JPH0263949A - New air bag device - Google Patents

Abstract

PURPOSE:To aim at lightening and compacting an air bag by laminating a specific heat resistant film on the inner surface of woven or nonwoven fabric made of synthetic fiber. CONSTITUTION:In an air bag device for preventing a passenger from colliding against a steering handle, a front glass, and the like by detecting the acceleration at the time of collision of a vehicle so as to expand the air bag, the air bag is formed of a bag body made of woven or nonwoven fabric made of synthetic fiber lined with heat resistant organic films. Polyamide, polyester, polyacrylonitrile fibers which do not dissolve or decompose substantially under approximately 200 deg.C are used as the synthetic fiber. Polymer composition with the melting point of over 350 deg.C or without a melting point is used as the heat resistant organic film, that is, for example an organic film, a polyimide film, a meta or par-Aramid film, and the like are used.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a vehicle airbag device.

More specifically, the present invention relates to an airbag device that is safe, lightweight, and economical because it is laminated with a high-strength organic film that has high heat resistance and flexibility on the inside.

(Prior Art) A so-called automobile airbag device, which is used to protect occupants from the impact of an automobile collision, is attracting attention as a safety device that can replace a seat-held device, and is installed in some vehicles.

Currently, the airbands used in industrial use are made of 840dc plain woven fabric made of high-strength nylon (strength approximately 8 to 9g/d) coated with rubber such as chlorobrene or hypalon. Sa is 0.40~0
．． At 50 mm, it is quite thick, so it requires a lot of space to store inside the handle, making it difficult to maneuver and spoiling its aesthetics.

Airbags for automobiles are injected with air at high speed during a collision and inflate, causing the occupants to experience a collision. Since it is necessary to absorb and relieve air, this rubber coating has the function of momentarily trapping air inside the bang. However, in addition to the above-mentioned drawbacks, this coating does not necessarily have a sufficient level of resistance to high temperatures caused by gunpowder explosion due to expansion, and coating textiles is complicated, leading to increased costs. .

As one means for solving the problem of heat resistance, JP-A-63-78744 proposes using wholly aromatic polyamide fiber for the base fabric and silicone rubber for the rubber. As described above, it is possible to considerably reduce the size and weight by using a strong and heat-resistant material, but it is still not satisfactory and is extremely expensive.

(Problems to be Solved by the Invention) As a result of conducting studies to solve the problem of reducing the size and weight of airbags without compromising safety or economic efficiency, we found that synthetic fiber woven or The present invention was achieved by discovering that the object can be achieved by laminating a specific heat-resistant organic film on the inner surface of a nonwoven fabric.

(Means for Solving the Problems) The present invention provides an airbag device used to protect occupants from impact during a vehicle collision, in which an airbag is made of synthetic fiber woven fabric or synthetic fiber nonwoven fabric at a temperature of 350°C or higher. This airbag device is a bag body lined with a heat-resistant organic film that has or does not have a melting point.

The airbag device referred to in the present invention is also referred to as an inflatable occupant restraint device, a gas bag device, etc., and detects the acceleration of a vehicle such as a car during a collision, and controls the driver's seat, passenger seat, etc. The passenger inflates the bag installed in the front and presses the handle 1. This is a device that prevents collisions with windshields, etc. The airbag device consists of an impact detection sensor, a gas generator, and an airbag.

In the present invention, it is essential that the airbag is a woven or nonwoven fabric made of synthetic fibers lined with a heat-resistant organic film. The synthetic fibers used include polyamide (nylon), polyester, polyacrylonitrile, aromatic polyamide (aramid), polyimide, polyphenylene sulfide, polyetherimide, etc., which do not substantially melt or decompose at temperatures below about 200°C. As the woven fabric, plain weave is usually selected, but if necessary, other woven structures such as satin may be used.As the non-woven fabric, those manufactured by the so-called spunbond method, flash method, etc. are used. It will be done.

As the heat-resistant organic film, it is necessary to use a film made of a polymer that has a melting point of 350° C. or higher, or has no melting point. If an organic film made of a polymer with a melting point below 350°C is used, it will not be able to withstand the heat generated by the explosive explosion when the airbag is inflated.
This is not preferable as it may cause wear and tear.

Specific examples of organic films that can be used in the present invention include polyimide films, meta- or para-aramid films, polybenzobisthiazole films, polyetherimide films, and aromatic polyester films. Among these, para-based aramid film in particular has sufficient heat resistance, has very high strength and elastic modulus, and has excellent tear performance, as well as very good gas barrier properties, so it can be used in thin forms. This is most preferable in terms of bag storage and light weight. Here, the para-aramid film is manufactured using a polymer of the following general formula (I) or general formula (II) or a copolymer thereof.

(wherein R,, R2 and R3 are selected from
These hydrogen atoms may be substituted with functional groups such as halogen, methyl, ethyl, methoxy, nitro, and sulfone. m and n are average degrees of polymerization and are about 50 to 1000. ) Polymers other than the above-mentioned components may be copolymerized or blended with the para-aramid used in the present invention in an amount of about 20 mol % or less. Particularly preferred as the para-aramid is poly(P-phenylene terephthalamide).

The film used in the present invention needs to have high elongation and strength in order to withstand the impact force caused by airbag inflation and collision with an occupant, and preferably has an elongation of 10% or more.

The thickness of the film depends on the mechanical properties of the film, but is usually 3 to 40 μm, preferably 5 to 25 μm.
used in Using a film with a thickness of more than 100 μm improves the bag's storability and lightness.

The method of laminating the film onto the synthetic fiber woven fabric or synthetic fiber nonwoven fabric is not particularly limited. For example, the first embodiment is a method in which the film is first formed into a film and then attached to a woven or nonwoven fabric using an epoxy, acrylic, ester, or phenol adhesive.

A second method is to apply a solution of the film-forming polymer to a textile or nonwoven fabric and remove the solvent. In other embodiments, polymerization is performed directly on a woven or nonwoven fabric,
There is a method of forming a coating film by CVD.

Lamination is performed on the entire surface of the woven or non-woven fabric depending on the balance between rapid expansion and subsequent contraction when the airbag is activated.
It may be a structure in which an exhaust port is attached, or a structure in which the exhaust port is attached to a part of a woven or non-woven fabric. In the case of the former structure,
Installing an exhaust pipe at the end of the exhaust port to exhaust the gas generated when the airbag 11 is activated to the outside of the vehicle is one of the preferred embodiments in terms of improving the safety of the airbag device.

In the present invention, as the impact detection sensor, a G sensor, a radar sensor, a crash sensor, etc. can be used, and as the gas generator, a conventionally known system such as a compressed gas system, a solid fuel system, etc. can be used.

〔Example〕

The present invention will be explained below using examples. In the examples, parts and % indicate parts by weight and % by weight unless otherwise specified.

Example [Manufacture of aramid film] Poly(paraphenylene terephthalamide) polymer having a logarithmic viscosity ηinh of 5.5 was added to 99.7% sulfuric acid to give a polymer concentration of 11.5%). This]・−
The tube was kept at approximately 70'C and degassed under vacuum.

The dope had optical anisotropy and a viscosity of 4400 voids. A 1.5 m long curved pipe from the tank, through the filter, through the gear pump, to the die is maintained at approximately 70°C, and the temperature is 0.1 m.
Cast the dope onto a tantalum belt with a slit of mm x 300 mm on a mirror surface, blow air at about 90'C with a relative humidity of about 85% to make the cast dope optically isotropic, and together with the belt, It was introduced into dilute sulfuric acid at -5°C and coagulated.

The coagulated film is then peeled off from the belt and heated to approximately 40°C.
It was washed by running it in warm water. The washed film was stretched in a tenter without drying, then heat-dried at 240°C in a fixed length using another tenter, and then stretched at 390°C.
A fixed-length heat treatment was carried out at 'C. The obtained film has a thickness of 8 μm and a strength of MD: 35 Kg/mm”, T
D: 34 Kg/mm2, elongation MD: 17%,
TD: 16%, Young's modulus (MI): 1200Kg/mm
2, T D:I 300Kg/mm2.

[Manufacture of airbag installation equipment]

Using high-strength nylon 840de (strength 8.7 g/d) for the warp and weft, the above film was attached to a hand-woven fabric with a thickness of 0.380 m/m with 25 warps and wefts/1 nch using an epoxy adhesive. An airbag base fabric having a thickness of 0.405 m/m was obtained, and an airbag device having two exhaust ports was made using this fabric. The weight of the airbag was 520g, and the volume when stored was 810ml.

[Operation test of airbag device] A gas generator using a metal azide compound as a gas generating agent was attached to the airbag, and an operation test was conducted. The temperature at the gas generator outlet during gas generation was 600'C@. The desired inflation/deflation pattern was obtained, and no t-features were found in the airbag after activation.

Comparative example [Production of air bang device] High-strength nylon 840de (strength 8.7 g/d) was used for the warp and weft, and chloroprene rubber was added to a plain weave fabric with a thickness of 0.38 On+/m with a warp and weft of 25 threads/1 nch. The German AUMA Roller-11ead+Contin
One side of the above fabric was calendered using a vulcanizing machine to a thickness of 0.430m.
/m of airbag base fabric was obtained, and an airbag device with two exhaust ports was manufactured using this fabric.

The weight of the airbag was 705g, and the volume of the airbag when stored was 860ml.

[Airbag device operation test]

After performing the same operation test as in the example, when the airbag was observed, it was discovered that the chloroprene rubber in the area near the gas generator had turned black.

(Effects of the Invention) The airbag device of the present invention has a veneer bag that is lighter and smaller than those of conventionally known airbag devices, and the storage space can be reduced. In addition, its light weight saves fuel, and in particular in airbang devices for the driver's seat, the weight burden on the steering wheel shaft is reduced, making it possible to avoid making the steering wheel-related parts bulky.

Furthermore, since the parts that come into contact with high-temperature generated gas have excellent heat resistance, the airbag device has excellent safety and reliability.

Claims (1)

[Claims] In airbag devices used to protect occupants from impacts during vehicle collisions, the airbag is made of synthetic fiber woven fabric or synthetic fiber nonwoven fabric that has a melting point of 350°C or higher or a heat-resistant organic material that does not have a melting point. An airbag device that is a bag body lined with film.