JP2008031450A - Silicone rubber composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a silicone rubber composition quickly expressing adhesive force to a silicone rubber and having high adhesive force. <P>SOLUTION: The silicone rubber composition essentially comprises (A) a diorganopolysiloxane having in one molecule on average at least two alkenyl groups, (B) an organopolysiloxane having in one molecule at least one X<SP>1</SP>(a silylalkyl group of the formula(1) when i=1) bound to a silicon atom and having in one molecule on average three or more silicon atom-bound hydrogen atoms, (C) an organopolysiloxane having in one molecule on average at least two silicon atom-bound hydrogen atoms, (D) calcium carbonate powder and (E) a hydrosilylation catalyst. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a hydrosilylation reaction-curable silicone rubber composition containing calcium carbonate powder.

  As a silicone rubber composition containing calcium carbonate powder and cured by hydrosilylation reaction, diorganopolysiloxane having at least two alkenyl groups in one molecule, having at least two silicon-bonded hydrogen atoms in one molecule Silicone rubber composition comprising calcium carbonate powder surface-treated with an organopolysiloxane, a platinum group metal catalyst, and a partially hydrolyzed condensate of tetraalkoxysilane (see JP-A-10-60281), at least 2 in one molecule Silicone rubber composition comprising diorganopolysiloxane having one alkenyl group, calcium carbonate powder, organopolysiloxane having at least two silicon-bonded hydrogen atoms in one molecule, and platinum group metal catalyst 038016, JP2002-2 5130 JP are known, such as Patent reference JP 2005-082661), these silicone rubber compositions are known to exhibit adhesion to silicone rubber.

  Since these silicone rubber compositions contain calcium carbonate powder, there is a problem that it takes time until a practical adhesive force to the silicone rubber is developed under relatively low curing conditions of 100 ° C. or less. In addition, in order to adjust the time required to develop the adhesive force to an appropriate range, it is necessary to blend a large amount of an expensive platinum catalyst, which is economically disadvantageous. Moreover, the silicone rubber composition containing the conventional calcium carbonate powder has insufficient adhesive force to the silicone rubber.

  JP-A-10-324805 describes a curable organopolysiloxane composition containing a branched siloxane / silalkylene copolymer containing a silicon atom-bonded hydrogen atom. There is no description or suggestion about adhesion to rubber.

Japanese Patent Laid-Open No. 10-60281 JP 2002-038016 A JP 2002-285130 A Japanese Patent Laying-Open No. 2005-086661 JP-A-10-324805

  An object of the present invention is to provide a silicone rubber composition that exhibits good adhesion to silicone rubber and has good adhesion to silicone rubber.

（式中、Ｒ^１は炭素原子数１〜１０のアルキル基もしくはアリール基であり、Ｒ^２は炭素原子数２〜１０のアルキレン基であり、Ｒ^３は炭素原子数１〜１０のアルキル基であり、ｉはＸ^ｉで示されるシリルアルキル基の階層を示し、階層数がｃのとき１〜ｃの整数であり、階層数ｃは１〜１０の整数であり、ｂ^ｉはｉが１のときは０〜２の整数であり、ｉが２以上のときは３未満の数であり、Ｘ^ｉ＋１はｉがｃ未満のときは該シリルアルキル基であり、ｉ＝ｃのときは水素原子である。）｝を一分子中に少なくとも１個有し、一分子中に平均３個以上のケイ素原子結合水素原子を有するオルガノポリシロキサン｛本発明組成物中のアルケニル基に対する本成分中のケイ素原子結合水素原子のモル比が０.０１〜２０となる量｝、
（Ｃ）一分子中に少なくとも平均２個のケイ素原子結合水素原子を有するオルガノポリシロキサン｛ただし、(Ｂ)成分を除く。｝｛本発明組成物中のアルケニル基に対する本成分中のケイ素原子結合水素原子のモル比が０.０１〜２０となる量｝
（Ｄ）炭酸カルシウム粉末 １〜２００質量部、および
（Ｅ）ヒドロシリル化反応用触媒（本発明組成物の硬化を促進する量）
から少なくともなることを特徴とする。 The silicone rubber composition of the present invention comprises (A) 100 parts by mass of diorganopolysiloxane having at least two alkenyl groups on average in one molecule,
(B) X ¹ bonded to a silicon atom {silylalkyl group represented by the following formula (1) when i = 1:

(In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms or an aryl group, R ² is an alkylene group having 2 to 10 carbon atoms, and R ³ is an alkyl group having 1 to 10 carbon atoms. There, i is the generation of a silylalkyl group represented by X ^i, an integer 1~c when the generation number c, the number of layers c is an integer of from 1 to 10, b ⁱ is i = 1 Is an integer from 0 to 2, when i is 2 or more, it is a number less than 3, X ^{i + 1} is the silylalkyl group when i is less than c, and when i = c is a hydrogen atom Is an organopolysiloxane having at least one silicon atom-bonded hydrogen atom in one molecule and having an average of 3 or more silicon-bonded hydrogen atoms in one molecule {silicon atoms in this component relative to alkenyl groups in the composition of the present invention} The amount by which the molar ratio of bonded hydrogen atoms is 0.01-20},
(C) Organopolysiloxane having an average of at least two silicon-bonded hydrogen atoms in one molecule {however, component (B) is excluded. } {Amount in which the molar ratio of silicon-bonded hydrogen atoms in this component to alkenyl groups in the composition of the present invention is 0.01 to 20}
(D) 1 to 200 parts by mass of calcium carbonate powder, and (E) a catalyst for hydrosilylation reaction (amount that promotes curing of the composition of the present invention)
It consists of at least.

または式：

{式中ｄは３または４であり、Ｒ^１は炭素原子数１〜１０のアルキル基もしくはアリール基であり、Ｙ^１はｉ＝１のときの下記式で示されるシリルアルキル基：

（式中、Ｒ^１は前記に同じであり、Ｒ^２は炭素原子数２〜１０のアルキレン基であり、ｉはＹ^ｉで示されるシリルアルキル基の階層を示し、階層数ｃは１または２であり、Ｙ^ｉ＋１は、階層数ｃが１のときは水素原子であり、階層数ｃが２のときは、ｉ＝１のとき上記シリルアルキル基であり、ｉ＝２のとき水素原子である。）}で示されるポリカルボシロキサンであることが、好ましい。また、（Ｂ）成分中のケイ素原子結合水素原子のモル数と前記（Ｃ）成分中のケイ素原子結合水素原子のモル数の比が、１：１〜１：１０であり、本組成物中のアルケニル基に対する、（Ｂ）成分中のケイ素原子結合水素原子と（Ｃ）成分中のケイ素原子結合水素原子の合計のモル比が、０.１〜１０となる量であることが好ましい。また、（Ｄ）成分は軽質（または沈降）炭酸カルシウム粉末であることが好ましい。 The component (B) has the formula:

Or the formula:

{Wherein d is 3 or 4, R ¹ is an alkyl group or aryl group having 1 to 10 carbon atoms, and Y ¹ is a silylalkyl group represented by the following formula when i = 1:

(Wherein R ¹ is the same as above, R ² is an alkylene group having 2 to 10 carbon atoms, i represents a hierarchy of the silylalkyl group represented by Y ⁱ , and the hierarchy number c is 1 or 2) Y ^{i + 1} is a hydrogen atom when the hierarchy number c is 1, and when the hierarchy number c is 2, it is the silylalkyl group when i = 1, and is a hydrogen atom when i = 2. .)} Is preferred. The ratio of the number of moles of silicon-bonded hydrogen atoms in component (B) to the number of moles of silicon-bonded hydrogen atoms in component (C) is 1: 1 to 1:10, It is preferable that the total molar ratio of the silicon atom-bonded hydrogen atom in the component (B) and the silicon atom-bonded hydrogen atom in the component (C) is 0.1 to 10 with respect to the alkenyl group. The component (D) is preferably light (or precipitated) calcium carbonate powder.

  Moreover, this invention composition may contain 1-100 mass parts of (F) silica powder with respect to 100 mass parts of (A) component further in this case, (A) component and (F) component previously in this case. Are preferably heated and mixed.

  The composition of the present invention is useful as an adhesive for silicone rubber, an adhesive for silicone rubber-coated cloth, or a sealant for silicone rubber-coated cloth.

  The silicone rubber composition of the present invention is characterized in that the adhesive force to the silicone rubber is rapidly developed and the adhesiveness to the silicone rubber is good. In addition, when the time required for developing the adhesive force is the same as before, the amount of expensive platinum catalyst used can be reduced, which is also economically advantageous. Furthermore, it has the feature that the adhesive force with respect to silicone rubber is large.

The silicone rubber composition of the present invention will be described in detail.
Component (A) is the main component of the silicone rubber composition of the present invention and is a diorganopolysiloxane having an average of at least two alkenyl groups in one molecule. Examples of the alkenyl group in component (A) include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, and a vinyl group is preferable. In addition, as the organic group bonded to the silicon atom other than the alkenyl group in the component (A), an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group; a phenyl group, a tolyl group, An aryl group such as a xylyl group; a halogenated alkyl group such as a 3-chloropropyl group and a 3,3,3-trifluoropropyl group are exemplified, and a methyl group and a phenyl group are preferred. Although the molecular structure of the component (A) is substantially linear, a part of the molecular chain may be somewhat branched as long as the object of the present invention is not impaired. The viscosity of component (A) at 25 ° C. is not limited, but is preferably in the range of 100 to 1,000,000 mPa · s, and particularly preferably in the range of 100 to 500,000 mPa · s.

  Examples of the diorganopolysiloxane of component (A) include dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain, dimethylsiloxane / methylvinylsiloxane copolymer blocked with dimethylvinylsiloxy group blocked at both ends of the molecular chain, Terminal trimethylsiloxy group-blocked dimethylsiloxane / methylvinylsiloxane copolymer, part or all of the methyl groups of these diorganopolysiloxanes are alkyl groups such as ethyl groups and propyl groups; aryl groups such as phenyl groups and tolyl groups; Diorganopolysiloxanes substituted with halogenated alkyl groups such as 3,3,3-trifluoropropyl groups, and some or all of the vinyl groups of these diorganopolysiloxanes are substituted with alkenyl groups such as allyl groups and propenyl groups Diorganopolysiloxanes, and these A mixture of two or more diorganopolysiloxanes is exemplified.

）を有する。 Component (B) is a component that characterizes the silicone rubber composition of the present invention, and is blended for the purpose of shortening the time for developing the adhesive strength of the composition of the present invention to the silicone rubber and improving the adhesive strength to the silicone rubber. Is. Component (B) is an organopolysiloxane having an average of 3 or more silicon-bonded hydrogen atoms in one molecule, and X ¹ bonded to at least one silicon atom in one molecule (lower when i = 1) Silylalkyl group represented by formula (1):

).

In the formula (1), R ¹ is an alkyl group having 1 to 10 carbon atoms such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an isopropyl group, a hexyl group, an octyl group; a phenyl group, a tolyl group, An aryl group such as a xylyl group, preferably an alkyl group having 1 to 10 carbon atoms, and particularly preferably a methyl group. In the formula (1), R ² is an alkylene group having 2 to 10 carbon atoms, and a linear alkylene group such as an ethylene group, a propylene group, a butylene group, or a hexylene group; a methylmethylene group, a methylethylene group, 1- Examples thereof include branched alkylene groups such as a methylpentylene group and 1,4-dimethylbutylene group. Among these, an ethylene group, a methylmethylene group, a hexylene group, a 1-methylpentylene group, and a 1,4-dimethylbutylene group are preferable. In the formula (1), R ³ is an alkyl group having 1 to 10 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, an isopropyl group, a hexyl group, and an octyl group. Among these, a methyl group or an ethyl group is preferable.

Wherein (1), i specifies the generation of a silylalkyl group represented by X ^i, the number of layers, i.e., the number of repetitions of the silylalkyl group is an integer of 1~c when c. The hierarchy number c is an integer of 1 to 10. X ^{i + 1} is the silylalkyl group when i is less than c, and is a hydrogen atom when i = c. b ⁱ is an integer of 0 to 2 when i = 1, and is a number of less than 3 when i is 2 or more, preferably 1 or less, and particularly preferably 0. This is because if a large number of alkoxy groups are present in one molecule of component (B), the flow characteristics and curing characteristics of the silicone rubber composition of the present invention may be deteriorated.

で示され、階層数ｃが２である場合、式（１）のシリルアルキル基は：

で示され、階層数ｃが３である場合、式（１）のシリルアルキル基は：

で示される。（Ｂ）成分一分子中に式（１）で示されるシリルアルキル基が複数存在する場合、式（１）で示されるシリルアルキル基は全て同じでも、異なっていてもよいが、一分子中の式（１）で示されるシリルアルキル基は同じ階層数ｃを有することが好ましい。 When the number of layers c is 1, the silylalkyl group of formula (1) is:

And when the number of layers c is 2, the silylalkyl group of formula (1) is:

And the number of layers c is 3, the silylalkyl group of formula (1) is:

Indicated by (B) When a plurality of silylalkyl groups represented by the formula (1) are present in one molecule of the component, all the silylalkyl groups represented by the formula (1) may be the same or different. The silylalkyl groups represented by formula (1) preferably have the same number of layers c.

As the component (B), a siloxane unit selected from the group consisting of formula: X ¹ R ¹ ₂ SiO _1/2 , formula: X ¹ R ¹ SiO _2/2 , and formula: X ¹ SiO _3/2 Illustrative are organopolysiloxanes containing. In addition to the above siloxane unit, the component (B) is composed of a monofunctional siloxane unit represented by R ¹ ₃ SiO _1/2 (M unit) and a bifunctional siloxane unit represented by R ¹ ₂ SiO _2/2 (D Unit), a trifunctional siloxane unit (T unit) represented by R ¹ SiO _3/2 and a tetrafunctional siloxane unit (Q unit) represented by the formula: SiO _4/2 . R ¹ and X ¹ are the same as described above.

（Ｘ^１Ｒ^１ _２ＳｉＯ_１／２）_ｐ（Ｒ^１ＳｉＯ_３／２）_ｑ
（Ｘ^１ＳｉＯ_３／２）_ｒ
（Ｘ^１Ｒ^１ _２ＳｉＯ_１／２）_ｓ（ＳｉＯ_４／２）_ｔ
で示されるオルガノポリシロキサンが例示される。なお、式中、Ｘ^１，Ｒ^１は前記に同じ、ａは１〜４の整数であり、ｚは３〜２０の整数であり、ｍ，ｎ，ｘ，ｙ，ｐ，ｑ，ｒ，ｓ，ｔは１以上の整数であり、ｐ＋ｑは５以上、ｓ＋ｔは６以上である。 As the component (B), the following formula:

(X ¹ R ¹ ₂ SiO _1/2 ) _p (R ¹ SiO _3/2 ) _q
(X ¹ SiO _3/2 ) _r
(X ¹ R ¹ ₂ SiO _1/2 ) _s (SiO _4/2 ) _t
The organopolysiloxane shown by these is illustrated. In the formula, X ¹ and R ¹ are the same as described above, a is an integer of 1 to 4, z is an integer of 3 to 20, and m, n, x, y, p, q, r, s , T is an integer of 1 or more, p + q is 5 or more, and s + t is 6 or more.

または式：

で示される、シロキサン結合とシルアルキレン結合とが交互に配列したポリカルボシロキサンであることが製造の容易さの点から好ましい。なお、式中ｄは３または４であり、Ｒ^１は前記に同じであり、Ｙ^１はｉ＝１のときの下記式で示されるシリルアルキル基である。

式中、Ｒ^２は前記に同じであり、ｉはＹ^ｉで示されるシリルアルキル基の階層を示し、階層数、すなわち、該シリルアルキル基の繰り返し数は１または２であり、Ｙ^ｉ＋１は、階層数が１のときは水素原子であり、階層数が２のときは、ｉ＝１のとき上記シリルアルキル基であり、ｉ＝２のとき水素原子である。 Among other things, the formula:

Or the formula:

From the viewpoint of ease of production, a polycarbosiloxane in which siloxane bonds and silalkylene bonds are alternately arranged is preferable. In the formula, d is 3 or 4, R ¹ is the same as above, and Y ¹ is a silylalkyl group represented by the following formula when i = 1.

In the formula, R ² is the same as above, i represents the hierarchy of the silylalkyl group represented by Y ⁱ , the number of layers, that is, the number of repetitions of the silylalkyl group is 1 or 2, and Y ^{i + 1} is When the number of layers is 1, it is a hydrogen atom, and when the number of layers is 2, it is the silylalkyl group when i = 1, and is a hydrogen atom when i = 2.

  The component (B) is a single compound or a mixture thereof, but it is preferable that the dispersity index in terms of molecular weight in terms of polystyrene, that is, the quotient of the weight average molecular weight and the number average molecular weight (Mw / Mn) is 2 or less.

Specific examples of the component (B) include polymers represented by the following average molecular formula.

  The amount of component (B) is such that the molar ratio of silicon-bonded hydrogen atoms in this component to alkenyl groups in the silicone rubber composition of the present invention is in the range of 0.01 to 20, preferably The amount is within the range of 0.1 to 10, particularly preferably the amount within the range of 0.1 to 5. This is because, when the blending amount of the component (B) is less than the lower limit of the above range, the resulting silicone rubber composition is not sufficiently cured, the onset of the adhesive force to the silicone rubber is delayed, the adhesion to the silicone rubber This is because the force tends to decrease, and when the upper limit of the above range is exceeded, the mechanical properties of the resulting silicone rubber tend to decrease.

The component (B) can be produced by a conventionally known method, but is preferably produced by the method described in JP-A-10-298288 or JP-A-2000-212283. Specifically, using the silicon atom-bonded hydrogen atom-containing organopolysiloxane as a starting material, the following (X) step and (Y) step are alternately repeated c times to obtain the silylalkyl group of the formula (1) having the number of layers c. The forming method is preferred.
(X): A step of obtaining a silicon atom-bonded alkoxy group-containing siloxane-silalkylene copolymer by addition reaction of silicon-bonded hydrogen atom-containing organopolysiloxane and alkenyltrialkoxysilane in the presence of a hydrosilylation reaction catalyst (Y ): In the presence of an acidic aqueous solution, tetraorganodisiloxane such as 1,1,3,3-tetramethyldisiloxane is added to the silicon-bonded alkoxy group-containing siloxane / silalkylene copolymer obtained in the step (X). A step of reacting and substituting the alkoxy group with a diorganosiloxy group

  The step (Y) is a step in which a silicon atom-bonded alkoxy group-containing siloxane / silalkylene copolymer and tetraorganodisiloxane are reacted in the presence of an alcohol-containing acidic aqueous solution and then treated with a carboxylic acid and a sulfonic acid catalyst. Preferably there is. This is because the remaining alkoxy group is converted into a diorganosiloxy group with high efficiency.

  The organopolysiloxane of component (C) is a curing agent for the silicone rubber composition, and has an average of two or more silicon-bonded hydrogen atoms in one molecule. The molecular structure of the component (C) is not particularly limited, and may be, for example, a linear, branched, cyclic, or three-dimensional network resinous material. However, the above component (B) is excluded. (C) The organic group bonded to the silicon atom in the component includes alkyl groups such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group; phenyl group, tolyl group, xylyl group, etc. Aryl groups; aralkyl groups such as benzyl group and phenethyl group; halogenated alkyl groups such as 3-chloropropyl group and 3,3,3-trifluoropropyl group are exemplified, and a methyl group is preferable. The viscosity at 25 ° C. of such component (C) is not limited, but is preferably in the range of 1 to 1,000,000 mPa · s.

As the component (C), molecular chain both ends trimethylsiloxy group-capped methylhydrogenpolysiloxane, molecular chain both ends trimethylsiloxy-capped dimethylsiloxane / methylhydrogensiloxane copolymer, molecular chain both ends dimethylhydrogensiloxy group-capped dimethyl Polysiloxane, dimethylhydrogensiloxy group-capped methylhydrogen polysiloxane with molecular chain terminals, dimethylhydrogensiloxy-capped dimethylsiloxane / methylhydrogensiloxane copolymer with molecular chain terminals, cyclic methylhydrogenpolysiloxane, formula: (CH _{3) 2} siloxane units of the formula HSiO _1/2: an organopolysiloxane composed of siloxane units represented by _{SiO 4/2,} a portion of the methyl groups of these organopolysiloxanes Or an alkyl group such as an ethyl group and a propyl group; an aryl group such as a phenyl group and a tolyl group; an organopolysiloxane substituted with a halogenated alkyl group such as a 3,3,3-trifluoropropyl group, and these The mixture of 2 or more types of organopolysiloxane is illustrated. In particular, since the component (C) has good mechanical properties and good adhesion to the silicone rubber, the organohydrogenpolysiloxane, diorganosiloxane / organohydrogensiloxane copolymer, or molecular chain It is preferably a diorganopolysiloxane having both ends of a diorganohydrogensiloxy group blocked, a triorganosiloxy group-blocked diorganosiloxane / organohydrogensiloxane copolymer having a molecular chain at both ends, and a diorganohydrogensiloxy group having both ends of a molecular chain. It is more preferable that it is a blocked diorganopolysiloxane, or a mixture thereof, and it is particularly preferable that it is a diorganohydrogensiloxy group blocked diorganopolysiloxane having both molecular chains.

  In the silicone rubber composition of the present invention, the amount of component (C) is such that the molar ratio of silicon atom-bonded hydrogen atoms in this component to alkenyl groups in the silicone rubber composition of the present invention is in the range of 0.01-20. The amount is preferably in the range of 0.1 to 10, and particularly preferably in the range of 0.1 to 5. This is because if the amount of component (C) is less than the lower limit of the above range, the resulting silicone rubber composition tends not to be sufficiently cured, whereas if it exceeds the upper limit of the above range, it is obtained. This is because the mechanical properties of the obtained silicone rubber tend to deteriorate. In the silicone rubber composition of the present invention, both the component (B) and the component (C) act as a curing agent, and their blending amounts are as described above, but preferably, silicon atoms in the component (B) The ratio is such that the ratio of the number of moles of bonded hydrogen atoms to the number of moles of silicon-bonded hydrogen atoms in component (C) is in the range of 1: 1 to 1:10. When the ratio of the number of moles of silicon atom-bonded hydrogen atoms in component (B) to the number of moles of silicon-bonded hydrogen atoms in component (C) is less than the above range, the development of adhesive strength to silicone rubber is delayed. This is because the adhesive strength to the silicone rubber tends to decrease. On the other hand, when the ratio of the number of moles of silicon-bonded hydrogen atoms in component (B) to the number of moles of silicon-bonded hydrogen atoms in component (C) exceeds the above range, the silicone rubber composition of the present invention is cured. This is because the mechanical properties such as elongation of the resulting silicone rubber tend to decrease. The total molar ratio of the silicon atom-bonded hydrogen atom in the component (B) and the silicon atom-bonded hydrogen atom in the component (C) to the alkenyl group in the silicone rubber composition of the present invention is 0.1 to 10. The amount is preferably 0.1 to 5, more preferably 0.5 to 2.0, and particularly preferably 0.5 to 2.0.

Component (D) is a calcium carbonate powder for improving the adhesion of the silicone rubber composition of the present invention to silicone rubber. Although the BET specific surface area of (D) component is not specifically limited, Preferably it is 5-50 m < ² > / g, Most preferably, it is 10-50 m < ² > / g. Such calcium carbonate powder of component (D) includes heavy (or dry pulverized) calcium carbonate powder, light (or precipitated) calcium carbonate powder, and surface of these calcium carbonate powders with organic acids such as fatty acids and resin acids. Examples of the treated powder include light (or precipitated) calcium carbonate powder, and particularly preferred is a light (or precipitated) calcium carbonate powder surface-treated with an organic acid such as a fatty acid or a resin acid.

  In the silicone rubber composition of the present invention, the blending amount of the component (D) is in the range of 1 to 200 parts by mass, preferably in the range of 5 to 200 parts by mass with respect to 100 parts by mass of the component (A). Especially preferably, it exists in the range of 10-100 mass parts. This is because if the blending amount of the component (D) is less than the lower limit of the above range, the adhesiveness of the silicone rubber composition of the present invention to the silicone rubber tends to decrease, whereas it exceeds the upper limit of the above range. This is because it becomes difficult to prepare a uniform silicone rubber composition.

  Component (E) is a hydrosilylation reaction catalyst for promoting the curing of the silicone rubber composition of the present invention. The hydrosilylation catalyst (E) is as follows. Examples of such platinum-based catalysts include platinum fine powder, platinum black, chloroplatinic acid, platinum tetrachloride, chloroplatinic acid alcohol solutions, platinum olefin complexes, platinum alkenylsiloxane complexes, platinum carbonyl complexes, etc. Platinum-based catalyst; Rhodium chloride, rhodium chloride di (n-butyl) sulfide complex Rhodium-based catalyst such as chlorotris (triphenylphosphine) rhodium; palladium supported on carbon, palladium-based catalyst such as palladium chloride; Examples thereof include fine powders obtained by dispersing a catalyst for a chemical reaction in a thermoplastic organic resin such as methyl methacrylate resin, polycarbonate resin, polystyrene resin, or silicone resin.

  In the silicone rubber composition of the present invention, the amount of component (E) is not particularly limited as long as it is an amount that accelerates the curing of the silicone rubber composition of the present invention, but preferably, 1 million parts by mass of the silicone rubber composition of the present invention. The amount of platinum metal in component (D) is in the range of 0.01 to 500 parts by mass, particularly preferably in the range of 0.1 to 100 parts by mass, particularly preferably 5 It is the quantity which becomes in the range of -70 mass parts.

In order to improve the mechanical strength of the silicone rubber obtained by curing, the silicone rubber composition of the present invention may further contain (F) silica powder. Examples of the component (F) include fumed silica, precipitated silica, calcined silica, pulverized quartz, and powder obtained by surface-treating these silica powders with organosilicon compounds such as organoalkoxysilane, organohalosilane, and organosilazane. Is mentioned. In particular, in order to sufficiently improve the mechanical strength of the obtained cured adhesive, it is preferable to use silica powder having a BET specific surface area of 50 m ² / g or more as the component (F).

  In the silicone rubber composition of the present invention, the amount of the component (F) is arbitrary, but in order to improve the mechanical strength of the resulting silicone rubber, 1 to 100 parts by mass with respect to 100 parts by mass of the component (A). It is preferable that it is within the range of 1 to 50 parts by mass.

  The silicone rubber composition of the present invention includes other optional components such as fumed titanium oxide, carbon black, diatomaceous earth, iron oxide, aluminum oxide, aluminosilicate, zinc oxide, aluminum hydroxide, silver, nickel. Inorganic fillers such as: a filler obtained by treating the surface of these fillers with the organosilicon compound may be contained.

  Further, the silicone rubber composition of the present invention has, as an adhesion-imparting agent for improving the adhesion, methyltrimethoxysilane, vinyltrimethoxysilane, allyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3- Such as glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, bis (trimethoxysilyl) propane, bis (trimethoxysilyl) hexane, etc. Silane coupling agents; titanium compounds such as tetraethyl titanate, tetrapropyl titanate, tetrabutyl titanate, tetra (2-ethylhexyl) titanate, titanium ethyl acetonate, titanium acetyl acetonate; ethyl acetoacetate aluminum Aluminum compounds such as diisopropylate, aluminum tris (ethyl acetoacetate), alkyl acetoacetate aluminum diisopropylate, aluminum tris (acetylacetonate), aluminum monoacetylacetonate bis (ethylacetoacetate); zirconium acetylacetonate, zirconium Zirconium compounds such as butoxyacetylacetonate, zirconium bisacetylacetonate and zirconium ethylacetoacetate; alkoxysilyl groups such as 1 to 3 trimethoxysilyl groups are added to the allyl groups of triallyl isocyanurate and triallyl isocyanurate Alkoxysilyl-substituted triallyl isocyanurate and modified siloxane derivatives (derivatives) that are partially hydrolyzed condensates thereof Which triallyl isocyanurate compound may contain. Although the compounding quantity of these adhesion | attachment imparting agents is not limited, Preferably, it exists in the range of 0.01-10 mass parts with respect to 100 mass parts of (A) component.

  Furthermore, the silicone rubber composition of the present invention has 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyne-3 in order to improve its storage stability and handling workability. Acetylene compounds such as -ol, 2-phenyl-3-butyn-2-ol, 1-ethynylcyclohexane-1-ol; 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexene Ene-in compounds such as -1-yne; 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5 , 7-tetrahexenyl cyclotetrasiloxane, silanol group-blocked methyl vinyl siloxane with both molecular chains, silanol group-blocked methyl vinyl siloxane / dimethyl siloxane copolymer with both molecular chains Organosiloxane compound having a vinyl group 5 wt% or more in one molecule; triazoles such as benzotriazole, phosphines, mercaptans, preferably contains a curing inhibitor such as hydrazines. Although the compounding quantity of these hardening inhibitors is not limited, It is preferable to exist in the range of 0.001-5 mass parts with respect to 100 mass parts of (A) component.

  The method for preparing the silicone rubber composition of the present invention is not limited, and it can be prepared by mixing the (A) component to the (E) component and, if necessary, the (F) component and other optional components. When this invention silicone rubber composition contains (F) component, it is preferable to mix | blend (B) component-(E) component, after previously heat-mixing (A) component and (F) component. Moreover, when (A) component and (F) component are heat-mixed, the said organosilicon compound may be added and the surface of (F) component may be processed in-situ. The silicone rubber composition of the present invention can be prepared using a known kneading apparatus such as a two-roll roll, a kneader mixer, or a loss mixer.

  Moreover, the silicone rubber composition of the present invention comprises the composition (I) containing the component (A) and the component (E) and not containing the components (B) and (C), the component (A), From the viewpoint of storage stability, it is a two-component silicone rubber composition comprising the component (B) and the composition (II) containing the component (C) and not the component (E). preferable. The component (D) may be contained in one or both of the composition (I) and the composition (II), but the fluidity of the composition (I) and the composition (II). In addition, since the difference in density is preferably small, it is preferable that both the composition (I) and the composition (II) contain the component (D). When the component (F) is included, it is preferably blended with the composition (I) and / or the composition (II) as a mixture preliminarily heated and mixed with the component (A).

  The silicone rubber composition of the present invention will be described in detail with reference to examples and comparative examples. In addition, the viscosity in an Example is a value in 25 degreeC, and the characteristic of silicone rubber is the value measured as follows.

[Physical properties of silicone rubber]
Silicone rubber was produced by allowing the silicone rubber composition to stand at 25 ° C. for 24 hours. The hardness of the silicone rubber was measured with a type A durometer specified in JIS K 6253-1997. Further, the silicone rubber composition was allowed to stand at 25 ° C. for 2 hours and 24 hours, whereby a test piece having a shape conforming to the dumbbell shape No. 7 defined in JIS K 6251-1993 “Tensile test method for vulcanized rubber” A dumbbell-shaped test piece having a wide grip portion was produced. The tensile strength and elongation of this dumbbell-shaped test piece were measured by the method prescribed in JIS K 6251-1993.
[Adhesive strength to silicone rubber]
The adhesion of the silicone rubber composition to the silicone rubber was measured as follows according to the method specified in JIS K6854. That is, the silicone rubber composition was applied onto a 50 mm wide silicone rubber-coated nylon tape, and the silicone rubber-coated nylon tape was bonded to the composition so that the thickness of the composition was 1.0 mm. The composition was cured by allowing it to stand for 24 hours to prepare a test piece. Next, the silicone rubber-coated nylon tape was subjected to a T-type peel test at a tensile speed of 200 mm / min, thereby measuring the adhesive force to the silicone rubber.

で表されるケイ素原子結合メトキシ基含有シロキサン・シルアルキレン共重合体であることが判明した。 [Reference Example 1]
Into a 300 ml four-necked flask equipped with a stirrer, thermometer, reflux condenser, and dropping funnel, 107.9 g of vinyltrimethoxysilane and 0.02 g of 3% isopropanol solution of chloroplatinic acid were added and stirred at 100 ° C. Heated. Next, 80.0 g of tetrakis (dimethylsiloxy) silane was slowly added dropwise thereto so that the reaction temperature was kept at 100 to 110 ° C. using a dropping funnel. After completion of the dropwise addition, the reaction solution was heated at 120 ° C. for 1 hour. After cooling, the reaction solution was transferred to a mold flask and concentrated under reduced pressure using a rotary evaporator. As a result, 166.9 g of a slightly brown liquid was obtained. When the obtained liquid is analyzed, this liquid has the formula:

It was found that the siloxane-silalkylene copolymer containing a silicon atom-bonded methoxy group represented by

で表されるケイ素原子結合メトキシ基含有シロキサン・シルアルキレン共重合体 ２２２．６ｇを滴下ロートを用いて１時間かけて滴下した。滴下終了後、反応溶液を１時間攪拌した。次いでこの反応溶液を分液ロートに移して下層を分取し、残った上層を水 ２００ｍｌで３回洗浄して、塩化カルシウムで乾燥した。生成した固形分を濾過した後、酢酸２１０ｇおよびトリフルオロメタンスルホン酸 ０．８６ｍｇを加えて５０℃に昇温し、１時間反応させた。反応終了後、反応溶液を滴下ロートに移して下層を分取した後、水 ２００ｍｌで３回、飽和炭酸ナトリウム水溶液 ２００ｍｌで１回洗浄し、次いで塩化カルシウムで乾燥した。生成した固形分を濾過して得られた反応溶液を減圧濃縮したところ、３４２．４ｇの無色透明液体が得られた。得られた液体を^２９Ｓｉ−核磁気共鳴分析により分析したところ、この液体は、平均分子式：

で示される、一分子中に１２個のケイ素原子結合水素原子を含有するケイ素原子結合水素原子含有シロキサン・シルアルキレン共重合体（以下、ケイ素原子結合水素原子含有ポリカルボシロキサンという。）であることが判明した。このケイ素原子結合水素原子含有ポリカルボシロキサンは、ゲル透過クロマトグラフィーによるポリスチレン換算数平均分子量が１８６６であり、分散度指数が１．１９であった。 Next, in a 1000 ml four-necked flask equipped with a stirrer, thermometer, reflux condenser and dropping funnel, 235.4 g of 1,1,3,3-tetramethyldisiloxane, 74 ml of concentrated hydrochloric acid, 148 ml of water and isopropanol 148 ml was added and stirred. To this, under the temperature conditions of 25-30 ° C., the formula obtained above:

222.6 g of a silicon atom-bonded methoxy group-containing siloxane / silalkylene copolymer represented by the formula (1) was added dropwise using a dropping funnel over 1 hour. After completion of the dropwise addition, the reaction solution was stirred for 1 hour. The reaction solution was then transferred to a separatory funnel to separate the lower layer, and the remaining upper layer was washed with 200 ml of water three times and dried over calcium chloride. After the produced solid content was filtered, 210 g of acetic acid and 0.86 mg of trifluoromethanesulfonic acid were added, and the temperature was raised to 50 ° C. and reacted for 1 hour. After completion of the reaction, the reaction solution was transferred to a dropping funnel, and the lower layer was separated, washed 3 times with 200 ml of water and once with 200 ml of a saturated aqueous sodium carbonate solution, and then dried over calcium chloride. When the reaction solution obtained by filtering the produced solid content was concentrated under reduced pressure, 342.4 g of a colorless transparent liquid was obtained. The obtained liquid was analyzed by ²⁹ Si-nuclear magnetic resonance analysis. The liquid was found to have an average molecular formula:

A silicon atom-bonded hydrogen atom-containing siloxane / silalkylene copolymer (hereinafter referred to as silicon-bonded hydrogen atom-containing polycarbosiloxane) having 12 silicon atom-bonded hydrogen atoms in one molecule. There was found. This silicon-bonded hydrogen atom-containing polycarbosiloxane had a polystyrene-reduced number average molecular weight of 1866 by gel permeation chromatography and a dispersity index of 1.19.

[Example 1]
100 parts by mass of dimethylpolysiloxane blocked with a dimethylvinylsiloxy group at both ends of a molecular chain having a viscosity of 40,000 mPa · s, 15 parts by mass of fumed silica having a BET specific surface area of 200 m ² / g, hexamethyldisilazane 1 Then, 5 parts by mass and 1 part by mass of water were uniformly mixed and then heated and mixed at 170 ° C. for 2 hours under reduced pressure to obtain a dimethylpolysiloxane / fumed silica mixture blocked with dimethylvinylsiloxy group-blocked dimethylvinylsiloxy groups.

で表されるケイ素原子結合水素原子含有ポリカルボシロキサン ０．１５質量部（本シリコーンゴム組成物中中のビニル基に対する本成分中のケイ素原子結合水素原子のモル比が０．２７となる量）、粘度９．５ｍＰａ・ｓの分子鎖両末端ジメチルハイドロジェンシロキシ基封鎖ジメチルポリシロキサン ２．１１質量部（本シリコーンゴム組成物中のビニル基に対する本成分中のケイ素原子結合水素原子のモル比が０．６３となる量）、および白金の１，３−ジビニルテトラメチルジシロキサン錯体の１，３−ジビニルテトラメチルジシロキサン溶液（本シリコーンゴム組成物 １００万質量部に対して本触媒中の白金金属が４５質量部となる量）を混合してシリコーンゴム組成物を調製した。このシリコーンゴム組成物を硬化して得られるシリコーンゴムの物理特性および接着力を測定し、それらの結果を表１に示した。 40.7 parts by mass of the above mixture, 40 parts by mass of precipitated calcium carbonate powder having a BET specific surface area of 18 m ² / g treated with a fatty acid (white glazed CCR manufactured by Shiroishi Kogyo Co., Ltd.) and a viscosity of 40,000 mPa · s 70.3 parts by mass of dimethylpolysiloxane blocked with dimethylvinylsiloxy group at both ends of the molecular chain, average composition formula obtained in Reference Example 1:

0.15 parts by mass of a polycarbosiloxane containing silicon atom-bonded hydrogen atoms represented by the formula (amount in which the molar ratio of silicon-bonded hydrogen atoms in this component to vinyl groups in this silicone rubber composition is 0.27) 21.1 parts by weight of dimethylpolysiloxane blocked with a dimethylhydrogensiloxy group at both ends of a molecular chain having a viscosity of 9.5 mPa · s (the molar ratio of silicon-bonded hydrogen atoms in this component to vinyl groups in this silicone rubber composition is 0.63), and 1,3-divinyltetramethyldisiloxane solution of 1,3-divinyltetramethyldisiloxane complex of platinum (the platinum in the catalyst with respect to 1 million parts by mass of the silicone rubber composition) A silicone rubber composition was prepared by mixing 45 parts by mass of metal. The physical properties and adhesive strength of the silicone rubber obtained by curing this silicone rubber composition were measured, and the results are shown in Table 1.

[Example 2]
In Example 1, the compounding amount of the silicon-bonded hydrogen atom-containing polycarbosiloxane obtained in Reference Example 1 was 0.13 parts by mass (the silicon-bonded hydrogen atoms in this component relative to the vinyl groups in the silicone rubber composition) The amount of the dimethylhydrogensiloxy group-capped dimethylpolysiloxane having a viscosity of 9.5 mPa · s and a viscosity of 9.5 mPa · s is 1.74 parts by mass (vinyl in the silicone rubber composition). The amount of silicon atom-bonded hydrogen atoms in this component relative to the group is 0.63), and the amount of 1,3-divinyltetramethyldisiloxane solution of 1,3-divinyltetramethyldisiloxane complex of platinum In the same manner as in Example 1, except that the amount of platinum metal in the catalyst was changed to 22 parts by mass with respect to 1 million parts by mass of the silicone rubber composition. A corn rubber composition was prepared. The physical properties and adhesive strength of the silicone rubber obtained by curing this silicone rubber composition were measured, and the results are shown in Table 1.

[Comparative Example 1]
In Example 1, instead of the silicon-bonded hydrogen atom-containing polycarbosiloxane obtained in Reference Example 1, a dimethylsiloxane / methylhydrogensiloxane copolymer blocked with a trimethylsiloxy group-blocked trimethylsiloxy group having a viscosity of 13 mPa · s (one molecule) 0.7 parts by mass (in which the molar ratio of silicon atom hydrogen atoms in this component to vinyl groups in this silicone rubber composition is 0.27) A silicone rubber composition was prepared in the same manner as in Example 1 except that was used. The physical properties and adhesive strength of the silicone rubber obtained by curing this silicone rubber composition were measured, and the results are shown in Table 1.

[Comparative Example 2]
In Example 2, instead of the silicon-bonded hydrogen atom-containing polycarbosiloxane obtained in Reference Example 1, a molecular chain-terminated trimethylsiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer having a viscosity of 13 mPa · s (one molecule) 0.7 parts by mass (in which the molar ratio of silicon atom hydrogen atoms in this component to vinyl groups in this silicone rubber composition is 0.27) A silicone rubber composition was prepared in the same manner as in Example 1 except that was used. The physical properties and adhesive strength of the silicone rubber obtained by curing this silicone rubber composition were measured, and the results are shown in Table 1.

  The silicone rubber composition of the present invention has a rapid onset of adhesion to silicone rubber and has excellent adhesion to silicone rubber. Therefore, when used as an adhesive for silicone rubber made of cured silicone rubber, It is preferable because the time required for the manufacturing process can be shortened and the adhesion is strong. More specifically, for example, in an airbag formed into a bag shape by superimposing the coated surfaces of a base fabric impregnated and / or coated with silicone rubber and bonding or sewing the peripheral edges thereof, the base fabric It is suitable as an adhesive or a sealant at the place where they are overlapped and bonded or sewn. Further, for example, it is suitable as an adhesive for vibration-proof members and impact-absorbing members made of a laminate of silicone gel or silicone rubber. For example, it is suitable as a surface treatment agent for the purpose of maintaining the shape of the silicone gel, protecting the surface or reinforcing it.

Claims (9)

(A) Diorganopolysiloxane having an average of at least two alkenyl groups in one molecule
100 parts by mass,
(B) X ¹ bonded to a silicon atom {silylalkyl group represented by the following formula (1) when i = 1:

(In the formula, R ¹ is an alkyl group having 1 to 10 carbon atoms or an aryl group, R ² is an alkylene group having 2 to 10 carbon atoms, and R ³ is an alkyl group having 1 to 10 carbon atoms. There, i is the generation of a silylalkyl group represented by X ^i, an integer 1~c when the generation number c, the number of layers c is an integer of from 1 to 10, b ⁱ is i = 1 Is an integer from 0 to 2, when i is 2 or more, it is a number less than 3, X ^{i + 1} is the silylalkyl group when i is less than c, and when i = c is a hydrogen atom )} In one molecule and having an average of 3 or more silicon-bonded hydrogen atoms in one molecule {bonding of silicon atoms in this component to alkenyl groups in the composition The amount by which the molar ratio of hydrogen atoms is 0.01-20},
(C) Organopolysiloxane having an average of at least two silicon-bonded hydrogen atoms in one molecule {however, component (B) is excluded. } {Amount in which the molar ratio of silicon-bonded hydrogen atoms in this component to alkenyl groups in this composition is 0.01 to 20}
(D) 1 to 200 parts by mass of calcium carbonate powder, and (E) a catalyst for hydrosilylation reaction (amount that promotes curing of the composition)
A silicone rubber composition comprising at least (B) component is a formula:

Or the formula:

{Wherein d is 3 or 4, R ¹ is an alkyl group or aryl group having 1 to 10 carbon atoms, and Y ¹ is a silylalkyl group represented by the following formula when i = 1:

(Wherein R ¹ is the same as above, R ² is an alkylene group having 2 to 10 carbon atoms, i represents a hierarchy of the silylalkyl group represented by Y ⁱ , and the hierarchy number c is 1 or 2) Y ^{i + 1} is a hydrogen atom when the hierarchy number c is 1, and when the hierarchy number c is 2, it is the silylalkyl group when i = 1, and is a hydrogen atom when i = 2. The silicone rubber composition according to claim 1, which is a polycarbosiloxane represented by the following formula: The ratio of the number of moles of silicon-bonded hydrogen atoms in component (B) to the number of moles of silicon-bonded hydrogen atoms in component (C) is 1: 1 to 1:10, and the alkenyl group in the composition The total molar ratio of the silicon atom-bonded hydrogen atom in the component (B) to the silicon atom-bonded hydrogen atom in the component (C) is 0.1-10. Or the silicone rubber composition of Claim 2. The silicone rubber composition according to claim 1 or 2, wherein the component (D) is a light (or precipitated) calcium carbonate powder. Furthermore, (F) Silica powder {1-100 mass parts with respect to 100 mass parts of (A) component} is contained, The silicone rubber composition of Claim 1 or Claim 2 characterized by the above-mentioned. The organo (C) component is selected from the group consisting of organohydrogenpolysiloxanes, diorganosiloxane / organohydrogensiloxane copolymers, diorganohydrogensiloxy group-blocked diorganopolysiloxanes with both molecular chains, and mixtures thereof. The silicone rubber composition according to claim 1, wherein the silicone rubber composition is polysiloxane. It is an adhesive for silicone rubber, The silicone rubber composition of any one of Claims 1-6 characterized by the above-mentioned. The silicone rubber composition according to any one of claims 1 to 6, wherein the silicone rubber composition is an adhesive for a silicone rubber coated fabric. The silicone rubber composition according to any one of claims 1 to 6, wherein the silicone rubber composition is a sealing agent for a silicone rubber coated fabric.