Curable silicone composition

Abstract

This disclosure relates to a curable polysiloxane composition comprising: (A) an organopolysiloxane resin having an alkenyl group in the molecule; (B) an organosiloxane oligomer with a viscosity not exceeding 1,000 mPa·s at 25°C, having at least one silicon atom bonded to an alkenyl group or a silicon atom bonded to a hydrogen atom in the molecule, and having at least one silicon atom bonded to an aryl group; (C) an organopolysiloxane having at least one alkenyl group in the molecule but not having a silicon atom bonded to an aryl group or a SiO4 / 2 unit, or an organopolysiloxane having at least one silicon atom bonded to a hydrogen atom in the molecule but not having a silicon atom bonded to an aryl group; (D) a silica filler; and (E) a hydrosiliconization catalyst. Although this composition contains a large amount of organopolysiloxane resin, it exhibits excellent thixotropic properties and can be cured to form a transparent cured product.

Description

Curable polysiloxane composition This invention relates to a curable polysiloxane composition. Curable polysiloxane compositions include: (CH) 3) 3SiO 1 / 2 Unit, CH 2=CH(CH 3) SiO 2 / 2 Unit and SiO 4 / 2 The invention comprises an organopolysiloxane resin; an organopolysiloxane having at least two silicon atoms bonded to hydrogen atoms in its molecule; and a curable polysiloxane composition with a hydrosilylation catalyst, wherein the curable polysiloxane composition is cured to form a transparent cured product with excellent heat resistance, electrical insulation properties, and weather resistance. Therefore, curable polysiloxane compositions are widely used as protective coatings, encapsulation materials, or sealants for electrical / electronic devices. In a particular application, the thixotropic properties of the curable polysiloxane composition are required to control flowability and maintain its shape after dispensing. For example, Patent Document 1 discloses a curable polysiloxane composition in Example 1, which comprises: CH 2=CH(CH 3) 2SiO 1 / 2 Unit, (CH) 3) 3SiO 1 / 2 Unit and SiO 4 / 2 The composition includes an organic polysiloxane resin; a vinyl-terminated dimethyl polysiloxane; a methylhydropolysiloxane; and a platinum catalyst. Patent document 1 also discloses that inorganic fillers, such as smog silica, are used to enhance strength without compromising transparency. However, patent document 1 does not concern enhancing the thixotropic properties of curable polysiloxane compositions. Patent document 2 discloses a curable polysiloxane composition in Example 4, comprising: a copolymer of dimethylsiloxane and methylvinylsiloxane, both molecular chains end-capped with dimethylvinylsiloxy groups; and CH 2=CH(CH 3) 2SiO 1 / 2 Unit, (CH) 3) 3SiO 1 / 2 Unit and SiO 4 / 2 The unit is composed of organic polysiloxane resin; made of (CH) 3) 2HSiO 1 / 2 Unit and SiO 4 / 2 The composition comprises a methylhydrogen polysiloxane; a platinum catalyst; and silica fume. The curable polysiloxane composition is then cured to form a low-transparency cured product. Patent document 2 also discloses a curable polysiloxane composition in Example 5, comprising: a copolymer of dimethylsiloxane and diphenylsiloxane capped at both ends of the molecular chains with dimethylvinylsiloxy groups; and CH... 2=CH(CH 3) 2SiO 1 / 2 Unit, (CH) 3) 3SiO 1 / 2 Unit and SiO 4 / 2 The unit is composed of organic polysiloxane resin; made of (CH) 3) 2HSiO 1 / 2 Unit and SiO 4 / 2 The unit composition is a methylhydropolysiloxane; and a platinum catalyst. However, Patent Document 2 does not relate to enhancing the thixotropic properties of the curable polysiloxane composition. Patent document 3 discloses a curable polysiloxane composition in Example 1, comprising: a copolymer of dimethylsiloxane and diphenylsiloxane capped at the ends of two molecular chains with trivinylsiloxy groups; and CH 2=CH(CH 3) 2SiO 1 / 2 Unit, (CH) 3) 3SiO 1 / 2 Unit and SiO 4 / 2 The unit is composed of organic polysiloxane resin; made of (CH) 3) 2HSiO 1 / 2 Unit and SiO 4 / 2 The composition comprises a polymethylhydrosiloxane; a methylhydrosiloxane capped with trimethylsiloxy groups at both ends of its molecular chains; a platinum catalyst; smog silica; and an organopolysiloxane with epoxypropoxypropyl groups as a thixotropic agent. The curable polysiloxane composition is cured to form a transparent cured product, but its thixotropic properties are inferior compared to compositions using copolymers of dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both ends of its molecular chains instead of dimethylsiloxane and diphenylsiloxane. Patent document 4 discloses, in examples, a curable polysiloxane composition comprising: a copolymer of dimethylsiloxane and diphenylsiloxane, both molecular chains end-capped with dimethylvinylsiloxy groups; and (CH... 3) 3SiO 1 / 2 Unit, CH 2=CH(CH 3) SiO 2 / 2 Unit and SiO 4 / 2 The unit is composed of organic polysiloxane resin; made of (CH) 3) 2HSiO 1 / 2 Unit and SiO 4 / 2 The composition includes organohydrosiloxanes; or copolymers of methylhydrosiloxanes and dimethylsiloxanes with trimethylsiloxy groups at the ends of both molecular chains; a platinum catalyst; and fuming silica. These curable polysiloxane compositions exhibit thixotropic properties and cure to form a transparent cured product. However, organohydrosiloxane resins require the presence of R... 2SiO 2 / 2 The unit, wherein each R independently represents an alkenyl group or an alkyl group that may be halogenated. Furthermore, the amount of the organopolysiloxane resin, based on the total amount of the linear organopolysiloxane and the organopolysiloxane resin, is limited to 10 to 40% by mass. (Previous technical documents, patent documents) Patent Document 1: U.S. Patent Application Publication No. 2004 / 0116640 A1; Patent Document 2: Japanese Patent Application Publication No. 2006-335857 A; Patent Document 3: Korean Patent Application Publication No. 10-2009-0103785 A; Patent Document 4: Korean Patent Application Publication No. 10-2015-0065672 A. Technical issues The objective of this invention is to provide a curable polysiloxane composition that, despite containing a large amount of organopolysiloxane resin, exhibits excellent thixotropic properties and can be cured to form a transparent cured product. Solution to the problem The curable polysiloxane composition of the present invention comprises: (A) an organopolysiloxane resin represented by the following average unit formula: (R) 1 3SiO 1 / 2 ) a (R 2 R 1 2SiO 1 / 2 ) b (SiO 4 / 2 ) c (HO 1 / 2 ) d Among them, each R 1 Independent alkyl groups; R 2 Alkenyl groups; and "a", "b", "c", and "d" are values ​​that satisfy the following conditions: a ≥ 0, b > 0, 0.3 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1; (B) Viscosities at 25°C not greater than 1,000 mPa·s and selected from the following organosiloxane oligomers: (B 1) Organosiloxane oligomers having at least one silicon atom bonded to an alkenyl group and at least one silicon atom bonded to an aryl group in the molecule; (B) 2) Organosiloxane oligomers having at least one silicon atom bonded to a hydrogen atom and at least one silicon atom bonded to an aryl group in the molecule; and component (B) 1) with component (B) 2) A mixture thereof; (C) Selected from the following organopolysiloxanes: (C 1) The molecule contains at least one alkenyl group and does not have silicon atoms bonded to aryl groups or SiO2. 4 / 2 Organic polysiloxanes of unit; (C 2) An organopolysiloxane having at least one silicon atom bonded to a hydrogen atom and no silicon atom bonded to an aryl group in the molecule; and component (C 1) with component (C) 2) a mixture; (D) a silica filler; and (E) a catalytic amount of a silicon hydrogenation catalyst; wherein the amount of component (A) is in the range of 40.0 to 65.0% by mass, the amount of component (B) is in the range of 1.0 to 55.0% by mass, and the amount of component (C) is in the range of 0 to 50.0% by mass, each based on the total mass of components (A) to (C), and the amount of component (D) is in the range of 1 to 10 parts by mass relative to 100 parts by mass of the total mass of components (A) to (C), subject to the limitation that the molar ratio of all silicon atoms bonded to hydrogen atoms relative to all silicon atoms bonded to alkenyl groups in components (A) to (C) is in the range of 0.5 to 2.0. In various embodiments, component (B) 1) is selected from at least one of the following: (B) 11 Organosiloxane oligomers represented by the following general formula: R 2 R 3 2SiO(R 3 2SiO) m SiR 3 2R 2 Among them, each R 2 Independent geosystem alkenyl groups; each R 3 Independently alkyl or aryl, with the restriction that at least one R 3 It is an aryl group; and "m" is an integer from 0 to 10, and (B 12 Organosiloxane oligomers represented by the following average unit formula: (R) 2 R 3 2SiO 1 / 2 ) e (R 3 SiO 3 / 2 ) f Where R 2 and R 3 As described above; and "e" and "f" are numerical values ​​that satisfy the following conditions: e > 0, f > 0, and e + f = 1. In various embodiments, component (B) 11 The group consists of at least one of the organosiloxane oligomers represented by the following formula: (CH 2=CH)(CH 3) 2SiO(C 6H 5) 2SiOSi(CH 3) 2(CH=CH 2) (CH 2=CH)(CH 3) 2SiO(C 6H 5)(CH 3) SiOSi(CH 3) 2(CH=CH 2) (CH 2=CH)(CH 3)(C 6H 5)SiOSi(CH 3)(C 6H 5)(CH=CH 2) And component (B) 12 ) refers to organosiloxane oligomers represented by the following general unit formula: [(CH 2=CH)(CH 3) 2SiO 1 / 2 ] e [(C 6H 5) SiO 3 / 2 ] f The "e" and "f" are as described above. In various embodiments, component (B) 2) It is selected from at least one of the following: (B) 21 Organosiloxane oligomers represented by the following general formula: HR 3 2SiO(R 3 2SiO) m SiR 3 2H, where each R 3 Independently alkyl or aryl, with the restriction that at least one R 3 It is an aryl group; and "m" is an integer from 0 to 10, and (B 22 Organosiloxane oligomers represented by the following average unit formula: (R) 3 2HSiO 1 / 2 ) e (R 3 SiO 3 / 2 ) f Where R 3 As described above; and "e" and "f" are numerical values ​​that satisfy the following conditions: e > 0, f > 0, and e + f = 1. In various embodiments, component (B) 21 The group consists of at least one of the organosiloxane oligomers represented by the following formula: H(CH) 3) 2SiO(C 6H 5) 2SiOSi(CH 3) 2H H(CH 3) 2SiO(C 6H 5)(CH 3) SiOSi(CH 3) 2H and component (B) 22 ) refers to organosiloxane oligomers represented by the following general unit formula: [(CH 3) 2HSiO 1 / 2 ] e [(C 6H 5) SiO 3 / 2 ] f The "e" and "f" are as described above. In various embodiments, the curable polysiloxane composition further comprises: (F) a silane hydrocracking reaction inhibitor, in an amount of 0.1 to 10,000 ppm relative to the composition by mass. In various embodiments, the curable polysiloxane composition further comprises: (G) an adhesion promoter, wherein the amount is at most 10 parts by weight relative to 100 parts by weight of the total mass of components (A) to (C). Effects of the Invention The curable polysiloxane composition of this invention, although containing a large amount of organopolysiloxane resin, possesses excellent thixotropic properties and can be cured to form a transparent cured product. Definition The term "comprising / comprise" is used in its broadest sense herein to mean and encompass the concepts of "including / include," "consisting essentially of," and "consisting of." The use of "for example," "eg," "such as," and "including" to indicate that illustrative examples are not limited to those listed. Therefore, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and covers similar or equivalent examples. The term "about" as used herein is used to reasonably encompass or describe minute variations in numerical values ​​measured by instrumental analysis or due to sample processing. These minute variations may be approximately within ±0 to 25, ±0 to 10, ±0 to 5, or ±0 to 2.5% of the numerical value. Furthermore, the term "approximately" applies to both values ​​within a range when it is used in relation to that range. Additionally, the term "approximately" may apply to numerical values ​​even when not explicitly stated otherwise. It should be understood that the appended claims are not limited to the specific compounds, compositions, or methods described in the embodiments, which may vary between specific embodiments falling within the scope of the appended claims. Regarding the Markush group upon which the specific features or forms of the various embodiments described in this specification are based, it should be understood that different, special, and / or unintended results may be obtained from and independent of all other Markush members. Individual and / or combined reliance on members of the Markush group may be sufficient to support specific embodiments falling within the scope of the appended claims. It should also be understood that any scope and subscopes upon which the various embodiments of the invention are described fall independently and collectively within the scope of the appended claims, and are to be understood as describing and contemplating all ranges including the whole and / or parts thereof, even if such values ​​are not explicitly stated herein. It will be readily recognized by those skilled in the art that the enumerated scopes and subscopes adequately describe and enable the various embodiments of the invention to be practiced, and that such scopes and subscopes may be further described as related bisections, trisections, quartices, quintices, etc. As an example only, the range "0.1 to 0.9" can be further divided into the lower third (i.e., 0.1 to 0.30), the middle third (i.e., 0.4 to 0.6), and the upper third (i.e., 0.7 to 0.9), which individually and collectively fall within the scope of the appended claims and can be relied upon individually and / or collectively, and will provide sufficient support for specific embodiments falling within the scope of the appended claims. Furthermore, language defining or modifying a range, such as "at least," "greater than," "less than," "no more than," and similar expressions, should be understood to include sub-ranges and / or upper or lower limits. As another example, a range of "at least 10" naturally includes sub-ranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., and can be adequately supported individually and / or collectively by each sub-range, and will provide sufficient support for specific embodiments falling within the scope of the appended claims. Finally, specific embodiments falling within the scope of the disclosed range can be adequately supported by individual figures, and will provide sufficient support for specific embodiments falling within the scope of the appended claims. For example, the range of "1 to 9" includes various individual integers such as 3, and individual numbers including decimal points (or fractions) such as 4.1, which can be relied upon and provide sufficient support for specific embodiments falling within the scope of the appended claims. The curable polysiloxane composition of the present invention will be explained in detail. Component (A) is an organopolysiloxane resin represented by the following average unit formula: (R) 1 3SiO 1 / 2 ) a (R 2 R 1 2SiO 1 / 2 ) b (SiO 4 / 2 ) c (HO 1 / 2 ) d . In some embodiments, each R 1 Alkyl groups are alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tributyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. Methyl is preferred. In this formula, R 2 Alkenyl groups are those having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl. Vinyl is preferred. In this formula, "a", "b", "c", and "d" are values ​​that satisfy the following conditions: a ≥ 0, b > 0, 0.3 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1. Alternatively, 0.1 ≤ a ≤ 0.5, 0.01 ≤ b ≤ 0.2, 0.4 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1. Or alternatively, 0.2 ≤ a ≤ 0.5, 0.01 ≤ b ≤ 0.2, 0.4 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1. This is because if the values ​​of "a", "b", "c" and "d" are within the range mentioned above, the cured product obtained by curing this composition will have appropriate hardness and mechanical strength. The molecular weight of the organopolysiloxane resin used in component (A) is not limited; however, its number average molecular weight (Mn) as measured by gel permeation chromatography (GPC) relative to standard polystyrene is preferably at least 1,500 g / mol, alternatively at least 2,000 g / mol, or alternatively at least 3,000 g / mol; while Mn is preferably not greater than 6,000 g / mol; alternatively not greater than 5,500 g / mol. The Mn of component (A) can be any range combining the above upper and lower limits. Note that if component (A) is solid at 25°C and it is difficult to uniformly mix the other components in the composition of the present invention, this can be achieved by pre-preparing an organic solution of component (A) and mixing it with some or all of components (B) and component (C), from which the organic solvent used can then be removed. Note that any organic solvent that can be used to prepare the organic solution of component (A) can be used, as long as the organic solvent can dissolve component (A) and is easily removed. Although not limited to these, specific examples include: aromatic hydrocarbons, such as toluene or xylene; and aliphatic hydrocarbons, such as hexane or heptane. Component (A) is used in an amount of 40.0 to 65.0% by mass, alternatively in an amount of 40.0 to 62.0% by mass, alternatively in an amount of 45.0 to 65.0% by mass, or alternatively in an amount of 45.0 to 62.0% by mass, each based on the total mass of components (A) to (C). This is because if the amount is equal to or higher than the lower limit of the above range, the cured product obtained by curing this composition will have suitable hardness and mechanical strength; however, if the amount is equal to or lower than the upper limit of the above range, the composition will have suitable viscosity at 25°C. Component (B) is an organosiloxane oligomer used to impart thixotropic properties to curable polysiloxane compositions and to impart transparency to the cured products obtained by curing the compositions. The molecular structure of the organosiloxane oligomer used in component (B) is not limited; however, examples include straight-chain, partially branched straight-chain, and branched oligomers. The molecular weight of the organosiloxane oligomer used in component (B) is not limited; however, it is preferably not greater than 2,000 g / mol, and alternatively not greater than 1,500 g / mol. This organosiloxane oligomer typically has a viscosity at 25°C not greater than 1,000 mPa·s, alternatively not greater than 500 mPa·s, or alternatively not greater than 100 mPa·s. Note that in this specification, viscosity is measured using a Type B viscometer according to ASTM D 1084 at 23 ± 2°C. The organosiloxane oligomer used in component (B) also acts as a chain extender and crosslinking agent for the composition, and is selected from: (B) 1) Organosiloxane oligomers having at least one silicon atom bonded to an alkenyl group and at least one silicon atom bonded to an aryl group in the molecule; (B) 2) Organosiloxane oligomers having at least one silicon atom bonded to a hydrogen atom and at least one silicon atom bonded to an aryl group in the molecule; and component (B) 1) with component (B) 2) A mixture of these. For component (B) 1) The organosiloxane oligomers are typically selected from at least one of the following: (B) 11 Organosiloxane oligomers represented by the following general formula: R 2 R 3 2SiO(R 3 2SiO) m SiR 3 2R 2 and (B) 12 Organosiloxane oligomers represented by the following average unit formula: (R) 2 R 3 2SiO 1 / 2 ) e (R 3 SiO 3 / 2 ) f Among them, component (B) 11 () is better. In this formula, each R 2 Independent alkenyl groups, and examples thereof include groups identical to those described above. Vinyl groups are preferred. In this formula, each R 3 Independently alkyl or aryl. R 3 Examples of alkyl groups include those related to the above-mentioned R. 1 Identical alkyl group. R 3Examples of aryl groups include aryl groups having 6 to 12 carbon atoms, such as phenyl, tolyl, xylyl, and naphthyl. However, at least one R 3 It is an aryl group, typically a phenyl group. In this formula, "m" is an integer from 0 to 10, or an integer from 0 to 5, or an integer from 0 to 3, or an integer of 0 or 1. In this formula, "e" and "f" are numerical values ​​that satisfy the following conditions: e > 0, f > 0, and e + f = 1, or alternatively 0.3 < e and e + f = 1, or alternatively 0.5 < e and e + f = 1. Component (B) 1) Usually, at least one of the organosiloxane oligomers represented by the following formula is selected: (CH 2=CH)(CH 3) 2SiO(C 6H 5) 2SiOSi(CH 3) 2(CH=CH 2) (CH 2=CH)(CH 3) 2SiO(C 6H 5)(CH 3) SiOSi(CH 3) 2(CH=CH 2) (CH 2=CH)(CH 3)(C 6H 5)SiOSi(CH 3)(C 6H 5) 2(CH=CH 2) And component (B) 12 Typically, these are organosiloxane oligomers represented by the following general unit formula: [(CH 2=CH)(CH 3) 2SiO 1 / 2] e [(C 6H 5) SiO 3 / 2 ] f The "e" and "f" are as described above. For component (B) 2) The organosiloxane oligomers are generally selected from at least one of the following: (B) 21 Organosiloxane oligomers represented by the following general formula: HR 3 2SiO(R 3 2SiO) m SiR 3 2H and (B) 22 Organosiloxane oligomers represented by the following average unit formula: (R) 3 2HSiO 1 / 2 ) e (R 3 SiO 3 / 2 ) f Among them, component (B) 21 () is better. In this formula, each R 3 It is an alkyl or aryl group, and examples include groups identical to those described above. However, at least one R 3 It is an aryl group, typically phenyl. In this formula, "m" is an integer from 0 to 10, or an integer from 0 to 5, or an integer from 0 to 3, or an integer of 0 or 1. In this formula, "e" and "f" are numerical values ​​that satisfy the following conditions: e > 0, f > 0, and e + f = 1, or alternatively 0.3 < e and e + f = 1, or alternatively 0.5 < e and e + f = 1. Component (B) 21 It is usually selected from at least one of the organosiloxane oligomers represented by the following formula: H(CH) 3) 2SiO(C 6H 5) 2SiOSi(CH 3) 2H H(CH 3) 2SiO(C 6H 5)(CH 3) SiOSi(CH 3) 2H and component (B) 22 Typically, these are organosiloxane oligomers represented by the following general unit formula: [(CH 3) 2HSiO 1 / 2 ] e [(C 6H 5) SiO 3 / 2 ] f The "e" and "f" are as described above. Component (B) is used in an amount of 1.0 to 55.0% by mass, alternatively in an amount of 1.0 to 50.0% by mass, or alternatively in an amount of 1.0 to 45.0% by mass, each based on the total mass of components (A) to (C). This is because if the amount is equal to or higher than the lower limit of the above range, the composition exhibits good thixotropic properties; however, if the amount is equal to or lower than the upper limit of the above range, the resulting cured product exhibits good transparency. The organosiloxane oligomer used in component (B) may be a component (B) 1) with component (B) 2) A mixture. However, component (B) 1) and component (B) 2) The amount of component (B) is not limited, but the amount of component (B) should be the amount of all silicon atoms bonded to hydrogen atoms relative to all silicon atoms bonded to alkenyl groups in components (A) to (C) in the range of 0.5 to 2.0. Component (C) is any component and is selected from the following organopolysiloxanes: (C) 1) The molecule contains at least one alkenyl group and does not have silicon atoms bonded to aryl groups or SiO2. 4 / 2 Organic polysiloxanes of unit; (C 2) An organopolysiloxane having at least one silicon atom bonded to a hydrogen atom and no silicon atom bonded to an aryl group in the molecule; and component (C 1) with component (C) 2) A mixture of these. If the mixture of components (A) and (B) can be completely cured, component (C) may be added optionally. However, if the mixture cannot be cured due to a lack of silicon-bonded alkenyl groups, component (C) should be added. 1), however, if the mixture cannot solidify due to a lack of silicon atoms bonded to hydrogen atoms, then component (C) should be added. 2). Furthermore, if the cured product obtained by curing this composition is hard, component (C) should be added as a chain extender; however, if the cured product obtained by curing this composition is soft, component (C) should be added as a crosslinking agent. Component (C) 1) The molecule contains at least one alkenyl group and does not have silicon atoms bonded to aryl groups or SiO2. 4 / 2 The unit is an organopolysiloxane. Examples of alkenyl groups include alkenyl groups having 2 to 12 carbon atoms, such as vinyl, allyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, and dodecenyl. Among these, vinyl groups are preferred. Additionally, component (C... Examples of groups bonded to silicon atoms other than alkenyl groups include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tributyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl. Component (C) 1) The molecular structure is not restricted, but typically it is a straight-chain structure, a partially branched straight-chain structure, a branched chain structure, or a cyclic structure. Component (C) 1) It may be a type of organopolysiloxane having such molecular structure, or it may be a mixture of two or more types of organopolysiloxanes having such molecular structure. This component (C) Examples of 1) include dimethyl polysiloxanes with two molecular chain ends capped with dimethyl vinylsiloxy groups, copolymers of dimethyl siloxanes and methyl vinyl siloxanes with two molecular chain ends capped with dimethyl vinylsiloxy groups, copolymers of dimethyl siloxanes and methyl vinyl siloxanes with two molecular chain ends capped with trimethylsiloxy groups, and mixtures of two or more types thereof. Component (C) 2) It is an organopolysiloxane having at least one silicon atom bonded to a hydrogen atom in the molecule and no silicon atom bonded to an aryl group. Component (C 2) Examples of groups bonded to silicon atoms include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tributyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecayl. Component (C) 2) The molecular structure is not restricted, but typically it is a straight-chain structure, a partially branched straight-chain structure, a branched structure, a cyclic structure, or a three-dimensional network structure. Component (C 2) It may be a type of organopolysiloxane having such molecular structure, or it may be a mixture of two or more types of organopolysiloxane having such molecular structure. This component (C) Examples of (2) include methylhydrosiloxanes capped with trimethylsiloxy groups at both ends of the molecular chain, copolymers of dimethylsiloxanes and methylhydrosiloxanes capped with trimethylsiloxy groups at both ends of the molecular chain, dimethylpolysiloxanes capped with dimethylhydrosiloxy groups at both ends of the molecular chain, copolymers of dimethylsiloxanes and methylhydrosiloxanes capped with dimethylhydrosiloxy groups at both ends of the molecular chain, and copolymers of (CH... 3) 2HSiO 1 / 2 Unit and SiO 4 / 2 copolymers composed of unit cells, consisting of (CH 3) 2HSiO 1 / 2 Unit, (CH) 3) 3HSiO 1 / 2 Unit and SiO 4 / 2 Copolymers of unit composition, and mixtures thereof of two or more types. The organopolysiloxane of component (C) may be a component (C) 1) with component (C) 2) The mixture. However, component (C) typically has a viscosity of no more than 1,000 mPa·s at 25°C, alternatively no more than 500 mPa·s, or alternatively no more than 100 mPa·s. Note that in this specification, viscosity is measured using a Type B viscometer according to ASTM D 1084 at 23 ± 2°C. Component (C) is used in an amount of 0 to 55.0% by mass, alternatively in an amount of 0.1 to 50.0% by mass, or alternatively in an amount of 0.5 to 45.0% by mass, each based on the total mass of components (A) to (C). This is because if the amount is equal to or higher than the lower limit of the above range, the composition exhibits good thixotropic properties; however, if the amount is equal to or lower than the upper limit of the above range, the composition exhibits good transparency. The organosiloxane oligomer used in component (C) may be a component (C) 1) with component (C) 2) A mixture. However, component (C) 1) and components (C) 2) The amount of component (C) is not limited, but the amount of component (C) should be the amount of all silicon atoms bonded to hydrogen atoms relative to all silicon atoms bonded to alkenyl groups in components (A) to (C) in the range of 0.5 to 2.0. The molar ratio ("SiH / Vi ratio") of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A) to (C) is in the range of 0.5 to 2.0, alternatively in the range of 0.5 to 1.5, or alternatively in the range of 0.8 to 1.5. This is because if the molar ratio is equal to or higher than the lower limit of the above range, the composition can be completely cured, and the cured product obtained by curing this composition will have appropriate hardness and mechanical strength; however, if the molar ratio is equal to or lower than the upper limit of the above range, the cured product has good thermal stability. Component (D) is a silica filler that imparts thixotropic properties to curable polysiloxane compositions. Component (D) is typically a silica filler that is either atomized or deposited, and its BET surface area is at least 50 m². 2 / g, replacing 80 to 400 m 2 / g, or alternatively 100 to 400 m 2 / g. The surface of the silica filler may be untreated or treated with a treatment agent, such as organochlorosilanes, organoalkoxysilanes, organosilanes, and organosiloxane oligomers. The silica filler used for component (D) is commercially available. Examples of silica fillers include AEROSIL, a brand name purchased from Degussa Corporation. ™ The smog contains silicon dioxide, such as AEROSIL ™ R8200, R9200, R812, R812S, R972, R974, R805, R202; purchased from Cabot Corporation under the trademark CAB-O-SIL. ™ The smog silica from ND-TS, TS610, or TS710; and the trademark REOLOSIL purchased from Tokuyama Corporation. ™ The smog silica, such as DM-10, DM-20S, DM-30, HM-30S, MT-10, PM-20L, QS-10, QS-20A and QS-25C. Based on the total mass of 100 parts by weight of components (A) to (C), the amount of component (D) is in the range of 1 to 10 parts by weight, or alternatively, in the range of 2 to 10 parts by weight. This is because if the amount of component (D) is equal to or higher than the lower limit of the above range, the composition has excellent thixotropic properties and the cured product obtained by curing this composition has appropriate hardness and mechanical strength; however, if the amount is equal to or lower than the upper limit of the above range, the curable polysiloxane composition has good transparency. Component (E) is a hydrosiliconization catalyst used to promote the curing of this composition. Hydrosiliconization catalysts used in component (E) are well known and commercially available in the art. Suitable hydrosiliconization catalysts include, but are not limited to, platinum group metals, including platinum, rhodium, ruthenium, palladium, osmium, or iridium metals or their organometallic compounds, and combinations of any two or more thereof. Component (E) is typically a platinum-based catalyst, which significantly accelerates the curing of this composition. Examples of platinum-based catalysts include platinum powder, chloroplatinic acid, alcoholic solutions of chloroplatinic acid, platinum-alkenylsiloxane complexes, platinum-olefin complexes, and platinum-carbonyl complexes, with platinum-alkenylsiloxane complexes being the most typical. In various embodiments, component (E) is a hydrosiliconization catalyst comprising a complex of platinum and a low molecular weight organopolysiloxane, including a complex of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane and platinum. These complexes can be microencapsulated in a resin matrix. In a specific embodiment, the catalyst comprises a complex of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane and platinum. Examples of suitable silicon hydrocracking catalysts for component (E) are described, for example, in U.S. Patent Nos. 3,159,601, 3,220,972, 3,296,291, 3,419,593, 3,516,946, 3,814,730, 3,989,668, 4,784,879, 5,036,117, and 5,175,325 and EP 0 347 895 B. Microencapsulated silicon hydrocracking catalysts and methods for their preparation are illustrated in U.S. Patent Nos. 4,766,176 and 5,017,654. The amount of component (E) in this composition is an effective amount that promotes the curing of this composition. Specifically, in order to satisfactorily cure this composition, the content of component (E) in terms of mass units is typically about 0.01 to about 500 ppm, or alternatively about 0.01 to about 100 ppm, or alternatively about 0.01 to about 50 ppm, or alternatively about 0.1 to about 10 ppm of the catalytic metal in component (E) relative to this composition. In various embodiments, the curable polysiloxane composition includes (F) a silane hydrocracking reaction inhibitor to adjust the curing rate of the curable polysiloxane composition. In some embodiments, component (F) includes, but is not limited to: alkynyl alcohols (such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, or 2-phenyl-3-butyn-2-ol, 1-ethynyl-cyclohexyl-1-ol); enynyne compounds (such as 3-methyl-3-penten-1-yne, or 3,5-dimethyl-3-hexen-1-yne); or 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, trimethyl[(1,1-dimethyl-2-propynyl)oxy]methylsilane, diallyl maleate, or benzotriazole may be incorporated as optional components into the composition. The amount of component (F) in this composition is not specifically limited, but if included, it is typically in the amount of about 1 to about 10,000 ppm, or alternatively about 10 to about 5,000 ppm, relative to the composition by mass. This is because when the amount of component (F) is greater than or equal to the lower limit of the above range, the composition exhibits good storage stability; however, when the amount of component (F) is less than or equal to the upper limit of the above range, the composition exhibits good curability at low temperatures. To improve the adhesion of the cured product to the substrate material it comes into contact with during curing, this composition may contain an adhesion promoter (G). In some embodiments, the adhesion promoter used for component (G) is typically an organosilicone compound having at least one alkoxy group bonded to a silicon atom in the molecule. Examples of this alkoxy group are methoxy, ethoxy, propoxy, butoxy, and methoxyethoxy; with methoxy being the most typical. Furthermore, examples of non-alkoxy groups bonded to the silicon atoms of this organosilicone compound include substituted or unsubstituted monovalent hydrocarbon groups such as alkyl, alkenyl, aryl, aralkyl, haloalkyl, and the like; epoxy-containing monovalent organic groups such as 3-glycidoxypropyl, 4-glycidoxybutyl, or similar epoxypropoxyalkyl; 2-(3,4-epoxycyclohexyl)ethyl, 3-(3,4-epoxycyclohexyl)propyl, or similar epoxycyclohexylalkyl; and 4-oxiranylbutyl, 8-oxiranyloctyl, or similar epoxyalkylalkyl; acrylic-containing monovalent organic groups such as 3-methacryloxypropyl and the like; and hydrogen atoms. This organosilicone compound typically has silicon-bonded alkenyl or silicon-bonded hydrogen atoms. Furthermore, due to their ability to impart good adhesion to various types of substrate materials, these organosilicone compounds typically possess at least one monovalent organic group containing an epoxy group in their molecule. Examples of this type of organosilane compound are organosilanes, organosiloxane oligomers, and alkyl silicates. Examples of molecular structures of organosiloxane oligomers or alkyl silicates include linear, partially branched, branched, cyclic, and network structures. Linear, branched, and network structures are typical. Examples of this type of organosilicon compound are silane compounds, such as 3-epoxypropoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and the like; siloxane compounds having at least one silyl-bonded alkenyl or silyl-bonded hydrogen atom and at least one silyl-bonded alkoxy group in the molecule; silane compounds having at least one silyl-bonded alkoxy group in the molecule or mixtures of siloxane compounds and siloxane compounds having at least one silyl-bonded hydroxyl group and at least one silyl-bonded alkenyl group in the molecule; and polymethyl silicate, polyethyl silicate, and epoxy-containing polyethyl silicate. In this composition, the amount of component (G) is not specifically limited, but in order to achieve good adhesion to the substrate material in contact during curing, the amount is typically no more than 10 parts by weight of the total mass of 100 parts by weight of components (A) to (C). The refractive index of this composition at 25°C is not limited, but is typically in the range of 1.415 to 1.470. While the viscosity of this composition at 25°C is not limited, it is typically in the range of 10 to 200 Pa·s, as measured at a shear rate of 1 / s. The thixotropic index of this composition is not limited, but is typically in the range of 1.2 to 6.0, alternatively in the range of 1.2 to 5.5, alternatively in the range of 1.5 to 6.0, alternatively in the range of 1.5 to 5.5, alternatively in the range of 2.0 to 6.0, or alternatively in the range of 2.0 to 5.5. This is because if the thixotropic index of this composition is equal to or higher than the lower limit of the above range, the composition will be able to retain its shape after dispensing; however, if the thixotropic index is equal to or lower than the upper limit of the above range, the composition will be able to form a suitable shape, such as a convex lens shape, and upon dispensing. The "thixotropic index" used in this paper is calculated as the viscosity ratio of the composition at 25°C at shear rates of 1 / s and 10 / s, measured using a rheometer with a mandrel (viscosity at 1 / s / viscosity at 10 / s). Example The curable polysiloxane composition of the present invention will be described in detail below using examples and comparative examples. However, the present invention is not limited to the examples described below. [Gel permeation chromatography (GPC)] GPC data for components (a1) and (a2) were collected using a Waters 2695 separation module and a Waters 2414 refractive index detector (RID) from Waters Corporation. Three (7.8 x 300 mm) Styragel HR columns (with molecular weight separation ranges from 100 to 4,000,000) and a Styragel guard column (4.6 x 30 mm) with toluene were used. Samples were prepared as 0.5 wt% toluene solutions and filtered through a 0.45 μm PTFE syringe filter. A flow rate of 1 mL / min was used, with the detector and column temperature at 45°C, an injection volume of 100 μL, and a run time of 60 minutes. The number average molecular weight (Mn) was calculated relative to linear polystyrene standards covering the molecular weight range of 580 to 2,610,000. [Refractive Index] According to standard DIN 51423, the refractive index of curable polysiloxane compositions at 25°C was measured using an Abbe refractometer manufactured by ATAGO Co., Ltd. at an atmospheric pressure of 1013 mbar and a wavelength of 589 nm. [Viscosity] The viscosity of various organosiloxane oligomers and organopolysiloxanes at 25°C was measured using a DV1 VISCOMETER (Brookfield) with a #CP-40Z spindle, and held for 1 minute. [Thixotropic index] The viscosity of the curable polysiloxane composition at 25°C was measured using an ARES G2 rheometer (TA instrument) with a mandrel (part #543661.901, stainless steel, 25 mm, 2°, ETC cone). Viscosities (Pa·s) were measured at shear rates of 1 / s and 10 / s, held for 1 minute. The thixotropic index was calculated from the ratio of the viscosity at 1 / s to the viscosity at 10 / s: [viscosity at 1 / s] / [viscosity at 10 / s]. [Hardness] The curable polysiloxane composition was poured into a mold with a predetermined shaped recess (thickness = 10 mm) and then cured at 150°C for 1 hour. The hardness of the cured product was measured using a Shore A hardness tester specified by ASTM D2240, along with a Type D hardness tester and a Type A hardness tester. [Light transmittance] A curable polysiloxane composition was poured into a mold (thickness = 1 mm) and sandwiched between glass slides (Matsunami Glass Co., Ltd., product #9213). The assembled sample was cured at 190°C for 30 min. The transmittance (%) at wavelengths of 450 nm, 550 nm, and 700 nm was measured at room temperature using the method specified in ASTM D 1003 (UV-Vis spectrometer, Konica Minolta CM-3600A, reference = water). [Examples 1 to 8 and Comparative Examples 1 to 11] The following materials were uniformly mixed in the proportions shown in Tables 1 to 4 to produce a curable polysiloxane composition. When component (A) was solid at 25°C, it was added to the other components using solvents with high viscosity, such as toluene and xylene. Next, to prepare a solvent-free composition, the solvent was evaporated and replaced with other components to promote mixing. For example, first, component (B) was added to a solution of component (A) dissolved in a solvent. Then, the solvent was removed under reduced pressure by heating with nitrogen bubbling. After cooling to room temperature, component (C) was added. The mixture was mixed at room temperature. Additionally, other components were added to the mixture and mixed at room temperature. As mentioned above, the resulting composition and cured product were evaluated. These results are given in Tables 1 to 4. The "SiH / Vi ratio" in each of Tables 1 to 4 indicates the molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded vinyl atoms in components (A) to (C). The following organopolysiloxane is used as component (A). (a1): Organopolysiloxane resin represented by the following average unit formula: [(CH 3) 3SiO 1 / 2 ] 0.40 [(CH 2=CH)(CH 3) 2SiO 1 / 2 ] 0.04 (SiO 4 / 2 ) 0.56 It has a vinyl content of about 1.9% by mass and a number average molecular weight (Mn) of about 5,000, and is a solid at 25°C. (a2): Organopolysiloxane resin represented by the following average unit formula: [(CH 3) 3SiO 1 / 2 ] 0.40 [(CH 2=CH)(CH 3) 2SiO 1 / 2 ] 0.10 (SiO 4 / 2 ) 0.50 It has a vinyl content of about 3.0% by mass and a number average molecular weight (Mn) of about 3,000, and is a solid at 25°C. The following organopolysiloxane resins are used as comparisons for component (A). (a3): Organopolysiloxane resins represented by the following average unit formula: [(CH 2=CH)(CH 3) 2SiO 1 / 2 ] 0.25 (C 6H 5SiO 3 / 2 ) 0.75It has a vinyl content of 5.62% by mass and is a solid at 25°C. (a4): Organopolysiloxane resin represented by the following average unit formula: [(CH 3) 3SiO 1 / 2 ] 0.14 [(CH 2=CH)(CH 3) 2SiO 1 / 2 ] 0.11 (CH 3SiO 3 / 2 ) 0.53 (C 6H 5SiO 3 / 2 ) 0.22 It has a vinyl content of about 2.2% by mass and is a solid at 25°C. The following organosiloxane oligomers are used as component (B). (b1): Organosiloxane oligomers represented by the following formula: (CH 2=CH)(CH 3) 2SiO(C 6H 5) 2SiOSi(CH 3) 2(CH=CH 2) It has a viscosity of 8.7 mPa·s and a vinyl content of approximately 14.06% by mass. (b2): Organosiloxane oligomers represented by the following formula: H(CH 3) 2SiO(C 6H 5) 2SiOSi(CH 3) 2H and it has a viscosity of 4.4 mPa·s and a silicon atom bonded hydrogen atom content of about 0.61% by mass. (b3): ​​Organosiloxane oligomers represented by the following average unit formula: [(CH 3) 2HSiO 1 / 2 ] 0.60 (C 6H 5SiO 3 / 2 ) 0.40 It has a viscosity of 29 mPa·s and a silicon atom bond hydrogen atom content of about 0.65% by mass. The following organopolysiloxanes are used as components (B) for comparison. (b4): Organopolysiloxanes represented by the following formula: (CH 2=CH)(CH 3) 2SiO[(C 6H 5)(CH 3)SiO] 20 Si(CH 3) 2(CH=CH 2) It has a viscosity of 2,300 mPa·s and a vinyl content of approximately 1.43% by mass. (b5): Organopolysiloxane represented by the following formula: (CH 2=CH)(CH 3) 2SiO[(CH 3) 2SiO] 200 [(C 6H 5) 2SiO] 50 Si(CH 3) 2(CH=CH 2) It has a viscosity of 14,000 mPa·s and a vinyl content of about 0.22% by mass. The following organopolysiloxanes are used as component (C). (c1): Organopolysiloxanes represented by the following formula: (CH 2=CH)(CH 3) 2SiO[(CH 3) 2SiO] 7Si(CH 3) 2(CH=CH 2) It has a viscosity of 7 mPa·s and a vinyl content of approximately 7.49% by mass. (c2): Organopolysiloxane represented by the following formula: (CH 2=CH)(CH 3) 2SiO[(CH 3) 2SiO] 45 Si(CH 3) 2(CH=CH 2) It has a viscosity of 60 mPa·s and a vinyl content of approximately 1.66% by mass. (c3): Organopolysiloxane represented by the following formula: H(CH 3) 2SiO[(CH 3) 2SiO] 16 Si(CH 3) 2H and it has a viscosity of 15 mPa·s and a silicon atom bonded hydrogen atom content of about 0.15% by mass. (c4): Organopolysiloxane resin represented by the following average unit formula: [(CH 3) 2HSiO 1 / 2 ] 0.65 (SiO 4 / 2 ) 0.35 It has a viscosity of 23 mPa·s and a silicon atom bond hydrogen atom content of about 0.96% by mass. The following smog uses silicon dioxide as component (D). (d1): BET specific surface area is 230 m². 2 / g of smog silica (from TOKUYAMA Corporation's REOLOSIL DM-30S) The following hydrosiliconization catalyst is used as component (E). (e1): A solution of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane containing a platinum complex with 1,3-divinyl-1,1,3,3-tetramethyldisiloxane (platinum content = 4% by mass). The following silaneation inhibitors are used as component (F): (f1): 1-ethynyl-cyclohexyl-1-ol (f2): 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane The following tackifiers are used as component (G). (g1): 1,6-bis(trimethoxysilyl)hexane (g2): an organopolysiloxane resin represented by the following average unit formula: [(CH 2=CH)(CH 3) 2SiO 1 / 2 ] 0.18 (C 6H 5SiO 3 / 2 ) 0.54 [CH 2(O)CHCH 2O(CH 2) 3SiO 3 / 2 ] 0.28 [Table 1] [Table 2] [Table 3] [Table 4] Examples IE1 to IE8 are representative examples of the curable polysiloxane compositions described herein, exhibiting thixotropic properties (thixotropic index ≥ 1.5) with transparency (transmittance > 99% at 450 nm). As shown in Comparative Example CE2, thixotropic properties cannot be achieved without component (D). Meanwhile, Comparative Examples CE3 and CE4 show lower optical properties at 450 nm, 96.39% and 96.86%, respectively. When comparing Comparative Example CE4 with Examples IE5 to IE8, the use of component (B) is considered to impart transparency and exhibit thixotropic properties. According to Comparative Example CE5, since comparative component (b4) is incompatible with components (A) and (C), a heterogeneous turbid liquid is obtained. Comparative Examples CE6 to CE9 demonstrate curable polysiloxane compositions using comparative components (comparative components a3, a4) and comparative components (comparative components b4, b5), which exhibit a low optical transmittance of less than 99% at 450 nm. In the case of Comparative Example CE1, when 65.06% by mass of component (a1) was used, an excessively viscous liquid was obtained. Industrial Applicability Although the curable polysiloxane composition of this invention contains a large amount of organopolysiloxane resin, it has excellent thixotropic properties and can be cured to form a transparent cured product. Therefore, the curable polysiloxane composition can be used as a sealant, adhesive, or coating for optical semiconductor components in electrical / electronic equipment. none none

Claims

1. A curable polysiloxane composition comprising: (A) an organopolysiloxane resin represented by the following average unit formula: (R13SiO1 / 2)a(R2R12SiO1 / 2)b(SiO4 / 2)c(H2O1 / 2)d wherein each R1 is independently an alkyl group; R2 is an alkenyl group; and "a", "b", "c", and "d" are values ​​satisfying the following conditions: a ≥ 0, b > 0, 0.3 ≤ c ≤ 0.7, 0 ≤ d ≤ 0.05, and a + b + c = 1; (B) an organosiloxane oligomer with a viscosity of not more than 1,000 mPa·s at 25°C and comprising: (B1) an organosiloxane oligomer having at least one silicon atom bonded to an alkenyl group and at least one silicon atom bonded to an aryl group in the molecule; (C) The following organopolysiloxanes are selected: (C1) an organopolysiloxane having at least one alkenyl group in the molecule and not having silicon atoms bonded to aryl groups and SiO4 / 2 units; (C2) an organopolysiloxane having at least one silicon atom bonded to a hydrogen atom in the molecule and not having silicon atoms bonded to aryl groups; and a mixture of components (C1) and (C2); (D) a silica filler; and (E) a catalytic amount of a hydrosilylation catalyst. The amount of component (A) is in the range of 40.0 to 65.0% by mass, the amount of component (B) is in the range of 1.0 to 55.0% by mass, and the amount of component (C) is in the range of 0 to 50.0% by mass, each based on the total mass of components (A) to (C), and the amount of component (D) is in the range of 1 to 10 parts by mass relative to 100 parts by mass of the total mass of components (A) to (C), subject to the limitation that the molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A) to (C) is in the range of 0.5 to 2.0, wherein component (B1) is selected from at least one of the following: (B11) an organosilicon oligomer represented by the following general formula: R2R32SiO(R32SiO)mSiR32R2 Each R2 is independently alkenyl; each R3 is independently alkyl or aryl, with the restriction that at least one R3 is aryl; and "m" is 1, and (B12) is an organosiloxane oligomer represented by the following average unit formula: [(CH2=CH)(CH3)2SiO1 / 2]e[(C6H5)SiO3 / 2]f where "e" and "f" are values ​​that satisfy the following conditions: e > 0, f > 0, and e + f = 1.

2. The curable polysiloxane composition as claimed in claim 1, wherein component (B11) is selected from at least one of the organosilicon oligomers represented by the following formula: (CH2=CH)(CH3)2SiO(C6H5)2SiOSi(CH3)2(CH=CH2) (CH2=CH)(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2(CH=CH2) (CH2=CH)(CH3)(C6H5)SiOSi(CH3)(C6H5)(CH=CH2).

3. The curable polysiloxane composition of claim 1, wherein component (B) further comprises (B2) an organosiloxane oligomer having at least one silicon atom bonded to a hydrogen atom and at least one silicon atom bonded to an aryl group in the molecule.

4. The curable polysiloxane composition of claim 3, wherein component (B2) is selected from at least one of the following: (B21) an organosiloxane oligomer represented by the following general formula: HR32SiO(R32SiO)mSiR32H, wherein each R3 is independently alkyl or aryl, with the limitation that at least one R3 is aryl; and "m" is an integer from 0 to 10, and (B22) an organosiloxane oligomer represented by the following average unit formula: (R32HSiO1 / 2)e(R3SiO3 / 2)f, wherein R3 is as described above; and "e" and "f" are values ​​satisfying the following conditions: e > 0, f > 0, and e + f = 1.

5. The curable polysiloxane composition of claim 4, wherein component (B21) is selected from at least one of the organosiloxane oligomers represented by the following formulas: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H H(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2H and component (B22) is an organosiloxane oligomer represented by the following general unit formula: [(CH3)2HSiO1 / 2]e[(C6H5)SiO3 / 2]f where "e" and "f" are as described above.

6. The curable polysiloxane composition of any one of claims 1 to 5 further comprises: (F) a silicon hydrogenation reaction inhibitor, in an amount of 0.1 to 10,000 ppm relative to the composition by mass.

7. The curable polysiloxane composition of any one of claims 1 to 5 further comprises: (G) an adhesive, the amount of which is at most 10 parts by weight relative to the total mass of 100 parts by weight of components (A) to (C).