double weave

Abstract

This application relates to a double woven fabric. According to this application, when stress is applied to a tether formed inside an airbag base fabric during airbag deployment, the stress can be dispersed by breaking a low-strength yarn inside the airbag base fabric instead of the tether yarn, thereby preventing breakage of the tether yarn and providing a double woven fabric that can control the deployed shape of the airbag.

Description

[Technical Field]

[0001] This application relates to a dual-layer fabric. Specifically, this application relates to a dual-layer fabric that can be used as an airbag. [Background technology]

[0002] In the event of an accident while a vehicle is moving, an airbag is installed to protect the occupant. For example, a curtain-type airbag can be installed in a position such as the side frame of a vehicle. Curtain-type airbags must have excellent internal pressure retention in case the vehicle rolls over, so they can be woven using a seamless jacquard weave. Airbag fabrics manufactured in this manner are generally called OPW (One-piece woven).

[0003] OPW uses a weaving method in which pockets are formed immediately during the seamless weaving process, which makes it difficult to control inflation. Excessive inflation can cause brain injury to the user. For this reason, conventional technology has formed tethers inside the airbag fabric to appropriately control the inflation speed and volume of the cushion. However, when the airbag inflates, stress is applied to the tether, which easily breaks the yarn that forms the tether, preventing the full effect of the tether. Summary of the Invention [Problem to be solved by the invention]

[0004] One object of the present application is to provide a double-layered fabric that overcomes the above-mentioned problems of the prior art.

[0005] Another object of the present application is to provide an airbag that protects the occupant from brain injury.

[0006] The above and other objects of the present application can all be achieved by the invention of the present application, which is described in detail below. [Means for solving the problem]

[0007] According to one embodiment of the present application, there is provided a double woven fabric comprising: a first fabric layer in which a first yarn extending in a first direction and a second yarn extending in a second direction are woven crosswise; a second fabric layer in which a third yarn extending in the first direction and a fourth yarn extending in the second direction are woven crosswise; and a tether yarn woven with the first yarn and the third yarn to connect the first fabric layer and the second fabric layer to each other, wherein at least a portion of the first yarn and the third yarn comprise low-strength yarns and high-strength yarns arranged alternately in the second direction, and wherein the tether yarn is woven such that in the region where the tether yarn that crossed the first yarn crosses the third yarn, the tether yarn is hooked only on the low-strength yarn of the first yarns and the low-strength yarn of the third yarns.

[0008] The tether yarn is woven with the first yarn of the first fabric layer and the third yarn of the second fabric layer, and is woven so that the tether yarn that crosses the first yarn is hooked only to the low-strength yarn of the first yarn and the low-strength yarn of the third yarn in the region where the tether yarn crosses the third yarn, so that when the double fabric expands, the low-strength yarn can be ruptured by the force applied to the tether yarn.

[0009] The tether thread may be one or more than two. In one example, when the tether thread is two or more, the two or more tether threads may cross each other between the first and second fabric layers to form an X-shape when observed in any cross section of the double woven fabric.

[0010] In one example, the first yarns are made up of low-strength yarns and high-strength yarns arranged alternately in the second direction, and the first yarns can cross the second yarns in pairs of one low-strength yarn and one high-strength yarn.

[0011] In one example, the third yarn is made up of low-strength yarns and high-strength yarns arranged alternately in the second direction, and the third yarn can cross the fourth yarn in pairs of one low-strength yarn and one high-strength yarn.

[0012] In one example, the first threads are composed of low-strength threads and high-strength threads arranged alternately in the second direction, and some of the first threads can cross the tether threads in pairs, one low-strength thread and one high-strength thread.

[0013] In one example, the third yarn is composed of low-strength yarns and high-strength yarns arranged alternately in the second direction, and a portion of the third yarns can cross the tether yarn in pairs, one low-strength yarn and one high-strength yarn.

[0014] In a more specific example, the first and third yarns are composed of low-strength yarns and high-strength yarns arranged alternately in the second direction, and the first and third yarns may each cross the second and fourth yarns in pairs of one low-strength yarn and one high-strength yarn. At least a portion of the first yarns may cross the tether yarn in pairs of one low-strength yarn and one high-strength yarn, and at least a portion of the third yarns may cross the tether yarn in pairs of one low-strength yarn and one high-strength yarn. In a region where the tether yarn that crossed the first yarn crosses the third yarn, the tether yarn may be woven so that it is hooked only on the low-strength yarn of the first yarns and the low-strength yarn of the third yarns.

[0015] In an example in which the first yarn and the third yarn are each composed of low-strength yarns and high-strength yarns arranged alternately in the second direction, if the number of high-strength yarns is n, the number of low-strength yarns may be n+1.

[0016] In another example, the first yarn may include low-strength yarns and high-strength yarns alternately arranged in the second direction in some regions, and high-strength yarns in the remaining regions. In the some regions, the first yarn may cross the second yarn in pairs of one low-strength yarn and one high-strength yarn, and in the remaining regions, the high-strength yarn may cross the second yarn.

[0017] In another example, the third yarn may include low-strength yarns and high-strength yarns alternately arranged in the second direction in some regions, and high-strength yarns in the remaining regions. In the some regions, the third yarn may cross the fourth yarn in pairs of one low-strength yarn and one high-strength yarn, and in the remaining regions, the high-strength yarn may cross the fourth yarn.

[0018] In another example, the first yarn may include low-strength yarns and high-strength yarns arranged alternately in the second direction in some regions and high-strength yarns in the remaining regions, where the first yarns, which are high-strength yarns, may cross the tether yarns.

[0019] In another example, the third yarn may include low-strength yarns and high-strength yarns arranged alternately in the second direction in some regions, and high-strength yarns in the remaining regions, where the third yarns, which are high-strength yarns, may intersect with the tether yarns.

[0020] In another more specific example, the first and third yarns may include low-strength yarns and high-strength yarns alternately arranged in the second direction in some regions, and high-strength yarns in the remaining regions. In the some regions, the first and third yarns may each form a pair of one low-strength yarn and one high-strength yarn, crossing the second and fourth yarns, respectively, and in the remaining regions, the first and third yarns, which are high-strength yarns, may cross the second and fourth yarns, respectively. In the remaining regions, the first yarn, which is a high-strength yarn, may cross the tether yarn, and the third yarn, which is a high-strength yarn, may cross the tether yarn. In the region where the tether yarn that crossed the first yarn crosses the third yarn, the tether yarn may be woven so that it is hooked only on the low-strength yarn of the first yarns and the low-strength yarn of the third yarns.

[0021] The first to fourth yarns and the tether yarn may each independently include one or more fibers selected from polyester fiber, polyamide fiber, polyaramid fiber, polyketone fiber, carbon fiber, and cellulose fiber, but are not limited thereto.

[0022] The low-strength yarns may, for example, have a lower fineness or a lower tenacity (N) than the high-strength yarns.

[0023] The high-strength yarn, the second yarn, and the fourth yarn can, for example, comprise the same fiber. [Effects of the Invention]

[0024] According to the present application, when stress is applied to the tether formed inside the airbag fabric during deployment, the stress can be dispersed by breaking the low-strength yarn inside the airbag fabric instead of the tether yarn, thereby preventing breakage of the tether yarn and providing a double woven fabric that can control the deployed shape of the airbag. As a result, the use of the double woven fabric can provide an airbag that protects against brain injury, etc. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a schematic diagram showing a cross section of a double woven fabric to which a tether has been applied according to the prior art; [Figure 2] 2 is a diagram illustrating the problem that stress is applied to the tether when the double woven fabric of FIG. 1 is deployed, making the tether thread T that constitutes the tether more likely to break. [Figure 3] FIG. 1 is a schematic diagram showing a cross section of a double woven fabric including a first fabric layer L1 in which a first yarn Y1 consisting of alternating low-strength yarn Y1a and high-strength yarn Y1b is woven with a second yarn Y2, and a second fabric layer L2 in which a third yarn Y3 consisting of alternating low-strength yarn Y3a and high-strength yarn Y3b is woven with a fourth yarn Y4, according to one embodiment. [Figure 4] 4 is a diagram illustrating that stress applied to the tether is dispersed to the low-strength yarns Y1a and Y3a when the double woven fabric of FIG. 3 is deployed. FIG. [Figure 5]This figure shows that even if stress is applied to the low-strength yarns Y1a and Y3a as shown in Figure 4, causing the low-strength yarns Y1a and Y3a to break, the tether yarn T will not break and will remain fastened to the first yarn Y1 and the third yarn Y3, thereby still being able to interconnect the first and second fabric layers L1 and L2. [Figure 6] FIG. 10 is a schematic diagram showing a cross section of a double woven fabric according to another embodiment, comprising a first fabric layer L1 in which a first yarn Y1 including alternating low-strength yarn Y1a and high-strength yarn Y1b in some regions AT and high-strength yarn Y1b in the remaining regions is woven with a second yarn Y2, and a second fabric layer L2 in which a third yarn Y3 including alternating low-strength yarn Y3a and high-strength yarn Y3b in some regions AT and high-strength yarn Y3b in the remaining regions is woven with a fourth yarn Y4. DETAILED DESCRIPTION OF THE INVENTION

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can easily understand and practice the present invention. However, as the present invention may be embodied in many different forms, it is not limited to the embodiments set forth herein.

[0027] According to one embodiment of the present application, there is provided a double woven fabric comprising: a first fabric layer in which a first yarn extending in a first direction and a second yarn extending in a second direction are woven crosswise; a second fabric layer in which a third yarn extending in the first direction and a fourth yarn extending in the second direction are woven crosswise; and a tether yarn woven with the first yarn and the third yarn to connect the first fabric layer and the second fabric layer to each other, at least a portion of the first yarn and the third yarn comprising low-strength yarns and high-strength yarns arranged alternately in the second direction, and the tether yarns are woven such that in a region where the tether yarn that crossed the first yarn crosses the third yarn, the tether yarn is hooked only to the low-strength yarn of the first yarns and the low-strength yarn of the third yarns.

[0028] In the prior art, double-layered fabrics for airbags with inner tethers have been manufactured without distinguishing between warp and weft yarns. For example, in the prior art, single yarns such as ordinary filament yarns or twisted yarns have been commonly used for the weft and warp yarns of double-layered fabrics. Such single yarns typically have a fineness of 400 to 600 denier.

[0029] 1 and 2, in this prior art, when the double woven fabric is inflated, the tether thread T constituting the tether suffers a problem of being cut by a direct force (expansion force). Furthermore, when force is applied to the tether thread T, the tether thread T and other threads Y1, Y2, Y3, and Y4 are pushed out of their original positions, causing pinholes. This problem reduces the degree to which the airbag retains its internal pressure.

[0030] This application was developed to solve these problems. Specifically, in this application, a pair of two types of yarns with different strengths is used as the weft or warp of a double-layered fabric, and a tether yarn is arranged by being hooked around the relatively low-strength yarn. With this configuration, when the double-layered fabric expands and an external force (tension or expansion force) acts on the tether yarn, only the low-strength yarn breaks, allowing the tether yarn to absorb the impact. As a result, this configuration prevents breakage of the tether yarn and air leakage due to pinholes. Furthermore, even if a low-strength yarn breaks, the tether yarn can be hooked onto the high-strength yarn located adjacent to it, allowing the expansion speed and / or expansion volume of the double-layered fabric to be controlled while maintaining the intended length of the tether composed of the tether yarn, as designed by the internal tether.

[0031] 3, the double-layered fabric includes a first fabric layer L1 and a second fabric layer L2. The first fabric layer L1 and the second fabric layer L2 may be disposed to face each other. The first fabric layer L1 and the second fabric layer L2 are connected to each other by a tether yarn (T).

[0032] The first fabric layer L1 may be woven with a first yarn (Y1) extending in a first direction (x direction) and a second yarn Y2 extending in a second direction (y direction) crossing each other. The second fabric layer L2 may be woven with a third yarn Y3 extending in the first direction (x direction) and a fourth yarn Y4 extending in the second direction (y direction) crossing each other. Here, the first yarn Y1 and the third yarn Y3 may be either a warp yarn or a weft yarn, and the second yarn Y2 and the fourth yarn Y4 may be the other of the warp yarn and the weft yarn.

[0033] The double-layered fabric has gas inflatability or expandability. For example, the double-layered fabric of the present application can have gas inflatability due to the bonding between the opposing first and second fabric layers L1 and L2. The double-layered fabric can also have a degree of airtightness that allows it to have the above-mentioned gas inflatability or expandability. For example, the first and second fabric layers L1 and L2 can be bonded together to prevent gas from escaping between them, and the double-layered fabric can be configured to withstand the pressure of expanding gas. As a result, the double-layered fabric expands when gas flows in, protecting the user from external impact.

[0034] The joining method between the first and second fabric layers L1, L2 is not particularly limited. For example, the first and second fabric layers L1, L2 may be produced by a one-piece weaving method, where the separate first and second fabric layers L1, L2 are woven simultaneously. In other words, the first and second fabric layers L1, L2 may be joined via a co-knit point.

[0035] In some double-layered fabrics for airbags, a seam is formed in the inflatable portion to control the deployed shape of the double-layered fabric upon inflation. However, according to one embodiment of the present application, a double-layered fabric that can inflate in a wind-line shape without stitching can be provided using a Jacquard loom. Specifically, the double-layered fabric according to the embodiment has a weaving pattern including an inner tether, so that a non-woven airbag can be provided in which a seam to control the deployed shape of the double-layered fabric upon inflation is not formed.

[0036] The position where the tether made of the tether yarn is applied to the double-layered fabric is not particularly limited. For example, the tether can be applied to a region of the double-layered fabric that receives the most force (stress) when the double-layered fabric actually expands.

[0037] 3, the tether yarn T, like the second yarn Y2 and the fourth yarn Y4, is interwoven with the first yarn Y1 and the third yarn Y3 by crossing them. In the drawings of the present application, for convenience of explanation, the tether yarn T is distinguished from the second yarn Y2 and the fourth yarn Y4, but since the tether yarn T is interwoven with the first yarn Y1 and the third yarn Y3 by crossing them, it can also be understood as one of the second yarn Y2 and the fourth yarn Y4. For example, when the second yarn Y2 and the fourth yarn Y4 are warp yarns, the tether yarn T can also be a warp yarn, and when the second yarn Y2 and the fourth yarn Y4 are weft yarns, the tether yarn T can also be a weft yarn.

[0038] 3, in one example, the first yarns Y1 may be composed of low-strength yarns Y1a and high-strength yarns Y1b arranged alternately in the second direction (y direction). The first yarns Y1 may be a pair of one low-strength yarn Y1a and one high-strength yarn Y1b, and may cross the second yarns Y2 to form the first fabric layer L1.

[0039] In one example, the third yarns Y3 may be composed of low-strength yarns Y3a and high-strength yarns Y3b arranged alternately in the second direction (y direction). The third yarns Y3 may be a pair of one low-strength yarn Y3a and one high-strength yarn Y3b, and may cross the fourth yarns Y4 to form the second fabric layer L2.

[0040] The low-strength yarns Y1a, Y3a and the high-strength yarns Y1b, Y3b that make up the first yarn Y1 or the third yarn Y3 are arranged adjacent to each other and alternately, and no other fibers may be present between the low-strength yarns Y1a, Y3a and the high-strength yarns Y1b, Y3b.

[0041] In this specification, a yarn having a relatively high strength compared to two types of fibers having different strengths is referred to as a “high-strength yarn,” and a yarn having a relatively low strength is referred to as a “low-strength yarn.” In one example, low-strength yarns Y1a and Y3a refer to yarns having a smaller fineness or lower tenacity (N) than high-strength yarns Y1b and Y3b.

[0042] In one example, when the first yarn Y1 and the third yarn Y3 are composed of low-strength yarns Y1a, Y3a and high-strength yarns Y1b, Y3b, respectively, arranged alternately in the second direction (y direction), when the number of high-strength yarns Y1b, Y3b is n, the number of low-strength yarns Y1a, Y3a may be n+1 or greater.

[0043] Referring to FIG. 3, in one example, the first yarn Y1 may be woven with the tether yarn T in a pair consisting of one low-strength yarn Y1a and one high-strength yarn Y1b.

[0044] In one example, the third yarn Y3 may be woven in such a way that one low-strength yarn Y3a and one high-strength yarn Y3b form a pair and cross the tether yarn T.

[0045] Referring to Figure 3, in one example, in the region AT where the tether yarn T that intersects with the first yarn Y1 intersects with the third yarn Y3, the tether yarn T may be woven so that it is hooked only on the low-strength yarn Y1a of the first yarn Y1 and the low-strength yarn Y3a of the third yarn Y3.

[0046] Referring to FIG. 4, when the double woven fabric includes the tether thread T woven as described above, the force applied to the tether thread T (expansion force due to gas or tension applied to the tether thread T due to expansion due to gas) when the double woven fabric expands may cause the low-strength threads Y1a and Y3a hooked to the tether thread T to burst (break).

[0047] 5, the double-layered fabric according to one embodiment can maintain the intended shape of the tether by absorbing stress applied to the tether when the double-layered fabric is deployed by the rupture of the low-strength yarns Y1a and Y3a. Therefore, the use of the double-layered fabric according to one embodiment has the advantage of making it easy to control the deployed shape of the airbag and effectively preventing brain damage to the user due to excessive inflation of the airbag.

[0048] 6, in one example, the first yarn Y1 may include low-strength yarns Y1a and high-strength yarns Y1b arranged alternately in the second direction (y direction) in a portion of the region AT, and may include high-strength yarns Y1b in the remaining region. In the portion of the region AT, the first yarn Y1 may cross the second yarn Y2 in pairs of one low-strength yarn Y1a and one high-strength yarn Y1b, and in the remaining region, the high-strength yarn Y1b may cross the second yarn Y2 to form the first fabric layer L1.

[0049] In one example, the third yarn Y3 may include low-strength yarns Y3a and high-strength yarns Y3b arranged alternately in the second direction (y direction) in a portion of the region AT, and may include high-strength yarns Y3b in the remaining region. In the portion of the region AT, the third yarn Y3 intersects with the fourth yarn Y4 in pairs of one low-strength yarn Y3a and one high-strength yarn Y3b, and in the remaining region, the high-strength yarn Y3b intersects with the fourth yarn Y4 to form the second fabric layer L2.

[0050] The arrangement of the low-strength yarns Y1a, Y3a and the high-strength yarns Y1b, Y3b in the partial region AT may be the same as that described with reference to FIG.

[0051] Referring to FIG. 6, in one example, the high-strength yarn Y1b, which is the first yarn Y1 in the remaining region excluding the partial region AT, may be interwoven with the tether yarn T by crossing it.

[0052] In one example, the high-strength yarn Y3b, which is the third yarn Y3 in the remaining region excluding the partial region AT, may be interwoven with the tether yarn T by crossing it.

[0053] 6, in one example, the tether yarn T that crosses the first yarn Y1 may be woven so that it is hooked only to the low-strength yarn Y1a of the first yarn Y1 and the low-strength yarn Y3a of the third yarn Y3 in the region AT where the tether yarn T crosses the first yarn Y1 and the third yarn Y3. By interweaving the tether yarn T in this manner, the same effect as described above can be achieved. When the low-strength yarns Y1a and Y3a are arranged only in a portion of the region AT as in FIG. 6, a double woven fabric with higher strength can be provided.

[0054] The double woven fabric may include two or more tether threads T. For convenience, Fig. 3 and Fig. 6 show cross sections of a double woven fabric to which two tether threads T are applied, but the number of tether threads T is not limited to this.

[0055] Referring to FIG. 3 or 6, the two or more tether threads T1 and T2 may be formed, for example, in an X-shape by crossing each other between the first and second fabric layers L1 and L2 when viewed from any one cross section of the double-layered fabric.

[0056] Specifically, the first yarn Y1 and the third yarn Y3 may be arranged in the second direction (y direction) from one end (e.g., the left side in FIG. 3 or 6) to the other end (e.g., the right side in FIG. 3 or 6). The first fabric layer L1 and the second fabric layer L2 are formed by interweaving the first yarn Y1 and the third yarn Y3 with the second yarn Y2 and the fourth yarn Y4, respectively.

[0057] 3 or 6, a first tether yarn T1, which is one of the multiple tether yarns T, may be woven with a first yarn Y1 in a direction from one end to the other end in the second direction (y direction) to form a part of a first fabric layer L1. Such a first tether yarn T1 may be woven with a third yarn Y3 in a state in which it is hooked only to a low-strength yarn Y1a of the first yarn Y1. Here, the first tether yarn T1 may be woven with a third yarn Y3 in a direction from one end to the other end in the second direction (y direction) to form a part of a second fabric layer L2. The first tether yarn T1 may be woven with a third yarn Y3 in a state in which it is hooked only to a low-strength yarn Y1a of the first yarn Y1, passing through a space between the first fabric layer L1 and the second fabric layer L2, and being hooked only to a low-strength yarn Y3a of the third yarn Y3 of the second fabric layer L2. This allows the force (stress) applied to the first tether thread T1 to be dispersed to the low-strength threads Y1a, Y3a of the first and second fabric layers L1, L2, as described above, thereby preventing the tether from bursting.

[0058] 3 or 6, the second tether yarn T2, which is another of the multiple tether yarns T, may be woven with the third yarn Y3 in a direction from one end to the other end in the second direction (y direction) to form a part of the second fabric layer L2. Such a second tether yarn T2 may be woven with the first yarn Y1 in a state in which it is hooked only on the low-strength yarn Y3a of the third yarn Y3. In this case, the second tether yarn T2 may be woven with the first yarn Y1 in a direction from one end to the other end in the second direction (y direction) to form a part of the first fabric layer L1. Like the first tether yarn T1, the second tether yarn T2 may be woven with the first fabric layer L1 and the second fabric layer L2 in a state in which it is hooked only on the low-strength yarn Y3a of the third yarn Y3, and may pass through the space between the first fabric layer L1 and the second fabric layer L2 and be hooked only on the low-strength yarn Y1a of the first yarn Y1 of the first fabric layer L1. 3 and 6, the first and second tether threads T1 and T2 can cross each other between the first and second fabric layers L1 and L2 to form an X-shape when viewed from the cross section of the double-layered fabric. When multiple tether threads T1 and T2 are crossed each other, a tether can be formed that more firmly connects the first and second fabric layers L1 and L2.

[0059] The type of yarn used to weave the double woven fabric is not particularly limited. For example, the first to fourth yarns Y1, Y2, Y3, Y4 and the tether yarn T may each independently comprise one or more fibers selected from polyester fibers (e.g., PET), polyamide fibers (e.g., nylon), polyaramid fibers, polyketone fibers, carbon fibers, and cellulose fibers.

[0060] In one example, the low-strength yarns Y1a and Y3a may be fibers having a fineness in the range of 10 to 400 denier. Specifically, the low-strength yarns Y1a and Y3a may refer to fibers having a fineness of, for example, 50 denier or more, 150 denier or more, 200 denier or more, 250 denier or more, 300 denier or more, or 350 denier or more, and an upper limit of 350 denier or less, 300 denier or less, 250 denier or less, 200 denier or less, 150 denier or less, 100 denier or less, or 50 denier or less.

[0061] In one example, the high-strength yarns Y1b, Y3b may refer to fibers having a relatively larger fineness than the low-strength yarns Y1a, Y3a. Specifically, the difference in fineness between the high-strength yarns Y1b, Y3b and the low-strength yarns Y1a, Y3a may be, for example, at least 50 denier or more, 100 denier or more, 150 denier or more, 200 denier or more, 250 denier or more, 300 denier or more, 350 denier or more, 400 denier or more, 450 denier or more, 500 denier or more, 550 denier or more, or 600 denier or more. The upper limit of the difference in fineness between the high-strength yarns Y1b, Y3b and the low-strength yarns Y1a, Y3a may be, for example, 900 denier or less, 800 denier or less, 700 denier or less, 600 denier or less, 500 denier or less, 400 denier or less, 300 denier or less, 200 denier or less, or 100 denier or less.

[0062] In one example, the low-tenacity yarns Y1a and Y3a may refer to fibers having a relatively lower tenacity than the high-tenacity yarns Y1b and Y3b. Specifically, the low-tenacity yarns Y1a and Y3a may have a tenacity of 50% or less of the tenacity of the high-tenacity yarns Y1b and Y3b. For example, if the high-tenacity yarns Y1b and Y3b have a tenacity of 30 to 50 N, the low-tenacity yarns Y1a and Y3a may have a tenacity of about 50% or less of the high-tenacity yarns Y1b and Y3b. For example, the low-tenacity yarns Y1a and Y3a may have a tenacity of about 25 N or less, 20 N or less, or 15 N or less.

[0063] In one example, the high-strength yarns Y1b and Y3b, the second yarn Y2, and the fourth yarn Y4 may be the same fiber or may contain the same fiber. For example, the high-strength yarns Y1b and Y3b, the second yarn Y2, and the fourth yarn Y4 may have the same strength. In another example, the high-strength yarns Y1b and Y3b, the second yarn Y2, and the fourth yarn Y4, and the tether yarn T may be the same fiber or may contain the same fiber. For example, the high-strength yarns Y1b and Y3b, the second yarn Y2, the fourth yarn Y4, and the tether yarn T may have the same strength. In other words, the double woven fabric according to one embodiment may be woven using high-strength yarns and low-strength yarns as the first to fourth yarns and the tether yarn. [Explanation of symbols]

[0064] L1: 1st textile layer, L2: 2nd textile layer Y1: 1st thread, Y2: 2nd thread, Y3: 3rd thread, Y4: 4th thread Y1a, Y3a: Low strength yarn Y1b, Y3b: High strength yarn T: Tether thread, T1: First tether thread, T2: Second tether thread AT: A part of the area, or an area where the tether thread T intersecting with the first thread Y1 intersects with the third thread Y3

Claims

1. a first fabric layer in which first yarns extending in a first direction and second yarns extending in a second direction are interwoven in a cross-like manner; a second fabric layer in which third yarns extending in a first direction and fourth yarns extending in a second direction are interwoven crosswise; a tether yarn interwoven with the first yarn and the third yarn to connect the first fabric layer and the second fabric layer to each other; At least some of the first yarns and the third yarns include low-strength yarns and high-strength yarns arranged alternately in a second direction; A double woven fabric, wherein in the region where the tether yarn that crossed the first yarn crosses the third yarn, the tether yarn is woven so that it is hooked only on a low-strength yarn among the first yarns and a low-strength yarn among the third yarns.

2. The double-layered fabric of claim 1 , wherein upon expansion of the double-layered fabric, the force applied to the tether yarns causes the low-strength yarns to rupture.

3. The double woven fabric according to claim 1 , wherein the number of tether yarns is two or more.

4. The double-layered fabric according to claim 3, wherein, when observed in any one cross section of the double-layered fabric, two or more tether threads cross each other between the first and second fabric layers to form an X-shape.

5. The first yarns are composed of low-strength yarns and high-strength yarns arranged alternately in a second direction, and the first yarns cross the second yarns in pairs of one low-strength yarn and one high-strength yarn; or The double woven fabric of claim 1, wherein the third yarn is composed of low-strength yarns and high-strength yarns arranged alternately in the second direction, and the third yarns cross the fourth yarns in pairs, one low-strength yarn and one high-strength yarn.

6. the first yarns are composed of low-strength yarns and high-strength yarns arranged alternately in a second direction, and some of the first yarns cross the tether yarns in pairs, one low-strength yarn and one high-strength yarn; or The double woven fabric of claim 1, wherein the third yarns are composed of low-strength yarns and high-strength yarns arranged alternately in the second direction, and a portion of the third yarns are composed of one low-strength yarn and one high-strength yarn paired together and crossing the tether yarn.

7. the first yarn and the third yarn are composed of low-strength yarns and high-strength yarns arranged alternately in a second direction, and each of the first yarn and the third yarn is composed of one low-strength yarn and one high-strength yarn forming a pair and crossing the second yarn and the fourth yarn; At least a portion of the first yarns are composed of a pair of one low-strength yarn and one high-strength yarn that cross the tether yarn, and at least a portion of the third yarns are composed of a pair of one low-strength yarn and one high-strength yarn that cross the tether yarn, and The double woven fabric of claim 1, wherein in the region where the tether yarn that crossed the first yarn crosses the third yarn, the tether yarn is woven so that it is hooked only on a low-strength yarn among the first yarns and a low-strength yarn among the third yarns.

8. 2. The double woven fabric of claim 1, wherein when the number of high-strength yarns is n, the number of low-strength yarns is n+1.

9. the first yarns include low-strength yarns and high-strength yarns arranged alternately in a second direction in a portion of the region, and high-strength yarns in the remaining portion of the region, and the first yarns cross the second yarns in pairs of one low-strength yarn and one high-strength yarn in the remaining portion of the region, and the high-strength yarns cross the second yarns in the remaining portion of the region; or The double woven fabric of claim 1, wherein the third yarn comprises low-strength yarns and high-strength yarns arranged alternately in the second direction in some regions and high-strength yarns in the remaining regions, and in the some regions, the third yarn crosses the fourth yarn in pairs of one low-strength yarn and one high-strength yarn, and in the remaining regions, a high-strength yarn crosses the fourth yarn.

10. the first yarns include low-strength yarns and high-strength yarns alternately arranged in the second direction in some regions and high-strength yarns in the remaining regions, and in the remaining regions, the first yarns that are high-strength yarns cross the tether yarns; or 2. The double woven fabric of claim 1, wherein the third yarn comprises low-strength yarns and high-strength yarns arranged alternately in the second direction in some regions and high-strength yarns in the remaining regions, and in the remaining regions, the third yarns, which are high-strength yarns, intersect with the tether yarns.

11. the first and third yarns include low-strength yarns and high-strength yarns arranged alternately in the second direction in a partial region, and include high-strength yarns in the remaining region; in the partial region, the first and third yarns each form a pair of one low-strength yarn and one high-strength yarn, and cross the second and fourth yarns; and in the remaining region, the first and third yarns, which are high-strength yarns, cross the second and fourth yarns, respectively; In the remaining region, the first yarn, which is a high-strength yarn, intersects with the tether yarn, and the third yarn, which is a high-strength yarn, intersects with the tether yarn; The double woven fabric of claim 1, wherein in the region where the tether yarn that crossed the first yarn crosses the third yarn, the tether yarn is woven so that it is hooked only on a low-strength yarn among the first yarns and a low-strength yarn among the third yarns.

12. The double woven fabric of claim 1, wherein the first to fourth yarns and the tether yarn each independently comprise one or more fibers selected from polyester fiber, polyamide fiber, polyaramid fiber, polyketone fiber, carbon fiber, and cellulose fiber.

13. 10. The double-layer fabric of claim 1, wherein the low-strength yarns have a smaller fineness or lower tenacity than the high-strength yarns.

14. The double-weave fabric of claim 1 , wherein the high-strength yarn, the second yarn, and the fourth yarn comprise the same fiber.

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