Insulation material, film, circuit board and method of producing them

1. An insulation material which has a dielectric constant of 10 or more, and which comprises

a filler having a dielectric constant of 50 or more and having two peaks in different particle size ranges in a particle size distribution,

an insulating resin, and

a dispersant,

wherein they are combined with each other, and

wherein the filler having a dielectric constant of 50 or more contains a filler having a dielectric constant of 50 or more and a particle size of 1 to 5 μm at a cumulative percentage of 50% and a filler having a dielectric constant of 50 or more and a particle size of 0.01 to 1 μm at a cumulative percentage of 50%.

2. The insulation material according to claim 1 , which contains 30 to 90 parts by volume of the filler having a dielectric constant of 50 or more based on 100 parts by volume of the insulation material.

3. The insulation material according to claim 1 , wherein the filler having a dielectric constant of 50 or more is at least one member selected from the group consisting of barium titanate, strontium titanate, potassium titanate, magnesium titanate, lead titanate, titanium dioxide, barium zirconate, calcium zirconate and lead zirconate.

4. The insulation material according to claim 1 , wherein the insulating resin contains a high molecular weight component having a weight average molecular weight of 10000 or more and capable of forming a film and a thermosetting component.

5. The insulation material according to claim 4 , wherein the insulating resin contains 5 to 95% by weight of the high molecular weight component.

6. The insulation material according to claim 4 , wherein the thermosetting component contains an epoxy resin and a phenol resin which is a curing agent thereof.

7. The insulation material according to claim 4 , wherein the high molecular weight component is at least one component selected from the group consisting of a phenoxy resin, polyamideimide resin, polyacrylonitrile resin, polyphenyleneoxide resin and polyacrylonitrile butadiene resin.

8. A film bondable by thermocompression bonding comprising an insulation material according to claim 1 applied to a metal foil.

9. A film bondable by thermocompression bonding comprising an insulation material according to claim 4 applied to a metal foil and semi-cured.

10. A film bondable by thermocompression bonding comprising an insulation material according to claim 1 applied to a plastic film carrier.

11. A film bondable by thermocompression bonding comprising an insulation material according to claim 4 applied to a plastic film carrier and semi-cured.

12. A film comprising an insulation material according to claim 1 and a conductive layer on both sides of the insulation material.

13. A film comprising an insulation material according to claim 4 and a conductive layer on both sides of the insulation material, wherein the insulation material is cured.

14. A circuit board comprising an insulation material according to claim 1 as an insulating layer of 3 to 100 μm thickness.

15. A circuit board comprising an insulation material according to claim 1 as a thermosetting insulating layer of 3 to 100 μm thickness.

16. A method of producing a circuit board, which comprises applying an insulation material according to claim 1 to a circuit board, thereby forming an insulating layer.

17. A method of producing a circuit board, which comprises applying an insulation material according to claim 4 to a circuit board and thermosetting the insulation material, thereby forming an insulating layer.

18. A method of producing a film, which comprises bonding another metal foil to a resin surface, without a metal foil, of a film according to claim 8 by thermocompression bonding.

19. A method of producing a circuit board, which comprises bonding a film according to claim 8 to a circuit board having a desired circuit pattern by thermocompression bonding, thereby forming an insulating layer.

20. A method of producing a film, which comprises removing a plastic film carrier from a film according to claim 10 , disposing a metal foil on both sides of an insulation material and bonding the metal foil by thermocompression bonding.

21. A method of producing a circuit board, which comprises removing a plastic film carrier from a film according to claim 10 , disposing a circuit board having a desired circuit pattern on both sides of an insulation material and bonding the circuit board by thermocompression bonding, thereby forming an insulating layer.

22. A method of producing a circuit board, which comprises removing a plastic film carrier from a film according to claim 10 , disposing a circuit board having a desired circuit pattern on one side of an insulation material, disposing a conductive metal foil on the other side of the insulation material and bonding the conductive metal foil by thermocompression bonding.

23. A method of producing a circuit board, which comprises

removing a plastic film carrier from a film according to claim 10 and bonding the film to a circuit board having a desired circuit pattern by thermocompression bonding, or removing a plastic film carrier after the film is bonded to a circuit board having a desired circuit pattern by thermocompression bonding, and

forming a conductor on an insulation material by conductive plating, sputtering of a conductive material or application of a conductive paint.

24. A method of producing a circuit board, which comprises forming a conductor on a film according to claim 12 formed on a circuit board by conductive plating, sputtering of a conductive material or application of a conductive paint.

25. The insulation material according to claim 1 , wherein the filler containing two kind of fillers with different particle size has a particle size of 1 to 3 μm at a cumulative percentage of 50%.

26. The insulation material according to claim 1 , wherein the content of the dispersant is 0.001-8% by weight of the filler.

27. An insulation material which has a dielectric constant of 10 or more, and which comprises

a filler having a dielectric constant of 50 or more and having two peaks in different particle size ranges in a particle size distribution,

an insulating resin, and

a dispersant,

wherein they are combined with each other, and

wherein the filler having a dielectric constant of 50 or more contains, based on the total filler, 50% by weight or more of a filler having a dielectric constant of 50 or more and a particle size of 1 to 5 μm at a cumulative percentage of 50% and a remaining filler having a dielectric constant of 50 or more and a particle size of 0.01 to 1 μm at a cumulative percentage of 50%.

28. The insulation material according to claim 27 , wherein the content of the dispersant is 0.001-8% by weight of the filler.

29. An insulation material having a dielectric constant of 10 or more comprising, as essential components, 1) at least one filler selected from the group consisting of barium titanate, strontium titanate, potassium titanate, magnesium titanate, lead titanate, titanium dioxide, barium zirconate, calcium zirconate and lead zirconate, 2) an insulating resin and 3) a dispersant containing a carboxylic group, wherein the dispersant containing a carboxylic group is a polymer containing a carboxylic group.

30. The insulation material according to claim 29 , wherein the insulating resin contains a high molecular weight component having a weight average molecular weight of 10000 or more and capable of forming a film and a thermosetting component.

31. A film bondable by thermocompression bonding comprising an insulation material according to claim 29 applied to a metal foil.

32. A film bondable by thermocompression bonding comprising an insulation material according to claim 29 applied to a plastic film carrier.

33. A film comprising an insulation material according to claim 29 and a conductive layer on both sides of the insulation material.

34. A circuit board comprising an insulation material according to claim 29 as an insulating layer of 3 to 100 μm thickness.

35. A circuit board comprising an insulation material according to claim 29 as a thermosetting insulating layer of 3 to 100 μm thickness.

36. A method of producing a circuit board, which comprises applying an insulation material according to claim 29 to a circuit board, thereby forming an insulating layer.

37. The insulation material according to claim 29 , wherein the at least one filler is selected from the group consisting of strontium titanate, potassium titanate, magnesium titanate, lead titanate, barium zirconate, calcium zirconate and lead zirconate.

38. The insulation material according to claim 29 , wherein the polymer containing a carboxylic group is a copolymer containing a carboxylic group.

39. The insulation material according to claim 29 , wherein the content of the dispersant is 0.001-8% by weight of the filler.

40. The insulation material according to claim 29 , wherein the filler has a dielectric constant of 50 or more, wherein said dispersant disperses the filler, and

wherein an extract of a cured product of the insulation material obtained by extraction with water at 120° C. for 20 hours using a pressure vessel has a pH of 6 or higher.

41. The insulation material according to claim 40 , which contains 30 to 90 parts by volume of the filler having a dielectric constant of 50 or more based on 100 parts by volume of the insulation material.

42. The insulation material according to claim 40 , wherein the insulating resin contains a high molecular weight component having a weight average molecular weight of 10000 or more and capable of forming a film and a thermosetting component.

43. A film bondable by thermocompression bonding comprising an insulation material according to claim 40 applied to a metal foil.

44. A film bondable by thermocompression bonding comprising an insulation material according to claim 40 applied to a plastic film carrier.

45. A film comprising an insulation material according to claim 40 and a conductive layer on both sides of the insulation material.

46. A circuit board comprising an insulation material according to claim 40 as an insulating layer of 3 to 100 μm thickness.

47. A circuit board comprising an insulation material according to claim 40 as a thermosetting insulating layer of 3 to 100 μm thickness.

48. A method of producing a circuit board, which comprises applying an insulation material according to claim 40 to a circuit board, thereby forming an insulating layer.

49. The insulation material according to claim 40 , wherein the content of the dispersant is 0.001-8% by weight of the filler.