Woven fabric for airbag, manufacturing method for woven fabric for airbag and airbag

Abstract

To provide a woven fabric for an airbag having a low flare height, and a manufacturing method for the woven fabric for an airbag that is easy to pass through processing steps and that can suppress wrinkles.SOLUTION: A woven fabric for an airbag has a ground part and a selvedge part, and includes an additional yarn as a warp yarn in the selvage part, the additional yarn being monofilament having a fineness of 33 dtex or less, and each selvage part contains four or more additional yarns, the ratio (B / A) of an average warp crimp rate A at the center of the woven fabric to the average warp crimp rate B at a position 50 mm from the end part of the woven fabric is 0.90 or more and 1.10 or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a fabric for an airbag, a method for manufacturing the fabric for an airbag, and an airbag.

Background Art

[0002] Automobiles are equipped with airbags for ensuring the safety of passengers. When an impact is detected by a sensor during a collision accident or the like of an automobile, high-temperature and high-pressure gas is generated, and the airbag is instantaneously inflated by this gas to protect the face, head, etc. of the passenger from the collision.

[0003] An airbag is generally a base fabric (coated base fabric) obtained by applying a silicone resin or the like for improving characteristics such as heat resistance, flame retardancy, and air barrier property to a plain fabric using synthetic fiber filaments of 150 to 600 dtex. This base fabric is cut and sewn into a bag body.

[0004] In addition, there is also a so-called non-coated base fabric that is used by weaving synthetic fiber filaments at a high density without applying a silicone resin or the like to reduce the air permeability of the fabric.

[0005] Here, the fabric for an airbag is required to have high strength and low air permeability in order to instantaneously inflate the airbag during a collision accident of an automobile and protect the face, head, knees, etc. of the passenger during a collision. For this reason, the fabric for an airbag needs to use a stronger yarn and be a higher-density fabric compared to ordinary clothing fabrics.

[0006] In addition, air vents (vent holes) for adjusting the internal pressure of the airbag are provided in the driver protection airbag and the passenger seat protection airbag that mainly use non-coated base fabrics, and are intended to appropriately adjust and maintain the internal pressure. However, if there is variation in the air permeability of the non-coated base fabric, there is a concern that the predetermined internal pressure cannot be adjusted and maintained at the vent hole. Therefore, a uniform air permeability is required for the base fabric used for the airbag.

[0007] Generally, when weaving this high-density fabric, for example, in the case where the warp and weft are 470 dtex and the fabric density of the warp and weft is 55 per inch (2.54 cm) for both warp and weft in a plain weave structure, the higher the weft density, the greater the amount by which the fell of the fabric before weaving moves to the warp delivery side from the foremost position of the reed. As a result, the following disadvantages (a) to (e) are likely to occur.

[0008] (a) When beating the reed, the fabric near the fell before weaving causes a bumping phenomenon, making it difficult to obtain a fabric with the desired weft density.

[0009] (b) After the weft is beaten in, the weft is cut by a cutter at each of the left and right ends before weaving. At this time, the cut weft is not gripped and becomes free, increasing the weft crimp at both ear ends of the base fabric, and conversely decreasing the warp crimp at the ear ends. Therefore, the warp tension at both ears decreases compared to the ground part of the fabric. As a result, the gripping force of the warp on the weft decreases, and the fells at both ear ends before weaving retreat. Consequently, the warp at the ears loosens and a flare occurs.

[0010] (c) When the loom rotation speed is increased, the phenomenon of the fell at the ear ends retreating becomes more prominent. Due to the warp loosening at the ear ends of the base fabric, a difference in fabric length occurs between the ear ends and the central part, and a flare (also called "ear flapping") in which the ear ends are wavy occurs. The base fabric for the airbag is cut and sewn into a bag shape. To make the most effective use of the base fabric for the airbag, a cutting pattern is designed and usually used up to the ear ends or the vicinity thereof. Since the edges of the cut pieces are likely to fray, if a flare occurs near the ear ends, cutting defects are likely to occur. As a result, misalignment occurs, and the desired accurate shape as an airbag cannot be obtained, and the required functions are also lost.

[0011] (d) Flare in the green state not only hinders the processability during rolling and subsequent refining and setting processes but also causes wrinkles. When the resin is coated, the flare not only hinders the processability of the coating process but also causes uneven coating amounts and wrinkles in the coating resin.

[0012] (e) Due to the warp slack in the ear part in the green state, the crimp structures of the central part and the ear part of the fabric are different, resulting in a difference in air permeability between the central part and the ear part of the fabric, and a uniform airbag in the width direction cannot be obtained.

[0013] As various attempts to prevent the above-mentioned disadvantages (a) to (e), for example, in a fabric for an airbag made of synthetic fiber, a weaving method is described in which the warp tension in the ear part is made 1.2 times or more higher than the warp tension in the ground part. (Patent Document 1). Thereby, the force with which the warp in the ear part grips the weft increases, and the flare is suppressed.

[0014] Also, a method of reducing the variation in air permeability in the width direction of the base fabric by adjusting the temperature before the heat setting process is also known (Patent Document 2). It is described that the uniformity of the air permeability in the width direction is improved by this method.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0016] Although the technique disclosed in Patent Document 1 tends to suppress flare, the tension of the ear warp is too high compared to the tension of the ground warp, resulting in a state of ear suspension. Therefore, pin detachment may occur in the heat setting process, raising concerns about a decrease in the processability through the processing steps.

[0017] In addition, in the technique disclosed in Patent Document 2, since the tension of the ear warp is lower than that of the ground warp during weaving, flare is likely to occur. Also, wrinkles may occur due to this.

[0018] From the above viewpoints, there is a need for an airbag fabric with a low flare height, as well as a method for manufacturing an airbag fabric with good processability through processing steps and few wrinkles. The present invention has been made in view of such conventional problems, and an object thereof is to provide an airbag fabric with a low flare height. Another object is to provide a method for manufacturing an airbag fabric that is excellent in processability through processing steps and can suppress wrinkles.

Means for Solving the Problems

[0019] The airbag fabric, the method for manufacturing an airbag fabric, and the airbag of the present invention for solving the above problems are composed of the following configurations. (1) An airbag fabric having a ground portion and ear portions, and including thickened yarns as the warps of the ear portions, wherein the thickened yarns are monofilaments with a fineness of 33 dtex or less, and each ear portion contains 4 or more of the thickened yarns, and the ratio (B / A) of the average warp crimp rate A at the central portion of the fabric to the average warp crimp rate B at a position 50 mm from the end of the fabric is 0.90 or more and 1.10 or less. (2) The airbag fabric according to (1), wherein the CV value of the warp crimp rate per 20 cm in the weft direction is 3.0% or less. (3) The airbag fabric according to (1) or (2), wherein the CV value of the air permeability at a differential pressure of 20 kPa according to JIS L1096 (1996) is 10% or less. (4) The airbag fabric according to any one of (1) to (3), wherein the total fineness of the multifilaments constituting the fabric is 200 to 470 dtex. (5) The airbag fabric according to any one of (1) to (4), wherein the cover factor of the fabric is 2000 to 2500. (6) In the weaving process, four or more warp yarns made of monofilaments with a fineness of 33 dtex or less are used at the ends of the fabric, and the tension of the warp yarns relative to the tension of the ears is adjusted to be 1.20 times or more and 1.50 times or less. A method for manufacturing an airbag fabric according to any one of (1) to (5). (7) In the weaving process, the warp tension of the ears is adjusted to be in the range of 0.80 to 1.20 times the warp tension of the ground part. A method for manufacturing an airbag fabric according to (6). (8) An airbag in which the airbag fabric according to any one of (1) to (5) is sewn. [Advantages of the Invention]

[0020] According to the airbag fabric of the present invention, it has the effect of low flare height. Further, according to the method for manufacturing an airbag fabric, it is possible to provide an airbag fabric that is excellent in passing through the processing step and suppresses the generation of wrinkles in the ears. [Embodiments for Carrying Out the Invention]

[0021] [Airbag Fabric] The airbag fabric according to an embodiment of the present invention (hereinafter, also simply referred to as a fabric) has a ground part and ears, and is an airbag fabric containing warp yarns as ears, wherein the warp yarns are monofilaments with a fineness of 33 dtex or less, and each ear contains four or more of the warp yarns, and the ratio (B / A) of the average warp crimp rate A at the center of the fabric to the average warp crimp rate B at a position 50 mm from the end of the fabric is 0.90 or more and 1.10 or less.

[0022] Generally, the ears of the fabric refer to the portion within 100 mm from the ear end of the fabric. In this embodiment, the "ears" refer to the portion within 25 mm from the ear end of the fabric. Further, in this embodiment, the "ground part" refers to the central part of the fabric sandwiched between the ears.

[0023] The airbag fabric of this embodiment is mainly composed of multifilament polyamide fibers. Examples of the composition of the polyamide fibers according to this embodiment include nylon 6, nylon 6,6, nylon 12, nylon 4,6, nylon 4,10, nylon 6,10, copolyamide of nylon 6 and nylon 6,6, and copolyamide obtained by copolymerizing polyalkylene glycol, dicarboxylic acid, amine, etc. with nylon 6. The composition of the polyamide fiber is preferably a fiber made of nylon 6 or nylon 6,6 in terms of excellent impact resistance of the resulting airbag.

[0024] In the present invention, the total fineness of the polyamide fiber is not limited, but is preferably 235 dtex or more, and more preferably 280 dtex or more. Also, the total fineness of the multifilament is preferably 470 dtex or less. When the total fineness of the multifilament is 235 dtex or more, the resulting fabric is likely to obtain necessary mechanical properties (such as tensile strength and tear strength). On the other hand, when the total fineness of the multifilament is 470 dtex or less, the resulting fabric is likely to obtain lightness and compactness. The total fineness of the polyamide fiber is calculated based on JIS L1013 (1999) 8.3.1 Method A.

[0025] Also, in the present invention, the single-fiber fineness of the polyamide fiber is not particularly limited, but is preferably 1.0 dtex or more, more preferably 1.5 dtex or more, and even more preferably 2.0 dtex or more. Also, the single-fiber fineness of the polyamide fiber is preferably 8.0 dtex or less, and more preferably 7.0 dtex or less. By setting the single-fiber fineness of the polyamide fiber to 1.0 dtex or more, it is possible to suppress breakage of single fibers during production, and it is easy to manufacture. Also, by setting the single-fiber fineness of the polyamide fiber to 8.0 dtex or less, the flexibility of the resulting warp and weft is improved. The single-fiber fineness of the polyamide fiber is calculated by dividing the total fineness by the number of filaments. The number of filaments is calculated based on the method of JIS L1013 (1999) 8.4.

[0026] In the present invention, the number of filaments of the polyamide fiber is not particularly limited, but is preferably 44 to 144, more preferably 72 to 136. If the number of filaments of the polyamide fiber is 44 or more, the amount of air ventilating between single fibers is reduced, and a predetermined degree of air permeability is easily obtained. On the other hand, if the number of filaments of the polyamide fiber is 144 or less, the single fiber fineness becomes thick, so that it is less likely to be damaged by rubbing against guides, reeds, etc. during warping and weaving, and fluff and the like due to rubbing are less likely to occur in the warp, improving productivity.

[0027] The cross-sectional shape of the single fiber of the polyamide fiber is not particularly limited. For example, the cross-sectional shape of the single fiber may be circular, or may be various non-circular shapes such as X-shaped, C-shaped, Y-shaped, V-shaped, flat-shaped, etc., or may have a hollow portion. Among these, from the viewpoint of yarn manufacturing property, the cross-sectional shape of the single fiber is preferably circular.

[0028] The tensile strength of the polyamide fiber of the present invention is preferably 8.0 cN / dtex or more, more preferably 8.4 cN / dex or more as a multifilament. If the tensile strength of the polyamide fiber is 8.0 cN / dtex or more, the obtained fabric has sufficient mechanical properties (such as tensile strength and tear strength). On the other hand, the upper limit of the tensile strength is not particularly limited. The tensile strength of the polyamide fiber is calculated by measuring under the constant speed elongation conditions shown in the JIS L1013 (1999) 8.5.1 standard test.

[0029] The elongation of the polyamide fiber in the present invention is preferably 20% or more, more preferably 21% or more as a multifilament. Also, the elongation of the polyamide fiber is preferably 25% or less, more preferably 24% or less. When the elongation of the polyamide fiber is within the above range, the obtained fabric is excellent in toughness and work to break. Also, polyamide fibers showing elongation within the above range can improve yarn manufacturing property and weaving property. The elongation of the polyamide fiber can be calculated based on the elongation at the point showing the maximum strength in the S-S curve obtained when calculating the above tensile strength.

[0030] The polyamide fiber of the present invention may be appropriately blended with additives such as heat stabilizers, antioxidants, light stabilizers, smoothing agents, antistatic agents, plasticizers, thickeners, pigments, and flame retardants in order to improve productivity in the spinning, drawing, and processing steps or the properties of the resulting fabric.

[0031] The fabric for an airbag according to the present invention may be plain weave, twill weave, satin weave, or variations thereof, but is not particularly limited to these.

[0032] The weave density of the airbag fabric according to the present invention may vary depending on whether the fabric is resin-treated or not, the fineness of the weaving yarn, etc. Therefore, in the present invention, the cover factor is used as an index. For example, a cover factor of 2000 to 2500 is preferable to achieve both low breathability and high slippage resistance. Generally, when the cover factor is 2000 to 2500, the recession of the selvedge end, which is a problem during weaving, becomes significant, and flare also becomes pronounced. However, the present invention can be effectively applied to fabrics with a cover factor of less than 2000 or more than 2500, but the above-mentioned effects are particularly likely to be achieved when the fabric has a cover factor of 2000 to 2500.

[0033] Here, the cover factor is calculated by the following formula, where the total warp fineness is D1 (dtex), the warp density is N1 (counts / 2.54 cm), the total weft fineness is D2 (dtex), and the weft density is N2 (counts / 2.54 cm). Cover factor = (D1 x 0.9) 1 / 2 ×N1+(D2×0.9) 1 / 2 ×N2 It is expressed as:

[0034] The airbag fabric according to this embodiment includes a tangling yarn and an additional yarn at the selvage edge. In addition, selvage fastening yarn may also be used.

[0035] The "twisted yarn" is also called leno. At the outermost part of the ear of the fabric, multiple yarns are intertwined while clamping the weft yarn, thereby preventing ear fraying. The material, type, and fineness of the twisted yarn are appropriately selected according to the type of ground yarn and the weaving density. The number of yarns used is preferably two or more at each of both ends. Generally, a monofilament with excellent ear-clamping performance is used for the twisted yarn. In this embodiment, the twisted yarn may be a monofilament or a multifilament. Preferably, the material of the twisted yarn is the same as that of the ground yarn. When the twisted yarn is a monofilament, its fineness is preferably 33 dtex or less. If the fineness of the twisted yarn is 33 dtex or less, fraying is less likely to occur at the ear of the fabric. The fineness of the twisted yarn is preferably 5 - 22 dtex.

[0036] The "yarn increment" is used for the purpose of preventing fraying of the ear of the fabric, similar to the twisted yarn, and is arranged between the twisted yarn and the warp yarn at the ear of the fabric. The yarn increment is preferably a plain weave with excellent ear-clamping property. Also, the material, type, and fineness of the yarn increment are appropriately selected according to the type of ground yarn and the weaving density. A monofilament with excellent ear-clamping performance is preferably used for the yarn increment. When the yarn increment is not included or the number of yarn increments is small, ear fraying is likely to occur and the flare height cannot be lowered. Therefore, it is necessary that the number of yarn increments includes four or more at each of both ends. On the other hand, the upper limit of the number of yarn increments is not particularly limited, but considering productivity and cost, 12 or less is preferable. The yarn increment must be a monofilament of 33 dtex or less. When the fineness of the yarn increment exceeds 33 dtex, fraying may occur at the ear of the fabric. The finer the fineness of the yarn increment, the more fraying is suppressed and the ear-clamping property is excellent, so that the flare height can be lowered. Therefore, the fineness of the yarn increment is preferably 22 dtex or less. On the other hand, the lower limit of the fineness of the yarn increment is not limited, but as an example, it is 5 dtex.

[0037] The "ear tightening thread" may be used for the purpose of preventing flare of the fabric, separately from the interlacing thread and the weft increase thread, and is arranged between the weft increase thread and the warp thread at the ear part of the fabric. Similar to the weft increase thread, a planetary device is not used. It is preferably used in a plain weave with excellent ear tightening property. The material, type, and fineness of the ear tightening thread are appropriately selected according to the type of the ground thread and the weaving density, respectively. The ear tightening thread is preferably a multifilament having a total fineness of 80% or more of the total fineness of the ground thread in order to perform weaving under high tension. When the total fineness is less than 80% of the ground thread, it is impossible to perform weaving under high tension, and the flare prevention effect cannot be obtained. The number of ear tightening threads used is, for example, 4 to 8 at each of both ends.

[0038] In the fabric for airbag of the present invention, the ratio (B / A) of the average warp crimp rate A at the center of the fabric to the average warp crimp rate B at the position 50 mm from the end of the fabric is 0.90 or more and 1.10 or less.

[0039] Here, the center of the fabric refers to the central portion in the width direction of the fabric. For example, when the width of the fabric is 2.00 m, the range from 0.95 m to 1.01 m from the end of the fabric is defined as the center of the fabric. Also, the method for measuring the average warp crimp rate A at the center of the fabric is as follows: First, 10 arbitrary ground warp threads are sampled at the center of the fabric. Subsequently, the crimp rate is measured by the method described in the examples, and the arithmetic mean value is calculated for measurement. Also, the method for measuring the average warp crimp rate B at the position 50 mm from the end of the fabric is as follows: 5 warp threads each are sampled from the positions 50 mm from both ends of the fabric, for a total of 10 warp threads. Subsequently, the crimp rate is measured, and the arithmetic mean value is calculated for measurement.

[0040] When the ratio (B / A) of the average warp crimp rate A at the center of the fabric to the average warp crimp rate B at the position 50 mm from the end of the fabric is less than 0.90, the ear warp becomes loose and the flare height increases. Therefore, the ratio (B / A) of the average warp crimp rate A to the average warp crimp rate B is preferably 0.95 or more.

[0041] When flare occurs in the weaving process, wrinkles are likely to occur from the ear ends to the ground part side during winding or in subsequent scouring or heat setting processes. In that case, there is a risk that the physical properties of the fabric for airbags may change, or that part misalignment may occur in the cutting process of the fabric for airbags. On the other hand, as described above, the fabric for airbags of the present embodiment has the effect of reducing the flare height and making it difficult for wrinkles to occur.

[0042] Also, when the ratio (B / A) of the average warp crimp rate A to the average warp crimp rate B exceeds 1.10, ear hanging is likely to occur, and pin detachment is likely to occur in the heat setting process. Therefore, the ratio (B / A) of the average warp crimp rate A to the average warp crimp rate B is preferably 1.05 or less.

[0043] In the fabric for airbags according to the present invention, it is preferable that the CV value of the warp crimp rate of the fabric measured by the JIS L1096 (2010) 8.7 B method every 20 cm in the weft direction of the fabric is 3.0% or less. Here, the warp crimp rate of the fabric is measured at a point 50 mm from any ear end of the fabric, and based on that point, warps are sampled every 20 cm in the weft direction, and the warp crimp rate is measured. If the CV value of the warp crimp rate of the fabric is 3.0% or less, the slack of the ear warps is suppressed, and the flare height is reduced. Therefore, it becomes difficult for wrinkles to occur in the scouring and heat setting processes, and it is difficult for parts to be affected during cutting. Also, due to the cutting position of the fabric used for the airbag, variations in the internal pressure performance are less likely to occur. The CV value can usually be calculated by measuring in the entire width direction of the fabric. When the width of the fabric is short, at least 5 or more measurement points are sufficient.

[0044] Since the fabric of the present embodiment has a low flare height, the width of the ear part is smaller compared to a general fabric for airbags. Thereby, the ratio of the ground part in the width direction of the fabric increases. Therefore, there is also an effect of small variation in performance in the width direction as the fabric for airbags.

[0045] The woven fabric of this embodiment preferably has a coefficient of variation (CV value) of the air permeability at a differential pressure of 20 kPa according to JIS L1096 (1999) measured every 20 cm in the weft direction of the woven fabric of 10.0% or less. If it is below the above-mentioned CV value, variations in the internal pressure performance may occur due to the cutting position of the woven fabric used for the airbag, the size of the airbag cushion, the type of inflator, the acceleration difference of the occupant, etc. In addition, when the width of the woven fabric is short, at least 5 measurement points are sufficient.

[0046] [Manufacturing Method of Woven Fabric for Airbag] The manufacturing method of the woven fabric for airbag of the present invention (hereinafter, also simply referred to as the manufacturing method of the woven fabric) is the manufacturing method of the above-mentioned woven fabric (woven fabric for airbag) of the present invention. The manufacturing method of the woven fabric for airbag of the present invention is characterized in that in the weaving process, 4 or more end - threads made of monofilaments with a total fineness of 33 dtex or less are used at the end of the woven fabric, and the tension of the end - threads is 1.20 times or more higher than the tension of the ear part. Therefore, the other processes shown below are all examples and may be replaced by other known processes.

[0047] According to the manufacturing method of the woven fabric for airbag of the present invention, first, the warp threads with the above - mentioned total fineness related to the woven fabric are warped and installed on the loom. Similarly, the weft threads are installed on the loom.

[0048] The loom is not particularly limited, but when weaving a high - density woven fabric, it is preferable to use a loom equipped with a full - width temple device. Examples of the loom include a water - jet loom, an air - jet loom, a rapier loom, etc. Among these, from the viewpoint that high - speed weaving is relatively easy and productivity can be easily increased, the water - jet loom is preferable as the loom.

[0049] When weaving, the tension applied to each warp (multifilament) constituting the ground portion of the fabric is preferably adjusted to be in the range of 0.20 to 0.50 cN / dtex. When the warp tension is within the above range, the resulting fabric can improve its dimensional stability by reducing the voids between the single fibers in the yarn bundle of the multifilaments constituting the fabric. When the warp tension is less than 0.20 cN / dtex, the restraining force of the weft during weaving is low, and it is difficult to obtain a fabric with the same density of warp and weft. On the other hand, when the warp tension is 0.50 cN / dtex or less, in the fabric, the contact area (adhesion) between the warp and the weft is likely to be small. Therefore, the warp is less likely to have hairiness, and the weaving property is improved. The method for adjusting the warp tension is not particularly limited. For example, the warp tension can be adjusted by a method of adjusting the warp feed speed of the loom, a method of adjusting the driving density of the weft, etc. Whether the warp tension is within the above range can be confirmed, for example, by measuring the tension applied to each warp with a tension measuring device at the central part of the warp beam and the back roller during the operation of the loom.

[0050] In the method for manufacturing a fabric for an airbag of the present invention, it is preferable to adjust the warp tension of the fabric ear part woven by a loom to be in the range of 0.80 to 1.20 times the warp tension of the ground part and then perform weaving. Further, it is more preferable to adjust the warp tension of the fabric ear part to be in the range of 0.90 to 1.10 times that of the warp tension of the ground part, and even more preferably in the range of 0.95 to 1.05 times. Generally, when weaving a high-density fabric with the supply of the ground part and the warp from the same beam, the tension of the ear warp decreases compared to the ground warp (for example, the tension of the ear warp may be less than 0.8 with respect to the tension of the ground warp), so flare is likely to occur. Therefore, in order to suppress flare, it is preferable to prevent the tension of the ear warp from decreasing. That is, by controlling so that the tension of the ear warp does not decrease during weaving and approaching the tension of the ground warp, the crimp ratio of the ear warp and the crimp ratio of the ground warp become uniform. Thereby, the occurrence of flare is efficiently suppressed, the air permeability uniformity in the width direction is obtained, and the process passability of the scouring and heat setting processes is also good.

[0051] The method for adjusting the warp tension of the fabric ear part to a range of 0.90 to 1.10 times that of the ground part warp tension is not particularly limited. For example, a method of supplying warp threads one by one from a paper tube, bobbin, etc. and managing the tension with a tenser such as a spring washer, a method of preparing a beam for weaving the ear part separately from the warp beam and controlling the tensions of the ground part warp and the ear part warp respectively, a method of changing only the winding tension of the threads of the ear part when warping the warp beam, etc. can be used for adjustment.

[0052] (Winding thread, increasing thread, ear tightening thread) In this embodiment, in the weaving process, four or more increasing threads made of monofilaments of 33 dtex or less are used at the ends of the fabric. Here, when no increasing thread is used in the weaving process or the number of increasing threads is small, the gripping force of the weft thread is low, so the flare height becomes high. Therefore, it is necessary to use four or more increasing threads at both ends respectively. On the other hand, although the upper limit of the number of increasing threads is not particularly limited, considering productivity and cost, 12 or less is preferable.

[0053] The increasing thread needs to be a monofilament of 33 dtex or less. When the fineness of the increasing thread exceeds 33 dtex, fraying may occur at the ear part of the fabric. The finer the fineness of the increasing thread, the more fraying is suppressed and the ear tightening property is excellent, so the flare height can be lowered. Therefore, the fineness of the increasing thread is preferably 22 dtex or less. On the other hand, the lower limit of the fineness of the increasing thread is not limited, but as an example, it is 5 dtex.

[0054] In the weaving process, it is preferable to adjust the tension of the increasing thread relative to the tension of the ear part to be 1.20 times or more and 1.50 times or less. If the tension of the increasing thread is 1.20 times or more than the tension of the ear part, the force with which the increasing thread grips the weft thread increases. Therefore, the tension of the ear part warp increases more than that of the ground part warp, and the flare height becomes lower. Therefore, it is more preferable to adjust the tension of the increasing thread relative to the tension of the ear part to be 1.30 times or more. On the other hand, the lower the tension of the increasing thread relative to the tension of the ear part, the more difficult it is to hang the ear, so it is more preferable to adjust the tension of the increasing thread relative to the tension of the ear part to be 1.40 times or less.

[0055] The method for adjusting the additional yarn tension to be 1.20 times or more than the ear warp tension is not particularly limited. For example, the additional yarn is supplied one by one from a paper tube, a bobbin, etc., and the tension is controlled by a tenser such as a spring washer, or a beam for supplying the additional yarn is prepared and the tension is controlled respectively, etc. can be adjusted.

[0056] (Scouring, heat setting) The woven fabric is then appropriately processed such as scouring and heat setting.

[0057] The scouring temperature in the scouring process is preferably 20°C or higher, more preferably 25°C or higher. Also, the scouring temperature is preferably 80°C or lower, more preferably 70°C or lower. When the scouring temperature is 20°C or higher, the residual strain of the fabric is removed, the filaments in the multifilament yarn move more easily, and the multifilament yarn can spread flat with respect to the fabric. Therefore, the dimensional stability of the fabric can be improved. Also, when the scouring temperature is 80°C or lower, significant shrinkage of the multifilament is suppressed. As a result, the dimensional stability of the fabric can be improved.

[0058] The heat setting temperature in the heat setting is preferably a temperature that can remove the strain remaining in the fabric after weaving and suppress significant shrinkage of the multifilament yarn, similar to scouring. Specifically, the heat setting temperature is preferably 110°C or higher, more preferably 120°C or higher. Also, the heat setting temperature is preferably 190°C or lower. When the heat setting temperature is within the above range, the resulting fabric can have improved dimensional stability.

[0059] In the weaving process, when the tension of the ear warp is excessively higher than that of the ground warp, ear hanging occurs in the ear part. Then, the operating efficiency of the manufacturing equipment decreases. Also, at the location where pin detachment occurs, various physical properties may change. On the other hand, since the relationship between the tension of the ear warp and the tension of the ground warp of the airbag fabric of the present embodiment is controlled, it has the effect of being less likely to cause pin detachment in the heat setting process. Therefore, it has high process passing performance and can improve the yield of the airbag fabric.

[0060] The fabric that has undergone the above processes may be appropriately coated with a resin or an elastomer. The airbag fabric of the present invention can be imparted with airtightness by applying a coating. When applying a coating, the coating amount is preferably about 5 to 35 g / m 2 It is preferably in the range. As the resin or elastomer, those having heat resistance, cold resistance, and flame retardancy are preferred. As the resin or elastomer, for example, silicone resin, polyamide-based resin, polyurethane resin, fluororesin, etc. are preferably used.

[0061] The fabric that has undergone the above processes may be appropriately subjected to ear cutting. By performing ear cutting, it becomes easier to adjust the position during cutting. As the part of the fabric discarded by ear cutting, cut the warp from the ear end of the fabric to about 25 mm from the ear end where the pin hole is formed by the entangled yarn, increased yarn, ear tightening yarn, and heat setting. By cutting the part not used as the fabric of the ear part, the number of laminatable sheets in the cutting process can increase, and the cutting efficiency can be improved.

Example

[0062] Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples. In the following examples, each characteristic value was calculated by the following method.

[0063] <Calculation method of characteristic value> (Total fineness) The total fineness was calculated by measuring the linear density under a specified load of 0.045 cN / dtex in accordance with Method A of JIS L1013 (2010) 8.3.1.

[0064] (Number of filaments) The number of filaments was calculated based on the method of JIS L1013 (1999) 8.4.

[0065] (Weave density) The weave density of each of the warp and weft was calculated based on JIS L1096 (2010) 8.6.1. Specifically, the sample was placed on a flat table, and the number of warp and weft threads in a 2.54 cm section was counted at five different locations, excluding unnatural wrinkles and tensions, and the average value of each was calculated.

[0066] (Cover factor CF) The cover factor was calculated as CF = (D1 × 0.9) 1 / 2 × N1 + (D2 × 0.9) 1 / 2 × N2.

[0067] Here, let the total fineness of the warp be D1 (dtex), the warp density be N1 (threads / 2.54 cm), the total fineness of the weft be D2 (dtex), and the weft density be N2 (threads / 2.54 cm).

[0068] (Crimp ratio) The crimp ratio was measured based on Method B of JIS L1096 (2010) 8.7.

[0069] The sample was placed on a flat table, and marks were made at intervals of 20 cm from one end of the fabric, excluding unnatural wrinkles and tensions. The threads between these marks were unraveled to obtain the decomposed threads, and the lengths when stretched straight under the initial load specified in JIS L1013 (2010) 5.1 were measured respectively, and the average value was calculated to obtain the change in length. The CV value was calculated by dividing the standard deviation of the data collected every 20 cm from one end of the fabric by the average value and multiplying by 100.

[0070] (Air permeability at 20 kPa differential pressure) The 20 kPa differential pressure air permeability was measured every 20 cm in the weft direction from one end of the fabric piece in accordance with Method A of JIS L1096 (1999) 8.27.1. The fabric was attached to one end of a cylinder with a diameter of 100 mm and fixed so that there was no air leakage from the attachment point. The test differential pressure was adjusted to 20 kPa using a regulator, and the amount of air passing through the fabric was measured with a flow meter. The CV value was calculated by dividing the standard deviation of the data collected every 20 cm by the average value and multiplying by 100.

[0071] (Evaluation of the flare height of the fabric) The woven fabric was cut to a length of 1 m and spread out on a flat table, and the height of the most raised part of the ear was measured in 1 mm increments (amounts less than 1 mm were rounded off), and the average value of both ears was calculated. The evaluation was judged based on the height of the flare, with less than 8 mm being "A", 8 mm or more and less than 10 mm being "B", 10 mm or more and less than 12 mm being "C", and 12 mm or more being "D", and "B" and below were considered qualified. Also, fabrics with ear collapse were designated as "-".

[0072] (Evaluation of process passing performance) For the woven fabric that had been woven, scoured, and heat-set, and then wound up to a length of 1000 m, the number of wrinkles 50 cm or longer was counted. And the number of wrinkles was evaluated according to the following criteria. A: 0 to 1, B: 2 to 4, C: 5 to 9, D: 10 or more.

[0073] However, in the above evaluation, when the fabric came off the pin tenter in the heat-setting process, that is, when pin detachment occurred, it was evaluated as "not acceptable".

[0074] <Example 1> (Warp, weft) As the warp and weft, nylon 6,6 was used, which had a circular cross-sectional shape, was composed of 72 filaments of single fiber with a single fiber fineness of 6.52 dtex, had a total fineness of 470 dtex, a tensile strength of 8.4 cN / dtex, an elongation of 23.5%, and untwisted synthetic fiber filaments were prepared.

[0075] Weaving Using the above yarns as warp and weft yarns for the ground part, a water jet loom equipped with a full-width template was used to weave a plain fabric with a warp density of 55 threads / 2.54 cm, a weft density of 55 threads / 2.54 cm, and a fabric width of 210 cm. At that time, the warp tension was adjusted to 0.40 cN / dtex.

[0076] At that time, winding yarns and increasing yarns were used for both ears of the fabric. As the winding yarns, 22 detex nylon 6,6 monofilaments were used, and two were supplied to each of the two ears from a planetary device. For the increasing yarns, 22 dtex nylon 6,6 monofilaments similar to the winding yarns were used, and eight were supplied to each of the two ears from a bobbin at 0.41 cN / dtex. As the warp yarns constituting the fabric ears, the same yarns as those of the fabric ground part were used, and 24 were used for each of the two ears. In order to manage the tension of the warp yarns during supply, one beam wound with 24 warp yarns constituting the fabric ears was prepared for each of the two ears, and the tension was adjusted by adjusting the supply speed of the warp yarns respectively. The beam for supplying the warp yarns of the ears was prepared by adjusting to 0.34 cN / dtex, inserted 24 in order from the ear end side, and woven.

[0077] Scouring and Heat Setting Next, the obtained fabric was scoured at 65 °C with an open soaper type scouring machine, rinsed with hot water at 40 °C, and dried at 120 °C. Furthermore, using a pin tenter dryer, the width expansion rate was set so as to have the same width as the width of the fabric after drying, and the fabric was heat set at 180 °C for 60 seconds under dimensional control with an overfeed rate of 2%.

[0078] Example 2 Warp and Weft As the warp and weft yarns, the same synthetic fiber filaments as in Example 1 were prepared.

[0079] Weaving Next, weaving was carried out under the same conditions as in Example 1 except that the tension of the warp yarns of the ears was changed to 0.46 cN / dtex and the tension of the increasing yarns was changed to 0.60 cN / dtex.

[0080] (Scouring and heat setting) Next, scouring and heat setting were carried out in the same manner as in Example 1.

[0081] <Comparative Example 1> (Warp, weft) As the warp and weft, the same synthetic fiber filaments as in Example 1 were prepared.

[0082] (Weaving) Next, an airbag fabric was produced in the same manner as in Example 1, except that the tension of the warp in the ear part was changed to 0.30 cN / dtex and the tension of the filling yarn was changed to 0.40 cN / dtex.

[0083] (Scouring and heat setting) Next, scouring and heat setting were carried out in the same manner as in Example 1.

[0084] <Comparative Example 2> (Warp, weft) As the warp and weft, the same synthetic fiber filaments as in Example 1 were prepared.

[0085] (Weaving) Next, an airbag fabric was produced in the same manner as in Example 1, except that the tension of the warp in the ear part was changed to 0.52 cN / dtex and the tension of the filling yarn was changed to 0.70 cN / dtex.

[0086] (Scouring and heat setting) Next, scouring and heat setting were carried out in the same manner as in Example 1.

[0087] The crimp ratio of the warp in the obtained fabric ear part was 12%, and the differential pressure air permeability at 20 kPa was 1.02 L / cm 2 / min.

[0088] <Comparative Example 3> (Warp, weft) As the warp and weft, the same synthetic fiber filaments as in Example 1 were prepared.

[0089] Weaving An airbag fabric was produced in the same manner as in Example 1, except that the tension of the warp yarns in the ear part was changed to 0.52 cN / dtex and the tension of the filling yarns was changed to 0.55 cN / dtex.

[0090] Scouring and Heat Setting Subsequently, scouring and heat setting were carried out in the same manner as in Example 1.

[0091] The crimp ratio of the warp yarns in the obtained fabric ear part was 12%, and the air permeability at a differential pressure of 20 kPa was 1.05 L / cm 2 / min.

[0092] <Example 3> Warp Yarns and Filling Yarns As the warp yarns and filling yarns, synthetic fiber filaments made of nylon 6,6, having a circular cross-sectional shape, composed of 136 filaments of single fiber fineness 2.57 dtex, with a total fineness of 350 dtex, a tensile strength of 8.4 cN / dtex, an elongation of 23.5%, and no twist were prepared.

[0093] Weaving Using the above yarns as the ground yarns for the warp and filling, a plain weave fabric with a warp density of 60 yarns / 2.54 cm, a filling density of 60 yarns / 2.54 cm, and a fabric width of 200 cm was woven using a water jet loom equipped with a full-width template. At that time, the warp tension was adjusted to 0.40 cN / dtex.

[0094] At that time, winding yarns and additional yarns were used for both ear parts of the fabric. As the winding yarns, 22 detex nylon 6,6 monofilaments were used, and two pieces each were supplied to both ear parts from a planetary device. As the additional yarns, 22 dtex nylon 6,6 monofilaments similar to the winding yarns were used, and eight pieces each were supplied from bobbins to both ear parts with a tension of 0.44 cN / dtex. As the warp yarns constituting the fabric ear parts, the same yarns as those of the fabric ground part were used, and 30 pieces each were used for both ear parts. In order to manage the tension during supply, for the warp yarns constituting the fabric ear parts, one beam wound with 30 warp yarns was prepared for each of the two ear parts, and the tension was adjusted by adjusting the supply speed of the warp yarns respectively. The beams for supplying the warp yarns of the ear parts were prepared with the tension adjusted to 0.33 cN / dtex, and 30 pieces were inserted in order from the ear end part side and woven.

[0095] (Scouring and heat setting) Next, the obtained fabric was scoured at 65 °C using an open soaper type scouring machine, rinsed with hot water at 40 °C, and dried at 120 °C. Further, using a pin tenter dryer, the width expansion rate was set so as to have the same width as the width of the fabric after drying, and the fabric was heat set at 180 °C for 60 seconds under dimensional control with an overfeed rate of 2%.

[0096] (Example 4) (Warp and weft) As the warp and weft, synthetic fiber filaments similar to those in Example 3 were prepared.

[0097] (Weaving) Next, weaving was carried out in the same manner as in Example 3 except that the tension of the warp yarns of the ear part was changed to 0.45 N / dtex and the tension of the additional yarns was changed to 0.56 cN / dtex.

[0098] (Scouring and heat setting) Next, scouring and heat setting were carried out in the same manner as in Example 3.

[0099] (Comparative Example 4) (Warp and weft) As the warp and weft, synthetic fiber filaments similar to those in Example 3 were prepared.

[0100] (Weaving) Next, weaving was performed in the same manner as in Example 3, except that the tension of the warp yarn in the ear part was changed to 0.30 cN / dtex and the tension of the filling yarn was changed to 0.38 cN / dtex.

[0101] (Scouring and Heat Setting) Next, scouring and heat setting were performed in the same manner as in Example 3.

[0102] <Comparative Example 5> (Warp, Weft) The same synthetic fiber filaments as in Example 3 were prepared as the warp and weft.

[0103] (Weaving) Next, weaving was performed in the same manner as in Example 3, except that the tension of the warp yarn in the ear part was changed to 0.56 cN / dtex and the tension of the filling yarn was changed to 0.80 cN / dtex.

[0104] (Scouring and Heat Setting) Next, scouring and heat setting were performed in the same manner as in Example 3.

[0105] <Example 5> (Warp, Weft) As the warp and weft, synthetic fiber filaments made of nylon 6,6, having a circular cross-sectional shape, composed of 136 filaments of a single fiber fineness of 2.57 dtex, having a total fineness of 470 dtex, a tensile strength of 8.4 cN / dtex, an elongation of 23.5%, and being untwisted were prepared.

[0106] (Weaving) Using the above yarns as the warp and weft of the ground part, a plain woven fabric with a warp density of 53 threads / 2.54 cm, a weft density of 53 threads / 2.54 cm, and a fabric width of 200 cm was woven using a water jet loom equipped with a full-width template. At that time, the warp tension was adjusted to 0.40 cN / dtex.

[0107] At that time, winding yarns and increasing yarns were used for both ear parts of the fabric. As the winding yarns, 22 detex nylon 6,6 monofilaments were used, and two pieces were supplied to each of the two ear parts from the planetary device. For the increasing yarns, 22 dtex nylon 6,6 monofilaments similar to the winding yarns were used, and eight pieces were supplied to each of the two ear parts from the bobbin at a tension of 0.50 cN / dtex. As the warp yarns constituting the fabric ear parts, the same yarns as those of the fabric ground part were used, and 24 pieces were used for each of the two ear parts. In order to control the tension during supply, for the warp yarns constituting the fabric ear parts, one beam wound with 24 warp yarns was prepared for each of the two ear parts, and the tension was adjusted by adjusting the supply speed of the warp yarns respectively. The beams for supplying the warp yarns of the ear parts were prepared with the tension adjusted to 0.41 cN / dtex, and 24 pieces were inserted in order from the ear end part side and woven.

[0108] (Scouring and heat setting) Next, the obtained fabric was scoured at 65 °C with an open soaper type scouring machine, rinsed with hot water at 40 °C, and dried at 120 °C. Further, using a pin tenter dryer, the width expansion rate was set so as to have the same width as the width of the fabric after drying, and the fabric was heat set at 180 °C for 60 seconds under dimensional control with an overfeed rate of 2%.

[0109] (Comparative Example 6) (Warp yarns, weft yarns) As the warp yarns and weft yarns, the same synthetic fiber filaments as in Example 5 were prepared.

[0110] (Weaving) Next, weaving was carried out in the same manner as in Example 5 except that the tension of the warp yarns of the ear part was changed to 0.31 cN / dtex and the tension of the increasing yarns was changed to 0.39 cN / dtex.

[0111] (Scouring and heat setting) Next, scouring and heat setting were carried out in the same manner as in Example 5.

[0112] (Example 6) (Warp yarns, weft yarns) As the warp and weft threads, single fibers made of nylon 6,6, having a circular cross-sectional shape, composed of 136 filaments of single fiber with a single fiber fineness of 2.57 dtex, with a total fineness of 470 dtex, a tensile strength of 8.4 cN / dtex, and an elongation of 23.5%, were prepared as non-twisted synthetic fiber filaments.

[0113] (Weaving) Using the above-mentioned threads as the ground warp and weft, a plain weave fabric with a warp density of 50 threads / 2.54 cm, a weft density of 50 threads / 2.54 cm, and a fabric width of 200 cm was woven using a water jet loom equipped with a full-width template. At that time, the warp tension was adjusted to 0.40 cN / dtex.

[0114] At that time, winding threads and additional threads were used for both ears of the fabric. As the winding threads, 22 detex nylon 6,6 monofilaments were used, and two threads were supplied to each of the two ears from a planetary device. The additional threads used were the same 22 dtex nylon 6,6 monofilaments as the winding threads, and eight threads were supplied to each of the two ears from a bobbin with a tension of 0.59 cN / dtex. As the warp threads constituting the fabric ears, the same threads as those of the fabric ground part were used, and 24 threads were used for each of the two ears. In order to manage the tension during supply, a beam wound with 24 warp threads constituting the fabric ears was prepared for each of the two ears, and the tension was adjusted by adjusting the supply speed of the warp threads respectively. The beam for supplying the warp threads of the ears was prepared with an adjusted tension of 0.47 cN / dtex, and 24 threads were inserted in order from the ear end side and woven.

[0115] (Scouring and Heat Setting) Next, scouring and heat setting were carried out in the same manner as in Example 3.

[0116] <Comparative Example 7> (Warp, Weft) As the warp and weft threads, the same synthetic fiber filaments as in Example 6 were prepared.

[0117] (Weaving) Next, weaving was carried out in the same manner as in Example 6, except that the tension of the warp yarns in the ear part was changed to 0.24 cN / dtex and the tension of the filling yarns was changed to 0.30 cN / dtex.

[0118] (Scouring and Heat Setting) Next, scouring and heat setting were carried out in the same manner as in Example 6.

[0119] <Example 7> (Warp Yarns, Weft Yarns) As the warp and weft yarns, synthetic fiber filaments made of nylon 6,6, having a circular cross-sectional shape, composed of 136 filaments of single fiber fineness of 2.57 dtex, with a total fineness of 470 dtex, a tensile strength of 8.4 cN / dtex, an elongation of 23.5%, and non-twisted were prepared.

[0120] (Weaving) Using the above yarns as the ground yarns for the warp and weft, a plain weave fabric with a warp density of 50 threads / 2.54 cm, a weft density of 50 threads / 2.54 cm, and a fabric width of 200 cm was woven using a water jet loom equipped with a full-width template. At that time, the warp tension was adjusted to 0.40 cN / dtex.

[0121] At that time, wrap yarns and filling yarns were used for both ears of the fabric. As the wrap yarns, 22 detex nylon 66 monofilaments were used, and two were supplied to each ear from a planetary device. Also, as the filling yarns, 22 dtex nylon 66 monofilaments similar to the wrap yarns were used, and eight were supplied to each ear from a bobbin at a tension of 0.50 cN / dtex. And the warp yarns in the ear part were supplied from the same beam as the warp ground part. When the tension of the warp yarns in the ear part was measured after the tension became stable, it was 0.35 cN / dtex.

[0122] (Scouring and Heat Setting) Next, scouring and heat setting were carried out in the same manner as in Example 3. <Comparative Example 8> (Warp Yarns, Weft Yarns) As the warp and weft yarns, synthetic fiber filaments similar to those in Example 6 were prepared.

[0123] Weaving Next, weaving was carried out in the same manner as in Example 7, except that the warp tension of the ear part was changed to 0.28 cN / dtex and the tension of the additional yarn was changed to 0.30 cN / dtex.

[0124] Scouring and heat setting Next, scouring and heat setting were carried out in the same manner as in Example 6.

[0125] [Table 1]

Claims

1. An airbag fabric having a ground part and ear parts, and including thickened yarns as the warp yarns of the ear parts, wherein the thickened yarns are monofilaments with a fineness of 33 dtex or less, each ear part contains 4 or more of the thickened yarns, and the ratio (B / A) of the average warp crimp rate A at the center of the fabric to the average warp crimp rate B at a position 50 mm from the end of the fabric is 0.90 or more and 1.10 or less. An airbag fabric.

2. The airbag fabric according to Claim 1, wherein the CV value of the warp crimp rate per 20 cm in the weft direction is 3.0% or less.

3. The airbag fabric according to Claim 1 or 2, wherein the CV value of the air permeability at a differential pressure of 20 kPa according to JIS L1096 (1996) is 10% or less.

4. The airbag fabric according to Claim 1 or 2, wherein the total fineness of the multifilaments constituting the fabric is 200 to 470 dtex.

5. The airbag fabric according to Claim 1 or 2, wherein the cover factor of the fabric is 2000 to 2500.

6. A method for manufacturing an airbag fabric according to Claim 1 or 2, characterized in that in the weaving process, 4 or more thickened yarns made of monofilaments with a fineness of 33 dtex or less are used at the ends of the fabric, and the tension of the thickened yarns with respect to the tension of the ear parts is adjusted to be 1.20 times or more and 1.50 times or less.

7. The method for manufacturing an airbag fabric according to Claim 6, wherein in the weaving process, the warp tension of the ear parts is adjusted to be in the range of 0.80 to 1.20 times the warp tension of the ground part.

8. An airbag in which the airbag fabric according to Claim 1 or 2 is sewn.

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