JP2002363836A - Base fabric for non-coated air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a base fabric having the same mechanical characteristics as those of a conventional base fabric and substantially sufficient air impermeability and flame retardance as a base fabric for an air bag. SOLUTION: This fabric for a non-coated air bag is characterized in that the fabric is a high-density woven fabric having >=2,000 cover factor and <0.5 cc/cm<2> /sec quantity of airflow, an oil content attached to the high-density woven fabric is <0.1 wt.%, a tensile strength (S) is S>=160 kg/3 cm (JIS K6328 5.3.5) and an elongation at break (E) is 15<=E<=35% (JIS K5328 5.3.5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base fabric for a non-coated airbag, and more particularly, to a non-coated airbag which is lightweight, flexible, excellent in storage, and excellent in air permeability and flame retardancy. It is related to the base fabric.

[0002]

2. Description of the Related Art In recent years, mounting of airbags as an occupant protection and safety device for automobiles has been rapidly progressing. Since the airbag is usually stored in a narrow place such as a steering wheel or an instrument panel, reducing the storage volume is one of required performances.

[0003] Therefore, efforts have been made in the past for fabrics for airbags to be as foldable as possible and to minimize the storage volume as far as the mechanical properties are satisfied. For example, in the case of rubber-coated base cloth, the transition of coated rubber from polychloroprene-based rubber to silicone-based rubber is progressing. This is because the use of silicone-based rubber can reduce the amount of applied rubber coat and provide a flexible rubber-coated base cloth. Is completed.

On the other hand, in order to ensure the safety of the occupants of the automobile, it is desired to increase the mounting rate of the airbag. One of the driving forces is to reduce the price of the entire airbag system. This is one of the required performances for airbags. Therefore, further reduction in the price of the airbag base fabric has been taken up as an issue, and development of a non-coated base fabric that has a high possibility of cost reduction is being promoted.

[0005] The non-coated base fabric is also advantageous in terms of softness, storability, and light weight of the base fabric for airbags, and there is a need for early establishment of technology as a base fabric for next-generation airbags.

[0006] As a proposed technique relating to a conventional non-coated airbag fabric, for example, Japanese Unexamined Patent Publication No. Hei 3-137245 is disclosed.
JP, JP-A-64-70247 and JP-A-Heisei 3
The thing described in -134245 gazette etc. is known.

In other words, the technology described in Japanese Patent Application Laid-Open No. 1-122752 discloses a high-density woven fabric in order to control gas permeability, which is an important characteristic of a non-coated airbag base fabric. It discloses a base fabric for a non-coated airbag manufactured by applying a fixed calendering process or the like.

The technique described in Japanese Patent Application Laid-Open No. 64-70247 discloses that a base fabric having a basis weight of 250 g / m ² or less is calendered so that the air permeability is 5 cc / c.
An object of the present invention is to disclose a base fabric for a non-coated airbag of m ² / sec or less.

Further, the technique described in Japanese Patent Application Laid-Open No. 3-134245 discloses a non-coated base fabric made of a symmetrically structured woven fabric subjected to calendar processing, having a fineness of 300 to 400 dtex and made of a high shrinkage yarn. It is.

[0010]

However, the above prior arts are all non-coated airbag base fabrics that are lightweight, flexible, have excellent storage properties, and sufficiently satisfy mechanical properties and non-breathability. However, it cannot be said that heat resistance and cost reduction, which are important as the performance of the base fabric for non-coated airbags, are not considered, and further improvements in these heat resistance and cost reduction are desired. Was something.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the prior art, and has the same light weight, flexibility, storability, mechanical properties and non-breathability as a non-coated airbag base fabric. In addition to satisfying the above requirements, the base for non-coated airbags made of woven fabrics in a water jet loom (hereinafter referred to as WJL) with excellent weaving efficiency in order to achieve even higher flame retardancy and lower cost. The purpose is to provide cloth.

[0012]

Means for Solving the Problems In order to achieve the above object, the non-coated airbag fabric of the present invention has a cover factor of 2000 or more and a ventilation rate of 0.5 cc / cm ^2.
/ Sec, the oil content adhering to the high-density fabric is less than 0.1% by weight, and the tensile strength (S) is S ≧ 160 kg / 3cm (JIS K63
28 5.3.5), and the elongation at break (E) is 15 ≦ E ≦ 35
% (JIS K6328 5.3.5).

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The non-coated airbag fabric of the present invention is characterized in that the high-density fabric is made of nylon 66, nylon 6, nylon 46 or polyethylene terephthalate fibers.

The fibers used in the non-coated airbag fabric of the present invention are nylon 66, nylon 6, nylon 46 and polyethylene terephthalate fibers. Usually, fibers composed of a single polymer are preferred, but
It may contain 10% by weight or less of a copolymer component. In particular, in the case of nylon 46 fiber, since it is difficult to produce a homopolymer because of its high melting point and high crystallinity, a fiber containing about 5% by weight of a copolymer component is more preferable.

[0015] The fibers used in the present invention have the mechanical properties of a phosphorus-coated airbag base fabric, that is, the strength of the base fabric that can withstand the instantaneous expansion of gas, especially impact strength, burst strength, tear strength, and the like. 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 airbag hits the occupant, for example, in the case of nylon 66, nylon 6, and nylon 46 fibers, the relative viscosity of sulfuric acid is used. A polymer having an (ηr) of 3.0 or more and a polyethylene terephthalate having an intrinsic viscosity ([η]) of 0.8 or more is desirably used.

Further, the base fabric for a non-coated airbag according to the present invention is intended to prevent heat history during the production of the yarn, and to prevent heat deterioration, light deterioration, oxidation deterioration and hydrolysis during storage and use as a product. In the case of nylon 66, nylon 6, and nylon 46 fibers, an antioxidant is preferably contained.

As an antioxidant, an inorganic or organic copper acid such as copper iodide, copper bromide, copper chloride, copper acetate, copper pyrophosphate, copper stearate, etc. is added in an amount of 10 to 3000 ppm, preferably 20 to 150 ppm as copper. And alkali metal halides such as potassium iodide, potassium bromide, potassium chloride, sodium iodide, sodium bromide, sodium chloride, lithium iodide, lithium bromide and lithium chloride;
Alternatively, 0.05 to 0.5% by weight of an earth metal halide or a quaternary ammonium halide salt may be used in combination. If necessary, an organic or inorganic phosphorus compound is added in an amount of 10 to 500 ppm as phosphorus.

In the case of polyethylene terephthalate fiber, the carboxyl terminal group is set to 30 eq / 10 6 or less, preferably 20 eq / 10 6 in order to prevent hydrolysis.
It is preferable to set the following. Polyethylene terephthalate fibers having a small number of carboxyl end groups can be obtained by employing a low-temperature polymerization method, or by adding a terminal blocking agent such as an epoxy compound, a carbodiimide compound and an oxazoline compound in the spinning step.

The fineness of the fiber used in the present invention is usually 6
It is not more than 00 denier, preferably not more than 500 denier. This is because the WJL suitable for weaving the base fabric for a non-coated airbag of the present invention is specified as a fineness capable of weaving efficiently.

The base fabric for a non-coated airbag of the present invention comprises:
It is made of a high-density woven fabric having a woven fabric cover factor of 2,000 or more, preferably 2,100 or more, in order to make its air permeability 0.5 cc / cm ² / sec or less.

The cover factor referred to in the present invention is a value obtained by the following equation from the product of the fabric density and the square root of the fineness of the fiber yarn. K = Nw × Dw1 ^{/ 2} + NF × DF1 ^{/ 2} Nw: warp density (lines / inch) Dw: warp denier NF: weft density (lines / inch) DF: weft denier.

It is important that the base material for a non-coated airbag of the present invention contains less than 0.1% by weight of an oil agent. In general, the oil agent for synthetic fibers has a lower ignition point and a lower ignition point than the synthetic fiber itself. Therefore, if the residual oil agent of 0.1% by weight or more adheres, the flame retardancy of the non-coated base fabric cannot be secured. is there.

In particular, since the base fabric for a non-coated airbag of the present invention is a high-density woven fabric in which the air permeability is kept to a certain value or less as described above, once the woven fabric is woven with the oil agent attached, the oil agent in the woven fabric is removed. However, even after the subsequent scouring step, it cannot be sufficiently washed and removed. Therefore, it is preferable that the base fabric for a non-coated airbag of the present invention is woven with WJL which can wash an oil agent during weaving. It is also important to select an oil agent adhering to the yarn that is easily washed during WJL weaving.

The oil agent applied to the non-coated airbag base fabric of the present invention is required to have a low friction between the yarn and the metal roll and a small yarn so that the yarn can be formed with less yarn breakage and fluff. The friction between the yarn and the yarn is such that the oil film when the metal and the metal come into contact with high tension is sufficiently strong, the oil agent deposited on the heating roll is less likely to be thermally oxidized and decomposed, and the interlace for bundling the filament is likely to occur. It has characteristics such as being moderately high and being easy to wash in the WJL weaving process.

The following oil agent is applied to the non-coated airbag fabric of the present invention as an oil agent satisfying the above conditions.

That is, a divalent fatty acid ester compound (A) containing 20 to 50% by weight of ethylene oxide having a molecular weight of 600 to 1000, a polyether polymer activator (B) having a molecular weight of 1000 to 5000, and a molecular weight of 60
A polyalkylene glycol (hereinafter abbreviated as PEG) ester compound (C) containing 25 to 55% by weight of 0 to 1000 diethylene oxide;
Is a mixture obtained by mixing 50 to 65% by weight of (B), 5 to 5% by weight of (B), and 20 to 40% by weight of (C).

More specifically, the divalent ester compound (A) contains 20 to 50% by weight of ethylene oxide having a molecular weight of 600 to 10000, and specifically includes dioctyl alcohol EO ₃ adipate and dilauryl alcohol EO ₃ adipate. And adipates such as oleyl alcohol EO ₃ adipate, and thiodipropionates such as sebacate, dioctyl alcohol EO ₃ thiodipropionate and dioleyl alcohol EO ₃ thiodipropionate.

The polyether polymer activator (B) is
Molecular weight of 1000-5000, preferably 2000-3
000, for example, a non-ionic activator obtained by reacting a monocarboxylic acid and / or a dicarboxylic acid with a compound selected from a higher alcohol alkylene oxide adduct and a polyhydric alcohol alkylene oxide adduct.

The above-mentioned alkylene oxide adduct of polyhydric alcohol is, for example, a product obtained by adding an alkylene oxide such as ethylene oxide, propylene oxide, or butylene oxide to a polyhydric alcohol, such as the addition of ethylene oxide to hydrogenated castor oil. Products, castor oil ethylene oxide adducts, sorbitol ethylene oxide adducts, and trimethylolpropane ethylene oxide adducts. Above all, hydrogenated castor oil ethylene oxide adduct, sorbitol ethylene oxide adduct or higher alcohol alkylene oxide adduct is preferred.

Further, specific examples of the above-mentioned monocarboxylic acids include caproic acid, caprelic acid, lauric acid, palmitic acid, stearic acid, oleic acid and isostearic acid, and preferably palmitic acid, stearic acid, oleic acid and the like. And isostearic acid.

Specific examples of the above dicarboxylic acids include maleic acid, adipic acid, thiodipropionic acid, sebacic acid, dodecanoic acid and brassic acid.
Of these, maleic acid, adipic acid and propionic acid are preferred.

The PEG ester compound (C) has a molecular weight of 600 to 1,000, and as the monocarboxylic acid esterified with diethylene glycol, caproic acid, caprelic acid, lauric acid, palmitic acid, stearic acid,
Oleic acid and isostearic acid and the like are preferable, and preferable are palmitic acid, stearic acid, oleic acid and isostearic acid.

The mixing ratio of the dihydric fatty acid ester compound (A), polyether polymer activator (B), and PEG ester compound (C), which are the oil components according to the present invention, depends on the yarn production yield and the generation of fluff. It has important effects on quantity, warping and weaving process passability, and fabric quality.

Next, a method of manufacturing the base fabric for a non-coated airbag of the present invention will be described. The raw yarn of the base fabric for a non-coated airbag of the present invention is produced by melt spinning a polyamide such as nylon 66, nylon 46 or nylon 6 and a polyethylene terephthalate polymer.

In the melt-spinning step, the polymer is melt-spun, and the oil agent is applied to the cooled and solidified yarn. The oil component is usually applied as a solution diluted with low molecular weight mineral oil or water. Oil adhesion to fiber is 0.3 ~
It is 1.5% by weight, usually 0.5-1.0% by weight.

The yarn to which the oil agent has been applied is preferably sent to a stretching step continuously and subjected to a stretching heat treatment. For the stretching, a multi-stage thermal stretching method of usually two or more stages is employed. The drawn yarn is heat-set and wound up, but immediately before winding, the yarn is interlaced to bundle the filaments together. Interlacing is performed by blowing a high-pressure fluid, for example, high-pressure air or steam, from the outer periphery of the yarn through a nozzle.

A part of the raw yarn produced by the above method is sent to a warping step, and is turned back into a warping beam for warp.
Some are prepared as wefts and woven in WJL.

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

WJL is efficiently woven at a weft driving speed of about 1000 m / min or more, preferably 1200 m / min or more. Usually, most of the oil agent adhering to the yarn is washed away during this weaving, and the residual oil content is less than 0.1% by weight. Since the oil agent applied to the yarn according to the present invention is composed of the above-mentioned specific oil agent component, it is easily washed and removed by water during weaving of WJL, has a low hydrolytic viscosity, and does not generate scum or the like.

The woven greige is usually sent to a heat setting step without heat through a scouring step and heat set. In the heat setting step, one side or both sides may be calendered in order to control air permeability as a non-coated airbag base fabric, or to control feeling and flexibility.

The airbag fabric of the present invention produced by the above method has the following fabric properties. (1) Cover factor (K) K ≧ 2000 (2) Tensile strength (S) S ≧ 160 kg / 3cm (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 permeability (P) P ≦ 0.5 cc / cm 2 / sec (JIS L1096 6.27A) (6) Flammability (B) B ≦ 50 mm / min (FMVSS No. 302).

The base fabric for a non-coated airbag of the present invention having such properties is lightweight, flexible, excellent in storage properties and mechanical properties, and has practically sufficient non-breathability and flame retardancy.

In particular, as compared with a conventional chloroprene rubber-coated and silicone rubber-coated airbag base fabric, it is advantageous in terms of lightness, flexibility and storability, but has the advantage that it can be manufactured at lower cost.

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

[0045]

Next, embodiments of the present invention will be specifically described with reference to examples. Examples 1 to 3 Relative viscosity of sulfuric acid (sample concentration 1% by weight, 25 ° C) was 3.5.
100 ppm of phosphorus and 80 pp of copper as antioxidants
and nylon 66 chips containing 0.1% by weight of m and potassium iodide were melted by an extruder spinning machine.
After the molten polymer was filtered in a spin pack, it was spun out from the die pores. The die used had 72 holes with 0.25 mm diameter pores. The spun yarn was cooled and solidified by cold air after passing through the slow cooling zone immediately below the spinneret.

Next, 55 parts by weight of dioctyl alcohol EO ₂ ADJET was added to the above-mentioned yarn, and hydrogenated castor oil E
OA molecular weight 2000 thiodipropionate 10
A mixture obtained by mixing 30 parts by weight of PEG 200diolate and 30 parts by weight of PEG 200 (hereinafter referred to as "oil No. 1") was applied with an oil diluted to 20% by weight with a higher hydrocarbon having C13 carbon atoms. Withdrawn at a speed of 900 m / min.

Subsequently, the same oil agent as described above was applied as it was while stretching the yarn by 5% between the take-up roll and the yarn supply roll. The oil agent was applied so as to be about 1% by weight based on the original yarn, but about 0.2% by weight before the take-up roll, and the rest was applied between the take-up roll and the yarn supply roll.

Next, the above-mentioned yarn was sent to a stretching step and stretched continuously. The stretching heat treatment was performed by a one-stage relaxation treatment after performing two-stage thermal stretching. The take-up roll was not heated, the yarn supply roll was 60 ° C., the first stretch roll temperature was 120 ° C., and the second stretch roll temperature was 240 ° C. The relaxation roll after stretching is 12
0 ° C.

Further, between the take-up roll and the yarn supply roll,
While stretching by 5%, about 1% of a mixed non-aqueous oil agent comprising a smoothing agent, an activator and a small amount of an extreme pressure agent, an additive such as an antistatic agent and an antioxidant is adhered to the drawn fiber. As given. The stretching ratio is 3.56 for the first step.
The second stage was 1.25, and the relaxation rate was 8%. Immediately before winding, the interlace was wound so that the number of confounds was about 40 per m.

The raw yarn obtained by the above method is 420D-
At 72 fill, the strength was 9.6 g / d, the elongation was 22%, the boiling water shrinkage was 6.0%, and the number of fluff was 2.2 per 10 million m. A part of this raw yarn was used as a warping beam having 2100 warp yarns. The weaving was performed using WJL manufactured by Tsuda Koma Co., Ltd. at a weft driving speed of 1000 m / min. The greige was heat-set at 180 ° C. without going through a scouring step to obtain a non-coated airbag fabric (Example-
1). Further, by changing the weaving conditions as shown in Table 1, two more types of non-coated airbag fabrics were obtained (Examples-2 and -3). Table 2 shows the results of evaluating the performance of each of the obtained non-coated airbag base fabrics as an airbag base fabric.

Comparative Examples 1 to 4 When the weaving conditions of Example 1 were changed as shown in Table 1 (Comparative Example 1), the original yarn was formed in the same manner as in Example 2;
When the loom type was changed to rapier (Comparative Example-2), the oil component of Example-2 was obtained by adding 60 parts by weight of dioleyl adipate, 20 parts by weight of sorbitol EOA molecular weight 850,
And PEG 200 diolate: a mixture of 20 parts by weight (oil agent No. 2) and a warping oil agent added in the warping step (Comparative Example-3)
Table 2 also shows the results of evaluating the properties of the respective airbag base fabrics obtained when the same oil agent as in Comparative Example 3 was used and woven on a rapier loom (Comparative Example 4).

In Example 3, Comparative Example 2 and Comparative Example 3, a scouring step was performed to remove oil. In addition, scouring was performed by passing through a 70 ° C. warm bath containing a scouring agent for 2 minutes.

[0053]

[Table 1]

[0054]

[Table 2]

As is clear from the results shown in Tables 1 and 2, in the case of a high-density woven fabric having an air permeability of less than 0.5 cc / cm ² / sec, the oil agent specified in the present invention is applied and WJ
Only when woven with L, the residual oil agent is 0.1% by weight or less, and a non-coated airbag base fabric having excellent flame retardancy is obtained.

[0056]

As described above, the non-coated airbag fabric of the present invention has the same mechanical properties as the conventional polychloroprene rubber-coated fabric and silicone rubber-coated fabric, and has the same characteristics as the airbag fabric. Since it has practically sufficient non-breathability and flame retardancy as a base cloth, it can be preferably used instead of a conventional rubber-coated base cloth.

The base fabric for a non-coated airbag of the present invention comprises:
Compared to conventional rubber-coated base fabrics, it is lightweight, flexible, and excellent in terms of storability. It is woven with efficient WJL and does not require a rubber coat. Having. That is, the base fabric for a non-coated airbag of the present invention is advantageous in terms of both the above excellent performance and low manufacturing cost, and thus suitably contributes to an improvement in the airbag mounting rate desired for protecting occupants of automobiles. can do.

Continued on the front page F term (reference) 3D054 CC25 CC26 4L048 AA21 AA24 AA33 AA34 AA48 AA49 AA50 AB07 AC09 AC10 AC11 CA11 CA15 DA25 EA01

Claims (2)

[Claims] 1. A high-density woven fabric having a cover factor of 2,000 or more and an air permeability of less than 0.5 cc / cm ² / sec, wherein the oil content adhering to the high-density woven fabric is 0.1% by weight.
And tensile strength (S) is S ≧ 160 kg / 3
cm (JIS K6328 5.3.5) and elongation at break (E) 15 ≦ E ≦ 35% (JIS K6328 5.3.5).
3.5) The base fabric for a non-coated airbag, which is characterized in that: 2. The airbag fabric according to claim 1, wherein the high-density fabric is made of nylon 66, nylon 6, nylon 46 or polyethylene terephthalate fiber.