WO2019208021A1 - Addition curing liquid silicone rubber composition for airbag, and airbag - Google Patents

Abstract

Provided are an addition curing liquid silicone rubber composition for an airbag, and an airbag. The addition curing liquid silicone rubber composition for an airbag contains: (A) organopolysiloxane containing two or more silicon-bonded alkenyl groups and having a polymerization degree of 100 to 2000: 100 parts by mass; (B) organohydrogenpolysiloxane containing two or more SiH groups: an amount such that the SiH groups in the component is 1 to 10 moles per one mole of a total of silicon-bonded alkenyl groups in the (A) component and (D) component; (C) a silica fine powder with a specific surface area of not less than 50 m2/g: 1 to 50 parts by mass; (D) a surface treatment agent containing a silicon-bonded alkenyl group: 0.01 to 5 parts by mass with respect to 100 parts by mass of the (C) component; (E) a hydrosilylation reacting catalyst: 1 to 500 ppm by mass of a catalyst metal element with respect to a total mass of (A) to (D); and (F) an organic silicon compound containing adhesion-imparting function group: 0.1 to 10 parts by mass.

Description

Addition-curing type liquid silicone rubber composition for air bag and air bag

The present invention relates to an addition-curable liquid silicone rubber composition for an air bag suitable for producing an air bag and an air bag.

Conventionally, silicone rubber compositions for air bags have been proposed for the purpose of forming a rubber coating on the fiber surface. Since an air bag having a silicone rubber coating is excellent in airtightness and low combustion rate, it is suitably used as an air bag for automobiles and the like.

As such a silicone rubber composition for an air bag, an addition curable liquid silicone rubber composition (specialized in that the coating material is excellent in coating property by making the composition have an appropriate thixo ratio. JP 2008-074881 gazette: Patent Document 1) and a resin-like polysiloxane, and a siloxane component is preliminarily mixed with silica, a surface treatment agent, and water, so that it is an addition-curing liquid that is excellent in low combustion rate. By coating a base fabric with a silicone rubber composition (Japanese Patent Laid-Open No. 2013-209517: Patent Document 2) and an addition-curable silicone rubber composition based on a branched-chain organopolysiloxane containing Q units. A method of manufacturing an air bag having excellent airtightness (Japanese Patent Publication No. 2013-516521: Patent Document 3) is disclosed. To have.

However, curtain airbags that are housed along the roof side from the front pillar and are required to maintain a constant inflation time in order to protect the head and prevent popping out in the event of a collision or vehicle overturn have recently been Air bags manufactured by coating these compositions on the base fabric are required to reduce the weight and size of the air-conditioner. Was not enough to satisfy.

JP 2008-074881 A JP 2013-209517 A Special table 2013-516521 gazette

The present invention has been made in view of the above circumstances, and is an addition-curable liquid silicone rubber composition for an air bag that suppresses leakage of an inflator gas when the air bag is deployed and has excellent inflating time, and an air bag. The purpose is to provide.

As a result of intensive studies to achieve the above object, the present inventors have found that the liquid silicone rubber composition containing the components (A) to (F) described later as essential components, particularly the silicon atom of the component (D). By adding a surface treatment agent containing a bonded alkenyl group, which is a surface treatment of silica fine powder having a BET specific surface area of (C) component of 50 m ² / g or more, this liquid silicone rubber composition is air-treated. It is found that an air bag obtained by applying a predetermined amount to the surface of the base fabric for the bag and heat-curing it suppresses leakage of the inflator gas when the air bag is deployed, and has excellent inflating time, It came to make this invention.

（式中、Ｒ¹は独立して炭素数１～１２の１価飽和脂肪族炭化水素基又は炭素数６～１２の１価芳香族炭化水素基であり、Ｒ²は独立して水素原子又は炭素数１～６のアルキル基であり、ｎは０～５０の整数、ｍは１～５０の整数であり、式（２）において、各シロキサン単位の配列はブロックであってもランダムであってもよい。）
３.（Ｆ）成分が、アルケニル基及び／又はＳｉＨ基を含む場合、組成物中の（Ａ）成分、（Ｄ）成分、及び（Ｆ）成分中に含まれるケイ素原子結合アルケニル基の合計１モル当たり、（Ｂ）成分及び（Ｆ）成分中に含まれるＳｉＨ基の合計量が１～１０モルとなる量が配合されてなる上記１に記載のエアーバッグ用付加硬化型液状シリコーンゴム組成物。
４．更に、（Ｇ）成分として、有機チタニウム化合物、有機ジルコニウム化合物、及び有機アルミニウム化合物から選ばれる少なくとも１種の縮合触媒を、（Ａ）成分１００質量部に対して、０．１～５質量部含有することを特徴とする上記１～３のいずれかに記載のエアーバッグ用付加硬化型液状シリコーンゴム組成物。
５．エアーバッグ用基布上に、上記１～４のいずれかに記載のエアーバッグ用付加硬化型液状シリコーンゴム組成物の硬化被膜を有することを特徴とするエアーバッグ。 Accordingly, the present invention provides the following addition-curable liquid silicone rubber composition and airbag for an airbag.
1. (A) Organopolysiloxane having a degree of polymerization of 100 to 2,000 containing alkenyl groups bonded to two or more silicon atoms in one molecule: 100 parts by mass
(B) Organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to at least two silicon atoms in one molecule: SiH groups contained in this component are the component (A) and the following (D) An amount of 1 to 10 moles per mole of silicon atom-bonded alkenyl groups contained in the component;
(C) Silica fine powder having a BET specific surface area of 50 m ² / g or more: 1 to 50 parts by mass,
(D) Surface treatment agent containing alkenyl group bonded to silicon atom (excluding component (A)): 0.01 to 5 parts by mass with respect to 100 parts by mass of silica fine powder of component (C) ,
(E) Catalyst for hydrosilylation reaction: 1 to 500 ppm in terms of the mass of the catalytic metal element with respect to the total mass of (A) to (D),
(F) Organosilicon compound containing an adhesion-imparting functional group (excluding components (A), (B), and (D)): characterized by having 0.1 to 10 parts by mass as an essential component Addition-curing liquid silicone rubber composition for airbags.
2. 2. The component (D) as described in 1 above, wherein the component is selected from chlorosilanes having at least one vinyl group in one molecule, silazanes, and organosilicon compounds represented by the following formula (1) or (2): Addition-curing liquid silicone rubber composition for air bags.

(Wherein R ¹ is independently a monovalent saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² is independently a hydrogen atom or An alkyl group having 1 to 6 carbon atoms, n is an integer of 0 to 50, m is an integer of 1 to 50, and in the formula (2), the arrangement of each siloxane unit is random even if it is a block. May be good.)
3. When the component (F) contains an alkenyl group and / or SiH group, a total of 1 of the silicon-bonded alkenyl groups contained in the component (A), the component (D), and the component (F) in the composition 2. The addition curable liquid silicone rubber composition for an air bag as described in 1 above, wherein the total amount of SiH groups contained in the component (B) and the component (F) is 1 to 10 moles per mole. .
4). Further, as component (G), at least one condensation catalyst selected from organic titanium compounds, organic zirconium compounds, and organoaluminum compounds is contained in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of component (A). 4. The addition-curable liquid silicone rubber composition for an air bag as described in any one of 1 to 3 above.
5. An air bag comprising a cured coating of the addition-curable liquid silicone rubber composition for an air bag according to any one of 1 to 4 above on a base fabric for an air bag.

According to the present invention, the leakage of the inflator gas is suppressed when the air bag is deployed, and the addition curable liquid silicone rubber composition for an air bag excellent in sustainability of the inflating time, and the base cloth is coated and cured. Thus, an air bag having excellent mechanical strength can be obtained.

Hereinafter, the present invention will be described in more detail. In the present specification, the viscosity is a value measured with a rotational viscometer at 25 ° C. by the method described in JIS K 7117-1: 1999. The degree of polymerization is a value obtained as a weight average degree of polymerization (weight average molecular weight) in terms of polystyrene in GPC (gel permeation chromatography) analysis using toluene as a developing solvent.

<Addition-curable liquid silicone rubber composition>
The addition-curable liquid silicone rubber composition for an air bag of the present invention contains the following components (A) to (F) and is liquid at room temperature (25 ° C.). Hereinafter, each component will be described in detail.

[(A) component]
The organopolysiloxane of component (A) is an organopolysiloxane that is liquid at 25 ° C. containing two or more alkenyl groups bonded to silicon atoms in one molecule, and is a base polymer (main agent) of the composition according to the present invention. It is.

Examples of the molecular structure of the component (A) include linear, cyclic, and branched chains. The main chain basically consists of repeating diorganosiloxane units, and both ends of the molecular chain are triorganosiloxy. Linear diorganopolysiloxanes blocked with groups are preferred. In addition, when the molecular structure of the organopolysiloxane of component (A) is linear or branched, the position of the silicon atom to which the alkenyl group is bonded in the organopolysiloxane molecule is at the end of the molecular chain (ie, Either a triorganosiloxy group) and a molecular chain (that is, a difunctional diorganosiloxane unit or a trifunctional monoorganosilsesquioxane unit located at the non-terminal end of the molecular chain) may be used. Particularly preferred as the component (A) is a linear diorganopolysiloxane containing alkenyl groups bonded to silicon atoms at both ends of the molecular chain.

Examples of the alkenyl group bonded to the silicon atom in the component (A) usually include those having 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples thereof include a vinyl group, an allyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a cyclohexenyl group, a heptenyl group, and the like, and a vinyl group is particularly preferable.

The content of the alkenyl group bonded to the silicon atom in the component (A) is 0.001 with respect to the entire monovalent organic group bonded to the silicon atom (that is, unsubstituted or substituted monovalent hydrocarbon group). It is preferably about 10 to 10 mol%, particularly preferably about 0.01 to 5 mol%.

Examples of the monovalent organic group bonded to the silicon atom other than the alkenyl group as component (A) include, for example, the same or different unsubstituted or substituted, usually 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms. Of these monovalent hydrocarbon groups. Specific examples of the monovalent organic group include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, cyclohexyl group, heptyl group and other alkyl groups; phenyl group, tolyl group, xylyl group, naphthyl group Aryl groups such as benzyl group, phenethyl group, and the like; halogen-substituted alkyl groups such as chloromethyl group, 3-chloropropyl group, 3,3,3-trifluoropropyl group, etc., particularly methyl group And a phenyl group.

The polymerization degree of the component (A) is 100 to 2,000, more preferably 150 to 1,500. When the degree of polymerization is lower than 100, the mechanical properties of the resulting silicone rubber may be deteriorated. When the degree of polymerization is higher than 2,000, the viscosity of the resulting silicone rubber composition is increased and the coating workability is increased. May get worse.

Specific examples of the organopolysiloxane of component (A) include: a trimethylsiloxy group-capped dimethylsiloxane / methylvinylsiloxane copolymer with both ends of a molecular chain, a trimethylsiloxy group-capped methylvinylpolysiloxane with a molecular chain at both ends, and a trimethylsiloxy group-capped with both ends Siloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, dimethylvinylsiloxy group-blocked dimethylpolysiloxane at both ends of the molecular chain, dimethylvinylsiloxy group-blocked methylvinylpolysiloxane at both ends of the molecular chain, dimethylvinyl at both ends of the molecular chain Siloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, dimethylvinylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane / methylphenylsiloxane copolymer, molecular chain Terminal divinylmethylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends divinylmethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, molecular chain both ends trivinylsiloxy group-blocked dimethylpolysiloxane, molecular chain both ends trivinylsiloxy group Examples thereof include a blocked dimethylsiloxane / methylvinylsiloxane copolymer and a mixture of two or more of these organopolysiloxanes.
The (A) component organopolysiloxane may be used alone or in combination of two or more.

[Component (B)]
The (B) component organohydrogenpolysiloxane mainly acts as a crosslinking agent (curing agent) by hydrosilylation addition reaction with the alkenyl group in the (A) component.
Examples of the molecular structure of the component (B) include linear, cyclic, branched, and three-dimensional network (resin-like) structures, and at least two, preferably three, per molecule. It is necessary to have hydrogen atoms (SiH groups) bonded to at least silicon atoms, and it is desirable to have usually 2 to 300, preferably 3 to 200, more preferably 4 to 100 SiH groups. A liquid is used at 0 ° C. Such SiH groups may be located either at the end of the molecular chain or in the middle of the molecular chain, or may be located at both.

As this organohydrogenpolysiloxane, those represented by the following average composition formula (3) can be used.

In the formula (3), R ³ is the same or different from each other, and excludes an aliphatic unsaturated bond such as an alkenyl group, preferably an unsubstituted or substituted monovalent hydrocarbon bonded to a silicon atom having 1 to 10 carbon atoms. Groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, decyl, etc. An alkyl group, a phenyl group, a tolyl group, an xylyl group, an aryl group such as a naphthyl group, an aralkyl group such as a benzyl group, a phenylethyl group, a phenylpropyl group, or a part or all of the hydrogen atoms of these groups, Substituted by halogen atoms such as bromine and chlorine, for example, chloromethyl group, chloropropyl group, bromoethyl group, trifluoropropyl group And the like. R ³ is preferably an alkyl group or an aryl group, more preferably a methyl group or a phenyl group. A is 0.7 to 2.1, b is 0.001 to 1.0, and a + b is a positive number satisfying 0.8 to 3.0, preferably a is 1.0 to 2 0.0 and b are positive numbers satisfying 0.01 to 1.0 and a + b satisfying 1.5 to 2.5.

Examples of the organohydrogenpolysiloxane of component (B) include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, and tris (hydrogendimethylsiloxy). Methylsilane, tris (hydrogendimethylsiloxy) phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane / dimethylsiloxane cyclic copolymer, trimethylsiloxy group-blocked methylhydrogenpolysiloxane, trimethyl at both molecular chains Siloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer, trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane / methylphenylsiloxane copolymer at both ends of the molecular chain Molecular chain both ends trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane / diphenylsiloxane copolymer, molecular chain both ends dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane, molecular chain both ends dimethylhydrogensiloxy group-blocked dimethylpoly Siloxane, dimethylhydrogensiloxy group-capped dimethylsiloxane / methylhydrogensiloxane copolymer, both ends of the molecular chain dimethylhydrogensiloxy group-capped dimethylsiloxane / methylphenylsiloxane copolymer, dimethylhydrogen, both ends of the molecular chain Siloxy group-blocked dimethylsiloxane / diphenylsiloxane copolymer, molecular chain both ends dimethylhydrogensiloxy group-blocked methylphenylpolysiloxane, molecule And both ends endcapped with dimethyl hydrogen siloxy group diphenyl polysiloxane, in each of these exemplified compounds, those in which a part of the methyl group or entirely substituted with other alkyl groups such as ethyl group, a propyl group, the formula: R ⁴ ₃ Organosiloxane copolymer comprising a siloxane unit represented by SiO _0.5 and a siloxane unit represented by the formula: R ⁴ ₂ HSiO _0.5 and a siloxane unit represented by the formula: SiO ₂ , a siloxane unit represented by the formula: R ⁴ ₂ HSiO _0.5 And an organosiloxane copolymer composed of a siloxane unit represented by SiO ₂ , a siloxane unit represented by formula: R ⁴ HSiO and a siloxane unit represented by formula: R ⁴ SiO _1.5 or a siloxane unit represented by formula: HSiO _1.5 An organosiloxane copolymer comprising two or more of these organopolysiloxanes A mixture consisting of the above is mentioned. R ⁴ in the above formula is a monovalent hydrocarbon group other than an alkenyl group, and the same groups as R ³ are exemplified.

(B) The compounding quantity of a component is SiH contained in (B) component with respect to a total of 1 mol (or piece) of the silicon atom bond alkenyl group contained in (A) component and (D) component mentioned later. The amount of the group is 1 to 10 mol (or individual), preferably 1.2 to 9 mol (or individual), more preferably 1.5 to 8 mol (or individual).
When the SiH group contained in the component (B) is less than 1 mole relative to 1 mole in total of the silicon atom-bonded alkenyl groups contained in the component (A) and the component (D), the composition is sufficiently cured. In addition, when this exceeds 10 mol, the heat resistance of the obtained cured silicone rubber may be extremely inferior.
The (B) component organohydrogenpolysiloxane may be used alone or in combination of two or more.

[Component (C)]
The silica fine powder of component (C) acts as a reinforcing filler. In other words, it gives strength to the cured silicone rubber obtained from the composition according to the present invention. By using silica fine powder as a reinforcing filler, a coating film satisfying the strength required for the present invention is formed. It becomes possible to do. The silica fine powder has a specific surface area (BET method) of 50 m ² / g or more, preferably 50 to 400 m ² / g, more preferably 100 to 300 m ² / g, If it is less than 50 m ² / g, satisfactory strength characteristics cannot be imparted.

Such a silica fine powder may be a known silica powder conventionally used as a reinforcing filler for silicone rubber, provided that the specific surface area is within the above range. For example, fumed silica (fumed silica) Silica), precipitated silica (wet silica), and the like.

The reinforcing silica fine powder is, for example, a silica fine powder whose surface is hydrophobized with a surface treatment agent such as a (usually hydrolyzable) organosilicon compound such as chlorosilane, alkoxysilane, or organosilazane. Can do. In that case, these silica fine powders may be used in the form of a powder that has been subjected to surface hydrophobization treatment directly with a surface treatment agent, or silicone oil (for example, the alkenyl group of component (A) above). A surface treatment agent may be added at the time of kneading with (containing organopolysiloxane), and the surface may be hydrophobized.
In addition, the surface treatment agent used here is clearly distinguished in that it does not have an alkenyl group as compared with a surface treatment agent containing an alkenyl group bonded to a silicon atom of component (D) described later. Is done.

As a normal treatment method for the component (C), the surface treatment can be performed by a known technique. For example, the untreated silica fine powder and the surface treatment agent are added to a mechanical kneading apparatus or a fluidized bed sealed at normal pressure. If necessary, the mixture can be mixed at room temperature (25 ° C.) or heat treatment (heating) in the presence of an inert gas. In some cases, the surface treatment may be accelerated using water or a catalyst (hydrolysis accelerator or the like). The surface-treated silica fine powder can be produced by drying after kneading. The compounding quantity of a surface treating agent should just be more than the quantity calculated from the coating area of the surface treating agent.

Specific examples of the surface treatment agent include silazanes such as hexamethyldisilazane, 1,1,3,3,5,5-hexamethylcyclotrisilazane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrisilane. Silane couplings such as methoxysilane, butyltrimethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, trimethylmethoxysilane, triethylmethoxysilane, trimethylchlorosilane, dimethyldichlorosilane, chloropropyltrimethoxysilane, trimethylsilanol and hydroxypentamethyldisiloxane And organic silicon compounds such as polymethylsiloxane, organohydrogenpolysiloxane, etc., and hydrophobic silica fine powder surface-treated with these compounds can be used. As the surface treatment agent, silane coupling agents or silazanes are particularly preferable.

The amount of component (C) is 1 to 50 parts by weight, preferably 10 to 30 parts by weight, based on 100 parts by weight of the organopolysiloxane of component (A). If the blending amount is too small, the strength required for the present invention cannot be obtained. If the blending amount is too large, the viscosity of the composition becomes high, the fluidity is lowered, and the coating operation may be deteriorated.
(C) The fine powder silica of a component may be used individually by 1 type, or may use 2 or more types together.

[(D) component]
(D) The surface treating agent containing the alkenyl group couple | bonded with the silicon atom of a component acts as a strength improvement agent of the hardened | cured material of a silicone rubber composition.

（式中、Ｒ¹は独立して炭素数１～１２の１価飽和脂肪族炭化水素基又は炭素数６～１２の１価芳香族炭化水素基であり、Ｒ²は独立して水素原子又は炭素数１～６のアルキル基であり、ｎは０～５０の整数、ｍは１～５０の整数であり、式（２）において、各シロキサン単位の配列はブロックであってもランダムであってもよい。） Examples of the component (D) include those selected from chlorosilanes having at least one vinyl group in one molecule, silazanes, and organosilicon compounds represented by the following formula (1) or (2).

(Wherein R ¹ is independently a monovalent saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² is independently a hydrogen atom or An alkyl group having 1 to 6 carbon atoms, n is an integer of 0 to 50, m is an integer of 1 to 50, and in the formula (2), the arrangement of each siloxane unit is random even if it is a block. May be good.)

Specific examples of chlorosilanes having one or more vinyl groups in one molecule include dimethylvinylchlorosilane, methylvinyldichlorosilane, vinyltrichlorosilane, divinyldichlorosilane, methylphenylvinylchlorosilane, and the like. Specific examples of silazanes having one or more vinyl groups include 1,3-divinyl-1,1,3,3-tetramethyldisilazane, 1,1,3,3-tetravinyl-1,3-dimethyl. And disilazan, 1-vinyl-1,1,3,3,3-pentamethyldisilazane, 1,1,1,3,5,5,5-heptamethyl-3-vinyltrisilazane, etc. 1,3-divinyl-1,1,3,3-tetramethyldisilazane is preferred.

In the formula (1) or (2), specific examples of R ¹ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, octyl, decyl, etc. An alkyl group, an aryl group such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group, a cycloalkyl group such as a cyclohexyl group, an aralkyl group such as a benzyl group and a phenylethyl group, and the like, among which a methyl group is preferable.

In the formula (1) or (2), specific examples of R ² include a hydrogen atom or an alkyl such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, and a hexyl group. Among them, a hydrogen atom or a methyl group is preferable.

In the formula (1) or (2), n is an integer of 0 to 50, preferably an integer of 0 to 20. In the formula (2), m is an integer of 1 to 50, preferably an integer of 1 to 10.

In the present invention, the surface treatment agent containing an alkenyl group bonded to the silicon atom of the component (D) is mixed with the silica fine powder of the component (C) and heat-treated at 60 to 200 ° C. Since the surface treatment agent of component (D) is sufficiently supplied and treated on the surface of the silica fine powder, the cured product of the obtained silicone rubber composition can obtain the strength required for the present invention. In that case, as described above, for example, the silica fine powder of the component (C) may be previously mixed with the surface treatment agent of the component (D) in a powder state and heat-treated, When the silica fine powder of component (C) and silicone oil (for example, the alkenyl group-containing organopolysiloxane of component (A) above) are mixed, a surface treatment agent of component (D) is added so that the heat treatment is performed. May be.

Examples of the method for performing the surface treatment of the silica fine powder of the component (C) with the surface treatment agent of the component (D) in silicone oil include, for example, a part of the component (A), the component (C), and the component (D). All of these can be mixed at a temperature of less than 60 ° C. and then heat-treated at 60 to 200 ° C. for surface treatment. At that time, surface treatment agents such as chlorosilanes and silazanes which do not contain a vinyl group may be mixed at the same time. Moreover, you may accelerate | stimulate surface treatment using water or a catalyst (hydrolysis promoter etc.) depending on the case.

(C) The silica fine powder of component is mixed with the surface treatment agent of component (D) in a powder state in advance, and the heat treatment is performed by, for example, a mechanical kneading apparatus or fluidized bed sealed at normal pressure. The silica fine powder of component (C) and the surface treatment agent of component (D) are added, mixed in the presence of an inert gas as necessary, at a temperature of less than 60 ° C., and then heated at 60 to 200 ° C. By doing so, surface treatment can be performed. At that time, surface treatment agents such as chlorosilanes and silazanes which do not contain a vinyl group may be mixed at the same time. Moreover, you may accelerate | stimulate surface treatment using water or a catalyst (hydrolysis promoter etc.) depending on the case.

Component (D) is blended in an amount of 0.01 to 5 parts by weight, preferably 0.05 to 4.5 parts by weight, more preferably 0.10 based on 100 parts by weight of silica fine powder of component (C). Is 4 parts by mass. When the blending amount of the component (D) is less than 0.01 parts by mass, a sufficient reinforcing effect may not be obtained, and when it is more than 5 parts by mass, the hardness of the cured product becomes extremely high. The mechanical properties may be extremely deteriorated.
(D) A component may be used individually by 1 type, or may use 2 or more types together.

[(E) component]
The catalyst for hydrosilylation reaction of component (E) mainly promotes the addition reaction between the alkenyl group bonded to the silicon atom in component (A) and the SiH group in component (B). The catalyst for hydrosilylation reaction is not particularly limited. For example, platinum group metals such as platinum, palladium, rhodium; chloroplatinic acid; alcohol-modified chloroplatinic acid; chloroplatinic acid and olefins, vinylsiloxane or acetylene compound A coordination group compound: platinum group metal compounds such as tetrakis (triphenylphosphine) palladium, chlorotris (triphenylphosphine) rhodium, and the like, preferably a platinum group metal compound.

The amount of the component (E) may be an effective amount as a catalyst, but is preferably 1 to 500 ppm in terms of the mass of the catalytic metal element with respect to the total amount of the components (A) to (D). 10 to 100 ppm is preferred. If the amount is too small, the addition reaction may be remarkably slow or the composition may not be cured. If the amount is too large, the heat resistance of the cured product may be reduced.
(E) The addition reaction catalyst of a component may be used individually by 1 type, or may use 2 or more types together.

[(F) component]
Component (F) is an organosilicon compound containing an adhesion-imparting functional group. Examples of the adhesion-imparting functional group include an epoxy group, a silicon atom-bonded alkoxy group (alkoxysilyl group), a hydrosilyl group, an isocyanate group, and an acrylic group. And a methacryl group, and is added to develop and improve the adhesion of the silicone rubber composition to the air bag base fabric.
As the organosilicon compound, any organosilicon compound can be used as long as it has such an adhesion-imparting functional group, but an organic compound having at least one epoxy group and one silicon-bonded alkoxy group in each molecule. It is preferably a silicon compound, and has at least one epoxy group and at least one silicon atom-bonded alkoxy group (for example, trialkoxysilyl group, organodialkoxysilyl group, etc.) from the viewpoint of adhesion development. An organosilicon compound, for example, an organosilane, or a cyclic or linear organosiloxane having 2 to 100, preferably 4 to 50 silicon atoms, comprising at least one epoxy group and at least two epoxy groups Those having a silicon atom-bonded alkoxy group are more preferred.

The epoxy group is, for example, a silicon atom in the form of a glycidoxyalkyl group such as a glycidoxypropyl group; an epoxy-containing cyclohexylalkyl group such as a 2,3-epoxycyclohexylethyl group or a 3,4-epoxycyclohexylethyl group. It is preferable that it is couple | bonded with.
A silicon atom-bonded alkoxy group is bonded to a silicon atom, for example, a trialkoxysilyl group such as a trimethoxysilyl group or a triethoxysilyl group; a methyldimethoxysilyl group, an ethyldimethoxysilyl group, a methyldiethoxysilyl group, an ethyldi It is preferable to form an alkyl dialkoxysilyl group such as an ethoxysilyl group.

The component (F) is a functional group other than an epoxy group and a silicon atom-bonded alkoxy group in one molecule, such as an alkenyl group such as a vinyl group, an acrylic group, a (meth) acryloxy group, an isocyanate group, and a hydrosilyl group. You may have at least 1 type of functional group selected from the group which consists of group (SiH group).

Examples of the organosilicon compound of component (F) include γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, (3,4-epoxycyclohexylethyl) trimethoxysilane, (3, 4-epoxycyclohexylethyl) triethoxysilane, (3,4-epoxycyclohexylethyl) methyldimethoxysilane, (3,4-epoxycyclohexylethyl) methyldiethoxysilane, (2,3-epoxycyclohexylethyl) triethoxysilane, Epoxy group-containing silane coupling agents such as (2,3-epoxycyclohexylethyl) methyldimethoxysilane, (2,3-epoxycyclohexylethyl) methyldiethoxysilane (ie, epoxy-functional group-containing organoalkoxysilane) or Is a vinyl group-containing silane coupling agent such as vinyltrimethoxysilane, an acrylic group-containing silane coupling agent such as 3-acryloxypropyltrimethoxysilane, or an isocyanate group-containing silane coupling agent such as 3-isocyanatopropylethoxysilane. In addition to a silane coupling agent such as a methoxysilyl modified product of an agent or triallyl isocyanurate, a cyclic organopolysiloxane represented by the following chemical formula, or an organosilicon compound such as a linear organopolysiloxane, two or more of these Examples thereof include a mixture, or one or more partial hydrolysis condensates thereof.

（式中、ｈは１～１０の整数、ｋは０～４０の整数、好ましくは０～２０の整数、ｐは１～４０の整数、好ましくは１～２０の整数、ｑは１～１０の整数である。）

(In the formula, h is an integer of 1 to 10, k is an integer of 0 to 40, preferably 0 to 20, p is an integer of 1 to 40, preferably 1 to 20, and q is 1 to 10. (It is an integer.)

The blending amount of the component (F) is 0.1 to 10 parts by mass, preferably 0.25 to 5 parts by mass with respect to 100 parts by mass of the organopolysiloxane of the component (A). If the blending amount is less than 0.1 parts by mass, the resulting composition may not have sufficient adhesive strength. If the blending amount exceeds 10 parts by mass, the thixotropy of the composition is increased, the fluidity is lowered, and the coating workability may be deteriorated.

Moreover, when (F) component contains an alkenyl group and / or SiH group, 1 mol in total of the silicon atom bond alkenyl group contained in (A) component, (D) component, and (F) component in a composition The total amount of SiH groups contained in component (B) and component (F) relative to (or individual) is 1 to 10 mol (or individual), preferably 1.2 to 9 mol (or individual), more preferably 1.5 to 8 moles (or pieces). When the SiH group is less than 1 mole relative to 1 mole of silicon atom-bonded alkenyl groups in the composition, the composition may not be cured sufficiently and may not have sufficient adhesion. On the other hand, if it exceeds 10 moles, the resulting silicone rubber cured product is extremely inferior in heat resistance, making it difficult to improve the adhesive strength, increasing the cost, and being uneconomical.
(F) A component may be used individually by 1 type, or may use 2 or more types together.

[Other ingredients]
In addition to the components (A) to (F), the composition according to the present invention may contain other optional components as long as the object of the present invention is not impaired. Specific examples thereof include the following. Each of these other components may be used alone or in combination of two or more.

[(G) component]
The condensation catalyst of component (G) is at least one selected from an organic titanium compound, an organic zirconium compound, and an organoaluminum compound. In order to promote adhesion, the condensation aid of the adhesion-providing functional group in component (F) is used. It acts as a catalyst. Specific examples of the component (G) include, for example, organic titanates such as titanium tetraisopropoxide, titanium tetranormal butoxide, titanium tetra-2-ethylhexoxide, titanium diisopropoxybis (acetylacetonate), Titanium-condensation promoters (titanium compounds) such as titanium diisopropoxybis (ethyl acetoacetate), titanium tetraacetylacetonate, etc., organic zirconium esters such as zirconium tetranormal propoxide, zirconium tetranormal butoxide, Organic zirconium clay such as zirconium tributoxy monoacetylacetonate, zirconium monobutoxyacetylacetonate bis (ethylacetoacetate), zirconium tetraacetylacetonate Zirconium-based condensation promoters (zirconium compounds) such as compounds, organoaluminum acid esters such as aluminum secondary butoxide, organoaluminum chelate compounds such as aluminum trisacetylacetonate, aluminum bisethylacetoacetate monoacetylacetonate, and aluminum trisethylacetoacetate An aluminum-based condensation promoter such as

The organic titanium compound, organic zirconium compound, and organoaluminum compound of component (G) are optional components that are blended as necessary, and the blending amount is usually 5 masses per 100 parts by mass of component (A). However, when the component (G) is blended, it is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 2 parts by mass. When the blending amount is less than 0.1 parts by mass, the resulting cured product may be liable to deteriorate the adhesion durability under high temperature and high humidity. When the blending amount exceeds 5 parts by mass, the resulting cured product is obtained. May tend to lower the heat resistance.
(G) A component may be used individually by 1 type, or may use 2 or more types together.

-Reaction control agent A reaction control agent will not be specifically limited if it is a compound which has a hardening inhibitory effect with respect to the catalyst for hydrosilylation reaction of (E) component, A well-known thing can be used. Specific examples thereof include phosphorus-containing compounds such as triphenylphosphine; nitrogen-containing compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; sulfur-containing compounds; acetylene-based compounds such as acetylene alcohols; and containing two or more alkenyl groups. Compounds; hydroperoxy compounds; maleic acid derivatives and the like.

Since the degree of curing inhibition effect by the reaction control agent varies depending on the chemical structure of the reaction control agent, it is preferable to adjust the addition amount of the reaction control agent to an optimum amount for each of the reaction control agents to be used. By adding an optimal amount of the reaction control agent, the composition is excellent in long-term storage stability and curability at room temperature.

Non-reinforcing filler (C) As fillers other than the silica fine powder of component C, for example, crystalline silica (for example, quartz powder having a BET specific surface area of less than 50 m ² / g), hollow filler made of organic resin, poly Methyl silsesquioxane fine particles (so-called silicone resin powder), fumed titanium dioxide, magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, zinc carbonate, carbon black, diatomaceous earth, talc, kaolinite Fillers such as glass fibers; fillers obtained by subjecting these fillers to surface hydrophobization treatment with organosilicon compounds such as organoalkoxysilane compounds, organochlorosilane compounds, organosilazane compounds, and low molecular weight siloxane compounds; silicone rubber powders; silicone resins Such as powder. The

Other components In addition, for example, an organopolysiloxane containing one silicon-bonded hydrogen atom in one molecule and no other functional group, one silicon-bonded alkenyl group in one molecule An organopolysiloxane containing no other functional groups, a non-functional organopolysiloxane containing no silicon-bonded hydrogen atoms, silicon-bonded alkenyl groups, or other functional groups (so-called dimethyl silicone oil), An organic solvent, an anti-creep hardening agent, a plasticizer, a thixotropic agent, a pigment, a dye, an antifungal agent and the like can be blended.

<Preparation of addition-curable liquid silicone rubber composition>
In addition to the above components (A) to (F), the addition curable liquid silicone rubber composition can be prepared by uniformly mixing other components blended as required, such as the component (G). .
The addition-curable liquid silicone rubber composition thus obtained is a liquid composition at 25 ° C., and the viscosity at 25 ° C. measured by the method described in JIS K 7117-1: 1999 is 1,000 to 1,000. 000 mPa · s, preferably 10,000 to 300,000 mPa · s. If it is in this viscosity range, when coating on the airbag fabric, uneven coating and insufficient adhesion after curing are unlikely to occur, so that it can be suitably used.

<Base fabric for air bags>
In the present invention, a known base fabric (base material made of fiber cloth) for an air bag on which a silicone rubber layer made of a cured product of the above composition is formed is used, and specific examples thereof include 6, Examples include woven fabrics of various synthetic fibers such as various polyamide fibers such as 6-nylon, 6-nylon and aramid fibers, and various polyester fibers such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).

<Airbag manufacturing method>
By applying the addition curable liquid silicone rubber composition to at least one surface of a base fabric for an air bag (base material made of fiber fabric), in particular, one surface, and then heat-curing in a drying furnace or the like, A silicone rubber layer (cured material layer) can be formed. An airbag can be manufactured using the silicone rubber coating base fabric for airbags obtained in this way.

Here, as a method of coating the addition-curable liquid silicone rubber composition on the air bag base fabric (base material made of fiber fabric), a conventional method can be adopted, but coating with a knife coater is preferable. The thickness (or surface coating amount) of the coating layer is usually 10 to 100 g / m ² , preferably 12 to 90 g / m ² , more preferably 15 to 80 g / m ² .

The addition-curable liquid silicone rubber composition can be cured by a known curing method under known curing conditions. Specifically, for example, the composition can be cured by heating at 100 to 200 ° C. for 1 to 30 minutes.

When an airbag base fabric (silicone rubber coated base fabric for an airbag) having a silicone rubber layer on at least one surface thus manufactured is processed into an airbag, at least the inner surface side of the airbag is made of silicone rubber. There is a method in which the outer peripheral portions of two coated plain woven fabrics are bonded together with an adhesive, and the adhesive layers are sewn together. Further, as described above, the addition-curable liquid silicone rubber composition is coated at a predetermined coating amount on at least the inside of the airbag base fabric prepared by bag weaving in advance, and is cured under predetermined curing conditions. You may take a method. In addition, although a well-known thing can be used for the adhesive agent used here, the silicone type adhesive called a seam sealant is suitable from surfaces, such as adhesive force and adhesion durability.

Hereinafter, although a preparation example, an Example, and a comparative example are shown and this invention is demonstrated concretely, this invention is not restrict | limited to the following Example. The viscosity was measured with a rotational viscometer. Moreover, the part which concerns on a composition means a mass part, and room temperature means 25 degreeC.

[Preparation Example 1]
Viscosity of about 30,000 mPa · s and average degree of polymerization of 750 molecular chain both ends vinyldimethylsiloxy group-capped dimethylpolysiloxane (A1), hexamethyldisilazane 8 parts, the following formula (4) Polysiloxane (D1) having a vinyl group represented by 0.8 part, 2 parts of water, and silica fine powder (C) having a specific surface area of about 300 m ² / g by BET method (trade names: Aerosil 300, Nippon Aerosil) 40 parts) was mixed in a kneader for 1 hour. Thereafter, 8 parts of hexamethyldisilazane was added and further mixed for 1 hour. Next, the temperature in the kneader was raised to 150 ° C. and then mixed for 2 hours. Next, after the temperature was lowered to 100 ° C., 30 parts of a molecular chain-terminated vinyldimethylsiloxy-blocked dimethylpolysiloxane (A1) having a viscosity of about 30,000 mPa · s and an average degree of polymerization of 750 were added. The base compound (1) was obtained by mixing until uniform.

[Preparation Example 2]
Viscosity of about 30,000 mPa · s and average degree of polymerization of 750 molecular chain both ends vinyldimethylsiloxy group-capped dimethylpolysiloxane (A1), 8 parts hexamethyldisilazane, and the following formula (5) 0.58 parts of polysiloxane (D2) having a vinyl group at one end, 2 parts of water, and silica fine powder (C) having a specific surface area of about 300 m ² / g by BET method (trade name: Aerosil 300 , Manufactured by Nippon Aerosil Co., Ltd.) was mixed in a kneader for 1 hour. Thereafter, 8 parts of hexamethyldisilazane was added and further mixed for 1 hour. Next, the temperature in the kneader was raised to 150 ° C. and then mixed for 2 hours. Next, after the temperature was lowered to 100 ° C., 30 parts of a molecular chain-terminated vinyldimethylsiloxy-blocked dimethylpolysiloxane (A1) having a viscosity of about 30,000 mPa · s and an average degree of polymerization of 750 were added. The base compound (2) was obtained by mixing until uniform.

[Preparation Example 3]
Viscosity of about 30,000 mPa · s and average degree of polymerization of 750 molecular chain both ends vinyldimethylsiloxy group-blocked dimethylpolysiloxane (A1) 60 parts hexamethyldisilazane 8 parts 1,3-divinyl- 1,1,3,3-tetramethyldisilazane (D3) 0.1 part, water 2 part, and silica fine powder (C) having a specific surface area of about 300 m ² / g by BET method (trade name: Aerosil 300 , Manufactured by Nippon Aerosil Co., Ltd.) was mixed in a kneader for 1 hour. Thereafter, 8 parts of hexamethyldisilazane was added and further mixed for 1 hour. Next, the temperature in the kneader was raised to 150 ° C. and then mixed for 2 hours. Next, after the temperature was lowered to 100 ° C., 30 parts of a molecular chain-terminated vinyldimethylsiloxy-blocked dimethylpolysiloxane (A1) having a viscosity of about 30,000 mPa · s and an average degree of polymerization of 750 were added. The base compound (3) was obtained by mixing until uniform.

[Preparation Example 4]
60 parts molecular chain both ends vinyldimethylsiloxy group-blocked dimethylpolysiloxane (A1) having a viscosity of about 30,000 mPa · s and an average degree of polymerization of 750, 8 parts hexamethyldisilazane, 2 parts water, and BET 40 parts of silica fine powder (C) (trade name: Aerosil 300, manufactured by Nippon Aerosil Co., Ltd.) having a specific surface area of about 300 m ² / g according to the method was mixed for 1 hour in a kneader. Thereafter, 8 parts of hexamethyldisilazane was added and further mixed for 1 hour. Next, the temperature in the kneader was raised to 150 ° C. and then mixed for 2 hours. Next, after the temperature was lowered to 100 ° C., 30 parts of a molecular chain-terminated vinyldimethylsiloxy-blocked dimethylpolysiloxane (A1) having a viscosity of about 30,000 mPa · s and an average degree of polymerization of 750 were added. The base compound (4) was obtained by mixing until uniform.

[Example 1]
110 parts of the base compound (1) obtained in Preparation Example 1 were mixed with vinyldimethylsiloxy group-blocked dimethylpolysiloxane (A2) having a viscosity of about 100,000 mPa · s and an average degree of polymerization of 1,000. ) 59.5 parts, a molecular chain both ends dimethylhydrogen having a hydrogen atom bonded to a silicon atom at both ends of the molecular chain and a non-terminal end of the molecular chain having a viscosity of 12 mPa · s as a crosslinking agent and an average degree of polymerization of 18. Siloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer (B) (SiH group content 0.0035 mol / g) 8.5 parts (SiH group / vinyl group = 5.5 mol / mol), γ-glycidoxy 0.9 parts of propyltrimethoxysilane (F), 0.075 parts of 1-ethynylcyclohexanol, chloroplatinic acid / 1,3-divinyl A composition obtained by mixing 0.28 part of a dimethylpolysiloxane solution (E) containing 1% by mass of a platinum atom content of a tramethyldisiloxane complex and 0.26 part of zirconium tetraacetylacetonate (G) for 1 hour. A (viscosity 200 Pa · s) was prepared. Next, with respect to the composition A, the results of testing the rubber properties and the internal pressure retention of the cured product are shown in Table 1.

<Internal pressure retention test method>
The obtained liquid silicone rubber composition was uniformly coated on a single side of a bag-woven air bag manufactured from 66 nylon base fabric (210 denier) with a knife coater so as to be 50 g / m ^2, and in an oven at 180 ° C. It was cured by heating for 3 minutes. Thereafter, the other surface was similarly coated with silicone and heat cured at 180 ° C. for 3 minutes to produce a bag-woven airbag. Using this air bag, an internal pressure retention test was performed. In the internal pressure retention test, the airbag was inflated at a pressure of 100 kPa, the residual pressure after 30 seconds was measured, and this value was evaluated.

<Method for measuring rubber physical properties of cured product>
The prepared composition was press-cured at 150 ° C. for 5 minutes to prepare a 2.0 mm thick sheet, and this sheet was subjected to hardness, elongation at break, tensile strength, tearing by the method described in JIS K 6249: 2003. Strength was measured. The results are shown in Table 1.

[Example 2]
Composition B (SiH group / vinyl group = 5.5 mol / mol, except that the base compound (1) of Example 1 was replaced with the base compound (2) prepared in Preparation Example 2 with the same parts by mass. Viscosity of 190 Pa · s) was prepared, and the rubber physical properties and internal pressure retention of the cured product were tested in the same manner as in Example 1. Table 1 shows the results.

[Example 3]
Composition C (SiH group / vinyl group = 5.5 mol / mol, except that the base compound (1) of Example 1 was replaced with the base compound (3) prepared in Preparation Example 3 with the same parts by mass. Viscosity of 190 Pa · s) was prepared, and the rubber physical properties and internal pressure retention of the cured product were tested in the same manner as in Example 1. Table 1 shows the results.

[Comparative Example 1]
Composition D (SiH group / vinyl group = 6.5 mol / mol), except that the base compound (1) of Example 1 was replaced with the base compound (4) prepared in Preparation Example 4 with the same parts by mass. Viscosity of 180 Pa · s) was prepared, and the rubber physical properties and internal pressure retention of the cured product were tested in the same manner as in Example 1. Table 1 shows the results.

[Comparative Example 2]
In composition D prepared in Comparative Example 1, 0.8 part of vinyl group-containing polysiloxane (D1) represented by the above formula (4) was mixed at 25 ° C. for 15 minutes to obtain composition E (SiH group / vinyl group). = 5.5 mol / mol, viscosity 220 Pa · s), and the rubber physical properties and internal pressure retention of the cured product were tested in the same manner as in Example 1. Table 1 shows the results.

Claims (5)

(A) Organopolysiloxane having a degree of polymerization of 100 to 2,000 containing alkenyl groups bonded to two or more silicon atoms in one molecule: 100 parts by mass
(B) Organohydrogenpolysiloxane containing hydrogen atoms (SiH groups) bonded to at least two silicon atoms in one molecule: SiH groups contained in this component are the component (A) and the following (D) An amount of 1 to 10 moles per mole of silicon atom-bonded alkenyl groups contained in the component;
(C) Silica fine powder having a BET specific surface area of 50 m ² / g or more: 1 to 50 parts by mass,
(D) Surface treatment agent containing alkenyl group bonded to silicon atom (excluding component (A)): 0.01 to 5 parts by mass with respect to 100 parts by mass of silica fine powder of component (C) ,
(E) Catalyst for hydrosilylation reaction: 1 to 500 ppm in terms of the mass of the catalytic metal element with respect to the total mass of (A) to (D),
(F) Organosilicon compound containing an adhesion-imparting functional group (excluding components (A), (B), and (D)): characterized by having 0.1 to 10 parts by mass as an essential component Addition-curing liquid silicone rubber composition for airbags. The component (D) is selected from chlorosilanes having at least one vinyl group in one molecule, silazanes, and organosilicon compounds represented by the following formula (1) or (2). Addition-curable liquid silicone rubber composition for airbags.

(Wherein R ¹ is independently a monovalent saturated aliphatic hydrocarbon group having 1 to 12 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and R ² is independently a hydrogen atom or An alkyl group having 1 to 6 carbon atoms, n is an integer of 0 to 50, m is an integer of 1 to 50, and in the formula (2), the arrangement of each siloxane unit is random even if it is a block. May be good.) When the component (F) contains an alkenyl group and / or SiH group, the total amount per mole of silicon atom-bonded alkenyl groups contained in the component (A), the component (D), and the component (F) in the composition The addition-curable liquid silicone rubber composition for an air bag according to claim 1, wherein the total amount of SiH groups contained in the components (B) and (F) is 1 to 10 mol. Further, as component (G), at least one condensation catalyst selected from organic titanium compounds, organic zirconium compounds, and organoaluminum compounds is contained in an amount of 0.1 to 5 parts by mass with respect to 100 parts by mass of component (A). The addition-curable liquid silicone rubber composition for an air bag according to any one of claims 1 to 3, wherein An air bag comprising a cured coating of the addition-curable liquid silicone rubber composition for an air bag according to any one of claims 1 to 4 on a base fabric for the air bag.