CN1735721B - Inflatable two-layer fabrics - Google Patents

Abstract

The present invention relates to an inflatable two-layer fabric, and provides an inflatable two-layer fabric comprising two separated fabric layers, woven at the same time using a weaving machine, and an attachment area attaching said two fabric layers. Since the inflatable fabric of the present invention requires no sewing, it can significantly reduce manufacturing costs. Particularly, since all fabric layers are formed of a plain weave, airbags having a variety of shapes can be manufactured using a jacquard weaving machine. Further, since it has superior weaving property and smoothness, it can be utilized for side curtain airbags and other shock-absorbing products.

Description

Inflatable two-layer fabric

technical field

The present invention relates to inflatable two-layer fabrics, and more particularly, to inflatable two-layer fabrics that can be used in automotive airbags or life jackets. the

Background technique

Inflatable fabrics can be used in car airbags and life jackets. The inflatable fabric is particularly useful for side curtain airbags that deploy over the side glass to protect the head of an occupant from damage caused by the head colliding with the window glass or other structure. This fabric is very useful because if the car rolls over, the fabric should remain inflated for more than 5 seconds. the

In general, methods for producing inflatable fabrics for automobile airbags can be classified into: 1) methods of sewing, fusing or bonding two layers of fabrics; And partially crossed. the

However, the first method requires an additional sewing, fusing or bonding process in addition to preparing two-layer fabrics, thereby causing complicated procedures and increasing manufacturing costs. the

To solve the above problems, a second method has recently been proposed. the

The inflatable fabric has two separate fabric layers with a connection point between the fabric layers. When each single layer is rapidly inflated, the fabric surrounded by the connection points strongly interlocks the two layers so that no gas leaks. the

Methods of forming joints in said inflatable two-layer fabrics are suggested in USP-6,220,309, 5,098,125, 5,011,183 and 5,603,647. the

USP-6,220,309 discloses a two-layer fabric, the separation area (separator area) is formed by flat woven paper, and its connection area (attachment area) is formed by 2/2 mat weaving; USP-5,098,125 and 5,011,183 disclose a A two-ply fabric of which the separating areas are formed of plain weave and the joining areas are of 2/2 mat or 3/3 mat weave, 1/2 twill or 1/3 twill weave, or 5 harness satin satin); and USP-5,603,647 discloses a two-layer fabric, the separation area is formed by plain weave, mat weave or twill weave, and its connecting area is formed by 3/3 mat weave. Here, the separation area refers to an area in the two-layer fabric in which the two fabric layers (upper layer and lower layer) are separated from each other so that the two-layer fabric can be inflated by air or the like. By joining area is meant the area where the two separate fabric layers are in contact with each other. the

The above-mentioned two-layer fabric mainly utilizes the connection area formed by 3/3 mat weaving or 2/2 mat weaving. However, if the two layers of fabric are used alone, when the two separate layers are inflated, air can leak out at the join area. the

Contents of the invention

Therefore, the object of the present invention is to solve the above-mentioned problems and to provide an inflatable two-layer fabric with a dense joint area so that air leakage in the joint area can be minimized when the fabric is inflated, all fabrics of the fabric The layer is formed of plain weaving so that air bags having various forms can be produced using a jacquard, and can be produced without a sewing process, thereby significantly reducing production costs and having good weaving and smoothness. the

Another object of the present invention is to provide an automobile airbag comprising said inflatable two-layer fabric. the

In order to achieve these objects, the present invention provides an inflatable two-ply fabric comprising two separate fabric layers woven simultaneously by a loom and a connection point at the center of the connection area connecting said two fabric layers, said The air leakage per unit length of the connection area is less than 0.8L/min/cm (measured at 2.5kPa using Antares' Leak Tester 900Se). the

The two-layer fabric comprises a separate area (A, B) formed by two separate fabric layers and a connection point (C) joining the two separate fabric layers together. the

Said separation area (A, B) is formed by two separation fabric layers formed of plain weave. The left part (A) and right part (B) of the separation area are mirror images of each other centered on the connection point. Said connection point (C) is formed by plain weave by repeating the left part (A) and right part (B) of said separation area. Furthermore, it is preferred that the two-layer fabric is coated with a synthetic resin. the

The invention also provides an automobile airbag containing the inflatable two-layer fabric. Preferably the airbag is a side curtain airbag for passenger protection. the

Description of drawings

Figure 1 shows a fabric diagram explaining the repeating pattern (a) and its enlarged pattern (b) of a two-ply fabric consisting of two separate plain weave planes. the

Figure 2 is a cross-sectional view of a two-layer fabric of the present invention. the

Figure 3 shows a fabric diagram illustrating the repeating pattern in the left part (a) and right part (b) of the two-ply fabric shown in Figure 2. the

Figure 4 is a cross-sectional view of an inflatable two-layer fabric according to an embodiment of the present invention, the fabric being inflated with air. the

Figure 5 shows a method of measuring the pressure inside the balloon. the

Detailed ways

Next, the present invention is described in more detail. the

The present invention relates to an inflatable two-layer fabric which simplifies and reduces the cost of the manufacturing process for the production of vibration-absorbing products such as airbags, which enables the inflating of the separate areas to Gas leakage is minimized and has good weaving properties and surface smoothness, and it can be easily coated with synthetic resin. the

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. Figure 1 shows a fabric diagram illustrating the repeating pattern (a) of a two-ply fabric made of two separate plain weaves and its enlarged pattern (b), while Figure 2 is a cross-section of a two-ply fabric of the present invention picture. the

As shown in Figure 2, the two-layer fabric of the present invention comprises a separation zone (A, B) consisting of two separate fabric layers and a joining zone (C) connecting the two separate fabric layers together. The inflatable two-layer fabric of the present invention is prepared by simultaneously weaving two separate fabric layers (A and B of Fig. The layers of fabric form a mirror image. the

The main purpose of the fabric layer of the present invention is to provide fabric bags which are inflated with air or the like. This connection area isolates the bag causing inflation of the bag between the two separate fabric layers and is subject to the applied pressure when inflation gas is directed therein. the

In the present invention, a connecting region (C) may refer to a point, a thread or a surface in two separated fabric layers in a separating region (A, B) where the warp threads of the upper layer and the lower layer The weft threads form a single fabric, the warp threads of the lower layer and the weft threads of the upper layer form a single fabric, or the weft threads of the lower layer and the warp threads of the upper layer form a single fabric, so that the two fabric layers form a single layer in the joining area. Such a structure with connections is called a connected structure. When the connection structure is formed as a point, the connection structure is called a connection point; when the connection structure is formed as a line, the connection structure is called a connection line; when the connection structure is formed as a surface, the connection structure is called a connection surface. Connection points, connection lines, and connection surfaces together form connection regions. A weaving point refers to the area where the warp and weft threads cross each other, thus forming the fabric. the

The fabric having a structure separated into an upper layer and a lower layer and a connected structure can be classified into a separated structure (A, B of FIGS. 2 and 4 ) and a connected structure (C of FIGS. 2 and 4 ). Moreover, it can be divided into the following three regions: the region surrounded by the separation structure (B in Fig. 4) or the air-filled region; the connection region (C in Fig. 2 and Fig. 4); and the region outside the region surrounded by the connection structure (Fig. A) of 4, this area is not related to inflation. the

In FIG. 2, the left separation region (A) on the left side of the connection point and the right separation region (B) on the right side of the connection point are mirror images of each other, as shown in FIGS. 3 and 4 . the

In other words, the left separation region (A) is the exact repeating pattern shown in FIG. 3(a), while the right separation region (B) is the mirror image of FIG. b) The fully repeating pattern shown. They cross each other at contact points (C). the

In the present invention, the separation region (A, B) may be repeated two or more times to ensure multiple connection points. If so, the force generated during the inflation process is not concentrated on the first connection point, but can also be transferred to the second or more connection points to make the connection line stronger and prevent air leakage . the

Also, it is preferred that the inflatable two-layer fabric of the present invention is coated with a synthetic resin to reduce air leakage. As the synthetic resin, any synthetic resin used in fabric coating can be used. In view of airtightness and strength considerations, preferably a polysiloxane coating is suitable. the

The silicone resin coating is effective to fill the small voids in the two layers of fabric and it can be applied on either or both sides of the fabric. For the coating method, multi-step coating is preferred. If base coating and top coating are performed by multi-step coating, since the coating amount is reduced, airtightness can be improved and the fabric becomes more elastic. the

Preferably, the synthetic resin is applied at 40 to 150 g/m ² . If the application amount is less than 40 g/m ² , a large amount of air leaks from the air bag, so the inflated state cannot be maintained for more than 5 seconds. In addition, if the coating amount exceeds 150 g/m ² , the air bag becomes too thick, and the air bag may contact other structures during inflation.

In the two-layer fabric of the present invention, the separation layer has a double structure formed by plain weave (Fig. 1), while the connection structure is obtained by forming a mirror image centered on the connection area. the

Preferably two or more connection points can be formed to reduce air leakage. the

In order to ensure the airtightness of the two-ply fabric, it is very important to minimize fabric stretching by providing resistance to high pressure air etc. Therefore, the structure on the part where the two layers start to separate from each other or start to connect is a very important factor. the

In the two-layer fabric according to the invention, this problem is solved by using a plain weave which has a high resistance to external tensile forces in the fabric layer. It is preferable to use a high-density fabric with a coverfactor greater than 1900, which is defined by Equation 1 below, to provide good airtightness. If the cover factor is less than 1900, air tends to leak out during inflation. the

Equation 1

Cover factor (CF) = warp density × SQRT (warp denier) + weft density × SQRT (weft denier)

Wherein, the unit of warp thread density and weft thread density is "root/inch". the

The two-layer fabric of the present invention has an air leakage per unit length of less than 0.8 L/min/cm (measured at 2.5 kPa using Antares' Leak Tester 900Se) in the joining area. If the air leakage per unit length of the connecting area exceeds 0.8 L/min/cm, the automobile airbag made of the fabric cannot effectively protect passengers. the

In addition, each fabric layer of the two-layer fabric of the present invention has a thickness of less than 0.5 mm as determined by the ASTM D 1777 method and a stiffness value of less than 3.5 kgf, while the stiffness value is determined by the ASTM D 4032 endless belt method (circular band method) determination. If the thickness of each fabric layer exceeds 0.5mm, it is not easy to install the car airbag in the vehicle. Also, if the rigidity value exceeds 3.5kgf, the automobile airbag generally cannot be inflated due to gas pressure. the

For an airbag functioning as a side curtain airbag, when an initial pressure of 50 kPa is applied thereto, its internal pressure should be at least 6 kPa after 5 seconds. When the side curtain airbag is inflated under high temperature and pressure, the suture strength of the connection area (C in Figure 2) as determined by ASTM D 5822 method should be at least 80kg/in to prevent the airbag from tearing. In addition, in order to minimize gas leakage in the joint area during inflation and to prevent the fabric from melting due to heat, the modulus of rupture should not exceed 60%. In particular, since the side curtain airbag requires a relatively higher coating amount than conventional airbags, the side curtain airbag can maintain its strength for a long time even after the fabric is worn due to the vibration of the car. To meet these conditions, the inflatable two-layer fabric of the present invention needs to have the following properties: it has an internal pressure of at least 6 kPa after 5 seconds of applying a gas with an initial pressure of 50 kPa; it has a seam strength of at least 80 kg/in in the joining area ; a modulus of rupture of less than 60%; and having a strength retention ratio of at least 80%, as determined by the ASTM D 4157 method. If the strength maintenance ratio is less than 80%, the airbag may be torn during inflation. the

The present invention also provides a side curtain airbag for a vehicle comprising an inflatable two-layer fabric. When the vehicle rolls over, the side curtain airbag of the present invention remains inflated for at least 5 seconds. the

As noted above, the inflatable two-layer fabric of the present invention minimizes air leakage during inflation and is therefore useful for automotive airbags, life jackets, and other shock-absorbing products. In addition, since the two-layer fabric of the present invention does not require seaming, the production process can be simplified and thus the production cost can be reduced. the

Hereinafter, the present invention is described in more detail by way of examples. However, the following examples are only for the understanding of the present invention, not to limit the scope of the present invention. the

Example

The physical properties of the two-layer fabrics of the present invention were determined as follows. the

a) Air leakage per unit length in the connection area (L/min/cm):

Air leakage was measured using a measuring device equipped with an air pressure regulator, an airflow gauge, and a pressure gauge. Inject 2.5kPa of air pressure into the separation area where the two layers of fabric are cut to fully inflate the two layers of fabric. Then, measure the amount of air leakage per unit time (1 minute) of the two-layer fabric (unit: L), and then divide the amount of air leakage by the total connection length (unit: cm) to obtain the air leakage per unit length of the connection area , the total connection length is measured by a vernier caliper, tape measure or ruler. the

b) Coverage factor: Calculated by Equation 1 below. the

Equation 1

Cover factor (CF) = warp density × SQRT (warp denier) + weft density × SQRT (weft denier)

Wherein, the unit of warp thread density and weft thread density is "root/inch". the

c) Rigidity: measured by ASTM D 4032 endless belt method

d) Thickness of a single fabric layer: determined by ASTM D 1777 method. the

e) Suture strength: determined by ASTM D 5822 method. the

f) Strength maintenance ratio: determined by ASTM D 4157 method. the

Example 1

Using 426-denier polyamide multifilaments as warp and weft threads, a plain weave two-ply fabric (Fig. 2) was prepared with a jacquard loom, where the separation region (A) to the left of the joining point (C) has a Fig. 3 The structure of (a); the right separation region (B) at the connection point (C) is the mirror image of the left separation region (A) and has the structure of Figure 3 (b); the left separation region (A) and the right The separation regions (B) cross each other at connection points (C). The warp and weft densities are 52 per inch and the cover factor is 2131. Then, polysiloxane rubber was coated on both sides of the two-layer fabric by a two-step coating method (coating amount: 100 g/cm ² ). The fabric is cut and the air leakage per unit length over the joined area, thickness and stiffness values of the individual fabric layers are determined. The air leakage per unit length on the joint area is 0.6L/min/cm, the stiffness value is 2.5kgf, and the thickness of a single fabric layer is 0.4mm.

Example 2

Using 315-denier polyamide multifilaments as warp and weft threads, a plain weave two-ply fabric (Fig. 2) was prepared with a Jacquard loom, where the separation region (A) to the left of the joining point (C) has Fig. 3 The structure of (a); the right separation region (B) at the connection point (C) is the mirror image of the left separation region (A) and has the structure of Figure 3 (b); the left separation region (A) and the right The separation regions (B) cross each other at connection points (C). The warp and weft densities are 60 per inch and the cover factor is 2129. The connecting threads are enclosed by the plain weave structure over the entire fabric. Outside the enclosed connecting lines, except for the inflatable pattern, a planar structure is formed. The planar structure does not have to be a connected structure. the

Then, by the two-step coating method of base coating and top coating, polysiloxane rubber is coated on both sides of the two-layer fabric (coating amount: 100g/cm ² ) to stop air from joining points or Leaks out of weaving points. The fabric is cut and the air leakage per unit length over the joined area, thickness and stiffness values of the individual fabric layers are determined. The air leakage per unit length over this joint area is 0.7 L/min/cm, the stiffness value is 1.9 kgf, and the thickness of a single fabric layer is 0.39 mm.

Example 3

Two-layer fabrics were prepared in the same manner as in Example 2 except that the silicone rubber coating amount was changed to 90 g/m ² .

The single layer thickness of the two-layer fabric measured by ASTM D 1777 method is 0.39mm. The stiffness value determined by ASTM D 4032 endless belt method is 1.9kgf. An initial pressure of 50 kPa was applied to the airbag containing the fabric, and the internal pressure of the airbag was measured to be 12.5 kPa after 5 seconds. The seam strength of the joined area (C of Figure 2) measured by ASTM D5822 method was 119 kg/in, while the modulus of rupture was 43%. Also, the strength retention ratio determined by the coated fabric abrasion test according to ASTM D 4157 method is 90%. Therefore, the side curtain airbag has good installation properties and inflatability. the

Example 4

A two-layer fabric was prepared in the same manner as in Example 1 except that 420-denier nylon was used as the warp and weft. the

The single layer thickness of the two-layer fabric measured by ASTM D 1777 method is 0.4mm. The stiffness value measured by ASTM D 4032 endless belt method is 2.5kgf. An initial pressure of 50 kPa was applied to the airbag containing the fabric, and the internal pressure of the airbag was measured to be 9.5 kPa after 5 seconds. The seam strength of the joined area (C of Figure 2) measured by ASTM D5822 method was 123 kg/in, while the modulus of rupture was 49%. Furthermore, the strength retention ratio determined by the coated fabric abrasion test according to ASTM D 4157 method is 93%. Therefore, the side curtain airbag has good installation properties and inflatability. The internal pressure of the balloon was measured by the method shown in FIG. 5 . the

As shown in Figure 5, air is injected into the airbag, and the internal pressure increases. When the pressure reached the maximum, the gas injection was stopped, and the internal pressure of the balloon was measured 5.0 seconds later. Electronic air injection controllers are used to minimize operational errors. the

Comparative Example 1

Using 426-denier polyamide multifilament as the warp and weft, a two-layer fabric was prepared on a Jacquard loom, with the joining area formed by 2/2 mat weave and the separation area formed by plain weave. The warp and weft densities were 53/inch. Then, polysiloxane rubber was coated on both sides of the two-layer fabric by a two-step coating method (coating amount: 100 g/cm ² ). The fabric is cut and the air leakage per unit length over the joined area, thickness and stiffness values of the individual fabric layers are determined. The air leakage per unit length over this joint area is 0.9 L/min/cm, the stiffness value is 3.6 kgf, and the thickness of a single fabric layer is 0.52 mm.

Comparative Example 2

Two-layer fabrics were prepared in the same manner as in Example 4, except that the warp and weft densities were changed to 46/inch and the cover factor of a single fabric was 1880. the

The prepared fabric was coated in the same manner as in Example 1. The single layer fabric thickness measured by ASTM D 1777 method and the stiffness value measured by ASTM D 4032 endless belt method are satisfactory, they are 0.38mm and 1.9kgf respectively. An initial pressure of 50 kPa was applied to the airbag containing the fabric, and the internal pressure of the airbag was measured to be 5.8 kPa after 5 seconds. The suture strength of the joined area (C in Figure 2) measured by ASTM D 5822 method was 109 kg/in, while the modulus of rupture was 47%. Furthermore, the strength retention ratio determined by the coated fabric abrasion test according to the ASTM D 4157 method is 90%, thus having good installation properties. However, this internal pressure is too low, meaning that a large amount of air leaks out of the airbag. the

Comparative Example 3

A two-layer fabric prepared in the same manner as in Example 1 was coated by a one-step method (coating amount: 200 g/m ² ). The gas leakage per unit length measured at 2.5 kPa was 0.6 L/min/cm. Therefore, an airbag comprising the fabric has excellent airtightness. However, since the thickness of the fabric measured by the method of ASTM D 1777 is 0.52 mm, and the rigidity value measured by the method of ASTM D 4032 endless belt is 3.6 kgf, from the viewpoint of installation properties and inflatability for side curtain airbags, such Fabric is not up to the task.

The inflatable two-layer fabric of the present invention does not need to be stitched, so the production process can be simplified, thereby reducing the production cost. Also, because the connection area is rigid, air leakage can be minimized. In addition, the inventive fabric has excellent weaving properties and good surface smoothness for synthetic resin coatings. Therefore, the fabric of the present invention can be used in automobile airbags, life jackets and other shock-absorbing products. the

Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art will appreciate that various changes and substitutions can be made without departing from the spirit and scope of the invention as set forth in the appended claims. the

Claims (7)

1. An inflatable two-ply fabric comprising two separate fabric layers woven simultaneously on a loom and a joining area joining said two fabric layers, wherein each of said joining areas measured at 2.5 kPa The air leakage per unit length is less than 0.8L/min/cm, and Wherein said inflatable two-layer fabric comprises a separate area (A, B) formed by two separate fabric layers and a connection point (C) joining said two separate fabric layers together, wherein said separate area (A , The left separation region (A) structure and the right separation region (B) structure of B) are respectively located on the left and right sides of the connection point, and are mirror images of each other, the connection region is formed by plain weave, and the plain weave is formed by repeatedly knitting the left separation area (A) and the right separation area (B), wherein said inflatable two-layer fabric is coated with a synthetic resin, wherein the coating amount on one side of said inflatable two-layer fabric is 90 g/m ² or 100 g/m ² , Wherein, after applying an initial pressure of 50 kPa for 5 seconds, the inflatable two-layer fabric has an internal pressure equal to or greater than 6 kPa, it has a seam strength at the joint area equal to or greater than 80 kg/in, a modulus of rupture of less than 60% amount, and an abrasion intensity equal to or greater than 80% maintains the ratio. 2. The inflatable two-ply fabric as claimed in claim 1, which has a stiffness value equal to or less than 3.5 kgf. 3. The inflatable two-ply fabric of claim 1, wherein each single fabric layer comprises said inflatable two-ply fabric having a thickness equal to or less than 0.5 mm. 4. The inflatable two-layer fabric of claim 1 , wherein each individual fabric layer comprising said inflatable two-layer fabric has a cover factor equal to or greater than 1900, said cover factor being defined by Equation 1 below : Equation 1 Cover factor (CF) = warp density × SQRT (warp denier) + weft density × SQRT (weft denier), Wherein, the unit of warp thread density and weft thread density is "root/inch". 5. The inflatable two-ply fabric of claim 1, wherein said connection points are repeated two or more times. 6. An automobile airbag comprising the inflatable two-layer fabric as claimed in any one of claims 1, 4 and 5. 7. The automobile airbag according to claim 6, which is a side curtain airbag for a vehicle.

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