JP2001287609A - Coating composition for air bag, and air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ground fabric for an cur bag excellent in a weight-reducing property, flexibility and compactness, and satisfying flame retardancy and burning velocity provided by the FMVSS302 even in a small applied amount such as 20 g/m2 or less of coating resin-applied amount, and a coating composition for the air bag used for the ground fabric. SOLUTION: This coating composition for the air bag is prepared by adding, (B) an amount within a range less than 5 pts.wt. from 0.1 pts.wt. as a solid component of at least one kind of powder selected from the group comprising cabon black, NiO2, FeO, FeO2, Fe2O3, Fe3O4, CoO2, CeO2, and TiO2 suspended preliminarily in water under the presence of a surfactant, to (A) 100 pts.wt. of solid component in an aqueous silicone emulsion, and the ground fabric for the air bag is provided by applying this composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base fabric for an airbag which is installed to ensure the safety of an occupant in the event of a vehicle collision. More specifically, the present invention relates to an airbag having excellent lightweight, flexibility and compactness. The coating amount of the coating resin is 20 g /
Even such a small amount of m ² or less, the flame retardancy FMVSS302 stipulated, an airbag fabric which satisfies the burn rate, and to a coating composition for an air bag.

[0002]

2. Description of the Related Art Airbags have been increasingly used as occupant protection and safety devices for automobiles. Since the airbag is usually mounted as a module including an inflator case in a narrow place such as a steering wheel or an instrument panel, it is desirable that the storage volume of the airbag be small. For that purpose, use fibers of small fineness as the fibers used for the woven fabric to make the storage volume compact, and change the type and amount of the elastomer applied to the base fabric to maintain the airtightness of the airbag. And so on.

For example, a fiber used for a woven fabric is 940 dt.
ex to 470 dtex base fabric. In addition, the amount of the elastomer resin to be applied and the amount of application are changed from applying 90 to 120 g / m ^{2 of} chloroprene to applying 40 to 60 g / m ^{2 of} the silicone resin. A base fabric is used, and a non-coated type having minute air permeability is used in view of improvement in compactness and economical cost of coating processing.

However, in the recent market, in order to further reduce the weight and size of the airbag, it is required to reduce the weight of the base fabric for the airbag and to soften the texture, and to reduce the cost of the coating process and the cost. There is a demand to reduce the amount of coating to reduce the weight of the coated cloth. However, when the application amount of the silicone composition is reduced, the burning rate increases, and a problem occurs that the burning rate does not satisfy the burning rate determined by FMVSS302.

[0005] As typical conventional techniques for solving this problem, there are JP-A-5-202338, JP-A-7-90777, and JP-A-7-300774. In JP-A-5-202338,
Although a silicone aqueous emulsion is used, since it does not contain a suitable flame retardant, it is difficult to achieve flame retardancy with a small coating amount such as 20 g / m ² or less.

In JP-A-7-90777, flame retardancy is achieved by adding a solid powder of carbon black to a silicone composition having a high viscosity. However, carbon black as a solid powder does not settle in a high-viscosity state, but when added to a low-viscosity state such as an aqueous silicone emulsion, the carbon black sinks to the bottom of the liquid, resulting in a uniform aqueous silicone emulsion. Can not get.

In Japanese Patent Application Laid-Open No. 7-300774, 5 to 10 parts by mass of solid powder acetylene black and Fe ₂ O ₃ are added to 100 parts by mass of the silicone composition to achieve flame retardancy in light application. ing. However, if 5 to 10 parts by mass of acetylene black or Fe ₂ O ₃ as a solid powder is added, secondary aggregation of the solid powder occurs, and the average particle diameter increases. Particles having a large diameter cannot be fixed with silicone, causing a problem that the particles are scattered during sewing of the airbag base fabric and clog in holes of a sewing needle. Furthermore, when 5 parts by mass or more of the powder containing oxygen is added, the powder itself acts as an oxygen supply agent, and the FMVSS3
The burning speed in the 02 test increases.

[0008]

SUMMARY OF THE INVENTION The present invention provides an FMVSS having excellent lightness, flexibility, and compactness even if the coating amount of the coating resin is as small as 20 g / m ² or less.
An object of the present invention is to provide a base fabric for an airbag which satisfies the flame retardancy and burning rate defined by 302, and a coating composition used therefor.

[0009]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, carbon black, NiO, which was previously dispersed in water in a silicone aqueous emulsion in the presence of a surfactant. ₂ , FeO, Fe
_{O 2, Fe 2 O 3,} Fe 3 O 4, CoO 2, CeO 2 and by adding one or more powders selected from TiO _2, to suppress secondary aggregation of the solid powder, the airbag sewing In addition to eliminating powder scattering at the time, the coating composition is applied to a base cloth using fibers having a total fineness of 200 dtex or less at 20 g / m ² or less, so that it has unprecedented compactness. Have found a base fabric for an airbag which satisfies the flame retardancy and burning rate determined by the present invention, and have completed the present invention.

That is, the present invention is as follows. (1) Solid content of (A) silicone aqueous emulsion 10
(B) carbon black, NiO ₂ , FeO, previously dispersed in water in the presence of a surfactant,
FeO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , CoO ₂ , CeO
_{2. A} coating composition for an airbag, wherein one or more powders selected from TiO ₂ and TiO ₂ are added in an amount of 0.1 to less than 5 parts by mass in solid content.

(2) A base for an airbag, wherein the coating composition described in (1) above is applied to a woven fabric composed of fibers having a total fineness of 200 dtex or less at a solid content of 20 g / m ² or less. cloth. (3) An airbag comprising the base fabric for an airbag described in (2). Hereinafter, the present invention will be described in detail.

The aqueous silicone emulsion used in the present invention comprises (a) an organopolysiloxane having a SiC-bonded vinyl group at a terminal unit, (b) an organopolysiloxane having at least three Si-bonded hydrogen atoms,
(C) a catalyst for promoting the addition of a Si-bonded hydrogen atom to an aliphatic multiple bond, (d) an organosilicon compound suitable as an adhesion promoter, (e) a silicone resin, (f) an emulsifier, and (g) water. , At least, and is not particularly limited.

The component (B) used in the present invention is silicone
It is provided as a filler of the coating film,
A carbon fiber that has been previously dispersed in water in the presence of a surfactant
Rack, NiO_Two, FeO, FeO_Two, Fe_TwoO_Three, F
e_ThreeO_Four, CoO_Two, CeO _TwoAnd TiO_TwoChosen from
Powder or two or more powders. Average particle size of powder
Is 20 μm or less, preferably 0.01 to 20 μm,
Preferably, it is 0.02 to 1 μm. Small average particle size
If it is too small, it becomes difficult to disperse the powder, and the average particle size is 20%.
If it exceeds μm, the coating amount is 20 g / m^TwoThe following coatings
The surface of the coated cloth does not become smooth when brushing.

Further, an arbitrary emulsifier can be used in the dispersion water of the powder described above. Preferred emulsifiers are
It is an ionic and nonionic emulsifier. Examples of such emulsifiers include sulfonic acid and its salts that can act as emulsifiers, and alkyl sulfonates, such as sodium lauryl sulfonate, benzene sulfonates substituted with aliphatic hydrocarbon groups, such as sodium dodecyl benzene Sulfonate, naphthalene sulfonate substituted with an aliphatic hydrocarbon group, polyethylene glycol sulfonate and lauryl phosphate, polyethylene oxide, polypropylene oxide, copolymers of ethylene oxide and propylene oxide, stearate and phosphate.

In the present invention, the amount of (B) added is based on 100 parts by mass of the solid content of the aqueous silicone emulsion.
The content is 0.1 part by mass or more and less than 5 parts by mass in solid content, and preferably 1 to 3 parts by mass. When the amount is 5 parts by mass or more,
Secondary agglomeration of the powder occurs. In the case of powder containing oxygen, the powder itself acts as an oxygen supply agent, and the FMVSS3
The burning speed in the 02 test increases. Also,
If the amount is less than 0.1 part by mass, the effect of filling the silicone coating film becomes insufficient.

As the powder dispersion of (B) in the present invention, a commercially available one can be used, and the kind thereof is not limited. Specific examples include "D" manufactured by Degussa-Hüls.
ERUSSOL VU 25 / L ", Dainichi Seika's" AM
Brown 8800 "and" AM Yel "manufactured by Dainichi Seika
low 8150 ", Dainichi Seika's" MF5360 Green ", Dainichi Seika's" MF5460 Blue ", and the like.

Further, the coating composition of the present invention includes:
It may contain known thickeners, flame retardants, and stabilizers in amounts that do not impair the effects of the present invention. In the base fabric for an airbag of the present invention, the coating amount of the coating composition is 20 g / m ² or less in solid content, preferably 5 to 5 g / m ^2.
15 g / m ² . If it exceeds 20 g / m ² , the weight of the base fabric for an airbag and the softness of the hand become insufficient, and the cost of coating increases. On the other hand, if the coating amount is too small, the flame retardancy becomes insufficient.

The fibers constituting the base fabric for an airbag of the present invention are not particularly limited, but fibers mainly composed of polyhexamethylene adipamide are preferable, and particularly, polyhexamethylene adipamide having a melting point of 215 ° C. or more ( Hereinafter, it is referred to as nylon 66 fiber, nylon 66 copolymer (nylon 66/6, nylon 66 / 6I, nylon 66/6).
10) and nylon 66 fiber blended with a polyamide polymer (nylon 6, nylon 610, etc.) are particularly preferred from the viewpoint of heat resistance.

The relative viscosity ηr of sulfuric acid of the fiber mainly composed of nylon 66 is desirably 2.5 to 3.3. ηr is 2.
If it is less than 5, it is difficult to obtain high-strength fiber stably, and η
If r exceeds 3.3, the spinnability tends to be poor due to the progress of gelation accompanying the decrease in fluidity due to high viscosity.
Sulfuric acid relative viscosity ηr of the fiber mainly composed of nylon 66
Is a method of dissolving 1 g of fiber having no oil agent in 95.5% sulfuric acid (100 cc) and measuring it with an Ostwald viscometer in a thermostat at 25 ° C.

Since the base fabric for an airbag of the present invention must satisfy mechanical properties such as tensile strength and tear strength required for operation of the airbag, the single-filament fineness and the total fineness of the fibers constituting the base fabric for an airbag. , Tensile strength and weave fineness (total fineness of warp or weft (dtex) and weave density (book / 2.54c)
m) is an important requirement. The fineness of the single yarn of the fibers constituting the base fabric for an airbag is not particularly limited, but preferably the fineness of the single yarn is 0.5 to 7 dtex, and more preferably 1.1 to 3.3 dtex. . 7dte
If the value exceeds x, the base fabric tends to be hard and the soft texture tends to be inferior. If the value is less than 0.5 dtex, the weaving operation rate tends to decrease due to fluff during fiber production or a stop during high-density weaving.

The total fineness of the fibers refers to the total fineness per unit of the fibers in the warp and weft directions used when constructing the woven fabric. One yarn may be used, or a plurality of yarns may be twisted, plyed, Although it may be in the state of a drawn yarn, the total fineness is preferably 200 dtex or less, more preferably 5 dtex or less.
0 to 170 dtex. If it exceeds 200 dtex, the required compactness cannot be obtained, and if the total fineness is too small, there is a possibility that the pressure-resistant mechanical properties at the time of operating the airbag may not be obtained.

Further, the tensile strength of the fiber also has a great effect on the pressure-resistant mechanical characteristics during the operation of the airbag. The tensile strength of the fiber is preferably 5.7 cN / dtex or more. The weave fineness (product of the total fineness (dtex) of the warp or weft and the weave density (book / 2.54 cm)) of the base fabric for an airbag is preferably 16,000 or less, more preferably 10,000 to 160.
00. If the weave fineness exceeds 16000, it becomes an ultra-high-density woven fabric, and there are many stops during weaving, and stable weaving cannot be performed. If the weave fineness is too small, the tensile and tear properties of the obtained base fabric become low, and as an airbag. The required tensile and tear strength may not be obtained.

The form of the base fabric is preferably a woven fabric. As the woven fabric, woven fabrics such as plain weave, lattice weave, twill weave, and satin weave are used. The ratio of the number of the woven fabrics in the warp and weft directions is preferably the same for the warp and weft, but may be around several. The weaving of the woven fabric may use existing air jet weaving, water jet weaving, rapier weaving, etc., and is not particularly limited, but it is preferable to perform non-sizing air jet weaving from the simplicity of the process after weaving. .

As a method for applying the coating composition of the present invention, an existing coating device and spraying device may be applied, and there is no particular limitation.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples. Parts represent parts by mass. The evaluation method is as follows. (1) Burning speed The FMVSS302 method (horizontal method) was used.

(2) Compactness A 100 cm × 100 cm coated cloth is 10 cm ×
Fold it to 10 cm and measure the bulk when a load of 1000 g is applied. Comparative Example 4 is used as a standard product, and the relative value is shown when the bulkiness is set to 100. (3) Stainability In accordance with JIS L 0849, the degree of coloring of the friction white cloth was visually determined.

The results were as follows: ：: no coloring, Δ: little coloring, ×:
It was expressed as "colored many". [Example 1] Silicone aqueous emulsion ("DEHENSIVE 38197" manufactured by Asahi Kasei-Waker Co., Ltd.)
VP ") 82 parts, 7.5 parts of an organopolysiloxane having at least three Si-bonded hydrogen atoms (" V20 "manufactured by Asahi Kasei-Waker Co., Ltd.), an organosilicon compound suitable as an adhesion aid (Asahi Kasei-Waker Co., Ltd.) "HF
86 ") was stirred and mixed with 7.5 parts of an aqueous carbon black dispersion (" DERUSS "manufactured by Degussa-Hüls).
OL VU 25 / L "), and stir and mix.
A coating composition was obtained. (Carbon black solid content) / (composition total solid content) = 0.015.

[0028] The above coating composition is coated with nylon 66
The base fabric having a total fineness of 155 dtex and having a weave density (warp × weft) of 91 × 91 / 2.54 cm was coated with a knife coater so as to have an application amount of 8 g / m ² . After coating, water was removed at 130 ° C. for 2 minutes and vulcanized at 180 ° C. for 1 minute. The silicone of the obtained coated cloth was uniformly applied.

Example 2 Silicone aqueous emulsion ("DEHENSIVE3" manufactured by Asahi Kasei-Waker Co., Ltd.)
8197 VP "), an organopolysiloxane having at least three Si-bonded hydrogen atoms (Asahi Kasei Corporation)
7.5 parts of "W20" manufactured by Wacker Co., Ltd., and 7.5 parts of an organic silicon compound ("HF86" manufactured by Asahi Kasei-Waker Co., Ltd.) as an adhesion aid were mixed by stirring.
Aqueous bengara dispersion (“AM Brown” manufactured by Dainichi Seika)
8800 ") was added, and the mixture was stirred and mixed to obtain a coating composition. (Bengara solid content) / (composition total solid content) = 0.011.

Example 1 The above coating composition was prepared using a knife coater so that the coating amount was 10 g / m ^2.
The same base cloth was coated. After coating, 1
Water was removed at 30 ° C. × 2 minutes, and then vulcanized at 180 ° C. × 1 minute. The silicone of the obtained coated cloth was uniformly applied. [Comparative Example 1] Silicone aqueous emulsion ("DEHENSIVE 38197 V" manufactured by Asahi Kasei-Waker Corporation)
P ") 82 parts, 7.5 parts of an organopolysiloxane having at least three Si-bonded hydrogen atoms (" V20 "manufactured by Asahi Kasei-Waker Co., Ltd.), an organosilicon compound suitable as an adhesion promoter (Asahi Kasei-Waker Co., Ltd.) "HF8
6)) To a mixed solution obtained by stirring and mixing 7.5 parts, an aqueous red bengara dispersion (“AM Brown 8800” manufactured by Dainichi Seika)
7.5 parts were added and mixed with stirring to obtain a coating composition. (Bengala solids) / (composition total solids) = 0.0
80.

Example 1 The above coating composition was prepared using a knife coater so that the coating amount was 10 g / m ^2.
The same base cloth was coated. After coating, 1
Water was removed at 30 ° C. × 2 minutes, and then vulcanized at 180 ° C. × 1 minute. The silicone of the obtained coated cloth was uniformly applied. [Comparative Example 2] Silicone aqueous emulsion ("DEHENSIVE38197 V" manufactured by Asahi Kasei-Waker Corporation)
P "), 84 parts, 7.7 parts of an organopolysiloxane having at least three Si-bonded hydrogen atoms (" V20 "manufactured by Asahi Kasei-Waker Co., Ltd.), an organosilicon compound suitable as an adhesion promoter (Asahi Kasei-Waker Co., Ltd.) "HF8
6)) was mixed with 7.7 parts of a mixed liquid, and carbon black powder (“Printex” manufactured by Degussa-Hüls) was added.
L ") 0.6 part was added, stirred and mixed to obtain a coating composition. (Solid content of carbon black) / (total solid content of the composition) = 0.01.

The above-mentioned coating composition was coated on the same base fabric as in Example 1 using a knife coater so that the coating amount was 8 g / m ² . After coating, 13
Water was removed at 0 ° C. × 2 minutes, and then vulcanized at 180 ° C. × 1 minute. The silicone of the obtained coated cloth was uniformly applied. Comparative Example 3 The same coating composition as in Example 1 was coated with the coating composition of Example 1 using a knife coater so that the coating amount was 40 g / m ² . After coating, water was removed at 130 ° C for 2 minutes.
Vulcanized in 1 minute. The silicone of the obtained coated cloth was uniformly applied.

Comparative Example 4 The coating composition of Example 1 was woven with a knife coater using a nylon 66 fiber having a total fineness of 470 dtex and a weaving density (warp × weft).
46x46 / 2.54cm base cloth, 40g /
m ² . After coating,
Water was removed at 130 ° C. for 2 minutes, and then vulcanized at 180 ° C. for 1 minute. The silicone of the obtained coated cloth was uniformly applied.

Table 1 summarizes the evaluation results of the above Examples and Comparative Examples.

[0035]

[Table 1]

[0036]

According to the present invention, when the airbag is sewn, the powder, which is a silicone filler, is not scattered, the lightness, flexibility, and compactness are excellent, and the coating amount of the coating resin is 20 g / m ² or less. Even, FMVSS30
2 can provide an airbag base fabric having a combustion speed determined by the airbag.

Claims (3)

[Claims] 1. A method according to claim 1, wherein (B) carbon black, NiO ₂ , and (B) water-dispersed in advance in the presence of a surfactant with respect to 100 parts by mass of the solid content of the aqueous silicone emulsion.
FeO, FeO ₂ , Fe ₂ O ₃ , Fe ₃ O ₄ , Co
An airbag coating composition, wherein one or more powders selected from O ₂ , CeO ₂ and TiO ₂ are added in an amount of 0.1 to 5 parts by mass as solid content. 2. A base for an airbag, wherein the coating composition according to claim 1 is applied to a woven fabric composed of fibers having a total fineness of 200 dtex or less at a solid content of 20 g / m ² or less. cloth. 3. An airbag comprising the base fabric for an airbag according to claim 2.