KR102124508B1 - Airbag Fabric and Method for Manufacturing The Same - Google Patents

Abstract

Disclosed is a fabric for an airbag and a method for manufacturing the airbag, which are not only advantageous for weight reduction of the airbag, but also have excellent airtightness, folding, and mechanical properties. The fabric for the airbag of the present invention includes a fiber substrate; And a coating layer on at least one side of the fiber substrate, wherein the fiber substrate is a fabric comprising, as warp and weft, a polyethylene terephthalate yarn having a tensile strength of at least 7.8 g/d and a cutting elongation of at least 15%. The cover factor is 1,600 to 1,800, and the weight per unit area of the coating layer is 5 to 15 g/m ² . The fabric for the airbag of the present invention has an air permeability of 1.0 cfm or less.

Description

Airbag fabric and method for manufacturing the same

The present invention relates to an airbag fabric and a method for manufacturing the same, and more particularly, to an airbag fabric and a method for manufacturing the airbag having excellent airtightness, folding property, and mechanical properties as well as advantageous for weight reduction of the airbag.

When the impact detection sensor detects an impact on the vehicle during a collision or rollover of a vehicle that is driving at a predetermined speed or higher, the airbag expands and expands by the high temperature and high pressure air provided from the inflator, thereby protecting the driver and passengers of the vehicle from accidents. do.

Items required for the fabric for airbags include i) low air permeability for smooth deployment in the event of a vehicle crash, ii) high strength and high heat resistance to prevent damage and rupture of the airbag itself, and iii) flexibility to reduce shock to the passengers, etc. There is this.

On the other hand, since the airbag is manufactured in a certain shape and then mounted in a folded state on a steering wheel, side structure, etc. of a vehicle, it is required to have excellent folding and packability.

Generally, the fabric for the airbag includes a fiber substrate.

The fiber substrate may be a plain weave or a basket weave, and is conventionally made of polyamide yarn such as nylon 66. However, while nylon 66 has excellent impact resistance, it is not satisfactory in terms of moisture resistance, light resistance, and shape stability, and has a disadvantage in that raw material cost is also high.

In order to solve the disadvantages of nylon 66, the use of polyester yarn has been proposed. However, because the polyester has a higher stiffness than nylon 66 due to its molecular structure, the fabric for airbags made of conventional polyester yarns has poor folding and storage properties. In addition, the carboxyl end group in the polyester molecular chain attacks the ester bond under high temperature and high humidity conditions, causing molecular chain cleavage. Therefore, the airbag fabric made of polyester yarn has a problem that mechanical properties are severely deteriorated under conditions of high temperature and high humidity.

On the other hand, as environmental problems have emerged, the recent development of automobile-related technologies is focused on improving fuel efficiency, and light weight of various parts is required to improve fuel efficiency of automobiles. Therefore, considering that 6 to 12 airbags are installed in one vehicle, an airbag having a lower weight than a normal airbag is required while satisfying basic properties required for the airbag.

As a method for reducing the weight of the airbag, a low-density fiber substrate having a low warp yarn density can be used. However, the fabric for airbags made of a low-density fiber base has the disadvantage that its airtightness is insufficient.

In order to improve the airtightness of the airbag fabric made of a low-density fiber substrate, a coating agent comprising a rubber component, for example, a coating agent having a viscosity of 15,000 to 400,000 cP containing a silicone resin, is applied on the fiber substrate by knife coating. A coating layer was formed. However, according to the conventional method for forming a coating layer, in order to secure the airtightness required for the fabric for the airbag, the application amount of the coating layer had to exceed 15 g/m ^2, thereby limiting the weight reduction of the airbag.

Accordingly, the present invention relates to an airbag fabric and a method of manufacturing the same, which can prevent problems caused by limitations and disadvantages of the related art.

One aspect of the present invention is to provide a fabric for an airbag that is not only advantageous for weight reduction of the airbag, but also has excellent airtightness, folding properties, and mechanical properties.

Another aspect of the present invention is to provide a method for manufacturing a fabric for an airbag, which is not only advantageous for weight reduction of the airbag, but also has excellent airtightness, folding property, and mechanical properties.

In addition to the above-mentioned aspects of the present invention, other features and advantages of the present invention will be described below, or it will be clearly understood by those skilled in the art from the description.

According to one aspect of the present invention as above, the fiber substrate; And a coating layer on at least one side of the fiber substrate, wherein the fiber substrate is a fabric comprising, as warp and weft, a polyethylene terephthalate yarn having a tensile strength of at least 7.8 g/d and a cutting elongation of at least 15%. The cover factor defined by the following formula is 1,600 to 1,800, the weight per unit area of the coating layer is 5 to 15 g/m ² , and the air permeability measured by the American Society for Testing and Materials ASTM D 737 is 1.0 cfm or less, Fabrics for airbags are provided.

Equation: CF = W _D ×W _T ^1/2 + F _D ×F _T ^1/2

Here, CF is the cover factor, W _D is the slope density (bones/inch), W _T is the slope fineness (denier), F _D is the weft density (bones/inch), and F _T is the weft fineness (denier). to be.

The polyethylene terephthalate yarn has a fineness of 480 to 650 denier, and the fabric may have a warp density and a weft density of 35 to 40 th/inch.

The coating layer may include a silicone resin.

According to another aspect of the present invention, using a polyethylene terephthalate yarn having a tensile strength of 7.8 g / d or more and a cutting elongation of 15% or more as warp and weft to prepare a fabric having a cover factor (CF) of 1,600 to 1,800; Preparing a liquid silicone rubber coating agent having a viscosity of 20 to 100 cP measured at 25°C; Spraying the liquid silicone rubber coating agent through the nozzle toward the fabric; And drying and curing the liquid silicone rubber coating agent applied on the fabric through the spraying step to form a coating layer, wherein the weight per unit area of the coating layer is 5 to 15 g/m ² , the fabric for airbag A method of manufacturing is provided.

The liquid silicone rubber coating agent may be sprayed toward the fabric at a pressure of 0.1 to 1 kgf/cm ² .

When the liquid silicone rubber coating agent is sprayed toward the fabric, a tension of 1 N/m or less in the width direction may be applied to the fabric.

All of the above general description and the following detailed description are only intended to illustrate or describe the present invention, and should be understood to provide a more detailed description of the invention of the claims.

According to the present invention, despite being made of a relatively low density fiber substrate for weight reduction of the airbag, an airbag fabric excellent in airtightness, folding property, and mechanical properties can be provided.

Specifically, it is possible to implement a lightweight airbag by manufacturing a fabric for an airbag using a low-density fabric having a low cover factor of 1,600 to 1,800.

In addition, in manufacturing the low-density fabric, by using a polyethylene terephthalate yarn having a high tensile strength of 7.8 g/d or more and a high elongation of cut of 15% or more, folding and mechanical properties of the fabric for the airbag can be improved.

In addition, the liquid silicone rubber coating agent having a low viscosity of 20 to 100 cP is uniformly coated on the low density fabric with a small application amount of 5 to 15 g/m ² through a spray coating method, thereby increasing the weight of the fabric for the airbag. While minimizing, it is possible to prevent a decrease in airtightness due to the use of low density fabrics.

The accompanying drawings are intended to help the understanding of the present invention and constitute a part of the present specification, and exemplify embodiments of the present invention, and describe the principles of the present invention together with a detailed description of the present invention.
1 is a cross-sectional view of an airbag fabric according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the embodiments described below are presented for illustrative purposes only to aid in a clear understanding of the present invention, and do not limit the scope of the present invention.

It will be apparent to those skilled in the art that various changes and modifications of the present invention are possible without departing from the spirit and scope of the present invention. Accordingly, the present invention includes all modifications and variations falling within the scope of the invention and equivalents described in the claims.

Hereinafter, the fabric 100 for an airbag according to an embodiment of the present invention will be described with reference to FIG. 1. 1 is a cross-sectional view of an airbag fabric according to an embodiment of the present invention.

As illustrated in FIG. 1, the fabric 100 for an airbag of the present invention includes a fiber substrate 110 and a coating layer 120 on the fiber substrate 110.

In FIG. 1, although the fabric 100 in which the coating layer 120 is formed only on one surface of the fiber substrate 110 is illustrated, the present invention is not limited to this, and the fiber substrate of the coating layer 120 ( It may be formed on both sides of 110).

As described above, the fiber substrate 110 of the present invention has a cover factor defined by the following formula as a low-density fabric for meeting the weight reduction requirements of the airbag, and is 1,600 to 1,800.

Equation: CF = W _D ×W _T ^1/2 + F _D ×F _T ^1/2

Here, CF is the cover factor, W _D is the slope density (bones/inch), W _T is the slope fineness (denier), F _D is the weft density (bones/inch), and F _T is the weft fineness (denier). to be.

Even if the coating layer 120 is formed when the cover factor of the fiber substrate 110 is less than 1,600, the airtightness and pressure-resistance performance of the airbag fabric 100 cannot satisfy the needs of the industry. On the other hand, when the cover factor exceeds 1,800, the weight of the airbag fabric rises and the folding property of the airbag fabric 100 decreases, and the weight of the airbag cannot be realized.

The fiber substrate 110 includes warp yarns 111 and weft yarns 112 each having a low fineness of 480 to 650 denier, and has a low warp density and low weft density of 35 to 40 th/inch. If the density of the warp yarns is less than 35 th/inch, the fabric 100 for the airbag cannot have satisfactory toughness, and when the density of the warp yarns exceeds 40 th/inch, the folding and storage properties of the airbag deteriorate and are satisfactory. Lightweight airbags at a level cannot be implemented.

From the viewpoint of flexibility, smoothness of the coated surface, etc., it is preferable that each of the warp 111 and the weft 112 is a multifilament including 72 or more filaments 111a and 112a.

According to the present invention, a polyethylene terephthalate (PET) yarn having a high tensile strength of 7.8 g/d or more and a high elongation of cut of 15% or more is used as the warp yarns 111 and the weft yarns 112. By manufacturing the fiber substrate 110 using a polyethylene terephthalate (PET) yarn having such high strength, high elongation and high shrinkage, the fabric for airbag 100 of the present invention has excellent folding properties despite the use of low density fabric And mechanical properties.

As described above, the fabric 100 for an airbag of the present invention further includes a coating layer 120 including a rubber component on at least one surface of the fiber substrate 110.

The coating layer 120 may include silicone resin. For example, the coating layer 120 may be formed of a liquid silicon rubber (LSR) coating agent.

The coating layer 120 may further include 0.1 to 1 part by weight of a wetting agent, 2 to 5 parts by weight of a crosslinking agent, and 5 to 20 parts by weight of a flame retardant based on 100 parts by weight of the silicone resin.

The wetting agent is for allowing the silicone resin to penetrate well and uniformly into the fiber substrate 110, and a silicone-based wetting agent may be used.

The crosslinking agent improves the adhesion between the fiber substrate 110 and the coating layer 120.

The flame retardant is intended to improve the flame retardant properties of the fabric 100 for an airbag, and a non-halogen phosphorus flame retardant may be used.

In addition to the additives described above, the coating layer 120 of the present invention is 0.1 to 2 parts by weight of other additives (silicone-based anti-blocking agent and/or slip agent) to improve the surface properties of the fabric 100 agent)].

The coating amount of the coating layer 120 on the fiber substrate 110 may be 5 to 15 g / m ² . When the coating amount of the coating layer 120 is less than 5 g/m ² , the airbag fabric 100 cannot secure sufficient airtightness (ie, air permeability of 1.0 cfm or less). On the other hand, when the coating amount of the coating layer 120 exceeds 15 g/m ² , despite the use of the low-density fiber substrate 110, it is not possible to sufficiently meet the needs of the airbag weight reduction in the industry.

The air permeability of the fabric 100 for an airbag of the present invention as measured through the American Society for Testing and Materials ASTM D 737 is 1.0 cfm or less.

Hereinafter, a method for manufacturing the airbag fabric 100 according to an embodiment of the present invention will be described in detail.

First, as the fiber substrate 110, a polyethylene terephthalate (PET) yarn having a tensile strength of 7.8 g/d or more and a cutting elongation of 15% or more is used as warp and weft to prepare a fabric having a cover factor of 1,600 to 1,800. .

As described above, the fabric can be made by weaving to a low warp yarn density of 35 to 40 th/inch using a polyethylene terephthalate (PET) yarn with a low fineness of 480 to 650 denier. From the viewpoint of flexibility, smoothness of the coated surface, etc., it is preferable that the yarn is a multifilament comprising 72 or more filaments 111a and 112a.

Subsequently, a liquid silicone rubber coating agent having a viscosity of 20 to 100 cP measured at 25°C is prepared.

The silicone coating agent commonly used in the manufacture of fabrics for airbags is a coating agent having a high viscosity of 15,000 to 400,000 cP, and such a high viscosity coating agent is mainly applied on a fiber substrate through a knife coating method. due to the limitations of the method was difficult to control the coating amount to less than 15 g / m ^2, force 15 g / m ² when applying the following coating amount of is the uniformity of the serious damage to the coating decreased mechanical properties such as peel strength Of course, the airtightness of the fabric for the airbag was deteriorated. On the other hand, as described above, when the coating amount of the coating agent exceeds 15 g / m ² , it is not possible to sufficiently meet the industry's airbag weight reduction needs.

Therefore, according to the present invention, a spray coating method capable of uniformly applying a small amount of coating agent on the low density fabric is adopted instead of the knife coating method. In addition, a liquid silicone rubber (LSR) coating agent having a low viscosity suitable for a spray coating method, for example, a viscosity of 30 to 80 cP, is used for forming the coating layer 120 of the present invention.

As described above, the liquid silicone rubber (LSR) coating agent may further include 0.1 to 1 part by weight of a wetting agent, 2 to 5 parts by weight of a crosslinking agent, and 5 to 20 parts by weight of a flame retardant based on 100 parts by weight of the silicone resin. .

Subsequently, the liquid silicone rubber coating agent is sprayed toward the fabric through a nozzle.

The liquid silicone rubber coating agent may be sprayed at a pressure of 0.1 to 1 kgf/cm ² toward the fabric, and when the liquid silicone rubber coating agent is sprayed toward the fabric, in the width direction of the fabric, 1 N/m or less Tension can be applied.

In order to improve the weaving properties of the low-density fabric, when applying an emulsion or a sizing agent to the polyethylene terephthalate (PET) yarn before weaving, refining for removing the sizing agent or sizing agent from the fiber base 110 before the spraying step The step and the washing step of the refined fiber substrate 110 may be further performed.

Subsequently, the liquid silicone rubber coating agent applied on the fiber substrate 110 is dried and cured through a spraying step to form a coating layer 120. The spray amount of the coating agent is adjusted in the spraying step so that the weight per unit area of the coating layer 120 is 5 to 15 g/m ² .

According to the present invention, the weight per unit area of the coating layer 120 is 15 g/m ² or less by uniformly applying a liquid silicone rubber (LSR) coating agent having a low viscosity of 30 to 80 cP on the fiber substrate through a spray spraying method. Despite this, the fabric 100 for an airbag having a low air permeability of 1.0 cfm or less can be manufactured.

The drying and curing step may be performed, for example, in a tenter oven. Sudden high temperature curing may cause damage to the coating layer 120, so the drying and curing steps may be performed in multiple stages. For example, after pre-drying the fiber substrate 110 coated with the liquid silicone rubber coating agent at 80 to 110°C, gradually increasing the drying temperature and finally drying completely at 130 to 180°C ( That is, it can be completely cured or heat-set).

The fabric 100 for the airbag of the present invention is made of airbag cushions, such as a driver airbag, a passenger airbag, a side airbag, and the like, through an altar and sewing process.

Hereinafter, effects of the present invention will be described through specific examples and comparative examples of the present invention. However, the following examples are only to aid the understanding of the present invention, but they do not limit the scope of the present invention.

Example One

Made of 136 filaments, 40 × 40 th/inch of polyethylene terephthalate (PET) yarn with a total fineness of 500 denier, a tensile strength of 8.6 g/d, and a cutting elongation of 17.5% as a warp and weft yarn Fabrics with a cover factor of 1,789 were prepared by performing plain weave with a warp yarn density.

Subsequently, a liquid silicone rubber (LSR) coating agent having a viscosity of 50 cP is sprayed toward the fabric at a spray pressure of 0.5 kgf/cm ² through a spray coating method, and then dried and cured to perform a drying and curing process, thereby making the weight per unit area of 15 g/m ² A coating layer having a was formed on the fabric.

Example 2

The fabric for the airbag was completed in the same manner as in Example 1, except that the weight per unit area of the coating layer was 13 g/m ² .

Example 3

The PET yarn had a tensile strength of 8.8 g/d and a cutting elongation of 18%, and the above-described practice was performed except that the weft density of the fabric was 38×38 th/inch (ie, the cover factor of the fabric was 1,699). The fabric for the airbag was completed in the same manner as in Example 1.

Example 4

The fabric for the airbag was completed in the same manner as in Example 3, except that the weight per unit area of the coating layer was 13 g/m ² .

Comparative example One

The PET yarn had a tensile strength of 6.6 g/d and a cutting elongation of 10%, and the weft density of the fabric was 49×49 th/inch (ie, the cover factor of the fabric was 2,191), and the spray pressure of the coating agent was 1.0 kgf. /cm ^2, and the weight per unit area of the coating layer was 8 g / m ² , except that the fabric for the airbag was completed in the same manner as in Example 1.

Comparative example 2

The PET yarn had a tensile strength of 6.9 g/d and a cutting elongation of 13%, the viscosity of the coating agent was 200 cP, the injection pressure of the coating agent was 3 kgf/cm ^2, and the weight per unit area of the coating layer was 5 g/m ² The fabric for the airbag was completed in the same manner as in Comparative Example 1, except that it was.

Comparative example 3

Except that the weft density of the fabric was 33×33 th/inch (ie, the cover factor of the fabric was 1,529), the spray pressure of the coating agent was 0.5 kgf/cm ^2, and the weight per unit area of the coating layer was 15 g/m ² Then, the fabric for the airbag was completed in the same manner as in Comparative Example 1.

Comparative example 4

Comparative Example, except that the PET yarn had a tensile strength of 6.9 g/d and a cutting elongation of 13%, and the weft density of the fabric was 33×33 th/inch (ie, the cover factor of the fabric was 1,529). The fabric for the airbag was completed in the same manner as 1.

The tensile strength, cutting elongation, stiffness, packability, and air permeability of the airbag fabrics of the examples and comparative examples prepared as above were measured by the following methods, and the in-plate deployment test was as follows. It was carried out together, and the results are shown in Table 1 below.

* The tensile strength/ Cutting elongation

Tensile strength (kgf/inch) and cut elongation (%) of the warp direction and the weft direction of each airbag fabric were measured through ASTM D 5034, the American Society for Testing and Materials. Specifically, the specimen was prepared by cutting the fabric, and the specimen was fixed to the lower clamp of the measuring device, and then the upper clamp was moved upward to measure the strength and elongation when the specimen was broken.

* Stiffness

The ductility (N) of each airbag fabric was measured through the American Materials Testing Association standard ASTM D 4032. Specifically, a specimen having a diameter of 100 mm × 200 mm was prepared, and the specimen folded in half on a pedestal (102 mm × 102 mm × 6 mm) having a hole of 38.1 mm diameter was placed, and the specimen was pressed with a bar from above to fabric into the hole of the pedestal. The force of pushing and descending was measured.

* Storage ( packability )

The storage property (cm ³ ) of each airbag fabric was measured through the American Material Testing Association standard ASTM D 6478.

* Air permeability

The air permeability (cfm) of each airbag fabric was measured through the American Materials Testing Association standard ASTM D 737.

* Inflator Deployment test

When the airbag cushions made of the fabric for each airbag were deployed with an inflator, pass/fail was determined by whether the airbag cushions were damaged.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Yarn material PET PET PET PET PET PET PET PET Total fineness
(denier) 500 500 500 500 500 500 500 500 The tensile strength
(g/d) 8.6 8.6 8.8 8.8 6.6 6.9 6.6 6.9 Cutting elongation
(%) 17.5 17.5 18 18 10 13 10 13 textile Inspector density
(th/inch) 40×40 40×40 38×38 38×38 49×49 49×49 33×33 33×33 Cover factor 1,789 1,789 1,699 1,699 2,191 2,191 1,529 1,529 Coating Viscosity (cP) 50 50 50 50 50 200 50 50 Injection pressure
(kgf/cm ² ) 0.5 0.5 0.5 0.5 1.0 3 0.5 1.0 Application amount (g/m ² ) 15 13 15 13 8 5 15 8 fabric The tensile strength
(Inclination x weft)
(kgf/inch) 287×278 284×273 268×270 265×268 254×250 264×259 166×168 175×170 Cutting elongation
(Inclination x weft)
(%) 30×28 30×28 29×27 29×27 23×22 24×23 16×15 17×16 Lecture degree (N) 14 13 14 12 19 18 11 10 Storability (cm ³ ) 1950 1930 1860 1840 2200 2050 1700 1670 Air permeability
(cfm) 0.5 0.7 0.6 0.8 1.8 2.1 2.8 3.3 Inflator
Test pass pass pass pass fail fail fail fail

100; Fabric for airbag 110: Fiber base
111: slope 112: weft
120: coating layer

Claims (6)

delete delete delete Preparing a fabric having a cover factor of 1,600 to 1,800 defined by the following formula using polyethylene terephthalate yarn having a tensile strength of 7.8 g/d or more and a cutting elongation of 15% or more as warp and weft;
Formula: CF = W _D ×W _T ^1/2 + F _D ×F _T ^1/2
[Where CF is the cover factor, W _D is the slope density (bones/inch), W _T is the slope fineness (denier), F _D is the weft density (bones/inch), and F _T is the weft fineness (denier )being]
Preparing a liquid silicone rubber coating agent having a viscosity of 20 to 100 cP measured at 25°C;
Spraying the liquid silicone rubber coating agent through the nozzle toward the fabric; And
Drying and curing the liquid silicone rubber coating agent applied on the fabric through the spraying step to form a coating layer,
The weight per unit area of the coating layer is 5 to 15 g/m ² ,
Method for manufacturing airbag fabric. The method of claim 4,
The liquid silicone rubber coating agent is injected at a pressure of 0.1 to 1 kgf/cm ² toward the fabric,
Method for manufacturing airbag fabric. The method of claim 5,
When the liquid silicone rubber coating agent is sprayed toward the fabric, a tension of 1 N/m or less is applied to the fabric in the width direction,
Method for manufacturing airbag fabric.

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