JP2571986C - - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coating composition for an air bag of a vehicle or the like. For details, see Airbags for Vehicles, etc., which have an adhesive strength that can withstand the impact of expansion, especially expansion at high temperatures.
The present invention relates to a coating composition for an egg . 2. Description of the Related Art In recent years, airbags have been put into practical use as safety devices for protecting occupants of automobiles. Such an airbag is generally composed of a base fabric in which chloroprene rubber is coated on a nylon fabric. However, it is difficult to reduce the weight of the base fabric coated with the chloroprene rubber, and in particular, there is a disadvantage that the physical properties deteriorate with the passage of time. Recently, an airbag base fabric coated with silicone rubber has been proposed (see JP-A-63-78744). This airbag base fabric coated with silicone rubber has the advantage of being excellent in high temperature properties,
Further, silicone rubber has an advantage that it can be reduced in weight because thin film coating is possible. However, this silicone rubber has a disadvantage that its adhesive strength to a synthetic fiber fabric for airbags such as nylon 66 is insufficient. That is, when the air bag is operated, there is a problem that the rubber layer is peeled off or burnt out due to high temperature gas generated from inside the inflator and intense rubbing of the coating surfaces during expansion. DISCLOSURE OF THE INVENTION The present inventors have studied to solve the above-mentioned problems, and as a result, dissolved a silicone rubber composition containing a specific organosilicon compound in an organic solvent. The present inventors have found that the resulting composition strongly adheres to the synthetic fiber woven fabric for airbags and has excellent thin film coating properties, and has accomplished the present invention. That is, an object of the present invention is to provide an airbag base fabric which exhibits excellent adhesive strength to a synthetic fiber woven fabric for an airbag, has excellent folding storage properties (flexibility) and extensibility, and has little deterioration due to aging. to provide a Eaba' grayed coating composition that can be obtained. Means for Solving the Problems and Action Therefor The object of the present invention is to provide (A) 100 parts by weight of an organopolysiloxane raw rubber containing two or more silicon-bonded alkenyl groups in one molecule; 5 to 100 parts by weight of powdery silica, (C) 0.1 to 20 parts by weight of an organosilicon compound having an epoxy group bonded to a silicon atom via an alkylene group, (D) platinum-based compound catalyst (A) component 100 0.1 to 500 parts by weight of a platinum-based metal , and (E) an organohydride containing at least two silicon-bonded hydrogen atoms per molecule,
Roger emissions polysiloxanylalkyl emissions silicon-bonded moles of hydrogen atoms and (A) the ratio of moles of alkenyl groups in component (0.6: 1) - (20: 1) and a silicone rubber composition comprising a quantity For airbags made by dissolving substances in organic solvents.
Can be achieved by the composition of the binding agent . [0005] The organopolysiloxane raw rubber of the component (A) used in the present invention is a component which is a main component of the composition of the present invention. Since the composition of the present invention becomes a silicone rubber coating film having rubber elasticity after curing. Must have two or more silicon-bonded alkenyl groups in one molecule. Such an organopolysiloxane has the general formula: [Wherein R is an alkyl group such as a methyl group, an ethyl group, or a propyl group; an alkenyl group such as a vinyl group or an allyl group; an aryl group such as a phenyl group; an alkyl halide such as a 3,3,3-tripropyl group; And a substituted or unsubstituted monovalent hydrocarbon group. n is 1.9 to 2.1. ] Is a substantially linear organopolysiloxane represented by the formula: Specific examples of the component include dimethylpolysiloxane having dimethylvinylsiloxy groups at both ends, dimethylsiloxane / methylvinylsiloxane copolymer having dimethylvinylsiloxy groups at both ends, and dimethylsiloxane / methylphenylsiloxane having dimethylvinylsiloxy groups at both ends. And copolymers. As the finely divided silica as the component (B) used in the present invention, those which have been conventionally used as a reinforcing filler for silicone rubber and which are well known can be used.
The type is not particularly limited. Such silicas include fumed silica,
Precipitated silica is exemplified. Among them, silica in the form of ultrafine powder having a particle size of 50 mμ or less and a specific surface area of 50 m ² / g or more is preferable. Further, surface-treated silica, for example, silica previously surface-treated with organosilane, organosilazane, diorganocyclopolysiloxane, etc., is more preferable. The component (C) used in the present invention is an organosilicon compound containing an epoxy group bonded to a silicon atom via an alkylene group, which is essential for improving the adhesiveness to a synthetic fiber fabric for airbag coating. Component is organoalkoxysilane containing epoxy group such as γ-glycidoxypropyltrimethoxysilane, 3,4-epoxycyclohexylethyltrimethoxysilane; epoxy group-containing organopolysiloxane having vinyl group and alkoxy group, silicon atom bond Epoxy group-containing organopolysiloxanes such as an epoxy group-containing organopolysiloxane having a hydrogen atom and an epoxy group-containing organopolysiloxane having a silicon-bonded hydrogen atom and an alkoxy group are exemplified. Among them, specific examples of the epoxy group-containing organopolysiloxane include the following compounds. Embedded image Embedded image Embedded image Embedded image The platinum compound catalyst of the component (D) used in the present invention cures the composition of the present invention.
It is a catalyst for Examples of the platinum compound catalyst include platinum fine powder, platinum black, chloroplatinic acid, platinum tetrachloride, olefin complex of chloroplatinic acid, complex of chloroplatinic acid with methylvinylsiloxane, rhodium compound and palladium compound. Is exemplified. The amount of the platinum-based compound catalyst is usually 0.1 parts by weight of platinum-based metal per 1 million parts by weight of the component (A).
It is used in the range of ５００500 parts by weight. [0010] An organo containing at least two silicon-bonded hydrogen atoms in one molecule of the component (E).
Nohydrogenpolysiloxane is a cross-linking agent, and is a platinum-based compound of component (D).
The composition of the present invention is cured by reacting with the component (A) in the presence of a catalyst . Examples of the component (E) include a methylhydrogenpolysiloxane having trimethylsiloxy groups at both ends, a dimethylsiloxane / methylhydrogensiloxane copolymer having trimethylsiloxy at both ends, and a methylphenylsiloxane / methylhydrogen having both ends of dimethylphenylsiloxy group. Examples thereof include siloxane copolymers, cyclic methyl hydrogen polysiloxanes, and copolymers composed of dimethyl hydrogen siloxy units and SiO _4/2 units. The ratio of the number of moles of silicon-bonded hydrogen atoms in the organohydrogenpolysiloxane to the number of moles of silicon-bonded alkenyl groups in the component (A) is (0.6: 1) to (20: 1) as the amount to be. The composition of the present invention comprises the above components (A) to (E) . In addition to the above components (A) to (E) , an organopolysiloxane resin as component (F) Is preferably blended. Having a high strength of the silicone rubber coating film will be obtained. Such organopolysiloxane resins include:
For example, a resin composed of (CH ₃ ) ₃ SiO _1/2 units and SiO _4/2 units, (CH ₃ ) ₃
Resin consisting of SiO _1/2 unit and (CH ₂ CH) SiO _3/2 unit and SiO _4/2 unit, from (CH ₂ ＣＨCH) (CH ₃ ) ₂ SiO _1/2 unit and SiO _4/2 unit Become resin,
(CH ₂ ＣＨCH) (CH ₃ ) ₂ SiO _1/2 unit and (CH ₂ ＣＨCH) SiO _3/2 unit and S
Resins consisting of iO _4/2 units are included. Among these, resins containing a vinyl group are preferred. In order to produce the composition of the present invention, for example, the components (A) and (B) or the components (A), (B) and (F) are preliminarily added to a two-roll mill, a kneader mixer, and a pressurizer. After uniformly kneading with a mixer such as a kneader mixer or a loss mixer to prepare a silicone rubber base, the components (C), (D) and (E) are preferably added and blended. [0013] The composition of the present invention is made of synthetic fiber fabrics for airbags (eg, polyamide fiber fabrics such as nylon 6, nylon 66, nylon 46, etc., aramid fiber fabrics, polyester fiber fabrics represented by polyalkylene terephthalate, polyetherimide fibers). Woven fabric, sulfone fiber woven fabric, carbon fiber woven fabric, etc.) and then cured to obtain a silicone rubber coated airbag base fabric. In applying the composition of the present invention to a synthetic fiber fabric for an airbag, the most preferred airbag fabric is a nylon 66 fiber fabric. When coating an organopolysiloxane composition on a synthetic fiber woven fabric for an airbag, the composition of the present invention contains an organic solvent such as xylene or toluene, and may be adjusted to a viscosity that facilitates application. The composition of the present invention contains various additives conventionally known as additives for silicone rubber, for example, inorganic fillers such as titanium oxide, carbon black, red iron oxide, rare earth oxides, cerium silanolate, and pigments. The addition and blending of a heat-resistant agent and the like may be carried out as long as the object of the present invention is not impaired. The above-mentioned components (A) to (E) or the components (A) to (F) may contain an organic solvent if necessary. After adding pigments, heat-resistant agents, etc., and mixing them uniformly, it is coated on a synthetic fiber fabric for airbags, placed in a hot-air drying oven and heated and cured to form a silicone rubber-coated base fabric for airbags. . The composition of the present invention as described above,
The hardness (JIS A) of the silicone rubber after heat curing is preferably in the range of 30 to 60. When this is applied to a synthetic fiber fabric for an air bag, the silicone rubber coating film and the synthetic fiber fabric for the air bag are firmly bonded and integrated. The adhesive strength is 1 kgf / cm or more, and the silicone rubber coating film does not peel off due to severe rubbing during operation of the air bag. Next, the present invention will be described by way of examples. In the examples, “parts” means “parts by weight”, the viscosity is a value at 25 ° C., and C st represents centistokes. Me represents a methyl group, and Vi represents a vinyl group. Example 1 99.85 mol% of dimethylsiloxane units and 0.1 of methylvinylsiloxane units
100 parts of 5 mol% of dimethylsiloxane / methylvinylsiloxane copolymer raw rubber having both ends of trimethylsiloxy groups blocked (degree of polymerization 3000), 7.0 parts of dimethylpolysiloxane having both ends of silanol groups and having a viscosity of 60 cst at 25 ° C. And 30 parts of fumed silica having a specific surface area of 200 m ² / g were charged into a kneader mixer, and kneaded under heating until uniform, to prepare a rubber base. 30 parts of this rubber base was dissolved in 70 parts of toluene while stirring at room temperature. Subsequently, 1.0 part of methylhydrogenpolysiloxane having an average molecular formula of Me ₃ SiO (MeHSiO) ₆ (Me ₂ SiO) ₄ SiMe ₃ was added to 100 parts of the dispersion solution, chloroplatinic acid and divinyltetramethyldimethyl 0.5 part of a complex with siloxane (0.4% by weight of platinum) and 0.4 part of 3,5-dimethyl-1-hexyn-3-ol as a curing inhibitor were added and mixed uniformly. The viscosity of this dispersion solution was 50,000 cst. Furthermore, the following adhesion-imparting agents were added to this dispersion solution to prepare coating compositions for airbags. Next, this was coated on a nylon 66 (420 denier) fabric for an air bag, and the adhesive strength was measured. Here, the coating method on the nylon 66 fabric for an air bag is such that the coating amount of the silicone rubber composition is 50 to 60 g / m ² with a coater and air-dried in an oven at 120 ° C. for 4 minutes. The resin was cured by heating at 180 ° C. for 5 minutes to prepare an airbag-coated base fabric. Two coated surfaces of the airbag-coated base fabric are superimposed, and a gap between the two is adhered with a room-temperature-curable silicone rubber adhesive [trade name “SE9145 RTV” manufactured by Dow Corning Toray Silicone Co., Ltd.]. After curing for one day, the test piece was cut into a piece having a width of 2.5 cm and a length of 10 cm and subjected to a peel test to measure the adhesive strength at that time. In the air bag inflation test, hot air at a temperature of 170 to 180 ° C. is blown into the air bag under the condition of a pressure of 7 to 8 kg / cm ² to instantaneously inflate the air bag and visually check whether or not the silicone rubber coating film has peeled off. Observation was performed. Table 1 shows the evaluation results. Adhesion-imparting agent (a) γ-glycidoxypropyltrimethoxysilane Adhesion-imparting agent (b) Adhesion imparting agent (c) Adhesion-imparting agent (d) 50 parts of γ-glycidoxypropyltrimethoxysilane and an average unit formula are as follows: A mixture of 50 parts of a siloxane oligomer represented by the formula: [Table 1] Example 2 The coating composition for an air bag obtained in Example 1 was coated on a polyester fiber woven fabric (420 denier) for an air bag in the same manner as in Example 1. The characteristics were measured. Table 2 shows the results of these evaluations. [Table 2] EFFECT OF THE INVENTION The coating composition for an air bag of the present invention comprises the components (A) to (E) , and particularly binds to a silicon atom via the alkylene group of the component (C). Since it contains an organosilicon compound containing an epoxy group, it exhibits excellent adhesive strength to a synthetic fiber fabric for an air bag made of a synthetic fiber fabric such as nylon 66, and expands with a high-temperature gas generated from inside the inflator. The silicone rubber coating film is not peeled off or burned out due to intense friction between the coated surfaces.

Claims (1)

Claims: (A) 100 parts by weight of an organopolysiloxane raw rubber containing two or more silicon-bonded alkenyl groups in one molecule, (B) 5 to 100 parts by weight of finely divided silica (C) 0.1 to 20 parts by weight of an organosilicon compound containing an epoxy group bonded to a silicon atom via an alkylene group, (D) platinum-based compound catalyst (A) 1,000,000 parts by weight of platinum 0.1 to 500 parts by weight of a system metal and (E) an organohydride containing at least two silicon-bonded hydrogen atoms in one molecule
Roger emissions polysiloxane silicon-bonded moles of hydrogen atoms and is (A) the ratio of moles of alkenyl groups in component (0.6: 1) - (20: 1) and a consisting amount silicone rubber composition Air bag coating dissolved in organic solvent
Ting agent composition . 2. The air according to claim 1, wherein the organosilicon compound as the component (C) is an organosilicon compound containing an epoxy group bonded to a silicon atom via an alkylene group and an alkoxy group bonded directly to the silicon atom. Coating composition for bags . 3. The airbag cushion according to claim 1, wherein the silicone rubber coating film has an adhesive force of at least 1.0 kgf / cm to the synthetic fiber fabric for airbag.
A coating agent composition .