Airbag base fabric and airbag

Abstract

Provided is a resin-coated airbag woven base fabric that does not readily burst because of ruptures from parts where stress has concentrated. The present invention relates to an airbag woven base fabric that is resin-coated on at least one side and an airbag produced by sewing the airbag woven base fabric. The average value in the warp and weft directions of a notch tensile strength N1 (N) obtained when a test piece of the woven base fabric that has been notched at a center part is held at both ends and subjected to tensile testing is 1100–3000.

Description

Airbag base fabric and airbag

[0001] This invention relates to a base fabric for an airbag that constitutes an airbag (cushion) used in an airbag system for mitigating the impact on the human body in collision accidents such as those involving automobiles.

[0002] As a device to mitigate the impact on the human body in collisions involving vehicles such as automobiles, the installation of airbags in vehicles is progressing. In addition to driver's and passenger's side airbags, airbags such as curtain airbags, side airbags, knee airbags, and rear airbags are being installed in vehicles to protect occupants, as they inflate with gas during a collision to absorb and mitigate the impact on the human body. Furthermore, for pedestrian protection, airbag devices consisting of airbag cushions that inflate outside the vehicle's passenger compartment (pedestrian airbags) and far-side airbag devices consisting of airbag cushions that restrict occupants seated on the opposite side of the collision from moving towards the collision side during a side collision on the opposite side from where the car seat is installed (far side) have been proposed.

[0003] The airbags (cushions) in these airbag systems are normally folded and stored away. When a sensor detects the impact of an accident, the airbags (cushions) deploy and inflate. The gas generated by the inflator pushes the folded airbags out, breaking through the cover of the storage area, and the airbags (cushions) pop out. Once fully inflated, they catch the person's body.

[0004] In recent years, airbag systems have become larger and more complex in shape to accommodate a wide range of collision conditions. They need to mitigate the impact of collisions from various positions and for occupants of varying body types and postures. To address this wide range of collision conditions, it is necessary to increase the deployment speed of the airbag and raise the internal pressure to absorb collision energy. As the size of the airbag cushion increases, the volume of the airbag inflation chamber also tends to increase. To instantly raise the internal pressure of a large-capacity airbag, the output of the inflator (generated gas) needs to be increased. However, when a folded airbag inflates while deploying, inflation pressure is concentrated in specific areas, potentially causing the base fabric to rupture at these stress points and leading to a decrease in internal pressure.

[0005] To accommodate a wider range of collision conditions, the shape of airbags needs to be more complex, and pedestrian airbags and all-around airbags may have highly asymmetrical designs. In addition, driver's side airbags are expected to be stored not only in the conventional circular steering wheel, but also in irregularly shaped steering wheels and other highly asymmetrical spaces, and for this purpose, the bag design may also be highly asymmetrical. With highly asymmetrical airbag shapes, there is a concern that when the airbag inflates, an unintended stress imbalance may occur on the base fabric, causing stress concentration in specific areas, which could lead to the base fabric rupturing and a decrease in internal pressure.

[0006] Patent Document 1 below proposes a coated fabric using yarn with a total fineness of 67 to 350 dtex. While improved deployment performance is expected due to the small difference in warp and weft friction coefficients, and deployment performance has been evaluated for highly symmetrical airbags such as driver's side airbags, the document does not address airbags with highly asymmetrical shapes where differences in load distribution on the base fabric occur during testing.

[0007] Patent Document 2 below proposes a silicone-coated base fabric that exhibits minimal seam misalignment and excellent mechanical properties (tensile strength, tear strength, etc.). While improved resistance to seam misalignment is expected to suppress gas leakage from seam openings, the document does not address the issue of base fabric rupture in airbags with highly asymmetrical shapes where differences in load distribution on the base fabric occur during testing.

[0008] Japanese Patent Publication No. 2006-249655, International Publication No. 2016-158858

[0009] In view of the aforementioned level of prior art, the problem that the present invention aims to solve is to provide a resin-coated woven fabric base for airbags that is less prone to bursting due to rupture from stress-concentrated base fabric portions.

[0010] In order to solve the aforementioned problems, the inventors diligently conducted research and experiments, and as a result, unexpectedly discovered that a woven base fabric for airbags having the following characteristics could solve the aforementioned problems, thus completing the present invention.

[0011] In other words, the present invention is as follows: [1] A woven fabric base for airbags, wherein at least one side is coated with resin, and when a tensile test is performed by grasping both ends of a test piece with a notch made in the center of the woven fabric base, the average value of the notch tensile strength N1(N) in the warp and weft directions is 1100 or more and 3000 or less. [2] The woven fabric base for airbags according to [1], wherein the average value of the tensile strength utilization rate N2(-), which is the value obtained by dividing the notch tensile strength N1(N) by the tensile strength (N), in the warp and weft directions is 0.50 or more and 0.95 or less. [3] The amount of resin coating applied to the woven fabric base is 5 g / m ２ 30g / m or more ２The following are the airbag fabrics described in [1] or [2] above: [4] The airbag fabric according to any one of [1] to [3] above, wherein the stiffness of the fabric in the warp and weft directions is 60 mm or more and 100 mm or less. [5] The airbag fabric according to any one of [1] to [4] above, wherein the warp and weft density ratio of the fabric is 0.95 or more and 1.05 or less. [6] The airbag fabric according to any one of [1] to [5] above, wherein the slip resistance of the fabric in the warp and weft directions is 300 N or more and 1500 N or less. [7] The airbag fabric according to any one of [1] to [6] above, wherein the strength of the fabric in the warp and weft directions is 350 N / cm or more and 1000 N / cm or less. [8] The woven fabric base for airbags according to any one of [1] to [7], wherein the elongation in the warp and weft directions of the woven fabric base is 20% or more and 40% or less in both directions. [9] The woven fabric base for airbags according to any one of [1] to [8], wherein the fibers constituting the woven fabric base are made of nylon 66 or polyethylene terephthalate.

[10] The woven fabric base for airbags according to any one of [1] to [9], wherein the viscosity of the resin coating agent applied to the woven fabric when applied to the fabric is such that when the viscosity measured at 20°C is A and the viscosity measured at 30°C is B, the value obtained by dividing A by B is 1.05 or more and 1.30 or less.

[11] The woven fabric base for airbags according to any one of [1] to

[10] , wherein the cross-section of the single fibers constituting the woven fabric base is circular.

[12] An airbag made by sewing the woven fabric base for airbags according to any one of [1] to

[11] .

[13] The airbag according to

[12] having a tether.

[14] The airbag according to

[12] or

[13] , which is a side curtain airbag.

[15] The airbag according to

[12] or

[13] , which is a pedestrian airbag.

[16] The airbag according to

[12] or

[13] , which is a far side airbag.

[0012] By sewing the woven base fabric for airbags according to the present invention to produce an airbag (cushion), tearing of the base fabric becomes less likely even in airbags with highly asymmetrical shapes. Therefore, a woven base fabric for airbags suitable for pedestrian airbags and far-side airbags can be provided.

[0013] This is an explanatory diagram of a sample used for notch tensile strength measurement. This is an explanatory diagram of the airbag shape during burst testing. This is an explanatory diagram of the burst testing equipment. This is an explanatory diagram of the airbag shape during complex-shaped burst testing. This is an explanatory diagram of the complex-shaped burst testing equipment. This is an electron microscope image and Si element mapping of a cross-section of a sample. This is a cross-sectional view for calculating permeability. This is a cross-sectional view for calculating coating thickness.

[0014] The embodiments of the present invention will be described in detail below, but the present invention is not limited to these embodiments and examples, and can be modified as appropriate without departing from the spirit of the invention and the scope of equivalents.

[0015] One embodiment of the present invention is a woven fabric base for airbags, in which at least one side is coated with resin, and the average value of the notch tensile strength N1 (N) obtained when a tensile test is performed by grasping both ends of a test piece with a notch made in the center of the woven fabric base is 1100 to 3000 in the weft direction.

[0016] In the woven fabric base for airbags of this embodiment, the average value of the notch tensile strength N1 (N) obtained when a tensile test is performed by grasping both ends of a test piece with a notch made in the center of the woven fabric base is 1100 or more and 3000 or less in the warp and weft directions, preferably 1300 to 2500, and more preferably 1500 to 2200. If the average value of N1 in the warp and weft directions is 1100 or more, it becomes an airbag base that suppresses rupture from the stress-concentrated base fabric portion, and if it is 3000 or less, sufficient flexibility as an airbag base is obtained, and it becomes a base that is less likely to burst even under instantaneous high pressure.

[0017] The inventors of this invention have diligently researched methods for controlling the penetration of the coating resin into the base fabric and have found that by achieving an appropriate level of penetration, the notch tensile strength (N) can be unexpectedly increased without drastically improving tensile strength or slip resistance. The notch tensile strength can be controlled by appropriately setting the adhesion and slippage between the fibers (yarns) that make up the base fabric. To achieve appropriate adhesion between yarns, it is effective to cover the outer circumference of the yarn with a silicone agent, so that the yarns stick together and the stress can be borne by the entire yarn. Furthermore, it is effective that the silicone does not penetrate into the inside of the yarn, resulting in a flexible yarn that deforms and easily adheres to adjacent yarns. On the other hand, to achieve appropriate slippage between yarns, it is effective that the silicone penetrates appropriately into the yarn contact area. The yarn contact area here refers to the region inside the fabric where the warp and weft threads intersect vertically and overlap and come into contact with each other, and refers to the middle layer structure centered on the intersection point that is responsible for load transmission and frictional behavior between the threads. To increase the notch tensile strength, it is also effective to utilize stress distribution in the silicone layer. Typically, the silicone agent applied to a woven fabric base is thicker at the intersections than at the center of the floating areas. However, by reducing the thickness difference between the silicone layer at the intersections and the center of the floating areas, stress distribution in the silicone layer can be efficiently achieved. Here, the intersections refer to the points in a woven fabric where warp and weft threads intersect vertically, and floating refers to the portion of yarn exposed on the surface between adjacent intersections. The optimal penetration conditions for the coating resin vary depending on the material, fineness, and cover factor of the fibers constituting the woven fabric base. However, the inventors of this invention have found that, for example, by using a resin with temperature-dependent viscosity and precisely controlling the liquid temperature during coating, the fabric temperature, and the tenter temperature during resin curing, it is easier to manufacture a woven fabric base with the desired notch tensile strength. Furthermore, adjusting the weaving tension and washing temperature was found to be effective in controlling the penetration of the silicone agent into the yarn.

[0018] When an airbag is manufactured by sewing the woven fabric base for airbags according to this embodiment, the average value of the tensile strength utilization rate N2(-), which is the value obtained by dividing the notch tensile strength N1(N) of the woven fabric base by the average value of the tensile strength (N) in the warp and weft directions, is preferably 0.50 or more and 0.95 or less, more preferably 0.60 to 0.93, and even more preferably 0.70 to 0.80. It is possible to increase the notch tensile strength of the woven fabric base by using a high-strength yarn such as aramid fiber as the yarn used, but if a high-strength yarn is used, the manufacturing cost will increase significantly and it will not be practical. It is also possible to increase the notch tensile strength by increasing the fineness of the yarn used, but in this case it is difficult to achieve both compactness and burst resistance. If N2(-) is 0.50 or higher, the load on the base fabric can be distributed over a wider area, resulting in a higher utilization rate of tensile strength. This prevents rupture from stress-concentrated areas of the base fabric without increasing the tensile strength, i.e., without increasing the fineness of the fibers constituting the base fabric, thus enabling the creation of a compact and highly burst-resistant airbag. Furthermore, it has been found that, especially with complex bag shapes, the more the tensile behavior differs between areas prone to stress concentration and areas not prone to stress concentration, the more drastically the burst pressure resistance tends to decrease. As a result of diligent research by the inventors of this application, it has been found that increasing N2 to 0.50 or higher prevents rupture from stress-concentrated areas of the base fabric, even in bags with very complex shapes. This is thought to be because N2 being 0.50 or higher brings the tensile behavior at stress concentration points and non-stress concentration points closer together, preventing the decrease in burst pressure exacerbated by the difference in the degree of stress concentration. The notch tensile strength N1 (N) (see Figure 1(B)), which is the tensile strength when a notch is made in the center of a sample used for tensile strength measurement, is theoretically difficult to make greater than the value of the normal tensile strength (N), and therefore cannot be greater than 1.00.

[0019] The tensile strength (N / cm) of the woven fabric base for airbags, in this embodiment, which has at least one side coated with resin, is preferably 350 N / cm or more in both the warp and weft directions, more preferably 400 N / cm or more, and even more preferably 500 N / cm or more. There is no particular upper limit to the tensile strength.

[0020] The fibers constituting the woven fabric base of this embodiment are not particularly limited, but examples include polyamide fibers, polyester fibers, polyolefin fibers, chlorine-containing fibers, fluorine-containing fibers, polyacetal fibers, polysulfone fibers, polyphenylene sulfide fibers (PPS), polyetheretherketone fibers (PEEK), all-aromatic polyamide fibers, all-aromatic polyester fibers, polyimide fibers, polyetherimide fibers, poly(p-phenylenebenzbisoxazole) fibers (PBO), vinylon fibers, acrylic fibers, cellulose fibers, silicon carbide fibers, alumina fibers, glass fibers, carbon fibers, steel fibers, etc. From the viewpoint of melting point, heat capacity, strength, specific gravity, cost, etc., polyamide fibers or polyester fibers are more preferred. Furthermore, these fibers may contain various additives that are normally used to improve productivity and properties in the manufacturing and processing processes of the raw yarn. For example, these fibers may contain heat stabilizers, antioxidants, light stabilizers, smoothing agents, antistatic agents, plasticizers, thickeners, pigments, flame retardants, and the like.

[0021] The total fineness of the fibers constituting the woven base fabric may be 230 dtex or more and 1200 dtex or less, more preferably 300 to 900 dtex, and even more preferably 400 to 800 dtex. If the total fineness is 230 dtex or more, the necessary mechanical properties (tensile strength, sewing strength, etc.) can be obtained. On the other hand, if the total fineness is 1200 dtex or less, the thickness of the base fabric will not become too large, and flexibility and compactness can be satisfied.

[0022] The single fiber fineness of the fibers constituting the woven base fabric is preferably 1.0 dtex or more and 8.0 dtex or less, more preferably 1.5 to 7.0 dtex, and even more preferably 2.0 to 4.0 dtex. In the case of polyamide fibers, setting the single fiber fineness to 1.0 dtex or more suppresses single fiber breakage during manufacturing and makes manufacturing easier. Furthermore, setting the single fiber fineness to 8.0 dtex or less improves the flexibility of the resulting warp and weft threads. As a result, the resulting airbag tends to be more compact. In particular, if the single fiber fineness is within the above preferred range, the voids between single fibers in the fabric tend to be smaller. As a result, the degree of adhesion between the warp and weft threads can be increased, and the resistance to shear resistance can be improved. The single fiber fineness can be calculated by dividing the total fineness by the number of filaments. The number of filaments can be calculated based on the method of JIS L1013 (2010) 8.4.

[0023] The cross-sectional shape of the single fibers constituting the woven base fabric is not particularly limited. For example, the cross-sectional shape of the single fiber may be circular, or it may be various non-circular shapes such as Y-shaped, V-shaped, or flattened, or it may have a hollow portion. Among these, the cross-sectional shape of the single fiber is preferably circular from the viewpoint of yarn production. A circular shape is defined as a value obtained by dividing the circumscribed circle diameter of the cross-section of the single fiber by the inscribed circle diameter of 1.0 or more and 1.3 or less.

[0024] The tensile strength of the fibers constituting the woven base fabric should be 7.0 cN / dtex or higher, and preferably 8.0 cN / dtex or higher. If the tensile strength is less than 7.0 cN / dtex, the resulting base fabric will not easily acquire sufficient mechanical properties (tensile strength, tear strength, etc.). There is no particular upper limit to the tensile strength. When considering the productivity of polyamide fibers, the upper limit of the tensile strength can be adjusted to about 10.0 cN / dtex. The tensile strength can be calculated by measuring it under the constant-rate elongation conditions shown in JIS L1013 (2010) 8.5.1 Standard Time Test.

[0025] The elongation of the fibers constituting the woven base fabric is preferably 18% or more, and more preferably 20% or more. Furthermore, the elongation is preferably 25% or less, and more preferably 24% or less. When the elongation of the polyamide or polyethylene terephthalate fibers is within the above range, the resulting fabric will have excellent toughness and work of breaking. In addition, polyamide or polyethylene terephthalate fibers exhibiting elongation within the above range may have improved spinnability and weaving properties. The elongation can be calculated based on the elongation at the point showing the maximum strength in the S-S curve obtained when calculating the tensile strength.

[0026] The aforementioned woven base fabric can be any fabric with a structure such as plain weave, check weave, or twill weave, and can be woven using existing air jet looms, water jet looms, rapier looms, multiphase looms, etc., and there are no particular restrictions on the weaving method. Using a water jet loom is preferable because it can remove oils adhering to the yarn, thereby improving the adhesion of the resin.

[0027] When weaving the aforementioned woven fabric, the weaving tension of the warp threads is preferably 50 cN / thread or more and 200 cN / thread or less, and more preferably 70 cN / thread or more and 150 cN / thread or less. In a woven fabric produced with a warp thread weaving tension of 50 cN / thread or more, the fibers constituting the woven fabric are woven in a state where the filaments constituting the yarn are sufficiently aligned with each other. By applying a resin coating to this woven fabric, it is possible to make it difficult for the resin to penetrate into the inside of the yarn and easy for it to penetrate to the outside of the yarn, thereby making it easier to achieve the desired penetration state.

[0028] It is preferable that the water temperature when washing the woven fabric base fabric with water is 30 to 40°C in the first tank, 40 to 50°C in the second tank, and 50 to 60°C in the third tank. When the water washing temperature of each tank is equal to or higher than the above temperature, the oil agent adhering to the outer side of the yarn can be sufficiently removed, the adhesion of the resin is improved, and furthermore, the fibers constituting the woven fabric form a favorable crimp shape due to heat shrinkage. On the other hand, when the water washing temperature of each tank is equal to or lower than the above temperature, it is possible to achieve a state where more oil agent is removed from the outside of the yarn than from the inside of the yarn constituting the woven fabric base fabric. By applying a resin coating to this woven fabric base fabric, it is difficult for the resin to penetrate into the inside of the yarn and easy to penetrate into the outside of the yarn, making it easy to achieve a desired penetration state.

[0029] The woven fabric base fabric for an airbag according to the present embodiment is one in which at least one side of the woven fabric is coated with a resin. By coating at least one side of the woven fabric with resin, air barrier properties are imparted to the woven fabric base fabric. In addition, even when high-temperature gas is generated from an inflator during deployment of the airbag, the woven fabric having at least one side (particularly the one side disposed on the inner surface side of the airbag) coated with resin is easily protected from heat.

[0030] The type of coating resin is not particularly limited. Examples of the coating resin include polyamide resins, polyurethane resins, and silicone resins. Among these, it is preferable that the woven fabric base fabric is coated with a silicone resin. Thereby, the woven fabric base fabric can obtain more excellent heat resistance, cold resistance, flame retardancy, air barrier properties and the like. Examples of the silicone resin include dimethyl-based silicone resins, methyl vinyl-based silicone resins, methyl phenyl-based silicone resins, and fluoro-based silicone resins.

[0031] Furthermore, the coating resin preferably contains a flame retardant compound. Examples of the flame retardant compound include halogen compounds containing bromine, chlorine and the like. Specifically, examples of the flame retardant compound include halogenated cycloalkanes, platinum compounds, antimony oxide, copper oxide, titanium oxide, phosphorus compounds, thiourea-based compounds, carbon, cerium, and silicon oxide. Among these, halogen compounds, platinum compounds, copper oxide, titanium oxide, and carbon are preferable as the flame retardant compound.

[0032] The viscosity of the resin when applied to the woven fabric is preferably 5 to 60 Pa·s (5,000 to 60,000 cP) so that a stable and constant amount can be easily applied to the woven fabric. The resin may originally be a solvent-free type exhibiting such a viscosity, or may be a solvent type appropriately diluted with a solvent to achieve such a viscosity. Among these, solvent-free resins are preferable from the viewpoints of excellent workability and low environmental load. The viscosity of the resin can be measured in an environment at 20°C using a rheometer based on ISO 3219. If the viscosity of the resin is 5 Pa·s (5,000 cP) or more, it is easy to apply the target coating amount during a coating operation (for example, a resin coating operation by a knife coating method), and strike-through is less likely to occur. On the other hand, if the viscosity of the resin is 60 Pa·s (60,000 cP) or less, the coating does not become excessively thick, and a base fabric with suitable storability can be obtained.

[0033] Regarding the viscosity of the resin when applied to the woven fabric, when A is the viscosity measured in an environment at 20°C and B is the viscosity measured in an environment at 30°C, the value obtained by dividing A by B is preferably 1.05 or more and 1.30 or less, and more preferably 1.10 to 1.20. If the value obtained by dividing A by B is 1.30 or less, excessive viscosity reduction does not occur when the temperature is raised for curing the resin, so strike-through is less likely to occur in the resin coating process, and the air leakage amount during a high-pressure air permeability test is sufficiently reduced. Furthermore, sufficient flexibility as an airbag base fabric can be obtained, and the base fabric is less likely to burst even under instantaneous high pressure. On the other hand, if the value obtained by dividing A by B is 1.05 or more, the resin can be cured in a state where it has sufficiently penetrated into the gaps between fibers.

[0034] The temperature of the resin when applied to the fabric is preferably between 28°C and 30°C. If the temperature of the resin when applied to the fabric is 28°C or higher, the resin can sufficiently penetrate into the voids between the fibers. On the other hand, if the temperature of the resin when applied to the fabric is 30°C or lower, the resin is less likely to seep through to the back of the fabric during coating, the amount of leakage during high-pressure ventilation tests is sufficiently small, and the curing reaction does not start unexpectedly, and the resin can sufficiently penetrate into the voids between the fibers. The temperature of the resin was measured by attaching a sheathed thermocouple opposite to the joint 15 cm away from the outlet of the resin supply pipe and measuring the fluid temperature inside the pipe.

[0035] When applying the resin to the fabric, the temperature of the fabric is preferably 25°C to 28°C. If the temperature of the fabric is 25°C or higher when the resin is applied, the resin temperature will decrease gradually after application to the fabric, allowing the resin to penetrate sufficiently into the voids between the fibers. If the temperature of the fabric is 28°C or lower when the resin is applied, the resin is less likely to seep through to the back during application, the amount of leakage during high-pressure ventilation tests will be sufficiently small, and the curing reaction will not start unexpectedly, allowing the resin to penetrate well into the voids between the fibers. Normally, in the process of applying resin to a fabric, the temperature is controlled to be relatively low because high room temperature may promote crosslinking. However, in the manufacturing of the airbag base fabric of this embodiment, it is preferable to deliberately control the room temperature to be high, which makes it possible to control the penetration behavior of the resin. Furthermore, to determine the temperature of the fabric, the surface temperature was measured using a non-contact thermometer (HIOKI FT3700) at three points: 10 cm away from the resin coating blade in the warp direction of the fabric, 10 cm from each of the selvage edges of the fabric, and in the center of the fabric. The average value of the three points was used.

[0036] When the resin is applied to the fabric, the coating tension of the fabric is preferably 7 N / cm or more and 20 N / cm or less, more preferably 10 N / cm or more and 15 N / cm or less, and even more preferably 13 N / cm or more and 15 N / cm or less. In a fabric base cloth coated with resin at a coating tension of 7 N / cm or more, the fibers constituting the fabric base cloth are coated in a state in which the filaments constituting the yarn are sufficiently aligned with each other. This makes it difficult for the resin to penetrate into the inside of the yarn, but easy for it to penetrate to the outside of the yarn, making it easier to achieve the desired penetration state.

[0037] The amount of resin applied is 5 g / m² per unit area of ​​the fabric. ２ 30g / m or more ２ The following is preferable, and more preferably, 8 to 25 g / m² ２ More preferably, 10 to 23 g / m ２ When the amount of resin applied is within the above range, the fabric tends to have a good balance of improved mechanical properties (tear strength, slip resistance, etc.) as well as good storage properties. ２ If the above conditions are met, the resin will be uniformly applied to the surface of the base fabric, and sufficient airtightness will be achieved. Therefore, the resulting airbag will be able to maintain its internal pressure during deployment. On the other hand, the amount of resin applied is 30 g / m². ２ If the following conditions are met, the resulting base fabric will be less expensive, lighter, and more compact.

[0038] The drying process after applying the resin to the fabric is preferably carried out at a temperature of 160°C to 190°C. More preferably, the temperature of the lower surface of the base fabric is higher than the temperature of the upper surface. This makes it easier for the resin to penetrate to the outside of the yarn while making it difficult for it to penetrate to the inside of the yarn, thus making it easier to achieve the desired penetration state. In order to create a temperature difference between the upper and lower surfaces of the base fabric during the drying process, for example, the output ratio of the tenter's circulation fan can be set to, for example, 100% on the upper side and 40% on the lower side.

[0039] In this embodiment, the resin penetration of the woven fabric base for the airbag is preferably sufficient to penetrate the outside of the yarn, but less to the gaps between the filaments inside the yarn. Sufficient resin penetration to the outside of the yarn causes the yarns constituting the woven fabric base to become a single unit, and furthermore, the yarns are bonded to each other with the resin, providing a stress distribution effect when external stress is applied. In addition, the small amount of resin penetration into the gaps between the filaments inside the yarn results in a flexible woven fabric base, which causes adjacent yarns to stick together when external stress is applied, providing a stress distribution effect.

[0040] In the cross-section of the woven fabric base for airbags in this embodiment, it is preferable that the thickness of the silicone layer on the coated side is relatively small at the intersections. In general, the cross-section of resin-coated woven fabric bases for airbags usually has a relatively large thickness of the silicone layer at the intersections, but in the woven fabric base of this embodiment, by coating in a way that reduces the thickness of the intersections, sufficient penetration to the outside of the yarn can be achieved even with a small amount of coating. Furthermore, by reducing the difference between the thickness of the intersections and the thickness of the floating center, the stress distribution is leveled when external stress is applied, and the effect of stress distribution can be obtained. The ratio of the thickness of the intersections to the thickness of the floating part is

[0041] In this embodiment, the silicone penetration rate of the yarn contact area of ​​the woven fabric base for the airbag is preferably 30% to 99%, more preferably 40% to 90%, and even more preferably 50% to 85%. If the silicone penetration to the yarn contact area is 30% or more, the warp and weft threads can be sufficiently in close contact, and if it is 99% or less, the warp and weft threads will not be excessively in close contact, and sufficient slippage can be obtained. When external stress is applied, the warp and weft threads can slip appropriately, allowing for stress distribution accompanied by plastic deformation.

[0042] Returning to the description of the entire woven fabric base fabric, the cover factor (CF) of the woven fabric constituting the airbag woven fabric base fabric resin-coated on at least one side in the present embodiment is preferably 1800 or more, more preferably 1900 or more. Further, the cover factor (CF) of the woven fabric is preferably 2500 or less, more preferably 2400 or less. When the cover factor of the woven fabric is within the above range, the resulting base fabric is likely to achieve both compactness and air barrier properties. When the cover factor of the woven fabric is less than 1800, the structural binding force of the woven fabric becomes weak, and the resulting base fabric tends to have low slip resistance. On the other hand, when the cover factor of the woven fabric exceeds 2300, compactness tends to decrease. The cover factor (CF) is represented by the following formula.   CF = √(d) × (2 × W) {In the formula, d is the average total fineness (dtex) of warp and weft of the constituent yarns, and W is the average warp and weft weaving density (yarns / 2.54 cm).}

[0043] The warp-weft density ratio of the airbag woven fabric base fabric resin-coated on at least one side in the present embodiment is preferably 0.95 or more and 1.05 or less, more preferably 0.97 to 1.03, still more preferably 0.98 to 1.02. When the warp-weft density ratio is 0.95 to 1.05, the density difference between warp and weft is sufficiently small, so that the load applied to the base fabric during airbag deployment can be uniformly received, and even in the base fabric portion where stress is concentrated, the load can be uniformly dispersed and the base fabric is less likely to break.

[0044] The basis weight of the airbag woven fabric base fabric resin-coated on at least one side in the present embodiment is 100 g / m ２ or more and 300 g / m ２ or less is preferable, 120 g / m ２ to 220 g / m ２ is more preferable, 140 g / m ２ to 210 g / m ２ is still more preferable, 150 g / m ２ to 190 g / m ２ is even more preferable. When the basis weight of the base fabric is 100 g / m ２ or more, insufficient mechanical strength and heat resistance of the base fabric are less likely to occur; on the other hand, when the basis weight is 300 g / m ２ or less, the airbag does not become excessively heavy.

[0045] The thickness of the woven fabric base for the airbag, which has at least one side coated with resin in this embodiment, is preferably 0.15 mm to 0.35 mm, more preferably 0.18 mm to 0.30 mm, and even more preferably 0.19 mm to 0.28 mm. By setting the thickness of the base fabric within the above range, it is possible to achieve both the mechanical strength and heat resistance of the base fabric and the ability to house the airbag. When the thickness of the base fabric is within the above range, it is easier to secure passenger space in a vehicle equipped with an airbag. In addition, the vehicle can be designed with greater freedom in terms of interior design.

[0046] In this embodiment, the elongation of the woven fabric base for the airbag, which has at least one side coated with resin, is preferably 20% to 40% in both the warp and weft directions, and more preferably 25% to 35%. The elongation of the airbag base fabric differs in the warp, weft, and diagonal directions. Therefore, if the elongation at break of the airbag base fabric is 20% or more, stress is less likely to concentrate in areas with less elongation when the airbag is deployed, allowing the predetermined internal pressure to be maintained and reducing the likelihood of rupture from areas of stress-concentrated base fabric. While a relatively high elongation of the base fabric is preferable, if it is 40% or less, mesh opening during airbag inflation is suppressed, making it easier to maintain the predetermined internal pressure.

[0047] In this embodiment, the slip resistance of the woven fabric base for the airbag, which has at least one side coated with resin, is preferably 300 N to 1500 N in both the warp and weft directions, more preferably 400 N to 1000 N, and even more preferably 400 N to 800 N. If the slip resistance of the base fabric is 400 N or more, the fibers constituting the base fabric restrain each other's movement, reducing the opening of the base fabric when a load is applied to the sewing threads during airbag inflation, and suppressing gas leakage from the sewing area under high pressure, resulting in an airbag with good energy efficiency during airbag inflation. On the other hand, if the slip resistance of the base fabric is 1500 N or less, the fibers constituting the base fabric do not restrain each other excessively, and have the freedom to move while maintaining the warp and weft base fabric structure, so the base fabric becomes more flexible and the airbag storage capacity is improved.

[0048] The tear strength of the woven fabric base for the airbag, in this embodiment, which has at least one side coated with resin, is preferably 180 N or more in both the warp and weft directions, more preferably 200 N or more, and even more preferably 250 N or more. If the tear strength of the base fabric is 180 N or more, when the inside of the cushion becomes high pressure when the airbag inflates, bursting due to tearing is less likely to occur. In addition, even if the cushion is damaged by abrasion from the airbag device cover or interior parts of the vehicle body, or if the cushion is damaged by cuts from glass fragments, or if pinholes occur in the airbag base fabric due to inflator residue, etc., tears originating from these points are less likely to spread, and it is possible to prevent an extreme drop in pressure inside the cushion. There is no particular upper limit to the tear strength; for example, it may be 800 N or less.

[0049] The rigidity of the woven fabric base for the airbag in this embodiment, which has at least one side coated with resin, is preferably 60 mm to 150 mm, more preferably 70 to 130 mm, and even more preferably 80 to 120 mm. A rigidity of 150 mm or less of the base fabric results in a flexible base fabric, which distributes stress while undergoing plastic deformation when stress is applied to the base fabric, making it less likely to break.

[0050] The dynamic air permeability value of the airbag fabric base material for this embodiment, in which at least one side is resin-coated, is 0.040 L / dm². ２ Preferably less than or equal to / min, and 0.030 L / dm ２ / min or less is more preferable, and 0.010 L / dm ２ A value of 0.040 L / dm² is even more preferable. ２ By keeping the value below / min, gas leakage during airbag inflation and deployment can be suppressed, improving the energy efficiency of airbag inflation.

[0051] Another embodiment of the present invention is an airbag made by sewing the above-mentioned woven fabric base for airbags, wherein the average value of the tensile strength utilization rate N2(-), which is the value obtained by dividing the notch tensile strength N1(N) of the woven fabric base by the tensile strength (N), in the warp and weft directions is 0.50 or more and 0.95 or less, such as a side curtain airbag, a pedestrian airbag, or a far side airbag.

[0052] The woven fabric base for airbags, of which at least one side is resin-coated, can be sewn together and used as an airbag. By using the woven fabric base for airbags in the inflation chamber of the airbag, it is possible to create an airbag cushion that is flexible, lightweight, easy to store, and less prone to tearing at the seams, even in airbags with highly asymmetrical shapes. When the woven fabric base for airbags is used in the inflation chamber of the airbag, a covering material may be placed inside the airbag body (the side that is filled with gas) or outside the airbag body. Placing the covering material inside the airbag body protects the fabric from high-temperature gas generated from the inflator. Placing the covering material outside the airbag body protects the base fabric from abrasion when it comes into contact with the interior materials of the vehicle body, etc., when the airbag is deployed.

[0053] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0054] (1) Total fineness (dtex) of the constituent yarns The apparent fineness of the yarns extracted from the airbag base fabric after the coated resin was dissolved using a chemical was measured in accordance with Annex H of JIS L 1096:2010, and the average value of the warp and weft directions was taken as the total fineness (dtex) of the constituent yarns.

[0055] (2) Number of single filaments The cross-section of the airbag base fabric was observed using a scanning electron microscope (KEYENCE VE-9800), and the number of filaments of 10 woven threads was counted. The number of filaments with the highest frequency among the 10 threads was defined as the number of single filaments.

[0056] (3) Single filament fineness (dtex) The single filament fineness (dtex) was obtained by dividing the total fineness of the constituent yarns by the number of filaments.

[0057] (4) Specific gravity (g / cm ３ The values ​​listed in the Fiber Performance Table on page 242 of the Fiber Handbook 2023 (edited by the Japan Chemical Fibers Association) were used as specific gravity. Nylon 66 fiber was 1.14, and polyester fiber was 1.38 (g / cm³). ３ )

[0058] (5) Resin viscosity (Pa·s) was measured using a rheometer in accordance with ISO 3219. For resins of the type that are mixed and applied together, such as a main agent and a hardener, the viscosity of the two agents was measured using a variable rotation and rotation mixer, stirring at 1000 rpm for 1 minute twice, followed by stirring at 2000 rpm for 1 minute under vacuum. Then, the resin viscosity measured at 20°C was taken as A, and the resin viscosity measured at 30°C was taken as B, and the value A / B was calculated by dividing A by B.

[0059] (6) Temperature of the coating resin (liquid temperature, (°C)) The temperature of the coating resin was measured by attaching a sheathed thermocouple opposite to the joint 15 cm away from the outlet of the coating resin liquid supply pipe, and measuring the fluid temperature inside the pipe.

[0060] (7) Temperature of the fabric during resin coating (°C) The temperature of the fabric was measured using a non-contact thermometer (HIOKI FT3700) at three points: 10 cm away from the resin coating blade in the warp direction of the fabric, 10 cm from each of the selvage edges of the fabric, and in the center of the fabric. The average of the three points was taken as the temperature of the fabric.

[0061] (8) Weave density was measured according to JIS L1096:2010 8.6.1b) Method B, as per Annex FA.

[0062] (9) The warp-to-weft density ratio was calculated by dividing the weave density in the warp direction by the weft direction.

[0063] (10) Cover Factor (CF) The cover factor (CF) of the fabric constituting the base fabric for the airbag was calculated using the following formula: CF = √(d) × (2 × W) {wherein d is the average total fineness (dtex) of the constituent yarns in the warp and weft, and W is the average weave density (threads / 2.54 cm).}

[0064] (11) Basis weight (g / m ２ ) Base fabric for airbags (including covering material, "base fabric weight"), and base fabric (woven fabric), and covering material (resin coating, "coating amount"), weight (g / m²) ２The amount of resin applied was determined from the mass per unit area measured in accordance with JIS L 1096:2010, 8.3.2. For the amount of resin applied, a blank sample was prepared by processing a base fabric under the same conditions except that no resin was applied. The basis weight of the blank sample was measured, and the difference between the basis weight of the resin-coated base fabric and the basis weight of the blank sample was calculated as the amount of resin applied. If a blank sample could not be prepared and the amount of resin applied could only be calculated from the resin-coated base fabric, the amount of resin applied may be calculated by dissolving the woven base fabric with a chemical agent, subtracting the weight of the base fabric after dissolution from the weight of the original coated base fabric, and then dividing that value by the area of ​​the resin-coated base fabric. The chemical agent used to dissolve the woven base fabric was a solvent for measuring the solution viscosity of synthetic fibers. In the case of a base fabric made of polyamide fibers, a sample of an area of ​​0.3 m square (A) was taken, degreased with dichloromethane, and dried at 105°C. This is dissolved in 200 g of 90% formic acid at room temperature, the insoluble matter is filtered out using a glass sintered filter (VIDTEC glass filter 17G-3, manufactured by Cosmo Speed ​​Co., Ltd.), the sample is thoroughly washed with formic acid and water, the insoluble matter is dried at 105°C, and its mass is accurately weighed (M). The coating weight (g / m2) is obtained by dividing the insoluble matter in formic acid (M) by the area of ​​the fabric sample (A). In the case of a base fabric made of polyethylene terephthalate fibers, the calculation is the same except that it is dissolved in phenol / 1,2-dichlorobenzene (50 / 50).

[0065] (12) Thickness of the base fabric (mm) Five 100 mm x 100 mm samples (base fabric) were taken, and the thickness (mm) of the airbag base fabric was measured according to the thickness method B described in JIS L 1096:2010. The applied pressure was 1 kPa, and a presser foot with a diameter of 10.5 mm was used. The thickness of each sample was measured, and the average value was calculated.

[0066] (13) Tensile strength (N / cm) According to Method A described in JIS L 1096:2010, the tensile strength (N) of the airbag base fabric was measured and the value obtained by dividing it by the width (cm) of the test piece was defined as the tensile strength (N / cm).

[0067] (14) Elongation (%) The elongation rate at the time of rupture of the airbag base fabric was measured according to Method A described in JIS L 1096:2010 and expressed as elongation (%).

[0068] (15) Slip resistance (N) In accordance with ASTM D6479, the slip resistance was measured five times in both the longitude and latitude directions, and the average value was taken as the slip resistance (N).

[0069] (16) Stiffness (mm) In accordance with ASTM D-5732 (cantilever method), the stiffness was measured five times each in the warp and weft directions with the coated side facing up, and then similarly five times in the warp and weft directions with the coated side facing down. The average value was taken as the stiffness. The sample side was 150 mm in length and 20 mm in width, and the stiffness (mm) of the airbag base fabric was measured.

[0070] (17) Dynamic airflow rate (L / dm ２ (min) A 20cm square sample was set in an airbag-specific breathability tester (air permeability meter) FX3350 (manufactured by Textest GmbH, Switzerland). One side of the base fabric was pressurized, and the differential pressure between the two sides of the base fabric was adjusted to 100 ± 5 kPa. The airflow rate passing through at that time was measured. In addition, measurements were taken at five random locations within the same sample, and the average value was calculated.

[0071] (18) Sewing Strength (N) The sewing strength of the airbag base fabric was measured according to the JIS L1093:2011 seam strength test (Method A-1: ​​horizontal seam method (see Figure 1 (A))) and defined as sewing strength (N). Test specimens were taken with dimensions of 200 mm in the direction parallel to the seam and 100 mm in the direction perpendicular to the seam. Two pieces of base fabric were placed on top of each other with the coated side facing inward. Gunze airbag sewing thread (total fineness 1400 dtex, nylon 66 multifilament fiber 700 dtex 2-ply) was used for both the upper and lower threads, and the sewing strength was measured per 10 cm. The fabric was sewn together using a straight stitch with 50 stitches per inch. The grips were positioned opposite each other: a small grip measuring 25 mm parallel to the tension direction and 25 mm perpendicular to the tension direction, and a large grip measuring 25 mm parallel to the tension direction and 50 mm perpendicular to the tension direction. The base fabric was then secured. The grips were spaced 76 mm apart, and the seam was positioned in the center between the grips. The fabric was pulled at a tensile speed of 300 mm / min, and the maximum tensile strength until the seam broke was measured. Five measurements were taken in both the warp and weft directions, and the average value was defined as the sewing strength.

[0072] (19) Notch tensile strength N1 (N) As shown in Figure 1, a sample side measuring 300 mm in length and 50 mm in width was cut out, and notches (cuts) were made from both sides so that the apex was at a length of 150 mm. The notches were cut to form a right triangle with a length of 20 mm and a width of 10 mm. Using this sample, the notch tensile strength (N) of the airbag base fabric was measured five times in both the warp and weft directions according to Method A described in JIS L 1096:2010, and the average value of the warp and weft directions was taken as the notch tensile strength N1.

[0073] (20) Tensile Strength Utilization Rate N2 The tensile strength utilization rate N2 was defined as the value obtained by dividing the notch tensile strength N1 (N) of the woven base fabric by the tensile strength (N). When measuring the notch tensile strength, the effective width was 30 mm, so the tensile strength (N) used was three times the tensile strength (N / cm).

[0074] (21) Permeability at yarn contact area A 1 cm x 3 cm square sample was taken from the woven fabric base for the airbag, and the observation sample was cut out by placing a razor blade perpendicular to the warp or weft threads so that the measurement surface was a cross-section in the thickness direction of the base fabric. The cutting position was such that it passed through the center of the floating area, and if necessary, the cut surface was embedded in resin to maintain its shape and then polished. The cross-section of the sample was observed using an electron microscope capable of elemental mapping (see Figure 6). When the yarn width in the cross-section of the base fabric, i.e., the length between the filaments at both ends of the yarn, was P2, and the length of the area where no silicone penetration was observed was P1, the permeability at yarn contact area was calculated by P1 / P2 × 100 (see Figure 7). Cross-sectional observations were performed at least 10 locations, and the average value of 10 measurements was used.

[0075] (22) Ratio of coating thickness between intersecting and floating areas Similar to (21) above, a cross section of the base fabric was cut out and observed. The thickness of the coating layer at the position circumscribing the filament at the end of the yarn in the cross section of the base fabric was defined as Ta1 and Ta2, and the average value of these was defined as the intersecting area thickness Ta (see Figure 8). In addition, the length P2 between the filaments at both ends of the yarn was divided into 21 equal parts, and the thickness of the silicone layer was measured at 20 locations, and the average value of these measurements was defined as the floating area thickness Tb. The value of Tb / Ta was defined as the ratio of the coating thickness between the intersecting area and the floating area. Cross section observations were performed at least 10 locations, and the average value of 10 measurements was used.

[0076] (21) Elliptical Burst Pressure (kPa) Two resin-coated woven fabrics were cut into the shape shown in Figure 2 and stacked with the coated side facing inward. The outer edge was sewn with a single row of lockstitch (50 stitches / 10cm pitch) using sewing thread (Gunze nylon 66, 1400dtex) with a seam allowance of 10mm. Using the same sewing conditions, a circular shape with a diameter of 45mm was sewn in the center to obtain an evaluation airbag. The fabricated evaluation airbag was connected to a burst test apparatus as shown in Figure 3, and a pressure port (Kyowa Electric Industry Co., Ltd.) was attached to the airbag so that the pressure inside the airbag could be measured. Nitrogen gas was filled into a tank (capacity 30.05L) in the apparatus until it reached 1.0 MPa, and the gas was instantaneously released into the airbag by opening the solenoid valve. A graph of the time change of the internal pressure until the airbag ruptured was obtained. The maximum pressure shown in the graph was recorded as the pressure at the time of burst (burst pressure).

[0077] (22) Burst pressure of complex shape (kPa) A resin-coated woven fabric base was cut from the outer circumference of the shape shown in Figure 4(A) with a seam allowance of 10 mm, referring to Japanese Patent Application Publication No. 2024-037143, and sewn together with a single row of lockstitch (50 stitches / 10 cm pitch) using sewing thread (Gunze nylon 66, 1400 dtex) with the coated side facing inward, to obtain an evaluation airbag as shown in Figure 4(B). A connecting tube pipe was fixed to the opening 40 of the fabricated evaluation airbag so as not to leak air, and connected to a burst test apparatus as shown in Figure 3 as shown in Figure 5. A pressure port (manufactured by Kyowa Denki) was attached to the airbag so that the pressure inside the airbag could be measured. Nitrogen gas was sealed into a tank (capacity 30.05 L) in the apparatus until it reached 1.0 MPa, and the gas was instantaneously released into the airbag by opening the solenoid valve, and a graph of the time change of the internal pressure until the airbag burst was obtained. The maximum pressure shown in the graph was recorded as the pressure at the time of the burst (burst pressure).

[0078] [Example 1] Using nylon 66 yarn with a fineness of 490 dtex and 136 single filaments, a plain weave fabric was woven on a waterjet loom, followed by scouring and drying. When a silicone resin with a viscosity of 51.1 Pa·s measured at 20°C and a viscosity of 42.9 Pa·s measured at 30°C was transferred from the tank to the coating area, the piping was heated with a ribbon heater to bring the resin temperature to 28.5.0°C. This resin was applied to the surface of the base fabric, which had a base fabric temperature of 27.0°C, using a knife, with a coating amount of 20 g / m². ２ A silicone-coated base fabric was prepared. The properties of the obtained base fabric are shown in Table 1 below.

[0079] [Example 2] When supplying the silicone resin from the tank to the coating area, the piping was heated with a ribbon heater to bring the resin temperature to 29.0°C. The resin was then applied to the surface of the base fabric, which had a base fabric temperature of 26.0°C, using a knife, with a coating amount of 12 g / m². ２ Except for the above, the base fabric was prepared in the same manner as in Example 1. The properties of the obtained base fabric are shown in Table 1 below.

[0080] [Example 3] Using a polyester yarn with a fineness of 550 dtex and 140 single strands, the coating amount was 20 g / m ２ Except for the above, the base fabric was prepared in the same manner as in Example 1. The properties of the obtained base fabric are shown in Table 1 below.

[0081] [Example 4] Using nylon 66 yarn with a fineness of 700 dtex and 105 single strands, the coating amount was 20 g / m ２ Except for the above, the base fabric was prepared in the same manner as in Example 1. The properties of the obtained base fabric are shown in Table 1 below.

[0082] [Example 5] A base fabric was prepared in the same manner as in Example 1, except that a silicone resin with a viscosity of 40.2 Pa·s measured at 20°C and a viscosity of 39.5 Pa·s measured at 30°C was used. The properties of the obtained base fabric are shown in Table 1 below.

[0083] [Example 6] A base fabric was prepared in the same manner as in Example 1, except that a silicone resin with a viscosity of 57.7 Pa·s measured at 20°C and a viscosity of 41.3 Pa·s measured at 30°C was used. The properties of the obtained base fabric are shown in Table 1 below.

[0084] [Example 7] A base fabric was prepared in the same manner as in Example 1, except that the resin temperature during silicone resin coating was 27.0°C. The properties of the obtained base fabric are shown in Table 1 below.

[0085] [Example 8] A base fabric was prepared in the same manner as in Example 1, except that the temperature of the fabric during silicone resin coating was 30.0°C. The properties of the obtained base fabric are shown in Table 1 below.

[0086] [Example 9] A base fabric was prepared in the same manner as in Example 1, except that the weaving tension was 50 cN / dtex and the coating tension was 9 N / cm. The properties of the obtained base fabric are shown in Table 1 below.

[0087] [Example 10] A base fabric was prepared in the same manner as in Example 1, except that the washing temperatures were 60°C for the first tank, 70°C for the second tank, and 80°C for the third tank. The properties of the obtained base fabric are shown in Table 1 below.

[0088] [Example 11] The base fabric was prepared in the same manner as in Example 1, except that the output of the tenter fan was set to 100% for both the upper and lower sections. The properties of the obtained base fabric are shown in Table 1 below.

[0089] [Example 12] A base fabric was prepared in the same manner as in Example 1, except that an aramid yarn with a fineness of 490 dtex and 136 single filaments was used. The properties of the obtained base fabric are shown in Table 1 below.

[0090] [Comparative Example 1] Referring to Example 1 of Japanese Patent Publication No. 2008-50716, a plain weave fabric was obtained using 470 dtex, 72-filament nylon 66 yarn with a weave density of 46 threads / 2.54 cm for both warp and weft. Next, a solvent-free silicone resin with a viscosity of 15,000 mPa·s was applied by pressing it with a clamping force of 2.5 N / cm using a stainless steel knife with a blade thickness of 0.1 mm at the contact point and a urethane bed. After that, it was heat-treated using a pin tenter dryer at 180°C for 60 seconds, and the resin coating amount was 12 g / m². ２A base fabric for airbags was obtained. Since there was no specific description of other processes, in this Comparative Example 1, conditions commonly used in the art were adopted in order to reproduce Example 1 in a manner that is normally performed by those skilled in the art. The properties of the obtained base fabric are shown in Table 1 below. The obtained base fabric had a very low burst pressure for complex shapes.

[0091] [Comparative Example 2] A base fabric was prepared in the same manner as in Example 1, except that the weaving tension was 50 cN / dtex, the washing temperature was 60°C / 70°C / 80°C, the coating tension was 9 N / cm, the resin viscosity A / B was 1.4, the resin and base fabric temperature was 20°C, and the tenter setting was 100% for both upper and lower layers. The properties of the obtained base fabric are shown in Table 1 below. The obtained base fabric had a very low burst pressure for complex shapes.

[0092]

[0093] If an airbag (cushion) is made using the woven fabric for airbags with at least one side coated with resin according to the present invention, the resulting airbag (cushion) will be flexible, lightweight, easy to store, energy efficient in airbag inflation, and less prone to seam tearing even under high pressure. Therefore, the woven fabric for airbags with at least one side coated with resin according to the present invention is an airbag base fabric particularly suitable for applications such as pedestrian airbags and far-side airbags where storage is required.

[0094] 20 Burst test device 21 Nitrogen cylinder 22 Pressure valve 23 Pressure tank 24 Solenoid valve 25 Fixing band 26 Gas outlet 27 Circular stitching 28 Airbag cushion 29 PC 30 Data logger 31 Pressure detection unit 32 Air tube 33 Pressure port mounting unit 34 Outer circumference stitching 40 Opening 41 Tube piping

Claims

1. A woven fabric for airbags, wherein at least one side is coated with resin, and when a tensile test is performed by grasping both ends of a test piece with a notch made in the center of the woven fabric, the average value of the notch tensile strength N1 (N) in the warp and weft directions obtained is 1100 or more and 3000 or less.

2. The woven base fabric for airbags according to claim 1, wherein the average value of the tensile strength utilization rate N2(-), which is the value obtained by dividing the notch tensile strength N1(N) by the tensile strength (N), in the warp and weft directions is 0.50 or more and 0.95 or less.

3. The amount of resin coating applied to the woven base fabric is 5 g / m². ２ 30g / m or more ２ The following is the fabric base for an airbag according to claim 1 or 2.

4. The woven fabric base for an airbag according to claim 1 or 2, wherein the stiffness and flexibility of the woven fabric base in both the warp and weft directions are 60 mm or more and 100 mm or less.

5. The woven fabric base for airbags according to claim 1 or 2, wherein the warp-to-weft density ratio of the woven fabric base is 0.95 or more and 1.05 or less.

6. The woven fabric base for an airbag according to claim 1 or 2, wherein the slip resistance in the warp and weft directions of the woven fabric base is 300 N or more and 1500 N or less.

7. The woven fabric base for airbags according to claim 1 or 2, wherein the strength of the woven fabric base in both the warp and weft directions is 350 N / cm or more and 1000 N / cm or less.

8. The woven fabric base for airbags according to claim 1 or 2, wherein the elongation in the warp and weft directions of the woven fabric base is 20% or more and 40% or less.

9. The woven fabric base for an airbag according to claim 1 or 2, wherein the fibers constituting the woven fabric base are made of nylon 66 or polyethylene terephthalate.

10. The woven fabric base for airbags according to claim 1 or 2, wherein the viscosity of the resin coating agent applied to the woven fabric when applied to the fabric is such that, when A is the viscosity measured at 20°C and B is the viscosity measured at 30°C, the value obtained by dividing A by B is 1.05 or more and 1.30 or less.

11. The woven fabric for airbag according to claim 1 or 2, wherein the cross-section of the single fibers constituting the woven fabric base is circular.

12. An airbag formed by sewing together the woven fabric base for airbags described in claim 1 or 2.

13. The airbag according to claim 12, having a tether.

14. The side curtain airbag according to claim 12.

15. The pedestrian airbag according to claim 12.

16. The far-side airbag according to claim 12.

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