JPH06184856A - Low air-permeable woven fabric and its production - Google Patents

Abstract

PURPOSE:To provide low air-permeable woven fabric excellent in holdability. CONSTITUTION:The woven fabric which comprises synthetic fiber multifilament yarns 250-450 denier in fineness and >=6.5g/d in tenacity, is calendered and has the following characteristics: (1) thickness: <=0.25mm; (2) overlap ratio, i.e., the ratio of the width of mutually adjacent multifilaments-superposed region to that of each multifilament: (Wo/Wf): >=0.04; (3) bending resistance: <=75mm (warp, weft): and (4) air permeability at a differential pressure of 0.5 inch: <=0.2cm<3>/cm<2>/sec.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low air-permeable woven fabric using synthetic fiber multifilament yarn, and more particularly to a low breathable woven fabric suitable for use in an automobile airbag.

[0002]

2. Description of the Related Art Materials with extremely low air and water permeability are
Many applications such as mattresses, heat insulating materials, life boats, airbags, life jackets, etc. can be considered for enclosing these. Among them, an airbag is a high-pressure gas that is instantly injected into the interior of a vehicle to expand and maintain the safety of passengers when a car has a collision accident.The material used for the airbag is simply low-permeability. In addition, the strength required to withstand the shock of a collision, the storability under normal conditions, the lightness, etc. are required.

Conventionally, a fabric coated with a polymer film or synthetic rubber has been used as a material for an airbag. However, if a film is used, there is a problem in safety because the entire airbag ruptures due to the occurrence of minute damage. Further, the cloth coated with synthetic rubber inevitably increases in weight, and since it is thicker, it is difficult to store the cloth compactly and it is expensive.

Therefore, it has been studied to obtain a fabric having low air permeability without applying a coating process, and for example, Japanese Patent Laid-Open No.
Japanese Patent No. 137245 discloses a non-coated woven fabric having a warp and a weft in a symmetrical design. Further, JP-A-4-2835 discloses a low-permeability woven fabric such as a basket woven fabric using a high-strength filament yarn, which is calendered on both sides.

[0005]

However, even with the above-mentioned conventional techniques, a fabric having a low air permeability, which is still rich in flexibility, could not be obtained. Sunahachi, JP-A-3-13
As described in Japanese Patent No. 7245, there is a limit in obtaining low air permeability only by the fabric structure.

Further, in Japanese Patent Application Laid-Open No. 4-2835,
It is necessary to perform calendering on both sides to obtain low air permeability, but if both sides of the fabric are hardened by excessive calendering in this way, when the fabric is folded to store it, both the outer and inner perimeters are folded. The stress acts on the storage, which hinders storage.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a low air-permeable woven fabric excellent in storability.

[0008]

The present invention has a fineness of 250 to
A calendered high-density woven fabric made of synthetic multifilament yarn having a strength of 6.5 g / d or more at 450 denier, and having a thickness of 0.25 mm or less,
The width (Wo) of the area where the adjacent multifilaments overlap each other in the cross section of the fabric and the width of the multifilament (W
f) and the overlap ratio (Wo / Wf) is 0.
A low breathability woven fabric having a softness of at least 04, a stiffness of 75 mm or less and a differential pressure of 0.5 inch and an air permeability of 0.2 cm ³ / cm ² / sec or less, wherein the woven fabric has a fineness of 250.
Synthetic fiber multi-filament yarn having a strength of 6.5 g / d or more at 450 denier is used as a warp without twisting or with a twist number of 80 T / M or less, and then weaving a woven fabric,
15% shrinkage Cover factor (CF) 2300
The above is not done, and then calendering is applied to only one side, or 6.5 g / d with a fineness of 250 to 450 denier.
Synthetic fiber multi-filament yarn having the above strength,
Manufactured by weaving a woven fabric with no twist or warp of 60 T / M or less, shrinking the fabric by 3 to 15% and setting the cover factor (CF) to 2300 or more, and then calendering both sides. To be done.

Further, with a fineness of 250 to 450 denier, 6.
After sizing the synthetic fiber multi-filament yarn having a strength of 5 g / d or more, after weaving a woven fabric with no twist or with a twist number of 80 T / M or less, this is 3 to 15%
The woven fabric can also be obtained by setting the shrinkage cover factor (CF) to 2300 or more and then calendering at least one surface in a state where the sizing paste remains. CF = warp fineness ^0.5 (D) * number of warp yarns (per inch)
+ Weft fineness ^0.5 (D) * Number of wefts (pieces / inch)

The synthetic fiber filament yarn used in the present invention is not particularly limited as long as it satisfies the following physical properties, and examples thereof include polyester, polyamide, polybutylene terephthalate, etc., among which polyester is particularly preferable. The fineness of the synthetic fiber filament yarn is 250.
It should be ~ 450 denier. Sunahachi,
With ordinary synthetic fibers, if it becomes thinner than 250 denier, it becomes difficult to maintain the strength required for airbags,
When it exceeds 450 denier, the texture is hardened, the storage property is deteriorated, and the weight is increased. Further, the synthetic fiber filament yarn needs to be composed of multifilaments, and the single yarn fineness of the multifilaments is preferably 1 to 5 denier.

Further, the tenacity of the synthetic fiber filament yarn must be 6.5 g / d or more. Such synthetic fiber filament yarn uses a high-viscosity raw material and is stretched in multiple stages as is well known. It can be obtained by a method such as going.

The woven fabric is woven at a high density using such synthetic fiber multifilament yarns, and the structure is not limited as long as it can be finished at a high density, but in general, plain weave, basket structure, etc. Is preferred. The density of the woven fabric is not particularly limited as long as it exhibits the air permeability described below, but usually, the fineness of the warp is ^0.5 (D) * the number of warp (the number of /
(Inch) + weft fineness ^0.5 (D) * Cover factor (CF) indicated by the number of wefts (pieces / inch) will be 2300 or more.

Further, the fabric is of relatively thin fabric.
That is, the thickness measured by JIS L-1096 is 0.25 mm or less, and since it is such a thin fabric, it can be easily folded. Further, the weight per unit area of such a thin woven fabric will be 280 g / m ² or less when the ordinary synthetic fiber multifilament yarn is used.

An important point for the present fabric is the positional relationship between adjacent synthetic fiber multifilament yarns. The present fabric will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the present fabric, where 1 is a weft synthetic fiber multifilament yarn, 2
a and 2b are synthetic multifilament yarns of warp, 21
Indicates a single filament of a synthetic fiber multifilament yarn of a warp.

In FIG. 1, adjacent synthetic fiber multifilament yarns 2a and 2b are overlapped at their end portions with a weft yarn 1 in between. Here, if the width of the region is Wo and the width of the synthetic fiber multifilament yarn 2a is Wf, then Wo
/ Wf for both synthetic fiber multifilament yarns 2a,
An overlap rate of 2b is required.

The present woven fabric needs to have an overlap ratio of 0.04, preferably 0.1 or more when measured at several points on both the longitudinal and cross sections. When the overlap ratio becomes large, it becomes difficult to form a gap at the intersection of the multifilament of the warp and the multifilament of the weft, which contributes to the reduction of air permeability.

Further, the present woven fabric is calendered, and the single filament filament yarn in the surface layer is crushed and flattened by the calendering. However, the flattened single-filament filament yarn hardens and impairs storability, so it is advisable to keep calendering on only one side in a relatively high warp twisting condition, that is, in a high CF fabric.

Factors that enhance the air permeability include the above-mentioned overlap ratio and calendering, as well as the condition of the woven fabric surface. That is, when there are many irregularities on the surface of the woven fabric, there is a high possibility that voids will occur between the warp and weft yarns. The surface smoothness is preferably 6 μm or less in terms of surface roughness specified in the KES texture measuring method. The air permeability of this woven fabric is required to be 0.2 cm ³ / cm ² / sec or less at a differential pressure of 0.5 inch using a Kato Tech air permeability measuring device. That is, since this fabric is used as an airbag, when a mounting test is performed using a bag body of 60 l,
1.2 within 60/1000 seconds when the actual inflator operates
The internal pressure is not less than kg / cm ² G.

The softness of the woven fabric is JIS L1.
Bending flexibility of 096 method (cantilever method) 70 mm or less, K
Flexural rigidity 0.3 gfcm · cm measured by ES texture
/ Cm or less is preferable. Furthermore, the tensile strength (JIS L1096) of the woven fabric is preferably 290 kg / 5 cm or more, and the tear strength (JIS L1096A method) is preferably 14 kg or more.

The method for producing the present fabric will be described below in detail. First, when the above-mentioned synthetic fiber multifilament yarn is untwisted or when the calendering treatment described below is performed on one side, 80
T / M or less, and when it is performed on both sides, a woven fabric is woven using warps with a twist number of 60 T / M or less. When weaving normally,
Although additional twisting is performed to increase the convergence of the multifilament, in the present invention, synthetic fiber multifilament yarn is used without twisting or sweet twisting so as not to impede the diffusibility of the multifilament. As a result, the multifilament spreads on the product to improve the overlap ratio, resulting in a decrease in air permeability. On the other hand, if the synthetic fiber multifilament yarn is untwisted or has a twist number of 60 to 80 T / M or less, the convergence is poor at the time of weaving, and therefore waxing or sizing may be performed.

In this case, as the sizing paste, a sizing paste having a high heat resistance and a soft texture when dried is used, and the sizing paste is left on the woven fabric by omitting the refining treatment after weaving. If the sizing paste is spread on the woven fabric and then cured by calendering as described below, a woven fabric with extremely low air permeability can be obtained. Examples of the sizing paste include acrylic paste, polyester paste, and emulsion of a mixture of these with silicone oil. The sizing paste is applied to warp in a solid content of about 2 to 10% by weight. And dry it.

The synthetic fiber multifilament yarn may of course be woven by the present woven fabric only, but if it is about 20% by weight, another yarn that is subjected to additional twisting or has a relatively low strength. The articles may be mixed.

At the time of weaving, it is preferable to increase the driving density of the warp and the weft as much as possible and weaving near the weaving limit. For example, it is preferable that the weaving density of 450 denier is about 52 yarns / inch. Furthermore, it is preferable that the warp yarn and weft yarn have the same driving density.

In the present invention, the greige is contracted in the warp and weft directions by 3 to 10% respectively by refining, relaxing, etc. to finally obtain a woven fabric having a cover factor (CF) of 2300 or more. By shrinking the greige as described above, the synthetic fiber multifilament yarn having a low convergence is diffused to fill the gap between the warp and weft yarns and contribute to the improvement of the overlap ratio. Therefore, it is preferable that the shrinkage treatment is performed under tension control so that each single-filament filament exhibits a free behavior.

In the present invention, such a woven fabric is subjected to calendering. The single-sided calendering in the present invention means
The fact that the press surface of the heat roller is fixed to one side of the fabric means that the same treatment is applied to both sides of the fabric.

The conditions for calendering may be selected according to the type of synthetic fiber multifilament yarn used, but when ordinary polyester fiber is used, the surface temperature is 1
It is possible to use a heating roller of 40 to 190 ° C. under a pressure of about 50 to 100 tons.

In the above-mentioned method of spreading the sizing paste remaining by calendering without the refining step, calendering is preferably performed at a relatively low temperature and low pressure, for example, a surface temperature of 140 to 200 ° C. The heating roller may be used under a pressure of about 50 to 100 tons.

In the present invention, it goes without saying that various post-processings such as dyeing, softening, waterproofing, flameproofing and antibacterial may be applied. However, as described above, the coating process of the thick material which impairs the flexibility should not be adopted because it impairs the original purpose of the present fabric.

[0029]

【Example】

Example 1 A multifilament yarn (strength 8.5 g / d, entangle number 11 / m) made of 440d / 96f polyethylene terephthalate was used as a warp yarn without twisting, and warp 5
A plain woven fabric was woven with a driving density of 2 yarns / inch and weft 52 yarns / inch.

10% by refining and relaxing this raw material
A woven fabric having a cover factor (CF) 2412 was contracted to obtain a woven fabric, and then only one side thereof was pressed using a calender (paper roll manufactured by Yuri Roll) at 185 ° C. under a pressure of 80 tons and 160 cm width.

The results are shown in Table 1, and electron micrographs (3
Fig. 2 is an electron micrograph (100 times) of the warp cross section.
3) are shown in FIG. 3, respectively. As is clear from the table, this woven fabric had extremely low air permeability, and had low bending rigidity and bending resistance, and was flexible.

[0032]

[Table 1]

Further, a bag body having a diameter of 0.5 m was manufactured using this woven fabric and was filled with gas, and the internal pressure was 1.2 kg /
It became more than cm ² . Further, the bag could be stored in a space having a thickness of 30 mm without any problem, and could be sufficiently used as an air bag of an automobile.

Example 2 The number of additional twists of the warp is 80 T / M and the driving density is 52 warps /
A plain weave fabric was obtained in the same manner as in Example 1 except that the inch and the weft were 52 threads / inch.

This greige was scoured and contracted by 6% to be relaxed to obtain a cover factor (CF) 2328 woven fabric, which was then calendered in the same manner as in Example 1. The results are shown in Table 1.

Example 3 A plain weave fabric was obtained in the same manner as in Example 1 except that warp yarns of 380d / 192f were used and the shot density was 62 warps / inch and weft 62 yarns / inch.

This greige machine was refined and shrunk to shrink it by 6% to obtain a cover factor (CF) 2417 woven fabric, which was then calendered in the same manner as in Example 1. The results are shown in Table 1.

Example 4 The number of additional twists of the warp is 50 T / M and the driving density is 52 warps /
A plain weave fabric was obtained in the same manner as in Example 1 except that the inch and the weft were 52 threads / inch.

This greed is refined and relaxed for 8 days.
%, Weft 4% Shrink and cover factor (CF) 23
No. 22 woven fabric, and then using a calender machine (paper roll made by Yuri Roll) at 185 ° C., 80 tons, 160
Both sides were pressed under a pressure of cm width. The results are shown in Table 1.
Shown in.

Comparative Example 1 A plain woven fabric was obtained in the same manner as in Example 2 except that the shot density was 52 warps / inch and weft 52 threads / inch.

This greige was smelted and shrunk to shrink it by 5% to form a cover factor (CF) 2307 woven fabric, and then a calender machine (paper roll made by Yuri Roll) was applied at 185 ° C., 80 tons, 160 cm width. Both sides were pressed under pressure.

The results are shown in Table 1. As is clear from the table, the woven fabric had a high stiffness and a high bending rigidity, and had a rugged texture. Furthermore, when a bag body having a diameter of 0.5 m was manufactured using this woven fabric and it was intended to be stored in a space having a thickness of 30 mm, folding took a long time and it could not be stored unless pressure was applied.

Comparative Example 2 A driving density of 50 lines / inch, weft 50 lines / inch,
A plain woven fabric was obtained in the same manner as in Example 2 except that the additional twist number of the warp was 120 T / M.

This greige was smelted and shrunk to shrink it by 4% to form a cover factor (CF) 2265 woven fabric, which was then pressed on one side only as in Example 1.

The results are shown in Table 1 as an electron micrograph (30
Fig. 4 is an electron micrograph (100 times) of the warp cross section.
Are shown in FIG. 5, respectively. As is clear from the table, this fabric is
The fabric was inferior in air permeability, and a bag having a diameter of 0.5 m was produced using this woven fabric and was filled with gas, but the internal pressure was only 0.8 kg / cm ² .

Example 5 A multi-filament yarn of 440d / 96f polyethylene terephthalate (strength 8.5g / d, entangle number 11 / m) was warped without twisting, and a sizing agent having the following composition was solidified. It was wound on a beam by applying 10% by weight per minute.

Glue composition Acrylic ester type emulsion J-6 55 parts made by Kyodo Chemical Silicone oil emulsion Sytex 53 45 parts made by Kyodo Chemical

Next, the multifilament yarn is also used as the weft yarn without twisting, and 52 warps / inch and 52 wefts /
A plain weave was woven with a shot density of inch. This greige was relaxed to shrink 10% to form a cover factor (CF) 2412 woven fabric, without refining,
With the sizing agent remaining on the warp, use a calendar machine (paper roll made by Yuri Roll) at 180 ° C and 80 tons
Both sides were pressed under a pressure of 160 cm width.

The results are shown in Table 1. As is clear from the table, the woven fabric had extremely low air permeability and low bending resistance and flexibility. Furthermore, a bag body with a diameter of 0.5 m was manufactured using this woven fabric, and when gas was filled, the internal pressure was 1.2 kg.
/ Cm ² or more. Further, the bag could be stored in a space having a thickness of 30 mm without any problem, and could be sufficiently used as an air bag of an automobile.

[0050]

INDUSTRIAL APPLICABILITY The present invention has a sufficiently low air permeability as an airbag material for automobiles and is excellent in foldability and light weight, and therefore can be stored in a narrow space.

The method of the present invention is extremely useful because such a low air-permeable fabric can be effectively produced using conventional production equipment.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of the present fabric.

FIG. 2 is an electron micrograph of the surface of the present fabric, showing the shape of fibers.

FIG. 3 is an electron micrograph of a warp cross section of the present fabric,
It shows the shape of the fiber.

FIG. 4 is an electron micrograph of the surface of the fabric of Comparative Example,
It shows the shape of the fiber.

FIG. 5 is an electron micrograph of a warp cross section of a woven fabric of a comparative example, showing a fiber shape.

Claims (4)

[Claims] 1. 6.5 g with a fineness of 250 to 450 denier
A high-density calendered woven fabric composed of synthetic fiber multifilament yarns having a strength of / d or more, and having a thickness of 0.25 mm or less and a width (Wo ) And the width (Wf) of the multifilament, the overlap ratio (Wo / Wf) is 0.04 or more, the bending resistance is 75 mm or less in both directions, and the air permeability is 0.5 when the differential pressure is 0.5 inch. 2c
A low breathable woven fabric having m ³ / cm ² / sec or less. 2. 6.5 g with a fineness of 250 to 450 denier
Synthetic fiber multifilament yarn having a tenacity of / d or more is used as a warp without twisting or with a twist number of 80 T / M or less, and then a woven fabric is woven, and then contracted by 3 to 15% to obtain a cover factor (CF) of 2300. A method for producing a low-breathable woven fabric, characterized in that the above is followed, and then calendering is applied to only one side. CF = warp fineness ^0.5 (D) * number of warp yarns (per inch)
+ Weft fineness ^0.5 (D) * Number of wefts (pieces / inch) 3. 6.5 g with a fineness of 250 to 450 denier
Synthetic fiber multifilament yarn having a tenacity of / d or more is used as a warp without twisting or with a twist number of 60 T / M or less, and then a woven fabric is woven and then contracted by 3 to 15% to obtain a cover factor (CF) of 2300. A method for producing a low-breathable woven fabric, characterized in that the above is followed, and then both sides are subjected to calendering. CF = warp fineness ^0.5 (D) * number of warp yarns (per inch)
+ Weft fineness ^0.5 (D) * Number of wefts (pieces / inch) 4. 6.5 g with a fineness of 250 to 450 denier
The synthetic fiber multifilament yarn having a tenacity of / d or more is sized, and after weaving a woven fabric with no twist or with a twist number of 80 T / M or less, it is shrunk by 3 to 15% and the cover factor (CF 2) or more, and calendering is applied to at least one surface of the sizing paste with the sizing paste remaining. CF = warp fineness ^0.5 (D) * number of warp yarns (per inch)
+ Weft fineness ^0.5 (D) * Number of wefts (pieces / inch)