JPH0790747A - Base fabric for non-coat air bag - Google Patents

Abstract

PURPOSE:To provide a non-coat base fabric for air bag, a high-density woven fabric excellent in lightness, flexibility and storability, and improved in mechanical properties represented by esp. tear strength, air permeability and flame retardancy, woven with a water jet loom of high weaving efficiency. CONSTITUTION:The objective base fabric for non-coat air bag consisting of low air-permeable high-density woven fabric >=2000 in cover factor and < 0.5 cc/cm<2>/sec in air permeability, has the following characteristics: (1) the respective warp and weft synthetic fiber filament yarns making up the fabric are interlaced so as to have interlacing points at intervals of 10 50 mm in water; (2) oil pickup: < 0.1wt.%; (3) comprised of fibers selected from nylon 66, nylon 6, nylon 46 and polyethylene terephthalate; and (4) the fineness of the filament yarn making up the fabric: <=500 denier and that of the single fiber: <=4 denier.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-coated airbag base fabric, and more specifically, it is excellent in lightness, flexibility and storability and has improved mechanical properties, breathability and flame retardancy. The present invention relates to a non-coated airbag base fabric.

[0002]

2. Description of the Related Art In recent years, an airbag has been rapidly installed as a vehicle occupant protection safety device.

Since an airbag is usually stored in a narrow space such as a steering wheel and an instrument panel, it is required to reduce the storage volume.

Therefore, the required performance of the airbag base cloth is that it has the best foldability and excellent storability as far as the mechanical properties are satisfied. Efforts have been made in the past to minimize the storage capacity of airbags.

For example, in rubber-coated base fabrics, the shift from polychloroprene to silicone-based rubbers is progressing. This is because the use of silicone-based rubbers makes it possible to reduce the coating amount of the rubber coat and to provide a flexible rubber-coated substrate. Because you can make a cloth.

Further, recently, development of a non-coated base fabric for an airbag which does not use any rubber coat has been underway. That is, since the non-coated base fabric for an airbag is most advantageous in terms of flexibility, storability and lightness,
It is highly expected that it will be put into practical use as a base fabric for next-generation airbags.

[0007] The problem of the non-coated base fabric for an air bag is to keep the characteristics such as flexibility, storability and light weight as mentioned above, while practically using the low air permeability and flame retardancy which are the characteristics of the rubber coated base fabric. It is to improve to a satisfactory level.

From this point of view, many proposals have been made regarding the non-coated airbag base fabric, and typical conventional techniques include, for example, JP-A-4-2835 and JP-A-3-134245. Kaihei 1-122
752 and Japanese Patent Laid-Open No. 64-70247 and the like.

That is, the technique disclosed in Japanese Patent Laid-Open No. 4-2835 discloses a low air-permeable non-coated airbag base fabric obtained by calendering a polyester fiber woven fabric and a method for producing the same.

Further, the technique described in Japanese Patent Laid-Open No. 3-134245 discloses a non-coated base fabric made of a woven fabric having a symmetric structure subjected to calendering and having a fineness of 300 to 400 dtex and a high shrinkage yarn. .

Further, in the technique described in Japanese Patent Laid-Open No. 122752/1989, in order to control gas permeability which is an important property as a base fabric for a non-coated airbag, the base fabric itself is a high density fabric, and further, Disclosed is a base fabric for a non-coated airbag produced by applying shrinkage processing, heat-setting calendering processing, or the like.

Furthermore, in the technique disclosed in Japanese Patent Laid-Open No. 64-70247, the breathability is increased to 5 cc by calendering a base fabric having a basis weight of 250 g / m ² or less.
Disclosed is a non-coated base fabric for an airbag, which is not more than / cm ² / sec.

The uncoated airbag base fabrics described in the above publications are lighter in weight, more flexible, and easier to store than the conventional airbag coated base fabrics coated with chloroprene rubber or silicone rubber. It has been shown that it has excellent properties and that it has practically satisfactory mechanical properties and low air permeability.

By the way, in order to obtain a non-airbag base fabric having the above-mentioned characteristics, it is most advantageous to form a high-density fabric by using fibers having a fine single yarn fineness.
Such fabrics have the drawback of low tear strength,
The reality is that improvements in this respect are eagerly desired.

However, none of the above-mentioned prior arts discloses or suggests that the tear strength of a high-density woven fabric composed of fibers having the above-mentioned thin single yarn fineness is improved.

[0016]

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the above-mentioned conventional techniques.

Therefore, an object of the present invention is to provide a high-density woven fabric which is excellent in lightness, flexibility and storability and has improved mechanical properties such as tear strength, breathability and flame retardancy. And to provide a non-coated airbag base fabric woven by a water jet loom (hereinafter referred to as WJL) having excellent weaving efficiency.

The inventors of the present invention have conducted extensive studies in order to achieve the above object. As a result, even a non-coated base fabric for an air bag made of a high-density woven fabric using fine-definition yarn has a predetermined fiber content. Use the interlaced,
Further, they have found that a base fabric for a non-coated airbag satisfying the above-mentioned desired performances can be obtained by controlling the amount of the oil agent adhered to the fabric within a specific range, and thus arrived at the present invention.

[0019]

That is, the non-coated airbag base fabric of the present invention has a cover factor of 200.
A base fabric for a non-coated airbag, which is made of a low-breathing high-density woven fabric having a ventilation amount of 0 or more and less than 0.5 cc / cm ² / sec, wherein each synthetic fiber yarn of the background constituting the woven fabric comprises:
Both are interlaced in water so as to have entangled portions at intervals of 10 to 50 mm, and the oil content attached to the woven fabric is less than 0.1% by weight.

The base fabric for a non-coated airbag of the present invention is characterized in that the high-density fabric is made of fibers selected from nylon 66, nylon 6, nylon 46 and polyethylene terephthalate.

Further, in the base fabric for a non-coated airbag of the present invention, the fineness of the fiber yarns constituting the high density fabric is 500.
It is characterized in that it is denier or less and the fineness of the single yarn is 4 denier or less.

The base fabric for a non-coated airbag of the present invention is
It has excellent properties such as lightness, flexibility and storability, and improved mechanical properties such as tear strength, breathability and flame retardancy. It is characterized in that a predetermined interlace is applied and the amount of the oil agent adhered to the fabric is regulated within a specific range.

The fibers used in the non-coated airbag base fabric of the present invention are fibers selected from nylon 66, nylon 6, nylon 46 and polyethylene terephthalate. For these fibers, it is usually preferable to use fibers each composed of a single polymer, but 10% by weight is preferable.
The following copolymer components may be included. Especially nylon 4
In the case of 6 fibers, since it is difficult to form a yarn with a homopolymer as it is because of its high melting point and high crystallinity, a copolymerized polyamide fiber containing about 5% by weight of a copolymerization component, for example, ε-caprolactam is rather preferable.

The hollow cross-section fiber according to the present invention has a mechanical property of the base cloth, that is, strength of the base cloth capable of withstanding instantaneous expansion of gas, particularly impact strength, burst strength, tear strength, etc., and expanded airbag. It is necessary to use a polymer having a high degree of polymerization in order to satisfy the energy for absorbing the impact when the vehicle hits the occupant. Specifically, nylon 6
6, nylon 6, and nylon 46 fibers require a relative sulfuric acid viscosity (ηr) of 3.0 or more, and polyethylene terephthalate require an intrinsic viscosity ([η]) of 0.8 or more.

The base fabric for a non-coated airbag according to the present invention is made of nylon for the purpose of preventing heat history during yarn production, heat deterioration during storage and use as a product, light deterioration and oxidative deterioration. For 66, Nylon 6 and Nylon 46 fibers it is preferred to include an antioxidant. As antioxidants, inorganic and organic acid copper such as copper iodide, copper bromide, copper chloride, copper acetate, copper pyrophosphate, and copper stearate is added as copper in an amount of 10 to 300 ppm, preferably 20 to 150 ppm. Potassium bromide, potassium bromide, potassium chloride, sodium iodide, sodium bromide, sodium chloride, lithium iodide, lithium bromide,
It is desirable to contain an alkali metal halide such as lithium chloride, an earth metal halide, or a quaternary ammonium halide salt in an amount of 0.05 to 0.5% by weight. If necessary, an organic or inorganic phosphorus compound may be contained as phosphorus in an amount of 10 to 500 ppm.

In the case of polyethylene terephthalate fiber, the carboxyl end group concentration is 30 eq / 10 ⁶ or less, preferably 20 eq / 10 for the purpose of preventing hydrolysis.
It is preferably ⁶ or less. The polyethylene terephthalate fiber having a small number of carboxyl terminal groups can be obtained by adopting a low temperature polymerization method, adding an epoxy compound, a carbodiimide compound, an oxazoline compound or the like as a terminal blocking agent in the spinning step.

The fineness of the fibers constituting the base cloth for an uncoated airbag according to the present invention is usually 500 denier or less, and this fineness is WJL suitable for weaving the base cloth for an uncoated airbag according to the present invention, and the weaving is efficient. It corresponds to the maximum fineness that can be achieved.

On the other hand, the finer the fineness, the more advantageous it is in terms of lightness, flexibility and storability, but the lower limit is preferably 210 denier in order to make the mechanical properties of the base fabric practically satisfactory. .

Further, the single yarn fineness of the fibers constituting the base fabric for a non-coated airbag according to the present invention is 4 denier or less,
It is preferably 3 denier or less. The finer the single yarn fineness is, the softer and compact the air bag base fabric is, which is preferable.

Further, when the single yarn fineness is 4 denier or less, the iterace between the single yarns is likely to be firmly applied, and the interlace is retained even after the weaving. It has the feature that it has higher tear strength than the air bag base fabric.

However, when the single yarn fineness exceeds 4 denier, the effects of the present invention, especially the flexibility and storability of the airbag base fabric are not sufficiently improved, and it is so strong that a high degree of interlace remains after WJL weaving. It is not preferable because it becomes difficult to perform the interlace treatment.

The base fabric for a non-coated airbag of the present invention is a low-permeability woven fabric having an air permeability of 0.5 cc / cm ² / sec or less and a high density woven fabric having a cover factor of 2000 or more, preferably 2100 or more.

Here, the cover factor (K) is a value obtained by the following formula from the product of the fabric constituent density and the square root of the fineness of the fiber yarn. K = Nw × Dw ^1/2 + NF × DF ^1/2 where Nw: warp density (threads / inch) Dw: warp denier NF: weft density (threads / inch) DF: weft denier.

Each of the synthetic fiber yarns forming the base fabric for a non-coated airbag of the present invention is 10 to 10 in water.
It is characterized in that it is interlaced so as to have entangled portions at intervals of 50 mm.

That is, when the base fabric woven fabric according to the present invention is decomposed into warp and weft yarns and immersed in water, 1
The interlace remains so as to have entangled portions with a spacing of 0 to 50 mm.

Generally, as the fineness of the single yarn of the yarn becomes thinner, the tearing strength of the fabric decreases, and as the amount of oil adhered to the fabric decreases and the friction between the warp and weft yarns increases, the tearing strength of the fabric increases. Will fall.

Therefore, in order to prevent such a reduction in tear strength, it is effective to make the interlace relatively strong and converge the filaments constituting the yarn.

In order to ensure that sufficient interlace remains even after weaving with WJL as in the base fabric for an uncoated airbag of the present invention, a relatively strong interlace is applied to the yarn before weaving. It is necessary to put
A yarn that is interlaced with a CF value of 40 or more is used.

However, in the conventional uncoated airbag base fabric woven by WJL characterized by the residual oil content being less than 1% by weight, the yarn obtained by decomposing the base fabric into warp and weft yarns is submerged in water. When soaked, no interlace remained so that the repeat interval could be clearly measured.

Further, the base fabric for a non-coated airbag of the present invention is characterized in that the residual oil content of the oil agent adheres to less than 0.1% by weight.

In general, the oiling agent for synthetic fiber has a lower ignition point and ignition point than the synthetic fiber itself. Therefore, when the residual oiling agent of 0.1% by weight or more is attached, it is difficult to prepare the base fabric for a non-coated airbag. It may not be possible to ensure sufficient flammability.

On the other hand, since the non-coated airbag of the present invention is a high-density fabric whose breathability is kept below a certain value as described above, once the fabric is woven with the oil agent attached, the oil agent in the fabric is However, it cannot be sufficiently washed and removed even after the subsequent refining step.

Therefore, the non-airbag base fabric of the present invention substantially means that the base fabric is woven with WJL, which can wash the oil agent during weaving.

Further, the oil agent attached to the yarn is WJL
It is important to choose one that is easy to wash well during weaving.

As the performance required for the oil agent used in the base fabric for non-coated airbags according to the present invention, the friction between the yarn and the metal roll is small so that the yarn can be produced with less breakage and fluff, and The oil film is sufficiently strong against the extreme pressure when the yarn and the metal come into contact with each other under high tension, and the oil agent deposited on the heating roll is unlikely to undergo thermal oxidative decomposition.
It has moderately high friction between yarns so that interlacing for focusing the filaments is likely to occur, and that it is easy to wash in the WJL weaving process, and these properties are balanced. is necessary.

As an oil agent satisfying the above performance, one comprising a smoothing agent component, an activator component, and a trace amount of an additive agent such as an extreme pressure agent, an antistatic agent and an antioxidant is used, and a preferable oil agent composition As a specific example of "molecular weight 60
20 to 50% by weight of 0 to 1000 ester oxides
Divalent fatty acid ester compound (A) contained, having a molecular weight of 1
2,000 to 5,000 polyester-based activator (B), and diethylene oxide having a molecular weight of 600 to 1,000 by 2
5 to 55% by weight of a mixture of polyethylene glycol ester compound (C) ”.

Next, the method for producing the base fabric for a non-coated airbag of the present invention will be outlined below.

The raw yarn for the base fabric for non-coated airbag of the present invention is produced by melt spinning drawing of polyamide such as nylon 66, nylon 46, nylon 6 or polyethylene terephthalate polymer.

In order to satisfy the mechanical properties of the base fabric, it is preferable that the above-mentioned raw yarn is produced by using a polymer having a high degree of polymerization, such as nylon 66, nylon 6 and nylon 46.
In the case of, the relative viscosity of sulfuric acid (ηr) is 3.0 or more, and in the case of polyethylene terephthalate, the intrinsic viscosity ([η]) is 0.
It is desirable to use 8 or more polymers.

The base fabric for non-coated airbags according to the present invention is made of nylon for the purpose of preventing heat history during yarn production and heat deterioration, light deterioration and oxidative deterioration during storage and use as a product. For 66, Nylon 6 and Nylon 46 fibers it is preferred to include an antioxidant.

Meanwhile, in the case of polyethylene terephthalate fibers, for the purpose of preventing hydrolysis and aminolysis, etc., the carboxyl end group 30 eq / 10 ⁶ or less, preferably to 20 eq / 10 ⁶ or less.

In the spinning step, the polymer is melt-spun, and the cooled and solidified yarn is provided with an oil agent.

The oil agent is applied as a solution obtained by diluting the above oil agent components with low molecular weight mineral oil or water, and the amount of the oil agent attached to the fibers is 0.3 to 1.5% by weight, usually 0.5 to 1.0. % By weight.

The yarn provided with the above-mentioned oil agent is usually continuously sent to a drawing step and subjected to a drawing heat treatment. For the stretching, a multi-stage hot stretching method with two or more stages is usually adopted. The drawn yarn is heat set and wound up, but immediately before winding up, the yarn is interlaced to bundle the filaments together.

The interlacing is performed by spraying a high-pressure fluid such as high-pressure air or steam from the outer circumference of the yarn through a nozzle.

A part of the raw yarn produced by the above method is sent to the warping step and rewound into a warping beam for warp,
A part of the yarn is prepared as weft and woven with WJL.

The base fabric for a non-coated airbag of the present invention is
So that the air flow rate is less than 0.5 CC / cm ² / sec,
A high-density woven fabric with a cover factor of 2000 or more.
For example, when weaving a plain weave using 420 denier nylon 66 raw yarn, the number of warp yarns and weft yarns is 50 or more per inch. More preferably, it is a high-density woven fabric with a cover factor of 2100 or more.

WJL is efficiently woven at a weft driving speed of about 800 m / min or more, preferably 1000 m / min or more. Usually, most of the oil agent attached to the raw yarn is washed away during this weaving, and the residual oil content is less than 0.1% by weight.

The woven raw material is sent to the heat setting step as it is without heat treatment, and heat set.

In this heat setting step, one or both sides may be calendered in order to control the air permeability of the non-coated airbag base fabric, or to control the feel and flexibility.

The base fabric for a non-coated airbag of the present invention produced by the above method has the following excellent physical properties.

(1) Cover factor (K) K ≧ 2000 (2) Tensile strength (S) S ≧ 160 kg / 3 cm (JIS K6328 5.3.5) (3) Elongation at break (E) 15 ≦ E ≧ 35 % (JIS K6328 5.3.5) (4) Tear strength (TS) TS ≧ 15 kg (JIS K6328 5.3.6) (5) Air flow rate (P) P ≦ 0.5 cc / cm ² / sec (JIS L1096 6.27A method) (6) Combustibility (B) B ≦ 50 mm / min (FMVSS No. 302).

The base fabric for a non-coated air bag of the present invention having such characteristics is lightweight, flexible, has excellent storability and mechanical properties, and has practically sufficient performance in terms of non-breathability and flame retardancy.

In particular, compared with the conventional chloroprene rubber-coated and silicone rubber-coated base fabric, it is advantageous in terms of light weight, flexibility and storability, but it also has an advantage that it can be manufactured at low cost.

The base fabric for a non-coated air bag of the present invention having the above advantages can be used for both the driver's seat and the passenger's seat.

Next, one embodiment of the present invention will be specifically shown by the following examples.

[Example] Relative viscosity of sulfuric acid (sample concentration: 1% by weight, 25 ° C) was 3.5, and phosphorus was 100 as an antioxidant.
ppm, copper 80 ppm, and potassium iodide 0.1
Nylon 66 chips containing wt% were melted in an extruder type spinning machine.

The molten polymer was filtered through a spinning pack and spun through the spinneret pores. As the die, ones each having a diameter of 0.25 mm and having various numbers of holes were used.

The spun yarn passed through the slow cooling zone immediately below the spinneret and was then cooled and solidified with cold air. Then, after applying an oil agent diluted to 20% by weight with a higher hydrocarbon to the yarn, it was taken up by a take-up roll at a speed of 900 m / min.

Then, while applying a 5% stretch to the yarn between the take-up roll and the yarn supplying roll, the same oil agent as the above was applied as the undiluted solution.

The oil agent used here is a mixed non-aqueous oil agent comprising a smoothing agent component, an activator component, and a trace amount of additives such as an extreme pressure agent, an antistatic agent and an antioxidant.

The oil content is 0.5 with respect to the fiber wound after stretching.
-1.5 wt%, preferably 0.6-1.2 wt%, about 0.2-0.5 wt% before the take-up roll, the rest is applied between the take-up roll and the yarn feeding roll did.

Next, the yarn was sent to the drawing process and continuously drawn. The stretching heat treatment was performed by a one-step relaxation treatment method after two-step hot stretching.

That is, the take-up roll is not heated, the yarn feeding roll is 60 ° C., the first drawing roll temperature is 120 ° C., the second drawing roll temperature is 240 ° C., and the relaxing roll after drawing is 120 ° C.
℃ was made.

The stretching ratio was 3.56 times for the first step and 1.25 times for the second step, and the relaxation rate in the relaxation treatment was 8%.

The yarn immediately before winding was interlaced so that the number of entangled portions was 0 to 80 per 1 m, and then wound.

By the above-mentioned method, raw yarns having various properties such as raw material polymer, fineness, number of filaments, and single yarn fineness as shown in Table 1 (Examples) and Table 2 (Comparative Examples) were obtained, and their characteristics were obtained. Are also shown in Tables 1 and 2.

[0078]

[Table 1]

[Table 2] Next, a raw fabric was woven using these raw yarns. That is, a warp beam is used as a part of the raw yarn, and WJL made by Tsuda Koma Co., Ltd. is used as a part of the weft yarn.
It was woven at a speed of 1 / min to make a raw fabric.

Then, in this case, the density of the warp and weave fabrics, the cover factor, the type of the loom, and the presence or absence of calendering were changed as shown in Table 3 (Examples) and Table 4 (Comparative Examples) to obtain various raw fabrics.

In Comparative Example 3 shown in Table 4,
The same raw yarn was used for weaving on a rapier loom, and then a scouring process was performed to remove the oil agent, thereby obtaining a raw fabric. The scouring in this case was carried out by passing through a hot bath containing a scouring agent at 70 ° C. for 2 minutes.

Then, each raw machine was heat set at 180 ° C. to obtain a base fabric for a non-coated airbag.

Tables 3 and 4 also show the results of evaluating various properties of each of the obtained base fabrics as an air bag base fabric.

[0083]

[Table 3]

[Table 4] As is clear from the results of Tables 3 and 4, it is a high-density woven fabric with a cover factor (2000 or more) and an air flow rate (less than 0.5 cc / cm ² / sec) specified in the present invention, and has low adhesion. Base fabric for an uncoated airbag of the present invention satisfying the condition of oil content (0.1% by weight or less) (Example 1)
5) are compared with the airbag base fabric for comparison (Comparative Examples 1 to 4) which does not satisfy some or all of these conditions,
It has all the properties such as low air permeability, flame retardancy, flexibility and mechanical properties, especially tear strength.

The warp and weft yarns constituting the woven fabric of the present invention are interlaced even in water (10 to 8).
It can be seen that the condition is 0 / m), the fineness is 500 denier or less, and the single yarn fineness is 4 dale or less.

[0085]

EFFECTS OF THE INVENTION The base fabric for a non-coated airbag of the present invention has mechanical properties equivalent to those of the conventional polychloroprene rubber-coated base fabric and silicone rubber-coated base fabric, and is practically sufficient as an airbag base fabric. Since it has excellent low air permeability and flame retardancy, it can be used in place of the rubber-coated base fabric.

The base fabric for a non-coated airbag according to the present invention is superior in lightness, flexibility and storability to the conventional rubber-coated base fabric. , Fineness less than 500 denier, 4
Despite being composed of single yarn fineness less than denier,
It has a significantly improved tear strength.

Further, the base fabric for a non-coated airbag of the present invention is woven by efficient WJL, and since it does not require a rubber coat, it has a merit that the base fabric manufacturing cost is low. .

Therefore, the non-coated airbag base fabric of the present invention is advantageous in both the above-mentioned performance and manufacturing cost, and thus contributes largely to the improvement of the airbag wearing rate which is desired for protecting the occupants of the automobile. it can.

Claims (3)

[Claims] 1. A base fabric for a non-coated airbag, which comprises a low-breathing high-density woven fabric having a cover factor of 2000 or more and an air permeability of less than 0.5 cc / cm ² / sec, wherein each of the processes constituting the woven fabric A non-coated airbag in which both fiber yarns are interlaced in water so as to have entangled portions at intervals of 10 to 50 mm, and the oil content attached to the woven fabric is less than 0.1% by weight. Base cloth. 2. The base fabric for an uncoated airbag according to claim 1, wherein the high-density woven fabric comprises a fiber selected from nylon 66, nylon 6, nylon 46, and polyethylene terephthalate. 3. The non-coated airbag base according to claim 1, wherein the fineness of the fiber yarn constituting the high-density fabric is 500 denier or less, and the fineness of the single yarn is 4 denier or less. cloth.