JP2000170079A - Cloth for air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain cloth for an air bag, capable of readily acquiring the habit of folding and excellent in folding workability and housing property by applying a specific amount of coating agent to a base fabric made of a synthetic fiber and keeping bending hysteresis in a specific value or above. SOLUTION: This cloth for air bag is obtained by weaving a base fabric made of a synthetic fiber and having 1,700-2,100 cover factor, e.g. a plain weave obtained by driving polyamide 66 yarns having 420 denier fineness each in 44 numbers/inch as weft and warp and applying a coating agent of a silicone rubber in an amount of <=20 g/m2 expressed in terms of solid content to one side of the plain weave. In the cloth for air bag, bending hysteresis measured by KES-FB-2 is >=0.55 gf.cm/am based on average bending hysteresis in two directions mutually perpendicular in plane of the coated cloth, e.g. in warp direction and weft direction of woven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag cloth which is a cloth constituting various airbags such as an airbag for a driver's seat and an airbag for a passenger's seat. More specifically, the present invention relates to an airbag cloth that tends to be folded.

[0002]

2. Description of the Related Art In general, an airbag is stored in a folded state in a storage portion provided in a central portion of a steering wheel of a vehicle or an instrument panel, and is provided at the time of a vehicle collision. In addition, the gas generated by the inflator is deployed and expanded into the vehicle compartment to receive the occupant.

As a cloth for an airbag for such an airbag, a woven cloth made of a synthetic fiber such as a polyamide fiber is generally used. Since it inflates and receives the occupant, the airbag cloth is required to have gas impermeability. Also, it is necessary to prevent the yarn constituting the cloth from the cutting terminal formed by the cutting during the production of the airbag from fraying. Therefore, conventionally, as an airbag cloth, a coated cloth formed by coating a woven cloth with a rubber coating agent such as silicone rubber has been used.

[0004] However, the coated cloth has a problem that it is hard to be folded due to the rubber elasticity of the coating layer, and therefore, the workability of folding and storing the airbag in the case is low.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an airbag cloth of a coated cloth which is liable to be folded.

[0006]

The cloth for airbags of the present invention is a coated cloth obtained by coating a coating agent on a base cloth made of synthetic fiber, and has a bending hysteresis measured by KES-FB-2. 0.55 gf · cm on average in two directions perpendicular to each other in the plane of the coated cloth
/ Cm or more.

The average of the bending in the two orthogonal directions is, for example, the average of the bending in the warp direction and the bending in the weft direction when the base fabric is a woven fabric composed of a warp and a weft. be able to.

[0008] According to the airbag fabric, since the bending hysteresis is 0.55 gf · cm / cm or more, the airbag is easily folded, and thus the airbag can be easily folded. Further, since it is a coated cloth, it is excellent in gas non-permeability and can prevent yarn fraying due to cutting.

In the above, as the coating agent,
It is preferable to use a silicone rubber coating agent. Using a silicone rubber coating agent, compared to using a chloroprene rubber coating agent,
Excellent environmental resistance such as heat resistance.

Preferably, the coating agent is coated on only one side of the base fabric. This is because when the base fabric is coated on both sides or when the base fabric is immersed in a coating agent, the airbag fabric becomes hard and inferior in flexibility.

The coating amount of the coating agent is preferably 20 g / m ² or less in terms of solid content. By coating the coating agent with such a low basis weight,
The thickness after coating is substantially the same as the thickness of the base cloth before coating, so that a soft and inexpensive airbag cloth can be obtained, and the packaging volume of the airbag can be reduced.

The base cloth has a cover factor of 1,70.
Preferably, it is a woven fabric of 0 to 2,100. As described above, based on a relatively low-density woven fabric, by coating the coating agent with a low basis weight, the coating agent penetrates into the structure of the woven fabric surface layer and the film strength is improved,
The coating film is not easily broken when the airbag is inflated and deployed. Moreover, it is excellent in flexibility.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, matters relating to the implementation of the present invention will be described in detail.

As described above, the airbag fabric of the present invention is a coated fabric having a bending hysteresis of 0.55 gf · cm / cm or more measured by KES-FB-2. The configuration for obtaining a coated cloth having such large bending hysteresis is not particularly limited,
As described below, it can be obtained by using a relatively low-density base cloth and coating a silicone rubber coating agent on one surface of the base cloth with a low basis weight.

Here, KES-FB-2 relates to bending characteristics in a KES (Kawabata Evaluation System) which is a system for measuring basic mechanical characteristics and surface characteristics of a cloth in a low load range. The measurement is performed by the following method. That is, a sample (the length of the sample is, for example, 10 cm) is held by chucks at intervals of 1 cm, and one of the chucks is moved to obtain a curvature K = −2.5 to + 2.5c.
A pure bending having a constant velocity curvature is performed within the range of m ^-1 , and a bending moment M (gf · cm / cm) per unit length of the sample is measured, and the curvature K is 0.5 to 1.5 and −. 0.5 to -1.
Hysteresis width 2 of bending moment M in the range of 5
Find the average value of HB. This is measured by bending the sample in two orthogonal directions, for example, both in the warp direction and in the weft direction of the woven fabric, and the average of both is calculated.

Examples of the base fabric to be coated with the coating agent include polyamide fibers such as polyamide 6 and polyamide 66, polyester fibers such as polyethylene terephthalate, and woven fabrics such as aramid fibers. Is preferred.

The base fabric has a cover factor of 1,7.
It is preferable to use a woven fabric of 00 to 2,100. If it is less than 1,700, it is difficult to secure sufficient strength as an airbag, and if it exceeds 2,100, the rigidity of the base fabric becomes large and the flexibility is inferior.

Here, the cover factor is defined by the following equation (1). In the formula, "warp density" is the number of wefts per inch, and "weft density" is the number of wefts per inch.

Warp density × √ (number of denier of warp) + Weft density × √ (number of denier of weft) (1) The fineness of the synthetic fibers constituting the woven fabric is 120 to 63
The denier can be 0 denier, and in this case, the number of background shots is determined according to the fineness so as to satisfy the numerical range of the cover factor.

More specifically, the base fabric is preferably a plain woven fabric of polyamide 66 having a fineness of 420 deniers, and the number of punches is preferably 46 / inch.

As the coating agent, it is preferable to use a silicone rubber coating agent from the viewpoint of environmental resistance such as heat resistance.

For example, an alkenyl group-containing organopolysiloxane such as dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both ends is used as a main component, and fine powdered silica is used as a reinforcing filler, and further, an organohydrogenpolysiloxane or a platinum compound is cured. An addition reaction vulcanization type silicone rubber coating agent obtained by blending an agent is suitable.
If necessary, an adhesion improver such as an epoxy group-containing organosilicon compound and a flame retardant aid such as carbon black may be added to the coating agent. Further, an organic solvent such as toluene may be added so as to easily coat the thin film. In this case, the viscosity of the coating agent at 25 ° C. is 1
It is preferable to add an organic solvent so as to be in the range of 0000 to 50,000 cs.

It is preferable that the coating agent is coated on one side of the base cloth at a solid content of 20 g / m ² or less.
More preferably, the coating amount is 5 to 20 g / m in terms of solid content.
² .

By coating the above-described relatively low-density woven fabric with such a low basis weight, as shown in FIG. 1, the coating film is formed to such an extent that the texture of the woven fabric remains on the coated surface. It is formed along the unevenness of the woven fabric, and the thickness after coating is substantially the same as the thickness of the woven fabric before coating. Specifically, the thickness of the coated cloth is 1.00 to 1.
04 times. Thereby, a soft and inexpensive airbag fabric can be obtained. In addition, the obtained coated cloth has a large bending hysteresis and thus tends to be folded, so that the airbag can be easily folded and stored in a case. Also, the packaging volume is reduced.

The coating method of the coating agent can be performed using various known coating machines such as a knife coater and a comma coater. Further, in order to cure and cure the coating agent, the coating agent may be subjected to heat treatment under an appropriate temperature condition after coating. The coated cloth thus obtained is cut into a predetermined shape and sewn so that the coated surface is on the inner surface side of the airbag, and an airbag is manufactured.

In the airbag cloth of the present invention, JI
Adhesion strength measured according to SK6328.5.3.7 is 1 kgf / cm or more, and JIS L109
6.6.19.1 It is preferred that the bristles measured by the A method be 80 mm or less in both the warp direction and the weft direction. Such adhesion strength and bending resistance can be achieved by coating the above-mentioned relatively low-density woven polyamide fabric with a silicone rubber coating material at a low basis weight.

[0027]

EXAMPLES Next, the present invention will be described specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Example 1 As shown in Table 1, as a base cloth, a plain woven cloth made of 420 denier polyamide 66 and having a driving count of 46 pieces / inch each (cover factor = 188)
5, a thickness = 0.280 mm), and a coating agent of silicone rubber was coated on one surface of the woven fabric at a solid content of 15 g / m ² by a knife coater. Here, the coating agent was composed of 23 parts by weight of dimethylpolysiloxane blocked with dimethylvinylsiloxy groups at both ends, fumed silica 7
Parts by weight, 1 part by weight of organohydrogenpolysiloxane, 0.5 part by weight of a platinum-based compound, 1 part by weight of an epoxy group-containing organosilicon compound, 0.5 part by weight of carbon black,
And 70 parts by weight of toluene and an addition reaction vulcanization type silicone rubber coating agent. After coating, the coating was dried in a dryer at 180 ° C. for 7 minutes to obtain an airbag cloth.

[0029]

[Table 1]

Regarding the obtained airbag cloth, the thickness,
The bending resistance, adhesion strength, bending hysteresis, folding habit, and packaging volume were measured. Each measuring method is as follows.

Bending resistance: JIS L1096.69.1.1 Method A Adhesion strength: JIS K6328.5.3.7 Bending hysteresis: Both bending in the warp direction and bending in the weft direction are performed according to KES-FB-2. It measured and averaged. The length of the sample was 10 cm. Folding property: 760 in diameter by cutting airbag cloth
mm circular cloths were obtained, and their peripheral portions were sewn together to form a driver's seat airbag. This airbag,
Fold it into the specified shape, vertical x width is 120mm x 150
mm, and an initial load of 3 kg was applied for 1 hour, and then the state of dispersion when the load was released was visually confirmed. In the table, ○ indicates that the degree of variation is small and the folding habit is good, and X indicates that the degree of variation is large and the folding habit is poor. Packaging volume: The driver's seat airbag was folded into left and right bellows and up and down bellows, and the volume of the folded airbag was measured. In the table, the folding volume of the airbag when the airbag cloth of Comparative Example 1 described later is used is 1
It was shown as an index as 00.

Examples 2 and 3 Using the same woven fabric and coating agent as in Example 1, in Example 2, 8 g / m ² of the coating agent was applied to the woven fabric. In Example 3, the coating agent was applied to the woven fabric. 19 g / m ² were coated to obtain airbag fabrics of Examples 2 and 3.

[0033]Comparative Examples 1-4 Comparison using the same woven fabric and coating agent as in Example 1
In Example 1, a coating agent was applied to the woven fabric at 40 g / m.², Comparison
In Example 2, a coating agent was applied to the woven fabric at 25 g / m 2. ², Comparison
In Example 3, the woven fabric was coated with a coating agent of 21 g / m 2.²Each
Then, the fabrics for airbags of Comparative Examples 1 to 3 were obtained.

Comparative Example 4 was made of polyamide 66 having 420 denier, and the number of shots was 54
Plain woven fabric per book / inch (cover factor = 221)
3, thickness = 0.322 mm) was used as an airbag cloth without being coated with a coating agent.

As shown in Table 1, the airbag fabrics of Examples 1 to 3 have a bending hysteresis of 0.55 gf · cm / cm.
cm or more, it was easy to have a folding habit, and it was easy to fold the created airbag when folding it. Also, the thickness of the airbag was substantially the same as the thickness of the woven fabric before coating, and the packaging volume of the airbag was small due to the small thickness. Further, the bending resistance was 80 mm or less in both processes, and the flexibility was excellent. Also, the adhesive strength was excellent. Further, since it is a coated cloth, the air permeability is 0, the gas is impermeable, and the yarn is not frayed by cutting when an airbag is produced.

On the other hand, the airbag fabrics of Comparative Examples 1 to 3 had a bending hysteresis of less than 0.55, so that they were less likely to have a folding habit and were difficult to fold when the produced airbag was folded. Further, since the thickness was increased by the coat, the packaging volume of the airbag was larger than in each of the examples.

The airbag fabric of Comparative Example 4 had a large bending hysteresis of 0.99 and was easily folded, but the thickness of the fiber was high because the fiber density was increased to reduce the air permeability. As a result, the packaging volume of the airbag was larger than that of each of the examples, and the flexibility was poor. Further, since the airbag fabric of Comparative Example 4 is a non-coated fabric, it is inferior in gas non-permeability,
Moreover, yarn fraying due to cutting was apt to occur.

[0038]

As described above, the airbag fabric of the present invention has a bending hysteresis of 0.55 gf · cm / cm or more even though it is a coated fabric, so that the airbag fabric is likely to have a folding habit. It is excellent in the workability of folding the bag and the work of storing it in the case, is excellent in gas non-permeability, and does not cause thread fraying due to cutting.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of an airbag cloth according to an embodiment of the present invention.

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Claims (8)

[Claims] 1. A coated cloth comprising a synthetic fiber base cloth coated with a coating agent, wherein the bending hysteresis measured by KES-FB-2 is two directions perpendicular to each other in the plane of the coated cloth. 0.55g on average
A fabric for an airbag, which has a f / cm / cm or more. 2. A coated fabric obtained by coating a coating agent on a base fabric which is a woven fabric made of synthetic fiber, comprising KES-FB.
The bending hysteresis measured according to -2 is 0.55 gf · c on average of the bending in the warp direction and the bending in the weft direction of the woven fabric.
m / cm or more. 3. A coated cloth comprising a base cloth made of synthetic fiber and a coating agent coated thereon, wherein the bending hysteresis measured by KES-FB-2 is two directions orthogonal to each other within the plane of the coated cloth. 0.55g on average
An airbag cloth having a folding habit of not less than f · cm / cm. 4. The fabric for an airbag according to claim 1, wherein the coating agent is a silicone rubber coating agent. 5. The fabric for an airbag according to claim 1, wherein the coating agent is coated on only one surface of the base fabric. 6. The coating amount of the coating agent is 20 g / m ² or less in terms of solid content.
The airbag cloth according to the above. 7. The method according to claim 7, wherein the base cloth has a cover factor of 1,700.
The airbag fabric according to claim 6, wherein the fabric is a woven fabric of up to 2,100. 8. The base fabric is made of polyamide 66 having a fineness of 420 deniers.
The airbag fabric according to claim 7, wherein the fabric is an inch woven fabric.