Mixing type silicone rubber compound, mixing type silicone rubber composition and preparation method of mixing type silicone rubber composition

Abstract

The present invention provides a millable silicone rubber compound comprising: (A) an organopolysiloxane raw rubber; (B) a reinforced silica having a specific surface area of 50-450 m2 / g; (C) a partial hydrolysate of an organoalkoxysilane represented by general formula (1); and (D) one or more condensation reaction catalysts selected from the following (D1)-(D3): (D1) an amine compound that has a boiling point of 30-60 DEG C at 1013 hPa and is liquid at 25 DEG C; (D2) a hexaorganodisilazane represented by general formula (2); and (D3) 1.0-30.0 mass% of ammonia water. As a result, provided are: a millable silicone rubber composite having high plasticity even in millable silicone rubber composites having relatively low hardness; a millable silicone rubber composition; and a method for producing the millable silicone rubber composition. RSi (OR1) 3 (1) R23SiNHSiR23 (2)

Description

Technical Field

[0001] The invention relates to a kneadable silicone rubber compound, a kneadable silicone rubber composition and a method for preparing the kneadable silicone rubber composition. Background Art

[0002] Silicone rubber has excellent weather resistance, electrical properties, low compression set, heat resistance, cold resistance and other properties, and is widely used in various fields such as electrical appliances, automobiles, construction, medical treatment, and food. The demand for silicone rubber is increasing day by day, and it is expected to develop a silicone rubber with further improved properties. These silicone rubbers are usually used in the form of a kneading type silicone rubber compound containing a high degree of polymerization organic polysiloxane raw rubber and a reinforcing filler, and a kneading type silicone rubber composition in which a curing agent is mixed in the compound. The kneading type silicone rubber compound and silicone rubber composition are prepared by mixing a reinforcing filler or various dispersants in the raw polymer using a kneading device such as a kneader or a double-roll mill.

[0003] As described above, in order to prepare a kneadable silicone rubber compound, it is necessary to knead a reinforcing filler such as fumed silica in an organopolysiloxane. At this time, a surface treatment agent for the reinforcing filler called a dispersant (wetter) is used. Usually, when a reinforcing filler such as silica is dispersed in an organopolysiloxane, an organosilane or siloxane having a silanol group is used as a surface treatment agent. If the amount of the surface treatment agent is too much, the plasticity of the silicone rubber compound is reduced, and the plasticity of the silicone rubber composition is also reduced. If such a composition is used, the following problems may occur: for example, according to a molding method such as extrusion molding, the uncured molded product cannot withstand its own weight and deforms, and becomes a defective product. In addition, there is a disadvantage that a sticky feeling will be generated on the surface of the silicone rubber composition, thereby deteriorating the processability. On the contrary, if the amount of the surface treatment agent added is insufficient, there is a problem that although the plasticity is increased, the shrinkage curing (crepe hardening) called reverse plasticization (reverseplasticization) will become larger.

[0004] In order to solve the above-mentioned technical problems, the addition of resin is recorded in Patent Document 1. In addition, Patent Document 2 records that the plasticity can be increased by adding a polycyclic aromatic compound having two or more phenyl groups. However, the problem of reverse plasticization is not recorded, and the additives are expensive. In addition, although Patent Document 3 records that the reverse plasticization can be suppressed by heating the silicone rubber compound at 200-250°C for 4-12 hours, it is not economical. Patent Document 4 reports the addition of a catalyst for the condensation reaction of an organic metal compound selected from an organic titanium compound, an organic zirconium compound and an organic aluminum compound, and the silanol is condensed by heat treatment to increase the plasticity. Although this method is indeed effective in increasing the plasticity, it is difficult to stably obtain the preferred plasticity of the silicone rubber compound.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 06-256658

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 05-065415

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 07-133356

[0010] Patent Document 4: Japanese Patent Application Publication No. 2014-109014 Summary of the invention

[0011] 1. Technical issues to be resolved

[0012] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a kneadable silicone rubber compound, a kneadable silicone rubber composition, and a method for preparing a kneadable silicone rubber composition having high plasticity even in a kneadable silicone rubber compound having a relatively low hardness.

[0013] (II) Technical solution

[0014] In order to solve the above technical problems, the present invention provides a mixing type silicone rubber compound, which comprises:

[0015] 100 parts by mass of (A) an organopolysiloxane raw rubber having two or more alkenyl groups bonded to silicon atoms in one molecule and an average degree of polymerization of 1,000 to 100,000;

[0016] 5 to 100 parts by mass of (B) reinforcing silica, the specific surface area of ​​which based on the BET adsorption method is 50 to 450 m 2 / g;

[0017] 0.1 to 20 parts by mass of (C) a partial hydrolyzate of an organoalkoxysilane represented by the following general formula (1),

[0018] RSi(OR 1 )3(1)

[0019] In formula (1), R is a monovalent hydrocarbon group having 1 to 12 carbon atoms, 1 represents an alkyl group having 1 to 4 carbon atoms; and

[0020] (D) one or more condensation reaction catalysts selected from the group consisting of (D1) to (D3):

[0021] 0.0001 to 0.1 parts by mass of (D1) an amine compound having a boiling point of 30 to 60° C. at 1013 hPa and being liquid at 25° C.;

[0022] 0.001 to 1 parts by mass of (D2) hexaorganodisilazane represented by the following general formula (2),

[0023] R 2 3SiNHSiR 2 3(2)

[0024] In formula (2), R 2 are independently an alkyl group having 1 to 12 carbon atoms;

[0025] 0.001 to 1 parts by mass of (D3) 1.0 to 30.0% by mass of aqueous ammonia.

[0026] Such a kneadable silicone rubber compound has relatively high plasticity even among kneadable silicone rubber compounds having relatively low hardness.

[0027] In the present invention, it is preferred that the R and R 1 Each of the following groups is independently selected from the group consisting of a methyl group, an ethyl group, and a propyl group.

[0028] With such a kneadable silicone rubber compound, the effects of the present invention can be further exerted.

[0029] Furthermore, the present invention provides a kneadable silicone rubber composition comprising a kneaded product obtained by kneading the kneadable silicone rubber compound described above and (E) a curing agent.

[0030] Such a kneadable silicone rubber composition has high plasticity even among kneadable silicone rubber compounds having relatively low hardness.

[0031] In this case, the component (E) is preferably a curing agent for a hydrosilylation reaction consisting of a combination of an organohydrogenpolysiloxane and a hydrosilylation catalyst.

[0032] Such a component (E) is suitable because the kneaded product of the kneadable silicone rubber compound of the present invention contains less impurities that inhibit addition curing.

[0033] In this case, the component (E) may be an organic peroxide.

[0034] Such a curing agent can also be used in the kneadable silicone rubber composition of the present invention.

[0035] In addition, the present invention provides a method for preparing a kneadable silicone rubber composition, which comprises kneading the kneadable silicone rubber compound described above, performing surface treatment of the component (B) with the component (C) in the presence of the component (D) as a catalyst, removing the component (D) by stirring heat, and then adding a curing agent (E).

[0036] According to such a method for preparing a kneadable silicone rubber composition, it is possible to prepare a kneadable silicone rubber composition having high plasticity even in a kneadable silicone rubber compound having a relatively low hardness.

[0037] In this case, it is preferred to use, as the component (E), a curing agent for a hydrosilylation reaction consisting of a combination of an organohydrogenpolysiloxane and a hydrosilylation catalyst, or an organic peroxide.

[0038] Such a curing agent can be used in the method for preparing the kneadable silicone rubber composition of the present invention.

[0039] (III) Beneficial effects

[0040] According to the method of the present invention, a kneadable silicone rubber compound, a kneadable silicone rubber composition, and a method for preparing a kneadable silicone rubber composition can be provided, which can obtain high plasticity even in a kneadable silicone rubber compound with relatively low hardness. DETAILED DESCRIPTION

[0041] As described above, it is desired to develop a kneadable silicone rubber compound, a kneadable silicone rubber composition, and a method for producing the kneadable silicone rubber composition, which have high plasticity even among kneadable silicone rubber compounds having relatively low hardness.

[0042] The inventors of the present application have repeatedly conducted in-depth studies on the above-mentioned technical problems and have found that a kneadable silicone rubber composite comprising (A) a specific organic polysiloxane raw rubber, (B) a reinforcing silica having a specific specific surface area, (C) a partial hydrolyzate of an organic alkoxysilane having a specific structure, and (D) a specific condensation reaction catalyst can solve the above-mentioned technical problems, thereby completing the present invention.

[0043] That is, the present invention is a kneading type silicone rubber compound, which comprises:

[0044] 100 parts by mass of (A) an organopolysiloxane raw rubber having two or more alkenyl groups bonded to silicon atoms in one molecule and an average degree of polymerization of 1,000 to 100,000;

[0045] 5 to 100 parts by mass of (B) reinforcing silica, the specific surface area of ​​which based on the BET adsorption method is 50 to 450 m 2 / g;

[0046] 0.1 to 20 parts by mass of (C) a partial hydrolyzate of an organoalkoxysilane represented by the following general formula (1),

[0047] RSi(OR 1 )3(1)

[0048] In formula (1), R is a monovalent hydrocarbon group having 1 to 12 carbon atoms, 1 represents an alkyl group having 1 to 4 carbon atoms; and

[0049] (D) one or more condensation reaction catalysts selected from the group consisting of (D1) to (D3):

[0050] 0.0001 to 0.1 parts by mass of an amine compound (D1) having a boiling point of 30 to 60° C. at 1013 hPa and being liquid at 25° C.;

[0051] 0.001 to 1 parts by mass of (D2) hexaorganodisilazane represented by the following general formula (2),

[0052] R 2 3SiNHSiR 2 3(2)

[0053] In formula (2), R 2 are independently an alkyl group having 1 to 12 carbon atoms;

[0054] 0.001 to 1 parts by mass of (D3) 1.0 to 30.0% by mass of aqueous ammonia.

[0055] Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

[0056] [Mixable silicone rubber compound]

[0057] The millable silicone rubber compound of the present invention comprises:

[0058] 100 parts by mass of (A) an organopolysiloxane raw rubber having two or more alkenyl groups bonded to silicon atoms in one molecule and an average degree of polymerization of 1,000 to 100,000;

[0059] 5 to 100 parts by mass of (B) reinforcing silica, the specific surface area of ​​which based on the BET adsorption method is 50 to 450 m 2 / g;

[0060] 0.1 to 20 parts by mass of (C) a partial hydrolyzate of an organoalkoxysilane represented by the following general formula (1),

[0061] RSi(OR 1 )3(1)

[0062] In formula (1), R is a monovalent hydrocarbon group having 1 to 12 carbon atoms, 1 represents an alkyl group having 1 to 4 carbon atoms; and

[0063] (D) one or more condensation reaction catalysts selected from the group consisting of (D1) to (D3):

[0064] 0.0001 to 0.1 parts by mass of (D1) an amine compound having a boiling point of 30 to 60° C. at 1013 hPa and being liquid at 25° C.;

[0065] 0.001 to 1 parts by mass of (D2) hexaorganodisilazane represented by the following general formula (2),

[0066] R 2 3SiNHSiR 2 3(2)

[0067] In formula (2), R 2 are independently an alkyl group having 1 to 12 carbon atoms;

[0068] 0.001 to 1 parts by mass of (D3) 1.0 to 30.0% by mass of aqueous ammonia.

[0069] Hereinafter, each component will be described in detail.

[0070] -(A)Component-

[0071] In the present invention, the component (A) is an organopolysiloxane gum having two or more alkenyl groups bonded to silicon atoms in one molecule and an average degree of polymerization of 1,000 to 100,000.

[0072] As the alkenyl group, an alkenyl group having 2 to 8 carbon atoms is preferred, and an alkenyl group having 2 to 6 carbon atoms is more preferred. Specifically, vinyl, allyl, butenyl, pentenyl, hexenyl, cyclohexenyl, etc. are listed. Among them, vinyl is preferred.

[0073] As substituents other than the alkenyl group, monovalent hydrocarbon groups having 1 to 12 carbon atoms, particularly monovalent hydrocarbon groups having 1 to 8 carbon atoms, can be cited. Specifically, alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, and octyl, cycloalkyl groups such as cyclopentyl and cyclohexyl, aryl groups such as phenyl and tolyl, aralkyl groups such as benzyl and 2-phenylethyl, etc. can be cited. In addition, fluoroalkyl groups in which a part of the alkyl group is substituted with fluorine atoms can also be used. Among them, methyl and phenyl are preferred, and methyl is particularly preferred.

[0074] In addition, the above-mentioned (A) component is characterized in that it has more than 2 alkenyl groups bonded to silicon atoms in 1 molecule, preferably 2 to 50 alkenyl groups, and more preferably 2 to 20 alkenyl groups. Among them, it is particularly preferred to have a vinyl group. At this time, in all siloxane units of the organopolysiloxane, preferably 0.01 to 20 mol% are siloxane units with alkenyl groups, and particularly preferably 0.02 to 10 mol% are siloxane units with alkenyl groups. In addition, the alkenyl group can be bonded to a silicon atom at the end of the molecular chain, or to a silicon atom in the middle of the molecular chain (non-terminal of the molecular chain), or it can be these two cases, preferably at least bonded to a silicon atom at the end of the molecular chain.

[0075] Furthermore, among all the siloxane units in the organopolysiloxane, it is desirable that 80 mol % or more, preferably 90 mol % or more, more preferably 95 mol % or more, and further preferably all the siloxane units other than the siloxane units having an alkenyl group are dialkylsiloxy groups, and it is particularly desirable that 80 mol % or more, preferably 90 mol % or more, more preferably 95 mol % or more, and further preferably all the siloxane units other than the siloxane units having an alkenyl group are dimethylsiloxy groups.

[0076] The molecular structure of the organopolysiloxane as the component (A) is preferably a linear structure or a linear structure having a partial branched structure. Specifically, the repeating structure of the diorganosiloxane unit constituting the main chain of the organopolysiloxane is preferably composed of only repeating dimethylsiloxane units, or a diphenylsiloxane unit, a methylphenylsiloxane unit, a methylvinylsiloxane unit, a methyl-3,3,3-trifluoropropylsiloxane unit or the like is introduced as a part thereof.

[0077] Furthermore, both ends of the molecular chain are preferably capped with a group selected from, for example, a trimethylsiloxane group, a dimethylphenylsiloxane group, a vinyldimethylsiloxane group, a divinylmethylsiloxane group, a trivinylsiloxane group, and particularly preferably with a vinyldimethylsiloxy group.

[0078] Examples of the organopolysiloxane of the component (A) include methylvinylpolysiloxane, methylphenylvinylpolysiloxane, and methyltrifluoropropylvinylpolysiloxane.

[0079] Such an organopolysiloxane can be obtained, for example, by (co)hydrolysis and condensation of one or more organohalogenated silanes, or by ring-opening polymerization of a cyclic polysiloxane (such as a trimer or tetramer of siloxane) using a basic or acidic catalyst.

[0080] In addition, the average degree of polymerization of the above-mentioned organopolysiloxane is 1,000~100,000, preferably 2,000~50,000, more preferably 2,500~30,000, and particularly preferably 3,000~20,000. In addition, the properties of the organopolysiloxane are so-called raw gel (non-liquid) without self-fluidity at room temperature (25°C). If the average degree of polymerization is too small, problems such as roller adhesion will occur when the composite is made, and the roller workability will deteriorate. If the average degree of polymerization is too large, when preparing the composite, the dispersion of the reinforcing silica deteriorates, or the kneading time becomes longer, and in the worst case, it may not be possible to obtain the target composite. In addition, the degree of polymerization can be measured as a weight average degree of polymerization based on polystyrene conversion analyzed by gel permeation chromatography (GPC).

[0081] The component (A) may be used alone or as a mixture of two or more components having different molecular weights (polymerization degrees) or molecular structures.

[0082] -(B) Component-

[0083] The reinforcing silica of the component (B) is a filler added to obtain a kneadable silicone rubber composition having excellent mechanical strength. For this purpose, the specific surface area (BET adsorption method) needs to be 50 to 450 m 2 / g, preferably 100~450m 2 / g, more preferably 100 to 300 m 2 / g. If the specific surface area is less than 50m 2 / g, the mechanical strength of the cured product will be reduced, so it is not preferred. In addition, if the specific surface area is greater than 450m 2 / g, the dispersion of reinforcing silica becomes poor or the kneading time becomes long during the preparation of the composite. In the worst case, the target composite may not be obtained. 2 When the reinforcing silica is less than 1.5 g / cm2, the hardness of the cured product becomes very high, so the possibility of deterioration of flexibility also increases.

[0084] As such reinforcing silica, for example, fumed silica (gas phase silica), precipitated silica (wet silica), etc. can be cited. In addition, it is also suitable to use silica after the surface of these silicas is hydrophobized by using chlorosilane or hexamethyldisilazane, etc. Among them, fumed silica with excellent dynamic fatigue properties is preferred.

[0085] The above-mentioned (B) component may be used alone or in combination of two or more.

[0086] The amount of reinforcing silica as component (B) is 5 to 100 parts by mass, preferably 10 to 50 parts by mass, relative to 100 parts by mass of the organopolysiloxane raw rubber as component (A). If the amount of component (B) is too small, the reinforcing effect cannot be obtained, and if it is too large, the processability is deteriorated, the mechanical strength is reduced, and the dynamic fatigue durability is also deteriorated.

[0087] -(C) Ingredients-

[0088] In the present invention, it is preferred to use a partial hydrolyzate of an organoalkoxysilane represented by the following formula (1) as the component (C). The component (C) is an essential component that functions as a surface treatment agent for reacting with the hydroxyl group (hydroxysilyl group) present on the surface of the component (B) and allowing the component (B) to be quickly and uniformly dispersed in the component (A).

[0089] RSi(OR 1 )3(1)

[0090] (In formula (1), R is a monovalent hydrocarbon group having 1 to 12 carbon atoms, R 1 It represents an alkyl group having 1 to 4 carbon atoms.

[0091] Preferably, the R and R in the formula (1) are 1 Each of the following groups is independently selected from the group consisting of a methyl group, an ethyl group, and a propyl group.

[0092] Specific examples of the above-mentioned organoalkoxysilane include trimethoxy(methyl)silane, trimethoxy(ethyl)silane, trimethoxy(propyl)silane, trimethoxy(butyl)silane, trimethoxy(hexyl)silane, triethoxy(methyl)silane, tripropoxy(methyl)silane, and tributoxy(methyl)silane. Among them, trimethoxy(methyl)silane, trimethoxy(ethyl)silane, and triethoxy(methyl)silane are preferred, and trimethoxy(methyl)silane is more preferred. Partial hydrolyzates of these organoalkoxysilanes can be used as component (C). In addition, since component (C) is a partial hydrolyzate, in addition to the monovalent hydrocarbon group derived from the above R or the monovalent hydrocarbon group derived from the above OR 1 In addition to the alkoxy groups, a part of hydroxyl groups (hydroxysilyl groups) may also be present.

[0093] Here, the degree of polymerization of the partial hydrolyzate of the organic alkoxysilane of the component (C) is preferably 2 to 100, and the partial hydrolyzate with a degree of polymerization of 2 to 30 is particularly preferred as the main component. In the case where a monomer is used as the component (C) instead of a partial hydrolyzate, it is easy to volatilize and thus evaporates during kneading, and the plasticity of the resulting silicone rubber compound becomes unstable. Moreover, since the amount of volatile components increases, industrial hazards such as inhalation of volatile vapors and ignition are associated. If the degree of polymerization of the component (C) is 100 or less, the viscosity of the component (C) will not increase, so it is easy to blend, or the surface treatment of the above-mentioned component (B) can be increased. Therefore, it helps to shorten the blending time and stabilize the plasticity of the resulting silicone rubber compound.

[0094] The kinematic viscosity of the component (C) at 25°C is preferably 1.0 to 1,000 mm 2 / s, more preferably 1.5~500mm 2 / s, particularly preferably 1.5~300mm 2 / s. The kinematic viscosity is a value measured by a method using a Canon-Fenske viscometer described in JIS Z 8803: 2011. Within this range, blending with other components is easy and volatile components can be suppressed, which is preferred.

[0095] In addition, relative to 100 parts by mass of the above-mentioned component (A), the addition amount of the partial hydrolyzate of the organoalkoxysilane of component (C) is preferably in the range of 0.1 to 20 parts by mass, and preferably in the range of 0.5 to 10.0 parts by mass. When the addition amount of component (C) is less than 0.1 parts by mass, reverse plasticization occurs, resulting in poor processability thereafter, or in the worst case, it becomes impossible to obtain a composite. In addition, when the addition amount of component (C) is greater than 20 parts by mass, the resulting composite may also become sticky, resulting in poor processability thereafter, or the mechanical properties of the silicone rubber formed by curing the composite are reduced.

[0096] -(D) Component-

[0097] The component (D) is a condensation reaction catalyst for causing the hydroxysilyl groups present on the surface of the reinforcing silica of the component (B) or the hydroxysilyl groups of the component (C) to condense with each other.

[0098] As the component (D), one or more condensation reaction catalysts selected from the following (D1) to (D3) are used.

[0099] The component (D1) is an amine compound having a boiling point of 30 to 60°C at 1013 hPa and being liquid at 25°C. Specific examples of the component (D1) include lower alkylamines such as propylamine (melting point: -83°C, boiling point: 49°C), isopropylamine (melting point: -101°C, boiling point: 33°C), tert-butylamine (melting point: -72.65°C, boiling point: 46°C), and lower dialkylamines such as diethylamine (melting point: -50°C, boiling point: 56°C). The melting point and boiling point described above are the temperatures described in the SDS published by FUJIFILM Wako Pure Chemical Corporation.

[0100] Relative to 100 parts by mass of the above-mentioned (A) component, the addition amount of the above-mentioned (D1) component is 0.0001 to 0.1 parts by mass, preferably 0.001 to 0.05 parts by mass. If the amount of the (D1) component used is too small, the time required for the surface treatment of the reinforcing silica may be prolonged, or the surface treatment degree may be reduced, so that the kneaded product of the kneaded silicone rubber compound cannot be obtained. On the contrary, if the amount of the (D1) component used is too much, it may not be possible to remove the (D1) component from the kneaded product of the kneaded silicone rubber compound, and the plasticity will increase over time. In addition, when a silicone rubber cured product is to be obtained by addition curing using a platinum catalyst, the physical properties of the cured product may be unstable, or the cured product may become sticky (adhesive) on the surface due to insufficient curing.

[0101] The component (D2) is hexaorganodisilazane represented by the following general formula (2).

[0102] R 2 3SiNHSiR 2 3(2)

[0103] (In formula (2), R 2 are independently an alkyl group having 1 to 12 carbon atoms. )

[0104] In the above formula (2), R 2 The same groups as those for R in the component (A) are mentioned, and particularly preferred are alkyl groups having 1 to 6 carbon atoms such as methyl and ethyl. In addition, the molecule may have an alkenyl group such as vinyl.

[0105] Specific examples of the component (D2) include hexamethyldisilazane, 1-vinylpentamethyldisilazane, 1,3-divinyl-1,1,3,3-tetramethyldisilazane, and 1,3-dimethyl-1,1,3,3-tetravinyldisilazane. Hexamethyldisilazane and 1,3-divinyl-1,1,3,3-tetramethyldisilazane are preferred, and hexamethyldisilazane is more preferred.

[0106] Relative to 100 parts by mass of the above-mentioned (A) component, the blending amount of the (D2) component is 0.001 to 1 part by mass, preferably 0.01 to 0.50 parts by mass, and more preferably 0.01 to 0.3 parts by mass. If the amount of the (D2) component used is too small, the time required for the surface treatment of the reinforcing silica may be prolonged, or the surface treatment degree may be reduced, so that the kneaded product of the kneaded silicone rubber compound cannot be obtained. On the contrary, if the amount of the (D2) component used is too much, it may not be possible to remove the (D2) component from the kneaded product of the kneaded silicone rubber compound, and the plasticity will increase over time. In addition, when a silicone rubber cured product is obtained by addition curing using a platinum catalyst, the physical properties of the cured product may be unstable, or the cured product surface may become sticky due to insufficient curing. In addition, it is also not economically preferred.

[0107] Component (D3) is 1.0 to 30.0% by mass of aqueous ammonia. The concentration of aqueous ammonia is 1.0 to 30.0% by mass, preferably about 10.0 to 28.0% by mass, more preferably about 15.0 to 28.0% by mass.

[0108] Relative to 100 parts by mass of the above-mentioned (A) component, the blending amount of the (D3) component is 0.001 to 1 parts by mass, preferably 0.005 to 1 parts by mass, and more preferably 0.01 to 0.8 parts by mass. If the usage of the (D3) component is too little, the time required for the surface treatment of the reinforcing silica may be prolonged, or the degree of surface treatment may be reduced, so that the kneaded product of the kneaded silicone rubber compound cannot be obtained. On the contrary, if the usage of the (D3) component is too much, the (D3) component may not be removed from the kneaded product of the kneaded silicone rubber compound, and the plasticity may increase over time, or when a silicone rubber cured product is obtained by addition curing using a platinum catalyst, the physical properties of the cured product may be unstable, or the cured product surface may become sticky due to insufficient curing. In addition, it is also not economically preferred.

[0109] There is no particular restriction on the method of adding the component (D). It is preferred that the component (D) is added to the component (C) and then quickly added to the kettle to which the component (B) is added. This allows the condensation reaction of the hydroxysilyl group of the component (B) with the hydroxysilyl group of the component (C) to be effectively carried out. In addition, in order to facilitate kneading the component (D) with a double-roll mill or a kneading machine, the component (D) may be prepared as a paste with an organopolysiloxane or the like.

[0110] The kneadable silicone rubber compound of the present invention is preferably prepared using a device that can uniformly knead the above-mentioned (A) to (D) components in a specified amount. There is no particular restriction on the device that can uniformly knead. If the reactivity of the (D) component or the removal after the reaction is completed is taken into consideration, it is preferred to use a device that easily generates stirring heat. Specifically, the kneadable silicone rubber compound can be obtained by kneading using a kneader, a Banbury mixer, a roll mill, etc., among which it is particularly preferred to use a kneader for preparation.

[0111] When the above-mentioned (A) to (D) components are mixed, the partial hydrolyzate of the organoalkoxysilane as the (C) component acts as the wetting agent of the above-mentioned (B) component, i.e., the reinforcing silica. For promoting its wetting effect, it is effective to add a condensation reaction catalyst as the (D) component. At this time, water can be added as an arbitrary component according to the situation to further promote wetting. By adding this component, the partial hydrolyzate of the organoalkoxysilane as the (C) component quickly promotes the role of the wetting agent as the (B) component, i.e., the reinforcing silica. In order to effectively treat the hydroxysilyl group present on the surface of the (B) component, the (C) component must contain a reactive group that reacts quickly with the hydroxysilyl group. Based on this, a partial hydrolyzate of the organoalkoxysilane that contains more reactive groups with the hydroxysilyl group in the molecule and hardly causes three-dimensional crosslinking is effective.

[0112] Here, the preferred temperature for mixing the components (A) to (D) is in the range of 0 to 200° C., more preferably in the range of 10 to 180° C., and even more preferably in the range of 20 to 170° C. In addition, the time for mixing the components (A) to (D) is not particularly limited, but in consideration of the efficiency of the preparation, it is preferably set to a condition of preferably 1 to 300 minutes, and more preferably 10 to 120 minutes.

[0113] When the above-mentioned components (A) to (D) are mixed by the above-mentioned method, stirring heat will be generated. The amount of stirring heat generated varies depending on the degree of polymerization of the component (A) used, the amount of reinforcing silica added to the component (B), and the addition ratio of the components (A) and (B). Specifically, if a composition suitable for a kneading type silicone rubber compound is used, that is, a composition such as an existing kneading type silicone rubber compound, stirring heat of about 30 to 120°C will be generated. Here, the component (D) is excellent in handling properties because it is a liquid when mixed, and on this basis, the reactivity of the component (B) and the component (C) is excellent. In particular, in the case of the component (D1), since the boiling point at normal pressure, that is, 1013 hPa, is 30 to 60°C, the component (D) can be removed from the kneading type silicone rubber compound only by the stirring heat generated during mixing. In addition, when the component (D2) or (D3) is added, ammonia is generated due to the water and the like present in the system, which further promotes the reaction of the component (B) and the component (C). This ammonia can be removed from the kneadable silicone rubber compound simply by the stirring heat generated during blending.

[0114] Therefore, it is possible to provide the same kneadable silicone rubber compound as the existing one to the market while contributing to the recent decarbonization society and reducing environmental issues such as CO2 emissions.

[0115] In addition, since the condensation reaction catalyst of the component (D) used in the present invention hardly remains in the kneaded product obtained by kneading the kneadable silicone rubber compound, there is no problem of catalyst poisoning in the hydrosilylation reaction. Therefore, even when an addition reaction type curing agent is used, it can be suitably used.

[0116] [Mixed silicone rubber composition]

[0117] Furthermore, the kneadable silicone rubber composition of the present invention comprises a kneaded product obtained by kneading the kneadable silicone rubber compound and (E) a curing agent.

[0118] -(E) Component-

[0119] The (E) curing agent is not particularly limited as long as it is a substance that cures the above-mentioned (A) component. Generally, as the rubber curing agent, the known (E1) addition reaction (hydrosilylation reaction) type curing agent, that is, a hydrosilylation reaction curing agent composed of a combination of an organohydrogenpolysiloxane (crosslinking agent) and a hydrosilylation catalyst, or (E2) an organic peroxide is preferred.

[0120] The organohydrogenpolysiloxane as a crosslinking agent of the addition reaction type curing agent (E1) has two or more hydrosilyl groups in one molecule. In particular, the organohydrogenpolysiloxane represented by the following formula (3) is preferred.

[0121] [Chemical formula 1]

[0122]

[0123] (In formula (3), R 3 are independently a hydrogen atom, or a group selected from an alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms, and two or more R in one molecule 3 is a hydrogen atom. In addition, there will not be more than two hydrogen atoms on the same silicon atom. a is an integer of 2≤a≤30, b is an integer of 0≤b≤300, c is an integer of 0≤c≤10, and d is an integer of 0≤d≤30. In addition, the combination of each siloxane unit can be block or random.)

[0124] Here, R 3 are independently a hydrogen atom, or a group selected from an alkyl group having 1 to 8 carbon atoms, preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 10 carbon atoms, preferably an aryl group having 6 to 8 carbon atoms, and an aralkyl group having 7 to 10 carbon atoms, preferably an aralkyl group having 7 to 9 carbon atoms. 3 is a hydrogen atom, preferably 2 to 200 R 3 is a hydrogen atom, more preferably 2 to 130 R 3 is a hydrogen atom. In addition, there will not be more than two hydrogen atoms on the same silicon atom. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl and other alkyl groups, and cycloalkyl groups such as cyclohexyl. Examples of aryl groups include phenyl, tolyl and the like. Examples of aralkyl groups include benzyl, 2-phenylpropyl and the like. In addition, fluoroalkyl groups in which a part of the alkyl group is substituted with a fluorine atom may also be used. In addition, a is an integer of 2≤a≤30, preferably an integer of 2≤a≤20. b is an integer of 0≤b≤300, preferably an integer of 3≤b≤200. c is an integer of 0≤c≤10, preferably an integer of 0≤c≤5. And d is an integer of 0≤d≤30, preferably an integer of 0≤d≤20.

[0125] In addition, the molecular structure of the organohydrogenpolysiloxane may be any of a linear, cyclic, branched, and three-dimensional network structure. In this case, an organohydrogenpolysiloxane having a silicon atom number (or polymerization degree) of about 2 to 300, particularly about 4 to 200, in a molecule and being liquid at 25° C. is preferably used. In addition, the hydrosilyl group may be at the end of the molecular chain, at the side chain (in the middle of the molecular chain), or at both locations.

[0126] Examples of the organohydrogenpolysiloxane include 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogencyclopolysiloxane, methylhydrogensiloxane-dimethylsiloxane cyclic copolymer, tris(dimethylhydrogensiloxane)methylsilane, tris(dimethylhydrogensiloxane)phenylsilane, methylhydrogenpolysiloxane terminated at both ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer terminated at both ends with trimethylsiloxy groups, and dimethylhydrogensiloxane-methylhydrogensiloxane copolymer terminated at both ends with dimethylhydrogensiloxy groups. End-capped dimethyl polysiloxane, dimethyl hydrogen siloxane-methyl hydrogen siloxane copolymer end-capped at both ends with dimethyl hydrogen siloxane alkoxy groups, methyl hydrogen siloxane-diphenyl siloxane copolymer end-capped at both ends with trimethyl hydrogen siloxane alkoxy groups, methyl hydrogen siloxane-diphenyl siloxane-dimethyl siloxane copolymer end-capped at both ends with trimethyl hydrogen siloxane alkoxy groups, cyclic methyl hydrogen polysiloxane, cyclic methyl hydrogen siloxane-dimethyl siloxane copolymer, cyclic methyl hydrogen siloxane-diphenyl siloxane-dimethyl siloxane copolymer, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 The copolymer is composed of (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 Unit and (C6H5)SiO 3 / 2 or in the above-mentioned exemplified compounds, some or all of the methyl groups are replaced by other alkyl groups such as ethyl and propyl groups or aryl groups such as phenyl groups, etc. In addition, as such an organohydrogenpolysiloxane, specifically, the compound of the following structural formula can be exemplified.

[0127] [Chemical formula 2]

[0128]

[0129] (In the formula, k is an integer from 2 to 10, and s and t are integers from 0 to 10 respectively.)

[0130] The organohydrogenpolysiloxane preferably has a viscosity of 0.5 to 10,000 mPa·s, particularly preferably 1 to 300 mPa·s at 25° C. The viscosity is a value measured by a rotational viscometer according to the method described in JIS K7117-1:1999.

[0131] Furthermore, the organohydrogenpolysiloxane is preferably blended in an amount such that the molar ratio of hydrogen atoms bonded to silicon atoms (i.e., hydrosilyl groups) in the organohydrogenpolysiloxane to alkenyl groups bonded to silicon atoms in the component (A) (hydrosilyl groups / alkenyl groups) is 0.5 to 10, preferably 0.8 to 6, and more preferably 1 to 5. If the molar ratio is 0.5 or more, crosslinking is sufficient and sufficient mechanical strength can be obtained, and if the molar ratio is 10 or less, physical properties after curing are not reduced, and in particular, heat resistance and compression set resistance are not deteriorated.

[0132] In addition, the hydrosilylation catalyst used for the above-mentioned (E1) addition reaction type curing agent is a catalyst that promotes the addition reaction of the alkenyl group in the above-mentioned (A) component with the hydrosilyl group in the above-mentioned organohydrogen polysiloxane as a crosslinking agent. As the hydrosilylation catalyst, platinum group metal catalysts such as ruthenium or platinum can be listed. Among the platinum group metal catalysts, there are metal monomers and compounds of these platinum groups. Among them, catalysts that have been known as catalysts for addition reaction curing type silicone rubber compositions can be used. For example, microparticles of platinum metal adsorbed on carriers such as silica, alumina or silica gel, platinum chloride, chloroplatinic acid, reactants of chloroplatinic acid and monohydric alcohols, complexes of chloroplatinic acid and olefins, complexes of chloroplatinic acid and vinyl-containing (poly)siloxanes, complexes of chloroplatinic acid and phosphites, and complexes of these compounds with vinyl-containing (poly)siloxanes, etc., palladium catalysts, rhodium catalysts, ruthenium catalysts, etc. Among them, platinum or platinum compounds are particularly preferred.

[0133] The amount of the hydrosilylation catalyst added is the so-called catalytic amount that can promote the addition reaction. Generally, it can be used in the range of 1 ppm to 1 mass % relative to the amount of the above-mentioned (A) component calculated as the mass of the platinum group metal, preferably in the range of 10 to 500 ppm. As long as the addition amount is 1 ppm or more, the addition reaction can be fully promoted and the curing is sufficient. On the other hand, as long as it is 1 mass % or less, the cost can be saved.

[0134] In addition to the above-mentioned catalysts, an addition crosslinking control agent may be used for the purpose of adjusting the curing rate. Specifically, ethynylcyclohexanol or tetramethyltetravinylcyclotetrasiloxane may be mentioned.

[0135] On the other hand, examples of the organic peroxide (E2) include benzoyl peroxide, 2,4-dichlorobenzoyl peroxide, p-methylbenzoyl peroxide, o-methylbenzoyl peroxide, 2,4-diisopropylbenzene peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, di-tert-butyl peroxide, tert-butyl peroxybenzoate, and 1,6-hexanediol-bis-tert-butylperoxy carbonate.

[0136] The amount of organic peroxide added is preferably 0.1 to 15 parts by mass, particularly preferably 0.2 to 10 parts by mass, relative to 100 parts by mass of component (A). As long as the amount added is 0.1 parts by mass or more, the crosslinking reaction is fully carried out, and no deterioration of physical properties such as reduced hardness or insufficient rubber strength or increased compression set will occur. In addition, as long as the amount added is 15 parts by mass or less, it is economically preferred, and the decomposition products of the curing agent are sufficiently small, and no deterioration of physical properties such as increased compression set or increased discoloration of the obtained sheet will be increased.

[0137] In addition to the above-mentioned components, the kneadable silicone rubber composition of the present invention may also be added with conductivity imparting agents such as carbon black, flame retardants such as iron oxide or halogenated compounds, antistatic agents, softeners, anti-aging agents, ultraviolet absorbers, colorants, etc. according to the purpose of the present invention.

[0138] The kneadable silicone rubber composition of the present invention obtained as described above can be cured at 60 to 300° C., particularly at 80 to 200° C., for 5 seconds to 1 hour, particularly for 30 seconds to 30 minutes to obtain a cured silicone rubber.

[0139] [Method for preparing kneading type silicone rubber composition]

[0140] The kneadable silicone rubber composition of the present invention can be obtained by kneading the kneadable silicone rubber compound described above, performing surface treatment of the component (B) with the component (C) in the presence of the component (D) as a catalyst, and simultaneously removing the component (D) by stirring heat and then adding the curing agent (E).

[0141] In this case, it is preferred to use, as the component (E), a curing agent for a hydrosilylation reaction consisting of a combination of an organohydrogenpolysiloxane and a hydrosilylation catalyst, or an organic peroxide.

[0142] Example

[0143] The present invention is specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, the melting point and boiling point are values ​​at 1013 hPa, the average degree of polymerization is a value measured as a weight average degree of polymerization based on polystyrene conversion by gel permeation chromatography (GPC) analysis, the viscosity is a value measured by a rotational viscometer using the method described in JIS K 7117-1: 1999, the kinematic viscosity is a value measured by a Canon-Fenske viscometer using the method described in JIS Z 8803: 2011, and the refractive index is a value measured by an Abbe refractometer using the method described in JIS K 0062: 1992.

[0144] Specific examples of the components used in the examples and comparative examples of the present invention are shown below.

[0145] (A) Organic polysiloxane rubber

[0146] An organic polysiloxane rubber composed of 99.825 mol% of dimethylsiloxane units, 0.15 mol% of methylvinylsiloxane units, and 0.025 mol% of dimethylvinylsiloxane units, having an average of 12 vinyl groups bonded to silicon atoms in one molecule and an average degree of polymerization of 6,000

[0147] (B) Strengthening Silica

[0148] (B-1) The specific surface area based on the BET adsorption method is 200 m 2 / g of fumed silica (product name: AEROSIL200, manufactured by NIPPON AEROSIL CO., LTD.)

[0149] (B-2) The specific surface area based on the BET adsorption method is 130 m 2 / g surface treated silica (product name: AEROSIL R-972, manufactured by NIPPON AEROSIL CO., LTD.)

[0150] (C) Partial hydrolyzate of organoalkoxysilane

[0151] (C-1) Partial hydrolyzate of trimethoxy(methyl)silane (product name: KC-89S, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity [25° C.]: 5 mm 2 / s, refractive index [25°C]: 1.394)

[0152] (C-2) Partial hydrolyzate of trimethoxy(methyl)silane (product name: X-40-9225, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity [25° C.]: 100 mm 2 / s, refractive index [25°C]: 1.407)

[0153] (C-3) Trimethoxy(methyl)silane (product name: KBM-13, manufactured by Shin-Etsu Chemical Co., Ltd., kinematic viscosity [25° C.]: 0.5 mm 2 / s) [for comparative example]

[0154] (C-4) Linear partial hydrolyzate of tetramethoxysilane (product name: methyl silicate oligomer MKC Silicate MS-51, manufactured by Mitsubishi Chemical Corporation, kinematic viscosity [25°C]: 7 mm 2 / s) [for comparative example]

[0155] (D) Catalyst for condensation reaction

[0156] (D1) Amine compounds that are liquid at 25°C (low boiling point amine compounds)

[0157] Isopropylamine (melting point: -101°C, boiling point: 33°C)

[0158] (D2) Hexaorganodisilazane

[0159] Hexamethyldisilazane (product name: SZ-31, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0160] (D3) Ammonia

[0161] 28% ammonia water

[0162] The above-mentioned components were blended in the amounts shown in Table 1, and a kneaded product of a kneadable silicone rubber compound was obtained through the following steps.

[0163] [Process for preparing kneaded product of kneadable silicone rubber compound]

[0164] In a kneader having a volume of 3 L, components (C) and (D) were added in the amounts described in Table 1 to 100 parts by mass of component (A) and 40 parts by mass of component (B), and kneaded uniformly, and then kneaded for 2 hours at the temperature described in Table 1, thereby obtaining a kneaded product of a kneadable silicone rubber compound. In Table 1, "heat treatment mixing" refers to a method of heating from the outside to a set temperature and mixing for a predetermined time on this basis, and "simple mixing" refers to mixing for a predetermined time only by a temperature rise from room temperature based on stirring heat without heating from the outside.

[0165] ○Plasticity determination

[0166] The kneaded products of the kneaded silicone rubber compounds prepared in Examples 1 to 6 and Comparative Examples 1 to 2 were kneaded 15 times using three rolls, and the Williams plasticity was measured by the method described in JIS K6249: 2003 after 10 minutes (initial period), and then the plasticity after 1 day at 40°C was measured, and the change in plasticity after 1 day at 40°C relative to the initial period was calculated to evaluate the change over time. The case where the value of the change over time is within ±50 is judged as qualified (equal to or better than the existing product), and the case where it deviates from this value is judged as unqualified (inferior to the existing product).

[0167] ○Physical property measurement

[0168] 0.01 parts by mass of a platinum catalyst containing 1% by mass of a chloroplatinic acid-divinyldisiloxane complex in terms of platinum atomic mass (manufactured by Shin-Etsu Chemical Co., Ltd.) and 0.85 parts by mass of an organohydrogenpolysiloxane represented by the following formula (manufactured by Shin-Etsu Chemical Co., Ltd.) were added as (E1) an addition reaction type curing agent to 100 parts by mass of the kneaded products of the kneaded silicone rubber compounds prepared in Examples 1 to 6 and Comparative Examples 1 to 2, and the kneaded products were uniformly mixed to prepare a kneaded silicone rubber composition, which was then press-cured at 120° C. for 10 minutes and then post-cured at 200° C. for 4 hours to prepare a test piece. The hardness (durometer A), tensile strength, elongation at break, and compression set (150° C. / 22 hours, 25% compression) of the prepared test piece were measured based on the description of JIS K 6249:2003. Furthermore, rebound resilience was measured by the method described in JIS K 6255: 2013. Products with a breaking elongation of 500% or less or a compression set of more than 30% were judged as unacceptable due to poor physical properties.

[0169] [Chemical formula 3]

[0170]

[0171] [Table 1]

[0172]

[0173] [Evaluation results]

[0174] It can be seen that the kneaded silicone rubber compounds obtained in Examples 1 to 6 satisfy the requirements of the present invention. As a result, the physical property values ​​of the kneaded products of the kneaded silicone rubber compounds and the physical property values ​​of the molded test pieces of the kneaded silicone rubber compositions prepared using the kneaded products satisfy the target performance values.

[0175] However, for Comparative Example 1, although the structure of the organic alkoxysilane as component (C) is the same, it is not a partial hydrolyzate. As a result, the organic alkoxysilane mixed in the kneading or heat treatment mixing volatilizes, so the surface treatment degree of the reinforcing silica as component (B) is reduced. As a result, the initial plasticity becomes higher, and the plasticity after 40°C × 24 hours also becomes larger. Moreover, it can be seen that for the physical properties of the molding test piece of the kneaded silicone rubber composition made using the kneaded product of the kneaded silicone rubber compound of Comparative Example 1, the elongation at break and the compression set have deteriorated compared with Examples 1 to 6. In summary, the results deviate from the target values.

[0176] In addition, in Comparative Example 2, a partial hydrolyzate of an organic alkoxysilane with a different structure was used as the (C) component. Since the partial hydrolyzate has a high ability to perform three-dimensional crosslinking, the initial plasticity of the obtained kneaded product of the kneaded silicone rubber compound is very high, and it can be confirmed that the plasticity has further increased after 40°C × 24 hours. The kneading uniformity of the kneaded product of the kneaded silicone rubber compound with such a very high initial plasticity is also reduced. Therefore, it can be seen that the physical properties of the molding test pieces of the kneaded silicone rubber composition made using the kneaded products of these kneaded silicone rubber compounds are worse than those of Examples 1 to 6 in terms of elongation at break and compression set.

[0177] The above results show that the kneadable silicone rubber compound of the present invention can obtain a very stable kneaded product of the kneadable silicone rubber compound regardless of the kneading conditions, and the kneadable silicone rubber composition prepared using the kneaded product also has very good physical properties.

[0178] Industrial Applicability

[0179] The kneadable silicone rubber compound of the present invention and the kneadable silicone rubber composition obtained by mixing a curing agent into the kneaded product of the compound can provide a kneadable silicone rubber compound and a kneadable silicone rubber composition that can have a higher plasticity even in a kneadable silicone rubber compound of relatively low hardness. Therefore, it is particularly possible to contribute to the dimensional stability of low-hardness extrusion molding materials, etc. In addition, the kneadable silicone rubber composition using the kneaded product of the kneadable silicone rubber compound is expected to be widely used in electrical appliances, automobiles, construction, medical care, food fields, etc.

[0180] The present invention is not limited to the above-mentioned embodiments. The above-mentioned embodiments are illustrative only, and any technical solution having substantially the same structure and achieving the same technical effect as the technical concept described in the claims of the present invention is included in the protection scope of the present invention.

Claims

1. A kneadable silicone rubber compound, characterized in that: It contains: 100 parts by mass of (A) an organopolysiloxane raw rubber having two or more alkenyl groups bonded to silicon atoms in one molecule and an average degree of polymerization of 1,000 to 100,000; 5 to 100 parts by mass of (B) reinforcing silica, the specific surface area of ​​which based on the BET adsorption method is 50 to 450 m 2 / g; 0.1 to 20 parts by mass of (C) a partial hydrolyzate of an organoalkoxysilane represented by the following general formula (1), RSi(OR 1 )3(1) In formula (1), R is a monovalent hydrocarbon group having 1 to 12 carbon atoms, 1 represents an alkyl group having 1 to 4 carbon atoms; and (D) one or more condensation reaction catalysts selected from the group consisting of (D1) to (D3): 0.0001 to 0.1 parts by mass of (D1) an amine compound having a boiling point of 30 to 60° C. at 1013 hPa and being liquid at 25° C.; 0.001 to 1 parts by mass of (D2) hexaorganodisilazane represented by the following general formula (2), <h2 style=";text-align:left;direction:ltr">R<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> 3SiNHSiR<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> 3(2) In formula (2), R 2 are independently an alkyl group having 1 to 12 carbon atoms; 0.001 to 1 parts by mass of (D3) 1.0 to 30.0% by mass of aqueous ammonia.

2. The millable silicone rubber compound according to claim 1, characterized in that: The R and R of the formula (1) 1 Each of the following groups is independently selected from the group consisting of a methyl group, an ethyl group, and a propyl group.

3. A kneadable silicone rubber composition, characterized in that: The invention comprises a kneaded product obtained by kneading the kneadable silicone rubber compound according to claim 1 or claim 2 and (E) a curing agent.

4. The millable silicone rubber composition according to claim 3, characterized in that: The component (E) is a curing agent for a hydrosilylation reaction composed of a combination of an organohydrogenpolysiloxane and a hydrosilylation catalyst.

5. The millable silicone rubber composition according to claim 3, characterized in that: The component (E) is an organic peroxide.

6. A method for preparing a kneadable silicone rubber composition, characterized in that: The kneadable silicone rubber compound according to claim 1 or claim 2 is kneaded, and the surface of the component (B) is treated with the component (C) in the presence of the component (D) as a catalyst, and the component (D) is removed by stirring heat, and then the curing agent (E) is added.

7. The method for preparing the millable silicone rubber composition according to claim 6, characterized in that: As the component (E), a curing agent for a hydrosilylation reaction consisting of a combination of an organohydrogenpolysiloxane and a hydrosilylation catalyst, or an organic peroxide is used.

Images