Crosslinkable cyanated silicone composition and crosslinked cyanated silicone elastomer produced therefrom

Abstract

To provide a crosslinkable silicone composition that enables formation of a silicone elastomer exhibiting a high dielectric constant and excellent elongation at break.SOLUTION: A crosslinkable cyanated silicone composition comprises a linear cyanated silicone polymer (A) having a weight-average molecular weight of 1000 or more and containing structural units having a vinyl group and structural units having a cyano group in a side chain, and a linear cyanated silicone polymer (B) having a weight-average molecular weight of 2000 or more and containing structural units having a hydrosilyl group and structural units having a cyano group in a side chain, wherein it is preferable that the cyanated silicone polymer (A) has structural units containing a vinyl group at least at a terminal.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a crosslinkable cyanated silicone composition and a crosslinked cyanated silicone elastomer using the same. [Background technology]

[0002] Silicone polymers are polymeric materials with properties such as low elastic modulus, high electrical resistance, and high moisture resistance, making them useful as materials for forming dielectric layers in actuators and sensors. However, conventional silicone polymers do not necessarily have a sufficiently high dielectric constant. Therefore, Japanese Patent Laid-Open Publication No. 2002-265788 (Patent Document 1) discloses a highly dielectric addition-type curable composition, which contains (a) an organopolysiloxane containing a cyanoalkyl group and a monovalent hydrocarbon group having an aliphatic unsaturated bond, (b) a cyanoalkyl group-containing organohydrogenpolysiloxane, and (c) a platinum group metal catalyst. Because the cyanoalkyl group-containing organohydrogenpolysiloxane (b) contained in this curable composition has a branched structure, it is prone to gelation during preparation and molding, such as film formation, making it difficult to form a uniform dielectric layer.

[0003] Furthermore, Japanese Patent Laid-Open Publication No. 2013-28724 (Patent Document 2) discloses a curable composition having hydrosilylation reactivity, which comprises a compound (A) having an alkenyl group and a polysiloxane compound (B) having a hydrosilyl group and a cyano group and an alkenyl group in a side chain, and also describes that a thin film formed from this curable composition has a high dielectric constant. However, the polysiloxane compound (B) contained in this curable composition has a terminal trimethylsilyl group, and therefore the number of crosslinking groups is small, and the silicone elastomer obtained by curing this curable composition has a low crosslink density and is not necessarily sufficient in mechanical properties. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-265788 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-28724 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention was made in consideration of the problems associated with the prior art described above, and has as its object to provide a silicone elastomer that has a high relative dielectric constant and excellent elongation at break, and a crosslinkable silicone composition that can form this silicone elastomer. [Means for solving the problem]

[0006] As a result of extensive research conducted by the inventors in order to achieve the above-mentioned object, they discovered that by using a crosslinkable cyanated silicone composition containing a high molecular weight linear cyanated silicone polymer having vinyl groups and a high molecular weight linear cyanated silicone polymer having hydrosilyl groups, it is possible to obtain a crosslinked cyanated silicone elastomer with a high dielectric constant and excellent elongation at break, which led to the completion of the present invention.

[0007] That is, the present invention provides the following aspects. [1] A linear cyanated silicone polymer (A) having a weight average molecular weight of 1000 or more and having a structural unit containing a vinyl group and a structural unit containing a cyano group in a side chain; a linear cyanated silicone polymer (B) having a weight average molecular weight of 2000 or more and having a structural unit containing a hydrosilyl group and a structural unit containing a cyano group in the side chain; A crosslinkable cyanated silicone composition comprising: [2] The crosslinkable cyanated silicone composition according to [1], wherein the cyanated silicone polymer (A) has structural units containing vinyl groups at least at the terminals. [3] The crosslinkable cyanated silicone composition according to [1] or [2], wherein the cyanated silicone polymer (B) has a structural unit containing a hydrosilyl group at least at the terminal. [4] The crosslinkable cyanated silicone composition according to any one of [1] to [3], wherein the weight-average molecular weight of the cyanated silicone polymer (A) is 3,000 or more. [5] The crosslinkable cyanated silicone composition according to any one of [1] to [4], wherein the weight-average molecular weight of the cyanated silicone polymer (B) is 5,000 or more. [6] The cyanated silicone polymer (A) is represented by the following formula (a):

[0008] [ka]

[0009] [In the above formula, Z represents either a divalent hydrocarbon group or a divalent hetero group, each of the multiple Rs independently represents a monovalent hydrocarbon group, a is 0.45 to 0.98, b is 0 to 0.50, c is 0 to 0.15, d is 0.01 to 0.20, and a+b+c+d=1] It is expressed as The cyanated silicone polymer (B) is represented by the following formula (b):

[0010] [ka]

[0011] [In the above formula, Z represents either a divalent hydrocarbon group or a divalent hetero group, each of the multiple Rs independently represents a monovalent hydrocarbon group, e is 0.45 to 0.98, f is 0 to 0.45, g is 0 to 0.10, h is 0.01 to 0.15, and e+f+g+h=1] The crosslinkable cyanated silicone composition according to any one of [1] to [5], which is represented by the following formula: [7] A hydrosilylation reaction product of the crosslinkable cyanated silicone composition according to any one of [1] to [6], A crosslinked cyanated silicone elastomer in which a vinyl group of the cyanated silicone polymer (A) and a hydrosilyl group of the cyanated silicone polymer (B) form a covalent bond. [8] The crosslinked cyanated silicone elastomer according to [7], wherein the hydrosilylation reaction product is a crosslinked product obtained by a platinum group catalyst.

[0012] Although the reason why the crosslinkable cyanated silicone composition of the present invention produces a silicone elastomer with a high dielectric constant is not entirely clear, the inventors speculate as follows. Specifically, the crosslinkable cyanated silicone composition of the present invention contains (A) a high-molecular-weight linear cyanated silicone polymer having vinyl groups and (B) a high-molecular-weight linear cyanated silicone polymer having hydrosilyl groups. When this crosslinkable cyanated silicone composition is crosslinked, a crosslinked silicone elastomer with cyano groups in its side chains is formed. Because cyano groups are highly polarizable functional groups, it is speculated that the crosslinked silicone elastomer of the present invention has a high dielectric constant.

[0013] In the crosslinked cyanated silicone elastomer of the present invention, the vinyl groups of the cyanated silicone polymer (A) and the hydrosilyl groups of the cyanated silicone polymer (B) are bonded to each other in a manner satisfying the following formula:

[0014] [ka]

[0015] (In the formula, Z and R have the same meanings as Z and R in the formulas (a) and (b).) As shown in the figure, a covalent bond is formed by a hydrosilylation reaction to form an alkyl silicone structure (crosslinked structure). Because this alkyl silicone structure is unlikely to impair electrical properties, it is presumed that the crosslinked cyanated silicone elastomer of the present invention, which is crosslinked by a hydrosilylation reaction, maintains a high relative dielectric constant due to the cyano groups.

[0016] Furthermore, while the reason why the crosslinkable cyanated silicone composition of the present invention produces a silicone elastomer with excellent elongation at break is not entirely clear, the inventors speculate as follows: That is, the crosslinked cyanated silicone elastomer of the present invention is formed by subjecting the crosslinkable cyanated silicone composition of the present invention to hydrosilylation, as described above. The structure (crosslinked structure) in which the vinyl groups of the cyanated silicone polymer (A) and the hydrosilyl groups of the cyanated silicone polymer (B) are covalently bonded by hydrosilylation is a structure in which the silicon atoms of the siloxane structure are crosslinked with ethylene groups, and therefore the crosslinked cyanated silicone elastomer formed is presumed to have appropriate flexibility and good elongation at break. Furthermore, in the crosslinkable cyanated silicone composition of the present invention, the cyanated silicone polymer (A) and the cyanated silicone polymer (B) both have high molecular weights, and therefore the crosslinking points are appropriately dispersed and not too densely packed, and it is presumed that the crosslinked cyanated silicone elastomer formed has high flexibility and improved elongation at break. [Effects of the Invention]

[0017] According to the present invention, it is possible to obtain a silicone elastomer having a high relative dielectric constant and excellent elongation at break. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a graph showing the molecular weight distribution of the vinyl group-containing linear cyanated silicone polymers obtained in Synthesis Example A1 and Comparative Synthesis Example A1. [Figure 2] 1 is a graph showing the molecular weight distribution of the vinyl group-containing linear cyanated silicone polymers obtained in Synthesis Examples A2 to A5. [Figure 3] 1 is a graph showing the molecular weight distribution of the vinyl group-containing linear dimethyl silicone polymer obtained in Comparative Synthesis Example A2. [Figure 4]1 is a graph showing the molecular weight distribution of the linear cyanated silicone polymers having hydrosilyl groups obtained in Synthesis Example B1 and Comparative Synthesis Example B1. [Figure 5] 1 is a graph showing the molecular weight distribution of the linear cyanated silicone polymers having hydrosilyl groups obtained in Synthesis Examples B2 to B5. [Figure 6] 1 is a graph showing the molecular weight distribution of the linear dimethylsilicone polymer having hydrosilyl groups obtained in Comparative Synthesis Example B3. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described in detail below based on preferred embodiments thereof.

[0020] [Crosslinkable Cyanated Silicone Composition] First, the crosslinkable cyanated silicone composition of the present invention will be described. The crosslinkable cyanated silicone composition of the present invention contains a linear cyanated silicone polymer (A) having a weight average molecular weight of 1000 or more and containing structural units containing vinyl groups and structural units containing cyano groups in the side chain, and a linear cyanated silicone polymer (B) having a weight average molecular weight of 2000 or more and containing structural units containing hydrosilyl groups and structural units containing cyano groups in the side chain.

[0021] (A) A high molecular weight linear cyanated silicone polymer having vinyl groups The high molecular weight linear cyanated silicone polymer (A) having a vinyl group used in the present invention is a linear silicone polymer having a weight average molecular weight of 1,000 or more and containing a structural unit containing a cyano group and a structural unit containing a vinyl group.

[0022] The cyano group-containing structural unit is a bifunctional siloxane unit having a cyano group in a side chain. The cyano group may be directly bonded to a silicon atom in the siloxane unit, but is preferably bonded via a divalent hydrocarbon group or a divalent hetero group. Examples of the divalent hydrocarbon group include an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms, with an alkylene group having 1 to 5 carbon atoms being preferred, and an alkylene group having 1 to 3 carbon atoms being more preferred. Examples of the divalent hetero group include an alkyleneoxy group having 1 to 20 carbon atoms or an aryleneoxy group having 6 to 10 carbon atoms, with an alkyleneoxy group having 1 to 10 carbon atoms being preferred, an alkyleneoxy group having 1 to 5 carbon atoms being more preferred, and an alkyleneoxy group having 1 to 3 carbon atoms being even more preferred. The remaining organic substituents bonded to silicon atoms in the siloxane units include monovalent hydrocarbon groups, preferably alkyl groups having 1 to 5 carbon atoms, and more preferably alkyl groups having 1 to 3 carbon atoms. The proportion of such cyano group-containing structural units relative to all structural units of the cyanated silicone polymer (A) is preferably 45 to 98 mol%, more preferably 50 to 90 mol%, and even more preferably 60 to 80 mol%.

[0023] The vinyl group-containing structural unit is a monofunctional or difunctional siloxane unit having a vinyl group in a side chain. The vinyl group may be bonded to a silicon atom in the siloxane unit via a divalent hydrocarbon group or a divalent hetero group, but from the viewpoint of mechanical properties, it is preferably bonded directly. Examples of the divalent hydrocarbon group include an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms, with an alkylene group having 1 to 5 carbon atoms being preferred, and an alkylene group having 1 to 3 carbon atoms being more preferred. Examples of the divalent hetero group include an alkyleneoxy group having 1 to 20 carbon atoms or an aryleneoxy group having 6 to 10 carbon atoms, with an alkyleneoxy group having 1 to 10 carbon atoms being preferred, an alkyleneoxy group having 1 to 5 carbon atoms being more preferred, and an alkyleneoxy group having 1 to 3 carbon atoms being even more preferred. The remaining organic substituents bonded to silicon atoms in the siloxane units include monovalent hydrocarbon groups, preferably alkyl groups having 1 to 5 carbon atoms, and more preferably alkyl groups having 1 to 3 carbon atoms. The vinyl-containing structural units may be present either within the main chain of the cyanated silicone polymer (A) or at the terminals, but are preferably present at least at the terminals. The proportion of such vinyl-containing structural units present within the main chain of the cyanated silicone polymer (A) is preferably 0 to 15 mol %, more preferably 5 to 10 mol %, relative to the total structural units of the cyanated silicone polymer (A), and the proportion of those present at the terminals is preferably 1 to 20 mol %, more preferably 10 to 20 mol %, and even more preferably 15 to 20 mol %.

[0024] Furthermore, the cyanated silicone polymer (A) may contain other bifunctional siloxane units in addition to the cyano group-containing structural units and the vinyl group-containing structural units. Examples of such other bifunctional siloxane units include siloxane units in which two monovalent hydrocarbon groups are bonded to one silicon atom. The monovalent hydrocarbon groups are preferably each independently an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. Examples of such other bifunctional siloxane units include dialkylsiloxane units such as dimethylsiloxane units and ethylmethylsiloxane units. The proportion of such other bifunctional siloxane units is preferably 0 to 50 mol %, more preferably 0 to 25 mol %, and even more preferably 0 to 10 mol %, based on the total structural units of the cyanated silicone polymer (A).

[0025] Examples of such cyanated silicone polymers (A) include those represented by the following formula (a):

[0026] [ka]

[0027] Examples include those represented by the following formula:

[0028] In the above formula, Z represents a divalent hydrocarbon group or a divalent hetero group. Examples of the divalent hydrocarbon group include an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms, with an alkylene group having 1 to 5 carbon atoms being preferred, and an alkylene group having 1 to 3 carbon atoms being more preferred. Examples of the divalent hetero group include an alkyleneoxy group having 1 to 20 carbon atoms or an aryleneoxy group having 6 to 10 carbon atoms, with an alkyleneoxy group having 1 to 10 carbon atoms being preferred, an alkyleneoxy group having 1 to 5 carbon atoms being more preferred, and an alkyleneoxy group having 1 to 3 carbon atoms being even more preferred.

[0029] In the formula, each of the multiple R's independently represents a monovalent hydrocarbon group. The monovalent hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms.

[0030] In the formula, a is 0.45 to 0.98, preferably 0.50 to 0.90, and more preferably 0.60 to 0.80. b is 0 to 0.50, preferably 0 to 0.25, and more preferably 0 to 0.10. c is 0 to 0.15, and preferably 0.05 to 0.10. d is 0.01 to 0.20, preferably 0.10 to 0.20, and more preferably 0.15 to 0.20. In the formula (a), a+b+c+d=1.

[0031] The weight-average molecular weight of the cyanated silicone polymer (A) must be 1,000 or greater. If the weight-average molecular weight of the cyanated silicone polymer (A) is less than the lower limit, the elongation at break of the resulting crosslinked cyanated silicone elastomer will be reduced. Furthermore, it may be difficult to easily form the crosslinked cyanated silicone elastomer into a thin film. From the viewpoints of improving the elongation at break of the resulting crosslinked cyanated silicone elastomer and facilitating the formation of a thin film of the crosslinked cyanated silicone elastomer, the weight-average molecular weight of the cyanated silicone polymer (A) is preferably 3,000 or greater. There is no particular upper limit to the weight-average molecular weight of the cyanated silicone polymer (A), but since a larger molecular weight of the polymer tends to increase viscosity and make handling difficult, a weight-average molecular weight of 100,000 or less is preferred, and 50,000 or less is more preferred.

[0032] Such a cyanated silicone polymer (A) can be prepared by reacting silane monomers corresponding to each structural unit by a known method.

[0033] (B) A high molecular weight linear cyanated silicone polymer having hydrosilyl groups The high molecular weight linear cyanated silicone polymer (B) having hydrosilyl groups used in the present invention is a linear silicone polymer having a weight average molecular weight of 2000 or more and containing structural units containing cyano groups and structural units containing hydrosilyl groups.

[0034] The cyano group-containing structural unit is a bifunctional siloxane unit having a cyano group in a side chain. The cyano group may be directly bonded to a silicon atom in the siloxane unit, but is preferably bonded via a divalent hydrocarbon group or a divalent hetero group. Examples of the divalent hydrocarbon group include an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms, with an alkylene group having 1 to 5 carbon atoms being preferred, and an alkylene group having 1 to 3 carbon atoms being more preferred. Examples of the divalent hetero group include an alkyleneoxy group having 1 to 20 carbon atoms or an aryleneoxy group having 6 to 10 carbon atoms, with an alkyleneoxy group having 1 to 10 carbon atoms being preferred, an alkyleneoxy group having 1 to 5 carbon atoms being more preferred, and an alkyleneoxy group having 1 to 3 carbon atoms being even more preferred. The remaining organic substituents bonded to silicon atoms in the siloxane units include monovalent hydrocarbon groups, preferably alkyl groups having 1 to 5 carbon atoms, and more preferably alkyl groups having 1 to 3 carbon atoms. The proportion of such cyano group-containing structural units relative to all structural units of the cyanated silicone polymer (B) is preferably 45 to 98 mol%, more preferably 50 to 95 mol%, and even more preferably 70 to 90 mol%.

[0035] The hydrosilyl group-containing structural unit has a structure (hydrosilyl group) in which a hydrogen atom is bonded to a silicon atom in a monofunctional or difunctional siloxane unit. The remaining organic substituents bonded to the silicon atom in the siloxane unit include monovalent hydrocarbon groups, preferably alkyl groups having 1 to 5 carbon atoms, and more preferably alkyl groups having 1 to 3 carbon atoms. The hydrosilyl group-containing structural unit may be present either within the main chain of the cyanated silicone polymer (B) or at the terminal, but is preferably present at least at the terminal. The proportion of such hydrosilyl group-containing structural units present within the main chain of the cyanated silicone polymer (B) is preferably 0 to 10 mol %, more preferably 1 to 5 mol %, relative to the total proportion of all structural units of the cyanated silicone polymer (B), and the proportion of those present at the terminal is preferably 1 to 15 mol %, more preferably 5 to 10 mol %.

[0036] Furthermore, the cyanated silicone polymer (B) may contain other bifunctional siloxane units in addition to the cyano group-containing structural units and the hydrosilyl group-containing structural units. Examples of such other bifunctional siloxane units include siloxane units in which two monovalent hydrocarbon groups are bonded to one silicon atom. The monovalent hydrocarbon groups are preferably each independently an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms. Examples of such other bifunctional siloxane units include dialkylsiloxane units such as dimethylsiloxane units and ethylmethylsiloxane units. The proportion of such other bifunctional siloxane units is preferably 0 to 45 mol %, more preferably 0 to 20 mol %, and even more preferably 0 to 10 mol %, based on the total structural units of the cyanated silicone polymer (B).

[0037] Examples of such cyanated silicone polymers (B) include those represented by the following formula (b):

[0038] [ka]

[0039] Examples include those represented by the following formula:

[0040] In the above formula, Z represents a divalent hydrocarbon group or a divalent hetero group. Examples of the divalent hydrocarbon group include an alkylene group having 1 to 10 carbon atoms or an arylene group having 6 to 10 carbon atoms, with an alkylene group having 1 to 5 carbon atoms being preferred, and an alkylene group having 1 to 3 carbon atoms being more preferred. Examples of the divalent hetero group include an alkyleneoxy group having 1 to 20 carbon atoms or an aryleneoxy group having 6 to 10 carbon atoms, with an alkyleneoxy group having 1 to 10 carbon atoms being preferred, an alkyleneoxy group having 1 to 5 carbon atoms being more preferred, and an alkyleneoxy group having 1 to 3 carbon atoms being even more preferred.

[0041] In the formula, each of the multiple R's independently represents a monovalent hydrocarbon group. The monovalent hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms.

[0042] In the formula (b), e is 0.45 to 0.98, preferably 0.50 to 0.95, and more preferably 0.70 to 0.90. f is 0 to 0.45, preferably 0 to 0.20, and more preferably 0 to 0.10. g is 0 to 0.10, and preferably 0.01 to 0.05. h is 0.01 to 0.15, and preferably 0.05 to 0.10. In the formula (b), e+f+g+h=1.

[0043] The weight-average molecular weight of the cyanated silicone polymer (B) must be 2000 or greater. If the weight-average molecular weight of the cyanated silicone polymer (B) is less than the lower limit, the elongation at break of the resulting crosslinked cyanated silicone elastomer will be reduced. Furthermore, it may be difficult to easily form the crosslinked cyanated silicone elastomer into a thin film. From the viewpoints of improving the elongation at break of the resulting crosslinked cyanated silicone elastomer and facilitating the formation of a thin film of the crosslinked cyanated silicone elastomer, the weight-average molecular weight of the cyanated silicone polymer (B) is preferably 5000 or greater. There is no particular upper limit to the weight-average molecular weight of the cyanated silicone polymer (B). However, since a larger molecular weight of the polymer tends to increase viscosity and make handling difficult, a weight-average molecular weight of 100,000 or less is preferred, and 50,000 or less is even more preferred.

[0044] Such a cyclic carbonate-modified silicone polymer (B) can be prepared by reacting silane monomers corresponding to each structural unit using a known method.

[0045] (Crosslinkable cyanidated silicone composition) The crosslinkable cyanated silicone composition of the present invention contains the high-molecular-weight linear cyanated silicone polymer (A) having vinyl groups and the high-molecular-weight linear cyanated silicone polymer (B) having hydrosilyl groups. In the crosslinkable cyanated silicone composition, the ratio of the vinyl group moiety (a) in the cyanated silicone polymer (A) to the hydrosilyl group equivalent (b) in the cyanated silicone polymer (B) is preferably b / a = 5 / 1 to 1 / 5, more preferably b / a = 2 / 1 to 1 / 2, and even more preferably b / a = 1 / 1. If the ratio of the vinyl group moiety (a) to the hydrosilyl group equivalent (b) is below the lower limit or exceeds the upper limit, poor curing tends to occur.

[0046] The crosslinkable cyanated silicone composition of the present invention may also contain a solvent, such as acetone, xylene, acetonitrile, tetrahydrofuran, or chloroform.

[0047] Furthermore, the crosslinkable cyanated silicone composition of the present invention may contain a crosslinking catalyst. Examples of the crosslinking catalyst include platinum group catalysts such as platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex. By heating the crosslinkable cyanated silicone composition containing such a crosslinking catalyst, the cyanated silicone polymer (A) and the cyanated silicone polymer (B) are thermally cured, resulting in the crosslinked cyanated silicone elastomer of the present invention.

[0048] The crosslinkable cyanated silicone composition of the present invention contains two types of cyanated silicone polymers with the same or similar basic skeletons, and therefore can be easily mixed uniformly to easily form a uniform crosslinked product (crosslinked cyanated silicone elastomer).

[0049] [Crosslinked cyanated silicone elastomer] Next, the crosslinked cyanated silicone elastomer of the present invention will be described. The crosslinked cyanated silicone elastomer of the present invention is a hydrosilylation reaction product of the crosslinkable cyanated silicone composition of the present invention. This hydrosilylation reaction product is preferably one (crosslinked product) obtained by crosslinking the cyanated silicone polymer (A) and the cyanated silicone polymer (B) using the crosslinking catalyst (preferably a platinum group catalyst). This crosslinked product has a crosslinked structure formed by covalent bonding between the vinyl groups of the cyanated silicone polymer (A) and the hydrosilyl groups of the cyanated silicone polymer (B) through the action of the crosslinking catalyst.

[0050] In the crosslinked cyanated silicone elastomer of the present invention, since the polysiloxane has a glass transition temperature lower than room temperature, the polysiloxane structure, which is the silicone's main chain skeleton, has high mobility at room temperature, and there is no factor that inhibits the orientation of functional groups by an electric field, so it is thought that large orientation polarization can be obtained.In addition, since the polysiloxane structure, which is the silicone's main chain skeleton, is flexible and has excellent mobility, it is presumed that crosslinking the crosslinkable cyanated silicone composition of the present invention will result in a crosslinked cyanated silicone elastomer with a low elastic modulus.Furthermore, since the polysiloxane structure, which is the silicone's main chain skeleton, has high electrical insulation properties, it is thought that it will exhibit high electrical resistance even if cyano groups, which have high polarization, are introduced into the side chain.

[0051] Furthermore, in the crosslinked cyanated silicone elastomer of the present invention, as described above, an alkylsilicone structure is formed as the crosslinked structure by the hydrosilylation reaction, making it possible to crosslink the crosslinkable cyanated silicone composition without forming a crosslinked structure that would reduce insulating properties.As a result, it is believed that the resulting crosslinked cyanated silicone elastomer exhibits high electrical resistance. [Example]

[0052] The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0053] (Synthesis Example A1) <Synthesis of high molecular weight linear cyanated silicone polymers containing vinyl groups> Under a nitrogen atmosphere, a 20 ml Schlenk tube was charged with 1.38 g (8.0 mmol) of 3-cyanopropylmethyldimethoxysilane, 240 mg (2.0 mmol) of dimethoxydimethylsilane, 130 mg (1.0 mmol) of dimethylethoxyvinylsilane, and 2 ml of 2-propanol, and the resulting solution was cooled in an ice bath at −10° C. for 10 minutes. To this solution was added an ice-cooled concentrated aqueous sulfuric acid solution (49 μl of sulfuric acid / 510 μl of water), and the mixture was stirred at −10° C. for 30 minutes and then at room temperature for 3 hours to obtain the compound represented by the following formula:

[0054] [ka]

[0055] The reaction represented by the formula below was carried out. The resulting reaction solution was stirred for 3 hours while evacuating at room temperature. It was then ice-cooled to 0°C and neutralized with a phosphate buffer solution (pH: approximately 6, concentration: approximately 1 M). 16 ml of ethyl acetate and 4 ml of water were added to the neutralized solution, and the reaction product was extracted into an organic phase. The solution was then centrifuged at 4800 rpm for 10 minutes to remove the aqueous phase. Approximately 4 ml of water was added to the resulting organic phase, and the organic phase was washed with water. The aqueous phase was then centrifuged at 4800 rpm for 10 minutes to remove the aqueous phase. This water washing process was repeated three times, and the solvent was then removed using a rotary evaporator. The resulting oily substance was dried overnight in vacuo to yield 1.14 g of a colorless, transparent, oily linear cyanated silicone polymer having vinyl groups.

[0056] 5 mg of the obtained silicone polymer was dissolved in 2.0 ml of chloroform and filtered through a filter with a pore size of 0.2 μm. Then, gel permeation chromatography (GPC, solvent: chloroform, detector: refractometer) was performed to determine the polystyrene-equivalent molecular weight distribution and weight average molecular weight (MW) of the silicone polymer. These results are shown in Figure 1 and Table 1.

[0057] Furthermore, the obtained silicone polymer 1 H-NMR measurements were performed to determine the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal vinyl-containing structural units, and terminal vinyl-containing structural units in the polymer, as well as the vinyl group equivalent. The results are shown in Table 1.

[0058] (Synthesis example A2) <Synthesis of high molecular weight linear cyanated silicone polymers containing vinyl groups> A compound of the following formula:

[0059] [ka]

[0060] The reaction shown in the following formula was carried out, yielding 882 mg of a colorless, oily, linear cyanidated silicone polymer having vinyl groups.

[0061] The resulting silicone polymer was analyzed in the same manner as in Synthesis Example A1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal vinyl-containing structural units, and terminal vinyl-containing structural units, and the vinyl equivalent weight. The results are shown in Figure 2 and Table 1.

[0062] (Synthesis example A3) <Synthesis of high molecular weight linear cyanated silicone polymers containing vinyl groups> A compound of the following formula:

[0063] [ka]

[0064] The reaction shown in the following formula was carried out, yielding 1.41 g of a colorless, oily, linear cyanidated silicone polymer having vinyl groups.

[0065] The resulting silicone polymer was analyzed in the same manner as in Synthesis Example A1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal vinyl-containing structural units, and terminal vinyl-containing structural units, and the vinyl equivalent weight. The results are shown in Figure 2 and Table 1.

[0066] (Synthesis example A4) <Synthesis of high molecular weight linear cyanated silicone polymers containing vinyl groups> A compound of the following formula:

[0067] [ka]

[0068] The reaction shown in the following formula was carried out, yielding 1.49 g of a pale yellow, transparent, oily linear cyanated silicone polymer having vinyl groups.

[0069] The resulting silicone polymer was analyzed in the same manner as in Synthesis Example A1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal vinyl-containing structural units, and terminal vinyl-containing structural units, and the vinyl equivalent weight. The results are shown in Figure 2 and Table 1.

[0070] (Synthesis example A5) <Synthesis of high molecular weight linear cyanated silicone polymers containing vinyl groups> The same procedures as in Synthesis Example A1 were repeated except that 467 mg (2.7 mmol) of 3-cyanopropylmethyldimethoxysilane and 130 mg (1.0 mmol) of dimethylethoxyvinylsilane were used, 39.6 mg (0.3 mmol) of dimethoxymethylvinylsilane was used instead of dimethoxydimethylsilane, the amount of 2-propanol was changed to 0.5 mL, the amount of concentrated sulfuric acid in the concentrated sulfuric acid aqueous solution was changed to 11 μL, the amount of water was changed to 139 μL, the amounts of ethyl acetate and water used during extraction were changed to 4 mL and 1 mL, and the amount of water used during washing was changed to approximately 1 mL, to obtain a compound of the following formula:

[0071] [ka]

[0072] The reaction shown in the following formula was carried out, and 343 mg of a pale yellow, transparent, oily linear cyanated silicone polymer having vinyl groups was obtained.

[0073] The resulting silicone polymer was analyzed in the same manner as in Synthesis Example A1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal vinyl-containing structural units, and terminal vinyl-containing structural units, and the vinyl equivalent weight. The results are shown in Figure 2 and Table 1.

[0074] (Comparative Synthesis Example A1) <Synthesis of low molecular weight linear cyanated silicone polymers containing vinyl groups> An oily, colorless, and transparent linear cyanated silicone polymer bearing vinyl groups was obtained in the same manner as in Synthesis Example A1, except that the resulting solution was not vacuumed after the reaction represented by the above formula. The resulting silicone polymer was subjected to the same procedures as in Synthesis Example A1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal vinyl-containing structural units, and terminal vinyl-containing structural units, and the vinyl group equivalent. The results are shown in Figure 1 and Table 1.

[0075] (Comparative synthesis example A2) <Synthesis of linear dimethylsilicone polymers containing vinyl groups> A compound of the following formula:

[0076] [ka]

[0077] The reaction shown in the following formula was carried out, and 360 mg of a colorless, transparent, oily linear dimethyl silicone polymer having vinyl groups was obtained.

[0078] The resulting silicone polymer was analyzed in the same manner as in Synthesis Example A1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal vinyl-containing structural units, and terminal vinyl-containing structural units, and the vinyl equivalent weight. The results are shown in Figure 3 and Table 1.

[0079] [Table 1]

[0080] As shown in Table 1, it was confirmed that the weight average molecular weight (MW) of the linear cyanated silicone polymer having a vinyl group-containing structural unit can be increased to 1,000 or more by evacuation.

[0081] Furthermore, when a cyanated silanol ester was not used as a raw material monomer (Comparative Synthesis Example A2), it was confirmed that the weight average molecular weight (MW) did not increase significantly even when vacuum drawing was performed, compared to when a cyanated silanol ester was used (Synthesis Examples A1 to A5).

[0082] (Synthesis Example B1) <Synthesis of high molecular weight linear cyanated silicone polymers containing hydrosilyl groups> Under a nitrogen atmosphere, 7.53 g (43 mmol) of 3-cyanopropylmethyldimethoxysilane, 1.42 g (12 mmol) of dimethoxydimethylsilane, 1.05 g (10 mmol) of dimethoxy(methyl)silane, 3 ml (22 mmol) of ethoxydimethylsilane, and 10 ml of 2-propanol were placed in a 100 ml Schlenk flask and cooled for 10 minutes in an ice bath at −10° C. To this solution was added an ice-cooled concentrated aqueous sulfuric acid solution (0.27 ml of sulfuric acid / 2.7 ml of water), and the mixture was stirred at −10° C. for 30 minutes and then at room temperature for 3 hours to obtain the compound of the following formula:

[0083] [ka]

[0084] The reaction represented by the formula below was carried out. The resulting reaction solution was stirred for 2 hours while evacuating at room temperature. It was then ice-cooled to 0°C and neutralized with a phosphate buffer solution (pH: approximately 6, concentration: approximately 1 M). 80 ml of ethyl acetate and 20 ml of water were added to the neutralized solution, and the reaction product was extracted into an organic phase. The aqueous phase was then removed by centrifugation at 4800 rpm for 10 minutes. Approximately 20 ml of water was added to the resulting organic phase, and the organic phase was washed with water. The aqueous phase was then removed by centrifugation at 4800 rpm for 10 minutes. This water washing process was repeated a total of three times, and the solvent was then distilled off using a rotary evaporator. The resulting oily substance was dried under vacuum overnight, yielding 6.71 g of a colorless, transparent, oily linear cyanated silicone polymer.

[0085] 5 mg of the obtained silicone polymer was dissolved in 2.0 ml of chloroform and filtered through a filter with a pore size of 0.2 μm. Then, gel permeation chromatography (GPC, solvent: chloroform, detector: refractometer) was performed to determine the polystyrene-equivalent molecular weight distribution and weight average molecular weight (MW) of the silicone polymer. These results are shown in Figure 4 and Table 2.

[0086] Furthermore, the obtained silicone polymer 1H-NMR measurements were carried out to determine the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal hydrosilyl-containing structural units, and terminal hydrosilyl-containing structural units in the polymer, as well as the hydrosilyl group equivalent. These results are shown in Table 2.

[0087] (Synthesis example B2) <Synthesis of high molecular weight linear cyanated silicone polymers containing hydrosilyl groups> The same procedures as in Synthesis Example B1 were repeated except that a 20 mL Schlenk flask was used instead of a 100 mL Schlenk flask, 779 mg (4.5 mmol) of 3-cyanopropylmethyldimethoxysilane, 540 mg (4.5 mmol) of dimethoxydimethylsilane, 106 mg (1.0 mmol) of dimethoxy(methyl)silane, and 550 μL (4.0 mmol) of ethoxydimethylsilane were used, the amount of 2-propanol was changed to 2 mL, the amount of concentrated sulfuric acid in the concentrated sulfuric acid aqueous solution was changed to 49 μL, the amount of water was changed to 510 μL, the time for stirring under vacuum was changed to 3 hours, the amounts of ethyl acetate and water used during extraction were changed to 16 mL and 4 mL, and the amount of water used during washing was changed to approximately 4 mL, to obtain a product of the following formula:

[0088] [ka]

[0089] The reaction shown in the following formula was carried out, and 917 mg of a colorless, transparent, oily linear cyanated silicone polymer having hydrosilyl groups was obtained.

[0090] The resulting silicone polymer was subjected to the same procedures as in Synthesis Example B1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal hydrosilyl-containing structural units, and terminal hydrosilyl-containing structural units, and the hydrosilyl group equivalent. These results are shown in Figure 5 and Table 2.

[0091] (Synthesis Example B3) <Synthesis of high molecular weight linear cyanated silicone polymers containing hydrosilyl groups> The same procedures as in Synthesis Example B1 were repeated except that a 20 mL Schlenk flask was used instead of a 100 mL Schlenk flask, 2.07 g (12 mmol) of 3-cyanopropylmethyldimethoxysilane and 480 μL (3.5 mmol) of ethoxydimethylsilane were used, dimethoxydimethylsilane and dimethoxy(methyl)silane were not used, the amount of 2-propanol was changed to 2 mL, the amount of concentrated sulfuric acid in the concentrated sulfuric acid aqueous solution was changed to 49 μL, the amount of water was changed to 510 μL, the amounts of ethyl acetate and water during extraction were changed to 16 mL and 4 mL, and the amount of water during washing was changed to approximately 4 mL, to obtain a compound of the following formula:

[0092] [ka]

[0093] The reaction shown in the following formula was carried out, yielding 1.51 g of a colorless, oily, linear cyanated silicone polymer having hydrosilyl groups.

[0094] The resulting silicone polymer was subjected to the same procedures as in Synthesis Example B1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal hydrosilyl-containing structural units, and terminal hydrosilyl-containing structural units, and the hydrosilyl group equivalent. These results are shown in Figure 5 and Table 2.

[0095] (Synthesis example B4) <Synthesis of high molecular weight linear cyanated silicone polymers containing hydrosilyl groups> The same procedures as in Synthesis Example B1 were repeated except that a 20 mL Schlenk flask was used instead of a 100 mL Schlenk flask, 415 mg (2.4 mmol) of 3-cyanopropylmethyldimethoxysilane, 64 mg (0.6 mmol) of dimethoxy(methyl)silane, and 120 μL (0.87 mmol) of ethoxydimethylsilane were used, no dimethoxydimethylsilane was used, the amount of 2-propanol was changed to 0.5 mL, the amount of concentrated sulfuric acid in the concentrated sulfuric acid aqueous solution was changed to 11 μL, the amount of water was changed to 139 μL, the amounts of ethyl acetate and water used during extraction were changed to 4 mL and 1 mL, and the amount of water used during washing was changed to approximately 1 mL, to obtain a compound of the following formula:

[0096] [ka]

[0097] The reaction shown in the following formula was carried out, and 300 mg of a colorless, oily, linear cyanated silicone polymer having hydrosilyl groups was obtained.

[0098] The resulting silicone polymer was subjected to the same procedures as in Synthesis Example B1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal hydrosilyl-containing structural units, and terminal hydrosilyl-containing structural units, and the hydrosilyl group equivalent. These results are shown in Figure 5 and Table 2.

[0099] (Synthesis Example B5) <Synthesis of high molecular weight linear cyanated silicone polymers containing hydrosilyl groups> The same procedures as in Synthesis Example B1 were repeated except that a 20 mL Schlenk flask was used instead of a 100 mL Schlenk flask, 467 mg (2.7 mmol) of 3-cyanopropylmethyldimethoxysilane, 32 mg (0.3 mmol) of dimethoxy(methyl)silane, and 120 μL (0.87 mmol) of ethoxydimethylsilane were used, no dimethoxydimethylsilane was used, the amount of 2-propanol was changed to 0.5 mL, the amount of concentrated sulfuric acid in the concentrated sulfuric acid aqueous solution was changed to 11 μL, the amount of water was changed to 139 μL, the amounts of ethyl acetate and water used during extraction were changed to 4 mL and 1 mL, and the amount of water used during washing was changed to approximately 1 mL, to obtain a compound of the following formula:

[0100] [ka]

[0101] The reaction shown in the following formula was carried out, yielding 345 mg of a colorless, oily, linear cyanated silicone polymer having hydrosilyl groups.

[0102] The resulting silicone polymer was subjected to the same procedures as in Synthesis Example B1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal hydrosilyl-containing structural units, and terminal hydrosilyl-containing structural units, and the hydrosilyl group equivalent. These results are shown in Figure 5 and Table 2.

[0103] (Comparative Synthesis Example B1) <Synthesis of low molecular weight linear cyanated silicone polymers with hydrosilyl groups> After the reaction represented by the above formula, a colorless, transparent, oily linear cyanated silicone polymer was obtained in the same manner as in Synthesis Example B1, except that the resulting solution was not evacuated. The molecular weight distribution and weight average molecular weight (MW) of the resulting silicone polymer, calculated in terms of polystyrene, the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal hydrosilyl-containing structural units, and terminal hydrosilyl-containing structural units, and the hydrosilyl group equivalent were determined in the same manner as in Synthesis Example B1. The results are shown in Figure 4 and Table 2.

[0104] (Comparative synthesis example B2) <Synthesis of branched cyanated silicone polymers containing hydrosilyl groups> The same procedure as in Synthesis Example B1 was repeated, except that a 20 ml Schlenk flask was used instead of a 100 ml Schlenk flask, 104 mg (0.6 mmol) of 3-cyanopropylmethyldimethoxysilane, 32 mg (0.3 mmol) of dimethoxy(methyl)silane, and 60 μl (0.5 mmol) of ethoxydimethylsilane were used, 555 mg (2.4 mmol) of 3-cyanopropyltriethoxysilane was used instead of dimethoxydimethylsilane, the amount of 2-propanol was changed to 0.5 ml, the amount of concentrated sulfuric acid in the concentrated sulfuric acid aqueous solution was changed to 12 μl, and the amount of water was changed to 128 μl, to obtain a compound of the following formula:

[0105] [ka]

[0106] The reaction represented by the following formula was carried out. The resulting reaction solution was stirred at room temperature while being evacuated, and gelation occurred within 2 hours.

[0107] These results indicate that when a trifunctional silanol ester is used as a raw material monomer, gelation occurs during the preparation stage of the branched-chain cyanated silicone polymer, making it impossible to obtain a crosslinkable cyanated silicone composition or crosslinked cyanated silicone elastomer.

[0108] (Comparative synthesis example B3) <Synthesis of Linear Dimethylsilicone Polymer with Hydrosilyl Groups> The same procedures as in Synthesis Example B1 were repeated except that a 20 mL Schlenk flask was used instead of a 100 mL Schlenk flask, 1080 mg (9.0 mmol) of dimethoxydimethylsilane, 106 mg (1.0 mmol) of dimethoxy(methyl)silane, and 550 μL (4.0 mmol) of ethoxydimethylsilane were used, 3-cyanopropylmethyldimethoxysilane was not used, the amount of 2-propanol was changed to 2 mL, the amount of concentrated sulfuric acid in the concentrated sulfuric acid aqueous solution was changed to 49 μL, the amount of water was changed to 510 μL, the amounts of ethyl acetate and water used during extraction were changed to 16 mL and 4 mL, and the amount of water used during washing was changed to approximately 4 mL, to obtain a compound represented by the following formula:

[0109] [ka]

[0110] The reaction shown in the following formula was carried out, and 409 mg of a colorless, transparent, oily linear dimethylsilicone polymer having hydrosilyl groups was obtained.

[0111] The resulting silicone polymer was subjected to the same procedures as in Synthesis Example B1 to determine its polystyrene-equivalent molecular weight distribution and weight-average molecular weight (MW), the proportions of cyano-containing structural units, methyl-containing structural units, non-terminal hydrosilyl-containing structural units, and terminal hydrosilyl-containing structural units, and the hydrosilyl group equivalent. The results are shown in Figure 6 and Table 2.

[0112] [Table 2]

[0113] As shown in Table 2, it was confirmed that the weight average molecular weight (MW) of the linear cyanated silicone polymer having structural units containing hydrosilyl groups became 2000 or more by evacuation.

[0114] Furthermore, when a cyanated silanol ester was not used as a raw material monomer (Comparative Synthesis Example B3), it was confirmed that the weight average molecular weight (MW) did not increase significantly even when vacuum drawing was performed, compared to when a cyanated silanol ester was used (Synthesis Examples B1 and B2).

[0115] Example 1 A crosslinkable silicone composition solution was prepared by mixing and stirring 41 mg of the linear cyanated silicone polymer (MW: 3800) having structural units containing vinyl groups obtained in Synthesis Example A5, 102 mg of the linear cyanated silicone polymer (MW: 9500) having structural units containing hydrosilyl groups obtained in Synthesis Example B5, 2 μl of a solution (Pt amount: 0.027 μmol) of a platinum catalyst (a xylene solution of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane complex (Karstedt catalyst manufactured by Aldrich, Pt amount: approximately 2% by mass) diluted 1 / 10 with xylene, and 700 μl of tetrahydrofuran (THF). 600 μl of the resulting crosslinkable silicone composition solution was applied to an aluminum substrate using a spin coater. The resulting coating was heated at 70°C for 10 hours under a nitrogen atmosphere to form a compound represented by the following formula:

[0116] [ka]

[0117] A crosslinked high molecular weight cyanated silicone elastomer film (size: 20 mm square, thickness: 200 μm) was produced by the thermal curing reaction represented by the following formula:

[0118] A 10 mm x 5 mm strip test piece was cut out from this crosslinked high molecular weight cyanated silicone elastomer film, and the breaking elongation of the film was measured using a dynamic viscoelasticity measuring device (MCR301, manufactured by Anton Paar), which was found to be 40% or more.

[0119] In addition, a thin Au film (thickness: 100 nm) was formed on both sides of the obtained crosslinked high molecular weight cyanated silicone elastomer film by magnetron sputtering, and the relative dielectric constant of the film was measured at a frequency of 1 kHz using an impedance analyzer (Keysight "HP4194A"), which was found to be 12.

[0120] (Comparative Example 1) A crosslinked low molecular weight cyanated silicone elastomer film (size: 20 mm square, thickness: 150 μm) was prepared in the same manner as in Example 1, except that 59 mg of the linear cyanated silicone polymer (MW: 8300) having structural units containing vinyl groups obtained in Synthesis Example A3 was used instead of the linear cyanated silicone polymer (MW: 3800) having structural units containing vinyl groups, 60 mg of the linear cyanated silicone polymer (MW: 1800) having structural units containing hydrosilyl groups obtained in Comparative Synthesis Example B1 was used instead of the linear cyanated silicone polymer (MW: 9500) having structural units containing hydrosilyl groups, and the amount of THF was changed to 400 μl.

[0121] A 10 mm x 5 mm strip test piece was cut out from this crosslinked low molecular weight cyanated silicone elastomer film, and the breaking elongation of the film was measured using a dynamic viscoelasticity measuring device (MCR301, manufactured by Anton Paar), which was found to be 20%. [Industrial Applicability]

[0122] As explained above, the crosslinkable cyanated silicone composition of the present invention makes it possible to form a crosslinked cyanated silicone elastomer that has a high dielectric constant and excellent elongation at break.

[0123] Therefore, the crosslinked cyanated silicone elastomer of the present invention can be used as a dielectric elastomer layer in an electronic device by forming electrodes on both sides of the film. Such an electronic device can be used as an actuator, for example, by applying a voltage to change the distance between the electrodes. Furthermore, for example, when pressure is applied to cause deformation, the distance between the electrodes changes, resulting in a change in impedance, allowing the device to be used as a pressure sensor, for example. In particular, the crosslinked cyanated silicone elastomer of the present invention has a high dielectric constant, making it useful as a dielectric elastomer layer in high-performance actuators and high-sensitivity sensors.

Claims

1. a linear cyanated silicone polymer (A) having a weight average molecular weight of 1,000 or greater and containing a structural unit containing a vinyl group and a structural unit containing a cyano group in a side chain; a linear cyanated silicone polymer (B) having a weight average molecular weight of 2000 or more and containing a structural unit containing a hydrosilyl group and a structural unit containing a cyano group in a side chain; A crosslinkable cyanated silicone composition comprising:

2. 2. The crosslinkable cyanated silicone composition according to claim 1, wherein the cyanated silicone polymer (A) has a structural unit containing a vinyl group at least at the terminal thereof.

3. 2. The crosslinkable cyanated silicone composition according to claim 1, wherein the cyanated silicone polymer (B) has structural units containing hydrosilyl groups at least at the terminals.

4. 2. The crosslinkable cyanated silicone composition according to claim 1, wherein the weight-average molecular weight of the cyanated silicone polymer (A) is 3,000 or more.

5. 2. The crosslinkable cyanated silicone composition according to claim 1, wherein the weight-average molecular weight of the cyanated silicone polymer (B) is 5,000 or more.

6. The cyanated silicone polymer (A) is represented by the following formula (a): 【Chemical 1】 [In the above formula, Z represents either a divalent hydrocarbon group or a divalent hetero group; each of the multiple Rs independently represents a monovalent hydrocarbon group; a is 0.45 to 0.98; b is 0 to 0.50; c is 0 to 0.15; d is 0.01 to 0.20; and a+b+c+d=1.] It is expressed as The cyanated silicone polymer (B) is represented by the following formula (b): 【Chemistry 2】 [In the above formula, Z represents either a divalent hydrocarbon group or a divalent hetero group; each of the multiple Rs independently represents a monovalent hydrocarbon group; e is 0.45 to 0.98; f is 0 to 0.45; g is 0 to 0.10; h is 0.01 to 0.15; and e+f+g+h=1.] It is expressed as The crosslinkable cyanated silicone composition according to claim 1 .

7. A hydrosilylation reaction product of the crosslinkable cyanated silicone composition according to any one of claims 1 to 6, A crosslinked cyanated silicone elastomer, characterized in that a vinyl group of the cyanated silicone polymer (A) and a hydrosilyl group of the cyanated silicone polymer (B) form a covalent bond.

8. 8. The crosslinked cyanated silicone elastomer according to claim 7, wherein the hydrosilylation reaction product is a product crosslinked with a platinum group catalyst.

Images