JP3467775B2 - Method for producing non-coated airbag fabric - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a fabric for an airbag, which is one of safety devices for automobiles, and more specifically, while maintaining necessary mechanical properties,
It is intended to provide a method for producing a fabric for an airbag for obtaining a fabric for a non-coated airbag, which is characterized by being compact and having a low air permeability and being excellent in economical efficiency.

[0002]

2. Description of the Related Art In recent years, airbags, which have been rapidly improved in wearing rate as one of automobile safety parts, generate a high temperature and high pressure gas from an inflator when a sensor detects an impact in the event of a vehicle collision. This gas prevents the airbag from being rapidly expanded and prevents the driver's or passenger's body, especially the head, from jumping out and colliding with the steering wheel, windshield, door glass, etc. Conventionally, the coated base cloth coated with synthetic rubber such as chloroprene, chlorosulfonated olefin, and silicone is used for airbags because of its high heat resistance, air barrier property (low air permeability), and high flame retardance. Had been used.

However, these coated base fabrics have a high base fabric weight and are not satisfactory in flexibility,
Since the manufacturing cost is high and it is not recyclable,
There were many problems in using it as a base fabric for airbags.

Silicone-coated base fabrics, which are still partially used at present, have been able to solve the above-mentioned problems, but they are not yet satisfactory.

Therefore, recently, a non-coated airbag using a non-coated base fabric for an un-coated airbag has become mainstream, and the following proposals have been made to reduce the weight, improve the storability and reduce the air permeability. Has been done.

1) A method for obtaining a lightweight, low-permeability base fabric by shrinking and calendering after weaving a high-density fabric (JP-A-1-122275). 2) A method in which a lightweight and low-permeability base fabric having a differential pressure of 124 Pa and a low air permeability of 0.5 cc / cm2 / s or less can be obtained by double-sided calendering (JP-A-4-2835). 3) A method of swelling the yarns constituting the cloth to obtain a low-permeability base cloth by subjecting the cloth to chemical shrinkage treatment (JP-A-6-41844). 4) Thermoplastic synthetic fiber A having a single yarn fineness of 1.5d to 7.0d
And a thermoplastic synthetic fiber B of 0.2d to 1.5d are mixed (JP-A-8-325888).

However, in response to the demand for lighter and more compact vehicles, even non-coated airbags are required to be lighter and more compact, but have a low basis weight, excellent compactness, and low air permeability, To produce an economical airbag fabric, for example, even if the air permeability is low under a low differential pressure condition, the air permeability becomes high as a result of a change in the pore size at a high differential pressure.
It cannot be achieved by the conventional methods 1) to 4).

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to produce a fabric for an air bag for obtaining a fabric for an air bag which has a low basis weight, an excellent compactness, a low air permeability and an excellent economical efficiency. To provide a method.

[0009]

The present inventors have found that by controlling the pore distribution PD of the pores formed by the fibers constituting the woven fabric, a low basis weight and low air permeability non-woven fabric for non-coated airbags can be obtained. Found and completed the present invention.

The present invention has the following structure in order to solve the problems that cannot be achieved by the conventional methods described above.
That is, the manufacturing method of the airbag fabric of the present invention uses a thermoplastic fiber fabric Haraitonie water shrinkage is 5-15%, the step of performing contraction processing at 160 ° C. or less, Drying set finishing as well And a pore distribution value (PD) represented by the formula (Formula 1) of the pores formed by the thermoplastic fiber is 2.0 or less, and the air permeability when the differential pressure is 20 kPa. Is 2.5 (L / cm 2 / min) or less and is a low-permeability woven fabric for non-coated airbags.

The pore distribution is defined by the following equation (Equation 2).

[Equation 2] PD = (FDmax-FDmin) / FDave here, FDmax: Maximum pore size (μm) FDmin: Minimum pore size (μm) FDave: Average flow rate pore size (μm) Is.

[0012] Specifically, the feature of the method for producing a fabric for an air bag of the present invention is that the weaving shrinkage ratio of a fabric composed of thermoplastic fibers and the thickness and weave density of single fibers with respect to the thickness of multifilaments are adjusted. In addition, the raw yarn having a specific shrinkage rate of boiling water is used, and the shrinkage is controlled by heating to control the pore distribution.
The weaving density is preferably adjusted by adjusting the density of the greige and the weaving shrinkage ratio under weaving conditions. The pore distribution is more preferably 1.9 or less, and the air permeability is 1.4 or less as the non-coated airbag fabric obtained by the production method of the present invention.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The raw fiber boiling water shrinkage of the thermoplastic fiber used in the production method of the present invention must be 5 to 15%. If the shrinkage rate of the raw yarn boiling water is less than 5%, the desired low air permeability cannot be obtained, and if it is more than 15%, the thickness of the woven fabric after shrinkage becomes large and compactness is impaired, which is not preferable. The value of the shrinkage rate of the raw thread boiling water is 5 to
It is preferably about 15%, more preferably 8 to 12%.

The heat treatment temperature for performing the shrinkage treatment in the production method of the present invention is not particularly limited, and is usually 100 to 200 ° C. Preferably 160 ° C
The following treatment is suitable for obtaining low air permeability.
A device for performing the shrinking treatment is not particularly limited, such as a heat setter or a boiling water bath, but a device capable of vertical and horizontal overfeed of about 2 to 15% is used. In the present invention, since it is necessary to adjust the distribution of the pore size made of the fibers constituting the woven fabric, it is particularly preferable to use equipment that can handle such adjustment. Adjust the pore size by controlling the heat treatment temperature and limiting the overfeed rate,
It becomes possible to make uniform, and it is possible to manufacture a fabric for a non-coated airbag having a low basis weight and a low air permeability.

The pore distribution value of the non-coated airbag fabric in the production method of the present invention is a numerical value showing the distribution of pores made of the fibers constituting the fabric, and as shown in (Equation 2), the maximum It is a value obtained by dividing the difference between the pore size and the minimum pore size by the pore size at the average flow rate (average flow rate pore size). The pore distribution value PD of the present invention needs to be 2.0 or less, preferably 1.5 or less, and more preferably 1.3 or less. When the pore distribution value is larger than 2.0, a fabric having low air permeability cannot be obtained, which is not preferable.

The weaving method is not particularly limited, but a plain weave is preferable in consideration of the uniformity of the physical properties of the base cloth. The weaving machine used for weaving includes an air jet room, a rapier room, a water jet room and the like. It is illustrated and is not particularly limited.

As the thermoplastic fibers constituting the airbag in the manufacturing method of the present invention, aliphatic polyamide fibers such as nylon-6, nylon-6,6, nylon-4,6 and nylon-12, polyethylene terephthalate and poly are used. Examples thereof include polyester fibers such as butylene terephthalate, but are not particularly limited. However, in consideration of economy and impact resistance, it is particularly preferable to use polyamide fiber such as nylon-6,6, nylon-4,6, nylon-6. Further, there is no problem even if these synthetic fibers contain or are added with various additives in order to improve the process passability in the raw yarn manufacturing process and the post-processing process.
Examples of such additives include antioxidants, heat stabilizers, leveling agents, antistatic agents, flame retardants and the like.

Further, the total fineness and single yarn fineness of the raw yarn used are preferably 100 to 700 d and 8 d or less, more preferably the total fineness of the raw yarn used is 150 to 420 d. The single yarn fineness 4d is preferably as follows.

When the total fineness is less than 100 d, the tensile strength and tear strength of the fabric are insufficient, and when the total fineness is more than 700 d, the flexibility of the fabric is impaired, which is unfavorable for the storability and makes the airbag compact. We cannot respond to requests.

When the single yarn fineness exceeds 8d, this also impairs the flexibility of the woven fabric, which is disadvantageous for storability.

The air permeability in the present invention has a differential pressure of 20 kPa.
In, it is 2.5 L / cm 2 / min or less, preferably 1.5 L / cm 2 / min or less, and more preferably 1.0 L / cm 2 / min or less. If the air permeability is greater than 2.5 L / cm 2 / min, the deployability of the non-coated airbag is unfavorable.

The original yarn is preferably substantially untwisted or sweet twisted, more preferably untwisted. This is because, when trying to obtain a low air permeability woven fabric using a low single yarn fineness yarn, if twisting is applied, the spread of the single yarn is hindered and it becomes difficult to reduce the air permeability.

In the manufacturing method of the present invention, it is preferable that the difference in the weft shrinkage ratio between the warp and the weft of the woven fabric is 4% or less. If it is more than 4%, the maximum pore size in the pore distribution becomes large, and it is often difficult to obtain a fabric with low air permeability. The weaving shrinkage ratio of the present invention is 2 to 6% in order to reduce the pore distribution. , But is not limited to.

[0024]

The present invention will be described in more detail with reference to the following examples. The physical properties in the examples were measured by the following methods. Unit weight: JIS L1096 6.4.2 Woven density: JIS L1096 6.6 Air permeability: Made by OEM System Co., Ltd. Measured with an air flow rate measuring instrument: JIS L1096 6.19.1. Method A (4
5 ° cantilever method) Boiling water shrinkage ratio: JIS L1013 Hot water shrinkage ratio B method 1
00 ° C pore size (FDmax, FDmin, FDave):
COULTER ELECTRONICS LIMIT
Measured using ED's COULTER POROMETER.

(Example 1) 420d / 14 of untwisted warp
4f (single yarn fineness 2.9d), boiling water shrinkage = 9.5%, untwisted 420d / 144f (single yarn fineness 2.9d), boiling water shrinkage = 9.5% are used for the weft. After weaving a plain weave in a water jet loom, adjusting the overfeed rate with boiling water to perform shrinkage processing, and then dry-set finishing at 140 ° C to adjust the pore distribution value = 1.0. A non-coated airbag fabric was obtained. Table 1 shows the results of evaluating the physical properties of this non-coated airbag fabric.

(Example 2) Untwisted 315d / 10 warp
8f (single yarn fineness 2.9d) boiling water shrinkage = 9.5%, weft is untwisted 315d / 108f (single yarn fineness 2.9)
d), after weaving a plain weave in a water jet loom using a boiling water shrinkage rate of 9.5%, adjusting the overfeed rate with boiling water to perform shrinkage processing, and then dry set finishing at 130 ° C. The fabric for non-coated airbag was obtained by adjusting the distribution value to 1.2. Table 1 shows the results of evaluating the physical properties of this non-coated airbag fabric.

(Example 3) Untwisted 315d / 72 as warp
f (single yarn fineness 4.4d) boiling water shrinkage rate = 10.5% is used, and the weft is untwisted 315d / 72f (single yarn fineness 4.4
d), after weaving a plain woven fabric in a water jet room using a boiling water shrinkage ratio of 10.5%, adjusting the overfeed ratio with boiling water to perform shrink processing, and then dry set finishing at 140 ° C. It was adjusted so that the distribution value was 1.8, and a woven fabric for non-coated airbag was obtained. Table 1 shows the results of evaluating the physical properties of this non-coated airbag fabric.

Comparative Example 1 Untwisted 420d / 14 warp
4f (single yarn fineness 2.9d) boiling water shrinkage = 9.5%, untwisted 420w / 144f (single yarn fineness 2.9)
d), using a boiling water shrinkage rate of 9.5%, weaving a plain weave in a water jet room, adjusting the overfeed rate with boiling water to perform shrinkage processing, and then drying set finishing at 160 ° C. The unwoven fabric for airbags was obtained by adjusting the distribution value to 2.1. Table 1 shows the results of evaluating the physical properties of this non-coated airbag fabric.

(Comparative Example 2) Untwisted warp 315d / 72
f (single yarn fineness 4.4d) boiling water shrinkage rate = 10.5% is used, and the weft is untwisted 315d / 72f (single yarn fineness 4.4
d), after weaving a plain weave in a water jet loom using a boiling water shrinkage ratio of 10.5, adjusting the overfeed ratio with boiling water to perform shrinkage processing, and then dry set finishing at 180 ° C. to obtain a pore distribution The value was adjusted to be 2.4 to obtain a non-coated airbag fabric. Table 1 shows the results of evaluating the physical properties of this non-coated airbag fabric.

(Comparative Example 3) Untwisted warp 315d / 10
8f (single yarn fineness 2.9d) boiling water shrinkage = 9.5%, untwisted weft 315d / 108f, boiling water shrinkage =
After weaving a plain weave with 9.5% in a water jet loom, adjusting the overfeed rate with boiling water to perform shrink processing, and then dry set finishing at 170 ° C., the pore distribution value = 2.2. It was adjusted so that a non-coated airbag fabric was obtained. Table 1 shows the results of evaluating the physical properties of this non-coated airbag fabric.

[0031]

[Table 1] As is clear from Table 1, the fabric of the present invention has a low basis weight,
It can be seen that it is a low air permeability fabric.

[0032]

According to the present invention, it is possible to produce an economical airbag fabric having flexibility and low air permeability while maintaining the mechanical properties required for an airbag fabric, and having a low basis weight. can do.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) D03D 1/02 B60R 21/16

Claims (3)

(57) [Claims] 1. A Haraitonie water shrinkage using thermoplastic fibers is 5-15%, comprising the step of performing step, a sequence on Drying set finish performing contraction processing at 160 ° C. or less, the thermoplastic The pore distribution value (PD) represented by the formula (Formula 1) of the pores formed by the fibers is 2.0 or less, and the air permeability at a differential pressure of 20 kPa is 2.5 (L / cm2 / min). )
A method for producing a low-ventilation non-woven fabric for an airbag, characterized in that: ## EQU00001 ## PD = (FDmax-FDmin) / FDave FDmax: maximum pore size (μm) FDmin: minimum pore size (μm) FDave: average flow rate pore size (μm) 2. The method for producing a fabric for a non-coated airbag according to claim 1, wherein the difference in shrinkage ratio between the vertical and horizontal weaves is 4% or less. 3. The method for producing a woven fabric for an uncoated airbag according to claim 1, wherein the thermoplastic fiber is a polyamide fiber.