Double-layer structure air layer knitted fabric as well as preparation method and application thereof

Abstract

The invention discloses a double-layer structure air layer knitted fabric and a preparation method and application thereof.The double-layer structure air layer knitted fabric comprises a first fabric layer and a second fabric layer, the first fabric layer and the second fabric layer are both weft-knitted fabrics, the first fabric layer is located below the second fabric layer, and the second fabric layer is located below the first fabric layer. The first fabric layer is formed by knitting stretch yarns, the second fabric layer is formed by knitting inelastic yarns, the first fabric layer and the second fabric layer have the same needle number and are connected through turning needles which are arranged at intervals, and the second fabric layer forms wrinkles under the turning needle connection after the elastic force of the first fabric layer shrinks, each turning needle forms a turning needle hole in the first fabric layer, and the first fabric layer is provided with turning needle holes which are arranged along rows and are arranged at intervals. The sound absorption material prepared from the air layer knitted fabric with the double-layer structure is soft in texture, light and thin, and can absorb sound waves with specific frequency.

Description

Technical Field

[0001] The present invention belongs to the technical field of textiles, and particularly relates to a double-layered air layer knitted fabric, a preparation method thereof, and an application thereof. Background Art

[0002] Common sound absorption structures include multi-layer structures, gradient structures, sandwich structures, etc. Although these structures can also solve problems such as sound absorption and noise reduction, there are problems such as poor interfacial bonding, easy delamination, complex processes and high costs, and it is difficult to form a specific three-dimensional structure. At the same time, these structures are single and cannot be designed into special structures with special impedance matching effects, and it is difficult to make full use of them in a limited space range. Traditional sound absorption materials are difficult to have both the characteristics of lightness, softness and a high sound absorption coefficient. In order to match the long wavelength under low-frequency periodic signals, it is usually required that the structure size be large enough to ensure that the incident wavelength can be consumed within the structure without penetrating the structure, but this will also lead to problems such as large volume and heaviness of the sound absorption material, which limits its application in the field of flexible noise reduction. Summary of the Invention

[0003] Aiming at the deficiencies of existing traditional sound absorption materials, the purpose of the present invention is to provide a double-layered air layer knitted fabric. This double-layered air layer knitted fabric is made of weft knitting in one piece to form an air layer structure, and a undulating structure similar to a wedge is formed thereon. This double-layered air layer knitted fabric can be used as the sound absorption framework of a sound absorption material.

[0004] Another object of the present invention is to provide a preparation method of the double-layered air layer knitted fabric.

[0005] Another object of the present invention is to provide the use of the above double-layered air layer knitted fabric in sound absorption.

[0006] Another object of the present invention is to provide a sound absorption material which uses the double-layered air layer knitted fabric as the sound absorption framework.

[0007] The object of the present invention is achieved by the following technical solutions.

[0008] A double-layered air layer knitted fabric, comprising: a first fabric layer and a second fabric layer. Both the first fabric layer and the second fabric layer are weft knitted fabrics. The first fabric layer is located below the second fabric layer. The first fabric layer is knitted with elastic yarns, and the second fabric layer is knitted with inelastic yarns. The number of needles of the first fabric layer and the second fabric layer is the same and they are connected by spaced-overturning needles. After the first fabric layer elastically contracts, the second fabric layer forms folds under the connection of the overturning needles. Among them, each overturning needle forms an overturning needle hole on the first fabric layer, and the first fabric layer is formed with overturning needle holes arranged in rows and spaced apart.

[0009] In the above technical solution, the number of needles between adjacent purl holes in the same row is 3N + 1, where N is a positive integer greater than or equal to 1.

[0010] In the above technical solution, the purl holes in adjacent rows are arranged staggeredly, and the purl holes in adjacent rows are separated by 4N + 1 needle rows, where N is a positive integer greater than or equal to 1.

[0011] In the above technical solution, the purl holes in adjacent rows are arranged staggeredly: the purl holes in adjacent rows are offset to the left by m needles. When N is odd, m = (3N + 1) / 2; when N is even, m = (3N + 2) / 2.

[0012] In the above technical solution, in order to make the folds form a more obvious undulating effect, the elastic elongation rate of the elastic yarn is 30 - 50% (the elastic yarn has the ability to stretch and fully recover within the elastic elongation rate, and can be repeatedly stretched within the elastic elongation rate without generating permanent deformation).

[0013] The method for preparing the above double-layer structure air layer knitted fabric includes: knitting the first fabric layer by plain knitting on the first needle bed and knitting the second fabric layer by plain knitting on the second needle bed. The method for obtaining each purl is: turning the position on the first fabric layer knitted on the first needle bed where a purl hole needs to be formed to the second needle bed and turning left by one needle and intersecting with the position of the second needle bed where there is no elastic yarn, and forming a purl through this intersection.

[0014] The use of the above double-layer structure air layer knitted fabric in sound absorption.

[0015] A sound-absorbing material, comprising: the above double-layer structure air layer knitted fabric.

[0016] In the above technical solution, all or part of the pores surrounded by the inner coils in the double-layer structure air layer knitted fabric are filled with a pore filler.

[0017] In the above technical solution, the pore filler is a silica gel matrix.

[0018] The method for preparing the above sound-absorbing material includes: loading the pore filler into the pores surrounded by the inner coils in the double-layer structure air layer knitted fabric and drying to obtain the sound-absorbing material.

[0019] The double-layer structure air layer knitted fabric of the present invention integrally forms the first fabric layer and the second fabric layer through the connection of purls. Utilizing the elasticity of the elastic yarn, the surface of the second fabric layer is convex in a corrugated shape in the natural state, and the first fabric layer has a flat structure with evenly distributed purl holes. The sound-absorbing material prepared from this double-layer structure air layer knitted fabric is soft in texture and light in weight, can absorb sound waves of specific frequencies, and achieves excellent medium and high-frequency sound absorption effects under the conditions of light weight and small size, and has great application potential in the field of sound absorption. Description of the Drawings

[0020] Figure 1 is a structural schematic diagram of a double-layered air layer knitted fabric;

[0021] Figure 2 is a structural diagram of the first fabric layer;

[0022] Figure 3 are photos of (a) the second fabric layer and (b) the first fabric layer in the double-layered air layer knitted fabric;

[0023] Figure 4 is the layout drawing of the double-layered air layer knitted fabric in Example 1;

[0024] Figure 5 is the layout drawing of the double-layered air layer knitted fabric in Example 2;

[0025] Figure 6 is the layout drawing of the double-layered air layer knitted fabric in Example 3;

[0026] Figure 7 is the layout drawing of the fourth fabric layer in Comparative Example 1;

[0027] Figure 8 is the layout drawing of the third fabric layer in Comparative Example 1;

[0028] Figure 9 is the layout drawing of the fourth fabric layer in Comparative Example 1 (with artificial stitching points);

[0029] Figure 10 is the layout drawing of the fourth fabric layer in Comparative Example 2;

[0030] Figure 11 is the layout drawing of the fourth fabric layer in Comparative Example 2 (with artificial stitching points);

[0031] Figure 12 is the sound absorption coefficient of the sound absorption material.

[0032] Wherein, 1: the first fabric layer, 1-1: purl hole, 2: the second fabric layer, 2-1: fold. Detailed Embodiments

[0033] The following combines the accompanying drawings to elaborate in detail on the double-layered air layer knitted fabric of the present invention and its uses.

[0034] Examples 1 to 3

[0035] A double-layered air layer knitted fabric, as Figure 1As shown in the figure, it includes: a first fabric layer 1 and a second fabric layer 2. Both the first fabric layer 1 and the second fabric layer 2 are weft knitted fabrics. The first fabric layer 1 is located below the second fabric layer 2. The first fabric layer 1 is knitted with elastic yarn, and the second fabric layer 2 is knitted with inelastic yarn. The number of needles of the first fabric layer 1 and the second fabric layer 2 is the same and they are connected by purl stitches arranged at intervals. After the first fabric layer 1 elastically contracts, under the connection of the purl stitches, the second fabric layer 2 forms folds 2-1. Among them, each purl stitch forms a purl hole 1-1 on the first fabric layer 1, as Figure 2 shown, the first fabric layer 1 is formed with purl holes 1-1 arranged in rows and at intervals.

[0036] The number of needles between adjacent purl holes 1-1 in the same row is 3N + 1, and the number of needle rows between adjacent purl holes 1-1 in adjacent rows is 4N + 1, where N is shown in Table 1.

[0037] The purl holes 1-1 in adjacent rows are staggered. Specifically: the purl holes 1-1 in adjacent rows are staggered m needles to the left. When N is odd, m = (3N + 1) / 2; when N is even, m = (3N + 2) / 2. m is shown in Table 1.

[0038] The preparation method of the above double-layer structure air layer knitted fabric includes: weft plain knitting the first fabric layer 1 through the first needle bed (rear needle bed) and weft plain knitting the second fabric layer 2 through the second needle bed (front needle bed). The method for obtaining each purl stitch is: turning the first fabric layer 1 knitted on the first needle bed to the second needle bed at the position where the purl hole 1-1 needs to be formed, turning one needle to the left and intersecting with the inelastic yarn at this needle position on the second needle bed, and forming a purl stitch through this intersection.

[0039] Since the yarn on the first needle bed is elastic yarn and has elasticity, after knitting is completed, in the natural state, the first fabric layer 1 knitted by the first needle bed shrinks to a certain extent. Because the second fabric layer 2 knitted by the second needle bed is connected to the first fabric layer 1 through purl stitches, in the natural state, the second fabric layer 2 is affected by the shrinkage of the first fabric layer 1 and forms folds 2-1 bulges. Because the distribution of the purl holes 1-1 on the first fabric layer 1 is regular, the second fabric layer 2 forms a regular corrugated structure under the regular purl holes 1-1. The size of the corrugated structure of the second fabric layer 2 is closely related to the tension of the elastic yarn used in the first fabric layer 1. When the yarn used in the second fabric layer 2 remains unchanged, the greater the tension of the elastic yarn used in the first fabric layer 1, the greater the amplitude of the corrugated structure formed by the double-layer structure air layer knitted fabric.

[0040] For the weft plain knitting of the double-layer structure air layer knitted fabric in Examples 1 to 3, Figure 4 shown in the layout drawing is input into a double-needle bed computerized flat knitting machine (LXC-252SCV) to knit the double-layer structure air layer knitted fabric of Example 1. Figure 5The shown layout drawing is input into a double needle bed computerized flat knitting machine (LXC-252SCV) to knit the double-layered air layer knitted fabric of Example 2. Figure 6 The shown layout drawing is input into a double needle bed computerized flat knitting machine (LXC-252SCV) to knit the double-layered air layer knitted fabric of Example 3, wherein the "color code No. 41" in the layout drawing corresponds to the purl connection.

[0041] In Examples 1 to 3, the elastic yarns of the double-layered air layer knitted fabrics are spandex-polyamide elastic yarns of 2040D (Weifang Yubang Textile Co., Ltd., with an elastic elongation rate of 35%). The non-elastic yarn of the double-layered air layer knitted fabric in Example 1 is 30s / 2 polyester yarn (Weifang Yubang Textile Co., Ltd.). The non-elastic yarn of the double-layered air layer knitted fabric in Example 2 is 30s / 2 cotton yarn (Weifang Yubang Textile Co., Ltd.). The non-elastic yarn of the double-layered air layer knitted fabric in Example 3 is 30s / 2 cotton hollow yarn (Weifang Yubang Textile Co., Ltd.). Figure 3 Shown are the photos of the first fabric layer 1 and the second fabric layer 2 of the double-layered air layer knitted fabric prepared in Example 1.

[0042] Table 1

[0043] Example N m Example 1 1 2 Example 2 2 4 Example 3 3 5

[0044] Comparative Example 1

[0045] A double-layered air layer knitted fabric includes: a third fabric layer and a fourth fabric layer. Both the third fabric layer and the fourth fabric layer are weft knitted fabrics (the third fabric layer is a plain weft knitting structure, and the fourth fabric layer is a purl stitch structure). The third fabric layer is located below the fourth fabric layer. The third fabric layer is knitted with 30s / 2 cotton yarn, and the fourth fabric layer is knitted with 30s / 2 cotton yarn. The number of needles of the third fabric layer and the fourth fabric layer is the same and they are connected by connecting points arranged at intervals. Among them, artificial yarn (30s / 2 cotton yarn) passes through the "artificial stitching points" opposite to each other in the third fabric layer and the fourth fabric layer and is sewn to form connecting points. The connecting points are arranged in rows in the third fabric layer. The number of needles spaced between adjacent connecting points in the same row in the third fabric layer is 7. The connecting points in adjacent rows are staggered. The third fabric layer corresponding to the connecting points in adjacent rows is spaced 5 needle rows apart. The connecting points in adjacent rows are staggered 4 needles to the left.

[0046] The preparation method of the double-layered air layer knitted fabric in Comparative Example 1 includes: Figure 8 The shown layout drawing is input into a double needle bed computerized flat knitting machine (LXC-252SCV) to knit the third fabric layer through the needle bed, Figure 7The shown layout drawing is input into the double needle bed computerized flat knitting machine (LXC-252SCV) to knit the fourth fabric layer. Manually use yarn (cotton yarn of 30s / 2) to pass through the "manual stitching points" opposite to the third fabric layer and the fourth fabric layer and sew to form connection points.

[0047] The plain stitch and purl stitch form a double-layered structure air layer knitted fabric. Since the purl stitch has a wavy effect, the manual sewing can be carried out according to the position of the purl stitch. When manually sewing, it is necessary to avoid damaging the wavy effect of the purl stitch. The position of the connection points is further clarified through the layout drawing of the fourth fabric layer. The connection points are as Figure 9 shown by the "manual stitching points" in

[0048] Comparative Example 2

[0049] A double-layered structure air layer knitted fabric is basically the same as the double-layered structure air layer knitted fabric in Comparative Example 1. The only difference lies in the position of the fourth fabric layer and the connection points. In this Comparative Example 2, the fourth fabric layer is obtained by inputting the shown layout drawing into the double needle bed computerized flat knitting machine (LXC-252SCV) and knitting through the needle bed. The position of the connection points is further clarified through the layout drawing of the fourth fabric layer. The connection points are as Figure 10 shown by the "manual stitching points" in Figure 11

[0050] Example 4

[0051] A method for preparing a sound-absorbing material includes: using a brush to coat a two-component adhesive (pore filler, silica gel matrix) on the surface of the double-layered structure air layer knitted fabric so that both the top surface and the bottom surface of the double-layered structure air layer knitted fabric are penetrated with the two-component adhesive (the surface of the double-layered structure air layer knitted fabric is slightly moist after coating). Due to the pores in the fabric, the two-component adhesive will naturally penetrate into the double-layered structure air layer knitted fabric under the action of gravity. The vulcanization condensation reaction of the two-component adhesive occurs simultaneously on the upper surface and the internal pores of the fabric, and it is dried and formed at room temperature to obtain the sound-absorbing material. Among them, the double-layered structure air layer knitted fabric is one of those in Examples 1 to 3 and Comparative Examples 1 to 2.

[0052] The two-component adhesive is an addition-curing room temperature vulcanizing liquid silica gel with a degree of 5° after molding (purchased from Dongguan Xubai New Material Technology Co., Ltd.). The A glue and the B glue are mixed in a mass ratio of 10:1, and uniformly mixed at a speed of 1200 rpm for 5 minutes before use. The A glue and the B glue are shown in Table 2.

[0053] Table 2

[0054]

[0055]

[0056] ​To characterize the sound absorption performance of the sound-absorbing material, according to the GB / T 18696.2-2002 standard, an impedance tube test system was used to test the sound absorption coefficient of the sound-absorbing material. The test results are shown in Table 3 and Figure 12 as follows. From Table 3 and Figure 12 it can be seen that the sound-absorbing materials prepared in Examples 1-3 of the present invention have a relatively wide absorption frequency band. In the low and medium frequency range of 1500-3000 Hz, the average sound absorption coefficient is greater than 0.4, and the maximum sound absorption coefficient can reach 0.95.

[0057] Table 3

[0058] Frequency (Hz) 1500 1750 2000 2250 2500 2750 3000 Average Highest Example 1 0.33 0.37 0.51 0.64 0.88 0.98 0.96 0.67 0.98 Example 2 0.41 0.50 0.73 0.89 0.95 0.87 0.71 0.72 0.95 Example 3 0.72 0.87 0.89 0.79 0.64 0.55 0.45 0.70 0.89 Comparative Example 1 0.04 0.06 0.09 0.20 0.25 0.41 0.59 0.18 0.59 Comparative Example 2 0.08 0.12 0.20 0.31 0.48 0.69 0.89 0.40 0.89

[0059] The thickness of the sound-absorbing material obtained from the double-layer structure air layer knitted fabric prepared in Example 1 is 4 mm, the thickness of the sound-absorbing material obtained from the double-layer structure air layer knitted fabric prepared in Example 2 is 7 mm, and the thickness of the sound-absorbing material obtained from the double-layer structure air layer knitted fabric prepared in Example 3 is 10 mm.

[0060] Since the double-layer structure air layer knitted fabric is formed by the interlacing of coils, and the pores formed between the coils are relatively large, on the basis of the double-layer structure air layer knitted fabric, a pore filler is used to adjust the pores formed between the coils, and at the same time, the stability of the sound-absorbing material can be improved (the pore filler can penetrate into the pores formed between the coils in the double-layer structure air layer knitted fabric, but cannot completely penetrate into the internal pores of the yarn, which does not affect the microscopic pores that consume sound energy).

[0061] The folds formed by the second fabric layer of the double-layer structure air layer knitted fabric are similar to wedges. The special shape of the wedges makes the double-layer structure air layer knitted fabric have a gradually changing cross-sectional area. The acoustic impedance gradually changes with the change of the wedge area. The change of the acoustic impedance enables the double-layer structure air layer knitted fabric to better match the acoustic impedance of the air, allowing more sound energy to enter its interior. There are many tiny pores (i.e., internal pores of the yarn) that penetrate each other and are connected to the surface inside the yarn of the wedge, which conforms to the characteristics of porous materials. When sound waves enter the interior of the double-layer structure air layer knitted fabric, due to the viscous effect of the internal pores of the yarn, the air molecules vibrate and rub against the pore walls of the internal pores of the yarn, converting the sound energy into heat dissipation and consuming a large amount of sound energy, achieving a good sound absorption effect.

[0062] The double-layer structure air layer knitted fabric of the present invention is integrally formed by knitting, giving full play to the advantages of the knitting structure, combining with a functional matrix to form a composite material. The structure design is simple, the knitting and forming are convenient. Using the impedance matching mechanism of the undulating structure, the absorption of high-frequency sound waves is improved. The multi-porous structure can improve the absorption performance of low-frequency sound waves, thereby improving the sound absorption effect in the low and medium frequencies. The functional matrix helps to realize the application of sound absorption and other required performances in different scenarios.

[0063] The above has made an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification or equivalent replacement that can be made by those skilled in the art without creative labor falls within the protection scope of the present invention.

Claims

1. A double-layer air layer knitted fabric, characterized in that: include: A first fabric layer and a second fabric layer, wherein the first fabric layer and the second fabric layer are both weft knitted fabrics, the first fabric layer is located below the second fabric layer, the first fabric layer is knitted with elastic silk, and the second fabric layer is knitted with inelastic yarn, the first fabric layer and the second fabric layer have the same number of needles and are connected by turn-over stitches arranged at intervals, and the second fabric layer is wrinkled under the turn-over stitch connection after the elastic contraction of the first fabric layer, wherein each turn-over stitch forms a turn-over stitch hole on the first fabric layer, and the first fabric layer is formed with turn-over stitch holes arranged in rows and arranged at intervals.

2. The double-layer structure air layer knitted fabric according to claim 1, characterized in that: The number of stitches between adjacent turning needle holes in the same row is 3N+1, where N is a positive integer greater than or equal to 1.

3. The double-layer structure air layer knitted fabric according to claim 1 or 2, characterized in that: The needle holes in adjacent rows are arranged alternately, and the interval between the needle holes in adjacent rows is 4N+1 needle rows, where N is a positive integer greater than or equal to 1.

4. The double-layer structure air layer knitted fabric according to claim 3, characterized in that: The needle holes in adjacent rows are staggered: the needle holes in adjacent rows are staggered m needles to the left. When N is an odd number, m=(3N+1) / 2; when N is an even number, m=(3N+2) / 2.

5. The double-layer structure air layer knitted fabric according to claim 4, characterized in that: The elastic elongation of the elastic yarn is 30-50%.

6. The method for preparing the double-layer structure air layer knitted fabric according to claim 1, characterized in that: include: The first fabric layer is knitted by the first needle bed with plain needles and the second fabric layer is knitted by the second needle bed with plain needles, and the method for obtaining each turn-over stitch is as follows: the first fabric layer woven by the first needle bed is turned toward the second needle bed at the position where a turn-over needle hole is required and turned one needle to the left and intersect with the inelastic yarn at the needle position of the second needle bed, and a turn-over stitch is formed through the intersection.

7. Use of the double-layer air layer knitted fabric as claimed in claim 1 in sound absorption.

8. A sound absorbing material, characterized in that: It comprises the double-layer structure air layer knitted fabric as claimed in claim 1.

9. The sound absorbing material according to claim 8, characterized in that: All or part of the pores surrounded by the inner coils of the double-layer structure air layer knitted fabric are filled with pore fillers.

10. A method for preparing the sound absorbing material according to claim 8 or 9, characterized in that: include: The pore filler is loaded in the pores formed between the inner coils of the double-layer structure air layer knitted fabric, and dried to obtain the sound absorbing material.

Images