JP5359714B2 - Airbag base fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve various problems of conventional technology relating to a base cloth for an airbag, and to provide the base cloth for airbag having excellent flexibility, thin thickness and light weight while keeping mechanical properties of conventional base cloth for airbag. <P>SOLUTION: The base cloth for airbag is composed of a polyamide multifilament and satisfies following requirements. The cover factor (CF) (CF=&radic;(D1 (dtex)&times;0.9)&times;S1 (filaments/2.54 cm)+&radic;(D2 (dtex)&times;0.9)&times;S2 (filaments/2.54 cm)) of the base cloth for airbag is 1,600-2,300, the values defined by formula 1 and formula 2 are 0.030-0.036 N/(number of filaments)&times;dtex, the polyamide multifilament has a total fineness of 200-500 dtex, a single fiber fineness of 1-4 dtex, a strength of &ge;9.0 cN/dtex and an elongation of &ge;20%, and not less than 95 wt.% of the polyamide constituting the polyamide multifilament is hexamethylene adipamide component. The formula 1: T1 (N/cm)/D1 (dtex)/S1 (filaments/2.54 cm); and the formula 2: T2 (N/cm)/D2 (dtex)/S2 (filaments/2.54 cm), wherein T1 is a tensile strength in the longitudinal direction (N/cm); T2 is a tensile strength in the lateral direction (N/cm); D1 is a total fineness in the longitudinal direction (dtex); D2 is a total fineness in the lateral direction (dtex); S1 is a cloth density in the longitudinal direction (filaments/2.54 cm); and S2 is a cloth density in the lateral direction (filaments/2.54 cm). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an airbag base fabric that is excellent in flexibility, thinness, and lightness while maintaining mechanical characteristics as compared with a conventional airbag base fabric.

  With the improvement of traffic safety awareness, an increasing number of vehicles are equipped with airbags as standard to ensure the safety of passengers in the event of a car accident.

  The airbag is inflated and deployed abruptly in the vehicle in a very short time after the vehicle collides, so as to receive an occupant moving due to the reaction of the collision and absorb the impact to protect the occupant. In view of this action, the fabric constituting the airbag is required to have a certain strength or more because it is necessary to withstand an impact during operation. Currently, nylon 66 multifilaments with a total fineness of 470 or 350 dtex and a strength of 8.5 cN / dtex are mainly used for airbag fabrics for Japanese cars.

  Recently, there are high development needs such as weight reduction and compactness during storage due to the improvement of environmental awareness, design in the car and the relationship with other parts. Is also growing.

  In order to solve the above-mentioned needs, in order to provide an air bag having a stitched portion that is lightweight and has high pressure resistance while maintaining high strength, the fineness is 400 dtex or less and the strength is 8.85 cN / dtex or more. Using multi-filaments with high strength, stitches with two rows of stitches with a stitch count of 20 stitches or more and a stitching distance of 4 stitches / cm or more and a distance between stitches of 2.2 to 4 mm An air bag has been proposed. (For example, see Patent Document 1)

    However, Patent Document 1 does not describe the quality related to fluff and the like generated in the manufacturing process of nylon 66 fiber used as an air bag yarn. It was not at a satisfactory level as a bag yarn. Multifilaments with a lot of fluff have had the problem that productivity has deteriorated and the recently increasing low-cost requirements cannot be achieved.

    Examples of methods for obtaining conventional high-strength nylon 66 fibers include Patent Documents 2 and 3.

In order to provide polyamide fibers with less fuzz suitable for use in various industrial materials such as tire cords for rubber reinforcement, belt cords, computer ribbons, airbag base fabrics, etc. When producing a high-strength polyamide fiber by stretching by two or more stages of multi-stage stretching, at least the take-up after the first-stage drawing to the second-stage drawing is taken, and the delivery is slip-on-roll stretching, and A method for producing a polyamide fiber has been proposed in which the strain rate of stretching after completion of 80% of the total stretching ratio is 300 min ⁻¹ or less. (For example, see Patent Document 2)

Although it is described that a high-strength polyamide fiber of 10.35 to 10.97 g / d (9.1 to 9.7 cN / dtex) can be obtained by this production method, the strain rate (dV / dX) is 300 min ^{−. In} order to make it ¹ or less, the roller before final drawing having a rough surface roughness was used, and the yarn was slip-drawn, so that the roller was severely worn and there was a problem in stable productivity. Further, the number of fluffs of the obtained yarn is 2 to 17 million / m, and it can be suitably used for tire cords used by twisting, but it is a fiber for an airbag that is woven without twisting and densely. As it was not a satisfactory level. Further, the fibers shown in the examples have a total fiber fineness of 1890 denier (2100 dtex), and a method for producing a fiber having a total fiber fineness of 200 to 500 dtex used as a general airbag fiber is not disclosed. In addition, although there is no description of the elongation of the obtained fiber, the elongation greatly decreases with increasing strength, so further fluffing occurs when weaving at high speed, the number of stops increases, and production There was a problem that the performance decreased.

  Further, in order to provide a high toughness nylon 66 fiber having high strength and high elongation, at least 95 mol% is composed of a hexamethylene adipamide unit, and a relative viscosity of sulfuric acid is 3.0 or more. Nylon 66 having a strength of 11.0 g / d or more, an elongation of 16% or more, a boiling water shrinkage of 4.0% or less, and a specified treatment agent of 0.3 to 2.0% by weight per fiber weight. Fiber has been proposed. (For example, Patent Document 3)

According to the examples of the document, it is described that nylon 66 fibers having a strength of 12 to 12.8 g / d (10.6 to 11.3 cN / dtex) and a cut elongation of 18.9 to 19.2% can be obtained. However, since the number of times of thread trimming is 0.5 to 0.62 times / 10 ⁷ m and the number of fluffs is larger than this, although it can be suitably used in tire cord applications used by twisting, It was not a satisfactory level as a fiber for an airbag used without twisting. Further, the fibers shown in the examples have a total fiber fineness of about 1260 denier (1400 dtex), and a method for producing fibers having a total fiber fineness of 200 to 500 dtex used as a general airbag fiber is not disclosed. .

On the other hand, it is a copolymerized polyamide composed of 95 to 80% by weight of hexamethylene adipamide component and 5 to 20% by weight of capramide component, and has a yarn strength of 9 g / d or more, an elongation of 18% or more, and a single fiber fineness of 3 There has been an invention relating to an airbag base fabric that is lightweight, flexible, excellent in storage properties, and excellent in mechanical properties by using an airbag base fabric using a polyamide fiber of .5 denier or more. (For example, see Patent Document 4)
However, there is a problem that the melting point of the obtained fiber is low and the heat resistance is poor.

Therefore, a polyamide fiber having a yarn strength of 7.0 to 12 cN / dtex, a polyparaphenylene benzobisoxazole fiber having a yarn strength of 15 cN / dtex or more, an aramid fiber, etc. are mixed to provide excellent storage properties and a necessary base. A method of manufacturing an air bag base fabric having cloth strength has been invented. (For example, see Patent Document 5)
However, all the fibers having a raw yarn strength of 15 cN / dtex or more are expensive, and cannot meet the low cost requirement, and there is a problem that the work is complicated because the two types of fibers are mixed and woven. .

JP 2005-138704 A JP-A-11-172523 JP-A-6-299411 JP-A-4-176750 JP 2007-138356 A

  The present invention solves the problems of the prior art, and provides an airbag base fabric that is excellent in flexibility, thinness, and lightness while maintaining mechanical characteristics with respect to a conventional airbag base fabric. For the purpose.

According to the present invention for solving this problem, an airbag base fabric composed of polyamide multifilaments, wherein the cover factor (CF) of the airbag base fabric is in the range of 1600 to 2300. Formulas 1 and 2 are 0.030 to 0.036 N / main · dtex, and the polyamide multifilament has a total fineness of 200 to 500 dtex, a single fiber fineness of 1 to 4 dtex, and a strength of 9.0 cN / dtex or more, There is provided an airbag base fabric characterized by having an elongation of 20% or more and 95% by weight or more of the polyamide constituting the polyamide multifilament is a hexamethylene adipamide component.
CF = √ (D1 (dtex) × 0.9) × S1 ( the /2.54cm)+√ (D2 (dtex) x0.9) × S2 ( present per 2.54 cm)
Formula 1 = T1 (N / cm) / D 1 (dtex) / S1 (line / 2.54 cm)
Formula 2 = T2 (N / cm) / D2 (dtex) / S2 (line / 2.54 cm)
here,
T1: Tensile strength in the vertical direction (N / cm)
T2: Tensile strength in the horizontal direction (N / cm)
D1: Total fineness in the vertical direction (dtex)
D2: Total fineness in the horizontal direction (dtex)
S1: Textile density in the vertical direction (main / 2.54cm)
S2: Woven fabric density in a horizontal direction (book / 2.54cm)
In the airbag fabric of the present invention,
The total fineness of the multifilament is in the range of 400 to 500 dtex,
The single filament fineness of the multifilament is in the range of 1 to 2 dtex,
The cover factor is in the range of 1600 to 2200, and the resin is coated on at least one side,
The discharge amount of the resin coated on at least one side is in the range of 5 to 40 g / m ² ;
The bending resistance based on ASTM D4032: 2002 is 20 N or less,
A preferable condition is that the thickness is 0.3 mm or less.

Further, in the raw yarn constituting the airbag fabric of the present invention, the total fineness is 200 to 500 dtex, the single fiber fineness is 1 to 4 dtex, the strength is 9.0 cN / dtex or more, and the elongation is 20% or more. In addition, it is a preferable condition that the fineness unevenness is composed of polyamide multifilaments of 1.2% or less.
Applying 100 to 400 Pa of steam heated to 200 ° C. to 350 ° C. to the fibers extruded from the spinneret by melt spinning of polyamide, then passing through a slow cooling tube, cooling using an annular cooling device, and then stretching. Are preferable conditions, and by applying these conditions, further excellent effects can be expected.

  According to the present invention, the polyamide multifilament constituting the conventional airbag fabric is made of a yarn having high strength and high elongation, small single fiber fineness, and excellent fluff quality. Further, it is possible to provide an airbag base fabric excellent in flexibility, thinness and lightness while maintaining mechanical characteristics at low cost.

  Hereinafter, the present invention will be described in detail.

  The air bag base fabric of the present invention needs to be made of polyamide multifilament. By using a polyamide multifilament, flexibility is improved and a base fabric having excellent storage compactness can be obtained. Polyester fibers cannot provide high-strength fibers with less fluff suitable for current high-speed weaving, and are inferior in terms of heat resistance of the airbag fabric. The multifilament constituting the airbag fabric of the present invention requires that the polyhexamethylene adipamide component having excellent impact resistance and heat resistance is 95% by weight or more, and 97% by weight or more. It is preferable. When the polyhexamethylene adipamide component is less than 95% by weight, the heat resistance of the polyhexamethylene adipamide is lowered, which is not preferable. The polyamide multifilament may contain a copolymer component as long as it is 5% by weight or less. Examples of the copolymer component used in the present invention include ε-caproamide, tetramethylene adipamide, hexamethylene sebacamide, hexamethylene isophthalamide, tetramethylene terephthalamide, and xylylene phthalamide. Additives such as weathering agents, heat-resistant agents, and antioxidants can be added to the polyamide chips that have been increased in viscosity by solid-phase polymerization, if necessary, and melt-spun. Some or all of the additives may be added during polymerization, or may be mixed by other methods. Moreover, in order to adjust the amino terminal group amount, the polyamide chip may or may not contain diamine, monocarboxylic acid, or the like, and may be adjusted so that the target amino terminal group amount is appropriately obtained.

  The sulfuric acid relative viscosity of the polyamide resin used for the polyamide multifilament constituting the airbag fabric of the present invention is preferably 3.5 or more, more preferably 3.6 to 4.0. When the sulfuric acid relative viscosity is less than 3.5, it is difficult to obtain a high-strength and high-strength polyamide multifilament constituting the airbag base fabric of the present invention.

  The total fineness of the fibers constituting the airbag fabric of the present invention needs to be 200 to 500 dtex. When the total fineness is less than 200 dtex, the tear strength and flammability of the base fabric are lowered. In addition, since it is difficult to stably obtain high-strength fibers, the quality of the base fabric also deteriorates, and the productivity of both the raw yarn and the base fabric deteriorates. Furthermore, since the production efficiency is deteriorated, it is not preferable as an airbag application that is strict in cost requirements. On the other hand, if it exceeds 500 dtex, the number of single yarns is increased to obtain a polyamide multifilament having a single fiber fineness of 4 dtex or less according to the present invention, which impairs productivity. Furthermore, in the case of a polyamide multifilament having a single fiber fineness of 2 dtex or less, the number of single yarns is too large, and spinning is extremely difficult with the current technology. Therefore, a fiber yarn formed by combining two or three yarns. It will be necessary to reduce the productivity. Further, the obtained base fabric is not preferable because unevenness is easily formed, and the amount of the resin required for coating the resin is increased, the flexibility, thinness and lightness are deteriorated, and the production cost is increased. The range of a preferable total fineness is 350-500 dtex, More preferably, it is 400-500 dtex.

  The single fiber fineness is required to be 1 to 4 dtex, preferably 1 to 3 dtex, and more preferably 1 to 2 dtex. When the single fiber fineness is less than 1 dtex, it is difficult to stably obtain high-strength fibers even if a method for obtaining a polyamide multifilament constituting the airbag fabric of the present invention described later is used. In addition, by setting the single fiber fineness to 4 dtex or less, even if weaving at a lower woven density compared to 4 dtex or more used for the fibers constituting the conventional airbag fabric, the fineness is lower than the conventional one. Even if a polyamide multifilament is selected, slip resistance, breathability and flexibility are improved. Furthermore, these characteristics are drastically improved by setting to 1 to 2 dtex. As a result, it has been found that the weight of the airbag is dramatically improved as compared with the conventional airbag fabric.

  The strength of the polyamide multifilament constituting the airbag fabric of the present invention needs to be 9 cN / dtex or more, and more preferably 9.15 cN / dtex or more. Conventionally, the yarn used for airbag fabrics is in the range of 8 to 8.5 cN / dtex, and by setting the strength to 9 cN / dtex or more, it is the conventional level even within the cover factor (CF) range described below. The mechanical strength equivalent to that of the high-density base fabric can be maintained. At the same time, the elongation of the polyamide multifilament needs to be 20% or more, and if it is less than 20%, fluff and yarn breakage in the yarn production process increase, and fluff in the weaving process also occurs. Production efficiency decreases. More preferably, it is 20-25%, More preferably, it is 22-25%. By setting it as this range, the toughness of the airbag fabric and the rupture work can be increased.

  Regarding the fibers constituting the airbag fabric, it has been studied over many years to reduce both the total fineness and the single fiber fineness, and to increase the strength. However, as in the present invention, the total fineness is 200 to 500 dtex. There is no actual example of a polyamide multifilament having a single fiber fineness of 1 to 4 dtex in the range of the above, a strength of 9.0 cN / dtex or more, and an elongation of 20% or more. Naturally, there is no example disclosed about the characteristic provided when the fabric for airbags is comprised using such a polyamide multifilament. In the conventional study, the sliding resistance, low air permeability and flexibility of the base fabric are improved by reducing the single fiber fineness, but there is a tendency to be saturated when the single fiber fineness is reduced to about 3 to 4 dtex. In addition, the number of single yarns increases as the fineness of the single fiber decreases, and fusing occurs due to single yarn collision in the cooling and solidification process, resulting in frequent fluff and yarn breakage in the drawing process, resulting in productivity. As a result, the quality of the obtained airbag base fabric was not satisfactory. Moreover, in order to obtain a high-strength polyamide multifilament, it is necessary to adopt a high draw ratio, and even in fibers having a single fiber fineness of 4 to 6 dtex, which are used for conventional airbag fibers, fluff and yarn breakage Frequently occurs, and the productivity is lowered. When the single fiber fineness is 4 dtex or less, there is a problem of further yield reduction. Furthermore, since the elongation decreases as the strength of the polyamide multifilament increases, the fluff in the weaving process also increases as described above, and there is a problem that the frequency of stopping the loom increases. The present inventors have intensively studied and have a single fiber fineness of 1 to 4 dtex in a total fineness range of 200 to 500 dtex, a strength of 9.0 cN / dtex or higher, and an elongation of 20% or higher. A method for stably obtaining a polyamide multifilament of the same degree and the characteristics of an airbag base fabric composed of the multifilament were obtained, and the airbag base fabric of the present invention was obtained using a conventional polyamide multifilament. Even if weaving at a lower weaving density than the base fabric used, or selecting a polyamide multifilament with a lower fineness than conventional ones, it is possible to obtain the same base fabric strength, sliding resistance, and low air permeability. As a result, it has been clarified that it is excellent in flexibility, thinness and lightness.

  Further, the fineness unevenness of the polyamide multifilament of the present invention is preferably 1.2% or less, more preferably 0.2 to 1.0%, and still more preferably 0.2 to 0.8%. When the fineness unevenness is 1.2% or more, the stretchability is deteriorated. Therefore, in the polyamide multifilament constituting the airbag fabric of the present invention that is stretched at a high magnification, fluff is smaller than fibers of less than 9 cN / dtex. It is easy to generate and is not preferable.

  The cover factor (CF) of the airbag fabric of the present invention is required to be 1600 to 2300, preferably 1700 to 2100, and more preferably 1700 to 2000. In addition, when the resin is coated on at least one side of the base fabric, it is preferably 1600 to 2200, and more preferably 1700 to 2000. By setting the cover factor within this range, an airbag base fabric excellent in flexibility, thinness and lightness can be obtained.

Here, the cover factor (CFw) of the warp yarn of the base fabric and the cover factor (CFf) of the weft yarn are values calculated from the total fineness of the yarn used for the warp yarn or the weft yarn and the base fabric density, The warp yarn total fineness is Dw (dtex), the weft total yarn fineness is Df (dtex), the warp yarn base fabric density is Nw (main / 2.54 cm), and the warp yarn base fabric density is Nf (main / 2.54 cm). ) Is expressed by the following formula, and CF is the sum of CFw and CFf.
CFw = (Dw × 0.9) ^1/2 × Nw
CFf = (Df × 0.9) ^1/2 × Nf
The airbag fabric according to the present invention is required to have a value represented by the following formula of 0.030 to 0.036 N / line · dtex, more preferably 0.032 to 0.036 N / line · dtex. It is.
Formula 1 = T1 (N / cm) / D1 (dtex) / S1 (line / 2.54 cm)
Formula 2 = T2 (N / cm) / D2 (dtex) / S2 (line / 2.54 cm)
(here,
T1: Tensile strength in the vertical direction (N / cm)
T2: Tensile strength in the horizontal direction (N / cm)
D1: Total fineness in the vertical direction (dtex)
D2: Total fineness in the horizontal direction (dtex)
S1: Textile density in the vertical direction (main / 2.54cm)
S2: Woven fabric density in a horizontal direction (book / 2.54cm)
It is. )
Here, Formula 1 and Formula 2 are values obtained by dividing the tensile strength in the vertical direction and the horizontal direction by the total fineness of the vertical and horizontal yarns and the fabric density, and when the total fineness is 200 to 500 dtex, 0.030 In the range of ˜0.036 N / main · dtex, the base fabric has the same tensile strength as the base fabric obtained with the conventional polyamide multifilament, but also has the same weight as the base fabric. It can be said that the fabric has excellent tensile strength. If it is less than 0.030 N / main · dtex, it is impossible to achieve both tensile strength and light weight, or a base fabric having excellent tensile strength with an equivalent weight cannot be obtained. On the other hand, it is difficult to stably produce a base fabric larger than 0.036 N / main · dtex with the current technology.

  In the case of a base fabric obtained from a conventional polyamide multifilament, in order to obtain a base fabric having excellent tensile strength, the total fineness (D1, D2) in the vertical direction and the horizontal direction or the fabric density in the vertical direction and the horizontal direction. (S1, S2) must be increased, and the weight increases. Moreover, in order to obtain a base fabric excellent in lightness, the total fineness (D1, D2) in the vertical direction and the horizontal direction or the fabric density in the vertical direction and the horizontal direction (S1, S2) must be reduced. Tensile strength decreases. On the other hand, in the case of the airbag fabric according to the present invention, since the properties of the raw yarn are excellent, the tensile strength (T1, T2) in the warp direction and the transverse direction is equivalent to that of the base fabric obtained by the conventional multifilament. In this case, the total fineness (D1, D2) in the vertical direction and the horizontal direction or the fabric density (S1, S2) in the vertical direction and the horizontal direction can be reduced, and the values of the expressions 1 and 2 are increased. That is, it is possible to obtain a base fabric excellent in light weight while having a sufficient base fabric strength. In addition, when the total fineness (D1, D2) in the vertical direction and the horizontal direction or the fabric density (S1, S2) in the vertical direction and the horizontal direction is equivalent to the base fabric obtained from the conventional polyamide multifilament, Is superior, the tensile strength (T1, T2) in the vertical direction and the horizontal direction is increased, and the values of Equation 1 and Equation 2 are increased. That is, even if the weight is equal, a base fabric having excellent tensile strength can be obtained.

The basis weight of the airbag fabric of the present invention is preferably 220 g / m ² or less, more preferably 210 g / m ² or less, and even more preferably 200 g / m ² or less. Conventional airbag base fabrics are often used in excess of 220 g / m ^2. By using the airbag base fabric of the present invention, weight reduction and weight reduction of conventional airbags are achieved. be able to.

The airbag base fabric of the present invention can be suitably used for a portion requiring restraint and deployment such as a curtain airbag by covering at least one surface with a resin. Although the resin to coat | cover is not specifically limited, What has heat resistance, cold resistance, and a flame retardance is preferable, for example, a silicone resin, a polyamide-type resin, a polyurethane resin, a fluororesin etc. are mention | raise | lifted. In addition, an elastomer resin dispersed in water or a solvent may be used. The resin coating amount is preferably 5 to 40 g / m ² , so that air flow from the base fabric can be reduced, and more preferably. It is 5-25 g / m < ² >, More preferably, it is 10-20 g / m < ² >. The polyamide multifilament constituting the airbag fabric of the present invention has a total fineness of 200 to 500 dtex and a single fiber fineness of 1 to 4 dtex, so that the irregularities of the base fabric are small and the void ratio between single yarns is also small. This makes it possible to reduce the amount of resin required. By setting the discharge amount within this range, an increase in weight due to resin coating can be prevented, and the manufacturing cost can be suppressed.

  Further, it is preferable that the bending resistance based on ASTM D4032: 2002 is 20 N or less and the workability at the time of storing and folding the airbag is improved. More preferably, it is 15N or less, More preferably, it is 12N or less. If the bending resistance is 20 N or more, not only will the workability of the airbag be folded and folded worsen, but the folded bag will become bulky, and the airbag may not be stored unless the peripheral parts are enlarged. In some cases, lightness as an airbag module may be impaired.

  The thickness of the airbag fabric of the present invention is preferably 0.3 mm or less, more preferably 0.28 mm or less, and still more preferably 0.25 mm or less. By setting the thickness to 0.3 mm or less, not only the folded airbag can be made compact, but also the airbag module itself can be made compact, which can contribute to weight reduction of peripheral parts.

  The mechanical properties such as tensile strength, elongation, tear strength, slip resistance, and air permeability of the airbag fabric of the present invention are not significantly different from those disclosed in conventional airbag fabrics. The difference from the conventional fabric for airbags is the use of polyamide multifilament that maintains smaller single fiber fineness, greater polyamide multifilament strength, and the same polyamide multifilament elongation. In spite of the fact that weaving at a lower weaving density than conventional airbag fabrics or selecting polyamide fibers with low fineness, the mechanical properties of conventional airbag fabrics are maintained. . In addition, by selecting a polyamide multifilament having a low woven density or a low fineness, the lightness, thinness, and flexibility are remarkably improved.

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

  Polyamide multifilament is produced by the following method based on 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 2 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 with high strength and high elongation.

  It is preferable to apply water vapor to the spun yarn discharged from the die. In the melt spinning of polyamide multifilament, it is common to retain an inert gas, particularly water vapor, directly under the die, but it has been disclosed that the mechanical properties of industrial polyamide multifilament are particularly changed by water vapor. There is nothing. Surprisingly, in the production of high-strength polyamide multifilaments of single yarn 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. Investigated. 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 worsened, and the fluff and thread breakage will be increased. Therefore, the blowing pressure is preferably 100 to 400 Pa, more preferably 100 to 300 Pa. Preferably, it is 100-200 Pa. If the amount of water vapor is less than 100 Pa, the moisturizing effect on the die surface is impaired, and long-term productivity is impaired due to the accumulation of monomers. However, by supplying the minimum amount of water vapor at 100 Pa or more, turbulence directly under the die is suppressed, and the fineness It is preferable that spots do not easily occur. 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. Moreover, it is preferable to heat water vapor to 200-350 degreeC, It is more preferable that it is 275 degreeC or more as a minimum, and is 300 degrees C or less as an upper limit. The water vapor temperature may be adjusted by installing a heater in the water vapor channel. By setting the temperature of the water vapor within this range, the heat retaining property of the base is improved and the deformation of the yarn is moderated, whereby a high strength and high elongation polyamide multifilament can be obtained.

  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 that the atmospheric temperature in the cylinder is 250 to 350 ° C., more preferably 275 to 350 ° C. with a length of ˜100 mm, more preferably 50 to 80 mm. It is preferable to cool using an annular cooling device after heating to this atmospheric temperature. By using a slow cooling cylinder, it is possible to obtain a high-strength / high-strength polyamide multifilament by increasing the heat retaining property of the base and gradual deformation of the yarn, but the length of the slow cooling cylinder is within the above range. If it is, the thickness unevenness of the longitudinal direction of a polyamide multifilament will become 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. Although it can prevent deterioration, in that case, in order to obtain a polyamide multifilament with high strength and high elongation by keeping the base surface warm, with a certain length within 100 mm from the top of the annular cooling device, It is preferable to blow out hot air of 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 high-strength and high-strength single yarn fineness polyamide multifilament 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 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. 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 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 multifilament with a total fineness of 200 to 500 dtex and a single fiber fineness of 2 to 4 dtex using a conventional horizontal blowout cooling facility, the yarn swinging at the spinning section becomes too intense, and the cooling wind speed is reduced. In addition, it is necessary to suppress the contact between the single fibers even if the cooling air speed is decreased at 1 to 2 dtex, whereas in the above-described method of the present invention, the cooling before the yarn solidification is performed. Even if the wind speed is reduced, the distance between the cooling air and the spun yarn is close, so there is no insufficient cooling, and air collides to form a downdraft, increasing the horizontal velocity component of the cooling air. It is presumed that the yarn can be produced while suppressing the yarn swinging.

  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.

  Further, the spinning speed defined by the rotational speed of the take-up roll is preferably 500 to 1000 m / min, more preferably 600 to 800 m / min. When the spinning speed is 500 m / min or more, the final production speed is sufficient, and polyamide multifilaments 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. Moreover, it is preferable that the extending | stretching speed represented by the maximum speed of an extending | stretching roll is 2800 m / min or more, More preferably, it is 3000 m / min or more.

  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%. Moreover, in order to obtain a high-strength polyamide multifilament, it is preferable to employ a high draw ratio. If the spinning speed is within the above-described range, it may be drawn at 4.5 to 5.5 times.

  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.

  The number of fluffs of the obtained polyamide multifilament is preferably 20/10 million m or less, more preferably 10/10 million m or less, and further preferably 5/10 million m or less. Within this range, yarn breakage due to fluff generation can be suppressed, the number of stops during weaving can be suppressed, and productivity can be improved.

  Moreover, the single yarn cross-sectional shape of the polyamide multifilament of the present invention is not particularly limited, and a circular shape, a non-circular shape such as a Y shape, a V shape, a flat shape, etc., and a hollow portion can also be used. Is preferably circular.

Thus, a polyamide multifilament suitable for an airbag having a total fineness of 200 to 500 dtex and a single fiber fineness of 1 to 4 dtex, which could not be produced by the conventionally proposed method, has a strength of 9 cN / dtex or more, an elongation of 20% or more, and a fineness. The spots are 1.2% or less, and it is possible to obtain excellent strength / elongation and fluff quality at low cost. That is, by using an annular cooling device, it becomes possible to produce a polyamide multifilament having a total fineness of 200 to 500 dtex and a single fiber fineness of 1 to 4 dtex, and the presence / absence of water vapor / water vapor temperature / slow cooling cylinder (heating cylinder) ) temperature can achieve high strength and high elongation by optimizing the, also has high strength and high elongation than by optimizing the V _U can be achieved. Furthermore, by optimizing the presence or absence of water vapor, the amount of water vapor, the length of the slow cooling cylinder (heating cylinder), and the differential pressure between the cooling cylinder and the atmospheric pressure, fineness spots are reduced, and the generation of fluff is suppressed even during high magnification drawing. There is an effect to.

  Next, the airbag fabric of the present invention is manufactured by the following method.

  First, warp yarn having the above-mentioned raw material, total fineness, and single fiber fineness is warped and applied to a loom, and a 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.

  In weaving, when used as a non-coated airbag base fabric without applying a resin, the warp yarn tension is preferably adjusted to 120 to 230 cN / line, more preferably 150 to 200 cN / line. By adjusting the warp yarn tension within such a range, the gap between the single fibers in the yarn bundle of the multifilament yarn constituting the base fabric can be reduced, and hence the air flow rate can be reduced. In addition, the warp yarn subjected to the above-mentioned tension pushes and bends the weft yarn after driving the weft yarn, thereby increasing the tissue binding force of the base fabric in the weft direction and improving the anti-displacement property of the base fabric. As a result, air leakage due to misalignment of the sewing portion when forming the bag can be suppressed. When the warp yarn tension is 75 cN / string or more, the contact area of the warp yarn and the weft yarn in the base fabric can be increased, and the sliding resistance is improved. Moreover, since the effect of decreasing the space | gap between single fibers becomes large, it becomes a low air permeable base fabric, and is preferable. Moreover, if it is 230 cN / piece or less, a warp thread will not fluff and weaving will become favorable. Moreover, when using as a base fabric for a coated airbag in which a resin is applied on at least one side, it is preferable that the warp yarn tension is 50 to 100 cN / line. By adjusting the warp yarn tension within this range, the load on the loom and warp yarn can be reduced, so the strength of the polyamide multifilament can be fully utilized, reducing the weaving density. It becomes possible to do.

  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 can be determined, for example, by measuring the tension applied to one warp yarn with a tension measuring instrument between the warp beam and the back roller while the loom is running. Can be confirmed.

  Further, it is preferable to make a difference of 10 to 90% between the tension of the upper thread and the tension of the lower thread in the warp thread opening. By doing so, the above-mentioned warp yarn bending structure is promoted, the warp yarn and the weft yarn are strongly pressed against each other, the friction resistance force between the yarn and the yarn is increased, and the slipping resistance force can be improved.

  As a method of making a difference between the tension of the upper thread and the tension of the lower thread at the warp thread opening, for example, by setting the back roller at a higher position, the upper thread traveling line length and the lower thread traveling line length There is a way to make a difference. For example, by placing a guide roll between the back roller and the reed and shifting the opening fulcrum upward or downward from the warp line with this guide roll, the running line length of one yarn is longer than the other when opening. As a result, the tension increases and it becomes possible to make a difference between the tension of the upper thread and the tension of the lower thread. As the installation position of the guide roll, it is preferable to arrange the guide roll at a position of 20 to 50% from the back roller side with respect to the interval between the back roller and the wrinkle. The position of the opening fulcrum is preferably 5 cm or more away from the warp line.

  In addition, as another method for making a difference between the tension of the upper thread and the tension of the lower thread, for example, a cam drive system is adopted for the opening device, and the dwell angle on one side of the upper thread / lower thread is 100 degrees or more than the other. There is also a way to take large. Increasing the dwell angle increases the tension.

  As a loom temple, a bar temple is preferably used when used as a non-coated airbag base fabric. When the bar temple is used, it can be beaten while gripping the entire front of the weave, so that the gap between the synthetic fiber filaments can be reduced, and as a result, the low air flow rate and the resistance to misalignment are improved. . Further, when used as a base fabric for a coated airbag in which a resin is applied on at least one surface, a bar temple or a ring temple may be used. Since the ring temple grips only the end of the ear, it is difficult to achieve a high woven density, but it can be applied to a coated airbag base fabric used at a relatively low woven density.

  An important mass productivity evaluation index in the weaving process is the number of times the loom stops. There are various factors in the stop, but in many cases, it is often caused by fluff of polyamide multifilament. When there is fluff, when it passes through the heald or the heel, the fluff grows, entangles with the yarn breakage or adjacent multifilament, and stops. This phenomenon is more likely to cause stopping as the weaving density is higher and the weaving tension is higher. Naturally, if the number of stops due to fluff is 0 times / 1000 m, there is no problem, but it is difficult to suppress to 0 times / 1000 m due to the characteristics of the polyamide multifilament. If the number of stops due to fluff is 4.0 times / 1,000 m or less, it is considered that production efficiency and generation of non-standard products are not significantly affected, preferably 2.0 times / 1,000 m or less, and more preferably Is 1.0 times / 1000 m.

  Next, when the weaving process is finished, processing such as scouring and heat setting is performed as necessary. When used for curtain airbags, side airbags, and knee airbags that require a particularly small air flow rate, if necessary, a resin can be applied to the surface of the base fabric, or a film can be applied to form a coated fabric. Good.

  The airbag fabric of the present invention has improved fabric strength, sliding resistance, low air permeability, and compactness when storing airbags that could not be improved simultaneously with these characteristics. In addition to obtaining an airbag base fabric with improved characteristics in a well-balanced manner, for example, the storage base is the same as that of the conventional product, and the airbag base fabric has significantly improved breathability and anti-displacement, or It is also possible to obtain an air bag base fabric which has the same resistance to misalignment and a low base fabric density, that is, an inexpensive and excellent storage property due to a decrease in the number of fibers used. The airbag fabric of the present invention can be suitably used for any airbag such as a driver seat, a passenger seat, a rear seat, and a side airbag.

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

  (1) Sulfuric acid relative viscosity: 2.5 g of a sample was dissolved in 25 cc of 96% concentrated sulfuric acid and measured using an Ostwald viscometer at a constant temperature in a thermostatic bath at 25 ° C.

  (2) 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.

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

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

  (5) 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.

(6) Boiling water shrinkage ratio: Sampling the raw yarn in a crushed shape, adjusting it 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 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 (%)

  (7) 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.

(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, 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.

  (9) Number of fuzz sensors: The number of fuzz on-line was measured with a shock sensor (SC) type fuzz counter in the yarn making process.

  (10) Fabric thickness: According to JIS L 1096: 1999 8.5, using a thickness measuring machine at 5 different points of the sample, the pressure was kept at 23.5 kPa and waited for 10 seconds to settle the thickness. Later, the thickness was measured and the average value was calculated.

  (11) Fabric 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.

  (12) Cover factor: The total fineness of the warp and weft yarns is Dw (dtex) and Df (dtex), and the base fabric density of the warp and weft yarns is Nw (line / 2.54 cm) and Nf (line / line), respectively. 2.54 cm) and calculated by the following method.

Warp Yarn Cover Factor: CFw = (Dw × 0.9) ^1/2 × Nw
Weft cover factor: CFf = (Df × 0.9) ^1/2 × Nf
Total cover factor: CF = CFw + CFf

(13) Fabric weight: In accordance with JIS L 1096: 1999 8.4.2, three test pieces of 20 cm × 20 cm were sampled, each mass (g) was weighed, and the average value was the mass per 1 m ² ( g / m ² ).

  (14) Tensile strength: JIS K 6404: 1999 3 6. In accordance with test method B (strip method), for each of the warp direction and the horizontal direction of the woven fabric, five test pieces are collected, the yarn is removed from both sides of the width to obtain a width of 30 mm, and a gripping interval is obtained with a tensile tester. The test piece was pulled at 150 mm and a pulling speed of 200 mm / min until the maximum load until cutting was measured, and the average value was calculated for each of the vertical and horizontal directions.

(15) Elongation at break: JIS K 6404: 1999 3 6. In accordance with test method B (strip method), for each of the warp direction and the horizontal direction of the woven fabric, five test pieces were sampled, the thread was removed from both sides of the width to a width of 30 mm, and 100 mm in the center of these test pieces. Attach the marked line of the interval, pull it with a tensile tester at a gripping interval of 150 mm and a tensile speed of 200 mm / min until the test piece is cut, read the distance between the marked lines when cutting, and use the following formula to The degree was calculated, and the average value was calculated for each of the vertical and horizontal directions.
E = [(L-100) / 100] × 100
E: Elongation at break (%),
L: Distance (mm) between marked lines at the time of cutting.

(16) Formulas 1 and 2: Formulas 1 and 2 were calculated by dividing the vertical and horizontal tensile strengths by the total fineness and weave density of the vertical and horizontal yarns.
Formula 1 = T1 (N / cm) / D1 (dtex) / S1 (line / 2.54 cm)
Formula 2 = T2 (N / cm) / D2 (dtex) / S2 (line / 2.54 cm)

  (17) Tear strength: JIS K 6404: 1999 4 6. In accordance with test method B (single tongue method), test pieces with a long side of 200 mm and a short side of 76 mm were taken on each of the vertical and horizontal sides of the fabric, and five test pieces were collected respectively. A 75 mm incision was made at a right angle, and the specimen was torn with a tensile 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.

  (18) Bending softness: In accordance with ASTM D 4032-94: 2002, test pieces having a long side of 204 mm and a short side of 102 mm were sampled and measured on each of the warp and side of the woven fabric. About the obtained maximum load (N), the average value was calculated for each of the vertical direction and the horizontal direction.

  (19) 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.

(20) Sliding resistance force In accordance with ASTM D6479-02, a mark was placed at a position 5 mm from the end of the base fabric sample, and a needle was accurately inserted into the position and measured.

  The slip resistance force in the warp direction is measured by measuring the maximum load when a pin is stabbed along the weft thread and the weft thread is moved in the warp direction with that pin. The maximum load when the pin is stabbed along and the warp yarn is moved in the horizontal direction with the pin is measured.

[Examples 1 to 10, Reference Example 4]
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 are supplied to an extruder, and the discharge amount is adjusted so as to obtain two yarns having a total fineness of Tables 1 and 2 by a metering pump and arranged in a spinneret, and melt spinning at 295 ° C. did. Each spinneret has a number capable of obtaining two yarns having the number of single fibers shown in Tables 1 and 2, that is, discharge holes twice the number of single fibers shown in Tables 1 and 2 have a diameter of 0.22 mm. The diameter when the outermost discharge hole groups are concentrically connected to each other is 3 mm smaller than the inner diameter of the slow cooling cylinder (heating cylinder) and the cooling cylinder. A circular steam blowing device with a heater is installed 50 mm below the yarn discharge surface, and there are 12 holes with a diameter of 2 mm and a depth of 4 mm at regular intervals. The temperatures shown in Tables 1 and 2 are used. Heated water vapor was blown off at an angle of 60 ° C. at the pressures shown in Tables 1 and 2. Further, a slow cooling cylinder having the length shown in Tables 1 and 2 heated to 350 ° C. is provided immediately below the base, and a cylindrical annular cooling device having the cooling air blowing lengths shown in Tables 1 and 2 is used. The cooling air was pressurized and blown so that the differential pressure between the inside of the cooling cylinder and the atmospheric pressure became the values shown in Tables 1 and 2, 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 the drawing speed) is set to a constant speed of 3200 m / min, and the overall drawing ratios represented by the take-off speed and the drawing speed ratio are shown in Tables 1 and 2. The rotation speed of the take-up roller was adjusted so as to be a value.

  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, relaxation heat treatment was performed between the second stretching roller and the relaxation roller at the relaxation rate shown in Table 1 and Table 2, and 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.

  The characteristics of the obtained nylon 66 fiber are shown in Tables 1 and 2.

A shock sensor type fluff counter is installed between the relaxation roller and the entanglement imparting device, and the number of fluff per 10 ⁷ m is also shown in Table 1 and Table 2.

  In Examples 1 to 10, the polyamide multi has a single fiber fineness of 1 to 4 dtex in the range of a total fineness of 200 to 500 dtex, a strength of 9.0 cN / dtex or more, and an elongation of 20% or more. A filament could be obtained, and the number of fluffs of the shock sensor was 20/10 million m or less, and the fluff quality was good.

[Comparative Examples 1-4, Reference Examples 1-3]
Using a tip having a relative viscosity of sulfuric acid shown in Table 2, the discharge amount was adjusted by a metering pump so as to obtain two yarns having a total fineness of Table 2, and arranged in the spinneret. The number of yarns that can be obtained by two yarns, that is, the number of discharge holes twice the number of single fibers shown in Table 2, and the minimum value of the discharge hole interval is 7.5 mm and arranged in a staggered arrangement Was used. By uniformly blowing a cooling air of 30 m / min from a horizontal blow cooling device having a length of 1500 mm, two yarns can be obtained at the drawing speed shown in Table 2. Nylon 66 under the conditions shown in Table 2 This was carried out in the same manner as in Example 1 except that production of the fiber was attempted. Table 2 shows the fiber properties and fuzz results of the obtained nylon 66 fibers.

  Although Comparative Example 1 had a low draw ratio, it had a larger number of fuzz sensors and a toughness than that of Example 1.

  In Comparative Example 2, a single yarn collision occurred in the cooling and solidifying process, and the number of shock sensor fluffs was 150 tens of millions of meters per million compared to Example 6 despite the fact that the draw ratio was greatly reduced. there were.

  In Comparative Example 3, a horizontal draw cooling device was used to obtain a high draw ratio, toughness was reduced, and the number of fuzz sensors was large.

  Since Comparative Example 4 uses a low-viscosity chip, the toughness is lowered, the number of fluffs of the shock sensor is as large as 300 pieces / 10 million meters, and there are many yarn breaks. It wasn't.

[Comparative Example 5]
The same procedure as in Comparative Example 1 was performed except that the stretching speed was 2000 m / min and the three-stage stretching method was used.

  Although high-strength fibers can be obtained by reducing the drawing speed by three-stage drawing, the number of fluffs of the shock sensor was as large as 200 / 10,000,000 m, and the fluff quality was not woven.

[Example 11]
The nylon 66 fiber of Example 5 was used as warp and weft, and the raw machine density of the warp yarn was 57.5 / 2.54 cm and the raw machine density of the warp yarn was 58 / 2.54 cm with no twist. The fabric was woven.

  A water jet loom is used for the loom, a bar temple is installed between the hammering portion and the friction roller to grip the base fabric, and between the back roller and the scissors, at a position 40 cm from the back roller, A guide roll was attached so as to lift the 7 cm warp yarn from the warp line.

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 150 cN / line, the upper thread tension when the loom was stopped was adjusted to 120 cN / line, and the lower thread tension was adjusted to 169 cN / line, and the loom rotation speed was 500 rpm. did.

  Next, this base fabric was scoured with an open soap type scourer at a scouring bath temperature of 80 ° C. and a washing bath temperature of 40 ° C., followed by drying at 120 ° C. Heat setting for 1 minute was performed at 120 ° C. under the dimensional regulation of 0%.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. In addition, the number of stops due to fluff during weaving was 2.5 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Example 12]
The nylon 66 fiber of Example 7 was used as warp and weft, and the raw machine density of the warp yarn was 69.0 pieces / 2.54 cm, and the raw machine density of the weft yarn was 69.0 pieces / 2.54 cm with no twist. Weaving the base fabric.

  The loom uses a water jet loom, a bar temple is installed between the hammering section and the friction roller to grip the base fabric, and no guide roll is arranged between the back roller and the scissors. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 120 cN / line, the upper thread tension when the loom was stopped was adjusted to 120 cN / line, and the lower thread tension was adjusted to 120 cN / line, and the loom rotation speed was 500 rpm. did.

  Subsequently, this base fabric was subjected to a heat setting process at 160 ° C. for 1 minute using a pin tenter dryer under the dimensional regulation with a width insertion rate of 0% and an overfeed rate of 0%.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. Further, the number of stops due to fluff during weaving was 2.0 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Example 13]
The nylon 66 fiber of Example 1 was used as a warp and a weft, and the raw machine density of the warp yarn was 49.0 pieces / 2.54 cm, and the raw machine density of the weft yarn was 49.0 pieces / 2.54 cm with no twist. Weaving the base fabric.

  The loom uses a water jet loom, a bar temple is installed between the hammering section and the friction roller to grip the base fabric, and no guide roll is arranged between the back roller and the scissors. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 180 cN / line, the upper thread tension when the loom was stopped was adjusted to 180 cN / line, and the lower thread tension was adjusted to 180 cN / line, and the loom rotation speed was 500 rpm. did.

  Next, this base fabric was scoured with an open soap type scourer at a scouring bath temperature of 80 ° C. and a washing bath temperature of 40 ° C., followed by drying at 120 ° C. Heat setting for 1 minute was performed at 120 ° C. under the dimensional regulation of 0%.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. In addition, the number of stops due to fluff during weaving was 4.0 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Example 14]
Using the nylon 66 fiber of Example 2 as warp yarn and weft yarn, the raw machine density of the warp yarn is 49.0 yarns / 2.54 cm, and the raw machinery density of the warp yarn is 49.0 yarns / 2.54 cm with no twist. Weaving the base fabric.

  The loom uses a water jet loom, a bar temple is installed between the hammering section and the friction roller to grip the base fabric, and no guide roll is arranged between the back roller and the scissors. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 180 cN / line, the upper thread tension when the loom was stopped was adjusted to 180 cN / line, and the lower thread tension was adjusted to 180 cN / line, and the loom rotation speed was 500 rpm. did.

  Next, this base fabric was scoured with an open soap type scourer at a scouring bath temperature of 80 ° C. and a washing bath temperature of 40 ° C., followed by drying at 120 ° C. Heat setting for 1 minute was performed at 120 ° C. under the dimensional regulation of 0%.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. Further, the number of stops due to fluff during weaving was 2.0 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Example 15]
Nylon 66 fiber of Example 3 was used as warp and weft, and the raw machine density of the warp yarn was 54.5 pieces / 2.54 cm, and the raw machine density of the weft yarn was 55.5 pieces / 2.54 cm with no twist. Weaving the base fabric.

The loom uses a water jet loom, a bar temple is installed between the hammering section and the friction roller to grip the base fabric, and no guide roll is arranged between the back roller and the scissors. .
As the weaving conditions, the warp yarn tension during weaving was adjusted to 170 cN / line, the upper thread tension when the loom was stopped was adjusted to 170 cN / line, and the lower thread tension was adjusted to 170 cN / line, and the loom rotation speed was 500 rpm. did.

  Next, this base fabric was scoured with an open soap type scourer at a scouring bath temperature of 65 ° C. and a washing bath temperature of 40 ° C., followed by drying at 120 ° C. Heat setting for 1 minute was performed at 120 ° C. under the dimensional regulation of 0%.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. In addition, the number of stops due to fluff during weaving was 1.4 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Example 16]
The nylon 66 fiber of Example 1 was used as warp and weft, and the raw machine density of the warp yarn was 45.0 pieces / 2.54 cm and the raw machine density of the warp yarn was 47.0 pieces / 2.54 cm with no twist. Weaving the base fabric.

Use a water jet loom for the loom, install a ring temple between the hammering section and the friction roller to grip the ear of the base fabric, and do not place a guide roll between the back roller and the scissors The configuration.
As the weaving conditions, the warp yarn tension during weaving was adjusted to 100 cN / line, the upper thread tension when the loom was stopped was adjusted to 100 cN / line, and the lower thread tension was adjusted to 100 cN / line, and the loom rotation speed was 600 rpm. did.

  Next, after drying this base fabric at a drying temperature of 85 ° C., a refining and setting are performed, and a floating knife method using a methyl vinyl silicone resin liquid having a viscosity of 16 Pa · s and a knife having a thickness of 4 mm is used. The coating was performed at a coating tension of 90 kgf / m, a knife-woven fabric contact pressure of 20 kgf / m, and a speed of 20 m / min, followed by vulcanization at 190 ° C. for 1 minute.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. In particular, the coating amount was successfully reduced despite the coating amount being the same as the conventional coating amount. Moreover, the number of stops due to fluff during weaving was 3.0 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Example 17]
Nylon 66 fiber of Example 8 was used as warp and weft, and the raw machine density of warp yarn was 49.0 / 2.54 cm and the raw machine density of weft yarn was 51.0 / 2.54 cm with no twist. Weaving the base fabric.

Use a water jet loom for the loom, install a ring temple between the hammering section and the friction roller to grip the ear of the base fabric, and do not place a guide roll between the back roller and the scissors The configuration.
As the weaving conditions, the warp yarn tension during weaving was adjusted to 100 cN / line, the upper thread tension when the loom was stopped was adjusted to 100 cN / line, and the lower thread tension was adjusted to 100 cN / line, and the loom rotation speed was 600 rpm. did.

  Next, after drying this base fabric at a drying temperature of 85 ° C., a refining and setting are performed, and a floating knife method using a methyl vinyl silicone resin liquid having a viscosity of 16 Pa · s and a knife having a thickness of 4 mm is used. The coating was performed at a coating tension of 90 kgf / m, a knife-woven fabric contact pressure of 20 kgf / m, and a speed of 20 m / min, followed by vulcanization at 190 ° C. for 1 minute.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. In particular, the coating amount was successfully reduced despite the coating amount being the same as the conventional coating amount. Moreover, the number of stops due to fluff during weaving was 3.0 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Example 18]
The nylon 66 fiber of Example 7 was used as warp and weft, and the raw machine density of the warp yarn was 67.0 pieces / 2.54 cm and the raw machine density of the weft yarn was 69.0 pieces / 2.54 cm with no twist. Weaving the base fabric.
A water jet loom is used for the loom, a ring temple is installed between the hammering section and the friction roller to grip the base fabric, and no guide roll is arranged between the back roller and the scissors. .

  As the weaving conditions, the warp yarn tension during weaving was adjusted to 80 cN / line, the upper thread tension when the loom was stopped was adjusted to 80 cN / line, and the lower thread tension was adjusted to 80 cN / line, and the loom rotation speed was 600 rpm. did.

  Next, after drying this base fabric at a drying temperature of 85 ° C., a refining and setting are performed, and a floating knife method using a methyl vinyl silicone resin liquid having a viscosity of 16 Pa · s and a knife having a thickness of 4 mm is used. The coating was performed at a coating tension of 90 kgf / m, a knife-woven fabric contact pressure of 20 kgf / m, and a speed of 20 m / min, followed by vulcanization at 190 ° C. for 1 minute.

  Table 3 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric was excellent in lightness, thinness, and flexibility while having mechanical properties equivalent to those of a conventional airbag fabric. In particular, the coating amount was successfully reduced despite the coating amount being the same as the conventional coating amount. In addition, the number of stops due to fluff during weaving was 1.0 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Comparative Example 6]
An air bag base fabric was produced in the same manner as in Example 11 except that the nylon 66 fibers of Reference Example 2 were used as warp and weft yarns and the conditions shown in Table 4 were used.

  Table 4 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric had the same mechanical properties as the fabric of Example 8, but was inferior in lightness, thinness, and flexibility. The number of stops due to fluff during weaving was 1.2 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Comparative Example 7]
A base fabric for an airbag was manufactured in the same manner as in Example 11 except that the nylon 66 fiber of Comparative Example 3 was used as warp and weft and the conditions shown in Table 4 were used.

  The characteristics of the obtained airbag fabric are shown in Table 2. The obtained airbag base fabric had the same lightness, thinness and flexibility as the base fabric of Example 8, but the elongation was small and the airbag base fabric had toughness. And there was a risk of breaking when the airbag was deployed. In addition, the number of stops due to fluff during weaving was 19.2 times / 1000 m, which not only significantly reduced the production efficiency, but also had many defects and became a non-standard product that could not be applied to airbag fabrics.

[Comparative Example 8]
Implementation was performed except that the nylon 66 fiber of Comparative Example 2 was used as warp and weft, and the warp density was 52.5 / 2.54 cm, and the weft density was 54.5 / 2.54 cm. An airbag base fabric was produced in the same manner as in Example 14.

  Table 4 shows the characteristics of the obtained airbag fabric. The obtained airbag base fabric had a lower tensile strength than the base fabric of Example 14, and was inferior in all of lightness, thinness, and flexibility. In addition, the number of stops due to fluff during weaving was 38.5 times / 1000 m, which not only significantly deteriorated production efficiency, but also resulted in non-standard products that could not be applied to airbag fabrics.

[Comparative Example 9]
Implemented except that the nylon 66 fiber of Reference Example 3 was used as warp and weft, and the warp density was 54.5 / 2.54 cm, and the weft density was 54.0 / 2.54 cm. An airbag base fabric was produced in the same manner as in Example 14.

  Table 4 shows the characteristics of the obtained airbag fabric. The obtained air bag base fabric had the same mechanical characteristics as the base fabric of Example 14 except for the air permeability, but was inferior in lightness, thinness, and flexibility. . The number of stops due to fluff during weaving was 3.5 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Comparative Example 10]
Implemented except that the nylon 66 fiber of Reference Example 1 was used as warp and weft, and the warp density was 54.5 / 2.54 cm, and the weft density was 54.0 / 2.54 cm. An airbag base fabric was produced in the same manner as in Example 14.

  Table 4 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric had the same mechanical properties as the fabric of Example 14, but was inferior in lightness, thinness, and flexibility. The number of stops due to fluff during weaving was 0.8 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Comparative Example 11]
Implemented except that the nylon 66 fiber of Reference Example 3 was used as warp and weft, and the warp density was 49.5 / 2.54 cm and the weft density was 51.0 / 2.54 cm. An airbag base fabric was produced in the same manner as in Example 16.

  Table 4 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric had the same mechanical properties as the fabric of Example 16, but was inferior in lightness, thinness and flexibility. The number of stops due to fluff during weaving was 3.1 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Comparative Example 12]
Implemented except that Nylon 66 fiber of Reference Example 1 was used as warp and weft, and the warp density was 49.5 / 2.54 cm and the weft density was 51.0 / 2.54 cm An airbag base fabric was produced in the same manner as in Example 17.

  Table 4 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric had the same mechanical properties as the fabric of Example 17, but was inferior in lightness, thinness and flexibility. The number of stops due to fluff during weaving was 0.4 times / 1,000 m, which was a weaving situation that could withstand mass production.

[Comparative Example 13]
Implemented except that Nylon 66 fiber of Reference Example 2 was used as warp and weft, and the warp density was 57.0 / 2.54 cm, and the weft density was 59.0 / 2.54 cm. An airbag base fabric was produced in the same manner as in Example 16.

  Table 4 shows the characteristics of the obtained airbag fabric. The obtained airbag fabric had the same mechanical properties as the fabric of Example 16, but was inferior in lightness, thinness and flexibility. The number of stops due to fluff during weaving was 0.5 times / 1,000 m, which was a weaving situation that could withstand mass production.

  The airbag fabric according to the present invention is composed of airbag yarns that combine unprecedented single yarn fineness and high strength, and is excellent in flexibility, thinness, and lightweight. It is about cloth. The airbag fabric of the present invention can be suitably used particularly for a driver's seat, a passenger's seat, a side airbag for side collision, and the like, but its application range is not limited thereto.

Claims (7)

An airbag base fabric composed of polyamide multifilament, wherein the cover factor (CF) of the airbag base fabric is in the range of 1600 to 2300, and Formulas 1 and 2 are 0.030 to 0.036 N The total fineness of the polyamide multifilament is 200 to 500 dtex, the single fiber fineness is 1 to 4 dtex, the strength is 9.0 cN / dtex or more, the elongation is 20% or more, and the polyamide multifilament A base fabric for airbags, wherein 95% by weight or more of the polyamide constituting the filament is a hexamethylene adipamide component.
CF = √ (D1 (dtex) × 0.9) × S1 ( the /2.54cm)+√ (D2 (dtex) × 0.9 ) × S2 ( present per 2.54 cm)
Formula 1 = T1 (N / cm) / D1 (dtex) / S1 (line / 2.54 cm)
Formula 2 = T2 (N / cm) / D2 (dtex) / S2 (line / 2.54 cm)
(here,
T1: Tensile strength in the vertical direction (N / cm)
T2: Tensile strength in the horizontal direction (N / cm)
D1: Total fineness in the vertical direction (dtex)
D2: Total fineness in the horizontal direction (dtex)
S1: Textile density in the vertical direction (main / 2.54cm)
S2: Woven fabric density in a horizontal direction (book / 2.54cm)
It is. ) The base fabric for an air bag according to claim 1, wherein the total fineness of the multifilament is within a range of 400 to 500 dtex. The base fabric for an air bag according to claim 1 or 2, wherein the single filament fineness of the multifilament is in the range of 1 to 2 dtex. The airbag base fabric according to any one of claims 1 to 3, wherein the cover factor is in the range of 1600 to 2200, and at least one surface is coated with a resin. Base fabric for an air bag according to claim 4, wherein the吐工amount of resin at least is coated on one side is in the range of 5 to 40 g / m ^2. The base fabric for an air bag according to any one of claims 1 to 5, wherein the bending resistance based on ASTM D4032: 2002 is 20 N or less. Thickness is 0.3 mm or less, The base fabric for airbags of any one of Claims 1-6 characterized by the above-mentioned.