Silicone composition and a pressure sensitive adhesive film having a pressure sensitive adhesive layer made from the composition

1. A silicone composition comprising:

(A) a diorganopolysiloxane having at least two alkenyl groups in a molecule and having a viscosity at 25° C. of from 10,000 to 1,000,000 mPa·s, in an amount of from 60 to 80 mass % based on the mass of the composition;

(B) a diorganopolysiloxane having at least one alkenyl group in a molecule, and being raw and rubber-like at 25° C. or having a viscosity at 25° C. of more than 1,000,000 mPa·s, in an amount of from greater than 0 to 10 mass % based on the mass of the composition;

(C) an organopolysiloxane resin represented by the following average unit formula:

(R 1 3 SiO 1/2 ) x (SiO 4/2 ) 1.0

wherein each R 1 represents a halogen-substituted or un-substituted monovalent hydrocarbon group free from an alkenyl group and x is a number from 0.5 to 1.0, in an amount of from 0.5 to 20 mass % based on the mass of the composition;

(D) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule, in a quantity that provides from 0.1 to 10 moles of the silicon-bonded hydrogen atoms in this component per 1 mole of the total alkenyl groups in the composition;

(E) silica fine powder in an amount of from 0.5 to 5 mass % based on the mass of the composition; and

(F) a hydrosilylation catalyst in a quantity that accelerates hydrosilylation of the composition.

2. The silicone composition of claim 1 , further comprising (G) an anchorage additive, in an amount of from 0.1 to 5 mass % based on the mass of the composition.

3. The silicone composition of claim 1 , further comprising (H) a reaction inhibitor, in an amount of from 0.1 to 5 mass % based on the mass of the composition.

4. The silicone composition of claim 1 , further comprising (I) an organic solvent, in an amount such that nonvolatile content in its solution is from 10 to 80 mass % based on the mass of the composition.

5. A pressure sensitive adhesive film comprising a substrate film and a pressure sensitive adhesive layer on a surface of the substrate film, said pressure sensitive adhesive layer formed from a silicone composition comprising:

(A) a diorganopolysiloxane having at least two alkenyl groups in a molecule and having a viscosity at 25° C. of from 10,000 to 1,000,000 mPa·s, in an amount of from 60 to 80 mass % based on the mass of the composition;

(B) a diorganopolysiloxane having at least one alkenyl group in a molecule, and being raw and rubber-like at 25° C. or having a viscosity at 25° C. of more than 1,000,000 mPa·s, in an amount of from greater than 0 to 10 mass % based on the mass of the composition;

(C) an organopolysiloxane resin represented by the following average unit formula:

(R 1 3 SiO 1/2 ) x (SiO 4/2 ) 1.0

wherein each R 1 represents a halogen-substituted or un-substituted monovalent hydrocarbon group free from an alkenyl group and x is a number from 0.5 to 1.0, in an amount of from 0.5 to 20 mass % based on the mass of the composition;

(D) an organohydrogenpolysiloxane having at least two silicon-bonded hydrogen atoms in a molecule, in a quantity that provides from 0.1 to 10 moles of the silicon-bonded hydrogen atoms in this component per 1 mole of the total alkenyl groups in the composition;

(E) silica fine powder in an amount of from 0.5 to 5 mass % based on the mass of the composition; and

(F) a hydrosilylation catalyst in a quantity that accelerates hydrosilylation of the composition.

6. The pressure sensitive adhesive film of claim 5 , wherein the substrate film is formed from polyimide (PI), polyether-ether ketone (PEEK), polyethylene naphthalate (PEN), liquid-crystal polyarylene, polyamidoimide (PAI), polyether sulfine (PES), or polyethylene terephthalate (PET).

7. The pressure sensitive adhesive film of claim 5 , wherein the pressure sensitive adhesive layer has a thickness of from 5 μm to 10 mm.

8. The pressure sensitive adhesive film of claim 5 , wherein the pressure sensitive adhesive layer has a pencil hardness of not less than H as measured according to ASTM D3363.

9. The silicone composition of claim 2 , further comprising (H) a reaction inhibitor, in an amount of from 0.1 to 5 mass % based on the mass of the composition.

10. The silicone composition of claim 9 , further comprising (I) an organic solvent, in an amount such that nonvolatile content in its solution is from 10 to 80 mass % based on the mass of the composition.

11. The pressure sensitive adhesive film of claim 5 , wherein the silicone composition further comprises (G) an anchorage additive, in an amount of from 0.1 to 5 mass % based on the mass of the composition.

12. The pressure sensitive adhesive film of claim 11 , wherein the silicone composition further comprises (H) a reaction inhibitor, in an amount of from 0.1 to 5 mass % based on the mass of the composition.

13. The pressure sensitive adhesive film of claim 12 , wherein the silicone composition further comprises (I) an organic solvent, in an amount such that nonvolatile content in its solution is from 10 to 80 mass % based on the mass of the composition.

14. The pressure sensitive adhesive film of claim 5 , wherein the silicone composition further comprises (H) a reaction inhibitor, in an amount of from 0.1 to 5 mass % based on the mass of the composition.

15. The pressure sensitive adhesive film of claim 5 , wherein the silicone composition further comprises (I) an organic solvent, in an amount such that nonvolatile content in its solution is from 10 to 80 mass % based on the mass of the composition.

16. The silicone composition of claim 1 , wherein the diorganopolysiloxane (B) is present in an amount of from 1 to 10 mass % based on the mass of the composition.