JP2003013336A - Fabric for side air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fabric for a side air bag having excellent mechanical characteristics and heat resistance and low air permeability and excellent housing properties. SOLUTION: This fabric for the side air bag is a fabric of polyamide fibers using a polyamide flat cross-sectional yarn having a single filament cross-sectional shape of 1.5-6 flatness ratio in warp yarns and/or weft yarns. The fabric simultaneously satisfies a specific tensile strength, tear strength, air permeability, housing properties and cover factor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag cloth, and more particularly to an airbag cloth suitable for a side airbag. More specifically, each filament has a flat cross-section, and has excellent mechanical properties, air permeability, and storability, which are obtained by weaving polyamide fibers having specific physical properties of raw yarn as warp and / or weft. The present invention relates to a fabric for a side airbag.

[0002]

2. Description of the Related Art In recent years, airbags have become indispensable as a device for ensuring the safety of passengers in a vehicle, and the rate of attachment to the vehicle is increasing.

The demand for improved reliability of the airbag as a safety device is further increasing, but other required characteristics for the airbag are further compactness and scratches on the occupant's face when the airbag is deployed at the time of a collision. For example, prevention and cost reduction are required. For this reason, further improvement in quality is required for the airbag fabric and the airbag raw yarn constituting the airbag in order to satisfy the above required performance.

Many techniques have been proposed so far for realizing an airbag that is excellent in foldability and has a small storage volume without deteriorating the mechanical characteristics of the airbag. Among them, flat yarn is used. The technique of using a fabric as an airbag base fabric has received attention from the industry because it satisfies the performance required for a next-generation airbag such as safety and compactness.

Prior arts relating to an airbag using such a flat yarn are disclosed in JP-A-4-193647, JP-A-4-201650 and JP-A-7-252.
740, JP-A-8-60425, US Pat. No. 6,370,47, and the like.

That is, Japanese Patent Laid-Open No. 4-193647 and Japanese Patent Laid-Open No. 4-201650 have a single yarn fineness as a fabric for airbags which is lightweight, excellent in flexibility and storability, and excellent in mechanical properties. 1.0-12 denier,
Disclosed is an airbag fabric using a polyamide multifilament composed of a plurality of single yarns having a modified cross section including a flat yarn having a single yarn deformation degree of 1.5 to 7.0.
However, this technology discloses that when applied as a coating base fabric coated with an elastomer such as silicone rubber, a lightweight base fabric for airbags having excellent flexibility and storability can be obtained. No mention is made of application to the base fabric, and although it is disclosed in the examples that the fabric before silicone rubber application is soft and excellent in foldability, it is important to note that it is unique to non-coated fabric. It does not refer to the required gas permeability and the time-dependent change in gas permeability.

Japanese Unexamined Patent Publication No. 7-252740 discloses a total fineness of 180 D or more and 450 D or less, and a single yarn fineness of 0.1 d or more 7.
A multifilament yarn having a strength of 0 d or less, a strength of 7.5 g / d or more, and an elongation of 12.0% or more is used, and the air flow rate under a pressure of 1.27 cm is 1.2 cm ³ / sec / cm ² or less. It discloses a base fabric for an airbag. Certainly, by using the flat yarn and the raw yarn having the specific total fineness and single yarn fineness, it is possible to obtain the air bag base fabric having low breathability, light weight and excellent storability.
However, the technology has a total fineness of 180D or more and 45
It is a technique using a polyester flat yarn having a relatively fineness of 0 D or less, and the airbag obtained here does not sufficiently satisfy the strength, toughness and heat resistance required for a side airbag.

Further, Japanese Patent Application Laid-Open No. 8-60425 has one to three symmetrically-provided convex portions consisting of substantially semicircular projections in the longitudinal direction of a flat base in a cross section of a single yarn,
Disclosed is a fiber for an airbag in which the ratio of the long axis to the short axis of the flat yarn is 4/1 to 2/1, the single yarn fineness is 2 to 10d, and the strength is 7 g / d or more. is there. The fabric using the flat cross-section yarns having such protrusions is characterized by being excellent in flexibility and compactness, and particularly capable of producing yarns with good yarn-forming property and high strength. However, this technique does not refer to the strength, toughness, and heat resistance of the fabric that should be provided as a fabric for a side airbag, and in fact, the technique describes polyethylene terephthalate fiber and polytetramethylene adipamide fiber. Therefore, it can be said that the obtained fabric does not simultaneously satisfy the strength, toughness, heat resistance and the like. In particular, it cannot be said that both materials mentioned above have sufficient toughness. Further, although having a protrusion is advantageous in terms of yarn formability, it is disadvantageous in terms of compactness and breathability of the fabric.
It is necessary to select a flat yarn having an advantageous shape as a fabric characteristic, and to solve the spinnability by another spinning means.

Further, in US Pat. No. 6,370,047, it is effective to use a diamond-shaped or S-shaped flat cross-section yarn as a raw yarn of a polyester fiber cloth excellent in covering property and flexibility. It is disclosed that the polyester fiber cloth is also useful as a cloth for airbags. However, the polyester fiber cloth using the diamond-shaped or S-shaped flat cross-section yarn described in the art is surely excellent in covering property and flexibility as a cloth made of polyester fiber. When compared with a conventional fabric made of fibers, it could not be said to have a remarkable effect.

Storability, which is one of the performances conventionally required for a fabric for a side airbag, is that since it is required to have high strength, it has excellent foldability even though it is a high-density fabric. The low air permeability, which is another important required performance, is achieved by using a raw yarn that is less likely to cause an intersection shift between the warp and the weft and has excellent covering properties between filaments in the yarn. In technology,
It has been difficult to satisfy both the storage property and the air permeability at the same time.

That is, in combination with the high strength performance particularly required for the side airbag fabric, a side airbag fabric that simultaneously satisfies low air permeability and excellent storability / compactness has not been proposed, and There is a great need for its realization, but at present it is.

[0012]

In view of the background of the prior art, the present invention provides a fabric for a side airbag having excellent mechanical properties, breathability and storability, especially as a non-coated fabric at a low cost. It is something to do.

[0013]

The present invention employs the following means in order to solve the above problems. That is, the side airbag fabric of the present invention has a flatness ratio of 1.5, which is represented by the ratio a / b of the major axis length a and the minor axis length b.
A polyamide flat cross section yarn having a single yarn cross section shape of
A polyamide fiber cloth used for at least one of warp threads and warp threads, and characterized in that the cloth satisfies all of the following four characteristics. (1) The tensile strength measured according to JIS L1096 (6.12.1A method) is 700 to 1000 N / cm. (2) The tear strength measured according to JIS L1096 (6.15.2A-2 method) is 250 to 500N. (3) Using a laminar flow pipe type air permeability tester, the diameter of the fabric is 10
The air permeability of the base cloth, which is represented by the flow rate of the air passing through when the air adjusted to a pressure of 19.6 KPa is applied to the cm part,
It is 1 to 40 cc / cm ² / sec. (4) Total fineness of warp is D1 (dtex), weaving density is N1
(Book / 2.54 cm), the total fineness of the weft is D2 (dte
x), when the weave density is N2 (books / 2.54 cm), (D1 × 0.9) ^1/2 × N1 + (D2 × 0.9)
Cover factor represented by ^1/2 × N2 is 1700 to
2200.

Further, in the fabric for a side air bag of the present invention, an air bag having a capacity of 60 L is 150 × 150.
First, fold it into a bellows from the left and right 4 times each, and then fold it into a bellows 4 times from the top and bottom, and when the load of 10 N is applied to the folded bag, the storability under load is 35. ˜55 mm, the storability during load unwinding indicated by the thickness of the bag when unwinding a 10 N load is 40 to 60 mm, the flat cross section yarn has the following fiber characteristics (a) to (e): Simultaneously satisfying (a)
The total fineness determined by JIS L-1013 is 550-8
00dtex, (b) single yarn fineness determined by JIS L-1013 is 3 to 7 dtex, (c) JIS L-10
According to No. 13, the strength measured under the conditions of a trial length of 25 cm and a tensile speed of 30 cm / min is 7 to 9 cN / dtex, and (d) JI.
According to SL-1013, test length 25 cm, pulling speed 30
Elongation measured under conditions of cm / min is 15 to 30%, (e)
Raw yarn is sampled in the shape of a hank, 20 ° C, 65% RH
1cN / for samples adjusted for 24 hours or more in the temperature and humidity control room
A load equivalent to dex was applied to measure the length L ₀ , and then the sample was immersed in boiling water for 30 minutes without tension, and then air-dried in the greenhouse control chamber for 4 hours, and 1 cN / d was again applied to the sample.
The length L ₁ is measured by applying a load equivalent to ex, and from the respective lengths L ₀ and L ₁ , the formula [(L ₀ −L ₁ ) /
The shrinkage factor after boiling water treatment calculated as L ₀ ] × 100 is 4
-10% and non-coated cloth are all preferable conditions, and by adopting those satisfying these conditions, it is possible to provide a cloth for a side airbag that exhibits more excellent effects.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has been earnestly studied on the above problems, that is, a fabric for a side airbag having excellent mechanical properties, breathability and storability, and is constructed by using a specific polyamide flat cross section yarn. When a side airbag is made by selecting and using a fabric for an airbag that has a fabric strength, air permeability, cover factor and storability within a specific range, It is a solution to solve all at once.

That is, the fabric for a side air bag of the present invention is a fabric used for at least one of warp yarns and weft yarns having a single yarn cross-sectional shape with an oblateness of 1.5 to 6, and It is an important requirement that the fabric characteristics (1) to (4), preferably (1) to (6), are all satisfied. (1) Tensile strength: 700 to 1000 N / cm, (2) Tear strength: 250 to 500 N, (3) Air permeability: 1 to 40 cc / cm ² / sec, (4) Cover factor: 1700 to 2200, (5) Storability under load: 35-55 mm, (6) Storability under load release: 40-60 mm.

Further, the side airbag fabric of the present invention can sufficiently exhibit the effects of the present invention when used as a non-coated fabric without being coated with an elastomer or the like.

The strength of the fabric for side air bubbling of the present invention has a tensile strength of 700 to 1000 N / cm, preferably 650 to 950 N / cm, and a tear strength of 250 to 500.
N, preferably 300-450N. The range of these two strengths is not limited to the pressure directly applied to the cloth due to the pressure at the time of the gas explosion at the time of the actual side airbag collision, as well as the friction between the cloth and the storage device and the friction between the cloths. It is represented as a characteristic representative of mechanical performance. That is, it means that if the cloth satisfies the above tensile strength and tear strength, it normally satisfies the burst strength and the friction strength. When the tensile strength is less than the above range and the tear strength is less than the above range, the performance as the fabric for the side airbag is not satisfied,
On the other hand, if each of these strengths exceeds the above range,
It is excessive performance, and it is recommended that efforts should be made to reduce costs within the range of required performance.

Regarding the air permeability of the fabric for a side airbag of the present invention, it is required that the air permeability under a high pressure is low in order to enhance safety, and the air permeability under a pressure of 19.6 KPa is 1 to 1. 40 cc / cm ² / sec, preferably 5
It is necessary to satisfy the range of ˜35 cc / cm ² / sec.

When the air permeability exceeds the above range, the bag deployment speed becomes slower and a normal deployment shape cannot be obtained during the bag deployment process, which is unfavorable for ensuring the safety of passengers.

The side air bag fabric of the present invention preferably has a storage capacity under load of 35 to 55 mm, more preferably 30 to 50 mm, and a storage capacity under load release of 40 to 6 as well.
The range is 0 mm, preferably 35 to 55 mm.

Here, the measurement of the storability under load and the storability under load unwinding is carried out by the following method in detail according to FIGS. 4 and 5.

Two pieces of circular cloth having a diameter of 725 mm are cut from the cloth for an air bag by a punching method, and three circular reinforcing cloths of the same cloth having a diameter of 200 mm are laminated at the center of one circular cloth. , Diameter 110mm, 145mm, 17
470 of nylon 6.6 fiber for both upper and lower threads on the 5 mm line
A sewing thread composed of dtex / 1 × 3 is sewn by a lock stitch and a hole having a diameter of 90 mm is provided to serve as an inflator attachment port. Further, one circular reinforcing cloth made of the same base cloth and having a diameter of 75 mm is oppositely applied at a position of 255 mm in the bias direction from the center, and the diameter is 50 m.
A sewing thread composed of 470 dtex / 1 × 3 of nylon 6.6 fiber for both upper and lower threads is sewn on the sewing machine by lock stitch, and two vent holes with a diameter of 40 mm are provided on the line of m and 60 mm.

Next, the reinforcing cloth side of the circular cloth is placed outside, and the circular cloth is overlapped with the circular cloth by shifting the meridian axis by 45 degrees, and the upper and lower threads are made of nylon 6 on both the circumferences of diameters of 700 mm and 710 mm. A sewing thread composed of 1400 dtex / 1 of 6 fibers is sewn by a double chain stitch, and then the bag body is turned upside down to produce an airbag of 60 L capacity.

Next, as shown in FIG. 4, this airbag I is first folded from the left and right sides to the bellows 4 times in the direction II so as to have a size of 150 × 150 mm, and then from the upper and lower sides II.
Fold it into a bellows 4 times in the direction I, and this folded bag IV
Then, as shown in FIG. 5, a load V of 10 N is applied, and the thickness VII of the bag at that time is measured. Then, the thickness VIII of the bag after removing the load IV is measured.

Then, the above-mentioned VII is made to be storable under load, and VI
II is the storability when the load is unwound.

If the storability under load and the storability during load release exceed the above-mentioned ranges, the storability is inferior to the conventional ones, so that it cannot be used in a vehicle model such as a small car or the like in which compactness is particularly important. Further, if the storability under load and the storability during unloading are smaller than the above ranges, the storability is more satisfactory than before, but the tensile strength and tear strength are inferior and the air permeability tends to decrease, which is not preferable.

The side airbag fabric of the present invention is produced by controlling the weaving of the polyamide fiber having a fine single yarn fineness having a flat cross section so as to have a cover factor in a specific range, whereby the above effect, In particular, in order to secure heat resistance with high tenacity and high toughness, it was possible to improve the storability while using a yarn having a relatively high total fineness. The flatness of the cross-sectional shape of the single yarn is 1.5
It is important that it is -6, preferably 2-5.

The flatness referred to here is a value calculated by obtaining the major axis length a and the minor axis length b of the single yarn and calculating the ratio a / b thereof, as shown in FIGS.

The cross-sectional shape of the polyamide fiber having a flat cross section is usually an ellipse as shown in FIG. 2, but the flatness is 1.5 to 6
Any shape other than the elliptical shape may be used as long as it satisfies the range. For example, a left-right symmetrical type such as a rectangle, a rhombus, and a cocoon type as shown in FIG. 1 may be a left-right asymmetric type, or a combination of these types. Further, with the above as a basic type, a projection, a depression, or a part There may be a hollow portion.

When the flatness is less than the above range, the effect of using the flat cross section yarn cannot be sufficiently obtained. On the other hand, when the flatness exceeds the above range, the physical property required for the airbag yarn according to the present invention, that is, the strength. Is 7-9 cN / dtex, and the elongation is 15-
It is difficult to obtain a yarn having a shrinkage rate of 30% and boiling water shrinkage rate of 4 to 10%, and the performance of the fabric for a side airbag, which is the object of the present invention, may not be satisfied. Also,
Even if the above-mentioned raw yarn physical properties and fabric properties are obtained, it is difficult to obtain a good raw yarn quality, so that the process passability in the weaving process is poor and it is not suitable for industrial production.

The polyamide flat cross section yarn used in the fabric for a side air bag of the present invention preferably has the following physical properties. (A) Total fineness: 550 to 800 dtex, (b) Single yarn fineness: 3 to 7 dtex, (c) Strength: 7 to 9 cN / dtex, (d) Elongation: 15 to 30%, (e) Boiling water shrinkage : 4 to 10%.

That is, the side airbag is deployed from the left and right sides of the occupant's seat at the time of collision, and for the purpose of instantaneously protecting the side surface of the occupant, high-temperature and high-pressure gas collides with the bag cloth. Requires high strength, toughness, and heat resistance. Therefore, it is necessary to use a yarn having high strength, toughness, heat resistance and the like for the fabric for the side airbag.

The material for the side airbag fabric of the present invention is a polyamide fiber, and polyhexamethylene adipamide, polycapramide, polytetramethylene adipamide and copolymers and blends of these polymers are used. A particularly preferable polymer is polyhexamethylene adipamide (nylon 66), and a sulfuric acid relative viscosity is preferably 3. in order to obtain a fiber having high strength and high toughness.
It is preferable to use a high molecular weight polyamide of 0 or more, more preferably 3.5 or more.

Next, a method for producing a polyamide flat cross section yarn suitable as a fabric for a side airbag of the present invention will be described.
An example thereof will be described with reference to the schematic diagram of the process in FIG.

The polyamide flat cross section yarn is produced by using a polyamide polymer, preferably by melt spinning and drawing.

First, the polymer is heated and melted by a spinning machine,
Spinned from the spinneret.

Here, in order to obtain a polyamide fiber multifilament composed of a single yarn having a flat cross section, the shape of the single discharge hole of the spinneret should be a flat shape so that a desired flat cross section yarn can be obtained. is important. Particularly, the shape is designed in consideration of the change due to the surface tension of the molten polymer until it is spun and cooled and solidified.

Yarn (4) spun from the spinneret pack
Is preferably a cooling unit (2) with a cooling air of 20 to 50 m / min, and a spinning duct having a length of 1 to 5 m after being slowly cooled by passing through a heating cylinder (not shown) installed immediately below the spinneret surface. (3)
It is cooled and solidified through, and then an oil agent is applied in the oil supply device (1).

Next, the yarn (4) is taken up by the take-up rollers (5) and (6) at a predetermined speed, and then heat-drawn by the heat-drawing roller groups (7), (8) and (9). To be done. The stretched yarn (4) was loosened between the second stretching roller (9) and the tension adjusting roller (10) and then installed between the tension adjusting roller (10) and the winder (13). After passing through the yarn path regulation guides (12, 12 '), entanglement is given by the entanglement giving device (11), and then wound by a winder (13). The confounding device (11) is the second
It can also be installed between the stretching roller (9) and the tension adjusting roller (10).

The polyamide fine cross-section yarn thus obtained has a total fineness of 550 to 800 dtex, preferably 5
It is 50 to 700 dtex. When using ordinary high-strength polyamide fiber, it is necessary to set the cover factor to a certain value or more in order to achieve sufficient fabric strength as a side airbag. Therefore, it is necessary for the raw yarn to have a total fineness of a certain value or more, that is, 550 dtex or more. When it is less than 550, it is difficult to achieve the performance of the fabric for a side airbag of the present invention, however high the weaving density is. On the other hand, when the total fineness exceeds the above range, although the fabric strength is satisfied, the side air bag fabric of the present invention cannot satisfy the storability which is an important performance.

Next, the single yarn fineness of the polyamide flat cross section yarn is preferably 3 to 7 dtex, more preferably 4 to 7 dtex.
It is dtex. The smaller the single yarn fineness is, the softer the resulting fabric is, the better the storability is, the lower the air permeability is, and the less the air permeability is changed with time. That is, when the single yarn fineness is reduced, the number of single yarns is increased, the covering property is improved, and the number of intersections between the warp yarns and the weft yarns is increased, so that the displacement of the intersections is less likely to occur.

That is, when the flat cross section yarn is used, the effect of less than 3 dtex obtained when the conventional circular cross section yarn is used can be achieved as 3 dtex or more. This is easy for yarn production, and is extremely advantageous in securing the yarn production yield and the quality of the raw yarn. Further, if the single yarn fineness exceeds the above range, the side airbag fabric of the present invention is not preferable because a large effect cannot be obtained in the storability characteristic of the fabric for a side airbag as compared with the storability achieved by the conventional technique. .

Polyamide flat cross section yarn strength is 7-9cN
/ Dtex, preferably 7.5 to 9 cN / dtex, and the elongation in the range of 15 to 30%, preferably 12 to 28%, to obtain the side airbag fabric targeted by the present invention. it can. That is, when the flatness of the polyamide flat cross section yarn is within the above range, strength and elongation comparable to those of the conventional polyamide fiber having a circular cross section can be obtained. If the strength is less than the above range, the fabric strength of the present invention may not be obtained, and if the strength exceeds the above range, higher fabric strength may be obtained.
This is not preferable because the yarn yield of the raw yarn is lowered and defects such as a large amount of raw yarn fluff occur.

The elongation indicates the range in which the fabric performance of the present invention is satisfied and the strength of the raw yarn is obtained while satisfying the yarn production yield and the raw yarn fluff.

Further, the boiling water shrinkage ratio of the polyamide flat cross section yarn is preferably 4 to 10%, more preferably 5 to 8%, which is the boiling water shrinkage ratio of a normal yarn for airbag. At the same level as. Thus, although it is a flat yarn, it shows that it can be processed under the same weaving, scouring, and heat setting processing conditions as the conventional circular cross-section yarn, that is, it can be produced without significantly changing the conventional fabric manufacturing process and conditions. .

The side airbag fabric of the present invention obtained by weaving the above polyamide flat cross section yarn has a cover factor of 1700 to 2200, preferably 1800 to 21.
It is a fabric woven so that it becomes 00.

The term "cover factor" as used herein means that of warp yarns.
Total fineness is D₁(Dtex), weaving density is N₁(Book / 2.5
4 cm), the total fineness of the weft is D₂(Dtex), weave density
N₂When (book / 2.54 cm), the formula (D₁×
0.9)¹/²× N₁+ (D ₂× 0.9)¹/²× N₂
It is a value represented by.

When the cover factor is less than the above range,
When used as a non-coated airbag, there is a problem that the air permeability is high and the deployment speed of the airbag is slow, so that safety cannot be ensured. In addition, since the cross point shift between the warp and the weft is likely to occur, the air permeability may change over time, which is not preferable. On the other hand, when the cover factor exceeds the above range, the woven density becomes high, and the cloth becomes paper-like, and the storability and compactness deteriorate.
In addition, the amount of fibers used increases and the weaving cost also increases, which is not preferable.

As described above, the cover factor is greatly related to the breathability and storability of the cloth, and it is very important for the side air bag cloth to be in the appropriate range. The fabric for a side airbag of the present invention uses polyamide flat cross-section yarns and therefore has extremely excellent covering properties, and has a low air permeability even when the cover factor is 10 to 30% lower than that of a fabric using ordinary circular cross-section yarns. The feature is that

The fabric for side airbag of the present invention is obtained by warping and weaving the above-mentioned polyamide flat cross section yarn. The cloth obtained after weaving may be calendered or the like in some cases, but in the present invention, it can be used as a cloth for a side airbag only by scouring treatment or heat setting.

In the fabric for a side air bag of the present invention, it is particularly important to design and weave the fabric within the range of the specified cover factor. As the loom, a water jet loom is often used, but a rapier room or an air jet loom can also be used.

In this way, the raw yarn having the above-mentioned raw yarn characteristics and the cloth for a side airbag of the present invention having the cloth characteristics can be obtained.

[0054]

EXAMPLES The present invention will be specifically described with reference to the following examples.

The definitions and measuring methods of the physical properties used in the text of the specification and the examples are as follows. [Flatness]: A cross section of the fiber was photographed at a magnification of 200, and the lengths of the major axis length a and the minor axis length b of the single yarn were measured on the photograph.
The flatness was defined as / b. Ten single yarns were measured and shown as an average value. [Fineness]: The true amount fineness determined by JIS L-1013 was determined. [Strength, elongation]: Test length 2 according to JIS L-1013
It was measured under the conditions of 5 cm and a pulling speed of 30 cm / min. [Boiling water shrinkage]: Sampling the raw yarn into
The sample was adjusted in a temperature / humidity control room at 20 ° C. and 65% RH for 24 hours or more, and a load corresponding to 1 cN / dex was applied to the sample to give a length L _0.
To measure. Next, this sample is immersed in boiling water for 30 minutes in a tension-free state, air-dried for 4 hours in the greenhouse regulation chamber, and a load equivalent to 1 cN / dex is applied to the sample again to measure the length L ₁ . The shrinkage rate of boiling water was calculated from the respective lengths L ₀ and L ₁ by the following formula. Boiling water shrinkage =
[(L ₀ −L ₁ ) / L ₀ ] × 100 (%) [Tensile strength of cloth]: JIS L1096 (6.12.
1A method). [Tear strength of cloth]: JIS L1096 (6.15.
2A-2 method), and an average value in the warp direction and the weft direction was obtained. [Aeration amount]: Using a laminar flow tube type air permeability tester in a circular portion having a diameter of 10 cm, the fluid (air) is adjusted to a pressure of 19.6 KPa and allowed to flow, and the air flow rate (cc / cm) passing therethrough
² / sec) was measured. [Storability under load, storability during load release]: First, after folding an airbag having a capacity of 60 L into bellows 4 times from the left and right so as to have a size of 150 × 150 mm, as shown in FIG.
The bag was folded into a bellows four times from the top and bottom, and a load of 10 N was applied to the folded bag as shown in FIG. 5, and the thickness of the bag at that time (storability under load) was measured. After that, the thickness of the bag after removing the load (storability upon unloading) was measured.

[Examples 1 to 6 and Comparative Examples 1 to 7] 96% measured at 25 ° C. using an extruder type spinning machine, containing a copper salt and an alkali metal halide as antioxidants.
Nylon 66 chips with sulfuric acid relative viscosity 3.7 of 295 ℃
Melt-spun. As the spinneret, spinnerets having different shape, size and number of holes of the spinneret were used, and yarns having different total fineness, single yarn fineness and single yarn cross-sectional shape as shown in Table 1 were spun.

A heating cylinder heated to 250 ° C. was provided immediately below the spinneret, and a slow cooling spinning was carried out by covering 25 cm from the spinneret surface with a heating atmosphere. The yarn passing through the heating cylinder was cooled and solidified by cold air, and then a non-aqueous oil agent was applied and wound around a take-up roll and taken out. The taken-up yarn was continuously sent to the hot drawing zone and directly spun and drawn.

First, 5 is set between the take-up roller and the yarn feeding roller.
% Stretch, then the first stage stretching between the yarn feeding roller and the first stretching roller, and the second stage stretching between the second stretching roller and the tension adjusting roller. Relaxing heat treatment was performed between them, and it was wound by a winder. The temperature of each roller was set to room temperature for the take-up roller, 40 ° C. for the yarn feeding roller, 130 ° C. for the first drawing roller, and 140 ° C. for the tension adjusting roller. The second stretching roller was appropriately changed at 220 to 240 ° C. For the spinning speed, the speed of the second drawing roller is set to 360
The strength of the original yarn is about 8.0c by changing the draw ratio for each yarn having different cross-sectional shape of single yarn and fineness of single yarn.
The yarn was made so as to have N / dtex.

The characteristics of the obtained yarn are shown in Table 1.

Next, the yarn for airbag and the yarn for comparison obtained by the respective methods were each warped at a speed of 200 m / min, and then woven in a water jet loom (ZW303) manufactured by Tsudakoma. Weaving was performed at a rotation speed of 800 rpm while changing the density. As a result, raw fabrics having different cover factors were obtained, and then the raw fabrics were directly dried at 110 ° C. and then heat set at 180 ° C. to obtain a fabric for a side airbag. The cloth design conditions and the cloth characteristics are shown in Tables 1 and 2.

[0061]

[Table 1]

[0062]

[Table 2]

As is clear from the results shown in Table 1, Example 1
The side airbag fabrics Nos. 6 to 6 have excellent mechanical properties, low air permeability, and excellent storability and compactness as compared with the side airbag fabrics of Comparative Examples 1 to 7 It turns out to be optimal.

[0064]

EFFECTS OF THE INVENTION According to the present invention, a fabric for a side airbag having excellent mechanical properties and heat resistance, low air permeability and storability, that is, excellent compactness can be manufactured without coating, and the cost can be reduced. Can be provided extremely advantageously and stably.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a polyamide flat cross-section yarn used in the present invention.

FIG. 2 is a cross-sectional view showing another example of the polyamide flat cross-section yarn used in the present invention.

FIG. 3 is an explanatory view showing an example of an apparatus for producing a polyamide flat cross section yarn used in the present invention.

FIG. 4 is an explanatory diagram showing a folding method of an airbag in a storability test.

FIG. 5 is an explanatory diagram showing a method of applying a load after folding the airbag in the storability test.

[Explanation of symbols]

1 lubricator 2 Cooling unit 3 spinning ducts 4 threads 5 take-up roller 6 take-up roller 7 yarn feeding roller 8 First stretching roller 9 Second stretching roller 10 Tension adjusting roller 11 Confounding device 12 Thread guide guide 13 Winder a Long axis length b Minor axis length

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Claims (4)

[Claims] 1. A polyamide flat cross section yarn having a monofilament cross section having an oblateness of 1.5 to 6 represented by the ratio a / b of the major axis length a and the minor axis length b is at least one of a warp and a warp. A fabric for a side airbag, which is a polyamide fiber fabric used in, and which satisfies all of the following four characteristics. (1) The tensile strength measured according to JIS L1096 (6.12.1A method) is 700 to 1000 N / cm. (2) The tear strength measured according to JIS L1096 (6.15.2A-2 method) is 250 to 500N. (3) Using a laminar flow pipe type air permeability tester, the diameter of the fabric is 10
The air permeability of the base cloth, which is represented by the flow rate of the air passing through when the air adjusted to a pressure of 19.6 KPa is applied to the cm part,
It is 1 to 40 cc / cm ² / sec. (4) Total fineness of warp is D1 (dtex), weaving density is N1
(Book / 2.54 cm), the total fineness of the weft is D2 (dte
x), when the weave density is N2 (books / 2.54 cm), (D1 × 0.9) ^1/2 × N1 + (D2 × 0.9)
Cover factor represented by ^1/2 × N2 is 1700 to
2200. 2. The fabric comprises an airbag having a capacity of 60 L.
First, fold it into a bellows 4 times from the left and right so that it is 50 x 150 mm, then fold it into a bellows 4 times from the top and bottom, and store it under the load indicated by the bag thickness when a load of 10 N is applied to this folded bag. Sex is 35-55mm
2. The cloth for a side airbag according to claim 1, wherein the bag has a storability during load unrolling, which is represented by the thickness of the bag when unloaded with a load of 10 N, of 40 to 60 mm. 3. The flat cross section yarn has the following (a) to (e):
A contract that is characterized by satisfying all the fiber characteristics of
The fabric for a side airbag according to claim 1 or 2. (A) The total fineness determined by JIS L-1013 is 55.
It is 0 to 800 dtex. (B) The single yarn fineness determined by JIS L-1013 is
It is 3 to 7 dtex. (C) According to JIS L-1013, test length 25 cm, pull
The strength measured under the tension speed of 30 cm / min is 7 to 9c.
N / dtex. (D) According to JIS L-1013, test length 25 cm, pull
The elongation measured under the tension rate of 30 cm / min is 15 to 3
It is 0%. (E) The raw yarn is sampled in the shape of a cassette, and the temperature is 20 ° C.
For samples that have been adjusted for 24 hours or more in the% RH temperature and humidity control room,
Length L with a load equivalent to 1 cN / dex₀Measure
Then, soak the sample in boiling water for 30 minutes without tension.
After soaking, air-dry in the greenhouse control room for 4 hours, then re-sample
Apply a load equivalent to 1 cN / dex to the length L₁Measure
And each length L₀And L₁From the expression [(L₀
-L₁) / L ₀] After boiling water treatment calculated as × 100
The shrinkage rate is 4 to 10%. 4. The side airbag fabric according to claim 1, wherein the fabric is a non-coated fabric.