Monofunctional amines as adhesion primers for conductive polymers
View Patent ↗The present invention relates to a process for producing an electrolytic capacitor wherein—a primer solution e) is applied to a capacitor body ( 1 ), followed by an application of a solution or dispersion a) comprising a conjugated polymer b) and a solvent or dispersant d), followed by an at least partial removal of the solvent or dispersant d) for the formation of a polymeric outer layer ( 5 ) that is formed onto the capacitor body ( 1 ), and wherein the primer solution e) comprises at least one monofunctional amine and at least one carboxylic acid.
1. A process for producing an electrolytic capacitor, the process comprising process steps i) and ii):
i) providing a capacitor body that comprises
an electrode body of an electrode material,
a dielectric which at least partially covers the surface of this electrode material, and
a solid electrolyte at least comprising an electrically conductive material which at least partially covers the dielectric surface,
ii) applying a primer solution e) to the capacitor body, followed by an application of a solution or dispersion a) comprising a conjugated polymer b) and a solvent or dispersant d), followed by an at least partial removal of the solvent or dispersant d) for the formation of a polymeric outer layer that is formed onto the capacitor body;
wherein the primer solution e) comprises at least one monofunctional amine and at least one carboxylic acid.
2. The process according to claim 1 , wherein the monofunctional amine is a primary, secondary or tertiary amine of formula (I)
wherein each R group may be identical or different and represents
a hydrogen,
a C 1 -C 300 -aliphatic or hetero aliphatic group,
a C 6 -C 18 , aromatic or hetero aromatic group, or
a C 7 -C 18 aralkyl or hetero aralkyl group,
wherein two R-groups may be linked to each other.
3. The process according to claim 2 , wherein each R group independently represents
a hydrogen,
a linear C 1 -C 18 -alkyl-group,
a branched C 3 -C 18 -alkyl-group,
a C 5 -C 18 -cycloalkyl-group,
a linear C 1 -C 18 -hydroxyalkyl-group with at least one OH-group,
a branched C 3 -C 18 -hydroxyalkyl-group with at least one OH-group,
a cyclic C 5 -C 18 -hydroxyalkyl-group with at least one OH-group,
a polyalkylenoxid-group of the formula —(CH 2 CH 2 O) n —OR′ or —(CH 2 CHCH 3 O) n —OR′, in which n is an integer from 2 to 100 and R′ represents H or a linear C 1 -C 10 -alkyl-group, a branched C 3 -C 10 -alkyl-group or a C 5 -C 10 -cycloalkyl-group,
a C 2 -C 18 -alkenyl-group,
a C 6 -C 18 -aryl-group, or
a C 7 -C 18 -aralkyl-group.
4. The process according to claim 1 , wherein the monofunctional amine is a primary amine.
5. The process according to claim 4 , wherein the monofunctional amine is selected from the group consisting of hexylamine, tert-octylamine, octylamine, di-octylamine, tri-octylamine and dodecylamine.
6. The process according to claim 1 , wherein the carboxylic acid is a monofunctional, a difunctional or a trifunctional carboxylic acid or a polyfunctional carboxylic acid, wherein the carboxylic acid may also comprise a functional group selected from the group consisting of a hydroxyl-group, an ether-group, a thiol-group or a thioether-group.
7. The process according to claim 6 , wherein the carboxylic acid is selected from the group consisting of acetic acid, hexanoic acid, adipic acid, succinic acid and trimesic acid.
8. The process according to claim 1 , wherein the molar ratio of the amine to the carboxylic acid groups of the carboxylic acid in the primer solution e) is in the range from 0.1:1 to 10:1.
9. The process according to claim 1 , wherein the concentration of the monofunctional amine in the primer solution e) that is applied in process step ii) is in the range from 0.01 to 10 mol/l and wherein the concentration of the carboxylic acid in the primer solution e) that is applied in process step ii) is in the range from 0.01 to 10 mol/l.
10. The process according to claim 1 , wherein the conjugated polymer b) is a cationic polymer and wherein solution or dispersion a) comprises a polymeric anion serving as a counter-ion for conjugated polymer.
11. The process according to claim 10 , wherein the polymeric anion is an anion of a polymeric carboxylic or sulfonic acid.
12. The process according to claim 1 , wherein in process step ii) the primer compound e) and the solution or dispersion a) are applied sequentially and repeatedly.
13. The process according to claim 1 , wherein the solution or dispersion a) comprises, as the conjugated polymer, an electrically conductive polymer selected from the group consisting of an optionally substituted polythiophene, an optionally polyaniline and an optionally substituted polypyrrole.
14. The process according to claim 1 , wherein the solution or dispersion a) comprises, as the conjugated polymer, poly(3,4-ethylenedioxythiophene), being present in the form of a poly(3,4-ethylenedioxythiophene)/polystyrenesulfonic acid-complex.