Curable composition and method for manufacturing the same

A curable composition comprising:

• (A) a branched polymer having an average unit formula (I′):
• [(R″)2SiO2/2]a″[(CH2═CH)(R″)2SiO1/2]b″[R″SiO3/2]c″[O1/2Si(R″)2(CH2CH2)(R″)2SiO1/2]e″ (I′),
• wherein
• R″ is a substituted or unsubstituted mono-valent hydrocarbon group, each of R″ is the same with or different from each other,
• a″ is an integer ranging from 0 to 200,
• b″ is an integer ranging from 3 to 6,
• c″ is an integer ranging from 1 to 4, and
• e″ is an integer ranging from 2 to 200;
• (B) a branched organopolysiloxane having at least one silicon-bonded alkenyl group and having a siloxane unit of formula R4SiO3/2 wherein R4 is a substituted or unsubstituted mono-valent hydrocarbon group, and wherein the amount of component (B) is about 1 part by weight to about 9900 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:
• (R52SiO2/2)f(R63SiO1/2)g(R7SiO3/2)h(SiO4/2)i(CH2CH2)j (II);
• wherein R5, R6 and R7 are independently H or a substituted or unsubstituted mono-valent hydrocarbon group, wherein each of R5 is the same with or different from each other, each of R6 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.