AIRBAG CUSHION AND METHOD FOR PREPARING THE SAME

Abstract

The present application relates to an airbag cushion comprising the reinforcing fabric and a method for preparing the same. According to the present application, adequate levels of tenacity, elongation, dimensional stability, impact resistance and the like required for an airbag cushion and its reinforcing fabric are simultaneously met.

Claims

1. An airbag cushion comprising a fiber substrate; and a reinforcing fabric attached to at least a portion of the surface of the fiber substrate and containing polyester yarn as a warp or weft component, wherein the polyester yarn has a tenacity of 8.0 g/d or more, and an elongation at specific load measured at a load of 4.5 g/d of 3.0 to 6.0%, and wherein the reinforcing fabric has a finished fabric construction of at least 24 yarns per inch in the warp direction or weft direction.

2. The airbag cushion according to claim 1, wherein the polyester yarn has a dry heat shrinkage of 10% or less.

3. The airbag cushion according to claim 1, wherein the polyester yarn satisfies a dimension stability index of 10 or less as determined by the following Equation 1:
Dimension stability index=Elongation at specific load of yarn+Dry heat shrinkage of yarn  [Equation 1]

4. The airbag cushion according to claim 1, wherein the polyester yarn has an initial modulus in the range of 100 to 150 g/d.

5. The airbag cushion according to claim 1, wherein the reinforcing fabric includes the polyester yarn as warp and weft components.

6. The airbag cushion according to claim 1, wherein the reinforcing fabric has a finished fabric construction of at least 24 yarns per inch in each of the warp direction and the weft direction.

7. The airbag cushion according to claim 1, wherein the polyester yarn has a total fineness of 420 denier or more.

8. The airbag cushion according to claim 1, wherein the polyester is polyethylene terephthalate.

9. The airbag cushion according to claim 1, comprising one layer of the reinforcing fabric.

10. The airbag cushion according to claim 1, wherein the fiber substrate includes one or more fibers selected from the group consisting of a nylon fiber, a polyester fiber, a polyolefin fiber, and an aramid fiber.

11. The airbag cushion according to claim 10, wherein the fiber substrate includes a fabric or a non-woven fabric.

12. A method for preparing an airbag cushion, the method comprising the steps of: preparing a fabric having a loom state weave construction of 20 yarns or more in the warp direction and the weft direction using a polyester yarn having a tenacity of 8.0 g/d or more, and an elongation at specific load measured at a load of 4.5 g/d of 3.0 to 6.0%; heat-treating the fabric at a temperature of 150° C. or more to produce a reinforcing fabric having a finished fabric construction of 24 or more in the warp or weft direction; and attaching the reinforcing fabric onto at least a portion of a fiber substrate surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG. 1 is a photograph taken from part of the device for the impact puncture resistance measurements described in Experimental Examples below.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0066] Hereinafter, the action and effect of the invention will be described in more detail with reference to specific examples of the invention.

[0067] However, these examples are presented for illustrative purposes only, and the scope of the invention is not limited thereto in any sense.

[0068] EXAMPLE AND COMPARATIVE EXAMPLE

Example 1

[0069] A polyester yarn (PET) having a fineness of 1,000 denier (250 filaments each having a fineness of about 4 denier) was used as the yarn used for the reinforcing fabric. Specifically, a polyester yarn satisfying a tenacity of 9.0 g/d, a modulus characteristic of an elongation at specific load of 5.0% at 4.5 g/d, and a dry heat shrinkage of 4.5% was used for weaving the fabric for reinforcing fabric. These yarns were prepared according to the method previously described (specifically, prepared through the process in which five godet rollers were used during drawing, the speed of the first godet roller was within the range of 2,500 to 3,500 mpm, and the draw ratio was adjusted to a draw ratio of about 2.00 to 2.20).

[0070] The reinforcing fabric was woven so as to have a loom state weave construction in the warp and weft directions of 20×20 (warp×weft) yarns per unit inch. Then, the woven fabric was continuously passed through a scouring tank maintained at a temperature of about 85° C. to remove impurities from the fabric. After that, for post-processing heat treatment for shrinkage expression and heat setting, the fabric from which impurities were removed was heat-treated at 180° C. for about 1 minute in such a way that it passed through a hot-air tenter. The resulting reinforcing fabric has a final finished fabric construction of 24.2×24.0 (warp×weft) yarns per unit inch in the warp and weft directions, respectively.

[0071] The characteristics of the yarns used and the density characteristics of the fabrics are shown in Table 1 below.

Example 2

[0072] Through the same process as in Example 1, the yarn having the same characteristics as in Example 1 was used for weaving the reinforcing fabric, except that the tenacity and initial elastic modulus of the yarn are different as shown in Table 1.

[0073] In addition, the final finished fabric construction of the prepared reinforcing fabric was 24.5×24.0 (warp×weft) yarns per unit inch in the warp and weft directions, respectively. Other weaving processes and conditions were the same as those described in Example 1.

Example 3

[0074] The same polyester yarn as in Example 1 was used for weaving the fabric. However, in the weaving of the reinforcing fabric, the textile fabric was woven so as to have the loom state weave construction in the warp and weft directions of 24.0×24.0 yarns (warp×weft) per unit inch, and subjected to shrinkage expression and heat setting. The fabric was prepared so that the final finished fabric construction of the resulting textile fabric was 26.2×26.7 (warp×weft) yarns per unit inch in the warp and weft directions, respectively. Other weaving processes and conditions were the same as those described in Example 1.

Comparative Example 1

[0075] The yarn was prepared by varying the spinning speed and the draw ratio range applied when preparing the yarn of Example 1 (specifically, the spinning speed was less than 2500 mpm and the draw ratio was about 1.8). The prepared polyester yarn showed a tenacity of 7.0 g/d, a modulus characteristic of the elongation at specific load of 7.0% at 4.5 g/d, a dry heat shrinkage of 2.0% and an initial elastic modulus of HO g/d, which was used for weaving a reinforcing fabric.

[0076] The resulting reinforcing fabric had a final finished fabric construction of 24.3×24.2 (warp×weft) yarns per unit inch in warp and well directions, respectively. Other conditions regarding the production and weaving process of the yarn are the same as those described in Example 1.

Comparative Example 2

[0077] As shown in Table 1, a polyester yarn having an initial elastic modulus of the yarn different from that of Example 1 was used for weaving the fabric.

[0078] In the weaving of a reinforcing fabric, the textile fabric was woven so as to have a loom state weave construction in the warp and weft directions of 18×18 (warp×weft) yarns per unit inch, and subjected to shrinkage expression and heat setting. The fabric was prepared so that the final finished fabric construction of the resulting textile fabric was 20.3×20.1 (warp×weft) yarns per unit inch in the warp and weft directions, respectively. Other conditions related to the production and weaving process of the yarn are the same as those described in Comparative Example 1.

Comparative Example 3

[0079] As shown in Table 1, a polyester yarn having the same yarn characteristics as in Comparative Example 2 was used for weaving the fabric.

[0080] In the case of weaving, a fabric was prepared through the same conditions and process as in Example 1, except that the post-finishing heat treatment temperature for the fabric that has undergone the removal of impurities was heat-treated at 130° C.

[0081] Evaluation of the Fabric

[0082] (1) Tensile Strength and Elongation

[0083] This is for measuring tensile strength in warp and weft directions, and specimens with a size of 60 mm were prepared from the reinforcing fabrics prepared in Examples and Comparative Examples,

[0084] Specifically, a specimen with a size of 60 mm×320 mm was taken according to the ISO 13934-1 cut & strip test standard, and the threads on both sides of the specimen were peeled off to make a specimen with a total width of 5.0 mm. Then, the strength and elongation at the time when the sample fracture occurred were measured while pulling the specimen at a speed of 200 mm/min crosshead speed using a universal testing machine (UTM) according to the method specified in ISO 13934-1.

[0085] (2) Stiffness or King Stiffness

[0086] This is for measuring the stiffness in warp and weft directions, specimens with a size of 100 mm×100 mm were taken from the reinforcing fabrics prepared in Examples and Comparative Examples, and were folded in half. In accordance with ASTM D4032, the folded specimen was mounted onto a circular bend stiffness measuring device, and then the plunger has push down at a speed of 2,000 mm/min, and the load applied at that time was measured using a digital gauge.

[0087] For reference, if the stiffness was lower than 6N as in Comparative Example, the puncture resistance against sharp objects (such as glass or protruding objects) were not good. In addition, when the king stiffness was excessively high, such as exceeding the numerical values of Examples listed in Table 2 below, the fabric may be too stiff, reducing the foldability and tear strength of the airbag cushion.

[0088] (3) Tear Strength

[0089] This is for measuring the tear strength in warp and weft directions, and specimens with a size of 150 mm×200 mm were prepared from the reinforcing fabrics prepared in Examples and Comparative Examples. And, the tear strength of the specimen was measured by the tongue method specified in ISO 13937-2 using a universal testing machine (UTM). Specifically, while the specimen for measuring the tear strength in the warp direction was pulled in the warp direction, and the specimen for measuring the tear strength in the weft direction was pulled in the weft direction at a rate of 100 mm/min, the tear strength was measured.

[0090] (4) Dimension Stability

[0091] This is for measuring the dimensional stability of the textile fabric at high temperature, and the dimensional stability was measured for a specimen with a size of 300 mm×300 mm. As the specimens, the reinforcing fabrics prepared in Examples and Comparative Examples were used. The specimen was marked horizontally and vertically with 250 mm×250 mm, and then heat treated at high temperature, and then the length strain was measured. Specifically, the specimen was left in a high temperature chamber at 105° C. for 60 minutes, and the strain was calculated using the following Equation.

Equation:{(X.sub.0−X.sub.1)/X.sub.0}×100

[0092] (wherein, in Equation, X.sub.0 is the initial length in the horizontal and vertical directions before storing the specimen at 105° C., and X.sub.1 is the deformation length in the transverse and longitudinal directions after the specimen is stored at 105° C. for 60 days.)

[0093] (5) Puncture Resistance

[0094] The puncture resistance of the textile fabric was measured according to ASTM-F1342. Specifically, the reinforcing fabric specimens prepared in Examples and Comparative Examples were mounted on a dedicated sample holder, and then penetrated the textile fabric with a probe having a tip radius of 1.0 mm using a universal testing machine (UTM), and the maximum force was measured.

[0095] (6) Impact Puncture Resistance

[0096] The instantaneous impact puncture resistance of the fabric specimen prepared in Examples and Comparative Examples were measured according to its own internal test specification. Specifically, a specimen having a size of 300 mm×300 mm was obtained, and the specimen was mounted onto the sample holder of the self-made device as shown in FIG. 1. The test device of FIG. 1 was designed to apply a pendulum-type impact, and a cantilever equipped with a piece of glass probe was naturally dropped from a 180 degree horizontal position to apply an instantaneous impact to the fabric, and then the length of the section torn by the probe was measured.

TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Example 1 Example 2 Example 3 Example 1 Example 2 Example 3 Yarn liner 1,000 1,000 1,000 1,000 1,000 1,000 fineness Yarn 9.0 10.0 9.0 7.0 9.0 9.0 tenacity Yarn 5.0 5.0 5.0 7.0 5.0 5.0 EASL Yarn dry 4.5 4.5 4.5 2.0 4.5 4.5 heat shrinkage Dimensional 9.5 9.5 9.5 9.0 9.5 9.5 stability index Initial 125 140 125 110 110 110 elastic modulus of yarn Loom state 20 × 20 20 × 20 24 × 24 20 × 20 18 × 18 20 × 20 weave construction Finished 24.2 × 24.0 24.5 × 24.0 26.2 × 26.7 24.3 × 24.2 20.3 × 20.1 23.3 × 22.2 fabric construction Unit * Yarn total fineness (liner density): Denier * (Yarn Tenacity): g/d * Elongation at specific load (EASL, at 4.5 g/d): % *Yarn dry heat shrinkage: % *Dimensional stability index (ES rate): Elongation at specific load (%) + Yarn dry heatshrinkage (%) *Yarn initial modulus): g/d *Loom state weave construction (warp × weft): th/inch *Finished fabric construction (warp × weft): th/inch

TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Example Example Example Example 1 Example 2 Example 3 1 2 3 Tensile strength 4,056 4,234 4,317 3,651 3,521 3,720 (warp) Tensile strength 3958 4252 4,452 3,568 3,662 3,651 (weft) Elongation (warp) 20.7 22.4 22.2 17.6 17.2 17.3 Elongation (weft) 19.3 23.2 20.5 19.6 18.3 16.6 King stiffness 8.8 9.5 10.5 5.5 4.3 5.2 (warp) King stiffness 7.8 8.4 11.8 5.2 4.8 4.3 (weft) Tear strength 414 472 492 312 325 354 (warp) Tear strength 374 453 487 304 312 320 (weft) Dimensional 0.1 0.2 0.1 0.4 0.4 1.2 stability (warp) Dimensional 0.1 0.3 0.1 0.3 0.2 1.5 stability (weft) Puncture 12.6 15.2 19.7 5.3 3.4 4.3 resistance Impact puncture 1.2 1.1 1.5 6.7 10.3 6.5 resistance Unit *Tensile strength: N/5 cm * Elongation: % *Tear strength: N *King stiffness: N *Dimensional stability: % * Puncture resistance: N * Impact puncture resistance (torn length): mm