Airbag and a preparation method thereof

Abstract

The present invention relates to an airbag including an inflating part having gas inflatability, a non-inflating part supporting the inflating part, a combined part constituting a boundary between the inflating part and the non-inflating part, and an ultrasonic fusion bonded part located between the combined part and the end part of an inflator from which a gas at a high pressure spurts when a car crashes, and a preparation method thereof.

Claims

1. An airbag, including an inflating part having gas inflatability, a non-inflating part supporting the inflating part, a combined part constituting a boundary between the inflating part and the non-inflating part, and an ultrasonic fusion bonded part located between the combined part and an end part of an inflator from which a gas at a high pressure spurts when a car crashes, wherein a width of the ultrasonic fusion bonded part is 0.1 to 2 cm.

2. The airbag according to claim 1, wherein at least one fabric selected from the group consisting of a nylon-based fabric, a polyester-based fabric, a polyolefin-based fabric, and an aramid-based fabric is used in the airbag.

3. The airbag according to claim 1, wherein a fabric having a weave density of 80 yarns/inch or less is used in the airbag.

4. The airbag according to claim 1, wherein a fabric including yarns of which total fineness is 210 to 840 denier is used in the airbag.

5. The airbag according to claim 1, wherein a shortest distance between the ultrasonic fusion bonded part and the combined part is 0.1 to 30 cm.

6. The airbag according to claim 1, wherein a length of the ultrasonic fusion bonded part is 1 to 30 cm.

7. The airbag according to claim 1, wherein the ultrasonic fusion bonded part has a shape of a full line, a dotted line, a curved line, a zigzag, an arrowhead, or multiple lines.

8. A method of preparing an airbag, including steps of: preparing a double-layered fabric including an inflating part having gas inflatability, a non-inflating part supporting the inflating part, and a combined part constituting a boundary between the inflating part and the non-inflating part; and forming an ultrasonic fusion bonded part at the double-layered fabric between the combined part and the end part of an inflator from which a gas at a high pressure spurts when a car crashes, wherein the step of forming the ultrasonic fusion bonded part is carried out by using ultrasonic waves at a frequency of 15 to 25 kHz.

9. The method of preparing an airbag according to claim 8, wherein the step of forming the ultrasonic fusion bonded part is carried out under a condition of a press pressure of 30 to 60 psi.

10. The method of preparing an airbag according to claim 8, wherein the step of forming the ultrasonic fusion bonded part is carried out for a fusion time of 0.25 to 6seconds.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic drawing showing the airbag cushion to which the ultrasonic fusion bonding is applied according to one embodiment of the present invention.

(2) FIG. 2 is a schematic drawing showing a device for monitoring the internal pressure of the airbag according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENT

(3) Hereinafter, preferable examples are presented for understanding the present invention. However, the following examples are only for illustrating the present invention, and the present invention is not limited to or by them.

EXAMPLES 1 To 4

(4) Side-curtain-type airbags were prepared by a one piece weaving (OPW) method in a Jacquard loom, according to the conditions disclosed in the following Table 1.

(5) Particularly, ultrasonic fusion bonded parts were formed in the shape of a full line between the combined part and the end part of an inflator from which a gas at a high pressure spurts when a car crashes, as illustrated in FIG. 1.

COMPARATIVE EXAMPLE 1

(6) A side-curtain-type airbag was prepared substantially according to the same method as in Example 1 by a one piece weaving (OPW) method in a Jacquard loom, except that separate ultrasonic fusion bonded parts were not formed, as disclosed in the following Table 1.

COMPARATIVE EXAMPLE 2

(7) A side-curtain-type airbag was prepared substantially according to the same method as in Example 3 by a one piece weaving (OPW) method in a Jacquard loom, except that the warp fineness and the weft fineness were changed and separate ultrasonic fusion bonded parts were not formed, as disclosed in the following Table 1.

(8) The properties of the airbags prepared according to Examples 1 to 4 and Comparative Examples 1 and 2 were measured by the following methods, and the results are listed in the following Table 1.

(9) 1) Evaluation on Internal Pressure

(10) After preparing side-curtain-type car airbags by using the fabrics for an airbag prepared in Examples 1 to 4 and Comparative Examples 1 and 2, internal pressure maintenance performance of the airbag was measured by the following method at room temperature without separate aging.

(11) As illustrated in FIG. 2, the airbag was inflated by instantaneously injecting compressed nitrogen gas at 16 bar into the airbag, and the change of the internal pressure of the airbag was observed by time. The maximum pressure when the gas was instantaneously injected and the internal pressure of the airbag after 6 seconds were measured, respectively.

(12) 2) Evaluation on Fusion Bonding

(13) Whether fusion bonding was formed or not was evaluated by directly pulling the fusion bonded part. When the fused part was bonded as the combined part (seam), it was evaluated that fusion bonding was formed (expressed as Yes), and when the part was not bonded and was separated, it was evaluated that fusion bonding was not formed (expressed as No).

(14) 3) Evaluation of Damage during Detachment

(15) Damage during detachment was evaluated by optically observing the fusion bonded part. When a hole was formed at the detached part by damage, it was evaluated that damage occurred during the detachment (expressed as Yes), and when there was no hole, it was evaluated that no damage occurred during the detachment (expressed as No).

(16) 4) Evaluation of Damage at Combined Part (Seam) of Cushion

(17) Damage at the combined part (seam) of the cushion was evaluated by optically observing the combined part (seam) after the airbag was inflated. When the weave structure of the combined part (seam) was split or yarns in the weave structure were torn, it was evaluated that the damage occurred at the combined part (seam) of the cushion (expressed as Yes), and when there was no change in the weave structure from before the inflation, it was evaluated that no damage occurred at the combined part of the cushion (expressed as No).

(18) TABLE-US-00001 TABLE 1 Comparative Comparative Example 1 Example 2 Example 3 Example 4 Example 1 Example 2 Kind of yarn Nylon Nylon PET PET Nylon PET Warp fineness 420 420 420 420 420 500 (de) Weft fineness 420 420 420 420 420 500 (de) Warp density 57 57 57 57 57 57 (th/inch) Weft density 49 49 49 49 49 49 (th/inch) Coated amount 75 75 75 75 75 75 (gsm) Ultrasonic Pressure 50 50 50 50 fusion (psi) bonding Delay 0.5 0.5 0.5 0.5 condition (sec) Hold 0.5 0.5 0.5 0.5 (sec) Time 0.75 1 0.5 1 (sec) Bonding 26.29 24.07 10.38 13.12 strength (kgf) Internal Max 59.6 56.6 64.8 64.7 56.6 66.7 Pressure (kPa) (N.sub.2 After 6 52.5 44.7 49.0 47.7 38.6 32.5 gas) sec (kPa) Fusion bonding Yes Yes Yes Yes Damage during No No No No detachment Damage at seam No No No No Yes Yes of cushion (Inflator)

(19) As shown in Table 1, in the airbags of Examples 1 to 4 according to the present invention, the ultrasonic fusion bonded part was effectively formed near the combined part that is easy to be damaged when the airbag is inflated by an inflator, and the fabrics were not damaged by the detachment of the fusion bonded part when the airbag was inflated. Furthermore, it is recognizable that the airbag of the present invention has excellent characteristics in that the combined part thereof is difficult to damage and thus the internal pressure of the cushion can be maintained for a long time, because the fusion bonded part protects the combined part, namely, the inflating air collides with the fusion bonded part before it collides with the combined part and the shock provided to the combined part is reduced when the airbag is inflated.

(20) On the other hand, it was recognized that the airbags of Comparative Examples 1 and 2 to which the ultrasonic fusion bonding was not applied according to the existing method showed damage at the combined part when the airbags were inflated by an inflator. Therefore, there may be a problem in that the airbags cannot show sufficient internal pressure maintenance performance and airbag inflating performance to protect passengers safely from the accidents such as a car rollover.