JP6468115B2 - Addition-curable silicone rubber composition and cured product - Google Patents

Description

  The present invention relates to an addition-curable silicone rubber composition that gives a silicone rubber having high rubber strength and surface adhesion after curing, and a cured product thereof.

  The pressure-sensitive adhesive is also called a pressure-sensitive adhesive, and has a property of easily adhering to the surface of an object with a pressure small enough to be pressed with a fingertip. Such adhesives are used in adhesive products such as cellophane tape, vinyl tape for electrical insulation, masking tape, and adhesive sheet. As pressure-sensitive adhesives used in these pressure-sensitive adhesive tapes and sheets, those mainly composed of natural rubber, synthetic rubber, etc. are used, but these pressure-sensitive adhesive compositions are easily deteriorated by heat, light, etc. In addition, there is a problem that the adhesiveness is lowered at a low temperature. In contrast, silicone adhesives have excellent heat resistance, cold resistance, and electrical characteristics unique to silicones, and can have adhesiveness without impairing these characteristics, so that a high degree of reliability is required. Widely used in various adhesive products.

These silicone pressure-sensitive adhesives include silicone pressure-sensitive adhesives comprising polysiloxanes having (CH ₃ ) ₃ SiO _1/2 units and SiO ₂ units and dimethyl silicone raw rubber condensates, alkenyl group-containing organopolysiloxanes and organohydrogenpoly Addition-type silicone pressure-sensitive adhesives by hydrosilylation reaction of siloxane (Patent Documents 1 and 2: JP-B-54-37907, JP-A-63-22886) are known. However, these pressure-sensitive adhesives mainly form a thin film by coating and utilize the adhesiveness of the surface, and the rubber hardness and strength are not mentioned at all. Actually, even if these compositions are used as rubber sheets, the adhesive strength is sufficient, but they are not suitable for use in the manufacturing process of fixed sheets for jigs and electronic parts that are used repeatedly because of lack of rubber strength.

  Patent Document 3 (Japanese Patent Laid-Open No. 2004-189945) and Patent Document 4 (Japanese Patent Laid-Open No. 2006-225420) show high-strength silicone rubber adhesive materials. However, the silicone rubber pressure-sensitive adhesive materials described in these documents have low pressure-sensitive adhesive strength, and the pressure-sensitive adhesive strength may be insufficient depending on the application.

Japanese Patent Publication No.54-37907 JP-A 63-22886 JP 2004-189945 A JP 2006-225420 A

  This invention was made in order to improve the said situation, and it aims at providing the addition curable silicone rubber composition which can give a silicone rubber with high adhesiveness, without reducing intensity | strength.

  As a result of intensive studies to achieve the above object, the inventor of the present invention uses a silicone resin that imparts tackiness and a silicone resin that imparts rubber strength, and further uses a crosslinking agent having a specific structure. The present inventors have found a silicone rubber composition that gives a silicone rubber having high rubber strength and high adhesiveness, and has led to the present invention.

（式中、Ｒ³は同一又は異種の非置換又は置換の一価炭化水素基、ｎは３〜３００の整数）
で表される一分子中にケイ素原子に直接結合した水素原子を３個以上含有し、かつ、分子鎖途中にジオルガノシロキサン単位を含有しないオルガノハイドロジェンポリシロキサン：（Ａ）〜（Ｃ）成分の合計１００質量部に対して０．１〜１０質量部、
（Ｅ）付加反応触媒：触媒量
を含有し、硬化後のゴムが表面粘着性を有する付加硬化性シリコーンゴム組成物。
〔２〕
（Ｂ）成分の樹脂質共重合体が実質的にアルケニル基を含有せず、かつ常温で固体であることを特徴とする〔１〕記載の付加硬化性シリコーンゴム組成物。
〔３〕
（Ｃ）成分の樹脂質共重合体のアルケニル基含有量が、０．０００１〜０．００３ｍｏｌ／ｇである〔１〕又は〔２〕記載の付加硬化性シリコーンゴム組成物。
〔４〕
組成物中のＳｉＨ基量とアルケニル基量のモル比（ＳｉＨ基／アルケニル基）が０．３〜２である〔１〕〜〔３〕のいずれかに記載の付加硬化性シリコーンゴム組成物。
〔５〕
組成物中のＳｉＨ基量とアルケニル基量のモル比（ＳｉＨ基／アルケニル基）が０．５〜１である〔４〕記載の付加硬化性シリコーンゴム組成物。
〔６〕
（Ｄ）成分がトリメチルシロキシ基及び／又はジメチルハイドロジェンシロキシ基で末端が封鎖された直鎖状メチルハイドロジェンポリシロキサンである〔１〕〜〔５〕のいずれかに記載の付加硬化性シリコーンゴム組成物。
〔７〕
（Ｄ）成分がヒドロメチルシロキサン単位のみからなる環状メチルハイドロジェンポリシロキサンである〔１〕〜〔５〕のいずれかに記載の付加硬化性シリコーンゴム組成物。
〔８〕
〔１〕〜〔７〕のいずれかに記載の付加硬化性シリコーンゴム組成物を硬化してなる粘着性シリコーンゴム硬化物。 Accordingly, the present invention provides the following addition-curable silicone rubber composition and cured product.
[1]
(A) Alkenyl group-containing organopolysiloxane having an alkenyl group bonded to at least two silicon atoms in one molecule represented by the following average composition formula (II): 10 to 75 parts by mass
R ⁴ _a SiO _{(4-a) / 2} (II)
(In the formula, R ⁴ is the same or different, identical or different, unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and a is a positive number in the range of 1.5 to 2.8. is there.)
(B) R ¹ ₃ SiO _1/2 unit (wherein R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group) and SiO ₂ unit as main components, and R ¹ ₃ SiO _1/2 unit And the SiO ₂ unit [R ¹ ₃ SiO _1/2 / SiO ₂ ] is 0.5 to 1.5, and R ¹ does not contain an alkenyl group or the total amount is 0. Resinous copolymer of less than 0001 mol / g: 20 to 70 parts by mass
(C) R ² ₃ SiO _1/2 units (wherein, R ² is identical or unsubstituted or substituted heterologous monovalent hydrocarbon group) as a main component is SiO ₂ units, R ² ₃ SiO _1/2 units And SiO ₂ unit [R ² ₃ SiO _1/2 / SiO ₂ ] is 0.5 to 1.5, R ² contains an alkenyl group, and the total amount is 0.0001 mol / g or more. Resinous copolymer: 5 to 50 parts by mass,
(However, the total amount of the components (A), (B), and (C) is 100 parts by mass.)
(D) The following general formula (I)

(Wherein R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 3 to 300)
An organohydrogenpolysiloxane containing three or more hydrogen atoms directly bonded to a silicon atom in one molecule represented by the formula and containing no diorganosiloxane unit in the middle of the molecular chain: (A) to (C) components 0.1 to 10 parts by mass with respect to a total of 100 parts by mass,
(E) Addition reaction catalyst: an addition-curable silicone rubber composition containing a catalytic amount, and the cured rubber has surface tackiness.
[2]
The addition-curable silicone rubber composition according to [1], wherein the resinous copolymer of component (B) contains substantially no alkenyl group and is solid at room temperature.
[3]
The addition-curable silicone rubber composition according to [1] or [2], wherein the resinous copolymer of component (C) has an alkenyl group content of 0.0001 to 0.003 mol / g.
[4]
The addition curable silicone rubber composition according to any one of [1] to [3], wherein the molar ratio of the amount of SiH groups to the amount of alkenyl groups (SiH group / alkenyl group) in the composition is 0.3-2.
[5]
[4] The addition-curable silicone rubber composition according to [4], wherein the molar ratio of the amount of SiH groups to the amount of alkenyl groups (SiH group / alkenyl group) in the composition is 0.5 to 1.
[6]
The addition-curable silicone rubber according to any one of [1] to [5], wherein the component (D) is a linear methylhydrogenpolysiloxane having a terminal blocked with a trimethylsiloxy group and / or a dimethylhydrogensiloxy group. Composition.
[7]
(D) The addition-curable silicone rubber composition according to any one of [1] to [5], wherein the component is a cyclic methylhydrogenpolysiloxane composed only of hydromethylsiloxane units.
[8]
[1] A cured adhesive silicone rubber product obtained by curing the addition-curable silicone rubber composition according to any one of [7].

  According to the present invention, an addition-curable silicone rubber composition capable of giving a silicone rubber having high rubber strength and high surface tackiness by combining specific amounts of the components (A) to (E). Can be provided.

Hereinafter, the present invention will be described in more detail.
First, the organopolysiloxane containing an alkenyl group bonded to at least two silicon atoms in one molecule of the component (A) is a main component (base polymer) of the composition, and the organopolysiloxane includes: It is shown by the following average composition formula (II).
R ⁴ _a SiO _{(4-a) / 2} (II)
(In the formula, R ⁴ is the same or different monovalent hydrocarbon group having the same or different carbon number of 1 to 10, preferably 1 to 8, and a is 1.5 to 2.8. The positive number is preferably 1.8 to 2.5, and more preferably 1.95 to 2.05.)

Here, R ⁴ is the same or different unsubstituted or substituted monovalent hydrocarbon group, and usually has 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms bonded to a silicon atom. Specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, etc. Linear, branched or cyclic alkyl groups, phenyl groups, tolyl groups, xylyl groups, aryl groups such as naphthyl groups, aralkyl groups such as benzyl groups, phenylethyl groups, phenylpropyl groups, vinyl groups, allyl groups, propenyls A linear, branched or cyclic alkenyl group such as a group, isopropenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group, etc., or part or all of the hydrogen atoms of these groups may be fluorine, bromine, chlorine Substituted with a halogen atom such as cyano group, etc., such as chloromethyl group, chloropropyl group, bromoethyl group, Li fluoropropyl group, but cyanoethyl group and the like, Preferably, at least 90 mol% of the total R ⁴ is a methyl group.

Further, at least two of R ⁴ must be alkenyl groups (preferably those having 2 to 8 carbon atoms, more preferably 2 to 6 and particularly preferably vinyl groups).
The alkenyl group content in the organopolysiloxane is 1.0 × 10 ⁻⁶ mol / g to 3.0 × 10 ⁻³ mol / g, particularly 1.0 × 10 ⁻⁵ mol / g to 2.0. It is preferable to set it as x10 < ^-3 > mol / g. If the amount of the alkenyl group is less than 1.0 × 10 ⁻⁶ mol / g, the rubber hardness may be too low to form a gel, and if it exceeds 3.0 × 10 ⁻³ mol / g, the crosslinking density Becomes too high, the hardness becomes extremely high, and the elasticity of the rubber may be lost. The alkenyl group may be bonded to the silicon atom at the end of the molecular chain, may be bonded to the silicon atom in the middle of the molecular chain (non-terminal), or may be bonded to both.

The structure of this organopolysiloxane basically has both ends of the molecular chain blocked with triorganosiloxy groups (R ⁴ ₃ SiO _1/2 ) and the main chain is a diorganosiloxane unit (R ⁴ ₂ SiO _2/2). ) Is preferably a linear diorganopolysiloxane consisting of a repeating structure, but partially has a branched or cyclic structure having a _{monoorganosilsesquioxane} unit (R ⁴ SiO _3/2 ) (R ⁴ is as described above).

  Regarding the molecular weight or the degree of polymerization, the average degree of polymerization (number average degree of polymerization, hereinafter the same) is usually 100 to 50,000, preferably 150 to 20,000. If it is less than 100, the cured product may not have a sufficient rubber feeling, and if it is higher than 50,000, the viscosity becomes high and molding may be difficult. Here, the molecular weight or the degree of polymerization can be determined, for example, as the number average molecular weight or number average degree of polymerization in terms of polystyrene in gel permeation chromatography (GPC) analysis using toluene as a developing solvent (hereinafter the same).

Specifically, as the organopolysiloxane of component (A), molecular chain both ends diorganoalkenylsiloxy group-blocked diorganopolysiloxane, molecular chain both ends organodialkenylsiloxy group-blocked diorganopolysiloxane, molecular chain Both ends trialkenylsiloxy group-blocked diorganopolysiloxane, molecular chain both ends triorganosiloxy group-blocked diorganosiloxane / organoalkenylsiloxane copolymer, both ends chain diorganoalkenylsiloxy group-blocked diorganosiloxane / organoalkenylsiloxane Examples of the polymer include a diorganosiloxane / organoalkenylsiloxane copolymer in which one end of a molecular chain is blocked with a diorganoalkenylsiloxy group and the other end is a triorganosiloxy group blocked. Diorganoalkenylsiloxy group-capped diorganopolysiloxane, diorganoalkenylsiloxy group-capped diorganopolysiloxane, diorganosiloxane / organoalkenylsiloxane copolymer with both ends of molecular chain, diorganoalkenylsiloxy group-capped diorganosiloxane / organo with molecular chain An alkenylsiloxane copolymer. The “organo group” in each siloxane is the same as the unsubstituted or substituted monovalent hydrocarbon group other than the aliphatic unsaturated group such as alkenyl group among R ⁴ in the formula (II). Means.

  (A) A component may be used individually by 1 type, or 2 or more types of mixtures from which molecular weight (polymerization degree) and molecular structure differ may be sufficient.

Next, the resinous copolymer of component (B) (that is, a copolymer having a three-dimensional network structure) is a silicone resin that imparts tackiness to the cured product, and includes R ¹ ₃ SiO _1/2 units and SiO ₂ units. Mainly ₂ units. Here, R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, and as the monovalent hydrocarbon group represented by R ¹ Is a straight chain such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, octyl, nonyl, decyl, etc. Branched or cyclic alkyl groups, phenyl groups, tolyl groups, xylyl groups, aryl groups such as naphthyl groups, aralkyl groups such as benzyl groups, phenylethyl groups, phenylpropyl groups, vinyl groups, allyl groups, propenyl groups, Linear, branched or cyclic alkenyl groups such as propenyl group, butenyl group, hexenyl group, cyclohexenyl group, octenyl group, etc., and hydrogen sources of these groups Examples in which part or all of the children are substituted with a halogen atom such as fluorine, bromine or chlorine, a cyano group, and the like, such as a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, and a cyanoethyl group.

The resinous copolymer of the component (B) may be composed of only the above R ¹ ₃ SiO _1/2 unit and SiO ₂ unit, and if necessary, R ¹ ₂ SiO unit or R ¹ SiO _{3 / 2} units (R ¹ above as) as the total amount thereof, with respect to the total copolymer mass, 50% or less, and preferably may comprise from 40% or less, R ¹ ₃ SiO _1/2 The molar ratio [R ¹ ₃ SiO _1/2 / SiO ₂ ] between the unit and the SiO ₂ unit is preferably 0.5 to 1.5, particularly preferably 0.5 to 1.3. Even if this molar ratio is smaller than 0.5 or larger than 1.5, the tackiness is lowered. The resinous copolymer of the component (B) has an alkenyl group content of less than 0.0001 mol / g (that is, less than 0 to 0.0001 mol / g), preferably 0.00005 mol / g. It is more preferable that it is below (that is, 0 to 0.00005 mol / g), and further it does not contain an alkenyl group. When the alkenyl group is less than 0.0001 mol / g, sufficient adhesive strength can be obtained.

  The resinous copolymer of the component (B) may be a liquid that is fluid at room temperature (for example, 25 ° C.) or a solid that is not fluid, but at room temperature in terms of the stickiness of the cured product. Solid ones are preferred. This resinous copolymer can be usually produced by hydrolyzing an appropriate chlorosilane or alkoxysilane by a method well known in the art.

The component (C) resinous copolymer (that is, a copolymer having a three-dimensional network structure) is a silicone resin that imparts rubber strength to a cured product, and includes R ² ₃ SiO _1/2 units and SiO ₂ units. The main component. Here, R ² is the same or different unsubstituted or substituted monovalent hydrocarbon group, preferably having 1 to 10 carbon atoms, particularly 1 to 8 carbon atoms, and the monovalent hydrocarbon group represented by R ² is , Straight chain such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, neopentyl group, hexyl group, cyclohexyl group, octyl group, nonyl group, decyl group, Branched or cyclic alkyl group, aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group, aralkyl group such as benzyl group, phenylethyl group, phenylpropyl group, vinyl group, allyl group, propenyl group, isopropenyl Groups, butenyl groups, hexenyl groups, cyclohexenyl groups, octenyl groups, etc., linear, branched or cyclic alkenyl groups, and hydrogen atoms of these groups Are substituted with a halogen atom such as fluorine, bromine or chlorine, a cyano group, or the like, such as a chloromethyl group, a chloropropyl group, a bromoethyl group, a trifluoropropyl group, or a cyanoethyl group.

The resinous copolymer of the component (C) may be composed only of the R ² ₃ SiO _1/2 unit and the SiO ₂ unit, and if necessary, the R ² ₂ SiO unit or R ² SiO _{3. / 2} units (as for R ² above) as the total amount of these with respect to the total copolymer mass, 50% or less, and preferably may comprise from 40% or less, R ² ₃ SiO _1/2 The molar ratio [R ² ₃ SiO _1/2 / SiO ₂ ] between the unit and the SiO ₂ unit is preferably 0.5 to 1.5, particularly preferably 0.5 to 1.3. Even if this molar ratio is smaller than 0.5 or larger than 1.5, sufficient rubber hardness / strength cannot be obtained. Further, the content of the alkenyl group in the resinous copolymer of component (C) is 0.0001 mol / g or more, preferably 0.0001 to 0.003 mol / g, more preferably 0.0002 to 0. The range is 0.002 mol / g. When the content of the alkenyl group is 0.0001 mol / g or more, sufficient rubber physical properties are obtained, and when it is more than 0.003 mol / g, the hardness becomes too high and the adhesive force may be lowered.

  In addition, the resinous copolymer of the component (C) is a liquid that has a fluidity at room temperature (25 ° C.) (for example, 10 mPa · s or more, preferably 50 mPa · s or more) that is not solid. It may be a thing. Here, this viscosity value is a value measured by a rotational viscometer (for example, BL type, BH type, BS type, cone plate type, etc.). This resinous copolymer can be usually produced by hydrolyzing an appropriate chlorosilane or alkoxysilane by a method well known in the art.

  The content of the alkenyl group in the total of the resinous copolymer of the component (B) and the resinous copolymer of the component (C) is 0.00001 to 0 in terms of rubber properties and adhesiveness. 0.002 mol / g, particularly 0.0005 to 0.001 mol / g is preferable.

  The number average molecular weight of the resinous copolymer of component (B) and the resinous copolymer of component (C) is about 400 to 100,000, particularly 500 to 30,000, especially about 800 to 8,000. It is preferable. If it is less than 400, sufficient adhesive strength or reinforcing effect may not be obtained. If it is greater than 100,000, the composition may have too high a viscosity and molding may be difficult, or stable production may not be possible. .

  Here, the compounding amount of the component (A) is 10 to 75 parts by mass, particularly 20 to 70 parts by mass, and the compounding amount of the component (B) is 20 to 70 parts by mass, particularly 25 to 60 parts by mass. The amount of component (C) is 5 to 50 parts by weight, particularly 10 to 40 parts by weight, and the total amount thereof is 100 parts by weight. If the amount of component (A) is too small, the rubber elasticity will be lost and brittle, and if it is too large, the tackiness and strength will be insufficient. (B) If there are too few components, sufficient adhesiveness will not be acquired, but if too large, adhesiveness will also fall and rubber physical properties will fall remarkably. On the other hand, if the amount of the component (C) is too small, sufficient rubber properties cannot be obtained.

（式中、Ｒ³は同一又は異種の非置換又は置換の一価炭化水素基、ｎは３〜３００の整数）
で表される一分子中に少なくとも３個（通常３〜２００個）、好ましくは３〜１００個、より好ましくは３〜５０個のケイ素原子結合水素原子を有するものが好適に用いられる。ｎが３未満であると十分な架橋構造が構築できず、硬化物のゴム強度に悪影響を与える。この場合、分子鎖末端はトリオルガノシロキシ基（−ＯＳｉＲ³ ₃）又はジオルガノハイドロジェンシロキシ基（−ＯＳｉＨＲ³ ₂）で封鎖されたものが好ましい。 The organohydrogenpolysiloxane having three or more hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule of component (D) and not containing a diorganosiloxane unit in the middle of the molecular chain is an SiH group in the molecule. Acts as a curing agent for curing the composition by crosslinking with an alkenyl group bonded to a silicon atom in the components (A), (B) and (C) by a hydrosilyl addition reaction. The organohydrogenpolysiloxane of component (D) has the following general formula (I)

(Wherein R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 3 to 300)
One having at least 3 (usually 3 to 200), preferably 3 to 100, more preferably 3 to 50 silicon atom-bonded hydrogen atoms in one molecule represented by is suitably used. When n is less than 3, a sufficient cross-linked structure cannot be constructed, which adversely affects the rubber strength of the cured product. In this case, what is the molecular chain end blocked with triorganosiloxy groups (-OSiR ³ ₃₎ or diorganohydrogensiloxy group (-OSiHR ³ ₂₎ are preferred.

Here, examples of the monovalent hydrocarbon group for R ³ include the same groups as those exemplified for R ¹ , but those having no aliphatic unsaturated bond are preferred. The molecular structure of the organohydrogenpolysiloxane is preferably a linear or cyclic structure. In this case, the number (or degree of polymerization) of silicon atoms in one molecule is preferably 3 to 200, particularly 3 to 100 at room temperature (25 ° C.).

  The organohydrogenpolysiloxane of the component (D) is one having no diorganosiloxane unit in the middle of the molecular chain, trimethylsiloxy group-blocked methylhydrogenpolysiloxane at both ends, and dimethylhydrogensiloxy group-blocked methyl at both ends. Examples thereof include hydrogen polysiloxane and cyclic methyl hydrogen polysiloxane. In the case of an organohydrogenpolysiloxane containing a diorganosiloxy unit in the middle of the molecular chain, it becomes a rubber having low adhesiveness.

  The compounding quantity of this organohydrogenpolysiloxane is 0.1-10 mass parts with respect to a total of 100 mass parts of (A), (B), and (C) component, especially 0.1-8 mass parts. If the blending amount is less than 0.1 parts by mass, sufficient rubber strength cannot be obtained and the composition does not cure. Moreover, when it exceeds 10 mass parts, adhesive force will fall. Further, the organohydrogenpolysiloxane of component (D) was bonded to the silicon atom in component (D) relative to the alkenyl group bonded to the silicon atom contained in components (A), (B) and (C). When blended so that the amount of hydrogen atoms (SiH groups) is in a molar ratio, preferably 0.3 to 2 mol / mol, more preferably 0.5 to 1 mol / mol, a silicone rubber with high adhesion can be obtained.

  As an addition reaction catalyst for component (E), platinum black, platinum chloride, chloroplatinic acid, a reaction product of chloroplatinic acid and a monohydric alcohol, a complex of chloroplatinic acid and olefins, chloroplatinic acid and vinyl Examples include complexes with siloxanes, platinum-based catalysts such as platinum bisacetoacetate, palladium-based catalysts, and rhodium-based catalysts. In addition, the compounding quantity of this addition reaction catalyst can be made into a catalyst quantity, and is 0.5-1,000 ppm with respect to the total amount of (A)-(D) component as a platinum group metal normally, Especially about 1-500 ppm. It is. If the blending amount is less than 0.5 ppm, the addition reaction may not be sufficiently accelerated and curing may be insufficient. If the blending amount is more than 1,000 ppm, the effect on the reactivity is small and uneconomical.

  Other components include fumed silica, precipitated silica, quartz powder, diatomaceous earth, calcium carbonate, conductive agents such as carbon black, conductive zinc white, metal powder, iron oxide, oxidation as required. A heat-resistant agent such as cerium may be blended. Furthermore, it is optional to add hydrosilylation reaction control agents such as nitrogen-containing compounds, acetylene compounds, phosphorus compounds, nitrile compounds, carboxylates, tin compounds, mercury compounds, sulfur compounds, adhesion imparting agents, thixotropic properties imparting agents, etc. It is said.

  As a method for molding and curing the addition-curable silicone rubber composition, a conventional method can be adopted. However, as a molding method, an optimal means suitable for the purpose is selected from injection molding, transfer molding, injection molding, compression molding, and the like. It is possible. As curing conditions, heat treatment (primary vulcanization) conditions at 40 to 230 ° C. for about 3 seconds to 160 minutes may be employed. Furthermore, secondary vulcanization (post cure) may be performed at 40 to 230 ° C. for about 10 minutes to 24 hours as necessary.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to a following example. In addition, a part shows a mass part by the following example. Moreover, an average degree of polymerization shows the number average degree of polymerization of polystyrene conversion in the gel permeation chromatography (GPC) analysis which used toluene as the developing solvent.

[Example 1]
45 parts of dimethylpolysiloxane (A1) having an average degree of polymerization of 300 with both ends of the molecular chain blocked with dimethylvinylsiloxy groups, solid (CH ₃ ) ₃ SiO _1/2 units and SiO ₂ at room temperature (25 ° C.) Resinous copolymer consisting of units (B1) [(CH ₃ ) ₃ SiO _1/2 units / SiO ₂ units = 0.75 (molar ratio), Mn = 2,500] 35 parts, (CH ₃ ) Resinous copolymer (C1) [((CH ₃ ) ₃ SiO _1/2 unit + CH comprising ₃ SiO _1/2 units, CH ₂ = CH (CH ₃ ) ₂ SiO _1/2 units and SiO ₂ units ₂ = CH (CH ₃ ) ₂ SiO _1/2 unit) / SiO ₂ unit = 0.9 (molar ratio), vinyl group content = 0.0008 mol / g, Mn = 3,700] 20 parts are mixed, Silicone rubber base A was obtained. Methyl hydrogen polysiloxane (D1) having 100 parts of this silicone rubber base A blocked with trimethylsiloxy groups at both ends as a cross-linking agent, having a SiH group in the side chain, and containing no diorganosiloxane unit in the middle of the molecular chain. ) (Polymerization degree 10, SiH group amount 0.0125 mol / g molecular chain both ends trimethylsiloxy group blocked methyl hydrogen polysiloxane) 1.2 parts (SiH group / vinyl group = 0.77 mol / mol), reaction control agent Then, 0.05 part of ethynylcyclohexanol was added and stirred for 15 minutes to obtain a silicone rubber composition. This silicone rubber composition is mixed with 0.1 part of a platinum catalyst (Pt concentration 1% by mass), press cured at 120 ° C./10 minutes, and then post cured at 200 ° C. for 4 hours in an oven to obtain a cured product. Obtained. The results of measurement of hardness (durometer A), tensile strength, and elongation at break of this cured product based on JIS K6249 are shown in Table 1, and surface adhesive strength by a texture analyzer (manufactured by Eiko Seiki Co., Ltd.) is also shown. The measurement results are shown in Table 1.

[Example 2]
Methyl hydrogen poly having 100 parts of silicone rubber base A of Example 1 having both ends of a molecular chain blocked with trimethylsiloxy groups as crosslinkers, SiH groups in side chains, and no diorganosiloxane unit in the middle of the molecular chain 1.1 parts (SiH group / vinyl group = 0.88 mol / mol) of siloxane (D2) (polymerization degree 40, trimethylsiloxy group-blocked methylhydrogenpolysiloxane with molecular chain at both ends of 0.0156 mol / g), As a reaction control agent, 0.05 part of ethynylcyclohexanol was added and stirred for 15 minutes to obtain a silicone rubber composition. This silicone rubber composition is mixed with 0.1 part of a platinum catalyst (Pt concentration 1% by mass), press cured at 120 ° C./10 minutes, and then post cured at 200 ° C. for 4 hours in an oven to obtain a cured product. Obtained. The results of measurement of hardness (durometer A), tensile strength, and elongation at break of this cured product based on JIS K6249 are shown in Table 1, and surface adhesive strength by a texture analyzer (manufactured by Eiko Seiki Co., Ltd.) is also shown. The measurement results are shown in Table 1.

[Example 3]
To 100 parts of the silicone rubber base A of Example 1, 1,3,5,7-tetrahydrotetramethylcyclotetrasiloxane (D3) (cyclic hydrogen tetramethyl methylhydrogen poly having a SiH group content of 0.0167 mol / g was used as a crosslinking agent. Siloxane) 0.81 part (SiH group / vinyl group = 0.70 mol / mol) and 0.05 part of ethynylcyclohexanol as a reaction control agent were added and stirred for 15 minutes to obtain a silicone rubber composition. This silicone rubber composition is mixed with 0.1 part of a platinum catalyst (Pt concentration 1% by mass), press cured at 120 ° C./10 minutes, and then post cured at 200 ° C. for 4 hours in an oven to obtain a cured product. Obtained. The results of measurement of hardness (durometer A), tensile strength, and elongation at break of this cured product based on JIS K6249 are shown in Table 1, and surface adhesive strength by a texture analyzer (manufactured by Eiko Seiki Co., Ltd.) is also shown. The measurement results are shown in Table 1.

[Example 4]
To 100 parts of the silicone rubber base A of Example 1, 7 parts of hydrophobized fumed silica (N-Aerosil Co., Ltd., R-972) having a specific surface area of 110 m ² / g as reinforcing silica was added, After mixing for 30 minutes with a planetary mixer, it was passed once through three rolls. Subsequently, 1.2 parts of methyl hydrogen polysiloxane (D1) of Example 1 (SiH group / vinyl group = 0.77 mol / mol) as a crosslinking agent and 0.05 part of ethynylcyclohexanol as a reaction control agent were added, The mixture was stirred for 15 minutes to obtain a silicone rubber composition. This silicone rubber composition is mixed with 0.1 part of a platinum catalyst (Pt concentration 1% by mass), press cured at 120 ° C./10 minutes, and then post cured at 200 ° C. for 4 hours in an oven to obtain a cured product. Obtained. The results of measurement of hardness (durometer A), tensile strength, and elongation at break of this cured product based on JIS K6249 are shown in Table 1, and surface adhesive strength by a texture analyzer (manufactured by Eiko Seiki Co., Ltd.) is also shown. The measurement results are shown in Table 1.

[Comparative Example 1]
Methyl hydrogen polysiloxane (100 parts of silicone rubber base A of Example 1) having both ends of a molecular chain blocked with a trimethylsiloxy group as a crosslinking agent, a side chain having a SiH group, and a dimethylsiloxane unit in the middle of the molecular chain ( D4) 1.4 parts (SiH group / vinyl group = 0.77 mol / polymer of a dimethylsiloxane / methylhydrogensiloxane copolymer blocked with a trimethylsiloxy group at both ends of a molecular chain having a degree of polymerization of 54 and a SiH group amount of 0.0108 mol / g) mol), 0.05 part of ethynylcyclohexanol was added as a reaction control agent and stirred for 15 minutes to obtain a silicone rubber composition. This silicone rubber composition is mixed with 0.1 part of a platinum catalyst (Pt concentration 1% by mass), press cured at 120 ° C./10 minutes, and then post cured at 200 ° C. for 4 hours in an oven to obtain a cured product. Obtained. The results of measurement of hardness (durometer A), tensile strength, and elongation at break of this cured product based on JIS K6249 are shown in Table 1, and surface adhesive strength by a texture analyzer (manufactured by Eiko Seiki Co., Ltd.) is also shown. The measurement results are shown in Table 1.

[Comparative Example 2]
Methyl hydrogen poly having 100 parts of silicone rubber base A in Example 1 having both ends of a molecular chain blocked with dimethylhydrogensiloxy groups as crosslinkers, SiH groups in side chains, and dimethylsiloxane units in the middle of the molecular chain Siloxane (D5) (polymerization degree 17, dimethylhydrogensiloxy group-blocked dimethylsiloxane / methylhydrogensiloxane copolymer having a SiH group content of 0.0053 mol / g) 2.6 parts (SiH group / vinyl group = 0.70 mol / mol), 0.05 part of ethynylcyclohexanol was added as a reaction control agent, and stirred for 15 minutes to obtain a silicone rubber composition. This silicone rubber composition is mixed with 0.1 part of a platinum catalyst (Pt concentration 1% by mass), press cured at 120 ° C./10 minutes, and then post cured at 200 ° C. for 4 hours in an oven to obtain a cured product. Obtained. The results of measurement of hardness (durometer A), tensile strength, and elongation at break of this cured product based on JIS K6249 are shown in Table 1, and surface adhesive strength by a texture analyzer (manufactured by Eiko Seiki Co., Ltd.) is also shown. The measurement results are shown in Table 1.

[Comparative Example 3]
To 100 parts of the silicone rubber base A of Example 1, 7 parts of hydrophobized fumed silica (N-Aerosil Co., Ltd., R-972) having a specific surface area of 110 m ² / g as reinforcing silica was added, After mixing for 30 minutes with a planetary mixer, it was passed once through three rolls. Subsequently, 1.4 parts of methyl hydrogen polysiloxane (D4) of Comparative Example 1 (SiH group / vinyl group = 0.77 mol / mol) as a crosslinking agent and 0.05 part of ethynylcyclohexanol as a reaction control agent were added, The mixture was stirred for 15 minutes to obtain a silicone rubber composition. This silicone rubber composition is mixed with 0.1 part of a platinum catalyst (Pt concentration 1% by mass), press cured at 120 ° C./10 minutes, and then post cured at 200 ° C. for 4 hours in an oven to obtain a cured product. Obtained. The results of measurement of hardness (durometer A), tensile strength, and elongation at break of this cured product based on JIS K6249 are shown in Table 1, and surface adhesive strength by a texture analyzer (manufactured by Eiko Seiki Co., Ltd.) is also shown. The measurement results are shown in Table 1.

  The surface-adhesive silicone rubber obtained by using the addition-curable silicone rubber composition of the present invention is used for fixing various parts and tools, for example, fixing medical instruments in hospitals, restaurants, party venues, etc. Can be used for fixing tableware. In addition, it can be used as an adhesive fixing member in the production of various electronic components such as mounting of chip-type electronic components such as capacitors, actuators and inductors and flexible printed boards.

Claims (8)

(A) Alkenyl group-containing organopolysiloxane having an alkenyl group bonded to at least two silicon atoms in one molecule represented by the following average composition formula (II): 10 to 75 parts by mass
R ⁴ _a SiO _{(4-a) / 2} (II)
(In the formula, R ⁴ is the same or different, identical or different, unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, and a is a positive number in the range of 1.5 to 2.8. is there.)
(B) R ¹ ₃ SiO _1/2 unit (wherein R ¹ is the same or different unsubstituted or substituted monovalent hydrocarbon group) and SiO ₂ unit as main components, and R ¹ ₃ SiO _1/2 unit And the SiO ₂ unit [R ¹ ₃ SiO _1/2 / SiO ₂ ] is 0.5 to 1.5, and R ¹ does not contain an alkenyl group or the total amount is 0. Resinous copolymer of less than 0001 mol / g: 20 to 70 parts by mass
(C) R ² ₃ SiO _1/2 units (wherein, R ² is identical or unsubstituted or substituted heterologous monovalent hydrocarbon group) as a main component is SiO ₂ units, R ² ₃ SiO _1/2 units And SiO ₂ unit [R ² ₃ SiO _1/2 / SiO ₂ ] is 0.5 to 1.5, R ² contains an alkenyl group, and the total amount is 0.0001 mol / g or more. Resinous copolymer: 5 to 50 parts by mass,
(However, the total amount of the components (A), (B), and (C) is 100 parts by mass.)
(D) The following general formula (I)

(Wherein R ³ is the same or different unsubstituted or substituted monovalent hydrocarbon group, and n is an integer of 3 to 300)
An organohydrogenpolysiloxane containing three or more hydrogen atoms directly bonded to a silicon atom in one molecule represented by the formula and containing no diorganosiloxane unit in the middle of the molecular chain: (A) to (C) components 0.1 to 10 parts by mass with respect to a total of 100 parts by mass,
(E) Addition reaction catalyst: an addition-curable silicone rubber composition containing a catalytic amount, and the cured rubber has surface tackiness.   The addition-curable silicone rubber composition according to claim 1, wherein the resinous copolymer of component (B) contains substantially no alkenyl group and is solid at room temperature.   The addition curable silicone rubber composition according to claim 1 or 2, wherein the resinous copolymer of component (C) has an alkenyl group content of 0.0001 to 0.003 mol / g.   The addition-curable silicone rubber composition according to any one of claims 1 to 3, wherein the molar ratio of the amount of SiH groups to the amount of alkenyl groups (SiH group / alkenyl group) in the composition is 0.3-2.   The addition-curable silicone rubber composition according to claim 4, wherein the molar ratio of the amount of SiH groups to the amount of alkenyl groups (SiH group / alkenyl group) in the composition is 0.5-1.   The addition-curable silicone rubber according to any one of claims 1 to 5, wherein the component (D) is a linear methylhydrogen polysiloxane having a terminal blocked with a trimethylsiloxy group and / or a dimethylhydrogensiloxy group. Composition.   The addition-curable silicone rubber composition according to any one of claims 1 to 5, wherein the component (D) is a cyclic methyl hydrogen polysiloxane composed only of hydromethylsiloxane units.   A pressure-sensitive adhesive silicone rubber cured product obtained by curing the addition-curable silicone rubber composition according to claim 1.