U.S. patent application number 10/567555 was filed with the patent office on 2006-10-05 for conductive polymer and solid electrolytic capacitor using same.
This patent application is currently assigned to Tayca Corporation. Invention is credited to Ryosuke Sugihara, Masaaki Tozawa.
Application Number | 20060223976 10/567555 |
Document ID | / |
Family ID | 34131638 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060223976 |
Kind Code |
A1 |
Tozawa; Masaaki ; et
al. |
October 5, 2006 |
Conductive polymer and solid electrolytic capacitor using same
Abstract
The conductive polymer of the present invention is prepared by
means of oxidation polymerization. On the matrix of the conductive
polymer, at least one organic sulfonate formed by an anion of an
organic sulfonic acid and a cation of other than transition metals
is coated. Alternatively, in the matrix of the conductive polymer,
at least one organic sulfonate formed by an anion of an organic
sulfonic acid and a cation of other than transition metals is
included. The conductive polymer of the present invention is
excellent in the conductivity, heat resistance and moisture
resistance. By using it as a solid electrolyte, a reliable solid
electrolytic capacitor can be prepared which is unlikely to
decrease the properties when being kept in a hot and humid
condition.
Inventors: |
Tozawa; Masaaki; (Osaka,
JP) ; Sugihara; Ryosuke; (Osaka, JP) |
Correspondence
Address: |
WESTERMAN, HATTORI, DANIELS & ADRIAN, LLP
1250 CONNECTICUT AVENUE, NW
SUITE 700
WASHINGTON
DC
20036
US
|
Assignee: |
Tayca Corporation
3-47, Funamachi 1-chome, Taisho-ku Osaka
Osaka-shi
JP
551-0022
|
Family ID: |
34131638 |
Appl. No.: |
10/567555 |
Filed: |
August 6, 2004 |
PCT Filed: |
August 6, 2004 |
PCT NO: |
PCT/JP04/11676 |
371 Date: |
February 8, 2006 |
Current U.S.
Class: |
528/373 |
Current CPC
Class: |
C08K 5/42 20130101; C08L
65/00 20130101; Y10T 428/2982 20150115; C08K 5/42 20130101; H01G
9/028 20130101; C08L 65/00 20130101 |
Class at
Publication: |
528/373 |
International
Class: |
C08G 75/00 20060101
C08G075/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 11, 2003 |
JP |
2003-291220 |
Claims
1. (canceled)
2. A conductive polymer according to claim 12, wherein a monomer
for the conductive polymer is at least one selected from the group
consisting of thiophene, pyrrole and the derivatives thereof.
3. A conductive polymer according to claim 12, wherein the
conductive polymer obtained by the oxidation polymerization uses an
organic sulfonic acid as a dopant.
4. A conductive polymer according to claim 12, wherein the cation
of the organic sulfonate is a metal cation other than a transition
metal.
5. A conductive polymer according to claim 12, wherein the cation
of the organic sulfonate has a backbone having at least one
selected from the group consisting of five-membered heterocyclic
ring, benzene ring, naphthalene ring, tetralin ring and anthracene
ring, and at least one selected from the group consisting of NH
group and NH.sub.2.
6. A conductive polymer according to claim 12, wherein the anion of
the organic sulfonate has a backbone having at least one selected
from the group consisting of benzene ring, naphthalene ring,
tetralin ring and anthracene ring.
7. A conductive polymer according to claim 12, wherein the anion of
the organic sulfonate has a backbone having at least one selected
from the group consisting of benzene ring, naphthalene ring,
tetralin ring and anthracene ring, wherein the backbone is
connected to at least one functional group selected from the group
consisting of alkyl group having a carbon number of 1 to 12,
hydroxyl group, alkoxy carbonyl group having a carbon number of 2
to 10, alkoxyl group and aldehyde group having a carbon number of 1
to 10, and at least one sulfonic acid group.
8. A conductive polymer according to claim 12, wherein the anion of
the organic sulfonate has a backbone having at least one selected
from the group consisting of benzene ring, naphthalene ring,
tetralin ring and anthracene ring, wherein the backbone is
connected to at least one functional group selected from the group
consisting of alkyl group having a carbon number of 1 to 12,
hydroxyl group, alkoxy carbonyl group having a carbon number of 2
to 10, alkoxyl group and aldehyde group having a carbon number of 1
to 10, and at least one sulfonic acid group, wherein protons of the
sulfonic acid are partially replaced with fluorine.
9. A conductive polymer according to claim 12, wherein the organic
sulfonate is a mixture of a first organic sulfonate comprising an
anion having a backbone having at least one selected from the group
consisting of benzene ring, naphthalene ring, tetralin ring and
anthracene ring, and hydroxyl group and at least one sulfonic acid;
and a second organic sulfonate comprising an anion having a
backbone having at least one selected from the group consisting of
benzene ring, naphthalene ring, tetralin ring and anthracene ring,
an aldehyde group having a carbon number of 1 to 10, and at least
one sulfonic acid group.
10. A conductive polymer according to claim 12, wherein the
oxidation polymerization is chemical oxidation polymerization,
wherein the conductive polymer obtained by the chemical oxidation
polymerization comprises a transition metal salt of the organic
sulfonic acid serving as a dopant as well as serving as an
oxidant.
11. A solid electrolytic capacitor, wherein the conductive polymer
according to claim 1 is used as a solid electrolyte.
12. A conductive polymer, comprising a matrix of the conductive
polymer and an organic sulfonate coated on or included in the
conductive polymer, wherein the conductive polymer is obtained by
oxidation polymerization, wherein the organic sulfonate is formed
by an anion of an organic sulfonic acid and a cation other than a
transition metal.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a conductive polymer and a
solid electrolytic capacitor using the conductive polymer as a
solid electrolyte.
BACKGROUND OF THE INVENTION
[0002] Conductive polymers have a high conductivity, which are used
as solid electrolytes of a solid electrolytic capacitor such as
aluminum capacitors and tantalum capacitors.
[0003] As a conductive polymer used therefor, ones are often used
which are synthesized by subjecting thiophenes or the derivatives
thereof to chemical oxidation polymerization or electrolysis
oxidation polymerization.
[0004] In carrying out the chemical oxidation polymerization, an
organic sulfonic acid is generally used as a dopant, and ammonium
persulfate, hydrogen peroxide, and transition metal salts are
generally used as an oxidant. Generally, in case where a process of
a chemical oxidation polymerization is used to synthesize a
conductive polymer, especially by using transition metal salts as
an oxidant, it needs to remove unnecessary components by
washing.
[0005] In such a case, a washing liquid such as an alcohol, water
or the combination thereof can be generally used. However, such a
washing process causes the dopant to be de-doped, decreasing the
electric conductivity of the conductive polymer. In order to avoid
the de-doping, it has been proposed to wash it with either or both
of an aqueous solution and an ethanol solution, as previously
prepared, including an organic sulfonic acid as a dopant.
[0006] However, in such a case, it is necessary to further wash it
with water or an alcohol in order to avoid an excessive amount of
an organic sulfonic acid from remaining. A conductive polymer that
an excessive amount of an organic sulfonic acid remains is
characterized in being smaller in the initial resistance and less
changeable in the electric conductivity when it is kept in a hot
condition for an extended period, than ones that an excessive
organic sulfonic acid is removed by washing with water or an
alcohol at the final stage. However, the conductive polymer in
which an excessive amount of an organic sulfonic acid remains is
apt to generate SO.sub.3 that is toxic when it is kept in hot
condition than the conductive polymer which is washed to remove an
excessive amount of an organic sulfonic acid, because the excessive
(free) organic sulfonic acid is apt to be decomposed in a hot
condition. Also, when a capacitor using a conductive polymer
including an excessive amount of an organic sulfonic acid is used
as a cathode layer, the properties thereof could be instable. (See
Japanese Laid-open Patent Publication No. 10-12498)
SUMMARY OF THE INVENTION
[0007] In view of the objectives of the prior art, the present
invention provides a conductive polymer excellent in conductivity,
heat resistance and moisture resistance, which is less changeable
in the electric conductivity when being kept in a hot and humid
condition, so as to avoid the decomposition in a hot condition.
Also, the objective of the present invention is to use the
conductive polymer as a solid electrolyte, to provide a reliable
solid electrolytic capacitor which less decreases the properties in
a hot and humid condition.
[0008] The objectives of the present invention can be achieved by
providing a conductive polymer including at least one organic
sulfonate having an anion of an organic sulfonic acid, that is the
same or different from the organic sulfonic acid incorporated in
the conductive polymer as a dopant, and a cation other than
transition metals.
[0009] That is, on the matrix of the conductive polymer prepared by
means of the oxidation polymerization of the present invention, at
least one Organic sulfonate having an anion of an organic sulfonic
acid and a cation other than transition metals is coated.
Alternatively, in the matrix of the conductive polymer prepared by
means of the oxidation polymerization of the present invention, at
least one Organic sulfonate having an anion of an organic sulfonic
acid and a cation other than transition metals is included. The
present invention also relates to a solid electrolytic capacitor
using the conductive polymer as a solid electrolyte.
[0010] The conductive polymer of the present invention is excellent
in conductivity, heat resistance, and moisture resistance, which
less decreases the electric conductivity when being kept in a hot
and humid condition and to decompose in a hot condition. Also, the
solid electrolyte capacitor of the present invention by using the
conductive polymer as a solid electrolyte is reliable because it
has the properties less decreased when being kept in a hot and
humid condition.
[0011] In the present invention, the term "matrix" of the
conductive polymer denotes the whole structure of the conductive
polymer where its surface is not always smooth. When washing step
is applied to the conductive polymer after it is synthesized by
means of oxidation polymerization, an oxidant, excessive dopant,
unreacted monomer and oligomers incorporated in the conductive
polymer can be washed out, and the dopant doped therein can be
partly removed, so that the surface is not always made smooth.
[0012] The best mode of the present invention is hereinafter
described.
[0013] First, the organic sulfonate used in the present invention
is described. The organic sulfonate is formed by an anion of an
organic sulfonic acid and a cation other than a transition
metal.
[0014] In the organic sulfonate, the examples of the organic
sulfonic acid as the anion component can include, as the backbone,
at least one selected from the group consisting of benzene ring,
naphthalene ring, tetralin ring and anthracene ring. Examples
thereof include aromatic sulfonic acids such as benzene sulfonic
acid, pentafluorobenzene sulfonic acid, benzene disulfonic acid,
para-toluene sulfonic acid, fluoro para-toluene sulfonic acid,
ethylbenzene sulfonic acid, dodecylbenzene sulfonic acid,
naphthalene sulfonic acid, naphthalene disulfonic acid,
methylnaphthalene sulfonic acid, ethylnaphthalene sulfonic acid,
butylnaphthalene sulfonic acid, dinonylnaphthalene sulfonic acid,
anthraquinone sulfonic acid, anthraquinone disulfonic acid,
anthracene sulfonic acid, methoxybenzene sulfonic acid,
ethoxybenzene sulfonic acid, butoxybenzene sulfonic acid,
methoxynaphthalene sulfonic acid, ethoxynaphthalene sulfonic acid,
butoxynaphthalene sulfonic acid, tetralin sulfonic acid,
butyltetralin sulfonic acid, sulfobenzene carboxylic acid
methylester, sulfobenzene carboxylic acid dimethylester,
sulfobenzene carboxylic acid butylester, sulfobenzene dibutylester,
sulfonaphthalene carboxylic acid methylester, sulfonaphthalene
carboxylic acid dimethylester, sulfonaphthalene carboxylic acid
butylester, sulfonaphthalene sulfonic acid dibutylester, phenol
sulfonic acid, cresol sulfonic acid, sulfophthalic acid,
sulfoisophthalic acid, sulfosalicyclic acid, sulfonaphthoic acid,
hydroxysulfonaphthoic acid, naphthol sulfonic acid, benzaldehyde
sulfonic acid, benzaldehyde disulfonic acid, and naphtoaldehyde
sulfonic acid.
[0015] As the organic sulfonic acid, ones having a backbone of at
least one selected from the group consisting of benzene ring,
naphthalene ring, tetralin ring and anthracene ring; at least one
functional group selected from the group consisting of alkyl group
having a carbon number of 1 to 12, and hydroxy group, alkoxy
carbonyl group having a carbon number of 2 to 10, and alkoxy group
and aldehyde group having a carbon number of 1 to 10; and at least
one sulfonic acid group can be used. Examples thereof can include
methoxybenzene sulfonic acid, ethoxybenzene sulfonic acid,
butoxybenzene sulfonic acid, methoxynaphthalene sulfonic acid,
ethoxynaphthalene sulfonic acid, butoxynaphthalene sulfonic acid,
phenol sulfonic acid, cresol sulfonic acid, sulfophthalic acid,
sulfoisophthalic acid, sulfosalicyclic acid, sulfonaphthoic acid,
hydroxysulfonaphthoic acid, naphthol sulfonic acid, benzaldehyde
sulfonic acid, benzaldehyde disulfonic acid, naphtoaldehyde
sulfonic acid, dihydroxy anthracene sulfonic acid, sulfobenzene
carboxylic acid methylester, sulfobenzene carboxylic acid
dimethylester, sulfobenzene carboxylic acid butylester,
sulfobenzene carboxylic acid dibutylester, sulfonaphthalene
carboxylic acid methylester, sulfonaphthalene carboxylic acid
dimethylester, sulfonaphthalene carboxylic acid butylester, and
sulfonaphthalene sulfonic acid dibutylester.
[0016] As the cation of the organic sulfonate of the present
invention other than transition metals, examples can include a
metal other than a transition metal and an organic cation.
[0017] As the cation other than the transition metal, sodium ion,
potassium ion, magnesium ion, calcium ion, and aluminum ion can be
included. Among these metal cations, ones with divalence or more,
rather than monovalence, including calcium ion and aluminum ion can
be generally used in view of the heat resistance and moisture
resistance.
[0018] As the organic cations, ones that a basic organic compound
such as amino ethanol, diamino propane, imidazolium, amino
anthraquinone, amino azotoluene, naphthyl amine and adenine is
cationized can be included. Among them, ones that a basic compound
is cationized to have a backbone of at least one selected from the
group consisting of five-membered heterocyclic ring, benzene ring,
naphthalene ring, tetralin ring and anthraquinone ring, and at
least one selected from the group consisting of NH group and
NH.sub.2 group, such as imidazole, amino anthraquinone, amino
azotoluene, naphthyl amine, adenine, can be used in view of the
heat resistance and moisture resistance.
[0019] The organic sulfonate used in the present invention can be
formed by a general method for reacting an organic acid with a
metal salt or a basic organic compound. That is, the organic
sulfonic acid as listed is reacted with a metal salt other than the
transition metals, or a basic organic compound, so as to form a
usable organic sulfonate. For example, calcium naphtholsulfonate or
calcium phenolsulfonate can be obtained from naphtholsulfonic acid
or phenolsulfonic acid, which is diluted with pure water, and then,
calcium hydroxide is added to be reacted with the naphthol sulfonic
acid or the phenol sulfonic acid. Upon the reaction, a filter
filtration process can be applied for purification, if
necessary.
[0020] Next, the conductive polymer obtained by the oxidation
polymerization, which is used in the present invention, will be
described.
[0021] As the monomer for synthesizing the conductive polymer, it
is possible to use thiophene, pyrrole and the derivatives
thereof.
[0022] In synthesizing the conductive polymer by means of the
oxidation polymerization, the monomer for synthesizing the
conductive polymer, such as pyrrole, thiophene or the derivatives
thereof, is polymerized by means of a chemical oxidation
polymerization or electrolysis oxidation polymerization method by
using an organic sulfonic acid such as paratoluene sulfonic acid as
a dopant, so as to obtain a conductive polymer.
[0023] Next, to the surface of the obtained conductive polymer, a
treatment is applied by using at least one organic sulfonate made
of an anion of the organic sulfonic acid and a cation other than
transition metals, so as to form a conductive polymer treated with
the Organic sulfonate of the present invention. (The conductive
polymer can be referred to as "an organic sulfonate treated
conductive polymer." Here, the organic sulfonate treatment closely
relates to the washing process during synthesizing the conductive
polymer, so there are different treatment processes between the
chemical oxidation polymerization and the electrolysis oxidation
polymerization. Each of the cases is described in detail.
[0024] In case of synthesizing the conductive polymer by means of
the chemical oxidation polymerization, an organic sulfonic acid
such as alkoxybenzene sulfonic acid, alkoxynaphthalene sulfonic
acid and alkoxytetralin sulfonic acid is changed into a transition
metal salt such as a ferric salt or a cupric salt. The organic
sulfonate and a monomer, that is, a raw material of the polymer,
are previously and respectively solved into an organic solvent to
have a predetermined concentration, and then, the solutions are
mixed together, and then, the monomer is polymerized. By washing
and drying, a conductive polymer can be obtained. The transition
metal of the organic sulfonate can be served as an oxidation
polymerization agent for the monomer, and the rest, that is, the
organic sulfonic acid component, can be included in the polymer
matrix, serving as a dopant. As the organic solvent used for
synthesizing the conductive polymer, examples thereof can include
methanol, ethanol, n-propanol, and n-butanol. In washing, an
organic sulfonic acid such as methoxy benzene sulfonic acid in an
organic solution or pure water solution to have a concentration of
several % by mass can be used. After the washing, the same organic
solvent or pure water can be used for removing the excessive amount
of the organic sulfonic acid (here, methoxybenzene sulfonic acid).
Thereafter, the conductive polymer is immersed into an organic
sulfonate solution, such as calcium phenolsulfonate aqueous
solution or phenol sulfonic acid naphthyl amine salt ethanol
solution, having a concentration of several % by mass for several
tens of minutes, followed by being taken out and dried.
[0025] In case of synthesizing a conductive polymer by means of the
electrolysis oxidation polymerization, an organic sulfonic acid
such as butylnaphthalene sulfonic acid or the salt thereof (sodium
salt, potassium salt, etc.), and a monomer are solved into a
solvent, which is then subjected to polymerization under a
condition of a constant voltage or constant current, so as to
synthesize a conductive polymer. As the solvent used for the
synthesis of the conductive polymer, examples thereof can include
water, methanol, ethanol, n-propanol, and n-butanol. In washing, an
organic sulfonic acid, such as a phenol sulfonic acid solution
having a concentration of several % by mass using one of the
solvent as listed above, can be used, and after the washing, an
excessive amount of the organic sulfonic acid (here, phenol
sulfonic acid) can be removed by using pure water or the solvent.
Thereafter, the conductive polymer is immersed into an organic
sulfonate solution (for example, a calcium phenolsulfonate aqueous
solution or a phenol sulfonic acid amino azotoluene salt ethanol
solution) having several % by mass for several tens of minutes,
followed by being taken out and dried.
[0026] The organic sulfonate treated conductive polymer of the
present invention, as polymerized and treated by the organic
sulfonate, is excellent in conductivity, heat resistance and
moisture resistance, is less in decreasing the electric
conductivity when being kept in a hot and humid condition, and is
less in being decomposed in a hot condition. Thus, it is reliable
so that it can be useful in cathode layers of a capacitor,
electrodes of a battery, electrical conductive agent for an
antistatic sheet and so on. Especially, the solid electrolytic
capacitor using the organic sulfonate treated conductive polymer of
the present invention as a solid electrolyte is excellent in
electric properties.
EXAMPLES
[0027] Based on Examples, the present invention is described more
in detail. The present invention, however, is not limited to the
Examples. Before describing the Examples, Production Examples 1 to
15 are described for explaining the preparation of the Organic
sulfonate solution for treating the conductive polymer obtained by
the oxidation polymerization method. The symbol "%" used for
showing the concentration of the solutions is based on mass %
unless other basis is mentioned.
Production Example 1
[0028] To 1000 g of 10% paratoluene sulfonic acid aqueous solution
stirred at room temperature, 2 mol of hydroxide sodium was added to
adjust it into pH6, approximately, so as to obtain a sodium
paratoluenesulfonate aqueous solution.
Production Example 2
[0029] To 1000 g of 5% paratoluene sulfonic acid aqueous solution
stirred at room temperature, 30 g of calcium hydroxide was added.
The stirring was continued while measuring the pH value. At the
time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a calcium paratoluenesulfonate aqueous
solution.
Production Example 3
[0030] To 1000 g of 5% phenol sulfonic acid aqueous solution
stirred at room temperature, 25 g of magnesium hydroxide was added.
The stirring was continued while measuring the pH value. At the
time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a magnesium phenolsulfonate aqueous
solution.
Production Example 4
[0031] To 1000 g of 5% phenol sulfonic acid aqueous solution
stirred at room temperature, 30 g of calcium hydroxide was added.
The stirring was continued while measuring the pH value. At the
time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a calcium phenolsulfonate aqueous
solution.
Production Example 5
[0032] To 1000 g of 5% pentafluorobenzene sulfonic acid aqueous
solution stirred at room temperature, 30 g of calcium hydroxide was
added. The stirring was continued while measuring the pH value. At
the time when the pH value reached 6, approximately, filtration was
done by using a 0.4% m glass filter to remove the insoluble
components, so as to obtain a calcium pentafluorobenzenesulfonate
aqueous solution.
Production Example 6
[0033] To 1000 g of 5% sulfosalicyclic acid aqueous solution
stirred at room temperature, 30 g of calcium hydroxide was added.
The stirring was continued while measuring the pH value. At the
time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a calcium sulfosalicylate aqueous
solution.
Production Example 7
[0034] To 1000 ml of 10% aluminum sulfate aqueous solution, 2N
sodium hydroxide aqueous solution was added to adjust the pH value
into 7.6. The precipitate as generated was collected by means of
filtration by using a 4 .mu.m glass filter, followed by stirring it
for a period of 10 minutes in order to disperse it into 1000 ml of
pure water. Further, the step for collecting the precipitate was
repeated for three times by using a 0.4 .mu.m glass filter,
followed by dispersing the precipitate into 800 ml of pure water.
There, 281 g of phenol sulfonic acid was added, and after 15 hours
of stirring at room temperature, insoluble elements were removed by
means of filtration by using a 0.4 .mu.m glass filter so as to
obtain an aluminum phenolsulfonate aqueous solution.
Production Example 8
[0035] To 1000 g of 2% phenol sulfonic acid ethanol solution, 2%
amino azotoluene ethanol solution, equimolal to the phenol sulfonic
acid component, was added in drops so as to prepare a phenol
sulfonic acid amino azotoluene solution.
Production Example 9
[0036] To 1000 g of phenol sulfonic acid aqueous solution stirred
at room temperature, 10% imidazole aqueous solution was added in
drops to adjust the pH value into about 6, approximately, so as to
prepare a phenol sulfonic acid imidazole solution.
Production Example 10
[0037] To 1000 g of 10% methoxybenzene sulfonic acid aqueous
solution stirred at room temperature, 30 g of calcium hydroxide was
added. The stirring was continued while measuring the pH value. At
the time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a calcium methoxybenzenesulfonate
aqueous solution.
Production Example 11
[0038] To 1000 g of 5% naphthol sulfonic acid aqueous solution
stirred at room temperature, 30 g of calcium hydroxide was added.
The stirring was continued while measuring the pH value. At the
time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a calcium naphtholsulfonate aqueous
solution.
Production Example 12
[0039] To 1000 g of 10% catechol sulfonic acid aqueous solution
stirred at room temperature, 30 g of calcium hydroxide was added.
The stirring was continued while measuring the pH value. At the
time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a calcium catecholsulfonate aqueous
solution.
Production Example 13
[0040] To 1000 g of 10% cresol sulfonic acid aqueous solution
stirred at room temperature, 30 g of calcium hydroxide was added.
The stirring was continued while measuring the pH value. At the
time when the pH value reached 6, approximately, filtration was
done by using a 0.4 .mu.m glass filter to remove the insoluble
components, so as to obtain a calcium cresolsulfonate aqueous
solution.
Production Example 14
[0041] To 1000 g of 10% sulfophthalic acid aqueous solution stirred
at room temperature, 30 g of calcium hydroxide was added. The
stirring was continued while measuring the pH value. At the time
when the pH value reached 6, approximately, filtration was done by
using a 0.4 .mu.m glass filter to remove the insoluble components,
so as to obtain a calcium sulfophthalate aqueous solution.
Production Example 15
[0042] To 1000 g of 10% dodecylphenol sulfonic acid solution
(ethanol 50% aqueous solution) stirred at room temperature, 30 g of
calcium hydroxide was added. The stirring was continued while
measuring the pH value. At the time when the pH value reached 6,
approximately, filtration was done by using a 0.4 .mu.m glass
filter to remove the insoluble components, so as to obtain a
calcium dodecylphenolsulfonate aqueous solution.
[0043] Next, by means of chemical oxidation polymerization,
polyethylene dioxythiophene was prepared. Thereby obtained
polyethylene dioxythiophene was applied to the treatment by the
Organic sulfonate solution as prepared in accordance with
Production Examples 1 to 11, so as to prepare Examples 1 to 11.
With respect to the polyethylene dioxythiophene prepared in the
same manner as the chemical oxidation polymerization as explained
above, Comparative Example 1 was prepared without applying the
treatment by the organic sulfonate solution. Also, with respect to
the polyethylene dioxythiophene prepared in the same manner as the
chemical oxidation polymerization as explained above, Comparative
Examples 2 to 5 were prepared by replacing the treatment by the
organic sulfonates of Examples 1 to 11 with the treatment by the
organic sulfonic acid solutions.
Examples 1 to 11
[0044] First, as explained below, polyethylene dioxythiophene was
prepared by means of chemical oxidation polymerization.
[0045] Ferric paratoluenesulfonate was solved into n-butanol to
have a concentration of 0.5 mol/l. Sufficient sets of the same
solution were prepared for Examples 1 to 11. To each of the
solutions, 3,4-ethylene dioxythiophene was added and fully stirred
to have a concentration of 0.5 mol/l, and using the ferric
sulfonate as an oxidant, the oxidation polymerization of
3,4-ethylene dioxythiophene was initiated, and immediately
thereafter, they were separately dropped on a ceramic plate having
a size of 3 cm.times.5 cm at an amount of 180 u 1.
[0046] They were polymerized under the condition at a temperature
of 25.degree. C. and at a relative humidity (hereinafter, it is
referred to as "humidity" for simplification) of 60% for a period
of 12 hours, so as to form a film of polyethylene dioxythiophene
formed on the ceramic plate. The polyethylene dioxythiophene formed
on the ceramic plate was washed by immersing it into 2% paratoluene
sulfonic acid aqueous solution for a period of 60 minutes, followed
by immersing it into ethanol for a period of 30 minutes, so as to
remove the excessive amount of paratoluene sulfonic acid.
Thereafter, the sulfonic acid solution as prepared by Production
Examples 1 to 11 was adjusted in concentration into 2% organic
sulfonate solution. To each of the organic sulfonates solution, the
ceramic plate forming the polyethylene dioxythiophene was immersed,
and after 5 minutes, it was taken out and dried at a temperature of
50.degree. C. for a period of 30 minutes, followed by drying it at
a temperature of 150.degree. C. for a period of 40 minutes, so as
to complete the organic sulfonate treatment of the polyethylene
dioxythiophene to obtain the samples of Examples 1 to 11.
Comparative Example 1
[0047] Unlike Example 1, the polyethylene dioxythiophene obtained
by means of chemical oxidation polymerization in the same manner as
Example 1 was not subjected to the organic sulfonate treatment of
Example 1, or used as it is, so as to obtain Comparative Example
1.
Comparative Examples 2 to 5
[0048] The polyethylene dioxythiophene by means of chemical
oxidation polymerization as prepared in the same manner as Example
1 was treated by 2% paratoluene sulfonic acid aqueous solution so
as to prepare Comparative Example 2; was treated by 2% paratoluene
sulfonic acid aqueous solution ethanol solution so as to prepare
Comparative Example 3; was treated by 2% phenol sulfonic acid
aqueous solution so as to prepare Comparative Example 4; and was
treated by 2% phenol sulfonic acid ethanol solution so as to
prepare Comparative Example 5. That is, these Comparative Examples
2 to 5 were prepared by replacing the organic sulfonate solution
treatment of Examples 1 to 11 with the organic sulfonic acid
solution treatment. Except for such replacement of the treatment,
the method for the treatment is the same as Examples 1 to 11.
Test Example 1
[0049] Examples 1 to 11 in which the polyethylene dioxythiophene
formed on the ceramic plate are subjected to the organic sulfonate
treatment, Comparative Example 1 in which the organic sulfonate
treatment was not applied, and Comparative Examples 2 to 5 in which
the organic sulfonic acid treatment was applied, were used. The
polyethylene dioxythiophene formed on the ceramic plate was
subjected to a load of 1.5 tons (t), which condition was kept for a
period of 5 minutes to equalize the film thickness. Then, the
electric conductivity of the polyethylene dioxythiophene was
measured at room temperature (about 25.degree. C.) in accordance
with JIS K 7194 by means of four probes type electric conductivity
measuring device (MCP-T600 manufactured by Mitsubishi Chemical
Corporation). The results and the components used for the treatment
are summarized in Table 1.
Test Example 2
Storage Test in a Hot Condition
[0050] The polyethylene dioxythiophenes formed on the ceramic
plates of Examples 1 to 11 and Comparative Examples 1 to 5, whose
electric conductivity were measured in Test Example 1, were placed
into a temperature controlled bath kept at a temperature of
130.degree. C. After 120 hours of storage, the plates were taken
out, and the electric conductivity of the polyethylene
dioxythiophene was measured in the same manner as Test Example 1,
to research the decrease rate of the electric conductivity during
storage at a hot condition. The results are summarized in Table 2.
The decrease rate of the electric conductivity was shown by
percentage (%) calculated by subtracting the initial electric
conductivity (electric conductivity before the storage at a hot
condition, that is, the electric conductivity measured by Test
Example 1) from the electric conductivity after the storage, which
is then divided by the initial electric conductivity. The formula
for calculating the decrease rate of the electric conductivity was
shown below. [Decrease Rate of Electric Conductivity (%)]=[(Initial
Electric Conductivity)-(Electric Conductivity after
Storage)]/(Initial Electric Conductivity).times.100
Test Example 3
Storage Test in a Hot and Humid Condition
[0051] Except for keeping it in a temperature controlled bath
maintained at a temperature of 85.degree. C. and at a humidity of
85% for a period of 300 hours, the same procedure was applied as
Test Example 2, in order to measure the decrease rate of the
electric conductivity. The results are summarized in Table 3.
TABLE-US-00001 TABLE 1 Electric Name of the components of the
Conductivity treatment liquid (S/cm) Example 1 Sodium
paratoluenesulfonate 94 Example 2 Calcium paratoluenesulfonate 98
Example 3 Magnesium phenolsulfonate 105 Example 4 Calcium
phenolsulfonate 102 Example 5 Calcium pentafluorobenzenesulfonate
116 Example 6 Calcium sulfosalicylate 99 Example 7 Aluminum
phenolsulfonate 138 Example 8 Phenol sulfonic acid amino 118
azotoluene Example 9 Phenol sulfonic acid imidazole 115 Example 10
Calcium methoxybenzenesulfonate 108 Example 11 Calcium
naphtholsulfonate 98 Comparative No treatment 80 Example 1
Comparative Paratoluene sulfonic acid 150 Example 2 Comparative
Paratoluene sulfonic acid 145 Example 3 Comparative Phenol sulfonic
acid 140 Example 4 Comparative Phenol sulfonic acid 140 Example
5
[0052] TABLE-US-00002 TABLE 2 Decrease Rate of the Electric
Conductivity (%) (Storage at 130.degree. C. for 120 hours) Example
1 40 Example 2 36 Example 3 27 Example 4 17 Example 5 27 Example 6
25 Example 7 18 Example 8 23 Example 9 22 Example 10 31 Example 11
28 Comparative 90 Example 1 Comparative 54 Example 2 Comparative 54
Example 3 Comparative 49 Example 4 Comparative 48 Example 5
[0053] TABLE-US-00003 TABLE 3 Decrease Rate of the Electric
Conductivity (%) (Storage at 85.degree. C. at a humidity of 85% for
300 hours) Example 1 44 Example 2 40 Example 3 29 Example 4 25
Example 5 35 Example 6 33 Example 7 22 Example 8 28 Example 9 30
Example 10 28 Example 11 30 Comparative 62 Example 1 Comparative 48
Example 2 Comparative 49 Example 3 Comparative 49 Example 4
Comparative 50 Example 5
[0054] As shown in Table 1, the organic sulfonate treated
polyethylene dioxythiophenes of Examples 1 to 11, that is, the
polyethylene dioxythiophene obtained by means of oxidation
polymerization which is then washed and treated by an Organic
sulfonate solution (In case of this organic sulfonate treated
polyethylene dioxythiophene, the organic sulfonate is coated on the
matrix of the polyethylene dioxythiophene obtained by the oxidation
polymerization, or the organic sulfonate is included in the matrix
of the polyethylene dioxythiophene obtained by the oxidation
polymerization, but for simplification, the polyethylene
dioxythiophene in such a state is referred to as the "polyethylene
dioxythiophene in accordance with Example."), showed a higher
electric conductivity than the polyethylene dioxythiophene in
accordance with Comparative Example 1 which was not treated by the
organic sulfonate solution. It should be noted that in Test Example
1, the organic sulfonate treated polyethylene dioxythiophenes of
Examples 1 to 11 showed a lower electric conductivity than the
polyethylene dioxythiophene of Comparative Examples 2 to 5, that
is, the polyethylene dioxythiophene obtained by the oxidation
polymerization followed by being washed and treated by the organic
sulfonic acid solution. However, the decrease rate of the electric
conductivity of the polyethylene dioxythiophenes of Comparative
Examples 2 to 5 were more than the polyethylene dioxythiophenes of
Examples 1 to 11, when they were kept in a hot condition or in a
hot and humid condition as shown in Test Examples 2 to 3. That is,
as shown in Tables 2 and 3, the polyethylene dioxythiophenes of
Examples 1 to 11 less decreased the electric conductivity when they
were kept in a hot condition or in a hot and humid condition, and
found to be excellent in heat resistance and moisture resistance,
compared with the polyethylene dioxythiophenes of Comparative
Example 1 as well as the polyethylene dioxythiophenes of
Comparative Examples 2 to 5. The polyethylene dioxythiophenes of
Comparative Examples 2 to 5, which were treated by the organic
sulfonic acid solution, showed a higher electric conductivity than
the polyethylene dioxythiophenes of Examples 1 to 11 as shown in
Test Example 1, but more decreased the electric conductivity when
they were kept in a hot condition or in a hot and humid condition,
so they were inferior to the polyethylene dioxythiophenes of
Examples 1 to 11 in view of the heat resistance and the moisture
resistance.
Examples 12 to 19
[0055] The same procedure were applied as Example 1 to synthesize
the conductive polymer (at a temperature of 25.degree. C. and a
humidity of 60% for a period of 12 hours to carry out the oxidation
polymerization). Then, instead of washing it with 2% paratoluene
sulfonic acid aqueous solution, the ceramic plate forming the
polyethylene dioxythiophene was immersed into ethanol for a period
of 5 minutes, followed by taking it out and drying it at a
temperature of 50.degree. C. for a period of 1 hour. The organic
sulfonate solutions as prepared in accordance with Production
Examples 4, 6, 9 and 12-15, and sodium benzaldehydesulfonate
(manufactured by Wako Pure Chemical Industries Ltd.) were made
their concentration adjusted into 2%, and 100 .mu.l of each of the
solutions was separately dropped on the polyethylene dioxythiophene
formed on the ceramic plate, followed by drying it at room
temperature for a period of 1 hour and further drying it at a
temperature of 200.degree. C. for a period of 10 minutes. In
adjusting the concentration of the Organic sulfonate solution, the
concentration of Production Example 15 was adjusted by using 50%
ethanol aqueous solution, and the others were adjusted by
water.
Examples 20 to 24
[0056] The same procedures were applied as Example 1 to synthesize
the conductive polymer (at a temperature of 25.degree. C. and a
humidity of 60% for a period of 12 hours to carry out the oxidation
polymerization). Then, instead of washing it with 2% paratoluene
sulfonic acid aqueous solution, the ceramic plate forming the
polyethylene dioxythiophene was immersed into ethanol for a period
of 5 minutes, followed by drying it at a temperature of 50.degree.
C. for a period of 1 hour. Then, the organic sulfonate solution of
Production Examples 4, 6 and 14, and the sodium
benzaldehydesulfonate solution, whose concentration was adjusted
into 2% in accordance with Examples 12 to 19, were mixed to have
the ratio (mass ration) of the components as shown in Table 4, and
100 .mu.l of the mixed solutions were separately dropped on the
polyethylene dioxythiophene formed on the ceramic plate, followed
by drying them at room temperature for a period of 1 hour and
further drying them at a temperature of 200.degree. C. for a period
of 10 minutes.
[0057] The mixed solution of the organic sulfonate used in Example
20 includes calcium phenolsulfonate and sodium
benzaldehydesulfonate at a mass ratio of 1:1 as components. The
mixed solution of the organic sulfonate used in Example 21 includes
calcium phenolsulfonate and calcium sulfosalicylate at a mass ratio
of 1:1 as components. The mixed solution of the organic sulfonate
used in Example 22 includes calcium phenolsulfonate and calcium
sulfophthalic at a mass ratio of 1:1 as components. The mixed
solution of the organic sulfonate used in Example 23 includes
calcium phenolsulfonate, calcium sulfosalicylate and calcium
sulfophthalic at a mass ratio of 1:1:1 as components. The mixed
solution of the organic sulfonate used in Example 24 includes
calcium phenolsulfonate, calcium sulfophthalate and sodium
benzaldehydesulfonate at a mass ratio of 1:1:1 as components.
Comparative Example 6
[0058] The same procedures as Example 12 were applied except for
skipping the treatment by the organic sulfonate solution. The
polyethylene dioxythiophene formed on a ceramic plate was immersed
in ethanol, which was then taken out for drying it so as to prepare
the polyethylene dioxythiophene of Comparative Example 6.
Comparative Example 7
[0059] The same procedures as Example 12 were applied except for
replacing the treatment by the organic sulfonate solution of
Example 12 with the treatment by 2% phenol sulfonic acid aqueous
solution, so as to prepare polyethylene dioxythiophene of
Comparative Example 7.
Test Example 4
[0060] To each of the polyethylene dioxythiophenes as prepared in
Examples 12 to 24 and Comparative Examples 6 and 7, a load of 5
tons was applied and kept for a period of 5 minutes for equalizing
the film thickness. Then, the electric conductivity was measured by
using four probes type electric conductivity measuring device
(MCP-T600 manufactured by Mitsubishi Chemical Corporation), in the
same manner as Test Example 1. The results and the components used
for the treatment are summarized in Table 4.
Test Example 5
[0061] With respect to the polyethylene dioxythiophenes of Examples
12 to 24 and Comparative Examples 6 and 7, a storage test in a hot
condition at a temperature of 130.degree. C. for a period of 120
hours in the same manner as Test Example 2 was conducted to
research the decrease rate of the electric conductivity when being
kept in a hot condition. The results are summarized in Table 5.
Test Example 6
[0062] With respect to the polyethylene dioxythiophenes of Examples
12 to 24 and Comparative Examples 6 and 7, a storage test in a hot
and humid condition at a temperature of 85.degree. C. at a humidity
of 85% in the same manner as Test Example 3 was conducted to
research the decrease rate of the electric conductivity when being
kept in a hot and humid condition. The results are summarized in
Table 6. TABLE-US-00004 TABLE 4 Component in the Treatment Electric
Liquid Conductivity(S/cm) Example 12 Calcium phenolsulfonate 110
Example 13 Phenol sulfonic acid 119 imidazole Example 14 Calcium
sulfosalicylate 109 Example 15 Calcium catecholsulfonate 119
Example 16 Calcium cresolsulfonate 115 Example 17 Calcium
sulfophthalate 119 Example 18 Dodecyl calcium 115 phenolsulfonate
Example 19 Sodium benzaldehydesulfonate 120 Example 20 Calcium
phenolsulfonate:sodium 124 benzaldehydesulfonate = 1:1 Example 21
Calcium phenolsulfonate:calcium 110 sulfosalicylate = 1:1 Example
22 Calcium phenolsulfonate:calcium 126 sulfophthalate = 1:1 Example
23 Calcium phenolsulfonate:calcium 119 sulfosalicylate:calcium
sulfophthalate = 1:1:1 Example 24 Calcium phenolsulfonate:calcium
128 sulfophthalate:sodium benzaldehydesulfonate = 1:1:1 Comparative
No Treatment 91 Example 6 Comparative Phenol sulfonic acid 140
Example 7
[0063] TABLE-US-00005 TABLE 5 Decrease Rate of Electric
Conductivity (%) (After storage at 130.degree. C. for 120 hours)
Example 12 32 Example 13 35 Example 14 39 Example 15 29 Example 16
30 Example 17 42 Example 18 35 Example 19 40 Example 20 18 Example
21 18 Example 22 18 Example 23 15 Example 24 11 Comparative 99.1
Example 6 Comparative 64 Example 7
[0064] TABLE-US-00006 TABLE 6 Decrease Rate of Electric
Conductivity (%) (After Storage at 85.degree. C. at a humidity of
85% for 300 hours) Example 12 41 Example 13 39 Example 14 43
Example 15 37 Example 16 36 Example 17 41 Example 18 40 Example 19
41 Example 20 22 Example 21 21 Example 22 22 Example 23 16 Example
24 13 Comparative 92 Example 6 Comparative 62 Example 7
[0065] As shown in Table 4, even in a state where the washing was
not fully done so that the matrix of the conductive polymer was
considered to include considerable amounts of iron components, the
polyethylene dioxythiophenes of Examples 12 to 24, which were
treated by the organic sulfonate solution, showed a higher electric
conductivity than the conductive polymer of Comparative Example 6
which was not treated by the organic sulfonate solution. Also, as
shown in Tables 5 and 6, the polyethylene dioxythiophenes of
Examples 12 to 24 less decreased the electric conductivity when
being kept in a hot condition or in a hot and humid condition, and
found to be excellent in the heat resistance and the moisture
resistance, compared with the polyethylene dioxythiophene of
Comparative Example 6 as well as the polyethylene dioxythiophene of
Comparative Example 7 that was treated by the organic sulfonic acid
solution.
Test Example 7
[0066] With respect to the polyethylene dioxythiophenes in
accordance with Example 4, Example 10, Example 15, Example 20,
Example 24, Comparative Examples 1 to 2, and Comparative Example 4,
a TG-DTA measurement by using SSC5200 manufactured by Seiko
Instruments Inc. was conducted while raising a temperature at a
rate of 5.degree. C./min, from an initial temperature of 30.degree.
C., and in a nitrogen atmosphere, in order to calculate the
decrease rate of the mass in raising the temperature from
100.degree. C. to 240.degree. C. by using the following formula.
The results and the components for the treatment are summarized in
Table 7. Mass Decrease Rate(%)=(Mass decrease rate at 240.degree.
C.)-(Mass decrease rate at 100.degree. C.) TABLE-US-00007 TABLE 7
Mass Component Decrease in the Treatment Liquid Rate(%) Example 4
Calcium phenolsulfonate 0.6 Example 10 Calcium
methoxybenzenesulfonate 0.6 Example 15 Calcium catecholsulfonate
0.6 Example 20 Calcium phenolsulfonate:sodium 0.5
benzaldehydesulfonate = 1:1 Example 24 Calcium
phenolsulfonate:calcium 0.5 sulfophthalate:sodium
benzaldehydesulfonate = 1:1:1 Comparative No Treatment 0.7 Example
1 Comparative Paratoluene sulfonic acid 4.1 Example 2 Comparative
Phenol sulfonic acid 4.4 Example 4
[0067] As shown in Table 7, the polyethylene dioxythiophenes
treated by the Organic sulfonate in accordance with Example 4,
Example 10, Example 15, Example 20 and Example 24 showed a less
decrease rate (%) of the mass compared with the polyethylene
dioxythiophenes treated by the organic sulfonic acid in accordance
with Comparative Example 2 and Comparative Example 4.
[0068] The reasons of the improvement are considered as follows: In
case of Comparative Example 2 or Comparative Example 4 treated by
the organic sulfonic acid where a salt is not formed, the organic
sulfonic acid could be decomposed. On the other hand, in case of
Example 4, Example 10, Example 15, Example 20 and Example 24
treated by the organic sulfonate, the organic sulfonate could be
less decomposed compared with the organic sulfonic acid, resulting
in becoming excellent in the heat resistance.
Test Example 8
[0069] The polyethylene dioxythiophene of Example 4 (that is, the
polyethylene dioxythiophene treated by the calcium phenolsulfonate
aqueous solution as prepared in Production Example 4) and the
polyethylene dioxythiophene of Comparative Example 1 (that is, the
polyethylene dioxythiophene not treated by the Organic sulfonate
solution) were partly peeled off from the ceramic plate by using a
spatula, about 20 mg of which was then separately put into a 20 ml
vial container with a stopple. Then, 1 ml of 70% nitric acid was
added to each of the containers, and closed the stopple for keeping
it at a temperature of 50.degree. C. for a period of 48 hours so as
to completely decompose the polyethylene dioxythiophene. Then, 19
ml of pure water was added, for filtrating it through a 0.2 .mu.m
filter, which was then subjected to measurement of the calcium
amount by using an ICP optical emission spectrometry device,
SPS1200A, manufactured by Seiko Instrument Industries Inc. The
results are summarized in Table 8. TABLE-US-00008 TABLE 8 Calcium
amount Example 4 38 ppm Comparative 0.1 ppm Example 1
[0070] As clearly shown in Table 8, the polyethylene dioxythiophene
of Example 4 well maintained the amount of calcium.
[0071] Also, the polyethylene dioxythiophene of Example 4 was
analyzed by using an EDX [energy dispersive X-ray analyzer,
EMAX-1770 manufactured by Horiba Ltd.]. The analysis found that the
polyethylene dioxythiophene included calcium dispersed
homogenously. From the results here as well as the results shown in
Test Example 7, the polyethylene dioxythiophene of Example 4
included an organic sulfonate homogenously dispersed in or on the
matrix.
[0072] Generally, in case where a washing process is not applied or
iron components remain even after the washing process, it has been
known that the heat resistance and the moisture resistance of the
conductive polymer are inferior to the case where the iron
components are completely removed. This phenomena is considered due
to de-doping by reduction or polymer decomposition by changing a
divalent iron into a trivalent iron. The reason why the treatment
by the organic sulfonate aqueous solution of Examples improved the
heat resistance and moisture resistance compared with the ones not
treated by the organic sulfonate is because the organic sulfonate
restricts the change of the iron valence so as to restrict the
conductive polymer from being de-doped by reduction or
decomposition.
Examples 25 and 26
[0073] In Examples 25 and 26, the conductive polymer prepared by
electrolysis oxidation polymerization was treated by the Organic
sulfonate solution.
[0074] First, a ceramic plate coated with the conductive polymer,
which was used as the anode during the electrolysis oxidation
polymerization, was prepared. That is, as an oxidant, ferric
paratoluenesulfonate solution was used. By conducting the same
procedure as Example 1, a ceramic plate forming a polyethylene
dioxythiophene was obtained. The obtained ceramic plate was used as
an anode, and a stainless steel (SUS304) was used as a cathode, and
the electrolysis oxidation polymerization was carried out by the
following procedure.
[0075] To a solution obtained by solving butyl naphthalene sulfonic
acid sodium into pure water to have a concentration of 0.04 mol/l,
pyrrole was added to have a concentration of 0.04 mol/l. Using the
anode and cathode as explained above, a constant current of 1 mA/cm
was applied for a period of 70 minutes so as to synthesize a
polypyrrole incorporating butyl naphthalene sulfonic acid sodium as
a dopant. Then, it was fully washed with 2% butyl naphthalene
sulfonic acid ethanol solution, and an excessive amount of butyl
naphthalene sulfonic acid was removed by ethanol. Thereby obtained
polypyrrole, together with the ceramic plate, was immersed into 2%
organic sulfonate solution whose concentration was adjusted in
Production Example 4 and Production Example 8, for a period of 10
minutes. Then, the plate was taken out, dried at a temperature of
50.degree. C. for a period of 1 hour, and further dried at a
temperature of 150.degree. C. for a period of 1 hour, so as to
prepare a polypyrrole/polyethylene dioxythiophene complex of
Example 25 and polypyrrole/polyethylene dioxythiophene complex of
Example 26.
Comparative Example 8
[0076] To the polypyrrole/polyethylene dioxythiophene complex
obtained by the electrolysis oxidation polymerization, the same
procedure as Example 25 was conducted except for skipping the
treatment by the organic sulfonate of Example 25, so as to prepare
a polypyrrole/polyethylene dioxythiophene complex of Comparative
Example 8.
Test Example 9
[0077] To the polypyrrole/polyethylene dioxythiophene complex as
prepared in accordance with Example 25, 26 and Comparative Example
8, a load of 1.5 tons was applied for a period of 5 hours to
equalize the film thickness. Then, at room temperature (about
25.degree. C.), a surface resistance was measured by using a four
probes type electric conductivity measuring device [MCP-T600
manufactured by Mitsubishi Chemical Corporation] in accordance with
JIS K 7194. The results and the components are summarized in Table
9. TABLE-US-00009 TABLE 9 Components in the Surface Treatment
Liquid resistance(.OMEGA.) Example 25 Calcium phenolsulfonate 6.8
Example 26 Phenol sulfonic acid amino 6.6 azotoluene Comparative No
Treatment 8.9 Example 8
[0078] As shown in Table 9, the polypyrrole/polyethylene
dioxythiophene complexes in accordance with Examples 25 and 26,
which were treated by the organic sulfonate solution, showed a less
surface resistance and a higher electric conductivity than the
polypyrrole/polyethylene dioxythiophene complex in accordance with
Comparative Example 8, which was not treated by the organic
sulfonate solution.
Test Example 10
[0079] With respect to the polypyrrole/polyethylene dioxythiophene
complexes in accordance with Examples, 25, 26 and Comparative
Example 8, the same procedure as Test Example 2 was conducted
except for changing the storage period into 48 hours and except for
replacing the electric conductivity measurement with a surface
resistance measurement, so as to research the increase rate of the
surface resistance when being kept in a hot condition. The results
are summarized in table 10. The increase rate of the surface
resistance is calculated by the following formula. [Increase Rate
of the Surface Resistance (%)]=[(Surface Resistance after
Storage)/(Initial Surface Resistance)].times.100
[0080] In the formula above, the "initial surface resistance" means
the surface resistance measured before the storage (that is, the
surface resistance measured in accordance with Test Example 9).
TABLE-US-00010 TABLE 10 Increase Rate of Surface Resistance(%)
(After storage at 130.degree. C. for 48 hours) Example 25 480
Example 26 420 Comparative 1200 Example 8
[0081] As shown in Table 10, the polypyrrole/polyethylene
dioxythiophene complexes in accordance with Examples 25 and 26,
which were treated by the organic sulfonate solution, less
increased the surface resistance when being kept at a hot condition
and were found to be excellent in the heat resistance, compared
with the polypyrrole/polyethylene dioxythiophene complex of
Comparative Example 8, which was not treated by the organic
sulfonate solution.
Examples 27 to 29
[0082] Using the polyethylene dioxythiophene of Example 4, the
polyethylene dioxythiophene of Example 6 and the polyethylene
dioxythiophene of Example 7, the solid electrolytic capacitors were
prepared.
[0083] First, a tantalum sintered compact was immersed into a
phosphoric acid aqueous solution, followed by applying an voltage
to carry out electrolytic oxidation. As a result, a dielectric
oxidation film was formed on the surface of the tantalum sintered
compact. Then, in order to carry out chemical oxidation
polymerization, a solution including an oxidant and iron (III)
paratoluenesulfonate as a dopant was prepared. The tantalum
sintered compact whose surface had formed the dielectric oxidation
film was immersed into a solution including iron (III)
paratoluenesulfonate for a period of 20 minutes, followed by taking
it out to dry it at a temperature of 40.degree. C. for a period of
30 minutes. Then, it was immersed into a monomer of ethylene
dioxythiophene for a period of 15 minutes, followed by taking it
out to carry out chemical oxidation polymerization in an atmosphere
of a temperature of about 25.degree. C. at a humidity of 40%. Then,
it was immersed into 2% paratoluene sulfonic acid aqueous solution
for a period of 60 minutes, and then, immersed into pure water for
a period of 30 minutes for washing, followed by drying it at a
temperature of 80.degree. C. for a period of 30 minutes. Further,
the steps of immersing it into the solution including iron (III)
paratoluenesulfonate for a period of 20 minutes followed by washing
and drying were repeated for ten times, so as to synthesize
polyethylene dioxythiophene. Then, after it was immersed into a
phosphoric acid aqueous solution, a voltage was applied to
repeating the synthesis. Thereafter, each of the samples was
immersed into the organic sulfonate aqueous solution obtained by
adjusting the concentration of the Organic sulfonate solution into
2% in accordance with Production Example 4, Production Example 6
and Production Example 7, for a period of 20 minutes, followed by
drying it at a temperature of 100.degree. C. for a period of 30
minutes. Then, a carbon paste and a silver paste were applied, and
an anode lead and a cathode lead were provided to be taken from the
anode layer and the cathode layer, respectively. Then, an outer
shell was formed by an epoxy resin around the area. Finally, an
aging treatment was applied so as to obtain a solid electrolytic
capacitor.
Comparative Example 9
[0084] The same procedure as Example 27 was applied except for
skipping the treatment of the polyethylene dioxythiophene into an
organic sulfonate solution, so as to prepare a solid electrolytic
capacitor.
Comparative Example 10
[0085] The same procedure as Example 27 was applied to the
polyethylene dioxythiophene, except for replacing the treatment by
the organic sulfonate solution in Example 27 with the treatment by
2% phenol sulfonic aqueous solution, so as to prepare a solid
electrolytic capacitor.
Test Example 11
[0086] The solid electrolytic capacitors in accordance with
Examples 27 to 29 and Comparative Examples 9 and 10 were kept at a
temperature of 85.degree. C. at a humidity of 85% for a period of
1000 hours, to measure the capacitance. The capacitance was also
measured before the storage, which was referred to as an initial
property. Compared with the initial property, the capacitance ratio
after the storage is shown in table 11. Also, with respect to the
solid electrolytic capacitors in accordance with Examples 27 to 29
and Comparative Examples 9 and 10, the equivalent series resistance
(ESR) was measured. The results and the components are summarized
in Table 11. TABLE-US-00011 TABLE 11 Equivalent Series Components
in the Capacitance Resistance Treatment Liquid (%) (%) Example 27
Calcium 95 118 phenolsulfonate Example 28 Calcium 93 116
sulfosalicylate Example 29 Aluminum 94 114 phenolsulfonate
Comparative No Treatment 85 160 Example 9 Comparative Phenol
sulfonic acid 75 139 Example 10
[0087] As shown in Table 11, the solid electrolytic capacitors of
Examples 27 to 29, using the polyethylene dioxythiophene treated by
the organic sulfonate solution, less decreased the capacitance and
to change the equivalent series resistance when being kept in a hot
and humid condition, resulting in being excellent in the heat
resistance and the moisture resistance, compared with the solid
electrolytic capacitor of Comparative Example 9 which was not
treated by the organic sulfonate solution and the solid
electrolytic capacitor of Comparative Example 10 which was treated
by the organic sulfonic acid solution.
INDUSTRIAL UTILITY
[0088] As explained above, the conductive polymer of the present
invention is excellent in the conductivity, heat resistance and
moisture resistance, and less decreased the electric conductivity
when being kept in a hot and humid condition, and to decompose in a
hot condition. Therefore, the solid electrolytic capacitor using
the conductive polymer as a solid electrolyte of the present
invention less decreased the properties in a hot and humid
condition, resulting in being reliable.
* * * * *