JP2006160102A - Airbag cover and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag cover having the mechanical characteristics, the lightweightness and the compactness, and further having the excellent flame retardancy and excellent storage and assembly workability of an airbag base cloth, and an airbag storage member consisting thereof. <P>SOLUTION: The airbag cover is formed of a cloth in which the ratio S/t (N/mm<SP>2</SP>) of the tensile strength S(N/mm) to the cloth thickness t (mm) is within a range of 30-170 N/mm<SP>2</SP>both in the longitudinal direction and in the transverse direction. Preferably, the unit weight of the cloth is in a range of 30-120 g/mm<SP>2</SP>, and the cloth thickness t is in a range of 0.05-0.15 mm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an airbag cover that has both mechanical characteristics, light weight, and compactness, and is excellent in storing and assembling work of an airbag base fabric, and an airbag storage member comprising the airbag cover.

  In recent years, various types of airbags have been developed to ensure the safety of passengers in the event of accidents in various transportation facilities, especially automobiles, and their effectiveness has been recognized and their practical application is rapidly progressing. They include driver airbags that protect passengers from frontal crashes, passenger airbags, knee airbags that protect the lower limbs of passengers, and side airbags and curtain airbags that protect passengers from side impacts. It is popular. Such an airbag inflates the bag when the vehicle collides, restrains the movement of the occupant, and protects the occupant from the impact of the collision. The configuration of the airbag includes an inflator that is a gas generator, an airbag base fabric that is inflated by gas, an airbag cover that holds the folded airbag base fabric, and an airbag storage member.

  After the airbag base fabric mounted on the vehicle is folded in a predetermined manner, the airbag base fabric is brazed so as not to lose its shape, and then the airbag base fabric is covered so as to cover the airbag base fabric folded by the airbag cover. It is fixed and put into a storage member and assembled. However, the folding capacity of the airbag is different from that immediately after folding and after folding, and the airbag base fabric has no folds immediately after folding, and the folding and repelling of the airbag base fabric makes it difficult to store and assemble It may become.

  Therefore, as an airbag cover for suppressing the folded airbag base fabric, a method of eliminating folding resilience using a woven fabric has been proposed, but the mechanical properties, light weight, and compactness of the used woven fabric are proposed. There is no technical proposal for flame retardancy, and simply attaching the woven fabric as an airbag cover suppresses the repulsion of the airbag base fabric while the airbag is mounted on the vehicle, and is lightweight. It was not enough in terms of having both compactness and compactness. (See Patent Document 1).

In addition, as a wrapping material for airbags, a material using a flame retardant polyester nonwoven fabric obtained by copolymerizing a compound containing phosphorus atoms has been proposed, but this is a proposal limited to the nonwoven fabric and is flame retardant. However, the nonwoven fabric is thicker than the woven fabric, and it is difficult to satisfy the compactness which is important as a wrapping material for airbags (see Patent Document 2).
Japanese Patent Laid-Open No. 10-244895 JP 2004-204408 A

  In view of the drawbacks of the conventional airbag cover, an object of the present invention is to simultaneously combine mechanical characteristics, light weight and compactness, and in addition, an airbag cover excellent in storage assembly workability of an airbag base fabric and its manufacture It is an object to provide a method and an airbag housing member.

The present invention employs the following means in order to solve such problems. That is, the airbag cover of the present invention is a fabric in which the ratio S / t between the tensile strength S (N / mm) and the thickness t (mm) is in the range of 30 to 170 N / mm ² in both the vertical and horizontal directions. It is an airbag cover characterized by comprising.

The airbag cover of the present invention is a fabric in which the ratio S / t between the tensile strength S (N / mm) and the thickness t (mm) is in the range of 60 to 140 N / mm ² in both the vertical and horizontal directions. It is an airbag cover characterized by comprising.

According to a preferred aspect of the airbag cover of the present invention, the fabric weight is in the range of 30 to 120 g / m ² and the fabric thickness t is in the range of 0.05 to 0.15 mm.

  According to a preferred aspect of the airbag cover of the present invention, the tensile strength S in the vertical direction and the horizontal direction of the fabric is in the range of 1 to 70 N / mm, and the vertical and horizontal tearing of the fabric is performed. The strength is in the range of 50-1000N.

  According to a preferred aspect of the airbag cover of the present invention, the yarn constituting the fabric is a polyester fiber, and the fabric is a woven fabric.

  The airbag cover of the present invention can be used as an airbag storage member.

  The method for manufacturing an airbag cover of the present invention is characterized in that at least the following steps are sequentially passed.

First step: Warping using a synthetic fiber having a strength of 4 to 20 cN / dtex and a total fineness of 25 to 200 detex,
Second step: Using the drum obtained after warping, the weft strength is in the range of 4-20 cN / dtex, the total fineness is in the range of 25-200 dtex, and the total length of warp and weft A step of weaving into a plain structure using a synthetic fiber having a fineness difference of 100 dtex or less,
Third step: scouring the obtained woven fabric,
Fourth step: A step of heat-setting the woven fabric subjected to the scouring in the third step.

  According to a preferred aspect of the method for manufacturing an airbag cover of the present invention, the gluing is performed immediately before the first step or within the first step.

According to the present invention, it is possible to provide an airbag cover that has both mechanical characteristics, light weight, and compactness at the same time, and that is excellent in storing and assembling work of the airbag base fabric, and an airbag storage member including the airbag cover. The occupant protection system using the airbag can be promoted.
Further, in the present invention, a material satisfying flame retardancy can be obtained by removing the spinning oil, warp glue, etc. adhering to the obtained woven fabric in the manufacturing process of the airbag cover. .

Next, the best mode of the airbag cover of the present invention will be described. The airbag cover of the present invention is made of a fabric in which the ratio S / t between the tensile strength S (N / mm) and the thickness t (mm) is in the range of 30 to 170 N / mm ² in both the vertical and horizontal directions. This is an airbag cover.

  The fabric used in the present invention is a fiber fabric, and can be preferably composed of synthetic fibers. The synthetic fiber used in the present invention is not particularly limited as long as it is a fiber-forming polymer. Synthetic fibers composed of generally used polyolefin, polyamide, polyester, polyacrylonitrile, or a copolymer thereof. Can be used. Among them, heat resistance or amine resistance so that a vehicle equipped with an air bag can withstand any environment that is normally used on the earth, for example, a high temperature area such as a desert area or an environment where chemicals are loaded and used. A polyester-based synthetic fiber made of polyester excellent in the above or a copolymer thereof is preferably used practically.

  Such synthetic fibers may contain various additives usually used for improving the productivity or properties in the production process and processing process of the raw yarn. For example, a heat stabilizer, an antioxidant, a light stabilizer, a smoothing agent, an antistatic agent, a plasticizer, a thickener, a pigment, a flame retardant, and the like can be contained.

  The airbag cover of the present invention may be a fabric that satisfies mechanical properties such as tensile strength and tear strength as an airbag cover such as a woven fabric and a nonwoven fabric. Among them, a material that is lightweight and compact is preferable, and more preferably, it has flame retardancy. Here, the flame retardancy means that the burning rate is specifically 90 mm / min or less by the method specified in FMVSS302, and the flame retardance is a material that can be used for automobile applications.

The fabric constituting the airbag cover of the present invention has a ratio S / t between the tensile strength S (N / mm) and the fabric thickness t (mm) in order to achieve both mechanical characteristics, light weight, and compactness. (N / mm ²⁾ is, it is necessary that in the longitudinal direction and the transverse direction both in the range of 30~170N / mm ^2, preferably, the ratio ^{S / t (N / mm 2} ) the 60~140N / mm Is within the range of ² .

  When assembling the airbag, it is necessary to have sufficient tensile strength to cover the airbag base fabric folded while pulling the airbag cover in a certain direction, and the assembled and stored airbag must be compact. There is a demand, and not only an airbag base fabric and an inflator but also an airbag cover that is pursuing compactness such as using a thin cover is required. Therefore, by setting the ratio S / t between the tensile strength S and the thickness t within the range specified in the present invention, the airbag cover has superior mechanical properties and is superior to light weight and compactness. It becomes.

When the ratio S / t of the tensile strength S to the thickness t is less than 30 N / mm ² , the tensile strength and thickness cannot satisfy the mechanical characteristics and compactness required for an airbag cover, and the The cover may be torn and the assembled airbag is inferior in compactness. Conversely, if the ratio S / t between the tensile strength S and the fabric thickness t exceeds 170 N / mm ² , the strength of the fabric is high and the cover is difficult to break when the airbag is deployed, and the airbag base fabric is deployed. May interfere. Here, in order to set the ratio S / t between the tensile strength S and the thickness t within the range of 30 to 170 N / mm ² , when the woven fabric is used, the tensile strength S is set to 1 in both the vertical direction and the horizontal direction. It is preferable to weave within a range of 70 N / mm, more preferably within a range of 3 to 20 N / mm, a thickness t within a range of 0.05 to 0.15 mm, and a woven structure as a plain structure. In order to achieve the tensile strength S, it can be achieved by setting the strength of the synthetic fiber to be used within the range of 4 to 20 cN / dtex. The thickness t can be achieved by setting the total fineness of the synthetic fiber to be used within the range of 25 to 200 dtex. When weaving in a plain structure, the synthetic fiber preferably has a total fineness difference of 100 dtex or less between the synthetic fibers used for the warp yarn and the weft yarn, more preferably the synthetic fiber used for the warp yarn and the weft yarn has the same fineness. Is to use things.

The fabric constituting the airbag cover of the present invention preferably has a basis weight in the range of 30 to 120 g / m ² in order to achieve both lightness and mechanical characteristics. If the basis weight is less than 30 g / m ² , the weight of the fabric is excessively light, so that the workability at the time of storing and assembling the airbag base fabric is poor, and the assembly efficiency of the airbag may be deteriorated. On the other hand, if the basis weight is larger than 120 g / m ² , the weight of the airbag cover becomes heavy, and it becomes an unsuitable material for an airbag cover that is required to be lightweight. Here, in order to make the basis weight within the range of 30 to 120 g / m ² , when a woven fabric is used, it can be achieved by weaving so that the weave density becomes the basis weight in a weaving step. For example, by using a synthetic fiber having a total fineness of 150 dtex and weaving the weave density to 89 horizontal and 67 horizontal with a plain structure, the basis weight becomes 112 g / m ² , and the basis weight can be achieved.

  Moreover, the thickness of the fabric used for the airbag cover of the present invention is preferably in the range of 0.05 to 0.15 mm in order to achieve compactness and flame retardancy. If the thickness of the fabric is less than 0.05 mm, it is advantageous in compactness, but the area that comes into contact with the atmosphere with respect to the volume of the fabric itself becomes large, and the flame retardancy necessary for automobile applications may be satisfied. It becomes difficult. On the other hand, if the thickness of the fabric exceeds 0.15 mm, the compactness is disadvantageous and a bulky airbag is obtained. Here, in order to make the thickness t within the range of 0.05 to 0.15 mm, when using a woven fabric, the total fineness of the synthetic fibers used is within the range of 25 to 200 dtex, and weaving into a plain structure. Can be achieved. In the case of weaving in a plain structure, the synthetic fiber preferably has a total fineness difference of 100 dtex or less between the synthetic fibers used for the warp and the weft yarn, more preferably the synthetic fiber used for the warp and the weft yarn has the same fineness. It is to be.

    The fabric constituting the airbag cover of the present invention preferably has a tensile strength in the range of 1 to 70 N / mm in the mechanical properties of the airbag cover. When the tensile strength is less than 1 N / mm, the cover is easily damaged in the operation of covering the folded bag by pulling the cover performed at the time of storing and assembling the airbag base fabric, and holds the folded airbag base fabric. There is a risk that the function cannot be performed. On the other hand, when the tensile strength exceeds 70 N / mm, the fabric is bulky or has a high weight. Here, in order to make the tensile strength S within the range of 1 to 70 N / mm, when the woven fabric is used, the strength of the synthetic fiber used can be achieved within the range of 4 to 20 cN / dtex. .

  In addition to tensile strength, tear strength is an important mechanical property for airbag covers. By setting the tear strength within the range of 50 to 1000 N, a material having more preferable mechanical properties as an airbag cover is obtained. When the tearing strength is lower than 50 N, it is difficult to hold the folded airbag base fabric, and there is a possibility that the airbag base fabric is repelled while the airbag is mounted on the vehicle. On the other hand, when the tear strength is 1000 N or more, the airbag cover is not torn when the airbag is deployed, and the deployment of the airbag is hindered, so that the occupant may not be protected. In order to smoothly deploy the airbag, it is possible to perforate the airbag cover, but it is necessary to make the cut longer, and the airbag base fabric may protrude from the cut. Here, in order to make the tearing strength within the range of 50 to 1000 N, when the woven fabric is used, the strength of the synthetic fiber to be used can be achieved within the range of 4 to 20 cN / dtex.

  The fabric used for the airbag cover of this invention can provide the novel airbag cover which is excellent in a mechanical characteristic surface and a lightweight compact surface as mentioned above by using a woven fabric.

An example of using a non-woven fabric as an airbag cover is disclosed in Japanese Patent Application Laid-Open No. 08-244545. However, when a non-woven fabric is used, the thickness increases in order to satisfy mechanical properties, particularly tensile strength. In many cases, it is difficult for the ratio S / t between the tensile strength S and the thickness t to be in the range of 30 to 170 N / mm ² in both the vertical and horizontal directions. Here, in order for the nonwoven fabric to have a ratio S / t of tensile strength S to thickness t in the range of 30 to 170 N / mm ² in both the vertical direction and the horizontal direction, the Tyvek (TYVEK) with a basis weight of 80 to 120 g / m ² is used. (Registered trademark) can be made within the above range by reducing the thickness t by passing a hot press roller or the like, but it is disadvantageous in terms of cost due to an increase in the number of manufacturing steps.

  Conversely, if the thickness is reduced to satisfy the compact surface, the tensile strength will be reduced, and the cover will be damaged in the operation of covering the folded bag by pulling the cover performed during the storage and assembly of the airbag base fabric. There is a risk that the function of holding the folded airbag base fabric cannot be achieved. Therefore, it is preferable that the fabric satisfying the mechanical characteristics, lightness and compactness required for the airbag cover is a woven fabric.

  Here, the fabric used for the airbag cover is a material advantageous in terms of mechanical characteristics, lightweight and compact, and cost by using polyester synthetic fibers, and in addition, storage and assembly workability of the airbag base fabric. It is possible to provide an airbag cover including the above.

  In addition, the airbag cover of the present invention is used as a storage member for a passenger seat airbag, a curtain airbag, or the like having a large airbag base fabric and a large base fabric repulsion after folding. Can make full use of the mechanical properties, light weight and compactness. In addition, the airbag cover of the present invention, which is superior in terms of light weight and compactness, is used as an airbag storage member for a driver seat airbag, a side airbag, a rear seat airbag, etc. that have a small base fabric repulsion after folding. can do. The air bag cover and the air bag housing member of the present invention are characterized in that they have mechanical characteristics, light weight and compactness at the same time, and in addition, the air bag base fabric is excellent in storing and assembling workability.

  Next, the manufacturing method of the airbag cover of this invention is demonstrated according to process.

[First step: Warping step]
This process is a process in which the warp yarns used for the woven fabric are arranged in a drum-like cylinder with a predetermined number. When the total fineness of the yarn made of the synthetic fiber to be used is in the range of 30 to 200 dtex, it is preferable to apply a paste before or during the warping process. The purpose of applying glue is to cover single yarn breakage, which is a defect of yarn made of synthetic fibers, not only to improve the processability of the next weaving process, but also to adjust the antistatic and texture of the product This is to obtain an effect such as being able to. That is, when the total fineness of the yarns made of synthetic fibers is within the range of 30 to 200 dtex, the obtained woven fabric has a soft texture, but imparting appropriate rigidity by gluing. This makes it possible to improve the storage and assembly workability of the airbag base fabric.

  There are two types of glue used at the time of gluing: a non-aqueous glue and an aqueous glue. Both types of glue can be used, but they are widely used and cost-effective. It is preferable to use a water-based paste that is superior, and more preferable is an acrylic paste or polyvinyl alcohol paste that is most commonly used.

[Second step: Weaving step]
This is a step of weaving a yarn made of synthetic fibers wound around a drum-shaped tube, created in the first step. The synthetic fiber to be used preferably has a total fineness difference between the warp yarn and the weft yarn of 100 dtex or less, and more preferably, the synthetic fiber used for the warp yarn and the weft yarn has the same fineness.

  Any loom such as shuttle loom, water jet loom, air jet loom and rapier loom can be selected as the loom used in the weaving process, but the water jet loom and air jet loom that are advantageous in terms of production speed are selected. It is preferable to do. In addition, the woven structure may be woven into any structure such as a plain structure, an oblique structure, and a satin structure, but preferably woven into a plain structure, and any of the woven fabrics when used as an airbag cover. Even with the use of parts, a material having uniform mechanical properties can be obtained.

[Third step: Scouring step]
It is a step of removing spinning oil, warp yarn glue, etc. adhering to the woven fabric obtained in the second step. If this scouring step is not performed, the oil and paste remaining on the woven fabric will cause The woven fabric is flammable and is an unsuitable material for an airbag cover used for automobile applications. For this reason, the scouring step is an important step for obtaining a material satisfying the flame retardancy while having the mechanical characteristics, light weight and compactness necessary for the airbag cover. The treatment liquid used in this scouring is preferably water or an aqueous solution containing a surfactant and an alkali. The method for performing the scouring is not limited, but is generally an open soap type continuous scouring machine, a liquid flow type dyeing machine, a suspension type continuous processing machine in bath, a wine dyeing machine, and a softer scouring machine, which are generally used for scouring woven fabrics. Etc. are preferable.

[Fourth process: Heat setting process]
The woven fabric after weaving and the woven fabric after scouring tend to collapse in the woven fabric structure and often have non-uniform mechanical properties in the weaving width direction of the woven fabric for use as an airbag cover. It is a material that is inferior in workability because the rigidity of the woven fabric is weak during cloth storage and assembly work. Heat is applied to the woven fabric that has been scoured in the third step to make the woven structure a uniform woven structure, and then heat-fixed to give the woven fabric uniform mechanical properties and appropriate rigidity. Can do. A method for performing the heat setting is not limited, but it is preferable to perform heat treatment using a pin tenter type heat setter that is generally used as a heat treatment machine when processing a woven fabric. At this time, the woven structure can be heat-set by setting the heat treatment temperature within a temperature range of 140 to 200 ° C. In addition, when heat treatment is performed with a pin tenter type heat setter, the texture of the finished woven fabric is adjusted by fixing both ends of the woven fabric with a setting width that is narrower or wider than the woven fabric width after weaving. Thus, the mechanical characteristics, basis weight and texture necessary for the airbag cover can be adjusted.

  The airbag cover manufactured by the above process is cut into a predetermined shape, and is used with a perforated cut at the planned breakage when the airbag is deployed. When the airbag cover of the present invention is cut into a predetermined shape from the base fabric, it is not necessary to limit the weaving direction. More preferably, cutting is performed along the weaving direction of the vertical direction and the horizontal direction so that the perforation can be applied, and further preferably the shape along the direction in which the tear strength of the airbag cover is weak. Then, cut so that it can be perforated.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited to these. In addition, each evaluation in an Example was performed in accordance with the following method.

[Unit weight]
The weight of the fabric of 1 m in length and 1 m in width was measured to determine the basis weight.

[Thickness t]
It calculated | required based on JISL1096 (8.5.1) (1999).

[Tensile strength S]
Based on JIS L1096 (8.12.1A method) (1999), the breaking strength was measured when the woven fabric was pulled at a tension grip distance of 200 mm and a tension speed of 100 mm / min. The measurement result was converted to N / mm.

[Elongation at break]
It calculated | required based on JISL1096 (8.12.1A method) (1999).

[Tearing strength]
Based on JIS L1096 (8.15.2A-2 method) (1999), the tear strength when pulled at a tensile speed of 200 mm / min was determined.

[Flame retardance]
The burning rate from the marked line at 38 mm from the edge of the base fabric was determined by the method prescribed in FMVSS302 (1991) [Ratio of tensile strength S to fabric thickness t S / t]
The tensile strength S (N / mm) was obtained by dividing it by the thickness t (mm).

Example 1
Warp yarn is warped using a 36-round round multifilament filament yarn made of polyethylene terephthalate with a total fineness of 56 dtex and glued with polyvinyl alcohol. Polyethylene terephthalate with a total fineness of 84 dtex is used for the weft yarn. A round cross-section multifilament yarn having 36 single yarns was used as a raw material, and a woven fabric having a warp density of 103 / 25.4 mm and a warp density of 79 / 25.4 mm was woven in a plain weave structure. The obtained woven fabric is de-sanded with a softener scourer, scoured, dried, and set at a temperature of 190 ° C. for 1 minute using a pin tenter. A woven fabric of 25.4 mm was obtained. The obtained woven fabric was measured for basis weight, thickness t, tensile strength S, elongation at break, tear strength and flame resistance test (in accordance with FMVSS 302 method), and the results are shown in Table 1.

As is apparent from Table 1, the obtained woven fabric had a ratio S / t between the tensile strength S and the fabric thickness t in the range of 30 to 170 N / mm ^{2 both in} the vertical direction and in the horizontal direction. It has characteristics, light weight and compactness at the same time. In addition, it has excellent flame retardancy and air bag storage and assembly workability, and also has flame retardance necessary for automobile applications.

  The obtained airbag cover was cut into a predetermined shape, and perforated cuts were made along the weaving direction in the horizontal direction, and the airbag was assembled and assembled. During the operation, the airbag cover was not damaged, and the airbag could be produced. At the time of deployment, the airbag cover was torn along the perforation, and the airbag could be deployed smoothly.

(Example 2)
Warp yarn is warped using a 36-round round multifilament filament yarn made of polyethylene terephthalate with a total fineness of 75 dtex as a raw material and glued with polyvinyl alcohol. Polyethylene terephthalate with a total fineness of 100 dtex Weaving, scouring, and setting in the same manner as in Example 1 using a round cross-section multifilament yarn having 50 single yarns made from the raw material, warp density 107 pieces / 25.4 mm, width density 92 pieces / 25.4 mm A woven fabric was obtained. The obtained woven fabric was evaluated in the same manner as in Example 1, and the results are shown in Table 1. As is apparent from Table 1, the ratio S / t between the tensile strength S and the fabric thickness t is in the range of 30 to 170 N / mm ² in both the vertical and horizontal directions, and mechanical properties, light weight and compactness are achieved. At the same time, in addition, it was excellent in flame retardancy and air bag storage assembly workability, and also had the flame retardance required for automotive applications.

  The obtained airbag cover was cut into a predetermined shape, and a perforated cut was made along the weaving direction in the horizontal direction, and the airbag was assembled and assembled. During the operation, the airbag cover was not damaged, and the airbag could be produced. At the time of deployment, the airbag cover was torn along the perforation, and the airbag could be deployed smoothly.

(Example 3)
Warp using warp yarn made of polyethylene terephthalate with a total fineness of 150 dtex as a raw material and rounded multifilament filament yarn with 30 single yarns and glued with polyvinyl alcohol. Polyethylene terephthalate with a total fineness of 150 dtex Weaving, scouring and setting in the same manner as in Example 1 using a round cross-section multifilament yarn having 30 single yarns made from the raw material, and having a warp density of 89 / 25.4 mm and a horizontal density of 67 / 25.4 mm A woven fabric was obtained. The obtained woven fabric was evaluated in the same manner as in Example 1, and the results are shown in Table 1. As is apparent from Table 1, the ratio S / t between the tensile strength S and the fabric thickness t is in the range of 30 to 170 N / mm ² in both the vertical and horizontal directions, and mechanical properties, light weight and compactness are achieved. At the same time, it has excellent air bag storage and assembly workability, and also has flame retardancy required for automotive applications.

  The obtained airbag cover was cut into a predetermined shape, and perforated cuts were made along the weaving direction in the horizontal direction, and the airbag was assembled and assembled. During the operation, the airbag cover was not damaged, and the airbag could be produced. At the time of deployment, the airbag cover was torn along the perforation, and the airbag could be deployed smoothly.

(Comparative Example 1)
The warp and weft yarns were woven with a warp and weft density of 46 / 25.4 mm without applying a gluing step to the round cross-section filament yarn of nylon 66 having a total fineness of 470 dtex and 72 single yarns. The obtained woven fabric was scoured, dried, and set at a temperature of 180 ° C. for 1 minute using a pin tenter to obtain a woven fabric having a vertical and horizontal density of 46 / 25.4 mm. As apparent from Table 1, the ratio S / t with the resulting fabric tensile strength S and the fabric thickness t exceeds 170N / mm ^2, a thickness even exceed 0.15 mm, the even basis weight 120 g / m ^Since it exceeded ² , it became a material which has excessive mechanical characteristics as an airbag cover and lacks compactness and lightness.

(Comparative Example 2)
A “TYVEK” (registered trademark) nonwoven fabric manufactured by DUPONT having a basis weight of 55 g / m ² was used as the fabric.
As is clear from Table 1, Tyvek is used as an airbag cover because the ratio S / t between the tensile strength S and the fabric thickness t is less than 30 N / mm ² and the thickness exceeds 0.15 mm. The material lacks mechanical properties and compactness.

(Comparative Example 3)
Aramid fibers having a total fineness of 1110 dtex (trade name: “Kevlar” (registered trademark, manufactured by DuPont) are used for warp and weft yarns, with a flat structure having a warp density of 31 / 25.4 mm and a weft density of 31/25. The woven fabric was woven so as to be 4 mm. As is apparent from Table 1, the obtained woven fabric was a material having a high tensile strength, with the ratio S / t of the tensile strength S to the fabric thickness t being 280 N / mm ² or more. As for the tear strength, since the woven fabric structure itself was disassembled when a tensile load of 1350 N was applied without being torn, it was determined that the tear strength was 1350 N or more and the woven fabric was used as an airbag cover. Sometimes it was not torn and became a material that could interfere with airbag deployment.

The airbag cover of the present invention has mechanical characteristics, light weight and compactness at the same time. In addition, the airbag cover is excellent in the storage and assembly workability of the airbag base fabric, and can spread and promote the passenger protection system using the airbag. Useful.

Claims (11)

An airbag cover comprising a fabric in which a ratio S / t between a tensile strength S (N / mm) and a thickness t (mm) is in a range of 30 to 170 N / mm ² in both the vertical direction and the horizontal direction. . An airbag cover comprising a fabric in which the ratio S / t of the tensile strength S (N / mm) to the thickness t (mm) is in the range of 60 to 140 N / mm ² in both the vertical and horizontal directions. . Claim 1 or 2 airbag cover according basis weight of the fabric is being in the range of 30 to 120 g / ^{m 2.}   The airbag cover according to any one of claims 1 to 3, wherein a thickness t of the fabric is in a range of 0.05 to 0.15 mm.   The airbag cover according to any one of claims 1 to 4, wherein the tensile strength S in the vertical direction and the horizontal direction of the fabric is in the range of 1 to 70 N / mm.   The airbag cover according to any one of claims 1 to 5, wherein the tear strength in the vertical direction and the horizontal direction of the fabric is within a range of 50 to 1000N.   The airbag cover according to any one of claims 1 to 6, wherein the yarn constituting the fabric is made of a polyester fiber.   The airbag cover according to any one of claims 1 to 7, wherein the fabric is a woven fabric.   The airbag storage member formed using the airbag cover in any one of Claims 1-8. A method for manufacturing an airbag cover, comprising sequentially passing through at least the following steps.
1st process: The process which warps using the synthetic fiber whose intensity | strength is in the range of 4-20 cN / dtex, and the total fineness is in the range of 25-200 detex,
Second step: Using the drum obtained after warping, the weft strength is in the range of 4-20 cN / dtex, the total fineness is in the range of 25-200 dtex, and the total length of warp and weft A step of weaving into a plain structure using a synthetic fiber having a fineness difference of 100 dtex or less,
Third step: scouring the obtained woven fabric,
Fourth step: A step of heat-setting the woven fabric subjected to the scouring in the third step.   The method for manufacturing an airbag cover according to claim 10, wherein the airbag base fabric is stored and glued immediately before the first stroke or in the first stroke to improve storage and assembly workability of the airbag base fabric according to claim 10. .