JP2020094139A - Antistatic silicone rubber composition and antistatic carrier plate - Google Patents

Abstract

To provide an antistatic silicone rubber composition which becomes a silicone rubber cured product that can maintain excellent antistatic properties even when exposed to a high temperature.SOLUTION: The antistatic silicone rubber composition is obtained by blending a base composition, which contains a base compound containing an organopolysiloxane having two or more alkenyl groups bonded to a silicon atom in one molecule and a curing agent and gives an insulating silicone rubber cured product by thermal curing, with 0.001-5 pts.mass of an ionic liquid having at least one polymerizable reactive group in one molecule and containing a phosphonium type cation and a fluorine-containing anion based on 100 pts.mass of the base compound.SELECTED DRAWING: None

Description

The present invention relates to an antistatic silicone rubber composition, which has a sufficient antistatic property not only at room temperature but also at high temperature, and also has excellent bleeding properties, and provides a silicone rubber cured product which does not easily turn yellow. -Resistant silicone rubber composition and antistatic carrier plate.

Silicone rubber has excellent weather resistance, electrical characteristics, low compression set, heat resistance, cold resistance, etc., and is used in various fields including electrical equipment, automobiles, construction, medical care, and food. Widely used. For example, keypads used as rubber contacts for remote controllers, typewriters, word processors, computer terminals, musical instruments, etc., building gaskets, anti-vibration rubber for audio equipment, connector seals, automobile parts such as spark plug boots, computers, etc. Examples include packings for compact discs used, molds for bread, cakes, and the like. Currently, the demand for silicone rubber is increasing more and more, and development of silicone rubber having excellent properties is desired.

These silicone rubbers (cured products) are generally supplied in the form of a composition containing a high degree of polymerization organopolysiloxane and a reinforcing filler. This composition is prepared by mixing the raw material polymer with the reinforcing filler and various dispersants using a mixing device such as a dough mixer or a two-roll mill. Reinforcing fillers such as organopolysiloxane and silica are electrical insulating materials, and the silicone rubber composition obtained by blending them and the cured silicone rubber are charged by contact with various substances, resulting in static electricity. There are problems such as occurrence of dust and adsorption of dust in the air.

Conventionally, an antistatic rubber has been used as an antistatic agent, such as a polyether-based ion conductive polymer such as a polyether ester amide (Japanese Patent Publication No. 2002-500237 (Patent Document 1)) and carbon black (Japanese Patent Publication No. 2002-507240 ( Patent Document 2)), a polymer solid electrolyte such as polyether ester amide, and a conductive material such as zinc oxide (Japanese Patent Laid-Open No. 2002-327122 (Patent Document 3)).

However, when the polyether ion conductive polymer (polymer solid electrolyte) is blended, there is a problem that the polymer is decomposed at high temperature and a sufficient antistatic effect is not exhibited. In particular, the actual situation is that the antistatic effect is almost lost even by performing known post-cure with a thermosetting silicone rubber. In addition, when carbon black (conductive material) is blended, there is a problem that it is difficult to maintain electrical insulation or the color is limited to black.

Further, Japanese Patent Application Laid-Open No. 2003-82232 (Patent Document 4) proposes a silicone rubber composition for a semiconductive roller to which a lithium salt is added, but in the semiconductive region, an electric wire that cannot be used unless it is an insulating substance However, there was a problem that it could not be applied to the coating and keypad.

Japanese Patent No. 5916457 (Patent Document 5) and Japanese Patent No. 6177430 (Patent Document 6) propose a silicone rubber containing an ionic liquid having an alkoxysilyl group, but when the cured product is left at high temperature. There was a problem that the ionic liquid bleeds.

Tokuyo 2002-500237 Special table 2002-507240 gazette JP, 2002-327122, A JP, 2003-82232, A Patent No. 5916457 Japanese Patent No. 6177430 JP, 2006-344826, A

The present invention has been made in view of the above circumstances, and an antistatic silicone rubber composition and a cured product thereof, which become a silicone rubber cured product capable of maintaining excellent antistatic properties not only at room temperature but also at high temperatures. An object of the present invention is to provide an antistatic carrier plate using.

As a result of intensive studies to achieve the above-mentioned objects, the inventors of the present invention have achieved the above problems by adding a small amount of a specific ionic liquid as an ionic conductive antistatic agent to a thermosetting silicone rubber composition base. The inventors have found that they can be solved, and further studied to complete the present invention.

（式中、Ｙは重合性反応基であり、Ｚは単結合又はオルガノポリシロキサン構造を含む２〜２０価の基であり、Ｒ³は互いに独立して単結合、又は非置換若しくは置換の炭素数１〜２０の２価炭化水素基であり、Ｒ⁴、Ｒ⁵及びＲ⁶はそれぞれ互いに独立して非置換若しくは置換の炭素数１〜１０のアルキル基、又は炭素数６〜１０のアリール基である。また、ｒは１〜１０の整数、ｓは１〜１０の整数であり、かつｒ＋ｓがＺの価数に対応する２〜２０の整数である。）
６．
上記重合性反応基が、ビニル基、ビニルオキシ基、アクリロキシ基、（メタ）アクリルオキシ基、（メタ）アクリルアミド基、スチリル基又はスチリルオキシ基である１〜５のいずれかに記載の帯電防止性シリコーンゴム組成物。
７．
上記硬化剤がオルガノハイドロジェンポリシロキサンとヒドロシリル化触媒との組み合わせからなる請求項１〜６のいずれかに記載の帯電防止性シリコーンゴム組成物。
８．
上記硬化剤が有機過酸化物からなる請求項１〜６のいずれかに記載の帯電防止性シリコーンゴム組成物。
９．
６ｋＶの静電気をチャージした後、その帯電圧が３ｋＶになる半減期が２分以内の帯電防止能を有するシリコーンゴム硬化物を与えるものである１〜８のいずれかに記載の帯電防止性シリコーンゴム組成物。
１０．
１〜９のいずれかに記載の帯電防止性シリコーンゴム組成物を硬化してなるシリコーンゴム硬化物を使用した帯電防止キャリアプレート。 That is, the present invention provides the following antistatic silicone rubber composition and antistatic carrier plate.
1.
A base composition containing a base compound containing an organopolysiloxane having two or more alkenyl groups bonded to a silicon atom in one molecule and a curing agent, which gives an insulating silicone rubber cured product by heat curing, at least in one molecule. Antistatic silicone rubber composition comprising one polymerizable reactive group and 0.001 to 5 parts by mass of an ionic liquid containing a phosphonium type cation and a fluorine-containing anion with respect to 100 parts by mass of the base compound. Stuff.
2.
The above-mentioned base compound has (A) a degree of polymerization of 100 or more, an organopolysiloxane having two or more alkenyl groups bonded to a silicon atom in one molecule: 100 parts by mass, and (B) a specific surface area by the BET method. Reinforcing silica having 50 m ² /g or more: The antistatic silicone rubber composition according to 1, which contains 10 to 100 parts by mass.
3.
3. The antistatic silicone rubber composition according to 1 or 2, wherein the phosphonium type cation contains an organopolysiloxane structure having a polymerizable reactive group.
4.
The antistatic silicone rubber composition according to any one of 1 to 3, wherein the fluorine-containing anion is a trifluoromethanesulfonate anion, a bis(trifluoromethanesulfonyl)imide anion, a tetrafluoroborate anion or a hexafluorophosphate anion.
5.
The antistatic silicone rubber composition according to any one of 1 to 4, wherein the ionic liquid is an ionic liquid represented by the following formula (3).

(In the formula, Y is a polymerizable reactive group, Z is a single bond or a divalent to 20-valent group containing an organopolysiloxane structure, R ³ is independently a single bond, or an unsubstituted or substituted carbon atom. A divalent hydrocarbon group having 1 to 20 carbon atoms, wherein R ⁴ , R ⁵ and R ⁶ are independently of each other an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. In addition, r is an integer of 1 to 10, s is an integer of 1 to 10, and r+s is an integer of 2 to 20 corresponding to the valence of Z.)
6.
The antistatic silicone according to any one of 1 to 5, wherein the polymerizable reactive group is a vinyl group, a vinyloxy group, an acryloxy group, a (meth)acryloxy group, a (meth)acrylamide group, a styryl group or a styryloxy group. Rubber composition.
7.
The antistatic silicone rubber composition according to any one of claims 1 to 6, wherein the curing agent is a combination of an organohydrogenpolysiloxane and a hydrosilylation catalyst.
8.
The antistatic silicone rubber composition according to claim 1, wherein the curing agent is an organic peroxide.
9.
The antistatic silicone rubber according to any one of 1 to 8, which gives a silicone rubber cured product having an antistatic ability with a half-life of 2 kV or less after charging a static electricity of 6 kV to 3 kV. Composition.
10.
An antistatic carrier plate using a silicone rubber cured product obtained by curing the antistatic silicone rubber composition according to any one of 1 to 9.

According to the present invention, it is possible to obtain a cured silicone rubber product that maintains insulation and is excellent in antistatic properties and has little bleeding even when exposed to high temperatures. In addition, since yellowing at high temperature is suppressed, coloring can be freely performed.

Hereinafter, the present invention will be described in detail.
The antistatic silicone rubber composition according to the present invention comprises a base compound containing an organopolysiloxane having two or more alkenyl groups bonded to a silicon atom in one molecule and a curing agent, and cured by heat to produce an insulating silicone rubber. An ionic liquid having at least one polymerizable reactive group in one molecule and containing a phosphonium-type cation and a fluorine-containing anion is added to the base composition giving the product in an amount of 0.001 to 5 with respect to 100 parts by mass of the base compound. It is a mixture of parts by mass.

Here, the base compound is
(A) Organopolysiloxane having a degree of polymerization of 100 or more and having two or more alkenyl groups bonded to silicon atoms in one molecule: 100 parts by mass, and (B) a specific surface area by BET method of 50 m ² /g. It is preferable that the above-mentioned reinforcing silica is contained in an amount of 10 to 100 parts by mass.
Hereinafter, each component in the antistatic silicone rubber composition according to the present invention will be described.

[(A) alkenyl group-containing organopolysiloxane]
The component (A) is a main agent (base polymer) contained in the base compound, and is represented by the following average composition formula (1). The organopolysiloxane has two or more alkenyl groups bonded to a silicon atom in one molecule. Is.
R ¹ _a SiO _(4-a)/2 (1)
(Wherein, R ¹ independently of one another, is a monovalent hydrocarbon radical unsubstituted or substituted, a is a positive number of 1.95 to 2.04. However, among the R ¹ in one molecule Two or more are alkenyl groups.)

In the average composition formula (1), R ¹ is usually a monovalent hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 8 carbon atoms. Specifically, a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an alkyl group such as an octyl group, a cyclopentyl group, a cycloalkyl group such as a cyclohexyl group, a vinyl group, an allyl group, a butenyl group, a hexenyl group, etc. Alkenyl group, cycloalkenyl group, phenyl group, aryl group such as tolyl group, aralkyl group such as β-phenylpropyl group, or part or all of the hydrogen atoms bonded to carbon atoms of these groups are halogen atoms or cyano groups. Examples thereof include a chloromethyl group substituted with a group, a trifluoropropyl group, a cyanoethyl group, and the like. Among these, a methyl group, a vinyl group, a phenyl group and a trifluoropropyl group are preferable, and a methyl group and a vinyl group are more preferable. Of these, in particular, 50 mol% or more of the monovalent hydrocarbon groups represented by R ¹ in the molecule are preferably methyl groups, more preferably 80 mol% or more are methyl groups, and alkenyl It is further preferred that all R ^{1 s} other than the groups are methyl groups.

In the above formula (1), a is a positive number of 1.95 to 2.04, preferably 1.98 to 2.02. If this a value is not within the range of 1.95 to 2.04, the obtained silicone rubber cured product may not exhibit sufficient rubber elasticity.

Further, the organopolysiloxane as the component (A) needs to have at least two alkenyl groups in one molecule, and in the above formula (1), a group bonded to a silicon atom (that is, the above average composition formula). (1) of R ¹⁾ in 0.001 to 10 mol%, and particularly preferably 0.01 to 5 mol% is an alkenyl group. The alkenyl group is preferably a vinyl group or an allyl group, and particularly preferably a vinyl group.

The degree of polymerization of the organopolysiloxane (A) is usually 100 to 50,000, preferably 150 to 20,000. If the degree of polymerization is less than 100, sufficient rubber strength cannot be obtained. The degree of polymerization is obtained as a polystyrene-equivalent weight average degree of polymerization in GPC (gel permeation chromatography) analysis.

The weight average degree of polymerization referred to in the present invention means the weight average degree of polymerization using polystyrene as a standard substance by gel permeation chromatography (GPC) measured under the following conditions.
[Measurement condition]
・Developing solvent: Toluene ・Flow rate: 1 mL/min
・Detector: Differential refractive index detector (RI)
-Column: KF-805L x 2 (manufactured by Shodex)
・Column temperature: 25℃
・Sample injection volume: 30 μL (toluene solution with a concentration of 0.2 mass%)

The organopolysiloxane as the component (A) is not particularly limited as long as it satisfies the above conditions. Usually, the main chain is composed of repeating diorganosiloxane units (R ¹ ₂ SiO _2/2 , R ¹ is the same as above, the same applies hereinafter), and both ends of the molecular chain are triorganosiloxy groups (R ¹ ₃ SiO _1/ It is preferably a linear diorganopolysiloxane blocked with ₂ ), and both ends of the molecular chain are trimethylsiloxy group, dimethylvinylsiloxy group, dimethylhydroxysiloxy group, methyldivinylsiloxy group, trivinylsiloxy group. Those blocked with, etc. are preferable. In particular, a siloxy group having at least one vinyl group, preferably having both molecular chain ends blocked, is suitable. The molecular structure of the organopolysiloxane is not limited and may be basically linear, but may be branched as long as rubber elasticity is not impaired.
These organopolysiloxanes may be used alone or in combination of two or more having different degrees of polymerization and different molecular structures.

Such an organopolysiloxane of the component (A) can be obtained by a known method, for example, by (co)hydrolyzing and condensing one or more kinds of organohalogenosilane, or by using a cyclic polysiloxane with an alkaline or acidic catalyst. It can be obtained by ring-opening polymerization.

[(B) Reinforcing silica]
The reinforcing silica as the component (B) is contained in the base compound, and acts as a component that imparts excellent mechanical properties to the obtained silicone rubber cured product. The reinforcing silica may be precipitated silica (wet silica) or fumed silica (dry silica), and has many silanol groups (SiOH) on the surface.

In the present invention, the specific surface area of the reinforcing silica as the component (B) by the BET method is required to be 50 m ² /g or more, and preferably 100 to 400 m ² /g. If the specific surface area is less than 50 m ² /g, the reinforcing effect of the component (B) may be insufficient.

The reinforcing silica as the component (B) is surface-treated with an organosilicon compound (silica surface treating agent) such as organopolysiloxane, organopolysilazane, chlorosilane, or alkoxysilane, if necessary, even if it is used in an untreated state ( Specifically, it may be subjected to a hydrophobic treatment). It is preferable to use a hydrophobic silica-treated reinforcing silica in terms of dispersibility in the component (A) and reinforcing property. At this time, it is possible to use a powder whose surface has been directly subjected to a hydrophobic treatment with a silica surface treating agent in a powder state, or to add a silica surface treating agent when mixing the fine silica powder and the component (A). The surface may be hydrophobized by heating and mixing.

Such a silica surface treating agent is included in the above base compound, and specifically, chlorosilanes such as trimethylchlorosilane, dimethyldichlorosilane, and methyltrichlorosilane, or hexamethyldisilazane, 1,3-divinyl. Known treating agents such as silazanes such as -1,1,3,3-tetramethyldisilazane can be mentioned. The amount of the silica surface treating agent used is 5 to 75 parts by mass, preferably 5 to 60 parts by mass, relative to 100 parts by mass of the surface-untreated silica fine powder.
The reinforcing silica may be used singly or in combination of two or more.

The amount of the reinforcing silica as the component (B) is 10 to 100 parts by mass, preferably 10 to 80 parts by mass, and more preferably 20 to 100 parts by mass with respect to 100 parts by mass of the organopolysiloxane as the component (A). 70 parts by mass. If the blending amount deviates from the above range, not only the processability of the obtained silicone rubber composition is deteriorated, but also the silicone rubber cured product obtained by curing the silicone rubber composition has mechanical properties such as tensile strength and tear strength. There is a risk that the physical properties will be insufficient.

[Dispersant: organosilane/organosiloxane compound]
In addition to the above components, the base compound preferably contains an organosilane or organosiloxane compound represented by the following general formula as an optional component. This component acts as a dispersant (wetting agent) for improving the dispersibility of the reinforcing silica of the component (B) in the component (A), and by blending this component, The workability and extrusion characteristics of the silicone rubber composition are improved.

R ¹¹ O(Si(R ¹² ) ₂ O) _m R ¹¹
(In the formula, R ¹¹ is a hydrogen atom or the same or different, unsubstituted or substituted alkyl group, R ¹² is the same or different, unsubstituted or substituted monovalent hydrocarbon group, and m is 1 to 50. Is a positive number.)

Here, R ¹¹ is a hydrogen atom or the same or different alkyl group, and the organosilane or siloxane represented by the above general formula has an alkoxy group or a hydroxyl group at the molecular chain terminal. Examples of R ¹¹ include a hydrogen atom or an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, and a hydrogen atom, a methyl group and an ethyl group are preferable. R ¹² is usually preferably a monovalent hydrocarbon group having 1 to 12 carbon atoms, particularly 1 to 8 carbon atoms, specifically, an alkyl group such as a methyl group, an ethyl group, a propyl group or a butyl group, a cyclohexyl group. Groups such as cycloalkyl groups, vinyl groups, allyl groups, butenyl groups, alkenyl groups such as hexenyl groups, phenyl groups, aryl groups such as tolyl groups, aralkyl groups such as β-phenylpropyl groups, or carbon atoms of these groups Is a group in which a part or all of the hydrogen atoms bonded to are substituted with a halogen atom, a cyano group or the like, and examples thereof include a chloromethyl group, a trifluoropropyl group, a cyanoethyl group and the like. In the above examples, a methyl group, a vinyl group, a phenyl group and a trifluoropropyl group are preferable, and a methyl group, a vinyl group and a trifluoropropyl group are particularly preferable.

m is a positive number of 1 to 50, preferably 1 to 30 and more preferably 1 to 20. When m is 50 or less, a sufficient addition effect can be obtained without compounding in a large amount, so that there is no fear of deterioration of rubber physical properties due to compounding in a large amount.

When the present component is blended, the addition amount of the organosilane/siloxane of this component is preferably 0.1 to 50 parts by mass, and 0.5 to 30 parts by mass, relative to 100 parts by mass of the organopolysiloxane of component (A). The mass part is more preferable. If the amount is 0.1 parts by mass or more, the workability, extrusion characteristics, and the like of the silicone rubber composition of the present invention will be sufficiently obtained, and if the amount is 50 parts by mass or less, tackiness will occur in the obtained silicone rubber composition. Since there is no fear, there is no fear that the workability will be deteriorated or the physical properties of the obtained rubber will be deteriorated.

[(C) Curing agent]
The curing agent as the component (C) is not particularly limited as long as it can cure the silicone rubber composition of the present invention. For example, the following (C-1) addition reaction curing agent and/or ( C-2) Organic peroxide curing agents are mentioned. That is, these curing agents react with the organopolysiloxane of the component (A) to form a crosslinked structure in the silicone rubber composition of the present invention to give a cured silicone rubber product.

(C-1) Addition Reaction Curing Agent As the addition reaction curing agent, an organohydrogenpolysiloxane and a hydrosilylation catalyst can be used in combination.

The organohydrogenpolysiloxane has 2 or more, preferably 3 or more, more preferably 3 to 200, still more preferably 4 to 100, hydrogen atoms (SiH groups) bonded to a silicon atom in one molecule. May be linear, cyclic, or branched, and a known organohydrogenpolysiloxane can be used as a crosslinking agent for the addition reaction-curable silicone rubber composition. The organohydrogenpolysiloxane represented by the average composition formula (2) can be used.

R ² _c H _d SiO _(4-cd)/2 (2)
In the above average composition formula (2), R ^2's independently of each other represent an unsubstituted or substituted monovalent hydrocarbon group, and in particular, those having an aliphatic unsaturated bond removed are preferable. R ² usually has 1 to 12 carbon atoms, preferably 1 to 8 carbon atoms, and specifically, alkyl groups such as methyl group, ethyl group and propyl group, cycloalkyl groups such as cyclohexyl group and phenyl. Groups, aryl groups such as tolyl group, benzyl group, 2-phenylethyl group, aralkyl groups such as 2-phenylpropyl group, and groups in which some or all of the hydrogen atoms of these groups are substituted with halogen atoms, for example, , 3,3,3-trifluoropropyl group and the like.
In the above average composition formula (2), c and d are 0≦c<3, preferably 1≦c≦2.2, 0<d≦3, preferably 0.002≦d≦1, 0<c+d. It is a positive number that satisfies ≦3, preferably 1.002≦c+d≦3.

Organohydrogenpolysiloxane has two or more, preferably three or more, SiH groups in one molecule, which may be at the end of the molecular chain, in the middle of the molecular chain, or at both. Good.

The organohydrogenpolysiloxane preferably has a viscosity at 25° C. of 0.5 to 10,000 mPa·s, particularly 1 to 300 mPa·s. In the present invention, the viscosity is a value measured by a rotational viscometer (hereinafter the same).

Specific examples of such an organohydrogenpolysiloxane include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, and tris(hydrogendimethylsiloxy). ) Methylsilane, tris(hydrogendimethylsiloxy)phenylsilane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane/dimethylsiloxane cyclic copolymer, both ends trimethylsiloxy group blocked methylhydrogenpolysiloxane, both ends trimethylsiloxy group blocked Dimethyl siloxane/methyl hydrogen siloxane copolymer, both ends dimethyl hydrogen siloxy group blocked dimethyl polysiloxane, both ends dimethyl hydrogen siloxy group blocked dimethyl siloxane/methyl hydrogen siloxane copolymer, both ends trimethyl siloxy group blocked methyl hydro Gensiloxane/diphenylsiloxane copolymer, trimethylsiloxy group-blocked methylhydrogensiloxane/diphenylsiloxane/dimethylsiloxane copolymer at both ends, trimethylsiloxy group-blocked methylhydrogensiloxane/methylphenylsiloxane/dimethylsiloxane copolymer at both ends, Dimethylhydrogensiloxy group-capped methylhydrogensiloxane/dimethylsiloxane/diphenylsiloxane copolymer at both ends, Dimethylhydrogensiloxy group-capped methylhydrogensiloxane/dimethylsiloxane/methylphenylsiloxane copolymer at both ends, (CH ₃ ) ₂ Copolymer composed of HSiO _1/2 unit, (CH ₃ ) ₃ SiO _1/2 unit and SiO _4/2 unit, Copolymer composed of (CH ₃ ) ₂ HSiO _1/2 unit and SiO _4/2 unit In the above-exemplified compounds, a part of the methyl group, a copolymer composed of (CH ₃ ) ₂ HSiO _1/2 units, SiO _4/2 units and (C ₆ H ₅ ) ₃ SiO _1/2 units, etc. Or the thing which substituted all the other alkyl groups, a phenyl group, etc. is mentioned. Specific examples of such an organohydrogenpolysiloxane include compounds represented by the following structural formulas.

（式中、ｆは２〜１０の整数、ｇ及びｈは０〜１０の整数である。）
これらのオルガノハイドロジェンポリシロキサンは、１種単独で用いても、２種以上を組み合わせて用いてもよい。

(In the formula, f is an integer of 2 to 10, and g and h are integers of 0 to 10.)
These organohydrogenpolysiloxanes may be used alone or in combination of two or more.

The amount of the organohydrogenpolysiloxane blended is preferably 0.1 to 40 parts by mass, more preferably 0.3 to 20 parts by mass, relative to 100 parts by mass of the organopolysiloxane of component (A).

The organohydrogenpolysiloxane has a hydrogen atom (SiH group) bonded to a silicon atom in the organohydrogenpolysiloxane relative to an aliphatic unsaturated group (alkenyl group) bonded to the silicon atom in the component (A). The molar ratio (SiH group/aliphatic unsaturated group) is preferably 0.5 to 10 mol/mol, more preferably 0.7 to 5 mol/mol. If it is less than 0.5 mol/mol, crosslinking may be insufficient and sufficient mechanical strength may not be obtained, and if it exceeds 10 mol/mol, physical properties after curing may be deteriorated, and particularly heat resistance and The compression set may deteriorate.

The hydrosilylation catalyst is a catalyst that causes an addition reaction between the alkenyl group of the component (A) and the silicon atom-bonded hydrogen atom (SiH group) of the organohydrogenpolysiloxane.

Examples of the hydrosilylation catalyst include platinum group metal-based catalysts, and include platinum group metal simple substances and compounds thereof. For this, conventionally known catalysts for addition reaction curable silicone rubber compositions can be used. Examples thereof include fine particle platinum metal adsorbed on a carrier such as silica, alumina or silica gel, platinum chloride, chloroplatinic acid, alcohol solution of chloroplatinic acid hexahydrate, palladium catalyst, rhodium catalyst, and the like. Platinum or a platinum compound is preferred.

The addition amount of the hydrosilylation catalyst may be such that it can accelerate the addition reaction, and it is usually used in the range of 1 mass ppm to 1 mass% with respect to the organopolysiloxane of the component (A) in terms of the amount of platinum metal. However, the range of 10-500 mass ppm is preferable. If the addition amount is less than 1 mass ppm, the addition reaction may not be sufficiently promoted and the curing may be insufficient. On the other hand, if the addition amount exceeds 1 mass %, more than this may be added. It may be uneconomical because the influence on reactivity is reduced.
These hydrosilylation catalysts may be used alone or in combination of two or more.

(C-2) Organic peroxide curing agent Examples of the organic peroxide curing agent include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, 2, 4-dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, di-t-butylperoxide, t-butylperbenzoate, 1,6-hexanediol-bis- Examples thereof include t-butyl peroxycarbonate. These organic peroxide curing agents may be used alone or in combination of two or more.

The addition amount of the organic peroxide curing agent is preferably 0.1 to 10 parts by mass, and particularly preferably 0.2 to 5 parts by mass with respect to 100 parts by mass of the organopolysiloxane as the component (A). If the blending amount is too small, the curing of the silicone rubber composition may be insufficient. Conversely, if the blending amount is too large, the cured product of the silicone rubber will turn yellow due to the decomposition residue of the organic peroxide. There are cases.

In addition, the component (A) and the component (C-1) and the component (C-2) were combined and blended within the ranges of the above blending amounts, and the addition reaction curing and the organic peroxide curing were used together. A co-vulcanization type silicone rubber composition can also be used.

[(D) Ionic liquid]
The ionic liquid as the component (D) is an ionic liquid having at least one polymerizable reactive group in one molecule and containing a phosphonium type cation and a fluorine-containing anion.

Here, the phosphonium-type cation preferably contains an organopolysiloxane structure having a polymerizable reactive group.

Further, the fluorine-containing anion is preferably a trifluoromethanesulfonic acid anion, a bis(trifluoromethanesulfonyl)imide (TFSI) anion, a tetrafluoroborate anion or a hexafluorophosphate anion, and a bis(trifluoromethanesulfonyl)imide (TFSI). ) More preferably, it is an anion.

（式中、Ｙは重合性反応基であり、Ｚは単結合又はオルガノポリシロキサン構造を含む２〜２０価の基であり、Ｒ³は互いに独立して単結合、又は非置換若しくは置換の炭素数１〜２０の２価炭化水素基であり、Ｒ⁴、Ｒ⁵及びＲ⁶はそれぞれ互いに独立して非置換若しくは置換の炭素数１〜１０のアルキル基、又は炭素数６〜１０のアリール基である。また、ｒは１〜１０の整数、ｓは１〜１０の整数であり、かつｒ＋ｓがＺの価数に対応する２〜２０の整数である。） The ionic liquid (D) is more preferably an ionic liquid having a structure represented by the following formula (3) (hereinafter referred to as ionic liquid (3)).

(In the formula, Y is a polymerizable reactive group, Z is a single bond or a divalent to 20-valent group containing an organopolysiloxane structure, R ³ is independently a single bond, or an unsubstituted or substituted carbon atom. A divalent hydrocarbon group having 1 to 20 carbon atoms, and R ⁴ , R ⁵ and R ⁶ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. In addition, r is an integer of 1 to 10, s is an integer of 1 to 10, and r+s is an integer of 2 to 20 corresponding to the valence of Z.)

In the formula (3), Y is a polymerizable reactive group, and is preferably a vinyl group, a vinyloxy group, an acryloxy group, a (meth)acryloxy group, a (meth)acrylamide group, a styryl group or a styryloxy group. A group, an acryloxy group, a (meth)acryloxy group or a (meth)acrylamide group is more preferable, and a vinyl group, an acryloxy group or a (meth)acryloxy group is further preferable.

Z is a 2- to 20-valent, preferably 2- to 10-valent, and more preferably 2- to 6-valent group containing a single bond or an organopolysiloxane structure. Of these, a divalent linear diorganopolysiloxane is preferable as the divalent to divalent group containing an organopolysiloxane structure.

The divalent linear diorganopolysiloxane is specifically a repeating structure of diorganosiloxane units (R ¹ ₂ SiO _2/2 , R ¹ is the same as above) constituting the linear diorganopolysiloxane. A phenyl group, a 3,3,3-trifluoropropyl group, etc. as a part of the dimethylpolysiloxane structure composed of repeating dimethylsiloxane units or repeating dimethylsiloxane units forming the main chain. Those having a diorganosiloxane unit such as a diphenylsiloxane unit, a methylphenylsiloxane unit, or a methyl-3,3,3-trifluoropropylsiloxane unit, which has a substituent, are preferable. The repeating number of the diorganosiloxane unit is preferably 1 to 50, more preferably 2 to 30.

R ³ is independently a single bond or an unsubstituted or substituted divalent hydrocarbon group having 1 to 20 carbon atoms, and specific examples thereof include a methylene group, an ethylene group, a trimethylene group, a propylene group and an isopropylene group. Group, tetramethylene group, isobutylene group, pentamethylene group, hexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, tridecamethylene group, tetradecamethylene group, Alkylene groups such as pentadecamethylene group, hexadecamethylene group, heptadecamethylene group, octadecamethylene group, nonadecamethylene group, eicosadecylene group; cycloalkylene groups such as cyclopentylene group, cyclohexylene group; phenylene group, Examples include arylene groups such as α- and β-naphthylene groups. Incidentally, some or all of the hydrogen atoms of these groups may be substituted with an alkyl group, an aryl group, a halogen atom such as F, Cl, Br, I, etc., a cyano group, etc., and specific examples thereof include: 2-chloroethylene group, 2-bromoethylene group, 2-chloropropylene group, 2-bromopropylene group, 1-chloromethylethylene group, 1-bromomethylethylene group, 2-chlorooctamethylene group, 2-bromooctamethylene Group, 1-chloromethylheptamethylene group, 1-bromomethylheptamethylene group and the like.

Here, as Y—R ³ — in the above formula (3), a vinyl group, an acryloxymethyl group, a 5-hexenyl group, a 9-decenyl group, a vinyloxymethyl group, a 3-vinyloxypropyl group, (meth) Acryloxymethyl group, 3-(meth)acryloxypropyl group, 11-(meth)acryloxyundecyl group, vinylphenyl group (styryl group), isopropenylphenyl group (α-methylstyryl group), vinylphenylmethyl group (Vinylbenzyl group) can be shown as a specific example. It is preferable to use a vinyl group, an acryloxymethyl group or a (meth)acryloxymethyl group from the viewpoint of reactivity and availability.

R ⁴ , R ⁵ and R ⁶ are each independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms.
In the above R ⁴ , R ⁵ and R ⁶ , the alkyl group having 1 to 10 carbon atoms may be linear, cyclic or branched, and specific examples thereof include a methyl group, an ethyl group and n. -Propyl group, isopropyl group, n-butyl group, s-butyl group, tert-butyl group, n-pentyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, Examples thereof include linear or branched alkyl groups such as n-decyl group, cyclopropyl groups, cyclobutyl groups, cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, cyclooctyl groups, isobornyl groups and other cycloalkyl groups.
Further, specific examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a tolyl group, a xylyl group, an α-naphthyl group, a β-naphthyl group and the like.
Incidentally, some or all of the hydrogen atoms of these groups may be substituted with an alkyl group, an aryl group, a halogen atom such as F, Cl, Br or the like, a cyano group or the like, and specific examples thereof include 3- A chloropropyl group, a 3,3,3-trifluoropropyl group, a 2-cyanoethyl group and the like can be mentioned.
Among these, as R ⁴ , R ⁵ and R ⁶ , a methyl group, an ethyl group and a phenyl group are preferable, and a methyl group and an ethyl group are more preferable in terms of reactivity, easy availability, productivity and cost.

In the above formula (3), r is an integer of 1 to 10, s is an integer of 1 to 10, and r+s is an integer of 2 to 20 corresponding to the valence of Z, and preferably r is 1 to 5. Is an integer of 1 to 5, and r+s is an integer of 2 to 10 corresponding to the valence of Z, more preferably r is an integer of 1 to 3, s is an integer of 1 to 3, and r+s. Is an integer of 2 to 60 corresponding to the valence of Z, and more preferably r=s=1.

Specific examples of the ionic liquid (D) include the following.

These ionic liquids may be used alone or in combination of two or more.

The compounding amount of the ionic liquid of the component (D) is 100 parts by mass of the base compound (that is, the organopolysiloxane of the component (A), the reinforcing silica of the component (B), and a silica surface treating agent which is an optional component). It is 0.001 to 5 parts by mass, preferably 0.005 to 0.1 parts by mass, based on 100 parts by mass of the total amount of the dispersant.
When the compounding amount of the component (D) is less than the above range, the antistatic effect is not exhibited, and when it exceeds the above range, the physical properties of the cured product are deteriorated, which is not economically preferable.

The ionic liquid (3) is an organopolysiloxane compound having a polymerizable reactive group Y and a silanol group hydroxyl group (hereinafter referred to as a silanol group hydroxyl group-containing organopolysiloxane compound (4)) represented by the following structural formula (4). And a compound having a functional group (leaving group X) capable of reacting with the silanol hydroxyl group and an ionic group represented by the formula (5) (hereinafter referred to as ionic compound (5)) be able to. More specifically, a dealcohol reaction, dehydrohalogenation reaction and dehydration between the silanol hydroxyl group of the silanol hydroxyl group-containing organopolysiloxane compound (4) and the leaving group X of the ionic compound (5). A reaction for forming a siloxane bond is performed according to any reaction mode of the reaction.

（式中、Ｒ³、Ｒ⁴、Ｒ⁵、Ｒ⁶、Ｙ、ｒ、ｓ、Ｚは、上記と同じである。Ａは含フッ素アニオンである。ＯＨは、シラノール性水酸基を表し、Ｘは、炭素原子数１〜１０のアルコキシ基、ハロゲン原子及びヒドロキシル基（−ＯＨ基）から選ばれる脱離基を表す。）

(In the formula, R ³ , R ⁴ , R ⁵ , R ⁶ , Y, r, s, and Z are the same as above. A is a fluorine-containing anion. OH represents a silanol group and X represents X. Represents a leaving group selected from an alkoxy group having 1 to 10 carbon atoms, a halogen atom and a hydroxyl group (—OH group).

The fluorinated anion A is preferably a trifluoromethanesulfonic acid anion, a bis(trifluoromethanesulfonyl)imide (TFSI) anion, a tetrafluoroborate anion or a hexafluorophosphate anion, and a bis(trifluoromethanesulfonyl)imide (TFSI) anion. Is more preferable.

As the alkoxy group having 1 to 10 carbon atoms in the leaving group X, the alkyl group therein may be linear, cyclic or branched, and specific examples thereof include methoxy. , Ethoxy, n-propoxy, isopropoxy, n-butoxy, t-butoxy, n-pentoxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy and n-decyloxy groups. From the viewpoint of reactivity, an alkoxy group having 1 to 3 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is even more preferable.
Examples of the halogen atom include a chlorine atom, a bromine atom and an iodine atom, and a chlorine atom is preferable from the viewpoint of reactivity.

Specific examples of the ionic compound (5) include tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(fluorosulfonyl)imide, tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trihexyl. {(Chlorodimethylsilyl)methyl}phosphonium=bis(fluorosulfonyl)imide, trihexyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl{(chlorodimethylsilyl)methyl}phosphonium=bis(fluoro) Sulfonyl)imide, trioctyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, tributyl{3-(chlorodimethylsilyl)propyl}phosphonium=bis(fluorosulfonyl)imide, tributyl{3-(chlorodimethyl) (Silyl)propyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl{3-(chlorodimethylsilyl)propyl}phosphonium=bis(fluorosulfonyl)imide, trioctyl{3-(chlorodimethylsilyl)propyl}phosphonium=bis(trifluoro) Rhomethanesulfonyl)imide, tributyl{8-(chlorodimethylsilyl)octyl}phosphonium=bis(fluorosulfonyl)imide, tributyl{8-(chlorodimethylsilyl)octyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl{8- (Chlorodimethylsilyl)octyl}phosphonium=bis(fluorosulfonyl)imide, trioctyl{8-(chlorodimethylsilyl)octyl}phosphonium=bis(trifluoromethanesulfonyl)imide, tributyl{(methoxydimethylsilyl)methyl}phosphonium=bis( Fluorosulfonyl)imide, tributyl{(methoxydimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl{(methoxydimethylsilyl)methyl}phosphonium=bis(fluorosulfonyl)imide, trioctyl{(methoxydimethylsilyl)methyl } Phosphonium=bis(trifluoromethanesulfonyl)imide, tributyl{(ethoxydimethylsilyl)methyl} Phosphonium=bis(fluorosulfonyl)imide, tributyl{(ethoxydimethylsilyl)methyl} Phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl{(ethoxydimethylsilyl)methyl}phosphonium=bis(fluorosulfonyl)imide, trioctyl{(ethoxydimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, tributyl{( Dimethylsilanol)methyl}phosphonium=bis(fluorosulfonyl)imide, tributyl{(dimethylsilanol)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl{(dimethylsilanol)methyl}phosphonium=bis(fluorosulfonyl)imide, trioctyl Examples thereof include, but are not limited to, {(dimethylsilanol)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide.

Among these, tributyl{(chlorodimethylsilyl)methyl}phosphonium from the viewpoint of reactivity with the silanol-containing hydroxyl group-containing organopolysiloxane compound (4), antistatic property of the obtained organopolysiloxane compound and durability thereof. =bis(trifluoromethanesulfonyl)imide, trioctyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, tributyl{3-(chlorodimethylsilyl)propyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl {3-(chlorodimethylsilyl)propyl}phosphonium=bis(trifluoromethanesulfonyl)imide, tributyl{8-(chlorodimethylsilyl)octyl}phosphonium=bis(trifluoromethanesulfonyl)imide, trioctyl{8-(chlorodimethylsilyl) Octyl}phosphonium=bis(trifluoromethanesulfonyl)imide is preferred.

The siloxane bond forming reaction between the silanol hydroxyl group of the silanol hydroxyl group-containing organopolysiloxane compound (4) and the leaving group X of the ionic compound (5) can be carried out by a conventionally known general method. .. More specifically, in the presence of a basic compound, the silanol-containing hydroxyl group-containing organopolysiloxane compound (4) and the ionic compound (5) are subjected to any one of dealcoholization reaction, dehydrohalogenation reaction and dehydration reaction. A reaction for forming a siloxane bond is performed depending on the reaction mode.

As the basic compound, various basic compounds which are usually used in the siloxane bond forming reaction can be used.
Specifically, alkali metal hydrides such as sodium hydride, lithium hydride, potassium hydride, and cesium hydride; alkaline earth metal hydrides such as calcium hydride; lithium hydroxide, sodium hydroxide, potassium hydroxide , Alkali metal hydroxides such as cesium hydroxide and aqueous solutions thereof; alkaline earth metal hydroxides such as barium hydroxide and calcium hydroxide and aqueous solutions thereof; alkali metal and alkali such as potassium t-butoxide and sodium t-butoxide Earth alkoxides; alkali metal and alkaline earth metal carbonates such as potassium carbonate, sodium carbonate and calcium carbonate; alkali metal and alkaline earth hydrogen carbonates such as sodium hydrogen carbonate and potassium hydrogen carbonate; triethylamine, tributylamine, N, Examples include tertiary amines such as N-diisopropylethylamine, tetramethylethylenediamine, pyridine, N,N-dimethyl-4-aminopyridine and the like. Among these, tertiary amines such as triethylamine, tributylamine, N,N-diisopropylethylamine, tetramethylethylenediamine, pyridine, and N,N-dimethyl-4-aminopyridine are preferable from the viewpoint of reaction efficiency, and triethylamine and tributylamine are preferable. Is more preferable.

In the siloxane bond-forming reaction, a solvent that dissolves the used raw material and does not react with the used raw material can be used. Specific examples thereof include hydrocarbon solvents such as pentane, hexane, heptane, octane, decane, and cyclohexane; aromatic solvents such as benzene, toluene, xylene; formamide, N,N-dimethylformamide, pyrrolidone, N-methyl. Amide solvents such as pyrrolidone; diethyl ether, dibutyl ether, cyclopentyl methyl ether, tetrahydrofuran, ether solvents such as 1,4-dioxane; nitrile solvents such as acetonitrile, and the like. You may use it in combination of 2 or more types. Among these, from the viewpoint of reaction efficiency, toluene, xylene, dimethylformamide, cyclopentyl methyl ether, tetrahydrofuran and acetonitrile are preferable, and acetonitrile is more preferable.

A phenol derivative such as 3,5-di-t-butyl-4-hydroxytoluene (BHT) may be added as a reaction accelerator.

The addition amount of the ionic compound (5) in the siloxane bond-forming reaction is preferably such that the silanol hydroxyl group of the silanol hydroxyl group-containing organopolysiloxane compound (4) is completely consumed.

The reaction temperature at the time of forming a siloxane bond is not particularly limited, but in consideration of making the reaction rate appropriate, 0 to 100°C is preferable, 25 to 80°C is preferable, and 40 to 70°C is even more preferable. preferable.
The reaction time is not particularly limited, but is usually 10 minutes to 24 hours.

[Other optional ingredients]
In addition to the above-mentioned components, the silicone rubber composition of the present invention may optionally contain quartz powder, crystalline silica, non-reinforcing silica such as diatomaceous earth, acetylene black, furnace black, carbon black such as channel black (however, , Limited to the compounding amount that can maintain the insulating property), colorants, red iron oxide, heat resistance improvers such as cerium oxide, flame retardant improvers such as platinum compounds other than the above platinum group metal catalysts, titanium oxide, triazole compounds, etc. An acid agent, a thermal conductivity improver such as alumina or boron nitride, a release agent, a dispersant such as water, a reaction control agent such as ethynylcyclohexanol, and the like may be added. These optional components may be used alone or in combination of two or more.

The antistatic silicone rubber composition of the present invention can be obtained by uniformly mixing the above components using a mixing device such as a two-roll mill, a Banbury mixer, a Dow mixer (kneader). ) And component (B) (silica surface treating agent or dispersant, which is an optional component as necessary, and further water if necessary) to prepare a base compound, and then components (C) and (D) (A part of the component (A)) may be blended, or the components (A), (B) and (D) (further optionally, a silica surface treating agent or dispersion which is an optional component). The agent (C) may be mixed and prepared, and then the component (C) may be blended. In addition, in the mixing before adding the component (C) such as when preparing the base compound, heat treatment is performed at 20 to 250° C., particularly 50 to 200° C. for 0.1 to 10 hours, particularly 0.1 to 5 hours. It is preferable to prepare.

By molding the antistatic silicone rubber composition of the present invention at the same time as heat curing, a molded product made of a rubber-like elastic body (silicone rubber cured product) can be obtained.
The method for curing the above silicone rubber composition is not particularly limited, but any method may be used as long as it is sufficient to decompose the curing agent and vulcanize the silicone rubber composition. The temperature condition for curing depends on the curing method, but is usually 80 to 400° C., particularly 100 to 200° C., 3 seconds to 160 minutes, and particularly 3 seconds to 20 minutes. The molding method is not particularly limited, and for example, molding methods such as continuous vulcanization by extrusion molding, press molding (pressure molding), injection molding and the like can be adopted. Further, if necessary, secondary vulcanization (post cure) may be performed at 150 to 250° C. for about 1 to 10 hours.

As described above, the antistatic silicone rubber composition of the present invention is a silicone rubber composition that provides a cured silicone rubber product that maintains insulation and is excellent in antistatic properties and has little bleeding even when exposed to high temperatures. It becomes a thing.

Specifically, the volume resistivity of a cured product obtained by heating and curing the silicone rubber composition of the present invention is 1 GΩ·m (1×10 ⁹ Ω·m) or more, particularly 2 GΩ, measured according to JIS K6249. It is preferably at least m (2×10 ⁹ Ω·m). Within the above range, the insulation level can be sufficiently used for electric wire coating, keypad applications and the like.

As the antistatic performance, a static Honest meter (manufactured by Shishido Electrostatic Co., Ltd.) was used to charge the surface of the cured silicone rubber product with 6 kV of static electricity by corona discharge, and then the charged voltage was 3 kV (half). The time (half-life) is 2 minutes or less, preferably 1 minute or less, and more preferably 5 seconds or less.

The silicone rubber cured product obtained by curing the above-mentioned antistatic silicone rubber composition according to the present invention is charged due to static electricity or adsorption of dust in the air in the semiconductor-related fields, electronic equipment fields, precision equipment fields, etc. It can be used in a wide range of applications where prevention performance is required. For example, small electronic components such as capacitors and resistors are aligned and held when the contacts are formed by coating silver or palladium on both ends. It can be suitably used for an antistatic carrier plate used for For example, a silicone rubber cured product obtained by curing the antistatic silicone rubber composition of the present invention may be applied to the rubber-like elastic body forming the carrier plate described in JP-A-2006-344826.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
In addition, in the following examples, the viscosity indicates a value at 25° C. measured by a rotational viscometer. The content (mass %) of the hydroxyl group (silanolic hydroxyl group) in the silanol group contained in each product was quantified from the amount of methane gas generated when the Grignard reagent (methylmagnesium iodide) was allowed to act on each product. Room temperature means 25±5° C.
The ionic liquid average composition in the following examples was calculated from the integrated value of the detection spectrum in ¹ H-NMR and ²⁹ Si-NMR using a 300 MHz-NMR measuring device manufactured by JEOL Ltd.
Further, TFSI ⁻ in the average composition of the ionic liquid below represents a bis(trifluoromethanesulfonyl)imide anion.

Synthesis Example 1 Synthesis of Ionic Liquid 1 A 200 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer was added to the silanol-containing hydroxyl group-containing organopolysiloxane compound represented by the following formula (6). 8 g, toluene 45 g, 3,5-di-t-butyl-4-hydroxytoluene 0.03 g and triethylamine 3.2 g were charged and heated to 40°C. 35.2 g of a 50 mass% toluene solution of tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide as an ionic compound was added dropwise thereto, and the mixture was heated and stirred at 50° C. for 2 hours. By measuring the silanol-containing hydroxyl group content, it was confirmed that the silanol-containing hydroxyl group derived from the starting silanol-containing hydroxyl group-containing organopolysiloxane compound was completely consumed and reached 0% by mass, and the reaction was terminated.
The mixture after completion of the reaction was washed twice with 30 g of 10% by mass Glauber's salt water and subjected to liquid separation, and then distilled under reduced pressure (80° C., 5 mmHg) for 1 hour, followed by filtration. 17 g of the ionic liquid 1 represented by the formula (7) was obtained.

[Synthesis example 2] Synthesis of ionic liquid 2 In a 200 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer, 21 g of a silanol-containing hydroxyl group-containing organopolysiloxane compound represented by the following formula (8): 10 g of toluene, 40 g of acetonitrile, 0.03 g of 3,5-di-t-butyl-4-hydroxytoluene and 5.8 g of triethylamine were charged and heated to 40°C. 64.8 g of a 50 mass% toluene solution of tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide as an ionic compound was added dropwise thereto, and the mixture was heated and stirred at 50° C. for 2 hours. By measuring the silanol-containing hydroxyl group content, it was confirmed that the silanol-containing hydroxyl group derived from the starting silanol-containing hydroxyl group-containing organopolysiloxane compound was completely consumed and reached 0% by mass, and the reaction was terminated.
After completion of the reaction, the mixture was washed twice with 100 g of 10% by mass Glauber's salt water and subjected to liquid separation operation, and then distilled under reduced pressure (80° C., 5 mmHg) for 1 hour, followed by filtration. 49 g of the ionic liquid 2 represented by the formula (9) was obtained.

[Synthesis Example 3] Synthesis of Ionic Liquid 3 A 200 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer was added to a silanol-containing hydroxyl group-containing organopolysiloxane compound 33. represented by the following formula (10). 2 g, 10 g of toluene, 40 g of acetonitrile, 0.04 g of 3,5-di-t-butyl-4-hydroxytoluene and 5.8 g of triethylamine were charged and heated to 40°C. 64.8 g of a 50 mass% toluene solution of tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide as an ionic compound was added dropwise thereto, and the mixture was heated and stirred at 50° C. for 2 hours. By measuring the silanol-containing hydroxyl group content, it was confirmed that the silanol-containing hydroxyl group derived from the starting silanol-containing hydroxyl group-containing organopolysiloxane compound was completely consumed and reached 0% by mass, and the reaction was terminated.
After completion of the reaction, the mixture was washed twice with 100 g of 10% by mass Glauber's salt water and subjected to liquid separation operation, and then distilled under reduced pressure (80° C., 5 mmHg) for 1 hour, followed by filtration. 60 g of the ionic liquid 3 represented by the formula (11) was obtained.

[Synthesis Example 4] Synthesis of ionic liquid 4 In a 200 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel, and a thermometer, a silanol-containing hydroxyl group-containing organopolysiloxane compound 45. 4 g, toluene 6.5 g, acetonitrile 50 g, 0.05 g of 3,5-di-t-butyl-4-hydroxytoluene and 3.8 g of triethylamine were charged and heated to 40°C. 42.1 g of a 50 wt% toluene solution of tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide was added dropwise thereto as an ionic compound, and the mixture was heated with stirring at 50° C. for 2 hours. By measuring the silanol-containing hydroxyl group content, it was confirmed that the silanol-containing hydroxyl group derived from the starting silanol-containing hydroxyl group-containing organopolysiloxane compound was completely consumed and reached 0% by mass, and the reaction was terminated.
After completion of the reaction, the mixture was washed twice with 100 g of 10% by mass Glauber's salt water and subjected to liquid separation operation, and then distilled under reduced pressure (80° C., 5 mmHg) for 1 hour, followed by filtration. 58 g of the ionic liquid 4 represented by the formula (13) was obtained.

[Synthesis Example 5] Synthesis of Ionic Liquid 5 In Synthesis Example 3, a 50 mass% toluene solution of tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide, which is an ionic compound, was added to trioctyl{(chloro). Dimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide 50 wt% in toluene solution was changed to 83.3 g, except that it was synthesized by the same procedure as Synthesis Example 3, the ion represented by the following formula (14) 55 g of liquid 5 was obtained.

[Synthesis Example 6] Synthesis of ionic liquid 6 In a 200 mL separable flask equipped with a stirrer, a reflux condenser, a dropping funnel and a thermometer, 18 g of a silanol-containing hydroxyl group-containing organopolysiloxane compound represented by the following formula (15), 10 g of toluene, 40 g of acetonitrile, 0.05 g of 3,5-di-t-butyl-4-hydroxytoluene and 5.8 g of triethylamine were charged and heated to 40°C. 65.0 g of a 50 mass% toluene solution of tributyl{(chlorodimethylsilyl)methyl}phosphonium=bis(trifluoromethanesulfonyl)imide as an ionic compound was added dropwise thereto, and the mixture was heated with stirring at 50° C. for 2 hours. By measuring the silanol-containing hydroxyl group content, it was confirmed that the silanol-containing hydroxyl group derived from the starting silanol-containing hydroxyl group-containing organopolysiloxane compound was completely consumed and reached 0% by mass, and the reaction was terminated.
After completion of the reaction, the mixture was washed twice with 100 g of 10% by mass Glauber's salt water and subjected to liquid separation operation, and then distilled under reduced pressure (80° C., 5 mmHg) for 1 hour, followed by filtration. 50 g of the ionic liquid 6 represented by the formula (16) was obtained.

[Synthesis Example 7] Synthesis of Ionic Liquid 7 In Synthesis Example 3, a 50 mass% toluene solution of tributyl {(chlorodimethylsilyl)methyl}phosphonium bis(trifluoromethanesulfonyl)imide, which is an ionic compound, was added to tributyl {(chloro). Dimethylsilyl)methyl}phosphonium = 45 mass% of an ionic liquid 7 represented by the following formula (17) was obtained by the same procedure as in Synthesis Example 3 except that the 72% by mass acetonitrile solution was changed to 26.4 g. ..

[Synthesis Example 8] Synthesis of Ionic Liquid 8 96.5 g of 1,1,1-tributyl-1-(trimethoxysilylpropyl)phosphonium chloride was dissolved in 440 g of acetone, and lithium bis(trifluoromethanesulfonyl)imidate 70. 5 g were mixed and stirred at room temperature for 24 hours. The obtained reaction solution was concentrated with an evaporator, 177.2 g of ethyl acetate was added to the concentrated residue, and the precipitated crystals were removed by filtration. The crystals were concentrated again with an evaporator and represented by the following formula (18). 150 g of ionic liquid 8 was obtained.

[Example 1]
(A-1) Containing 99.850 mol% of a dimethylsiloxane unit as a diorganosiloxane unit constituting the main chain, 0.125 mol% of a methylvinylsiloxane unit, and 0.025 mol% of a dimethylvinylsiloxy group as a molecular chain end group. 100 parts by weight of linear organopolysiloxane (raw rubber) having an average degree of polymerization of about 6,000, (B-1) BET specific surface area of 200 m ² /g fumed silica (trade name "Aerosil 200", Nippon Aerosil (Manufactured by K.K.) 40 parts by mass, 6 parts by mass of dimethylpolysiloxane having silanol groups at both ends as a dispersant and having an average degree of polymerization of 15 and a viscosity at 25° C. of 30 mPa·s were kneaded with a kneader to obtain 170. Base compound 1 was prepared by heating at 2° C. for 2 hours.
With respect to 100 parts by mass of the "base compound 1", 0.01 parts by mass of (D-1) the ionic liquid 1 represented by the formula (7) obtained in the above Synthesis Example 1, and (C-1) as the cross-linking agent 2, 0.4 parts by mass of 5-dimethyl-2,5-bis(t-butylperoxy)hexane was added and uniformly mixed to obtain a silicone rubber composition 1.
The silicone rubber composition 1 was press-cured (primary vulcanization) at 170° C./10 minutes, and then post-cured (secondary vulcanization) at 200° C./4 hours in an oven to form a sheet-shaped silicone having a thickness of 2 mm. A rubber cured product was obtained.

[Example 2]
In Example 1, (D-1) ionic liquid 1 was changed to ionic liquid 2 represented by formula (9) obtained in (D-2) Synthesis Example 2, and otherwise the same as in Example 1 to prepare a silicone rubber composition. Item 2 was obtained.
The obtained silicone rubber composition 2 was cured under the same conditions as in Example 1 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Example 3]
In Example 1, the ionic liquid 1 (D-1) was changed to the ionic liquid 3 represented by Formula (11) obtained in Synthesis Example 3 (D-3), and otherwise the same as in Example 1, except that the silicone rubber composition was used. Item 3 was obtained.
The obtained silicone rubber composition 3 was cured under the same conditions as in Example 1 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Comparative Example 1]
A silicone rubber composition 4 was obtained in the same manner as in Example 1 except that (D-1) Ionic liquid 1 was not added in Example 1.
The obtained silicone rubber composition 4 was cured under the same conditions as in Example 1 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

Using the obtained silicone rubber cured product, antistatic property, volume resistivity, bleeding property, and yellowing were evaluated as follows.

(Measurement of antistatic property (half-life measuring method))
Using static Honest meter (manufactured by Shishido Electrostatics Co., Ltd.), the surface voltage of the cured silicone rubber after post-curing (initial) was charged with static electricity of 6 kV by corona discharge, and then the charged voltage became half (3 kV). Was measured.
(Measurement of volume resistivity)
Based on JIS K6249, the volume resistivity of the cured silicone rubber product after post cure was measured.

The post-cure silicone rubber cured product was allowed to stand in a dryer at 200° C. for 3 days as a heat resistance test, and then the silicone rubber cured product after the heat resistance test was subjected to the above-mentioned measurement of antistatic property. A strange evaluation was performed.
(Bleedability evaluation)
The presence or absence of bleeding of the ionic liquid on the surface of the cured silicone rubber product after the heat resistance test was visually observed.
(Evaluation of yellowing)
The presence or absence of yellowing of the cured silicone rubber product after the heat resistance test was visually observed.
The above results are shown in Table 1.

[Example 4]
(A-2) 60 parts by mass of dimethylpolysiloxane having both ends of the molecular chain blocked with dimethylvinylsiloxy groups and an average degree of polymerization of 750, (B-2) fume having a specific surface area of 300 m ² /g by the BET method. After mixing 40 parts by mass of dosilica (trade name "Aerosil 300", manufactured by Nippon Aerosil Co., Ltd.), 8 parts by mass of hexamethyldisilazane, and 2 parts by mass of water at room temperature for 30 minutes, the temperature was raised to 150° C., and 3 After continuing stirring for a time, the mixture was cooled to obtain a silicone rubber base composition.
To 100 parts by mass of this silicone rubber base composition, (A-2) 6 parts by mass of dimethylpolysiloxane having both ends of the molecular chain blocked with dimethylvinylsiloxy groups and having an average degree of polymerization of 750, (A-3) molecular chain 5 parts by mass of dimethylpolysiloxane having both ends blocked with trimethylsiloxy groups and containing vinylmethylsiloxane units in the main chain of diorganosiloxane units in an amount of 10 mol% and having an average degree of polymerization of 150, (D-3) 0.01 parts by mass of the ionic liquid 3 represented by the formula (11) obtained in 3 and 0.1 parts by mass of the (C-2) platinum catalyst (Pt concentration 1% by mass) and a SiH group in the side chain as a cross-linking agent. Methyl hydrogen polysiloxane (polymerization degree 38, SiH group 0.0074 mol% both ends trimethylsiloxy group blocked dimethylsiloxane/methyl hydrogen siloxane copolymer) 3 parts by mass (SiH group/vinyl group total amount=1. 75 mol/mol) and 0.05 part by mass of ethynylcyclohexanol as a reaction control agent were added, and stirring was continued for 15 minutes to obtain a silicone rubber composition 5. In this case, a combination of 100 parts by mass of the silicone rubber base composition and 6 parts by mass of the component (A-2) and 5 parts by mass of the component (A-3) added thereto is a base compound, The compounding amount of the component D-3) is 0.009 parts by mass with respect to 100 parts by mass of this base compound.
The silicone rubber composition 5 is press-cured (primary vulcanization) at 120° C./10 minutes, and then post-cured (secondary vulcanization) at 150° C./1 hour in an oven to form a sheet-shaped silicone having a thickness of 2 mm. A rubber cured product was obtained.

[Example 5]
In Example 4, the ionic liquid 3 (D-3) was changed to the ionic liquid 4 represented by the formula (13) obtained in (D-4) Synthesis Example 4, and otherwise the same as in Example 4 except that the silicone rubber composition was changed. Item 6 was obtained.
The obtained silicone rubber composition 6 was cured under the same conditions as in Example 4 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Example 6]
In Example 4, (D-3) ionic liquid 3 was changed to ionic liquid 5 represented by formula (14) obtained in (D-5) Synthesis Example 5, and otherwise the same as in Example 4, and the silicone rubber composition was used. Item 7 was obtained.
The obtained silicone rubber composition 7 was cured under the same conditions as in Example 4 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Example 7]
In Example 4, the ionic liquid 3 (D-3) was changed to the ionic liquid 6 represented by the formula (16) obtained in Synthesis Example 6 (D-6), and otherwise the same as in Example 4 except that the silicone rubber composition was changed. Item 8 was obtained.
The obtained silicone rubber composition 8 was cured under the same conditions as in Example 4 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Comparative example 2]
Silicone rubber composition 9 was obtained in the same manner as in Example 4, except that (D-3) Ionic liquid 3 was not added in Example 4.
The obtained silicone rubber composition 9 was cured under the same conditions as in Example 4 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Comparative Example 3]
In Example 4, the ionic liquid 3 (D-3) was changed to the ionic liquid 7 represented by the formula (17) obtained in (D-7) Synthesis Example 7, and otherwise the same as in Example 4 except that the silicone rubber composition was changed. Item 10 was obtained.
The obtained silicone rubber composition 10 was cured under the same conditions as in Example 4 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Comparative Example 4]
In Example 4, the ionic liquid 3 (D-3) was changed to the ionic liquid 8 shown in Formula (18) obtained in Synthesis Example 8 (D-8), and otherwise the same as in Example 4 except that the silicone rubber composition was changed. Item 11 was obtained.
The obtained silicone rubber composition 11 was cured under the same conditions as in Example 4 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

[Comparative Example 5]
In Example 4, (D-3) ionic liquid 3 was replaced with (D-9) the following formula (19).
_{N (CH 3) (C 8} H 17) 3 + TFSI - (19)
A silicone rubber composition 12 was obtained in the same manner as in Example 4 except that the ionic liquid 9 of methyltrioctylammonium=bis(trifluoromethanesulfonyl)imide shown in was changed to.
The obtained silicone rubber composition 12 was cured under the same conditions as in Example 4 to obtain a sheet-shaped cured silicone rubber product having a thickness of 2 mm.

Using the obtained silicone rubber cured product, the antistatic property, volume resistivity, bleeding property, and yellowing were evaluated.
The above results are shown in Table 2.

It should be noted that although the present invention has been described above with the above embodiment, the present invention is not limited to this embodiment and can be conceived by those skilled in the art such as other embodiments, additions, changes and deletions. It can be changed within the range and is included in the range of the present invention as long as the effects of the present invention are exhibited in any of the modes.

Claims (10)

A base composition containing a base compound containing an organopolysiloxane having two or more alkenyl groups bonded to a silicon atom in one molecule and a curing agent, which gives an insulating silicone rubber cured product by heat curing, at least in one molecule. Antistatic silicone rubber composition comprising one polymerizable reactive group and 0.001 to 5 parts by mass of an ionic liquid containing a phosphonium type cation and a fluorine-containing anion with respect to 100 parts by mass of the base compound. Stuff. The above-mentioned base compound has (A) a degree of polymerization of 100 or more, an organopolysiloxane having two or more alkenyl groups bonded to a silicon atom in one molecule: 100 parts by mass, and (B) a specific surface area by the BET method. The antistatic silicone rubber composition according to claim 1, which contains 50 to 100 parts by mass of reinforcing silica having a content of 50 m ² /g or more. The antistatic silicone rubber composition according to claim 1 or 2, wherein the phosphonium-type cation contains an organopolysiloxane structure having a polymerizable reactive group. The antistatic silicone rubber composition according to claim 1, wherein the fluorine-containing anion is a trifluoromethanesulfonate anion, a bis(trifluoromethanesulfonyl)imide anion, a tetrafluoroborate anion or a hexafluorophosphate anion. .. The antistatic silicone rubber composition according to any one of claims 1 to 4, wherein the ionic liquid is an ionic liquid represented by the following formula (3).

(In the formula, Y is a polymerizable reactive group, Z is a single bond or a divalent to 20-valent group containing an organopolysiloxane structure, R ³ is independently a single bond, or an unsubstituted or substituted carbon atom. A divalent hydrocarbon group having 1 to 20 carbon atoms, and R ⁴ , R ⁵ and R ⁶ each independently represent an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms. In addition, r is an integer of 1 to 10, s is an integer of 1 to 10, and r+s is an integer of 2 to 20 corresponding to the valence of Z.) The charging according to any one of claims 1 to 5, wherein the polymerizable reactive group is a vinyl group, a vinyloxy group, an acryloxy group, a (meth)acryloxy group, a (meth)acrylamide group, a styryl group or a styryloxy group. Preventive silicone rubber composition. The antistatic silicone rubber composition according to any one of claims 1 to 6, wherein the curing agent contains a combination of an organohydrogenpolysiloxane and a hydrosilylation catalyst. The antistatic silicone rubber composition according to claim 1, wherein the curing agent contains an organic peroxide. The antistatic agent according to any one of claims 1 to 8, which provides a silicone rubber cured product having an antistatic ability with a half-life of 2 kV or less after charging a static electricity of 6 kV to 3 kV. Silicone rubber composition. An antistatic carrier plate using a silicone rubber cured product obtained by curing the antistatic silicone rubber composition according to any one of claims 1 to 9.