Curable silicone composition

Abstract

The present disclosure relates to an organopolysiloxane resin having (A) an alkenyl group in the molecule, (B) an organosiloxane oligomer having a viscosity of 1,000 mPa s or less at 25°C, and having at least one silicon-bonded alkenyl group or silicon-bonded hydrogen atom and at least one silicon-bonded aryl group in the molecule, and (C) an organosiloxane oligomer having at least one alkenyl group in the molecule, and having at least one silicon-bonded aryl group and SiO 4 / 2 The present invention relates to a curable silicone composition comprising an organopolysiloxane having no silicon-bonded aryl groups or an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and no silicon-bonded aryl groups, (D) a silica filler, and (E) a hydrosilylation reaction catalyst. Despite containing a large amount of organopolysiloxane resin, this composition has excellent thixotropic properties and can be cured to form a transparent cured product.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and all benefits of U.S. Provisional Patent Application No. 63 / 313,396, filed February 24, 2022, the contents of which are incorporated herein by reference.

[0002] The present invention relates to a curable silicone composition. [Background technology]

[0003] (CH3)3SiO 1 / 2 The unit, CH2=CH(CH3)SiO 2 / 2 Unit and SiO 4 / 2 A curable silicone composition comprising an organopolysiloxane resin consisting of a unit, an organopolysiloxane having at least two silicon-bonded hydrogen atoms in the molecule, and a hydrosilylation reaction catalyst is cured to form a transparent cured product having excellent heat resistance, electrical insulation properties, and weather resistance.Therefore, the curable silicone composition is widely used as a protective coating agent, encapsulant, or sealant for electrical / electronic devices.In certain applications, the thixotropic properties of the curable silicone composition are required to control the flowability and retain the shape of the curable silicone composition after it is dispensed.

[0004] For example, in Example 1 of Patent Document 1, CH2=CH(CH3)2SiO 1 / 2 The unit, (CH3)3SiO 1 / 2 Unit and SiO 4 / 2 Patent Document 1 discloses a curable silicone composition that includes an organopolysiloxane resin consisting of a unit, a vinyl-terminated dimethylpolysiloxane, a methylhydrogenpolysiloxane, and a platinum catalyst. Patent Document 1 also discloses an inorganic filler such as fumed silica for improving strength within a range that does not impair transparency. However, Patent Document 1 does not mention improving the thixotropic properties of the curable silicone composition.

[0005] In Example 4 of Patent Document 2, a copolymer of dimethylsiloxane and methylvinylsiloxane, CH2=CH(CH3)2SiO, in which both ends of the molecular chain are capped with dimethylvinylsiloxy groups, is described. 1 / 2 The unit, (CH3)3SiO 1 / 2 Unit and SiO 4 / 2 Organopolysiloxane resin consisting of the unit, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 Patent Document 2 discloses a curable silicone composition containing a methylhydrogenpolysiloxane consisting of units, a platinum catalyst, and fumed silica. However, when this curable silicone composition is cured, it forms a cured product with low transparency. In addition, in Example 5 of Patent Document 2, a copolymer of dimethylsiloxane and diphenylsiloxane, CH2=CH(CH3)2SiO, in which both ends of the molecular chain are capped with dimethylvinylsiloxy groups, is disclosed. 1 / 2 The unit, (CH3)3SiO 1 / 2 Unit and SiO 4 / 2 Organopolysiloxane resin consisting of the unit, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 It discloses a curable silicone composition containing a methylhydrogenpolysiloxane consisting of units and a platinum catalyst. However, Patent Document 2 does not mention enhancing the thixotropic properties of the curable silicone composition.

[0006] In Example 1 of Patent Document 3, a copolymer of dimethylsiloxane and diphenylsiloxane, CH2=CH(CH3)2SiO, in which both ends of the molecular chain are capped with trivinylsiloxy groups, is described. 1 / 2 The unit, (CH3)3SiO 1 / 2 Unit and SiO 4 / 2 Organopolysiloxane resin consisting of the unit, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2The paper discloses a curable silicone composition containing a polymethylhydrogensiloxane consisting of units, a methylhydrogenpolysiloxane in which both ends of the molecular chain are capped with trimethylsiloxy groups, a platinum catalyst, fumed silica, and an organopolysiloxane having glycidoxypropyl groups as a thixotropy-imparting agent. This curable silicone composition cures to form a transparent cured product, but its thixotropy properties are inferior to those of a composition using a dimethylpolysiloxane in which both ends of the molecular chain are capped with dimethylvinylsiloxy groups instead of a copolymer of dimethylsiloxane and diphenylsiloxane.

[0007] In several examples, Patent Document 4 describes a copolymer of dimethylsiloxane and diphenylsiloxane, in which both ends of the molecular chain are capped with dimethylvinylsiloxy groups, (CH3)3SiO 1 / 2 The unit, CH2=CH(CH3)SiO 2 / 2 Unit and SiO 4 / 2 Organopolysiloxane resin consisting of the unit, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2 The present publication discloses a curable silicone composition comprising an organohydrogenpolysiloxane consisting of R2SiO units, or a copolymer of methylhydrogensiloxane and dimethylsiloxane, both ends of which are capped with trimethylsiloxy groups, a platinum catalyst, and fumed silica. These curable silicone compositions have thixotropic properties and cure to form a transparent cured product. However, when the organopolysiloxane resin is R2SiO 2 / 2 It is necessary to contain a unit (wherein each R independently represents an alkenyl group or an alkyl group which may be substituted with a halogen). Furthermore, the amount of the organopolysiloxane resin is limited to the range of 10 to 40 mass % based on the total amount of the linear organopolysiloxane and the organopolysiloxane resin.

[0008] Prior art documents Patent Literature Patent Document 1: U.S. Patent Application Publication No. 2004 / 0116640(A1) Patent Document 2: JP 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) Summary of the Invention

[0009] Problem to be solved by the invention An object of the present invention is to provide a curable silicone composition that, despite containing a large amount of organopolysiloxane resin, has excellent thixotropic properties and is capable of curing to form a transparent cured product.

[0010] Means for solving the problem The curable silicone composition of the present invention comprises: (A) The 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 the formula, each R 1 are independently alkyl groups, R 2 is an alkenyl group, and "a", "b", "c" and "d" are numbers that satisfy the conditions: a≧0, b>0, 0.3≦c≦0.7, 0≦d≦0.05, and a+b+c=1; and (B) an organosiloxane oligomer having a viscosity at 25°C of 1,000 mPa s or less, selected from (B1) an organosiloxane oligomer having at least one silicon-bonded alkenyl group and at least one silicon-bonded aryl group in the molecule, (B2) an organosiloxane oligomer having at least one silicon-bonded hydrogen atom and at least one silicon-bonded aryl group in the molecule, and a mixture of components (B1) and (B2); (C) (C1) has at least one alkenyl group in the molecule, and has a silicon-bonded aryl group and SiO 4 / 2 an organopolysiloxane selected from the group consisting of organopolysiloxanes having no silicon-bonded aryl groups, (C2) organopolysiloxanes having at least one silicon-bonded hydrogen atom in the molecule and no silicon-bonded aryl groups, and a mixture of components (C1) and (C2); (D) a silica filler; and (E) a catalytic amount of a hydrosilylation reaction catalyst; Here, based on the total mass of components (A) to (C), the amount of component (A) is in the range of 40.0 to 65.0 mass%, the amount of component (B) is in the range of 1.0 to 55.0 mass%, the amount of component (C) is in the range of 0 to 50.0 mass%, and the amount of component (D) is in the range of 1 to 10 parts by mass per 100 parts by mass of the total mass of components (A) to (C), with the proviso 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.

[0011] In various embodiments, component (B1) is 11 ) the following general formula: R 2 R 3 2SiO(R 3 2SiO) m SiR 3 2R 2 (In the formula, each R 2 are independently an alkenyl group, and each R 3 are independently an alkyl group or an aryl group, provided that at least one R 3 is an aryl group, and "m" is an integer of 0 to 10), and (B 12 )Average unit formula below: (R 2 R 3 2SiO 1 / 2 ) e (R 3 SiO 3 / 2 ) f (In the formula, R 2and R 3 is as defined above, and “e” and “f” are numbers satisfying the conditions e>0, f>0, and e+f=1.

[0012] In various embodiments, component (B 11 ) is expressed 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) and component (B) is at least one selected from organosiloxane oligomers represented by the formula: 12 ) has the following general unit formula: [(CH2=CH)(CH3)2SiO 1 / 2 ] e [(C6H5)SiO 3 / 2 ] f (wherein "e" and "f" are as defined above) is an organosiloxane oligomer.

[0013] In various embodiments, component (B2) is 21 ) the following general formula: HR 3 2SiO(R 3 2SiO) m SiR 3 2H (In the formula, each R 3 are independently an alkyl group or an aryl group, provided that at least one R 3 is an aryl group, and "m" is an integer of 0 to 10), and (B 22 )Average unit formula below: (R 3 2HSiO 1 / 2 ) e (R 3 SiO3 / 2 ) f (In the formula, R 3 is as defined above, and “e” and “f” are numbers satisfying the conditions e>0, f>0, and e+f=1.

[0014] In various embodiments, component (B 21 ) is expressed by the following formula: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H H(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2H and component (B) is at least one selected from organosiloxane oligomers represented by the formula: 22 ) has the following general unit formula: [(CH3)2HSiO 1 / 2 ] e [(C6H5)SiO 3 / 2 )] f (wherein "e" and "f" are as defined above) is an organosiloxane oligomer.

[0015] In various embodiments, the curable silicone composition further comprises a hydrosilylation reaction inhibitor in an amount, calculated in units of mass for the (F) composition, of 0.1 to 10,000 ppm of this component.

[0016] In various embodiments, the curable silicone composition further comprises (G) an adhesion promoter in an amount of up to 10 parts by weight per 100 parts by weight of the combined weight of components (A)-(C).

[0017] Effect of the Invention Although the curable silicone composition of the present invention contains a large amount of organopolysiloxane resin, it has excellent thixotropic properties and is capable of curing to form a transparent cured product.

[0018] definition The terms "comprising" or "comprise" are used herein in their broadest sense to mean and encompass the ideas of "including," "include," "consist(ing) essentially of," and "consist(ing) of." The use of "for example," "eg," "such as," and "including" to list examples does not limit the examples listed. Thus, "for example" or "such as" means "for example, but not limited to" or "such as, but not limited to," and encompasses other similar or equivalent examples. As used herein, the term "about" serves to reasonably encompass or describe slight variations in values ​​measured by instrumental analysis or as a result of handling samples. Such slight variations may be as much as ±0-25, ±0-10, ±0-5, or ±0-2.5% of the numerical value. Furthermore, the term "about" applies to both numerical values ​​when relating to a range of values. Furthermore, the term "about" may be applied to numerical values ​​even if not expressly stated.

[0019] It is to be understood that the appended claims are not limited to the express and specific compounds, compositions, or methods described in the Detailed Description, which may vary among specific embodiments within the scope of the appended claims. With respect to any Markush group on which the description of specific features or aspects of various embodiments is relied upon herein, it is to be understood that different, special, and / or unexpected results may be obtained from each element of the respective Markush group, independently of all other Markush elements. Each element of the Markush group may be relied upon individually and / or in combination to provide sufficient support for specific embodiments within the scope of the appended claims.

[0020] Any ranges and subranges relied upon in describing various embodiments of the present invention should also be understood to be within the scope of the appended claims, both individually and inclusively, and all ranges including integer and / or fractional values ​​are understood to be described and contemplated therein, even if not expressly written herein. Those skilled in the art will readily recognize that the recited ranges and subranges fully describe and enable various embodiments of the present invention, and that such ranges and subranges may be further described into relevant halves, thirds, fourths, fifths, etc. As merely an example, a range "from 0.1 to 0.9" may be further described into a lower third, i.e., 0.1 to 0.3, a middle third, i.e., 0.4 to 0.6, and an upper third, i.e., 0.7 to 0.9, which are individually and inclusively within the scope of the appended claims, and may be relied upon and provide sufficient support for specific embodiments within the scope of the appended claims, individually and / or inclusively. In addition, with respect to words defining or modifying a range, such as "at least," "greater than," "less than," "less than," etc., such words should be understood to include subranges and / or upper or lower limits. As another example, the range "at least 10" essentially includes subranges of at least 10 to 35, at least 10 to 25, 25 to 35, etc., each of which may be relied upon individually and / or inclusively to provide sufficient support for specific embodiments within the scope of the appended claims. Finally, individual numbers within the disclosed ranges may be relied upon to provide sufficient support for specific embodiments within the scope of the appended claims. For example, the range "from 1 to 9" includes various individual integers, such as 3, and individual numbers including decimal points (or fractions), such as 4.1, which may be relied upon to provide sufficient support for specific embodiments within the scope of the appended claims. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The curable silicone composition of the present invention will now be described in detail.

[0022] Component (A) has 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 The organopolysiloxane resin is represented by the formula:

[0023] In the formula, each R 1 are independently an alkyl group. The alkyl group is exemplified by an alkyl group having 1 to 12 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, a neopentyl group, a hexyl group, a cyclohexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a undecyl group, and a dodecyl group. Among these, a methyl group is preferred.

[0024] In the formula, R 2 is an alkenyl group. The alkenyl group is exemplified by alkenyl groups having 2 to 12 carbon atoms, such as a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group, an octenyl group, a nonenyl group, a decenyl group, an undecenyl group, and a dodecenyl group. Among these, a vinyl group is preferred.

[0025] In the formula, "a", "b", "c" and "d" are numbers that satisfy the conditions of a≧0, b>0, 0.3≦c≦0.7, 0≦d≦0.05, and a+b+c=1, and may be 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 may be 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, when "a", "b", "c" and "d" are numbers within the above-mentioned ranges, the cured product obtained by curing the present composition has appropriate hardness and mechanical strength.

[0026] The molecular weight of the organopolysiloxane resin of component (A) is not limited, but its number average molecular weight (Mn), measured by gel permeation chromatography (GPC) in terms of 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 more than 6,000 g / mol, alternatively not more than 5,500 g / mol. The Mn of component (A) can be any range combining the upper and lower limits described above. It should be noted that when component (A) is in a solid state at 25°C and it is difficult to uniformly mix other components in the composition, this problem can be solved by preparing an organic solution of component (A) in advance, mixing it with some or all of components (B) and (C), and then removing the organic solvent used from this mixture. It should be noted that any organic solvent that can be used to prepare the organic solution of component (A) can be used as long as it can dissolve component (A) and can be easily removed. Specific examples include, but are not limited to, aromatic hydrocarbons such as toluene and xylene, and aliphatic hydrocarbons such as hexane and heptane.

[0027] Component (A) is used in an amount of 40.0 to 65.0% by weight, alternatively 40.0 to 62.0% by weight, alternatively 45.0 to 65.0% by weight, or alternatively 45.0 to 62.0% by weight, based on the total weight of components (A) to (C). This is because, when the amount is equal to or greater than the lower limit of the above range, the cured product obtained by curing the composition has appropriate hardness and mechanical strength, whereas, when the amount is equal to or less than the upper limit of the above range, the composition has a suitable viscosity at 25°C.

[0028] Component (B) is an organosiloxane oligomer for imparting thixotropic properties to the curable silicone composition and for imparting transparency to the cured product obtained by curing the composition. The molecular structure of the organosiloxane oligomer of component (B) is not limited, but is exemplified by linear, partially branched linear, and branched. The molecular weight of the organosiloxane oligomer of component (B) is not limited, but is preferably 2,000 g / mol or less, alternatively 1,500 g / mol or less. Such organosiloxane oligomers typically have a viscosity at 25°C of 1,000 mPa·s or less, alternatively 500 mPa·s or less, or alternatively 100 mPa·s or less. It should be noted that in this specification, viscosity is measured at 23±2°C using a Brookfield viscometer according to ASTM D1084.

[0029] The organosiloxane oligomer of component (B) also acts as a chain extender or crosslinker for the composition and is selected from (B1) an organosiloxane oligomer having at least one silicon-bonded alkenyl group and at least one silicon-bonded aryl group in the molecule, (B2) an organosiloxane oligomer having at least one silicon-bonded hydrogen atom and at least one silicon-bonded aryl group in the molecule, and a mixture of components (B1) and (B2).

[0030] The organosiloxane oligomer of component (B1) is typically 11 ) the following general formula: R 2 R 3 2SiO(R 3 2SiO) m SiR 3 2R 2 Organosiloxane oligomers represented by the formula (B 12 )Average unit formula below: (R 2 R 3 2SiO 1 / 2 ) e (R 3 SiO 3 / 2 ) f It is at least one selected from organosiloxane oligomers represented by Among these, component (B 11 ) is preferred.

[0031] In the formula, each R 2 is independently an alkenyl group, and examples thereof include the same groups as those described above. Among these, a vinyl group is preferred.

[0032] In the formula, each R 3 is independently an alkyl group or an aryl group. Examples of the alkyl group of R 3 include the same alkyl groups as R 1 described above. Examples of the aryl group of R 3 include aryl groups having 6 to 12 carbon atoms such as a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. However, at least one R 3 is an aryl group, typically a phenyl group.

[0033] In the formula, "m" is an integer from 0 to 10, alternatively an integer from 0 to 5, alternatively an integer from 0 to 3, or alternatively an integer of 0 or 1.

[0034] In the formula, "e" and "f" are numbers that satisfy the conditions of e > 0, f > 0, and e + f = 1, alternatively 0.3 < e and e + f = 1, or alternatively 0.5 < e and e + f = 1.

[0035] Component (B1) is typically 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)2(CH=CH2) It is at least one selected from organosiloxane oligomers represented by 12) is typically the following general unit formula: [(CH2=CH)(CH3)2SiO 1 / 2 e [(C6H5)SiO 3 / 2 f (wherein, "e" and "f" are as defined above) and is an organosiloxane oligomer represented by.

[0036] The organosiloxane oligomer of component (B2) is typically (B 21 ) the following general formula: HR 3 2SiO(R 3 2SiO) m SiR 3 2H and an organosiloxane oligomer represented by, and (B 22 ) the following average unit formula: (R 3 2HSiO 1 / 2 ) e (R 3 SiO 3 / 2 ) f and is at least one selected from organosiloxane oligomers represented by. Among these, component (B 21 ) is preferred.

[0037] In the formula, each R 3 is an alkyl group or an aryl group, and examples thereof are the same groups as those described above. However, at least one R 3 is an aryl group, typically a phenyl group.

[0038] In the formula, "m" is an integer from 0 to 10, alternatively an integer from 0 to 5, alternatively an integer from 0 to 3, or alternatively an integer of 0 or 1.

[0039] In the formula, "e" and f "are", e > 0, f > 0, and e + f = 1, alternatively 0.3 < e and e + f = 1, or alternatively 0.5 < e and e + f = 1. ​​

[0040] Ingredients (B 21 ) is typically represented by the following formula: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H H(CH3)2SiO(C6H5)(CH3)SiOSi(CH3)2H and component (B) is at least one selected from organosiloxane oligomers represented by the formula: 22 ) typically has the following general unit formula: [(CH3)2HSiO 1 / 2 ] e [(C6H5)SiO 3 / 2 )] f (wherein "e" and "f" are as defined above) is an organosiloxane oligomer.

[0041] Component (B) is used in an amount of 1.0 to 55.0% by weight, alternatively 1.0 to 50.0% by weight, or alternatively 1.0 to 45.0% by weight, based on the total weight of components (A) to (C). This is because, if the amount is equal to or greater than the lower limit of the above range, the composition has good thixotropic properties, while if the amount is equal to or less than the upper limit of the above range, the resulting cured product has good transparency. The organosiloxane oligomer of component (B) may be a mixture of components (B1) and (B2). However, the amounts of components (B1) and (B2) are not limited, but the amount of component (B) should be such 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.

[0042] Component (C) is an optional component, which has at least one alkenyl group in the (C1) molecule, and has silicon-bonded aryl groups and SiO 4 / 2 The organopolysiloxane is selected from organopolysiloxanes having no silicon-bonded aryl groups, organopolysiloxanes having at least one silicon-bonded hydrogen atom in the (C2) molecule and no silicon-bonded aryl groups, and a mixture of components (C1) and (C2).

[0043] If the mixture of components (A) and (B) can be completely cured, the addition of component (C) is optional. However, if the mixture cannot be cured due to a lack of silicon-bonded alkenyl groups, component (C1) should be added, and if the mixture cannot be cured due to a lack of silicon-bonded hydrogen atoms, component (C2) should be added. Furthermore, if the cured product obtained by curing the composition is hard, component (C) should be added as a chain extender, and if the cured product obtained by curing the composition is soft, component (C) should be added as a crosslinker.

[0044] Component (C1) has at least one alkenyl group in the molecule, and has silicon-bonded aryl groups and SiO 4 / 2 It is an organopolysiloxane having no unit. Examples of the alkenyl group 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 is preferred. Examples of groups bonded to silicon atoms other than alkenyl groups in component (C1) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl.

[0045] The molecular structure of component (C1) is not limited, but is typically a linear structure, a partially branched linear structure, a branched structure, or a cyclic structure. Component (C1) may be one organopolysiloxane having these molecular structures, or may be a mixture of two or more organopolysiloxanes having these molecular structures.

[0046] Examples of such component (C1) include dimethylpolysiloxanes whose molecular chain ends are capped with dimethylvinylsiloxy groups, copolymers of dimethylsiloxanes whose molecular chain ends are capped with dimethylvinylsiloxy groups and methylvinylsiloxanes, copolymers of dimethylsiloxanes whose molecular chain ends are capped with trimethylsiloxy groups and methylvinylsiloxanes, and mixtures of two or more of these.

[0047] Component (C2) is an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and no silicon-bonded aryl group. Examples of the group bonded to the silicon atom in component (C2) include alkyl groups having 1 to 12 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, neopentyl, hexyl, cyclohexyl, heptyl, octyl, nonyl, decyl, undecyl, and dodecyl groups.

[0048] The molecular structure of component (C2) is not limited, but typically includes a linear structure, a partially branched linear structure, a branched structure, a cyclic structure, and a three-dimensional network structure. Component (C2) may be one organopolysiloxane having these molecular structures, or may be a mixture of two or more organopolysiloxanes having these molecular structures.

[0049] Examples of such component (C2) include methylhydrogenpolysiloxane capped at both molecular chain ends with trimethylsiloxy groups, a copolymer of dimethylsiloxane and methylhydrogensiloxane capped at both molecular chain ends with trimethylsiloxy groups, dimethylpolysiloxane capped at both molecular chain ends with dimethylhydrogensiloxy groups, a copolymer of dimethylsiloxane and methylhydrogensiloxane capped at both molecular chain ends with dimethylhydrogensiloxy groups, (CH3)2HSiO 1 / 2 Unit and SiO 4 / 2A copolymer consisting of the unit (CH3)2HSiO 1 / 2 The unit, (CH3)3HSiO 1 / 2 Unit and SiO 4 / 2 Copolymers of these units, as well as mixtures of two or more of these, are included.

[0050] The organopolysiloxane of component (C) may be a mixture of components (C1) and (C2). However, component (C) typically has a viscosity of 1,000 mPa·s or less, alternatively 500 mPa·s or less, or alternatively 100 mPa·s or less at 25° C. It should be noted that viscosity herein is measured at 23±2° C. using a Brookfield viscometer according to ASTM D1084.

[0051] Component (C) is used in an amount of 0 to 55.0% by weight, alternatively 0.1 to 50.0% by weight, or alternatively 0.5 to 45.0% by weight, based on the total weight of components (A) to (C). This is because when the amount is equal to or greater than the lower limit of the range, the composition has good thixotropic properties, while when the amount is equal to or less than the upper limit of the range, the composition has good transparency. The organosiloxane oligomer of component (C) may be a mixture of components (C1) and (C2). However, the amounts of components (C1) and (C2) are not limited, but the amount of component (C) should be such 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.

[0052] The molar ratio of all silicon-bonded hydrogen atoms to all silicon-bonded alkenyl groups in components (A) to (C) ("SiH / Vi ratio") 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, when the molar ratio is equal to or greater than the lower limit of the above range, the composition can be completely cured, and the cured product obtained by curing the composition has appropriate hardness and mechanical strength, whereas, when the molar ratio is equal to or less than the upper limit of the above range, the cured product has good thermal stability.

[0053] Component (D) is a silica filler for imparting thixotropic properties to the curable silicone composition. Component (D) is typically at least 50 ml 2 / g, alternatively 80-400m 2 / g, or alternatively 100-400m 2 The silica filler is a fumed or precipitated silica filler having a BET surface area of ​​1000 nm / g. The surface of the silica filler may be untreated or may be treated with a treating agent such as organochlorosilanes, organoalkoxysilanes, organosilazanes, and organosiloxane oligomers.

[0054] The silica fillers of component (D) are commercially available. Examples of silica fillers include fumed silicas manufactured by Degussa under the trade name AEROSIL®, such as AEROSIL® R8200, R9200, R812, R812S, R972, R974, R805, R202, fumed silicas manufactured by Cabot under the trade name CAB-O-SIL® ND-TS, TS610 or TS710, and fumed silicas manufactured by Tokuyama under the trade name REOLOSIL®, such as DM-10, DM-20S, DM-30, HM-30S, MT-10, PM-20L, QS-10, QS-20A, and QS-25C.

[0055] The amount of component (D) is in the range of 1 to 10 parts by mass, alternatively in the range of 2 to 10 parts by mass, based on 100 parts by mass of the combined total of components (A) to (C).This is because, when the amount of component (D) is at or above the lower limit of the above range, the composition has excellent thixotropic properties, and the cured product obtained by curing the composition has appropriate hardness and mechanical strength, whereas, when the amount is at or below the upper limit of the above range, the curable silicone composition has good transparency.

[0056] Component (E) is a hydrosilylation catalyst used to accelerate the curing of the composition. Component (E) hydrosilylation catalysts are well known in the art and commercially available. Suitable hydrosilylation catalysts include, but are not limited to, platinum group metals, including platinum, rhodium, ruthenium, palladium, osmium or iridium metals, or organometallic compounds thereof, and combinations of any two or more thereof. Component (E) is typically a platinum-based catalyst that can dramatically accelerate the curing of the composition. Examples of platinum-based catalysts include platinum fine 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.

[0057] In various embodiments, component (E) is a hydrosilylation reaction catalyst comprising a complex of platinum with a low molecular weight organopolysiloxane, including a complex of platinum with 1,3-divinyl-1,1,3,3-tetramethyldisiloxane. These complexes may be microencapsulated in a resin matrix. In a specific embodiment, the catalyst includes a complex of platinum with 1,3-divinyl-1,1,3,3-tetramethyldisiloxane.

[0058] Examples of hydrosilylation catalysts suitable for component (E) are described in, for example, 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 European Patent No. 0347895(B). Microencapsulated hydrosilylation catalysts and their preparation methods are exemplified in U.S. Patent Nos. 4,766,176 and 5,017,654.

[0059] The amount of component (E) in the composition is an amount effective for promoting the curing of the composition. Specifically, in order to sufficiently cure the composition, the content of component (E) is typically an amount such that the content of the catalytic metal in component (E) relative to the composition is about 0.01 to about 500 ppm, alternatively about 0.01 to about 100 ppm, alternatively about 0.01 to about 50 ppm, alternatively about 0.1 to about 10 ppm, calculated as a mass unit.

[0060] In various embodiments, the curable silicone composition includes (F) a hydrosilylation reaction inhibitor to control the cure rate of the curable silicone composition. In certain embodiments, component (F) includes, but is not limited to, an alkyne alcohol such as 2-methyl-3-butyn-2-ol, 3,5-dimethyl-1-hexyn-3-ol, or 2-phenyl-3-butyn-2-ol, 1-ethynyl-cyclohexan-1-ol; an ene-yne ​​compound 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, tris[(1,1-dimethyl-2-propynyl)oxy]methylsilane, diallylmaleate, or benzotriazole, and component (F) can be incorporated into the composition as an optional component.

[0061] The amount of component (F) in the composition is not particularly limited, but when contained, it is typically about 1 to about 10,000 ppm, alternatively about 10 to about 5,000 ppm, in terms of mass units for the composition. This is because, when the amount of component (F) is equal to or greater than the lower limit of the above range, the storage stability of the composition is good, whereas, when the amount of component (F) is equal to or less than the upper limit of the above range, the curability of the composition at low temperatures is good.

[0062] The composition may contain (G) an adhesion promoter to improve adhesion of the cured product to the substrate it comes into contact with during curing. In certain embodiments, the adhesion promoter of component (G) is typically an organosilicon compound having at least one alkoxy group bonded to a silicon atom in the molecule. The alkoxy group is exemplified by methoxy, ethoxy, propoxy, butoxy, and methoxyethoxy groups, with methoxy being the most typical. In addition, the non-alkoxy group bonded to the silicon atom of the organosilicon compound is exemplified by substituted or unsubstituted monovalent hydrocarbon groups such as alkyl groups, alkenyl groups, aryl groups, aralkyl groups, halogenated alkyl groups, etc.; epoxy group-containing monovalent organic groups such as 3-glycidoxypropyl groups, 4-glycidoxybutyl groups, or similar glycidoxyalkyl groups; 2-(3,4-epoxycyclohexyl)ethyl groups, 3-(3,4-epoxycyclohexyl)propyl groups, or similar epoxycyclohexylalkyl groups; and 4-oxiranylbutyl groups, 8-oxiranyloctyl groups, or similar oxiranylalkyl groups; acryl group-containing monovalent organic groups such as 3-methacryloxypropyl groups; and hydrogen atoms.The organosilicon compound generally has silicon-bonded alkenyl groups or silicon-bonded hydrogen atoms.In addition, due to its ability to provide good adhesion to various types of substrates, the organosilicon compound generally has at least one epoxy group-containing monovalent organic group in the molecule. This type of organosilicon compound is exemplified by organosilane compounds, organosiloxane oligomers, and alkyl silicates. The molecular structure of the organosiloxane oligomer or alkyl silicate is exemplified by a linear structure, a partially branched linear structure, a branched structure, a cyclic structure, and a net structure. The linear structure, the branched structure, and the net structure are typical.Organosilicon compounds of this type are exemplified by silane compounds such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and the like; siloxane compounds having at least one silicon-bonded alkenyl group or silicon-bonded hydrogen atom and at least one silicon-bonded alkoxy group in the molecule; mixtures of silane compounds or siloxane compounds having at least one silicon-bonded alkoxy group in the molecule with siloxane compounds having at least one silicon-bonded hydroxyl group and at least one silicon-bonded alkenyl group in the molecule; and methyl polysilicate, ethyl polysilicate, and epoxy group-containing ethyl polysilicate.

[0063] In the present composition, the amount of component (G) is not particularly limited, but is typically up to 10 parts by weight per 100 parts by weight of the combined weight of components (A) to (C) in order to achieve good adhesion to substrates that come into contact during curing.

[0064] The refractive index of the composition at 25°C is not limited, but is typically in the range of 1.415 to 1.470. The viscosity of the composition at 25°C is not limited, but is typically in the range of 10 to 200 Pa·s measured at a shear rate of 1 / s. The thixotropy index of the 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 thixotropy index of the composition is equal to or greater than the lower limit of the above range, the composition can retain its shape after being dispensed, while, if the thixotropy index of the composition is equal to or less than the upper limit of the above range, the composition can form an appropriate shape, such as a convex lens shape, when dispensed. As used herein, the "thixotropy index" is calculated from the ratio of the viscosities of the composition at 25°C at shear rates of 1 / s and 10 / s ([viscosity at 1 / s] / [viscosity at 10 / s]) measured with a rheometer using a spindle. EXAMPLES

[0065] The curable silicone 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 descriptions of the examples listed below.

[0066] [Gel Permeation Chromatography (GPC)] GPC data for components (a1) and (a2) were collected using a Waters 2695 separation module equipped with a Waters 2414 refractive index detector (RID). Three (7.8 x 300 mm) Styragel HR columns (molecular weight separation range 100-4,000,000) and one Styragel guard column (4.6 x 30 mm) with toluene were used. Samples were prepared as 0.5 wt% solutions in toluene and filtered through 0.45 micron PTFE syringe filters. A flow rate of 1 milliliter per minute was used, with detector and column temperatures of 45°C, injection volume of 100 microliters, and run time of 60 minutes. Number average molecular weights (Mn) were calculated against linear polystyrene standards covering a molecular weight range of 580-2,610,000.

[0067] [Refractive index] The refractive index of the curable silicone composition at 25° C. was measured at a wavelength of 589 nm under an atmospheric pressure of 1013 mbar according to the DIN 51423 standard using an Abbe refractometer manufactured by ATAGO Co., Ltd.

[0068] [viscosity] The viscosity of each organosiloxane oligomer and organopolysiloxane at 25° C. was measured for 1 minute using a DV1 VISCOMETER (Brookfield) with spindle #CP-40Z.

[0069] [Thixotropy index] The viscosity of the curable silicone composition at 25°C was measured with an ARES G2 rheometer (TA instruments) using a spindle (part number 543661.901, stainless steel, 25 mm, 2°, ETC cone). The viscosity (Pa·s) was measured at shear rates of 1 / s and 10 / s for 1 minute. The thixotropy index was calculated as the ratio of the viscosities at shear rates of 1 / s and 10 / s = [viscosity at 1 / s] / [viscosity at 10 / s].

[0070] [hardness] The curable silicone composition was poured into a mold (10 mm thick) having a recess of a specified shape, and then cured for 1 hour at 150° C. The hardness of the cured product was measured using a Type D durometer hardness tester and a Type A durometer hardness tester using a Shore A durometer specified in ASTM D2240.

[0071] [Transmittance] The curable silicone composition was poured into a mold (1 mm thick) and sandwiched between microslide glasses (Matsunami Glass Industry Co., Ltd., product number 9213). The assembled sample was cured at 190° C. for 30 minutes. The transmittance (%) at wavelengths of 450 nm, 550 nm, and 700 nm was measured at room temperature using the method specified in ASTM D1003 (UV-visible spectrophotometer, Konica Minolta CM-3600A, reference = water).

[0072] [Examples 1 to 8 and Comparative Examples 1 to 11] The following components were mixed uniformly in the amounts shown in Tables 1 to 4 to produce a curable silicone composition. When component (A) was solid at 25°C, it had a high viscosity, so component (A) was added to the other components using a solvent such as toluene or xylene. Then, to prepare a solventless composition, the solvent was evaporated and replaced with other components that facilitate mixing. For example, component (B) was first added to a solution of component (A) dissolved in a solvent. Then, the solvent was removed under reduced pressure by heating while bubbling with nitrogen. After cooling to room temperature, component (C) was added. The mixture was mixed at room temperature. Furthermore, other components were added to the mixture and mixed at room temperature. The obtained composition and cured product were evaluated as described above. These results are shown 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 groups in components (A) to (C).

[0073] The following organopolysiloxane resins were used as component (A): (a1) The average unit formula: [(CH3)3SiO 1 / 2 ] 0.40 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.04 (SiO 4 / 2 ) 0.56 The organopolysiloxane resin has a vinyl group content of about 1.9 mass%, a number average molecular weight (Mn) of about 5,000, and is a solid at 25°C. (a2) The average unit formula: [(CH3)3SiO 1 / 2 ] 0.40 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.10 (SiO 4 / 2 ) 0.50 The organopolysiloxane resin has a vinyl group content of about 3.0 mass %, a number average molecular weight (Mn) of about 3,000, and is a solid at 25°C.

[0074] The following organopolysiloxane resins were used as comparisons for component (A): (a3) The average unit formula: [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.25 (C6H5SiO 3 / 2 ) 0.75 The organopolysiloxane resin has a vinyl group content of 5.62 mass% and is a solid at 25°C. (a4) The average unit formula: [(CH3)3SiO 1 / 2 ] 0.14 [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.11 (CHSiO 3 / 2 ) 0.53 (C6H5SiO 3 / 2 ) 0.22 The organopolysiloxane resin has a vinyl group content of about 2.2% by mass and is a solid at 25°C.

[0075] The following organosiloxane oligomers were used as component (B): (b1) the following formula: (CH2=CH)(CH3)2SiO(C6H5)2SiOSi(CH3)2(CH=CH2) It is an organosiloxane oligomer having a viscosity of 8.7 mPa·s and a vinyl group content of approximately 14.06% by mass. (b2) the following formula: H(CH3)2SiO(C6H5)2SiOSi(CH3)2H having a viscosity of 4.4 mPa s and a silicon-bonded hydrogen atom content of approximately 0.61 mass%. (b3) The average unit formula: [(CH3)2SiO 1 / 2 ] 0.60 (C6H5SiO 3 / 2 ) 0.40 having a viscosity of 29 mPa·s and a content of silicon-bonded hydrogen atoms of approximately 0.65% by mass.

[0076] The following organopolysiloxanes were used as comparisons for component (B): (b4) the following formula: (CH2=CH)(CH3)2SiO[(C6H5)(CH3)SiO] 20 Si(CH3)2(CH=CH2) It is an organopolysiloxane having a viscosity of 2,300 mPa·s and a vinyl group content of approximately 1.43% by mass. (b5) the following formula: (CH2=CH)(CH3)2SiO[(CH3)2SiO] 200 [(C6H5)2SiO] 50 Si(CH3)2(CH=CH2) It is an organopolysiloxane having a viscosity of 14,000 mPa·s and a vinyl group content of approximately 0.22% by mass.

[0077] The following organopolysiloxanes were used as component (C): (c1) the following formula: (CH2=CH)(CH3)2SiO[(CH3)2SiO]7Si(CH3)2(CH=CH2) It is an organopolysiloxane having a viscosity of 7 mPa·s and a vinyl group content of approximately 7.49% by mass. (c2) the following formula: (CH2=CH)(CH3)2SiO[(CH3)2SiO] 45 Si(CH3)2(CH=CH2) It is an organopolysiloxane having a viscosity of 60 mPa·s and a vinyl group content of approximately 1.66% by mass. (c3) the following formula: H(CH3)2SiO[(CH3)2SiO] 16 Si(CH3)2H having a viscosity of 15 mPa s and a content of silicon-bonded hydrogen atoms of approximately 0.15 mass%. (c4) The average unit formula: [(CH3)2HSiO 1 / 2 ] 0.65 (SiO 4 / 2 )0.35 The organopolysiloxane resin has a viscosity of 23 mPa s and a content of silicon-bonded hydrogen atoms of approximately 0.96 mass%.

[0078] The following fumed silica was used as component (D): (d1) BET specific surface area is 230m 2 / g fumed silica (Tokuyama REOLOSIL DM-30S)

[0079] The following hydrosilylation reaction catalyst was used as component (E): (e1) Complex of platinum with 1,3-divinyl-1,1,3,3-tetramethyldisiloxane in 1,3-divinyl-1,1,3,3-tetramethyldisiloxane solution (platinum content = 4% by mass)

[0080] The following hydrosilylation inhibitors were used as component (F): (f1) 1-ethynyl-cyclohexan-1-ol (f2) 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane

[0081] The following adhesion promoters were used as component (G): (g1) 1,6-bis(trimethoxysilyl)hexane (g2) The average unit formula: [(CH2=CH)(CH3)2SiO 1 / 2 ] 0.18 (C6H5SiO 3 / 2 ) 0.54 [CH2(O)CHCH2O(CH2)3SiO 3 / 2 ] 0.28 The organopolysiloxane resin represented by

[0082] [Table 1]

[0083] [Table 2]

[0084] [Table 3]

[0085] [Table 4]

[0086] Examples IE1-IE8 are representative examples of curable silicone compositions described herein that exhibit thixotropic properties (thixotropy index ≧1.5) along with transparency (transmittance >99% at 450 nm). As shown in Comparative Example CE2, thixotropic properties are not obtained without component (D). Meanwhile, Comparative Examples CE3 and CE4 show poor optical properties of 96.39% and 96.86% at 450 nm, respectively. Comparing Comparative Example CE4 with Examples IE5-IE8, it is believed that the use of component (B) provides transparency along with thixotropic properties.

[0087] According to Comparative Example CE5, a non-homogeneous cloudy liquid is obtained because Comparative Example CE5 is not compatible with Components (A) and (C). Comparative Examples CE6 to CE9 show curable silicone compositions using Comparative Examples CE6 and CE9, which show poor light transmittance of less than 99% at 450 nm.

[0088] In the case of comparative example CE1, which uses 65.06% by weight of component (a1), a very viscous liquid is obtained. [Industrial Applicability]

[0089] The curable silicone composition of the present invention has excellent thixotropic properties and can be cured to form a transparent cured product, even though it contains a large amount of organopolysiloxane resin. Therefore, the curable silicone composition is useful as a sealant, adhesive, or coating for optical semiconductor elements in electric / electronic devices.

Claims

1. (A) an average unit formula of: (R １ ３ Yes １／２ ) ａ (R ２ R １ ２ Yes １／２ ) ｂ (Yes) ４／２ ) ｃ (HO １／２ ) ｄ (In the formula, each R １ are independently alkyl groups, and R ２ is an alkenyl group, and "a," "b," "c," and "d" are numbers that satisfy the conditions a≧0, b>0, 0.3≦c≦0.7, 0≦d≦0.05, and a+b+c=1; and (B) The viscosity at 25°C is 1,000 mPa·s or less, １ ) an organosiloxane oligomer having at least one silicon-bonded alkenyl group and at least one silicon-bonded aryl group in the molecule; (B ２ ) an organosiloxane oligomer having at least one silicon-bonded hydrogen atom and at least one silicon-bonded aryl group in the molecule, and component (B １ ) and (B ２ and a mixture of (C) (C １ ) having at least one alkenyl group in the molecule, and a silicon-bonded aryl group and SiO ４／２ Organopolysiloxane having no units, (C ２ an organopolysiloxane having at least one silicon-bonded hydrogen atom in the molecule and no silicon-bonded aryl groups, and component (C １ ) and (C ２ and a mixture of (D) a silica filler; and (E) a catalytic amount of a hydrosilylation reaction catalyst; A curable silicone composition in which, based on the total mass of components (A) to (C), the amount of component (A) is in the range of 40.0 to 65.0 mass%, the amount of component (B) is in the range of 1.0 to 55.0 mass%, and the amount of component (C) is in the range of 0 to 50.0 mass%, and the amount of component (D) is in the range of 1 to 10 parts by mass per 100 parts by mass of the total mass of components (A) to (C), with the proviso 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.

2. Ingredients (B １ )but, (B １１ ) a compound having the following general formula: R ２ R ３ ２ SiO(R ３ ２ SiO) ｍ SiR ３ ２ R ２ (In the formula, each R ２ are independently an alkenyl group, and each R ３ are independently an alkyl group or an aryl group, provided that at least one R ３ is an aryl group, and "m" is an integer from 0 to 10), and (B １２ ) the average unit formula below: (R ２ R ３ ２ SiO １／２ ) ｅ (R ３ SiO ３／２ ) ｆ (In the formula, R ２ and R ３ is as defined above, and "e" and "f" are numbers that satisfy the conditions e > 0, f > 0, and e + f = 1.

3. Ingredients (B １１ ) has the following formula: (CH ２ =CH)(CH ３ ) ２ SiO(C ６ H ５ ) ２ SiOSi(CH ３ ) ２ (CH=CH ２ ) (CH ２ =CH)(CH ３ ) ２ SiO(C ６ H ５ )(CH ３ )SiOSi(CH ３ ) ２ (CH=CH ２ ) (CH ２ =CH)(CH ３ )(C ６ H ５ )SiOSi(CH ３ )(C ６ H ５ )(CH=CH ２ ) and component (B) is at least one selected from organosiloxane oligomers represented by the formula: １２ ) has the following general unit formula: [(CH ２ =CH)(CH ３ ) ２ SiO １／２ ] ｅ [(C ６ H ５ )SiO ３／２ ] ｆ 3. The curable silicone composition according to claim 2, wherein the organosiloxane oligomer is represented by the formula: wherein "e" and "f" are as defined above.

4. Ingredients (B ２ )but, (B ２１ ) a compound having the following general formula: HR ３ ２ SiO(R ３ ２ SiO) ｍ SiR ３ ２ H (In the formula, each R ３ are independently an alkyl group or an aryl group, provided that at least one R ３ is an aryl group, and "m" is an integer from 0 to 10), and (B ２２ ) the average unit formula below: (R ３ ２ HSiO １／２ ) ｅ (R ３ SiO ３／２ ) ｆ (In the formula, R ３ is as defined above, and "e" and "f" are numbers that satisfy the conditions e > 0, f > 0, and e + f = 1.

5. Ingredients (B ２１ ) has the following formula: H(H) ３ ) ２ SiO (C) ６ H ５ ) ２ SiOSi(CH ３ ) ２ H H(CH ３ ) ２ SiO(C ６ H ５ )(CH ３ )SiOSi(CH ３ ) ２ H At least one organosiloxane oligomer selected from the group consisting of: Ingredients (B ２２ ) has the following general unit formula: [(CH ３ ) ２ HSiO １／２ ] ｅ [(C ６ H ５ )SiO ３／２ )] ｆ 5. The curable silicone composition according to claim 4, wherein the organosiloxane oligomer is represented by the formula: wherein "e" and "f" are as defined above.

6. (F) a hydrosilylation reaction inhibitor in an amount of 0.1 to 10,000 ppm in this component, calculated in units of mass relative to the composition.

10. The curable silicone composition of claim 1, further comprising:

7. (G) An adhesion promoter in an amount of up to 10 parts by weight per 100 parts by weight of the total weight of components (A) to (C). The curable silicone composition according to any one of claims 1 to 6, further comprising: