Curable composition and method for manufacturing the same

1. A curable composition comprising:

(A) a polymer having at least two silicon-bonded alkenyl groups and having an average unit formula (I′):

(R 1 2 SiO 2/2 ) a1 (R 2 3 SiO 1/2 ) b1 (CH 2 CH 2 ) e1   (I′);

wherein R 1 and R 2 are independently a substituted or unsubstituted mono-valent hydrocarbon group, each of R 1 is the same with or different from each other, each of R 2 is the same with or different from each other, and a1≧0, b1>0, and e1>0;

(B) a branched organopolysiloxane having at least one silicon-bonded alkenyl group and having a siloxane unit of formula R 4 SiO 3/2 wherein R 4 is a substituted or unsubstituted mono-valent hydrocarbon group, and wherein the amount of component (B) is about 200 parts by weight to about 3000 parts by weight, based on 100 parts by weight of component (A);

(C) an organopolysiloxane having an average unit formula (II) being capped with H:

(R 5 2 SiO 2/2 ) f (R 6 3 SiO 1/2 ) g (R 7 SiO 3/2 ) h (SiO 4/2 ) i (CH 2 CH 2 ) j   (II);

wherein R 5 , R 6 and R 7 are independently H or a substituted or unsubstituted mono-valent hydrocarbon group, wherein each of R 5 is the same with or different from each other, each of R 6 is the same with or different from each other, f>0, g>0, h≧0, i≧0, j≧0, and the amount of component (C) is about 1 parts by weight to about 300 parts by weight, based on 100 parts by weight of the total amount of components (A) and (B); and

(D) a catalyst.

2. The curable composition of claim 1 , wherein R 1 , R 2 , and R 4 are independently an alkenyl, an alkyl or an aryl group; R 5 , R 6 and R 7 are independently H, an alkyl or an aryl group.

3. The curable composition of claim 1 , wherein about 0.1 percent by mole to about 40 percent by mole of R 1 and R 2 are alkenyl groups, and at least about 10 percent by mole of R 1 and R 2 are aryl groups, based on the total amount of R 1 and R 2 .

4. The curable composition of claim 1 , wherein:

a1 is an integer ranging from about 0 to about 200;

b1 is an integer ranging from about 1 to about 200; and

e1 is an integer ranging from about 2 to about 200.

5. The curable composition of claim 1 , wherein the component (A) has the following structure:

wherein X is

p is an integer ranging from 1 to 4, each of p is the same with or different from each other;

q is an integer ranging from 1 to 4, each of q is the same with or different from each other;

t is an integer ranging from 0 to 50; and

R″ is independently a substituted or unsubstituted mono-valent hydrocarbon group, each of R″ is the same with or different from each other.

6. The curable composition of claim 5 , wherein R″ is C 1 -C 3 alkyl or an aryl group.

7. The curable composition of claim 6 , wherein R″ is methyl or phenyl.

8. The curable composition of claim 5 , wherein about at least 10 percent by mole of R″ are aryl group, based on the total amount of R″.

9. The curable composition of claim 1 , wherein component (A) is prepared by an addition reaction of a siloxane having at least two alkenyl groups and a siloxane having at least two H.

10. The curable composition of claim 9 , wherein:

the siloxane having at least two alkenyl groups has an average unit formal (III′):

(R 1′ 2 SiO 2/2 ) a1′ (R 2′ 3 SiO 1/2 ) b1′   (III′); and

the siloxane having at least two H has an average unit formula (IV′):

(R 5′ 2 SiO 2/2 ) f1′ (R 6′ 3 SiO 1/2 ) g1′   (IV′),

wherein R 1′ , R 2′ , R 5′ and R 6′ are independently a substituted or unsubstituted mono-valent hydrocarbon group, each of R 1′ is the same with or different from each other, each of R 2′ is the same with or different from each other, each of R 5′ is the same with or different from each other, and each of R 6′ is the same with or different from each other, and a 1′≧0, b1′>0, f1′≧0 and g1′>0.

11. The curable composition of claim 1 , wherein component (B) has at least one silicon-bonded alkenyl group and at last one silicon-bonded aryl group.

12. The curable composition of claim 1 , wherein about at least 10 percent by mole of R 4 are aryl groups, based on the total amount of R 4 .

13. The curable composition of claim 1 , wherein component (B) has an average unit formula (V):

(R 4 SiO 3/2 ) k [(CH 2 ═CH)(R 8 ) 2 SiO 1/2 ] 1-k   (V),

wherein R 4 is as defined in claim 1 , R 8 is independently a substituted or unsubstituted mono-valent hydrocarbon group, each of R 8 is the same with or different from each other, and k ranges from about 0.5 to about 0.95.

14. The curable composition of claim 13 , wherein R 4 is an aryl group or C 1 -C 3 alkyl, R 8 is independently an aryl group or C 1 -C8alkyl and k ranges from about 0.6 to about 0.9.

15. The curable composition of claim 1 , wherein the amount of component (B) is about 200 parts by weight to about 3000 parts by weight, based on 100 parts by weight of component (A).

16. The curable composition of claim 13 , wherein the amount of component (B) is about 300 parts by weight to about 2500 parts by weight, based on 100 parts by weight of component (A).

17. The curable composition of claim 1 , wherein about 0.1 percent by mole to about 50 percent by mole of R 5 , R 6 , and R 7 are H, and at last about 10 percent by mole of R 5 , R 6 and R 7 are aryl groups, based on the total amount of R 5 , R 6 and R 7 .

18. The curable composition of claim 1 , wherein:

f is an integer ranging from about 1 to about 50;

g is an integer ranging from about 1 to about 50;

h is an integer ranging from 0 to about 10;

i is an integer ranging from 0 to about 5; and

j is an integer ranging from 0 to about 30.

19. The curable composition of claim 1 , wherein the amount of component (C) is about 10 parts by weight to about 250 parts by weight, based on 100 parts by weight of the total amount of components (A) and (B).

20. The curable composition of claim 19 , wherein the amount of component (C) is about 15 parts by weight to about 200 parts be weight, based on 100 parts by weight of the total amount of components (A) and (B).

21. The curable composition of claim 1 , wherein the catalyst of component (D) is selected from the following group: Pt, Rh, Pd, compounds and complexes of the above, and combinations thereof.

22. The curable composition of claim 1 for use as a packaging material for light emitting diodes.

23. The curable composition of claim 5 for use as a packaging material for light emitting diodes.

24. The semiconductor device, in which semiconductor elements are coated with a cured product of the curable composition according to claim 1 .

25. The semiconductor device according to claim 24 , wherein the semiconductor element are light emitting diodes or light sensors.