Sealing resin composition and sealing sheet

1. A sealing resin composition, comprising:

(A) at least one epoxy resin;

(B) calcined hydrotalcite;

(C) talc; and

(D) silica,

wherein, based on 80 parts by mass of (A) said at least one epoxy resin:

(B) said calcined hydrotalcite is present in an amount of 5 to 38 parts by mass;

(C) said talc is present in an amount of 2 to 16 parts by mass; and

(D) said silica is present in an amount of 6 to 16 parts by mass,

which affords a cured product of thickness of 20 μm having a transmittance of not less than 84% at 450 nm when the resin composition is heat hardened at 110° C. for 30 min.

2. The resin composition according to claim 1 , wherein (A) said epoxy resin has a transmittance of not less than 90%.

3. The resin composition according to claim 2 , further comprising:

(E) at least one thermoplastic resin in an amount of 1 to 40 parts by mass, based on 80 parts by mass of (A) said at least one epoxy resin.

4. The resin composition according to claim 3 , wherein (E) said at least one thermoplastic resin is a phenoxy resin.

5. The resin composition according to claim 4 , wherein (E) said at least one thermoplastic resin has a transmittance of not less than 90%.

6. The resin composition according to claim 3 , wherein (E) said at least one thermoplastic resin has a transmittance of not less than 90%.

7. The resin composition according to claim 1 , further comprising:

(E) at least one thermoplastic resin in an amount of 1 to 40 parts by mass, based on 80 parts by mass of (A) said at least one epoxy resin.

8. The resin composition according to claim 7 , wherein (E) said at least one thermoplastic resin is a phenoxy resin.

9. The resin composition according to claim 8 , wherein (E) said at least one thermoplastic resin has a transmittance of not less than 90%.

10. The resin composition according to claim 7 , wherein (E) said at least one thermoplastic resin has a transmittance of not less than 90%.

11. The resin composition according to claim 1 , further comprising:

(F) at least one surface treating agent in an amount of 0.1 to 3 parts by mass, based on 80 parts by mass of (A) said at least one epoxy resin.

12. The resin composition according to claim 11 , wherein (F) said at least one surface treating agent is a silane coupling agent.

13. The resin composition according to claim 1 , which affords a cured product having a transmittance of not less than 84%.

14. The resin composition according to claim 1 , further comprising:

(G) at least one curing agent in an amount of 0.1 to 3 parts by mass, based on 80 parts by mass of (A) said at least one epoxy resin.

15. The resin composition according to claim 14 , wherein (G) said at least one curing agent is an ion liquid.

16. A sealing sheet, comprising a support and a layer of a resin composition according to claim 1 formed on said support.

17. The sealing sheet according to claim 16 , wherein the flooded area from the end surface of the sealing sheet is 0 to 0.5 mm from the sheet end surface.

18. The resin composition according to claim 1 , wherein the average particle size of said talc is 0.5 to 2 μm.

19. The resin composition according to claim 1 , wherein the BET specific surface area of said silica is 2720 to 27 m 2 /g.

20. The resin composition according to claim 1 , wherein the BET specific surface area of said calcined hydrotalcite is 5 to 200 m 2 /g.

21. The resin composition according to claim 1 , wherein the average particle size of said talc is 0.5 to 2 μm, the BET specific surface area of said silica is 2720 to 27 m 2 /g, and the BET specific surface area of said calcined hydrotalcite is 5 to 200 m 2 /g, and which affords a cured product of thickness of 20 μm having a transmittance of not less than 84% when the resin composition is heat hardened at 110° C. for 30 min.

22. The resin composition according to claim 1 , wherein at least 10 mass % of the whole epoxy resin is liquid at room temperature (25° C.).