JP2002225660A - Air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air bag, lighter, well compact, superior in folded storage property, hard to break through during roll-over of a body and less liable to damage to an occupant due to frictional scratch. SOLUTION: The air bag comprises at least two base clothes using fabrics formed of polyamide fibers with a cover factor of 1800 or more, the base cloth on a window side having higher bursting strength than the base cloth on an occupant side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag installed for the safety of a vehicle occupant.

[0002]

2. Description of the Related Art Airbags are increasingly used as safety devices for protecting occupants of automobiles, and airbags for driver and passenger seats are almost standard equipment. Attachment of side bags to seats and curtain airbags to windows to protect parts is being studied.

[0003] The side bag and the curtain airbag are designed to secure the internal pressure of the bag for 4 to 5 seconds for the purpose of protecting the occupant in the event of a side collision of the vehicle and in the event of a rollover. Its function is different from that of a conventional driver's seat bag or a passenger's seat bag that inflates and deflates the bag within one second. In order to maintain the internal pressure of the airbag for a long time, it is necessary to use a base cloth that is not easily broken even when it hits glass or crushed stone. Are used. For this reason, since the thickness of the base fabric is large, it is necessary to take a large volume at the time of storage, which is a problem when emphasizing the space in the vehicle.

[0004]

DISCLOSURE OF THE INVENTION The present invention relates to air that is lightweight, excellent in compactness, excellent in folding storage, hard to break through when a vehicle rolls over, and less injured by occupants due to frictional abrasion. It is an object to provide a bag, in particular a side airbag and a curtain airbag.

[0005]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have accomplished the present invention. That is, the present invention is as follows. 1. An air characterized by being composed of two or more base fabrics made of a polyamide fiber and using a woven fabric having a cover factor of 1800 or more, wherein the window-side base fabric has a higher bursting strength than the occupant-side base fabric. bag.

[0006] 2. The average bending stiffness (B) of the occupant-side base fabric measured by KES is 0.5 to 8 m in both the warp and weft directions.
^{2. The} airbag according to the above item 1, wherein the airbag is N · cm ² / cm. 3. 3. The airbag according to the above 1 or 2, wherein the surfaces on the side coated with the resin are sewn together with a resin-coated cloth.

[0007] The burst strength is JIS L-1096.
(Burst strength B method). Hereinafter, the present invention will be described in detail. In the present invention, the woven density of the base fabric is 1800 or more, preferably 1800 to 2500, in terms of the cover factor (CF) of the woven fabric. When the cover factor is less than 1800, the tensile mechanical properties of the base fabric are low, and the mechanical properties at the time of operating the airbag may not be satisfied. If it exceeds 2500, weaving tends to be difficult.

[0008] The cover factor referred to here is the square root of the fineness of the yarn constituting the woven fabric and the weaving density (2.54 cm).
The sum of the product of the product and the number of threads per hit) in the warp and weft directions. That is, it is a value calculated by the following equation. K = (D ₁ ) ^1/2 × N ₁ + (D ₂ ) ^1/2 × N _{2 In the} formula, K is the cover factor, and D ₁ is the fineness of the warp (dt)
ex), N ₁ is woven of warp density (the /2.54Cm),D ₂
The fineness of the weft (dtex), N ₂ is woven of weft density (the /
2.54 cm).

[0009] The bursting strength of the base fabric is greatly affected by the fineness of the fibers used in the base fabric and the cover factor.
The base cloth on the window side is required not to be broken not only when the vehicle rolls over but also when it hits crushed stone. For that purpose, it is necessary to increase the burst strength of the base fabric, and the burst strength is preferably 1500 N or more, more preferably 2000 to 4000 N, as measured by JIS L-1096 (burst strength B method). In addition, the crew
If it does not burst when the airbag is deployed, it may be lower than the window side, and the difference in bursting strength between the window side and the occupant side base cloth is 100 to 100%.
There may be about 2000N.

In order to increase the bursting strength of the base fabric, a fiber having a large fineness is preferable, and in order to reduce the compactness of the folded base fabric and the surface roughness of the base fabric, the fineness is small. Things are good. The fineness is preferably 235 to 500 dtex to ensure high burst strength, and 50 to 250 dtex for compactness and reduced friction and abrasion. As the side airbag and curtain airbag base fabric satisfying both high burst strength and compactness, it is preferable that the base fabric on the window side has a large fineness and the base fabric on the occupant side has a small fineness. The difference in fineness on the side is preferably 50 to 400 dtex.

The fineness of the warp (or weft) refers to the total fineness of the yarns constituting the unit of the weaving structure in the warp direction (or the weft direction) of the base fabric. When it is a book yarn, it refers to its fineness, and when it is a plurality of ply-twisted or aligned yarns, it refers to the total fineness of each yarn. The single fiber fineness of the fiber is 0.5% in view of the compactness of the base fabric.
~ 4.5 dtex is preferred. Within this range, the base fabric is soft, and there is no occurrence of single yarn breakage (fuzz) in the spinning process.

The tensile strength of the fiber is preferably at least 5.7 cN / dtex, more preferably 6.2 to 9.7 cN / d.
tex. When the tensile strength is in this range, it is possible to satisfy the pressure resistance required at the time of deployment of the airbag, there is no breakage of single yarn of the fiber at the time of yarn production, and there is an increase in the number of stops in weaving and It is an excellent grade product without any weaving defects.

As for the compactness of the base fabric, the lower the average bending stiffness (B) in the warp and weft directions, the better the foldability. Further, after the airbag is deployed, the occupant's face and head during rollover of the vehicle body In order to reduce frictional abrasion of the portion, it is preferable that the occupant side airbag has a small surface roughness of the base cloth. As described above, in order to improve the compactness of the airbag and to reduce frictional rubbing, the occupant-side fabric has a mean bending stiffness (B) per unit width in the meridian and weft directions of 0 in the KES measurement. 0.5-8.0 mN · cm ²
/ Cm, more preferably 5.0 m
N · cm ² / cm or less.

Further, the surface roughness (SMD) of the base fabric in the warp and weft directions is preferably 1 to 10 μm, more preferably 8 μm or less. In the present invention, the fiber used is preferably a synthetic fiber, and may be a polyester fiber or a polyamide fiber. More preferably, the fiber is a polyamide fiber having a large heat capacity at the time of temperature rise, and has a melting point of 2%.
Fibers mainly composed of polyhexamethylene adipamide (hereinafter simply referred to as nylon 66) having a temperature of 15 ° C. or higher are particularly preferred.

As the nylon 66 fiber, nylon 6 is used.
6 homopolymer fiber, nylon 66 copolymer (nylon 66/6, nylon 66 / 6I, nylon 66/61
0) and fibers blended with a nylon-based polymer (nylon 66, nylon 6, nylon 610, etc.) are preferred from the viewpoint of heat resistance. The fiber may contain various additives that are commonly used to improve productivity or properties in the production and processing steps of the polymer and the yarn.
For example, a heat stabilizer, an antioxidant, a light stabilizer, a leveling agent, an antistatic agent, a plasticizer, a thickener, a pigment, a flame retardant, a matting agent and the like can be contained.

In particular, since the base fabric for an airbag is required to have heat resistance of mechanical properties, it is desirable that the polyamide fiber contains a copper compound, and the kind and amount of addition are effective. Should be fine. The weave structure of the base fabric is preferably plain weave, lattice weave, or weft weave, and the weaving method may be air jet weave, water jet weave, rapier weave, or the like, and is not particularly limited.

In the present invention, it is preferable that the air permeability of the base fabric is as small as possible even under high pressure in order to secure the internal pressure of the airbag for 4 to 5 seconds. Air permeability is high pressure 2
It is preferably 1.0 cm ³ / cm ² / sec or less at 00 kPa, more preferably 0.5 cm ³ / cm ² / sec or less,
More preferably, the measurement limit is 0.1 cm ³ / cm ² / s
ec or less is desirable.

In order to suppress the air permeability under a high pressure, the minute amount of air permeability processing includes wet heat treatment, calendering, resin dipping, coating, laminating, or a composite processing of the above processing. Etc., and among them, it is more preferable to coat the resin. In the case of coating, the resin does not need to be particularly limited, and a commonly used resin can be used. For example, chloroprene, cross-sulfonated polyolefin, silicone rubber, polyamide elastomer, polystyrene butadiene rubber, nitrile rubber,
Fluorine rubber, polyurethane and the like can be used, and among them, silicone rubber having heat resistance, cold resistance and flame retardancy is particularly preferable. Further, the resin may contain known thickeners, flame retardants, fillers, heat-resistant agents, antioxidants, adhesives, catalysts, crosslinking agents, pigments, viscosity stabilizers, and the like.

In the present invention, the method of coating the resin is not particularly limited, and may be a conventional coating method such as an existing knife coat, roll coat, reverse coat, or the like.
A spray method, a laminating method such as a dry laminating method, a wet laminating method, and an extruding laminating method can be used. The base cloth before coating the resin may be scoured or non-scrutinized as long as it is combined with a resin formulation in which the cured resin is not easily separated from the base cloth.

As described above, in order to achieve bursting strength, folding compactness, and low frictional abrasion in an airbag, the present invention provides a base fabric used for a window-side airbag and an occupant-side airbag. Excellent by rupture the rupture strength of the base cloth used for the base cloth, further sew the coating surfaces of the base cloth to the inside of the bag, and seal around the sewn area with resin before or after sewing. Airbag can be obtained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples. In addition, the measuring method, the evaluation method, etc. are as follows. (1) Thickness of base fabric According to JIS L-1096.

(2) Air permeability of the base cloth Air pressure of 200 kPa is applied from the resin-coated surface of the base cloth to pass through a base cloth area of 60 mmφ and open to the atmosphere. The standard flow rate of passing air was measured using a flow meter. (3) Tensile strength and tensile elongation of base fabric According to JIS L-1096 (labeled strip method).

(4) Tear strength of base fabric According to JIS L-1096 (single tongue method). (5) Burst strength of base fabric According to JIS L-1096 (constant speed elongation method). (6) Surface roughness (SMD) of base fabric by KES measurement Using a surface tester (KES-FB4), standard conditions (The
Standardization and Analysis Of Hand Evaluation, 2nd
Ed.S. Kawabata, The Textile Machinery Society of Ja
pan, 1980), a coated cloth having a width of 20 cm and a length of 20 cm was measured.

(7) Average bending stiffness of base fabric by KES measurement (B) Using a pure bending tester (KES-FB2), a coating fabric was used, and the width was 5 cm and the length was 10 cm. It was measured. (8) Feeling of contact with the face The face was brought into contact with the coating cloth and moved to evaluate the degree of abrasion.

○: No friction pain, ×: Friction pain (9) Folding height As an evaluation of the compactness of an airbag, the evaluation was performed on the side of the window.
And the occupant side coating cloth to 15cm in width and 50cm in length
Cut, align the coating surfaces, and fold three
After forming the three bent parts on one side, contact pressure
0.98 N / cm ^TwoNo. of PEACOK. 207 da
The thickness (mm) was measured with an ear gauge.

Example 1 Nylon 66 chips containing 95.5% sulfuric acid relative viscosity ηr 2.95 containing 65 ppm of a copper-based heat stabilizer as copper in a polymer were melt-spun with an extruder-type spinning machine. After the yarn oil was applied, the yarn was hot-drawn to obtain a 155 dtex / 48 filament yarn (A) and a 470 dtex / 70 filament yarn (B).
Each of the obtained yarns had a strength of 8.2 cN / dtex, a boiling water shrinkage of 7.5%, and an oil adhesion of 0.8 wt%.

A warp obtained by adhering 0.8% by weight of warping oil S1700 (manufactured by Ryo Kagaku Co., Ltd.) to these yarns, a weft without warping oil, and two types of greige using an air jet loom. I got Weaving density of greige
Weft) is 89 × 89 / 2.5 using yarn (A)
4cm, 51 × 51 / 2.5 using thread (B)
It was 4 cm.

These scourers were heat-set at 170 ° C. without scouring, and then a silicone resin was coated on one side by knife coating. 25 g / m ^{2 for the} woven fabric using the yarn (A) and 50 g for the woven fabric using the yarn (B)
/ M ² , and heat-treated in a dryer at 180 ° C. for 3 minutes. For the occupant side, a woven fabric using the yarn (A) with a woven density of 91 × 91 / 2.54 cm, and for the window side, a woven fabric using the yarn (B) with a woven density of 53 × 53 / A 2.54 cm base fabric was obtained.

As the silicone resin, a mixture of 100 parts by weight of "LR6200A / B" and 0.5 parts by weight of "FL Red" manufactured by Asahi Kasei Wacker Co., Ltd. was used. "KE4" manufactured by Shin-Etsu Chemical Co., Ltd. was attached to the airbag-shaped sewing portion on the resin-coated side of the base fabric using the yarn (B).
5T "RTV resin is coated 15mm in width and 0.1mm in thickness,
After the resin side of the base cloth using the yarn (A) was put thereon and the resin was cured, the resin was sewn into an airbag shape and cut to form an airbag.

Burst strength of base fabric used for airbag, K
Table 1 shows the physical properties such as bending rigidity and surface roughness by ES measurement. Example 2 Under the conditions shown in Table 1, a base fabric and an airbag were prepared in the same manner as in Example 1. The results are shown in Table 1.

[Comparative Example 1 and Comparative Example 2] Under the conditions shown in Table 1, a base fabric and an airbag were prepared in the same manner as in Example 1. The results are shown in Table 1.

[0032]

[Table 1]

Table 1 shows the following. Comparative Example 1
Is that the base fabric using 470 dtex yarn is used on both sides of the airbag, so the burst strength of the base fabric on the window side is strong, but the folding height of the bag is high and the average bending rigidity (B)
, The compactness is inferior. Further, since the surface roughness (SDM) of the base cloth on the occupant side is high, there is frictional pain with the face, and it is not suitable as an airbag.

In Comparative Example 2, both sides of the airbag were 155
Since the base fabric using dtex yarn is used, the average bending rigidity (B) is small, the compactness is good, and the surface roughness (SDM) is low, so there is no frictional pain with the face.
However, the bursting strength of the base fabric on the window side is low, so that it is not suitable for an airbag. On the other hand, the airbag of the present invention does not have the above-mentioned drawbacks, and is extremely excellent.

[0035]

The airbag of the present invention exhibits a compact folding storage property, the base cloth on the window side has a high bursting strength, so that it is difficult to tear, and the base cloth on the occupant side has a low surface roughness, so that the face is in contact. In addition, it has an excellent feature that scratches can be prevented.

Continuation of the front page (72) Inventor Fumiaki Ise 6-4100 Asahicho, Nobeoka-shi, Miyazaki Asahi Kasei Corporation F term (reference) 3D054 CC26 CC30 CC45 CC50 FF17 FF18 4L033 AA08 AB05 AC02 AC15 CA50 CA59 CA68 4L048 AA24 AB07 CA11 CA12 CA13 CA15 DA25 EA01

Claims (3)

[Claims] Claims: 1. A window-side base cloth having a bursting strength higher than that of an occupant-side base cloth, wherein the base cloth is composed of two or more base cloths made of a woven fabric having a cover factor of 1800 or more made of a polyamide fiber. An airbag characterized by the following. 2. The average bending stiffness (B) of the occupant-side base cloth measured by KES is 0.5 to 8 mN in both the warp direction and the weft direction.
Air bag according to claim 1, wherein the cm is ² / cm. 3. The airbag according to claim 1, wherein the surfaces on the resin-coated side are sewn together with a resin-coated cloth.