Sound-absorbing fabric based on triboelectrification by vibration, preparation method thereof and application

Abstract

The present invention discloses a sound-absorbing fabric that causes contact electrification of materials based on vibration, as well as a preparation method and application thereof, belonging to the field of sound-absorbing materials. The sound-absorbing fabric provided by the present invention comprises an upper fleece fabric and a lower fleece fabric. The upper fleece fabric and the lower fleece fabric contain vibration unit layers with different electrostatic sequences. The different vibration unit layers are electrified by contact separation, resulting in charge transfer, and converting sound energy into electrical energy; at the same time, the porous structure of the fabric itself is utilized to convert sound energy into heat energy, thereby achieving a sound absorption effect. Based on the principle of porous sound absorption, the present invention provides the fabric with an additional way to consume sound energy through contact electrification, thereby making the fabric more efficient in sound absorption and being able to selectively reduce noise of specific frequencies, especially low-frequency noise. The resulting fabric is light, thin, and breathable. The sound-absorbing fabric produced by the present invention can be used to prepare home textile fabrics with sound absorption and noise reduction effects.

Description

Technical Field

[0001] The invention belongs to the field of sound-absorbing materials and relates to a sound-absorbing fabric, in particular to a sound-absorbing fabric that is electrified by contact of materials through vibration, and a preparation method and application thereof. Background Art

[0002] With economic development, urbanization is an inevitable trend. This over-concentration of populations creates numerous problems, with noise being a significant one. Besides causing psychological distress such as irritability, noise can also cause physiological harm, including cardiovascular disease, hypertension, learning disabilities, and hearing loss. Therefore, noise reduction is a significant area of research and has long attracted significant attention. Current noise reduction research focuses on three approaches: controlling the source of noise; controlling the propagation pathways of sound; and protecting the receptors that receive it. The second approach, controlling the propagation pathways of sound, is the most effective. This approach primarily utilizes damping materials to dissipate the energy of sound waves, thereby achieving a noise reduction effect. These damping materials can be categorized by their mechanism of action as sound insulation, sound absorption, and damping materials. Textiles, as a typical porous material, offer significant advantages in sound absorption. The characteristic of porous textile materials is that they have a large number of interconnected pores leading to the surface of the material. When sound waves propagate to the surface of the material, the mechanical energy of the sound waves is converted into kinetic energy of the air inside the component or the component itself. The kinetic energy is then further converted into thermal energy by the viscosity between air and the friction between air and material. Finally, the thermal energy is dissipated through heat transfer, realizing the consumption of sound energy by the porous textile material.

[0003] The principles of current sound-absorbing fabric technology mainly focus on the porous sound absorption mechanism. Sound-absorbing fabrics produced by these technologies often have defects such as insufficient air permeability, complex preparation processes, or a narrow sound absorption range. For example, Chinese invention patent publication number CN109551834B discloses a flame-retardant sound-absorbing curtain decorative fabric. It is a linen base layer, an aramid flame-retardant layer, a polyethylene bubble plastic film sound insulation layer, and an outer layer sewn together with stitches to achieve flame retardancy and sound insulation. However, this design has the problem of the curtain fabric being too thick and not breathable. 108713967A makes ordinary polyester yarn have sound-absorbing function by immersing it in a liquid configured with materials such as pineapple peel cellulose microcrystals / polyaniline composite aerogel microspheres, floating beads, and four-needle zinc oxide whiskers. The treated polyester yarn is blended with glass fiber to obtain curtain fabric with good medium and high frequency sound absorption effect. However, the preparation process uses a variety of chemicals and the water washability is unknown; Chinese invention patent with publication number CN113243739B discloses an anti-ultraviolet sound-absorbing curtain and a preparation method thereof, which is to prepare collagen-modified acrylic fiber by secondary electrospinning, and fill the gaps in the modified acrylic fiber with zirconium dioxide aerogel and polyimide aerogel film, and then prepare the fiber into curtain fabric. The fabric has good UV protection performance, but the preparation process is relatively complicated, the production efficiency is low, and the sound absorption range is limited to the high frequency range.

[0004] In addition to the porous sound absorption mechanism, the consumption or utilization of sound waves can also be achieved by converting sound waves into electrical energy through contact electrification. However, the existing technology based on this principle is mainly aimed at energy collection, rather than sound absorption and noise reduction. Moreover, the product structures produced by the related technology are often large in size and not light and thin in shape, which is not suitable for sound absorption and noise reduction scenarios. For example, the Chinese invention patent application with publication number CN105208497A discloses an acoustic-to-electric conversion device based on friction power generation and its manufacturing method, and the Chinese invention patent with publication number CN112910303B discloses an acoustic friction nanogenerator based on a quarter-wavelength tube, but neither is suitable for application scenarios in home textile accessories.

[0005] In summary, the following problems exist in current sound-absorbing fabrics: (1) Research focuses on fabrics prepared using a single porous sound absorption principle, while there is little research on fabrics prepared using the resonance sound absorption principle or applying dual / multiple energy dissipation mechanisms; (2) The sound absorption frequency range is narrow, mainly concentrated in high frequencies; (3) The preparation process is complicated. Summary of the Invention

[0006] To address the above-mentioned shortcomings in the prior art, the present invention aims to provide a sound-absorbing fabric based on a dual energy dissipation mechanism. This dual energy dissipation mechanism involves converting the mechanical energy of sound waves into kinetic energy, which results in contact electrification of yarns with different electrostatic sequences, enabling charge transfer and converting acoustic energy into electrical energy. It also involves converting acoustic energy into thermal energy, leveraging the fabric's inherent porous structure. This dual energy dissipation mechanism, based on contact electrification of materials by yarn vibration, offers high sound absorption efficiency and a simple manufacturing process. The resulting fabric is lightweight, soft, breathable, and comfortable, capable of absorbing noise of varying frequencies.

[0007] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A sound-absorbing fabric that is electrically charged by contact of materials based on vibration, comprising an upper pile fabric and a lower pile fabric; wherein the upper pile fabric comprises an upper ground tissue unit layer composed of upper ground tissue yarns, an upper consolidation unit layer composed of upper consolidation yarns, and an upper vibration unit layer that is fixed to the upper ground tissue unit layer by the upper consolidation unit layer, wherein the upper vibration unit layer is fixed to the upper ground tissue unit layer at one end and free at the other end, and has an electrostatic sequence of J z , length is l x1 The upper layer is composed of vibrating yarns;

[0009] The lower pile fabric comprises a lower ground tissue unit layer composed of lower ground tissue yarns, a lower consolidation unit layer composed of lower consolidation yarns, and a lower vibration unit layer fixed to the lower ground tissue unit layer by the lower consolidation unit layer, wherein the lower vibration unit layer is fixed to the lower ground tissue unit layer at one end and free at the other end, and has an electrostatic sequence of J. d , length is l x2 The lower layer is composed of vibrating yarns;

[0010] The upper vibration unit layer and the lower vibration unit layer are set up opposite to each other, and the electrostatic sequence J of the upper vibration yarn z Electrostatic sequence J with the underlying vibrating yarn d Different, the distance between the upper and lower organizational unit layers is less than l x1 +l x2 .

[0011] As a first definition of the sound-absorbing fabric of the present invention that is electrified by contact of materials based on vibration, the upper layer of vibrating yarns, the upper layer of consolidating yarns connected thereto, and the upper layer of ground tissue unit layer form an upper layer cantilever beam structure; the lower layer of vibrating yarns, the lower layer of consolidating yarns connected thereto, and the lower layer of ground tissue unit layer form a lower layer cantilever beam structure;

[0012] The upper cantilever beam structure satisfies Formula 1, which is as follows:

[0013]

[0014] Where An is the n-order vibration mode coefficient, f x1n is the nth order resonance frequency of the upper cantilever beam structure, l x1 is the length of the upper vibrating yarn, δ x1 is the linear density of the upper vibrating yarn, R x1 is the bending stiffness of the upper vibrating yarn;

[0015] The lower cantilever beam structure satisfies Formula 2, which is as follows:

[0016]

[0017] Where An is the n-order vibration mode coefficient, f x2n is the nth order resonance frequency of the lower cantilever beam structure, l x2 is the length of the lower vibrating yarn, δ x2 is the linear density of the lower vibrating yarn, R x2 is the bending stiffness of the lower vibrating yarn.

[0018] As a second limitation of the sound-absorbing fabric of the present invention that is electrified by contact of materials based on vibration, the upper vibrating yarns contact and separate from the lower vibrating yarns to generate charge transfer.

[0019] As a third limitation of the present invention, the sound-absorbing fabric that is electrified by contact of materials based on vibration is: x1 The length of the upper vibration yarn is 4 to 250 tex. x1 1~30mm;

[0020] The linear density δ of the lower layer vibrating yarn x2 The length of the lower vibration yarn is 4 to 250 tex. x2 1~30mm;

[0021] The linear density of the upper ground yarn or upper consolidation yarn is 4 to 250 tex;

[0022] The linear density of the lower layer ground yarn or the lower layer consolidation yarn is 4 to 250 tex;

[0023] The surface density of the consolidation points in the upper consolidation unit layer or the lower consolidation unit layer is 49 to 2500 per cm 2 ,

[0024] When the upper ground tissue unit layer or the lower ground tissue unit layer is a woven fabric, its warp density is 280 to 1700 threads / 10 cm, and its weft density is 150 to 1200 threads / 10 cm;

[0025] When the upper ground tissue unit layer or the lower ground tissue unit layer is a knitted fabric, its transverse density is 3 to 85 columns / inch and its longitudinal density is 8 to 105 rows / inch.

[0026] As a fourth limitation of the above-mentioned sound-absorbing fabric based on contact electrification of materials by vibration of the present invention, the upper vibrating yarn and the lower vibrating yarn must be selected in a matching manner, and the matching selection includes one being a dielectric fiber and the other being a conductive fiber, and also includes selecting two materials with different electronegativity from the dielectric fiber;

[0027] The dielectric fiber comprises at least one of polyoxymethylene fiber, polyamide fiber, melamine fiber, wool fiber, silk fiber, cotton fiber, hemp fiber, regenerated cellulose fiber, regenerated protein fiber, polyvinyl alcohol, polyimide fiber, polytetrafluoroethylene fiber, polyvinyl chloride fiber, chlorinated polyvinyl chloride fiber, polypropylene fiber, polyethylene fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, polyester fiber, polyurethane fiber, chloronitrile fiber and polyacrylonitrile fiber;

[0028] The conductive fiber includes at least one of metal conductive fiber, metal-plated fiber, conductive metal compound, conductive fiber, metal complex fiber, carbon conductive fiber and conductive polymer fiber; the conductive layer is coated on the surface of the pressed yarn warp knitted fabric by an impregnation method, a chemical method (in-situ polymerization method, chemical plating method, electrochemical method), a spin coating method, a surface deposition method (polymer vapor deposition, magnetron sputtering, atomic deposition), a printing method (screen printing, inkjet printing), or an electrostatic spinning method; the material of the conductive layer is any one of silver, aluminum, copper, nickel, silver oxide, aluminum oxide, copper oxide and nickel oxide, or a mixture of several thereof;

[0029] The dielectric fibers and conductive fibers may also be various fibers with the same electrical properties obtained by surface processing, or skin-core composite fiber materials with the same electrical properties.

[0030] As a further limitation of the fourth limitation of the above-mentioned sound-absorbing fabric based on vibration-induced material contact electrification of the present invention, the weight of the upper pile fabric or the lower pile fabric is 50 to 1000 g / m 2 .

[0031] The present invention also provides a method for preparing the above-mentioned sound-absorbing fabric based on contact electrification of materials by vibration, the preparation method comprising the following steps performed in sequence:

[0032] S1. Preparation of upper and lower pile fabrics

[0033] Selecting materials with different electrostatic sequences as the materials for the upper and lower vibrating yarns, respectively, and then selecting their linear densities to determine the bending stiffness of the two yarns. The resonant frequencies of the vibrating yarns are then determined based on the noise frequency range. The resonant frequencies of the upper and lower vibrating yarns are then determined based on formulas 1 and 2, thereby determining the lengths of the upper and lower vibrating yarns.

[0034] Select or set respectively: the linear density and material type of the upper ground yarn, the lower ground yarn, the upper consolidation yarn and the lower consolidation yarn, the consolidation point surface density of the upper consolidation unit layer or the lower consolidation unit layer, and the fabric density or weave structure of the upper ground unit layer or the lower ground unit layer;

[0035] Weaving using a weaving machine or a knitting machine to obtain an upper layer pile fabric intermediate and a lower layer pile fabric intermediate;

[0036] The upper and lower pile fabrics are prepared by forming piles of a preset length on the surfaces of the upper and lower pile fabric intermediates through a process of floating pile, spacer fabric cut pile or terry pile.

[0037] S2. Assembly of upper and lower pile fabrics

[0038] The vibration unit layers of the upper and lower pile fabrics are arranged opposite to each other to form a double-layer structure, thereby obtaining the sound-absorbing fabric that generates electrification of materials by contact based on vibration;

[0039] The double-layer structure can be obtained by suspending two layers of pile fabric at a certain distance to form a double-layer structure, or by fixing the two layers of fabric on both sides of a spacer with a certain thickness to form a double-layer structure.

[0040] The spacer is a hard or flexible frame, and the fixing method can be pasting or sewing.

[0041] The present invention also provides the use of the above-mentioned sound-absorbing fabric that generates electrification of materials by contact based on vibration in home textiles.

[0042] As a limitation of the above application of the present invention, when the sound absorbing fabric is applied, an air layer is left between the sound absorbing fabric and the rigid wall;

[0043] The thickness of the air layer is 0 to 500 mm.

[0044] As a further limitation of the above application of the present invention, the thickness of the air layer is Where λ is the wavelength of the sound wave.

[0045] The principle of the present invention is:

[0046] The sound-absorbing fabric, which is based on the contact electrification of materials by vibration, can absorb noise based on a dual energy-consuming sound-absorbing mechanism through a cantilever beam structure and a pore structure. The first energy-consuming mechanism is to convert the mechanical energy of sound waves into kinetic energy based on the principle of contact electrification, so that the upper vibrating yarn and the lower vibrating yarn with different electrostatic sequences are contact-electrified to realize the transfer of charge, thereby converting mechanical energy into electrical energy; the second energy-consuming mechanism is based on the principle of porous sound absorption, and utilizes the pore structure formed by the weaving of yarns in the fabric, and the yarn increases the tortuosity of the pore structure of the fabric, which has a pore viscosity sound-absorbing effect on sound waves and further converts sound energy into heat energy.

[0047] During application, an air layer is left between the sound-absorbing fabric and the rigid wall. The mechanism of improving the sound absorption performance is that the existence of the air layer is equivalent to increasing the thickness of the fabric.

[0048] Due to the use of the above-mentioned sound-absorbing fabric that generates electrification of materials by contact through vibration, the present invention has the following beneficial effects compared with the prior art:

[0049] (1) The present invention provides a sound-absorbing fabric based on vibration-induced material contact electrification. Through ingenious fabric structure design, a sound-absorbing fabric based on yarn vibration-induced material contact electrification is prepared. In the porous sound absorption mechanism, the fabric has an additional way to consume sound energy through the sound-to-electricity conversion mechanism, which is a new sound absorption mechanism and improves the sound absorption effect of the fabric.

[0050] (2) The present invention can design the fabric parameters to make the upper and lower vibrating yarns have different length distributions and different resonant frequencies, thereby achieving the effect of selectively reducing noise at specific frequencies, especially low-frequency noise;

[0051] (3) The sound-absorbing fabric provided by the present invention, which is based on contact electrification of materials by vibration, retains the characteristics of the fabric, such as being light, thin, soft, breathable and comfortable, and having good mechanical properties, and is suitable for use as home textile fabrics such as door curtains and window curtains. In application scenarios, providing an air layer behind the fabric can effectively improve the overall sound absorption effect.

[0052] The preparation method provided by the present invention improves the fabric structure on the basis of existing industrial production of textiles. The process is simple and the cost is low. The existing production equipment and production process are relatively complete, and batch production can be easily achieved.

[0053] The sound-absorbing fabric provided by the present invention, which is based on vibration to cause material contact to generate electricity, can be used to prepare home textile fabrics and also has the potential to be used in friction generators. There is a prospect of further improvement to play its role in the fields of energy and self-driven sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0055] Figure 1 This is a schematic diagram of the overall structure of the sound-absorbing fabric I in Example 1 of the present invention. In the figure: 1-upper pile fabric, 11-upper ground tissue unit layer, 12-upper consolidated unit layer, 13-upper vibration unit layer, 13-1-upper vibration yarn; 2-lower pile fabric, 21-lower ground tissue unit layer, 22-lower consolidated unit layer, 23-lower vibration unit layer, 23-1-lower vibration yarn;

[0056] Figure 2 This is a schematic diagram of the overall structure of the sound-absorbing fabric I applied to a rigid wall in Example 1 of the present invention. In the figure: 1-upper pile fabric layer, 11-upper ground tissue unit layer, 12-upper consolidated unit layer, 13-upper vibration unit layer, 13-1-upper vibration yarn layer; 2-lower pile fabric layer, 21-lower ground tissue unit layer, 22-lower consolidated unit layer, 23-lower vibration unit layer, 23-1-lower vibration yarn layer; 3-air layer, 4-rigid wall;

[0057] Figure 3 This is a diagram showing the sound absorption test results of the sound-absorbing fabric 1 in Example 1 of the present invention;

[0058] Figure 4 Graph showing the sound absorption test results of sound-absorbing fabrics II to VII in Examples 2 to 6 of the present invention and the comparative example. DETAILED DESCRIPTION

[0059] The present invention will be further described in detail below through specific embodiments. It should be understood that the preferred embodiments described herein are only used to illustrate and understand the present invention and are not intended to limit the present invention.

[0060] Unless otherwise specified, the materials and reagents used in the examples of the present invention can be obtained from commercial sources. Experimental methods without specific conditions in the examples are generally performed under conventional conditions or the conditions recommended by the manufacturer.

[0061] Example 1

[0062] This embodiment provides a method for preparing and applying a sound-absorbing fabric that generates electrification of materials through contact through vibration.

[0063] (1) The specific preparation method is as follows:

[0064] For noise frequencies between 100 and 2500 Hz, the fabric's porosity absorbs all frequencies, especially high-frequency noise. Secondly, for low-frequency noise, which is difficult for porous fabrics to absorb and is common in daily life, the vibration of the yarns creates contact electrification in the material to absorb it. To address noise near a certain frequency, the material and linear density of the upper and lower vibrating yarns were first determined, thereby determining the bending stiffness of each yarn.

[0065] The lengths of the upper and lower vibrating yarns are calculated using Formula 1 and Formula 2. Formula 1 and Formula 2 are specifically:

[0066]

[0067] Where An is the n-order mode coefficient, A1=3.516015, A2=22.034490, f x1n is the nth order resonance frequency of the upper cantilever beam structure, l x1 is the length of the upper vibrating yarn, δ x1 is the linear density of the upper vibrating yarn, R x1 is the bending stiffness of the upper vibrating yarn;

[0068]

[0069] Where An is the n-order mode coefficient, A1=3.516015, A2=22.034490, f x2n is the nth order resonance frequency of the lower cantilever beam structure, l x2 is the length of the lower vibrating yarn, δ x2 is the linear density of the lower vibrating yarn, R x2 is the bending stiffness of the lower vibrating yarn.

[0070] Then set the linear density, fabric density, tissue structure and material type of the upper and lower ground yarns of the fabric. Use a weaving machine or a knitting machine for weaving. After weaving, form fluff on the surface of the fabric through a pile cutting process to obtain an upper and lower pile fabric. Finally, assemble the two layers of fabric, set the vibration unit layers of the upper and lower pile fabrics opposite each other, and then form a double-layer structure by hanging the two layers of pile fabric at a certain distance. Alternatively, the two layers of fabric can be fixed on both sides of a hard or flexible frame spacer of a certain thickness by gluing or sewing to form a double-layer structure, so that the spacing between the upper and lower ground tissue unit layers is less than l x1 +l x2 .

[0071] To solve the noise problem near 380Hz and 450Hz, the material and linear density of the upper and lower vibration yarns are selected first. The upper vibration yarn is made of 18texPTFE yarn with a bending stiffness of 3.2×10 - 3 cN·cm 2 The lower vibration yarn is made of nylon yarn with a linear density of 23tex and a bending stiffness of 7.4×10 -3 cN·cm 2 ; Then according to formula 1, when the first-order resonance frequency of the upper vibrating yarn is 380Hz, the yarn length is 4.4mm, and according to formula 2, when the first-order resonance frequency of the lower vibrating yarn is 450Hz, the yarn length is 4.7mm.

[0072] Select: the upper ground yarn, lower ground yarn, upper consolidation yarn, and lower consolidation yarn are 42tex polyester. Set: the upper ground unit layer or the lower ground unit layer is plain weave, the consolidation method of the upper vibrating yarn or the lower vibrating yarn is V-type consolidation, the fabric density is 380 strands / 10cm in warp density and 205 strands / 10cm in weft density; set the yarn surface density of the upper consolidation unit layer and the lower consolidation unit layer to 150 strands / cm 2 Using a weaving machine to weave, the upper layer vibration yarn and the lower layer vibration yarn are respectively fixed to the corresponding ground tissue layer to prepare an upper layer pile fabric intermediate and a lower layer pile fabric intermediate;

[0073] The upper and lower layers of the pile fabric are obtained by cutting the pile with weft floats, and trimming and shearing the pile to make the pile lengths of the upper and lower layers of the pile fabric intermediate (i.e., the lengths of the upper and lower layers of the vibrating yarns) 4.4 mm and 4.7 mm, respectively.

[0074] The measured weight of the upper and lower pile fabrics are 245g / m 2 and 252g / m 2 ;

[0075] The vibration unit layers of the upper and lower fleece fabrics are placed opposite each other, and the two pieces of fabric are respectively pasted on both sides of a 4 mm thick acrylic rectangular frame, with the spacing between the ground tissue unit layers of the two layers of fabric being 4 mm. This yields the sound-absorbing fabric that generates electrification of the material through contact through vibration, which is recorded as sound-absorbing fabric I.

[0076] The structural diagram of the sound-absorbing fabric I is as follows Figure 1 As shown. Figure 1It can be seen that the sound-absorbing fabric I includes an upper layer of fleece fabric 1 and a lower layer of fleece fabric 2; wherein the upper layer of fleece fabric 1 includes an upper layer of ground tissue unit layer 11, an upper layer of consolidation unit layer 12 and an upper layer of vibration unit layer 13 consolidated on the upper layer of ground tissue unit layer 11 by the upper layer of consolidation unit layer 12; the lower layer of fleece fabric 2 includes a lower layer of ground tissue unit layer 21, a lower layer of consolidation unit layer 22 and a lower layer of vibration unit layer 23 consolidated on the lower layer of ground tissue unit layer 21 by the lower layer of consolidation unit layer 22; the upper layer of vibration unit layer 13 and the lower layer of vibration unit layer 23 are arranged opposite to each other.

[0077] Among them, the upper vibration unit layer 13 is composed of an upper vibration yarn 13-1, one end of which is fixed on the upper ground tissue unit layer 12 and the other end is free. The upper vibration yarn 13-1 forms an upper cantilever beam structure with the upper consolidation yarn and the upper ground tissue unit layer 11; the lower vibration unit layer 23 is composed of a lower vibration yarn 23-1, one end of which is fixed on the upper ground tissue unit layer 22 and the other end is free. The lower vibration yarn 23-1 forms a lower cantilever beam structure with the lower consolidation yarn and the lower ground tissue unit 21.

[0078] Because in the upper fleece fabric 1 and the lower fleece fabric 2, the respective consolidation unit layers fix the vibration unit layers and consolidate them with the ground tissue unit layers, complex pore structures and distributions of different sizes and shapes are formed between the yarns of the three unit layers in the upper fleece fabric 1 or the lower fleece fabric 2, and between the layers, which have a pore viscosity sound absorption effect on sound waves, achieving a porous sound absorption effect; in addition, since the electrostatic sequences of the vibrating yarns in the upper fleece fabric 1 and the lower fleece fabric 2 are different, when the upper vibrating yarn 13-1 and the lower vibrating yarn 23-1 come into contact and separation during vibration, charge transfer will occur between the two materials, thereby converting mechanical energy into electrical energy, achieving the yarn vibration contact electrification sound absorption effect.

[0079] (2) Sound absorption effect test

[0080] According to GB / T 18696.2-2002, fabric sound absorption tests were conducted using an impedance tube. The tube's structure is as follows: a speaker is embedded on one side of the tube, whose frequency and power are controlled by computer software; the other side of the tube is a sample tube, which holds the fabric under test. Two sound pressure sensors are placed between the speaker and the fabric. The measured sound pressure values are used to calculate the fabric's sound absorption coefficient using the transfer function method.

[0081] The thickness of the air layer between the sound-absorbing fabric I and the rigid wall is set to 223 mm (the thickness of the air layer is selected based on the following: the sound wave with a frequency of 380 Hz is to be absorbed. According to the wavelength calculation formula, the wavelength λ of the sound wave at 15°C is about 894.7 mm. One quarter of the wavelength is taken, which is 223 mm). The overall structure diagram during measurement is as follows: Figure 2 shown.

[0082] Figure 2 In the figure, 1-upper layer of pile fabric, 11-upper layer of ground tissue unit layer, 12-upper layer of consolidation unit layer, 13-upper layer of vibration unit layer, 13-1-upper layer of vibration yarn; 2-lower layer of pile fabric, 21-lower layer of ground tissue unit layer, 22-lower layer of consolidation unit layer, 23-lower layer of vibration unit layer, 23-1-lower layer of vibration yarn; 3-air layer, 4-rigid wall.

[0083] Sound absorption test results are as follows Figure 3 As shown. Figure 3 It can be seen that within the test range of 100 to 2500 Hz, under the application conditions of this embodiment, the sound absorption coefficient of the sound-absorbing fabric I is 1.000, and sound absorption peaks appear at approximately 380, 450, and 1250 Hz, with peak values of approximately 0.414, 0.550, and 1.000, respectively. The sound absorption peaks at 380 Hz and 450 Hz are related to the vibrations of the upper vibrating yarn 13-1 and the lower vibrating yarn 23-1, and the sound absorption peak at 1250 Hz is related to the sound-absorbing fabric I and the air layer 3 behind it.

[0084] Examples 2 to 5, Comparative Examples

[0085] (I) Examples 2 to 5 and the comparative example are respectively a kind of sound-absorbing fabric based on vibration to make the material contact electrify and its preparation method and application. The sound-absorbing fabric based on vibration to make the material contact electrify is marked as II to VI in sequence. Their preparation methods are basically the same as those of Example 1. The only difference is the raw materials, weaving methods, process parameters and application scenarios. See Table 1 for details. Among them, the difference between Example 2 and Example 1 is that the length of the resonance unit yarn is different.

[0086] Table 1 List of control parameters of Examples 2 to 5 and Comparative Examples

[0087]

[0088]

[0089] (2) Sound absorption effect test

[0090] The sound-absorbing fabrics prepared in Examples 2 to 5 and the comparative example are respectively labeled as sound-absorbing fabric II, sound-absorbing fabric III, sound-absorbing fabric IV, sound-absorbing fabric V, and sound-absorbing fabric VI. The sound absorption coefficients of the six sound-absorbing fabrics within the test range of 100 to 2500 Hz are tested, wherein the testing method is the same as that of Example 1.

[0091] Test results such as Figure 4 As shown. Figure 4As can be seen, the maximum sound absorption coefficient of the sound-absorbing fabric II obtained in Example 2 is 0.997, with sound absorption peaks occurring at approximately 500, 700, and 1000 Hz, with peak values of approximately 0.491, 0.767, and 0.997, respectively. The difference between Example 2 and Example 1 lies in the different yarn lengths of the upper vibrating yarn 13-1 and the lower vibrating yarn 23-1. As can be seen, a decrease in vibrating yarn length increases the natural frequency of the vibrating yarn, shifting the fabric's sound absorption peak toward higher frequencies.

[0092] The difference between Example 3 and Example 1 is that the upper vibrating yarn 13-1 and the lower vibrating yarn 23-1 are made of different materials. The resulting sound-absorbing fabric III has a maximum sound absorption coefficient of 0.993, with a sound absorption peak of 0.993 appearing at approximately 1250 Hz. No sound absorption peaks appear near 380 Hz and 45 Hz. This indicates that the materials of the upper vibrating yarn 13-1 and the lower vibrating yarn 23-1 must be different to ensure a large difference in electronegativity between the two materials. Only then can the resulting sound-absorbing fabric exhibit a sound absorption peak near the resonant frequency of the vibrating yarns.

[0093] The highest sound absorption coefficient of the sound-absorbing fabric IV obtained in Example 4 is 0.996, and sound absorption peaks appear at about 500, 700, and 1000 Hz, with peak values at about 0.450, 0.770, and 0.996, respectively;

[0094] The difference between Example 5 and Example 3 is that the thickness of the air layer 3 between the obtained sound-absorbing fabric and the rigid wall 4 is different. The maximum sound absorption coefficient of the obtained sound-absorbing fabric V is 0.955, and a sound absorption peak of 0.955 appears at 1950 Hz. It can be seen that as the thickness of the air layer 3 decreases, the frequency corresponding to the maximum sound absorption coefficient of the sound-absorbing fabric increases, and the sound absorption peak decreases.

[0095] In the comparative example, the upper vibrating yarn 13-1 and the lower vibrating yarn 23-1 are both made of 15tex nylon conductive yarn with a yarn length of 1.5 mm, the upper ground tissue unit layer 11 and the lower ground tissue unit layer 21 are woven relatively sparsely, the surface density of the consolidation points of the consolidation unit layer is relatively small, and no air layer is reserved when measuring the sound absorption coefficient. The maximum sound absorption coefficient of the final sound-absorbing fabric VI is only 0.674, and no sound absorption peak appears.

[0096] The above results show that by adjusting the yarn type, length, linear density of the upper vibration unit yarn 13-1 and the lower vibration unit yarn 23-1, the density of the ground tissue unit layer, the surface density of the consolidation points of the consolidation unit layer and other parameters, noise of specific frequencies can be reduced, thereby expanding the sound absorption frequency range, especially being able to absorb low-frequency noise well; by setting an air layer behind the fabric, the overall sound absorption effect can be further improved.

[0097] Examples 6 to 10

[0098] Examples 6 to 10 and the comparative example are respectively a sound-absorbing fabric based on vibration-induced material contact electrification, and a preparation method and application thereof. Their preparation methods are basically the same as that of Example 1, and the only differences are the raw materials, weaving methods, process parameters, and application scenarios. See Table 2 for details:

[0099] Table 2 List of control parameters of Examples 6 to 10

[0100]

[0101]

[0102] After testing, it was found that during use, the sound-absorbing fabrics prepared in Examples 6 to 10 had poor sound absorption performance, except for Example 6, in which all variables selected poor solutions, resulting in a maximum sound absorption coefficient of 0.36 and no resonance peak. The sound-absorbing fabrics prepared in Examples 7 to 10 all had good noise absorption effects.

[0103] In other embodiments, the conductive fiber or dielectric fiber can also be at least one of a single-component fiber, a fiber with conductive properties obtained by surface processing, and a sheath-core composite fiber whose sheath contains dielectric fiber or conductive fiber. In addition, the rigid wall is a wall, a glass wall or a metal wall, all of which can achieve the effects of the present invention.

[0104] The sound-absorbing fabric of the present invention, which is based on contact electrification of materials by vibration, retains the characteristics of the fabric such as being light, thin, soft, breathable and comfortable, and having good mechanical properties, and is suitable as fabric for home textile fabrics such as door curtains and window curtains.

Claims

1. A sound-absorbing fabric that electrifies materials through contact based on vibration, characterized in that: The upper pile fabric comprises an upper layer of pile fabric and a lower layer of pile fabric; wherein the upper pile fabric comprises an upper layer of ground tissue unit layer composed of upper layer of ground tissue yarn, an upper layer of consolidation unit layer composed of upper layer of consolidation yarn, and an upper layer of vibration unit layer fixed to the upper layer of ground tissue unit layer by the upper layer of consolidation unit layer, wherein the upper layer of vibration unit layer is fixed to the upper layer of ground tissue unit layer at one end and free at the other end, and has an electrostatic sequence of J z , length is l x1 The upper layer is composed of vibrating yarns; The lower pile fabric comprises a lower ground tissue unit layer composed of lower ground tissue yarns, a lower consolidation unit layer composed of lower consolidation yarns, and a lower vibration unit layer fixed to the lower ground tissue unit layer by the lower consolidation unit layer, wherein the lower vibration unit layer is fixed to the lower ground tissue unit layer at one end and free at the other end, and has an electrostatic sequence of J. d , length is l x2 The lower layer is composed of vibrating yarns; The upper vibration unit layer and the lower vibration unit layer are set up opposite to each other, and the electrostatic sequence J of the upper vibration yarn z Electrostatic sequence J with the lower vibrating yarn d Different, the distance between the upper and lower organizational unit layers is less than l x1 +l x2 .

2. The sound-absorbing fabric according to claim 1, characterized in that: The upper vibrating yarn, the upper consolidating yarn connected thereto and the upper ground tissue unit layer form an upper cantilever beam structure; the lower vibrating yarn, the lower consolidating yarn connected thereto and the lower ground tissue unit layer form a lower cantilever beam structure; The upper cantilever beam structure satisfies Formula 1, which is as follows: Formula 1 Where An is the n-order vibration mode coefficient, f x1n is the nth order resonance frequency of the upper cantilever beam structure, l x1 is the length of the upper vibrating yarn, δ x1 is the linear density of the upper vibrating yarn, R x1 is the bending stiffness of the upper vibrating yarn; The lower cantilever beam structure satisfies Formula 2, which is as follows: Formula 2 Where An is the n-order vibration mode coefficient, f x2n is the nth order resonance frequency of the lower cantilever beam structure, l x2 is the length of the lower vibrating yarn, δ x2 is the linear density of the lower vibrating yarn, R x2 is the bending stiffness of the lower vibrating yarn.

3. The sound-absorbing fabric according to claim 2, characterized in that: The upper vibrating yarn contacts and separates from the lower vibrating yarn, resulting in charge transfer.

4. The sound-absorbing fabric according to claim 2, wherein: The linear density δ of the upper vibrating yarn x1 The length of the upper vibration yarn is 4 to 250 tex. x1 1~30mm; The linear density δ of the lower layer vibrating yarn x2 The length of the lower vibration yarn is 4 to 250 tex. x2 1~30mm; The linear density of the upper ground yarn or upper consolidation yarn is 4 to 250 tex; The linear density of the lower layer ground yarn or the lower layer consolidation yarn is 4 to 250 tex; The surface density of the consolidation points in the upper consolidation unit layer or the lower consolidation unit layer is 49 to 2500 per cm 2 ; When the upper ground tissue unit layer or the lower ground tissue unit layer is a woven fabric, its warp density is 280 to 1700 threads / 10 cm, and its weft density is 150 to 1200 threads / 10 cm; When the upper ground tissue unit layer or the lower ground tissue unit layer is a knitted fabric, its transverse density is 3 to 85 columns / inch and its longitudinal density is 8 to 105 rows / inch.

5. The sound-absorbing fabric according to any one of claims 2 to 4, wherein: The upper layer vibrating yarn and the lower layer vibrating yarn need to be matched. The matching selection includes one of them being a dielectric fiber and the other being a conductive fiber, and also includes selecting two materials with different electronegativity from the dielectric fiber. The dielectric fiber comprises at least one of polyoxymethylene fiber, polyamide fiber, melamine fiber, wool fiber, silk fiber, cotton fiber, hemp fiber, regenerated cellulose fiber, regenerated protein fiber, polyimide fiber, polytetrafluoroethylene fiber, polyvinyl chloride fiber, chlorinated polyvinyl chloride fiber, polypropylene fiber, polyethylene fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, polyester fiber, polyurethane fiber, chloronitrile fiber and polyacrylonitrile fiber; The conductive fiber includes at least one of metal conductive fiber, metal-plated fiber, conductive metal compound fiber, metal complex fiber, carbon-based conductive fiber and conductive polymer fiber.

6. The sound-absorbing fabric for electrifying materials by contact based on vibration according to claim 5, characterized in that: The weight of the upper pile fabric or the lower pile fabric is 50 to 1000 g / m 2 .

7. The method for preparing a sound-absorbing fabric based on contact electrification of materials by vibration according to any one of claims 2 to 6, characterized in that: The preparation method comprises the following steps performed in sequence: S1. Preparation of upper and lower pile fabrics Selecting materials with different electrostatic sequences as the materials for the upper and lower vibrating yarns, respectively, and then selecting their linear densities to determine the bending stiffness of the two yarns. The resonant frequencies of the vibrating yarns are then determined based on the noise frequency range. The resonant frequencies of the upper and lower vibrating yarns are then determined based on formulas 1 and 2, thereby determining the lengths of the upper and lower vibrating yarns. Select or set respectively: the linear density and material type of the upper ground yarn, the lower ground yarn, the upper consolidation yarn and the lower consolidation yarn, the consolidation point surface density of the upper consolidation unit layer or the lower consolidation unit layer, and the fabric density or weave structure of the upper ground unit layer or the lower ground unit layer; Weaving using a weaving machine or a knitting machine to obtain an upper layer pile fabric intermediate and a lower layer pile fabric intermediate; The upper and lower pile fabrics are prepared by forming piles of a preset length on the surfaces of the upper and lower pile fabric intermediates through a process of floating pile, spacer fabric cut pile or terry pile. S2. Assembly of upper and lower pile fabrics The vibration unit layers of the upper and lower pile fabrics are arranged opposite to each other to form a double-layer structure, thereby obtaining the sound-absorbing fabric that generates electrification of materials by contact based on vibration; The double-layer structure can be obtained by suspending two layers of pile fabric at a certain distance to form a double-layer structure, or by fixing the two layers of fabric on both sides of a spacer with a certain thickness to form a double-layer structure. The spacer is a hard or flexible frame, and the fixing method can be pasting or sewing.

8. Use of the sound-absorbing fabric according to any one of claims 1 to 6 in home textiles, wherein the sound-absorbing fabric is electrified by contact of materials based on vibration.

9. The use according to claim 8, characterized in that When the sound-absorbing fabric is used, an air layer is left between the sound-absorbing fabric and the rigid wall; wherein 0 < thickness of the air layer ≤ 500 mm, and the thickness of the air layer is , where λ is the wavelength of the sound wave.

10. The use according to claim 8, characterized in that When the sound absorbing fabric is used, there is no air layer between the sound absorbing fabric and the rigid wall.

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