JP2885003B2 - UV curable coating composition for airbag and airbag - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultraviolet-curable coating composition for airbags which can form a silicone cured film having good adhesion and no surface tackiness on a base fabric for airbags. The present invention relates to an airbag in which a cured film is formed 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,
An airbag 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 can form a silicone rubber film without surface tackiness. It is an object of the present invention to provide an ultraviolet curable coating composition for use and an airbag formed with the film.

[0007]

The present inventor has conducted intensive studies to achieve the above object, and as a result, the following (A)
The coating composition obtained by blending the components (F) to (F) has an ultraviolet curability or an ultraviolet-condensation curability, and has a property of being cured in a short time by irradiating ultraviolet light. By coating the base fabric and curing it with ultraviolet light, it adheres uniformly and firmly to the base fabric surface in a short time, and has excellent tackiness and flame retardancy on the surface,
Therefore, they have found that the above composition is effective as a coating composition for an airbag, and have accomplished the present invention.

[0008] Ultraviolet curing type coating set for airbag
Product (A) an organopolysiloxane having at least two hydroxyl groups in one molecule, (B) a (meth) acryl-functional alkoxysilane represented by the following general formula (1), (C) a following general formula (2) (D) an alkoxy-α-silyl ester represented by the following general formula (3), (E) a curing catalyst, and (F) a sensitizer. Mold coating composition.

[0009]

Embedded image (Wherein, R ¹ represents a hydrogen atom or a methyl group, R ² represents a divalent organic group, R ³ and R ⁴ represent the same or different unsubstituted or substituted monovalent hydrocarbon groups, and a represents 0 , 1 or 2)

[0010]

Embedded image SnX ₂
… (2) And R ⁶ are each an unsubstituted or substituted monovalent hydrocarbon group. )

[0011]

Embedded image (Wherein, R ⁷ and R ⁸ each represent a methyl group or an ethyl group, R ⁹ , R ¹⁰ and R ¹¹ represent the same or different unsubstituted or substituted monovalent hydrocarbon groups, and b represents 0,1
Or 2. )

Now, the present invention will be described in further detail. The ultraviolet-curable coating composition for an airbag of the present invention comprises the above components (A) to (F).

Here, as the organopolysiloxane having at least two hydroxyl groups in one molecule of the component (A), known organopolysiloxanes can be used. For example, the following formula (4)
Can be mentioned.

[0014]

Embedded image

In the above formula (4), R and R ′ are the same or different, unsubstituted or substituted monovalent hydrocarbon groups,
Those having 1 to 8 carbon atoms are preferred. Examples of such a monovalent hydrocarbon group include alkyl groups such as methyl group, ethyl group and propyl group, alkenyl groups such as vinyl group and allyl group, aryl groups such as phenyl group and tolyl group, and cycloalkyl groups such as cyclohexyl group. A chloromethyl group, a trifluoropropyl group, in which a group or a part or all of the hydrogen atoms bonded to carbon atoms of these groups are substituted with a halogen atom, a cyano group, or the like;
And a cyanoethyl group. In the formula (4), c is an integer of 5 or more.

Component (A) of organopolysiloxane 2
The viscosity at 5 ° C. is preferably 25 to 500,000 cs, particularly preferably 1,000 to 100,000 cs. The organopolysiloxane is preferably one in which the molecular chain terminals are blocked with hydroxyl groups. Furthermore,
Examples of the organopolysiloxane include varnishes having a branched structure.

The (meth) acryl-functional alkoxysilane of the component (B) of the present invention is represented by the above formula (1). In this case, R ² has 1 to 8 carbon atoms, for example, an alkylene group, and R ³ and R ⁴ are the same as R and R ′ described above.

Examples of such a (meth) acryl-functional alkoxysilane include the following.

[0019]

Embedded image

The amount of the component (B) is 100 parts (A)
Parts (parts by weight, hereinafter the same) is preferably 0.1 to 10 parts, particularly preferably 1 to 5 parts. If the amount is less than 0.1 part, a sufficient rubber elastic body cannot be obtained after ultraviolet curing. If it is more than 10 parts, the cured rubber elastic body becomes brittle.

The divalent tin compound as the component (C) is represented by the above formula (2). In this case, R ⁵ and R ^{5
6 is the same} as R and R '.

The following are examples of such divalent tin compounds.

[0023]

Embedded image

The amount of component (C) is as follows:
The amount is preferably 0.05 to 5 parts, particularly 0.1 to 1 part, with respect to 00 parts. If the amount is less than 0.05 part, sufficient curability cannot be obtained. Therefore, there is a disadvantage that storage stability is deteriorated.

The alkoxy-α-silyl ester of the component (D) is as shown in the above formula (3). In the formula (3), R ⁹ , R ¹⁰ and R ¹¹ are the same as R and R ′. .

The following are examples of such alkoxy-α-silyl esters.

[0027]

Embedded image (Wherein Me is a methyl group, Et is an ethyl group, ⁿ Bu is n
-A butyl group. )

The amount of the component (D) is 100
The amount is preferably 1 to 10 parts, especially 1 to 5 parts, and if it is less than 1 part, sufficient storage stability cannot be exhibited, and if it is more than 10 parts, the curability will be poor.

The curing catalyst of the component (E) is for accelerating the condensation curing reaction between the components (A) and (B) in the presence of moisture. As such a curing catalyst,
For example, lead-2-ethyl octate, dibutyltin diacetate, dibutyltin dilaurate, butyltin tri-2-ethylhexoate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2 -Ethylhexoate, zinc-2-ethylhexoate, stannous caprylate, tin naphthenate, tin oleate, tin butylate, titanium naphthenate, zinc naphthenate, cobalt naphthenate, zinc stearate, etc. Metal salts of organic carboxylic acids, organic titanates such as tetrabutyl titanate, tetra-2-ethylhexyl titanate, triethanolamine titanate and tetra (isopropenyloxy) titanate; organic titanium compounds such as organosiloxytitanium and carbonyltitanium; alkoxy Aluminum compound, 3-aminopro Le triethoxysilane, N-
(Trimethoxysilylpropyl) amine compounds such as aminoalkyl-substituted alkoxysilanes such as ethylenediamine, hexylamine, dodecylamine phosphate and salts thereof,
Quaternary ammonium salts such as benzyltriethylammonium acetate, potassium acetate, sodium acetate, lower fatty acids of alkali metal salts such as lithium oxalate, dialkylhydroxyamines such as dimethylhydroxyamine and diethylhydroxyamine, tetramethylguanidine; The guanidyl compound represented and the guanidyl-containing silane or siloxane can be exemplified.

[0030]

Embedded image

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

The compounding amount of the curing catalyst (E) is as follows:
0.01 to 10 parts, especially 0.1 to 10 parts per 100 parts of the component
Preferably it is 5 parts. The amount of component (E) used is 0.
If it is less than 01 part, it takes a long time to cure, and if the film is thick, it may be difficult to cure uniformly to the deep part, and if it exceeds 10 parts, the time required for film formation becomes extremely short. Various inconveniences occur in the work surface, and the resulting cured film may have poor heat resistance and weather resistance in some cases.

Specific examples of the sensitizer of the component (F) include acetophenone, propiophenone, benzophenone, xanthol, fluorein, benzaldehyde, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, and 4-methylacetophenone. , 3-
Pentyl acetophenone, 4-methoxyacetophenone, 3-bromoacetophenone, 4-allylacetophenone, p-diacetylbenzene, 3-methoxybenzophenone, 4-methylbenzophenone, 4-chlorobenzophenone, 4,4-dimethoxybenzophenone, 4-chloro-4 -Benzylbenzophenone, 3-chloroxanthone, 3,9-dichloroxanthone, 3-chloro-
8-nonyl xanthone, benzoin, benzoin methyl ether, benzoin butyl ether, bis (4-dimethylaminophenol) ketone, benzyl methoxy ketal, 2-chlorothioxanthone and the like.

The compounding amount of the sensitizer of the component (F) is 0.01 to the siloxane amount contained in the coating composition, since the coating composition only needs to be slightly light-sensitized.
Although it can be 10% by weight, it is particularly preferably 0.05 to 5% by weight.

Since this composition contains a photopolymerizable acryloxyorganosilyl group, it cures in a short time of 1 to 20 seconds to become a rubber elastic body when irradiated with ultraviolet rays. The rubber elastic body has excellent heat resistance, weather resistance, and low temperature characteristics, which are characteristics of silicone rubber, and thus 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 for coating this 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 coating composition is formed on a base fabric for an airbag. The airbag substrate on which a 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.

[0042]

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 hydroxy groups and the viscosity was 5,000 c
p Polydimethylsiloxane (100 parts), fumed silica (10 parts), methacryloxypropyltrimethoxysilane (1.7 parts), tin dioctate (0.1 part), 2-ethylhexyl 2-trimethoxysilylpropionate (3 parts), diethoxyacetophenone (2) Parts, dibutyltin dilaurate 0.5
Was added and kneaded in a dry atmosphere to prepare a coating composition 1.

Comparative Example 1 The relative viscosity of a 25% by weight toluene solution consisting of 99.8% by mole of dimethylsiloxane unit and 0.2% by mole of methylvinylsiloxane unit and having a molecular chain terminal blocked by a dimethylvinylsiloxane group was determined. To 100 parts of 2.8 organopolysiloxane, 40 parts of hydrophobic silica having a specific surface area of 230 m ² / g treated with a trimethylsilyl group and 1.0 part of dimethylpolysiloxane diol having a molecular chain terminal blocked with a silanol group Was added and heat-treated at 180 ° C. for 2 hours in a kneader to prepare a compound.

Next, 3.5 parts of 2,4-dichlorobenzoyl peroxide, a 50% pure organic peroxide, was added to 100 parts of the 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₎ an isocyanate group-containing silane represented by 3 _NCO added 5 parts relative to solid content 100 parts of the above toluene solution,
Coating composition 2 was prepared.

The above coating composition 1 was prepared to have a linear density of 18
One side of a plain woven nylon fiber 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 above 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 then 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 sample at% RH for one week to swell each sample, the same adhesion test as above was performed to measure the adhesion after wetting. In FIG. 1, reference numeral 1 denotes a nylon fiber fabric, 2 denotes a cured silicone film, 3 denotes a stainless steel scratching device, and 4 denotes a weight for applying a load to the device 3.

Also, 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.

[0050]

[Table 1]

[0051]

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.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Miyoshi 1-10 Hitomi, Matsuida-cho, Usui-gun, Gunma Prefecture Inside the Silicone Electronics Materials Research Laboratory, Shin-Etsu Chemical Co., Ltd. (56) References JP-A-62-96562 ( JP, A) JP-A-5-25435 (JP, A) JP-A-60-110752 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09D 183/06 C08L 83/06 C08L 83/08

Claims (2)

(57) [Claims] (A) an organopolysiloxane having at least two hydroxyl groups in one molecule; (B) a (meth) acryl-functional alkoxysilane represented by the following general formula (1): (Wherein, R ¹ represents a hydrogen atom or a methyl group, R ² represents a divalent organic group, R ³ and R ⁴ represent the same or different unsubstituted or substituted monovalent hydrocarbon groups, and a represents 0 is 1 or 2.) (C) 2 divalent tin compound represented by the following general formula (2), ## STR2 ## SnX ₂
… (2) And R ⁶ are each an unsubstituted or substituted monovalent hydrocarbon group. ) (D) an alkoxy-α-silyl ester represented by the following general formula (3): (Wherein, R ⁷ and R ⁸ each represent a methyl group or an ethyl group, R ⁹ , R ¹⁰ and R ¹¹ each represent the same or different unsubstituted or substituted monovalent hydrocarbon group, and b represents 0,1
Or 2. An ultraviolet curable coating composition for an airbag, comprising (E) a curing catalyst and (F) a sensitizer. 2. An airbag obtained by forming a cured film of the coating composition for an airbag according to claim 1 on an airbag base fabric.