JP2008156798A - Coated fabric for airbag, and airbag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base fabric for airbag which is excellent in adhesiveness of synthetic resin layers of coated fabrics with an adhesive for filling a gap between two sheets of coated fabrics so as to have high airtightness and excellent also in adhesiveness of a base fabric constituting the coated fabric with the synthetic resin layer when a curtain air bag is inflated and deployed. <P>SOLUTION: The coated fabric for airbags is obtained by laminating the synthetic resin layer on at least one surface of a woven fabric composed of a synthetic fiber. In the coated fabric, the surface roughness (SMD) of the surface of the synthetic resin layer in warp direction and weft direction of a woven fabric by KES measurement is 10-50 μm, and releasability of the synthetic resin layer, measured based on JIS K 6404-6, is fifth class. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coated fabric for an airbag and an airbag.

  A side bag with a built-in seat and a curtain-type side bag (hereinafter referred to as a curtain airbag) that descends from the roof side of the vehicle to the side window have been developed and installed for collisions on the side of the car, that is, for a side collision. There are also more cars to do. These side bags, especially curtain airbags, require high airtightness to maintain the internal pressure of the airbag for a long time (several seconds) so that no occupant is released outside the vehicle even when the vehicle rolls over. .

  In order to increase the airtightness of the curtain airbag, for example, a coated fabric coated with rubber or resin such as silicone, polyurethane, chloroprene is used as the base fabric.

  However, in the curtain airbag, airtightness that suppresses air leakage from the sewing portion is required.

In order to suppress air leakage from the sewing portion, Patent Document 1 discloses that base fabrics are sewn together with an adhesive. However, the adhesive and the coated fabric are peeled off during the airbag deployment because the adhesive between the adhesive that fills the gap between the two base fabrics of the sewing portion and the synthetic resin layer of the coated fabric is insufficient. There was a problem that a gap was generated and air leakage occurred. On the other hand, since the adhesiveness between the synthetic resin layer of the coated fabric and the base fabric is insufficient, there is also a problem that the synthetic resin layer and the base fabric are peeled off during deployment of the airbag.
JP 2001-001854 A

  The present invention provides an air bag coat that is excellent in adhesiveness between an adhesive that fills a gap between two coated fabrics and a synthetic resin layer of the coated fabric, and also excellent in adhesiveness between a fabric constituting the coated fabric and the synthetic resin layer. An object is to provide a fabric.

  That is, the present invention is a coated fabric in which a synthetic resin layer is laminated on at least one surface of a woven fabric made of synthetic fibers, and the surface roughness (SMD) of the surface of the synthetic resin layer in the warp and warp directions of the woven fabric is measured by KES measurement. ) Is 10 to 50 μm, and the peelability of the synthetic resin layer measured based on JIS K 6328 is grade 5.

  Moreover, this invention is an airbag characterized by sewing the coat fabric for airbags of this invention.

  According to the present invention, when the airbag is inflated and deployed, the adhesive between the adhesive agent filling the gap between the two coated fabrics and the synthetic resin layer of the coated fabric is excellent, and the coated fabric has high airtightness. It is possible to provide a coated fabric for an air bag excellent in adhesion between the woven fabric constituting the fabric and the synthetic resin layer.

  In addition, the airbag of the present invention has high airtightness when deployed, and can prevent not only air leakage from the entire coated fabric for the airbag but also air leakage from the sewing portion.

  Synthetic fibers constituting the fabric of the coated fabric for airbag of the present invention include nylon 6,6, nylon 6, nylon 12, nylon 4,6, a copolymer of nylon 6 and nylon 6,6, Synthetic fibers made of polyamide such as those obtained by copolymerizing alkylene glycol, dicarboxylic acid, amine or the like can be preferably used. Among these, nylon 6,6 and nylon 6 are particularly preferably used from the viewpoint of impact resistance, and nylon 6,6 is particularly preferably used from the viewpoint of heat resistance.

  The synthetic fiber preferably contains various additives such as a heat stabilizer, an antioxidant, a light stabilizer, a smoothing agent, an antistatic agent, a plasticizer, a thickener, a pigment, and a flame retardant.

  As the cross-sectional shape of the synthetic fiber, the ratio between the major axis and the minor axis, that is, the aspect ratio is preferably 1.2 to 2.5. By setting the aspect ratio to 1.2 or more, the surface of the woven fabric can be made flat, and the surface of the synthetic resin layer formed thereon can also be made flat. In addition, by setting the aspect ratio to 2.5 or less, moderate unevenness is left on the surface of the fabric, and the resin forming the synthetic resin layer can penetrate into the interior of the fabric, thus maintaining the adhesion between the fabric and the synthetic resin layer. can do. In addition, by using fibers having an aspect ratio of 1.2 to 2.5, it is possible to improve the storage property while ensuring low air permeability and strength. The specific cross-sectional shape of the synthetic fiber may be a left-right asymmetric type other than a left-right symmetric type such as an ellipse, a rectangle, a rhombus, and a saddle type, or a combination thereof. Moreover, you may have a processus | protrusion, a dent, a hollow part, etc. by using these as a basic type.

  The single fiber fineness of the synthetic fiber is preferably 1 to 12 dtex, more preferably 3 to 8 dtex. By setting it to 1 dtex or more, the strength of the woven fabric can be maintained. On the other hand, by setting it to 12 dtex or less, rigidity can be suppressed low and storage property can be maintained.

  The total fineness of the multifilaments of the warp and weft constituting the woven fabric is preferably 100 to 700 dtex, more preferably 150 to 600 dtex. By setting it to 100 dtex or more, the tear strength and the like of the woven fabric can be maintained. On the other hand, by setting it to 700 dtex or less, the thickness of the woven fabric can be suppressed and the storage property can be maintained.

  As the woven structure of the woven fabric, a plain structure, an oblique structure, a satin structure, and the like can be adopted. Of these, a plain structure is preferable from the viewpoints of uniform mechanical properties, ease of mass production, cost reduction by high-speed production, stability of the woven structure, and the like.

The cover factor (CF) of the woven fabric is preferably 1200 to 2100, more preferably 1400 to 1900 from the viewpoint of mechanical properties and storage properties. By setting it to 1200 or more, the mechanical properties of the fabric can be maintained. On the other hand, by setting it to 2100 or less, there is no problem in mechanical characteristics, but the storage property can be maintained.
The cover factor (CF) is defined by the following equation.
CF = CF1 + CF2
CF1 = (Dw × 0.9) 1/2 × Nw
CF2 = (Df × 0.9) 1/2 × Nf
Here, CF: Cover factor CF1: Cover factor of warp yarn CF2: Cover factor of weft yarn Dw: Total fineness of warp yarn (dtex)
Df: Total fineness of the weft yarn (dtex)
Nw: Woven density of warp yarn (main / 2.54cm)
Nf: Weft density of the weft yarn (main / 2.54 cm).

  As a loom for the weaving process, a water jet room, an air jet room, a rapier room, or the like can be used. In particular, a water jet loom that is relatively easy to weave at high speed is preferably used in terms of increasing productivity.

  The coated fabric for airbag of the present invention requires that a synthetic resin layer is laminated on at least one side of the woven fabric. By laminating a synthetic resin layer on the woven fabric, air barrier properties can be provided, and when the airbag is deployed at the time of a vehicle collision, the bag can be inflated for a certain period of time to further reduce the occupant's impact. Furthermore, the fabric constituting the airbag coated fabric can be protected from the high-temperature nitrogen gas generated from the inflator.

  Examples of the resin of the synthetic resin layer include a silicone resin, a polyamide-based resin, a polyurethane resin, and a fluororesin. Of these, silicone resins are particularly preferably used. As the silicone resin, dimethyl silicone, methyl vinyl silicone, methyl phenyl silicone, fluoro silicone, and the like are preferably used.

  Moreover, it is also preferable that the synthetic resin layer contains a flame retardant. Examples of the flame retardant include halogen compounds such as bromine and chlorine, particularly halogenated cycloalkanes, platinum compounds, antimony oxides, copper oxides, titanium oxides, phosphorus compounds, thiourea compounds, carbon, cerium, and the like. Of these, halogen compounds, platinum compounds, copper oxide, titanium oxide and carbon are more preferably used.

  As a method for forming the synthetic resin layer on the woven fabric, the viscosity of the woven fabric is 10,000 to 50,000 mPa · s, preferably 10,000 to 20,000 mPa · s, under a tension of 0.5 to 3.0 kN / m. The solvent-free silicone resin prepared in s is preferably applied by floating knife coating. By doing so, the resin which forms a synthetic resin layer can osmose | permeate the inside of a textile fabric, the adhesiveness of a textile fabric and a synthetic resin layer can be improved, and the surface of a synthetic resin layer can be made flat.

  Moreover, after providing a synthetic resin, it is preferable to heat-process at 50-200 degreeC, Preferably it is 100-180 degreeC, in order to form a synthetic resin layer flat on the textile surface. Moreover, it is good also as a two-step heat processing as needed.

  The synthetic resin layer can be formed after weaving the fabric, after scouring, after drying, and after heat setting.

The amount of lamination in the synthetic resin layer is preferably 10 to 45 g / m ² , more preferably 15 to 30 g / m ² in terms of the smoothness, occupant restraintability and flexibility of the synthetic resin layer on the fabric surface. By setting it to 10 g / m ² or more, the synthetic resin layer can be formed uniformly and with a flat surface. Moreover, low air permeability can be obtained. On the other hand, a storage property can be maintained by setting it as 45 g / m < ² > or less.

  Moreover, the base fabric for airbags of this invention needs that the peelability of the textile fabric measured based on JISK6404-6 and a synthetic resin layer is a 5th grade. When the resin peeling becomes 4th grade or less, the base fabrics are rubbed together at the time of airbag deployment, the resin peels off, the hot air gas leaks from that portion, the internal pressure required as an airbag is not obtained, and the passenger is in a dangerous state There is a possibility.

  Further, the surface characteristics of the coated fabric of the present invention are as follows: the surface roughness of the synthetic resin layer in the KES measurement in the warp direction and the weft direction (SMD: Mean device of surface roughness [mean device of the thickness <unit: micron>]) It is important that the stylus surface roughness (SMD) in KES measurement is determined by placing the KES specified contact on the sample and detecting the surface roughness from the vertical movement of the contact. When the surface roughness is larger than 50 μm, the surface of the base fabric becomes uneven, and the synthetic resin layer surfaces of the two coated fabrics are sewn via an adhesive. In an airbag that seals the part, the adhesion between the surface of the synthetic resin layer and the adhesive deteriorates, and the airbag When the air bag is deployed at a high speed, the fabric and the synthetic resin layer peel off, and air leaks from the peeled portion when the surface roughness is less than 10 μm. It becomes a cause and it becomes difficult to deploy an airbag at high speed.

It is preferable that the storing property measured based on ASTM D-6478-02 is 1000 to 1850 cm ³ for the coated fabric for an airbag of the present invention. By setting it to 1850 cm ³ or less, even a large capacity airbag such as a curtain airbag can be easily accommodated in the airbag cover. However, even if the value is too low, it is difficult to handle and the storage workability in the airbag cover is inferior. Therefore, the value is preferably 1000 cm ³ or more.

The air permeability of the coated fabric for an airbag of the present invention is preferably 0.1 L / cm ² · min or less from the viewpoint of restraining the occupant at the time of collision. Further, 0.0 L / cm ² · min is preferable in terms of inflating the base fabric for a certain period of time against a rollover of the vehicle due to a side collision or the like.

The airbag of the present invention is formed by sewing the coated fabric for an airbag of the present invention.
In particular, since the coated fabric for airbags of the present invention is excellent in the adhesiveness between the adhesive that fills the gaps between the coated fabrics and the synthetic resin layer of the coated fabric, the airbag of the present invention is particularly suitable between fabrics via an adhesive. A mode of sewing is preferable.

[Measuring method]
(1) Thickness Based on JIS K 6404-2-3: 1999 B method, the thickness was measured.
With the exception of the 50 mm edge of the sample, 5 locations were measured with a thickness meter so as not to depend on them, and the arithmetic average value was obtained.

(2) Weight per unit area JIS K 6404-2-2: 1999 The basis weight was measured according to Test Method A.
Five test pieces of 25 cm × 25 cm were taken at equal intervals in the diagonal direction over the entire width excluding 50 mm from the ear.
The average value of 5 sheets was calculated by dividing the mass of the test piece by the area of the test piece.
The average value was measured.
Weight per unit area (g / m ² ) = m × 10 ⁴ / A
Where m: mass of the test piece (g)
A: Area (cm ² ) of the test piece.

(3) Tensile strength and elongation at break JIS K6404-3 Test method B: Measured according to the strip method.
For the warp direction, five rectangular test pieces with a length of 250 mm and a width of 30 mm, with a line parallel to the warp yarn being taken as one side, are marked with 100 mm intervals at the center, and the mark A grab line was placed at a position of 25 mm each outside. This was used as a test piece in the vertical direction. Similarly, five test pieces were taken in the horizontal direction.
The test piece is attached to a tensile tester with a grip interval of 150 mm, pulled at a pulling speed of 200 mm / min, and the tensile strength and breaking elongation are calculated from the load at break and the distance between the marked lines by the following formulas. The average value of 5 sheets was calculated for each of the direction and the horizontal direction.
T _B = F _B / W
Where, T _B : Tensile strength (N / cm)
W: Specimen width (cm)
F _B : Load at break (N)
E = [(L−L ₀ ) / L ₀ ] × 100
Where E: elongation at break (%),
L ₀ : initial distance between marked lines (100 mm)
L: Distance (mm) between marked lines at the time of cutting.

(4) Tear strength JIS K 6404-4: 1999 Test method B: Tear strength was measured based on the single tongue method.
From the sample, five test pieces were collected in both the vertical and horizontal directions, with a test piece having a long side of 200 mm and a short side of 76 mm. A test piece in which the cut was perpendicular to the warp yarn direction was taken as a test piece in the horizontal direction, and a test piece in which the cut was parallel to the longitudinal direction of the warp yarn was taken as a test piece in the warp direction.
Make a 75 mm incision with a sharp blade in the middle of the short side of the test piece, attach it to a tensile tester with a gripping interval of 75 mm, pull at a pulling speed of 200 mm / min, measure the load at break, The average value of 5 sheets was calculated for each of the horizontal directions.

(5) Storability Measured based on ASTM D-6478-02.

(6) Surface roughness Surface roughness (SMD: mean development of the roughness (mean development of the thickness (unit: micron))) With a surface testing machine (KES FB4), a coated fabric (width 20 cm, length 20 cm) Measured under KES standard conditions (The Standardization and Analysis of Hand Evaluation, 7.2nd Ed. S. Kawabata, 8. The Textile Machine Society of Japan, 9. 1980). The measurement conditions were a KES specified contact (consisting of a 0.5 mm diameter piano wire) attached to the device, contact load 10 gf, pressure spring constant 25 gf / m, measurement 0.1 cm / sec, holding tension of horizontal holding fabric sample Was 20 gf / cm. For the measurement, the average of n = 5 times was obtained by changing the sample.

(7) Peelability between the synthetic resin layer of the coated fabric and the woven fabric In accordance with JIS K6404-6, the surface of the synthetic resin layer was overlapped using a Scott-type paddle tester, and the following criteria were used. evaluated. The larger the releasability series, the better the adhesion between the synthetic resin layer and the fabric.
First grade: All synthetic resin layers peel from the fabric.
Second grade: Almost all the synthetic resin layer peels from the fabric.
Third grade: Part of the synthetic resin layer peels from the fabric.
Fourth grade: The synthetic resin layer hardly peels from the fabric.
Grade 5: The synthetic resin layer does not peel from the fabric at all.

(8) Adhesiveness between the synthetic resin layer of the coated fabric and the adhesive The silicone adhesive (Toray Industries Inc.) with two test pieces of 250 mm x 50 mm along the vertical / horizontal direction or the horizontal / vertical direction with the synthetic resin layer surface inside Using Dow Corning SE960), an adhesive part having a length of 100 mm or more was applied, and the adhesive was applied to a thickness of 0.6 mm by pressing for 10 seconds with a standard machine for 24 hours ( (20 ° C., 65% RH). Thereafter, the sample was cut so that the width was 20 mm. Thereafter, both ends of the non-adhered portion not bonded to the chuck of the constant-speed tension type tensile tester were attached, the sample was pulled at a test speed of 50 mm / min, and the load while the sample was peeled was recorded. The load peak values of five test pieces were read for both the vertical / horizontal directions.

(9) Combustibility Combustion speed was measured by FMVSS302.

(10) Air permeability of coated fabric The air permeability when tested at a test differential pressure of 19.6 kPa was measured according to JIS L 1096: 1999 (8.27.1 A method (Fragile type method)). Samples of about 20cm x 20cm are collected from 5 different locations of the sample, attached to one end of a cylinder with a diameter of 100mm, fixed so that there is no air leakage from the mounting location, and a test differential pressure using a regulator. It adjusted to 19.6 kPa, the air quantity which passes a test piece at that time was measured with the flowmeter, and the average value about five test pieces was computed.

(11) Bending resistance Measured according to JIS L 1096: 1999 8.19.1 A method (45 ° cantilever method). For each of the vertical and horizontal directions, five test pieces each having a width of 2 cm and a length of about 15 cm were sampled and placed on a cantilever type tester with the short side of the test piece aligned with the scale base line. Next, the test piece was gently slid in the direction of the slope of the cantilever type tester, and the position of the other end when the center point of one end of the test piece was in contact with the slope was read with a scale. The length (mm) that the test piece moved was measured on the front and back of the test piece, and the average value was calculated for each of the vertical and horizontal directions.

[Example 1]
(Warp and weft)
Filament yarn made of untwisted nylon 6.6 fibers with a single fiber cross-sectional aspect ratio of 2.0, total fineness of 470 dtex, 108 filaments, strength of 8.5 cN / dtex, and elongation of 23.5% is used as warp and weft It was.

(Weaving)
Using the warp and weft, a plain woven fabric having a weaving density of 43 pieces / 2.54 cm in both the warp and weft was obtained in a water jet loom.

(Resin coat)
The above woven fabric is coated with a solvent-free silicone resin solution having a viscosity of 12,000 mPa · s with a floating knife coater at a tension of 2.0 kN / m, and vulcanized at 190 ° C. for 1 minute to adhere the resin. An air bag coated fabric having an amount of 18 g / m ² was obtained.

  This airbag-coated fabric was excellent in the adhesiveness between the synthetic resin layer and the woven fabric, the adhesiveness with the adhesive, and the low air permeability.

[Example 2]
(Warp and weft)
Filament yarn made of untwisted nylon 6.6 fiber with a single fiber cross-section aspect ratio of 2.4, total fineness of 350 dtex, 72 filaments, strength 8.5 cN / dtex, elongation 23.5% is used as warp and weft It was.

(Weaving)
Using the warp and weft, a plain woven fabric having a weaving density of 53 yarns / 2.54 cm for both the warp and the weft was obtained in a water jet loom.

(Resin coat)
The above woven fabric is coated with a solvent-free silicone resin liquid having a viscosity of 40,000 mPa · s with a tension of 1.8 kN / m using a floating knife coater, and vulcanized at 190 ° C. for 2 minutes to adhere the resin. An air bag coated fabric having an amount of 25 g / m ² was obtained.

  This airbag-coated fabric was excellent in the adhesiveness between the synthetic resin layer and the woven fabric, the adhesiveness with the adhesive, and the low air permeability.

[Comparative Example 1]
(Warp and weft)
Filament yarns made of untwisted nylon 6.6 fibers with a single fiber cross-section aspect ratio of 1.0, total fineness of 470 dtex, 108 filaments, strength of 8.5 cN / dtex and elongation of 23.5% are used as warp and weft It was.

(Weaving)
Using the warp and weft, a plain woven fabric having a weaving density of 43 pieces / 2.54 cm in both the warp and weft was obtained in a water jet loom.

(Resin coat)
The above woven fabric is coated with a solvent-free silicone resin solution having a viscosity of 18,000 mPa · s with a floating knife coater at a tension of 0.2 kN / m, and vulcanized at 190 ° C. for 1 minute to adhere the resin. An air bag coated fabric having an amount of 25 g / m ² was obtained.

  This airbag coated fabric had no problem with respect to flexibility and low air permeability, but had poor adhesion with an adhesive.

[Comparative Example 2]
(Warp and weft)
Filament yarns made of untwisted nylon 6.6 fibers with a single fiber cross-sectional aspect ratio of 3.2, total fineness of 350 dtex, 72 filaments, strength of 8.5 cN / dtex and elongation of 23.5% are used as warp and weft It was.

(Weaving)
Using the warp and weft, a plain woven fabric having a weaving density of 50 yarns / 2.54 cm for both warp and weft was obtained in a water jet loom.

(Resin coat)
The above woven fabric is coated with a solvent-free silicone resin solution having a viscosity of 55,000 mPa · s with a floating knife coater under a tension of 2.5 kN / m, and subjected to vulcanization treatment at 190 ° C. for 2 minutes. An airbag coated fabric having an adhesion amount of 40 g / m ² was obtained.

  This coated fabric for airbags had no problem with respect to flexibility, low air permeability, and adhesiveness with an adhesive, but was inferior in adhesiveness between the synthetic resin layer and the woven fabric.

Note that the description of “numerical value / numerical value” in the table represents the “value in the vertical direction / value in the horizontal direction” of the characteristic value.

  The coated fabric for airbags of the present invention is suitable for side airbags with a built-in seat for side collision that require high airtightness, and curtain-type side airbags that descend from the roof side of the vehicle onto the side windows. Can be used for Further, it may be used for a driver seat, a passenger seat, and a rear seat.

Claims (6)

A coated fabric in which a synthetic resin layer is laminated on at least one side of a woven fabric made of synthetic fibers, and the surface roughness (SMD) measured by KES measurement of the surface of the synthetic resin layer in the warp direction and the weft direction of the woven fabric is 10 to 50 μm And the peelability of the synthetic resin layer measured based on JISK6404-6 is 5th grade, The coated fabric for airbags characterized by the above-mentioned. The coated fabric for an airbag according to claim 1, wherein the synthetic fiber has a cross-sectional shape having an aspect ratio of 1.2 to 2.5. The coated fabric for an airbag according to claim 1 or 2, wherein the synthetic resin layer comprises a solventless silicone resin. The combined amount laminate of the resin layer is 10 to 45 g / ^{m 2,} air bags coated fabric according to any one of claims 1 to 3. The coat fabric for airbags in any one of Claims 1-4 whose storage property measured based on ASTM D-6478-02 is 1000-1850cm < ³ >. An airbag comprising the airbag coated fabric according to any one of claims 1 to 5 sewn.