JP2013023784A - Base cloth for air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air bag that is light and small, is excellent in expansion efficiency due to suppressed air permeability under a high pressure, and is excellent in a burst resistance property to bear an inflow of a high pressure gas, and a base cloth for an air bag composing the same.SOLUTION: The base cloth for an air bag includes a synthetic fiber woven cloth, and has a tensile strength of 500 N/cm or more both in warp and weft directions in a tensile test, a ratio of elongation at a load of 300 N/cm is 40% or more in total in warp and weft directions, a maximum tensile resistance is 90cN/dtex or more in total in warp and weft directions, and a load seam permeability (permeability under a differential pressure of 50kPa after imparting a tensile load of 1,500 N/15 cm to a specific seam) of 2000 mm/s or less as an average of permeability in warp and weft directions after being loaded.

Description

  The present invention is intended to protect the occupant by restraining the occupant in the collision accident of the vehicle, or in the accident where the pedestrian outside the vehicle comes into contact with the vehicle, by ensuring a gap with the pedestrian on the surface of the vehicle. The present invention relates to an airbag that performs an impact absorbing function by inflating a bag with air or gas in the event of an accident and a base fabric that constitutes the airbag.

  In order to protect the occupants, the mounting of airbags on vehicles has become widespread, and the number of places where airbags are mounted in vehicles has increased. For example, a knee airbag for protecting the knee is mounted in addition to the front collision airbag for the driver seat and the passenger seat. Furthermore, side curtain airbags and side impact airbags are installed for side collisions, and the installation of pedestrian protection airbags that inflate and deploy outside the vehicle for pedestrian protection is also expanding. On the other hand, weight reduction of the vehicle is desired from the viewpoint of energy saving. Therefore, a small and lightweight airbag having a small storage volume is desired.

  Hitherto, in order to reduce the weight of an airbag, it has been proposed to use a base fabric having a low weight per unit area, which is made of low-definition fibers (see Patent Document 1 below). However, when a fiber having a low fineness is simply used, the mechanical properties of the base fabric are lowered. Furthermore, the required characteristics of airbags have increased demands for higher-speed collision response and higher-speed deployment, and could not meet these requirements. In other words, even if low-fineness and high-strength fibers are used, the characteristics of the high-strength fibers do not match, and the airbag using this base fabric cannot fully control the air permeability under high pressure, and has the airbag characteristics. I couldn't show it. In addition, even under the base fabric processing conditions, it cannot withstand rapid high-pressure gas inflow, and the airbag characteristics may not be exhibited.

WO99 / 22967 pamphlet

  An object of the present invention is to provide a lightweight and small airbag, which has excellent inflation efficiency because air permeability under high pressure is suppressed, and has excellent burst resistance that can withstand high-pressure gas inflow. is there. Furthermore, the present invention is to provide an airbag having a large inflated size at the time of inflation and having further excellent storability, and an airbag base fabric constituting the airbag.

The inventor suppresses the breathability under high pressure by a base fabric having specific characteristics, improves the burst resistance to withstand high pressure gas inflow, and further, the expansion size at the time of expansion is large, The present inventors have found that an airbag having a further reduced storage capacity can be obtained when folded and stored while securing a passenger restraint area at the time of deployment.
That is, the present invention is as follows.

(1) It consists of a synthetic fiber fabric, the tensile strength in the tensile test is 500 N / cm or more in the weft direction, the elongation at 300 N / cm load is 40% or more in the total direction, and the maximum tensile resistance is the history. The total direction is 90 cN / dtex or more, and the load stitch air permeability (the air permeability under a differential pressure of 50 kPa after applying a tensile load of 1,500 N / 15 cm to a specific stitch) is An air bag base fabric having an average air permeability of 2000 mm / s or less.
(2) The airbag fabric according to the above item (1), wherein the fabric weight is 200 g / m ² or less.
(3) The airbag fabric according to item 1 or 2, wherein the cover factor of the fabric is 2100 or more.
(4) The airbag fabric according to any one of the above items 1 to 3, wherein the weaving shrinkage of the woven fabric yarn is 8% or more in total.
(5) The base fabric for an air bag according to any one of the above items 1 to 4, wherein the total fineness of the fabric constituting yarn is 200 to 420 dtex.
(6) An airbag formed by using at least a portion of the airbag fabric according to any one of 1 to 5 above.
(7) An airbag device comprising the airbag according to item 6 above.

  The air bag constituted by the base fabric of the present invention has less air and gas leakage under high pressure, and it is not necessary to unnecessarily increase the capacity of the inflator that supplies the inflation gas. In addition, high-pressure gas deployment has high reliability without bursting bag breakage. Furthermore, while being light and small when stored, the size when inflated is large, and a protective area for occupant protection can be secured. Therefore, it is excellent as a lightweight small airbag.

Hereinafter, the present invention will be described in detail.
The synthetic fiber used for the base fabric of the present invention is preferably a flexible and high-strength fiber suitable for a high-strength and high-density fabric. High-strength fibers are used for airbags that are hardly affected by the heat of explosives, such as stored gas inflators. Furthermore, in the case of an airbag that is deployed by an inflator using propellant, high-strength fibers and melt-resistant fibers are used.

  Polyamide fibers can be used as the melt resistant synthetic fibers. For example, polyamide 6/6 fibers mainly composed of polyhexamethylene adipamide fibers are preferable. The polyhexamethylene adipamide fiber refers to a polyamide 6.6 fiber having a melting point of 250 ° C. or higher composed of hexamethylene diamine and adipic acid. The polyamide 6.6 fiber used in the present invention has a melting point of less than 250 ° C. As long as this is not the case, polyamide 6, polyamide 6I, polyamide 610 and polyamide 6T may be copolymerized or blended.

As other synthetic fibers, polyester fibers can be used although the melt resistance is inferior. For example, a polyester fiber in which 90 mol% or more of the repeating units is ethylene terephthalate is preferable. It is also preferable to improve the flame retardancy of the polyester by containing a phosphorus compound. As components that can be copolymerized with ethylene terephthalate, both conventionally known acid components and glycol components can be mentioned. Among them, the flame retardancy of polyester is improved by copolymerizing a bifunctional phosphorus compound. It is preferable to pass an air bag combustion test.
Such fibers may contain various additives that are usually used for improving productivity or properties in the production process and processing process of the raw yarn. For example, a heat stabilizer, an antioxidant, a light stabilizer, a smoothing agent, an antistatic agent, a plasticizer and a flame retardant can be contained.

  The base fabric of the present invention preferably has a total fineness of constituent yarns constituting the woven fabric structure of 200 to 420 dtex. More preferably, it is 210 to 370 dtex, and particularly preferably 220 to 320 dtex. The greater the total fineness, the greater the tensile strength of the base fabric, which can contribute to the burst resistance of the airbag. On the other hand, the smaller the total fineness, the lighter the fabric.

The base fabric of the present invention is a lightweight base fabric, and the weight per unit area as a woven fabric (hereinafter referred to as basis weight) is preferably 200 g / m ² or less. More preferably, it is 185 g / m ² or less, more preferably 175 g / m ² or less, and most preferably 160 g / m ² or less. A minimum of 135 g / m ² is preferred for minimum mechanical properties. The base fabric of the present invention is basically a high-density woven fabric, and in order to reduce the basis weight, it can be reduced mainly by reducing the fineness of the constituent yarn.

  The base fabric of the present invention preferably has a tensile strength of 500 N / cm or more in the weft direction. More preferably, it is 550 N / cm or more, and more preferably 600 N / cm or more. The stronger the tensile strength, the more it can contribute to the burst resistance of the airbag. The elements that increase the tensile strength of the base fabric are the primary elements that the tensile breaking load (strength) of the constituent yarns of the fabric is large and the woven density is high. The tensile breaking load (strength) of the constituent yarn is determined by the size of the fineness and the tensile strength (strength). In addition, since the base fabric is required to have good storage properties, the upper limit of the tensile strength is preferably 900 N / cm in both the weft and backward directions because it is made of flexible synthetic fiber.

  In the constituent yarn of the base fabric of the present invention, the tensile strength is preferably 7.5 cN / dtex or more. More preferably, it is 8.5 cN / dtex or more, Most preferably, it is 9.5 cN / dtex or more. As a synthetic fiber that can constitute a high-quality and high-density fabric, the practical upper limit of the tensile strength as the constituent yarn is 11 cN / dtex.

The base fabric of the present invention preferably has a woven fabric cover factor of 2100 or more. More preferably, it is 2200 to 2500. Here, the cover factor ((via total fineness (dtex)) ^1/2 × Keio Density (present per 2.54 cm) + (weft total fineness (dtex)) ^1/2 × Nukio density (lines / 2. 54 cm)). The larger the cover factor, the higher the density fabric, and the higher the tensile strength of the base fabric.

  The base fabric of the present invention preferably has a tensile elongation at a load of 300 N / cm (hereinafter sometimes referred to as “intermediate elongation”) of 40% or more in total. The larger the elongation rate at a load of 300 N / cm is 40% or more in the weft direction, the larger the deployment size when the airbag is inflated by gas pressure, and the passenger protection area can be secured. Since the inflation rate is large, the size of the airbag at the time of folding and storing can be reduced while securing the passenger protection area during deployment. In addition, the amount of the development gas can be reduced in advance by considering the development size.

  The tensile elongation at a load of 300 N / cm can be increased mainly by increasing the wetting shrinkage in addition to the large tensile elongation of the constituent yarns. The weaving shrinkage rate is preferably 8% or more in total in the direction of the weft. More preferably, it is 10% or more, More preferably, it is 11% or more. In high-density fabrics, the upper limit of the woven shrinkage is 15%, for example, to prevent an increase in ventilation due to a tensile load. In the weaving design of the constituent yarn fineness and the weaving density, the finer the fineness, the larger the shrinkage rate tends to be, and the constituent yarn has a finer fineness, a high-density woven fabric, and an appropriate combination of textile processing methods. As a result, it is possible to obtain a base fabric having a large expansion coefficient without increasing the air permeability under a tensile load. In the base fabric composed of high strength fibers, the tensile elongation rate of the constituent yarn has a range as the physical properties of the high strength fiber that can be implemented, and the tensile elongation rate of the constituent yarn of the base fabric is preferably 15% to 35%. Since the tensile elongation rate as the base fabric is determined by the weaving shrinkage rate and the tensile elongation rate of the constituent yarns, the upper limit of the total background of the tensile elongation rate at a load of 300 N / cm of the base fabric is substantially 60%. is there.

  If the thermal relaxation processing is applied to the shrinkage of the synthetic fiber under the woven fabric processing conditions, the woven shrinkage rate increases. However, when the weaving shrinkage ratio is increased by free shrinkage processing, the air permeability increases due to the tensile load on the base fabric, which is inconvenient as a gas leak during high-pressure deployment. The air permeability after tensile loading of the base fabric can be suppressed by an appropriate method of heat-stretching the fabric.

  The base fabric of the present invention has an air permeability under a differential pressure of 50 kPa (referred to as “load seam air permeability” in the present specification) after applying a tensile load of 1,500 N / 15 cm to the seam in each of the longitudinal directions. The average air permeability after loading is 2000 mm / s or less. Here, the stitches are stitches of 15 cm at 50 times / 10 cm with a sewing thread which is a 1350 dtex twisted thread. The average of the air permeability after loading the seam of the base fabric should be small, and zero ventilation is desirable. However, if it is 2000 mm / s or less, the inflation rate of the base fabric can be fully utilized in deploying the airbag. Can be expanded greatly by making use of. More preferably, it is 1600 mm / s or less, More preferably, it is 1300 mm / s or less. It is possible to suppress the air permeability after tensile loading of the seam of the base fabric by appropriately combining the fabric processing methods, and it is advantageous to heat-treat the fabric. Furthermore, a higher weave density is advantageous, and a cover factor of 2100 or more is preferable. Moreover, the one where the single yarn fineness is narrow contributes to the suppression of ventilation after the seam load. It is advantageous for the weaving shrinkage of the constituent yarns to be small.

The base fabric of the present invention preferably has a maximum tensile resistance of 90 cN / dtex or more in total in the weft direction. Here, the tensile resistance R (cN / dtex) is a tangential gradient of the “load-elongation curve” in the tensile test, and is defined by the following equation.
R = F / (L ′ / L) / (d × D)
(Where F is the tensile load (cN / 2.54 cm) corresponding to the elongation rate of the tensile test, L is the tensile test length of the base fabric sample, and L ′ is the tangent of the “load-elongation curve” at the tensile load point. Is the sample elongation between two points from the intercept at the elongation axis to the intersection of the perpendicular drawn from the tensile load point to the elongation axis and the elongation axis, d is the total fineness (dtex) of the constituent yarn, and D is the weave density (Book / 2.54 cm)

  From the “load-elongation curve” obtained by the tensile test of the base fabric, the tensile resistance is obtained according to the elongation, and the “tensile resistance-elongation curve” is obtained. In the “tensile resistance-elongation curve”, the tensile resistance increases in accordance with the elongation (elongation), and reaches the fracture through the maximum value. Since the tensile resistance of the base fabric is large, gas leakage due to the high-pressure gas deployment of the airbag can be reduced. When the maximum tensile resistance in the “tensile resistance-elongation curve” in the weft direction of the base fabric is summed in the weft direction, and the total maximum tensile resistance is 90 cN / dtex or more, the gas utilization efficiency of the airbag is excellent. When the air bag is inflated and deployed, and the occupant enters and reaches the maximum pressure, the base fabric has a low elongation rate and gas leakage is suppressed. In particular, when deploying with propellant gas, the hot inflation gas tries to open the seam of the base fabric at the maximum pressure, and when the gas passes through the seam, it melts and breaks in the fine air bag. Therefore, it is important for the base fabric to have a high resistance to elongation in a high load region in order to prevent bag breakage. In addition, since the gas leak is small in the high load region, it contributes to increasing the development size. The maximum total tensile resistance is more preferably 98 cN / dtex or more, still more preferably 105 cN / dtex or more, and most preferably 120 cN / dtex or more. In order to bring the other physical properties of the base fabric into an appropriate range, the upper limit is 150 cN / dtex or less.

  In order to increase the maximum tensile resistance of the base fabric, it is contributed that the “load-elongation curve” of the constituent yarn is raised and the strength is high. The strength of the constituent yarn is preferably 7.5 cN / dtex or higher. As the strength of the constituent yarn increases, the maximum tensile resistance of the base fabric tends to increase. The maximum tensile resistance of the base fabric is the behavior of the resistance in the latter half of the “load-elongation curve” of the base fabric, which is close to the break. The degree will rise. Furthermore, the maximum tensile resistance of the base fabric is also affected by the base fabric processing. By a suitable method of heat tensioning the fabric, it can be maintained without reducing the maximum tensile resistance of the base fabric.

  In the present invention, the single fiber fineness of the synthetic fiber is preferably 0.5 to 8.0 dtex. More preferably, it is 0.8 to 7.0 dtex. More preferably, it is 1.0 to 4.0 dtex. If the single yarn fineness is 0.5 dtex or more, it is possible to avoid fabric defects and the like resulting from single yarn breakage in the weaving process and the like. The smaller the single yarn fineness is 8.0 dtex or less, the smaller the folded bulk of the fabric and the better the airbag storage. Furthermore, if it is 4.0 dtex or less, it contributes to the ventilation | gas_flowing suppression by the fabric surface by being thin.

  In the present invention, the boiling water shrinkage of the synthetic fiber yarn is preferably 10.0% or less, more preferably 8.0% or less, and further, the shrinkage force in the process of drying and heat setting of the fabric is expressed. By controlling the temperature, residence time, and tension, the boiling water shrinkage of the polyamide 6/6 fibers constituting the fabric can be suppressed to a low shrinkage of 5.0% or less. It is also preferable that the boiling water shrinkage of the synthetic fiber constituting the base fabric is completely shrunk. In the case of polyamide 6/6 fiber, it is also preferable that an apparently negative shrinkage rate, that is, elongation is observed by water absorption by the boiling water treatment, so the boiling water shrinkage rate of the yarn constituting the base fabric is minus 4.5% or more. It is preferable. The boiling water shrinkage is preferably minus 4.5 to 5.0%. More preferably, it is minus 4.0 to 3.0%, and further preferably minus 3.0 to 2.5%. On the other hand, the boiling water shrinkage of the synthetic yarn of the present invention is preferably 4% or more. More preferably 5% or more. More preferably, it is 6% or more. By utilizing the appropriate shrinkage force in the base fabric processing when the boiling water shrinkage of the synthetic fiber yarn is 4% or more, it contributes to the suppression of the air permeability after loading of the base fabric.

In the airbag fabric according to the present invention, the content of the oil component is preferably 0.01 to 2.0% by weight. More preferred is 0.05 to 1.5% by weight. More preferably, it is 0.1 to 0.7% by weight. An oil agent component here is what is extracted from a textile fabric with the organic solvent hexane, and is the percentage of the weight of the extract with respect to the weight of a synthetic fiber textile fabric. If the content of the oil component is 0.01% by weight or more, the tear strength of the woven fabric can be maintained and improved. If the content of the oil component is 2.0% by weight or less, the airbag fabric will not fail in the flammability test (FMVSS302).
These oil agent components may be derived from the process oil agent applied in the fiber manufacturing process and the weaving process.

  In addition to the above, as long as the effects of the present invention are not impaired, the woven fabric yarn contains various additives that are usually used for improving the productivity or characteristics in the raw yarn manufacturing process and processing process. It may be. For example, a heat stabilizer, an antioxidant, a light stabilizer, a smoothing agent, an antistatic agent, a plasticizer, a thickener, a pigment, a flame retardant, and the like can be included.

  In the base fabric of the present invention, the synthetic fibers can be woven by weaving with a water jet, air jet, rapier loom, multiphase loom or the like. As the woven fabric, plain woven fabric, twill woven fabric, satin weaving fabric, woven fabrics such as these modified woven fabrics, mixed woven fabrics, and multiaxial woven fabrics are used. Among these, particularly excellent mechanical properties and a thin surface are used. To plain fabric is preferred. Furthermore, the woven fabric which weaves a bag shape by bag weaving may be used.

In weaving, an oil component for improving the sizing property may be imparted to warps and the like. The oil agent component provided here may finally be contained in the airbag fabric.
Then, scouring can be performed to remove excess oil component and dirt. In the scouring process, alkali cleaning and surfactant cleaning are performed in a warm water bath. Rather, it is preferable to finish the airbag fabric without scouring. It is more preferable to finish a fabric for an airbag without scouring a fabric in which the oil component is generally removed by the water jet loom and the amount of the oil component attached is moderate. It is easy to control the amount of inclusions necessary for the present invention and is economical. Finally, it is preferable that a warping oil or a weaving process oil mainly composed of a smoothing agent and an antistatic agent is contained in the fabric as an oil component.

  In the scouring step, it is preferable to select an appropriate scouring temperature or not perform scouring. During scouring, it is preferable to control the amount of shrinkage and tension for the width of the fabric and the feed in the warp direction, respectively, and process while applying tension without leaving the fabric to shrink. The conditions may be appropriately selected according to the properties of the woven fabric yarn, particularly the shrinkage rate.

  Next, the woven fabric is dried and heat-set, so that it can be finished into a woven fabric for an air bag having good dimensional stability. In the drying and heat setting of the woven fabric, it is preferable to control the shrinkage and the tension with respect to the width of the woven fabric and the feeding in the warp direction. For example, a tenter is used. In order to suppress the air permeability after loading the base fabric, it is preferable to select the temperature of the heat treatment, and to perform the processing while applying a tension without contracting the heat treatment. The average shrinkage ratio of the woven fabric before and after processing is preferably 50% or less of the value of the boiling water shrinkage of the woven yarn used for weaving. More preferably, it is 40% or less. More preferably, it is 35% or less. That is, for example, the shrinkage rate during processing of the woven fabric is 6% or less, 4% or less, or 2% or less. Although it depends on the synthetic fiber used as the woven yarn, the average shrinkage of the background of the woven fabric before and after processing is preferably up to about −10%, that is, up to 10%. Subsequently, it is preferable to perform rapid cooling while applying tension after the heat treatment.

  The airbag fabric of the present invention may be coated with a resin or elastomer on the fabric to form a fabric. However, in order to reduce the weight of the airbag, the fabric may be used as it is without any resin or elastomer coating. preferable. The woven fabric may be finally calendered, but it is necessary not to cause a decrease in tearing strength, and it can be preferably used without calendering.

  The airbag fabric of the present invention is cut and sewn to provide a driver's seat airbag, a passenger seat airbag, a rear seat airbag, a side airbag, a knee airbag, an inter-car seat airbag, and a side airbag. It can be suitably used for a curtain air bag, a rear window curtain bag, a pedestrian protection airbag, and the like. Furthermore, in the airbag, a reinforcing fabric used for an inflator attachment port, a vent hole portion, or the like, or a member that regulates a bag deployment shape can be the same base fabric as the airbag fabric. In the sewing of the airbag, one or a plurality of such airbag fabric pieces formed by punching, fusing, or cutting can be used to sew the peripheral portion to form the airbag. Can form an airbag in which the peripheral portion is sewn in a single or double line.

Moreover, the base fabric for airbags of this invention is woven as a bag textile, and the outer periphery of a connection part is cut | judged and it can be used as an airbag.
The airbag module of the present invention can be made into an airbag module in combination with the above-described airbag and an inflator using a gunpowder or propellant that is a gas generator or an inflator using a high-pressure gas cylinder.

Next, the present invention will be described in more detail with reference to examples and reference examples.
About the characteristic evaluation of the base fabric for airbags in an Example, it implemented by the following method.
(1) Fabric weight: (g / m ² )
The measurement was performed according to JIS L1096: 2010 8.3.2 A method using a 10 cm × 10 cm sample.

(2) Total fineness of constituent yarns: (dtex)
JIS L1096: 2010 Annex H. The base fabric was disassembled according to No. 7, and the sample length was measured with respect to the constituent yarns of the background as 25 cm. Even if it was a coated fabric, the base fabric was disassembled and the constituent yarn was taken out.

(3) Tensile strength of constituent yarn: (cN / dtex)
According to the tensile strength evaluation method of JIS L1013: 2010 8.5.1, twisting was performed 10 times / 10 cm, and a tensile test was performed at a grip interval of 25 cm and a pulling speed of 30 cm / min.
(4) Number of constituent yarn filaments:
The number of constituent single yarns was counted from a cross-sectional photograph of the base fabric.

(5) Fabric cover factor (CF):
It calculated | required from the following formula | equation.
CF = (Dw) ^1/2 * Tw + (Df) ^1/2 * Tf
(Where Dw is the total fineness (dtex) of the constituent yarns in the warp direction, Df is the total fineness (dtex) of the constituent yarns in the weft direction, Tw is the warp weave density (main / 2.54 cm), Tf is the weft weave density ( Book / 2.54 cm).)

(6) Tensile strength and elongation of base fabric:
JIS L1096: 2010 8.14.1 a) In method A (strip method), a sample of 30 mm × 340 mm was taken by a labeled strip method, and a low-speed extension tensile test was performed at a grip interval of 200 mm at 200 mm / min. The base fabric tensile strength (N / cm) was determined by evaluating the tensile strength of the base fabric. For the intermediate elongation (%), the elongation at 300 N / cm load was obtained for each of the warp direction and the weft direction in the obtained “load-elongation curve”. Furthermore, the tangential slope of the “load-elongation curve” was calculated, and the tensile resistance (cN / dtex) obtained by dividing the tangential slope by the woven fineness (ie, constituent yarn fineness × woven density) was drawn according to the elongation rate. "Tensile resistance-elongation curve" was obtained, and the maximum tensile resistance (cN / dtex) was determined. The maximum tensile resistance in each of the warp and weft directions was added to obtain the total maximum tensile resistance.

(7) Woven density:
JIS L1096: 2010 Annex FA. 2 Performed according to Method E (tapered densimeter).
(8) Weaving shrinkage rate: (%)
It implemented by JISL1096: 20108.7B method.

(9) Coating amount: (g / m ² )
A 10 cm square test piece is accurately taken from the base fabric, cut into approximately 5 mm squares or less, washed with hexane twice at 25 ° C. for 5 minutes, air dried and then dried at 105 ° C. for 12 hours with a hot air dryer. . The synthetic fiber is dissolved with a solvent. If it is a polyamide fiber, it melt | dissolves at room temperature overnight using 250 ml of 90% formic acid, and filter-separates the crosslinked silicone membrane which does not melt | dissolve. The silicone membrane separated by filtration is thoroughly washed with a solvent, washed with water, dried in hot air at 105 ° C., and the absolutely dry mass w (g) is measured. The coating amount (g / m ² ) is determined from (w / 0.01). In addition, a method is also possible in which the silicone film is dissolved with a silicone dissolving agent, and the remaining synthetic fiber fabric is filtered to obtain the coating amount.

(10) Load seam permeability (air permeability at the boundary between the inflated part and the non-inflated part): (mm / s)
Cut out two sample base fabrics of 28cm in length x 15cm in width. If it is a coated fabric, the coated surfaces face each other, take 1cm of seam allowance from the side, and 50 times / 10cm with sewing thread that is 1350dtex twisted yarn Sewing along the horizontal side in the main stitch, that is, 15 cm of sewing is performed, and both ends of the sewing thread are tied. Thereafter, in a tensile tester manufactured by A & D, a load of 1500 N was applied to the stitches at a speed of 100 mm / min, and then removed once and the dynamic air permeability was measured after 10 hours. The dynamic air permeability was measured using FX3350 manufactured by TEXTEST, with a filling pressure of 300 kPa and a filling capacity of 400 cc, and the air permeability (mm / s) at 50 kPa was measured.

(11) Airbag bag making:
The airbag was sewn according to the description in WO99 / 28164. In the case of a coated cloth, the front and back panel cloths were stitched with the coated surfaces facing each other. However, the outer periphery sewing was a two-row double chain stitch with a sewing thread of 235 dtex / 2 × 3 and a number of stitches of 5.0 stitches / cm. There was no vent hole. A retainer provided with a gas inlet was inserted into the obtained airbag.

(12) Expanded size ratio:
Using the airbag described in the above item (11), 50 kPa was applied with compressed air, and the deployment sizes were compared. The state of the bag development was observed from the front, and the maximum value of the outer shape of the bag was obtained. The maximum projected area of the outer shape in Comparative Example 1 to be described later was set to 100, the relative projected area ratio was determined, and the developed size ratio was obtained.

(13) Seal burst pressure: (kPa)
In the airbag of the above item (11), a vent hole was not provided, and the sewing part sandwiched a sealing agent between the base fabrics. At the sewing position, a double-sided adhesive sticker was applied in a band shape with a width of 8 mm and sandwiched between base fabrics. However, in the case of the coated base fabric, an adhesive seal was affixed to the coated surface side, and the adhesive seal was sandwiched between the base fabrics. For the adhesive seal, use is made of an acrylic resin foam as the flexible base material and a silicone-based adhesive applied on both sides thereof (double-sided adhesive heat-resistant product of Sumitomo 3M adhesive tape GT7112, thickness 1.2 mm) It was. Next, the cut pieces were overlapped and pressure-bonded with a roller having a weight of 6 kg with an adhesive seal interposed therebetween. The stitching position was the center along the band of the adhesive seal. In addition, a gas pressure sensor was attached to the center of the bag. After installing the airbag in an airbag deployment device (Cold Gas Systems; manufactured by Microsys Technologies Inc.) and inflating the airbag with compressed air of about 30 kPa, 12 L of compressed air charged in a 1 L tank was put into the airbag. The bag burst pressure was measured.

(14) Inflator burst:
The airbag according to the above item (11), which does not have a vent hole, has a pyro type inflator, and has an output of 28.3 L tank pressure of 210 kPa. The presence or absence of airbag breakage (burst) was observed.
○: With broken bag (burst) ×: Without broken bag (burst)

[Example 1]
A filament yarn of polyamide 6/6 fiber was used which had a fineness of 235 dtex, a filament count of 72, a tensile strength of 10.0 cN / dtex, and a boiling water shrinkage of 7.0%. The woven yarn was woven with a water jet loom without twisting and without gluing to obtain a plain woven fabric. Without scouring the obtained woven fabric, it was dried with hot air at 80 ° C., then, using a pin tenter, the weft direction was 2.5% widening, and the warp direction was 2.5% overfeed at 180 ° C. After heating for a minute, it was heat-set by quenching with tension. Table 1 shows the characteristics of the obtained airbag fabric. The elongation at a load of 300 N / cm is large, and the tensile resistance is also large.
It has been found that the deployment size of the airbag with cold gas is larger than that of the airbag made of 470 dtex fibers shown in Comparative Example 1. Moreover, the influence of the gas leak in cold gas deployment is not seen, and the burst pressure of a seal bag is also high. No burst due to inflator expansion was observed. These evaluation results are also shown in Table 1.

[Example 2]
The heat setting after weaving was carried out in the same manner as in Example 1 except that the weft direction was not inserted in the weft direction and the width dimension change was 0%, and the warp direction was 4.0% overfeed. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. The processing is performed under slightly relaxed conditions, the intermediate elongation of the base fabric is slightly increased, and the development size is large. In addition, there are few cold gas leaks, and there is no bag burst even when the inflator is deployed.

[Example 3]
The same procedure as in Example 1 was conducted except that a woven yarn having a fineness of 300 dtex, a tensile strength of 8.8 cN / dtex, and a boiling water shrinkage of 7.0% was woven. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. Although the base fabric tensile strength is large, the intermediate elongation of the base fabric is slightly reduced, and the development size is sufficient but slightly small. On the other hand, there is no influence of leak of cold gas deployment, and the burst pressure of the seal bag is high. Moreover, there is no bag burst by inflator deployment.

[Example 4]
The heat setting after weaving and scouring was performed in the same manner as in Example 3 except that the weft direction was 3.0% in the width direction and 1.5% in the warp direction was the overfeed. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. The processing becomes under tension and tension, the intermediate elongation of the base fabric is slightly reduced, and the unfolded size is sufficient but slightly smaller. On the other hand, there is no influence of leak of cold gas deployment, and the burst pressure of the seal bag is high. Moreover, there is no bag burst by inflator deployment.

[Example 5]
The heat setting after weaving and scouring was carried out in the same manner as in Example 3 except that the width direction was changed to 0% without adding the width and the warp direction was set to 4.0% overfeed in the warp direction. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. The processing is performed under slightly relaxed conditions, the intermediate elongation of the base fabric is slightly increased, and the development size is large. There is no gas leak effect from cold gas deployment. In addition, although the tensile resistance of the base fabric is slightly reduced, there is no bag burst even when the inflator is deployed.

[Example 6]
Oil was added at 1.5% during aging, weaving in the same manner as in Example 1, heat setting without scouring, and coating with a liquid addition reaction type silicone elastomer at 20 g / m ² knife. Vulcanization was carried out at 200 ° C. for 30 seconds with 1% widening and 1% overfeed. The basis weight of the woven fabric was 145 g / m ² , the coating amount was 20 g / m ² , and the basis weight of the entire airbag fabric including the coating was 165 g / m ² . Table 1 shows the characteristics and evaluation results of the obtained airbag fabric.
The deployment size is large, there is no gas leak effect in the cold gas deployment, and there is no bag burst even in the inflator deployment.

[Comparative Example 1]
A filament yarn of polyamide 6.6 fibers was used, which had a fineness of 470 dtex, a filament count of 72, a tensile strength of 8.3 cN / dtex, and a boiling water shrinkage of 7.0%. The woven yarn was woven with a water jet loom without twisting and without gluing to obtain a plain woven fabric. Without scouring the obtained woven fabric, it was dried with hot air at 80 ° C., then, using a pin tenter, the weft direction was 4.0% widening, and the warp direction was 4.0% overfeed at 180 ° C. After heating for a minute, it was heat-set by quenching with tension. Table 1 shows the characteristics of the obtained airbag fabric.
The base fabric strength is high and the burst pressure of the seal bag is high enough. There was no bag burst even in the inflator deployment. However, since the weight of the base fabric is heavy and the intermediate elongation is small, the bag deployment size is small. These evaluation results are also shown in Table 1.

[Comparative Example 2]
A filament yarn of polyamide 6 · 6 fiber, having a fineness of 235 dtex, a filament count of 72, a tensile strength of 8.3 cN / dtex, and a boiling water shrinkage of 7.0% was used. Weaving was performed as in Example 1, and heat setting was performed under the conditions of no width in the weft direction with a width dimension change of 0% and over warping in the overfeed of 4.0%. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. The processing conditions are relaxed and the intermediate elongation of the base fabric is large, but the air permeability is increased. Small size due to gas leak. Moreover, the burst pressure of the seal bag is low due to insufficient tensile strength of the base fabric. Even inflator deployment burst.

[Comparative Example 3]
The heat setting after weaving was carried out in the same manner as in Comparative Example 2 except that the weft direction was 2.5% widening and the warp direction was 2.5% overfeed. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. Although the intermediate elongation of the base fabric is large, there is a gas leak and the development size is small. With the seal bag deployed, the burst pressure is appropriate. However, the tensile resistance was low and the inflator deployment burst from hot gas leaks.

[Comparative Example 4]
A filament yarn of polyamide 6/6 fiber was used having a fineness of 235 dtex, a filament count of 72, a tensile strength of 10.0 cN / dtex, and a boiling water shrinkage of 4.0%. Weaving was performed as in Example 1, and heat setting was performed under the conditions that the weft direction did not include a width and the width dimension change was 0%, and the warp direction did not overfeed and the fabric length change was 0%. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. The intermediate elongation of the base fabric is small, and the bag deployment size is small. On the other hand, in the burst burst deployment, there was no gas leak effect and the burst pressure was high. There was no bag burst in the inflator deployment.

[Comparative Example 5]
The heat setting after weaving was carried out in the same manner as in Example 1 except that the weft direction was 4.0% with width insertion and the warp direction was 4.0% with overfeed. Table 1 shows the characteristics and evaluation results of the obtained airbag fabric. Although the processing conditions are relaxed and the intermediate elongation of the base fabric is large, the air permeability is high and the development size is small. Moreover, in the burst burst deployment, there was no gas leak effect and the burst pressure was high. Inflator deployment burst from a hot gas leak.

  The present invention is suitable for a vehicle, that is, an airbag that is mounted on a vehicle and used for passenger safety and pedestrian safety.

Claims (7)

  Made of synthetic fiber fabric, tensile strength in tensile test is 500 N / cm or more in the longitudinal direction, elongation at 300 N / cm load is 40% or more in the longitudinal direction, and maximum tensile resistance is the total in the longitudinal direction 90 cN / dtex or more, and the load seam air permeability (the air permeability under a differential pressure of 50 kPa after applying a tensile load of 1,500 N / 15 cm to a specific seam) is the air permeability after loading in the longitudinal direction. An air bag base fabric having an average of 2000 mm / s or less. ^{2. The} airbag fabric according to claim 1, wherein the fabric weight is 200 g / m < ² > or less.   The base fabric for an air bag according to claim 1 or 2, wherein the cover factor of the woven fabric is 2100 or more.   The base fabric for an air bag according to any one of claims 1 to 3, wherein the weaving shrinkage of the woven constituent yarn is 8% or more in total.   The base fabric for an airbag according to any one of claims 1 to 4, wherein the total fineness of the woven fabric constituent yarn is 200 to 420 dtex.   The airbag formed using the base fabric for airbags as described in any one of Claims 1-5 at least partially.   An airbag device comprising the airbag according to claim 6.