KR20130007267A - Aramid fabrics and airbag for a car by using the same - Google Patents

Abstract

PURPOSE: A fabric and an air bag with the same for an automobile are provided to remarkably lower stiffness using an aramid fiber, to ensure excellent mechanical property, and to minimize shock applied to the automobile and passengers. CONSTITUTION: An aramid fabric for an air bag(124) has an aramid fiber. The fineness of warp and weft is each 200-1000 denier. The density of the warp and weft is each 20-55th/inch. The stiffness of the aramid fabric is 1.5 kgf or less according to American Society for Testing Materials(ASTM) D4032 method. The tensile strength of the aramid fabric is 150 kgf/10mm or greater according to ASTM D5034 method. An air bag for an automobile contains the aramid fabric.

Description

Aramid fabric and vehicle air bag including the same {ARAMID FABRICS AND AIRBAG FOR A CAR BY USING THE SAME}

The present invention relates to an airbag fabric and a vehicle airbag including the same. More particularly, the present invention relates to an aramid fabric having excellent mechanical properties such as toughness and energy absorption performance, together with excellent storage properties, flexibility, and shape stability, and a vehicle airbag including the same. will be.

Generally, an air bag detects a collision impact applied to a vehicle at the time of a frontal collision at a speed of about 40 km / h or more at a speed of about 40 km / h by the impact sensor, And inflates the inflator to supply air to the inflator, thereby protecting the driver and the passenger. The structure of a typical air bag system is the same as that shown in Fig.

1, a general airbag system includes an inflator 121 that generates gas by ignition of a priming tube 122, and an airbag 124 that inflates and deploys toward the driver of the driver's seat by the generated gas An airbag module 100 mounted on the steering wheel 101, an impact sensor 130 for generating an impact signal in the event of an impact, and an electronic control module (not shown) for igniting the primer 122 of the inflator 121 And an electronic control module 110. When the vehicle collides head-on, the airbag system configured as described above senses an impact in the impact sensor 130 and transmits a signal to the electronic control module 110. At this time, the electronic control module 110 recognizing this ignites the primer 122 to burn the gas generating agent in the inflator 121. The gas generating agent thus combusted expands the air bag 124 through rapid gas generation. The inflated and deployed airbag 124 partially absorbs the impact load due to the collision while contacting the front surface of the driver and collides with the inflated airbag 124 as the driver's head and chest move forward due to inertia The gas of the airbag 124 is rapidly discharged to the exhaust hole formed in the airbag 124, so that the front surface of the driver is buffered. Therefore, by effectively buffering the impact force transmitted to the driver in the frontal collision, it is possible to reduce the secondary injury.

As described above, after the airbag used in the vehicle is manufactured in a predetermined form, the inflator 121 operates by being mounted on the handle of the vehicle, the side glass window or the side structure of the vehicle in a folded state to minimize the volume thereof, and maintaining the folded state. Allow the airbag to inflate and deploy.

Therefore, in order to effectively maintain the folding and packageability of the airbag when installing the vehicle, to prevent damage and rupture of the airbag itself, to exhibit excellent airbag cushion deployment performance, and to minimize the impact on passengers, the airbag fabric has excellent mechanical properties. In addition, foldability and flexibility to reduce the impact on passengers is very important. However, airbag fabrics that maintain excellent air blocking effect and flexibility at the same time for the safety of the passengers, sufficiently endure the impact of airbags and can be effectively mounted in a vehicle have not been proposed.

In particular, the airbag is a device that effectively buffers the impact force transmitted to the driver or other occupants in the past, but is mounted on the outside of the vehicle to cushion the impact on the impact applied to the pedestrian or the vehicle itself in recent years. Airbags are increasing. As described above, in the case of a bumper-type airbag, which is mounted on an external bumper of the vehicle and serves to cushion the impact force against the impact on the vehicle body, the airbag is generally mounted inside the vehicle to cushion the impact force of the occupant. Because of the high impact force required to absorb, the amount of impact on the airbag itself is also very high. In this case, the airbag does not endure this high impact force, there is a limit that does not buffer the impact force and the fabric of the airbag is ruptured to perform its role normally, the development of technology of the fabric that can withstand such high impact force is urgently required to be.

Therefore, even when applied as a bumper type airbag, the fabric for the airbag that can withstand the high impact force of the outside, but also has excellent shape stability and air blocking effect, excellent folding property and excellent mechanical properties even under the harsh conditions of high temperature and high humidity, which can be folded compactly. Research on development is needed.

The present invention exhibits optimized flexibility and mechanical properties as a fabric for airbags, and thus can produce an airbag cushion that exhibits improved folding and deployment performance while minimizing promotion and impact on the vehicle even when mounted outside the vehicle. To provide aramid fabric.

The present invention also provides a vehicle airbag including the aramid fabric.

The present invention provides aramid fabric containing aramid fibers, the cover factor of 1,000 to 2,000 as shown in the following formula (1).

[Equation 1]

The present invention also provides a vehicle airbag including the aramid fabric.

Hereinafter, aramid fabric and a vehicle airbag including the same according to a specific embodiment of the present invention will be described in detail. It will be apparent to those skilled in the art, however, that this is not intended to limit the scope of the invention, which is set forth as an example of the invention, and that various modifications may be made to the embodiments within the scope of the invention.

In addition, throughout this specification, "comprising" or "containing ", unless specifically stated, refers to including any and all components (or components) Can not be interpreted as excluding.

The present invention by applying the aramid-based yarn to manufacture the fabric for the air bag, it is possible to secure excellent performance in the bumper-type airbag that can be mounted on the outside of the vehicle to withstand high impact force. In addition, the present invention can significantly secure the stiffness of the fabric for the airbag, it is possible to ensure excellent folding performance of the airbag cushion.

In general, airbag cushions that are mounted inside a vehicle to protect occupant safety have been manufactured mainly using nylon-based yarns. Even when the cover factor is manufactured at a high level of about 2,058 by applying the nylon-based yarn, the tensile strength of the fabric is only 128 kgf / 10mm, and the airbag cushion using the fabric has its impact force when mounted outside the vehicle. There is a limit to endure it. On the other hand, in order to improve the strength of the fabric, the application of nylon-based yarn, etc. to increase the fineness or density of the yarn may cause the problem of weaving, and the stiffness of the fabric is too high, the folding is significantly reduced, the vehicle There is a problem that can not accommodate the cushion in the minimized range of.

As a result of the experiments of the present inventors, by using the aramid fibers to make the cover factor (Cover Factor) of the fabric to a predetermined range, while controlling the stiffness of the fabric to the optimal range, the shock absorption performance for the vehicle and promotion is maximized It has been found that excellent mechanical properties and air barrier effect can be obtained.

According to one embodiment of the present invention, an aramid fabric is provided. Such aramid fabric includes aramid fibers, the cover factor (CF) as shown in the following formula (1) is 1,000 to 2,000, preferably 1,100 to 1,900, more preferably 1,150 to 1,850, more preferably 1,200 To 1,780.

[Equation 1]

Here, when the cover factor of the fabric is less than 1,000, the focusing force of the fabric is weak, so that the tensile strength and the bark strength of the fabric are reduced, and thus the airbag cushion cannot exhibit sufficient shock absorption performance, and air is easily discharged to the outside when the air is inflated. May occur. In addition, when the cover factor of the fabric is more than 2,000, the airbag cushion storage and folding properties of the airbag can be significantly reduced.

The fabric for the airbag of the present invention is supplied by an inflator having a larger capacity according to the increased cushion volume even when manufactured as an airbag cushion mounted on the outside of the vehicle, in particular by optimizing the cover factor using aramid fibers as described above. Strength and heat resistance sufficient to withstand the high pressure and high temperature inflator gas can be secured.

At this time, the warp density and the weft density of the aramid fabric, that is, the weaving density in the warp direction and the weft direction are respectively 20 to 55 th / inch, preferably 21 to 54 th / inch, more preferably 22 to 53 th can be / inch. Inclined density and weft density of the aramid fabric may be 20 th / inch or more in terms of securing the excellent mechanical properties of the airbag fabric, respectively 55 th / in terms of improving the folding properties of the fabric and lowering the tear strength, etc. It can be less than an inch.

In addition, the inclined fineness and weft fineness used in the aramid fabric, that is, the total fineness of the aramid fibers used in the inclined direction and the weft direction are respectively 200 to 1,000 denier, preferably 250 to 950 denier, more preferably 300 to It can be 900 denier. Slant fineness and weft fineness in the aramid fabric may be selected in the range as described above in terms of ensuring excellent ductility characteristics with excellent mechanical properties by optimizing the cover factor of the fabric. The denier is a unit representing the thickness of a yarn or fiber, and is 1 denier when a length of 9,000 m is 1 g.

The airbag fabric of the present invention can be used to secure excellent mechanical properties and heat resistance using aramid fibers, the aramid fibers are characterized by a molecular structure in which the phenyl ring is connected to all the main chain except the amide group. In addition, aramid has a meta-type (m-) and a para-type (p-) containing a repeating unit of the formula (1) according to the linking state of the phenyl ring, poly ( p-phenylene terephthalamide) (poly (phenylene terephthalate)) can be used. In particular, in the case of para-type (p-) aramid fibers, the phenyl rings are laminated in a plate shape with each other, the crystallinity is very high, the heat resistance is excellent, due to the high mechanical strength of the high strength, high elastic modulus, with a low shrinkage rate, etc. It is still more preferable as a material for airbag cushion manufacturing.

The tensile strength of the aramid fibers may be 15 g / d or more or 15 to 45 g / d, preferably 18 g / d or more, more preferably 20 g / d or more. In addition, the elongation at break of the aramid fibers may be 3% or more or 3% to 35%, preferably 4% or more, more preferably 5% or more.

The aramid fabric of the present invention has a stiffness of 1.5 kgf or less or 0.2 to 1.5 kgf, preferably 1.45 kgf or less or 0.3 kgf to 1.45 kgf, or more preferably 1.4 kgf or less, according to the American Society for Testing and Materials Standard ASTM D 4032 method. 0.4 kgf to 1.4 kgf. When the stiffness of the fabric exceeds 1.5 kgf, the foldability of the fabric is so low that the folding property of the airbag cushion may be significantly reduced. However, if the stiffness of the fabric is too low, it may not be able to provide sufficient protection and support during airbag expansion and deployment, and the stiffness of the fabric is 0.2 kgf because the shape retention performance may be reduced even when the vehicle is mounted. It can be abnormal.

In addition, the tensile strength of the aramid fabric is 150 kgf / 10mm or more or 150 to 500 kgf / 10mm, preferably 160 kgf / 10mm or more or 160 to 480 kgf /, as measured by the American Society for Testing and Materials Standard ASTM D 5034 method. 10 mm, more preferably 170 kgf / 10 mm or more, or 170 to 400 kgf / 10 mm. If the tensile strength of the fabric is less than 150 kgf / 10mm may be mounted on the outside of the vehicle may not exhibit sufficient shock absorption performance. However, the tensile strength of the fabric may be greater than or equal to 500 kgf / 10mm in terms of improving the folding property of the airbag cushion by optimizing the stiffness and thickness of the fabric.

In addition, the aramid fabric of the present invention may be 0.10 mm to 0.45 mm, preferably 0.12 mm to 0.43 mm, more preferably 0.15 mm to 0,40 mm measured after the ISO 2286-3 method have. When the thickness of the fabric exceeds 0.45 mm, the folding property of the airbag cushion may be significantly reduced. If the thickness of the fabric is less than 0.12 mm, the shape retention performance may be reduced when the vehicle is mounted after folding the airbag cushion. Can be.

On the other hand, the fabric for the airbag of the present invention may include a sewing unit for bonding the fabric in the process of manufacturing the airbag cushion form. Since the sewing part is mainly the air is discharged during the deployment of the air bag, it is possible to optimize the physical properties such as the sewing strength and elongation of the sewing part. In particular, in order to exhibit excellent inflation performance and deployment performance during airbag deployment due to rapid gas generation, it is desirable to effectively maintain the bonding performance for each part of the airbag cushion.

In this aspect, the fabric for the airbag of the present invention can optimize the sewing material, fineness, sewing method, etc., to improve the bark strength and elongation of the sewing portion and ensure excellent pressure resistance performance.

In the airbag fabric, the sewing part is bonded using a sewing thread including one or more selected from the group consisting of nylon yarn, polyester yarn, polyolefin yarn, and aramid yarn, and nylon as a sewing thread in terms of heat resistance and shrinkage. It is preferable to use yarns such as 66, nylon 46, kevlar (aramid yarn), and most preferably nylon 66 can be used.

The thickness of the sewing thread, that is, the total fineness may be used having a 210 to 1260 denier, preferably 840 to 1260 denier, the sewing thread thickness is preferably 210 denier or more in terms of strength, the sewing thread thickness in terms of resistance (elasticity) Is preferably 1260 denier or less.

The sewing thread can be used in the tensile strength of 58 N or more, preferably 58 N to 110 N measured by the method of the American Society for Testing and Materials ASTM D 204-97, the preferred range is 89 N to 1,260 denier In the case of 110 N, 840 denier, it can be used from 58 N to 80 N. If the tensile strength of the sewing thread is less than the above range, the strength of the sewing portion is too weak, and the sewing portion may be torn off during manufacture or deployment of the airbag. If the tensile strength is too large, the strength of the sewing portion is too strong, so that the airbag is deployed. The development time point or shape of may be abnormally developed.

In addition, the sewing unit in the airbag cushion of the present invention can be used to select an effective sewing method according to the use of each part, it is possible to apply one or more sewing methods of single lock, double lock, single chain, double chain.

The sewing unit may be applied by adjusting the number of stitches in the optimum range according to the use of each part or according to the sewing method, preferably 20 to 80 ea / 100mm, more preferably 25 to 75 ea / 100mm, more preferably The sewing can be bonded while controlling the number of stitches to 30 to 70 ea / 10mm. At this time, if the number of stitches is less than 20 ea / 100mm, the strength of the sewing part is too weak, so that the sewing part may be torn during manufacture or development, and if the number of stitches exceeds 80 ea / 100mm, the strength of the sewing part is so strong that the fabric is When the airbag is damaged or the airbag is deployed, the time or shape of the airbag may be abnormally deployed.

In the airbag fabric of the present invention, the sewing portion is measured by the method of the American Society for Testing and Materials Standard ASTM D 1683, the bark strength of 100 kgf / 20mm or more or 100 to 400 kgf / 20mm, preferably 130 kgf / 20mm or 130 to 400 kgf / 20 mm, most preferably 150 kgf / 20 mm or more, or 150 to 350 kgf / 20 mm. The bark strength of the fabric may be 100 kgf / 20mm or more in terms of securing sufficient mechanical properties to withstand the inflator gas at high temperature and high pressure when the airbag is inflated. It is desirable to maintain the level at a high level.

In addition, the aramid fabric may preferably further comprise a rubber component coating layer coated or laminated on the surface. The rubber component may include at least one selected from the group consisting of powder type silicone, liquid type silicone, polyurethane, chloroprene, neoprene rubber, and emulsion type silicone resin. Is not limited only to the above-mentioned materials. However, liquid silicone coating is preferable in terms of environmentally friendly and mechanical properties.

The coating amount per unit area of the rubber component coating layer may be used to 20 to 200 g / m ² , preferably 20 to 100 g / m ² . In particular, in the case of a fabric for a side curtain airbag of OPW (One Piece Woven) type, the coating amount is preferably 30 g / m ² to 95 g / m ² , and in the case of plain weave for airbag, m ² to 50 g / m ² is preferable.

The aramid fabric of the present invention is a static air permeability according to the American Society for Testing and Materials Standard ASTM D 737 method is 10.0 cfm or less or 0.3 to 10.0 cfm, preferably 8.0 cfm or less when ΔP is 125 pa for uncoated fabric or 0.3 to 8.0 cfm, more preferably 5.0 cfm or less, or 0.3 to 5.0 cfm, and when ΔP is 500 pa, 14 cfm or less or 4 to 14 cfm, preferably 12 cfm or less or 4 to 12 cfm. Can be. In addition, the dynamic air permeability according to the American Society for Testing and Materials Standard ASTM D 6476 method is 1,700 mm / s or less, preferably 1,600 mm / s or 200 to 1,600 mm / s, more preferably 1,400 mm / s or 400 To 1,400 mm / s. In this case, the static air permeability refers to the amount of air that penetrates into the fabric when a certain pressure is applied to the fabric for the air bag, and the smaller the denier per filament of the yarn and the higher the density of the fabric, the lower the value. In addition, the dynamic air permeability refers to the degree of air permeation to the fabric when the average instantaneous differential pressure of 30 to 70 kPa is applied. May have

In particular, the air permeability of the arimid fabric can be significantly lowered by including a rubber coating layer on the fabric, it is possible to ensure the air permeability of the value close to 0 cfm. However, when the rubber component coating is performed as described above, the airbag coating fabric of the present invention has a static air permeability of 0.1 cfm or less from 0 to 0.1 cfm when △ P is 125 pa according to the American Society for Testing and Materials Standard ASTM D 737 method. Preferably, it may be 0.05 cfm or less or 0 to 0.05 cfm, and when ΔP is 500 pa, 0.3 cfm or less or 0 to 0.3 cfm, preferably 0.1 cfm or less or 0 to 0.1 cfm.

Here, the aramid fabric of the present invention for the non-coated fabric and the coated fabric, when the upper limit of the static air permeability range, respectively, or the upper limit of the dynamic air permeability range exceeds the side to maintain the airtightness of the fabric for the air bag May be undesirable.

On the other hand, according to another embodiment of the invention, there is provided a method for producing aramid fabric as described above. The manufacturing method of the fabric is a step of weaving the dough for the air bag using aramid fibers so that the cover factor as shown in the following formula 1 to 1,000 to 2,000, refining the woven fabric for the air bag, and the refined fabric It may include the step of opening and closing.

[Equation 1]

In the present invention, after the aramid fibers are manufactured into an airbag cushion fabric through a conventional weaving method, a refining and heat-setting process in a range that allows the cover factor to be optimized, and if necessary, the process may be processed through an additional process such as silicone rubber coating. It may be. The airbag cushion fabric coated in this way is manufactured into a predetermined type airbag cushion through a cutting and sewing process as described below. At this time, the airbag cushion is not limited to a particular form and can be manufactured in a general form, for example, both plain weave type and woven type of OPW (One Piece Woven) type is preferable.

In particular, the fabric for airbags of the present invention can be produced through beaming, weaving, refining, and heat setting processes using aramid fibers as weft and warp yarns. The fabric may be manufactured using a conventional weaving machine, and is not limited to the use of any specific loom. However, plain weave fabrics may be manufactured using a Rapier Loom, an Air Jet Loom, or a Water Jet Loom, and the OPW type fabric may be manufactured using Jacquard looms Loom. ≪ / RTI >

On the other hand, according to another embodiment of the invention, there is provided a vehicle airbag comprising the aramid fabric described above. In addition, there is provided an airbag system comprising the above airbag, which may be provided with conventional devices well known to those skilled in the art.

The airbag may be classified into a frontal airbag, a side curtain airbag, and a bumper type airbag outside the vehicle. The frontal airbag includes a driver's seat, a passenger seat, a side protection, a knee protection, ankle protection, an pedestrian protection airbag, and the side curtain type airbag protects passengers in a vehicle side collision or rollover accident, and is mounted outside the vehicle. Bumper airbags of the type serve to cushion shocks to pedestrians or to the vehicle itself. Accordingly, the airbag of the present invention includes both a frontal airbag, a side curtain airbag, a bumper airbag and the like.

In particular, the aramid fabric of the present invention can be effectively used for exterior type bumper airbags and the like mounted on the vehicle exterior bumper by securing high mechanical properties and excellent flexibility at the same time. An example of such a bumper airbag is as shown in FIG. As shown in FIG. 2, the bumper airbag device 201 includes an airbag 203 received in a contracted state in a front bumper 202 of the vehicle 200, and an inflator connected to the airbag 203. and an inflator 204. When the airbag device 201 is operated, the inflator 204 generates a high temperature and high pressure gas, so that the air bag 203 to which the high temperature and high pressure gas is supplied is located in front of the front bumper 202. To be deployed. Thereby, the impact from the vehicle which collides with the front bumper 202, and the impact of a pedestrian can be alleviated. In addition, in the above-described example, although the airbag device including the aramid fabric of the present invention is accommodated in the front bumper, it can also be used in the form of mounting on the rear bumper of the vehicle, if necessary.

In the present invention, matters other than those described above can be added or subtracted as required, and therefore, the present invention is not particularly limited thereto.

According to the present invention, by weaving the fabric in a specific cover factor range using aramid fibers, there is provided an airbag fabric and a vehicle airbag including the same having excellent flexibility and folding properties with excellent mechanical properties.

This aramid fabric can not only achieve excellent morphological stability, mechanical properties, and air barrier effect, but at the same time ensure excellent folding and flexibility, significantly improving the storage performance when the vehicle is mounted, and at the same time, the impact on the vehicle and passengers. Minimized to protect passengers.

In particular, the aramid fabric according to the present invention can be very preferably used for the manufacture of bumper type airbag cushion that can be mounted on the outside of the vehicle to cushion the high impact force.

1 shows a general airbag system.
FIG. 2 is a diagram illustrating a vehicle having an exterior type bumper airbag mounted outside the vehicle. FIG.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Example  1 to 8

The process conditions as shown in Table 1 below, using aramid fibers to prepare a fabric for the air bag.

First, the fabric dough for airbags was woven through a rapier weaving machine using aramid fibers. The fabric dough was subjected to two consecutive refining and heat treatment processes to prepare an airbag fabric. The non-coating fabric thus prepared is directly used as a fabric fabric for airbag cushions (Examples 2, 3, 5, 6, and 8), or the liquid silicone rubber (Non-Coating) is applied to the non-coating fabric. Using a silicone coating agent based on the LSR resin, a silicone coating fabric coated by a knife over ro1l coating method was used as the fabric fabric for the airbag cushion (Examples 1, 4, 7). ).

In addition, the fabric was cut using a laser cutting machine, and sewing the fabric under sewing conditions as shown in Table 1 below to prepare an airbag cushion.

At this time, the yarn type and woven form of the fabric for the airbag, the coating component and coating amount, the type of sewing thread and the sewing method is as shown in Table 1 below. Here, the cover factor (CF) of the far end is a value calculated according to Formula 1 below. The rest of the conditions were in accordance with conventional conditions for the manufacture of airbag cushions.

[Equation 1]

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Yarn Type Ara
mid Ara
mid Ara
mid Ara
mid Ara
mid Ara
mid Ara
mid Ara
mid Inclination fineness (de) 840 840 840 600 600 600 400 400 Wesa island (de) 840 840 840 600 600 600 400 400 Slope density (th / inch) 28 28 32 28 28 35 44 44 Weft Density (th / inch) 28 28 32 28 28 35 44 44 Cover Pattern (CF) 1623 1623 1855 1372 1372 1715 1760 1760 Coating U radish radish U radish radish U radish Coating material silicon - - silicon - - silicon - Coating amount (gsm) 60 - - 40 - - 40 - Type of sewing machine nylon nylon nylon nylon nylon nylon nylon nylon Sewing thread Island (de) 1,260 1,260 1,260 1,260 1,260 1,260 1,260 1,260 Sewing stitch count (th / 100mm) 35 35 35 35 35 35 35 35

Various physical properties of the airbag cushion prepared according to Examples 1 to 8 were measured by the following method, and the measured physical properties are summarized in Table 2 below.

(a) Tensile strength and elongation at break

The specimen was cut from the airbag fabric and fixed to the lower clamp of the tensile strength measuring device according to the American Society for Testing and Materials, ASTM D 5034. The strength and elongation at the time of breaking the airbag fabric specimen were measured while moving the upper clamp upward.

(b) lecture

The ductility of the fabric was measured by the circular bend method using a ductility measuring device according to the American Material Testing Association standard ASTM D 4032. In addition, the cantilever method may be applied as a method of measuring the stiffness, and the stiffness can be measured by measuring the bend length of the fabric using a cantilever measuring device, which is a test bench that is inclined at an angle to give a bend to the fabric.

(c) after

The thickness of the fabric for airbags was measured according to the International Organization for Standardization ISO 2286-3.

(d) air permeability

According to the American Society for Testing and Materials, ASTM D 737, the airbag fabric was allowed to stand at 20 ° C. and 65% RH for at least one day, and then the amount of air passing through a circular section of 38 cm ² was measured at 125 Pa.

(e) Bark strength

The sewing part of the airbag cushion was fixed to the lower clamp of the measuring device according to the ASTM D 1683 method, and the bark strength when the airbag cushion specimen was broken while the upper clamp was moved upward was measured.

division Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Tensile strength (kgf / 10mm) 233 228 262 203 201 218 182 191 Lecture degree (kgf) 1.32 0.79 1.02 1.00 0.85 1.11 1.26 0.87 Thickness (mm) 0.32 0.27 0.29 0.24 0.22 0.23 0.19 0.17 Air permeability (cfm) 0.00 1.71 1.60 0.00 2.88 2.34 0.03 0.81 Bark strength (kgf / 20mm) 215 230 280 232 211 229 191 164

Comparative example  1 to 8

Except for the conditions described in Table 3, according to the same method as in Examples 1 to 8 was prepared for the airbag fabric of Comparative Examples 1 to 8 and the airbag cushion using the same.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Yarn Type nylon nylon Ara
mid Ara
mid Ara
mid Ara
mid nylon nylon Inclination fineness (de) 630 630 400 400 840 840 420 420 Wesa island (de) 630 630 400 400 840 840 420 420 Slope density (th / inch) 41 41 24 24 41 41 46 48 Weft Density (th / inch) 41 41 24 24 41 41 46 48 Cover Pattern (CF) 2058 2058 960 960 2377 2377 1885 1967 Coating U radish U radish U radish U radish Coating material silicon - silicon - silicon - silicon - Coating amount (gsm) 25 - 25 - 25 - 25 - Type of sewing machine nylon nylon nylon nylon nylon nylon nylon nylon Sewing thread Island (de) 1260 1260 1260 1260 1260 1260 1260 1260 Sewing stitch count (th / 100mm) 35 35 35 35 35 35 35 35

For the airbag cushion prepared according to Comparative Examples 1 to 8, various physical properties were measured by the same method as described above, and the measured physical properties are summarized in Table 4 below.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Tensile strength (kgf / 10mm) 128 120 92 90 361 358 90 100 Lecture degree (kgf) 1.31 1.12 0.48 0.35 1.82 1.62 1.0 0.7 Thickness (mm) 0.37 0.35 0.13 0.11 0.48 0.46 0.28 0.30 Air permeability (cfm) 0.00 2.0 5.1 12 0 1.2 0 2.0 Bark strength (kgf / 20mm) 120 113 108 110 250 248 108 104

As shown in Table 2, the fabric for airbags of Examples 1 to 8, which manufactured the cover factor in the optimum range using an aramid yarn, significantly improved the stiffness to 0.79 to 1.32 kgf, and was compactly folded even in the bumper type. As far as possible, it can be seen that there is no problem in the folding property. At the same time, the fabrics according to Examples 1 to 8 exhibited very excellent mechanical properties such as tensile strength of 182 to 262 kgf / 10mm and rod strength of 164 to 280 kgf / 20mm, thereby expressing its performance from the outside of the vehicle. It was confirmed that there was no problem at all.

On the other hand, as shown in Table 4, it was confirmed that the fabric for the airbags of Comparative Examples 1 and 2 using nylon yarn as in the prior art does not meet these characteristics. In particular, it can be seen that the fabrics for airbags of Comparative Examples 1 and 2 are remarkably dropped to 128 kgf / 10 mm and 120 kgf / 10 mm, respectively, and thus have limitations in expressing performance from outside of the vehicle. In addition, the airbag fabrics of Comparative Examples 3 and 4 had a problem that the coating agent leaked to the back side during coating due to a too low cover factor, even though aramid-based yarns were used. It is only 92 kgf / 10mm and 90 kgf / 10mm, bar strength is also significantly dropped to 108 kgf / 20mm and 110 kgf / 20mm, respectively, it can be seen that there is a limit in expressing the performance from the outside of the vehicle. On the contrary, the airbag fabrics of Comparative Examples 5 and 6 have too high Cover Factor, so that the fabric's stiffness is not good as 1.82 kgf and 1.62 kgf, respectively. There was a problem that can not be accommodated in the space of the size. On the other hand, in the case of Comparative Examples 7 and 8, the mechanical properties such as tensile strength and bark strength drop sharply, the air bag itself may be damaged or ruptured when inflating the air bag by the inflator gas of high temperature and high pressure.

Claims (9)

Aramid fabric comprising aramid fibers, the cover factor of 1,000 to 2,000 as shown in the following formula (1).
[Equation 1]

The method of claim 1,
The inclined fineness and weft fineness is aramid fabric of 200 to 1,000 denier respectively. The method of claim 1,
The inclined density and weft density is aramid fabric of 20 to 55 th / inch, respectively. The method of claim 1,
Aramid fabric with a stiffness of 1.5 kgf or less according to ASTM D 4032 method. The method of claim 1,
Aramid fabric having a thickness of 0.10 mm to 0.45 mm measured by the International Organization for Standardization ISO 2286-3. The method of claim 1,
Aramid fabric with a tensile strength of 150 kgf / 10mm or more, measured by the American Society for Testing and Materials, ASTM D 5034. The method of claim 1,
Aramid fabric with a cladding strength of 150 kgf / 20mm or more, measured by the American Society for Testing and Materials, ASTM D 1683. A vehicle airbag comprising the aramid fabric according to any one of claims 1 to 7. 9. The method of claim 8,
The airbag is a vehicle airbag is a frontal airbag, a side curtain airbag, or a bumper type airbag.

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