetitive. For example, if the pre-formed mold is roller-shaped, the intermediate pressing body may need to be repeatedly rolled multiple times to form the microporous assembly 600 that meets the dimensional requirements.

[0098] The present invention also provides an application of composite sound-absorbing cloth in an enclosed space, wherein multiple tables and / or multiple chairs are provided in the enclosed space, including: placing the composite sound-absorbing cloth 001 on the suspended bottom surface of the tables and / or chairs in the enclosed space.

[0099] In this embodiment, the enclosed space includes classrooms, cinemas, theaters, live broadcast rooms, offices, tea rooms, dining rooms, listening rooms, living rooms, home theaters, or conference rooms, etc. These enclosed spaces typically have multiple chairs or matching tables. When the tables and / or chairs have suspended bottom surfaces, composite sound-absorbing cloth 001 is placed on them. For example, composite sound-absorbing cloth 001 can be fixed to the bottom surface of chair seats and desks in a classroom. The sound absorption properties of the composite sound-absorbing cloth 001 can improve the acoustic environment of the classroom, such as absorbing noise (especially low-frequency noise) and improving reverberation parameters. Even by selectively placing composite sound-absorbing cloth 001 on the suspended bottom surfaces of some tables and / or chairs, minor adjustments to acoustic performance can be achieved. The fixing method of the composite sound-absorbing cloth 001 can be varied, including chemical methods (adhesives, etc.) or physical methods (nail fastening, etc.). Physical methods are preferred because they are safe and environmentally friendly while minimizing interference with the acoustic characteristics of the composite sound-absorbing cloth 001.

[0100] Referring to Table 1, Sample 1 consisted of student desks and chairs, with the bottom of the desks and chairs covered with composite sound-absorbing cloth 001. The desks were 660 mm long, 470 mm deep, and 730 mm high, while the chairs were 500 mm long, 500 mm deep, and 730 mm high. The desks were made entirely of aluminum alloy, and the chairs were made entirely of plastic. The desks and chairs were evenly distributed in the laboratory, arranged in 5 rows, with 4 sets of desks and chairs in each row, for a total of 20 sets. The total area of ​​the sound-absorbing cloth was 10.6 square meters. The desks and chairs were closely joined side to side, with a spacing of 300 mm between desks in each row. The net volume of the reverberation chamber was 230 cubic meters. The test points were randomly distributed, and each test point was tested 3 times and averaged. Sample 2 was consistent with Sample 1, except that it did not have composite sound-absorbing cloth 001. It should be noted that the data in Table 1 were obtained by dividing the sound absorption of the 20 sets of desks and chairs by 20, i.e., a comparison of a single set of desks and chairs.

[0101] Table 1. Comparison of sound absorption tests of a single set of tables and chairs between Sample 1 and Sample 2.

[0102]

[0103] As can be seen from the above data, the introduction of composite sound-absorbing cloth 001 achieves superior acoustic performance.

[0104] In summary, the composite sound-absorbing cloth, manufacturing process, and application provided by this invention, through the introduction of the density of the fiber cloth layer raw materials and the limitation of the thickness of each fiber cloth layer, allow the difference in the surface density of the fiber cloth layer to reflect the difference in acoustic properties. Fiber cloth layers with different surface densities can each produce superior sound absorption effects at different frequencies, and the different interfaces formed between these fiber cloth layers create a dissipation effect. The adhesive layer 500 bonds adjacent fiber cloth layers together, and the micro-adhesive dots in the adhesive layer 500 are small in size, only blocking a very small number of pores in the fiber cloth layer. Therefore, while achieving excellent bonding, the pores of the fiber cloth layer itself are preserved, resulting in a significant improvement in the acoustic effect of the composite sound-absorbing cloth 001. The material characteristics of the composite sound-absorbing cloth 001 allow it to be easily installed on existing structures, thereby improving the acoustic effect in the environment.

[0105] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A composite sound-absorbing cloth, characterized in that, include: The first fiber fabric layer (100) has a surface density of 20 to 60 grams per square meter, a thickness of 0.1 to 0.5 millimeters, and has 1 to 3 layers that are stacked together. The second fiber cloth layer (200) has an areal density that is 4.0ρ2 to 6.0ρ2 times that of the first fiber cloth layer (100), the thickness of the second fiber cloth layer (200) is 1.5 to 2.5 mm, and the number of layers of the second fiber cloth layer (200) is 1 to 4, wherein ρ2 is the ratio of the raw material density of the second fiber cloth layer (200) to the raw material density of the first fiber cloth layer (100); The third fiber fabric layer (300) has an areal density that is 9.0ρ3 to 11.0ρ3 times that of the first fiber fabric layer (100), the thickness of the third fiber fabric layer (300) is 1.5 to 2.5 mm, and the number of layers of the third fiber fabric layer (300) is 1 to 4, wherein ρ3 is the ratio of the raw material density of the third fiber fabric layer (300) to the raw material density of the first fiber fabric layer (100); The fourth fiber fabric layer (400) has an areal density that is 2.0ρ4 to 4.0ρ4 times that of the first fiber fabric layer (100), the thickness of the fourth fiber fabric layer (400) is 0.5 to 2.0 mm, and the fourth fiber fabric layer (400) has 1 to 3 layers that are stacked together, wherein ρ4 is the ratio of the raw material density of the fourth fiber fabric layer (400) to the raw material density of the first fiber fabric layer (100); The materials of the first fiber cloth layer (100), the second fiber cloth layer (200), the third fiber cloth layer (300), and the fourth fiber cloth layer (400) are selected from synthetic fiber cloth, natural fiber cloth, and recycled fiber cloth; the first fiber cloth layer (100), the second fiber cloth layer (200), the third fiber cloth layer (300), and the fourth fiber cloth layer (400) are stacked and bonded by an adhesive dot layer (500), the adhesive dot layer (500) includes dispersed micro adhesive dots, the diameter of the micro adhesive dots is between 5 and 500 micrometers, and the second fiber cloth layer (200) and the third fiber cloth layer (300) are disposed between the first fiber cloth layer (100) and the fourth fiber cloth layer (400); The second fiber fabric layer (200) and the third fiber fabric layer (300) are perforated in the thickness direction by a group of micropores (600) consisting of needle-shaped micropores with a diameter of 0.02 to 0.2 mm, wherein the planar distance between two adjacent micropores is less than 2 mm; The first fiber fabric layer (100), the second fiber fabric layer (200), the third fiber fabric layer (300) and the fourth fiber fabric layer (400) are textile fabrics; wherein, the values ​​of ρ2, ρ3 and ρ4 are all between 0.8 and 1.

2.

2. The composite sound-absorbing cloth according to claim 1, characterized in that, The areal density of the first fiber fabric layer (100) is 30 to 50 grams per square meter; The areal density of the second fiber fabric layer (200) is 160 to 240 grams per square meter; The areal density of the third fiber fabric layer (300) is 320 to 480 grams per square meter; The areal density of the fourth fiber fabric layer (400) is 90 to 150 grams per square meter.

3. The composite sound-absorbing cloth according to claim 1, characterized in that, The second fiber fabric layer (200) and the third fiber fabric layer (300) are made of the same material.

4. The composite sound-absorbing cloth according to claim 1, characterized in that, The second fiber fabric layer (200) and the third fiber fabric layer (300) each have 2 to 4 layers.

5. The composite sound-absorbing cloth according to claim 4, characterized in that, The second fiber fabric layer (200) and the third fiber fabric layer (300) are staggered and overlapped.

6. The composite sound-absorbing cloth according to any one of claims 1 to 5, characterized in that, The first fiber fabric layer (100), the second fiber fabric layer (200), the third fiber fabric layer (300) and the fourth fiber fabric layer (400) are integrally joined by a face stitching structure.

7. A process for manufacturing composite sound-absorbing cloth, used to prepare the composite sound-absorbing cloth according to claim 1, characterized in that, include: P1. When stacking the second fiber cloth layer (200) and the third fiber cloth layer (300) in a preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain an intermediate composite. P2. After applying thickness-direction pressure and curing to the intermediate composite, an intermediate pressed body is obtained. P3. Using a preset mold, micro-hole groups (600) are processed on the intermediate pressing body to obtain an intermediate finished body, wherein the preset mold is a workpiece with puncture needles with a diameter in the range of 0.02 to 0.2 mm on its surface, and the distance between adjacent puncture needles is less than 2 mm. P4. When stacking the first fiber cloth layer (100), the intermediate finished body and the fourth fiber cloth layer (400) in the preset order, the adhesive is sprayed onto the stacking interface in the form of a mist to obtain the composite sound-absorbing cloth composite body. P5. The composite sound-absorbing cloth lamination is subjected to a thickness-direction pressure application process and a curing process.

8. The application of the composite sound-absorbing cloth according to any one of claims 1 to 6 in an enclosed space, wherein the enclosed space is provided with a plurality of tables and / or a plurality of chairs, characterized in that, include: The composite sound-absorbing cloth is placed on the suspended bottom surface of a table and / or chair in an enclosed space.

Images