JP7068633B2 - Non-coated woven fabric for airbags and airbags using it - Google Patents

Description

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

In recent years, under the influence of heightened safety awareness and changes in safety regulations, not only safety measures assuming frontal collisions such as driver airbags and passenger airbags, but also side collisions have been assumed. The adoption of curtain airbags and side airbags is increasing.

Compared to the front collision accident, the side collision accident has a closer distance between the side surface 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 suppress air leakage during deployment as much as possible. For this reason, coated fabrics with low breathability are generally used for curtain airbags and side airbags.

However, while increasing safety awareness increases the number of airbag mounting parts, there is a demand for improved fuel efficiency by reducing the weight of the vehicle body and a demand for cost reduction of assembly products to reduce the price of the vehicle body. Therefore, as a woven fabric used for an airbag (hereinafter, may be referred to as an "airbag woven fabric"), it is desired to replace a heavy and costly coated woven fabric with a non-coated woven fabric.

When considering the air permeability as an airbag, it is necessary to consider the air permeability from the airbag woven fabric which is the main body of the airbag and the air permeability from the sewn part where the airbag fabrics are sewn together. It is a non-coated woven fabric, and it is preferable to use a woven fabric woven with high density in order to keep the air permeability of the main body and the sewn part as low as possible.
The following techniques have been disclosed in the past as techniques for reducing the air permeability of airbags.

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 single yarns and reduce the air permeability.

Patent Document 2 discloses a technique for weaving a higher-density woven fabric and lowering the air permeability by weaving using a cam-driven loom.

Patent Document 3 provides a technique for providing a woven fabric for an airbag having high slip resistance and low air permeability by weaving at a high density using a single yarn fiber having a flat single yarn cross-sectional shape. Is disclosed.

Japanese Unexamined Patent Publication No. 8-325888 Japanese Unexamined Patent Publication No. 2000-328388 Japanese Unexamined Patent Publication No. 2006-16707

As described above, various methods for reducing the air permeability of the non-coated woven fabric for airbags have been studied, but the non-coated woven fabric for airbags having low air permeability that can substitute the conventional coated woven fabric has not been developed.

The present invention has focused on lowering the air permeability and increasing the density of the non-coated woven fabric for airbags, and the purpose of the present invention is to reduce air leakage as compared with the non-coated woven fabric for airbags developed by the prior art. It is an object of the present invention to provide a non-coated woven fabric for an airbag and an airbag using the non-coated woven fabric for an airbag, which can be used in a part that could not be used unless it is a coated woven fabric for an airbag in the past.

As a result of diligent research to solve the above problems, the present inventors have been able to weave a non-coated woven fabric for an airbag containing fibers having a substantially triangular cross section having a specific degree of atypia in the weaving yarn at a high density. We have found that the air permeability is lower than that of the conventional non-coated woven fabric and the sliding resistance value is high, and the present invention has been completed. The present invention has the following configuration.
(1) A single yarn fiber having a substantially triangular cross-sectional shape and a degree of atypia of 1.3 to 2.2 is included, a cover factor (CF) is 2050 or more and 2600 or less, and the air permeability under a differential pressure of 20 kPa is 0. Non-coated woven fabric for airbags of 25 L / cm ² / min or less.
(2) The non-coated woven fabric for airbags according to (1), wherein the slip resistance force defined by ASTM D 6479 is 700 N or more and 1200 N or less on average in the vertical and horizontal directions.
(3) The non-coated woven fabric for airbags according to (1) or (2), wherein the air permeability under a differential pressure of 20 kPa after folding, which is measured by the following method, is 0.30 L / cm ² / min or less. ..
[Air permeability under 20 kPa differential pressure after folding the woven fabric]
A 20 cm square test piece is cut out from an arbitrary location excluding a range of 30 cm from both ends in the width direction of the fabric, the test piece is folded in half along the fiber axial direction (a), and then in the fiber axial direction (a). Fold in half along the orthogonal fiber axis direction (b), fold in half again along the fiber axis direction (a), and halve along the fiber axis direction (b) orthogonal to the fiber axis direction (a). Fold it in 5 cm square. A load of 50 N is applied to the entire surface of the folded test piece for 1 minute, and then the folded test piece is left unfolded in 20 cm square for 1 minute. The air permeability under a differential pressure of 20 kPa is measured with a circle having a diameter of 10 cm centered at the intersection of the first fold and the second fold as the measurement site.
(4) The rate of change of the air permeability under the 20 kPa differential pressure after folding of the woven fabric measured by the method according to (2) with respect to the air permeability of the woven fabric under the differential pressure of 20 kPa is 150% or less (1). The non-coated woven fabric for airbags according to any one of (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. Non-coated woven fabric for airbags described in Crab.
(6) The boiling water shrinkage rate of the raw yarn defined in 8.1 of JIS L1013 (1999) is 7% or more and 12% or less, and the raw yarn is one of (1) to (5) made of nylon fiber. The listed non-coated fabric for airbags.
(7) An airbag using the non-coated woven fabric for an airbag according to any one of (1) to (6).
(8) Air using irregular fibers whose cross-sectional shape is other than the round cross-sectional shape, the setting of the cover factor of the warp and weft at the time of 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 manufacturing non-coated woven fabrics for bags.
(9) The method for manufacturing a non-coated woven fabric for an airbag 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 manufacturing a non-coated woven 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.

Since the non-coated woven fabric for airbags of the present invention contains substantially triangular cross-section fibers having a specific degree of atypia in the weaving yarn, it can be woven at high density, has lower air permeability than the conventional non-coated woven fabric, and has slip resistance. It is possible to exhibit the characteristics with high value.

It is a figure which shows the nozzle which has the irregular cross section, and how to obtain the irregularity degree. It is a cross-sectional schematic diagram which shows an example of a preferable cross-sectional shape of a single yarn fiber, and how to obtain the degree of deformation of the cross section of the single yarn fiber. It is sectional drawing which shows the cross-sectional shape of another single yarn fiber, and how to obtain the degree of deformation of the cross section of the single yarn fiber. It is a scanning electron micrograph which shows the cross section of the single yarn fiber obtained in Example 1. FIG. It is a scanning electron micrograph which shows the cross section of the single yarn fiber obtained in the comparative example 3. FIG. It is a schematic diagram of the measuring method of a yarn widening ratio.

The non-coated woven fabric for an airbag of the present invention contains a single yarn fiber having a substantially triangular cross-sectional shape and a degree of atypia of 1.3 to 2.2, and has a cover factor (CF) of 2050 or more and 2600 or less, and 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 present inventors have increased the density by weaving woven fabrics for airbags using substantially triangular cross-section fibers having a specific degree of deformation instead of the conventionally used fibers such as round cross-sections and irregular cross-sections. The present invention has been completed by finding that a woven fabric that can be woven, has a lower air permeability than a conventional non-coated woven fabric, and has a high slip resistance value can be obtained. Hereinafter, the present invention will be described in detail.

The material of the fiber constituting the non-coated woven fabric for an airbag of the present invention is not particularly limited, but for example, an aliphatic polyamide fiber such as nylon 66, nylon 6, nylon 46 and nylon 12, and an fragrance such as aramid fiber. Examples thereof include polyester fibers such as group polyamide fibers, polyethylene terephthalates, polytrimethylene terephthalates and polybutylene terephthalates. Further, total aromatic polyester fiber, ultra-high molecular weight polyethylene fiber, polyparaphenylene / benzobis / oxazole fiber (PBO fiber), polyphenylene sulfide fiber, polyether ketone fiber and the like can also be used. However, polyester fiber and polyamide fiber are preferable in consideration of economic efficiency, and nylon 66 made of polyhexamethylene adipamide fiber is preferable from the viewpoint of durability against high temperature gas.

When nylon 66 is used as a constituent fiber of a non-coated woven 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. It is more preferably 3.3 or more, and even more preferably 3.4 or more. However, if the relative viscosity is too high, not only the polymerization cost increases, but also the spinning operability tends to deteriorate. Therefore, the relative viscosity is preferably 3.6 or less, more preferably 3.5 or less.

As the fibers constituting the woven fabric, fibers obtained from raw materials recycled from waste plastic materials may be used for a part or all of them. Further, the material constituting the fiber may contain various additives for improving the process passability in the manufacturing process. Examples of the additive include antioxidants, heat stabilizers, smoothing agents, antistatic agents, thickeners, flame retardants and the like. Further, the fibers constituting the airbag woven fabric may be dyed after the original yarn or the silk reeling.

In the non-coated woven fabric for an airbag of the present invention, it is important to use a single yarn fiber having a substantially triangular cross-sectional shape orthogonal to the fiber axis direction (hereinafter, may be simply referred to as a substantially triangular cross-sectional fiber).
By using a fiber having a substantially triangular cross-sectional shape, the single yarn fiber can be woven at a high density on a loom, and a woven fabric having low air permeability can be obtained. The present inventors consider the reason as follows. The reason why a fiber having a substantially triangular cross-sectional shape exhibits high density and low air permeability because the single thread fiber moves and is filled in a fine state when an external force is applied to the fiber. It can be considered as one of.
That is, as a result of the single yarn fibers being finely filled with the external force applied when the weft is driven with a reed on the loom or when the weft is restrained by the warp, the fibers having a gap between the single yarn fibers are compared with the fibers having a gap between the single yarn fibers. Even if the fineness is the same, the actual fiber diameter is smaller, so it is presumed that weaving can be performed at a higher density on the loom. In addition, the air permeability is lower than that of conventional woven fabrics because the woven fabric can be woven at high density and the voids between the fibers during ventilation are reduced, and the single yarn fibers are finely filled with the pressure applied during ventilation. This is thought to be because the air permeability inside the fiber also decreases as a result of the decrease in the voids inside the fiber.

The reason why the single yarn fiber moves due to the external force as described above is that when the shape appearing in the cross section orthogonal to the fiber axis direction of the single yarn fiber is substantially triangular, the cross-sectional shape is compared with other polygonal fibers. The number of vertices is small, and the single yarns are less likely to get caught.

The single yarn fiber used in the present invention has a degree of atypia of 1.3 or more and 2.2 or less. The degree of atypia is used as an index of the atypical shape of the cross section of the single yarn fiber. Theoretically, it is preferable that the cross-sectional shape is 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, so the cross-sectional shape of the single yarn fiber is different. The vertices have a rounded shape. Therefore, the most preferable degree of atypia in the present invention is around 1.6. The degree of atypia 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 deformation is too small, gaps may be formed between the single yarn fibers to reduce the air permeability of the woven fabric, and at the same time, the movement of the single yarn fibers may be suppressed. On the other hand, if the degree of deformation is too large, the unevenness of the fiber surface becomes large and catches between adjacent fibers, which may also make it difficult for the single yarn fibers to move.
The change in the degree of deformation before and after weaving is small, and the single yarn fiber after weaving usually has the same degree of deformation as the single yarn fiber (raw yarn) before weaving. Therefore, it is preferable that the degree of deformation of the unwoven yarn taken out from the woven fabric is also within the above range. The degree of deformation of the cross section of the single yarn fiber is determined by the method described in Examples.

As shown in FIG. 2, the single-thread fiber according to the present invention connects the vertices (a, b, c) of substantially triangles (outer circumference of the single-thread 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 circumference 34 of the single yarn fiber cross section. 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 circumference 34 of the cross section of the single yarn fiber. This relationship is related to the intersection 22 of the perpendicular bisector 21 of the line segments ab, bc, and ca connecting the vertices a, b, and the outer circumference 34 of the single yarn fiber cross section and the outer circumference 34 of the single yarn fiber cross section. Is synonymous with being located outside the triangle 33. Ideally, the single yarn fiber according to the present invention has an equilateral triangle shape that appears in a cross section orthogonal to the fiber axis direction. In this case, the triangle 33 coincides with the outer circumference 34 of the cross section of the single yarn fiber.

On the other hand, for example, the shape 34'appearing in the cross section orthogonal to the fiber axis direction and the apex (a', b', of the shape 34', even if the fiber has a certain degree of atypicality like the fiber shown in FIG. When the straight line connecting c') (for example, a'b') and / or the shape (triangle 33') does not have the above-mentioned relationship, that is, when 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-thread fibers is close to a Y-shape), and the amount of voids between the single-thread fibers is large, so that not only the air permeability is high, but also the inside of the fibers (multifilament) The single yarn fiber tends to be difficult to move.

In order to obtain a single yarn fiber that easily moves in the multifilament by an external force, it is preferable to reduce the degree of entanglement of the fiber. It is preferable that the number of entanglements in the raw yarn production stage is 5 pieces / m or more and 30 pieces / m or less in order to perform high-density weaving. The degree of entanglement of the yarns at the stage of unwoven from the woven fabric is preferably 20 yarns / m or less, more preferably 15 yarns / m or less, and further preferably 8 yarns / m or less on the average value of the warp and weft yarns. There is no particular lower limit, and the degree of entanglement may be 0 / m. When the degree of entanglement is within the above range, the movement of single yarn fibers is not easily hindered, and a high-density, low-ventilation non-coated woven fabric for airbags can be obtained. The degree of entanglement at 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 degree of entanglement is more preferably 28 pieces / m or less, still more 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 ratio of the yarns (fibers) taken out by unweaving the non-coated woven fabric for airbags. Therefore, in the present invention, the widening ratio of the yarn is moved so that the single yarn fibers are most densely filled in the fibers by an external force such as tension, and the single yarn fibers are displaced at the interface with the adjacent single yarn fibers. Therefore, it is used as an index showing how the fiber moves in the 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 an external force.

The widening ratio of the fibers taken out by uncoating the non-coated woven fabric for airbags is preferably 2.4 or more and 3.5 or less. When the widening ratio of the yarn is less than 2.4, the single yarn fibers are difficult to move, and when an external force is applied to the fibers, the single yarn fibers are difficult to be finely filled and it is difficult to weave at a higher density. Tend to be. Therefore, the widening ratio of the yarn is more preferably 2.5 or more, still more preferably 2.6 or more. If the widening ratio of the yarn is higher than 3.5, the single yarn fibers may move too easily, and it may not be possible to maintain a state in which the gaps between the single yarn fibers are tightly closed, resulting in high air permeability. More preferably, it is 3.4 or less. The widening ratio of the yarn is obtained by the measuring method described later.

The mechanical properties of the fibers constituting the non-coated woven fabric for airbags are preferably 7.0 cN / dtex or more, more preferably more preferably, from the viewpoint of satisfying the mechanical properties required for airbags. It is 7.5 cN / dtex or more. Higher cutting strength is preferable, but 9.5 cN / dtex or less is preferable, and 9.0 cN / dtex or less is more preferable in consideration of yield at the time of production.

The single yarn fineness of the filament constituting the fiber is preferably 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 decreases, so that the air permeability inside the fibers becomes high, and it may be difficult to obtain a low-ventilation airbag. On the other hand, if the single yarn fineness is too small, the productivity of the fiber may decrease. It is more preferably 2 dtex or more and 7.5 dtex or less, and further preferably 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 becomes high, and it tends to be difficult to obtain a low-ventilation airbag. On the other hand, when the number of filaments exceeds 200, the productivity of the fibers tends to decrease. The number of filaments is more preferably 50 or more, further preferably 60 or more, still more preferably 180 or less, 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 preferable. If the total fineness is less than 100 dtex, there is a possibility that the tensile strength and the tear strength will be insufficient when the woven fabric for airbags is used. On the other hand, if it exceeds 600 dtex, a strength problem is unlikely to occur, but the flexibility required for the airbag is impaired, and the surface of the fabric becomes hard, which may damage the skin of the human body at the time of collision. ..

The structure of the non-coated woven fabric for airbags is not particularly limited, but plain weave is preferable in consideration of the uniformity of the woven fabric properties. The warp and weft do not have to be the same as the weaving yarn, and the thickness, the number of yarns, the type of fiber, and the like may be different as long as the strength and air permeability that satisfy the performance as an airbag can be obtained. From the viewpoint of making a woven fabric with low air permeability, the above-mentioned cross-sectional shape is substantially triangular in 100% of the fibers constituting the non-coated woven fabric for airbags (total of warp and weft), and has a specific degree of atypia. It is preferable to use 25% or more of fibers (multifilaments) containing single yarn fibers. It is more preferably 50% or more, and most preferably 100%.

The non-coated fabric for airbags 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 tension applied to the warp during weaving may damage the warp and cause fluffing, making it difficult to weave at high density. Further, if it is less than 2050, it may be difficult to obtain the low air permeability required for an airbag. The cover factor is more preferably 2200 or more and 2500 or less.
CF = (warp density [book / 2.54 cm]) x √ (warp fineness [dtex] x 0.9) + (weft density [book / 2.54 cm] x √ (weft fineness [dtex] x 0.9)) ) (Equation 1)

The non-coated fabric for airbags has an air permeability (high pressure air permeability) of 0.25 L / cm ² / min or less under a differential pressure of 20 kPa. If the high-pressure air permeability exceeds 0.25 L / cm ² / min, the low air permeability required for an airbag cannot be ensured. The high-pressure air permeability is more preferably 0.20 L / cm ² / min or less, and further preferably 0.15 L / cm ² / min or less.

Further, the non-coated fabric for airbags preferably has a high-pressure air permeability (air permeability under a differential pressure of 20 kPa) of 0.30 L / cm ² / min or less after being folded by a predetermined method. Since the airbag fabric is stored in a predetermined place in the vehicle in a folded or randomly compressed state, it is difficult to secure the internal pressure required for restraining the occupant when the airbag is deployed if the air permeability after folding is high. Tend to be. The high-pressure air permeability after folding is more preferably 0.25 L / cm ² / min or less, and further preferably 0.20 L / cm ² / min or less. The high-pressure air permeability after folding of the airbag woven fabric is determined by the method described in the examples.

Further, the non-coated fabric for airbags preferably has an air permeability change rate (formula 2 below) represented by the ratio of 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 required to restrain the occupant when the airbag is deployed. It is more preferably 130% or less, still more preferably 120% or less.
Air permeability change rate (%) = (High-pressure air permeability after folding) / (High-pressure air permeability before folding) x 100 (Equation 2)

The non-coated fabric for airbags preferably has a slip resistance defined by ASTM D6479 having an average value of 700 N or more and 1200 N or less in the vertical direction and the horizontal direction. If the slip resistance is less than 700 N, the sewn portion will open when the airbag is unfolded, and the air permeability of the airbag will deteriorate, which is not preferable. On the other hand, if the slip resistance exceeds 1200 N, the woven fabric becomes rigid, which impairs the flexibility required for the airbag and hardens the surface of the fabric, which may damage the skin of the human body at the time of collision. be. It is more preferably 750 N or more and 1100 N or less, and further preferably 800 N or more and 1050 N or less.

Next, the fiber used for the non-coated woven fabric for airbags of the present invention and the method for manufacturing the non-coated woven fabric for airbags using the fiber will be described.
The fibers constituting the non-coated woven fabric for airbags may be manufactured according to a conventional method. For example, the raw material resin is melt-extruded using a single-screw or twin-screw extruder, weighed using a gear pump, extruded to a nozzle through an appropriate metal non-woven fabric filter to form a fibrous melt, and then fibrous melt. The material can be made into a filament by passing the material as it is through a heating cylinder directly under the nozzle, cooling it with cooling air, applying a spinning oil, winding it around a take-up roller, stretching it as it is, and then performing an entanglement treatment.

As described above, the fibers constituting the non-coated woven fabric for airbags of the present invention need to have a substantially triangular cross-sectional shape and have a specific degree of atypia. In order to obtain such fibers, it is preferable to spin 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 three discharge holes 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. Method of forming into 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. A method of discharging the molten resin from a nozzle having a discharge hole shape in which adjacent substantially isosceles triangles are arranged so as to share the end of the bottom can be mentioned.

Since the degree of deformation of the fiber cross section is greatly affected by the degree of deformation of the nozzle, a nozzle having a discharge hole shape as shown in FIG. 1 is used in order to obtain a fiber having a substantially triangular cross section shape having a specific degree of deformation. Is preferable. By using the nozzle having this shape, it becomes easy to adjust the degree of deformation of the fiber cross section.
The degree of atypia of the nozzle is preferably 2 or more and 10 or less, and more preferably 3 or more and 8 or less. If the degree of nozzle deformation is too small, the fiber cross section after silk reeling tends to have a shape close to a round cross section. On the other hand, if the degree of deformation of the nozzle is too large, the fiber cross section after spinning tends to have a flat shape or a shape close to a Y shape.

The degree of deformation of the nozzle can be expressed by the ratio of the radius of the circumscribed circle and the inscribed circle of the nozzle hole (radius of the circumscribed circle / radius of the inscribed circle). More specifically with reference to FIG. 1, the circumscribed circle 11 is represented by a broken line in FIG. 1 and is a circle passing through the vertices A, B, and C of the outer edge 13 of the discharge hole of the nozzle. On the other hand, the inscribed circle 12 is represented by a chain line in FIG. 1, and when the discharge hole is regarded as a shape consisting of three substantially isosceles triangles having the vertices A, B, and C, adjacent isosceles triangles. It is a circle passing through the intersections D, E, and F of the equilateral sides of.

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

In order to make the temperature of the nozzle surface uniform, a device such as a heat insulating cylinder or a heating cylinder may be installed between the nozzle and the winding roll for winding the fiber. The length of the heat insulating cylinder or the heating cylinder is preferably in the range of, for example, 2 cm or more and 50 cm or less from the nozzle. If the length of the heating cylinder is shorter than 2 cm, the cooling air in the subsequent cooling step may enter, the temperature of the nozzle surface may become 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, so-called resonance, which is called periodic longitudinal thread spots, tends to occur easily.

The temperature of the cooling air used to cool the molten yarn is preferably in the range of 15 ° C. or higher and 30 ° C. or lower. If the temperature of the cooling air is lower than 15 ° C, there is a risk that the difference in physical properties such as atypia and strength between the fibers will be large, while if the temperature of the cooling air is higher than 30 ° C, the atypia of the fiber cross section may become too small. There is. It is more preferably 18 ° C. or higher and 28 ° C. or lower, and further preferably 20 ° C. or higher and 25 ° C. or lower.

The wind speed of the cooling air is preferably in the range of 0.1 m / sec or more and 1 m / sec or less. If it is less than 0.1 m / sec, it may be difficult to sufficiently cool the filaments, and there is a possibility that fineness spots are likely to occur between the fibers. On the other hand, when the wind speed exceeds 1 m / sec, the cooling speed tends to be different between the upstream side and the downstream side of the cooling air, and there is a possibility that fineness spots may occur between the fibers.

Further, when winding the cooled yarn, it is preferable that the draft ratio calculated from the following formula 3 is 100 or more and 150 or less.
Draft ratio = Pick-up roller speed [m / min] / (single hole volume discharge amount [m ³ / min] / nozzle hole cross-sectional area [m ² ]) (Equation 3)
When the draft ratio is smaller than 100, the yarn sway becomes large, and there is a tendency that fusion between fibers and yarn breakage are likely to occur. On the other hand, when the draft ratio is larger than 150, the alignment spots of the molecular chains in the cross section of the single yarn fiber, particularly the difference in the alignment of the molecular chains between the central part of the cross section and the vicinity of the apex of the substantially triangle becomes large, and there are problems such as a decrease in strength. Tends to occur easily.

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, alignment spots of molecular chains occur in the cross section of the filament, cracks are likely to occur in the filament, the strength of the fiber is lowered, and yarn breakage is likely to occur during fiber production. There is a risk.

The temperature at the time of stretching is preferably in the range of 20 ° C. or higher and 240 ° C. or lower, although it depends on the subsequent weaving method. If the stretching temperature is lower than 20 ° C., yarn breakage may occur before the required stretching ratio is reached. On the other hand, when the stretching temperature exceeds 240 ° C., the yarn tends to be melted and stretching tends to be difficult.

In the fiber used for the non-coated woven fabric for airbags of the present invention, it is preferable to keep the entanglement by fluid treatment such as air pressure, so-called interlace treatment, to the minimum necessary. Specifically, the degree of entanglement of the fibers at the raw yarn stage is preferably 5 pieces / m or more and 30 pieces / m or less. In order to keep the degree of entanglement within the above range, it is preferable to perform an interlace treatment after the end of the drawing treatment and before winding to adjust the degree of entanglement of the fibers.

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

In the fiber used for the non-coated woven fabric for airbags of the present invention, the boiling water shrinkage rate is not particularly limited, but the boiling water shrinkage rate is set to 7% or more and 12% or less in order to increase the sliding resistance of the airbag woven fabric. It is preferable to do so. If the boiling water shrinkage rate is too small, there is a risk that the slip resistance will be reduced because the fibers are less tightly tightened when processing is performed in the manufacturing process of the airbag woven fabric. On the other hand, if the boiling water shrinkage rate is too large, the stability of the fiber over time is poor, which causes a large variation in the physical characteristics of the woven fabric depending on the storage period, which is not preferable. It is more preferably 8% or more and 11% or less, and further preferably 8.5% or more and 10% or less.

The method for weaving a non-coated fabric for an 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. It is more preferably 0.15 cN / dtex or more and 0.4 cN / dtex or less, and further preferably 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 at a high density, and the degree of entanglement of the warps tends to be maintained, and the low air permeability required for an airbag when woven is used. It may be difficult to obtain sex. If it is higher than 0.5 cN / dtex, the force applied to the warp may be too large and fluff may occur.

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

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

When weaving a non-coated fabric for airbags, the loom rotation speed is preferably 400 rpm or more and 1000 rpm or less. If the loom rotation speed is too slow, productivity is impaired, which is not preferable. On the other hand, if the loom rotation speed is too fast, stable and high-density weaving becomes difficult, which is not preferable. It is more preferably 500 rpm or more and 900 rpm or less, and more preferably 550 rpm or more and 800 rpm or less.

When weaving non-coated fabrics for airbags, it is very important to allow the wefts to fly stably in order to improve weaving efficiency. In order to realize stable weft flight, one condition is that an opening area created by the warp being separated up and down is sufficiently secured when the weft is inserted, but the woven fabric is woven at a higher density. In this case, weaving becomes difficult because the weaving front from the temple that grips the woven fabric protrudes and the opening area is not sufficiently secured.

The non-coated woven fabric for airbags containing substantially triangular cross-sectional fibers according to the present invention can be woven while suppressing protrusion before weaving, so that weaving efficiency can be improved even when weaving under higher density conditions. The inventors have found that it can be maintained at the same level as time. That is, the substantially triangular cross-sectional fibers of the present invention are finely filled between the single yarn fibers by the external force applied when the weft yarns are driven with a reed on the loom or when the weft yarns are restrained by the warp yarns, and as a result, between the single yarn fibers. Compared to fibers with gaps, the actual fiber diameter is smaller even if the fineness is the same, so it is presumed that weaving can be performed at a higher density on a loom.

In order to suppress the amount of protrusion even when weaving at a higher density than in the past, it is necessary to take a form in which the fibers are finely packed without gaps between the single yarn fibers when they receive an external force. Therefore, the amount of protrusion is not limited to the substantially triangular cross-section fiber, and polygonal shapes such as a regular hexagonal shape and a regular square shape, and other shapes such as a rhombus can be considered. However, the substantially triangular cross-section fiber shape of the present invention is preferable from the viewpoints of ease of movement of the fibers constituting the woven fabric, low air permeability of the woven fabric, and maintenance of low air permeability even after folding.

In particular, in the case of high-density weaving in which the cover factor (cf) of the warp and weft obtained by the following formula 4 is 1040 or more at the time of weaving, it is preferable to use atypical fibers typified by substantially triangular cross-section fibers. In the case of exhibiting the characteristics of high density and low air permeability, 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 if the shape is a rhombus shape biased into a square shape. However, the more vertices of the polygonal shape, the closer to the round cross section, and the more complicated the shape, the more easily gaps are created between the single yarn fibers when an external force is applied. Therefore, the number of vertices is 3 or more and 6 or less. Is preferable. It is more preferably 3 or more and 4 or less, and further preferably 3 substantially triangular cross-section fibers.
Weft cf = (Weft driving setting [book / 2.54 cm]) x √ (Weft fineness [dtex] x 0.9) (Equation 4)

As one index for checking that the opening area is sufficiently secured, there is a method for checking the amount of protrusion of the selvage. The amount of protrusion of the selvage tends to increase as compared with the central part of the woven fabric, which is also a factor that hinders the stable flight of the weft.
The reason why the amount of protrusion differs between the ears and the center of the woven fabric is that in the center of the woven fabric, tension is applied to the wefts along the fiber axis by the adjacent warps, so that crimps of the warps are strongly formed, but both ears. Then, since there is no warp on one side, the warp is loosened and the crimp of the warp is weakly formed, which is presumed to be the result of a difference in the length of the warp between the central part of the woven fabric and the ear part.

The amount of protrusion measured by the predetermined method shown in the examples is preferably 320 ° or more and 350 ° or less. In this measurement using a strobe, the point where the reed is completely driven is set to 0 ° = 360 °, and the time when the reed hits the weaving protrusion on the nozzle side after the weft is driven is recorded. It is an index that the smaller the amount, the larger the amount of protrusion. If the amount of protrusion is smaller than 320 °, the opening region is not sufficiently secured, the flight of the weft is not stable, and the weaving efficiency is not improved, which is not preferable. When the amount of protrusion is larger than 350 °, it is an area where weaving is virtually impossible as a high-density woven fabric. It is more preferably 325 ° or more and 340 ° or less, and further preferably 327 ° or more and 335 ° or less.

As an index showing weaving efficiency, there is the number of stops for weft driving. As mentioned above, if stable weft flight is not realized due to unreasonable high density, or if weaving conditions such as warp tension and weaving machine timing are not set properly, weft driving cannot be performed and the loom will not be able to drive. It will stop. When weaving a woven fabric for airbags, the number of stops for weft driving is preferably 4 times / 100 m or less. If the vehicle is stopped any longer, the production efficiency will drop, which is not preferable. It is more preferably 3 times / 100 m or less, and further preferably 2 times / 100 m or less.

The processing method after weaving the non-coated fabric for airbags is not particularly limited. Therefore, any processing may be performed as long as the above-mentioned characteristic of the present invention, that is, the characteristic that the single yarn fiber moves in the woven fabric due to the influence of an external force can be maintained. Examples of the processing method for the non-coated fabric for airbags after weaving include heat treatment such as scouring treatment, drying, and heat setting. These may be carried out individually or in combination of two or more.
Specifically, as a mode of combining the processing methods of the woven fabric after weaving, a mode in which the raw machine woven in the water jet room is naturally dried or subjected to a heat treatment process for drying; the raw machine woven by various weaving machines is used in the scouring process. Examples thereof include a mode in which the raw machine woven by various weaving machines is subjected to a scouring step and then subjected to a heat treatment step for heat setting; and the like. Of course, the woven fabric (raw machine) as it is woven on the loom may be cut and sewn as it is without being subjected to the above-mentioned processing process to form an airbag.

First, an embodiment in which a raw machine woven in a water jet room is naturally dried or subjected to a heat treatment step for drying will be described (hereinafter, may be referred to as a first aspect). When the heat treatment step at a specific temperature is carried out, the heat treatment temperature (drying temperature) of the living machine is set to 20 ° C. or higher and 190 ° C. or lower. It is preferably 40 ° C. or higher and 160 ° C. or lower, and more preferably 60 ° C. or higher and 140 ° C. or lower. The heat treatment time (drying time) is preferably 10 seconds or more and 5 minutes or less. It is more preferably 20 seconds or more and 3 minutes or less, and further preferably 30 seconds or more and 2 minutes or less. In the heat treatment step, it is sufficient that the raw machine can be heat-treated at the above temperature, and the method is not particularly limited. Therefore, the apparatus for carrying out the heat treatment step is not particularly limited, and is an apparatus used for drying textiles, for example, a dryer using hot air as a heating medium (dryer type heating furnace), a cylinder dryer using hot air, steam, etc. as a heating medium, and the like. Any of these can be used. Further, in the first aspect, instead of the heat treatment step, the raw machine after weaving may be naturally dried to complete the airbag woven fabric.

In the embodiment in which the raw machine woven by various looms is subjected to a scouring step and then subjected to a heat treatment step for drying (hereinafter, may be referred to as a second aspect), after weaving, the raw machine is heated to 50 ° C. or higher and 100 ° C. or lower. Apply hot water treatment to pass through the water tank (refining process). In the hot water treatment, the woven fabric is shrunk while removing the oil agent, the sizing agent, etc. added in the spinning process and the weaving process from the woven fabric. If the temperature of the water is less than 50 ° C., it may be difficult to sufficiently shrink the woven fabric. The temperature of water is more preferably 60 ° C. or higher and 98 ° C. or lower, and even more preferably 70 ° C. or higher and 95 ° C. or lower. The hot water treatment is preferably carried out for 10 seconds or more and 3 minutes or less. It is more preferably 20 seconds or more and 2 minutes or less, and further preferably 30 seconds or more and 1 minute or less. As the water used in the hot water treatment, in addition to tap water and pure water, an aqueous solution in which one or more of a surfactant such as sodium alkylbenzene sulfonic acid, an alkaline scouring agent such as soda ash, an enzyme, or an organic solvent is dissolved is used. You may use it.

Further, it is preferable to carry out the hot water treatment while applying a tension of 0.040 cN / dtex or less in the warp direction of the raw machine. By carrying out the hot water treatment under a predetermined tension, the yarns in the raw machine can be rearranged by sufficiently shrinking the woven fabric. Further, when a polyamide fiber such as nylon 66 is used, hydrogen bonds in the fiber are more easily 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, it becomes difficult for the woven fabric to contract freely during hot water treatment, and the woven fabric itself becomes close to being heat-fixed in a tense state, so that the single yarn fibers tend to move easily. It may be easily damaged.

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

In a mode in which a raw machine woven by various looms is subjected to a scouring step and then subjected to a heat treatment step for heat setting (hereinafter, may be referred to as a third aspect), relatively low temperature water is used in the scouring step. Specifically, water having a temperature of 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. Within the above temperature range, the oil agent, sizing agent and the like added in the spinning process and the weaving process can be efficiently removed from the woven fabric.

As long as water having a specific temperature is used, the refining process is not limited, and a conventionally known refining method can be adopted. As the water used in the scouring process, in addition to tap water and pure water, an aqueous solution in which one or more of a surfactant such as sodium alkylbenzene sulfonic acid, an alkaline scouring agent such as soda ash, an enzyme, and an organic solvent are dissolved is used. You may use it.

Further, the scouring step may be carried out while applying tension in the traveling direction of the raw machine and the direction orthogonal to the traveling direction (width direction). For example, the overfeed rate in the traveling direction of the raw 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 raw 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. be.

The scouring treatment is preferably carried out for 10 seconds or more and 5 minutes or less. It is more preferably 20 seconds or more and 3 minutes or less, and further preferably 30 seconds or more and 2 minutes or less. The woven fabric (raw machine) after the scouring treatment may be subjected to a heat treatment step after being dehydrated or dried once. The woven fabric after the scouring treatment may be directly subjected to the heat treatment step.

Next, the woven fabric after the scouring treatment 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, still more preferably 175 ° C. or lower. If the heat treatment temperature is too low, it tends to take a long time to dry the woven fabric wet by the scouring process, which is not efficient and the shrinkage force inherent in the fibers is not sufficiently exerted between the fibers. There is a risk that the mesh size will become large and the air permeability will increase. On the other hand, if the heat treatment temperature is too high, not only the fibers constituting the woven fabric may be thermally deteriorated and the mechanical strength may be lowered, but also strong tension is given to the woven fabric due to the heat shrinkage, and the woven fabric is hardened. , There is a possibility that the property that the single yarn fiber is easy to move is easily impaired.

In the third aspect, the heat treatment is performed while applying tension to the fabric (heat set). 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 have an overfeed. The overfeed rate in the traveling direction of the woven fabric is 1.5% or more and 6.0% or less, preferably 2.0% or more and 5.0% or less, and more preferably 2.5% or more and 4.5% or less. Is. On the other hand, the overfeed rate (width filling rate) in the direction orthogonal to the traveling direction (width direction) of the woven fabric is 1.0% or more and 4.0% or less, preferably 1.5% or more and 3.5% or less. It is more preferably 2.0% or more and 3.0% or less.
When the raw machine is supplied in an overfeed state in both the scouring process and the heat treatment (heat setting) process, the overfeed rate in the traveling direction of the fabric should be 0% or more and 5.0% or less in the heat setting process. Is preferable, 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 traveling direction (width direction) of the fabric 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 traveling direction of the woven fabric is a value expressed by the following equation 5. Overfeed by making the speed of the feed roller (V ₁ ), which is on the upstream side of the heat treatment process and supplies the fabric to the heat treatment process, faster than the speed of the take-up roller (V ₂ ), which is on the downstream side of the heat treatment process. Can be in a state.
Overfeed rate in the traveling direction (%) = (V ₁ / V ₂ ) x 100 (Equation 5)
[V ₁ : Feed roller speed, V ₂ : Take-up roller speed]

On the other hand, the overfeed rate in the direction (width) orthogonal to the traveling direction of the woven fabric is a value represented by the following equation 6. Normally, the heat treatment step is carried out with both ends in the width direction of the woven fabric fixed, but the distance from one fixed end to the other end is made narrower than the width of the woven fabric before the heat treatment step is supplied. It can be in an overfeed state.
Overfeed rate (%) in the direction orthogonal to the running direction of the woven fabric = (1-L ₀ / L ₁ ) × 100 (Equation 6)
[L ₀ : Width of the woven fabric before being supplied to the heat treatment step (m), L ₁ : Width of the woven fabric after being supplied to the heat treatment step (m)]

When the overfeed rate in the traveling direction and the width direction of the woven fabric is within the above range, the movement of the single yarn fiber when the woven fabric receives an external force and the spreading of the weaving yarn in the direction orthogonal to the fiber axis are preferably generated. Therefore, it is preferable. If the overfeed rate is too small, the yarn shrinks due to heat treatment and excessive tension is applied to the single yarn fiber itself, which makes it difficult for the single yarn fiber to move even when an external force is applied, or weaves in the direction perpendicular to the fiber axis. There is a risk that the yarn will not spread easily and the air permeability will increase. Further, 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.

The heat setting may be carried out by using a known device and a heating means in combination. Examples of such a device include a device for holding a woven fabric called a pin tenter or a clip tenter. 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-mentioned non-coated woven fabric for an airbag so as to have a desired shape.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples as well as the present invention, and appropriate modifications are made to the extent that it can meet the purposes of the preceding and the following. Of course, it is possible to carry out, and all of them are included in the technical scope of the present invention.

(1) Total fineness Measured according to JIS L1095 9.4.1.

(2) Number of filaments Calculated according to 8.4 of JIS L1013 (1999).

(3) Strength and elongation JIS L1017 8.5 a) According to the definition of standard time test, after leaving for 24 hours in a room where temperature and humidity are controlled at 20 ° C and 65% RH, a tensile tester (manufactured by Orientec Co., Ltd.) Strength and elongation were obtained by "Tensilon universal material tester").

(4) Boiling water shrinkage rate The measurement was performed by (a) skein shrinkage rate (method A) described in 8.18.1 of JIS L1013 (1999).

(5) Weaving density (number of driving)
The measurement was performed according to 8.6 of JIS L1096 (1999).

(6) Cross-sectional shape and degree of atypia Using a scanning electron microscope, the cross-sections of five arbitrarily selected fibers are photographed (magnification 1000 to 2000). Using commercially available software (for example, NIS-Element's Division), select three points (referred to as a, b, c) of the vertices of substantially triangles that visually appear in the cross section of the fiber in the cross-sectional photograph of the obtained fiber. A circle that passes through the points a, b, and c and circumscribes the cross section of the fiber is drawn (circumscribed circle 31). Next, a vertical bisector 21 of the line segments ab, bc, and ac connecting the vertices is drawn, passes through the three intersections 22 of the fiber cross section intersecting the vertical bisector 21, and is inscribed in the fiber cross section. Draw a circle (inscribed circle 32). Then, the 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 atypia (see FIGS. 2 to 5). The average value of 5 filaments was used as the degree of atypia. The degree of atypia of the nozzle hole was also calculated by the same method.
When the cross-sectional shape of the fiber was a shape other than a substantially triangular shape, the circumscribed circle and the inscribed circle in contact with the outer edge of the fiber cross section were set, and the degree of atypia was obtained from the ratio of these radii. If multiple inscribed circles could be drawn in the fiber cross section, the degree of atypia was determined using the radius of the smallest inscribed circle.

(7) Yarn widening ratio As shown in FIG. 6, fibers (multifilaments) 61 are bundled so that the circumference is 20 cm to form a single ring. The fiber 61 is hung 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 at the lowest point. A load 63, which is 1.52 times the total fineness (dtex) of the fiber, is hung at the lowest point of the ring-shaped fiber 61. The load 63 is hung on the fiber 61 via a joining thread 67 using the fiber used for the measurement. In this state, the fiber width (a) of the multifilament located at the uppermost part of the Teflon (registered trademark) rod 62 and the fiber located 5 cm above the load point (the lowest point of the fiber 61) on the side without the binding point 64. The thickest fiber width (b) is measured, and the ratio (a / b) of the two is calculated. The fibers were changed, the above measurement was repeated 10 times, and the average value was taken 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 a differential pressure of 20 kPa)
A high-pressure air permeability measuring machine (manufactured by OEM System Co., Ltd.) was used at five measurement sites randomly selected from the portions 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 20 kPa differential pressure)
Five 20 cm square test pieces are cut out from any location excluding the range of 30 cm from both ends in the width direction of the fabric, and the test pieces are folded in half along the fiber axial direction (a) and the fiber axial direction (a). ) Is folded in half along the fiber axis direction (b), then half along the fiber axis direction (a), and along the fiber axis direction (b) orthogonal to the fiber axis direction (a). I folded it in half and folded it in 5 cm squares. A load of 50 N was applied to the entire surface of the folded test piece for 1 minute, and then the folded test piece was left unfolded in 20 cm square for 1 minute. A circle with a diameter of 10 cm centered on the intersection of the first and second folds is used as the measurement site, and the air permeability under a differential pressure of 20 kPa is measured using a high-pressure air permeability measuring machine (manufactured by OEM System Co., Ltd.). Was measured. The average value of the five test pieces was taken as the high-pressure air permeability after folding.

(10) Rate of change in air permeability The rate of change in air permeability before and after folding was obtained by the following equation 2.
Ventilation rate change rate (%) = (High-pressure air permeability after folding) / (High-pressure air permeability before folding) x 100 (Equation 2)

(11) Degree of entanglement The degree of entanglement of the raw yarn and the unwound yarn was calculated in accordance with JIS L1013 8.15.

(12) Sliding resistance force Measured by ASTM D 6479.

(13) Amount of protrusion before weaving Using a commercially available stroboscope, the timing at which the reed is completely driven is set to 0 ° = 360 °, and the dial scale mounted on the water jet room loom has a stroboscope. The scale was set to zero. After the warp and weft was inserted, the timing at which the reed came into contact with the protrusion of the weaving front on the nozzle side was read. The measurement was performed 3 times every hour, and the average value for 3 times was recorded.

(14) Number of stops The number of stops for weft driving was measured according to the following equation 7.
Number of stops for weft driving (times / 100m) = {(s ₀ ―s ₁ ) / f ₁ × 100
(Equation 7)
[S ₀ : Total number of stops for weft driving when weaving a certain brand (times), s ₁ : Number of switching of warp and weft raw cheese (times), f ₁ : Overall length of weft weaving for a certain brand (m)]

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

<Example 2>
A fiber having a modified cross section was produced by the same method as in Example 1 except that a nozzle having a variant degree of 4 was used at the time of spinning, and the fiber was woven to obtain a woven fabric. The protrusion angle before weaving was 327 °, the flight of the weft was stable, and the operating rate was 96%. Table 1 shows the physical characteristics of the raw yarn and the physical characteristics of the woven fabric.

<Example 3>
A fiber having a modified cross section was produced by the same method as in Example 1 except that a nozzle having a variant degree of 8 was used at the time of spinning, and the fiber was woven to obtain a woven fabric. The protrusion angle before weaving was 328 °, the flight of the weft was stable, and the operating rate was 97%. Table 1 shows the physical characteristics of the raw yarn and the physical characteristics of the woven fabric.

<Example 4>
A fiber having a modified cross section is manufactured by the same method as in Example 1 except that the warp tension at the time of weaving is 0.39 cN / dtex and the number of threads driven on the machine is 55.5 / 2.54 cm. Then, this was woven to obtain a woven fabric. A plain weave cloth having a woven fabric density of 60 pieces / 2.54 cm was obtained. Table 1 shows the physical characteristics of the raw yarn and the physical characteristics of the woven fabric.

<Example 5>
At the time of spinning, a nozzle having a degree of deformation of 6 was used to obtain 350 dtex, 108 filament triangular cross-section polyamide 66 fibers in the same manner as in Example 1.
The obtained triangular cross-section yarn was used for warp and weft and woven in a crank opening type water jet room. The warp tension was adjusted to 0.39 cN / dtex, the number of warp threads to be driven was set to 61 / 2.54 cm, and the weaving was performed at a loom rotation speed of 600 rpm. At this time, the protrusion angle before weaving was 327 °, the flight of the weft was stable, and the operating rate was 96%. After weaving, the material was passed through a hot water tank at 98 ° C., and the processing tension was adjusted so that the running tension in the warp direction was 0.027 cN / dtex, and the hot water treatment was performed. Subsequently, the drying treatment was performed under a running tension of 0.027 cN / dtex in the warp direction to obtain a plain weave cloth having a warp and weft fabric density of 66 lines / 2.54 cm. Table 1 shows the physical characteristics of the raw yarn and the physical characteristics of the woven fabric.

<Example 6>
A fiber having a modified cross section was produced by the same method as in Example 1, and the fiber was woven in a cam opening type (dwell angle 60 °) water jet room. The warp tension was adjusted to 0.39 cN / dtex, the number of warp threads to be driven was set to 56.5 / 2.54 cm, and the weaving was performed at a loom rotation speed of 600 rpm. At this time, the protrusion angle before weaving was 327 °, the flight of the weft was stable, and the operating rate was 96%. After weaving, the material was passed through a hot water tank at 98 ° C., and the processing tension was adjusted so that the running tension in the warp direction was 0.027 cN / dtex, and the hot water treatment was performed. Subsequently, a drying treatment was performed under a running tension of 0.027 cN / dtex in the warp direction to obtain a plain weave cloth having a warp and weft fabric density of 61 lines / 2.54 cm. Table 1 shows the physical characteristics of the raw yarn and the physical characteristics of the woven fabric.

<Comparative Example 1>
Polyamide 66 resin is melt-extruded using a single-screw extruder, weighed using a gear pump, and extruded to a nozzle (atypical degree 1.0) via a metal non-woven fabric filter (NF-07 manufactured by Nippon Seisen Co., Ltd.). It was a fibrous melt. The fibrous melt is passed through a heating cylinder directly under the nozzle as it is, cooled by cooling air, 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, 470dtex, 144. A polyamide 66 fiber having a round cross section of the filament was obtained.

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

<Comparative Example 2>
A 470 dtex, 144 filament round cross-section polyamide 66 fiber was produced according to the procedure of Comparative Example 1 except that the boiling water shrinkage rate of the polyamide 66 fiber was set to 6.7%, and this was a cam opening type (dwell angle 100 °). Weaved on a rapier loom. After weaving, a plain weave cloth having a weft density of 60 pieces / 2.54 cm was obtained. Table 2 shows the physical characteristics of the raw yarn and the physical characteristics of the woven fabric.
Since weaving was performed on a rapier loom, the loom rotation speed was slow and the productivity of the woven fabric was poor. Moreover, even if weaving at a high density, the high-pressure air permeability was high.

<Comparative Example 3>
According to the procedure of Comparative Example 1, 235 dtex, 36 filament round cross-section polyamide 66 fiber and 235 dtex, 72 filament were produced, respectively, and combined to produce a 470 dtex raw yarn in which two types of single yarn fineness were mixed. This was used for warp and weft and woven in a water jet room with a crank opening. A plain weave cloth having a warp and weft woven density of 54 pieces / 2.54 cm was obtained. Table 2 shows the physical characteristics of the raw yarn and the physical characteristics of the woven fabric.
The woven fabric obtained in Comparative Example 3 had a high high-pressure air permeability as compared with the woven fabric of the example in which the cross-sectional shape of the single yarn fiber was made of fibers having a substantially triangular shape. Further, when an attempt was made to weave at a higher density, the yarn strength was weak due to the mixture of yarns having different single yarn fineness, and the yarn was easily fluffed and could not be woven.

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

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

<Comparative Example 6>
A Y-shaped cross-section polyamide 66 fiber of 470 dtex and 144 filaments was obtained according to the procedure of Comparative Example 1 except that a nozzle having a variant degree of 12 was used at the time of 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 flight of the weft was not very stable, and the number of stops was 103 times / 100 m. Table 2 shows the physical characteristics of the raw yarn and the physical characteristics of the woven 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-shaped cross-section polyamide 66 fiber of 470 dtex and 144 filaments was obtained according to the procedure of Comparative Example 1 except that a nozzle having a degree of deformation of 3 was used at the time of 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 flight of the weft was not very stable, and the number of stops was 103 times / 100 m. Table 2 shows the physical characteristics of the raw yarn and the physical characteristics of the woven 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 woven fabric for an airbag having a higher density and a lower air permeability, and an airbag using the same.

11 Circle inscribed in the discharge hole provided in the nozzle 12 Circle inscribed in the discharge hole provided in the nozzle 13 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 bisected line of a straight line connecting the vertices of the appearing shape 22, 22'Intersection between the vertical bisected line and the outer circumference of the single thread fiber cross section 31, 31'External circle 32, 32'Inscribed circle 33, 33'Triangle connecting the apex of the shape appearing in the cross section of the single thread fiber 34, 34'Circular outer circumference of the single thread fiber 61 Measurement sample (fiber)
62 Teflon® rod with a diameter of 1 cm 63 Load 64 Bundling point 65 Measuring point of the width (a) of the fiber located at the top of the Teflon® rod when a constant tensile tension is applied 66 Constant tensile tension Measurement point of fiber width (b) when

Claims (3)

It is composed of multifilaments having a substantially triangular cross-sectional shape, containing single yarn fibers having a degree of atypia of 1.3 to 2.2, and having an number of entanglements of 10 pieces / m or more and 25 pieces / m or less at the raw yarn stage. A non-coated woven fabric for airbags having a cover factor (CF) of 2050 or more and 2600 or less and an air permeability of 0.25 L / cm2 / min or less under a differential pressure of 20 kPa. It contains single yarn fibers having a substantially triangular cross-sectional shape and a degree of atypia of 1.3 to 2.2.
It is characterized in that after weaving a multifilament having a confounding number of 10 pieces / m or more and 25 pieces / m or less, it is subjected to a hot water treatment through a water tank having a temperature of 50 ° C. or more and 100 ° C. or less.
A method for manufacturing a non-coated woven fabric for an airbag, which has a cover factor (CF) of 2050 or more and 2600 or less, and an air permeability of 0.25 L / cm2 / min or less under a differential pressure of 20 kPa. The method for producing a non-coated woven fabric for an airbag according to claim 2, wherein the woven fabric is not pressure-compressed after being subjected to the hot water treatment.

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