KR101297795B1 - Fabric used in manfacturing air bag - Google Patents

Abstract

The present invention relates to a fabric for an air bag, comprising: a base layer (1) formed of a synthetic fiber fabric having a heat capacity of 620 J / g or more; It is laminated on the substrate layer (1) and comprises a nanofiber web (2) consisting of nanofibers having a single yarn fineness of 1,000 nm or less, and the air permeability measured by ASTM D 737 method at a pressure difference of 125 Pa is 2.0 ft. ^It is characterized by being ³ / min (2.0 CFM) or less.

The present invention is excellent in airtightness as the air permeability is lowered even if the nanofiber web is laminated on the base layer to form a separate rubber coating layer.

In addition, the present invention has a high thermal capacity of the substrate layer, the thermal characteristics are also good.

Airbag, fabric, air permeability, air tightness, nanofiber, web, electrospinning, lamination.

Description

Fabric used in manfacturing air bag}

1 is a schematic cross-sectional view of a fabric for an airbag according to the present invention.

2 is an electron micrograph of the polyamide 6 nanofiber web prepared in Example 1. FIG.

3 is a process schematic diagram of an example of an electrospinning scheme.

The present invention relates to an airbag fabric, and more particularly, to an airbag fabric having low air permeability and excellent thermal characteristics by laminating a nanofiber web on a substrate layer.

Hereinafter, in the present invention, a nanofiber is used as a term meaning a fiber having a single yarn fineness of 1,000 nm or less, and a nanofiber web is used as a term meaning a web (Web) in which the nanofibers are sequentially stacked.

Recently, various types of transportation, particularly automobiles, have been in practical use for airbag systems to protect passengers from impacts in the event of a crash. These airbags are usually stored in the steering wheel and dashboard of a car, so the smaller the airbag, the better. And since the air bag is repeatedly subjected to high temperature heat and vibration by the automobile for a long time, it has to have excellent thermal characteristics and wear resistance.

The airbag is composed of the front panel, which is the driver side, and the back panel or the side panel, which is the inplate side. In-plate attachment holes are formed in the back panel or side panel, and vent holes are selectively formed. The in-plate attachment hole is a hole for injecting the high pressure gas into the airbag, and the vent hole is a hole for discharging the high pressure gas in the airbag for shock and suffocation prevention of the driver and passenger.

Airbags to protect the head and body of the passenger in the event of an automobile accident require characteristics such as thermal properties, airtightness, strength, flexibility and light weight. In the event of an accident, hot, high-pressure gas from the inflates inflates the airbag to protect passengers.

At this time, the high-temperature, high-pressure gas generated in the inflate is in direct contact with the fabric of the airbag material, causing the airbag to expand. If the airbag fabric has low airtightness, the gas of high temperature and high pressure escapes to the surface of the fabric and comes into direct contact with the passenger's human body, causing harmful effects such as choking.

The airtightness of the fabric for airbags without rubber coating is less than 8.0ft ³ / min (hereinafter referred to as CFM) measured by ASTM D 737 at a pressure difference of 125 Pa, similar to the pressure on the fabric during actual airbag deployment. More preferably, it becomes 2.0 CFM or less.

In addition, it is preferable that the fabric for airbags has a heat capacity (hereinafter referred to as "Hc") of 620 J / g or more. When the heat capacity is low, the mechanical properties are greatly reduced when the high temperature heat is repeatedly applied or when contacted with the hot high pressure gas injected from the in-plate.

In addition, the fabric for the airbag is to be expanded rapidly by the high temperature and high pressure gas, so it must have excellent tensile strength. Preferably the tensile strength should be at least 171 kgf / inch as measured by ASTM D 5034 method. In addition, the fabric for the airbag should be provided with flexibility and lightness to improve the storage in the airbag module, and to reduce the weight of the vehicle.

Preferably the thickness should be 0.4 mm or less and the weight should be 290 g / m 2 or less.

As a conventional technique for improving airtightness of the fabric for airbags, that is, reducing air permeability, a method of forming a rubber coating layer by coating a rubber component such as silicone rubber on a base fabric has been widely used. However, the conventional method may reduce the air permeability, but the process of coating the rubber component is complicated, and the fabric for the airbag becomes stiff when the rubber component is coated.

As another conventional technique, a method of manufacturing a non-coating type airbag fabric without a coating layer of rubber components by increasing the weft weave density during fabric manufacturing has been widely used, but the weft weave has a high weft weave density. There was a problem of this deterioration.

An object of the present invention is to manufacture a fabric for an air bag that can be manufactured with a simple manufacturing process and a high weaving efficiency at the same time the nanofiber web is laminated on the substrate layer excellent in thermal properties and greatly improved hermeticity.

The present invention is to provide a fabric for airbags having excellent airtightness and excellent thermal properties even if the nanofiber web is laminated on the substrate layer without forming a separate rubber coating layer.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, the airbag according to the present invention includes a base layer 1 formed of a synthetic fiber fabric having a heat capacity of 620 J / g or more; It is laminated on the substrate layer (1) and comprises a nanofiber web (2) consisting of nanofibers having a single yarn fineness of 1,000 nm or less, and the air permeability measured by ASTM D 737 method at a pressure difference of 125 Pa is 2.0 ft. ^It is characterized by being ³ / min (2.0 CFM) or less.

1 is a schematic cross-sectional view of a fabric for an airbag according to the present invention.

The nanofiber web has a single yarn fineness of 1,000 nm or less and consists of nanofibers. 2 is an electron micrograph of the polyamide 66 nanofiber web prepared in Example 1. FIG.

The nanofibers may be prepared by the electrospinning method shown in FIG. 3 as polyurethane fibers, polyester fibers, polyamide 66 fibers, polyamide 46 fibers, wholly aromatic polyamide fibers, and the like.

3 is a process schematic of a typical electrospinning example.

Electrospinning was first introduced in Germany in the 1930s as a relatively simple way to produce nanofibers of tens to hundreds of nanometers in diameter. However, the technology of the time was limited to commercialization of this technology, so it was not received attention, and research began again until the 1970s, and full-scale research began only after the 2000s.

Electrospinning applied a high voltage of several thousand to tens of thousands of volts to the polymer solution, and the force of the tangential vector exceeding the surface tension of the solvent was applied from the polymer solution to form a fine polymer jet from the polymer solution. The band advances rapidly toward the object. The jets of polymer jets are then dispersed and scattered back into a number of fine fibers, which have a diameter of tens to hundreds of nanometers.

Electrospinning can be used to produce nanofiber webs as shown in Figure 2 consisting of nanofibers having a thickness of several tens to hundreds of nanometers from a polymer solution, using them for high functional clothing, ultra-precision filters, cell culture materials (scaffold). High performance products, such as) can be obtained.

In order to commercially manufacture a nanofiber web, Korean Patent No. 0412241, Korean Patent No. 0422459, and Korean Patent Publication No. 2005-15610 propose a method of electrospinning a polymer solution through a plurality of nozzles.

Specifically, in the above method, as shown in FIG. 3, the polymer solution is supplied to the plurality of nozzles 3 under high voltage through the metering pump 2, and then a high voltage having a charge opposite to the nozzle is applied. A nanofiber web is produced by electrospinning on a fiber substrate positioned on the hanging collector 4.

3 is a process schematic diagram of an example of an electrospinning method.

In the present invention, the method for producing the nanofibers is not particularly limited.

On the other hand, the substrate layer 1 may be composed of polyamide 66 fibers, polyamide 46 fibers, wholly aromatic polyamide fibers and the like with a heat capacity (Hc) of 620 J / g or more.

The base layer 1 is manufactured by weaving into a plain weave, a basket weave or a twill weave using the above-described synthetic fiber yarn as warp and weft yarns.

The nanofibers may be prepared by spinning the nanofibers described above by electrospinning on the substrate layer 1 prepared as described above, thereby manufacturing a fabric for an airbag according to the present invention.

Airbag fabric according to the present invention is airtightness, specifically air permeability measured by the ASTM D 737 method at 125Pa pressure difference is less than 2.0 CFM.

In addition, the present invention has a tensile strength of 171kgf / inch or more measured by the ASTM D 5034 method, the thickness is 0.4mm or less, the weight is 290g / ㎡ or less.

In addition, the present invention is excellent in thermal properties to maintain the physical properties as it is built in a car for a long time heat of high temperature sprayed from the in-plate or in contact with the gas.

On the other hand, the heat capacity (Hc) of the base layer is measured by the following method.

·heat capacity

Heat capacity (Hc) is measured by ASTM E 1269 method using differential scanning calorimeter (DSC).

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

However, the scope of the present invention is not limited by the following examples.

Example  One

Weaving plain weave with a weft yarn density of 41 / inch × 41 / inch using polyamide 66 filament with a heat capacity of 623 g / J, single yarn fineness of 6 deniers and total yarn fineness of 630 deniers as warp and weft yarns. The layer was prepared.

Next, polyamide 66 was dissolved in formic acid at 8% concentration to prepare a polyamide 66 solution (spinning solution) at 25 ° C., which was then supplied to the spinning solution tank 1 as shown in FIG. 3. The polyamide 66 solution (spinning solution) is fed through a metering pump (2) to a plurality of nozzles 3 under high voltage, which are then passed through a high voltage collector 4 with opposite charge to the nozzle. Electrospinning on the substrate layer to prepare a fabric for the air bag.

The results of evaluating various physical properties of the prepared airbag fabric are shown in Table 1.

Example  2

A polyurethane solution (spinning solution) prepared by dissolving a polyurethane resin in 8% concentration of dimethylformamide on the base layer of polyamide 66 prepared in Example 1 was electrospun in the same manner as in Example 1 for airbags. Fabric was prepared.

The results of evaluating various physical properties of the prepared airbag fabric are shown in Table 1.

Comparative Example  One

A base layer of polyamide 66 prepared in Example 1 (without lamination of nanofiber webs) was used as the fabric for the airbag.

The results of evaluating various physical properties of the airbag fabric are shown in Table 1.

division Air permeability
(CFM) Heat capacity of substrate layer (Hc)
(J / g) Thickness (mm) Weight (g / ㎡) The tensile strength
(kgf / inch) Example 1 1.3 623 0.35 240 230 Example 2 1.2 623 0.35 240 231 Comparative Example 1 3.0 623 0.35 240 229

In the present invention, even if the nanofiber web is laminated on the base layer without forming a separate rubber coating layer, the air permeability is low, and thus the airtightness is excellent.

Claims (4)

A base layer (1) formed of a synthetic fiber fabric having a heat capacity of 620 J / g or more; It is laminated on the substrate layer (1) and comprises a nanofiber web (2) consisting of nanofibers having a single yarn fineness of 1,000 nm or less, and the air permeability measured by ASTM D 737 method at a pressure difference of 125 Pa is 2.0 ft. Airbag fabric, characterized in that less than ³ / min (2.0 CFM). 2. The nanofiber web according to claim 1, characterized in that the nanofiber web 2 is composed of one or more fibers selected from the group consisting of polyurethane fibers, polyester fibers, polyamide 66 fibers, polyamide 46 fibers and wholly aromatic polyamides. Fabric for airbags made of. The fabric of claim 1, wherein the base layer (1) is composed of one or more fibers selected from the group consisting of polyamide 66 fibers, polyamide 46 fibers, and wholly aromatic polyamide fibers. The fabric of claim 1, wherein the nanofiber web (2) is produced by electrospinning.

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