JP2010174390A - Woven fabric for airbag, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a woven fabric for an airbag which has flexibility, dimensional stability, or mechanical characteristics required for a base fabric for the airbag, and is capable of reducing shift of stitches of sewn part of the airbag on receiving an occupant after its inflation and expansion, to provide an excellent and inexpensive airbag woven fabric, and to provide a method for producing the woven fabric for the airbag. <P>SOLUTION: The woven fabric for a non-coated airbag is formed of a polyamide fiber having a single fiber fineness of 1 to 3 dtex, and a total fiber fineness of 200-700 dtex, and has a covering factor of the woven fabric of 2,000-2,300, a bending resistance of the fabric according to the ASTM D4032: Circular Bend method of not more than 15N, and also dry a heat shrinkage in lengthwise and transverse directions when treated at 150°C for 30 min of not more than 4%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a non-coated airbag fabric and a method for producing the same.

  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.

  Airbag fabrics used for airbags can be broadly classified into non-coated airbag fabrics that are used without applying resin on the fabric surface, and airbag coated fabrics that are used by applying resin on the fabric surface. Among these, the demand for non-coated airbag fabrics has been increasing in recent years because it can be produced at low cost.

  On the other hand, the airbag is inflated and deployed in the vehicle in a very short time after the vehicle collides, so that the occupant who moves by the reaction of the collision is received and the impact is absorbed to protect the occupant. Is required to have a small air flow rate. In addition, the fabric is required to have a certain level of strength because it needs to withstand the impact when the airbag is activated, and an inflator that generates higher-temperature gas is installed to reduce costs and improve deployment performance. Therefore, heat resistance is also required. Further, the airbag needs to be deployed without any problem even if left in the vehicle for a long period of time to restrain the occupant, and there is a demand for reducing the dimensional change rate. In addition, compactness and flexibility during storage are required from the design characteristics in the vehicle and the relationship with other parts, and further, the demand for cost reduction is further increased.

  Among conventional non-coated airbag fabrics, as a means for improving compactness and flexibility during storage, for example, it is composed of synthetic fibers with a total fineness of 90 to 250 denier, and the vertical and horizontal cover factors are both 900 to 1400. A non-coated side airbag fabric has been proposed (see Patent Document 1). However, this non-coated airbag fabric has a small total fineness and therefore has a low tensile strength, which is a mechanical characteristic required for airbags. It cannot handle the high-pressure inflators in recent years, and breaks when airbags are inflated and deployed. There was a fear. In particular, when polyamide is used as the material, it is necessary to use a material having a large single fiber fineness.

  On the other hand, in order to achieve both low air permeability and low cost, a non-coated airbag fabric manufactured through a roller shrinkage setting process without scouring a living machine is disclosed (see Patent Document 2). However, since this non-coated airbag fabric is made of polyester filament yarn, it has poor heat resistance, and there is a risk that the airbag may be damaged when the fabric is filled with high-temperature gas when the airbag is inflated and deployed.

  Furthermore, an inexpensive method for producing a fabric for an air bag which has low air permeability and excellent mechanical properties and is not subjected to coating or heat setting is disclosed (see Patent Document 3). However, since this technology does not perform heat treatment at a sufficient temperature, the airbag fabric produced by this technology is somewhat inferior in flexibility and storage compactness, and in recent years the storage space may be increasingly reduced. The problem of being unable to fit in a defined space inside the vehicle is occurring. In Patent Document 3, the limit is a polyamide fiber having a single fiber fineness of 4.4 dtex in Examples.

Japanese Patent No. 3457539 (Claim 1, paragraph 0027) JP-A-9-105047 (Claim 1) JP-A-10-168700 (paragraph 0008)

  The present invention has been achieved as a result of studying the above-described problems in the prior art as a subject, and has the flexibility, dimensional stability and mechanical properties required for an air bag base fabric. An object of the present invention is to provide a non-coated airbag fabric and a method for manufacturing a non-coated airbag fabric that can reduce the misalignment of the sewing portion of the airbag when receiving the passenger.

  In order to solve the above problems, the present invention employs any one of the following means.

(1) Requirements for the following [1] to [5] in a woven fabric made of a polyamide fiber multifilament having a single fiber fineness of 1 to 3 dtex and a total fineness of 200 to 700 dtex and woven using a water jet loom. A fabric for an airbag characterized by satisfying
[1] Cover factor is 2000-2300
[2] ASTM D4032: Bending softness in circular bend method is 15 N or less [3] Residual oil fraction is 0.08 wt% to 0.20 wt%
[4] The value obtained by dividing the sliding resistance by the cover factor is 0.19 N or more. [5] The dry heat shrinkage in the vertical and horizontal directions when treated at 150 ° C. for 30 minutes is 4% or less. The non-coated airbag fabric according to [1], wherein the oil content is 0.08 wt% to 0.20 wt%, and the value obtained by dividing the slip resistance of the fabric by the cover factor is 0.19 N or more.

  (3) The non-coated airbag fabric according to (1), wherein the single fiber fineness of the polyamide fiber is in the range of 1 to 2 dtex.

  (4) The non-coated airbag fabric according to (1), wherein the dry heat shrinkage in the vertical and horizontal directions when treated at 150 ° C. for 30 minutes is 3% or less.

  (5) A method for producing a woven fabric for an uncoated airbag according to any one of (1) to (4), wherein the woven fabric is treated in a drying step at 80 ° C. or higher after weaving. A method for producing a woven fabric.

  (6) The method for producing a non-coated airbag fabric according to (5), wherein no scouring treatment is performed after the drying step.

  (7) The method for producing a woven fabric for an uncoated airbag according to (5), wherein the drying step is one step, and a roller-type dryer or a suction drum-type dryer is passed.

  According to the present invention, an airbag fabric having excellent flexibility and dimensional stability and further inexpensive can be provided. In particular, the woven fabric is composed of single fibers having a fineness of 1 to 3 dtex, and the scouring treatment is not applied to the woven fabric, so that the oil content of the woven fabric is appropriately maintained, thereby maintaining necessary and sufficient slip resistance. However, it is possible to provide a woven fabric excellent in process passability during sewing.

  The total fineness of the fiber multifilament constituting the non-coated airbag fabric of the present invention needs to be 200 to 700 dtex. When the total fineness is less than 200 dtex, it is difficult to obtain low air permeability, and mechanical properties required for the airbag such as the strength of the fabric are deteriorated. In addition, since it is difficult to stably obtain high-strength fibers, the quality of the fabric also deteriorates, and the productivity of both the raw yarn and the fabric deteriorates. On the other hand, if it exceeds 700 dtex, it becomes difficult to store the airbag in a compact manner. Further, in order to obtain a multifilament having a single fiber fineness of 1 to 3 dtex and a total filament size exceeding 700 dtex, it is necessary to increase the number of single fibers. It becomes necessary to use fiber yarns formed by combining yarns (multifilaments having a small total fineness), which impairs productivity and increases costs. The range of a preferable total fineness is 280-550 dtex, More preferably, it is 350-470 dtex. By setting the total fineness within this range, the strength, low air permeability, and bag storage compactness of the fabric can be improved in a balanced manner.

  The single fiber fineness of the fibers constituting the polyamide fiber multifilament used in the present invention needs to be 1 to 3 dtex, and preferably 1 to 2 dtex. By making the single fiber fineness within this range, the multifilaments constituting the woven fabric have a finely packed structure, and not only the initial low air permeability can be obtained, but also the densely packed structure is maintained after the environmental aging resistance test. Therefore, low air permeability can be maintained. When the single fiber fineness is less than 1 dtex, it is preferable in terms of low air permeability, but the spinnability is extremely lowered, and a yarn having a single fiber fineness of less than 1 dtex cannot be stably produced. On the other hand, when the single fiber fineness is greater than 3 dtex, the multifilaments constituting the woven fabric are less likely to have a densely packed structure, and it is difficult to obtain low air permeability. In addition, by setting the single fiber fineness within this range, an effect of reducing the rigidity of the multifilament can be obtained, so that the bending resistance of the woven fabric can be 15 N or less, and the storage capacity of the airbag can be improved. it can. Furthermore, even if it is a living machine, sufficient texture can be obtained.

  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, the single fiber fineness of less than 3 dtex within the range of the total fineness of 200 to 700 dtex as in the present invention. 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 the number of single fibers is 100 or more and 3 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 of the present invention have made extensive studies on a method of obtaining a polyamide fiber multifilament having a single fiber number of 100 or more and 3 dtex or less by a method described later, and characteristics of an airbag fabric composed of the polyamide fiber multifilament. did. As a result, after the initial low air permeability and environmental degradation test, the single fiber fineness is 3 dtex or less compared to the case where polyamide fibers having the same total fineness but only different single fiber fineness are used as the airbag fabric by the same method. It has been clarified that the low air permeability, compactness at the time of storage, and sliding resistance are all improved. In particular, with regard to slip resistance and flexibility due to a single fiber fineness of 2 dtex or less, it was found that the same or better results can be obtained without passing through the conventional process, and the productivity is greatly improved. 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 non-coated airbag fabric of the present invention is made of polyamide fibers. Examples of the polyamide fiber 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. Among these, nylon 6 fiber and nylon 66 fiber are particularly excellent in impact resistance and are preferable.

  Polyamide 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, the cross-sectional shape of the single fiber of the polyamide fiber is not particularly limited, and a circular shape, a non-circular shape such as a Y shape, a V shape, a flat shape, or the like, and a hollow portion can also be used. However, a circular shape is preferred because the multifilament tends to have a finely packed structure when it is made into a woven fabric.

  The cover factor (CF) of the non-coated airbag fabric of the present invention is required to be 2000 to 2300, and more preferably 2100 to 2200. By adjusting the cover factor within this range, it is possible to achieve both compact storage required for an airbag and low air permeability. By setting the cover factor to 2000 or more, the air permeability can be reduced. Moreover, compact storage property can be improved by making this cover factor 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).
CF1 = (Dw × 0.9) ^1/2 × Nw + (Df × 0.9) ^1/2 × Nf
Further, it is important that the woven fabric of the present invention has a bending resistance of 15 N or less based on the Circular Bend method defined by ASTM D4032. More preferably, it is 12 N or less. When the bending resistance is greater than 15N, not only does the workability deteriorate when the airbag is folded to be stored in a limited space, but there is a problem that the storage space does not fit in the module. As described above, by setting the single fiber fineness to 1 to 3 dtex, the bending resistance can be 15 N or less, and a sufficient texture can be obtained even with a living machine.

  Further, the fabric of the present invention needs to have a dry heat shrinkage rate of 4% or less in the vertical and horizontal directions when treated at 150 ° C. for 30 minutes. More preferably, it is 3.5% or less, More preferably, it is 3% or less. In order to make it in this range, it is desirable to process by the drying process of 80 degreeC or more. By treating at a temperature of 80 ° C. or higher, the fabric shrinks and stabilizes. When the drying process is performed at a temperature lower than 80 ° C., the dry heat shrinkage rate becomes larger than 4%, the dimensions change while being stored in the airbag module for a long time, and the occupant may not be restrained at the time of inflation and deployment.

  The woven fabric of the present invention has a residual oil content measured according to JIS L1013 (1999) 8.27 b) of 0.08 wt% to 0.20 wt%, and slipping measured according to ASTM D6479-02. It is important that the value obtained by dividing the resistance by the cover factor is 0.19 N or more. The value obtained by dividing the slip resistance by the cover factor refers to the unit cover factor, that is, the slip resistance at a certain cloth filling rate, and represents the difficulty of occurrence of misalignment of a part of the sewing portion of the airbag. It is. By making these within the range, it is possible to obtain a woven fabric excellent in process passability at the time of sewing while maintaining a necessary and sufficient anti-alignment property as an airbag while appropriately maintaining the oil content of the woven fabric. it can. In order to make the residual oil content 0.08 wt% to 0.20 wt%, it is necessary to weave in a water jet loom and not perform a scouring treatment. When weaving, it is desirable to use a pump having a cylinder diameter of Φ18 mm to Φ32 mm in order to adjust the discharge amount of water. If the residual oil content is less than 0.08 wt%, the tear strength is reduced, not only there is a risk of rupturing when the airbag is deployed, but the resistance between the fabric and the sewing needle increases, and the processability during sewing deteriorates. . Further, if the residual oil content is greater than 0.20 wt%, the sliding resistance is reduced, and there is a possibility that the sewn portion will be greatly misaligned when the airbag is deployed, resulting in rupture. Furthermore, when the value obtained by dividing the sliding resistance by the cover factor is less than 0.19 N, the resistance against the misalignment of the sewn portion decreases, so that when the sewn portion receives the internal pressure applied in the initial stage of airbag deployment, the force Cannot be relieved at the sewing portion, and there is a risk of bursting when the stitches are shifted greatly, or the amount of open space at the sewing portion becomes large, and high-temperature air escapes intensively from that portion.

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

  The polyamide multifilament is produced by the following method based on the known 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 heating cylinder or an annular cooling device, it is preferably 8 to 25 mm, more preferably 10 to 20 mm. If the position of the outermost hole is too close to the heating cylinder 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, cooling of the yarn is insufficient. Therefore, it becomes difficult to obtain a polyamide multifilament with high strength and high elongation.

  The spun yarn discharged from the die completes cooling and solidification by sequentially passing through a cylindrical heating tube and a cylindrical annular cooling device. If the single fiber fineness is 1.5 dtex or more, the heating cylinder may or may not be used, but when used, the inner diameter of the cylinder is made the same as that of the annular cooling device, so that the heating cylinder in the cylinder contacts the cooling device. It is preferable to prevent turbulence of the air flow at the location, and it is preferable to cool it using an annular cooling device after heating it so that the atmospheric temperature in the cylinder becomes 250 to 350 ° C. with a length of 50 to 100 mm. . If the heating cylinder length is too long, the thickness unevenness in the longitudinal direction of the polyamide multifilament is greatly deteriorated. On the other hand, when the single fiber fineness is less than 1.5 dtex, an annular cooling device is installed without using a heating cylinder, and cooling of the spun yarn is started more quickly so that the thickness unevenness in the longitudinal direction of the yarn is extreme. However, if the die surface temperature is lowered and the die surface temperature is lowered, it becomes difficult to obtain a polyamide multifilament with high strength and high elongation. It is preferable that hot air of 100 to 250 ° C. is blown out at a constant length within the range. 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 high-strength and high-strength single-fiber fine-filament polyamide multifilament constituting the airbag fabric of the present invention, a structure having the following characteristics is preferable.

  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 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 periphery side, in order to obtain the polyamide multifilament of the present invention, the single fiber protrudes more than necessary, or an excessively long cooling facility is required. This is not preferable.

  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 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. 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 are lowered. However, when an annular cooling device is used, the effect of the differential pressure on the physical properties of the polyamide multifilament 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. It was also 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 with a total fineness of 200 to 700 dtex and a single fiber fineness of 1 to 3 dtex using a conventional horizontal blowing cooling facility, the yarn swinging at the spinning section 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 imparted to the multifilament can be appropriately selected according to the type of loom and the weaving speed. However, if the method according to the present invention is used, it is not necessary to entangle excessively 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 fiber multifilament suitable for an air bag having a total fineness of 200 to 700 dtex and a single fiber fineness of 1 to 3 dtex, which could not be produced by the 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.

  The non-coated airbag fabric of the present invention uses the multifilament having the above-mentioned material and fineness. First, warp warp yarn and apply it to a loom to prepare a weft yarn in the same manner. As such a loom, it is important to use a water jet loom. By using the water jet loom, most of the oil adhering to the warp yarn and the weft yarn during weaving can be removed, so that it is not necessary to carry out scouring after weaving. When weaving using a weaving machine other than the water jet loom, such as an air jet loom or rapier loom, oil adhering to the yarn does not fall during weaving, so it is essential to carry out scouring from the viewpoint of misalignment and flame retardancy This leads to high costs.

  When the weaving process is finished, the fabric is dried in the drying process. It is important that the drying temperature is 80 ° C. or higher. When the temperature is less than 80 ° C., the dry heat shrinkage ratio is large, the dimensional stability is deteriorated, and the function as an airbag may not be performed during inflation and deployment.

  In addition, the drying step includes a one-step dryer, and it is preferable to use a roller dryer or a suction drum dryer as the dryer. The roller-type dryer refers to a hot-fluid type machine that is dried by hot air. The roller-type dryer can be dried at a low tension without touching anything other than the guide roll installed in the dryer. By using these dryers, the tension applied to the fabric during drying can be minimized, so that the fabric can be sufficiently shrunk in the drying process, and a fabric excellent in dimensional stability can be obtained. .

  The non-coated airbag fabric of the present invention can be sewn into a bag shape and attached to an accessory such as an inflator to make an airbag, and can be used for a driver seat, a passenger seat, a rear seat, and the like. .

[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 According to JIS L1013 (1999) 8.3.1 A method, the positive fineness was measured at a predetermined load of 0.045 cN / dtex to obtain the total fineness.

(2) Number of single fibers It 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 the constant speed elongation condition 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 The raw yarn is sampled into a husk shape, adjusted in a temperature / humidity adjustment chamber at 20 ° C. and 65% RH for at least 24 hours, and subjected to a load equivalent to 0.045 cN / dtex for length. the L ₀ was measured. Next, after immersing the sample in boiling water for 30 minutes in an unstrained state, the sample was air-dried for 4 hours in the temperature / humidity adjusting chamber, and a length L ₁ was measured by applying a load equivalent to 0.045 cN / dtex to the sample again. did. The boiling water shrinkage was calculated from the respective lengths L ₀ and L _{1 according} to the following equation.
Boiling water shrinkage = [(L ₀ −L ₁ ) / L ₀ ] × 100 (%)
(6) 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 location 2 mm away from the yarn being rewound and detected. The total number of fluff was converted into the number per 100,000 m and displayed.

(7) Wind speed
An anemone master manufactured by KANOMAX was in close contact with 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, when the wind speed at the position amm from the upper end of the cylinder is Va and the cooling air blowing length is L, the calculation method when the wind speed ratio is intentionally changed at the position of 350 mm is 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.

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

(9) Woven density 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.

(10) Fabric weighting In accordance with JIS L 1096: 1999 8.4.2, three test pieces of 20 cm × 20 cm were collected, each mass (g) was measured, and the average value was the mass per 1 m ² (g / M ² ).

(11) Tensile strength JIS K 6404-3 In accordance with test method B (strip method), for each of the vertical and horizontal directions, five test pieces were collected, the yarn was removed from both sides of the width to a width of 30 mm, and a constant speed tension type testing machine, The test piece was pulled at a grip interval of 150 mm and a tensile speed of 200 mm / min, and the maximum load until cutting was measured, and the average value was calculated for each of the vertical and horizontal directions.

(12) Elongation at break JIS K 6404-3 In accordance with test method B (strip method), for each of the vertical direction and the horizontal direction, five test pieces are sampled, the thread is removed from both sides of the width to make a width of 30 mm, and 100 mm intervals are provided at the center of these test pieces. With a marked line, with a constant-speed tension type testing machine, pull until the specimen is cut at a grip interval of 150 mm and a pulling speed of 200 mm / min, read the distance between the marked lines when reaching the cutting, The breaking elongation was calculated, and the average value was calculated for each of the vertical and horizontal directions.
E = [(L-100) / 100] × 100
Where E: elongation at break (%),
L: Distance (mm) between marked lines at the time of cutting.

(13) Tear strength JIS K 6404-4 According to test method B (single tongue method), test specimens with a long side of 200 mm and a short side of 76 mm were taken on the vertical and horizontal sides, respectively, and 5 specimens were collected respectively, and the test piece was perpendicular to the center of the short side. A 75 mm incision was made, and the specimen was torn with a constant speed tension type tester at a grip interval of 75 mm and a tensile speed of 200 mm / min until the specimen was pulled, and the tear load at that time was measured. From the obtained chart recording line of the tearing load, three points were selected from the maximum points excluding the first peak in descending order, and the average value was taken. Finally, an average value was calculated for each of the vertical and horizontal directions.

(14) Air permeability According to JIS L 1096: 1999 8.27.1 A method (Fragile type method), the air permeability when tested at a test differential pressure of 19.6 kPa was measured. Samples of about 20cm x 20cm are collected from 5 different locations of the sample, attached to one end of a cylinder with a diameter of 100mm, fixed so that there is no air leakage from the mounting location, and a test differential pressure using a regulator. It adjusted to 19.6 kPa, the air quantity which passes a test piece at that time was measured with the flowmeter, and the average value about five test pieces was computed.

(15) Bending softness Measured according to ASTM D4032: Circular Bend method.

(16) Dry heat shrinkage rate Test specimens of 30 cm × 30 cm are collected from three different places, and three 20 cm marked lines are drawn so as to be parallel to the weaving yarn in both the vertical and horizontal directions. The test piece is placed in a dryer set at 150 ° C. so that no tension is applied, and contracted for 30 minutes. After the treatment, after adjusting for 24 hr in the standard state (25 ° C., 65 Rh%), the distance between the marked lines is measured, the dry heat shrinkage is calculated by the following formula, and the average value is calculated for each of the vertical direction and the horizontal direction. .
Dry heat shrinkage (%) = [(20−L) / 20] × 100
Here, L: distance between marked lines (cm).

(17) Residual oil content of woven fabric Samples of about 30 cm × 30 cm are taken from three different locations, and warp yarns and weft yarns are frayed from the test pieces, and each of the decomposed yarns becomes 5 g, for a total of 10 g. The sample was collected as described above, and the diethyl ether extract was measured according to JIS L1013 (1999) 8.27 b), and the average value thereof was defined as the oil adhesion amount, and the residual oil fraction was calculated according to the following formula.

Residual oil content (%) = (W / 10) × 100
Where, W: oil adhesion amount (g)
(18) Sliding resistance The sliding resistance in the vertical direction and the horizontal direction was measured according to ASTM D6479-02. In Table 2, the values are divided by the cover factor.

[Examples 1 and 2]
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, and the discharge amount was adjusted so as to obtain two yarns having a total fineness of Table 1 by a metering pump, and the mixture was arranged in a spinneret, and melt spinning 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 group was concentrically arranged was 14 mm smaller than the inner diameter of the heating cylinder and the cooling cylinder. A 100 mm heating cylinder heated to 300 ° C. is provided immediately below the base, and the cooling air of 20 ° C. is cooled between the inside of the cooling cylinder and the atmospheric pressure using the cylindrical annular cooling device having the cooling air blowing length shown in Table 1. The pressure was increased so that the differential pressure was the value shown in Table 1, and the air was blown to cool and solidify the spun yarn. “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 the yarn 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 and 2, it was possible to obtain polyamide fibers having a single yarn fineness of 1 to 2 dtex having sufficient mechanical properties and few fluff.

[Reference Examples 1 and 2]
By uniformly blowing a cooling air of 30 m / min from a horizontal blow cooling device having a length of 1500 mm, two yarns with a total fineness of 470 dtex and 72 single fibers can be obtained at a drawing speed of 3600 m / min. Example 1 except that the spinneret was arranged so that the minimum value of the discharge hole interval was 7.5 mm, and production of nylon 66 fiber was attempted under the conditions shown in Table 1. The same was done.

  The obtained fiber characteristics and the results of fluff evaluation are shown in Table 1.

[Example 3]
(Weaving process)
Using the fibers of Example 1 as warp and weft, a plain weave with a weaving density of 53 / 2.54 cm was woven in a water jet loom to obtain a wet wetting machine.

(Drying process)
Next, this wet wet machine was dried at 120 ° C. using a hot-fluid drier to obtain an airbag fabric.

  The characteristics of the obtained airbag fabric are shown in Table 2. The obtained airbag fabric was excellent in anti-missing property, flexibility and dimensional stability.

[Comparative Example 1]
(Weaving process / Drying process)
Using the fibers of Reference Example 1 as warp yarns and weft yarns, weaving and drying were performed in the same manner as in Example 3 to obtain airbag fabrics.

  The resulting airbag fabric was not satisfactory in terms of anti-missing property and flexibility.

[Comparative Example 2]
(Weaving process)
A plain fabric having a weaving density of 46 / 2.54 cm was woven in the water jet loom using the fibers of Example 1 as warp and weft yarns to obtain a wet wetting machine.

(Drying process)
Next, this wet wet machine was dried at 120 ° C. using a hot-fluid drier to obtain an airbag fabric.

  The obtained airbag fabric did not satisfy the anti-missing property.

[Comparative Example 3]
(Weaving process)
Using the fibers of Example 1 as warp and weft yarns, weaving was performed in the same manner as in Example 3 to obtain a wet greening machine.

(Drying process)
Next, the wet wet machine was dried at 60 ° C. using a hot-fluid drier to obtain an airbag fabric.

  The obtained airbag fabric did not satisfy flexibility or dimensional stability.

[Example 4]
(Weaving process)
Using the fibers of Example 2 as warp yarns and weft yarns, a plain woven fabric having a weaving density of 59 yarns / 2.54 cm was woven in a water jet loom to obtain a wet wetting machine.

(Drying process)
Next, the wet wet machine was dried at 80 ° C. using a suction-type dryer to obtain an airbag fabric.

  The characteristics of the obtained airbag fabric are shown in Table 2. The obtained airbag fabric was excellent in anti-missing property, flexibility and dimensional stability.

[Comparative Example 4]
(Weaving process / Drying process)
Using the fibers of Reference Example 2 as warp yarns and weft yarns, weaving and drying were performed in the same manner as in Example 4 to obtain airbag fabrics.

  The obtained airbag fabric did not satisfy the anti-missing property.

[Comparative Example 5]
(Weaving process / Drying process)
Using the fibers of Example 2 as warp and weft, weaving and drying were performed in the same manner as in Example 4 to obtain a woven fabric.

(Scouring process)
Next, this woven fabric was scoured with hot water at 60 ° C. and then dried at 160 ° C. to obtain an airbag fabric.

  The obtained airbag fabric was inferior in productivity and did not satisfy the residual oil content.

[Comparative Example 6]
(Weaving process)
Using the fibers of Example 2 as warp and weft, a plain fabric having a weaving density of 59 yarns / 2.54 cm was woven with a rapier loom to obtain a living machine.

(Drying process)
Next, this raw machine was dried at 80 ° C. using a suction-type dryer to obtain an airbag fabric.

  The obtained airbag fabric did not satisfy the anti-missing property.

  The airbag fabric according to the present invention combines the flexibility, dimensional stability and mechanical properties required for airbag fabrics, and is excellent in productivity. Therefore, the airbag fabric of the present invention can be suitably used particularly for a driver seat, a passenger seat, a side airbag for side collision, and the like, but the application range is not limited thereto.

Claims (6)

A woven fabric made of polyamide fiber multifilaments having a single fiber fineness of 1 to 3 dtex and a total fineness of 200 to 700 dtex, and woven using a water jet loom, satisfying the following requirements [1] to [5] A fabric for air bags characterized by
[1] Cover factor is 2000-2300
[2] ASTM D4032: Bending softness in circular bend method is 15 N or less [3] Residual oil fraction is 0.08 wt% to 0.20 wt%
[4] The value obtained by dividing the sliding resistance by the cover factor is 0.19 N or more. [5] The dry heat shrinkage in the vertical and horizontal directions when treated at 150 ° C. for 30 minutes is 4% or less.   The non-coated airbag fabric according to claim 1, wherein the single fiber fineness of the polyamide fiber is in the range of 1 to 2 dtex.   The woven fabric for an uncoated airbag according to claim 1, wherein the dry heat shrinkage in the vertical and horizontal directions when treated at 150 ° C for 30 minutes is 3% or less.   A method for producing a non-coated airbag fabric according to any one of claims 1 to 4, wherein the non-coated airbag fabric is treated by a drying step at 80 ° C or higher after weaving.   6. The method for producing a non-coated airbag fabric according to claim 5, wherein no scouring treatment is performed after the drying step.   6. The method for producing a non-coated airbag fabric according to claim 5, wherein the drying step is one step, and a roller-type dryer or a suction drum-type dryer is passed.