Conductive composition, conductor and solid electrolytic capacitor using conductive composition
A conductive composition according to the present invention contains a conductive polymer (A) having a sulfonic acid group and/or a carboxyl group; and an alkali metal hydroxide and/or an alkaline earth metal hydroxide (B). In such a conductive composition, the amount of the hydroxide (B) is set at 0.2˜0.65 mol per 1 mol of a repeating unit that contains a sulfonic acid group and/or a carboxyl group in the conductive polymer (A).
1. A conductive composition, comprising:
a conductive polymer (A); and
a compound (D) which comprises a basic group and at least two hydroxy groups in the same molecule and whose melting point is 30° C. or higher, the compound (D) being selected from 2-amino-1,3-propanediol, tris(hydroxymethyl)aminomethane, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-ethyl-1,3-propanediol, 3[N-tris(hydroxymethyl)methylamino]-2-hydroxypropane-sulfonic acid, N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid, and combinations thereof;
wherein:
the conductive polymer (A) has a repeating unit of formula (1):
wherein:
one of R 1 to R 4 is a linear or branched alkoxy group having 1 to 4 carbon atoms;
one of R 1 to R 4 is a sulfonic acid group; and
two of R 1 to R 4 are hydrogen.
2. The conductive composition of claim 1 , wherein the conductive polymer (A) has an area ratio (X/Y) of 1.20 or greater, calculated by an analytical method comprising:
(I) preparing a test solution by dissolving the conductive polymer (A) at a solid concentration of 0.1% by mass in an eluent prepared to have a pH value of 10 or greater;
(II) obtaining a gel permeation chromatogram by measuring a molecular-weight distribution of the test solution using a gel permeation chromatograph of a polymer material analysis instrument;
(III) based on the chromatogram obtained in (II) above, converting a retention time to molecular weight (M) in terms of sodium polystyrene sulfonate;
(IV) determining an area (X) of a region where the molecular weight (M) in terms of sodium polystyrene sulfonate is 15000 Da or greater;
(V) determining an area (Y) of a region where the molecular weight (M) in terms of sodium polystyrene sulfonate is less than 15000 Da; and
(VI) calculating the area ratio (X/Y) of area (X) to area (Y).
3. A conductor comprising the conductive composition of claim 2 .
4. A solid electrolytic capacitor comprising the conductive composition of claim 2 .
5. The conductive composition of claim 2 , wherein the compound (D) is 2-amino-1,3-propanediol.
6. The conductive composition of claim 2 , wherein the compound (D) is tris(hydroxymethyl)aminomethane.
7. The conductive composition of claim 2 , wherein the compound (D) is 2-amino-2-methyl-1,3-propanediol.
8. The conductive composition of claim 2 , wherein the compound (D) is 2-amino-2-ethyl-1,3-propanediol.
9. The conductive composition of claim 2 , wherein the compound (D) is 3[N-tris(hydroxymethyl)methylamino]-2-hydroxypropane-sulfonic acid.
10. The conductive composition of claim 2 , wherein the compound (D) is N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid.
11. A conductor comprising the conductive composition of claim 1 .
12. A solid electrolytic capacitor comprising the conductive composition of claim 1 .
13. The conductive composition of claim 1 , wherein the compound (D) is 2-amino-1,3-propanediol.
14. The conductive composition of claim 1 , wherein the compound (D) is tris(hydroxymethyl)aminomethane.
15. The conductive composition of claim 1 , wherein the compound (D) is 2-amino-2-methyl-1,3-propanediol.
16. The conductive composition of claim 1 , wherein the compound (D) is 2-amino-2-ethyl-1,3-propanediol.
17. The conductive composition of claim 1 , wherein the compound (D) is 3[N-tris(hydroxymethyl)methylamino]-2-hydroxypropane-sulfonic acid.
18. The conductive composition of claim 1 , wherein the compound (D) is N-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acid.