JPH04325342A - Sheet for air bag - Google Patents

Abstract

PURPOSE:To provide a sheet for an air bag having improved adhesiveness and excellent bursting strength, air permeability and folding property without inserting an adhesive between a nylon 66 ground fabric and an elastomer. CONSTITUTION:45-250 nylon 66 filaments spun and extended with single yarns 3-6 denier in the normal method are converged, fluid treatment is applied to them, looping and entangling are applied, the filaments are woven at the weaving density 30-60 filaments/inch, and part or the whole of one face of a ground fabric formed with loops on the whole surface is nearly uniformly coated with an elastomer 50-150g/m<2> to form a sheet for an air bag.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a sheet for impact-absorbing airbags to ensure safety, and more specifically, the present invention relates to a sheet made of spun-like nylon 66 treated with fluid treatment.
The present invention relates to an airbag sheet with excellent adhesive properties and long-term storage durability for use in vehicles and the like.

0002

2. Description of the Related Art Seat belts are generally used to protect occupants of various types of transportation vehicles, but even safer airbag systems have been put into practical use. Normally, airbags are made by weaving raw yarn and then layering rubber materials, which are then folded and stored.When the bag receives a shock such as an accident, it instantly inflates with high-pressure gas, ensuring the safety of the occupants. . The important characteristics of an airbag are expected to be impact resistance to withstand instantaneous inflation, high durability during long-term storage, and the ability to be stored compactly.

[0003] Examples of methods for improving storage performance include:
JP-A-64-41438 and JP-A-64-41
It is described in Publication No. 439. On the other hand, as a method for laminating an elastomer on the surface layer of the base fabric, for example, JP-A No. 49
It is described in Japanese Utility Model Publication No. 47692 and Japanese Utility Model Application Publication No. 49-24108. Furthermore, a method to improve adhesion is generally to manually apply rubber glue, etc., but this method causes the organic solvent in the rubber glue to scatter, causing a major environmental problem. .

[0004] The base fabrics for airbags described in JP-A-64-41438 and JP-A-64-41439 improve the flexibility of the base fabric by reducing the single yarn denier, making it easy to fold. It is durable and can be stored compactly. However, in order to increase the adhesion between the base fabric and the elastomer, it is necessary to apply an adhesive such as rubber glue between the base fabric and the elastomer, which causes the base fabric to become hard and remain in the same state for a long time. They have the problem of poor ability to instantaneously expand when stored, and low burst resistance.

On the other hand, in the method of laminating an elastomer on a base fabric described in JP-A-49-47692 and JP-U-49-24108, the laminate and the base fabric used in the airbag are Due to the poor adhesion between the base fabric and the laminate, it has poor foldability when folded and stored in a small size like an airbag, and not only does it require a large storage volume, but it also has poor adhesion when stored. Separation phenomenon between the base fabric and the elastomer was observed in some areas, and the leakage of high-pressure gas injected at the time of a collision could not be prevented, resulting in a problem that the amount of energy absorbed at the time of a collision was small.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in conventional airbag seats. Therefore, an object of the present invention is to provide an airbag sheet that has excellent impact resistance, good adhesion between the base fabric and elastomer, durable storage properties, and the ability to be folded compactly when stored. It is about providing.

[0007] Another object of the present invention is to create a flexible sheet with excellent foldability by directly adhering the base fabric and the elastomer without intervening an adhesive between the base fabric and the elastomer. An object of the present invention is to provide a sheet for an airbag that has excellent peeling resistance and expandability.

[0008]

[Means for Solving the Problems] The above objects are achieved by the following invention. The structure of the present invention is to bundle 45 to 250 single yarns of 3 to 6 deniers made of hexamethylene diamine and adipic acid, and weave looped and intertwined nylon 66 filaments at a weaving density of 30 to 60 filaments/inch. This sheet for an airbag is characterized in that the whole or part of one side of a base fabric having loops formed over the entire surface is coated substantially uniformly with an elastomer of 50 to 150 g/m2.

[0009]

[Embodiment] The nylon 66 fiber forming the airbag according to the present invention means a fiber consisting essentially of polyhexamethylene adipamide polymerized from hexamethylene diamine and adipic acid. Copolyamide fibers containing other copolymer components may be used as long as the properties of Pamide are not impaired.

[0010] The nylon 66 filament used in the present invention can be obtained by a conventional spinning method. That is,
Specifically, nylon 66 chips are melted and passed through a spinneret with circular or non-circular holes.
Spun at ~700 m/min to a total fineness of 1,800 to 5,000 deniers, cooled and solidified the spun filament with cold air, then applied with an oil agent, and taken off with a take-up roll that controls the spinning speed. .

[0011] The taken-off undrawn yarn is usually drawn without being wound up. Specifically, the undrawn yarn is continuously hot drawn at 180°C or higher, preferably 200°C or higher. Stretching is performed in two or more stages, and the stretching ratio is from 3.5 times to 6.
It is in the range of 0 times. The number of single filaments of the thus obtained circular and non-circular cross-sectional shapes ranges from 45 to 25.
0, preferably 70 to 230.

The draft rate during drawing is adjusted so that the denier of each single filament obtained by drawing is 3 to 6 denier. If the single yarn is less than 3 denier,
The loops formed when applying the elastomer to the base fabric obtained by weaving are crushed, and chain-like entanglements between the loops of each single yarn and the elastomer no longer occur, and the peeling resistance between the base fabric and the elastomer is improved. It will be inferior. On the other hand, if the single yarn exceeds 6 denier, the rigidity of the single yarn itself increases and it becomes difficult to entangle with other single yarns, making it difficult to form a loop.

[0013] When the number of single yarns forming a filament is less than 45, the binding force between the single yarns decreases. This is because, for example, since the yarn passes through a process in which tension is applied, such as a twisting process or a weaving process, the entanglements and loops of the filaments are released, thereby reducing the number of entanglements and loops. In addition, if the number of single yarns forming a filament is more than 250, when each single yarn is interlaced and looped using a nozzle that forms interlacing and loops having a certain space, each single yarn is Since the movement of the fluid nozzle is more likely to be restricted, entanglement and loops caused by the fluid nozzle are extremely reduced.

[0014] When intertwining and forming loops between single filaments in the filament having a circular or non-circular cross-sectional shape, the filament is brought into an overfeed state using an air or steam processing nozzle, and then high-pressure air is applied to the filament. A method is used to deal with fluid disturbance by applying a current or air current. At this time, the size and number of loops can be determined by the overfeed rate, processing speed, fluid speed, number of filaments, etc.

By intertwining the filaments and forming loops as described above, when the elastomer is laminated on the base fabric obtained by weaving these filaments, the loops of each single yarn, the base fabric and the elastomer form a chain-like tangle, resulting in favorable adhesion.

Various shapes can be considered for the filament with a non-circular cross-section, but the spinning speed must be 500 m/min or more, which is the same as for the filament with a circular cross-section, and a spinneret with pressure resistance that can be used even at the above-mentioned spinning speed can be manufactured. Therefore, a Y-shaped or C-shaped non-circular cross section is preferable. Note that the Y-shape includes a T-shape that is a modification of this Y-shape.

The nylon 66 filaments obtained by the above method are woven in a weaving process, and the weaving density in this case is within the range of 30 to 60 filaments/inch. When the weaving density is less than 30 threads/inch, the bursting strength of the airbag sheet obtained using the base fabric is low;
If it exceeds 0 lines/inch, the capacity of the base fabric increases, resulting in not only poor storage performance but also poor expansion performance.

[0018] For the laminate that can be used in the airbag according to the present invention, elastomers with good heat resistance, such as chloroprene rubber, chlorosulfonated olefin rubber, fluororubber, etc., and urethane resins are preferably used. When laminating the elastomer or elastomer analog, it is applied to at least one side of the base fabric, and existing methods such as a coating method or a topping method can be used for the lamination method. The adhesion amount of laminate is 50g/m2 to 150g/m2
2, preferably 70g/m2 to 120g/m2
It is. If the laminate is less than 50g/m2, it will not be able to withstand the instantaneous inflation of the airbag;
If the amount is more than 0 g/m2, the foldability of the airbag sheet becomes poor and bulkiness increases, which impairs storage properties, which is not preferable.

[0019]

【Example】

Example 1 Nylon 66 chips with a relative viscosity of 3.50 were melted in a 70φ extruder type spinning machine and spun using a spinneret having a Y-shaped spinning hole. The spun filament was cooled by blowing cold air at 25° C. under the spinneret at a chimney wind speed of 40 m/min. Next, an oil agent was applied and a 3% pre-stretch was applied, followed by multi-stage stretching and relaxation heat treatment. The stretching ratio is 1st stage:
3.0 times, 2nd row: 1.5 times. The temperature of each roller was 60° C. for the pre-stretch roller, 100° C. for the first-stage stretching roller, 200° C. for the second-stage stretching roller, and 225° C. for the relaxation heat treatment roller, and Nelson-type rolls were used for each roller. The obtained filaments were 420 denier and 72 filaments, and the single yarn was about 5.8 denier.

feeding the filament into a nozzle forming a turbulent region with water vapor pressure substantially saturated;
Interlaced and formed loops. Using the fluid-treated yarn thus obtained for the warp and weft, a plain woven fabric with a warp density of 50 threads/inch and a weft thread density of 50 threads/inch was woven. The obtained base fabric was coated with chloroprene rubber at a density of 100 g/m 2 , and then heated and pressed at 180° C. for 3 minutes to obtain a sheet for an airbag. The performance of this airbag sheet was as shown in Table 1.

[0021]

[Table 1]

[0022] Each item was measured using the following method. Bursting strength: Measured according to Mullen method of JIS L-1018 Air permeability: Measured according to JIS L-1096 Adhesiveness: Measured according to JIS K-6328 Foldability: Fold an airbag sheet with a width of 30 cm and a length of 1 m into four. Bulky when made into.

Example 2 The conditions were the same as in Example 1, except that the undrawn yarn spun using a circular spinneret instead of the Y-shaped spinneret in Example 1 was drawn at a total draw ratio of 5.0 times. It was processed to obtain sheets for airbags. The performance of the obtained airbag sheet is shown in Table 2.
It was as shown in .

[0024]

[Table 2]

Comparative Example 1 An undrawn yarn obtained in the same manner as in Example 2 using the circular die was drawn at a drawing ratio of 5.0 times, and the obtained filament was drawn in the same manner as in Example 1 without fluid treatment. Weaving was carried out in the same manner, and the obtained base fabric was coated with rubber to obtain a sheet for an airbag. The performance of this airbag sheet was as shown in Table 3.

[0026]

[Table 3]

As shown in Examples 1 and 2 above, the airbag sheet according to the present invention has excellent bursting properties, adhesive properties, air permeability, and foldability. Regarding the adhesiveness, in Example 1 it was 8Kg/in, and in Example 2 it was 7Kg/in.
in, which is significantly improved over Comparative Example 1, and as a result, in Examples 1 and 2, airbag sheets with excellent bursting strength, air permeability, and foldability were obtained. That is clear.

[0028]

[Effect of the invention] The airbag sheet according to the present invention has
The adhesion between the nylon 66 base fabric and the elastomer has been greatly improved without using adhesives, and even if adhesive is used, the amount is extremely small, so the entire airbag sheet will not harden and the base fabric will not harden. It retains strength and has excellent impact resistance. Furthermore, since the base fabric is less hardened, folding properties are improved, and storage properties and durability are excellent.

Claims (3)

[Claims] Claim 1: In a sheet for an airbag, 45 to 250 single filaments of 3 to 6 deniers made of hexamethylene diamine and adipic acid are bundled, and looped and intertwined nylon 66 filaments are woven at a weaving density of 30 to 60 filaments. An airbag characterized in that the whole or part of one side of a base fabric woven at a speed of 50 to 150 g/m2 and having loops formed on the entire surface is coated almost uniformly with an elastomer of 50 to 150 g/m2. sheet for. 2. The sheet for an airbag according to claim 1, wherein the elastomer is silicone rubber or chloroprene rubber. 3. The airbag sheet according to claim 1, wherein the non-circular cross-sectional shape of the single filament is Y-shaped or C-shaped.