阅读说明：本技术 加成固化型硅橡胶组合物及安全气囊 (Addition curing type silicone rubber composition and airbag ) 是由 水岛英典 芦田谅 生方茂 于 2018-06-06 设计创作，主要内容包括：本发明提供加成固化型硅橡胶组合物及安全气囊。加成固化型硅橡胶组合物,其特征在于,包含：(A)含有烯基的有机聚硅氧烷：100质量份；(B)有机氢聚硅氧烷：其量使得相对于(A)成分中的烯基1摩尔,(B)成分中的硅原子键合氢原子的摩尔数成为5摩尔以上；(C)加成反应催化剂：相对于(A)及(B)成分的合计质量,以催化剂金属元素的质量换算计,为1～500ppm；(D)微粉末二氧化硅：0.1～50质量份；(E)粘接性赋予剂[由(E-1)有机氢聚硅氧烷、(E-2)烷氧基甲硅烷基改性异氰脲酸酯化合物及(E-3)有机硅化合物组成的混合物]：0.1～5.0质量份；以及(F)缩合催化剂：0.1～5.0质量份。(The invention provides an addition curing type silicon rubber composition and an air bag. An addition-curable silicone rubber composition characterized by comprising: (A) alkenyl group-containing organopolysiloxane: 100 parts by mass; (B) organohydrogenpolysiloxane: in an amount such that the number of moles of hydrogen atoms bonded to silicon atoms in the component (B) is 5 moles or more relative to 1 mole of alkenyl groups in the component (A); (C) addition reaction catalyst: 1 to 500ppm in terms of the mass of the catalyst metal element relative to the total mass of the components (A) and (B); (D) fine powder silica: 0.1 to 50 parts by mass; (E) adhesion-imparting agent [ mixture of (E-1) organohydrogenpolysiloxane, (E-2) alkoxysilyl-modified isocyanurate compound, and (E-3) organosilicon compound ]: 0.1 to 5.0 parts by mass; and (F) a condensation catalyst: 0.1 to 5.0 parts by mass.)

1. An addition-curable silicone rubber composition characterized by comprising:

(A) an organopolysiloxane having 2 or more alkenyl groups having 2 to 8 carbon atoms bonded to silicon atoms in 1 molecule: 100 parts by mass;

(B) an organohydrogenpolysiloxane having 2 or more silicon atom-bonded hydrogen atoms in 1 molecule, represented by the following formula (1): the amount thereof is such that the number of moles of hydrogen atoms bonded to silicon atoms in the component (B) is 5 moles or more based on 1 mole of alkenyl groups in the component (A),

in the formula, R¹Is a C1-12 hydrocarbon radical, X is a hydrogen atom or R¹Wherein p is an integer of 1 to 50 and q is an integer of 1 to 50, and when p is 1, at least one X represents a hydrogen atom, the value of p/(p + q) is 0.1. ltoreq. p/(p + q) is 1;

(C) addition reaction catalyst: 1 to 500ppm in terms of the mass of the catalyst metal element relative to the total mass of the components (A) and (B);

(D) the specific surface area obtained by the BET method was 50m²A fine powder silica of at least g: 0.1 to 50 parts by mass;

(E) an adhesion-imparting agent which is a mixture of the following (E-1), (E-2) and (E-3): 0.1 to 5.0 parts by mass,

(E-1) an organohydrogenpolysiloxane represented by the following formula (2): 1 to 50% by mass of a binder,

in the formula, R²Independently a C1-valent hydrocarbon group having 1 to 12 carbon atoms, r is an integer of 5 to 50,

(E-2) an alkoxysilyl-modified isocyanurate compound represented by the following formula (3): 1 to 50% by mass of a binder,

in the formula, R³Independently an allyl group or a group represented by the following formula (4), R³At least 2 of which are groups represented by formula (4),

in the formula, R⁴Is a C1-6 hydrocarbon radical, R⁵Is an alkyl group of 1 to 4 carbon atoms, x is 2 or 3, and

(E-3) an organosilicon compound having 1 or more epoxy groups and alkoxysilyl groups in 1 molecule, respectively, and having no silicon atom-bonded hydrogen atom: 40 to 90% by mass of a binder,

wherein the total of the components (E-1) to (E-3) is 100 mass%; and

(F) a condensation catalyst comprising an organometallic compound selected from at least one of an organotitanium compound or an organozirconium compound: 0.1 to 5.0 parts by mass.

2. The addition curable silicone rubber composition according to claim 1, wherein component (a) comprises:

(A-1) a silicon compound having 2 or more alkenyl groups having 2 to 8 carbon atoms bonded to silicon atoms in 1 molecule, which is prepared by a method comprising the steps of: an alkenyl group-containing organopolysiloxane having a viscosity of 70000 mPas or more at 25 ℃ as measured by the method described in 2011; and

(A-2) a compound having 2 or more alkenyl groups having 2 to 8 carbon atoms bonded to silicon atoms in 1 molecule, which is produced by a method described in JIS Z8803: 2011 has a viscosity of 10000 to 50000 mPas at 25 ℃,

the mass ratio of the component (A-1) to the component (A-2) is 10: 90-90: 10.

3. the addition-curable silicone rubber composition according to claim 1 or 2, wherein the cured product obtained under the heat-curing conditions of 150 ℃ for 5 minutes is defined by JIS K6249: the elongation at break measured by the method described in 2003 is 1000% or more.

4. An airbag is characterized in that the base fabric is coated with 10-150 g/m²The surface coating amount of (3) is a cured coating film of the addition curable silicone rubber composition according to any one of claims 1 to 3.

5. An airbag according to claim 4 for a curtain airbag.

Technical Field

The present invention relates to an addition-curable silicone rubber composition and an airbag.

Background

Heretofore, a silicone rubber composition for an airbag has been proposed for forming a rubber coating on the surface of a fiber. Specifically, it is proposed that: an addition-curable liquid silicone rubber composition for an airbag, which is obtained by adding an inorganic filler, a silicone resin, and an epoxy group-containing silicon compound and has excellent adhesion to a base fabric (patent document 1: Japanese patent application laid-open No. 5-214295); an addition-curable liquid silicone rubber coating agent composition which is obtained by adding an inorganic filler, a silicone resin, an organotitanium compound and an alkyl silicate and exhibits excellent adhesion to a base fabric by heating at a low temperature for a short time (patent document 2: Japanese patent laid-open No. 2002-138249); a silicone rubber composition for an airbag excellent in film coatability which limits the viscosity of a vinyl group-containing organopolysiloxane (patent document 3: Japanese patent laid-open No. 2001-287610); and the specific surface area obtained by adding the BET method to the rubber coating composition is 150 to 250m on average²A coating composition for rubber-coated cloth which comprises wet silica having an average particle diameter of 20 μm or less in an amount of/g and which is reduced in the feeling of stickiness (patent document 4: Japanese patent laid-open No. 2001-059052).

However, unlike the case where these compositions are used for airbags mounted to driver's seats and assistant's seats, when the compositions are used for manufacturing curtain airbags that are stored along both sides of the roof from the front pillar and are required to maintain the expansion of the airbag for a certain period of time for head protection and flying out prevention at the time of a collision or at the time of a vehicle rollover, not all of the compositions suppress the leakage of inflation gas and sufficiently satisfy the durability of the expansion time.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide an addition-curable silicone rubber composition which has good adhesion to an airbag base fabric in addition to physical properties such as hardness, tensile strength, and elongation at break, and which can be used for producing an airbag such as a curtain airbag, which is excellent in suppressing leakage of inflation gas and in maintaining the inflation time, and an airbag.

Means for solving the problems

The present inventors have conducted intensive studies to achieve the above object, and as a result, have found that: a cured product obtained by curing an addition-curable silicone rubber composition containing a specific alkenyl group-containing organopolysiloxane (a), an organohydrogenpolysiloxane (B), an addition reaction catalyst (C), fine-powder silica (D), an adhesion-imparting agent (E), a mixture of an organohydrogenpolysiloxane (E-1), an alkoxysilyl-modified isocyanurate compound (E-2) and an organosilicon compound (E-3), and a condensation catalyst, has good adhesion to an airbag base fabric, suppresses leakage of inflation gas from an airbag, particularly an airbag, and is excellent in the durability of the inflation time, in addition to physical properties such as hardness, tensile strength, and elongation at break.

Accordingly, the present invention provides the following addition curable silicone rubber composition and airbag.

[1] An addition-curable silicone rubber composition characterized by comprising:

(A) an organopolysiloxane having 2 or more alkenyl groups having 2 to 8 carbon atoms bonded to silicon atoms in 1 molecule: 100 parts by mass of a water-soluble polymer,

(B) having 2 or more hydrogen atoms bonded to silicon atoms in 1 molecule represented by the following formula (1)

[ solution 1]

(in the formula, R¹Is a C1-12 hydrocarbon radical, X is a hydrogen atom or R¹Wherein p is an integer of 1 to 50 and q is an integer of 1 to 50, and when p is 1 and p/(p + q) ≦ 1, 0.1 is satisfied, at least one X represents a hydrogen atom. )

The organohydrogenpolysiloxane represented by: the amount thereof is such that the number of moles of hydrogen atoms bonded to silicon atoms in the component (B) is 5 moles or more based on 1 mole of alkenyl groups in the component (A),

(C) addition reaction catalyst: 1 to 500ppm in terms of the mass of the catalyst metal element relative to the total mass of the components (A) and (B),

(D) the specific surface area obtained by the BET method was 50m²A fine powder silica of at least g: 0.1 to 50 parts by mass of a stabilizer,

(E) an adhesion-imparting agent which is a mixture of (E-1), (E-2) and (E-3) below: 0.1 to 5.0 parts by mass,

(E-1) represented by the following formula (2)

[ solution 2]

(in the formula, R²Independently a C1-12 alkyl group, and r is an integer of 5 to 50. )

The organohydrogenpolysiloxane represented by: 1 to 50% by mass of a binder,

(E-2) represented by the following formula (3)

[ solution 3]

(in the formula, R³Independently is an allyl group or is represented by the following formula (4)

[ solution 4]

(in the formula, R⁴Is a C1-6 hydrocarbon radical, R⁵Is an alkyl group having 1 to 4 carbon atoms, and x is 2 or 3. ) A group represented by R³At least 2 of which are groups represented by formula (4). )

An alkoxysilyl-modified isocyanurate compound represented by: 1 to 50 mass%, and

(E-3) an organosilicon compound having 1 or more epoxy groups and alkoxysilyl groups in 1 molecule, respectively, and having no silicon atom-bonded hydrogen atom: 40 to 90 mass% (wherein the total of the (E-1) to (E-3) components is 100 mass%), and

(F) a condensation catalyst composed of an organometallic compound selected from at least one of an organotitanium compound or an organozirconium compound: 0.1 to 5.0 parts by mass.

[2] [1] the addition-curable silicone rubber composition is characterized in that the component (A) contains:

(A-1) a silicon compound having 2 or more alkenyl groups having 2 to 8 carbon atoms bonded to silicon atoms in 1 molecule, which is prepared by a method comprising the steps of: an alkenyl group-containing organopolysiloxane having a viscosity of 70000 mPas or more at 25 ℃ measured by the method described in 2011, and

(A-2) a compound having 2 or more alkenyl groups having 2 to 8 carbon atoms bonded to silicon atoms in 1 molecule, which is produced by a method described in JIS Z8803: an alkenyl group-containing organopolysiloxane having a viscosity of 10000 to 50000 mPas at 25 ℃ measured by the method described in 2011;

the mass ratio of the component (A-1) to the component (A-2) is 10: 90-90: 10.

[3] [1] the addition-curable silicone rubber composition according to [1] or [2], wherein a cured product obtained under heat-curing conditions of 150 ℃ for 5 minutes is defined in accordance with JIS K6249: the elongation at break measured by the method described in 2003 is 1000% or more.

[4]An airbag characterized in that the base fabric is coated with 10 to 150g/m²Has a surface coating amount of [1]]～[3]A cured coating film of any one of the addition curable silicone rubber compositions.

[5] [4] the airbag according to the above, characterized by being used for a curtain airbag.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide an addition-curable silicone rubber composition which has good adhesion to an airbag base fabric in addition to physical properties such as hardness, tensile strength, and elongation at break, and which is useful for producing an airbag such as a curtain airbag having excellent durability of inflation time and suppressed leakage of inflation gas, and an airbag.

Detailed Description

< addition curing type silicone rubber composition >

The addition curable silicone rubber composition of the present invention contains the following components (a) to (F), and is liquid at room temperature (25 ℃). Hereinafter, each component will be described in detail. The viscosity described in the present specification is a viscosity measured according to JIS Z8803: 2011 the viscosity at 25 ℃ measured by the method described above is a value measured by a rotational viscometer.

(A) Organopolysiloxane containing alkenyl groups

(A) The organopolysiloxane of component (a) is a component that becomes a main component of the composition, and contains an average of 2 or more, preferably an average of 20 upper limits, and particularly preferably an average of 10 upper limits, of alkenyl groups bonded to silicon atoms in 1 molecule.

The alkenyl group bonded to a silicon atom usually has 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples thereof include vinyl, allyl, propenyl, butenyl, pentenyl, hexenyl, cyclohexenyl, heptenyl and the like, and vinyl is preferable. The bonding position of the alkenyl group bonded to the silicon atom in the organopolysiloxane molecule of component (a) may be either a molecular chain end or a molecular chain non-end (i.e., a molecular chain side chain other than a molecular chain end), or both.

Examples of the silicon atom-bonded organic group other than the silicon atom-bonded alkenyl group generally include a substituted or unsubstituted 1-valent hydrocarbon group having 1 to 12, preferably 1 to 10, carbon atoms and no aliphatic unsaturated bond. Specific examples thereof include alkyl groups such as methyl, ethyl, propyl, isopropyl, isobutyl, tert-butyl, pentyl, hexyl and heptyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; aralkyl groups such as benzyl and phenethyl; halogenated alkyl groups such as chloromethyl group, 3-chloropropyl group, and 3, 3, 3-trifluoropropyl group, in which hydrogen atoms in these functional groups are substituted with halogen atoms such as chlorine atom and fluorine atom, and methyl group and phenyl group are preferable.

The content of the silicon atom-bonded alkenyl group in the component (a) is usually 0.001 to 10 mol%, preferably 0.01 to 5 mol%, based on all organic groups bonded to silicon atoms.

The molecular structure of the organopolysiloxane of component (a) is not particularly limited, and may be, for example, linear, cyclic, branched, etc., and it is preferable that the main chain consists essentially of R₂SiO_2/2A unit (diorganosiloxane unit, wherein R is a 1-valent hydrocarbon group) having R at both ends of the molecular chain₃SiO_1/2A unit (triorganosiloxy unit, wherein R is the same as described above) of a linear diorganopolysiloxane blocked. Wherein the so-called "main chain consists essentially of R₂SiO_2/2The "unit composed" means that R is usually 99 to 100 mol%, preferably 99.5 to 100 mol%, in the siloxane units constituting the main chain portion excluding both ends of the molecular chain₂SiO_2/2And (4) units.

In the above formula, the 1-valent hydrocarbon group represented by R usually has 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms. Specific examples thereof include the groups exemplified as specific examples of the silicon atom-bonded alkenyl group and the groups exemplified as specific examples of the silicon atom-bonded organic group other than the silicon atom-bonded alkenyl group.

The viscosity of the organopolysiloxane of component (A) is preferably 100 to 500000 mPas, more preferably 10000 to 200000 mPas, in view of the good physical properties of the resulting cured product such as hardness, elongation at break, and tear strength, and the good workability of handling the composition.

(A) The organopolysiloxane of component (a) is preferably represented by the following average composition formula (5):

[ solution 5]

R² _aR³ _bSiO_(4-a-b)/2(5)

(in the formula, R²Is alkyl with 1-12 carbon atoms or aryl with 6-12 carbon atoms, R³Independently an alkenyl group having 2 to 8 carbon atoms, a is a positive number of 1.8 to 2.2, preferably 1.9 to 2.0, and b is a positive number of 0.0001 to 0.2, preferably 0.001 to 0.1, but a + b is a positive number of 1.85 to 2.3, preferably 1.95 to 2.05. ) And (4) showing.

In the formula (5), R²The group is selected from an alkyl group having 1 to 12 carbon atoms, preferably 1 to 10 carbon atoms, and an aryl group having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms, and specific examples thereof include groups exemplified as silicon atom-bonded organic groups other than the silicon atom-bonded alkenyl group.

In the formula (5), by R³The alkenyl group is usually 2 to 8 carbon atoms, preferably 2 to 4 carbon atoms. Specific examples thereof include the groups exemplified above as the alkenyl group bonded to the silicon atom.

Specific examples of the organopolysiloxane of component (A) include trimethylsiloxy-terminated dimethylsiloxane-methylvinylsiloxane copolymer at both molecular chain terminals, trimethylsiloxy-terminated methylvinylsiloxane at both molecular chain terminals, trimethylsiloxy-terminated dimethylsiloxane-methylvinylsiloxane copolymer at both molecular chain terminals, dimethylvinylsiloxy-terminated dimethylpolysiloxane at both molecular chain terminals, dimethylvinylsiloxy-terminated methylvinylsiloxane at both molecular chain terminals, and dimethylvinylsiloxy-terminated methylvinylsiloxane at both molecular chain terminalsThe polysiloxane, dimethyl vinyl siloxy-terminated dimethyl siloxane-methyl vinyl siloxane copolymer at two ends of a molecular chain, dimethyl vinyl siloxy-terminated dimethyl siloxane-methyl vinyl siloxane-methyl phenyl siloxane copolymer at two ends of a molecular chain, divinyl methyl siloxy-terminated dimethyl polysiloxane at two ends of a molecular chain, divinyl methyl siloxy-terminated dimethyl siloxane-methyl vinyl siloxane copolymer at two ends of a molecular chain, trivinyl siloxy-terminated dimethyl polysiloxane at two ends of a molecular chain, trivinyl siloxy-terminated dimethyl siloxane-methyl vinyl siloxane copolymer at two ends of a molecular chain, and the polysiloxane is prepared by the following formula: r² ₃SiO_0.5(in the formula, R²As described above. ) Siloxane units and formula shown: r² ₂R³SiO_0.5(in the formula, R³As described above. ) Siloxane units and formula shown: r² ₂Siloxane units represented by SiO and formula: SiO 2₂An organosiloxane copolymer comprised of siloxane units represented by the formula: r² ₃SiO_0.5Siloxane units and formula shown: r² ₂R³SiO_0.5Siloxane units and formula shown: SiO 2₂An organosiloxane copolymer comprised of siloxane units represented by the formula: r² ₂R³SiO_0.5Siloxane units and formula shown: r² ₂Siloxane units represented by SiO and formula: SiO 2₂An organosiloxane copolymer comprised of siloxane units represented by the formula: r²R³Siloxane units represented by SiO and formula: r²SiO_1.5Siloxane units or formula shown: r³SiO_1.5Organosiloxane copolymers composed of the siloxane units shown, and the like.

(A) The organopolysiloxane of component (a) may be used alone in 1 kind, or 2 or more kinds may be used in combination.

When 2 or more species are used in combination, the composition preferably contains: (A-1) an alkenyl group having at least 2 carbon numbers 2 to 8 in 1 molecule, obtained by JIS Z8803: an alkenyl group-containing organopolysiloxane having a viscosity of 70000 mPas or more, preferably 80000 to 120000 mPas at 25 ℃ as measured by the method described in 2011; and (A-2) an alkenyl group having at least 2 carbon numbers 2 to 8 in 1 molecule, as measured by JIS Z8803: an alkenyl group-containing organopolysiloxane having a viscosity at 25 ℃ of 10000 to 50000 mPas, preferably 20000 to 40000 mPas, as measured by the method described in 2011.

The mixing ratio of the component (A-1) to the component (A-2), expressed as a mass ratio, is preferably 10: 90-90: 10. within this range, the leakage of inflation gas is suppressed, and the durability of the inflation time can be improved.

(B) Organohydrogenpolysiloxanes

The organohydrogenpolysiloxane of component (B) is an essential component, in which silicon atoms in the molecule are bonded to hydrogen atoms (i.e., SiH groups) and alkenyl groups in component (a) form a crosslinked structure by hydrosilylation addition reaction to cause curing, and is used as a crosslinking agent for producing a silicone rubber cured product having practically sufficient strength. The organohydrogenpolysiloxane is represented by the following general formula (1).

[ solution 6]

(in the formula, R¹Represent the same or different unsubstituted or substituted 1-valent hydrocarbon groups without aliphatic unsaturated bonds, and X independently represents a hydrogen atom or R¹P is an integer of 1 to 50, q is an integer of 1 to 50, but represented by the formula: when t represented by t/(p + q) satisfies 0.1. ltoreq. t.ltoreq.1 and p is 1, at least one X represents a hydrogen atom. )

R in the formula (1)¹The aliphatic unsaturated bond-free, unsubstituted or substituted, 1-to 12-valent hydrocarbon group having 1 to 8 carbon atoms, which may be the same or different from each other. As R¹Specific examples of the alkyl group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, hexyl, octyl and decyl; aryl groups such as phenyl, tolyl, xylyl, and naphthyl; cycloalkyl groups such as cyclohexyl; aralkyl groups such as benzyl and phenylethyl; chloromethyl, bromoethyl,Halogen-substituted hydrocarbon groups such as trifluoropropyl groups; cyano-substituted hydrocarbon groups such as cyanoethyl. Of these, methyl and phenyl groups are preferred. In the formula (1), all R¹Organohydrogenpolysiloxane of methyl or phenyl and R¹The organohydrogenpolysiloxane in which a part of the groups is methyl and the remainder is phenyl is easy to synthesize and has good chemical stability.

In addition, in the formula (1), p is an integer of 1 to 50, preferably 2 to 25, more preferably 3 to 25, further preferably 5 to 20, q is an integer of 1 to 50, preferably 1 to 30, more preferably 5 to 25, t satisfies 0.1. ltoreq. t.ltoreq.1, preferably 0.2. ltoreq. t.ltoreq.0.5, and when p is 1, at least one X represents a hydrogen atom.

Specific examples of the organohydrogenpolysiloxane of component (B) include trimethylsiloxy-terminated methylhydrogenpolysiloxane at both terminals, trimethylsiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymer at both terminals, dimethylsiloxy-terminated methylhydrogensiloxane at both terminals, dimethylsiloxy-terminated dimethylsiloxane-methylhydrogensiloxane copolymer at both terminals, trimethylsiloxy-terminated methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymer at both terminals, trimethylsiloxy-terminated methylhydrogensiloxane-methylphenylsiloxane-dimethylsiloxane copolymer at both terminals, and the like, And organohydrogenpolysiloxanes satisfying the condition of the above formula (1) among dimethylhydrogensiloxy terminated methylhydrogensiloxane-diphenylsiloxane copolymer at both ends, dimethylhydrogensiloxy terminated methylhydrogensiloxane-methylphenylsiloxane copolymer at both ends, dimethylhydrogensiloxy terminated methylhydrogensiloxane-dimethylsiloxane-diphenylsiloxane copolymer at both ends, and dimethylhydrogensiloxy terminated methylhydrogensiloxane-dimethylsiloxane-methylphenylsiloxane copolymer at both ends.

In the present invention, 1 kind of the organohydrogenpolysiloxane represented by the above formula (1) may be used alone, or 2 or more kinds may be used in combination.

The organohydrogenpolysiloxane represented by the above formula (1) was prepared according to JIS Z8803: 2011 is preferably 1 to 500 mPas, more preferably 5 to 100 mPas, at 25 ℃.

(B) The compounding amount of the components is as follows: the number of moles of the silicon atom-bonded hydrogen atoms in the component (B) is usually 5 moles or more, preferably 5 to 10 moles, and more preferably 5 to 7 moles, based on 1 mole of the silicon atom-bonded alkenyl groups in the component (A). If the amount of the compound (A) is less than 5 moles per 1 mole of the silicon atom-bonded alkenyl group in the component (A) and the amount of the silicon atom-bonded hydrogen atom in the component (B), the elongation at break of the resulting composition tends to be insufficient. If the amount of the silicon atom-bonded alkenyl group (a) is more than 10 moles based on 1 mole of the silicon atom-bonded alkenyl group (B), the heat resistance of the obtained silicone rubber tends to be extremely poor.

The amount of component (B) is 1 to 30 parts by mass, preferably 2 to 20 parts by mass, based on 100 parts by mass of the organopolysiloxane of component (A).

(C) Catalyst for addition reaction

The addition reaction catalyst of the component (C) promotes the addition reaction of the alkenyl group bonded to the silicon atom in the component (a) and the SiH group in the component (B). The addition reaction catalyst is not particularly limited, and examples thereof include platinum group metals such as platinum, palladium, and rhodium; chloroplatinic acid; alcohol-modified chloroplatinic acid; coordination compounds of chloroplatinic acid with olefinic, vinylsiloxane or acetylenic compounds; platinum group metal compounds such as tetrakis (triphenylphosphine) palladium and chlorotris (triphenylphosphine) rhodium, and the like, preferably platinum group metal compounds.

The amount of component (C) to be added may be an effective amount as a catalyst, and is preferably 1 to 500ppm, more preferably 10 to 100ppm, in terms of the mass of the catalyst metal element, based on the total mass of components (A) and (B). If the amount is too small, the addition reaction may be significantly slow, or the composition may not be cured, and if the amount is too large, the heat resistance of the cured product may be reduced.

(C) The catalyst for addition reaction of the components may be used alone in 1 kind, or 2 or more kinds may be used in combination.

(D) Fine powder silica

The fine-powder silica of the component (D) functions as a reinforcing material to impart high tear strength to a cured product, thereby forming a coating film having excellent tear strength. The fine powder silica is required to have a specific surface area of 50m by the BET method²A concentration of at least one member selected from the group consisting of 50 to 400m²A concentration of 100 to 300m is more preferable²(ii) in terms of/g. In the specific surface area of less than 50m²In the case of the specific ratio of the component (a)/g, sufficient tear strength may not be imparted to the composition.

The fine-particle silica as the component (D) can be a known fine-particle silica that has been conventionally used as a reinforcing filler for silicone rubber, provided that the specific surface area obtained by the BET method falls within the above range. Specific examples thereof include precipitated silica, fumed silica, and fired silica. These fine powder silicas can be used as they are, but from the viewpoint of imparting good fluidity to the composition, it is preferable to use a fine powder silica obtained by using a hexaorganodisilazane such as hexamethyldisilazane, divinyltetramethyldisilazane, dimethyltetravinyldisilazane or the like; alkoxysilanes such as methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, dimethyldimethoxysilane, diethyldimethoxysilane, vinyltriethoxysilane, vinyltrimethoxysilane, trimethylmethoxysilane, triethylmethoxysilane, vinyltris (methoxyethoxy) silane and divinyldimethoxysilane; methylchlorosilanes such as trimethylchlorosilane, dimethyldichlorosilane and methyltrichlorosilane; hydrophobic finely powdered silica having been subjected to surface hydrophobization treatment with an organic silicon compound such as dimethylpolysiloxane having no alkenyl group bonded to a silicon atom and no hydrogen atom bonded to a silicon atom.

The amount of the component (D) to be blended is 0.1 to 50 parts by mass, preferably 1 to 50 parts by mass, and more preferably 5 to 40 parts by mass, based on 100 parts by mass of the organopolysiloxane of the component (A). If the amount is too small, excellent tear strength may not be obtained, and if the amount is too large, the fluidity of the composition may be lowered and the coating operation may be deteriorated.

(D) The fine powder silica of component (A) may be used alone in 1 kind, or 2 or more kinds may be used in combination.

(E) Adhesion imparting agent

(E) The component (a) adhesiveness-imparting agent is used for improving the adhesiveness of the composition to a synthetic fiber woven fabric substrate, a nonwoven fabric substrate, a thermoplastic resin sheet-like or film-like substrate, or the like for an airbag. The adhesive property-imparting agent is capable of improving the self-adhesive property of the composition, and is characterized by using an organohydrogenpolysiloxane, an alkoxysilyl-modified isocyanurate compound and an organosilicon compound, which are represented by the following (E-1) to (E-3) components, in combination.

Wherein the total of the components (E-1) to (E-3) is 100% by mass.

(E-1) Organohydrogenpolysiloxane

(E-1) the component is represented by the following formula (2)

[ solution 7]

The organohydrogenpolysiloxane is composed of only diorganosiloxy groups having hydrogen atoms in the side chains and triorganosiloxy groups at the terminals. Wherein R is²Independently a C1-12 hydrocarbon group, exemplified by the group R¹R is an integer of 5 to 50, preferably an integer of 10 to 40. The component (E-1) is 1 to 50 mass%, preferably 5 to 30 mass% of the total amount of the component (E).

In the present invention, the amount of silicon atom-bonded hydrogen atoms contained in the component (E-1) is very small compared to the amount of silicon atom-bonded hydrogen atoms contained in the component (B), and the silicon atom-bonded hydrogen atoms of the component (E-1) are considered to be one point of the silicon atom-bonded hydrogen atoms to be subjected to the crosslinking reaction with the component (a) in order to impart adhesiveness to the present composition. Therefore, in order to determine the amount of the component (B) to be blended, the amount of the silicon atom-bonded hydrogen atom of the component (E-1) is not considered in calculating the ratio of the silicon atom-bonded hydrogen atom of the component (B) to the alkenyl group of the component (A).

(E-2) alkoxysilyl-modified isocyanurate Compound

(E-2) the component is represented by the following formula (3)

[ solution 8]

The alkoxysilyl-modified isocyanurate compound represented by (1). Wherein R is³Independently is an allyl group or is represented by the following formula (4)

[ solution 9]

A group represented by the formula (II) wherein R⁴Is C1-6 alkyl, preferably methyl or ethyl, R⁵Is alkyl with 1 to 4 carbon atoms, preferably methyl, x is 2 or 3, preferably 3, R³At least 2, preferably 3, of (a) are all groups represented by formula (4). The component (E-2) is 1 to 50 mass%, preferably 5 to 30 mass% of the total amount of the component (E).

In the present invention, when the component (E-2) has an allyl group, the amount of the alkenyl group contained in the component (a) is very small, and the allyl group of the component (E-2) is considered to be a little to be involved in the crosslinking reaction with the component (B) in order to impart adhesiveness to the present composition. Therefore, in order to determine the amount of the component (B) to be blended, the amount of allyl group in the component (E-2) is not considered in calculating the ratio of the silicon atom-bonded hydrogen atom in the component (B) to the alkenyl group in the component (A).

(E-3) organosilicon Compound

The component (E-3) is an organosilicon compound having 1 or more, preferably 1 to 10, epoxy groups and alkoxysilyl groups in 1 molecule and having no hydrogen atom bonded to a silicon atom. Examples of the epoxy group include a 2, 3-epoxypropyl group, a 3-glycidoxypropyl group, a 2- (3, 4-epoxycyclohexyl) ethyl group and the like, among which a 3-glycidoxypropyl group is preferable, and examples of the alkoxysilyl group include a trimethoxysilyl group, a triethoxysilyl group, a methyldimethoxysilyl group, a methyldiethoxysilyl group and the like, among which a trimethoxysilyl group is preferable. The component (E-3) is preferably 50 to 80% by mass based on 40 to 90% by mass of the total amount of the component (E).

Specific examples of the component (E-3) include the following examples.

[ solution 10]

The amount of component (E) to be blended [ (the total amount of components E-1 to E-3) ] is 0.1 to 5.0 parts by mass, preferably 0.1 to 2.0 parts by mass, based on 100 parts by mass of the organopolysiloxane of component (A). When the amount of the compound is too small, the resulting composition may not have sufficient adhesive strength, and when the amount is too large, the cost is increased, which is not economical.

(F) Condensation catalyst

(F) The condensation catalyst of component (E) is at least one selected from the group consisting of an organotitanium compound and an organozirconium compound, and functions as a co-condensation catalyst of component (E) for promoting adhesion. (F) The components can be used alone in 1 kind, or more than 2 kinds can be used together. Specific examples of the component (F) include titanium-based condensation cocatalysts (titanium compounds) such as organotitanates such as tetraisopropoxytitanium, tetra-n-butoxytitanium and tetra-2-ethylhexoxytitanium, organotitanium chelates such as diisopropoxybis (acetylacetonato) titanium, diisopropoxybis (ethylacetoacetate) titanium and tetraacetylacetonato titanium, and zirconium-based condensation cocatalysts (zirconium compounds) such as organozirconium esters such as tetran-propoxybis and tetra-n-butoxyzirconium, and organozirconium chelates such as tributoxymmonoacetylacetonato zirconium, monobutyoxyacetoacetoacetonato bis (ethylacetoacetate) zirconium and tetraacetylacetonato zirconium.

The amount of component (F) to be blended is 0.1 to 5.0 parts by mass, preferably 0.2 to 2.0 parts by mass, per 100 parts by mass of component (A). If the amount is less than 0.1 part by mass, the adhesion durability of the resulting cured product under high temperature and high humidity conditions may be easily reduced, and if the amount exceeds 5.0 parts by mass, the heat resistance of the resulting cured product may be easily reduced.

Other ingredients

In the composition of the present invention, other optional components may be blended in addition to the above components (a) to (F) within a range not impairing the object of the present invention. Specific examples thereof include the following components. These other components can be used alone in 1, can also be used in 2 or more.

Organosilicon Compounds

Specific examples of the organosilicon compounds other than the component (E-3) include the following.

[ solution 11]

CH₂＝CHSi(OCH₃)₃，O＝C＝N-C₃H₆-Si(OC₂H5)₃，

(wherein n is an integer of 1 to 98.)

The amount of the organosilicon compound is 0 to 3 parts by mass, preferably 0 to 1 part by mass, based on 100 parts by mass of the organopolysiloxane of the component (A).

Reaction control agent

The reaction control agent is not particularly limited as long as it is a compound having a curing reaction inhibiting action with respect to the addition reaction catalyst of the component (C), and conventionally known compounds can be used. Specific examples thereof include phosphorus-containing compounds such as triphenylphosphine; nitrogen atom-containing compounds such as tributylamine, tetramethylethylenediamine, and benzotriazole; a compound containing a sulfur atom; acetylene compounds such as acetylene alcohols; compounds containing 2 or more alkenyl groups; a hydroperoxide compound; maleic acid derivatives, and the like. The amount of the reaction control agent to be blended is preferably adjusted to an optimum amount for each reaction control agent to be used, because the degree of the curing reaction suppressing action of the reaction control agent varies depending on the chemical structure thereof. By blending an optimum amount of the reaction control agent, the composition is excellent in long-term storage stability at room temperature and curability.

Inorganic or organic filler materials

In the composition of the present invention, in addition to precipitated silica, fumed silica, fired silica, and the like, which are fine powder silica as the component (D), inorganic or organic fillers listed below may be added. Examples thereof include inorganic fillers such as crystalline silica, hollow fillers, silsesquioxane, fumed titanium dioxide, magnesium oxide, zinc oxide, iron oxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, zinc carbonate, layered mica, carbon black, diatomaceous earth, and glass fibers; a filler obtained by subjecting these to surface hydrophobization treatment with an organosilicon compound such as an organoalkoxysilane compound, an organochlorosilane compound, an organoazane compound, or a low-molecular-weight siloxane compound; silicone rubber powder; organic fillers such as silicone resin powder.

For example, an organopolysiloxane that does not contain both a hydrogen atom bonded to a silicon atom and an alkenyl group bonded to a silicon atom, water, a solvent such as an organic solvent, a creep-preventing curing agent, a plasticizer, a thixotropy-imparting agent, a pigment, a dye, a mildewproofing agent, and the like can be blended.

Preparation of addition-curable Silicone rubber composition

The components (a) to (F) thus obtained and, if necessary, other optional components are added and uniformly mixed to prepare a liquid addition curable silicone rubber composition.

In addition, such an addition-curable silicone rubber composition is preferably prepared by applying JIS K6249: the viscosity at 25 ℃ measured by the method described in 2003 is 10000 to 500000 mPas, particularly preferably 30000 to 300000 mPas, and if the viscosity is in this range, uneven application and poor adhesion after curing are less likely to occur when the coating is applied to a base fabric for an airbag, and therefore the coating can be preferably used.

< airbag >

The compositions of the present invention are useful in airbags, particularly curtain airbags.

Generally, as the base fabric for an airbag (base material made of a fiber fabric), a known base fabric is used, and specific examples thereof include fabrics of various polyamide fibers such as nylon 66, nylon 6, and aramid fibers, and various synthetic fibers such as various polyester fibers such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).

Then, the addition-curable silicone rubber composition is applied to at least one surface of such a base fabric for an airbag, and then cured by heating in a drying oven or the like, whereby a silicone rubber coating layer (cured material layer) can be formed on the base fabric.

In the case of manufacturing an airbag by forming a silicone rubber coating layer on a base fabric, the base fabric of a plain woven fabric may be processed into a tubular woven fabric (a coated article り) after forming the silicone rubber coating layer thereon, or the base fabric of a plain woven fabric may be previously processed into a tubular woven fabric and then formed into a silicone rubber coating layer thereon. In the tubular knitting process, a known bonding method or a known sewing method is used.

In the production of an airbag, as a method for applying the composition to the base fabric, a conventional method can be employed. The thickness (or surface coating amount) of the coating layer can be, for example, 10 to 150g/m in a dry state²Preferably 15 to 80g/m²More preferably 20 to 60g/m². The heat curing conditions of the composition can be usually 120 to 200 ℃, preferably 150 to 200 ℃, for 1 to 10 minutes, preferably 1 to 3 minutes.

Specifically, the cured product obtained under the heat curing conditions of 150 ℃ for 5 minutes was measured in accordance with JIS K6249: the elongation at break measured by the method described in 2003 is preferably 1000% or more, more preferably 1000 to 1500%. If the elongation at break is secured within such a range, the inflation gas leakage can be suppressed and the durability of the inflation time can be further improved.