JP3248493B2 - Airbag - Google Patents

Abstract

PURPOSE:To obtain an ultraviolet-curing coating composition which can cure within a short time, therefore can give air bags at high productivity at a low running cost, has excellent self-adhesiveness, can bond tightly and stably to a base cloth of, for example, polyamide or polyester and can give a cured film free from surface tackiness. CONSTITUTION:This coating composition is prepared by mixing an organopolysiloxane (A) having at least two hydroxyl groups in the molecule with an organosilicon compound of the formula (wherein R<1> and R<2> are each a 1-8C alky; (a) is 0 or 1; (b) is 2 or 3; (c) is 0, 1 or 2; and a+b+c=4), or its partial hydrolyzate (B), a mercaptoorganopolysiloxane (C) having at least two mercapto groups in the molecule and used in such an amount as to give 0.1-20 mercapto groups per propenyl group of component B, a curing catalyst (D), and a sensitizer (E).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag obtained by forming a cured film of an ultraviolet-curable coating composition for an airbag having good adhesion and no surface tackiness on an airbag base fabric.

[0002]

2. Description of the Related Art In recent years,
For example, an airbag is used which is folded into a handle of an automobile or the like and opened between the handle and the human body by a shock such as a collision to relieve an impact on the human body. This airbag is generally formed of nylon cloth coated with chloroprene. However, the heat resistance and weather resistance of chloroprene rubber are insufficient, and there is a problem that the life of the airbag is short.

[0003] Further, in order to make the airbag less susceptible to fire and blast generated in the event of a collision of an automobile or the like, it is necessary to impart flame retardancy to the airbag, and a cloth coated with chloroprene rubber is required. In the produced conventional airbag, since the chloroprene rubber does not have sufficient flame retardancy, a silicone flame retardant is further coated on a portion to be exposed to the blast.

On the other hand, in the case of an airbag coated with silicone rubber, it is possible to impart flame retardancy to the silicone rubber itself by adding a known flame retardant to the silicone rubber. There is an advantage that there is no. Therefore, recently, silicone rubber coating agents having excellent heat resistance and weather resistance have been attracting attention as coating agents for airbags.

However, currently used silicone rubber coating agents are heat-curable and room temperature condensation-curable, and require a heating device or require a long time for curing. There is a problem that a space for storing the cloth is required.

The present invention has been made in view of the above circumstances,
UV curing coating composition for airbags that does not require a heating device, has a short curing time, has excellent adhesion to airbag base fabrics such as polyamide and polyester, and has no surface tackiness. Provided is an airbag formed with a cured film of a product.

[0007]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies in order to achieve the above object. As a result, (A) an organopolysiloxane having at least two vinyl groups in one molecule (B) a mercapto group-containing organopolysiloxane having at least two mercapto groups in one molecule, and having an amount of 0.1 to 20 mercapto groups per one vinyl group of the component (A). A coating composition comprising a siloxane and (C) a sensitizer has UV curability or UV-condensation curability, and has a property of curing in a short time by irradiating ultraviolet light. The cured film is coated on the base fabric for the airbag so as to have a thickness of 50 to 200 μm, and is cured by ultraviolet rays, so that it is uniformly and firmly adhered to the base fabric surface in a short time,
Further, the present inventors have found that an airbag formed with a silicone rubber film having excellent surface tackiness and flame retardancy can be obtained, and thus the above composition is effective as a coating composition for an airbag. Was.

Hereinafter, the present invention will be described in more detail. The ultraviolet curable coating composition for an airbag according to the present invention comprises the following components (A), (B) and (C). (A) an organopolysiloxane having at least two vinyl groups per molecule; (B) at least 2 organopolysiloxanes per molecule.
And the vinyl group 1 of the component (A)
Mercapto group-containing organopolysiloxane in an amount of 0.1 to 20 mercapto groups per unit; and (C) a sensitizer.

Here, as the organopolysiloxane having at least two vinyl groups in one molecule of the component (A), known organopolysiloxanes can be used. For example, a group represented by the following general formula (1) can be used. Those containing two or more can be given.

[0010]

Embedded image (Wherein, R ^{1 to} R ⁴ are the same or different unsubstituted or substituted monovalent hydrocarbon groups, a is 1, 2 or 3, b and c are each 0, 1, or 2, a + b + c = 3,
d is an integer of 5 or more. )

In the above formula (1), the unsubstituted or substituted monovalent hydrocarbon group of R ^{1 to} R ⁴ preferably has 1 to 8 carbon atoms. Examples of such a monovalent hydrocarbon group include an alkyl group such as a methyl group, an ethyl group, and a propyl group, a vinyl group,
Alkenyl group such as allyl group, aryl group such as phenyl group and tolyl group, cycloalkyl group such as cyclohexyl group, and part or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms, cyano groups, etc. Chloromethyl group, trifluoropropyl group, cyanoethyl group and the like.

The organopolysiloxane is preferably a linear one in which both ends of the molecular chain are blocked with vinyl groups, and has a viscosity at 25 ° C. of 25 to 500,000 c.
s, particularly preferably 1,000 to 100,000 cs. Further, as the organopolysiloxane of the component (A), a varnish having a branched structure may be used.

[0013] In the coating composition of the present invention,
The component (B) mercapto group-containing organopolysiloxane reacts with the vinyl group in the above component (A) when the coating composition of the present invention is irradiated with ultraviolet rays to form a crosslink. Is to increase the degree of polymerization to a raw rubber-like viscosity so that the initial sealing property is exhibited.

Examples of such an organopolysiloxane include the following.

[0015]

Embedded image (In the formula, m is 3 or more, n, p, q is 0 or more, and r is an integer of 2 or more.)

The mercapto group-containing organopolysiloxane may be used alone or in combination of two or more.

The sensitizer of the component (C) is compounded to accelerate the reaction between the vinyl group in the component (A) and the mercapto group in the component (B) under ultraviolet irradiation. Specifically, acetophenone, propiophenone,
Benzophenone, xanthol, fluorein, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-methylacetophenone, 3-pentylacetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-
Allyl acetophenone, p-diacetylbenzene, 3-
Methoxybenzophenone, 4-methylbenzophenone,
4-chlorobenzophenone, 4,4-dimethoxybenzophenone, 4-chloro-4-benzylbenzophenone,
3-chloroxantone, 3,9-dichloroxantone, 3-chloro-8-nonylxantone, benzoin, benzoin methyl ether, benzoin butyl ether, bis (4-dimethylaminophenol) ketone,
Benzyl methoxy ketal, 2-chlorothioxanthone and the like.

The amount of component (B) is from 0.1 to 20 mercapto groups per vinyl group of component (A).
The amount is particularly 0.5 to 5, and the amount of the component (C) is 0.01 to 10 parts, particularly 0.05 to 5 parts, per 100 parts of the component (A) (parts by weight, the same applies hereinafter). It is preferable to use a part.

When the component (A) has a hydroxyl group blocked at both terminals, the curing catalyst of the following component (D) is used in an amount of 0.01 to 10 parts, preferably 0.1 to 5 parts, per 100 parts of the component (A). It is recommended to mix parts.

That is, as the curing catalyst of the component (D), for example, lead-2-ethyl octate, dibutyltin diacetate, dibutyltin dilaurate, butyltin tri-2-ethylhexoate, iron-2-ethylhate Xoate, cobalt-2-ethylhexoate, manganese-2-ethylhexoate, zinc-2-ethylhexoate, stannous caprylate, tin naphthenate, tin oleate, tin butylate,
Metal salts of organic carboxylic acids such as titanium naphthenate, zinc naphthenate, cobalt naphthenate, and zinc stearate, and organic compounds such as tetrabutyl titanate, tetra-2-ethylhexyl titanate, triethanolamine titanate, and tetra (isopropenyloxy) titanate Organic titanium compounds such as titanates, organosiloxytitanium and carbonyltitanium; alkoxyaluminum compounds; 3-aminopropyltriethoxysilane; aminoalkyl-substituted alkoxysilanes such as N- (trimethoxysilylpropyl) ethylenediamine; hexylamine;
Amine compounds such as dodecylamine phosphate and salts thereof, quaternary ammonium salts such as benzyltriethylammonium acetate, lower fatty acids of alkali metal salts such as potassium acetate, sodium acetate and lithium oxalate; dialkyls such as dimethylhydroxyamine and diethylhydroxyamine Examples thereof include hydroxyamine, tetramethylguanidine, a guanidyl compound represented by the following formula, and a guanidyl-containing silane or siloxane.

[0021]

Embedded image

Of these, guanidine compounds, guanidyl group-containing silanes, and siloxane compounds are particularly preferred because they promote the curing reaction well and have an adhesion improving function. One of these curing catalysts may be used alone, or two or more thereof may be used in combination.

When the composition of the present invention thus obtained is irradiated with ultraviolet rays, it cures in a short time to give a rubber elastic body, and is particularly excellent in thin film curability in units of 50 to 200 μm.

Further, the obtained rubber elastic body has excellent heat resistance, weather resistance and low-temperature characteristics, which are characteristics of silicone rubber, so that it can be used in a wide range of fields.

The coating composition of the present invention preferably contains a filler. The addition of the filler can increase the viscosity of the coating composition to improve workability during coating. Physical properties such as hardness, tensile strength and elongation of the object can be improved. Examples of such a filler include fumed silica, calcined silica, precipitated silica, fumed titanium oxide, carbon black, calcium carbonate, diatomaceous earth, calcium silicate, and these as organochlorosilanes, polyorganosiloxane, hexamethyldisilazane. And the like, and the like.

The amount of the filler is preferably 300 parts or less based on 100 parts of the component (A). If the amount exceeds 300 parts, the fluidity of the composition becomes poor or mechanical strength is obtained. May not be possible.

Further, the coating composition of the present invention includes:
Further, a one-component condensation type adhesion aid can be added for the purpose of improving the adhesion. Examples of such an adhesion aid include γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, and the like.

The coating composition of the present invention is produced by kneading the above components in a dry atmosphere, and is used to coat the above components on various airbag base fabrics such as nylon. It is preferable to use it after dissolving it in an appropriate organic solvent. Specifically, benzene, toluene, xylene and the like can be used as the organic solvent.

The present invention also provides an airbag in which a cured film of the above-mentioned coating composition is formed on an airbag base fabric. The airbag substrate on which the cured film of this coating composition is formed is provided. As cloth, nylon,
Fibers such as tetron, vinylon, polyester, and polyurethane or a woven fabric made of the fibers can be used, and among them, nylon and polyester are particularly preferable.

The composition can be coated on the base fabric by calendering, knife coating, brushing, dip coating, spraying, or the like. When the composition is in a solid form, the composition is applied as described above. Dissolve in organic solvent, likewise, knife coating,
It is preferable to employ a coating method such as brushing, dip coating, spraying and the like. Further, the coating thickness is preferably set to 50 to 200 μm.

[0031]

EXAMPLES The present invention will be described below in detail with reference to examples and comparative examples, but the present invention is not limited to the following examples. In each example, the viscosity indicates a value at 25 ° C.

Example 1 Both ends were blocked with a trivinyl group, 100 parts of polydimethylsiloxane having a viscosity of 1,500 cp, 20 parts of fumed silica, and mercapto having a viscosity of 35 cp represented by the following formula (2): 5 parts of organopolysiloxane containing group and 2,2-diethoxyacetophenone 1
Was added and kneaded in a dry atmosphere to prepare a coating composition 1.

[0033]

Embedded image

Comparative Example 1 Dimethylsiloxane Unit 9
100 parts by weight of an organopolysiloxane having a relative viscosity of 2.8 in a 25% by weight toluene solution containing 9.8 mol% and methyl vinyl siloxane unit 0.2 mol% and having a molecular chain terminal blocked with a dimethyl vinyl siloxane group. , The specific surface area of which is surface treated with trimethylsilyl group is 230 m ²
/ G of hydrophobic silica and 1.0 part of dimethylpolysiloxanediol having a molecular chain end blocked with a silanol group were added, and heat-treated at 180 ° C. for 2 hours in a kneader to prepare a compound.

Next, 3.5 parts of organic peroxide 2,4-dichlorobenzoyl peroxide having a pure content of 50% was added to 100 parts of this compound, kneaded uniformly, and thinly dispensed with a three-roll mill. Was dissolved in toluene to prepare a toluene solution having a silicone content of 25% by weight. To 100 parts of this toluene solution was added the formula (C ₂ H ₅ O) ₃ Si (CH ₂ )
₃ Coating composition 2 was prepared by adding 5 parts of an isocyanate group-containing silane represented by NCO to 100 parts of the solid component of the toluene solution.

The above coating composition 1 was prepared to have a linear density of 18
One side of a plain woven nylon fiber woven fabric of × 17/25 mm is coated with a thickness of 100 μm (when dry) and irradiated with a high-pressure mercury lamp of 80 W / cm at a distance of 10 cm, and the irradiation energy becomes ² J / cm ^2. And cured.

For comparison, the sample was coated with the composition 2 in the same manner as the coating composition 1, air-dried at 25 ° C. for 30 minutes, and cured by heating at 180 ° C. for 7 minutes.

Next, the cured physical properties of these samples were measured. As shown in FIG. 1, a predetermined portion of the surface of the cured silicone film was scratched with a stainless steel device under a load of 200 g, and the number of times of the scratching until the cured silicone film was completely peeled off from the nylon fiber woven fabric was compared with that of the nylon base fabric. Adhesive properties. Each sample was kept at 85 ° C. and 95% humidity.
After keeping each% RH state for one week and swelling each sample, the same adhesion test as above was performed to measure the adhesion after wetting. In FIG. 1, 1 is a nylon fiber woven fabric, 2 is a silicone cured film, 3 is a scratching device made of stainless steel, and 4 is a weight for applying a load to the device 3.

As shown in FIG. 2, the surfaces of the nylon fiber woven fabric 1 covered with the silicone cured film 2 are adhered to each other, and are applied at 25 ° C. under a load of 20 kgf / cm ^2.
After crimping for 2 hours, cut into 2.5cm width to make a test piece,
The 180-degree peel test was performed at a speed of 10 mm / min using a tensile tester to measure the load, thereby examining the tackiness of the surface of the cured silicone film. Table 1 shows the results.

[0040]

[Table 1]

[0041]

The coating composition for an airbag of the present invention is a UV-curable type, which cures in a short time because it is a UV-curable type, has high productivity, is low in running cost, is excellent in self-adhesiveness, and is polyamide and polyester. It shows strong and stable adhesion to a base fabric such as that described above, and the cured film of this coating composition has no surface tack.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a cured physical property test in Examples and Comparative Examples of the present invention.

FIG. 2 is an explanatory diagram of a surface tackiness test in Examples and Comparative Examples of the present invention.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI B60R 21/16 B60R 21/16 B29K 83:00 B29K 83:00 (72) Inventor Takashi Miyoshi 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Shin-Etsu Chemical Co., Ltd. Silicone Electronic Materials Research Laboratory (56) References JP-A-60-110752 (JP, A) JP-A-5-98579 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D06M 15/00-15/715 C09D 183/00-183/16

Claims (2)

(57) [Claims] 1. An airbag fabric comprising: (A) an organopolysiloxane having at least two vinyl groups in one molecule; and (B) having at least two mercapto groups in one molecule. (A) a mercapto group-containing organopolysiloxane in an amount of 0.1 to 20 mercapto groups per one vinyl group of the component; and (C) a UV curable coating for an airbag, which comprises a sensitizer. An airbag formed by forming a cured film of the composition to a thickness of 50 to 200 μm. 2. The airbag according to claim 1, wherein the organopolysiloxane as the component (A) is one having both ends blocked with a trivinylsilyl group.