JPH04151344A - Sheet for air bag - Google Patents

Abstract

PURPOSE:To improve the quality of an air bag sheet in respect of stowage, expansion and adaptability to environment by forming the sheet with a fabric of synthetic fiber multi-filament threads displaying specific values of strength and total size, and having at least one side thereof coated with a silicone resin composite. CONSTITUTION:The air bag sheet in the title comprises a fabric of synthetic fiber multi-filament threads having strength equal to or above 8.0g/denier and a total size of 200 to 1500 denier, and at Least one side thereof coated with a silicone resin composite. The synthetic fiber multi-filament thread is a single synthetic fiber of synthetic resin such as a polyamide fiber including nylon 6, 66 or 46, and a total aromatic polyamide fiber (alamide fiber) represented by paraphenylene terephthal amide, or a thread made of combined filament yarn containing a mixture of two or more of the aforesaid fibers. Also, the silicone resin composite is high polymer having a main skeleton of siloxane bonding represented by dimethyl polysiloxane methylvinyl polysiloxane or the like.

Description

[Detailed description of the invention] (Industrial application field) The present invention is flexible and has excellent storage and expandability.

The present invention relates to a sheet that can provide an airbag with good mechanical properties and excellent environmental resistance.

(Conventional technology) As a safety device for protecting automobile occupants.

Air bag systems are being put into practical use.

The airbag in this airbag system is stored in a very small place such as a steering wheel until it is activated, and when it needs to be activated, it must be able to inflate to a predetermined size in a very short period of time. ,
In addition, it is necessary to have a highly reliable product that can function with the same performance as the original when one action is required even after one year. Currently, airbags are made of synthetic fiber multifilament yarn.

Fabrics mainly using nylon 66 filament,
II.In order to improve flammability and heat resistance and prevent gas leakage, it is generally provided by sewing a sheet covered with chloroprene rubber.

However, chloroprene rubber is heat resistant.

Poor environmental resistance such as ozone resistance or moisture resistance.

There are concerns that problems such as embrittlement and decomposition may occur during long periods of storage in the interior of a car, where it can be exposed to a wide range of conditions. In addition, the specific gravity is as high as approximately 1.23, which is disadvantageous in the direction of weight reduction.

The curing time of the vulcanization process during coating on textiles requires 15 to 30 minutes, and processing efficiency is also poor.

(Problems to be Solved by the Invention) The present invention was made in view of the current situation, and is intended to maintain the mechanical properties of an airbag.

It can be stored compactly and has excellent deployability during one operation.

The object of the present invention is to obtain an airbag sheet that can provide a highly reliable airbag even when placed in a harsh environment for a long period of time.

(Means for Solving the Problems) The present invention achieves the above object and has the following configuration.

That is, the present invention is characterized in that at least one side of a fabric made of synthetic fiber multifilament yarn having a strength of 8.0 g/denier or more and a total fineness of 200 to 1500 denier is coated with a silicone-based resin composition. The gist of this paper is a sheet for airbags.

The present invention will be explained in detail below.

The synthetic fiber multifilament yarn used in the present invention is
Polyamide fibers such as nylon 6.66.46 and fully aromatic polyamide fibers (aramid fibers) such as paraphenylene terephthalamide.

Polyester fibers represented by polyethylene terephthalate, fully aromatic polyester fibers, polyolefin fibers such as ultra-high molecular weight polyethylene, single fibers of synthetic fibers such as vinylon fibers, polyoxymethylene fibers, polyether ether ketone fibers, or two of these fibers. It refers to a yarn made of a mixed yarn that is a combination of two or more fibers, and also includes yarns with irregular cross sections such as flat yarns, and yarns that have been subjected to bulk processing.

This yarn contains heat stabilizers, antioxidants, light stabilizers, smoothing agents, plasticizers, thickeners, pigments, etc. in order to improve productivity and properties in the manufacturing and processing processes. It is also possible to use materials containing various additives such as gloss imparting agents or flame retardants.

The synthetic fiber "full filament yarn" of the present invention is.

Strength is 8.0g/denier or more, total fineness is 20
It needs to be 0 to 1500 deniers. If the strength is less than 8.0 g/denier, mechanical properties such as tensile strength, bow tear strength, and bursting strength required for an air bag sheet cannot be fully satisfied. If the total fineness is less than 200 denier, it is necessary to increase the density of the fabric in order to maintain the above mechanical properties,
The weavability of the weaving property deteriorates, and the fabric becomes stiff in texture, making it impossible to achieve the object of the present invention. Moreover, when the total fineness exceeds 1500 deniers, the thickness of the fabric increases, the fabric itself becomes loose, and the amount of processing agent such as resin for preventing gas leakage increases.

As a result, the weight of the airbag itself becomes large, and the storability becomes poor, which is not suitable for the purpose of the present invention.

The woven fabric of the present invention is made of one or more types of synthetic fiber filament yarns, and its texture can be plain weave, twill weave, satin weave, or variations of these textures, and there are no particular limitations. Multi-axial tissues can also be used.

In addition, in order to improve the productivity of the woven fabric or to improve the adhesion with the resin that will be coated later, twisting, interlacing, gluing, etc. may be performed in the preparation process before weaving. Later, in order to remove the oil agent applied during the production of the synthetic fiber multifilament yarn and the sizing agent applied in the preparation process before weaving, the sheet is subjected to a scouring process or a treatment for stabilizing the performance of the sheet 2. For example, A flame retardant treatment or the like may be performed.

The silicone resin composition used in the present invention is a polymer with a main skeleton of siloxane bonds, such as dimethylpolysiloxane, methylvinylpolysiloxane, phenylmethylpolysiloxane, phenylvinylpolysiloxane, etc. It also includes copolymers and three-dimensionally crosslinked polymers. In particular, linear polymers of organosiloxane bonds that have rubber-like elastic properties are added with polymeric groups such as vinyl groups.

More preferred for the present invention are those into which a phenyl group, fluorine, or nitrile group is introduced because they have good heat resistance and cold resistance.

Further, the silicone resin composition may contain various catalysts and additives used to improve productivity or improve properties in the polymerization process or processing process. For example, various organic catalysts, inorganic catalysts, thermal stabilizers, antioxidants,
Antistatic agent, light stabilizer, smoothing agent 2 surface modifier, plasticizer,
Thickeners, pigment brighteners, flame retardants, fillers, etc. can be used.

The silicone-based resin composition is coated on the fabric by applying the silicone-based resin composition to the surface of the fabric by a coating method or a lamination method, and then drying and curing using a hot air circulation tenter or the like. Coating methods include the knife coating method represented by the floating coating method, the roll coating method represented by the direct roll coating method, the gravure coating method represented by the direct gravure coating method, and the transfer coating method.

Dip coating method, air doctor coating method, rod coating method, calendar coating method, curtain coating method, extrusion coating method, vapor deposition method, etc. can be adopted, and as lamination method, adhesive method, heat fusion method, etc. can be adopted. .

The present invention has one or more configurations.

(Function) If the fabric of the present invention is made of synthetic fiber multifilament yarn with a single strength of 8.0 g/denier or more and a total fineness of 200 to 1500 deniers as the base fabric, the tensile strength required for an airbag can be achieved. It is possible to obtain a fabric that satisfies mechanical properties such as strength and tear strength, and since the silicone resin composition is coated on at least one side of the fabric,
Compared to conventionally used sheets coated with chloroprene rubber, it is possible to obtain airbag sheets that have superior environmental resistance such as heat resistance, ozone resistance, and moisture resistance, and are also lightweight and flexible. can.

(Example) Next, the present invention will be explained in more detail with reference to 9 Examples. In the Examples, the measurement and evaluation of the performance of the sheet was carried out in the standard state as well as the measurement after being left under the following three conditions. An evaluation was conducted and the environmental resistance was evaluated.

(A) Moisture resistance evaluation After being left in a constant temperature and humidity chamber at 50°C and 95% RH for 500 hours,
Each test was carried out after being left in standard conditions for 24 hours or more.

Regarding tensile strength and tear strength, the ratio before and after standing under the conditions was expressed as a percentage, and the retention rate (%) was obtained.

(B) Heat resistance evaluation After being left in a dryer at 110°C for 1000 hours.

Each test was carried out after being left in standard conditions for 24 hours or more.

Regarding tensile strength and tear strength, the ratio before and after standing under the conditions was expressed as a percentage, and the retention rate (%) was obtained.

(C) Ozone resistance evaluation After being left in an atmosphere containing 400 ppm of ozone at 40° C. for 200 hours, it was left in standard conditions for 24 hours or more and subjected to each test.

Regarding tensile strength and tear strength, the ratio before and after standing under the conditions was expressed as a percentage, and the retention rate (%) was obtained.

Measurement of each test item was performed according to the method shown below.

(1) Measurement of weight per 1 m'' according to JIS L-10966, L2 (2) Measurement of thickness according to JIS L-10966, 3 (3) Tensile strength JIS L-10966, 12, 1A method (strip method) Measured at 3cm width (4) Tear strength Measured using JIS L-10966, 15, 1A-1 method (single tongue method) (5) Flexibility JIS L-10966, 19, IA method (45°
(6) Air permeability Measured by JIS L-10966, 27, IA method (7) Tackiness Two samples of size 10 cm x 10 cm were collected,
After placing the resin surfaces on top of each other and placing a load of 5 kg on them and leaving them in a dryer at 80°C for 1 hour, the peeling state of the overlapped parts of the samples was observed.

Evaluation based on the following ranking: 3: No tack and peels 2: Peels off but is sticky 1: There are parts where the resin adheres and does not peel (8) Flammability Evaluated by FMVSS-302 (9) Abrasion strength JIS L-10216, 12 taper type wear tester using wear wheels NQ, H38.

A load of 500 g was applied and the surface condition was observed after abrasion 300 times.

Example 1 Nylon 66 chips were melt-spun and drawn to obtain a nylon 66 yarn having a strength of 10.0 g/denier, a single fiber fineness of 5 denier, and a total fiber size of 840 denier. Using this thread, a fabric with a flat weave having both a warp density and a weft density of 25 threads/inch was obtained.

Next, the fabric was immersed in a treatment solution consisting of a 15% solution of flame retardant CG-5 (manufactured by Nicca Chemical Co., Ltd.), and a squeeze ratio of 60 was applied using a mangle.
%, and then dried at 120° C. for 1 minute. Subsequently, a silicone resin composition having the formulation shown in Formulation 1 below was applied to one side of the fabric to a thickness of 100 μm by knife coating.

After drying at 120°C for 1 minute, curing was performed at 185°C for 2 minutes to obtain an airbag sheet having a warp and weft density of 27 pieces/inch.

Formulation-1> Instead of curing, chloroprene rubber of the following formulation-2 was coated and dried.

Other than curing at 160°C for 30 minutes.

A sheet of Comparative Example 1 was obtained in the same manner as in Example 1.

Formula-2> Magnesium oxide [Filler] 5 parts Calcium carbonate [Filler 3 10 parts Antimony trioxide [Flame retardant] 10 parts The performance evaluation results of Example 1 and Comparative Example 1 are shown in Table 1.

Table 1 (Continuation of Table 1) As is clear from Table 1, Example 1 is superior to Comparative Example 1 in both initial performance and environmental resistance. That is, in terms of initial performance, when the same base fabric is coated with the same thickness, Example 1 has a smaller basis weight and is softer.

It also has good tackiness. In addition, in the moisture resistance evaluation, heat resistance evaluation, and ozone resistance evaluation, Example 1 had a high retention rate of tensile strength and tear strength, and did not harden.
It remains strong against friction. On the contrary, Comparative Example 1
was hardened in the environmental resistance evaluation test, and the numerical value in the cantilever method of flexibility test was also high, and the coating resin was partially peeled off during the abrasion test process, making the threads visible.

Example 2 In Example 1, the strength was 10.0 g/denier.

Instead of using nylon 66 yarn with a single yarn fineness of 5 denier and a total fineness of 840 denier to make a woven fabric with a warp and weft density of 25 threads/inch, and a sheet with a warp and weft density of 27 threads/inch after processing. Using polyester fiber yarn with a strength of 8.4 g/denier, a single yarn fineness of 4 denier, and a total fineness of 500 denier, a woven fabric with a warp and weft density of 45 yarns/inch was made, and a warp and weft density of 49 yarns/inch after processing. An airbag sheet was obtained in the same manner except for the following steps.

The performance evaluation results of Example 2 are shown in Table 2.

Similar to Example 1, it has excellent performance as an airbag sheet.

(Margin below) Table (Continuation of Table 2) (Effects of the invention) The present invention has a structure in which at least one side of a fabric made of synthetic fiber multifilament yarn with excellent strength is coated with a silicone resin composition. However, according to the present invention having such a configuration, flexibility, moisture resistance, and heat resistance are achieved.

It is possible to obtain an airbag sheet with excellent ozone resistance, etc., and to provide an airbag with excellent storage properties, deployability, and environmental resistance.

Claims (1)

[Claims] (1) Air characterized by being made of a fabric made of synthetic fiber multifilament yarn having a strength of 8.0 g/denier or more and a total fineness of 200 to 1500 denier, at least one side of which is coated with a silicone-based resin composition. Bag sheet.