Conductive composition and conductive film
Provided is a conductive composition that has a high conductivity and from which a coating can be formed easily. Also provided is a conductive film that has a high conductivity and in which electric resistance is less likely to increase even during expansion. A conductive composition is prepared by including an elastomer component, a fibrous carbon material having a graphite structure and a fiber diameter of not less than 30 nm, and a conductive carbon black having a structure. A conductive film formed from the conductive composition. The viscosity of the conductive composition formed into a coating with a solid content concentration of not less than 20% by mass, which is measured with a B-type viscometer with an H7 rotor under the conditions of a temperature of 25° C. and a rotation speed of 20 rpm, is not more than 200 Pa·s.
1. A conductive composition comprising:
an elastomer component;
a fibrous carbon material having a graphite structure and a fiber diameter of not less than 30 nm;
an organic solvent; and
a conductive carbon black having a structure, wherein
the fibrous carbon material is carbon nanotubes of which an intensity ratio (G/D ratio) of a peak (G band) appearing in the vicinity of 1580 cm −1 to a peak (D band) appearing in the vicinity of 1330 cm −1 of Raman spectrum is not less than 1.8, and
a viscosity measured with a B-type viscometer with an H7 rotor under conditions of a temperature of 25° C. and a rotation speed of 20 rpm is not more than 200 Pa·s, when a solid content concentration of the conductive composition is not less than 20% by mass.
2. The conductive composition according to claim 1 , further comprising a dispersant.
3. The conductive composition according to claim 1 used in screen printing or metal mask printing.
4. A conductive film formed from the conductive composition according to claim 1 .
5. The conductive film according to claim 4 formed by screen printing or metal mask printing.
6. The conductive film according to claim 4 formed on a surface of a substrate that is expandable and contractible, or bendable.
7. The conductive film according to claim 6 , wherein
the elastomer component in the conductive composition has a cross-linkable functional group;
the substrate is made of a polymer having a functional group; and
the conductive film is bonded to the substrate through chemical bonding between the cross-linkable functional group and the functional group.
8. The conductive film according to claim 4 , wherein the volume resistivity is not more than 0.5 Ω·cm when the conductive film is expanded in a uniaxial direction by 50%.
9. An electromagnetic shield formed of the conductive film according to claim 4 .
10. A transducer comprising:
a dielectric layer made of a polymer;
a plurality of electrodes arranged with the dielectric layer interposed therebetween; and
a wire connected to each of the electrodes, wherein
either or both of the electrodes and the wire are formed of the conductive film according to claim 4 .
11. A flexible wiring board comprising:
a substrate; and
a wire arranged on a surface of the substrate, wherein
at least part of the wire is formed of the conductive film according to claim 4 .
12. A conductive film formed from a conductive composition comprising:
an elastomer component;
a fibrous carbon material having a graphite structure and a fiber diameter of not less than 30 nm; and
a conductive carbon black having a structure, wherein
the fibrous carbon material is carbon nanotubes of which an intensity ratio (G/D ratio) of a peak (G band) appearing in the vicinity of 1580 cm −1 to a peak (D band) appearing in the vicinity of 1330 cm −1 of Raman spectrum is not less than 1.8; and
wherein the volume resistivity of the conductive film is not more than 0.5 Ω·cm when the conductive film is expanded in a uniaxial direction by 50%.
13. The conductive film according to claim 12 , wherein the conductive composition further comprises a dispersant.
14. The conductive film according to claim 12 formed by screen printing or metal mask printing.
15. The conductive film according to claim 12 formed on a surface of a substrate that is expandable and contractible, or bendable.
16. The conductive film according to claim 15 , wherein
the elastomer component in the conductive composition has a cross-linkable functional group;
the substrate is made of a polymer having a functional group; and
the conductive film is bonded to the substrate through chemical bonding between the cross-linkable functional group and the functional group.
17. An electromagnetic shield formed of the conductive film according to claim 12 .
18. A transducer comprising:
a dielectric layer made of a polymer;
a plurality of electrodes arranged with the dielectric layer interposed therebetween; and
a wire connected to each of the electrodes, wherein either or both of the electrodes and the wire are formed of the conductive film according to claim 12 .
19. A flexible wiring board comprising:
a substrate; and
a wire arranged on a surface of the substrate, wherein
at least part of the wire is formed of the conductive film according to claim 12 .