Curable organopolysiloxane composition, optical device sealing material, and optical device

1. A curable organopolysiloxane composition containing:

(A) a compound shown by the following average composition formula (1),

wherein R 1 represents the same or different aliphatic unsaturated groups; R 2 represents the same or different unsubstituted or substituted monovalent hydrocarbon groups; R 3 represents the same or different unsubstituted or substituted aliphatic hydrocarbon groups; Ar represents the same or different unsubstituted or substituted aryl groups which may contain a heteroatom; and “n” and “m” represent positive numbers which satisfy n≧1, m≧1, and n+m≧10,

(B) a hydrogen atom-containing organic silicon compound having at least two silicon atom-bonded hydrogen atoms per one molecule while not having an aliphatic unsaturated group, and

(C) a hydrosilylatation catalyst which contains a platinum group metal,

wherein the compound shown by the formula (1) of the component (A) is synthesized via a cyclic oligomer shown by the following average composition formula (2),

wherein R 3 and Ar represent the same meanings as before; and n′ and m′ represent positive numbers which satisfy n′≧1 and m′≧1, and wherein the curable organopolysiloxane composition further contains the cyclic oligomer shown by the formula (2).

2. The curable organopolysiloxane composition according to claim 1 , wherein Ar in the formula (1) and formula (2) is a phenyl group.

3. The curable organopolysiloxane composition according to claim 1 , wherein the component (B) is an organohydrogen polysiloxane shown by the following average composition formula (3),

R 5 b H c SiO (4-b-c)/2   (3)

wherein R 5 represents the same or different unsubstituted or substituted silicon atom-bonded monovalent hydrocarbon groups other than an aliphatic unsaturated group; and “b” and “c” represent positive numbers which satisfy 0.7≦b≦2.1, 0.001≦c≦1.0, and 0.8≦b+≦c≦3.0.

4. The curable organopolysiloxane composition according to claim 2 , wherein the component (B) is an organohydrogen polysiloxane shown by the following average composition formula (3),

R 5 b H c SiO (4-b-c)/2   (3)

wherein R 5 represents the same or different unsubstituted or substituted silicon atom-bonded monovalent hydrocarbon groups other than an aliphatic unsaturated group; and “b” and “c” represent positive numbers which satisfy 0.7≦b≦2.1, 0.001≦c≦1.0, and 0.8≦b+c≦3.0.

5. The curable organopolysiloxane composition according to claim 1 , wherein the curable organopolysiloxane composition contains further, as the component (D), an organic silicon compound shown by the following average composition formula (4) and having at least one R 4 SiO 3/2 unit per one molecule,

R 4 a SiO (4-a)/2   (4)

wherein R 4 represents the same or different unsubstituted or substituted monovalent hydrocarbon groups, wherein at least one of R 4 is an aryl group, and 0.1 to 40 mole % of entirety of R 4 is an aliphatic unsaturated group; and “a” represents a positive number which satisfies 1≦a<3.

6. The curable organopolysiloxane composition according to claim 2 , wherein the curable organopolysiloxane composition contains further, as the component (D), an organic silicon compound shown by the following average composition formula (4) and having at least one R 4 SiO 3/2 unit per one molecule,

R 4 a SiO (4-a)/2   (4)

wherein R 4 represents the same or different unsubstituted or substituted monovalent hydrocarbon groups, wherein at least one of R 4 is an aryl group, and 0.1 to 40 mole % of entirety of R 4 is an aliphatic unsaturated group; and “a” represents a positive number which satisfies 1≦a<3.

7. The curable organopolysiloxane composition according to claim 3 , wherein the curable organopolysiloxane composition contains further, as the component (D), an organic silicon compound shown by the following average composition formula (4) and having at least one R 4 SiO 3/2 unit per one molecule,

R 4 a SiO (4-a)/2   (4)

wherein R 4 represents the same or different unsubstituted or substituted monovalent hydrocarbon groups, wherein at least one of R 4 is an aryl group, and 0.1 to 40 mole % of entirety of R 4 is an aliphatic unsaturated group; and “a” represents a positive number which satisfies 1≦a<3.

8. The curable organopolysiloxane composition according to claim 4 , wherein the curable organopolysiloxane composition contains further, as the component (D), an organic silicon compound shown by the following average composition formula (4) and having at least one R 4 SiO 3/2 unit per one molecule,

R 4 a SiO (4-a)/2   (4)

wherein R 4 represents the same or different unsubstituted or substituted monovalent hydrocarbon groups, wherein at least one of R 4 is an aryl group, and 0.1 to 40 mole % of entirety of R 4 is an aliphatic unsaturated group; and “a” represents a positive number which satisfies 1≦a<3.

9. The curable organopolysiloxane composition according to claim 8 , wherein the curable organopolysiloxane composition is capable of giving a cured product having refractive index of 1.54 or higher.

10. An optical device sealing material comprising the curable organopolysiloxane composition according to claim 9 .

11. An optical device which is sealed by the cured product of the optical device sealing material according to claim 10 .