JP2004204404A - Ground fabric for airbag, airbag, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag for protecting the occupants in the crush of an automobile, having mechanical properties, air-barrierness and compact housing space as an airbag, and producible with little loss of the cloth in cutting to improve the cost performance. <P>SOLUTION: The ground fabric for an airbag has a thermoplastic layer laminated on at least one surface of a woven fabric made of a synthetic fiber. The thickness T1 of the center part of the fabric and the thickness T2 of the coating edge part satisfy the relationship 0.9≤T1/T2, and the width W of the fabric and the width C of the resin-coated part of the fabric satisfy the relationship 0.95≤C/W≤0.99. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００４２】
【発明の効果】本発明によれば、エアバッグとしての機械的特性、空気遮断性、収納コンパクト性を兼ね備え、かつ、裁断時のロスが少なく、コストパフォーマンスに優れたエアバッグ用基布を提供するものことができ、エアバッグ乗員保護システムを普及推進させることができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an airbag base fabric in which a resin is laminated, and more particularly, to improve the thickness difference of a base fabric in which a resin is laminated on a woven fabric, and to reduce the thickness of the ear end portion of the woven fabric by using ear fins. The present invention relates to a base fabric for an airbag, an airbag, and a method for manufacturing the airbag, which has a reduced coating width and is excellent in economy.
[0002]
[Prior art]
Conventionally, for the purpose of imparting functions such as heat resistance, flame retardancy, and air blocking properties to an airbag, chloroprene is added to a woven fabric made of a filament yarn such as nylon 66, nylon 6, or polyester of 100 to 900 dtex. It is common practice to apply a synthetic resin such as silicone or urethane. In general, a knife coater or a comma coater is used for applying such a synthetic resin. The knife coater or the comma coater is used to maintain the function of the above-mentioned airbag, and to coat the resin less uniformly for the purpose of compactness and cost reduction. Is required. However, at present, a high-density woven fabric having a cover factor in the range of 1,400 to 2,300, such as an airbag base cloth, has a problem of ear pallet occurring at the time of weaving. Wrinkles occur at the edges of the woven fabric due to the ears of the parts, so that the resin cannot be applied, and the width of the woven fabric that can be actually used as an airbag is about 90% of the woven width, resulting in loss of the woven fabric.
[0003]
Therefore, in recent years, in order to solve such a problem, the weaving density of the ear end is made higher than that of the other main body base cloth, and the ear lashing which is characterized by the fact that the additional yarn is driven into the ear end is improved. Although a method of performing the above is disclosed (for example, see Patent Documents 1 and 2), it is not sufficient. Further, a method has been disclosed in which two yarns thinner than a ground yarn different from a reno texture are entangled in the ear portion and two ground yarns are alternately inserted as a unit of a yarn to improve ear cling (for example, Patent Document 3). ), The number of processes increases and the cost increases, which is not sufficient. Economic demands such as cost reduction are also increasing for airbags as safety parts, and there is a strong demand for economical airbags with little production loss.
[0004]
[Patent Document 1]
JP-A-9-302549
[Patent Document 2]
JP-A-9-302550
[Patent Document 3]
JP, 2002-212856, A
[Problems to be solved by the invention]
In view of the drawbacks of the conventional airbag, the present invention provides an airbag base having both the mechanical characteristics as an airbag, the air-blocking property, and the compactness of storage, and the loss at the time of cutting is small and excellent in cost performance. Provide cloth.
[0008]
[Means for Solving the Problems]
The present invention employs the following means in order to solve such a problem. That is,
(1) A base fabric for an airbag in which a thermoplastic resin is laminated on at least one surface of a woven fabric made of synthetic fibers, wherein a relationship between a thickness T1 of a central portion of the base fabric and a thickness T2 of a coated end portion is as follows. 0.9 ≦ T1 / T2, and the relationship between the base cloth width W of the base cloth and the coating width C on which the resin is applied is within the range of 0.95 ≦ C / W ≦ 0.99. A base fabric for an airbag, comprising:
(2) The base for an airbag according to (1), wherein the relationship between the thickness T1 of the central portion of the base fabric and the thickness T2 of the coated end portion is 0.95 ≦ T1 / T2. cloth.
(3) The airbag according to any one of (1) and (2), wherein the air permeability measured by a method specified in JIS L1096 A method is 0.01 cc / cm ² / sec or less. Base cloth.
(4) The base fabric for an airbag according to any one of (1) to (3), wherein the thermoplastic resin has an adhesion amount of 5 to 30 g / m ² .
(5) An airbag comprising the base fabric for an airbag according to any one of (1) to (4). (6) A thermoplastic resin is applied to a woven fabric made of synthetic fiber using a knife coater to connect the knife to the woven fabric. A method for producing a base fabric for an airbag, wherein the coating is performed at a pressure within a range of 1 to 15 N / cm and a base fabric tension within a range of 500 to 3,000 N / m.
(7) The method for producing a base fabric for an airbag according to (6), wherein the resin is applied without performing a scouring process on the woven fabric.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention relates to an airbag base fabric in which a thermoplastic resin is laminated on at least one surface of a woven fabric made of synthetic fibers, wherein the relationship between the thickness T1 of the central portion of the base fabric and the thickness T2 of the coated end portion is defined. , 0.9 ≦ T1 / T2, and the relationship between the base cloth width W of the base cloth and the coating width C on which the resin is applied is in the range of 0.95 ≦ C / W ≦ 0.99. As a result, the combination of mechanical characteristics as an airbag, air-blocking properties, and compactness of storage is achieved, and the loss at the time of cutting is reduced, resulting in significantly improved cost performance. Things. Here, the coating width refers to a base cloth width which can be effectively used as a coating base cloth for an airbag.
[0010]
Examples of the woven fabric made of the synthetic fibers constituting the present invention include nylon 6.6, nylon 6, nylon 12, nylon 4.6, a copolymer of nylon 6 and nylon 6.6, and nylon 6 with polyalkylene glycol and dicarboxylic acid. Polyamide fibers such as copolymers obtained by copolymerizing acids and amines, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, and isophthalic acid, 5-sodium sulfoisophthalic acid or adipic acid as acid components constituting repeating units of polyester. Polyester fibers such as copolymers obtained by copolymerizing aliphatic dicarboxylic acids, etc., aramid fibers represented by copolymers with paraphenylene terephthalamide and aromatic ethers, rayon fibers, sulfone fibers, ultrahigh molecular weight Polyethylene fiber and top Fabric composed of synthetic fibers from a polymer array fiber having a sea-island structure mainly is used. Among these woven fabrics, woven fabrics composed of polyamide fibers and polyethylene terephthalate fibers are preferable, and nylon 66 fibers and nylon 6 fibers are more preferable in terms of impact resistance.
[0011]
Such fibers may contain various additives used for improving productivity or characteristics in the production or processing steps of the raw yarn. For example, a heat stabilizer, an antioxidant, a light stabilizer, a leveling agent, an antistatic agent, a plasticizer, a thickener, a pigment, a flame retardant and the like can be contained.
[0012]
The fineness of the woven yarn constituting the woven fabric is preferably in the range of 90 to 600 dtex, more preferably in the range of 150 to 470 dtex, from the viewpoint of the balance between mechanical strength, thickness and weight. That is, a thickness of less than 90 dtex is preferable from the viewpoint of thickness and weight, but the mechanical strength is insufficient, and a thickness of more than 600 dtex increases the thickness and weight and is inferior in terms of storage.
[0013]
The single-fiber fineness of the fibers constituting the woven yarn is preferably in the range of 1 to 6.5 dtex, more preferably in the range of 2 to 4.5 dtex, and the storability and the adhesiveness to the resin are preferable. Good from the point. If it is less than 1 dtex, there is a problem that the productivity of the yarn is liable to deteriorate. If it exceeds 6.5 dtex, the fabric becomes thick, and when the base fabric for airbags is folded, the base fabric rebound is strong, and in terms of storability. Inferior.
[0014]
Further, the cross-sectional shape of the single yarn of the woven yarn is not limited to a circle, but may be any shape. For example, a symmetrical type such as a flat, rectangular, diamond-shaped, or cocoon-shaped type, as well as a bilaterally asymmetric type, or a combination thereof may be used. Further, there may be protrusions, irregularities, and hollow fibers. It is particularly preferable to use a flat cross-section yarn having a ratio between the long axis and the short axis of the cross section, that is, an aspect ratio of 1.8 to 6, since the thickness of the base fabric can be reduced and the storage property is improved. In addition, the use of a flat cross-section yarn reduces irregularities on the surface of the woven fabric, and can reduce voids generated between the woven yarns constituting the woven fabric, so that a small amount of resin is sufficient to fill and apply the voids. This is preferable in terms of storability and cost.
[0015]
In addition, the woven yarn is preferably non-twisted in terms of low coating. If twisting occurs, the multifilaments converge, so the unevenness of the fabric surface increases, and more resin is required to fill the unevenness of the fabric surface with the resin, the base fabric weight increases, and the storage capacity increases. Not only does it worsen, but the cost increases because the amount of resin increases.
[0016]
The loom for weaving the fabric constituting the base fabric of the present invention may be appropriately selected from various looms used for weaving industrial fabrics. For example, a shuttle loom, a water jet loom (WJL), an air jet loom ( AJL), rapier looms and the like. Among them, a water jet loom (WJL) is preferably used from the viewpoint of reducing the residual oil agent of the base fabric which may affect the flame retardancy of the airbag and productivity.
[0017]
As the woven fabric constituting the present invention, a flat texture, a twill texture, a satin texture, a deformed texture thereof, and the like can be used, but the fabric is not particularly limited thereto. Among these woven structures, a flat structure is preferably used from the viewpoint of the fabric cost and the isostatic deployability of the airbag. Such a fabric does not necessarily need to have a symmetrical structure, and may have an asymmetrical structure. Examples of the asymmetrical design used here include a flat-textile woven fabric having a different number of warp yarns and weft yarns, a warp yarn and a weft yarn having a different yarn type, and a warp yarn or a weft fabric having one of a ripstop or hollow fabric. It is possible to use one having a different organization, such as the one shown in FIG.
[0018]
Examples of the thermoplastic resin laminated on the fabric constituting the present invention include one of synthetic resins such as polyurethane, polyester, polyamide, acrylic, silicone, fluorine, polyethylene, styrene butadiene, and nitrile butadiene. More than one kind can be used, but it is not particularly limited to these. As the synthetic resin, any of a solvent-based resin, an aqueous resin, and a water-dispersed resin can be used as appropriate. Among them, silicone resins are preferably used from the viewpoint of heat resistance.
[0019]
The adhesion amount of the thermoplastic resin in the present invention is preferably in the range of 5 to 30 g / m ² , and more preferably in the range of 8 to ²⁰ g / m ^2. It is good in terms of properties and storage.
[0020]
In the present invention, the relationship between the thickness T1 of the central portion of the base fabric for an airbag and the thickness T2 of the coated end portion is 0.9 ≦ T1 / T2, and more preferably 0.95 ≦ T1 / T2. If T1 / T2 is smaller than 0.9, the thickness of the bag after cutting and sewing will vary greatly, and as a result, the bag will not expand isotropically when the bag is deployed, and will quickly catch the occupant faster. Is inferior. In addition, since the hot gas at the time of deployment hits the bag unevenly, the bag may be greatly damaged by heat, which is not good.
[0021]
In the base fabric for an airbag of the present invention, the relation between the base fabric width W of the base fabric and the coating width C on which the resin is applied is preferably 0.95 ≦ C / W ≦ 0.99. When it is smaller than 0.95, the loss at the time of cutting the bag is large, and the cost performance is inferior. If it is larger than 0.99, the portion holding both ends of the base fabric in the heat setting after resin coating becomes a resin coated portion, which causes wrinkles and is inferior in quality.
[0022]
The air permeability of the airbag base fabric of the present invention is preferably 0.01 cc / cm ² / sec or less. By adjusting to such air permeability, the design range of airbags in various parts is widened, and the airbag can be preferably used for applications requiring extremely low air permeability, such as inflatable curtains, knee airbags, and smart bags.
[0023]
The thickness of the base fabric for an airbag of the present invention is preferably 0.35 mm or less from the viewpoint of compactness in storage, and the rigidity is preferably 100 mm or less in both the vertical and horizontal directions. It is preferable in terms of properties. Further, it is preferable that the tensile strength of the base fabric for an airbag is 400 N / cm or more, the breaking elongation is 15% or more, and the tear strength is 80 N or more from the viewpoint of mechanical properties as an airbag, that is, from the viewpoint of preventing rupture.
[0024]
In addition, the airbag fabric of the present invention has a flame retardancy of less than 100 mm / min measured based on FMVSS302, assuming thermal damage to the fabric caused by the high temperature gas when the airbag is deployed. Is preferred. It is more preferable that the speed is less than 80 mm / min.
[0025]
The base fabric for an airbag of the present invention can be used for a driver seat airbag, a passenger seat airbag, a rear seat airbag, a side airbag, a curtain airbag, a knee airbag, and the like. It can also be applied to functionally applicable parts such as protective head bags, infant protective mini bags, leg protective bags, seat belt bags, etc., satisfying the required requirements in shape, capacity, etc. What should I do?
[0026]
Further, the airbag fabric of the present invention is characterized in that the fabric made of synthetic fiber is thermoplastically coated with a knife coater so that the contact pressure between the knife and the fabric is within a range of 1 to 15 N / cm, and the fabric tension. Can be produced by coating within the range of 500 to 3,000 N / m. When the coating is performed with a knife coater, the control of the attached amount of the thermoplastic resin and the stability of the attached amount are improved. At the time of coating, the contact pressure between the knife and the woven fabric is performed within a range of 1 to 15 N / cm. If it is smaller than 1 N / cm, the amount of resin is large, the weight of the base fabric is large, and the storage compactness is poor. On the other hand, if it is larger than 15 N / cm, the multifilaments constituting the woven fabric may be cut with a knife to cause breakage of the single yarn, and the quality is not only poor, but also the woven fabric surface cannot be covered with the resin film, and the air permeability is low. Not good in terms of aspect. Further, it is extremely important to apply the base fabric tension within the range of 500 to 3,000 N / m in that the ear-tapping of the woven fabric can be temporarily improved during the application and the application width can be controlled. If the base fabric tension is less than 500 N / m, the ear pallets of the woven fabric are not improved, and the coating width cannot be sufficiently secured. On the other hand, if it is larger than 3,000 N / m, not only a uniform tension may not be applied in the width direction of the woven fabric, but also dimensional stability is inferior due to shrinkage during bag production. The resin viscosity when applying with a knife coater is preferably in the range of 5 to 20 Pa · s. When the viscosity is less than 5 Pa · s, the viscosity is too low, and the resin penetrates into the base fabric, so that not only is the air permeability inferior, but also the amount of coating is large in order to achieve the low air permeability. Not good. On the other hand, if it is larger than 20 Pa · s, the viscosity is too high, so that it is difficult to reduce the amount of resin to be applied (coating thinly and uniformly), which is not good in terms of storability and costly.
[0027]
As the knife coating method, there are a knife over roll method, a knife over belt method, and a floating knife method, but the floating knife method is preferably used because the coating amount can be reduced.
[0028]
In addition, the scouring and setting process before coating is performed to reduce the ears of the base cloth and perform the coating more smoothly. In the present invention, the base cloth tension is as high as 500 to 1,500. Because the resin is applied with tension, it is possible to apply while reducing the earlashes. Therefore, it is preferable to use a greige machine or a woven fabric that is a greige machine set without performing the scouring setting process from the viewpoint of cost reduction.
[0029]
【Example】
Next, the present invention will be described in more detail with reference to examples. Various evaluations in the examples were measured by the following methods.
[0030]
Weight per unit area (resin adhesion amount): Determined according to JIS L1096 (8.4.2 method).
[0031]
Thickness: Measured according to JIS L1096. In addition, the measured value of the central part of the base cloth was obtained by dividing the base cloth into three in the width direction, measuring five points of the thickness of the middle part of the divided base cloth, and calculating the average value thereof. The measured value of the coated end was obtained from the average value of 6 points at both ends at three points at 1 cm intervals from the coated end to the inside of the base cloth.
[0032]
Tensile strength: Based on JIS L1096 (8.12.1A method), the breaking strength at the time of pulling at a woven fabric width of 3 cm, a tension grip interval of 15 cm, and a pulling speed of 200 mm / min was measured.
[0033]
Breaking elongation: Based on JIS L1096 (8.12.1A method), the breaking elongation at the time of pulling at a fabric width of 3 cm, a tension gripping interval of 15 cm, and a pulling speed of 200 mm / min was measured.
[0034]
Tear strength: Based on JIS L1096 (8.15.2A-2 method), the tear strength when pulled at a tensile speed of 200 mm / min was determined.
[0035]
Bending resistance: determined according to JIS L1096 (8.19.1A method).
[0036]
Air permeability: determined according to JIS L1096 (8.27.1A method).
[0037]
Flame retardancy: determined by FMVSS302.
Example 1, Comparative Examples 1 and 2
A nylon 66 fiber having an aspect ratio of a single yarn cross section of 1.0, a total fineness of 470 dtex and 72 filaments, a strength of 8.5 cN / decite, an elongation of 21%, and a water-free yarn. In a jet loom, a plain woven fabric having a warp yarn and a weft yarn density of 55 / 2.54 cm, respectively, was woven and heat set at 190 ° C. for 1 minute. The heat-set fabric was coated with a solvent-free methyl vinyl silicone resin solution having a viscosity of 15 Pa · s by the following method.
(Example 1) Coating was performed by adjusting the contact pressure between the knife and the fabric to 10 N / m and the base fabric tension to 2620 N / m using a floating knife coater using a weir plate knife, and then at 190 ° C. for 2 minutes. A vulcanization treatment was performed to obtain a base fabric for an airbag having a base fabric width of 152 cm.
(Comparative Example 1) The same treatment as in Example 1 was carried out except that the contact pressure between the knife and the fabric was 0.6 N / m, to obtain a base fabric for an airbag having a base fabric width of 152 cm.
(Comparative Example 2) Except that the base fabric tension was set to 300 N / m, the same treatment as in Example 1 was performed to obtain a base fabric for an airbag.
[0038]
Table 1 shows the characteristics of the airbag base fabric thus obtained. The base fabric for an airbag of Example 1 has a base fabric width of 152 cm, a coating width of 148 cm (C / W = 0.97), and a thickness T1 of a central portion of the base fabric and a coating end portion. Although the relationship with the thickness T2 was T1 / T2 = 0.97, the coating width of the airbag base fabric of Comparative Example 1 was 139 cm because the contact pressure was small (C / W = 0.91). , A sufficient coating width could not be secured. In addition, the base fabric for an airbag of Comparative Example 2 had a very small base fabric tension at the time of coating, and was applied without improving the ear flare at the end of the base fabric, so that T1 / T2 = 0. 88, the base cloth width was 152 cm, and the coating width was 142 cm (C / W = 0.93), and a sufficient coating width could not be secured. In addition, the 1.5 cm width at the coating end had to be removed because of the large amount of resin, resulting in an effective use width smaller than the coating width. It can be seen that the airbag according to Example 1 is a base fabric for an airbag which ensures a sufficient coating width and is excellent in economy.
[0039]
Example 2, Comparative Examples 3 and 4
Water jet using a non-twisted yarn, a nylon 66 fiber having an aspect ratio of 3.2 of a single yarn cross section and a total fineness of 350 dtex, a 96 filament strength of 8.0 cN / decite, an elongation of 24%, and no twist. In the room, a plain woven fabric having a warp yarn and a weft yarn with a density of 61 / 2.54 cm, respectively, was woven and heat set at 190 ° C. for 1 minute. The heat-set fabric was coated with a solvent-free methyl vinyl silicone resin solution having a viscosity of 16 Pa · s by the following method.
(Example 2) After coating with a floating knife coater using a weir plate knife so that the contact pressure between the knife and the fabric is 12 N / m and the base fabric tension is 520 N / m, the coating is performed at 190 ° C for 2 hours. Vulcanization treatment was performed for a minute to obtain a base fabric for an airbag.
(Comparative Example 3) The same treatment as in Example 2 was carried out except that the contact pressure between the knife and the fabric was set at 17 N / m, to obtain a base fabric for an airbag.
(Comparative Example 4) Except that the base fabric tension was set to 3200 N / m, the same treatment as in Example 2 was performed to obtain a base fabric for an airbag.
[0040]
Table 1 shows the characteristics of the airbag base fabric thus obtained. The base fabric for an airbag of Example 2 had a base fabric width of 154 cm, a coating width of 148 cm (C / W = 0.96), and a thickness T1 of a central portion of the base fabric and a coating end portion. Although the relationship with the thickness T2 was T1 / T2 = 0.96, the base fabric for an airbag of Comparative Example 3 had a large contact pressure, so that the fabric surface could not be sufficiently covered with the resin film, and Not only can the working width not be secured, but the air permeability and flame retardancy required for an airbag cannot be cleared. In the base fabric for an airbag of Comparative Example 4, since the base fabric tension at the time of coating was very large, uniform tension was not applied in the width direction of the base fabric, and a sufficient coating width could not be secured. It can be seen that Example 2 is a base fabric for an airbag which is more excellent in mechanical properties as an airbag than the comparative example, and which has a sufficient coating width and which is excellent in economy.
[0041]
[Table 1]

[0042]
According to the present invention, there is provided an airbag base fabric which has both mechanical properties as an airbag, air blocking properties, and compactness in storage, has little loss at the time of cutting, and is excellent in cost performance. Can promote the spread of the airbag occupant protection system.

Claims (7)

An airbag base fabric in which a thermoplastic resin is laminated on at least one surface of a woven fabric made of synthetic fibers, wherein a relationship between a thickness T1 of a central portion of the base fabric and a thickness T2 of a coated end portion is 0.9. ≦ T1 / T2, and the relationship between the base cloth width W of the base cloth and the coating width C on which the resin is applied is within a range of 0.95 ≦ C / W ≦ 0.99. Characteristic airbag fabric. 2. The airbag base fabric according to claim 1, wherein a relationship between a thickness T <b> 1 of a central portion of the base fabric and a thickness T <b> 2 of a coated end portion is 0.95 ≦ T1 / T2. 3. And wherein the air permeability measured by the method specified in JIS L1096 A method is less than 0.01cc / cm ² / sec, an airbag fabric of any of claims 1 or 2. Heat adhesion amount of thermoplastic resin is characterized by a 5 to 30 g / m ^2, an airbag fabric according to any one of claims 1 to 3. An airbag comprising the base fabric for an airbag according to claim 1. A thermoplastic resin is applied to a woven fabric made of synthetic fibers by a knife coater so that the knife and the woven fabric have a contact pressure of 1 to 15 N / cm and a base fabric tension of 500 to 3,000 N / m. A method for producing a base fabric for an airbag, wherein the base fabric is applied by a coating method. The method for producing a base fabric for an airbag according to claim 6, wherein the resin is applied without performing scouring of the woven fabric.