Anisotropic conductive sheet

• US 6,849,335 B2
• Filed: 08/08/2001
• Issued: 02/01/2005
• Est. Priority Date: 08/09/2000
• Status: Active Grant

• Current Assignee: ISC Incorporated (Svenska Cellulosa AB)
• Original Assignee: JSR Corporation
• Inventors: Inoue, Kazuo, Igarashi, Hisao, Setaka, Ryoji
• Primary Examiner(s): Kiliman, Leszek
• Application Number:
  US10/333,135
• Publication Number:
  US 20040009343A1
• Time in Patent Office: 1,273 Days
• Field of Search: 428/403, 428/407, 361/56, 361/58, 361/100, 361/115, 361/127, 361/212, 361/220
• US Class Current: 428/403
• CPC Class Codes: H01B 1/20 Conductive material dispersed in non-conductive organic material organic macromolecular compounds or compositions C08
• CPC Class Codes: H01R 13/2414 conductive elastomers
• CPC Class Codes: Y10T 428/254 Polymeric or resinous material
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2998 including synthetic resin or polymer
• CPC Class Codes: Y10T 428/32 Composite [nonstructural laminate] of inorganic material having metal-compound-containing layer and having defined magnetic layer

Abstract

Disclosed herein is an anisotropically conductive sheet capable of holding charge in its surfaces under an unpressurised state, and moving the charge held in the surface in a thickness-wise direction thereof in a state pressurised in the thickness-wise direction, thereby controlling the quantity of the charge at the surface.

This anisotropically conductive sheet comprises a sheet base composed of an elastomer and conductive particles exhibiting magnetism contained in the sheet base in a state oriented so as to arrange in rows in a thickness-wise direction of the sheet base, and dispersed in a plane direction thereof. Supposing that a volume resistivity in the thickness-wise direction under an unpressurised state is R₀, and a volume resistivity in the thickness-wise direction in a state pressurised under a pressure of 1 g/mm² in the thickness-wise direction is R₁, the volume resistivity R₁ is 1×10⁷ to 1×10¹² Ω·m, and a ratio (R₀/R₁) of the volume resistivity R₀ to the volume resistivity R₁ is 1×10¹ to 1×10⁴.

Claims

1. An anisotropically conductive sheet, comprising:

a sheet base comprising an elastomer; and

conductive particles exhibiting magnetism, said conductive particles being contained in the sheet base in a state oriented so as to arrange in rows in a thickness-wise direction of the sheet base, and dispersed in a plane direction of the base sheet,

wherein

supposing that a volume resistivity in the thickness-wise direction of said base sheet under an underpressurized state is R₀, and a volume resistivity in the thickness-wise direction in a state pressurized under a pressure of 1 g/mm² in the thickness-wise direction is R₁,

the volume resistivity R₁ is 1×

10⁷ to 1×

10¹² Ω

·

m, and

a ratio (R₀/R₁) of the volume resistivity R₀ to the volume resistivity R₁ is 1×

10¹ to 1×

10⁴.

2. The anisotropically conductive sheet according to claim 1, wherein the volume resistivity R₀ is 1×

10⁹ to 1×

10¹⁴ Ω

·

m.

3. The anisotropically conductive sheet according to claim 1, wherein a surface resistivity is 1×

10¹³ to 1×

10¹⁶ Ω

/□

.

4. The anisotropically conductive sheet according to claim 1, wherein a total area proportion occupied by a substance forming the conductive particles detected by electronic probe microanalysis in one surface of the sheet is 15 to 60%.

8. The anisotropically conductive sheet according to claim 1, wherein said elastomer is cross-linked.

9. The anisotropically conductive sheet according to claim 1, wherein said elastomer is at least one member selected from the group consisting of conjugated diene rubbers, a hydrogenated product of a conjugated diene rubber, block copolymer rubbers, a hydrogenated product of a block copolymer rubber, chloroprene rubber, urethane rubber, polyester rubber, epichlorhydrin rubber, silicone rubber, ethylene-propylene copolymer rubber, and ethylene-propylene-diene copolymer rubber.

10. The anisotropically conductive sheet according to claim 1, wherein said elastomer is silicone rubber.

11. The anisotropically conductive sheet according to claim 1, wherein said conductive particles comprise a ferrite represented by the formula

M¹O.Fe₂O₃,

wherein M¹ is at least one element selected from the group consisting of Mn, Fe, Ni, Cu, Zn, Mg, Co, and Li.

12. The anisotropically conductive sheet according to claim 1, wherein said conductive particles have a number average particle diameter of from 1 to 1000 μ

m.

13. The anisotropically conductive sheet according to claim 1, wherein said conductive particles have a number average particle diameter of from 1 to 20 μ

m.

14. The anisotropically conductive sheet according to claim 1, wherein said conductive particles have a particle diameter distribution (Dw/Dn) of 1 to 10.

15. The anisotropically conductive sheet according to claim 1, wherein said conductive particles have a water content of not more than 5%.

5. An anisotropically conductive sheet, comprising:

a sheet base comprising an elastomer; and

conductive particles exhibiting magnetism and a volume resistivity of 1×

10² to 1×

10⁷ Ω

·

m, said conductive particles being contained in the sheet base in a state oriented so as to arrange in rows in a thickness-wise direction of the sheet base, and dispersed in a plane direction of said base sheet.

6. The anisotropically conductive sheet according to claim 5, wherein the conductive particles comprise ferrite.

7. The anisotropically conductive sheet according to claim 5, wherein, a non-magnetic conductivity-imparting substance is contained in the sheet base.

16. The anisotropically conductive sheet according to claim 5, comprising a non-magnetic conductivity-imparting substance selected from the group consisting of a self-conductive substance, a hygroscopic conductive substance and mixtures thereof.

17. The anisotropically conductive sheet according to claim 5, comprising an aliphatic sulfonic acid salt.

18. The anisotropically conductive sheet according to claim 5, wherein said conductive particles comprise a ferrite represented by the formula

M¹O.Fe₂O₃,

wherein M¹ is at least one element selected from the group consisting of Mn, Fe, Ni, Cu, Zn, Mg, Co, and Li.

19. The anisotropically conductive sheet according to claim 5, wherein said conductive particles have a number average particle diameter of from 1 to 1000 μ

m.

20. The anisotropically conductive sheet according to claim 5, wherein said conductive particles have a number average particle diameter of from 1 to 20 μ

m.