JP2705307B2 - Airbag - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an airbag which inflates a wheel, for example, in the event of a car collision, absorbs the impact of a seated occupant, and protects it.

[Prior Art] In recent years, the practical use of airbags for ensuring the safety of occupants in automobiles has been rapidly increasing.

In the event of a car collision, the sensor receives a shock from the collision and generates high-pressure gas, which inflates the airbag instantaneously.
It is intended to protect the occupants, especially the face.

Conventionally, plain fabrics using 400-1000 denier nylon 6.6 filament yarns for airbags, and synthetic rubbers such as chloroprene and chlorosulfonated olefins to improve heat resistance, flame retardancy and air barrier properties It was made by cutting and sewing a base fabric that was coated with an elastomer such as rubber or natural rubber and laminated. The airbag is stored in a narrow space such as a steering wheel or an instrument panel until immediately before activation, and the smaller the storage volume is, the better, and the softer, lighter and thinner the base cloth is, the better. . However, in order to improve the various performances of the conventional airbag, the elastomer is applied and laminated with a certain thickness, so that the airbag is thick and heavy.
In addition, the texture is usually hard, the foldability is poor, the storage capacity is large, and the impact on the human body, especially the face, is strong when instantaneous expansion due to high temperature and high pressure gas. In response to the rebound, they sometimes collided with vehicle structures and injured them.

In order to solve such a problem, JP-A-64-70247 discloses that one or both surfaces are press-pressed and pressed, and the resulting fabric has an air permeability of 5 cc / cm ² / sec or less and a basis weight of 250 g / m 2. We propose a base fabric for airbags of ² or less.

[Problems to be Solved by the Invention] However, since the base fabric in the above-mentioned prior art is filled with the woven yarn of the entire base fabric and pressed to reduce the air permeability to 5 cc / cm ² / sec or less, The combined yarns are crimped to each other, the versatility of the yarn is extremely poor and the paper-like feel is hard (rigidity: 90-110mm). Not only the storage volume is large, but also the instantaneous inflation of the airbag. In this case, there is a disadvantage that the impact on the human body, especially on the face is large.

On the other hand, the inventors of the present invention have disclosed in the specification of Japanese Patent Application No. 1-163140 that one side of a woven fabric composed of two or more fiber components having a thermal melting difference has a resin coating formed by a fiber component that melts at a relatively low temperature. Is constituted, the surface on the opposite side of the resin coating surface is a fiber component that melts at a relatively low temperature and a fiber component that melts at a relatively high temperature or an infusible fiber component is substantially mixed in a fibrous form. A non-breathable sheet is proposed. However, this non-breathable sheet also has the features of being lightweight, having excellent bending resistance and bending resistance, and having high tear strength and very low elongation. Because it is composed of a molten resin coating of the fiber component that melts, the texture is hard (rigidity: 150 mm or more), and when the sheet is applied to an airbag, not only the storage volume is large,
The instantaneous inflation of the airbag has the disadvantage that the impact on the human body, especially the face, is large.

In view of the drawbacks of the conventional airbag, an object of the present invention is to maintain the air-blocking performance of the airbag, while being lightweight, thin and soft in texture, excellent in storage, and instantaneous of the airbag. It is an object of the present invention to provide an airbag having a small impact particularly on the face when inflated.

[Means for Solving the Problems] The present invention has the following configuration to achieve the above object.

That is, the airbag of the present invention is a woven fabric using a composite filament yarn composed of two or more fiber components having a softening temperature difference, and at least one of the fiber components softened at a low temperature among the fiber components of the woven fabric. A part thereof is softened and pressure-bonded, and the stiffness of the woven fabric measured by JIS L-1096 (45 ° cantilever method) is 80 mm or less.

[Function] The airbag of the present invention has a characteristic that the stiffness measured by JIS L-1096 (45 ° cantilever method) is 80 mm or less, preferably 30 to 70 mm, and the feel is extremely soft. This feature makes it easy to soften the easily softening fiber component and uses it as a pressure-bonding component, so that the curing of the fabric can be suppressed, and the permeability of the fabric is a value suitable for airbags, preferably 1 cc / cm ² / sec or less, more preferably about 0.5 cc / cm ² / sec or less.

This feature of the invention is achieved by a composite filament yarn consisting of two or more fiber components having a softening temperature difference. Having a softening temperature difference means that the temperature of softening by heat is different, and specifically, at least two kinds of fiber components, that is, a low-temperature softening fiber component (A) that softens at a relatively low temperature. And a fiber component (B) which softens at a relatively high temperature with respect to the fiber component or is non-softening. However, in the present invention,
For example, one or both of the components (A) and (B) may be contained in plural.

The composite filament yarn in the present invention is a filament yarn in which the fiber component (A) and the fiber component (B) are independent of each other, and are a mixture of these fibers, interwoven and interwoven, or a mixture of the respective fiber components. 1 polymer component
It refers to two types of yarns, which are conjugate fibers that are adjacent and joined to each other in a book filament.

As the type of the mixed fiber, for example, a uniform mixed fiber type, a bimetal type that is arranged to be biased to one side, or a fiber component (B) arranged on the core side and a fiber component (A) arranged on the sheath side. The core-sheath type can be exemplified, and among them, the latter bimetal type and the core-sheath type which are arranged unevenly are preferable.

Examples of the conjugate fiber include a polymer having a softening temperature difference, a bimetal type or a three-layer laminate type in which a fiber (A) component is laminated on both sides of a fiber (B) component, and a fiber (B) component. A core-sheath type in which the fiber (A) component is disposed on the core side on the sheath side is preferable.

In any case of the composite filament yarn, the fiber component (A)
Is softened and pressure-bonded to the adjacent fiber component (A) or fiber component (B), and exhibits the required air-blocking performance as an airbag. Therefore, a bimetal type or a core-sheath type is more preferable since the mechanical strength may be reduced.

The fiber components in the present invention include nylon 6, nylon 6.6, nylon 12, nylon 4.6 and nylon 6.
Copolymers of nylon and nylon 6.6, polyamides obtained by copolymerizing nylon with polyalkylene glycol, dicarboxylic acid, amines, etc., homopolyesters such as polyethylene terephthalate and polybutylene terephthalate, and acid components constituting repeating units of polyesters such as isophthalic acid acid,
Polyamide copolymerized with aliphatic dicarboxylic acid such as 5-sodium sulfoisophthalic acid or adipic acid, aramid fiber, rayon fiber, and ultra-high molecular weight polyethylene represented by a copolymer with paraphenylene terephthalamide and aromatic ether Fibers, sulfone fibers such as paraphenylene sulfone and polysulfone, polyetherketone fibers, carbon fibers, glass fibers, and the like can be used.

In the present invention, a composite filament yarn is formed by using two or more fiber components having a softening temperature difference among these fiber components.

As the fiber component (A) to be used, those which are easily softened and easily press-bonded to the fiber component (B) are preferable, as well as basic properties such as mechanical properties and thermal properties necessary for an airbag. Further, the difference in softening temperature of the fiber component (B) is preferably higher than that of the fiber component (A) by 20 ° C. or more, more preferably 30 ° C. or more. The compounding ratio of the fiber component (A) and the fiber component (B) differs depending on the mixed fiber, the interwoven, the interwoven or the composite fiber system, but preferably the weight ratio (A /
B) is preferably in the range of 5/95 to 60/40, more preferably 10/90 to 30/70.

If the proportion of the fiber component (A) is less than 5%, it is difficult to obtain a sufficiently softened and crimped product, and if it exceeds 60%, the amount of the softened and crimped component is too large and the mechanical strength as an airbag is high. Tend to lead to a decrease in

The fineness of the composite filament yarn is preferably from 50 denier to 1000 denier, and more preferably from 200 denier to 850 denier from the viewpoint of weight reduction.

The woven fabric used in the present invention is a plain weave, a satin weave, or a bunbun weave.
Although it is possible to use those having a variable texture such as an original texture and a multiaxial texture, plain weave is preferred from the viewpoints of isotropic mechanical strength and thinning.

The basis weight of the woven fabric is preferably 200 g / m ² or less from the viewpoint of weight reduction, thinning and softening of the texture. If it exceeds 200 g / m ² , the storage volume is large, which is not preferable.

As a method for softening / compressing the low-temperature softening fiber component constituting the woven fabric, a hot air heating method, a heat calendering method, or the like can be appropriately used. The heating temperature depends on the fiber component (A) used.
Can be appropriately determined by the softening point of The heating time is preferably within a range in which the air-blocking property required for the airbag is obtained, and a condition as short as possible is preferable in terms of softening the texture.

[Examples] Next, the present invention will be further described with reference to examples.

The physical properties in the examples were measured by the following methods.

(1) Weight The mass per unit area of JIS L-1096 was measured.

(2) Thickness Measured according to JIS L-1096.

(3) Air permeability Measured according to JIS L-1096 (A method).

(4) Bending resistance Measured according to JIS L-1096 (45 ° cantilever method).

(5) Impact on the human body The softened and crimped fabric is cut and sewn to produce a 34.5 cm radius circular airbag, and a 4 cm radius hole is made as an inflator attachment part. Next, as shown in FIG. 1, an ultra-thin rubber balloon is put in the airbag,
Inflate until 0.2 kg / cm ² . Next, a 500 g lead pendulum attached to the end of a 1-m long string is placed in a natural hanging state, and the pendulum and the center of the airbag are set close to contact with each other. 45 °
From the airbag at the position, and release from it to collide with the airbag. Measure the angle at which the impacted pendulum returns due to the rebound of the airbag. This return angle was evaluated as the degree of impact.

Examples 1-3, Comparative Examples 1-4 Nylon 6 having a softening temperature of 180 ° C (melting point: 215 ° C) was placed on the outer layer, and nylon 6.6 having a softening temperature of 232 ° C (melting point: 250 ° C) was placed on the inner layer. Spinning and drawing from different holes, the first filament of nylon 6 and nylon 6.6 having the same single yarn fineness and the composite filament yarn of 420 denier 70 filament
The mixed fiber shown in the table was obtained.

Next, the mixed yarn is used for the warp and weft yarns, and after obtaining a plain weave of 46 warp yarns and a weft yarn density of 46 yarns / inch, scouring and drying are performed in a usual manner, and the heat is formed by a pair of metal rolls. Using a calender, at a linear pressure of 10 kg / cm, the temperature of the heating roll was changed as shown in Table 2, and softening and pressure bonding were performed.

On the other hand, as Comparative Example 3, nylon 6.6 was melt-spun,
A 420 denier 70 filament yarn was obtained. The filament yarn is used for warp yarn and weft yarn, and after obtaining a plain weave of 46 yarns / inch in both warp yarn density and weft yarn density, scouring is carried out by a usual method.
Dried, set in the middle. Next, using a heat calender composed of a pair of metal rolls, pressure and pressure treatment were performed at a roll heating temperature of 160 ° C. and a linear pressure of 50 kg / cm.

Further, as Comparative Example 4, an airbag was obtained in which chloroprene rubber was applied at 101 g / m ² to the fabric in the intermediate set similar to Comparative Example 3. The results of evaluating these airbags are
It is as described in the table.

As is clear from Table 2, the airbag of the present invention has:
While maintaining the required air-blocking properties, it was lightweight, thin and soft in texture, and had little impact on the human body.
On the other hand, in the case of Comparative Example 2 where the heating roll temperature exceeded the melting point of the low-temperature softened fiber component, that is, the fusion-bonded one had a hard feel and a large impact. Further, the fabric obtained by simply pressing and pressing the woven fabric of Comparative Example 3 consisting of nylon 6.6 alone yarn also had a strong hand and a large impact. On the other hand, the current airbag to which the chloroprene rubber of Comparative Example 4 was applied was heavy, had a thick ground, had a hard feel, and had a large impact.

Example 4 Polyethylene terephthalate obtained by copolymerizing 16% by mole of isophthalic acid was melt-spun, and softened at 190 ° C. and 60 deniers 1
0 filament yarn was obtained. On the other hand, polyethylene terephthalate was melt spun to obtain a 360 denier 60 filament yarn having a softening temperature of 235 ° C. The low temperature softened fiber and the high temperature softened fiber were mixed to obtain a composite filament yarn of 420 denier 70 filaments. Next, the composite filament yarn is used for the warp yarn and the weft yarn, and after obtaining a plain weave of 45 yarns / inch both in the warp yarn density and the weft yarn density, scouring and drying are performed by a usual method, and then a hot calender comprising a pair of metal rolls is used. Was used to obtain an airbag pressurized and pressed at a roll heating temperature of 190 ° C. and a linear pressure of 15 kg / cm.

 Table 3 shows the results of evaluation of the airbag.

Comparative Example 5 Polyethylene terephthalate was melt spun and the softening temperature
A 420 denier 70 filament yarn at 235 ° C. was obtained. The filament yarn was used for warp yarns and weft yarns. After obtaining a plain weave with a warp yarn density and a weft yarn density of 45 yarns / inch, an airbag subjected to a heat calender treatment under the same conditions as in Example 4 was obtained.

 Table 3 shows the results of evaluation of the airbag.

As is clear from Table 3, the airbag of the present invention is:
While maintaining the required air-blocking properties, it was lightweight, thin, soft in texture, and small in impact. On the other hand, the yarn using the polyethylene terephthalate single yarn of Comparative Example 5 had a hard feel and a large impact.

[Effects of the Invention] According to the present invention, when the airbag is momentarily inflated, it is possible to reduce the impact particularly on the face. An airbag with a low rate can be obtained. At the same time, the steering wheel and instrument panel can be reduced in size because they are lightweight, thin, soft in texture, and excellent in storage. In addition, the airbag according to the present invention is less expensive to manufacture than conventional airbags, and can promote the spread of occupant protection systems using airbags.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a method for measuring the impact property of an airbag.

Claims (3)

(57) [Claims] 1. A woven fabric comprising a composite filament yarn comprising two or more fiber components having a softening temperature difference,
At least a part of the fiber component that softens at a low temperature among the fiber components of the woven fabric is softened and pressed, and JIS L-1096
The stiffness of the woven fabric measured by (45 ° cantilever method) is 80.
An airbag characterized by being not more than mm. 2. The airbag according to claim 1, wherein the difference in softening temperatures of the fiber components constituting the composite filament yarn is 20 ° C. or more. 3. The airbag according to claim 1, wherein the weight of the woven fabric in which at least a part of the fiber component is softened / compressed is 200 g / m ² or less.