WO2018062132A1 - Non-coated fabric for airbag and airbag using same - Google Patents

Abstract

[Problem] To provide a non-coated fabric for an airbag that has less air leakage than non-coated fabrics for airbags developed by conventional technology and that is usable in locations where use was not possible except for conventional coated fabrics for airbags, and an airbag using the same. [Solution] The non-coated fabric for an airbag includes single fibers having a substantially triangular cross-sectional shape and atypism of 1.3 – 2.2, and has a cover factor (CF) of 2050 – 2600 and a ventilation rate of 0.25 L/cm²/min or less under a pressure differential of 20 kPa.

Description

Non-coated fabric for airbag and airbag using the same

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

In recent years, as a result of heightened safety awareness and changes in safety regulations, in addition to safety measures assuming frontal accidents such as driver airbags and passenger airbags in automobiles, side accidents are also assumed. The adoption of curtain airbags and side airbags is increasing.

比 べ Compared to the frontal crash, the side impact accident requires a shorter distance between the side of the vehicle body that receives the impact and the occupant, and it is necessary to deploy the airbag at a higher speed, and it is necessary to minimize air leakage during deployment. For this reason, a coating fabric with low air permeability is generally used for curtain airbags and side airbags.

However, as safety awareness increases, the number of parts where airbags are mounted increases, while there are demands for improving fuel consumption by reducing the weight of the body and for reducing the cost of assembly equipment to reduce the body price. Therefore, as a woven fabric used for an airbag (hereinafter sometimes referred to as “airbag woven fabric”), it is desired to replace a heavy coated fabric with a high cost with a non-coated fabric.

When considering the air permeability as an airbag, it is necessary to consider the air permeability from the airbag fabric that is the airbag body and the air permeability from the sewing portion that stitches the airbag fabric together. In order to keep the air permeability of the main body portion and the sewing portion as low as possible with a non-coated fabric, it is preferable to use a woven fabric with high density.
The following techniques have been disclosed in the past as techniques for reducing the air permeability of an airbag.

Patent Document 1 discloses a technique in which two types of polyester fibers having different single yarn fineness are mixed to reduce the gap between the single yarns to reduce air permeability.

Patent Document 2 discloses a technique in which weaving is performed using a cam-driven loom so that a denser fabric is woven to reduce air permeability.

Patent Document 3 discloses a technology for providing a fabric for an airbag having high slip resistance and low breathability by weaving at a high density using a single yarn fiber having a flat single yarn cross-sectional shape. Is disclosed.

JP-A-8-325888 JP 2000-328388 A JP 2006-16707 A

As described above, various methods for reducing the air permeability of a non-coated fabric for an air bag have been studied, but no non-coated fabric for an air bag has been developed that has low air permeability so that a conventional coated fabric can be substituted.

The present invention has been made with a focus on lowering the air permeability and increasing the density of non-coated fabrics for airbags, and its purpose is less air leakage than non-coated fabrics for airbags developed in the prior art. An object of the present invention is to provide a non-coating fabric for an airbag that can be used even in a portion that could not be used unless the coating fabric for an airbag is used conventionally, and an airbag using the same.

As a result of intensive studies to solve the above problems, the present inventors have succeeded in weaving a non-coating fabric for airbags containing fibers of a substantially triangular cross section having a specific degree of irregularity in the woven yarn, The present invention was completed by discovering that the air permeability is lower than that of the conventional non-coated fabric and the sliding resistance value is high. The present invention has the following configuration.
(1) Including a single yarn fiber having a substantially triangular cross-section and an irregularity of 1.3 to 2.2, a cover factor (CF) of 2050 to 2600, and an air permeability under a 20 kPa differential pressure of 0. Non-coating fabric for airbag which is 25 L / cm ² / min or less.
(2) The non-coating fabric for an air bag according to (1), wherein the sliding resistance defined by ASTM D 6479 is 700N or more and 1200N or less as an average value in the vertical direction and the horizontal direction.
(3) The non-coated fabric for an air bag according to (1) or (2), wherein the air permeability under a differential pressure of 20 kPa after folding of the fabric measured by the following method is 0.30 L / cm ² / min or less. .
[Air permeability under 20 kPa differential pressure after folding fabric]
A test piece of 20 cm square is cut out from an arbitrary place excluding the range of 30 cm from both ends in the width direction of the woven fabric, the test piece is folded in half along the fiber axis direction (a), and then in the fiber axis direction (a). Fold in half along the orthogonal fiber axis direction (b), fold again in half along the fiber axis direction (a), and half in the fiber axis direction (b) orthogonal to the fiber axis direction (a) Fold it into 5cm squares. A load of 50 N is applied to the entire surface of the folded test piece for 1 minute, and then the test piece is left for 1 minute in a state where it is spread to 20 cm square. The air permeability under a differential pressure of 20 kPa is measured using a circle having a diameter of 10 cm centering on the intersection of the first fold and the second fold as a measurement site.
(4) The change rate of the air permeability under a 20 kPa differential pressure after folding of the woven fabric measured by the method described in (2) with respect to the air permeability under a 20 kPa differential pressure of the woven fabric is 150% or less (1) A non-coated fabric for an airbag according to any one of (3) to (3).
(5) Any of (1) to (4), wherein the total fineness of the fibers constituting the woven fabric is 100 dtex or more and 600 dtex or less, the number of filaments is 40 or more and 200 or less, and the single yarn fineness is 1 dtex or more and 8 dtex or less. The non-coating fabric for airbags according to crab.
(6) The boiling water shrinkage rate of the yarn defined in 8.1 of JIS L1013 (1999) is 7% or more and 12% or less, and the yarn is made of nylon fiber (1) to (5) The non-coating fabric for airbags as described.
(7) An airbag using the non-coated fabric for airbags according to any one of (1) to (6).
(8) Air in which the cross-sectional shape uses atypical fibers other than the round cross-sectional shape, the weft cover factor setting during weaving is 1040 or more, and the amount of protrusion before weaving on the nozzle side is 320 ° or more and 350 ° or less A method for producing a non-coated fabric for bags.
(9) The method for producing a non-coated fabric for an air bag according to (8), wherein the cross-sectional shape is a polygonal shape and the number of vertices is 3 or more and 6 or less.
(10) The method for producing a non-coated fabric for an airbag according to (8) or (9), wherein the cross-sectional shape is a polygonal shape and the number of vertices is three.

The non-coating woven fabric for airbags of the present invention includes substantially triangular cross-section fibers having a specific degree of irregularity in the woven yarn, so that it can be woven at a high density, has a lower air permeability than conventional non-coated woven fabrics, and slip resistance. High value can be exhibited.

It is a figure which shows the nozzle which has an atypical cross section, and how to obtain | require the atypical degree. It is a cross-sectional schematic diagram which shows an example of the preferable cross-sectional shape of a single yarn fiber, and how to obtain | require the atypical degree of the cross section of the said single yarn fiber. It is a cross-sectional schematic diagram which shows how to obtain | require the cross-sectional shape of another single yarn fiber, and the atypical degree of the cross section of the said single yarn fiber. 2 is a scanning electron micrograph showing a cross section of a single yarn fiber obtained in Example 1. FIG. 3 is a scanning electron micrograph showing a cross section of a single yarn fiber obtained in Comparative Example 3. FIG. It is the schematic of the measuring method of a yarn widening ratio.

The non-coating woven fabric for an airbag of the present invention includes a single yarn fiber having a substantially triangular cross section and an irregularity of 1.3 to 2.2, and has a cover factor (CF) of 2050 to 2600, with a difference of 20 kPa. It is characterized in that the air permeability under pressure is 0.25 L / cm ² / min or less.
The inventors of the present invention can fabricate airbag fabrics using a substantially triangular cross-section fiber having a specific atypical degree instead of the conventionally used round cross-section or atypical cross-section fibers, thereby achieving high density. The inventors have found that a woven fabric that can be woven, has a lower air permeability than a conventional non-coated fabric, and has a high sliding resistance value has been obtained, thereby completing the present invention. Hereinafter, the present invention will be described in detail.

The material of the fiber constituting the non-coated fabric for an airbag of the present invention is not particularly limited. For example, an aliphatic polyamide fiber such as nylon 66, nylon 6, nylon 46, nylon 12 or the like, an aroma such as aramid fiber. And polyester fibers such as group polyamide fiber, polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate. Also, wholly aromatic polyester fibers, ultra high molecular weight polyethylene fibers, polyparaphenylene benzobis oxazole fibers (PBO fibers), polyphenylene sulfide fibers, and polyether ketone fibers can be used. However, in consideration of economy, polyester fiber and polyamide fiber are preferable, and nylon 66 made of polyhexamethylene adipamide fiber is preferable from the viewpoint of durability against high temperature gas.

When using nylon 66 as a constituent fiber of the non-coating fabric for airbags, it is preferable to use nylon 66 having a relative viscosity of 3.2 or more due to sulfuric acid. If the relative viscosity is less than 3.2, the strength required for the airbag fabric may be insufficient. More preferably, it is 3.3 or more, More preferably, it is 3.4 or more. However, if the relative viscosity is too high, not only does the polymerization cost increase, but the spinning operability tends to deteriorate. Therefore, the relative viscosity is preferably 3.6 or less, more preferably 3.5 or less.

Fibers obtained from raw materials regenerated from plastic waste may be used for some or all of the fibers constituting the fabric. Moreover, the material which comprises a fiber may contain the various additive for improving the process passability in a manufacturing process. Examples of the additive include an antioxidant, a heat stabilizer, a smoothing agent, an antistatic agent, a thickener, and a flame retardant. Furthermore, the fibers constituting the airbag fabric may be original yarns or dyed after yarn production.

In the non-coated fabric for an airbag of the present invention, it is important to use a single yarn fiber having a substantially triangular cross section perpendicular to the fiber axis direction (hereinafter sometimes simply referred to as a substantially triangular cross section fiber).
By using fibers whose cross-sectional shape of the single yarn fibers is substantially triangular, weaving can be performed at high density on a loom, and a low-breathing fabric can be obtained. The present inventors consider the reason as follows. The fiber whose cross-sectional shape of the single yarn fiber is approximately triangular is the reason why when the external force is applied to the fiber, the single yarn fiber moves and is packed in a fine state to exhibit high density and low air permeability characteristics It is considered as one of
That is, the external force applied when wetting the weft with a scissors on a loom or constraining the weft with a warp, the single yarn fibers are closely packed as a result, compared to the fibers having a gap between the single yarn fibers, Even though the fineness is the same, the actual fiber diameter is small, so it is assumed that weaving can be performed at a higher density on the loom. In addition, the air permeability is lower than that of the conventional fabric because the fabric can be woven at a high density, the gap between the fibers during ventilation is reduced, and the single yarn fibers are closely packed by the pressure applied during ventilation. This is probably because the air permeability inside the fiber also decreases as a result of the decrease in the voids inside the fiber.

As described above, the reason for the movement of the single yarn fiber by the external force is that, when the shape appearing in the cross section perpendicular to the fiber axis direction of the single yarn fiber is a substantially triangular shape, the cross sectional shape is different from that of other polygonal fibers. The number of vertices is small, and there is little catching between single yarns.

The single yarn fiber used in the present invention has an irregularity of 1.3 or more and 2.2 or less. The degree of atypicality is used as an index of the atypical shape of the single yarn fiber cross section. Theoretically, the cross-sectional shape is preferably an equilateral triangle, but in the actual raw yarn, a phenomenon (die-swell phenomenon) that spreads when the molten resin is extruded from the nozzle occurs. The apex is rounded. For this reason, the most preferable variant in the present invention is centered around 1.6. The degree of profile is preferably 1.35 or more and 2.0 or less, more preferably 1.4 or more and 1.8 or less. If the degree of profile is too small, a gap is generated between the single yarn fibers, the air permeability of the fabric is lowered, and at the same time, the movement of the single yarn fibers may be suppressed. On the other hand, if the degree of atypicality is too large, the unevenness of the fiber surface becomes large, causing a catch between adjacent fibers, and the single yarn fiber may be difficult to move.
It should be noted that there is little change in the degree of irregularity before and after weaving, and usually the single yarn fiber after weaving has the same degree of irregularity as the single yarn fiber (original yarn) before weaving. Therefore, it is preferable that the degree of irregularity of the unwoven yarn taken out from the fabric is also in the above range. The atypical degree of the single yarn fiber cross section is determined by the method described in the examples.

As shown in FIG. 2, the single yarn fiber according to the present invention connects the apexes (a, b, c) of substantially triangles (outer periphery of the single yarn fiber cross section) 34 appearing in the cross section orthogonal to the fiber axis direction. It is preferable that the straight line is inside or on the outer periphery 34 of the cross section of the single yarn fiber. It is also preferable that the triangle 33 connecting the vertices a, b, and c of the substantially triangle 34 with a straight line is inside the outer periphery 34 of the single yarn fiber cross section. This relationship is the intersection 22 of the perpendicular bisector 21 of line segments ab, bc, and ca connecting the vertices a, b, and c of the outer periphery 34 of the single yarn fiber cross section and the outer periphery 34 of the single yarn fiber cross section. Is synonymous with being located outside the triangle 33. As the single yarn fiber according to the present invention, an ideal one in which the shape appearing in the cross section orthogonal to the fiber axis direction is an equilateral triangle is ideal. In this case, the triangle 33 coincides with the outer periphery 34 of the single yarn fiber cross section.

On the other hand, for example, as in the fiber shown in FIG. 3, the shape 34 ′ that appears in the cross section orthogonal to the fiber axis direction and the apex (a ′, b ′, c ′) connecting straight lines (eg, a′b ′) and / or shape (triangle 33 ′) are not in the above-described relationship, ie, the triangle 33 ′ is not within the outer circumference 34 ′ of the fiber cross section (substantially This means that the cross-sectional shape of the single yarn fiber is close to the Y shape), and the amount of voids between the single yarn fibers increases, so that not only the air permeability is increased, but also inside the fiber (multifilament) The single yarn fibers tend to be difficult to move.

In order to obtain a single yarn fiber that can easily move in the multifilament by an external force, it is preferable to lower the entanglement degree of the fiber. The number of entanglements in the raw yarn production stage is preferably 5 / m or more and 30 / m or less for high-density weaving. The entanglement degree of the yarn at the stage of weaving from the woven fabric is preferably 20 pieces / m or less, more preferably 15 pieces / m or less, and even more preferably 8 pieces / m or less in terms of the average value of warp and weft. There is no particular lower limit, and the degree of entanglement may be 0 / m. If the entanglement degree is within the above range, the movement of the single yarn fiber is hardly inhibited, and a non-coated fabric for an air bag having a high density and a low air permeability can be obtained. In addition, the entanglement degree in the raw yarn stage is more preferably 8 pieces / m or more, and further preferably 10 pieces / m or more. The upper limit of the entanglement degree is more preferably 28 pieces / m or less, and further preferably 25 pieces / m or less.

The ease of movement of the single yarn fibers constituting the fibers can also be grasped from the widening rate of the yarn (fiber) taken out by unweaving the non-coating fabric for airbag. Therefore, in the present invention, the yarn widening ratio is moved so that the single yarn fibers are closely packed in the fiber by an external force such as tension, and the single yarn fibers are displaced at the interface with the adjacent single yarn fibers. Thus, it is used as an index indicating a state of moving in a direction orthogonal to the fiber axis. A large value of the widening ratio means that the single yarn fiber is easy to move due to the influence of external force.

It is preferable that the fiber widening rate of the fiber taken out by weaving the non-coated fabric for airbag is 2.4 or more and 3.5 or less. When the yarn widening ratio is less than 2.4, the single yarn fiber is difficult to move, and when an external force is applied to the fiber, the single yarn fiber is difficult to densely fill, making it difficult to weave more densely. Tend to be. Accordingly, the yarn widening ratio is more preferably 2.5 or more, and even more preferably 2.6 or more. If the yarn widening ratio is higher than 3.5, the single yarn fibers are likely to move too much, and the gap between the single yarn fibers cannot be maintained tightly and the air permeability may be increased. More preferably, it is 3.4 or less. The yarn widening ratio is obtained by a measuring method described later.

From the viewpoint of satisfying the mechanical properties required for the airbag, the mechanical properties of the fibers constituting the non-coated fabric for the airbag are preferably such that the cutting strength is 7.0 cN / dtex or more, more preferably It is 7.5 cN / dtex or more. The cutting strength is preferably higher, but considering the yield during production, etc., it is preferably 9.5 cN / dtex or less, more preferably 9.0 cN / dtex or less.

It is preferable that the single yarn fineness of the filament constituting the fiber is 1 dtex or more and 8 dtex or less. If the single yarn fineness is too large, the number of single yarn fibers per the same fineness will decrease, and the air permeability inside the fibers will increase, and it may be difficult to obtain a low-breathing airbag. On the other hand, if the single yarn fineness is too small, the productivity of the fiber may be lowered. More preferably, it is 2 dtex or more and 7.5 dtex or less, More preferably, it is 2.5 dtex or more and 6.5 dtex or less.

The number of filaments constituting the fiber is preferably 40 or more and 200 or less. When the number of filaments is less than 40, the air permeability inside the fiber is high, and it is difficult to obtain a low-breathing airbag. On the other hand, when the number of filaments exceeds 200, the productivity of fibers tends to decrease. The number of filaments is more preferably 50 or more, further preferably 60 or more, more preferably 180 or less, and still more preferably 160 or less.

The total fineness of the fiber is not particularly limited, but is preferably 100 dtex or more and 600 dtex or less, more preferably 150 dtex or more and 500 dtex or less, further preferably 200 dtex or more and 500 dtex or less, and 235 dtex or more and 470 dtex or less. Is particularly preferred. If the total fineness is less than 100 dtex, the tensile strength and tear strength may be insufficient when the fabric is used for an airbag. On the other hand, if it exceeds 600 dtex, strength problems are unlikely to occur, but the flexibility required for the airbag is impaired, and the fabric surface becomes hard, which may damage the human skin at the time of collision. .

The structure of the non-coated fabric for the airbag is not particularly limited, but a plain weave is preferable considering the uniformity of the fabric properties. The warp yarns and weft yarns do not have to be the same, and the thickness, the number of yarns, the type of fiber, and the like may be different as long as strength, air permeability, etc. satisfying the performance as an airbag are obtained. From the viewpoint of making the fabric low in air permeability, the cross-sectional shape described above is substantially triangular in 100% of the fibers constituting the non-coating fabric for airbags (the total of warp and weft), and has a specific degree of irregularity. It is preferable to use 25% or more of fibers (multifilament) including single yarn fibers. More preferably, it is 50% or more, and most preferably 100%.

The non-coating fabric for an airbag has a cover factor (CF) calculated by the following formula 1 of 2050 or more and 2600 or less. If the cover factor exceeds 2600, the warp is damaged by the tension applied to the warp during weaving, and it may become difficult to weave at high density. Moreover, if it is less than 2050, there exists a possibility that it may become difficult to obtain the low air permeability required as an airbag. The cover factor is more preferably 2200 or more and 2500 or less.
CF = (warp density [w / 2.54 cm]) × √ (warp fineness [dtex] × 0.9) + (weft density [w / 2.54 cm] × √ (weft fineness [dtex] × 0.9) (Formula 1)

The non-coating fabric for an airbag has an air permeability (high-pressure air permeability) under a differential pressure of 20 kPa of 0.25 L / cm ² / min or less. When the high-pressure air permeability exceeds 0.25 L / cm ² / min, the low air permeability necessary for an airbag cannot be ensured. High air permeability is more preferably less 0.20L ^/ cm 2 ^/ min, more preferably not more than 0.15L ^/ cm 2 ^/ min.

Moreover, it is preferable that the non-coating fabric for airbags has a high-pressure air permeability (air permeability under a differential pressure of 20 kPa) after being folded by a predetermined method of 0.30 L / cm ² / min or less. The airbag fabric is folded or stored in a predetermined position in the vehicle in a compressed state, so if the air permeability after folding is high, it is difficult to secure the internal pressure necessary to restrain the passenger when the airbag is deployed. Tend to be. High pressure air permeability after folding, more preferably not more than 0.25L ^/ cm 2 ^/ min, more preferably not more than 0.20L ^/ cm 2 ^/ min. The high-pressure air permeability after folding the airbag fabric is determined by the method described in the examples.

Furthermore, it is preferable that the non-coating woven fabric for an airbag has an air permeability change rate (the following formula 2) represented by a ratio of the high-pressure air permeability before and after folding to 150% or less. If the rate of change in air permeability exceeds 150%, it may be difficult to secure the internal pressure necessary for restraining the occupant when the airbag is deployed. More preferably, it is 130% or less, More preferably, it is 120% or less.
Air permeability change rate (%) = (high pressure air permeability after folding) / (high pressure air permeability before folding) × 100 (Formula 2)

It is preferable that the non-coating fabric for airbags has a sliding resistance defined by ASTM D6479 and an average value in the vertical direction and the horizontal direction is 700N or more and 1200N or less. When the sliding resistance is less than 700 N, the sewing part opens when the airbag is deployed, and air permeability as an airbag is deteriorated, which is not preferable. On the other hand, if the slip resistance exceeds 1200 N, the fabric becomes stiff, so the flexibility required for the airbag is impaired, and the fabric surface becomes hard, which may damage the human skin at the time of collision. is there. More preferably, they are 750N or more and 1100N or less, More preferably, they are 800N or more and 1050N or less.

Next, the fiber used for the non-coating fabric for airbags of the present invention and the method for producing the non-coating fabric for airbags using the same will be described.
What is necessary is just to manufacture the fiber which comprises the non-coating fabric for airbags in accordance with a conventional method. For example, raw resin is melt-extruded using a single-screw or twin-screw extruder, weighed using a gear pump, extruded into a nozzle through an appropriate metal nonwoven fabric filter, and then melted into a fiber. The product is passed through a heating cylinder directly under the nozzle as it is, cooled with cooling air, applied with a spinning oil agent, wound around a take-up roller, stretched as it is, and then subjected to an entanglement treatment to obtain a filament.

As described above, the fibers constituting the non-coated fabric for an airbag of the present invention have a substantially triangular cross section and have a specific degree of atypical shape. In order to obtain such a fiber, it is preferable to perform spinning using a nozzle having an appropriate shape. For example, using a nozzle in which three discharge holes are arranged so that the outer edge surrounding the hole is substantially triangular, the resin discharged by the die-swell phenomenon in which the molten resin spreads immediately after being discharged from the nozzle is joined A method of forming a thread shape; a method of discharging molten resin from three linear slits using a nozzle having a Y-shaped discharge hole; or three substantially isosceles triangles as shown in FIG. And a method of discharging molten resin from a nozzle having a discharge hole shape in which adjacent isosceles triangles are arranged so as to share the end of the base.

Since the degree of irregularity of the fiber cross section largely depends on the degree of irregularity of the nozzle, in order to obtain a fiber having a substantially triangular sectional shape having a specific degree of irregularity, a nozzle having a discharge hole shape as shown in FIG. 1 is used. It is preferable. By using the nozzle of this shape, it becomes easy to adjust the profile of the fiber cross section.
The atypical degree of the nozzle is preferably 2 or more and 10 or less, and more preferably 3 or more and 8 or less. If the nozzle profile is too small, the fiber cross-section after yarn forming tends to be a shape close to a round cross-section. On the other hand, if the degree of atypical shape of the nozzle is too large, the cross section of the fiber after yarn forming tends to be flat or a shape close to the Y shape.

The degree of irregularity of the nozzle can be expressed by the ratio of the radius between the circumscribed circle and the inscribed circle of the nozzle hole (radius of the circumscribed circle / radius of the inscribed circle). Specifically, the circumscribed circle 11 is a circle represented by a broken line in FIG. 1 and passing through the vertices A, B, and C of the nozzle discharge hole outer edge 13. On the other hand, the inscribed circle 12 is represented by an alternate long and short dash line in FIG. 1, and the adjacent isosceles triangles when the discharge hole is regarded as a shape composed of three approximately isosceles triangles having the vertices A, B and C as vertices. Are circles that pass through intersections D, E, and F of equal sides.

The nozzle temperature may be appropriately determined according to the resin to be used. For example, when using a polyamide fiber such as nylon 66, the nozzle temperature is preferably 280 ° C. or higher and 320 ° C. or lower. If the nozzle temperature is too low, pressure loss when passing through the nozzle increases, and spinning may be difficult. On the other hand, if the nozzle temperature is too high, polymer degradation and gelation are likely to occur, which causes clogging of the filter and breakage of the filter, which not only decreases productivity but also decreases fiber strength. There is a fear.

In order to make the temperature of the nozzle surface uniform, an apparatus such as a heat insulating cylinder or a heating cylinder may be installed between the nozzle and the take-up roll for winding the fiber. The length of the heat insulating cylinder or the heating cylinder is preferably in the range of 2 cm to 50 cm from the nozzle, for example. When the length of the heating cylinder is shorter than 2 cm, the cooling air in the subsequent cooling process enters, and the temperature of the nozzle surface becomes non-uniform, and fineness spots may easily occur between the fibers. On the other hand, when the heat insulating cylinder or the heating cylinder is longer than 50 cm, periodic longitudinal unevenness called so-called resonance tends to occur.

The temperature of the cooling air used for cooling the melted yarn is preferably in the range of 15 ° C to 30 ° C. If the temperature of the cooling air is lower than 15 ° C., there may be a large difference in physical properties such as the degree of atypicality and strength between the fibers. There is. More preferably, it is 18 degreeC or more and 28 degrees C or less, More preferably, it is 20 degreeC or more and 25 degrees C or less.

The wind speed of the cooling air is preferably in the range of 0.1 m / sec to 1 m / sec. If it is less than 0.1 m / sec, it may be difficult to sufficiently cool the thread shape, and fineness spots may easily occur between the fibers. On the other hand, if the wind speed exceeds 1 m / sec, the cooling speed is likely to be different between the upstream side and the downstream side of the cooling air, and fineness unevenness may occur between the fibers.

Moreover, when winding the cooled yarn, it is preferable that the draft ratio calculated by the following formula 3 is 100 or more and 150 or less.
Draft ratio = take-up roller speed [m / min] / (single hole volume discharge [m ³ / min] / nozzle hole cross-sectional area [m ² ]) (Formula 3)
When the draft ratio is less than 100, the yarn swaying is increased, and there is a tendency that fusion between fibers and yarn breakage are easily caused. On the other hand, when the draft ratio is larger than 150, the molecular chain orientation unevenness in the cross section of the single yarn fiber, particularly the molecular chain orientation difference between the central portion of the cross section and the apex of the substantially triangle increases, resulting in problems such as strength reduction. Tends to occur.

The draw ratio is preferably 4.5 times or more and 4.9 times or less. If the draw ratio is less than 4.5 times, the strength of the fiber may decrease. On the other hand, if the draw ratio is higher than 4.9 times, molecular chain alignment spots are generated in the filament cross section, cracks are likely to occur in the filament, and fiber strength is reduced, and yarn breakage is likely to occur during fiber production. There is a fear.

Although the temperature during stretching depends on the subsequent weaving method, it is preferably in the range of 20 ° C. or higher and 240 ° C. or lower. If the drawing temperature is lower than 20 ° C., thread breakage may occur before the necessary draw ratio is reached. On the other hand, when the stretching temperature exceeds 240 ° C., the yarn is melted and the stretching tends to be difficult.

In the fibers used in the non-coating fabric for an air bag of the present invention, it is preferable that the entanglement by the fluid treatment such as air pressure, that is, the so-called interlace treatment is kept to a minimum. Specifically, the entanglement degree of the fiber at the raw yarn stage is preferably 5 / m or more and 30 / m or less. In order to make the degree of entanglement within the above-mentioned range, it is preferable to adjust the degree of fiber entanglement by performing an interlace treatment after the drawing process and before winding.

If the degree of entanglement is too small, fluff is likely to occur in the next process, that is, the weaving process, and the fabric may be deteriorated in quality. On the other hand, if the degree of entanglement is too large, a large number of entanglements remain even in the state of the woven fabric after weaving, which may impede the movement of the single yarn fibers. Therefore, the degree of entanglement at the raw yarn stage is preferably within the above range.

In the fiber used for the non-coating fabric for airbags of the present invention, the boiling water shrinkage rate is not particularly limited, but the boiling water shrinkage rate is 7% or more and 12% or less in order to increase the slip resistance of the airbag fabric. It is preferable to do. If the boiling water shrinkage rate is too small, there is a risk that the slip-off resistance will be small because the tightness between the fibers is small when processing is performed in the manufacturing process of the airbag fabric. On the other hand, if the boiling water shrinkage is too large, the stability of the fibers over time is poor, and this is not preferable because it causes a large variation in fabric properties depending on the storage period. More preferably, they are 8% or more and 11% or less, More preferably, they are 8.5% or more and 10% or less.

The method for weaving the non-coated fabric for airbag is not particularly limited, and a conventionally known method may be used. For example, the warp tension during weaving is preferably 0.1 cN / dtex or more and 0.5 cN / dtex or less. More preferably, it is 0.15 cN / dtex or more and 0.4 cN / dtex or less, More preferably, it is 0.18 cN / dtex or more and 0.35 cN / dtex or less. When the warp tension is lower than 0.1 cN / dtex, it is difficult to weave the fabric at a high density, and the entanglement degree of the warp is easily maintained, and the low ventilation required for the airbag when the fabric is used. It may be difficult to obtain sex. If it is higher than 0.5 cN / dtex, the force applied to the warp is too great and fluff may occur.

The loom used for weaving is not particularly limited, and a water jet loom, an air jet loom, a rapier room, or a multiphase loom is preferably used. The water jet loom is preferable from the viewpoint of speeding up, widening, and machine price.

The operation method of the loom used for weaving is not particularly limited, and may be, for example, a crank-type opening loom or a cam-type opening loom. However, from the viewpoint of increasing the density of the woven fabric, as is well known, it is preferable to use a cam-type opening loom with a long wrinkle opening time because the weft flying is stable and weaving can be performed at a higher density on the machine. .

When weaving a non-coated fabric for an airbag, the loom rotation speed is preferably 400 rpm or more and 1000 rpm or less. If the loom rotational speed is too slow, productivity is impaired, which is not preferable. On the other hand, if the loom rotational speed is too fast, it is difficult to stably weave at a high density. More preferably, it is 500 rpm or more and 900 rpm or less, More preferably, it is 550 rpm or more and 800 rpm or less.

When weaving a non-coated fabric for an airbag, it is very important to improve the weaving efficiency to make the wefts fly stably. In order to achieve stable weft flying, one condition is that a sufficient opening area is created by wefting up and down when wefts are inserted, but weaving the fabric at a higher density. In this case, weaving becomes difficult because the pre-weaving from the temple holding the woven fabric protrudes and the opening area is not sufficiently secured.

The non-coating woven fabric for airbags according to the present invention containing substantially triangular cross-section fibers can be woven while suppressing the protrusion before weaving. Therefore, the weaving efficiency of the conventional woven fabric is improved even when weaving under higher density conditions. The inventors have found that it can be maintained at the same time. That is, the substantially triangular cross-section fibers of the present invention are densely packed between single yarn fibers by external force applied when wefts are hammered on a loom or when wefts are constrained with warps. Compared to fibers with gaps, the actual fiber diameter is small even if the fineness is the same, so it is presumed that weaving can be performed at a higher density on the loom.

In order to suppress the amount of protrusion even when weaving at a higher density than before, it is necessary to take a form in which the fibers are closely packed without gaps between the single yarn fibers when subjected to external force. Therefore, the amount of protrusion is not limited to a substantially triangular cross-section fiber, and other shapes such as a polygonal shape such as a regular hexagonal shape and a regular square shape, and a rhombus shape are also conceivable. However, the substantially triangular cross-sectional fiber shape of the present invention is preferable from the viewpoint of easy movement of fibers constituting the fabric, low air permeability of the fabric, and low air permeability even after folding.

In particular, during weaving, when performing high density weaving in which the cover factor (cf) of the weft obtained by the following formula 4 is 1040 or more, it is preferable to use an atypical fiber typified by a substantially triangular cross-section fiber. In the case of developing a high density and low air permeability property, it is preferable that the gap between the fibers has a linear shape, and therefore a polygonal shape is preferable. A shape in which two or more triangular cross-sectional shapes and other polygonal shapes are connected is also preferable. Therefore, there is no problem even in the shape of a rhombus with a bias applied to a quadrangle. However, as the number of vertices of the polygon increases, the closer to the round cross section, and the more complex the shape, the easier it is to create a gap between single yarn fibers when receiving external force, so the number of vertices is 3 or more and 6 or less. It is preferable. More preferably, they are 3 or more and 4 or less, More preferably, they are three substantially triangular cross-section fibers.
Ft of weft during weaving = (weft driving setting [mains / 2.54 cm]) × √ (weft fineness [dtex] × 0.9) (Formula 4)

As one index for examining whether the opening area is sufficiently secured, there is a method for examining the protruding amount of the ear. The protruding amount of the ear portion tends to increase as compared with the central portion of the fabric, and is also a factor that hinders stable flying of the weft.
The reason for the difference in the amount of protrusion between the ear part and the center part of the fabric is that the warp crimp is strongly formed in the center part of the fabric due to the tension along the fiber axis against the weft by the adjacent warp. Then, since there is no warp on one side, the wefts are loosened and the warp crimps are weakly formed, so it is assumed that this results in a difference in warp length between the central part of the fabric and the ear part.

It is preferable that the amount of protrusion measured by the predetermined method set forth in the examples is 320 ° to 350 °. In this measurement, which uses a strobe, the position where the wrinkle is completely driven is set to 0 ° = 360 °, and the time point at which the wrinkle hits the weave on the nozzle side after the weft has been driven is recorded. The smaller the amount, the higher the amount of protrusion. If the protruding amount is less than 320 °, the opening area is not sufficiently secured, so that weft flight is not stable and weaving efficiency is not increased, which is not preferable. When the protruding amount is larger than 350 °, it is an area in which weaving as a high-density fabric is practically impossible. More preferably, they are 325 degrees or more and 340 degrees or less, More preferably, they are 327 degrees or more and 335 degrees or less.

An index indicating weaving efficiency is the number of stops of weft driving. As mentioned above, if weft jumping is impossible due to excessive densification, or if weaving conditions such as warp tension and weaving machine timing are not set properly, weaving cannot be performed and It will stop. It is preferable that the number of stops of weft driving when weaving the airbag fabric is 4 times / 100 m or less. If it stops more than this, production efficiency falls and it is not preferable. More preferably 3 times / 100 m or less, and still more preferably 2 times / 100 m or less.

The processing method after weaving the non-coated fabric for an airbag is not particularly limited. Therefore, any processing may be applied as long as the above-described characteristics of the present invention, that is, the characteristics that the single yarn fiber moves in the woven fabric due to the influence of external force can be maintained. Examples of the processing method of the non-coating fabric for airbag after weaving include heat treatment such as scouring, drying, and heat setting. These may be carried out alone or in combination of two or more.
Specifically, as a mode of combination of processing methods of fabric after weaving, a mode in which a green machine woven in a water jet loom is naturally dried or subjected to a heat treatment process for drying; a green machine woven in various looms is used in a scouring process. Examples include an embodiment in which the raw material woven by various looms is subjected to a scouring step and then subjected to a heat treatment step for heat setting. Of course, the fabric (raw machine) that has been woven on the loom may be cut and sewed as it is without being subjected to the processing steps as described above to form an airbag.

First, a mode in which a green machine woven in a water jet loom is naturally dried or subjected to a heat treatment step for drying will be described (hereinafter sometimes referred to as a first mode). When the heat treatment step at a specific temperature is performed, the heat treatment temperature (drying temperature) of the living machine is set to 20 ° C. or more and 190 ° C. or less. Preferably they are 40 degreeC or more and 160 degrees C or less, More preferably, they are 60 degreeC or more and 140 degrees C or less. The heat treatment time (drying time) is preferably 10 seconds to 5 minutes. More preferably, it is 20 seconds or more and 3 minutes or less, More preferably, it is 30 seconds or more and 2 minutes or less. In the heat treatment process, it is sufficient that the living machine can be heat treated at the above temperature, and the method is not particularly limited. Therefore, the apparatus for performing the heat treatment step is not particularly limited. For example, a dryer (dryer type heating furnace) using hot air as a heating medium, a cylinder dryer using hot air or steam as a heating medium, etc. Any of them can be used. In the first embodiment, instead of the heat treatment step, the weaving machine after weaving may be naturally dried to complete the airbag fabric.

In an embodiment in which a raw machine woven by various looms is subjected to a scouring process and then subjected to a heat treatment process for drying (hereinafter sometimes referred to as a second aspect), after weaving, the raw machine is 50 ° C. or higher and 100 ° C. or lower. A hot water treatment to pass through the water tank is performed (scouring process). In the hot water treatment, the fabric is contracted while removing the oil agent, the sizing agent, and the like applied in the spinning process and the weaving process from the fabric. When the temperature of water is less than 50 ° C., it may be difficult to sufficiently shrink the fabric. The temperature of water is more preferably 60 ° C. or higher and 98 ° C. or lower, and further preferably 70 ° C. or higher and 95 ° C. or lower. The hot water treatment is preferably performed for 10 seconds or more and 3 minutes or less. More preferably, it is 20 seconds or more and 2 minutes or less, More preferably, it is 30 seconds or more and 1 minute or less. The water used in the hot water treatment includes tap water, pure water, surfactants such as sodium alkylbenzene sulfonate, alkaline scouring agents such as soda ash, enzymes, or an aqueous solution in which one or more organic solvents are dissolved. May be used.

Also, the hot water treatment is preferably performed while applying a tension of 0.040 cN / dtex or less in the warp direction of the raw machine. By performing the hot water treatment under a predetermined tension, the yarns in the raw machine can be rearranged by sufficiently shrinking the fabric. Further, when polyamide fibers such as nylon 66 are used, hydrogen bonds in the fibers are more likely to be broken due to the presence of water, which makes it easier to obtain a more flexible base fabric. When the tension in the warp direction exceeds 0.040 cN / dtex, the fabric is difficult to freely shrink during the hot water treatment, and the property that the fabric itself is close to the state of being heat-set in a tension state is easy to move. There is a risk of being easily damaged.

Next, the fabric subjected to the scouring process (warm water treatment) is subjected to a heat treatment process. In the heat treatment step according to the second aspect, it is preferable to dry the woven fabric without performing heat setting. For the same reason as the hot water treatment, the tension in the warp direction in the heat treatment (drying) step is also preferably 0.040 cN / dtex or less.
The heat treatment temperature (drying temperature) is preferably 150 ° C. or less from the viewpoint of ensuring low air permeability of the airbag fabric. More preferably, it is 140 degrees C or less. The drying temperature is preferably low, but if it is too low, the drying time becomes long, which is not industrially preferable. Preferably it is 100 degreeC or more, More preferably, it is 110 degreeC or more. The heat treatment time is preferably 10 seconds to 5 minutes. More preferably, it is 20 seconds or more and 3 minutes or less, More preferably, it is 30 seconds or more and 2 minutes or less.

In an embodiment in which a raw machine woven by various looms is subjected to a scouring process and then subjected to a heat treatment process for heat setting (hereinafter sometimes referred to as a third aspect), in the scouring process, relatively low temperature water, Specifically, water at 30 ° C. or higher and 90 ° C. or lower is used. The temperature of water is preferably 40 ° C. or higher and 80 ° C. or lower, and more preferably 50 ° C. or higher and 70 ° C. or lower. If it is in the said temperature range, the oil agent, sizing agent, etc. which are provided by a spinning process or a weaving process can be efficiently removed from a textile fabric.

As long as water at a specific temperature is used, the scouring process is not limited, and a conventionally known scouring method can be employed. As water used in the scouring process, in addition to tap water and pure water, surfactants such as sodium alkylbenzene sulfonate, alkaline scouring agents such as soda ash, enzymes, and an aqueous solution in which one or more organic solvents are dissolved. May be used.

Further, the scouring process may be performed while applying tension in the running direction of the raw machine and the direction (width direction) perpendicular to the running direction. For example, the overfeed rate in the running direction of the living machine is preferably 0% or more and 5% or less, more preferably 1% or more and 4% or less, and further preferably 2% or more and 3% or less. On the other hand, the overfeed rate in the width direction of the production machine is preferably 0% or more and 3% or less, more preferably 0.5% or more and 2.5% or less, and further preferably 1% or more and 2% or less. is there.

The scouring treatment is preferably performed for 10 seconds to 5 minutes. More preferably, it is 20 seconds or more and 3 minutes or less, More preferably, it is 30 seconds or more and 2 minutes or less. The scoured woven fabric (growth machine) may be subjected to a dehydration or drying treatment and then subjected to a heat treatment step. In the heat treatment step, the woven fabric is heated to 110 ° C. or higher, so that the drying treatment or the like is not performed. The scoured fabric may be directly subjected to a heat treatment step.

Next, the scoured fabric is heat treated at 110 ° C. or higher and 190 ° C. or lower (heat treatment step). The heat treatment temperature is preferably 120 ° C. or higher, more preferably 130 ° C. or higher, preferably 185 ° C. or lower, more preferably 180 ° C. or lower, and further preferably 175 ° C. or lower. If the heat treatment temperature is too low, it tends to be necessary for a long time to dry the woven fabric wetted by the scouring treatment. There is a possibility that the mesh becomes large and the air permeability becomes high. On the other hand, if the heat treatment temperature is too high, not only the fibers constituting the fabric may be thermally deteriorated and the mechanical strength may be lowered, but also the fabric is hardened by heat shrinkage and the fabric is cured. There is a possibility that the property that the single yarn fiber is easy to move is likely to be impaired.

In the third aspect, heat treatment is performed while applying tension to the fabric (heat setting). From the viewpoint of obtaining a woven fabric having a lower air permeability, it is preferable to supply the woven fabric to the heat treatment step so as to overfeed. The overfeed rate in the running direction of the fabric is 1.5% or more and 6.0% or less, preferably 2.0% or more and 5.0% or less, more preferably 2.5% or more and 4.5% or less. It is. On the other hand, the overfeed rate (width filling rate) in the direction (width direction) orthogonal to the running direction of the fabric is 1.0% to 4.0%, preferably 1.5% to 3.5%. More preferably, it is 2.0% or more and 3.0% or less.
In addition, when supplying the raw machine in an overfeed state in both the scouring step and the heat treatment (heat setting) step, the overfeed rate in the running direction of the fabric should be 0% or more and 5.0% or less in the heat setting step. Is more preferably 1.0% or more and 4.0% or less, and further preferably 1.5% or more and 3.0% or less. On the other hand, the overfeed rate (width filling rate) in the direction orthogonal to the running direction of the fabric (width direction) is preferably 0% or more and 3.0% or less, more preferably 0.5% or more and 2.5%. % Or less, more preferably 1.0% or more and 2.0% or less.

Here, the overfeed rate in the running direction of the fabric is a value represented by the following formula 5. The speed of the feed roller (V ₁ ) that is upstream of the heat treatment process and supplies the fabric to the heat treatment process is made higher than the speed of the take-up roller (V ₂ ) that is downstream of the heat treatment process. State.
Overfeed rate in travel direction (%) = (V ₁ / V ₂ ) × 100 (Formula 5)
[V ₁ : Feed roller speed, V ₂ : Winding roller speed]

On the other hand, the overfeed rate in the direction (width) orthogonal to the running direction of the fabric is a value represented by the following formula 6. Usually, the heat treatment process is performed in a state where both ends in the width direction of the fabric are fixed, but the distance from one fixed end to the other end is made narrower than the width of the fabric before supplying the heat treatment process. It can be in an overfeed state.
Overfeed rate (%) in the direction perpendicular to the running direction of the fabric = (1−L ₀ / L ₁ ) × 100 (Formula 6)
[L ₀ : width (m) of the previous woven fabric supplied to the heat treatment step, L ₁ : width (m) of the woven fabric supplied to the heat treatment step]

If the overfeed rate in the running direction and the width direction of the woven fabric is within the above-mentioned range, the movement of the single yarn fiber when the woven fabric receives an external force and the spreading of the woven yarn in the direction perpendicular to the fiber axis suitably occur. Therefore, it is preferable. If the overfeed rate is too small, the yarn shrinks during heat treatment, and the single yarn fiber itself is excessively tensioned. Therefore, the single yarn fiber is difficult to move even when external force is applied, or the yarn is woven in the direction perpendicular to the fiber axis. There is a risk that the yarn will not easily spread and the air permeability will increase. On the other hand, if the overfeed rate is too large, the crimp becomes large due to the contraction force of the fibers, which may cause gaps between the fibers and deteriorate the air permeability.

What is necessary is just to implement a heat setting using a well-known apparatus and a heating means together. As such an apparatus, for example, an apparatus for holding a fabric called a pin tenter or a clip tenter can be cited. As the heating means, for example, a dryer type heating furnace can be used.
An airbag can be obtained by cutting, sewing or welding the above-described non-coated fabric for an airbag so as to have a desired shape.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited by the following examples, but may be appropriately modified within a range that can meet the purpose described above and below. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.

(1) Total fineness It measured based on JIS L1095 9.4.1.

(2) Filament number It calculated based on 8.4 of JIS L1013 (1999).

(3) Strength and elongation JIS L1017 8.5 a) According to the standard test definition, after leaving for 24 hours in a room where temperature and humidity are controlled at 20 ° C. and 65% RH, a tensile tester (made by Orientec Co., Ltd.) Strength and elongation were obtained by “Tensilon Universal Material Testing Machine”).

(4) Boiling water shrinkage rate Measured by (a) skein shrinkage rate (Method A) described in 8.18.1 of JIS L1013 (1999).

(5) Weaving density (number of driven)
It measured based on 8.6 of JIS L1096 (1999).

(6) Sectional shape and degree of profile Using a scanning electron microscope, a section of five arbitrarily selected fibers is photographed (magnification 1000 to 2000). Using commercially available software (for example, NIS-Elements Documentation), in the obtained cross-sectional photograph of the fiber, three substantially vertexes (referred to as “a”, “b”, and “c”) of the triangular shape appearing on the cross section of the fiber are selected. A circle that passes through points a, b, and c and circumscribes the fiber cross section is drawn (circumscribed circle 31). Next, a perpendicular bisector 21 of line segments ab, bc, and ac connecting the vertices is drawn, and passes through three intersections 22 of the fiber cross section intersecting with the vertical bisector 21 and inscribed in the fiber cross section. Describe a circle (inscribed circle 32). A value obtained by dividing the radius of the circumscribed circle 31 by the radius of the inscribed circle 32 was defined as the degree of irregularity (see FIGS. 2 to 5). The average degree of the five filaments was used as the degree of profile. The atypical degree of the nozzle hole was calculated in the same manner.
In addition, when the fiber cross-sectional shape is a shape other than a substantially triangular shape, a circumscribed circle and an inscribed circle that are in contact with the outer edge of the fiber cross section are set, and the degree of irregularity is obtained from the ratio of these radii. When a plurality of inscribed circles could be drawn in the fiber cross section, the atypical degree was obtained using the radius of the smallest inscribed circle.

(7) Yarn Widening Ratio As shown in FIG. 6, fibers (multifilament) 61 are bundled so as to have a circumference of 20 cm to form a single ring. The fiber 61 is suspended through a Teflon (registered trademark) rod 62 having a diameter of 1 cm, in which the ring portion is horizontally installed. At this time, the position of the binding point 64 is adjusted so that the binding point 64 does not come on the Teflon (registered trademark) rod 62 and the lowest point. A load 63 that is 1.52 times the total fineness (dtex) of the fiber is suspended from the lowest point of the annular fiber 61. The load 63 is hung on the fiber 61 via a bonding thread 67 using the fiber used for the measurement. In this state, the fiber width (a) of the multifilament located at the top of the Teflon rod 62 and the fiber located 5 cm above the load point on the side without the binding point 64 (the bottom point of the fiber 61). The thickest fiber width (b) is measured, and the ratio (a / b) between them is calculated. The above measurement was repeated 10 times while changing the fiber, and the average value was defined as the yarn widening ratio. The yarn widening ratio of the unwoven yarn from the woven fabric was also measured by the same method.

(8) High pressure air permeability (air permeability under differential pressure of 20 kPa)
Using five high-pressure air permeability measuring machines (manufactured by OEM System Co., Ltd.) at five measurement sites randomly selected from the portion excluding the range of 30 cm from both ends in the width direction of the fabrics obtained in Examples and Comparative Examples. Then, the air permeability under a differential pressure of 20 kPa was measured, and the average value was taken as the high pressure air permeability.

(9) High pressure air permeability after folding (air permeability under differential pressure of 20 kPa)
Five test pieces of 20 cm square are cut out from any part excluding the range of 30 cm from both ends in the width direction of the woven fabric, the test pieces are folded in half along the fiber axis direction (a), and the fiber axis direction (a ) Along the fiber axis direction (b) perpendicular to the fiber axis direction (a), and again along the fiber axis direction (b) perpendicular to the fiber axis direction (a). Folded in half and folded in 5cm square. A load of 50 N was applied to the entire surface of the folded test piece for 1 minute, and then the test piece was left for 1 minute in a state of being expanded to 20 cm square. A circular portion having a diameter of 10 cm centering on the intersection of the first fold and the second fold is used as a measurement site, and the air permeability under a pressure difference of 20 kPa is measured using a high pressure air permeability measuring machine (manufactured by OEM System Co., Ltd.). Measured. The average value of the five test pieces was taken as the high-pressure air permeability after folding.

(10) Air permeability change rate The air permeability change rate before and after folding was determined by the following equation 2.
Permeability change rate (%) = (High-pressure air permeability after folding) / (High-pressure air permeability before folding) x 100 (Formula 2)

(11) Entanglement degree The entanglement degree of the raw yarn and the unwoven yarn was calculated based on JIS L1013 8.15.

(12) Sliding resistance force Measured according to ASTM D 6479.

(13) Projection amount before weaving Using a commercially available stroboscope, the timing when the heel was completely driven was set to 0 ° = 360 °, and the stroboscope was placed on the dial scale mounted on the water jet loom. The scale was set to zero. After the weft was inserted, the timing at which the heels contacted the protrusion before weaving on the nozzle side was read. Three measurements were taken every hour, and the average value for the three was recorded.

(14) Number of stops The number of stops of weft driving was measured according to the following formula 7.
Number of stops of weft driving (times / 100 m) = {(s ₀ −s ₁ ) / f ₁ × 100
(Formula 7)
[S ₀ : Total number of stops of weft driving when weaving a certain brand (times), s ₁ : Number of times weft yarn cheese is switched (times), f ₁ : Weaving total length (m) of a brand

<Example 1>
Polyamide 66 resin was melt-extruded using a single-screw extruder, weighed using a gear pump, and the hole shape was processed into the shape shown in FIG. 1 through a metal nonwoven fabric filter (NF-07 manufactured by Nippon Seisen Co., Ltd.). The mixture was extruded into a nozzle (degree of irregularity 6) to obtain a fibrous melt. After passing the fibrous melt as it is through a heating cylinder directly under the nozzle and cooling with cooling air, a fatty acid ester-based spinning oil agent is applied, wound around a take-up roller and stretched by a known method as it is, 470 dtex, A 144-filament approximately triangular section polyamide 66 fiber (approximately triangular section thread) was obtained. A scanning electron micrograph of the fiber cross section is shown in FIG.
The obtained substantially triangular cross section yarn was used for warp and weft, and was woven in a crank opening type water jet loom. The warp tension was adjusted to 0.30 cN / dtex, the number of wefts driven was set to 52.5 / 2.54 cm, and weaving was performed at a loom speed of 600 rpm. At this time, the protruding angle before weaving was 330 °, the weft flight was stable, and the operating rate was 98%. After weaving, it was passed through a hot water bath at 98 ° C., and the hot water treatment was performed by adjusting the processing tension so that the running tension in the warp direction was 0.027 cN / dtex (scouring treatment A). Subsequently, drying treatment was performed under running tension in the warp direction of 0.027 cN / dtex to obtain a plain weave fabric having a warp fabric density of 57 / 2.54 cm and a weft fabric density of 58 / 2.54 cm. . Table 1 shows the physical properties of the raw yarn and the physical properties of the fabric.

<Example 2>
A fiber having an atypical cross section was produced in the same manner as in Example 1 except that a nozzle with a grade 4 was used at the time of spinning, and this was woven to obtain a woven fabric. The protrusion angle before weaving was 327 °, the weft flight was stable, and the operation rate was 96%. Table 1 shows the physical properties of the raw yarn and the physical properties of the fabric.

<Example 3>
A fiber having an irregular cross section was produced in the same manner as in Example 1 except that a nozzle with an irregularity degree of 8 was used during spinning, and this was woven to obtain a woven fabric. The protrusion angle before weaving was 328 °, the weft flight was stable, and the operation rate was 97%. Table 1 shows the physical properties of the raw yarn and the physical properties of the fabric.

<Example 4>
A fiber having an irregular cross section is produced in the same manner as in Example 1 except that weaving is performed with a warp tension of 0.39 cN / dtex during weaving and a number of driven on the machine of 55.5 / 2.54 cm. This was woven to obtain a woven fabric. A plain weave fabric having a background fabric density of 60 / 2.54 cm was obtained. Table 1 shows the physical properties of the raw yarn and the physical properties of the fabric.

<Example 5>
In the same manner as in Example 1, using a nozzle with a degree of profile 6 during spinning, a triangular cross-section polyamide 66 fiber having 350 dtex and 108 filaments was obtained.
The obtained triangular cross-section yarn was used for warp and weft and woven in a crank-opening water jet loom. The warp tension was adjusted to 0.39 cN / dtex, the number of wefts driven was set to 61 / 2.54 cm, and weaving was performed at a loom speed of 600 rpm. At this time, the protruding angle before weaving was 327 °, the weft flight was stable, and the operation rate was 96%. After weaving, it was passed through a hot water bath at 98 ° C., and the hot water treatment was carried out by adjusting the processing tension so that the running tension in the warp direction was 0.027 cN / dtex. Subsequently, drying treatment was performed under running tension in the warp direction of 0.027 cN / dtex to obtain a plain weave fabric having a warp and weft fabric density of 66 / 2.54 cm. Table 1 shows the physical properties of the raw yarn and the physical properties of the fabric.

<Example 6>
A fiber having an irregular cross section was produced in the same manner as in Example 1, and this was woven in a water jet loom of a cam opening type (dwell angle 60 °). The warp tension was adjusted to 0.39 cN / dtex, the number of wefts driven was set to 56.5 / 2.54 cm, and weaving was performed at a loom speed of 600 rpm. At this time, the protruding angle before weaving was 327 °, the weft flight was stable, and the operation rate was 96%. After weaving, it was passed through a hot water bath at 98 ° C., and the hot water treatment was carried out by adjusting the processing tension so that the running tension in the warp direction was 0.027 cN / dtex. Subsequently, drying treatment was performed under running tension in the warp direction of 0.027 cN / dtex to obtain a plain weave fabric having a warp and weft fabric density of 61 / 2.54 cm. Table 1 shows the physical properties of the raw yarn and the physical properties of the fabric.

<Comparative Example 1>
Polyamide 66 resin is melt-extruded using a single-screw extruder, weighed using a gear pump, and extruded through a metal nonwoven fabric filter (NF-07, manufactured by Nippon Seisen Co., Ltd.) to a nozzle (degree of irregularity 1.0). A fibrous melt was obtained. The fibrous melt is directly passed through a heating cylinder directly under the nozzle and cooled with cooling air, and then a fatty acid ester-based spinning oil is applied, wound around a take-up roller, and stretched by a known method as it is. 470 dtex, 144 A filament round section polyamide 66 fiber was obtained.

The obtained polyamide 66 fiber was used for warp and weft and woven in a water jet loom of a cam opening type (dwell angle 60 °). The warp tension was adjusted to 0.39 cN / dtex, the number of wefts driven was set to 52.5 / 2.54 cm, and weaving was performed at a loom speed of 600 rpm. The amount of protrusion before weaving at this time was 328 °, the weft flight was stable, and the number of stops was 2 times / 100 m. After weaving, after passing through a 98 ° C. hot water tank and adjusting the processing tension so that the running tension in the warp direction is 0.027 cN / dtex, the hot water treatment is performed, and then the running tension is 0.027 cN / dtex. A drying treatment was performed under tension to obtain a plain weave fabric having a warp fabric density of 57 / 2.54 cm and a weft fabric density of 58 / 2.54 cm. Table 2 shows the properties of the raw yarn and the fabric.
Compared with the woven fabric of the example in which the cross-sectional shape of the single yarn fiber was made of a substantially triangular fiber, the woven fabric obtained in Comparative Example 1 had a high pressure permeability.

<Comparative example 2>
Except for setting the boiling water shrinkage of the polyamide 66 fiber to 6.7%, according to the procedure of Comparative Example 1, a 470 dtex, 144 filament round cross section polyamide 66 fiber was produced, and this was made into a cam opening type (dwell angle 100 °). Weaved with a rapier loom. After weaving, a plain weave fabric with a weft fabric density of 60 / 2.54 cm was obtained. Table 2 shows the properties of the raw yarn and the fabric.
Since weaving was performed with a rapier loom, the loom rotation speed was slow and the productivity of the fabric was poor. Further, even when weaving at a high density, the high-pressure air permeability was high.

<Comparative Example 3>
According to the procedure of Comparative Example 1, a 235 dtex, 36 filament round cross section polyamide 66 fiber and 235 dtex, 72 filament were produced and combined to produce a 470 dtex original yarn having two different single yarn finenesses. This was used for warps and wefts and woven in a crank opening type water jet loom. A plain weave fabric having a warp and weft fabric density of 54 / 2.54 cm was obtained. Table 2 shows the properties of the raw yarn and the fabric.
Compared to the fabric of the example in which the cross-sectional shape of the single yarn fiber was made of a substantially triangular fiber, the fabric obtained in Comparative Example 3 had a high pressure permeability. Further, when weaving at a higher density than this, yarns having different single yarn fineness were mixed, so that the yarn strength was weak, and the yarn could not be woven easily because of fluffing.

<Comparative example 4>
According to the procedure of Comparative Example 1, 470 dtex, 144 filament round cross-section polyamide 66 fiber was produced and woven in a crank opening type water jet loom. The warp tension was adjusted to 0.60 cN / dtex, the number of wefts driven was set to 52.5 / 2.54c, and weaving was performed at a loom speed of 300 rpm. At this time, the amount of protrusion before weaving was 318 °, the flying of the weft was not stable, and the number of stops was 50 times / 100 m. Table 2 shows the properties of the raw yarn and the fabric.
Compared with the woven fabric of the example in which the cross-sectional shape of the single yarn fiber was made of a substantially triangular fiber, the woven fabric obtained in Comparative Example 4 had a high pressure permeability. In addition, damage to the warp was observed, and the tensile strength in the warp direction was reduced. The occupancy rate was also bad.

<Comparative Example 5>
The hole shape of the nozzle to be used was slit, and the cross section perpendicular to the fiber axis direction was flattened by a known method, the boiling water shrinkage of the polyamide 66 fiber was 6.8%, the crank opening type A fiber was produced in the same procedure as in Comparative Example 1 except that a loom was used, and this was woven to obtain a woven fabric. The amount of protrusion before weaving at this time was 319 °, the weft run was not very stable, and the number of stops was 105 times / 100 m. Table 2 shows the properties of the raw yarn and the fabric.
The cross-sectional shape of the single yarn fiber was higher in the high-pressure air permeability than the fabric of the example made of a substantially triangular fiber. Further, the fabric of Comparative Example 5 had high high-pressure air permeability after being folded. This is presumably because the laminated structure of single yarn fibers having a flat cross section was disturbed when the woven fabric was folded. Also, the slip resistance was relatively weak.

<Comparative Example 6>
A Y-shaped polyamide 66 fiber of 470 dtex, 144 filaments was obtained according to the procedure of Comparative Example 1 except that a nozzle with a profile of 12 was used during spinning and a crank opening type loom was used. This was woven to obtain a woven fabric. At this time, the amount of protrusion before weaving was 319 °, the weft flying was not very stable, and the number of stops was 103 times / 100 m. Table 2 shows the properties of the raw yarn and the fabric.
The high-pressure air permeability was higher than that of the woven fabric of the example made of fibers having a triangular cross section.

<Comparative Example 7>
A Y-section polyamide 66 fiber of 470 dtex, 144 filaments was obtained according to the procedure of Comparative Example 1 except that a nozzle with a degree of profile 3 was used during spinning and a crank opening type loom was used. This was woven to obtain a woven fabric. At this time, the amount of protrusion before weaving was 319 °, the weft flying was not very stable, and the number of stops was 103 times / 100 m. Table 2 shows the properties of the raw yarn and the fabric.
The high-pressure air permeability was higher than that of the woven fabric of the example made of fibers having a triangular cross section.

According to the present invention, it is possible to provide a non-coated fabric for airbag having a higher density and lower air permeability and an airbag using the same.

11 A circle circumscribing the discharge hole provided in the nozzle 12 A circle inscribed in the discharge hole provided in the nozzle 13 An outer edge of the discharge hole provided in the nozzle 21, 21 ′ In a cross section orthogonal to the fiber axis direction of the single yarn fiber Vertical bisectors 22 and 22 'of straight line segments connecting the vertices of the appearing shapes Intersection points of the vertical bisectors and the outer periphery of the single yarn fiber section 31, 31' circumscribed circle 32, 32 'inscribed circle 33, 33 ′ Triangle connecting the vertices of the shape appearing in the cross section of the single yarn fiber 34, 34 ′ Perimeter of the cross section of the single yarn fiber 61 Measurement sample (fiber)
62 Teflon (registered trademark) rod having a diameter of 1 cm 63 Load 64 Binding point 65 Measurement point of the width (a) of the fiber located at the top of the Teflon (registered trademark) rod when a constant tensile tension is applied 66 Constant tensile tension Measuring point of fiber width (b) when applying 67. Bonded yarn with load using the same yarn as the measurement sample

Claims (10)

1. Including a single yarn fiber having a cross-sectional shape of approximately triangular and an irregularity of 1.3 to 2.2, a cover factor (CF) of 2050 or more and 2600 or less, and an air permeability under a differential pressure of 20 kPa is 0.25 L / cm. Non-coating fabric for airbag which is ² / min or less.
2. The non-coating woven fabric for an air bag according to claim 1, wherein the sliding resistance defined by ASTM D 6479 is an average value in a vertical direction and a horizontal direction of 700 N or more and 1200 N or less.
3. The non-coated fabric for an air bag according to claim 1 or 2, wherein the air permeability under a 20 kPa differential pressure after folding of the fabric measured by the following method is 0.30 L / cm ² / min or less.
   [Air permeability under 20 kPa differential pressure after folding fabric]
   A test piece of 20 cm square is cut out from an arbitrary place excluding the range of 30 cm from both ends in the width direction of the woven fabric, the test piece is folded in half along the fiber axis direction (a), and then in the fiber axis direction (a). Fold in half along the orthogonal fiber axis direction (b), fold again in half along the fiber axis direction (a), and half in the fiber axis direction (b) orthogonal to the fiber axis direction (a) Fold it into 5cm squares. A load of 50 N is applied to the entire surface of the folded test piece for 1 minute, and then the test piece is left for 1 minute in a state where it is spread to 20 cm square. The air permeability under a differential pressure of 20 kPa is measured using a circle having a diameter of 10 cm centering on the intersection of the first fold and the second fold as a measurement site.
4. The rate of change of the air permeability under a 20 kPa differential pressure after folding the fabric measured by the method according to claim 2 with respect to the air permeability under a 20 kPa differential pressure of the woven fabric is 150% or less. Any of the non-coating textiles for airbags.
5. The air according to any one of claims 1 to 4, wherein the total fineness of fibers constituting the woven fabric is 100 dtex or more and 600 dtex or less, the number of filaments is 40 or more and 200 or less, and the single yarn fineness is 1 dtex or more and 8 dtex or less. Non-coated fabric for bags.
6. The non-coating fabric for an air bag according to any one of claims 1 to 5, wherein the base yarn defined in 8.1 of JIS L1013 (1999) has a boiling water shrinkage of 7% or more and 12% or less and is made of nylon fiber. .
7. An airbag using the non-coated fabric for airbags according to any one of claims 1 to 6.
8. Non-airbag for airbags that use atypical fibers having a cross-sectional shape other than a round cross-sectional shape, the weft cover factor setting during weaving is 1040 or more, and the amount of protrusion before weaving on the nozzle side is 320 ° to 350 ° A method for producing a coated fabric.
9. The method for producing a non-coated fabric for an air bag according to claim 8, wherein the cross-sectional shape is a polygonal shape and the number of vertices is 3 or more and 6 or less.
10. The method for producing a non-coated fabric for an air bag according to claim 8 or 9, wherein the cross-sectional shape is a polygonal shape and the number of vertices is three.

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