Thermosetting silicone resin composition for reflector of LED, reflector for LED using the same and optical semiconductor apparatus

1. A thermosetting silicone resin composition for a reflector of an LED, comprising:

(A) 45 to 90 parts by mass of an organopolysiloxane represented by the following average compositional formula (1), and having at least two alkenyl groups in one molecule,

R 1 a R 2 b R 3 c (OR 0 ) d SiO (4-a-b-c-d)/2   (1)

wherein R 1 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having neither an alkenyl group nor an aryl group; R 2 represents an aryl group; R 3 represents an alkenyl group; R 0 represents a hydrogen atom, a methyl group or an ethyl group; “a” represents a number of 0.4 to 1.0; “b” represents a number of 0 to 0.5; “c” represents a number of 0.05 to 0.5; “d” represents a number of 0 to 0.5; and a+b+c+d=1.0 to 2.0;

(B) 10 to 55 parts by mass of a linear organohydrogenpolysiloxane represented by the following general formula (2) and a branched organohydrogenpolysiloxane represented by the following average compositional formula (3), which has at least two hydrogen atoms directly bonded to a silicon atom in one molecule, provided that the sum of Component (A) and Component (B) is 100 parts by mass,

wherein R 4 each independently represents a substituted or unsubstituted monovalent hydrocarbon group having no alkenyl group; R 5 represents hydrogen; and a repeating unit “n” represents an integer of 1 to 10,

R 7 e R 8 f H g SiO (4-e-f-g)/2   (3)

wherein R 7 each independently represents a substituted or unsubstituted monovalent hydrocarbon group containing neither an alkenyl group nor an aryl group; R 8 represents an aryl group; “e” represents a number of 0.6 to 1.5; “f” represents a number of 0 to 0.5; “g” represents a number of 0.4 to 1.0; and e+f+g=1.0 to 2.5;

(C) a catalytic amount of an addition reaction catalyst;

(D) 3 to 200 parts by mass of a white pigment selected from titanium oxide, zinc oxide, mangesium oxide, barium carbonate, mangesium silicate, zinc sulfate and barium sulfate; and

(E) 100 to 1000 parts by mass of an inorganic filler other than Component (D), Component (E) having an average particle diameter of 10 to 20 μm;

wherein an amount of Component (B) is 70% by mass or more based on a whole hydrogen atom-containing silicon compound having at least two hydrogen atoms directly bonded to a silicon atom in one molecule contained in the thermosetting silicone resin composition.

2. The thermosetting silicone resin composition for a reflector of an LED according to claim 1 , wherein an average particle diameter of Component (D) is 0.05 to 5 μm.

3. The thermosetting silicone resin composition for a reflector of an LED according to claim 2 , further comprising (F) a mold releasing agent.

4. The thermosetting silicone resin composition for a reflector of an LED according to claim 3 , wherein the composition is a solid at room temperature.

5. The thermosetting silicone resin composition for a reflector of an LED according to claim 2 , wherein the composition is a solid at room temperature.

6. The thermosetting silicone resin composition for a reflector of an LED according to claim 1 , further comprising (F) a mold releasing agent.

7. The thermosetting silicone resin composition for a reflector of an LED according to claim 6 , wherein the composition is a solid at room temperature.

8. The thermosetting silicone resin composition for a reflector of an LED according to claim 1 , wherein the composition is a solid at room temperature.

9. A reflector for an LED molded by the thermosetting silicone resin composition for a reflector of an LED according to claim 1 .

10. An optical semiconductor apparatus using the reflector for an LED according to claim 9 .

11. The thermosetting silicone resin composition for a reflector of an LED according to claim 1 , wherein Component (E) has a content of particles having a particle size exceeding 50 μm of 1% by mass or less.