Silicone rubber composition and silicone rubber-coated fabric

Abstract

The silicone rubber composition of the present invention comprises (A) a linear organopolysiloxane having at least two alkenyl groups in one molecule, (B) SiO 4 / 2 Units, R 1 2nd Round 2 SiO 1 / 2 Units and R 1 3SiO 1 / 2 Units (wherein R 1 are each independently an alkyl group having 1 to 12 carbon atoms, and R 2 is an alkenyl group having 2 to 12 carbon atoms.) and comprises at least a resinous organopolysiloxane containing 0.1 to 5.0 mass% of alkenyl groups, (C) an organopolysiloxane having at least two silicon-bonded hydrogen atoms per molecule, (D) a hydrosilylation reaction catalyst, (E) a reinforcing silica fine powder, and (F) an intumescent flame retardant. When applied to a woven fabric such as an airbag base fabric, this composition can impart sufficient flame retardancy even with a small coating amount and also can reduce the occurrence of openings.

Description

[Technical field]

[0001] The present invention relates to a silicone rubber composition and a silicone rubber-coated fabric using said composition. [Background technology]

[0002] Silicone rubber-coated fabrics, which are fabrics such as airbag base fabrics coated with a silicone rubber composition, are used in vehicle airbags, etc. In recent years, in order to store airbags more compactly, studies have been conducted on reducing the amount of silicone rubber composition applied, while studies have also been conducted on improving the flame retardancy of silicone rubber-coated fabrics.

[0003] In order to improve the flame retardancy of silicone rubber, for example, Patent Document 1 discloses a method for producing a silicone rubber by mixing a gas generating agent selected from the group consisting of compounds containing both phosphorus and nitrogen or a gas generating agent which is a mixture of a phosphorus-containing compound and a nitrogen-containing compound, and a compound represented by the formula: R 3 SiO 1 / 2 (wherein R is the same or different group selected from unsubstituted or substituted hydrocarbon groups having 1 to 30 carbon atoms), and an M unit represented by the formula: SiO 4 / 2 It has been proposed that a flame retardant additive consisting of a silicone resin containing as a main component a Q unit represented by the formula: can be added to rubber compositions such as construction sealants and LIMS. Patent Document 2 proposes a liquid silicone rubber composition for covering textiles which contains a reinforcing silica fine powder and aluminum hydroxide, but does not contain a solvent or a resinous organopolysiloxane. Patent Document 3 proposes the further blending of an organic phosphazene compound in a liquid silicone rubber composition for curtain airbags which contains an organopolysiloxane resin and silica fine powder. Patent Document 4 proposes a silicone rubber composition which contains fumed silica, a triazole compound, and a phosphate ester compound.

[0004] However, with such silicone rubber compositions, there are problems in that it is difficult to reduce the amount of silicone rubber composition applied, and the flame retardancy of the silicone rubber-coated fabric is insufficient, making it impossible to satisfy both requirements. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2005-226034 A [Patent Document 2] JP 2010-053493 A [Patent Document 3] JP 2014-136722 A [Patent Document 4] JP 2016-094514 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a silicone rubber composition that, when applied to a woven fabric such as an airbag base fabric, can impart sufficient flame retardancy even with a small application amount and can also reduce the likelihood of gaps forming. Another object of the present invention is to provide a silicone rubber-coated woven fabric that has excellent flame retardancy and is less likely to develop gaps even when a large tension is applied. [Means for solving the problem]

[0007] The silicone rubber composition of the present invention comprises: (A) 100 parts by mass of a linear organopolysiloxane having at least two alkenyl groups in one molecule, (B)SiO 4 / 2 Units, R 1 2 R 2 SiO 1 / 2 Units and R 1 3 SiO 1 / 2 Units (wherein R 1are each independently an alkyl group having 1 to 12 carbon atoms; R 2 is an alkenyl group having 2 to 12 carbon atoms.) 5 to 100 parts by mass of a resinous organopolysiloxane containing 0.1 to 5.0 mass % of alkenyl groups, (C) an organopolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule (an amount such that the number of silicon-bonded hydrogen atoms in this component is 0.5 to 10 moles per mole of alkenyl groups in components (A) and (B)); (D) a hydrosilylation catalyst in an amount sufficient to promote cure of the composition; (E) 0.1 to 50 parts by mass of reinforcing silica fine powder, and (F) Intumescent flame retardant 5 to 30 parts by mass The present invention is characterized in that it comprises at least

[0008] The present composition may further contain (G) an organotitanium compound and / or an organozirconium compound {0.01 to 10 parts by mass per 100 parts by mass of component (A)}, (H) an alkoxysilane containing an epoxy group and / or an alkoxysilane containing a methacryl group or an acrylic group {0.01 to 10 parts by mass per 100 parts by mass of component (A)}, (I) a silanol group-containing organosiloxane oligomer {0.01 to 10 parts by mass per 100 parts by mass of component (A)}, (J) an organoaluminum compound {0.01 to 10 parts by mass per 100 parts by mass of component (A)} or (K) aluminum hydroxide powder {5 to 50 parts by mass per 100 parts by mass of component (A)}, and such a composition is preferably a silicone rubber composition for coating a textile.

[0009] The silicone rubber coated fabric of the present invention is characterized in that it is produced by applying the silicone rubber composition of the present invention to the surface of a fabric and then curing the composition, and this fabric is preferably a base fabric for an airbag. Effect of the Invention

[0010] The silicone rubber composition of the present invention is characterized in that, when applied to a woven fabric such as an airbag base fabric, even a small amount of application can impart sufficient flame retardancy and furthermore, can make it difficult for gaps to form. Furthermore, the silicone rubber-coated woven fabric of the present invention is characterized in that it has excellent flame retardancy and is difficult for gaps to form even when a large tension is applied. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Silicone rubber composition> Component (A) is the main component of the composition and is a linear organopolysiloxane having at least two alkenyl groups in one molecule. Examples of the alkenyl groups in component (A) include alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, and decenyl groups, with vinyl groups being preferred. Examples of groups bonded to silicon atoms other than alkenyl groups in component (A) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, and heptyl groups; aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, and xylyl groups; aralkyl groups having 7 to 12 carbon atoms, such as benzyl and phenethyl groups; and halogenated alkyl groups having 1 to 12 carbon atoms, such as 3-chloropropyl and 3,3,3-trifluoropropyl groups, with methyl and phenyl groups being preferred. Furthermore, to the extent that the object of the present invention is not impaired, a small amount of hydroxyl groups or alkoxy groups, such as methoxy and ethoxy groups, may be bonded to silicon atoms in component (A).

[0012] The molecular structure of component (A) is substantially linear, but some of the molecular chain may be branched. The viscosity of component (A) is not limited, but is preferably within the range of 100 to 100,000 mPa·s, or 1,000 to 50,000 mPa·s at 25°C. If the viscosity of component (A) is equal to or higher than the lower limit of the above range, the mechanical strength of the silicone rubber is improved, whereas if the viscosity is equal to or lower than the upper limit of the above range, the coatability of the silicone rubber composition is improved. The viscosity of component (A) can be measured using a rotational viscometer in accordance with JIS K7117-1.

[0013] Examples of such organopolysiloxanes of component (A) include dimethylpolysiloxanes terminally blocked with dimethylvinylsiloxy groups, dimethylsiloxane-methylvinylsiloxane copolymers terminally blocked with dimethylvinylsiloxy groups, dimethylsiloxane-methylphenylsiloxane copolymers terminally blocked with dimethylvinylsiloxy groups, and methyl(3,3,3-trifluoropropyl)siloxane-methylvinylsiloxane copolymers terminally blocked with dimethylvinylsiloxy groups.

[0014] Component (B) is a resinous organopolysiloxane for improving the mechanical strength of the silicone rubber, and has the formula: SiO 4 / 2 Siloxanes of Q units, represented by the formula: R 1 2 R 2 SiO 1 / 2 Units and formulas: R 1 3 SiO 1 / 2 The siloxane is composed of M units represented by the formula: 1 are each independently an alkyl group having 1 to 12 carbon atoms, specific examples of which include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, and a heptyl group, and preferably a methyl group. 2is an alkenyl group having 2 to 12 carbon atoms, specifically exemplified by vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, and decenyl groups, with vinyl being preferred. Component (B) contains 0.1 to 5.0 mass%, preferably 0.5 to 5.0 mass%, or 0.5 to 2.5 mass% of alkenyl groups. Component (B) may contain other siloxane units, such as those represented by the formula: R, within the scope of the present invention. 1 2 SiO 2 / 2 Siloxanes with D units represented by the formula: R 1 SiO 3 / 2 In addition, the siloxane may contain a T unit represented by the formula: 1 is the same as above.

[0015] The resin-like organopolysiloxane of component (B) is, for example, SiO 4 / 2 Units and (CH 3 ) 3 SiO 1 / 2 Units and (CH 2 =CH)(CH 3 ) 2 SiO 1 / 2 Resin made of units, SiO 4 / 2 Units and (CH 3 ) 3 SiO 1 / 2 Units and (CH 2 =CH)(CH 3 ) 2 SiO 1 / 2 Units and (CH 3 ) 2 SiO 2 / 2 Resin made of units, SiO 4 / 2 Units and C 6 H 5 (CH 3 ) 2 SiO 1 / 2 Units and (CH 2 =CH)(CH 3 ) 2 SiO 1 / 2 Resin made of units, SiO 4 / 2 Units and (CH 3 ) 3 SiO 1 / 2Units and (CH 2 =CH)(CH 3 ) 2 SiO 1 / 2 Units and CH 3 SiO 3 / 2 In addition, resins that are liquid at room temperature, and even if they are solid, those that are compatible with component (A) are preferred.

[0016] The content of component (B) is within the range of 5 to 100 parts by mass, and preferably within the range of 10 to 80 parts by mass, per 100 parts by mass of component (A).This is because, when the content of component (B) is equal to or greater than the lower limit of the above range, the mechanical strength of the silicone rubber is improved, whereas, when the content is equal to or less than the upper limit of the above range, the viscosity of the silicone rubber composition is relatively low, making it possible to coat the base fabric without the use of a solvent.

[0017] Component (C) is a crosslinking agent for the composition, and is an organopolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule. Examples of silicon-bonded organic groups other than hydrogen atoms in component (C) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, and propyl groups; aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, and xylyl groups; and halogenated alkyl groups having 1 to 12 carbon atoms, such as 3-chloropropyl and 3,3,3-trifluoropropyl groups, with methyl and phenyl groups being preferred.

[0018] The molecular structure of component (C) is not limited, and examples include linear, branched, partially branched linear, cyclic, and resinous. The viscosity of component (C) is not limited, but preferably has a kinetic viscosity of 1 to 1,000 mm at 25°C. 2 / s range or 1 to 100 mm 2 / s. This is because, when the viscosity of component (C) is equal to or higher than the lower limit of the above range, the mechanical strength of the silicone rubber is improved, whereas, when the viscosity is equal to or lower than the upper limit of the above range, the coatability of the silicone rubber composition is improved. The viscosity of component (C) can be measured by an Ubbelohde viscometer conforming to JIS Z8803.

[0019] Examples of organopolysiloxanes of component (C) include methylhydrogenpolysiloxanes terminated with trimethylsiloxy groups at both molecular chain terminals, dimethylsiloxane-methylhydrogensiloxane copolymers terminated with trimethylsiloxy groups at both molecular chain terminals, methylphenylsiloxane-methylhydrogensiloxane copolymers terminated with dimethylphenylsiloxy groups at both molecular chain terminals, cyclic methylhydrogenpolysiloxanes, and copolymers of dimethylhydrogensiloxy units and SiO 4 / 2 Copolymers consisting of units are also included.

[0020] The content of component (C) is an amount such that the number of silicon-bonded hydrogen atoms in this organopolysiloxane is 0.5 to 10 moles, preferably 0.8 to 10 moles, 1 to 10 moles, or 1 to 5 moles, per mole of alkenyl groups in components (A) and (B) combined. This is because when the content of component (C) is at or above the lower limit of the above range, the silicone rubber composition is sufficiently cured, whereas when the content is at or below the upper limit of the above range, the heat resistance of the silicone rubber is improved.

[0021] The component (D) is a hydrosilylation catalyst for promoting the curing of the composition. The catalyst of the component (D) is exemplified by platinum group metal catalysts such as platinum catalysts, rhodium catalysts, ruthenium catalysts, iridium catalysts, and palladium catalysts, and is preferably a platinum catalyst. Examples of the platinum catalyst include platinum fine powder, chloroplatinic acid, alcohol solution of chloroplatinic acid, olefin complex of chloroplatinic acid, alkenylsiloxane complex of chloroplatinic acid, diketone complex of platinum, alkenylsiloxane complex of platinum, olefin complex of platinum; other metallic platinum supported on silica, alumina, carbon, etc.; and thermoplastic resin powder containing these platinum catalysts.

[0022] The content of component (D) is a catalytic amount, and is usually an amount in which the catalytic metal in component (D) is in the range of 0.1 to 500 parts by mass, and preferably in the range of 1 to 50 parts by mass, per 1 million parts by mass of component (A). This is because the reaction does not proceed sufficiently when it is less than 0.1 part by mass, and it is uneconomical when it exceeds 500 parts by mass.

[0023] Component (E) is a reinforcing silica fine powder that imparts mechanical strength to the silicone rubber obtained by curing the composition. Examples of component (E) include dry process silica, precipitated process silica, and hydrophobic silica in which the surface of these reinforcing silica fine powders has been treated with an organosilicon compound such as organochlorosilane, organosilazane, organoalkoxysilane, or organohydrogenpolysiloxane. In particular, component (E) is a silica fine powder having a specific surface area of ​​50 m 2 It is preferable that the molecular weight is 1 / g or more.

[0024] The content of component (E) is within the range of 0.1 to 50 parts by mass, and preferably within the range of 5 to 40 parts by mass, or within the range of 5 to 30 parts by mass, per 100 parts by mass of component (A).This is because, when the content of component (E) is equal to or greater than the lower limit of the above range, the mechanical strength of the silicone rubber is excellent, whereas, when the content is equal to or less than the upper limit of the above range, the coatability of the silicone rubber composition is good.

[0025] The (F) component is an intumescent flame retardant for improving the flame retardancy of silicone rubber, and is a mixture of at least one melamine salt selected from the group consisting of melamine orthophosphate, melamine pyrophosphate, and melamine polyphosphate, and at least one piperazine salt selected from the group consisting of piperazine orthophosphate, piperazine pyrophosphate, and piperazine polyphosphate, and optionally containing a hydrotalcite compound and cyclodextrin. The ratio of the melamine salt to the piperazine salt is not limited, but the mass ratio is preferably within the range of 20:80 to 50:50. In addition, when the hydrotalcite compound is contained, it is preferable that the hydrotalcite compound is contained in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total of the melamine salt and the piperazine salt. Such intumescent flame retardants are available, for example, as non-halogen intumescent flame retardants (ADK STAB FP-2100JC manufactured by ADEKA CORPORATION) and non-halogen intumescent flame retardants (ADK STAB FP-2500S manufactured by ADEKA CORPORATION). In the present invention, it has been discovered that by blending an intumescent flame retardant, which is known as a flame retardant for organic resins, into a silicone rubber composition, in particular a silicone rubber composition containing a resinous organopolysiloxane as component (B) and a reinforcing silica fine powder as component (E), it is possible to impart significant flame retardancy to a silicone rubber-coated fabric even if the amount of silicone rubber composition applied is reduced.

[0026] The content of component (F) is within the range of 5 to 30 parts by mass, and preferably 10 to 30 parts by mass, or 15 to 30 parts by mass, per 100 parts by mass of component (A). When the content of component (F) is equal to or greater than the lower limit of the above range, the flame retardancy of the silicone rubber-coated fabric is improved, whereas when the content is equal to or less than the upper limit of the above range, the coatability of the silicone rubber composition is improved.

[0027] The present composition may contain (G) an organotitanium compound and / or an organozirconium compound in order to maintain the adhesion of the silicone rubber to a silicone-rubber-coated fabric obtained by applying and curing the composition, even after the fabric has been stored for an extended period of time under high temperature and high humidity conditions.

[0028] Examples of the organic titanium compound of component (G) include organic titanate esters such as tetraisopropyl titanate, tetrabutyl titanate, and tetraoctyl titanate; organic acid titanium salts such as titanium acetate; and titanium chelate compounds such as diisopropoxybis(acetylacetonate)titanium and diisopropoxybis(ethyl acetate)titanium.

[0029] Examples of the organic zirconium compound of the component (G) include zirconium complexes having β-diketones (including alkyl group-substituted and fluorine atom-substituted) as ligands, such as zirconium tetraacetylacetonate, zirconium hexafluoroacetylacetonate, zirconium trifluoroacetylacetonate, tetrakis(ethyltrifluoroacetylacetonate)zirconium, tetrakis(2,2,6,6-tetramethyl-heptanedionate), zirconium dibutoxybis(ethylacetoacetate), and diisopropoxybis(2,2,6,6-tetramethyl-heptanedionate)zirconium. In particular, the organic zirconium compound is preferably an acetylacetonate complex of zirconium (including alkyl group-substituted and fluorine atom-substituted acetylacetonate).

[0030] In this composition, the content of component (G) is within the range of 0.01 to 10 parts by mass, and preferably within the range of 0.1 to 5 parts by mass, or within the range of 0.5 to 5 parts by mass, relative to 100 parts by mass of component (A). This is because, when the content of component (G) is equal to or greater than the lower limit of the above range, good adhesion can be imparted to poorly adhesive adherends such as textiles, while, when the content is equal to or less than the upper limit of the above range, the storage stability of the silicone rubber composition is improved.

[0031] The composition may also contain (H) an alkoxysilane containing an epoxy group and / or an alkoxysilane containing a methacryl group or an acrylic group in order to improve adhesion to poorly adhesive substrates such as textiles.

[0032] Examples of alkoxysilanes containing an epoxy group, component (H), include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 4-glycidoxybutyltrimethoxysilane, 5,6-epoxyhexyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane.

[0033] Furthermore, examples of alkoxysilanes containing a methacryl group or an acryl group, component (H), include 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyldimethoxysilane.

[0034] In this composition, the content of component (H) is within the range of 0.01 to 10 parts by mass, and preferably within the range of 0.1 to 5 parts by mass, or within the range of 0.5 to 5 parts by mass, per 100 parts by mass of component (A). This is because, when the content of component (H) is equal to or greater than the lower limit of the above range, good adhesion can be imparted to poorly adhesive substrates such as textiles, while, when the content is equal to or less than the upper limit of the above range, the storage stability of the silicone rubber composition is improved.

[0035] The composition preferably further contains (I) a silanol group-containing organosiloxane oligomer. Examples of groups bonded to silicon atoms in the component (I) include alkyl groups such as methyl, ethyl, propyl, butyl, pentyl, and hexyl; alkenyl groups such as vinyl, allyl, butenyl, pentenyl, hexenyl, and heptenyl; aryl groups such as phenyl, tolyl, and xylyl; aralkyl groups such as benzyl and phenethyl; and halogenated alkyl groups such as 3-chloropropyl and 3,3,3-trifluoropropyl. The molecular structure of the component (I) is not limited, and examples include linear, partially branched linear, cyclic, and branched, and is preferably linear. The viscosity of the component (I) at 25°C is not limited, but is preferably less than 100 mPa·s or within the range of 1 to 50 mPa·s.

[0036] Examples of such component (I) include methylvinylpolysiloxane terminally blocked with dimethylhydroxysiloxy groups, and dimethylsiloxane-methylvinylsiloxane copolymer terminally blocked with dimethylhydroxysiloxy groups.

[0037] In the present composition, the content of component (I) is not limited, but is within the range of 0.01 to 10 parts by mass, and preferably within the range of 0.1 to 5 parts by mass, or within the range of 0.5 to 5 parts by mass, relative to 100 parts by mass of component (A). This is because, when the content of component (I) is equal to or greater than the lower limit of the above range, good adhesion can be imparted to poorly adhesive adherends such as textiles, while, when the content is equal to or less than the upper limit of the above range, the storage stability of the silicone rubber composition is improved.

[0038] Furthermore, since the composition can improve its flame retardancy even if the content of component (F) is reduced, it is preferable to contain an organoaluminum compound (J). Examples of such component (J) include aluminum tris(acetylacetonate), aluminum tris(ethyl acetate), ethyl acetoacetate aluminum diisopropylate, aluminum tris(ethyl acetoacetate), alkyl acetoacetate aluminum isopropylate, aluminum monoacetylacetate bis(ethyl acetoacetate), aluminum monoisopropoxy monooleoxyethyl acetoacetate, aluminum di-n-butoxide monoethyl acetoacetate, aluminum di-isopropoxide monoethyl acetoacetate, aluminum isopropylate, mono-sec-butoxy aluminum diisopropylate, aluminum sec-butylate, and aluminum ethylate.

[0039] In the present composition, the content of component (J) is not limited, but is within the range of 0.01 to 10 parts by mass, and preferably within the range of 0.1 to 5 parts by mass, or within the range of 0.5 to 5 parts by mass, relative to 100 parts by mass of component (A). This is because when the content of component (J) is equal to or greater than the lower limit of the above range, the flame retardant effect of component (F) can be improved, whereas when the content is equal to or less than the upper limit of the above range, the storage stability of the silicone rubber composition is improved.

[0040] Furthermore, since the present composition can improve its flame retardancy even if the content of the (F) component is reduced, it is preferable that the composition contains (K) aluminum hydroxide powder. The particle size of the (K) component is not particularly limited, and for example, the average particle size is preferably within the range of 0.1 to 50 μm or 0.1 to 10 μm. The shape is also not limited, and examples thereof include spherical, approximately spherical, and crushed. Such (K) component is available, and examples thereof include aluminum hydroxide powder with an average particle size of 1.0 μm (trade name: Higilite H42M, manufactured by Showa Denko K.K.) and aluminum hydroxide with an average particle size of 1.0 μm that has been surface-treated with a silane coupling agent (Higilite H42STV, manufactured by Showa Denko K.K.).

[0041] In the present composition, the content of component (K) is not limited, but is within the range of 5 to 50 parts by mass, and preferably within the range of 10 to 50 parts by mass, or within the range of 10 to 30 parts by mass, relative to 100 parts by mass of component (A). This is because, when the content of component (K) is equal to or greater than the lower limit of the above range, the flame retardant effect of component (F) can be improved and the occurrence of openings can be further suppressed, whereas, when the content is equal to or less than the upper limit of the above range, the coatability of the silicone rubber composition is improved.

[0042] In addition, the present composition preferably contains a curing inhibitor in order to improve storage stability and ease of handling. Examples of the curing inhibitor include acetylene compounds such as 1-ethynylcyclohexane-1-ol, 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, and 2-phenyl-3-butyn-2-ol; ene compounds such as 3-methyl-3-penten-1-yne and 3,5-dimethyl-3-hexen-1-yne; triazoles such as benzotriazole; and phosphines, mercaptans, and hydrazines. The content of the curing inhibitor is not limited, but is preferably within the range of 0.001 to 10 parts by mass, or within the range of 0.01 to 10 parts by mass, relative to 100 parts by mass of the (A) component.

[0043] Furthermore, the composition may contain inorganic fillers other than components (E) and (K) to the extent that the object of the present invention is not impaired. Examples of such inorganic fillers include extender fillers such as quartz powder, diatomaceous earth, calcium carbonate, magnesium carbonate, etc.; heat-resistant agents such as cerium oxide, cerium hydroxide, iron oxide, etc.; pigments such as red iron oxide, titanium oxide, carbon black, etc.; and flame retardants.

[0044] The method for preparing the composition is not limited, and the composition can be prepared by mixing the components (A) to (F) and, if necessary, any other optional components. However, it is preferable to mix the remaining components (A), (B), (C), (D), and (F) with a silica master batch prepared in advance by heating and mixing a part of the component (A) with the component (E). If it is necessary to mix any other optional components, they may be mixed when preparing the silica master batch, and if they are altered by heating and mixing, it is preferable to mix them when mixing the remaining components (A), (B), (C), (D), and (F). In addition, when preparing the silica master batch, the above-mentioned organosilicon compound may be mixed to in-situ treat the surface of the component (E). When preparing the composition, a well-known kneading device such as a two-roll mill, a kneader mixer, or a Ross mixer may be used.

[0045] <Silicone rubber coated fabric> The silicone rubber-coated fabric of the present invention is obtained by coating the surface of a fabric with the silicone rubber composition and curing the composition.The fabric in the coated fabric is exemplified by polyamide fiber fabrics such as nylon 6, nylon 66, and nylon 46; polyester fiber fabrics such as polyethylene terephthalate, polybutylene terephthalate, and polytrimethylene terephthalate; and other fabrics such as polyacrylic fiber fabrics, polyacrylonitrile fiber fabrics, aramid fiber fabrics, polyetherimide fiber fabrics, polysulfone fiber fabrics, carbon fiber fabrics, rayon fiber fabrics, polypropylene fiber fabrics, and polyethylene fiber fabrics, or nonwoven fabrics made of these fibers.In particular, polyamide fiber fabrics or polyester fiber fabrics are preferable as the base fabric of airbags because they have excellent heat resistance and mechanical properties.

[0046] The weave of the covering fabric is not limited, and examples thereof include twill and plain weave. In terms of productivity and thickness, plain weave is generally used as the base fabric for airbags.

[0047] The method for producing the present coated textile is not limited, and for example, the silicone rubber composition can be applied to the textile by a known method such as spraying, gravure coating, bar coating, knife coating, patting, screen printing, dipping, etc. In this case, the amount of the silicone rubber composition for coating textiles to be applied is 10 to 100 g / m. 2 In general, the temperature range of the silicone rubber composition is within the range of 1 to 200° C. After the silicone rubber composition is applied, it can be cured by heating the composition at 150 to 200° C. for 1 to 2 minutes.

[0048] The coated fabric may have one silicone rubber coating layer or two or more layers. Furthermore, the coated fabric may have any additional coating layer as required. Such additional coating layers are generally intended to improve the feel of the surface of the coated fabric, further improve the abrasion resistance of the surface, or improve the strength of the coated fabric. Specific examples of such additional coating layers include coating layers made of plastic films, woven fabrics, nonwoven fabrics, and other elastic coating agents. EXAMPLES

[0049] The silicone rubber composition and silicone rubber-coated fabric of the present invention are described in more detail in the following examples. Note that the viscosity (mPa·s) in the examples is the value measured at 25°C using a rotational viscometer conforming to JIS K7117-1, and the kinetic viscosity (mm 2 / s) is a value measured at 25°C using an Ubbelohde viscometer conforming to JIS Z8803. The silicone rubber-coated fabric was prepared and evaluated as follows.

[0050] <Preparation of silicone rubber coated fabric> A silicone rubber composition was applied to one side of a nylon 66 woven fabric made of filament yarns with a total fiber count of 470 decitex and a warp density of 46 threads / inch and a weft density of 46 threads / inch using a lab coater in an amount of approximately 13 to 16 g / m 2 The silicone rubber composition was then cured by heating in an oven at 190° C. for 70 seconds to produce a silicone rubber-coated fabric.

[0051] [Flammability of silicone rubber-coated fabrics] The silicone rubber-coated fabric prepared as above was cut into a rectangular shape measuring 10 cm in length and 25 cm in width to serve as a test specimen, and its flammability was evaluated based on the burning rate. The burning rate (mm / min) was measured according to the method specified in the flammability test for automotive interior materials, FMVSS No. 302 (Federal Motor Vehicle safety Standards No. 302).

[0052] <Opening ability of silicone rubber coated fabric> A rectangular specimen 50 mm wide and 100 mm long was cut out from the silicone rubber-coated fabric prepared as described above. The 50 mm wide specimen was pierced 5 mm from the end with a jig having comb-like needles spaced 4 mm apart, and the jig and the other end of the specimen were set in a tensile tester and pulled at a tensile speed of 200 mm / min to measure the maximum tensile strength (N) until the specimen was pulled out of the evenly spaced comb-like needles. The opening property was evaluated based on this tensile strength, i.e., the end comb resistance (N).

[0053] <Preparation Example 1> A Ross mixer was charged with 100 parts by mass of dimethylpolysiloxane terminated at both ends with dimethylvinylsiloxy groups (vinyl group content = approximately 0.09% by mass) with a viscosity of 40,000 mPa s and a BET specific surface area of ​​225 m 2 40 parts by mass of fumed silica with a molecular chain density of 100 / g, 7 parts by mass of hexamethyldisilazane, 2 parts by mass of water, and 0.2 parts by mass of dimethylsiloxane-methylvinylsiloxane copolymer capped with dimethylhydroxysiloxy groups at both molecular chain ends and having a viscosity of 20 mPa s (vinyl group content: approximately 10.9% by mass) were added and mixed at room temperature until uniform. This was then heated under reduced pressure at 200°C for 2 hours to prepare a silica masterbatch with good fluidity.

[0054] <Examples 1 to 6 and Comparative Examples 1 to 4> A silicone rubber composition was prepared by uniformly mixing the following components to obtain the composition shown in Table 1. The properties of the resulting silicone rubber-coated fabric are shown in Table 1. In the formula, Me and Vi represent methyl and vinyl groups, respectively, and the molar ratio of silicon-bonded hydrogen atoms in component (C) to the total of alkenyl groups in components (A) and (B) in the composition was 2.7.

[0055] The following components were used as component (A): (a-1): Dimethylpolysiloxane terminated at both ends of the molecular chain with dimethylvinylsiloxy groups and a viscosity of 10,000 mPa s (vinyl group content = approximately 0.13% by mass)

[0056] The following components were used as component (B): (b-1):Average unit formula: (Me 3 SiO 1 / 2 ) 0.40 (ViMe 2 SiO 1 / 2 ) 0.04 (SiO 4 / 2 ) 0.56 An organopolysiloxane resin represented by the formula (vinyl group content: approximately 1.6% by mass)

[0057] The following components were used as component (C): (c-1): Kinematic viscosity 15mm 2 / s, average unit formula: (Me 3 SiO 1 / 2 ) 0.09 (Me 2 SiO 2 / 2 ) 0.32 (HMeSiO 2 / 2 ) 0.54 (MeSiO 3 / 2 ) 0.05 (content of silicon-bonded hydrogen atoms = approximately 0.83% by mass)

[0058] The following components were used as component (D): (d-1): 1,3-divinyltetramethyldisiloxane solution of platinum complex in 1,3-divinyltetramethyldisiloxane (platinum metal content = approx. 4,000 ppm)

[0059] The following components were used as component (E): (e-1): Silica masterbatch prepared in Preparation Example 1

[0060] The following components were used as component (F): (f-1): Non-halogen intumescent flame retardant (ADEKA STAB FP-2100JC manufactured by ADEKA Corporation) (f-2): Non-halogen intumescent flame retardant (ADEKA STAB FP-2500S manufactured by ADEKA Corporation)

[0061] In addition, the following components were used for comparison with component (F). (f-3): Non-halogen condensed phosphate ester flame retardant (ADEKA STAB FP-600 manufactured by ADEKA Corporation)

[0062] The following components were used as component (G): (g-1): Zirconium tetraacetylacetonate

[0063] The following components were used as component (H): (h-1): 3-glycidoxypropyltrimethoxysilane

[0064] The following components were used as components (I): (i-1): Organosiloxane oligomer containing silanol groups: Dimethylsiloxane-methylvinylsiloxane copolymer capped with dimethylhydroxysiloxy groups at both ends of the molecular chain with a viscosity of 20 mPa·s (vinyl group content: approximately 10.9% by mass)

[0065] The following components were used as component (J): (j-1): Aluminum acetylacetonate (j-2): Alkylacetoacetate aluminum diisopropylate (product name: PLENACT AL-M, manufactured by Ajinomoto Fine-Techno Co., Ltd.)

[0066] The following components were used as the (K) component: (k-1): Aluminum hydroxide powder with an average particle size of 1.0 μm (product name: Hijilite H42M, manufactured by Showa Denko K.K.)

[0067] In addition, the following components were used for comparison with the (K) component: (k-2): Magnesium hydroxide powder (Magseeds S manufactured by Konoshima Chemical Co., Ltd.)

[0068] The following components were used as cure inhibitors: (l-1): 1-ethynylcyclohexan-1-ol

[0069] [Table 1]

[0070] <Table 1 (continued)> [Table 2] [Industrial Applicability]

[0071] The silicone rubber composition of the present invention, when applied to a fabric such as a base fabric for an airbag, can impart sufficient flame retardancy even with a small amount of application and can also make it difficult for mesh to form, and is therefore suitable as a coating agent for fabrics used in applications such as airbags, such as curtain shield airbags, driver's airbags, passenger airbags, side airbags, knee airbags, ITS head airbags, aircraft emergency escape seats, inflatable rafts, etc. The silicone rubber-coated fabric of the present invention is also suitable as a base fabric for curtain shield airbags, aircraft emergency escape seats, etc.

Claims

1. (A) 100 parts by mass of a linear organopolysiloxane having at least two alkenyl groups in one molecule, (B) SiO ４ / ２ Units, R １ ２ R ２ SiO １ / ２ Units and R １ ３ SiO １ / ２ Units (wherein R １ are each independently an alkyl group having 1 to 12 carbon atoms; R ２ is an alkenyl group having 2 to 12 carbon atoms), and 5 to 100 parts by mass of a resin-like organopolysiloxane containing 0.1 to 5.0 mass % of alkenyl groups, (C) an organopolysiloxane containing at least two silicon-bonded hydrogen atoms per molecule (an amount such that the number of silicon-bonded hydrogen atoms in this component is 0.5 to 10 moles per mole of alkenyl groups in components (A) and (B)), (D) a hydrosilylation reaction catalyst in an amount sufficient to promote cure of the composition; (E) 0.1 to 50 parts by mass of reinforcing silica powder, and (F) Intumescent flame retardant: 5 to 30 parts by mass A silicone rubber composition comprising at least

2. 2. The silicone rubber composition according to claim 1, further comprising (G) an organotitanium compound and / or an organozirconium compound (0.01 to 10 parts by mass per 100 parts by mass of component (A)).

3. 2. The silicone rubber composition according to claim 1, further comprising (H) an alkoxysilane containing an epoxy group and / or an alkoxysilane containing a methacryl group or an acrylic group (0.01 to 10 parts by mass per 100 parts by mass of component (A)).

4. 2. The silicone rubber composition according to claim 1, further comprising: (I) a silanol group-containing organosiloxane oligomer (0.01 to 10 parts by mass per 100 parts by mass of component (A)).

5. 2. The silicone rubber composition according to claim 1, further comprising: (J) an organoaluminum compound (0.01 to 10 parts by mass per 100 parts by mass of component (A)).

6. 2. The silicone rubber composition according to claim 1, further comprising (K) aluminum hydroxide powder (5 to 50 parts by mass per 100 parts by mass of component (A)).

7. The silicone rubber composition according to any one of claims 1 to 6, which is used for coating textile fabrics.

8. 7. A silicone rubber-coated textile fabric obtained by applying the silicone rubber composition according to claim 1 to a surface of a textile fabric and curing the composition.

9. 9. The silicone rubber coated fabric according to claim 8, wherein the fabric is a base fabric for an airbag.

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