Air bag

Abstract

To provide an air bag that can be easily reused and can suppress gas leakage at the time of expansion.SOLUTION: Provided is an air bag formed in a bag shape by cutting a base fabric 5 in a predetermined shape, the base fabric 5 being formed by weaving a multifilament as a raw yarn 6, and sewing edge parts by using a sewing thread. A particle that can suppress occurrence of aperture of a space between threads in the base fabric is adhered to a predetermined position of the base fabric. A particle 12 is set to have a particle diameter of substantially equal or less than an outer diameter dimension of a filament 6a forming the multifilament.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an airbag formed into a bag shape by cutting a base fabric woven using multifilament yarn into a predetermined shape and sewing the edges together using sewing thread. [Background technology]

[0002] Conventionally, woven fabrics made by plain weaving or the like using multifilament yarns have been used as base fabrics for airbags, but in airbags using such woven fabrics, when a load is applied during inflation, the stitches tend to shift, creating gaps between the stitches (easiness to cause openings), making it impossible to avoid gas leakage through the gaps between the stitches. Therefore, in order to prevent such gas leakage, silicone-coated fabrics, in which silicone resin is applied as a coating agent to the surface of the woven fabric, have been used as base fabrics for airbags.

[0003] Such silicone-coated fabric cannot be recycled as it is. Recently, in order to improve the recyclability of airbags using silicone-coated fabric, it has been proposed to remove the silicone coating from airbag scrap fabric at the time of scrapping of a vehicle, separate it from the polyamide fiber constituting the substrate, and recycle the substrate (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-180413 A [Patent Document 2] JP 2018-172618 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the method described in Patent Document 1, airbag scrap fabric is immersed in an alkaline solution to peel off the silicone coating from the scrap fabric, thereby separating the silicone coating from the polyamide fibers, which requires waste disposal of the alkaline solution and places a heavy burden on the environment.In addition, in the method described in Patent Document 2, airbag scrap fabric is immersed in an ethylene glycol solution and heated at high temperature, thereby dissolving the polyamide fibers constituting the substrate in the ethylene glycol solution and separating them from the silicone coating, which reduces the molecular weight of the recovered polyamide resin, making it difficult to reuse it as an airbag base fabric.

[0006] The present invention has been made to solve the above-mentioned problems, and has an object to provide an airbag that is easy to recycle and that can suppress gas leakage when inflated. [Means for solving the problem]

[0007] The airbag according to the present invention is formed into a bag shape by cutting a base fabric woven using multifilament yarn into a predetermined shape and sewing together the edges using a sewing thread, The fabric is configured such that particles capable of suppressing the occurrence of openings between stitches in the fabric are attached to predetermined locations on the fabric, The particles are characterized in that the particle diameter is set to be approximately equal to or smaller than the outer diameter of the filaments constituting the multifilament, and the amount of particles attached to the base fabric is set to be within the range of 1 to 35 weight % of the weight of the specified location on the base fabric where the particles are attached.

[0008] In the airbag of the present invention, particles are attached to predetermined locations on the base fabric. The particle diameter is set to be approximately equal to or smaller than the outer diameter of the filaments in the multifilament that constitute the base fabric. Therefore, when attached, the particles can easily penetrate not only between the filaments in the multifilament but also between the filaments that constitute the multifilament. Therefore, particles that penetrate between the filaments or between the stitches in the base fabric can act like wedges, effectively preventing the formation of gaps in the base fabric that would cause the stitches to shift. As a result, gas leakage is prevented, enabling the airbag to inflate quickly. Furthermore, because the particles are simply attached to the base fabric, they can be easily removed from the base fabric by shaking or hitting the airbag itself, or by vacuuming or rinsing the airbag with water. Furthermore, in the airbag of the present invention, the amount of particles attached to the base fabric is set within the range of 1 to 35 weight % of the weight of the specified location on the base fabric where the particles are attached. This makes it possible to appropriately prevent the occurrence of openings in the base fabric that cause the stitches to become misaligned, and also to prevent the stiffness of the base fabric to which the particles are attached from becoming too high.

[0009] Therefore, the airbag of the present invention can be easily recycled and can suppress gas leakage when inflated.

[0010] Specifically, in the airbag of the present invention, if the particles contain one of metal powder, silicon powder, synthetic resin powder, or talc powder, the particles are less likely to deteriorate due to weather conditions, etc., even when the airbag is installed in the vehicle for a long period of time, and when the airbag is inflated, the particles can accurately prevent openings from occurring in the base fabric, which is preferable.

[0011] Furthermore, in an airbag of the above configuration, if the particles are attached to the area around the stitching formed in the base fabric using stitching thread, this is preferable because it can accurately prevent openings from occurring in the area around the stitching, where tensile forces are likely to act upon inflation.

[0012] Furthermore, in the airbag having the above configuration, if the particles are attached to the base fabric so as to be detachable from the base fabric when the base fabric is washed with water, the particles can be removed from the base fabric simply by washing the base fabric with water, which is preferable as it allows the particles to be removed from the base fabric with a simple procedure. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a plan view of an airbag according to an embodiment of the present invention in a state where the airbag is deployed flat. [Figure 2] FIG. 2 is a schematic cross-sectional view of the airbag of FIG. 1. [Figure 3] FIG. 2 is a partially enlarged cross-sectional view showing the vicinity of a stitched portion in the airbag of FIG. 1. [Figure 4] 2 is a partially enlarged plan view showing the vicinity of a stitched portion in the airbag of FIG. 1 in an inverted state. [Figure 5] 2 is a schematic plan view showing a particle adhesion region in the airbag of FIG. 1. FIG. [Figure 6] 2 is a schematic cross-sectional view showing a particle adhesion region in the airbag of FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described below with reference to the drawings. In the embodiment, an airbag 1 for a driver's seat will be taken as an example of an airbag.

[0015] The airbag 1 is formed into a bag shape by cutting a base fabric 5 woven with multifilament yarn 6 into a predetermined shape and sewing the edges together using a sewing thread. In this embodiment, as shown in FIGS. 1 and 2 , the base fabric 5 is cut to have substantially identical circular shapes to form a vehicle body side wall 3 and an occupant side wall 2, and the bag shape is formed by sewing the outer peripheral edges 2a, 3a of the vehicle body side wall 3 and the occupant side wall 2 together using a sewing thread 8a. Specifically, the airbag 1 is folded and installed in a vehicle in an inverted state after sewing (see FIG. 2 ) so that the seam margins are not exposed, although detailed illustration is omitted. In addition, in the airbag 1 of this embodiment, particles 12 capable of suppressing the occurrence of gaps between the stitches 5a of the base fabric 5 are attached to predetermined locations on the base fabric 5 (see FIGS. 5 and 6 ). In detail, in the airbag 1 of the embodiment, the particles 12 are attached to the base fabric 5 within a particle attachment region 10 provided in the peripheral region of the stitching portion 8 that sews together the outer peripheral edges 2a, 3a of the vehicle body side wall portion 3 and the occupant side wall portion 2.

[0016] The base fabric 5 constituting the vehicle body side wall portion 3 and the occupant side wall portion 2 of the airbag 1 according to the embodiment is formed by weaving multifilaments as raw yarns 6. Specifically, the base fabric 5 is formed from a woven fabric woven from multifilaments made of polyamide (PA) fibers, polyester (PET) fibers, or polypropylene (PP) fibers as raw yarns. Specifically, in the embodiment, polyamide fibers are used for the base fabric 5. Specific examples of polyamide fibers that can be used include aliphatic polyamides such as nylon 66, nylon 6, nylon 46, and nylon 12, and aromatic polyamides such as aramid. More specifically, in the embodiment, the base fabric 5 is formed by weaving nylon 66 fibers using a plain weave. The weaving mode of the base fabric 5 is typically a plain weave, but is not limited to a plain weave. The base fabric 5 may also be woven using a twill weave, satin weave, or figured weave such as a jacquard weave.

[0017] In the airbag 1 of this embodiment, the filaments 6a (monofilaments) constituting the raw yarns 6 (multifilaments) of the base fabric 5 have an outer diameter of approximately 1 to 10 μm. In this embodiment, the base fabric 5 has a cover factor (K) expressed by the following formula (1) set within the range of 1750 to 2500 (preferably 1850 to 2350, and more preferably 2100 to 2300). If the cover factor (K) is less than 1750, the air permeability of the base fabric itself will be too high, and it will be difficult to obtain the required mechanical strength. Conversely, if the cover factor (K) exceeds 2500, the resulting base fabric will be too rigid and will not be able to be folded and stored well, both of which are undesirable for an airbag base fabric.

[0018] K=NW×DW 0.5 +NF×DF 0.5 (1) NW: Warp density (count / in), DW: Warp fineness (denier) NF: Weft density (counts / in), DF: Weft fineness (denier) A small or large cover factor (K) value means that the yarn density and / or yarn fineness of the warp and weft yarns in the base material are relatively small or large.

[0019] In the airbag 1, the seam 8 that sews together the outer peripheral edges 2a, 3a of the vehicle body side wall portion 3 and the occupant side wall portion 2 is configured in the present embodiment by providing a double-line seam 8b that is continuously arranged around the entire circumference, as shown in Figures 3 and 4. In the airbag 1 of the present embodiment, the seam thread 8a that forms this seam 8 is also made of polyamide (PA) fiber, polyester (PET) fiber, or polypropylene (PP) fiber, like the base fabric 5 that forms the airbag 1. Specifically, in the present embodiment, the seam thread 8a is made of nylon 66 fiber, the same as the base fabric 5 that forms the airbag 1.

[0020] In the airbag 1 of the embodiment, the particle attachment region 10 where the particles 12 are attached to the base fabric 5 is formed from the region around the stitching region 8, as described above. In the case of the embodiment, the particle attachment region 10 is formed in a substantially band-shaped region that covers both sides of the stitching region 8, including the stitching region 8, as shown in FIGS. 3 and 4 , and is formed around the entire circumference of the stitching region 8. In the airbag 1 of the embodiment, the particle attachment region 10 is formed by applying or spraying a dispersion liquid in which the particles 12 are dispersed in a solvent such as water or ethanol that evaporates after attachment to the inner surfaces 2b, 3b of the vehicle body side wall 3 and the occupant side wall 2, thereby attaching the particles 12 within this region. Alternatively, the particles 12 may be attached by directly spraying them onto the particle attachment region 10 without using a solvent. Specifically, the particle attachment region 10 is configured to have a width dimension W (see FIG. 4 ) of about 5 mm (preferably about 7 mm) on both sides of the stitching region 8.

[0021] The particles 12 are attached to the base fabric 5 to prevent the formation of gaps between the stitches 5a in the base fabric 5. As shown in FIGS. 5 and 6, the particles 12 are attached to the base fabric 5 so as to penetrate between the stitches 5a in the base fabric 5 and between the filaments 6a (monofilaments) constituting the raw yarn 6 (multifilament). The particle diameter of the particles 12 is set to be approximately equal to or smaller than the outer diameter of the filaments 6a (monofilaments) constituting the base fabric 5. Specifically, it is preferable to use particles 12 with a particle diameter set to 15 μm or less (preferably, about 5 to 10 μm). This is because if the particle diameter exceeds 15 μm, the particles can penetrate between the stitches 5a but will not smoothly penetrate between the filaments 6a. The particles 12 are formed from a material having a hardness that allows them to wedge-likely between the filaments 6a when they penetrate between the filaments 6a or between the stitches 5a. Specifically, the particles 12 are preferably formed from a material having a Mohs hardness in the range of approximately 0.8 to 5 (preferably 1 to 3). A Mohs hardness of less than 0.8 makes the particles 12 too soft and makes it difficult for them to maintain their wedged state between the filaments 6a. Conversely, a Mohs hardness of more than 5 makes the particles 12 too hard and makes it difficult for them to wedge between the filaments 6a. Furthermore, since the particles 12 are to be used in airbags that will be installed in vehicles for extended periods, they are preferably formed from an inorganic or synthetic material whose physical properties are unlikely to change due to weather conditions or the like. Specifically, the particles 12 are preferably formed from a material containing any one of metal powders such as iron powder, silicon powder, powders of synthetic resins such as nylon 66, and talc powder. In this embodiment, the particles 12 are formed from talc powder. The amount of particles 12 attached to the base fabric 5 is preferably set within the range of 1 to 35% by weight (preferably 1 to 25% by weight, and more preferably 1 to 20% by weight). If the amount is less than 1% by weight, the amount attached to the base fabric 5 is too small and it is difficult to obtain a sufficient effect of suppressing opening of the mesh. Conversely, if the amount exceeds 35% by weight, it is too much and the flexibility of the particle-attached regions 10 decreases (the bending resistance of the particle-attached regions 10 becomes too high), making it unsuitable as a base fabric for an airbag and also making it difficult to obtain further effects.

[0022] Furthermore, in the airbag 1 of this embodiment, the particles 12 are attached to the base fabric 5 so as to be detachable from the base fabric 5 when the base fabric 5 is washed with water. Specifically, if the base fabric 5 having the particles 12 attached thereto is immersed in water (warm water) at a temperature of 5 to 35°C (preferably 10 to 35°C) and then stirred at a stirring speed of 1 to 1500 rpm (preferably 60 to 1500 rpm) for 1 to 60 minutes (preferably 1 to 30 minutes), 90% or more (preferably 95% or more) of the particles 12 can be detached from the base fabric 5. As described above, the particles 12 are attached to the base fabric 5 simply by penetrating between the stitches 5a in the base fabric 5 and between the filaments 6a constituting the yarn 6 (multifilament), and therefore, in addition to being removed by washing with water, the particles 12 can be separated to a certain extent from the base fabric 5 by shaking or hitting the airbag 1 or by suction using a vacuum cleaner or the like.

[0023] Next, the results of a slippage resistance test (ASTM D 6479) of the particle adhesion region of the base fabric constituting the airbag of the embodiment will be described. The base fabric used was a woven fabric made of nylon 66 (plain weave: 470 dtex, 55 thread count, cover factor: 2262). The base fabric of the test example had talc powder particles with a particle diameter of approximately 10 μm attached to one side at a rate of 20% by weight. As a comparative example, the slippage resistance of the same base fabric without particles attached was also measured. The average slippage resistance value of the test example base fabric after eight measurements was 850 N, while the average slippage resistance value of the comparative example base fabric after five measurements was 581 N. The base fabric of the test example to which particles were attached (particle-attached region 10 in base fabric 5 of airbag 1 of the embodiment) had a higher slippage resistance value than the base fabric of the comparative example (general region to which particles were not attached in base fabric 5 of airbag 1 of the embodiment), and the slippage resistance value was increased by 46% compared to the base fabric of the comparative example. In other words, the base fabric to which particles were attached was less likely to develop openings than the base fabric to which particles were not attached.

[0024] In the airbag 1 of this embodiment, particles 12 are attached to predetermined locations on the base fabric 5. The particle diameter of the particles 12 is set to be approximately equal to or smaller than the outer diameter of the filaments 6a in the multifilament (yarn 6) constituting the base fabric 5. This allows the particles 12 to easily penetrate not only between the yarns 6 made of the multifilament but also between the filaments 6a constituting the multifilament. As a result, as shown in FIGS. 5 and 6 , the particles 12 that have penetrated between the filaments 6a and between the loops 5a in the yarn 6 act like wedges, effectively preventing the base fabric 5 from having gaps that would displace the loops 5a. As a result, gas leakage is prevented, allowing the airbag 1 to inflate quickly. Furthermore, because the particles 12 are simply attached to the base fabric 5, they can be easily removed from the base fabric 5 by shaking or hitting the airbag 1 itself, or by vacuuming or washing the airbag 1 with water.

[0025] Therefore, the airbag 1 of the embodiment can be easily recycled and can suppress gas leakage when inflated.

[0026] Specifically, the airbag 1 of this embodiment uses particles 12 containing one of metal powder, silicon powder, synthetic resin powder, and talc powder. Therefore, even if the airbag 1 is mounted in a vehicle for a long period of time, the particles are unlikely to deteriorate due to weather conditions, etc., and when the airbag 1 is inflated, the particles 12 can effectively prevent openings from occurring in the base fabric 5.

[0027] Furthermore, in the airbag 1 of the embodiment, the amount of particles 12 attached to the base fabric 5 is set within the range of 1 to 35% by weight of the base fabric 5, so that the amount of particles 12 attached to the base fabric 5 is appropriate, and the occurrence of openings in the base fabric 5 that cause the stitches to shift can be accurately suppressed, and the stiffness of the base fabric 5 to which the particles 12 are attached can be prevented from becoming too high.

[0028] Furthermore, in the airbag 1 of the embodiment, the particles 12 are attached to the area around the stitching 8 formed in the base fabric 5 using the stitching thread 8a, which effectively prevents the formation of openings in the area around the stitching 8, which is susceptible to tensile force during inflation. Conversely, in the airbag 1 of the embodiment, the particles 12 are not attached to areas away from the stitching 8, which effectively prevents the particles 12 from affecting the performance of the base fabric 5 of the airbag 1 (such as the flexibility of the base fabric itself). Of course, if this point is not taken into consideration, the particles may be attached to areas away from the stitching, or may be attached over substantially the entire area, including the area around the stitching.

[0029] In the airbag 1 of the embodiment, the particles 12 are configured to be attached to the inner surfaces 2b, 3b of the vehicle body side wall 3 and the occupant side wall 2 by providing particle attachment regions 10 on the inner surfaces 2b, 3b of the base fabric 5 (vehicle body side wall 3, occupant side wall 2). In other words, the particles are attached by being applied from only one side of the base fabric 5. The manner in which the particles are attached is not limited to the embodiment, and the particles may be attached by being applied from both sides of the base fabric. In the airbag 1 of the embodiment, the particle diameter of the particles 12 is set to be approximately equal to or smaller than the outer diameter of the filaments 6a in the multifilament (raw yarn 6) constituting the base fabric 5. Therefore, even if the particles are applied (sprayed, etc.) from only one side, they can smoothly enter gaps between the filaments 6a separated from the surface of the base fabric 5, thereby achieving a good effect of suppressing opening.

[0030] Furthermore, in the airbag 1 of the embodiment, the particles 12 are configured to be attached to the base fabric 5 so as to be detachable from the base fabric 5 when the base fabric 5 is washed with water. Therefore, the particles 12 can be removed from the base fabric 5 simply by washing the base fabric 5 with water, and the particles can be removed from the base fabric with a simple procedure. [Explanation of symbols]

[0031] 1...airbag, 5...base fabric, 5a...thread, 6...original yarn (multifilament), 6a...filament, 8...sewing portion, 8a...suture thread, 12...particles

Claims

1. An airbag formed into a bag shape by cutting a base fabric woven using multifilament yarn into a predetermined shape and sewing together the edges with a sewing thread, Particles capable of suppressing the occurrence of openings between stitches in the base fabric are attached to predetermined locations in the base fabric, The particles have a particle diameter set to be approximately equal to or smaller than the outer diameter of the filaments constituting the multifilament, and the amount of the particles attached to the base fabric is set to be within the range of 1 to 35% by weight of the weight of the predetermined location on the base fabric where the particles are attached.

2. 2. The airbag according to claim 1, wherein the particles contain one of metal powder, silicon powder, synthetic resin powder, and talc powder.

3. 2. The airbag according to claim 1, wherein the particles are attached to the base fabric in a peripheral region of a seam formed using the seam.

4. 2. The airbag according to claim 1, wherein the particles are attached to the base fabric so as to be removable from the base fabric when the base fabric is washed with water.

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