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

Abstract

The present invention discloses a sound-absorbing fabric based on triboelectrification caused by vibration and a preparation method thereof, belonging to the field of sound-absorbing materials. The sound-absorbing fabric of the present invention is composed of a ground tissue unit layer, a consolidation unit layer, and a vibration unit layer. The three units form a single-layer, double-layer, or multi-layer fabric containing a simply supported beam vibrating string structure or a cantilever beam vibrating arm structure through different preparation methods. At least two materials in the fabric, including the yarn material of the vibration unit, have different electrostatic series. Through contact separation, charge transfer occurs, converting sound energy into electrical energy. At the same time, using the porous structure of the fabric itself, sound energy is converted into heat energy to achieve a multiple sound-absorbing effect. Based on the principle of porous sound absorption, the present invention provides an additional way to consume sound energy through triboelectrification, making the sound-absorbing efficiency of the fabric higher. It can selectively reduce noise at specific frequencies, especially low-frequency noise. The prepared fabric is light, thin, and breathable. The present invention is used as a fabric for curtains, door curtains, door decorations, awning fabrics, or automotive interiors.

Description

Technical Field

[0001] The present invention belongs to the field of sound-absorbing materials, and relates to a sound-absorbing fabric, specifically a sound-absorbing fabric based on triboelectrification caused by vibration and a preparation method thereof. Background Art

[0002] As a typical porous material, textile materials have been widely used in the field of sound-absorbing materials. Due to the large number of interconnected pores inside porous materials that lead to the surface of the material, when sound waves propagate to the surface of the porous material, the mechanical energy of the sound waves is converted into the kinetic energy of the air inside the component or the component itself, and then the kinetic energy is further converted into heat energy through the viscous action between air and air and the frictional action between air and the material, and finally the heat energy is dissipated through heat transfer, realizing the consumption of sound energy by the porous material.

[0003] Currently, the principle of sound-absorbing fabric technology mainly focuses on the porous sound-absorbing mechanism. The sound-absorbing fabrics prepared by these technologies often have defects such as insufficient air permeability or narrow sound-absorbing range. For example, the Chinese invention patent with the publication number CN109551834B discloses a flame-retardant sound-absorbing curtain decorative fabric, which stitches a linen base layer, an aramid flame-retardant layer, a polyethylene bubble plastic film sound-insulating layer, and an outer layer together, and can achieve flame-retardant and sound-insulating effects. However, this design has the problems of too thick curtain fabric and poor air permeability; the Chinese invention patent with the publication number CN113243739B discloses an anti-ultraviolet sound-absorbing curtain and a preparation method thereof, which prepares collagen-modified acrylic fibers by electrospinning twice, fills zirconia aerogel and polyimide aerogel film in the gaps of the modified acrylic fibers, and then prepares the fibers into curtain fabrics. The fabric has good anti-ultraviolet performance, but the preparation process is relatively complicated, the production efficiency is low, and the sound-absorbing range is limited to the high-frequency range.

[0004] In addition to the porous sound-absorbing mechanism, the consumption or utilization of sound waves can also be achieved by converting sound waves into electrical energy through triboelectrification. However, the main purpose of the existing technologies based on this principle is energy harvesting rather than sound absorption and noise reduction, and the structures of the products prepared by the related technologies are often large in size and not thin and light in shape, and are not suitable for sound absorption and noise reduction scenarios. For example, the Chinese invention patent application with the publication number CN105208497A discloses a triboelectric sound-electric conversion device and a manufacturing method thereof, and the Chinese invention patent with the publication number CN112910303B discloses an acoustic triboelectric nanogenerator based on a quarter-wavelength tube, but neither is suitable for the application scenario of home textile ornaments.

[0005] In summary, currently, most sound-absorbing fabrics adopt a single porous sound-absorbing principle, and the sound-absorbing frequency range is narrow, mainly concentrated in the high frequency. The preparation process is complex, and the produced textiles have the problems of heavy and non-breathable fabrics. Summary of the Invention

[0006] To solve the above deficiencies in the prior art, the present invention aims to provide a multi-energy-consuming sound-absorbing fabric, which is based on the conversion of the mechanical energy of sound waves into kinetic energy, enabling the contact electrification of yarn materials with different electrostatic sequences to achieve charge transfer, converting sound energy into electrical energy, and at the same time, based on the porous structure of the fabric itself, converting sound energy into heat energy. The sound-absorbing fabric of the present invention based on the multi-energy-consuming contact electrification caused by yarn vibration has high sound-absorbing efficiency, a simple preparation process, and the prepared fabric is light, thin, soft, breathable and comfortable, and can achieve the purpose of absorbing noises of different frequencies.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows.

[0008] A sound-absorbing fabric based on vibration-induced contact electrification of materials, comprising a ground tissue unit layer composed of ground tissue yarns, a consolidation unit layer composed of consolidation yarns, and a vibration unit layer composed of vibration yarns that vibrate under the action of sound waves;

[0009] The consolidation unit layer is used to connect the vibration unit layer to the ground tissue unit layer, so that the three form a pore structure for the contact and separation electrification of materials.

[0010] This complex pore structure with different sizes and shapes has a pore viscous sound-absorbing effect on sound waves. The pore structure includes the pore structure inherent in the ground tissue unit layer itself and the larger-sized pore structures formed by the consolidation unit layer, the ground tissue unit layer, and the vibration unit layer;

[0011] When the sound-absorbing fabric only contains one piece of fabric, the electrostatic sequences of the vibration yarns and the ground tissue yarns are different. When the sound-absorbing fabric contains at least two pieces of fabric, the electrostatic sequences of the vibration yarns and the ground tissue yarns or another vibration yarn are different. Different electrostatic sequences mean that one is easy to gain electrons and the other is easy to lose electrons, and charge transfer will occur between the two materials when they come into contact and separate;

[0012] The sound-absorbing performance of this sound-absorbing fabric is jointly determined by the contact electrification sound-absorbing effect and the porous sound-absorbing effect, and is specifically determined by the electrostatic sequence difference of the materials, the length and distribution of the vibration unit yarns, the yarn linear density, the fabric density, and the fabric gram weight parameters.

[0013] Preferably, the consolidation unit layer includes multiple consolidation yarns arranged at intervals. The consolidation yarns consolidate the vibration yarns of the vibration unit layer to the ground tissue unit layer and separate them into different lengths, and the three form a simple-supported beam vibration string structure. The distance between the ground tissue unit layer and the vibration unit layer is less than the amplitude of the vibration yarns. The vibration yarns vibrate under the action of sound waves and come into contact with and separate from the ground tissue unit layer to generate charge transfer;

[0014] The simple-supported beam vibration string structure satisfies In the formula, f zjis the resonance frequency of the simply supported beam vibrating string structure, l zjm is the resonance length of the simply supported beam vibrating string structure, δ zj is the linear density of the yarn in the simply supported beam vibrating string structure.

[0015] Preferably, the sound-absorbing fabric includes at least two layers of structures. The way to obtain the double-layer structure includes hanging two layers of structures at a certain distance to form a double-layer structure, and also includes fixing two layers of structures on both sides of a spacer with a certain thickness to form a double-layer structure. At least one layer of the structure is a fabric including a consolidation unit layer with multiple consolidated yarns arranged at intervals and a vibration unit layer with multiple vibrating yarns arranged at intervals. One end of the vibrating yarn is fixed to the ground tissue unit layer of the fabric by the consolidated yarn, and the other end is a free end. The three form a cantilever beam vibration structure. The vibrating yarn is in an interdigitated relationship with another layer of fabric. The distance between the ground tissue unit layers of the two layers of fabric is less than the length of the vibrating yarn. The free end of the vibrating yarn vibrates and contacts and separates from another layer of fabric to generate static electricity and produce charge transfer;

[0016] The cantilever beam vibration arm structure satisfies where f zx is the resonance frequency of the cantilever beam vibration arm structure, l zx is the resonance length of the cantilever beam vibration arm structure, δ zx is the linear density of the yarn in the cantilever beam vibration arm structure.

[0017] Preferably, the linear density of the ground tissue yarn is 4-250 tex;

[0018] The density of the consolidated yarn is 50-1000 pieces / 10 cm, and the linear density is 5-250 tex;

[0019] The length of the vibrating yarn is 1-200 mm, and the linear density is 3-250 tex.

[0020] Preferably, the gram weight of the sound-absorbing fabric is 50-1000 g / m 2 ;

[0021] The warp density of the ground tissue unit layer is 280-1700 pieces / 10 cm, and the weft density is 150-1200 pieces / 10 cm;

[0022] The horizontal density of the knitted fabric of the ground tissue unit layer is 3-85 rows / inch, and the vertical density is 8-105 rows / inch.

[0023] Preferably, the raw materials of the formed ground yarns and vibration yarns are two or more materials selected from conductive fibers or dielectric fibers; the conductive fibers or dielectric fibers are at least one of single-component fibers, fibers with conductive properties obtained by surface processing, and core-sheath composite fibers with a dielectric fiber or conductive fiber in the cortex.

[0024] Preferably, the dielectric fibers include at least one of polyoxymethylene fibers, polyamide fibers, melamine fibers, wool fibers, silk fibers, cotton fibers, hemp fibers, regenerated cellulose fibers, regenerated protein fibers, polyvinyl alcohol, polyimide fibers, polytetrafluoroethylene fibers, polyvinyl chloride fibers, chlorinated polyvinyl chloride fibers, polypropylene fibers, polyethylene fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyester fibers, polyurethane fibers, nitrile chloroprene fibers, and polyacrylonitrile fibers.

[0025] Preferably, the conductive fibers include at least one of metal conductive fibers, metal-coated fibers, conductive metal compound conductive fibers, metal complex fibers, carbon-based conductive fibers, and conductive polymer fibers.

[0026] Preferably, the sound-absorbing fabric further includes an air layer, and the thickness of the air layer is 0 - 500 mm.

[0027] The present invention also provides a preparation method of a sound-absorbing fabric that generates static electricity by material contact based on vibration. The sound-absorbing fabric is at least one of single-layer fabrics, spacer fabrics, double-layer fabrics, and multi-layer fabrics formed integrally or processed step by step by weaving, knitting, non-woven, braiding, or sewing methods.

[0028] Among them, integral molding is to directly obtain a sound-absorbing fabric that generates static electricity by material contact based on vibration and simultaneously includes a ground tissue unit layer, a vibration unit layer, and a consolidation unit layer in one step;

[0029] Step-by-step processing is to first prepare the structure of one or two of the ground tissue unit layer, the vibration unit layer, and the consolidation unit layer, and then combine them to form a sound-absorbing fabric that generates static electricity by material contact based on vibration.

[0030] The principle of the present invention is:

[0031] The fabric of the present invention is composed of a ground weave unit layer, a vibration unit layer, and a consolidation unit layer made of different yarns. The three structural units form two structures that interact with sound waves, enabling multiple energy dissipation and sound absorption: First, due to the existence of the three structural units, the porous structure of the fabric itself increases the tortuosity of the fabric pore structure, improving the sound absorption performance of the porous structure; Second, the vibration structure composed of the ground weave unit layer and the vibration unit layer is divided into a simply supported beam vibration string structure with both ends fixed by the consolidation unit and a cantilever beam vibration arm structure with only one end fixed by the consolidation unit. Under the action of sound waves, it vibrates and makes contact with and separates from the ground weave unit layer composed of yarns with different electrostatic sequences, realizing the transfer of charges, converting sound energy into electrical energy, and increasing the consumption channels of sound energy.

[0032] (I) Structures and requirements of the three unit layers

[0033] The sound-absorbing fabric of the present invention is composed of a ground weave unit layer, a vibration unit layer, and a consolidation unit layer made of different yarns. The structural requirements of the three unit layers are as follows:

[0034] 1) Ground weave unit layer

[0035] As the base, the ground weave unit layer provides support for the consolidation unit layer and the vibration unit layer on the one hand, and on the other hand, as a porous material itself, it can also increase the sound absorption performance of the overall structure. When the ground weave unit layer and the vibration unit layer undergo periodic contact and separation, the greater the difference in their electrostatic sequences, the easier it is to transfer charges, thereby consuming more sound energy.

[0036] 2) Vibration unit layer

[0037] The function of the vibration unit layer is to vibrate under the action of external sound wave forces, make relative motion with the ground weave unit layer, and make contact and separation with the ground weave unit layer. The existence state of a certain yarn material in the vibration unit layer is divided into two types: one is that both ends of the yarn material are fixed, and the other is that one end of the yarn material is fixed and the other end is free. The vibration of the former is similar to that of a simply supported beam structure, and the latter is similar to that of a cantilever beam structure. When the vibration unit layer resonates, the greater its movement amplitude, the more intense the contact and separation effect, and the greater the consumption of sound energy. Therefore, by designing the resonance frequency and distribution of the vibration unit layer, the sound absorption frequency band of the fabric can be broadened.

[0038] 2.1) Vibration unit layer based on simply supported beam vibration string structure

[0039] The yarn fixed at both ends can be regarded as a simply supported beam vibration string structure. Assume that there is a yarn with a total length of l zj and a linear density of δ zj, a yarn with a certain elasticity, fixed at both ends and tensioned, which can be regarded as a string. Among them, due to the organizational structure design, there are multiple fixed nodes on the yarn and it is divided into vibration unit layers with lengths of l zj1 , l zj2 , l zj2 ......l zjm . After being excited by sound waves, the vibration unit layer undergoes string vibration under the action of tension T zj . The vibration direction is perpendicular to the length direction of the yarn, and its natural frequency equation is

[0040]

[0041] In the formula, f zjn is the nth-order resonance frequency of the simply supported beam vibrating string structure; l zjm is the resonance length of the simply supported beam vibrating string structure; T zj is the tension at both ends of the yarn; δ zj is the linear density of the yarn.

[0042] When n = 1, the simply supported beam undergoes the first-order resonance. Compared with the second, third, fourth... order resonances, this resonance has the following two characteristics:

[0043] First, the corresponding resonance amplitude is the largest, which means that the vibrating unit yarn in the fabric can have a larger friction area with other materials;

[0044] Second, the corresponding resonance frequency is the smallest, which means the lowest frequency at which the vibrating unit yarn can resonate.

[0045] In noise control, low-frequency noise is often more difficult to solve. The large amplitude and low frequency at the first-order resonance are the optimal choices, so n = 1 is selected.

[0046] In addition, during the weaving process, the yarn tension is controlled, and after leaving the loom, the tension of the vibrating yarn in the fabric basically remains at a value. Therefore, T zj can be regarded as a constant.

[0047] In summary, the relationship between the vibration unit length and linear density and their resonance frequency can be obtained as

[0048] 2.2) Vibration unit layer based on the vibrating arm structure of a cantilever beam

[0049] A beam with a fixed support at one end and a free end at the other end is a cantilever beam. In the fabric, a yarn fixed at one end on the base fabric and free at the other end with shear and bending resistance can be regarded as a vibrating arm structure of a cantilever beam. Let the length of the vibrating arm structure of the cantilever beam be l zx , and the linear density be δ zx , then its natural frequency equation is

[0050]

[0051] In the formula, f zxn is the nth-order resonance frequency of the cantilever beam vibrating arm structure; A n is the nth-order vibration mode coefficient, A1 = 3.516015, A2 = 22.034490...; l zx is the length of the cantilever beam vibrating arm structure; R zx is the flexural rigidity of the cantilever beam; δ zx is the linear density of the yarn in the cantilever beam vibrating arm structure.

[0052] The reason for taking n = 1 for the resonance of the simply supported beam structure in subsection 2.2) is the same. In the resonance of the cantilever beam vibrating arm structure, n = 1 is also taken.

[0053] In the fabric, R zx is a parameter related to the material and linear density of the vibrating yarn, and it is not a parameter that can be arbitrarily selected. For conventional yarns, R zx can be obtained by looking up, and thus it can be regarded as a constant. For non-conventional yarns, this value can be obtained by testing after selecting the vibrating yarn material and linear density. Therefore, when selecting the parameters related to the resonance frequency of the vibrating yarn, R zx is regarded as a passively obtained value, rather than a variable. Thus,

[0054] 3) Consolidation unit layer

[0055] In the simply supported beam vibrating string structure, the role of the consolidation unit layer is to fix the vibrating unit layer on the ground tissue unit layer; in the cantilever beam vibrating arm structure, the consolidation unit layer fixes one end of the vibrating unit layer on the ground tissue unit layer.

[0056] (2) Two kinds of sound absorption and energy dissipation mechanisms

[0057] Based on the conversion of acoustic energy into heat energy in porous materials, combined with the sound absorption principle of charge transfer generated by the contact separation of different electrical sequence materials due to yarn vibration, through textile processing technology, the present invention prepares a sound absorption fabric based on vibration-induced contact electrification and its preparation method.

[0058] 1) Contact electrification sound absorption mechanism

[0059] 1.1) Prerequisites for vibration

[0060] The prerequisite for vibration is the need for external force excitation. As a mechanical external force, sound waves can excite substances to vibrate. When sound waves propagate in a fluid medium, they are longitudinal waves. That is, when sound waves propagate in the air, the vibration direction of the particles is the same as the sound propagation direction. Therefore, when sound waves propagate to the surface of a sample, a pressure effect will be generated on the sample.

[0061] 1.2) Contact-separation structure

[0062] It includes three parts: the ground tissue unit layer, the vibration unit layer, and the consolidation unit layer. To ensure contact separation and charge transfer between materials, the contact-separation structure needs to meet the following points:

[0063] (1) The vibration unit layer vibrates under the action of sound waves;

[0064] (2) The distance between the vibration unit layer and the material where contact separation is expected to occur is less than the amplitude of the yarn vibration;

[0065] (3) The materials of the vibration unit layer and the ground tissue unit layer should have different electrical sequences, and the greater this difference, the better.

[0066] 1.3) Contact electrification sound absorption principle and its influencing factors

[0067] The contact electrification effect is an electrification effect triggered by contact. That is, during the process of contact separation between one material and another material, the two materials will carry opposite charges, and the sign of the charge carried by the material depends on the relative polarity between the contacting materials. Therefore, for two materials that undergo contact separation under sound wave vibration, if materials with different electrostatic sequences are used, charges will be generated. Thus, the mechanical energy of the sound wave is converted into electrical energy, resulting in energy loss.

[0068] Furthermore, a fabric is composed of thousands of yarns. Through different organizational structures, a macroscopic stable structure and a vibratable structure between the yarns can be achieved. Each individual yarn with a different electrical sequence in the fabric constitutes a micro-nano triboelectric generator, and thousands of micro-nano power generation systems will macroscopically achieve the loss of sound waves and realize sound absorption.

[0069] The sound absorption performance of triboelectrification in the fabric is determined by the contact area between the vibration unit layer and the ground tissue unit layer and the difference in the electrostatic series between the two materials. Among them, the linear density of the ground tissue yarn, the density of the ground tissue yarn, the gram weight of the ground tissue unit layer, the linear density of the vibration yarn, and the density of the vibration yarn jointly determine the contact area between the two. The lower the linear density of the ground tissue yarn, the higher the density of the ground tissue yarn, the greater the gram weight of the ground tissue unit layer, the greater the linear density of the vibration yarn, and the greater the density of the vibration yarn, the larger the contact area. The electrostatic series of the ground tissue yarn and the electrostatic series of the vibration yarn determine the difference in the electrostatic series between the two. The larger the contact area and the more obvious the difference in the electrostatic series, the more charge transfer occurs between the vibration yarn and the ground tissue yarn, that is, the more sound energy is consumed.

[0070] 2) Sound absorption principle of porous structure

[0071] Porous materials are characterized by a large number of interconnected pores that lead to the surface of the material inside. When sound waves propagate to the surface of the porous material, the sound waves penetrate the porous material and propagate inside the material. The mechanical energy of the sound waves is converted into the kinetic energy of the air or the component itself inside the component, and then the kinetic energy is further converted into heat energy through the viscous action between the air and the friction between the air and the material, and finally the heat energy is dissipated through heat transfer, realizing the consumption of sound energy by the porous material. Correspondingly, the porous sound-absorbing fabric should also consist of a considerable number of pores, and the pore characteristics such as the geometric shape of these pores, the pore size, and the opening shape connecting the pores will affect the sound absorption performance of the material. Compared with porous materials with a uniform structure, materials with different pore structures are beneficial to increasing the tortuosity of the material and increasing the propagation path of sound waves inside the material, thereby increasing the consumption of sound energy. The present invention includes the pore structure inherent in the ground tissue unit layer fabric itself, the pore structure with a larger size formed by the consolidation unit layer, the ground tissue unit layer, and the vibration unit layer, and the slender pore structure with a chord length formed between the vibration unit layer and the ground tissue unit layer. The three are organically combined to form a complex pore structure.

[0072] The pore structure of the fabric is jointly determined by the density of the consolidation yarn, the linear density of the consolidation yarn, the linear density of the vibration yarn, the linear density of the ground tissue yarn, the density of the ground tissue yarn, and the gram weight of the ground tissue unit layer, and there are optimal parameters. If the ground tissue is a non-woven material, its pore structure is also related to the yarn arrangement.

[0073] Due to the adoption of the above technical solutions, compared with the prior art, the beneficial effects obtained by the multi-energy-consuming sound-absorbing fabric based on yarn vibration for triboelectrification of the present invention are:

[0074] (1) The triboelectrification principle adopted in the present invention is a novel sound absorption mechanism. Through the design of the fabric structure, multiple energy dissipation paths are realized. On the basis of the porous sound absorption principle, through the sound-electricity conversion mechanism, the fabric has an additional path to consume sound energy, improving the sound absorption effect of the fabric;

[0075] (2) Through the design of fabric parameters, the resonant strings have different length distributions and different resonant frequencies, achieving the effect of selectively reducing noise at specific frequencies, especially the noise at low frequencies;

[0076] (3) The preparation process adopted in the present invention is simple, with low cost and easy to realize batch production;

[0077] (4) The sound-absorbing fabric prepared in the present invention retains the characteristics of the fabric such as being light, thin, soft, breathable, comfortable, and having good mechanical properties, and is suitable as home textile fabrics such as curtains;

[0078] (5) In the application scenario, setting an air layer behind the fabric can effectively improve the overall sound absorption effect;

[0079] (6) The fabric designed in the present invention has the potential to be used as a triboelectric generator and can be further improved to play its application in the fields of energy and self-powered sensors. Description of the Drawings

[0080] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0081] Figure 1 It is a longitudinal sectional view of the multi-energy dissipation sound-absorbing fabric based on the vibration of the yarn in the form of a simply supported beam to make the material triboelectrify in Embodiment 1. In the figure: 1. Ground tissue unit layer; 2. Consolidation unit layer; 3. Vibration unit layer;

[0082] Figure 2 It is a longitudinal sectional view of the multi-energy dissipation sound-absorbing fabric based on the vibration of the yarn in the form of a cantilever beam to make the material triboelectrify in Embodiment 2. In the figure: 4. Lower ground tissue unit layer; 5. Consolidation unit layer; 6. Vibration unit layer; 7. Upper ground tissue unit layer;

[0083] Figure 3 It is a longitudinal sectional view of the multi-energy dissipation sound-absorbing fabric based on the vibration of the yarn in the form of a cantilever beam to make the material triboelectrify in Embodiment 3. In the figure: 8. Lower fabric ground tissue unit layer; 9. Lower fabric consolidation unit layer; 10. Lower fabric vibration unit layer; 11. Upper fabric ground tissue unit layer; 12. Upper fabric consolidation unit layer; 13. Upper fabric vibration unit layer; 14. Intermediate layer spacer separating the upper and lower fabrics. Detailed Embodiments

[0084] 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 for the purpose of illustrating and understanding the present invention, and are not intended to limit the present invention.

[0085] The materials, reagents, etc. used in the embodiments of the present invention can be obtained from commercial sources without special instructions. The experimental methods without specific conditions in the embodiments are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer.

[0086] Example 1 An acoustic fabric based on triboelectrification by vibration and its preparation method

[0087] This embodiment is an acoustic fabric based on triboelectrification by vibration and its preparation method, including a ground tissue unit layer composed of ground tissue yarns, a consolidation unit layer composed of consolidation yarns, and a vibration unit layer composed of vibration yarns that vibrate under the action of sound waves; the consolidation unit layer is used to connect the vibration unit layer to the ground tissue unit layer, so that the three form a pore structure for triboelectrification by contact separation of materials; the vibration unit layer selects a simply supported beam vibrating string structure, and its structure satisfies

[0088] A single-layer warp-knitted press yarn knitted fabric is prepared in an integral molding manner, where the linear density of the ground tissue yarn is 37 tex, the density of the consolidation yarn is 60 pieces / 10 cm, the linear density is 50 tex, the length of the vibration yarn is 15 mm, and the linear density is 25 tex; the transverse density of the knitted fabric is 53 columns / inch, the longitudinal density is 70 rows / inch, and the gram weight of the fabric is 170 g / cm 2 ; According to the different electrostatic sequences of the ground tissue yarn and the vibration yarn, the ground tissue yarn selects dielectric fibers, specifically a blended yarn of cotton fiber and polyamide fiber; the vibration yarn selects conductive fibers, specifically stainless steel conductive fibers; the three units are made into a fabric through a knitting process, specifically woven by a warp knitting machine. When knitting, the ground tissue unit layer is knitted by a ground comb, the consolidation layer is double-yarn knitted with the ground tissue unit layer together using a special yarn guide, and the press yarn comb is threaded according to the arrangement of the consolidation yarn and cooperates with the press plate to knit the vibration unit yarn; a single-layer warp-knitted press yarn knitted fabric is obtained and marked as Z1.

[0089] The longitudinal sectional schematic diagram of the fabric obtained in this embodiment is as Figure 1As shown in the figure, it includes a ground tissue unit layer 1, a consolidation unit layer 2, and a vibration unit layer 3. Among them, the consolidation unit layer 2 connects the vibration unit layer 3 to the ground tissue unit layer 1, so that the three form a pore structure for triboelectrification by contact separation of materials. The consolidation unit layer 2 includes a plurality of consolidation yarns arranged vertically at intervals. One end of the consolidation yarn is fixed to the ground tissue unit layer 1, and the other end is fixed to the vibration unit layer 3. The adjacent two consolidation yarns and the connected vibration yarns form a simply supported beam vibration string structure. The ground tissue unit layer 1 and the vibration unit layer 3 generate charge transfer through triboelectrification by contact separation of the simply supported beam vibration string structure.

[0090] Example 2: A sound-absorbing fabric based on triboelectrification by vibration and its preparation method

[0091] This example is a sound-absorbing fabric based on triboelectrification by vibration and its preparation method, including a ground tissue unit layer composed of ground tissue yarns, a consolidation unit layer composed of consolidation yarns, and a vibration unit layer composed of vibration yarns that vibrate under the action of sound waves. The consolidation unit layer is used to connect the vibration unit layer to the ground tissue unit layer, so that the three form a pore structure for triboelectrification by contact separation of materials. The vibration unit layer selects a cantilever beam vibration arm structure, and its structure satisfies

[0092] A double-layer velvet-to-hole sound-absorbing fabric is prepared by a step-by-step processing method. The preparation method is as follows: First, a flocked fabric is prepared. The flocked fabric and a layer of mesh fabric are suspended at intervals, and the fluff of the flocked fabric is inserted into the pores of the mesh fabric. Among them, the linear density of the ground tissue yarn of the flocked fabric is 32 tex, the density of the consolidation yarn is 150 per 10 cm, the linear density is 32 tex, the length of the vibration yarn is 5 mm, and the linear density is 20 tex. The gram weight of the flocked fabric is 210 g / cm 2 , the warp density is 280 per 10 cm, and the weft density is 150 per 10 cm; the linear density of the ground tissue yarn of the mesh fabric is 12 tex, and the gram weight of the fabric is 250 g / cm 2 , the horizontal density is 21 columns per inch, and the vertical density is 66 rows per inch; the fluff yarn of the flocked fabric selects a dielectric fiber that is easy to lose charge, specifically nylon multifilament; the ground tissue yarn of the mesh fabric selects a dielectric fiber that is easy to obtain charge, specifically PTFE multifilament; the double-layer velvet-to-hole sound-absorbing fabric is prepared by weaving and knitting processing methods. Specifically, the flocked fabric is woven into a cut pile fabric by a weaving machine, and the mesh fabric is woven by a knitting method. The assembled sound-absorbing fabric is marked as Z2.

[0093] The longitudinal sectional schematic diagram of the prepared fabric is as Figure 2As shown in the figure, it includes a lower fabric unit layer 4, a consolidation unit layer 5, a vibration unit layer 6, and an upper fabric unit layer 7. One end of the vibration unit layer 6 is fixed to the lower fabric unit layer 4 of the sound-absorbing fabric by the consolidation unit layer 5, and the other end is a free end. The three form a cantilever beam vibration structure, and the vibration unit layer 6 is in an inserted relationship with the upper fabric unit layer 7 of another layer of fabric.

[0094] Example 3: A sound-absorbing fabric based on triboelectrification by vibration and its preparation method

[0095] This example is a sound-absorbing fabric based on triboelectrification by vibration and its preparation method, which includes three layers of fabric. One layer of fabric serves as an intermediate layer to play a spacing role, and the remaining two layers of fabric include a lower fabric unit layer composed of ground tissue yarns, a consolidation unit layer composed of consolidation yarns, and a vibration unit layer composed of vibration yarns that vibrate under the action of sound waves. The consolidation unit layer is used to connect the vibration unit layer to the lower fabric unit layer, so that the three form a pore structure for triboelectrification by contact separation of materials. The vibration unit layer selects a cantilever beam vibration arm structure, and its structure satisfies

[0096] Prepare a multi-layer raised fabric by a step-by-step processing method. The preparation method is as follows: First, prepare two raised fabrics, then arrange the piles of the two raised fabrics opposite to each other and interlace the fluff with each other. Place a non-woven fabric strip in the middle of the two raised fabrics to separate the raised fabrics, and finally sew the three layers of fabric together by sewing. The linear density of the ground tissue yarns of one layer of raised fabric is 32 tex, the density of the consolidation yarns is 150 per

[0097] / 10 cm, the linear density is 32 tex, the length of the vibration yarn is 5 mm, the linear density is 20 tex, the warp density of the lower fabric unit layer is 280 per 10 cm, the weft density is 150 per 10 cm, and the gram weight is 210 g / cm 2 ; The linear density of the ground tissue yarns of the other layer of raised fabric is 32 tex, the density of the consolidation yarns is 150 per 10 cm, the linear density is 32 tex, the length of the vibration yarn is 5 mm, the linear density is 50 tex, the warp density of the lower fabric unit layer is 280 per 10 cm, the weft density is 150 per 10 cm, and the gram weight is 250 g / cm 2; For the previous flocked fabric, dielectric fibers that are prone to losing charge are selected for the yarns, specifically polyamide multifilaments; for the latter flocked fabric, dielectric fibers that are prone to gaining charge are selected for the vibrating yarns, specifically PVDF monofilaments; the three units are made into a fabric through a weaving process, specifically woven on a weaving machine. Two groups of warp and weft yarns are interwoven in a plain weave to form upper and lower base fabrics, and the vibrating yarns connect the upper and lower base fabrics. After leaving the loom, the upper and lower base fabrics are cut by the blades of a flocking machine to obtain the flocked fabric. The two flocked fabrics are combined with their nap surfaces facing each other, separated by a commercially available non-woven fabric strip with a thickness of 5 mm in the middle, and the three are fused into a whole by sewing. The obtained sound-absorbing fabric is marked as Z3.

[0098] The schematic longitudinal section diagram of the fabric obtained in this embodiment is as Figure 3 shown, including a lower fabric ground tissue unit layer 8, a lower fabric consolidation unit layer 9, a lower fabric vibration unit layer 10, an upper fabric ground tissue unit layer 11, an upper fabric consolidation unit layer 12, an upper fabric vibration unit layer 13, and an intermediate layer spacer 14 separating the upper and lower fabrics; among them, one end of the lower fabric vibration unit layer 10 is fixed to the lower fabric ground tissue unit layer 8 of the fabric by the lower fabric consolidation unit layer 9, and the other end is a free end. The three units form a cantilever beam vibration structure; one end of the upper fabric vibration unit layer 13 is fixed to the upper fabric ground tissue unit layer 11 of the fabric by the upper fabric consolidation unit layer 12, and the other end is a free end. The three units form a cantilever beam vibration structure; the free end of the lower fabric vibration unit layer 10 and the free end of the upper fabric vibration unit layer 13 are in an inserted relationship.

[0099] Examples 4 - 7 Sound-absorbing Fabrics Based on Electrostatic Charging by Vibration

[0100] Examples 4 - 7 are respectively a kind of sound-absorbing fabric based on electrostatic charging by vibration. Their contents are basically the same as those of Examples 1 and 2, except for the selected substances and parameters. See Table 1 for details:

[0101] Table 1 Method Parameter Table for Examples 4 - 7

[0102]

[0103]

[0104] Effect Experiment

[0105] Select a commercially available fabric with noise reduction function as the control group, marked as D1, and select the sound-absorbing fabrics Z1 - Z7 obtained in Examples 1 - 7 as the experimental group to conduct the following sound-absorbing performance effect experiment.

[0106] The fabrics of the experimental group and the control group were respectively placed in an impedance tube for sound absorption performance experiments. The structure of the impedance tube is as follows: a loudspeaker is embedded on one side of the impedance tube, and the sound frequency and power of the loudspeaker are controlled by computer software; the other side of the impedance tube is a specimen tube where the fabric to be measured can be placed; two sensors for detecting sound pressure are placed between the loudspeaker and the fabric, and the measured sound pressure value can be used to calculate the sound absorption coefficient of the fabric according to the transfer function method. Since the average sound absorption coefficient is a recognized index for evaluating sound absorption performance, the average sound absorption coefficient is used to represent the sound absorption performance of the material. The average sound absorption coefficient refers to the average value obtained from the sound absorption values of different octave bands. If the sound absorption coefficients of each frequency band are α1, α2, ……, α n , then the average sound absorption coefficient can be expressed as: α = (α1 + α2 +...... + α n ) / n. Calculate the average sound absorption coefficient in the range of 100 Hz to 6300 Hz through this formula. Since a sound absorption coefficient greater than 0.2 is considered to have a sound absorption effect, the frequency range where the sound absorption coefficient of the fabric is greater than 0.2 was sorted out, as shown in Table 2:

[0107] Table 2 Sound Absorption Performance Experiment

[0108]

[0109] From the experimental results of the above average sound absorption coefficient, sound absorption frequency range, and sound absorption peak position, it can be seen that the average sound absorption coefficients of the experimental groups Z1 to Z7 are all higher than those of the control group, indicating that the sound absorption fabric of the present invention based on triboelectrification by vibration has a better sound absorption effect.

[0110] In the experimental group, Z1, Z4, and Z5 are single-layer fabrics. Z4 and Z1 are basically the same in other conditions, only the yarn materials of the ground yarn and the vibration yarn are different. In Z4, materials with close electronegativity come into contact, while in Z1, materials with a large difference in electronegativity come into contact. The result shows that there is a sound absorption peak in Z1, which is caused by yarn resonance and triboelectricity generation between different materials. Since the electronegativity of the friction materials in Z4 is close, the existence of a sound absorption peak cannot be observed, indicating that the greater the difference in electronegativity between two materials in the electrostatic series, the better the sound absorption effect, and the charge transfer caused by material contact has a promoting effect on sound absorption. Z5 and Z1 are basically the same in other conditions, only the length of the vibration yarn is different. The length of the vibration yarn in Z5 is greater than that in Z1. From the experimental results of the sound absorption frequency range and the sound absorption peak position, it can be seen that as the length of the vibration yarn increases, the sound absorption frequency range and the sound absorption peak position of the sound absorption fabric shift to lower frequencies.

[0111] Z2 and Z3 are double-layer or multi-layer fabrics. From the experimental results, it can be seen that double-layer or multi-layer fabrics can improve the sound absorption performance of the fabric.

[0112] Z6 and Z7 are spacer fabrics. Other conditions of the two are basically the same, except that when Z7 is applied, an air layer is reserved between the fabric and the rigid wall. It can be seen from the experimental results that the existence of the air layer can improve the sound absorption performance of the fabric.

[0113] Table 3 Method Parameter Table of Examples 8 - 11

[0114]

[0115]

[0116]

[0117] After detection, during the use process, the sound-absorbing fabrics Z8 - Z11 prepared in Examples 8 - 11 can all produce good effects on noise absorption.

[0118] It should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the above embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the above embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An acoustic fabric that generates triboelectricity by vibration, characterized in that, It includes a ground weave unit layer composed of ground weave yarns, a consolidation unit layer composed of consolidation yarns, and a vibration unit layer composed of vibration yarns that vibrate under the action of sound waves; the consolidation unit layer is used to connect the vibration unit layer to the ground weave unit layer, so that the three form a pore structure for triboelectrification by material contact and separation. When the sound-absorbing fabric only contains one piece of fabric, the electrostatic series of the vibration yarns and the ground weave yarns are different. When the sound-absorbing fabric contains at least two pieces of fabric, the electrostatic series of the vibration yarns and the ground weave yarns or another kind of vibration yarns are different.

2. The sound-absorbing fabric for triboelectrification of materials based on vibration according to claim 1, wherein The consolidation unit layer includes multiple consolidation yarns arranged at intervals. The consolidation yarns consolidate the vibration yarns of the vibration unit layer to the ground weave unit layer and separate them into different lengths, and the three form a simply supported beam vibrating string structure. The vibration yarns vibrate under the action of sound waves and contact and separate from the ground weave unit layer to generate triboelectrification and charge transfer. The simply supported beam vibrating string structure satisfies where f zj is the resonance frequency of the simply supported beam vibrating string structure, l zjm is the resonance length of the simply supported beam vibrating string structure, and δ zj is the linear density of the yarn in the simply supported beam vibrating string structure.

3. The sound-absorbing fabric for triboelectrification of materials based on vibration according to claim 1, wherein The sound-absorbing fabric includes at least two layers of structures. The double-layer structure can be obtained by suspending the two layers at a certain distance to form a double-layer structure, or by fixing the two layers on both sides of a spacer with a certain thickness to form a double-layer structure. At least one layer of the structure is a fabric including a consolidation unit layer with multiple consolidation yarns arranged at intervals and a vibration unit layer with multiple vibration yarns arranged at intervals. One end of the vibration yarns is fixed to the ground weave unit layer of the fabric by the consolidation yarns, and the other end is a free end. The three units form a cantilever beam vibration structure. The vibration yarns are in an interdigitated relationship with the other layer of fabric. The distance between the ground weave unit layers of the two layers of fabric is less than the length of the vibration yarns. The free ends of the vibration yarns vibrate and contact and separate from the other layer of fabric to generate triboelectrification and charge transfer. The cantilever vibration arm structure satisfies where f zx is the resonance frequency of the cantilever vibration arm structure, l zx is the resonance length of the cantilever vibration arm structure, and δ zx is the linear density of the yarn in the cantilever vibration arm structure.

4. The sound-absorbing fabric for triboelectrification based on vibration according to any one of claims 1 to 3, characterized in that The linear density of the ground weave yarns is 4 to 250 tex; The density of the consolidation yarns is 50 to 1000 per 10 cm, and the linear density is 5 to 250 tex; The length of the vibration yarns is 1 to 200 mm, and the linear density is 3 to 250 tex; The grammage of the sound-absorbing fabric is 50 to 1000 g / m 2 ; The warp density of the ground weave unit layer is 280 to 1700 per 10 cm, and the weft density is 150 to 1200 per 10 cm; The horizontal density of the knitted fabric of the ground weave unit layer is 3 to 85 columns per inch, and the vertical density is 8 to 105 rows per inch.

5. The sound-absorbing fabric for triboelectrification of materials based on vibration according to any one of claims 1 to 3, characterized in that The raw materials for making the ground weave yarns and the vibration yarns are two or more materials selected from conductive fibers or dielectric fibers; the conductive fibers or dielectric fibers are at least one of single-component fibers, fibers with conductive properties obtained by surface processing, and core-shell composite fibers with a dielectric fiber or a conductive fiber in the cortex.

6. The sound-absorbing fabric based on triboelectrification by vibration according to claim 5, characterized in that, The dielectric fibers include at least one of polyoxymethylene fibers, polyamide fibers, melamine fibers, wool fibers, silk fibers, cotton fibers, hemp fibers, regenerated cellulose fibers, regenerated protein fibers, polyvinyl alcohol, polyimide fibers, polytetrafluoroethylene fibers, polyvinyl chloride fibers, chlorinated polyvinyl chloride fibers, polypropylene fibers, polyethylene fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, polyester fibers, polyurethane fibers, modacrylic fibers, and polyacrylonitrile fibers.

7. The sound-absorbing fabric for triboelectrification of materials based on vibration according to claim 5, characterized in that, The conductive fibers include at least one of metal conductive fibers, metal-coated fibers, conductive metal compound conductive fibers, metal complex fibers, carbon-based conductive fibers, and conductive polymer fibers.

8. The sound-absorbing fabric for triboelectrification of materials based on vibration according to any one of claims 1 to 3, characterized in that The sound-absorbing fabric further includes an air layer, where 0 < the thickness of the air layer ≤ 500 mm.

9. The sound-absorbing fabric based on triboelectrification by vibration according to any one of claims 1 to 3, characterized in that The sound-absorbing fabric does not include an air layer.

10. A method for preparing a sound-absorbing fabric that generates static electricity by material contact based on vibration according to any one of claims 1 to 9, characterized in that, The sound-absorbing fabric is at least one of a single-layer fabric, spacer fabric, double-layer fabric, and multi-layer fabric obtained by integral molding or step-by-step processing in a manner of weaving, knitting, non-woven, braiding, or sewing.

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