JPH08325888A - Non-coated air bag and fabric therefor - Google Patents

Abstract

PURPOSE: To obtain both a fabric for a non-coated air bag, having low gas permeability even without carrying out the resin coating and excellent in mechanical strength and compactness and an air bag capable of performing compact housing thereof and retaining the characteristics of the fabric and hardly shocking a human body in inflation. CONSTITUTION: This base fabric for a non-coated air bag is obtained by mixing a thermoplastic synthetic fiber yarn A having 1.5 to 7.0 denier single filament size with a thermoplastic synthetic fiber yarn B having 0.2 to 1.5 denier single filament size at (80:20) to (30:70) ratio A:B of the numbers of the single filaments and weaving the resultant mixed yarn having 200-500 Denier total size and >=8.0g/d strength as warp and/or weft yarns. Synthetic fibers constituting the mixed yarn preferably comprise polyester fibers, especially polyethylene terephthalate fibers. The air bag is prepared by using the fabric for the non- coated air bag having the characteristics as a material according to a means such as sewing and has <=0.5cc/cm<2> /sec amount of air permeation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-coated fabric for an airbag and an airbag which are used without being coated with a resin. The present invention also relates to a cloth for an uncoated airbag which is excellent in compactness, and an airbag which retains the characteristics of the cloth and has a small impact on a human body when inflated and can be compactly stored.

[0002]

2. Description of the Related Art Airbags as a safety device for protecting occupants of automobiles have been remarkably spread in recent years.

The required performances for airbag fabrics are, first of all, that they have a low gas permeability that allows them to expand smoothly upon impact, and that they have sufficient mechanical strength to withstand impacts. There are things like that.

Secondly, the human body, especially the face part, is not damaged during the inflation when it is inflated, it can be stored compactly, and there is no dimensional change during installation on the vehicle body for a long period of time. To be

However, the fact is that a fabric for airbags satisfying all the above requirements has not been developed so far.

That is, for example, if it is attempted to suppress the gas permeability of an airbag, the fabric becomes thick and lacks compactness, and there is a tendency that the impact when it comes into contact with a human body becomes large, and so on. Conflicting properties are required in fabric design.

As a typical airbag fabric that has been developed to date, for example, a single yarn fineness of 4 to 7d and a total fineness of 400 described in JP-A-3-243442.
A cloth made of nylon thread of D to 1000D and a cloth (hereinafter referred to as a coated product) coated with a resin such as chloroprene or silicon are known.

[0008] However, the above-mentioned nylon cloth for air bags is excellent in suppressing gas permeability, but since the cloth is thick, the air bag using this cloth is inferior in compactness. In addition, since all the yarns are made of nylon yarn, there is a problem that the dimensional stability is also poor.

Further, in the case of the coated product, the manufacturing process is complicated, so that the manufacturing cost is high and it is difficult to apply a uniform resin coating.

Various proposals have been made in order to solve the above problems, for example, JP-A-1-10484.
As described in Japanese Patent Publication No. 8, there is an attempt to reduce the total fineness of the yarns constituting the cloth to reduce the thickness of the cloth, to make the cloth soft and to impart compactness.

However, simply reducing the total fineness significantly increases the gas permeability, and as a result, resin coating becomes essential and compactness is not satisfied.

In addition, in order to improve low gas permeability and compactness, attempts have been made to reduce not only the total fineness of the yarn but also the single yarn fineness at the same time, and further weaving the woven fabric at a higher density. However, as a result, a material that can satisfy the low gas permeability and mechanical strength has not been obtained yet.

For example, in JP-A-64-41438, emphasis is placed on the foldability of an airbag, and the strength is 8.5 g /
A fabric for an air bag is described which is composed of fibers having a diameter of d or more and a single yarn fineness of 3 d or less, but in this case also, in order to reduce the gas permeability, a total fineness of 400D to 1000D is required, and as a result, Since the amount of yarn used is large, compactness cannot be sufficiently improved.

Further, in Japanese Patent Laid-Open No. 4-2835,
A cloth for non-coated airbags formed by using polyethylene terephthalate fibers has been proposed, and it has been reported that this cloth is lightweight and thin, but as the fibers to be used, thick yarns with a total fineness of 400D to 1000D are used. Therefore, the flexibility of the fabric has not been sufficiently improved, and calendering is required on both sides in order to reduce gas permeability. There was a problem that became very complicated.

The calendering also causes a decrease in the mechanical strength of the cloth, and above all, there is a problem that the manufacturing cost becomes very high.

[0016]

SUMMARY OF THE INVENTION The present invention has been achieved as a result of studying how to solve the above-mentioned problems in the prior art.

Therefore, an object of the present invention is to provide a cloth for an uncoated airbag which has a low gas permeability, is excellent in mechanical strength and compactness without applying a resin coating, and retains the characteristics of the cloth and is expanded. An object of the present invention is to provide an airbag that can be stored compactly with less impact on the human body.

[0018]

In order to achieve the above object, a non-coated airbag base fabric of the present invention comprises a thermoplastic synthetic fiber yarn A having a single yarn fineness of 1.5d to 7.0d.
The thermoplastic synthetic fiber yarn B having a single yarn fineness of 0.2d to 1.5d is mixed at a single yarn number ratio (A: B) = 80: 20 to 30:70, and the total fineness is 200D
It is characterized in that a mixed yarn having a strength of 8.0 g / d or more and a strength of 8.0 g / d or more is used for the warp and / or the weft and is woven.

The synthetic fibers constituting the mixed yarn are preferably polyester fibers, especially polyethylene terephthalate fibers.

The airbag of the present invention is made of the non-coated airbag base fabric having the above-mentioned characteristics as a material, and is made by sewing or the like.
It is characterized by being 5 cc / cm ² / sec or less.

The most significant feature of the present invention is that the multifilament yarns constituting the non-coated airbag fabric are high-strength yarns A with a fineness, particularly polyester yarns A, and yarns B with a finer yarn than this. Particularly high strength polyester yarn B
It consists of a mixed yarn with.

Thus, the fineness yarn A (hereinafter referred to as the single yarn A
In contrast to this, a mixed yarn in which a yarn B having a fineness smaller than that of the single yarn A (hereinafter referred to as a single yarn B) is mixed is used as a warp yarn and / or a weft yarn to achieve high density. By weaving, the gas permeability is suppressed to a low level without impairing the mechanical strength, flexibility and compactness required for airbags, and for non-coated airbags that have all the characteristics preferable for airbag fabrics. A base cloth is obtained.

The mixed yarn is a yarn in which the single yarn A and the single yarn B are mixed and arranged without being unevenly distributed in the cross section of the multifilament yarn, and the single yarn A and the single yarn B are arranged. It is desirable that they are mixed as uniformly as possible.

If the single yarn fineness and the constituent single yarn number ratio are within the specific ranges of the present invention, the single yarn A is surrounded by the single yarn B.
On the other hand, on the contrary, the single yarn B is likely to be surrounded by the single yarn A, so that the closest packing arrangement is easily formed as a whole.

As a result, when the cloth is formed, the single yarns A and B in the cloth cross section are extremely uniformly arranged without a gap, so that the gas permeability is suppressed to a low level.

In the mixed yarn according to the present invention, one multifilament yarn constituting the warp and / or the weft of the fabric is composed of a plurality of yarns having different fineness,
The single yarns A and B must be mixed.

The single yarn finenesses of the single yarn A and the single yarn B in the mixed yarn are within the range of 1.5d to 7.0d and within the range of 0.2d to 1.5d, respectively, and the single yarn A is Is required to have a thicker single yarn fineness than the single yarn B, and the ratio of the number of constituent single yarns is A: B = 80: 20 to 30: 7.
A range of 0 is required, especially 70:30 to 40:60
Is preferred. The single yarn fineness ratio (A / B) between the single yarn A and the single yarn B is preferably 3 or more.

If the single yarn fineness of the single yarn A and the single yarn B deviates from the above range, it becomes difficult to arrange the single yarns A and B in the closest packing arrangement, and the gas permeability can be suppressed low. It will be difficult. Further, when the mixing ratio of the single yarns A and B is out of the above range, the effect as a mixed yarn becomes small.

In the mixed yarn according to the present invention, it is preferable that the difference in fineness between the single yarns A and B constituting the mixed yarn is large within a range in which the strength of the yarn is not affected and both finenesses are as small as possible. Since the arrangement is more likely to be the closest packing, it is effective to take the above single yarn fineness condition.

The finer the single yarn fineness, the better the softness of the fabric and the more compact the fabric becomes. However, if it is too thin, the strength of the yarn is lowered and the mechanical strength of the fabric is affected. The single yarn fineness of the yarn B needs to be 0.2 d or more.

On the other hand, if the single yarn fineness is too large, the fabric becomes inferior in flexibility and compactness.
The single yarn fineness of the single yarn A needs to be 7.0d or less.

When a general single yarn is arranged in the closest packing arrangement, the gas permeability is suppressed to a low level, but on the other hand, there is a concern that the flexibility of the fabric may be affected. By adjusting the fineness of the single yarn, it is possible to increase the degree of freedom of the single yarn while maintaining the closest packing arrangement, so that low gas permeability can be achieved without hindering the flexibility.

For example, a mixed yarn having an initial modulus as low as possible and having necessary strength and elongation may be used, and / or the composition ratio of the activator in the treated oil agent provided during the yarn making may be increased. By reducing the coefficient of static friction (μs) between the yarns, the flexibility of each single yarn in the yarn at the time of forming the fabric is further improved, and the fabric having more preferable flexibility can be obtained.

Generally, it is difficult to suppress the gas permeability to be low in the woven fabric obtained by weaving such low-definition yarns. However, in the airbag fabric according to the present invention, the woven fabric is used. By making the density high within the range where flexibility is not hindered, the gas permeability is suppressed to a sufficiently low level.

In the present invention, the above-mentioned single yarn A and single yarn B
As the synthetic fiber yarn forming the fiber, known fibers can be used, and polyester fibers such as polyethylene terephthalate fiber and polybutylene terephthalate fiber are preferably used, but polyarylate fiber and the like can also be used.

Further, the polyester fiber may contain a copolymerization component as long as its properties are not impaired.

The above-mentioned mixed yarn can be manufactured by a known method.

For example, a method in which two types of separately produced single yarns having different finenesses are wound and then combined to form one multifilament yarn, separately melt-spun and drawn single yarn A method in which two types of yarns with different fineness are combined before winding to obtain one multifilament yarn, and pores with different pore diameters An example of such a method is a fiber mixing method during spinning, in which a mixed yarn composed of two types of single yarns having different fineness is melt-spun and stretched at the same time by using a spinneret in which holes are arranged in a closest packing manner.

However, since simultaneous spinning and drawing of two types of single yarns having different fineness requires a relatively high technique,
A method is preferred in which two types of yarns having different single-fiber finenesses, which are separately produced in advance, are combined and the yarns which are entangled by air or steam are used.

The cloth for an uncoated airbag according to the present invention is required to have a mechanical strength sufficient to withstand the impact during expansion.

Tensile strength showing mechanical strength as a cloth,
Tear strength, burst strength, breaking elongation, etc. are also affected by woven density, etc., but in the non-coated airbag fabric of the present invention, since the multifilament yarn having a relatively small total fineness is used, the fabric is Becomes thin, and the influence of the strength of the mixed yarns constituting the yarn becomes large.

Therefore, the mixed yarn constituting the airbag fabric of the present invention must have a tensile strength of 8.0 g / d or more.

The intrinsic viscosity IV of the polyester mixed yarn constituting the airbag fabric of the present invention is 0.8 or more,
More preferably, by setting it to 0.85 or more, the durability of the airbag is improved, and in combination with the strength of the above yarn, the shock absorbing property when the airbag is momentarily inflated is further improved. be able to.

The total fineness of the mixed yarn in the present invention is 200 D or more and 500 D or less, particularly 210 D in order to reduce the thickness of the fabric and to exhibit compactness and flexibility.
It must be in the range of D or more and 420D or less.

When the total fineness of the mixed yarn exceeds 500D,
The gas permeability of the cloth will be governed by the thickness, and the lightness, compactness and flexibility which are the effects of the present invention will decrease, and when weaving the cloth, for example, a water jet room (hereinafter, (WJL) and the like are unsuitable because there is a high risk of impairing process passability.

On the other hand, if the total fineness of the mixed yarn is less than 200D, the fabric is too thin, and although the yarn has a high strength, it has a mechanical strength sufficient to withstand the impact during expansion. It is inappropriate because it will be insufficient.

Therefore, in the non-coated airbag fabric according to the present invention, it is necessary to use a multifilament yarn having a total fineness of 200D to 500D in order to achieve flexibility, compactness and lightness.

As described above, in the non-coated airbag fabric of the present invention, the yarns constituting the fabric have a single yarn fineness of 1.
Single yarn A of 5d to 7.0d and single yarn B of single yarn fineness of 0.2d to 1.5d are A: B = 80: 20 to 30:
A mixed yarn having a single yarn number ratio of 70, a total fineness of 200 D to 500 D, and a tensile strength of 8.0 g / d or more satisfying low gas permeability as a non-coated airbag fabric, It has excellent effects on lightness, compactness, flexibility and shock absorption.

The non-coated airbag fabric of the present invention is
The mixed yarns can be obtained by a known weaving method, but when the mixed yarns are all the warp / weft yarns of the fabric, the gas permeation suppressing effect of the fabric is most remarkably exhibited. .

However, even when the above-mentioned mixed yarn is used for one of the warp yarn and the weft yarn, the air flow rate can be suppressed sufficiently low.

The airbag fabric according to the present invention is
It is preferable to perform shrinkage treatment if necessary. This shrinking treatment can be performed by dry heat treatment, wet heat treatment or solvent treatment.

The base fabric for a non-coated airbag of the present invention is an efficient water jet loom (WJL).
Weaving in, and does not require calendar processing,
Enables significant cost reduction.

Further, since the calendering can be omitted, the fibers constituting the fabric are not deteriorated by the calendering, and as a result, the mechanical strength such as tear strength of the fabric can be prevented from lowering.

The airbag of the present invention is obtained by stitching the above-mentioned base fabric for non-coated airbag by means of a known sewing means, and in particular, has an air flow rate of 0.5 c.
c / cm ² / sec or less, preferably 0.3 cc / cm
^It has a low gas permeability of ² / sec or less.

Then, in the airbag of the present invention,
The fact that the non-coated cloth woven using the above-mentioned mixed yarn constitutes the entire surface of the airbag leads to more preferable results in terms of both lightweight and compactness.

Further, the airbag of the present invention has the same structure as that of the present invention even when the fabric made of the above-mentioned mixed yarn is used at least on the side which comes into contact with the human body when the airbag is inflated. The effect can be sufficiently expressed.

In this case, a thick cloth is used in a place near the inflator where heat resistance is more required, to the extent that the overall compactness and flexibility are not impaired.
It does not matter at all that a low-density portion for intentionally deflating the airbag after inflation is provided on a part of the fabric that does not come into contact with the human body.

Further, when stitching into an air bag shape, it is of course possible to apply a reinforcing cloth or tape to this stitching portion.

That is, if a cloth made of the above-mentioned mixed yarn is used at least on the side that comes into contact with the human body, the impact on the human body can be made sufficiently small.

The air bag of the present invention having the above-mentioned constitution retains the characteristics of the above-mentioned non-coated air bag fabric that it has a low gas permeability and is excellent in mechanical strength and compactness, and at the same time, it can be inflated to the human body during inflation. It has little impact and can be stored compactly.

The air bag of the present invention having the above merits can be adopted in both the driver's seat and the passenger's seat.

[0062]

EXAMPLES The constitution and effects of the present invention will be further described below with reference to examples.

Each physical property in the examples was measured as follows.

(1) Intrinsic viscosity IV: Using an Ostwald viscometer, to 100 ml of orthochlorophenol,
The relative viscosity η _rp of the solution in which 3 g of the sample was dissolved was measured at 25 ° C. and converted into IV.

(2) Weave density: JIS-L-1096
It measured according to (6.6).

(3) Thickness: JIS-L-1096
It measured according to (6.5).

(4) Rigidity: JIS-L-1096
It was measured according to (6.19.1A).

(5) Tear strength: JIS-L-1096
It was measured according to (6.15.4C).

(6) Air permeation amount: JIS-L-1096
Measurement was performed according to (6.27.1 A), and the amount of passing air was shown in CC / cm ² / sec.

(7) Compactness: The fabrics of the same area were folded up the same number of times and the bulkiness was compared.

[Examples 1 to 6, Comparative Examples 1 to 7] Polyethylene terephthalate chips having an intrinsic viscosity (IV) of 1.23 were melted in an extruder type spinning machine under nitrogen gas substitution,
Subsequently, the molten polymer was filtered in a spinning pack equipped with a spinneret having a pore size and a pore number according to the purpose for obtaining a desired fiber, and then spun from the spinneret pores.

The spun yarn passed through a slow cooling zone immediately below the spinneret, was then cooled and solidified by cold air, was given a treatment oil agent, was sent to a stretching step, and was continuously stretched and relaxed, and then wound.

In the above method, the spinner used is changed to obtain filament yarns having different single yarn finenesses as shown in Tables 1 and 2, and each one of these filament yarns is used in Tables 1 and 2. A mixed yarn was obtained by combining yarns so that the total fineness, the total number of single yarns, and the ratio of the number of single yarns shown in 2 were obtained, interlaced through a compressed air nozzle, and then wound up.

The characteristics of the mixed yarns obtained by the above method are shown in Tables 1 and 2.

Next, the mixed yarn obtained by the above method was woven into a cloth according to the following method.

That is, a part of the drawn yarn is 210
WJL made by Tsuda Koma Co., Ltd. as 0 warping beam
Was used at a weft driving speed of 1000 m / min.

The raw cloth was heat-set at 180 ° C. under a constant tension as it was without undergoing a scouring step, to obtain a cloth for a non-coated airbag.

The characteristics of the respective fabrics obtained by the above method and the characteristics of the airbag manufactured by the usual method using this cloth are as shown in Tables 1 and 2.

For easy comparison, the woven densities of the respective fabrics were made uniform.

The compactness evaluation criteria in Tables 1 and 2 are as follows. ◎ …… Highly preferred (especially good ones are ◎
◎, and ◎◎◎. ) ○ …… favorable △ …… not very favorable × …… not favorable

[0081]

[Table 1]

[0082]

[Table 2]

As is clear from Table 1, the fabrics for non-coated airbags of the examples according to the present invention have low gas permeability,
It was excellent in both durability and compactness, and was well balanced as a fabric for airbags.

On the other hand, in Comparative Examples 1 and 4, since the mixed yarn is not used, the air permeation amount is not suppressed.

In Comparative Examples 2 and 3, although the mixed yarns are used, the air permeation amount is not suppressed because the number of single yarns of different fineness single yarns to be mixed is not appropriate, and it is required as a fabric for an airbag. It is not preferable in terms of mechanical strength.

In Comparative Example 5, the mixed yarn is used, but the air permeation amount is not suppressed because the fineness balance of the single yarns of different fineness to be mixed is not appropriate, and further the fineness of the single yarn A is too large. The fabric is hard and unfavorable in terms of compactness.

In Comparative Example 6 as well, although the mixed yarn is used, the air permeation amount is not suppressed because the fineness balance of the single yarns of different fineness to be mixed is not proper, and the fineness of the single yarn B is too small. However, the mechanical strength of the fabric is not preferable.

Further, Comparative Example 7 uses a mixed yarn and is excellent in mechanical strength, but it is inferior in compactness above all because of the high fineness yarn, and the process at the time of weaving It is also not preferable in terms of passage property.

Comparative Example 6 also uses mixed yarns and is very excellent in compactness, but since it is a fine yarn, it has poor mechanical strength and is not preferable as a fabric for airbags. .

[0090]

EFFECT OF THE INVENTION The cloth for non-coated airbag according to the present invention has mechanical strength equivalent to that of the conventional coating cloth, has low gas permeability practically sufficient as a cloth for airbag, and is flexible. It has improved flexibility, compactness and lightness. In addition, weaving in an efficient water jet loom (WJL) does not require calendering, which enables a significant cost reduction.

Further, since the calendering can be omitted, the fibers constituting the cloth are not deteriorated by the calendering, and as a result, the mechanical strength such as tear strength of the cloth can be prevented from deteriorating.

Further, the air bag of the present invention retains the characteristics of the above-mentioned non-coated air bag fabric having low gas permeability and excellent mechanical strength and compactness, and has less impact on the human body when inflated. It can be stored compactly.

Claims (5)

[Claims] 1. A thermoplastic synthetic fiber yarn A having a single yarn fineness of 1.5d to 7.0d and a single yarn fineness of 0.2d to 1.5.
7. The thermoplastic synthetic fiber yarn B of d is mixed at a single yarn number ratio (A: B) = 80: 20 to 30:70, and the total fineness is 200D to 500D and the strength is 8.
A fabric for a non-coated airbag, which is formed by using a mixed yarn of 0 g / d or more as a warp yarn and / or a weft yarn. 2. A single yarn fineness ratio (A / B) of a thermoplastic synthetic fiber yarn A and a thermoplastic synthetic fiber yarn B constituting a mixed yarn.
The cloth for an uncoated airbag according to claim 1, wherein the number is 3 or more. 3. The non-coated airbag fabric according to claim 1, wherein the synthetic fibers constituting the mixed yarn are polyester fibers. 4. An airbag using the cloth for an uncoated airbag according to claim 1, 2 or 3 as a base fabric material. 5. An air flow rate of 0.5 cc / cm ² / sec
The airbag according to claim 4, wherein: