JP5365272B2 - Fabric for airbag and method for producing fabric for airbag - Google Patents

Description

  The present invention relates to an airbag fabric and a method for manufacturing the airbag fabric.

  In recent years, with the improvement of traffic safety awareness, the effectiveness of various airbags has been recognized as a result of the development of various airbags in order to ensure the safety of passengers in the event of a car accident. It is out.

  The airbag is inflated and deployed in the vehicle in a very short time after the vehicle has collided, thereby receiving the occupant moving by the reaction of the collision and absorbing the impact to protect the occupant. In view of this action, it is required that the amount of ventilation of the fabric constituting the bag is small. Also, in recent years, air bags have been inflated and deployed for the purpose of further improving passenger restraint, and in order to keep the internal pressure of the bag above a certain level when catching an occupant, gas leaks from the fabric when the gas hits the fabric. The demand for prevention is also increasing.

  Conventionally, as a means for reducing the air flow rate of a fabric, a coated fabric in which a resin is applied to an airbag fabric or a film is attached has been proposed.

  However, when a resin is applied or a film is applied, the thickness of the fabric increases and the compactness at the time of storage deteriorates, which is inappropriate as a fabric for an airbag. Moreover, there is a problem that the manufacturing cost increases due to the increase in the resin coating process and the film attaching process.

In order to solve these problems, non-coated fabrics have recently been proposed that reduce the air flow rate of fabrics by weaving synthetic filament yarns such as polyamide fibers and polyester fibers at high density without applying resin processing. For example, as means for realizing low air permeability, there is disclosed means for using a woven fabric having a symmetrical woven fabric structure using synthetic filament yarn having a fineness of 300 to 400 dtex (see Patent Document 1). According to this means, an air flow rate of 10 L / dm ² · min or less is achieved at a test differential pressure of 500 Pa.

Further, for example, a means is disclosed in which a non-coated cloth that has been treated in a water bath within a temperature range of 60 to 140 ° C. is applied to a woven fabric made of polyamide filament yarn having a hot air shrinkage of 6 to 15% (Patent Document). 2). This means also achieves an air flow rate of less than 10 L / dm ² · min at a test differential pressure of 500 Pa.

Further, an airbag base fabric is disclosed in which the cross-sectional shape of a single fiber of a multifilament yarn is flattened to improve low air permeability and bag storage compactness. (See Patent Documents 3 and 4). According to this means, an air flow rate of 0.2 cc / cm ² / sec or less at a test differential pressure of 125 Pa and 0.7 L / cm ² / min or less at a test differential pressure of 19.6 kPa is achieved.

  However, the low airflow achieved by these means is a static airflow characteristic in a state where the differential pressure is kept constant, but the actual fabric expansion / ventilation behavior when the airbag functions. Is determined by the high-pressure gas that is applied instantaneously or the contact of the occupant, or is greatly influenced, and it is considered that there are characteristics that cannot be fully evaluated by static ventilation characteristics such as internal pressure retention. The internal pressure retention is important for protecting the occupant by absorbing the collision energy even after the occupant contacts the airbag.

  Therefore, ASTM D6476 defines an evaluation method for dynamic ventilation characteristics. However, the above means are still insufficient as dynamic ventilation characteristics.

JP-A-3-137245 (Claim 1) JP-A-4-281062 (Claims 1 and 2, paragraph 0026) JP 2003-171841 (Claim 3) JP-A-2005-281933 (Claim 4)

ASTM D6476

  An object of the present invention is to provide an airbag fabric excellent in dynamic low ventilation characteristics and, in turn, excellent in internal pressure retention characteristics.

  That is, the present invention is an airbag fabric made of synthetic fiber multifilament yarn, having an average dynamic air permeability (ADAP) measured based on ASTM D6476 of 500 mm / s or less, and A measured air permeability curve exponent (Exponent) is 1.5 or less.

  Further, the present invention is a method for producing the airbag fabric of the present invention, wherein the weaving is carried out by adjusting the warp yarn tension to 0.11 to 0.34 cN / main / dtex in weaving, and scouring at 20 to 65 ° C. And it is a manufacturing method of the textile fabric for airbags characterized by carrying out heat setting at 80-150 degreeC.

  According to the present invention, it is possible to obtain an airbag fabric that is excellent in dynamic low air permeability characteristics and, in turn, excellent in internal pressure retention characteristics.

  The airbag fabric of the present invention is made of synthetic fiber multifilament yarn. As the synthetic fiber constituting the synthetic fiber multifilament yarn, for example, polyamide fiber, polyester fiber, aramid fiber, rayon fiber, polysulfone fiber, ultrahigh molecular weight polyethylene fiber and the like can be used. Of these, polyamide fibers and polyester fibers excellent in mass productivity and economy are preferable.

  Examples of polyamide fibers include nylon 6, nylon 66, nylon 12, nylon 46, copolymer polyamide of nylon 6 and nylon 66, and copolymer obtained by copolymerizing nylon 6 with polyalkylene glycol, dicarboxylic acid, amine, and the like. Mention may be made of fibers made of polyamide or the like. Nylon 6 fiber and nylon 66 fiber are particularly excellent in impact resistance and are preferable.

  Examples of the polyester fiber include fibers made of polyethylene terephthalate, polybutylene terephthalate, and the like. It may be a fiber made of a copolymerized polyester obtained by copolymerizing polyethylene terephthalate or polybutylene terephthalate with an aliphatic dicarboxylic acid such as isophthalic acid, 5-sodium sulfoisophthalic acid or adipic acid as an acid component.

  Synthetic fibers also have thermal stabilizers, antioxidants, light stabilizers, smoothing agents, antistatic agents, plasticizers, thickeners to improve productivity and properties in the spinning / drawing process and processing process. Additives such as additives, pigments, and flame retardants may be included.

  Moreover, as a cross-sectional shape of the single fiber of the synthetic fiber, a flat cross section may be used in addition to the round cross section. Such a flat cross-sectional shape may be a geometrically true elliptical shape, for example, a rectangular shape, a rhombus shape, or a saddle shape, or a left-right symmetric shape or a left-right asymmetric shape. Moreover, the thing of the shape which combined these may be sufficient. Furthermore, with the above as a basic shape, there may be a protrusion, a dent, or a partially hollow portion.

  The single fiber fineness of the synthetic fiber filament constituting the synthetic fiber filament yarn is preferably 2 dtex or less. By setting it to 2 dtex or less, an airbag fabric excellent in dynamic low ventilation characteristics described later can be obtained. The mechanism is described next.

  That is, if the single fiber fineness is 2 dtex or less, and the synthetic fiber multifilament yarn is composed of a larger number of filaments than the conventional one, not only the fiber filling effect is further improved and low air permeability is obtained, but also the woven fabric. The single filaments in the multifilament yarn are easy to move when the compressed gas hits them, and the multifilament yarn spreads flat against the fabric surface, and only fills the fine gaps that cause ventilation in the multifilament yarn. In addition, the voids in the mesh portion of the fabric can be effectively sealed. Moreover, since the effect which reduces the rigidity of a synthetic fiber multifilament thread | yarn is acquired by making single fiber fineness into 2 dtex or less, the stowability of an airbag can also be improved.

  Moreover, it is preferable to set it as 1 dtex or more as a lower limit of the single fiber fineness of a synthetic fiber filament. By doing so, it is possible to prevent the synthetic fiber filament from melting due to the heat of the high-temperature gas released from the inflator.

  The tensile strength of the single fiber of the synthetic fiber filament is preferably 8.0 to 9.0 cN / dtex for both the warp yarn and the weft yarn in order to satisfy the mechanical properties required for the airbag fabric and from the viewpoint of the yarn production operation. More preferably, it is 8.3-8.7 cN / dtex.

The total fineness of the synthetic fiber filament yarn is preferably 100 to 700 dtex, more preferably 200 to 500 dtex, still more preferably 300 to 400 dtex. By setting it as 100 dtex or more, the above sealing effects can be obtained efficiently and the strength of the fabric can be maintained. Moreover, the compactness and flexibility at the time of accommodation can be maintained by setting it as 700 dtex or less. Further, in order to obtain a multifilament yarn having a single fiber fineness of 1 to 2 dtex and a total filament size exceeding 700 dtex, the number of single fibers must be increased. There is a need to form a fiber yarn formed by combining three yarns (multifilament yarns having a small total fineness), which impairs productivity and increases costs.
Regarding the fibers of airbag fabrics, it has been studied for many years to reduce both the total fineness and the single fiber fineness. However, as in the present invention, the single fiber fineness of 2 dtex or less within the range of the total fineness of 100 to 700 dtex. There is no example in which a polyamide fiber having a fiber is actually disclosed, and there is naturally no example disclosed in the characteristics provided when a fabric for an airbag is formed using such a polyamide fiber. This is because, in the conventional examination, the improvement in the characteristics of the airbag fabric tends to be saturated when the single fiber fineness is reduced to about 3 to 4 dtex, and in addition, the number of single fibers is 100 or more and 2 dtex or less. This is because it was extremely difficult to stably produce industrial polyamide fibers having fineness by the direct spinning drawing method. The inventors have obtained a method for obtaining a polyamide fiber multifilament yarn having a single fiber number of 100 or more and 2 dtex or less by the method described later, and the characteristics of an airbag fabric composed of the polyamide fiber multifilament yarn. We studied diligently. As a result, the dynamic low air permeability described later is improved by setting the single fiber fineness to 2 dtex or less as compared with the case where the polyamide fiber having the same total fineness but different only in the single fiber fineness is used as the airbag fabric by the same method. It has been investigated. In addition, it is difficult to obtain a polyamide fiber suitable for an airbag having a single fiber fineness of less than 1 dtex even if the method described in this specification is used.

  The cover factor (CF) of the fabric is preferably 1800-2300. By setting the cover factor to 1800 or more, low air permeability can be obtained. Moreover, compact storage property can be improved by setting it as 2300 or less.

Here, the cover factor (CF) of the woven fabric is a value calculated from the total fineness and woven density of the yarn used for the warp yarn or the weft yarn. The warp yarn total fineness is Dw (dtex), and the weft yarn total fineness. Is Df (dtex), the weft density of the warp yarn is Nw (lines / 2.54 cm), and the weave density of the weft yarn is Nf (lines / 2.54 cm).
CF = (Dw × 0.9) ^1/2 × Nw + (Df × 0.9) ^1/2 × Nf.

  In the airbag fabric of the present invention, it is important that the average dynamic air permeability (ADAP) measured based on ASTM D6476 is 500 mm / s or less, preferably 400 mm / s or less, more preferably 300 mm / s. s or less. By doing so, when the airbag is inflated and deployed to receive the occupant, gas leakage from the fabric can be suppressed as much as possible, and the internal pressure of the airbag can be maintained. In this measurement, the compressed air filled in the test head is instantaneously released and applied to the fabric sample, and the air permeability (dynamic air permeability) according to the changing pressure is measured, and the upper limit after the maximum pressure is reached. The average air flow rate of dynamic air permeability within the range of pressure (UPPER LIMIT) to lower limit pressure (LOWER LIMIT) is calculated. This method of measuring the air leakage after the maximum pressure is achieved represents the internal pressure retention after the airbag is deployed until the occupant is restrained and the occupant is finished, and the air permeability under a certain pressure is measured. The static air permeability is completely different. The measurement conditions of the average dynamic air permeability (ADAP) of the present invention are such that the pressure of compressed air is adjusted so that the maximum pressure is 100 ± 5 kPa, the lower limit pressure for calculating the average dynamic air permeability is 30 kPa, and the upper limit pressure is It was set to 70 kPa and the area of the internal pressure of the air bag during actual passenger restraint.

  In the airbag fabric of the present invention, it is important that the dynamic air permeability curve index (Exponent) measured based on ASTM D6476 is 1.5 or less, preferably 1.4 or less, more preferably Is 1.3 or less. The dynamic air permeability curve index (Exponent) is a curve index E obtained from the pressure-dynamic air permeability curve obtained by the measurement of the above average dynamic air permeability, and is measured by an air permeability tester FX3350 exclusively for airbags manufactured by TEXTEST. Calculated. The inventors of the present invention have intensively studied the relationship between the dynamic air permeability curve index and the bag internal pressure retention when the occupant is received after the airbag is inflated and deployed, and the dynamic air permeability curve index is 1.5 or less. It was found that this is important for maintaining the internal pressure of the bag.

  The dynamic air permeability curve index will be described in detail. When the dynamic air permeability curve index is 1.0, a constant air permeability is exhibited regardless of changes in the bag internal pressure. When the dynamic air permeability curve index is greater than 1.0, it indicates that the air permeability increases with an increase in the bag internal pressure. When the dynamic air permeability curve index is smaller than 1.0, it indicates that the air permeability decreases as the bag internal pressure increases. In general, the smaller the average dynamic air permeability, the greater the dynamic air permeability curve index. That is, if there is a flow path through which air can pass, this means that the flow path expands and the air permeability increases as the bag internal pressure increases. When deploying an airbag, if the occupant hits an inflated airbag, the pressure inside the bag increases, and the increase in pressure causes an increase in air permeability. Inflator gas loss is greater than

  The air bag fabric feature of the present invention is that the dynamic air permeability curve index is small despite the small average dynamic air permeability.

  Next, the manufacturing method of the polyamide multifilament yarn which is the preferable form which comprises the textile fabric for airbags of this invention, and the method of manufacturing the textile fabric for airbags are demonstrated.

  Polyamide multifilament yarn is produced by the following method based on melt spinning.

First, the above-described polyamide chip is supplied to an extruder-type spinning machine, and is distributed to a spinneret by a lightweight pump, and melt-spun at 290 to 300 ° C. At this time, the hole spec of the spinneret is preferably designed to have a back pressure of at least 60 kg / cm ² or more in order to reduce the variation in single fiber fineness and suppress the occurrence of fuzz during weaving, and 80 to 120 kg. / Cm ² is more preferable. Further, the discharge holes are arranged on concentric circles, and the number of rows is preferably 2 to 8 rows, more preferably 3 to 6 rows. If the number of rows is too small, the distance between single fibers will be too small, the single fibers will collide with each other during spinning, and if bad, they will be fused, and if too large, the physical properties between single fibers due to cooling spots will increase, which is preferable. Absent. Moreover, although the diameter when connecting each discharge hole arranged in the outermost periphery as a concentric circle is made smaller than the internal diameter of a slow cooling cylinder (heating cylinder) or an annular cooling device, it is preferably 8 to 25 mm, more preferably 10 to 20 mm. Just make it smaller. The slow cooling cylinder is installed in order to prevent a decrease in the strength and elongation by slow cooling the yarn immediately after melt spinning. Generally, the in-cylinder ambient temperature before cooling is extruded in a molten state. Heated to raise the crystallization temperature of the warp yarn, or kept warm using a heat insulating material. Therefore, it is also called a heating cylinder or a heat insulating cylinder. If the position of the outermost hole is too close to the slow cooling tube (heating tube) or the annular cooling device, the yarn before solidification easily comes into contact with the device and spinning becomes unstable, and if it is too far, Insufficient cooling makes it difficult to obtain a polyamide multifilament yarn having high strength and high elongation.

It is preferable to apply water vapor to the spun yarn discharged from the die. In polyamide fiber melt spinning, it is common to retain an inert gas, particularly water vapor, immediately below the die, but it has been disclosed that the mechanical properties of industrial polyamide fibers are particularly changed by water vapor. Absent. Surprisingly, in the production of high-strength polyamide multifilament yarns with small single fiber fineness using the annular cooling device of the present invention, water vapor has the effect of improving both strength and elongation and further reducing fineness spots. I found out. The water vapor blowing hole may be a known one having a diameter of 0.5 to 5 mm and a length of about 1 to 10 mm. If the amount of water vapor is excessively increased, the strength and elongation will be reduced, the fineness will be deteriorated, and the fluff and thread breakage will be increased. Therefore, the blowing pressure is preferably 100 to 600 Pa, more preferably 200 to 400 Pa. . The blowing pressure is a static pressure value, and the static pressure of the steam flowing into the hole may be measured with a static pressure measuring device.
The yarn to which water vapor has been applied passes through a cylindrical slow cooling cylinder and a cylindrical annular cooling device in order to complete cooling and solidification. It is preferable that the inner diameter of the slow cooling cylinder is the same as the inner diameter of the annular cooling device to prevent air flow disturbance at the contact point between the slow cooling cylinder and the annular cooling device in the cylinder, preferably 30 to 150 mm, more preferably 50. It is preferable to heat the tube so that the atmospheric temperature in the cylinder is 250 to 350 ° C. with a length of ˜100 mm, more preferably 50 to 80 mm, and then cool using an annular cooling device. By using a slow cooling cylinder, it is possible to obtain a polyamide fiber having excellent toughness by increasing the heat retaining property of the base and making the deformation of the yarn gentle, but the length of the slow cooling cylinder is in the above range. And the thickness spot of the longitudinal direction of a polyamide fiber becomes more uniform. If the single fiber fineness is less than 1.5 dtex, install an annular cooling device without using a slow cooling cylinder, and start cooling the spun yarn faster, thereby causing unevenness in the longitudinal direction of the yarn. In this case, in order to obtain a polyamide multifilament yarn having high strength and high elongation by keeping the base surface warm, a constant length within 100 mm from the top of the annular cooling device is used. It is preferable to blow out hot air at 100 to 250 ° C.

  In cooling the yarn by the annular cooling device, it is preferable to use cooling air of 10 to 50 ° C. so that the polyamide can be sufficiently cooled to the glass transition point. A basic configuration of the annular cooling device may be used. For example, a cylindrical body is constituted by a porous member having a large number of capillary holes, and the cooling air sent into the cooling cylinder is blown out while being rectified from the cooling air blowing portion in the yarn direction. That's fine. In order to adjust the cooling air speed, for example, it is preferable to install a porous member such as a punched plate or mesh in the air introduction portion of the cooling cylinder element. In order to obtain a polyamide multifilament yarn having a single fiber fineness with high strength and high elongation constituting the airbag fabric of the present invention, it is preferable to have the following characteristics.

  The cooling air is blown from the outer peripheral side of the discharge hole group to the center side. By adopting this configuration, it is possible to supply cooling air sufficient to sufficiently cool the polyamide multifilament yarn having a high degree of cooling difficulty as compared with the polyester type. When the structure is blown from the center side to the outer peripheral side, in order to obtain the polyamide multifilament yarn of the present invention, since the single fiber protrudes more than necessary, or an excessively long cooling facility is required, the size of the facility is large. This is not preferable because it leads to inconvenience.

  The length of the cooling cylinder is considerably longer than the conventionally proposed annular cooling equipment, and the blowout length of the cooling air is preferably in the range of 600 to 1200 mm, more preferably 800 to 1000 mm. If it is 600 mm or more, the polyamide multifilament yarn of the present invention can be sufficiently cooled, and good mechanical properties and fluff quality can be obtained. If it is 1200 mm or less, the equipment itself is not too long, which is preferable.

  The pressure difference between the inside of the cooling cylinder and the atmospheric pressure is preferably 500 to 1200 Pa, more preferably 600 to 1100 Pa, still more preferably 800 to 1000 Pa, and the cooling air is preferably blown. The differential pressure is a value obtained by measuring the static pressure value of the gas flowing into the cooling cylinder with a static pressure measuring device. In the case of using a conventional horizontal blow cooling device, the fluff quality tends to deteriorate when the cooling air is weakened and the mechanical properties of the multifilament yarn are lowered. However, when an annular cooling device is used, the effect of the differential pressure on the physical properties of the polyamide multifilament yarn of the present invention is small. For example, even if it is about 200 Pa, the mechanical properties can be adjusted only by adjusting the draw ratio. Furthermore, it was found that the occurrence of fluff can be remarkably suppressed by setting the pressure to 500 Pa or more. Moreover, when it is set to 1200 Pa or less, the wind speed does not increase excessively and it is easy to prevent contact between yarns, which is preferable.

Further, the wind speed of the cooling air to said device longitudinally uneven, the upper side air speed _{V U} 10 to 30 m / min, to 40 to 80 m / min the lower side air speed _{V L, V U} is less than _{V L,} V it is preferable _L / _{V U} is 2-3. More preferable ranges of V _U and V _L are 15 to 25 m / min and 50 to 70 m / min, respectively. By changing the wind speed ratio in at least two stages in the longitudinal direction of the apparatus and setting the wind speed range, the fiber physical properties can be improved without deteriorating the thickness unevenness in the longitudinal direction of the yarn. In particular, by producing a slow cooling effect on the upper side, the toughness of the fibers is improved, and the elongation when the strength is the same changes by about 2 to 5%. With regard to such a change in the wind speed ratio, it is preferable to change the position at about 10 to 50% of the total length from the uppermost part of the cooling air blowing part, and more preferably 15 to 45%. As a means for this, by installing a donut-shaped porous member at a position where the ratio is to be changed between the outer cylinder of the cooling cylinder and the rectifying cylinder made of the porous member, the position is used as a boundary between the upper and lower parts of the cylinder. In addition, a means for changing the wind speed above and below by giving a differential pressure, and a means for adjusting the differential pressure between each cylinder and the atmospheric pressure with a two-stage cooling device itself can be considered. There is no problem.

  When trying to produce a polyamide fiber having a total fineness of 200 to 700 dtex and a single fiber fineness of 1 to 2 dtex using a conventional horizontal blow-off cooling facility, the yarn swinging at the spinning part becomes too intense, and the single fibers are in contact with each other. On the other hand, in the method of the present invention described above, even if the cooling wind speed before solidifying the yarn is reduced, the distance between the cooling air and the spun yarn is short, so that the cooling is insufficient. In addition, air collides with each other to form a descending air flow, and the horizontal velocity component of the cooling air can be greatly reduced. Therefore, it is presumed that the yarn can be produced while suppressing yarn shaking.

  Thereafter, the obtained cooling yarn can be wound after applying an oil agent by a known method, taking it up by a take-up roll, stretching it, and then winding it. As the oil agent, a known oil agent can be used. In order to suppress winding of the single yarn on the take-up roll, the adhesion amount is preferably 0.3 to 1.5% by weight, and more preferably 0.5 to 1%. 0.0% by weight.

  The spinning speed defined by the rotation speed of the take-up roll is preferably 500 to 1000 m / min, more preferably 700 to 900 m / min. When the spinning speed is 500 m / min or more, the final production speed is sufficient, and polyamide fibers can be produced at low cost. When the speed is 1000 m / min or less, yarn breakage and frequent occurrence of fluff can be prevented, which is preferable.

The spun yarn obtained by the above-described methods can be subjected to drawing, relaxation heat treatment, winding and the like using a known method, for example, multistage drawing heat treatment at 100 to 250 ° C. in 2 to 3 steps. After the application, it is possible to perform a relaxation heat treatment at 50 to 200 ° C. at 1 to 10%.
In addition, the entanglement to be applied to the yarn can be appropriately selected according to the type of loom and the weaving speed. However, the method according to the present invention does not require excessive entanglement and the number of entanglements of 15 to 30 pieces / m. What is necessary is just to change the kind and provision conditions of a confounding provision apparatus so that can be obtained. Even if it greatly falls below 15 pieces / m or exceeds 30 pieces / m, the high-order process passability tends to deteriorate. Similarly, the entanglement strength may be within a known range.

  Thus, a polyamide multifilament yarn suitable for an air bag having a total fineness of 200 to 700 dtex and a single fiber fineness of 1 to 2 dtex, which could not be produced by a conventionally proposed method, preferably has a strength of 8 to 9 cN / dtex and an elongation of 20 It is possible to obtain -25%, boiling water shrinkage of 4 to 10%, free from yarn unevenness, inexpensively and with excellent yarn-making properties and fluff quality. That is, by the direct spinning drawing method, the yarn can be efficiently produced using a multi-yarn simultaneous drawing method of 8 yarns or more at a spinning speed of 3000 m / min or more, more preferably 3500 m / min or more.

  In the airbag fabric of the present invention, first, the warp yarn having the above-mentioned material and fineness is warped and applied to a loom, and the weft yarn is similarly prepared. As such a loom, for example, a water jet room, an air jet room, a rapier room, and the like can be used. In particular, in order to increase productivity, it is preferable to use a water jet loom which is relatively easy to weave at high speed.

  Next, in order to obtain a fabric for an air bag having a low average dynamic air permeability and a small dynamic air permeability curve index in weaving, the warp yarn tension may be adjusted to 0.11 to 0.34 cN / main · dtex. Preferably, it is 0.15 to 0.28 cN / main · dtex. By setting the warp yarn tension to 0.11 cN / main · dtex or more, the gap between single fibers in the yarn bundle of the multifilament yarn constituting the fabric can be reduced, and the average dynamic air permeability can be reduced. In addition, by setting it to 0.34 cN / main · dtex or less, as described above, when the compressed gas hits the fabric, the multifilament yarn remains free to spread flat with respect to the fabric surface, and the dynamic air permeability curve index is lowered. be able to. When the warp yarn tension is less than 0.11 cN / main · dtex, not only the interfiber spacing in the yarn bundle of the multifilament yarn is increased and the average dynamic air permeability is increased, but also the target woven density cannot be adjusted. There is a case.

  Specific methods for adjusting the warp yarn tension within the above range include a method of adjusting the weft yarn feeding speed in addition to adjusting the warp yarn feed speed of the loom. Whether the warp yarn tension is actually within the above range during weaving is measured, for example, by measuring the tension applied per warp yarn with a tension measuring instrument between the warp beam and the back roller while the loom is running. This can be confirmed by dividing the value by the warp yarn fineness (dtex).

  Subsequent to the weaving step, processing such as scouring and heat setting is performed as necessary.

  The scouring temperature in the scouring process is preferably 20 to 65 ° C, more preferably 30 to 55 ° C. By setting the temperature to 20 ° C. or higher, the strain remaining in the woven fabric after weaving is removed, the single filaments in the multifilament yarn can be moved easily, and the multifilament yarn can spread flat against the fabric surface. A low air permeability fabric can be obtained. On the other hand, by setting the temperature to 65 ° C. or less, large shrinkage of the malfilament can be suppressed and the dynamic permeability curve index can be lowered. Since the multifilament yarn constituting the woven fabric is constrained by the multifilament yarn crossing each other, it cannot be freely shrunk. When scouring is performed at a high temperature of 65 ° C. or higher, the multifilament yarn cannot be freely shrunk, so that the single fiber fineness may be reduced and rearranged so that the single fibers are aligned. In this case, not only the average dynamic air permeability increases, but also the multifilament yarn does not have a play that spreads flat against the fabric surface, so that the dynamic air permeability curve index increases.

  Also in the heat setting process, it is preferable to set the heat setting temperature so that distortion remaining in the woven fabric after weaving can be removed and large shrinkage of the multifilament yarn can be suppressed, as in the scouring process. Specifically, 80 to 150 ° C is preferable, and 100 to 120 ° C is more preferable. By setting it to 80 ° C. or higher, the dynamic air permeability curve index can be lowered. On the other hand, an average dynamic air permeability can be lowered | hung by setting it as 150 degrees C or less.

  The airbag fabric of the present invention can be sewn into a bag shape and attached to an accessory device such as an inflator to make an airbag, which is used for a driver's seat, passenger seat and rear seat, side airbag, etc. can do.

[Measuring method]
Hereinafter, the present invention will be described in detail by way of examples. The definition of each characteristic and the measuring method in the present invention are as follows.

  (1) Total fineness: JIS L1013 (1999) 8.3.1 The positive fineness was measured at a predetermined load of 0.045 cN / dtex by the A method to obtain the total fineness.

  (2) Number of single fibers: Calculated by the method of JIS L1013 (1999) 8.4.

  (3) Single fiber fineness: Calculated by dividing the total fineness by the number of single fibers.

  (4) Strength / Elongation: Measured under constant speed elongation conditions shown in JIS L1013 8.5.1 standard time test. The sample was “TENSILON” UCT-100 manufactured by Orientec Co., Ltd., and the gripping interval was 25 cm and the pulling speed was 30 cm / min. In addition, elongation was calculated | required from elongation of the point which showed the maximum strength in a SS curve.

(5) Boiling water shrinkage ratio: Sampling the raw yarn in a crushed shape, adjusting the temperature in a temperature / humidity adjustment chamber at 20 ° C. and 65% RH for 24 hours or longer, and applying a load equivalent to 0.045 cN / dtex to the sample The thickness L0 was measured. Next, after immersing this sample in boiling water for 30 minutes in an unstrained state, the sample was air-dried for 4 hours in the temperature and humidity control chamber, and a length L1 was measured again by applying a load corresponding to 0.045 cN / dtex to the sample. . The boiling water shrinkage was calculated from the respective lengths L0 and L1 by the following formula.
Boiling water shrinkage = [(L0−L1) / L0] × 100 (%)
(6) Fineness spots: Half values were measured using a Wooster Tester Monitor C manufactured by Zellweger Wooster. Using the INEAT mode, a measurement of 125 m was performed at a yarn speed of 25 m / min.

  (7) Fluff evaluation: The obtained fiber package was rewound at a speed of 500 m / min, and a laser-type fluff detector “Flytech V” manufactured by Heberline was installed at a position 2 mm away from the yarn being rewound. The total number of fluff was converted into the number per 100,000 m and displayed.

(8) Wind speed: An anemono master manufactured by KANOMAX was closely attached to the cooling air outlet at each measurement point. The measuring points are 0, 50, 100 mm from the upper end of the cylinder constituting the cooling air outlet, and every 100 mm up to the lower end of the cylinder every 100 mm, changing the angle by 90 degrees in the circumferential direction. The wind speed average of these four points was taken as the wind speed at each distance from the upper end of the cooling air blowing section. Next, when the vertical wind speed is changed due to equipment, the upper side and the lower side are drawn at the changed position, and when the intentional change of the wind speed ratio is not performed, the upper side and the lower side at a position 300 mm from the upper end. drawn to the side, it was determined respectively V _U and V _L by dividing the interval wind speed integrated by the effective cooling length.
For example, wind velocity V _a position amm than the tubular body top _end, the cooling air blowout length is L, calculation method in the case of intentionally changing the wind speed ratio at the position of 350mm is the as follows.
_{V U = [50 (V 0} + 2V 50 + V 100) +100 (V 100 + V 200) +150 (V 200 + V 300)] / 2/350
V _L = [150 (V ₄₀₀ + V ₅₀₀ ) +100 (V ₅₀₀ + V ₆₀₀ ) +...] / 2 / (L−350)
Note that... Means that the maximum measurement point is similarly calculated and added after 600 mm.

(9) Fabric thickness According to JIS L 1096: 1999 8.5, using a thickness measuring device at 5 different points of the sample, after waiting for 10 seconds under 23.5 kPa under pressure to stabilize the thickness The thickness was measured and the average value was calculated.

(10) Weft density of warp and weft yarns Measured based on JIS L 1096: 1999 8.6.1.
The sample was placed on a flat table, and the number of warp yarns and weft yarns in a 2.54 cm section was counted at five different locations, excluding unnatural wrinkles and tension, and the average value was calculated.

(11) Average dynamic air permeability / dynamic air permeability curve index Measured based on ASTM D6476.
The air permeability tester FX3350 for exclusive use of the airbag of TEXTEST company was used, and the test head was 200 cm ³ . Further, the pressure of the compressed air (START PRESSURE) filled in the test head was adjusted so that the maximum pressure applied to the fabric was 100 ± 5 kPa.

Compressed air filled in the test head is released and applied to a fabric sample, pressure and air permeability are measured over time, and an upper limit pressure (UPPER LIMIT: after reaching maximum pressure) in the obtained pressure-dynamic air permeability curve is measured. 70 kPa) to the lower limit pressure (LOWER LIMIT: 30 kPa), the average value of the dynamic air permeability was determined as the average dynamic air permeability (ADAP).
Further, a dynamic air permeability curve index (Exponent) was calculated from FX3350 from the obtained pressure-dynamic air permeability curve.

(12) Warp yarn tension Using Checkmaster (registered trademark) (type: CM-200FR) manufactured by Kanai Koki Co., Ltd., the warp beam and the back roller are added per warp yarn at the center of the warp beam and back roller during operation. Tension was measured. This value was calculated by dividing by the fineness (dtex) of the warp yarn used.

[Examples 1 to 3]
A nylon 66 chip obtained by liquid phase polymerization was mixed with a 5 wt% aqueous solution of copper acetate as an antioxidant and adsorbed by 68 ppm as copper with respect to the polymer weight. Next, a 50 wt% aqueous solution of potassium iodide and a 20 wt% aqueous solution of potassium bromide were added and adsorbed to 100 parts by weight of the polymer chip to 0.1 parts by weight as potassium, respectively, and a batch type solid state polymerization apparatus was used. Thus, solid phase polymerization was performed to obtain nylon 66 pellets having a relative viscosity of sulfuric acid of 3.8. The obtained nylon 66 pellets were supplied to an extruder, the discharge amount was adjusted so as to obtain two yarns having a total fineness of Table 1 by a metering pump, and arranged in a spinneret, and melt spinning was performed at 295 ° C. Here, the relative viscosity of sulfuric acid is a value obtained by dissolving 2.5 g of a sample in 25 cc of 96% concentrated sulfuric acid and using an Ostwald viscometer at a constant temperature in a thermostatic bath at 25 ° C. Each spinneret is capable of obtaining two yarns having the number of single fibers shown in Table 1, that is, discharge holes twice the number of single fibers shown in Table 1 are 0.22 mm in diameter on four concentric circles. The diameter when the outermost discharge hole groups are concentrically arranged is 14 mm smaller than the inner diameter of the heating cylinder and the cooling cylinder. In Examples 2 and 3, water vapor heated to 260 ° C. from a circular water vapor blowing device having 12 holes having a diameter of 2 mm and a depth of 4 mm at equal intervals was heated 50 mm below the yarn discharge surface at the pressure shown in Table 1. From the position, it was blown obliquely in the direction of 60 ° C. Further, a slow cooling tube having a length shown in Table 1 heated to 300 ° C. is provided directly under the base, and a cooling air flow of 20 ° C. is used using a cylindrical annular cooling device having the cooling air blowing lengths shown in Tables 1 and 2. Was blown so that the differential pressure between the inside of the cooling cylinder and the atmospheric pressure became the value shown in Table 1, and the spun yarn was cooled and solidified. “Fujibon” manufactured by Fuji Filter, which was formed into a cylinder by spirally winding a phenolic resin-impregnated cellulose ribbon having a thickness of 4.6 mm and a filtration accuracy of 40 μm as the cylinder constituting the cooling air blowing part of the cooling cylinder. Using. Further, a punching plate having a donut shape and an aperture ratio of 22.7% was arranged at a position 350 mm from the upper end of the cooling air blowing portion of the cooling cylinder so as to change the speed of the cooling air in the upper and lower sides of the cylinder. Next, a non-aqueous oil agent having a smoothing agent or the like was applied to the cooled and solidified yarn, and it was wound around a spinning take-up roller to take up the spun yarn. Subsequently, the yarn was continuously supplied to the drawing / heat treatment zone, and nylon 66 fibers were produced by a direct spinning drawing method. At this time, the rotation speed of the drawing roller having the highest rotation speed (hereinafter referred to as drawing speed) is set to a constant speed of 3600 m / min, and the overall drawing ratio expressed by the take-off speed and the drawing speed ratio is the value shown in Table 1. Thus, the rotation speed of the take-up roller was adjusted.

  The taken-up yarn is stretched by 5% between the take-up roller and the yarn feeding roller, and then the rotation speed ratio between the yarn feeding roller and the first drawing roller is 2 so that the rotational speed ratio is 2. The second stage of stretching was performed between the first stretching roller and the first stretching roller. Subsequently, a 6% relaxation heat treatment was performed between the second stretching roller and the relaxation roller, the yarn was entangled with the entanglement imparting device, and then wound with a winder. The surface temperature of each roller was set so that the take-up roller was normal temperature, the yarn feeding roller was 40 ° C., the first stretching roller was 140 ° C., the second stretching roller was 230 ° C., and the relaxation roller was 150 ° C. Further, the application amount of the non-aqueous oil agent was adjusted so that the amount of oil adhering to the yarn became 1.0% by weight. The entanglement process was performed by injecting high-pressure air from the direction perpendicular to the running yarn in the entanglement imparting device. A guide for regulating the running yarn was provided before and after the entanglement imparting device, and the pressure of the air to be injected was constant at 0.35 MPa.

  Table 1 shows the fiber production conditions including the upper and lower average wind speed measurements in the cooling cylinder and the properties of the obtained nylon 66 fibers.

  Table 1 also shows the results obtained by rewinding 50 kg of nylon 66 fibers produced using the above method at a speed of 500 m / min and examining the fluff present in the fiber package using a laser type fluff detector.

  In Examples 1 to 3, polyamide fibers having a single yarn fineness of 1 to 2 dtex having sufficient mechanical properties and few fluffs could be obtained.

[Reference Examples 1-3]
A spinneret, in which cooling air is uniformly blown from a horizontal blow cooling device having a length of 1500 mm and 30 m / min is blown so that two yarns can be obtained at a drawing speed of 3600 m / min, has a minimum discharge hole interval. Nylon 66 fibers were produced under the conditions shown in Table 2 using those arranged to be 7.5 mm.

  Table 2 shows the obtained fiber characteristics and the fluff evaluation results.

[Example 4]
(Vertical / Horizontal)
Made of nylon 6,6 of Example 1, having a circular cross-sectional shape, single fiber fineness 1.8 dtex, filament number 192, total fineness 350 dtex, no twist, strength 8.5 cN / dtex, elongation 22.5 % Synthetic fiber multifilament yarn was used as warp and weft.

(Weaving process)
Using the above warp yarn and weft yarn, in a water jet loom, weaved a plain fabric with a warp yarn weaving density of 56 yarns / 2.54 cm and a weft yarn weaving density of 63 yarns / 2.54 cm to obtain a living machine. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 0.28 cN / main · dtex, and the loom rotation speed was 500 rpm.

(Scouring and heat setting process)
After passing through the hot water shrinkage tank of 55 ° C for 20 seconds and drying at 120 ° C for 10 seconds using a non-touch dryer, the breadth rate was 0% and the overfeed rate was 0% using a pin tenter dryer. Under the sizing regulations, heat setting was performed at 120 ° C. for 1 minute to obtain an air bag fabric.

[Example 5]
(Vertical / Horizontal)
The same yarns as those used in Example 4 were used as warp yarns and weft yarns.

(Weaving process)
A raw machine was obtained in the same manner as in Example 4 except that the warp yarn / weft yarn was used and the warp yarn tension during weaving was adjusted to 0.34 cN / main · dtex.

(Scouring and heat setting process)
The raw machine was subjected to the same scouring and heat setting as in Example 4 to obtain an airbag fabric.

[Comparative Example 1]
(Vertical / Horizontal)
The same yarns as those used in Example 4 were used as warp yarns and weft yarns.

(Weaving process)
A raw machine was obtained in the same manner as in Example 4 except that the warp yarn / weft yarn was used and the warp yarn tension during weaving was adjusted to 0.42 cN / main / dtex.

(Scouring and heat setting process)
The raw machine was subjected to the same scouring and heat setting as in Example 4 to obtain an airbag fabric.

[Comparative Example 2]
(Vertical / Horizontal)
Synthetic fiber made of nylon 6,6, having a circular cross-sectional shape, single fiber fineness of 4.9 dtex, number of filaments 72, total fineness of 350 dtex, untwisted, strength 8.5 cN / dtex, elongation 23.5% Multifilament yarn was used as warp yarn and weft yarn.

(Weaving process)
Using the above warp yarn and weft yarn, weaving was carried out under the same fabric configuration and weaving conditions as in Example 4 to obtain a living machine.

(Scouring and heat setting process)
The raw machine was subjected to the same scouring and heat setting as in Example 4 to obtain an airbag fabric.

[Example 6]
(Vertical / Horizontal)
The same yarns as those used in Example 4 were used as warp yarns and weft yarns.

(Weaving process)
Using the above warp yarn and weft yarn, weaving a plain fabric with a warp yarn weaving density of 59 yarns / 2.54 cm and a weft yarn weaving density of 59 yarns / 2.54 cm to obtain a living machine. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 0.34 cN / main · dtex, and the loom rotation speed was 500 rpm.

(Scouring and heat setting process)
The hot water shrinkage tank of 65 ° C. is passed through the raw machine for 20 seconds, dried at 120 ° C. for 10 seconds using a non-touch dryer, and subsequently, the width insertion rate is 0% and the overfeed rate is 0% using a pin tenter dryer. Under the sizing regulations, heat setting was performed at 120 ° C. for 1 minute to obtain an air bag fabric.

[Comparative Example 3]
(Vertical / Horizontal)
The same yarns as those used in Example 4 were used as warp yarns and weft yarns.

(Weaving process)
Using the above warp yarn and weft yarn, weaving was carried out under the same fabric configuration and weaving conditions as in Example 6 to obtain a living machine.

(Scouring and heat setting process)
The hot water shrinkage tank of 80 ° C. is passed through the raw machine for 20 seconds and dried at 120 ° C. for 10 seconds using a non-touch dryer, and subsequently, the width insertion rate is 0% and the overfeed rate is 0% using a pin tenter dryer. Under the sizing regulations, heat setting was performed at 120 ° C. for 1 minute to obtain an air bag fabric.

[Comparative Example 4]
(Vertical / Horizontal)
The same yarns as those used in Example 4 were used as warp yarns and weft yarns.

(Weaving process)
Using the above warp yarn and weft yarn, weaving was carried out under the same fabric configuration and weaving conditions as in Example 6 to obtain a living machine.

(Scouring and heat setting process)
The hot water shrinkage tank of 65 ° C. is passed through the raw machine for 20 seconds, dried at 120 ° C. for 10 seconds using a non-touch dryer, and subsequently, the width insertion rate is 0% and the overfeed rate is 0% using a pin tenter dryer. Under the sizing regulations, heat setting was performed at 180 ° C. for 1 minute to obtain an air bag fabric.

[Example 7]
(Vertical / Horizontal)
The same yarns as those used in Example 4 were used as warp yarns and weft yarns.

(Weaving process)
Using the above warp yarn and weft yarn, weaving a plain fabric with a warp yarn weaving density of 62 / 2.54 cm and a weft yarn density of 56 / 2.54 cm to obtain a living machine. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 0.34 cN / main · dtex, and the loom rotation speed was 500 rpm.

(Scouring and heat setting process)
The hot water shrinkage tank of 60 ° C. is passed through the raw machine for 20 seconds, dried at 120 ° C. for 10 seconds using a non-touch dryer, and subsequently, the width insertion rate is 0% and the overfeed rate is 0% using a pin tenter dryer. Under the sizing regulations, heat setting was performed at 150 ° C. for 1 minute to obtain an airbag fabric.

[Comparative Example 5]
(Vertical / Horizontal)
The same warp yarn and weft yarn as those used in Comparative Example 1 were used.

(Weaving process)
Using the warp and weft yarns, weaving was performed under the same fabric configuration and weaving conditions as in Example 7 to obtain a living machine.

(Scouring and heat setting process)
The raw machine was subjected to the same scouring and heat setting as in Example 7 to obtain an airbag fabric.

[Example 8]
Made of nylon 6,6 of Example 2, having a circular cross-sectional shape, single fiber fineness 1.7 dtex, filament number 136, total fineness 235 dtex, no twist, strength 8.5 cN / dtex, elongation 22.5 % Synthetic fiber multifilament yarn was used as warp and weft.

(Weaving process)
Using the above warp yarn and weft yarn, weaving a plain fabric with a warp yarn weaving density of 72 yarns / 2.54 cm and a weft yarn weaving density of 72 yarns / 2.54 cm to obtain a living machine. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 0.34 cN / main · dtex, and the loom rotation speed was 500 rpm.

(Scouring and heat setting process)
The hot water shrinkage tank of 65 ° C. is passed through the raw machine for 20 seconds, dried at 120 ° C. for 10 seconds using a non-touch dryer, and subsequently, the width insertion rate is 0% and the overfeed rate is 0% using a pin tenter dryer. Under the sizing regulations, heat setting was performed at 120 ° C. for 1 minute to obtain an air bag fabric.

[Comparative Example 6]
(Vertical / Horizontal)
It consists of nylon 6, 6 of Reference Example 2, has a circular cross-sectional shape, single fiber fineness 3.3 dtex, filament number 36, total fineness 235 dtex, no twist, strength 8.5 cN / dtex, elongation 23.5 % Synthetic fiber multifilament yarn was used as warp and weft.

(Weaving process)
Using the warp and weft yarns, weaving was carried out under the same fabric configuration and weaving conditions as in Example 8 to obtain a living machine.

(Scouring and heat setting process)
The raw machine was subjected to the same scouring and heat setting as in Example 8 to obtain an airbag fabric.

[Example 9]
Made of nylon 6 and 6 of Example 3, having a circular cross-sectional shape, single fiber fineness 1.2 dtex, filament number 384, total fineness 470 dtex, no twist, strength 8.5 cN / dtex, elongation 22.5 % Synthetic fiber multifilament yarn was used as warp and weft.

(Weaving process)
Using the above warp yarn and weft yarn, weaving a plain fabric with a warp yarn weaving density of 53 yarns / 2.54 cm and a weft yarn density of 53 yarns / 2.54 cm to obtain a living machine. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 0.28 cN / main · dtex, and the loom rotation speed was 500 rpm.

(Scouring and heat setting process)
The hot water shrinkage tank of 65 ° C. is passed through the raw machine for 20 seconds, dried at 120 ° C. for 10 seconds using a non-touch dryer, and subsequently, the width insertion rate is 0% and the overfeed rate is 0% using a pin tenter dryer. Under the sizing regulations, heat setting was performed at 120 ° C. for 1 minute to obtain an air bag fabric.

[Comparative Example 7]
(Vertical / Horizontal)
The same yarns as those used in Example 9 were used as warp yarns and weft yarns.

(Weaving process)
A raw machine was obtained in the same manner as in Example 9 except that the warp yarn / weft yarn was used and the warp yarn tension during weaving was adjusted to 0.38 cN / main / dtex.

(Scouring and heat setting process)
The raw machine was subjected to the same scouring and heat setting as in Example 9 to obtain an airbag fabric.

[Comparative Example 8]
(Vertical / Horizontal)
It consists of nylon 6 · 6 of Reference Example 3, has a circular cross-sectional shape, single fiber fineness 6.5 dtex, filament number 72, total fineness 470 dtex, no twist, strength 8.5 cN / dtex, elongation 23.5 % Synthetic fiber multifilament yarn was used as warp and weft.

(Weaving process)
Using the warp yarn and the weft yarn, weaving was performed under the same fabric configuration and weaving conditions as in Example 9 to obtain a living machine.

(Scouring and heat setting process)
The raw machine was subjected to the same scouring and heat setting as in Example 9 to obtain an airbag fabric.

  The airbag fabric of the present invention can be suitably used particularly for driver seats, passenger seats, side impact side airbags, and the like. However, the scope of application is not limited to these.

Claims (3)

A fabric for an air bag comprising a synthetic fiber multifilament yarn having a single fiber fineness of 2 dtex or less, an average dynamic air permeability (ADAP) measured based on ASTM D6476 of 500 mm / s or less, and the same rule A dynamic air permeability curve index (Exponent) measured based on the above is 1.5 or less. Synthetic fiber filaments, claim 1 Symbol placement fabric for an airbag number monofilament characterized in that it is a polyamide fiber is at least 100. It is a method of manufacturing the textile fabric for airbags of Claim 1 or 2 , Comprising: Weaving adjusts the warp yarn tension | tensile_strength to 0.11-0.34cN / main * dtex, and is 20-65 degreeC after that. A method for producing a fabric for an air bag, characterized in that the fabric width is fixed so as not to be tensed in the fabric width direction and heat setting is performed at a temperature of 80 to 150 ° C.