JP3480585B2 - Base fabric for airbag - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorbing airbag for ensuring safety. For more details,
The present invention relates to an airbag having excellent burst resistance when the bag is activated and inflated.

[0002]

2. Description of the Related Art In recent years, an airbag system has been put into practical use as a safety protection device for automobiles. Usually, this airbag is formed by forming a heat-resistant polymer coating on one side of a flat woven fabric, cutting it out in a circular shape, stacking the coating so that the coatings face each other, and sewing the surrounding area. Such a bag is rapidly inflated by high-pressure gas supplied from a gas generator due to a shock such as an accident, restrains an occupant, and at the same time discharges gas in the airbag to reduce reaction force to the occupant. For the purpose, small holes are provided in the airbag.

However, when the occupant collides with the bag, the internal pressure in the bag instantaneously increases due to the pressure from the human body of the occupant, and the bag must be able to withstand this internal pressure with a sufficient margin. To meet this requirement, the burst rupture strength of the bag can be increased to some extent by increasing the yarn denier of the filaments that make up the base cloth. On the other hand, the airbag has a small impact on the human body at the time of collision. The yarn denier is required, and as a result, it is desired that the yarn denier be as thin as possible. Under such circumstances, there has been a trend toward using a yarn denier of 500 denier or less for the base fabric for airbags in recent years, but in the prior art, the above-mentioned fear of airbag rupture cannot be eliminated. There was

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems of the prior art, the present invention provides an air bag coated base cloth which, when made into an air bag, has excellent burst strength and flexibility. It is the one we are trying to provide.

[0005]

[Means for Solving the Problems] Means for solving the above problems, that is, the present invention, is a nylon of 500 denier or less.
A base fabric in which at least one side of a woven fabric of 66- fiber multifilament is coated with a resin, and the sliding resistance of the base fabric is 8 in both the warp direction and the weft direction.
It is a base fabric for an airbag, which is characterized in that it is about 20 mm.

Examples of synthetic fiber multifilaments having a denier of 500 or less include, but are not limited to, nylon 6, nylon 66, polyester, aramid and wholly aromatic polyester.

The strength of these multifilament yarns is
5 g / d or more, preferably 6 g / d or more is good in terms of airbag characteristics. Further, the fineness of these filament yarns needs to be selected so as to withstand the burst strength as an airbag, but the upper limit is 500 denier. If it exceeds this, the flexibility becomes insufficient, which is not preferable. Also,
If the fineness is less than 200 denier, the burst strength of the airbag becomes low, and the safety of the crew cannot be guaranteed.

As the design of the woven fabric of the present invention, plain weave, mat weave, twill weave, and other varied designs can be used. Among such woven fabrics, plain weave, which has excellent mechanical properties, is preferable.

Further, the woven fabric of the present invention is coated with a heat-resistant polymer film on at least one side of the woven fabric in order to maintain heat resistance and airtightness which are necessary properties as an airbag. As the heat-resistant polymer, for example, a heat-resistant synthetic resin such as chloroprene rubber, chlorosulfonated olefin rubber, silicone rubber, fluororubber, vinyl chloride or chlorinated olefin, or natural rubber can be used. Furthermore, as the heat-resistant polymer film, synthetic resins containing usual organic or inorganic flame retardants such as phosphorus-based flame retardants and halogen-based flame retardants, such as urethane resins and acrylic resins, can be used.

The heat-resistant polymer can be formed into a film by a conventional coating method such as knife coating or roll coating, an extrusion laminating method in which a heat-melted heat-resistant polymer is directly coated on a woven fabric, and a heat-resistant film formed into a film. It is possible to use a dry laminating method in which a hydrophilic polymer is laminated with an adhesive, and further a method of containing it in a synthetic resin solution containing a flame retardant. The coating amount of such a coating is not particularly limited as long as it is resistant to high temperature and high pressure gas and maintains airtightness, but a smaller amount is preferable in terms of storability. Generally, the coating amount of the coating is 15 g / m ^{2 to} 45 g
/ M ² is preferred.

It is important that the woven fabric having such a coating has a sliding resistance of 8 mm or more and 20 mm or less. Here, the slipping resistance means that the woven fabric having the above-mentioned coating is nylon 66 sewing thread NO. No. 5 was used as a suture thread, and was prepared according to JIS L1096 6.21 A method except that it was sutured with a DPx17 Size 20 sewing machine needle, and the sliding length when 120 kgf tensile tension was applied was measured. .

In the present invention, it is important that the sliding resistance is in the above range. If the sliding resistance is 8 mm or less, a high burst strength of the airbag cannot be obtained, while
When the sliding resistance is 20 mm or more, the stitched portion becomes weak and the burst strength is reduced. Although the reason why such an effect is obtained is not clear, when the slipping resistance is in the above range, a proper slipping occurs at the sutured portion of the outer periphery of the bag before the bag bursts, and this slipping of gas energy This is probably because part of it is absorbed and the outflow of gas from the slippage part is combined with the mitigation of the impact force acting on the base fabric. The sliding resistance can be adjusted within the above range by the woven density of the woven fabric, the strength of the heat-resistant polymer coating applied on at least one side, and the adhesive strength.

[0013]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In addition, the measurement of each measured value in the examples was performed by the following method. Tensile strength: Using a sample with a width of 3 cm, JIS L-109
6 6. Tensile strength was measured by the 12 A method. Sliding resistance: The base cloth is nylon 66 sewing thread NO. JIS L1096 6. Other than using No. 5 as a suture thread and suturing with a sewing machine needle of DPx17 Size 20. 21A
The length of slippage when a tensile tension of 120 kgf was applied to the sample prepared according to the method was measured. Bag burst strength: Using a bag development equipment manufactured by Ito Seiki, the burst pressure of the bag was measured when nitrogen was ejected from the nitrogen tank having a volume of 31 liters and a gas pressure of 2.2 MPa into the bag.

Examples 1 and 2 and Comparative Examples 1 and 2 A 420 denier nylon 66 yarn composed of 136 filaments was prepared into yarns having different amounts of oil adhesion, and these yarns were used to obtain a weaving density. A plain weave fabric having a warp yarn direction of 41 yarns / inch and a weft yarn direction of 41 yarns / inch was woven by a rapier loom to prepare fabrics having different adhesiveness to silicone rubber. Then, the entire fabric was coated with a silicone rubber at a thickness of 40 g / m ² to obtain a base fabric for airbags having sliding resistance as shown in Table 1.
Using the obtained base cloth, airbags having an internal volume of 60 liters were produced, and the burst strength of these bags was measured. Table 1
As shown in FIG. 3, the base fabrics of Examples 1 and 2 whose sliding resistance is in the range of the present invention have burst pressures outside the ranges of Comparative Examples 1 and 2 even though the strengths of the base fabrics are almost the same. It can be seen that it is improved by about 20 kPa as compared with the cloth.

[0015]

[Table 1]

[0016]

Industrial Applicability According to the present invention, it is possible to provide a coating base fabric for automobile airbags which is flexible, has high burst strength, and is more excellent in safety.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-319194 (JP, A) JP-A-5-78946 (JP, A) JP-A-5-5890 (JP, A) International Publication 94/020334 (WO, A1) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60R 21/16

Claims (2)

(57) [Claims] 1. A base fabric comprising a woven fabric of nylon 66 fiber multifilaments having a denier of 500 denier or less, which is coated with a resin on at least one side thereof, and has a sliding resistance of 8 to 8 in both the warp and the weft direction. Base fabric for airbags, which is 20 mm. 2. Nylon 66 fiber multifilament is 2
The airbag according to claim 1, wherein the airbag has a denier of 00 to 500.
Use base fabric.