U.S. patent application number 13/897510 was filed with the patent office on 2013-11-07 for conductive polymer solution, conductive coating, condenser and process for manufacturing condenser.
This patent application is currently assigned to SHIN-ETSU POLYMER CO., LTD.. The applicant listed for this patent is Rika Abe, Yasushi Masahiro, Sou Matsubayashi, Mitsuaki Negishi, Tailu NING, Kazuyoshi Yoshida. Invention is credited to Rika Abe, Yasushi Masahiro, Sou Matsubayashi, Mitsuaki Negishi, Tailu NING, Kazuyoshi Yoshida.
Application Number | 20130294013 13/897510 |
Document ID | / |
Family ID | 38345250 |
Filed Date | 2013-11-07 |
United States Patent
Application |
20130294013 |
Kind Code |
A1 |
NING; Tailu ; et
al. |
November 7, 2013 |
CONDUCTIVE POLYMER SOLUTION, CONDUCTIVE COATING, CONDENSER AND
PROCESS FOR MANUFACTURING CONDENSER
Abstract
The object of the present invention is to provide a condenser
that exhibits excellent conductivity of the solid electrolyte
layer, and has a low ESR, a high degree of heat resistance, and a
high withstand voltage. A condenser of the present invention
includes an anode composed of a valve metal, a dielectric layer
formed by oxidation of the surface of the anode, and a solid
electrolyte layer formed on the surface of the dielectric layer,
wherein the solid electrolyte layer contains a .pi.-conjugated
conductive polymer, a polyanion, and an amide compound.
Inventors: |
NING; Tailu; (Saitama-shi,
JP) ; Yoshida; Kazuyoshi; (Kazo-shi, JP) ;
Masahiro; Yasushi; (Saitama-shi, JP) ; Matsubayashi;
Sou; (Koshigaya-shi, JP) ; Abe; Rika;
(Kawagoe-shi, JP) ; Negishi; Mitsuaki;
(Kitakatsushika-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NING; Tailu
Yoshida; Kazuyoshi
Masahiro; Yasushi
Matsubayashi; Sou
Abe; Rika
Negishi; Mitsuaki |
Saitama-shi
Kazo-shi
Saitama-shi
Koshigaya-shi
Kawagoe-shi
Kitakatsushika-gun |
|
JP
JP
JP
JP
JP
JP |
|
|
Assignee: |
SHIN-ETSU POLYMER CO., LTD.
Tokyo
JP
|
Family ID: |
38345250 |
Appl. No.: |
13/897510 |
Filed: |
May 20, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12278605 |
Aug 7, 2008 |
8472165 |
|
|
PCT/JP2007/052277 |
Feb 8, 2007 |
|
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|
13897510 |
|
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Current U.S.
Class: |
361/525 ;
252/62.2; 29/25.03 |
Current CPC
Class: |
C09D 5/24 20130101; H01G
9/042 20130101; H01G 9/0036 20130101; H01G 11/48 20130101; H01B
1/124 20130101; Y02E 60/13 20130101; H01G 11/52 20130101; C08L
65/02 20130101; H01G 9/028 20130101; H01G 11/56 20130101; H01G
9/0029 20130101; C08K 5/20 20130101; H01G 9/025 20130101; C08L
65/00 20130101 |
Class at
Publication: |
361/525 ;
29/25.03; 252/62.2 |
International
Class: |
H01G 9/025 20060101
H01G009/025; H01G 9/00 20060101 H01G009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 9, 2006 |
JP |
P2006-032174 |
Mar 3, 2006 |
JP |
P2006-058169 |
Mar 16, 2006 |
JP |
P2006-072711 |
Mar 20, 2006 |
JP |
P2006-076277 |
Jul 20, 2006 |
JP |
P2006-198114 |
Claims
1. A condenser, comprising an anode composed of a valve metal, a
dielectric layer formed by oxidation of a surface of said anode,
and a solid electrolyte layer formed on a surface of said
dielectric layer, wherein said solid electrolyte layer comprises a
.pi.-conjugated conductive polymer, a polyanion, a conductivity
improver, and a silane coupling agent, and wherein said solid
electrolyte layer is provided from a conductive polymer solution,
and said conductive polymer solution comprises an alkaline
compound.
2. The condenser according to claim 1, wherein said conductivity
improver is one or more compounds selected from the group
consisting of nitrogen-containing aromatic cyclic compounds,
compounds containing two or more hydroxyl groups, compounds
containing two or more carboxyl groups, compounds containing one or
more hydroxyl groups and one or more carboxyl groups, compounds
containing an amide group, compounds containing an imide group,
lactam compounds, and compounds containing a glycidyl group.
3. A process for manufacturing a condenser of claim 1, comprising:
adhering a conductive polymer solution comprising a .pi.-conjugated
conductive polymer, a polyanion, a conductivity improver, an
alkaline compound, a silane coupling agent and a solvent to a
surface of a dielectric layer formed by oxidizing a surface of an
anode composed of a valve metal, and drying said conductive polymer
solution adhered to said surface of said dielectric layer.
4. A conductive polymer solution comprising a .pi.-conjugated
conductive polymer, a polyanion, a conductivity improver selected
from the group consisting of nitrogen-containing aromatic cyclic
compounds, compounds containing two or more carboxyl groups,
compounds containing one or more hydroxyl groups and one or more
carboxyl groups, compounds containing an imide group, and compounds
containing a glycidyl group, an alkaline compound and a
solvent.
5. The conductive polymer solution according to claim 4, wherein
said alkaline compound is a nitrogen-containing aromatic cyclic
compound.
6. The conductive polymer solution according to claim 4, wherein
said solvent is a mixed solvent containing water and an organic
solvent having a boiling point of 100.degree. C. or higher at a
pressure of 0.1 MPa.
7. A conductive coating, formed by applying and drying a conductive
polymer solution of claim 4.
8. A condenser, comprising an anode composed of a valve metal, a
dielectric layer formed by oxidation of a surface of said anode,
and a solid electrolyte layer formed on a surface of said
dielectric layer, wherein said solid electrolyte layer is formed
from a conductive coating of claim 7.
9. A process for manufacturing a condenser, comprising: forming a
solid electrolyte layer by applying a conductive polymer solution
of claim 4 to a surface of a dielectric layer formed by oxidizing a
surface of an anode composed of a valve metal.
Description
[0001] The present application is a continuation of U.S. patent
application Ser. No. 12/278,605, which is a national phase
conversion of PCT/JP2007/052277, filed Feb. 8, 2007, which claims
priority of Japanese Patent Application No. 2006-32174, filed Feb.
9, 2006, Japanese Patent Application No. 2006-58169, filed Mar. 3,
2006, Japanese Patent Application No. 2006-72711, filed Mar. 16,
2006, Japanese Patent Application No. 2006-76277, filed Mar. 20,
2006, and Japanese Patent Application No. 2006-198114, filed Jul.
20, 2006, the contents of which are incorporated herein by
reference. The PCT International Application was published in the
Japanese language.
TECHNICAL FIELD
[0002] The present invention relates to a condenser such as an
aluminum electrolytic condenser, a tantalum electrolytic condenser
or a niobium electrolytic condenser, and a process for
manufacturing such a condenser. The present invention also relates
to a conductive polymer solution and a conductive coating
containing a .pi.-conjugated conductive polymer.
BACKGROUND ART
[0003] In recent years, accompanying the digitalization of
electronic equipment, there has been a growing demand for
reductions in the high-frequency region impedance (the equivalent
series resistance (hereafter also abbreviated as ESR)) of the
condensers used in the electronic equipment. Conventionally, in
order to satisfy these demands, so-called functional condensers
(hereafter abbreviated to simply "condensers") that use an oxide
film of a valve metal such as aluminum, tantalum or niobium as a
dielectric body have been used.
[0004] As disclosed in Patent Document 1, the structures of these
condensers typically include an anode composed of a porous body of
a valve metal, a dielectric layer formed by oxidizing the surface
of the anode, a conductive solid electrolyte layer, and a cathode
on which is laminated a carbon layer or a silver layer or the like.
A conductive film containing a .pi.-conjugated conductive polymer
may be used as the solid electrolyte layer.
[0005] Widely known processes for forming a conductive film
containing a .pi.-conjugated conductive polymer include
electrolytic polymerization processes in which a conductive layer
composed of a manganese oxide is formed in advance on the surface
of a valve metal porous body, and this conductive layer is then
used as an electrode for performing the electrolytic polymerization
(see Patent Document 2), and chemical oxidative polymerization
processes in which a precursor monomer that generates the
.pi.-conjugated conductive polymer is polymerized using an oxidant
(see Patent Document 3).
[0006] As a process for forming a conductive film other than the
electrolytic polymerization process and chemical oxidative
polymerization process described above, a process has been proposed
in which aniline is subjected to a chemical oxidative
polymerization in the presence of a polyanion having, for example,
a sulfo group and a carboxyl group, thereby forming a water-soluble
polyaniline, and then applying and drying an aqueous solution of
the polyaniline to form a coating (see Patent Document 4). With
this process, a conductive film with a high degree of conductivity
can be formed relatively simply.
[0007] Further, condensers require a high capacitance. In order to
achieve a high capacitance, a process has been proposed in which,
by finely controlling the temperature conditions of the chemical
oxidative polymerization, the solid electrolyte layer can be formed
satisfactorily within the interior of the dielectric layer (see
Patent Document 5).
[0008] Moreover, in order to prevent shorting between the anode and
the solid electrolyte layer, a solid electrolytic condenser has
been proposed in which a polyimide silicone layer is first formed
on the surface of the dielectric layer, and an oxidative
polymerization process is then used to form a conductive polymer
layer (see Patent Document 6). [0009] [Patent Document 1] [0010]
Japanese Unexamined Patent Application, First Publication No.
2003-37024 [0011] [Patent Document 2] [0012] Japanese Unexamined
Patent Application, First Publication No. Sho 63-158829 [0013]
[Patent Document 3] [0014] Japanese Unexamined Patent Application,
First Publication No. Sho 63-173313 [0015] [Patent Document 4]
[0016] Japanese Unexamined Patent Application, First Publication
No. Hei 7-105718 [0017] [Patent Document 5] [0018] Japanese
Unexamined Patent Application, First Publication No. Hei 11-74157
[0019] [Patent Document 6] [0020] Japanese Unexamined Patent
Application, First Publication No. 2005-109079
DISCLOSURE OF INVENTION
Problems to be Solved by the Invention
[0021] However, in the electrolytic polymerization process
disclosed in Patent Document 2, the step of forming the conductive
layer composed of a manganese oxide is not only complex, but the
formed manganese oxide has also low conductivity, and therefore a
problem arises in that the effect of using a highly conductive
.pi.-conjugated conductive polymer is weakened.
[0022] Furthermore, in the chemical oxidative polymerization
process disclosed in Patent Document 3, the polymerization time is
long, and repeated polymerizations must be performed to ensure the
required film thickness, meaning the formation efficiency for the
conductive film is poor, and the conductivity achieved is also
lower than that obtained using an electrolytic polymerization. If
the conductivity of the condenser is low, then a problem arises in
that the equivalent series resistance increases.
[0023] Moreover, in, the process for manufacturing a conductive
film disclosed in Patent Document 4, because the film includes a
non-conductive polyanion, the conductivity of the resulting
conductive film is low.
[0024] Furthermore, when forming the solid electrolyte layer of a
condenser, if the conductive film formation processes disclosed in
Patent Documents 2 to 4 are employed, then another problem arises
in that the withstand voltage of the condenser tends to fall. A
generally known process for increasing the withstand voltage
involves increasing the anodization voltage and increasing the
thickness of the dielectric layer, but if the dielectric layer is
increased in thickness, then the condenser also becomes thicker,
making it impossible to satisfy recent demands for thinner
devices.
[0025] Moreover, with the polyaniline aqueous solution obtained in
the process disclosed in Patent Document 4, because corrosion of
the dielectric layer can not be prevented satisfactorily, it is
impossible to prevent increases in the leakage current from the
dielectric layer. As a result, a condenser that uses a conductive
coating formed from the polyaniline aqueous solution disclosed in
Patent Document 4 as the solid electrolyte layer suffers from
increased equivalent series resistance (ESR), meaning the condenser
is unable to conform to recent demands for reduced impedance.
[0026] Further, in the process disclosed in Patent Document 5,
although the capacitance of the condenser is able to be increased,
an already complex chemical oxidative polymerization is often made
even more complex, meaning the process is impractical in terms of
simplifying the manufacturing process and reducing the
manufacturing costs.
[0027] Moreover, because condensers may sometimes be used in
high-temperature environments, they require heat resistance, but
even if a solid electrolyte layer is formed using one of the
processes disclosed in Patent Documents 2 to 5, achieving a
condenser with a high degree of heat resistance is still
problematic.
[0028] In addition, in the condenser disclosed in Patent Document
6, although the polyimide silicone layer exhibits excellent
adhesiveness, when exposed to thermal stress it is unable to
prevent shorting between the anode and the solid electrolyte layer.
Further, based on investigations conducted by the inventors of the
present invention into the cause of this problem, it was discovered
that the difference in the coefficients of thermal expansion for
the polyimide silicone layer and the dielectric layer was very
large, and this difference caused defects within the dielectric
layer as it was unable to conform to the thermal expansion of the
polyimide silicone layer.
[0029] An object of the present invention is to provide a condenser
that exhibits excellent conductivity of the solid electrolyte
layer, and has a low ESR and a high degree of heat resistance.
Furthermore, another object of the present invention is to provide
a process for manufacturing a condenser that is capable of simply
manufacturing a condenser that has a low ESR, a high degree of heat
resistance and a high capacitance.
[0030] Yet another object of the present invention is to provide a
condenser that exhibits a high withstand voltage even when the
thickness of the dielectric layer is reduced. Furthermore, yet
another object of the present invention is to provide a process for
manufacturing a condenser that is capable of simply manufacturing a
condenser that exhibits a high withstand voltage even when the
thickness of the dielectric layer is reduced.
[0031] Moreover, yet another object of the present invention is to
provide a condenser in which shorting between the anode and the
solid electrolyte layer is prevented even upon exposure to thermal
stress. Yet another object is to provide a process for simply
manufacturing such a condenser.
[0032] In addition, yet another object of the present invention is
to provide a conductive polymer solution that is capable of forming
a highly conductive coating and yet exhibits minimal corrosive
properties. Further, yet another object is to provide a conductive
coating that exhibits a high degree of conductivity but minimal
corrosive properties.
Means to Solve the Problems
[0033] A condenser according to a first aspect of the present
invention is a condenser including an anode composed of a porous
body of a valve metal, a dielectric layer formed by oxidation of
the surface of the anode, and a solid electrolyte layer formed on
the surface of the dielectric layer, wherein
[0034] the solid electrolyte layer contains a .pi.-conjugated
conductive polymer, a polyanion, and an amide compound.
[0035] In the condenser of the present invention, the amide
compound preferably contains one or more hydroxyl groups.
[0036] In the condenser of the present invention, the solid
electrolyte layer preferably further contains an ion-conductive
polymer.
[0037] In the condenser of the present invention, the amide
compound may be a compound represented by Chemical Formula (1)
shown below.
##STR00001##
(wherein, R.sup.1 and R.sup.2 each independently represent a
hydrogen atom, or an alkyl group or an alkylene group that may be
substituted)
[0038] In the condenser of the present invention, the quantity of
the compound represented by Chemical Formula (1) within the solid
electrolyte layer is preferably within a range from 15 to 60% by
mass.
[0039] Furthermore, a condenser according to a second aspect of the
present invention is a condenser including an anode composed of a
porous body of a valve metal, a dielectric layer formed by
oxidation of the surface of the anode, and a solid electrolyte
layer formed on the surface of the dielectric layer, wherein
[0040] the solid electrolyte layer contains a .pi.-conjugated
conductive polymer, a polyanion, a conductivity improver, and a
silane coupling agent.
[0041] In the condenser according to this aspect of the present
invention, the conductivity improver is preferably one or more
compounds selected from the group consisting of nitrogen-containing
aromatic cyclic compounds, compounds containing two or more
hydroxyl groups, compounds containing two or more carboxyl groups,
compounds containing one or more hydroxyl groups and one or more
carboxyl groups, compounds containing an amide group, compounds
containing an imide group, lactam compounds, and compounds
containing a glycidyl group.
[0042] Furthermore, a condenser according to a third aspect of the
present invention is a condenser including an anode composed of a
valve metal, a dielectric layer that is an oxidized film of the
anode formed on the surface of the anode, and a solid electrolyte
layer that is formed on the opposite side from the anode of the
dielectric layer and contains a .pi.-conjugated conductive polymer,
wherein
[0043] an intermediate layer containing a low-thermal expansion
polymer having an average coefficient of thermal expansion within a
range from 30 to 120.degree. C. of not more than 300 ppm/.degree.
C. is provided between the dielectric layer and the solid
electrolyte layer.
[0044] A process for manufacturing a condenser according to the
present invention includes: adhering a conductive polymer solution
containing a .pi.-conjugated conductive polymer, a polyanion, an
amide compound and a solvent to the surface of a dielectric layer
formed by oxidizing the surface of an anode composed of a porous
body of a valve metal, and
[0045] drying the conductive polymer solution adhered to the
surface of the dielectric layer.
[0046] In the process for manufacturing a condenser according to
the present invention, the amide compound may be a compound
represented by Chemical Formula (1) shown above.
[0047] Furthermore, another aspect of the process for manufacturing
a condenser of the present invention includes: adhering a
conductive polymer solution containing a .pi.-conjugated conductive
polymer, a polyanion, a conductivity improver, a silane coupling
agent and a solvent to the surface of a dielectric layer formed by
oxidizing the surface of an anode composed of a porous body of a
valve metal, and
[0048] drying the conductive polymer solution adhered to the
surface of the dielectric layer.
[0049] In a process for manufacturing a condenser according to the
present invention, the pH of the conductive polymer solution at
25.degree. C. is preferably within a range from 3 to 13.
[0050] Furthermore, yet another aspect of the process for
manufacturing a condenser of the present invention includes:
applying a low-thermal expansion polymer solution, prepared by
dissolving a low-thermal expansion polymer having an average
coefficient of thermal expansion within a range from 30 to
120.degree. C. of not more than 300 ppm/.degree. C. in a solvent,
to the surface of a dielectric layer formed by oxidizing one
surface of an anode composed of a valve metal, thereby forming an
intermediate layer, and
[0051] applying a conductive polymer solution, prepared by
dissolving a .pi.-conjugated conductive polymer and a polyanion in
a solvent, to the surface of the intermediate layer, thereby
forming a solid electrolyte layer.
[0052] A conductive polymer solution of the present invention
contains a .pi.-conjugated conductive polymer, a polyanion, a
conductivity improver, an alkaline compound and a solvent.
[0053] In the conductive polymer solution of the present invention,
the conductivity improver is preferably one or more compounds
selected from the group consisting of nitrogen-containing aromatic
cyclic compounds, compounds containing two or more hydroxyl groups,
compounds containing two or more carboxyl groups, compounds
containing one or more hydroxyl groups and one or more carboxyl
groups, compounds containing an amide group, compounds containing
an imide group, lactam compounds, and compounds containing a
glycidyl group.
[0054] In the conductive polymer solution of the present invention,
the alkaline compound is preferably a nitrogen-containing aromatic
cyclic compound.
[0055] In the conductive polymer solution of the present invention,
the solvent is preferably a mixed solvent containing water and an
organic solvent having a boiling point of 100.degree. C. or higher
at a pressure of 0.1 MPa.
[0056] A conductive coating of the present invention is formed by
applying and drying the conductive polymer solution described
above.
[0057] A condenser of the present invention includes an anode
composed of a porous body of a valve metal, a dielectric layer
formed by oxidation of the surface of the anode, and a solid
electrolyte layer, wherein the solid electrolyte layer is formed
from the conductive coating described above.
[0058] A process for manufacturing a condenser according to the
present invention includes: forming a solid electrolyte layer by
applying the conductive polymer solution described above to the
surface of a dielectric layer formed by oxidizing the surface of an
anode composed of a valve metal.
Effect of the Invention
[0059] A condenser of the present invention exhibits excellent
conductivity of the solid electrolyte layer, and has a low ESR and
a high degree of heat resistance. In addition, because shorting
between the anode and the solid electrolyte layer is prevented even
upon exposure to thermal stress, the failure rate during
manufacture of the condenser can be reduced. Moreover, a condenser
of the present invention exhibits a high withstand voltage even
when the thickness of the dielectric layer is reduced.
[0060] According to a process for manufacturing a condenser
according to the present invention, a condenser that has a low ESR,
a high degree of heat resistance and a high capacitance, and in
which shorting between the anode and the solid electrolyte layer is
prevented even upon exposure to thermal stress, can be produced
simply. Further, according to the process for manufacturing a
condenser of the present invention, the withstand voltage is high
even when the thickness of the dielectric layer is reduced.
[0061] A conductive polymer solution of the present invention is
capable of forming a coating of high conductivity, and also
exhibits minimal corrosive properties. Further, a conductive
coating of the present invention has a high degree of conductivity
and minimal corrosive properties.
BRIEF DESCRIPTION OF THE DRAWINGS
[0062] FIG. 1 is a cross-sectional view showing one embodiment of a
condenser of the present invention.
[0063] FIG. 2 is a cross-sectional view showing another embodiment
of the condenser of the present invention.
[0064] FIG. 3 is a perspective illustration showing yet another
embodiment of the condenser of the present invention.
DESCRIPTION OF THE REFERENCE SYMBOLS
[0065] 10 Condenser [0066] 11 Anode [0067] 12 Dielectric layer
[0068] 13 Solid electrolyte layer [0069] 14 Cathode [0070] 15
Separator [0071] 16 Intermediate layer
BEST MODE FOR CARRYING OUT THE INVENTION
<Condenser>
[0072] An embodiment of a condenser of the present invention is
described below.
[0073] FIG. 1 is a diagram showing the structure of the condenser
of this embodiment. A condenser 10 of the present embodiment has a
basic structure including an anode 11 composed of a porous body of
a valve metal, a dielectric layer 12 that is formed by oxidation of
the surface of the anode 11, a solid electrolyte layer 13 that is
formed on the surface of the dielectric layer 12, and a cathode
14.
[0074] Furthermore, as shown in FIG. 2, in another embodiment of
the condenser of the present invention, the condenser 10 has a
basic structure that includes an intermediate layer 16 provided
between the dielectric layer 12 and the solid electrolyte layer
13.
(Anode)
[0075] Examples of the valve metal that constitute the anode 11
include aluminum, tantalum, niobium, titanium, hafnium, zirconium,
zinc, tungsten, bismuth and antimony. Of these, aluminum, tantalum
and niobium are preferred as they can form a dense dielectric layer
with a high degree of durability, and also enable a high
capacitance to be obtained in a stable manner.
[0076] Specific examples of the anode 11 include anodes prepared by
etching an aluminum foil to increase the surface area, and then
subjecting the surface to an oxidation treatment, and anodes
prepared by subjecting the surface of a sintered body of tantalum
particles or niobium particles to an oxidation treatment, and then
forming pellets. An anode 11 treated in this manner has
irregularities formed within the surface.
(Dielectric Layer)
[0077] The dielectric layer 12 is formed, for example, by
anodization of the surface of the anode 11 within an electrolyte
such as an aqueous solution of ammonium adipate. Accordingly, as
shown in FIG. 1, the dielectric layer 12 conforms and follows the
irregular surface of the anode 11.
[0078] The dielectric layer 12 formed from the oxidized film of the
above valve metal generally has a coefficient of thermal expansion
that is not more than 15 ppm/.degree. C. For example, in those
cases where the dielectric layer 12 is formed from aluminum oxide,
the coefficient of thermal expansion is within a range from
approximately 5 to 7 ppm/.degree. C. The coefficient of thermal
expansion for an oxide of a metal is generally smaller than that
for the metal itself, and therefore in those cases where the
dielectric layer 12 is formed from tantalum oxide, it is assumed
that the coefficient of thermal expansion will be not more than the
6.5 ppm/.degree. C. that represents the coefficient of thermal
expansion of metallic tantalum.
(Intermediate Layer)
[0079] The intermediate layer 16 is a layer containing a
low-thermal expansion polymer having an average coefficient of
thermal expansion within a range from 30 to 120.degree. C. of not
more than 300 ppm/.degree. C. Examples of this low-thermal
expansion polymer include polyurethanes, polyesters, polyamides,
polyimides, polyetherimides, polyetherketones,
polyetheretherketones, polycarbonates, phenolic resins, melamine
resins, and acrylic resins and the like.
[0080] The upper limit for the average coefficient of thermal
expansion of the low-thermal expansion polymer within the range
from 30 to 120.degree. C. is preferably 150 ppm/.degree. C., and
the lower limit is preferably 2 ppm/.degree. C., and even more
preferably 5 ppm/.degree. C.
[0081] Furthermore, in order to reduce the failure rate during
manufacture, the low-thermal expansion polymer preferably has a
coefficient of thermal expansion within a range from room
temperature to approximately 150.degree. C. that is substantially
equal to the coefficient of thermal expansion for the dielectric
layer 12.
[0082] The quantity of the low-thermal expansion polymer within the
intermediate layer 16 is preferably within a range from 0.5 to 100%
by mass. Provided the quantity of the low-thermal expansion polymer
is at least 0.5% by mass, shorting between the anode 11 and the
solid electrolyte layer 13 caused by thermal stress can be
effectively prevented.
(Solid Electrolyte Layer)
[0083] The solid electrolyte layer 13 is a layer that includes, as
essential components, a .pi.-conjugated conductive polymer, a
polyanion, and either an amide compound or a combination of a
conductivity improver and a silane coupling agent. The thickness of
the solid electrolyte layer 13 is preferably within a range from 1
to 50 .mu.m.
<.pi.-Conjugated Conductive Polymer>
[0084] The .pi.-conjugated conductive polymer can use any organic
polymer in which the main chain is composed of a .pi.-conjugated
system. Examples include polypyrroles, polythiophenes,
polyacetylenes, polyphenylenes, polyphenylenevinylenes,
polyanilines, polyacenes, polythiophenevinylenes, and copolymers
thereof. In terms of the ease of polymerization, and the stability
of the polymer in air, polypyrroles, polythiophenes and
polyanilines are preferred.
[0085] The .pi.-conjugated conductive polymer is able to provide
adequate conductivity even in an unsubstituted form, but in order
to further enhance the conductivity, it is preferable that
functional groups such as alkyl groups, carboxyl groups, sulfo
groups, alkoxyl groups, hydroxyl groups and cyano groups are
introduced into the .pi.-conjugated conductive polymer.
[0086] Specific examples of this type of .pi.-conjugated conductive
polymer include polypyrrole, poly(N-methylpyrrole),
poly(3-methylpyrrole), poly(3-ethylpyrrole),
poly(3-n-propylpyrrole), poly(3-butylpyrrole),
poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3-dodecylpyrrole),
poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole),
poly(3-carboxypyrrole), poly(3-methyl-4-carboxypyrrole),
poly(3-methyl-4-carboxyethylpyrrole),
poly(3-methyl-4-carboxybutylpyrrole), poly(3-hydroxypyrrole),
poly(3-methoxypyrrole), poly(3-ethoxypyrrole),
poly(3-butoxypyrrole), poly(3-hexyloxypyrrole),
poly(3-methyl-4-hexyloxypyrrole), polythiophene,
poly(3-methylthiophene), poly(3-ethylthiophene),
poly(3-propylthiophene), poly(3-butylthiophene),
poly(3-hexylthiophene), poly(3-heptylthiophene),
poly(3-octylthiophene), poly(3-decylthiophene),
poly(3-dodecylthiophene), poly(3-octadecylthiophene),
poly(3-bromothiophene), poly(3-chlorothiophene),
poly(3-iodothiophene), poly(3-cyanothiophene),
poly(3-phenylthiophene), poly(3,4-dimethylthiophene),
poly(3,4-dibutylthiophene), poly(3-hydroxythiophene),
poly(3-methoxythiophene), poly(3-ethoxythiophene),
poly(3-butoxythiophene), poly(3-hexyloxythiophene),
poly(3-heptyloxythiophene), poly(3-octyloxythiophene),
poly(3-decyloxythiophene), poly(3-dodecyloxythiophene),
poly(3-octadecyloxythiophene), poly(3,4-dihydroxythiophene),
poly(3,4-dimethoxythiophene), poly(3,4-diethoxythiophene),
poly(3,4-dipropoxythiophene), poly(3,4-dibutoxythiophene),
poly(3,4-dihexyloxythiophene), poly(3,4-diheptyloxythiophene),
poly(3,4-dioctyloxythiophene), poly(3,4-didecyloxythiophene),
poly(3,4-didodecyloxythiophene), poly(3,4-ethylenedioxythiophene),
poly(3,4-propylenedioxythiophene), poly(3,4-butenedioxythiophene),
poly(3-methyl-4-methoxythiophene),
poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene),
poly(3-methyl-4-carboxythiophene),
poly(3-methyl-4-carboxyethylthiophene),
poly(3-methyl-4-carboxybutylthiophene), polyaniline,
poly(2-methylaniline), poly(3-isobutylaniline),
poly(2-anilinesulfonic acid), and poly(3-anilinesulfonic acid).
[0087] Of these, a (co)polymer composed of either one or two
compounds selected from polypyrrole, polythiophene,
poly(N-methylpyrrole), poly(3-methylthiophene),
poly(3-methoxythiophene) and poly(3,4-ethylenedioxythiophene) can
be used particularly favorably in terms of the resistance and the
reactivity. Moreover, polypyrrole and
poly(3,4-ethylenedioxythiophene) yield a greater increase in
conductivity and also offer improved heat resistance, and are
therefore particularly desirable.
[0088] The quantity of the .pi.-conjugated conductive polymer
within the solid electrolyte layer 13 is preferably at least 1% by
mass, and is even more preferably 5% by mass or more.
<Polyanion>
[0089] The polyanion is a homopolymer or copolymer selected from
substituted or unsubstituted polyalkylenes, substituted or
unsubstituted polyalkenylenes, substituted or unsubstituted
polyimides, substituted or unsubstituted polyamides and substituted
or unsubstituted polyesters, and is composed of structural units
having an anion group. If required, the polyanion may also include
structural units having no anion group.
[0090] The polyanion not only makes the .pi.-conjugated conductive
polymer soluble in the solvent, but also functions as a dopant for
the .pi.-conjugated conductive polymer.
[0091] Here, a polyalkylene describes a polymer in which the main
chain is composed of repeating methylene units. Examples include
polyethylene, polypropylene, polybutene, polypentene, polyhexene,
polyvinyl alcohol, polyvinylphenol, poly(3,3,3-trifluoropropylene),
polyacrylonitrile, polyacrylate and polystyrene.
[0092] A polyalkenylene is a polymer composed of structural units
having one or more unsaturated bonds (vinyl groups) within the main
chain. Of these, substituted or unsubstituted butenylenes are
preferred because they exhibit an interaction between the
unsaturated bonds and the .pi.-conjugated conductive polymer, and
are readily synthesized using a substituted or unsubstituted
butadiene as the starting material.
[0093] Specific examples of the polyalkenylenes include polymers
containing one or more structural units selected from propenylene,
1-methylpropenylene, 1-butylpropenylene, 1-decylpropenylene,
1-cyanopropenylene, 1-phenylpropenylene, 1-hydroxypropenylene,
1-butenylene, 1-methyl-1-butenylene, 1-ethyl-1-butenylene,
1-octyl-1-butenylene, 1-pentadecyl-1-butenylene,
2-methyl-1-butenylene, 2-ethyl-1-butenylene, 2-butyl-1-butenylene,
2-hexyl-1-butenylene, 2-octyl-1-butenylene, 2-decyl-1-butenylene,
2-dodecyl-1-butenylene, 2-phenyl-1-butenylene, 2-butenylene,
1-methyl-2-butenylene, 1-ethyl-2-butenylene, 1-octyl-2-butenylene,
1-pentadecyl-2-butenylene, 2-methyl-2-butenylene,
2-ethyl-2-butenylene, 2-butyl-2-butenylene, 2-hexyl-2-butenylene,
2-octyl-2-butenylene, 2-decyl-2-butenylene, 2-dodecyl-2-butenylene,
2-phenyl-2-butenylene, 2-propylenephenyl-2-butenylene,
3-methyl-2-butenylene, 3-ethyl-2-butenylene, 3-butyl-2-butenylene,
3-hexyl-2-butenylene, 3-octyl-2-butenylene, 3-decyl-2-butenylene,
3-dodecyl-2-butenylene, 3-phenyl-2-butenylene,
3-propylenephenyl-2-butenylene, 2-pentenylene,
4-propyl-2-pentenylene, 4-butyl-2-pentenylene,
4-hexyl-2-pentenylene, 4-cyano-2-pentenylene,
3-methyl-2-pentenylene, 4-ethyl-2-pentenylene,
3-phenyl-2-pentenylene, 4-hydroxy-2-pentenylene, and hexenylene and
the like.
[0094] Examples of the polyimides include polyimides formed from an
anhydride such as pyromellitic dianhydride, biphenyltetracarboxylic
dianhydride, benzophenone tetracarboxylic dianhydride,
2,2',3,3'-tetracarboxydiphenyl ether dianhydride or
2,2'-[4,4'-di(dicarboxyphenyloxy)phenyl]propane dianhydride, and a
diamine such as oxydiamine, para-phenylenediamine,
meta-phenylenediamine or benzophenonediamine.
[0095] Examples of the polyamides include polyamide 6, polyamide 66
and polyamide 610 and the like.
[0096] Examples of the polyesters include polyethylene
terephthalate and polybutylene terephthalate and the like.
[0097] In those cases where the polyanion has substituents,
examples of those substituents include alkyl groups, hydroxyl
groups, amino groups, cyano groups, phenyl groups, phenol groups,
ester groups, alkoxyl groups and carbonyl groups. Considering
factors such as the solubility of the polyanion in solvents, the
heat resistance, and the compatibility of the polyanion with
resins, alkyl groups, hydroxyl groups, phenol groups and ester
groups are preferred.
[0098] Alkyl groups can improve the solubility and dispersibility
of the polyanion in polar solvents or non-polar solvents, and
improve the compatibility with, and dispersibility within resins,
whereas hydroxyl groups can readily form hydrogen bonds with other
hydrogen atoms or the like, thereby improving the solubility within
organic solvents and the compatibility with, dispersibility within,
and adhesion to resins. Moreover, cyano groups and hydroxyphenyl
groups can improve the compatibility with, and solubility within
polar resins, and can also enhance the heat resistance.
[0099] Of the above substituents, alkyl groups, hydroxyl groups,
ester groups and cyano groups are preferred.
[0100] Examples of the alkyl groups include chain-like alkyl groups
such as methyl, ethyl, propyl, butyl, isobutyl, t-butyl, pentyl,
hexyl, octyl, decyl and dodecyl groups, and cycloalkyl groups such
as cyclopropyl, cyclopentyl and cyclohexyl groups. Considering
factors such as the solubility within organic solvents, the
dispersibility within resins, and steric hindrance, alkyl groups of
1 to 12 carbon atoms are particularly preferred.
[0101] Examples of the hydroxyl groups include hydroxyl groups
bonded directly to the main chain of the polyanion, and hydroxyl
groups bonded to the main chain via other functional groups.
Examples of these other functional groups include alkyl groups of 1
to 7 carbon atoms, alkenyl groups of 2 to 7 carbon atoms, amide
groups and imide groups and the like. The hydroxyl groups may be
substituted at either the terminal of these functional groups, or
at non-terminal positions within the functional groups. Of these
groups, hydroxyl groups which are bonded to the terminal of alkyl
groups of 1 to 6 carbon atoms bonded to the main chain are
particularly preferred in terms of the resulting compatibility with
resins and solubility within organic solvents.
[0102] Examples of the ester groups include alkyl ester groups or
aromatic ester groups bonded directly to the main chain of the
polyanion, and alkyl ester groups or aromatic ester groups bonded
to the main chain via other functional groups.
[0103] Examples of the cyano groups include cyano groups bonded
directly to the main chain of the polyanion, cyano groups bonded to
the terminal of an alkyl group of 1 to 7 carbon atoms that is
bonded to the main chain, and cyano groups bonded to the terminal
of an alkenyl group of 2 to 7 carbon atoms that is bonded to the
main chain.
[0104] As the anion groups of the polyanion, any functional groups
that are capable of causing the chemical oxidative doping of the
.pi.-conjugated conductive polymer may be used, but of such
functional groups, from the viewpoints of the ease and stability of
manufacture, mono-substituted sulfate ester groups,
mono-substituted phosphate ester groups, phosphoric acid groups,
carboxyl groups and sulfo groups and the like are preferred.
Moreover, in terms of the doping effect on the .pi.-conjugated
conductive polymer, sulfo groups, mono-substituted sulfate ester
groups and carboxyl groups are particularly desirable.
[0105] Specific examples of the polyanion include polyvinyl
sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid,
polyethyl acrylate sulfonic acid, polybutyl acrylate sulfonic acid,
polyacryl sulfonic acid, polymethacryl sulfonic acid,
poly(2-acrylamide-2-methylpropane sulfonic acid), polyisoprene
sulfonic acid, polyvinyl carboxylic acid, polystyrene carboxylic
acid, polyallyl carboxylic acid, polyacryl carboxylic acid,
polymethacryl carboxylic acid, poly(2-acrylamide-2-methylpropane
carboxylic acid), polyisoprene carboxylic acid and polyacrylic acid
and the like. The polyanion may be either a homopolymer of one of
these polymers, or a copolymer of two or more of the above
polymers.
[0106] Of these, polystyrene sulfonic acid, polyisoprene sulfonic
acid, polyethyl acrylate sulfonic acid and polybutyl acrylate
sulfonic acid are preferred. These polyanions enable greater
increases in the conductivity of the resulting antistatic coating
material, and are able to alleviate thermal decomposition of the
.pi.-conjugated conductive polymer.
[0107] The polymerization degree of the polyanion is preferably
within a range from 10 to 100,000 monomer units, and from the
viewpoints of solvent solubility and conductivity, is even more
preferably within a range from 50 to 10,000 monomer units.
[0108] The quantity of the polyanion within the solid electrolyte
layer 13 is preferably within a range from 0.1 to 10 mol, and even
more preferably from 1 to 7 mol, per 1 mol of the .pi.-conjugated
conductive polymer. If the quantity of the polyanion is less than
0.1 mol, then the doping effect on the .pi.-conjugated conductive
polymer tends to weaken, and the resulting conductivity may be
inadequate. Moreover, the dispersibility and solubility within
solvents also tends to deteriorate, making it difficult to obtain a
uniform dispersion. In contrast, if the quantity of the polyanion
exceeds 10 mol, then the quantity of the .pi.-conjugated conductive
polymer within the solid electrolyte layer 13 is reduced, making it
difficult to achieve a satisfactory degree of conductivity.
[0109] Further, the ratio between the .pi.-conjugated conductive
polymer and the polyanion within the conductive polymer solution is
preferably such that per 100 parts by mass of the polyanion, the
quantity of the .pi.-conjugated conductive polymer is within a
range from 1 to 1,000 parts by mass. If the quantity of the
.pi.-conjugated conductive polymer is less than 1 part by mass,
then the conductivity tends to be insufficient, whereas if the
quantity exceeds 1,000 parts by mass, the solvent solubility tends
to be unsatisfactory.
<Amide Compound>
[0110] The amide compound is a monomolecular compound having an
amide linkage represented by --CO--NH-- (wherein the CO portion
incorporates a double bond) within the molecule. In other words,
examples of the amide compound include compounds that contain
functional groups at both terminals of the above linkage, compounds
in which a cyclic compound is bonded to one of the terminals of the
above linkage, urea, in which the functional groups at both of the
above terminals are hydrogen atoms, and urea derivatives.
[0111] Specific examples of the amide compound include acetamide,
malonamide, succinamide, maleamide, fumaramide, benzamide,
naphthamide, phthalamide, isophthalamide, terephthalamide,
nicotinamide, isonicotinamide, 2-furamide, formamide,
N-methylformamide, propionamide, propiolamide, butylamide,
isobutylamide, methacrylamide, palmitamide, stearylamide, oleamide,
oxamide, glutaramide, adipamide, cinnamamide, glucolamide,
lactamide, glyceramide, tartaramide, citramide, glyoxylamide,
acetoacetamide, dimethylacetamide, benzylamide, anthranylamide,
ethylenediaminetetraacetamide, N-methylacrylamide,
N,N-dimethylaminopropylacrylamide, isopropylacrylamide,
N-hydroxyethylacrylamide, N-hydroxypropylacrylamide,
N-hydroxybutylacrylamide, N-hydroxyethylacetamide,
N-hydroxypropylamide, N-hydroxybutylacetamide, acetamidobenzoic
acid and derivatives thereof, diacetamide, triacetamide,
dibenzamide, tribenzamide, rhodanine, urea, 1-acetyl-2-thiourea,
biuret, butylurea, dibutylurea, 1,3-dimethylurea, 1,3-diethylurea,
and derivatives thereof.
[0112] In order to further enhance the conductivity of the solid
electrolyte layer 13, the amide compound preferably contains one or
more hydroxyl groups. Examples of amide compounds that contain one
or more hydroxyl groups among the compounds exemplified above
include N-hydroxyethylacrylamide, N-hydroxypropylacrylamide,
N-hydroxybutylacrylamide, N-hydroxyethylacetamide,
N-hydroxypropylamide and N-hydroxybutylacetamide. It is thought
that if the amide compound contains a hydroxyl group, then hydrogen
bonding strengthens the interaction with the .pi.-conjugated
conductive polymer and/or the polyanion, thereby further improving
the conductivity.
[0113] Moreover, in terms of the film-forming properties, amide
compounds that also contain a vinyl group and undergo
polymerization, such as N-hydroxyethylacrylamide,
N-hydroxypropylacrylamide and N-hydroxybutylacrylamide, are
particularly desirable.
[0114] The molecular weight of the amide compound is preferably
within a range from 46 to 10,000, is even more preferably from 46
to 5,000, and is most preferably from 46 to 1,000.
[0115] The quantity of the amide compound is preferably within a
range from 1 to 5,000 parts by mass, and even more preferably from
50 to 500 parts by mass, per 100 parts by mass of the combination
of the polyanion and the .pi.-conjugated conductive polymer. If the
quantity of the amide compound is less than 1 part by mass, then
the conductivity and the heat resistance may be inadequate.
Further, if the quantity of the amide compound exceeds 5,000 parts
by mass, then the quantity of the .pi.-conjugated conductive
polymer within the solid electrolyte layer 13 is reduced, making it
difficult to achieve a satisfactory degree of conductivity.
[0116] As the amide compound, a monomolecular compound containing
an imide linkage (hereafter referred to as an imide compound) is
preferred, as it yields a greater improvement in the conductivity.
Examples of the imide compound, described in terms of the molecular
skeleton, include phthalimide and phthalimide derivatives,
succinimide and succinimide derivatives, benzimide and benzimide
derivatives, maleimide and maleimide derivatives, and naphthalimide
and naphthalimide derivatives.
[0117] Further, the imide compounds are classified as either
aliphatic imides or aromatic imides or the like on the basis of the
functional groups at the two terminals, and from the viewpoint of
solubility, aliphatic imides are preferred.
[0118] Moreover, aliphatic imide compounds can be classified into
saturated aliphatic imide compounds, which contain no unsaturated
bonds between the carbon atoms within the molecule, and unsaturated
aliphatic imide compounds, which contain unsaturated bonds between
the carbon atoms within the molecule.
[0119] Saturated aliphatic imide compounds are compounds
represented by the formula: R.sup.1--CO--NH--CO--R.sup.2, wherein
R.sup.1 and R.sup.2 are both saturated hydrocarbon groups. Specific
examples include cyclohexane-1,2-dicarboximide, allantoin,
hydantoin, barbituric acid, alloxan, glutarimide, succinimide,
5-butylhydantoic acid, 5,5-dimethylhydantoin, 1-methylhydantoin,
1,5,5-trimethylhydantoin, 5-hydantoinacetic acid,
N-hydroxy-5-norbornene-2,3-dicarboximide, semicarbazide,
.alpha.,.alpha.-dimethyl-6-methylsuccinimide,
bis[2-(succinimidooxycarbonyloxy)ethyl]sulfone,
.alpha.-methyl-.alpha.-propylsuccinimide and cyclohexylimide.
[0120] Unsaturated aliphatic imide compounds are compounds
represented by the formula: R.sup.1--CO--NH--CO--R.sup.2, wherein
either one of, or both, R.sup.1 and R.sup.2 contain one or more
unsaturated bonds. Specific examples include 1,3-dipropyleneurea,
maleimide, N-methylmaleimide, N-ethylmaleimide, N-hydroxymaleimide,
1,4-bismaleimidobutane, 1,6-bismaleimidohexane,
1,8-bismaleimidooctane and N-carboxheptylmaleimide.
[0121] The molecular weight of the imide compound is preferably
within a range from 60 to 5,000, even more preferably from 70 to
1,000, and is most preferably from 80 to 500.
[0122] The quantity of the amide compound is preferably within a
range from 1 to 10,000 parts by mass, even more preferably from 1
to 5,000 parts by mass, and most preferably from 50 to 500 parts by
mass, per 100 parts by mass of the combination of the polyanion and
the .pi.-conjugated conductive polymer. If the quantity of the
amide compound is less than 1 part by mass, then the conductivity
and the heat resistance may not improve. Further, if the quantity
of the amide compound exceeds 10,000 parts by mass, then the
quantity of the .pi.-conjugated conductive polymer within the solid
electrolyte layer 13 is reduced, making it difficult to achieve a
satisfactory degree of conductivity.
<Compounds Represented by Chemical Formula (1)>
[0123] Compounds represented by Chemical Formula (1) are included
within the amide compound defined above, and are compounds that
include both a vinyl group and an amide linkage (hereafter, a
compound represented by Chemical Formula (1) may be referred to
using the description "compound containing a vinyl group and an
amide linkage").
[0124] In Chemical Formula (1), R.sup.1 and R.sup.2 each
independently represent a hydrogen atom, or an alkyl group or an
alkylene group that may be substituted.
[0125] Examples of the alkyl group include a methyl group, ethyl
group, propyl group, n-butyl group and t-butyl group. Examples of
the alkylene group include an ethylene group, propylene group and
butylene group.
[0126] Specific examples include N-vinylacetamide,
N-vinylpropionamide, N-vinylbutylamide, N-vinyl-isobutylamide,
N-methyl-N-vinylacetamide, N-methyl-N-vinylpropionamide,
N-methyl-N-vinylbutylamide, N-methyl-N-vinyl-isobutylamide,
N-ethyl-N-vinylacetamide, N-ethyl-N-vinylpropionamide,
N,N-divinylacetamide, N,N-divinylpropionamide,
N-benzyl-N-vinylacetamide, N-benzyl-N-vinylpropionamide,
N-(2-propyl)-N-vinylacetamide, and
N-(2-propyl)-N-vinylpropionamide.
[0127] The quantity within the solid electrolyte layer 13 of the
compound containing a vinyl group and an amide linkage is
preferably within a range from 15 to 60% by mass. Provided the
quantity of the compound containing a vinyl group and an amide
linkage is at least 15% by mass, the conductivity of the solid
electrolyte layer 13 can be further increased, and the ESR of the
condenser 10 can be further reduced, whereas provided the quantity
is not more than 60% by mass, the proportion of the .pi.-conjugated
conductive polymer can be maintained at a satisfactory level,
meaning the conductivity can be increased, and the ESR of the
condenser can be lowered even further.
<Ion-Conductive Polymer>
[0128] In order to increase the withstand voltage of the condenser,
an ion-conductive polymer is preferably also included within the
solid electrolyte layer 13. An ion-conductive polymer is a polymer
having a repeating unit that includes an electron-donating region
(a nucleophilic region), and exhibits ion conductivity when an
organic salt or inorganic salt is added. Examples of the
electron-donating region include a cyano group, amino group, amide
group or imide group. Furthermore, amide linkages (--NH--CO--) and
ether linkages (--O--) are also examples of electron-donating
regions.
[0129] Of the various ion-conductive polymers, polymers represented
by Chemical Formula (1) shown below are preferred, as they yield a
superior improvement in the withstand voltage of the condenser
10.
X--(R'O).sub.n--Y (1)
[0130] In the formula (1), R represents one or more moieties
selected from the group consisting of substituted or unsubstituted
alkylene groups, substituted or unsubstituted alkenylene groups,
and substituted or unsubstituted phenylene groups.
[0131] X represents one or more moieties selected from the group
consisting of a hydrogen atom, a hydroxyl group, substituted or
unsubstituted alkyl groups, substituted or unsubstituted alkoxyl
groups, substituted or unsubstituted alkenyl groups, and
substituted or unsubstituted aryl groups.
[0132] Y represents one or more moieties selected from the group
consisting of a hydrogen atom, substituted or unsubstituted alkyl
groups, substituted or unsubstituted alkenyl groups, and
substituted or unsubstituted aryl groups.
[0133] In those cases where X and/or Y is substituted with a
substituent, examples of the substituent include an alkyl group,
hydroxyl group, vinyl group, alkylaryl group, acryloyl group, amino
group or amide group.
[0134] n represents an integer within a range from 2 to 2,000, and
is preferably an integer from 3 to 1,000. If n is more than 2,000,
then the compatibility of the ion-conductive polymer with the
.pi.-conjugated conductive polymer tends to deteriorate, and
forming a uniform matrix becomes difficult.
[0135] Specific examples of the polymer represented by Chemical
Formula (1) include diethylene glycol, triethylene glycol,
oligopolyethylene glycol, triethylene glycol monochlorohydrin,
diethylene glycol monochlorohydrin, oligoethylene glycol
monochlorohydrin, triethylene glycol monobromohydrin, diethylene
glycol monobromohydrin, oligoethylene glycol monobromohydrin,
polyethylene glycol, glycidyl ethers, polyethylene glycol glycidyl
ethers, polyethylene oxide, triethylene glycol dimethyl ether,
tetraethylene glycol dimethyl ether, diethylene glycol dimethyl
ether, diethylene glycol.diethyl ether, diethylene glycol.dibutyl
ether, dipropylene glycol, tripropylene glycol, polypropylene
glycol, polypropylene oxide, polyoxyethylene alkyl ethers,
polyoxyethylene glycerol fatty acid esters, and polyoxyethylene
fatty acid amides.
[0136] Specific examples of ion-conductive polymers other than the
polymers represented by Chemical Formula (1) include
polyvinylpyrrolidone which is formed from monomer units that
contain an amide linkage, polyacrylamide, polyvinylacetamide,
polyamide, polyimide and polyamic acid, which are formed from
monomer units that contain an amide group, as well as
polyacrylonitrile, polysilamine and polyvinyl alcohol.
[0137] The quantity of the ion-conductive polymer is preferably
within a range from 1 to 10,000 parts by mass, and even more
preferably from 50 to 1,500 parts by mass, per 100 parts by mass of
the combination of the .pi.-conjugated conductive polymer and the
polyanion. If the quantity of the ion-conductive polymer is less
than 1 part by mass, then the withstand voltage of the condenser 10
may not increase, whereas if the quantity exceeds 10,000 parts by
mass, then the conductivity of the solid electrolyte layer 13 tends
to deteriorate, and the ESR of the condenser 10 tends to
increase.
[0138] The reason that including an ion-conductive polymer within
the solid electrolyte layer 13 improves the withstand voltage of
the condenser 10 is because the ion-conductive polymer within the
solid electrolyte layer 13 adheres to, or is coordinated to, the
metal oxide that constitutes the dielectric layer 12, thereby
forming a layer of the ion-conductive polymer across a portion of
the surface of the metal oxide. It is thought that this layer
performs the role of a buffer, suppressing the speed of electrons
or ions migrating between the electrodes under the influence of the
electric field. It is surmised that by suppressing the migration
speed of these electrons or ions, damage to the anode 11 or the
cathode 14 caused by the impact of these electrons or ions can be
prevented, thereby enabling the withstand voltage of the condenser
10 to be increased. Accordingly, by lowering the migration speed of
the electrons or ions, damage to the anode 11 or the cathode 14
caused by the impact of these electrons or ions can be prevented,
enabling the withstand voltage of the condenser 10 to be
increased.
[0139] It is thought that defects within the dielectric layer 12
are oxidized and restored when an electric field is applied to the
condenser 10. In the present invention, the ion-conductive polymer
within the solid electrolyte layer 13 acts as an oxygen supply
source during oxidation, and therefore enables ready restoration of
the dielectric layer 12. It is thought that this is also a factor
in improving the withstand voltage of the condenser 10.
<Conductivity Improvers>
[0140] In order to further enhance the conductivity, the solid
electrolyte layer 13 preferably also includes a conductivity
improver. The conductivity improver interacts with either the
.pi.-conjugated conductive polymer or the dopant for the
.pi.-conjugated conductive polymer, thereby improving the
electrical conductance of the .pi.-conjugated conductive
polymer.
[0141] In order to achieve a superior improvement in the
conductivity of the solid electrolyte layer 13, the conductivity
improver is preferably one or more compounds selected from the
group consisting of nitrogen-containing aromatic cyclic compounds,
compounds containing two or more hydroxyl groups, compounds
containing two or more carboxyl groups, compounds containing one or
more hydroxyl groups and one or more carboxyl groups, aromatic
compounds containing a sulfo group and a carboxyl group, compounds
containing an amide group, compounds containing an imide group,
lactam compounds, and compounds containing a glycidyl group.
[0142] Nitrogen-Containing Aromatic Cyclic Compounds
[0143] A nitrogen-containing aromatic compound is a compound having
an aromatic ring that contains at least one nitrogen atom, in which
the nitrogen atom within the aromatic ring has a conjugated
relationship with another atom within the aromatic ring. In order
to achieve this conjugated relationship, the nitrogen atom and the
other atom form an unsaturated bond. Alternatively, the nitrogen
atom may be positioned adjacent to another atom which forms part of
an unsaturated bond, even if the nitrogen atom itself does not form
an unsaturated bond directly with the other atom. This is because
the unshared electron pair on the nitrogen atom is able to form a
pseudo-conjugated relationship with the unsaturated bond formed
between the other atoms.
[0144] The nitrogen-containing aromatic cyclic compound preferably
includes both a nitrogen atom that has a conjugated relationship
with another atom, and a nitrogen atom that is positioned adjacent
to another atom which forms part of an unsaturated bond.
[0145] Examples of this type of nitrogen-containing aromatic cyclic
compound include compounds containing a single nitrogen atom such
as pyridines and derivatives thereof, compounds containing two
nitrogen atoms such as imidazoles and derivatives thereof,
pyrimidines and derivatives thereof, and pyrazines and derivatives
thereof, and compounds containing three nitrogen atoms such as
triazines and derivatives thereof. From the viewpoint of the
solubility within solvents, pyridines and derivatives thereof,
imidazoles and derivatives thereof, and pyrimidines and derivatives
thereof are preferred.
[0146] Further, in the nitrogen-containing aromatic cyclic
compound, a substituent such as an alkyl group, hydroxyl group,
carboxyl group, cyano group, phenyl group, phenol group, ester
group, alkoxy group or carbonyl group may be introduced into the
ring, or an unsubstituted compound may be used. Furthermore, the
ring may also be a polycyclic structure.
[0147] Specific examples of the pyridines and derivatives thereof
include pyridine, 2-methylpyridine, 3-methylpyridine,
4-methylpyridine, 4-ethylpyridine, N-vinylpyridine,
2,4-dimethylpyridine, 2,4,6-trimethylpyridine,
3-cyano-5-methylpyridine, 2-pyridinecarboxylic acid,
6-methyl-2-pyridinecarboxylic acid, 4-pyridinecarboxyaldehyde,
4-aminopyridine, 2,3-diaminopyridine, 2,6-diaminopyridine,
2,6-diamino-4-methylpyridine, 4-hydroxypyridine,
4-pyridinemethanol, 2,6-dihydroxypyridine, 2,6-pyridinedimethanol,
methyl 6-hydroxynicotinate, 2-hydroxy-5-pyridinemethanol, ethyl
6-hydroxynicotinate, 4-pyridinemethanol, 4-pyridineethanol,
2-phenylpyridine, 3-methylquinoline, 3-ethylquinoline, quinolinol,
2,3-cyclopentenopyridine, 2,3-cyclohexanopyridine,
1,2-di(4-pyridyl)ethane, 1,2-di(4-pyridyl)propane,
2-pyridinecarboxyaldehyde, 2-pyridinecarbonitrile,
2,3-pyridinedicarboxylic acid, 2,4-pyridinedicarboxylic acid,
2,5-pyridinedicarboxylic acid, 2,6-pyridinedicarboxylic acid, and
3-pyridinesulfonic acid.
[0148] Specific examples of the imidazoles and derivatives thereof
include imidazole, 2-methylimidazole, 2-propyl imidazole,
2-undecylimidazole, 2-phenylimidazole, N-methylimidazole,
N-vinylimidazole, N-allylimidazole, 1-(2-hydroxyethyl)imidazole,
2-ethyl-4-methylimidazole, 1,2-dimethylimidazole,
1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole,
1-cyanoethyl-2-methylimidazole,
1-cyanoethyl-2-ethyl-4-methylimidazole,
2-phenyl-4,5-dihydroxymethylimidazole, 1-acetylimidazole,
4,5-imidazoledicarboxylic acid, dimethyl
4,5-imidazoledicarboxylate, benzimidazole, 2-aminobenzimidazole,
2-aminobenzimidazole-2-sulfonic acid,
2-amino-1-methylbenzimidazole, 2-hydroxybenzimidazole, and
2-(2-pyridyl)benzimidazole.
[0149] Specific examples of the pyrimidines and derivatives thereof
include 2-amino-4-chloro-6-methylpyrimidine,
2-amino-6-chloro-4-methoxypyrimidine,
2-amino-4,6-dichloropyrimidine, 2-amino-4,6-dihydroxypyrimidine,
2-amino-4,6-dimethylpyrimidine, 2-amino-4,6-dimethoxypyrimidine,
2-aminopyrimidine, 2-amino-4-methylpyrimidine,
4,6-dihydroxypyrimidine, 2,4-dihydroxypyrimidine-5-carboxylic acid,
2,4,6-triaminopyrimidine, 2,4-dimethoxypyrimidine,
2,4,5-trihydroxypyrimidine, and 2,4-pyrimidinediol.
[0150] Examples of the pyrazines and derivatives thereof include
pyrazine, 2-methylpyrazine, 2,5-dimethylpyrazine,
pyrazinecarboxylic acid, 2,3-pyrazinedicarboxylic acid,
5-methylpyrazinecarboxylic acid, pyrazinamide,
5-methylpyrazinamide, 2-cyanopyrazine, aminopyrazine,
3-aminopyrazine-2-carboxylic acid, 2-ethyl-3-methylpyrazine,
2,3-dimethylpyrazine, and 2,3-diethylpyrazine.
[0151] Specific examples of the triazines and derivatives thereof
include 1,3,5-triazine, 2-amino-1,3,5-triazine,
3-amino-1,2,4-triazine, 2,4-diamino-6-phenyl-1,3,5-triazine,
2,4,6-triamino-1,3,5-triazine,
2,4,6-tris(trifluoromethyl)-1,3,5-triazine,
2,4,6-tri-2-pyridyl-1,3,5-triazine,
3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine
disodium, 3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine,
3-(2-pyridyl)-5,6-diphenyl-1,2,4-triazine-.rho.,.rho.'-disulfonic
acid disodium, and 2-hydroxy-4,6-dichloro-1,3,5-triazine.
[0152] Because the nitrogen atom in the nitrogen-containing
aromatic cyclic compound contains an unshared electron pair, a
substituent or a proton can readily coordinate or bond to the
nitrogen atom. When a substituent or a proton coordinates or bonds
to the nitrogen atom, the nitrogen atom tends to adopt a cationic
charge. Because the nitrogen and another atom are conjugated, the
cationic charge produced by the substituent or proton coordinated
or bonded to the nitrogen atom is dispersed throughout the
nitrogen-containing aromatic ring, and exists in a stable
manner.
[0153] For this reason, the nitrogen-containing aromatic cyclic
compound may form a nitrogen-containing aromatic cyclic compound
cation with a substituent introduced at the nitrogen atom. Further,
the cation and an anion may be combined to form a salt. Even in the
form of a salt, the same effect is achieved as that provided by a
non-cationic form of the nitrogen-containing aromatic cyclic
compound.
[0154] Examples of the substituent that can be introduced at the
nitrogen atom of the nitrogen-containing aromatic cyclic compound
include a hydrogen atom, or an alkyl group, hydroxyl group,
carboxyl group, cyano group, phenyl group, phenol group, ester
group, alkoxyl group, or carbonyl group. The same substituents as
those described above can be used.
[0155] The quantity of the nitrogen-containing aromatic cyclic
compound is preferably within a range from 0.1 to 100 mol, and even
more preferably from 0.5 to 30 mol, per 1 mol of anionic group
units within the polyanion. From the viewpoint of the physical
properties and conductivity of the solid electrolyte layer 13 (the
conductive coating), this quantity is most preferably within a
range from 1 to 10 mol. If the quantity of the nitrogen-containing
aromatic cyclic compound is less than 0.1 mol, then the interaction
between the nitrogen-containing aromatic cyclic compound and the
polyanion and .pi.-conjugated conductive polymer tends to weaken,
and the resulting conductivity may be inadequate. In contrast, if
the quantity of the nitrogen-containing aromatic cyclic compound
exceeds 100 mol, then the quantity of the .pi.-conjugated
conductive polymer is reduced, which makes it difficult to achieve
a satisfactory degree of conductivity, and may alter the physical
properties of the solid electrolyte layer 13.
[0156] Compounds Containing Two or More Hydroxyl Groups
[0157] Examples of the compounds containing two or more hydroxyl
groups include: polyhydric aliphatic alcohols such as ethylene
glycol, diethylene glycol, triethylene glycol, propylene glycol,
dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol,
glycerol, diglycerol, D-glucose, D-glucitol, isoprene glycol,
dimethylolpropionic acid, butanediol, 1,5-pentanediol,
1,6-hexanediol, 1,9-nonanediol, neopentyl glycol,
trimethylolethane, trimethylolpropane, pentaerythritol,
dipentaerythritol, thiodiethanol, glucose, polyethylene glycol,
polypropylene glycol, tartaric acid, D-glucaric acid, and
glutaconic acid;
[0158] polymer alcohols such as polyvinyl alcohol, cellulose,
polysaccharides, and sugar alcohols; and
[0159] aromatic compounds such as 1,4-dihydroxybenzene,
1,3-dihydroxybenzene, 2,3-dihydroxy-1-pentadecylbenzene,
2,4-dihydroxyacetophenone, 2,5-dihydroxyacetophenone,
2,4-dihydroxybenzophenone, 2,6-dihydroxybenzophenone,
3,4-dihydroxybenzophenone, 3,5-dihydroxybenzophenone,
2,4'-dihydroxydiphenylsulfone,
2,2',5,5'-tetrahydroxydiphenylsulfone,
3,3',5,5'-tetramethyl-4,4'-dihydroxydiphenylsulfone,
hydroxyquinonecarboxylic acid and salts thereof,
2,3-dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid,
2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid,
3,5-dihydroxybenzoic acid, 1,4-hydroquinonesulfonic acid and salts
thereof, 4,5-hydroxybenzene-1,3-disulfonic acid and salts thereof,
1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene,
2,6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene,
2,3-dihydroxynaphthalene, 1,5-dihydroxynaphthalene-2,6-dicarboxylic
acid, 1,6-dihydroxynaphthalene-2,5-dicarboxylic acid,
1,5-dihydroxynaphthoic acid, phenyl 1,4-dihydroxy-2-naphthoate,
4,5-dihydroxynaphthalene-2,7-disulfonic acid and salts thereof,
1,8-dihydroxy-3,6-naphthalenedisulfonic acid and salts thereof,
6,7-dihydroxy-2-naphthalenesulfonic acid and salts thereof,
1,2,3-trihydroxybenzene (pyrogallol), 1,2,4-trihydroxybenzene,
5-methyl-1,2,3-trihydroxybenzene, 5-ethyl-1,2,3-trihydroxybenzene,
5-propyl-1,2,3-trihydroxybenzene, trihydroxybenzoic acid,
trihydroxyacetophenone, trihydroxybenzophenone,
trihydroxybenzaldehyde, trihydroxyanthraquinone,
2,4,6-trihydroxybenzene, tetrahydroxy-p-benzoquinone,
tetrahydroxyanthraquinone, methyl gallate, ethyl gallate, and
potassium hydroxysulfonate.
[0160] The quantity of the compound containing two or more hydroxyl
groups is preferably within a range from 0.05 to 50 mol, and even
more preferably from 0.3 to 10 mol, per 1 mol of anionic group
units within the polyanion. If the quantity of the compound
containing two or more hydroxyl groups is less than 0.05 mol per 1
mol of anionic group units within the polyanion, then the resulting
conductivity and heat resistance may be inadequate. In contrast, if
the quantity of the compound containing two or more hydroxyl groups
exceeds 50 mol per 1 mol of anionic group units within the
polyanion, then the quantity of the .pi.-conjugated conductive
polymer within the solid electrolyte layer 13 (the conductive
coating) is reduced, which makes it difficult to achieve a
satisfactory degree of conductivity, and may alter the physical
properties of the solid electrolyte layer 13.
[0161] In those cases where a compound containing two or more
hydroxyl groups is included as a conductivity improver, the
conductivity and heat resistance of the solid electrolyte layer 13
(the conductive coating) can be better enhanced for the following
reasons. Namely, because the .pi.-conjugated conductive polymer
within the solid electrolyte layer 13 (the conductive polymer
solution) is in a state of high-level oxidation, heat and the like
can readily cause oxidative degradation of a portion of the
.pi.-conjugated conductive polymer. As a result, it is thought that
radicals are generated, and degradation can then proceed via
radical chain formation. However, it is surmised that the compound
containing two or more hydroxyl groups is able to trap these
radicals via the hydroxyl groups, thereby blocking the formation of
radical chains, inhibiting any degradation, and improving the
conductivity and heat resistance.
[0162] Compounds Containing Two or More Carboxyl Groups
[0163] Examples of the compound containing two or more carboxyl
groups include aliphatic carboxylic acid compounds such as maleic
acid, fumaric acid, itaconic acid, citraconic acid, malonic acid,
1,4-butanedicarboxylic acid, succinic acid, tartaric acid, adipic
acid, D-glucaric acid, glutaconic acid, and citric acid;
[0164] aromatic carboxylic acid compounds containing at least one
carboxyl group bonded to an aromatic ring, such as phthalic acid,
terephthalic acid, isophthalic acid, tetrahydrophthalic anhydride,
5-sulfoisophthalic acid, 5-hydroxyisophthalic acid,
methyltetrahydrophthalic anhydride, 4,4'-oxydiphthalic acid,
biphenyltetracarboxylic dianhydride, benzophenonetetracarboxylic
dianhydride, naphthalenedicarboxylic acid, trimellitic acid, and
pyromellitic acid; as well as diglycolic acid, oxydibutyric acid,
thiodiacetic acid, thiodibutyric acid, iminodiacetic acid, and
iminobutyric acid.
[0165] The quantity of the compound containing two or more carboxyl
groups is preferably within a range from 0.1 to 30 mol, and even
more preferably from 0.3 to 10 mol, per 1 mol of anionic group
units within the polyanion. If the quantity of the compound
containing two or more carboxyl groups is less than 0.1 mol per 1
mol of anionic group units within the polyanion, then the resulting
conductivity and heat resistance may be inadequate. In contrast, if
the quantity of the compound containing two or more carboxyl groups
exceeds 30 mol per 1 mol of anionic group units within the
polyanion, then the quantity of the .pi.-conjugated conductive
polymer within the solid electrolyte layer 13 (the conductive
coating) is reduced, which makes it difficult to achieve a
satisfactory degree of conductivity, and may alter the physical
properties of the solid electrolyte layer 13.
[0166] Compounds Containing One or More Hydroxyl Groups and One or
More Carboxyl Groups
[0167] Examples of the compound containing one or more hydroxyl
groups and one or more carboxyl groups include tartaric acid,
glyceric acid, dimethylolbutanoic acid, dimethylolpropanoic acid,
D-glucaric acid, and glutaconic acid.
[0168] The quantity of the compound containing one or more hydroxyl
groups and one or more carboxyl groups is preferably within a range
from 1 to 5,000 parts by mass, and even more preferably from 50 to
500 parts by mass, per 100 parts by mass of the combination of the
polyanion and the .pi.-conjugated conductive polymer. If the
quantity of the compound containing one or more hydroxyl groups and
one or more carboxyl groups is less than 1 part by mass, then the
resulting conductivity and heat resistance may be inadequate. In
contrast, if the quantity of the compound containing one or more
hydroxyl groups and one or more carboxyl groups exceeds 5,000 parts
by mass, then the quantity of the .pi.-conjugated conductive
polymer within the solid electrolyte layer 13 (the conductive
coating) is reduced, making it difficult to achieve a satisfactory
degree of conductivity.
[0169] Aromatic Compounds Containing a Sulfo Group and a Carboxyl
Group
[0170] The aromatic compound containing a sulfo group and a
carboxyl group is a compound in which an aromatic ring such as a
benzene or naphthalene ring has been substituted with a sulfo group
and a carboxyl group, and examples include 2-sulfobenzoic acid and
salts thereof, 3-sulfobenzoic acid and salts thereof,
3,5-disulfobenzoic acid and salts thereof, 4-sulfophthalic acid and
salts thereof, 5-sulfoisophthalic acid and salts thereof, dimethyl
5-sulfoisophthalate ester and salts thereof, 2-sulfoterephthalic
acid and salts thereof, 5-sulfosalicylic acid and salts thereof,
4-sulfonaphthalene-1,8-dicarboxylic acid,
4-sulfonaphthalene-2,7-dicarboxylic acid,
5-sulfonaphthalene-1,4-dicarboxylic acid, and
3-hydroxy-4-(2-hydroxy-4-sulfo-1-naphthylazo)naphthalene-2-carboxylic
acid.
[0171] The quantity of the aromatic compound containing a sulfo
group and a carboxyl group is preferably within a range from 10 to
10,000 parts by mass, and even more preferably from 50 to 5,000
parts by mass, per 100 parts by mass of the combination of the
.pi.-conjugated conductive polymer and the polyanion. If the
quantity added of the aromatic compound containing a sulfo group
and a carboxyl group is less than the lower limit of the above
range, then the effect achieved by adding the aromatic compound
containing a sulfo group and a carboxyl group tends to diminish,
which is undesirable. In contrast, if the quantity exceeds the
upper limit of the above range, then the conductivity tends to
decrease as a result of the reduction in the concentration of the
.pi.-conjugated conductive polymer, which is also undesirable.
[0172] Lactam Compounds
[0173] A lactam compound is an intramolecular cyclic amide of an
aminocarboxylic acid, and is a compound in which a portion of the
ring can be represented by --CO--NR-- (wherein R is a hydrogen atom
or an arbitrary substituent). One or more of the carbon atoms
within the ring may be unsaturated or substituted for a hetero
atom.
[0174] Examples of the lactam compound include pentano-4-lactam,
4-pentanelactam-5-methyl-2-pyrrolidone, 5-methyl-2-pyrrolidinone,
hexano-6-lactam, and 6-hexanelactam.
[0175] The quantity of the lactam compound is preferably within a
range from 10 to 10,000 parts by mass, and even more preferably
from 50 to 5,000 parts by mass, per 100 parts by mass of the
combination of the .pi.-conjugated conductive polymer and the
polyanion. If the quantity added of the lactam compound is less
than the lower limit of the above range, then the effect achieved
by adding the lactam compound tends to diminish, which is
undesirable. In contrast, if the quantity exceeds the upper limit
of the above range, then the conductivity tends to decrease as a
result of the reduction in the concentration of the .pi.-conjugated
conductive polymer, which is also undesirable.
[0176] Compounds Containing a Glycidyl Group
[0177] Examples of the compound containing a glycidyl group include
glycidyl compounds such as ethyl glycidyl ether, butyl glycidyl
ether, t-butyl glycidyl ether, allyl glycidyl ether, benzyl
glycidyl ether, glycidyl phenyl ether, bisphenol A diglycidyl
ether, glycidyl acrylate, and glycidyl methacrylate.
[0178] The quantity of the compound containing a glycidyl group is
preferably within a range from 10 to 10,000 parts by mass, and even
more preferably from 50 to 5,000 parts by mass, per 100 parts by
mass of the combination of the .pi.-conjugated conductive polymer
and the polyanion. If the quantity added of the compound containing
a glycidyl group is less than the lower limit of the above range,
then the effect achieved by adding the compound containing a
glycidyl group tends to diminish, which is undesirable. In
contrast, if the quantity exceeds the upper limit of the above
range, then the conductivity tends to decrease as a result of the
reduction in the concentration of the .pi.-conjugated conductive
polymer, which is also undesirable.
(Alkaline Compound)
[0179] As the alkaline compound, conventional inorganic alkali
compounds or organic alkali compounds can be used. Examples of
inorganic alkali compounds include sodium hydroxide, potassium
hydroxide, calcium hydroxide and ammonia.
[0180] As the organic alkali compound, nitrogen-containing aromatic
cyclic compounds (aromatic amines), aliphatic amines, and metal
alkoxides and the like can be used favorably.
[0181] Specific examples of the nitrogen-containing aromatic cyclic
compounds include the compounds exemplified above.
[0182] Examples of the aliphatic amine compounds include
ethylamine, n-octylamine, diethylamine, diisobutylamine,
methylethylamine, trimethylamine, triethylamine, allylamine,
2-ethylaminoethanol, 2,2'-iminodiethanol, and
N-ethylethylenediamine.
[0183] Examples of the metal alkoxides include sodium alkoxides
such as sodium methoxide and sodium ethoxide, as well as potassium
alkoxides and calcium alkoxides.
[0184] Of these alkaline compounds, nitrogen-containing aromatic
cyclic compounds are preferred. This is because nitrogen-containing
aromatic cyclic compounds not only prevent de-doping of the
polyanion, but also enable a superior improvement in the
conductivity.
[0185] The pH (25.degree. C.) of the conductive polymer solution is
preferably adjusted by the alkaline compound to a value within a
range from 3 to 13, and even more preferably from 5 to 11. Provided
the pH of the conductive polymer solution is at least 3, the
corrosive properties are able to be suppressed. However, if the pH
exceeds 13, then the conductivity of the .pi.-conjugated conductive
polymer tends to deteriorate, which is undesirable.
[0186] Organic Solvent
[0187] Furthermore, if a portion of the organic solvent remains
within the solid electrolyte layer 13, it can also function as a
conductivity improver. Examples of organic solvents that can
function as a conductivity improver include polar solvents such as
N-methyl-2-pyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, dimethylsulfoxide,
hexamethylenephosphortriamide, N-vinylpyrrolidone, N-vinylformamide
and N-vinylacetamide; phenols such as cresol, phenol and xylenol;
polyhydric aliphatic alcohols such as ethylene glycol, diethylene
glycol, triethylene glycol, propylene glycol, dipropylene glycol,
1,3-butylene glycol, 1,4-butylene glycol, glycerol, diglycerol,
D-glucose, D-glucitol, isoprene glycol, butanediol,
1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and neopentyl
glycol; carbonate compounds such as ethylene carbonate and
propylene carbonate; ether compounds such as dioxane and diethyl
ether; chain-like ethers such as dialkyl ethers, propylene glycol
dialkyl ethers, polyethylene glycol dialkyl ethers, and
polypropylene glycol dialkyl ethers; heterocyclic compounds such as
3-methyl-2-oxazolidinone; and nitrile compounds such as
acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile,
and benzonitrile. These solvents may be used either alone, or as
mixtures containing two or more different solvents.
[0188] The quantity of the organic solvent is preferably within a
range from 10 to 100,000 parts by mass, and even more preferably
from 50 to 10,000 parts by mass, per 100 parts by mass of the
combination of the .pi.-conjugated conductive polymer and the
polyanion.
[0189] These types of conductivity improvers are able to bring
molecules of the .pi.-conjugated conductive polymer closer
together, either by forming hydrogen bonds between the polyanion
and the .pi.-conjugated conductive polymer, or by generating
interactions between individual molecules of these compounds. It is
thought that, as a result, the energy required for the electrical
conductance phenomenon known as hopping to occur between molecules
of the .pi.-conjugated conductive polymer is reduced, thereby
reducing the overall electrical resistance and improving the
conductivity.
[0190] <Silane Coupling Agent>
[0191] The silane coupling agent is a compound represented by
Chemical Formula (1) shown below.
X.sub.3--Si--Y Chemical Formula (1)
[0192] In the formula (1), X represents an alkoxyl group or a
halogen atom. Examples of the alkoxy group include a methoxy group,
ethoxy group, propoxy group or butoxy group. Examples of the
halogen atom include a fluorine atom, chlorine atom, bromine atom
or iodine atom.
[0193] Y represents one or more groups selected from the group
consisting of substituted or unsubstituted vinyl groups, epoxy
groups, styryl groups, methacryloxy groups, acryloxy groups, amino
groups, ureido groups, chloropropyl groups, mercapto groups,
sulfide groups and isocyanate groups.
[0194] Specific examples of the silane coupling agent include
vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane,
2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
3-glycidoxypropyltrimethoxysilane,
3-glycidoxypropylmethyldiethoxysilane,
3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane,
3-methacryloxypropylmethyldimethoxysilane,
3-methacryloxypropyltrimethoxysilane,
3-methacryloxypropylmethyldiethoxysilane,
3-methacryloxypropyltriethoxysilane,
3-acryloxypropyltrimethoxysilane,
N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane,
N-2-(aminoethyl)-3-aminopropyltriethoxysilane,
N-2-(aminoethyl)-3-aminopropyltrimethoxysilane,
3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,
3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine,
N-phenyl-3-aminopropyltrimethoxysilane,
N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane
hydrochloride, 3-ureidopropyltriethoxysilane,
3-chloropropyltrimethoxysilane,
3-mercaptopropylmethyldimethoxysilane,
3-mercaptopropyltrimethoxysilane,
bis(triethoxysilylpropyl)tetrasulfide, and
3-isocyanatopropyltriethoxysilane.
[0195] The quantity of the silane coupling agent is preferably
within a range from 1 to 10,000 parts by mass, and even more
preferably from 50 to 1,500 parts by mass, per 100 parts by mass of
the combined mass of the .pi.-conjugated conductive polymer and the
polyanion. If the quantity of the silane coupling agent is less
than 1 part by mass per 100 parts by mass of the combined mass of
the .pi.-conjugated conductive polymer and the polyanion, then the
withstand voltage may not be able to be increased, whereas if the
quantity exceeds 10,000 parts by mass, the conductivity may
decrease and the ESR may increase.
<Dopant>
[0196] In order to further improve the conductivity of the
.pi.-conjugated conductive polymer, the solid electrolyte layer 13
(the conductive polymer solution) may also include other dopants
other than the polyanion.
[0197] As these other dopants, halogen compounds, Lewis acids,
protic acids, alkaline earth metals and quaternary amine compounds
and the like can be used, and specific examples include organic
acids such as organic carboxylic acids and organic sulfonic acids,
as well as organic cyano compounds, fullerene, fullerene hydride,
fullerene hydroxide, fullerene carboxylate and fullerene sulfonate
and the like.
[0198] The quantity of the dopant compound is preferably within a
range from 10 to 10,000 molar parts, and even more preferably from
30 to 3,000 molar parts, per 100 molar parts of the .pi.-conjugated
conductive polymer. If the quantity added of the dopant compound is
less than the lower limit of the above range, then the effect
achieved by adding the dopant compound tends to diminish, which is
undesirable. In contrast, if the quantity exceeds the upper limit
of the above range, then the conductivity tends to decrease as a
result of the reduction in the concentration of the .pi.-conjugated
conductive polymer, which is also undesirable.
[0199] Specific examples of the organic acids include organic
sulfonic acid compounds such as alkylbenzenesulfonic acids,
alkylnaphthalenesulfonic acids, alkylnaphthalenedisulfonic acids,
naphthalenesulfonic acid-formalin polycondensates, melaminesulfonic
acid-formalin polycondensates, naphthalenedisulfonic acid,
naphthalenetrisulfonic acid, dinaphthylmethanedisulfonic acid,
anthraquinonesulfonic acid, anthraquinonedisulfonic acid,
anthracenesulfonic acid and pyrenesulfonic acid; and organic
carboxylic acid compounds such as acetic acid, oxalic acid, benzoic
acid, phthalic acid, maleic acid, fumaric acid, and malonic acid.
Further, metal salts of these organic acids may also be used.
[0200] As the organic cyano compound, compounds having two or more
cyano groups bonded to conjugated bonds can be used. Specific
examples include tetracyanoethylene, tetracyanoethylene oxide,
tetracyanobenzene, dichlorodicyanobenzoquinone (DDQ),
tetracyanoquinodimethane, and tetracyanoazanaphthalene.
<Binder Resin>
[0201] In order to regulate the film-forming properties and film
strength and the like, the solid electrolyte layer 13 (the
conductive polymer solution) may also include a binder resin.
[0202] There are no particular restrictions on the binder resin,
provided it is compatible with, or mixable and dispersible within,
the .pi.-conjugated conductive polymer or the polyanion, and either
thermosetting resins or thermoplastic resins may be used. Examples
of the binder resin include polyesters such as polyethylene
terephthalate, polybutylene terephthalate and polyethylene
naphthalate, polyimides such as polyimide and polyamideimide,
polyamides such as polyamide 6, polyamide 66, polyamide 12 and
polyamide 11, fluororesins such as polyvinylidene fluoride,
polyvinyl fluoride, polytetrafluoroethylene,
ethylene-tetrafluoroethylene copolymer, and
polychlorotrifluoroethylene, vinyl resins such as polyvinyl
alcohol, polyvinyl ether, polyvinyl butyral, polyvinyl acetate and
polyvinyl chloride, as well as epoxy resins, xylene resins, aramid
resins, polyurethane, polyurea, melamine resins, phenolic resins,
polyethers, acrylic-based resins, and copolymers thereof.
[0203] The quantity of the binder resin is preferably within a
range from 1 to 50,000 parts by mass, and even more preferably from
10 to 1,000 parts by mass, per 100 parts by mass of the combination
of the .pi.-conjugated conductive polymer and the polyanion. If the
quantity added of the binder resin is less than the lower limit of
the above range, then the effect achieved by adding the binder
resin tends to diminish, which is undesirable. In contrast, if the
quantity exceeds the upper limit of the above range, then the
conductivity tends to decrease as a result of the reduction in the
concentration of the .pi.-conjugated conductive polymer, which is
also undesirable.
[0204] Furthermore, instead of adding an aforementioned binder
resin, a precursor compound or monomer that gives rise to a binder
resin may be added to the conductive polymer solution. The binder
resin can then be formed by polymerizing the precursor compound or
monomer.
(Cathode)
[0205] The cathode 14 is formed, for example, from a layer of
carbon, silver or aluminum or the like. In those cases where the
cathode 14 is formed from carbon or silver or the like, it can be
formed from a conductive paste containing a conductor such as
carbon or silver. Further, in those cases where the cathode 14 is
formed from aluminum, it may be formed using an aluminum foil.
[0206] In the condenser 10, a separator may be provided between the
dielectric layer 12 and the solid electrolyte layer 13 as
required.
[0207] Because it contains an amide compound, the solid electrolyte
layer 13 used in forming the condenser 10 has a high degree of
conductivity. As a result, the ESR of the condenser 10 can be
lowered. Further, it is thought that in those cases where the amide
compound is a compound containing a vinyl group and an amide
linkage, interaction in the solid electrolyte layer 13 between the
compound containing a vinyl group and an amide linkage and the
anionic groups within the polyanion is facilitated, and this
interaction enables molecules of the polyanion to be drawn closer
together. As a result, molecules of the .pi.-conjugated conductive
polymer, which are adsorbed to the polyanion by doping, are also
drawn closer together. It is surmised that this enables a reduction
in the energy required for the electrical conductance phenomenon
known as hopping to occur between molecules of the .pi.-conjugated
conductive polymer, thereby increasing the conductivity. By
increasing the conductivity of the solid electrolyte layer 13, the
ESR of the condenser 10 can be reduced. Further, it is thought that
the heat resistance also improves as a result of drawing the
molecules of the .pi.-conjugated conductive polymer closer
together.
[0208] In those cases where the solid electrolyte layer 13 of the
condenser 10 includes a silane coupling agent, the solid
electrolyte layer 13 can be bonded strongly to the dielectric layer
12. As a result, defects are less likely to develop within the
dielectric layer 12, and the withstand voltage of the condenser 10
can be increased even if the thickness of the dielectric layer 12
is reduced. In addition, even though the solid electrolyte layer 13
includes the polyanion and silane coupling agent that exhibit no
conductivity, because the layer also includes a conductivity
improver, the conductivity is comparatively high, meaning the ESR
of the condenser 10 is at a level that is low enough to enable
practical application. Moreover, the condenser 10 also has a
satisfactory capacitance.
[0209] In those cases where the condenser 10 includes, between the
dielectric layer 12 and the solid electrolyte layer 13, an
intermediate layer 16 that contains a low-thermal expansion polymer
and has a coefficient of thermal expansion that is little different
from the coefficient of thermal expansion for the dielectric layer
12, when the structure is exposed to thermal stress during
manufacture of the condenser, the intermediate layer 16 expands at
substantially the same rate as the dielectric layer 12. As a
result, even if exposed to thermal stress, defects are unlikely to
develop within the intermediate layer 16, and shorting between the
anode 11 and the solid electrolyte layer 13 can be prevented.
(Process for Manufacturing Conductive Polymer Solution)
[0210] Next is a description of an example of a process for
manufacturing the conductive polymer solution.
[0211] In this process for manufacturing the conductive polymer
solution, first, a precursor monomer that forms the .pi.-conjugated
conductive polymer is subjected to a chemical oxidative
polymerization within a solvent and in the presence of the
polyanion, thereby forming a complex between the .pi.-conjugated
conductive polymer and the polyanion.
[0212] Subsequently, the conductivity improver and the alkaline
compound are added to the solution containing the complex, thus
forming the conductive polymer solution. There are no particular
restrictions on the order in which the conductivity improver and
the alkaline compound are added, and either may be added first.
Furthermore, an additional quantity of the solvent may also be
added afterwards.
[0213] The conductivity improver included within the above
conductive polymer solution is able to bring molecules of the
.pi.-conjugated conductive polymer closer together, either by
forming hydrogen bonds between the polyanion and the
.pi.-conjugated conductive polymer, or by generating interactions
between individual molecules of these compounds. It is thought
that, as a result, the energy required for the electrical
conductance phenomenon known as hopping to occur between molecules
of the .pi.-conjugated conductive polymer is reduced, thereby
reducing the overall electrical resistance and improving the
conductivity. Furthermore, because the conductive polymer solution
also includes an alkaline compound, the acidity is reduced, thereby
reducing the corrosive properties.
<Conductive Coating>
[0214] A conductive coating of the present invention is formed by
applying, and then drying, the conductive polymer solution
described above.
[0215] Examples of the method used for applying the conductive
polymer solution include conventional coating, dipping and spraying
techniques.
[0216] Examples of the coating target object to which the
conductive polymer solution is applied include a glass plate,
plastic film, metal layer, or metal oxide layer.
[0217] Examples of the method used for drying the conductive
polymer solution following application include drying methods such
as blow drying at room temperature, or drying using a hot air dryer
or far infrared dryer. From the viewpoint of improving the film
formation efficiency, a method that uses a hot air dryer or far
infrared dryer or the like is preferred. By using this type of
drying method, the volatile component within the conductive polymer
solution is removed, yielding a conductive coating.
[0218] Because the conductive coating described above is formed by
applying, and then drying, the conductive polymer solution
described above, the coating exhibits a high degree of conductivity
and minimal corrosive properties.
<Process for Manufacturing Condenser>
[0219] Next is a description of a process for manufacturing the
condenser 10.
[0220] In a process for manufacturing the condenser 10 according to
one embodiment of the present invention, a conductive polymer
solution is first applied and adhered to the surface of a
dielectric layer 12 of a condenser intermediate having an anode 11
and a dielectric layer 12 composed of an oxide film formed by
oxidizing the surface of the anode 11. The conductive polymer
solution used in this step contains, as essential components, the
.pi.-conjugated conductive polymer, the polyanion, either an amide
compound or a combination of a conductivity improver and a silane
coupling agent, and a solvent.
[0221] Furthermore, in a process for manufacturing the condenser 10
according to another embodiment of the present invention, a
low-thermal expansion polymer solution is applied to the surface of
the dielectric layer 12 to form an intermediate layer 16, and a
conductive polymer solution is then applied to the surface of the
intermediate layer 16 to form the solid electrolyte layer 13. The
low-thermal expansion polymer solution used in forming the
intermediate layer 16 is prepared by dissolving a low-thermal
expansion polymer described above in a solvent. The concentration
of the low-thermal expansion polymer solution is preferably within
a range from 0.01 to 5% by mass, and is even more preferably from
0.01 to 0.5% by mass. Examples of the method used for applying the
low-thermal expansion polymer solution include conventional
coating, dipping and spraying techniques. As the drying method,
conventional techniques such as hot air drying may be used.
[0222] There are no particular restrictions on the solvent used,
and examples include water and/or an organic solvent. In terms of
ensuring a higher level of conductivity for the resulting
conductive coating, a solvent composed of water and an organic
solvent is preferred. In other words, the organic solvents listed
below may improve the conductivity.
[0223] Specific examples of the organic solvent include polar
solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, dimethylsulfoxide,
hexamethylenephosphortriamide, N-vinylpyrrolidone, N-vinylformamide
and N-vinylacetamide; phenols such as cresol, phenol and xylenol;
polyhydric aliphatic alcohols such as ethylene glycol, diethylene
glycol, triethylene glycol, propylene glycol, dipropylene glycol,
1,3-butylene glycol, 1,4-butylene glycol, glycerol, diglycerol,
D-glucose, D-glucitol, isoprene glycol, butanediol,
1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and neopentyl
glycol; ketones such as acetone and methyl ethyl ketone;
hydrocarbons such as hexane, benzene and toluene; carboxylic acids
such as formic acid and acetic acid; carbonate compounds such as
ethylene carbonate and propylene carbonate; ether compounds such as
dioxane, diethyl ether, triethylene glycol dimethyl ether,
tetraethylene glycol dimethyl ether, diethylene glycol dimethyl
ether, diethylene glycol diethyl ether, and diethylene glycol
dibutyl ether; chain-like ether compounds such as dialkyl ethers,
propylene glycol dialkyl ethers, polyethylene glycol dialkyl
ethers, and polypropylene glycol dialkyl ethers; heterocyclic
compounds such as 3-methyl-2-oxazolidinone; and nitrile compounds
such as acetonitrile, glutarodinitrile, methoxyacetonitrile,
propionitrile, and benzonitrile. These solvents may be used either
alone, or as mixtures containing two or more different
solvents.
[0224] Of these, from the viewpoint of simplifying the process,
alcohol-based solvents having a low boiling point, and
environmentally friendly water are preferred.
[0225] Moreover, in terms of ensuring a superior improvement in the
conductivity and facilitating ready control of the drying rate, a
mixed solvent of water and an organic solvent having a boiling
point of 100.degree. C. or higher at a pressure of 0.1 MPa is
particularly desirable.
[0226] Examples of the organic solvent having a boiling point of
100.degree. C. or higher at a pressure of 0.1 MPa, selected from
the solvents exemplified above, include polar solvents such as
N-methyl-2-pyrrolidone, N,N-dimethylformamide,
N,N-dimethylacetamide, dimethylsulfoxide,
hexamethylenephosphortriamide, N-vinylpyrrolidone, N-vinylformamide
and N-vinylacetamide; and polyhydric alcohols such as ethylene
glycol, diethylene glycol, triethylene glycol, propylene glycol,
dipropylene glycol, 1,3-butylene glycol, 1,4-butylene glycol,
glycerol, diglycerol, D-glucose, D-glucitol, isoprene glycol,
butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, and
neopentyl glycol. These solvents may be used either alone, or as
mixtures containing two or more different solvents.
[0227] The quantity of the organic solvent is preferably within a
range from 1 to 10,000 parts by mass, and even more preferably from
50 to 3,000 parts by mass, per 100 parts by mass of the combination
of the polyanion and the .pi.-conjugated conductive polymer.
[0228] If required, other additives may be added to the conductive
polymer solution to improve properties such as the coating
properties and stability of the conductive polymer solution, the
adhesiveness of the solution to substrates, and the properties of
the generated solid electrolyte layer 13 (the conductive coating).
There are no particular restrictions on these additives, provided
they are able to be mixed with the .pi.-conjugated conductive
polymer and the polyanion, and examples of additives that can be
used include surfactants, antifoaming agents, coupling agents, and
antioxidants.
[0229] Examples of the surfactants include anionic surfactants such
as carboxylates, sulfonates, sulfates and phosphates; cationic
surfactants such as amine salts and quaternary ammonium salts;
amphoteric surfactants such as carboxybetaines, aminocarboxylates,
and imidazolium betaines; and non-ionic surfactants such as
polyoxyethylene alkyl ethers, polyoxyethylene glycerol fatty acid
esters, ethylene glycol fatty acid esters, and polyoxyethylene
fatty acid amides.
[0230] Examples of the antifoaming agents include silicone resins,
polydimethylsiloxane, and silicone resins.
[0231] Examples of the coupling agents include silane coupling
agents having a vinyl group, amino group, epoxy group or methacryl
group.
[0232] Examples of the antioxidants include phenol-based
antioxidants, amine-based antioxidants, phosphorus-based
antioxidants, sulfur-based antioxidants, sugars, and vitamins.
[0233] The conductive polymer solution preferably has a pH at
25.degree. C. within a range from 3 to 13, and even more preferably
from 5 to 11. Provided the pH of the conductive polymer solution is
at least 3, corrosion of the dielectric layer 12 caused by the
conductive polymer solution is able to be prevented. However, if
the pH exceeds 13, then the conductivity of the .pi.-conjugated
conductive polymer tends to deteriorate, which is undesirable.
[0234] An alkaline compound may be added to ensure that the pH of
the conductive polymer solution is within the range from 3 to 13.
As the alkaline compound, conventional inorganic alkali compounds
or organic alkali compounds can be used. Examples of inorganic
alkali compounds include sodium hydroxide, potassium hydroxide,
calcium hydroxide and ammonia.
[0235] As the organic alkali compound, nitrogen-containing aromatic
cyclic compounds (aromatic amines), aliphatic amines, and metal
alkoxides and the like can be used favorably.
[0236] Examples of the nitrogen-containing aromatic cyclic
compounds include the compounds exemplified above.
[0237] Examples of the aliphatic amine compounds include aliphatic
amines such as dimethylamine and diethylamine, aromatic amine
compounds such as imidazole, 2-methylimidazole,
1-hydroxyethylimidazole, 2,6-pyridinedimethanol, and
2-pyridinecarboxylic acid, sodium alkoxides such as sodium
methoxide and sodium ethoxide, and metal alkoxides such as
potassium alkoxides and calcium alkoxides.
[0238] Further, methods of adjusting the pH to a value within the
range from 3 to 13 include methods that involve either esterifying
or amidizing the acid contained within the conductive polymer
solution.
[0239] In order to obtain the conductive polymer solution, first, a
precursor monomer that forms the .pi.-conjugated conductive polymer
is added to a solvent in the presence of the polyanion.
Subsequently, an oxidant is added, the precursor monomer is
polymerized, and any excess oxidant and precursor monomer is then
removed, thus yielding a solution containing a complex formed
between the .pi.-conjugated conductive polymer and the
polyanion.
[0240] Examples of the precursor monomer used include pyrroles and
derivatives thereof, thiophenes and derivatives thereof, and
anilines and derivatives thereof.
[0241] As the oxidant, any compound capable of oxidizing the
precursor monomer to form the .pi.-conjugated conductive polymer
can be used, and examples include peroxodisulfates such as ammonium
peroxodisulfate (ammonium persulfate), sodium peroxodisulfate
(sodium persulfate) and potassium peroxodisulfate (potassium
persulfate), transition metal compounds such as ferric chloride,
ferric sulfate, ferric nitrate and cupric chloride, metal halide
compounds such as boron trifluoride and aluminum chloride, metal
oxides such as silver oxide and cesium oxide, peroxides such as
hydrogen peroxide and ozone, organic peroxides such as benzoyl
peroxide, and oxygen and the like.
[0242] As the solvent, the same solvents as those used for the
low-thermal expansion polymer solution can be used.
[0243] Subsequently, to the solution containing the complex are
added the amide compound or the combination of the conductivity
improver and the silane coupling agent, and if required, any of the
optional components such as the ion-conductive polymer and the
alkaline compound, thus forming the conductive polymer
solution.
[0244] Examples of the method used for adhering the conductive
polymer solution to the surface of the dielectric layer 12 include
conventional coating, dipping and spraying techniques.
[0245] Subsequently, the conductive polymer solution adhered to the
dielectric layer 12 is dried, thus forming the solid electrolyte
layer 13. Examples of the drying method include conventional
techniques such as room temperature drying, hot air drying, and far
infrared drying.
[0246] In the solid electrolyte layer 13, the .pi.-conjugated
conductive polymer is usually formed as particles having a particle
size within a range from 1 to 500 nm. As a result, the
.pi.-conjugated conductive polymer is unable to penetrate down to
the deepest portions of fine voids within the surface of the
dielectric layer 12, meaning it can sometimes be difficult to
extract the desired capacitance. Accordingly, following formation
of the solid electrolyte layer 13, the layer is preferably immersed
within an electrolyte solution, when required, in order to
supplement the capacitance.
[0247] There are no particular restrictions on this electrolyte
solution, provided it exhibits a high degree of conductivity, and
the solution can be prepared by dissolving a conventional
electrolyte in a conventional solvent.
[0248] Examples of the solvent used in the electrolyte solution
include alcohol-based solvents such as ethylene glycol, diethylene
glycol, propylene glycol, 1,4-butanediol and glycerol,
lactone-based solvents such as .gamma.-butyrolactone,
.gamma.-valerolactone and .delta.-valerolactone, amide solvents
such as N-methylformamide, N,N-dimethylformamide, N-methylacetamide
and N-methylpyrrolidinone, nitrile solvents such as acetonitrile
and 3-methoxypropionitrile, and water and the like.
[0249] Examples of the electrolyte include an anion component
composed of an organic acid such as adipic acid, glutaric acid,
succinic acid, benzoic acid, isophthalic acid, phthalic acid,
terephthalic acid, maleic acid, toluic acid, enanthic acid, malonic
acid, formic acid, a decandicarboxylic acid such as
1,6-decanedicarboxylic acid or 5,6-decanedicarboxylic acid, an
octanedicarboxylic acid such as 1,7-octanedicarboxylic acid,
azelaic acid or sebacic acid, or an inorganic acid such as boric
acid, a boric acid polyhydric alcohol complex compound obtained
from boric acid and a polyhydric alcohol, phosphoric acid, carbonic
acid or silicic acid; and a cation component such as a primary
amine (such as methylamine, ethylamine, propylamine, butylamine or
ethylenediamine), a secondary amine (such as dimethylamine,
diethylamine, dipropylamine, methylethylamine or diphenylamine), a
tertiary amine (such as trimethylamine, triethylamine,
tripropylamine, triphenylamine,
1,8-diazabicyclo(5,4,0)-undecene-7), or a tetraalkylammonium (such
as tetramethylammonium, tetraethylammonium, tetrapropylammonium,
tetrabutylammonium, methyltriethylammonium or
dimethyldiethylammonium).
[0250] Subsequently, a carbon paste or a silver paste or the like
is applied to the solid electrolyte layer 13, thereby forming the
cathode 14 and completing the condenser 10.
[0251] The process for manufacturing a condenser 10 described above
is a process in which a conductive polymer solution containing a
.pi.-conjugated conductive polymer is adhered to the dielectric
layer 12, and the adhered conductive polymer solution is then dried
to form a solid electrolyte layer 13, and therefore the solution is
able to penetrate readily into any fine voids within the dielectric
layer 12. As a result, a high capacitance can be extracted with
relative ease.
[0252] Furthermore, when the solid electrolyte layer 13 is formed
using a conductive polymer solution containing an amide compound,
the conductivity of the solid electrolyte layer 13 is high, and the
ESR of the condenser 10 can be reduced. Further, because the solid
electrolyte layer 13 exhibits a high level of heat resistance, the
heat resistance of the condenser 10 can also be enhanced.
[0253] On the other hand, when the conductive polymer solution
contains a silane coupling agent, the dielectric layer 12 to which
the conductive polymer solution is applied and the solid
electrolyte layer 13 formed from the conductive polymer solution
can be bonded strongly together, and as a result, the withstand
voltage of the condenser 10 can be increased even if the thickness
of the dielectric layer 12 is reduced. Further, because this
manufacturing process is not a process in which the solid
electrolyte layer 13 is formed on top of the dielectric layer 12
using an electrolytic polymerization method or a chemical oxidative
polymerization method, and moreover, the conductive polymer
solution also includes a conductivity improver, the conductivity of
the solid electrolyte layer 13 can be improved, and the ESR of the
condenser 10 can be reduced to a level that is practically
applicable. Furthermore, a satisfactory electrostatic capacitance
can also be ensured for the condenser 10.
[0254] In the process for manufacturing a condenser 10 described
above, a low-thermal expansion polymer solution is applied to the
surface of the dielectric layer 12 to form an intermediate layer
16, and the solid electrolyte layer 13 is then formed on the
surface of this intermediate layer 16, and as a result, shorting
between the anode 11 and the solid electrolyte layer 13 caused by
thermal stress can be suppressed, enabling the failure rate to be
reduced. Further, because the solid electrolyte layer 13 is formed
by applying, and then drying, a conductive polymer solution
containing an already polymerized .pi.-conjugated conductive
polymer, the process is simple, particularly suitable for mass
production, and low-cost.
[0255] The process for manufacturing a condenser according to the
present invention is not limited to the embodiments described
above. For example, as shown in FIG. 3, the condenser of the
present invention may, if required, include a separator 15 provided
between the dielectric layer 12 and the cathode 14. An example of a
condenser that includes a separator 15 provided between the
dielectric layer 12 and the cathode 14 is a wound condenser.
[0256] As the separator 15, a sheet (including a non-woven fabric)
composed of a polyvinyl alcohol, polyester, polyethylene,
polystyrene, polypropylene, polyimide, polyamide or a
polyvinylidene fluoride or the like, or a non-woven sheet of glass
fiber or the like can be used.
[0257] The density of the separator 15 is preferably within a range
from 0.1 to 1 g/cm.sup.3, and is even more preferably from 0.2 to
0.8 g/cm.sup.3.
[0258] In those cases where a separator 15 is provided, a method
can be employed in which a carbon paste or silver paste is
impregnated into the separator 15 to form the cathode 14.
[0259] Furthermore, in the condenser of the present invention, an
electrolyte solution can be used if required. By using an
electrolyte solution in combination with the condenser of the
present invention, the capacitance can be increased even more
simply. There are no particular restrictions on the electrolyte
solution, provided it exhibits a high degree of electrical
conductivity, and the solution can be prepared by dissolving a
conventional electrolyte in a conventional electrolyte solvent.
[0260] Examples of the electrolyte solvent include alcohol-based
solvents such as ethylene glycol, diethylene glycol, propylene
glycol, 1,4-butanediol and glycerol, lactone-based solvents such as
.gamma.-butyrolactone, .gamma.-valerolactone and
.delta.-valerolactone, amide solvents such as N-methylformamide,
N,N-dimethylformamide, N-methylacetamide and N-methylpyrrolidinone,
nitrile solvents such as acetonitrile and 3-methoxypropionitrile,
and water and the like.
[0261] Examples of the electrolyte include an anion component
composed of an organic acid such as adipic acid, glutaric acid,
succinic acid, benzoic acid, isophthalic acid, phthalic acid,
terephthalic acid, maleic acid, toluic acid, enanthic acid, malonic
acid, formic acid, a decandicarboxylic acid such as
1,6-decanedicarboxylic acid or 5,6-decanedicarboxylic acid, an
octanedicarboxylic acid such as 1,7-octanedicarboxylic acid,
azelaic acid or sebacic acid, or an inorganic acid such as boric
acid, a boric acid polyhydric alcohol complex compound obtained
from boric acid and a polyhydric alcohol, phosphoric acid, carbonic
acid or silicic acid; and a cation component such as a primary
amine (such as methylamine, ethylamine, propylamine, butylamine or
ethylenediamine), a secondary amine (such as dimethylamine,
diethylamine, dipropylamine, methylethylamine or diphenylamine), a
tertiary amine (such as trimethylamine, triethylamine,
tripropylamine, triphenylamine,
1,8-diazabicyclo(5,4,0)-undecene-7), or a tetraalkylammonium (such
as tetramethylammonium, tetraethylammonium, tetrapropylammonium,
tetrabutylammonium, methyltriethylammonium or
dimethyldiethylammonium).
[0262] Furthermore, in those cases where the solid electrolyte
layer is utilized as the cathode, a separate cathode need not
necessarily be provided. In such cases, the present invention
enables damage to the anode to be prevented, and enables the
withstand voltage to be increased.
EXAMPLES
[0263] A more detailed description of the present invention is
presented below based on a series of examples. In the following
examples, pH values refer to values measured at 25.degree. C.
Example 1
(1) Preparation of Conductive Polymer Solution
[0264] 14.2 g (0.1 mol) of 3,4-ethylenedioxythiophene, and a
solution prepared by dissolving 27.5 g (0.15 mol) of a
polystyrenesulfonic acid (molecular weight: about 150,000) in 2,000
ml of ion-exchanged water were mixed at 20.degree. C.
[0265] With the obtained mixed solution undergoing constant
stirring at 20.degree. C., a solution containing 29.64 g (0.13 mol)
of ammonium persulfate dissolved in 200 ml of ion-exchanged water,
and 8.0 g (0.02 mol) of a ferric sulfate oxidation catalyst
solution were added, and the resulting mixture was then stirred and
allowed to react for 3 hours.
[0266] The resulting reaction mixture was subjected to a dialysis
treatment, thereby removing the unreacted monomer, oxidant and
oxidation catalyst, and yielding a solution containing
approximately 1.5% by mass of a polystyrenesulfonic acid-doped
poly(3,4-ethylenedioxythiophene) (hereafter referred to as the
complex solution).
[0267] To 100 g of this complex solution were added, under constant
stirring, 1.8 g of 5% by mass ammonia water, followed by 6.0 g of
N-hydroxyethylacrylamide, thus yielding a conductive polymer
solution.
(2) Manufacture of Condenser
[0268] An etched aluminum foil (an anode foil) was connected to an
anode lead terminal, and was then subjected to a chemical
conversion treatment (an oxidation treatment) by applying a voltage
of 100 V within a 10% by mass aqueous solution of ammonium adipate,
thereby forming a dielectric layer on the surface of the aluminum
foil and completing preparation of a condenser intermediate.
[0269] Next, an opposing aluminum cathode foil with a cathode lead
terminal welded thereto was laminated to the anode foil of the
condenser intermediate, with a cellulose separator disposed
therebetween, and the resulting laminate was then wound to form a
condenser element.
[0270] A process in which this condenser element was dipped, under
reduced pressure conditions, in the conductive polymer solution
prepared in (1) above, and subsequently dried for 10 minutes at
120.degree. C. in a hot air dryer, was repeated five times, thereby
forming a solid electrolyte layer on the surface of the dielectric
layer of the condenser intermediate.
[0271] Subsequently, the condenser element with the solid
electrolyte layer formed thereon was packed in an aluminum case and
sealed with a sealing rubber to complete preparation of a
condenser.
[0272] The electrostatic capacitance at 120 Hz and the initial
value of the equivalent series resistance (ESR) at 100 kHz for the
prepared condenser were measured using a LCZ meter 2345
(manufactured by NF Corporation).
[0273] Furthermore, the withstand voltage of the condenser was
measured in the following manner. Namely, a direct current voltage
was applied to the two electrodes and then raised at a rate of 0.2
V/second, and the voltage at the point where the current reached
0.4 A was measured and recorded as the withstand voltage.
[0274] The results of these measurements are shown in Table 1.
TABLE-US-00001 TABLE 1 Electrostatic Withstand pH of conductive
capacitance ESR voltage No. polymer solution (.mu.F) (m.OMEGA.) (V)
Example 1 8.5 47 14 80 2 8.5 47 13 80 3 8.5 45 13 95 4 8.5 47 13 95
5 8.1 47 13 95 6 8.5 47 13 95 Comparative 1 1.8 9 560 35 example 2
8.6 30 430 60 3 8.5 32 75 43
Example 2
[0275] With the exception of adding, to 100 g of the complex
solution of Example 1 under constant stirring, 6.0 g of
N-hydroxyethylacetamide instead of the 6.0 g of
N-hydroxyethylacrylamide, a condenser was prepared in the same
manner as Example 1. The electrostatic capacitance, the ESR, and
the withstand voltage of the condenser were then measured in the
same manner as Example 1. The results of these measurements are
shown in Table 1.
Example 3
[0276] With the exception of adding, to 100 g of the complex
solution of Example 1 under constant stirring, 1.8 g of 5% by mass
ammonia water, followed by 4.5 g of a polyethylene glycol 400
(number average molecular weight: 400) and then 4.5 g of
N-hydroxyethylacrylamide, a conductive polymer solution was
prepared in the same manner as Example 1. Using this conductive
polymer solution, a condenser was prepared in the same manner as
Example 1. The electrostatic capacitance, the ESR, and the
withstand voltage of the condenser were then measured in the same
manner as Example 1. The results of these measurements are shown in
Table 1.
Example 4
[0277] With the exception of adding, to 100 g of the complex
solution of Example 1 under constant stirring, 1.8 g of 5% by mass
ammonia water, followed by 4.5 g of a polyethylene glycol 1000
(number average molecular weight: 1,000) and then 4.5 g of
N-hydroxyethylacrylamide, a conductive polymer solution was
prepared in the same manner as Example 1. Using this conductive
polymer solution, a condenser was prepared in the same manner as
Example 1. The electrostatic capacitance, the ESR, and the
withstand voltage of the condenser were then measured in the same
manner as Example 1. The results of these measurements are shown in
Table 1.
Example 5
[0278] With the exception of adding, to 100 g of the complex
solution of Example 1 under constant stirring, 1.5 g of
1-hydroxyethylimidazole, followed by 4.5 g of the polyethylene
glycol 400 and then 4.5 g of N-hydroxyethylacrylamide, a conductive
polymer solution was prepared in the same manner as Example 1.
Using this conductive polymer solution, a condenser was prepared in
the same manner as Example 1. The electrostatic capacitance, the
ESR, and the withstand voltage of the condenser were then measured
in the same manner as Example 1. The results of these measurements
are shown in Table 1.
Example 6
[0279] With the exception of adding, to 100 g of the complex
solution of Example 1 under constant stirring, 1.8 g of 5% by mass
ammonia water, followed by 4.5 g of the polyethylene glycol 1000
and then 6.0 g of N-hydroxyethylacetamide, a conductive polymer
solution was prepared in the same manner as Example 1. Using this
conductive polymer solution, a condenser was prepared in the same
manner as Example 1. The electrostatic capacitance, the ESR, and
the withstand voltage of the condenser were then measured in the
same manner as Example 1. The results of these measurements are
shown in Table 1.
Comparative Example 1
[0280] With the exception of not adding the amide compound to the
complex solution of Example 1, and simply using the complex
solution, as is, as a conductive polymer solution, a condenser was
prepared in the same manner as Example 1. The electrostatic
capacitance, the ESR, and the withstand voltage of the condenser
were then measured in the same manner as Example 1. The results of
these measurements are shown in Table 1.
Comparative Example 2
[0281] With the exception of adding, to 100 g of the complex
solution of Example 1, 1.8 g of 5% by mass ammonia water, but not
adding an amide compound, a condenser was prepared in the same
manner as Example 1. The electrostatic capacitance, the ESR, and
the withstand voltage of the condenser were then measured in the
same manner as Example 1. The results of these measurements are
shown in Table 1.
Comparative Example 3
[0282] With the exception of adding, to 100 g of the complex
solution of Example 1, 1.8 g of 5% by mass ammonia water, followed
by 2.5 g of trihydroxybenzene, but not adding an amide compound, a
condenser was prepared in the same manner as Example 1. The
electrostatic capacitance, the ESR, and the withstand voltage of
the condenser were then measured in the same manner as Example 1.
The results of these measurements are shown in Table 1.
[0283] All the condensers of Examples 1 to 6 including a solid
electrolyte layer which contained a .pi.-conjugated conductive
polymer, a polyanion and an amide compound exhibited low ESR
values. Further, the electrostatic capacitance was also
satisfactorily maintained in each case. Moreover, the condensers of
Examples 3 to 6, which also included an ion-conductive polymer,
also exhibited a high withstand voltage.
[0284] The condensers of Comparative Examples 1 to 3 including a
solid electrolyte layer which contained a .pi.-conjugated
conductive polymer and a polyanion, but lacked an amide compound
displayed high ESR values.
Example 7
(1) Preparation of Conductive Polymer Solution
[0285] 14.2 g (0.1 mol) of 3,4-ethylenedioxythiophene, and a
solution prepared by dissolving 27.5 g (0.15 mol) of a
polystyrenesulfonic acid in 2,000 ml of ion-exchanged water were
mixed.
[0286] With the obtained mixed solution undergoing constant
stirring at 20.degree. C., a solution containing 29.64 g (0.13 mol)
of ammonium persulfate dissolved in 200 ml of ion-exchanged water,
and 8.0 g (0.02 mol) of a ferric sulfate oxidation catalyst
solution were added gradually, and the resulting mixture was then
stirred and allowed to react for 3 hours.
[0287] The resulting reaction mixture was subjected to a dialysis
treatment, thereby removing the unreacted monomer and oxidant, and
yielding a blue-colored solution containing approximately 1.5% by
mass of a polystyrenesulfonic acid-doped
poly(3,4-ethylenedioxythiophene). This solution was used as a
complex solution.
[0288] 4.00 g of N-methyl-N-vinylacetamide was dispersed uniformly
within 10 g of this complex solution, yielding a conductive polymer
solution (1). This conductive polymer solution (1) was applied to a
glass plate and then dried at 120.degree. C. in a hot air dryer,
thus forming a conductive coating with a thickness of 2 .mu.m. The
electrical conductivity of this conductive coating was measured
using a LORESTA (manufactured by Mitsubishi Chemical Corporation).
The result is shown in Table 2.
TABLE-US-00002 TABLE 2 Comparative Example example 7 8 9 10 11 4
Electrical conductivity 1435 898 809 153 198 3 (S/cm) Electrostatic
1280 1227 1229 1135 1184 1202 capacitance (.mu.F) N-methyl-N- 28 32
37 10 86 0 vinylacetamide content (%) ESR Initial 17 11 12 76 89 55
(m.OMEGA.) 500 hours at 19 12 14 80 92 234 125.degree. C.
(2) Manufacture of Condenser
[0289] An etched aluminum foil (an anode foil) was connected to an
anode lead terminal, and was then subjected to a chemical
conversion treatment (an oxidation treatment) by applying a voltage
of 10 V within a 10% by mass aqueous solution of ammonium adipate,
thereby forming a dielectric layer on the surface of the aluminum
foil and completing preparation of a condenser intermediate.
[0290] Next, an opposing aluminum cathode foil with a cathode lead
terminal welded thereto was laminated to the anode foil of the
condenser intermediate, with a cellulose separator disposed
therebetween, and the resulting laminate was then wound to form a
condenser element.
[0291] This condenser element was dipped in the above conductive
polymer solution (1), and subsequently dried at 120.degree. C. in a
hot air dryer, thereby forming a solid electrolyte layer on the
surface of the dielectric layer of the condenser intermediate.
[0292] Subsequently, the condenser element with the solid
electrolyte layer formed thereon, and an electrolyte solution
composed of a solution containing 20% by mass of ammonium hydrogen
adipate and 80% by mass of ethylene glycol were packed in an
aluminum case and sealed with a sealing rubber, thereby completing
preparation of a condenser.
[0293] The electrostatic capacitance at 120 Hz, the initial value
of the equivalent series resistance (ESR) at 100 kHz, and the ESR
following standing for 500 hours in an atmosphere at 125.degree. C.
were measured for the prepared condenser using a LCZ meter 2345
(manufactured by NF Corporation).
[0294] The results of these measurements are shown in Table 2.
Example 8
[0295] 7.00 g of N-methyl-N-vinylacetamide was dispersed uniformly
within 10 g of the complex solution to form a conductive polymer
solution (2), and with the exception of using this conductive
polymer solution (2), a condenser was prepared in the same manner
as Example 7. This condenser was then evaluated in the same manner
as Example 1. The results of these evaluations are shown in Table
2.
Example 9
[0296] 10.00 g of N-methyl-N-vinylacetamide was dispersed uniformly
within 10 g of the complex solution to form a conductive polymer
solution (3), and with the exception of using this conductive
polymer solution (3), a condenser was prepared in the same manner
as Example 7. This condenser was then evaluated in the same manner
as Example 7. The results of these evaluations are shown in Table
2.
Example 10
[0297] 0.12 g of N-methyl-N-vinylacetamide was dispersed uniformly
within 10 g of the complex solution to form a conductive polymer
solution (4), and with the exception of using this conductive
polymer solution (4), a condenser was prepared in the same manner
as Example 7. This condenser was then evaluated in the same manner
as Example 7. The results of these evaluations are shown in Table
2.
Example 11
[0298] 50.00 g of N-methyl-N-vinylacetamide was dispersed uniformly
within 10 g of the complex solution to form a conductive polymer
solution (5), and with the exception of using this conductive
polymer solution (5), a condenser was prepared in the same manner
as Example 7. This condenser was then evaluated in the same manner
as Example 7. The results of these evaluations are shown in Table
2.
Comparative Example 4
[0299] With the exception of using 10 g of the complex solution, as
is, as a conductive polymer solution, a condenser was prepared in
the same manner as Example 1. This condenser was then evaluated in
the same manner as Example 7. The results of these evaluations are
shown in Table 2.
Example 12
[0300] With the exception of not including the electrolyte solution
when preparing the condenser of Example 7, a condenser was prepared
in the same manner as Example 7. This condenser was then evaluated
in the same manner as Example 7. The results of these evaluations
are shown in Table 3.
TABLE-US-00003 TABLE 3 Comparative Example example 12 13 14 15 16 5
Electrostatic 1075 1055 1096 48 8 44 capacitance (.mu.F)
N-methyl-N- 28 32 37 10 86 0 vinylacetamide content (%) ESR Initial
18 12 13 120 325 1330 (m.OMEGA.) 500 hours at 42 25 26 1410 1530
13552 125.degree. C.
Example 13
[0301] With the exception of using the conductive polymer solution
(2) instead of the conductive polymer solution (1), a condenser was
prepared in the same manner as Example 6. This condenser was then
evaluated in the same manner as Example 7. The results of these
evaluations are shown in Table 3.
Example 14
[0302] With the exception of using the conductive polymer solution
(3) instead of the conductive polymer solution (1), a condenser was
prepared in the same manner as Example 12. This condenser was then
evaluated in the same manner as Example 7. The results of these
evaluations are shown in Table 3.
Example 15
[0303] With the exception of using the conductive polymer solution
(4) instead of the conductive polymer solution (1), a condenser was
prepared in the same manner as Example 12. This condenser was then
evaluated in the same manner as Example 7. The results of these
evaluations are shown in Table 3.
Example 16
[0304] With the exception of using the conductive polymer solution
(5) instead of the conductive polymer solution (1), a condenser was
prepared in the same manner as Example 12. This condenser was then
evaluated in the same manner as Example 7. The results of these
evaluations are shown in Table 3.
Comparative Example 5
[0305] With the exception of using 10 g of the complex solution, as
is, as a conductive polymer solution, a condenser was prepared in
the same manner as Example 12. This condenser was then evaluated in
the same manner as Example 7. The results of these evaluations are
shown in Table 3.
[0306] All the condensers of Examples 7 to 16 including a solid
electrolyte layer which contained a .pi.-conjugated conductive
polymer, a polyanion and a compound containing a vinyl group and an
amide group exhibited low ESR values. Further, even following
heating, increases in the ESR value were able to be suppressed.
Furthermore, in Examples 7 to 16, because the conductive polymer
solution permeated into the dielectric layer, the electrostatic
capacitance was also high.
[0307] The condensers of Comparative Examples 4 and 5 including a
solid electrolyte layer which contained a .pi.-conjugated
conductive polymer and a polyanion, but lacked a compound
containing a vinyl group and an amide group, displayed high ESR
values.
Example 17
(1) Preparation of Conductive Polymer Solution
[0308] 14.2 g (0.1 mol) of 3,4-ethylenedioxythiophene, and a
solution prepared by dissolving 27.5 g (0.15 mol) of a
polystyrenesulfonic acid (molecular weight: approximately 150,000)
in 2,000 ml of ion-exchanged water were mixed at 20.degree. C.
[0309] With the obtained mixed solution undergoing constant
stirring at 20.degree. C., a solution containing 29.64 g (0.13 mol)
of ammonium persulfate dissolved in 200 ml of ion-exchanged water,
and 8.0 g (0.02 mol) of a ferric sulfate oxidation catalyst
solution were added, and the resulting mixture was then stirred and
allowed to react for 3 hours.
[0310] The resulting reaction mixture was subjected to a dialysis
treatment, thereby removing the unreacted monomer, oxidant and
oxidation catalyst, and yielding a solution containing
approximately 1.5% by mass of a polystyrenesulfonic acid-doped
poly(3,4-ethylenedioxythiophene) (hereafter referred to as the
complex solution).
[0311] To 100 g of this complex solution were added, under constant
stirring, 0.36 g of 25% by mass ammonia water, followed by 6.0 g of
polyethylene glycol 200 (number average molecular weight: 200) as a
conductivity improver, and 0.5 g of
3-glycidoxypropyltriethoxysilane as a silane coupling agent, thus
yielding a conductive polymer solution with a pH of 8.5.
(2) Manufacture of Condenser
[0312] An etched aluminum foil (an anode foil) was connected to an
anode lead terminal, and was then subjected to a chemical
conversion treatment (an oxidation treatment) by applying a voltage
of 100 V within a 10% by mass aqueous solution of ammonium adipate,
thereby forming a dielectric layer on the surface of the aluminum
foil and completing preparation of a condenser intermediate.
[0313] Next, an opposing aluminum cathode foil with a cathode lead
terminal welded thereto was laminated to the anode foil of the
condenser intermediate, with a cellulose separator disposed
therebetween, and the resulting laminate was then wound to form a
condenser element.
[0314] A process in which this condenser element was dipped, under
reduced pressure conditions, in the conductive polymer solution
prepared in (1) above, and subsequently dried for 10 minutes at
120.degree. C. in a hot air dryer, was repeated three times,
thereby forming a solid electrolyte layer on the surface of the
dielectric layer of the condenser intermediate.
[0315] Subsequently, the condenser element with the solid
electrolyte layer formed thereon was packed in an aluminum case and
sealed with a sealing rubber to complete preparation of a
condenser.
[0316] The electrostatic capacitance at 120 Hz and the initial
value of the equivalent series resistance (ESR) at 100 kHz for the
prepared condenser were measured using a LCZ meter 2345
(manufactured by NF Corporation).
[0317] Furthermore, the withstand voltage of the condenser was
measured in the following manner. Namely, a direct current voltage
was applied to the two electrodes and then raised at a rate of 0.2
V/second, and the voltage at the point where the current reached
0.4 A was measured and recorded as the withstand voltage.
[0318] The results of these measurements are shown in Table 4.
TABLE-US-00004 TABLE 4 Electrostatic Withstand capacitance ESR
voltage (.mu.F) (m.OMEGA.) (V) Example 17 48 18 95 Example 18 47 20
90 Example 19 47 34 95 Example 20 49 23 80 Example 21 48 30 100
Example 22 48 107 110 Example 23 48 21 105 Example 24 48 18 100
Example 25 48 144 110 Comparative example 6 6 553 43 Comparative
example 7 48 19 80 Comparative example 8 47 20 70 Comparative
example 9 48 24 70 Comparative example 10 48 26 80 Comparative
example 11 48 19 85
Example 18
[0319] With the exception of adding, to 100 g of the complex
solution of Example 17, 5.0 g of dimethylsulfoxide instead of the
6.0 g of polyethylene glycol 200 as the conductivity improver, a
condenser was prepared in the same manner as Example 17. The
electrostatic capacitance, the ESR, and the withstand voltage of
the condenser were then measured in the same manner as Example 17.
The results of these measurements are shown in Table 4.
Example 19
[0320] With the exception of adding, to 100 g of the complex
solution of Example 17, 0.4 g of imidazole and 0.6 g of
3-glycidoxypropyltrimethoxysilane, a condenser was prepared in the
same manner as Example 17. The electrostatic capacitance, the ESR,
and the withstand voltage of the condenser were then measured in
the same manner as Example 17. The results of these measurements
are shown in Table 4.
Example 20
[0321] With the exception of replacing the 0.6 g of
3-glycidoxypropyltrimethoxysilane with 0.6 g of
3-methacryloxypropyltrimethoxysilane, a condenser was prepared in
the same manner as Example 19. The electrostatic capacitance, the
ESR, and the withstand voltage of the condenser were then measured
in the same manner as Example 17. The results of these measurements
are shown in Table 4.
Example 21
[0322] With the exception of adding, to 100 g of the complex
solution of Example 17, 0.4 g of imidazole, 0.6 g of
3-glycidoxypropyltrimethoxysilane and 3.6 g of dimethylsulfoxide, a
condenser was prepared in the same manner as Example 17. The
electrostatic capacitance, the ESR, and the withstand voltage of
the condenser were then measured in the same manner as Example 17.
The results of these measurements are shown in Table 4.
Example 22
[0323] With the exception of replacing the 0.6 g of
3-glycidoxypropyltrimethoxysilane with 0.6 g of
3-methacryloxypropyltrimethoxysilane, a condenser was prepared in
the same manner as Example 21. The electrostatic capacitance, the
ESR, and the withstand voltage of the condenser were then measured
in the same manner as Example 17. The results of these measurements
are shown in Table 4.
Example 23
[0324] With the exception of adding, to 100 g of the complex
solution of Example 17, 0.4 g of imidazole, 0.6 g of
3-glycidoxypropyltrimethoxysilane and 3.6 g of polyethylene glycol
400, a condenser was prepared in the same manner as Example 17. The
electrostatic capacitance, the ESR, and the withstand voltage of
the condenser were then measured in the same manner as Example 17.
The results of these measurements are shown in Table 4.
Example 24
[0325] With the exception of replacing the 0.6 g of
3-glycidoxypropyltrimethoxysilane with 0.6 g of
3-methacryloxypropyltrimethoxysilane, a condenser was prepared in
the same manner as Example 23. The electrostatic capacitance, the
ESR, and the withstand voltage of the condenser were then measured
in the same manner as Example 17. The results of these measurements
are shown in Table 4.
Example 25
[0326] With the exception of replacing the 0.6 g of
3-glycidoxypropyltrimethoxysilane with 0.6 g of
N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, a condenser was
prepared in the same manner as Example 23. The electrostatic
capacitance, the ESR, and the withstand voltage of the condenser
were then measured in the same manner as Example 17. The results of
these measurements are shown in Table 4.
Comparative Example 6
[0327] With the exception of using the complex solution of Example
17, as is, as a conductive polymer solution, a condenser was
prepared in the same manner as Example 17. This condenser was then
evaluated in the same manner as Example 17. The results of these
evaluations are shown in Table 4.
Comparative Example 7
[0328] With the exception of adding, to 100 g of the complex
solution of Example 17, 0.36 g of 25% by mass ammonia water and 6.0
g of polyethylene glycol 200, but not adding the
3-glycidoxypropyltriethoxysilane, a condenser was prepared in the
same manner as Example 17. The electrostatic capacitance, the ESR,
and the withstand voltage of the condenser were then measured in
the same manner as Example 17. The results of these measurements
are shown in Table 4.
Comparative Example 8
[0329] With the exception of adding, to 100 g of the complex
solution of Example 17, 0.36 g of 25% by mass ammonia water and 5.0
g of dimethylsulfoxide, but not adding the
3-glycidoxypropyltriethoxysilane, a condenser was prepared in the
same manner as Example 17. The electrostatic capacitance, the ESR,
and the withstand voltage of the condenser were then measured in
the same manner as Example 17. The results of these measurements
are shown in Table 4.
Comparative Example 9
[0330] With the exception of not adding the 0.6 g of
3-methacryloxypropyltrimethoxysilane, a condenser was prepared in
the same manner as Example 19. The electrostatic capacitance, the
ESR, and the withstand voltage of the condenser were then measured
in the same manner as Example 17. The results of these measurements
are shown in Table 4.
Comparative Example 10
[0331] With the exception of not adding the 0.6 g of
3-glycidoxypropyltrimethoxysilane, a condenser was prepared in the
same manner as Example 21. The electrostatic capacitance, the ESR,
and the withstand voltage of the condenser were measured in the
same manner as Example 17. The results of these measurements are
shown in Table 4.
Comparative Example 11
[0332] With the exception of not adding the 0.6 g of
3-glycidoxypropyltrimethoxysilane, a condenser was prepared in the
same manner as Example 23. The electrostatic capacitance, the ESR,
and the withstand voltage of the condenser were measured in the
same manner as Example 17. The results of these measurements are
shown in Table 4.
[0333] The condensers of Examples 17 to 25 including a solid
electrolyte layer which contained a .pi.-conjugated conductive
polymer, a polyanion, a conductivity improver and a silane coupling
agent, all exhibited high withstand voltage values. Further, the
ESR was of a sufficiently low level to be practically applicable,
and the electrostatic capacitance was also satisfactorily
maintained in each case.
[0334] In contrast, the condensers of Comparative Examples 6 to 11,
which included a solid electrolyte layer that lacked a silane
coupling agent, displayed low withstand voltage values.
Example 26
(1) Preparation of Conductive Polymer Solution
[0335] 14.2 g of 3,4-ethylenedioxythiophene, and a solution
prepared by dissolving 36.7 g of a polystyrenesulfonic acid in
2,000 ml of ion-exchanged water were mixed at 20.degree. C.
[0336] With the obtained mixed solution undergoing constant
stirring at 20.degree. C., a solution containing 29.64 g of
ammonium persulfate dissolved in 200 ml of ion-exchanged water, and
8.0 g of a ferric sulfate oxidation catalyst solution were added
gradually, and the resulting mixture was then stirred and allowed
to react for 3 hours.
[0337] 2,000 ml of ion-exchanged water was added to the thus
obtained reaction solution, and approximately 2,000 ml of the
solution was then removed by ultrafiltration. This operation was
repeated three times.
[0338] To the resulting solution were added 200 ml of 10% by mass
dilute sulfuric acid and 2,000 ml of ion-exchanged water,
approximately 2,000 ml of the solution was removed by
ultrafiltration, 2,000 ml of ion-exchanged water was added, and
approximately 2,000 ml of the solution was removed by
ultrafiltration. This operation was repeated three times.
[0339] Subsequently, 2,000 ml of ion-exchanged water was added to
the thus obtained solution, and approximately 2,000 ml of the
solution was removed by ultrafiltration. This operation was
repeated five times, yielding a polymer solution containing
approximately 1.5% by mass of a blue-colored polystyrenesulfonic
acid-doped poly(3,4-ethylenedioxythiophene) (PSS-PEDOT).
[0340] 2.79 g of imidazole was added to, and dispersed uniformly
within, 100 g of the thus obtained polymer solution, thus yielding
a conductive polymer solution.
(2) Preparation of Low-Thermal Expansion Polymer-Containing
Solution
[0341] To 1 g of an aqueous urethane resin RESAMINE D-6300
(manufactured by Dainichiseika Color & Chemicals Mfg. Co.,
Ltd., 30% by mass, average coefficient of thermal expansion within
a range from 30 to 120.degree. C.: 280 ppm/.degree. C.) was added
299 g of ion-exchanged water, thereby yielding 300 g of a 0.1% by
mass low-thermal expansion polymer solution A.
(3) Manufacture of Condenser
[0342] An etched aluminum foil (an anode foil) was connected to an
anode lead terminal, and was then subjected to a chemical
conversion treatment (an oxidation treatment) in a 10% by mass
aqueous solution of ammonium adipate, thereby forming a dielectric
layer on the surface of the aluminum foil and completing
preparation of a condenser intermediate.
[0343] Next, an opposing aluminum cathode foil with a cathode lead
terminal welded thereto was laminated to the condenser
intermediate, and the resulting laminate was then wound to form a
condenser element. During winding, a separator was sandwiched
between the anode foil and the cathode foil of the condenser
intermediate.
[0344] Following dipping of the condenser element in the
low-thermal expansion polymer solution A prepared in (2) above, the
element was dried at 120.degree. C. in a hot air dryer, thereby
forming an intermediate layer between the dielectric layer of the
anode foil and the cathode foil.
[0345] Subsequently, the condenser element with the formed
intermediate layer was dipped in the conductive polymer solution
prepared in (1) above, and was then dried at 120.degree. C. in a
hot air dryer, thereby forming a solid electrolyte layer on the
surface of the dielectric layer of the condenser intermediate.
[0346] Subsequently, the condenser element with the solid
electrolyte layer formed thereon, and an electrolyte solution
composed of a solution containing 20% by mass of ammonium hydrogen
adipate and 80% by mass of ethylene glycol were packed in an
aluminum case and sealed with a sealing rubber to complete
preparation of a condenser.
Example 27
[0347] A low-thermal expansion polymer solution B was prepared
containing 0.1% by mass of a water-soluble polyester (PLAS COAT
Z-561, manufactured by Goo Chemical Co., Ltd., average coefficient
of thermal expansion within a range from 30 to 120.degree. C.: 65
ppm/.degree. C.).
[0348] With the exception of using this low-thermal expansion
polymer solution B instead of the low-thermal expansion polymer
solution A, a condenser was prepared in the same manner as that
described in Example 26, section (3).
Example 28
[0349] A low-thermal expansion polymer solution C was prepared
containing 0.1% by mass of a solvent-soluble polyimide (a copolymer
of oxydiphthalic anhydride and 2,4-toluenediamine, average
coefficient of thermal expansion within a range from 30 to
120.degree. C.: 25 ppm/.degree. C.).
[0350] With the exception of using this low-thermal expansion
polymer solution C instead of the low-thermal expansion polymer
solution A, a condenser was prepared in the same manner as that
described in Example 26, section (3).
Comparative Example 12
[0351] With the exception of not forming the intermediate layer
during manufacture of the condenser, a condenser was prepared in
the same manner as Example 26.
Comparative Example 13
[0352] With the exceptions of not forming the intermediate layer,
and forming a solid electrolyte layer by dipping the condenser
element in a solution prepared by dissolving 14.2 g of
3,4-ethylenedioxythiophene and 98.5 g of iron (III)
p-toluenesulfonate in 2,000 ml of ion-exchanged water, and
conducting a chemical oxidative polymerization, a condenser was
prepared in the same manner as Example 26.
<Evaluations>
[0353] The withstand voltage, the electrostatic capacitance at 120
Hz, and the value of the equivalent series resistance (ESR) at 100
kHz were measured for each of the prepared condensers. The results
of these measurements are shown in Table 5.
[0354] The withstand voltage was measured in the following manner.
Namely, a direct current voltage was applied to the two electrodes
of the condenser and then raised at a rate of 0.2 V/second, and the
voltage at the point where the current reached 0.4 A was measured
and recorded as the withstand voltage.
[0355] The electrostatic capacitance at 120 Hz and the equivalent
series resistance (ESR) at 100 kHz were measured using a LCZ meter
2345 (manufactured by NF Corporation).
TABLE-US-00005 TABLE 5 Com- parative Example Example Example
Comparative example 26 27 28 example 12 13 Withstand 16 16 15 11 6
voltage (V) Electrostatic 1240 1250 1234 1250 1235 capacitance
(.mu.F) ESR (m.OMEGA.) 18 18 18 15 12
[0356] All the condensers of Examples 26 to 28 that included an
intermediate layer had high withstand voltages, whereas the
condensers of Comparative Examples 12 and 13 that did not include
an intermediate layer had low withstand voltages. Moreover, the
condenser of Comparative Example 13, in which a solid electrolyte
layer had been formed by a chemical oxidative polymerization,
suffered form a low level of productivity.
Example 29
(1) Preparation of Conductive Polymer Solution
[0357] 14.2 g (0.1 mol) of 3,4-ethylenedioxythiophene, and a
solution prepared by dissolving 27.5 g (0.15 mol) of a
polystyrenesulfonic acid (molecular weight: approximately 150,000)
in 2,000 ml of ion-exchanged water were mixed at 20.degree. C.
[0358] With the obtained mixed solution undergoing constant
stirring at 20.degree. C., a solution containing 29.64 g (0.13 mol)
of ammonium persulfate dissolved in 200 ml of ion-exchanged water,
and 8.0 g (0.02 mol) of a ferric sulfate oxidation catalyst
solution were added, and the resulting mixture was then stirred and
allowed to react for 3 hours.
[0359] The resulting reaction mixture was subjected to a dialysis
treatment, thereby removing the unreacted monomer, oxidant and
oxidation catalyst, and yielding a solution containing
approximately 1.5% by mass of a polystyrenesulfonic acid-doped
poly(3,4-ethylenedioxythiophene) (hereafter referred to as the
complex solution).
[0360] 2.5 g of 1-(2-hydroxyethyl)imidazole was dissolved in 100 g
of this complex solution, and 6.0 g of diethylene glycol was then
added, yielding a conductive polymer solution with a pH of 8.3.
[0361] In order to evaluate the performance of the .pi.-conjugated
conductive polymer, the obtained conductive polymer solution was
applied to the surface of a glass sheet and then dried in a hot air
dryer at 120.degree. C., thus forming a conductive coating with a
thickness of 2 .mu.m. The electrical conductivity of this
conductive coating was measured using a LORESTA (manufactured by
Mitsubishi Chemical Corporation). The result is shown in Table
6.
TABLE-US-00006 TABLE 6 pH of Electrical conductive con-
Electrostatic ESR (m.OMEGA.) polymer ductivity capacitance After
solution (S/cm) (.mu.F) Initial 1,000 hours Example 29 8.3 540 47
12 13 Example 30 8.4 435 46 14 15 Example 31 8.2 530 43 15 15
Example 32 7.5 158 45 13 14 Example 33 8.1 346 47 12 13 Example 34
8.6 380 47 12 13 Example 35 8.3 420 47 12 13 Example 36 8.5 530 45
12 13 Example 37 8.3 415 46 13 14 Example 38 8.1 550 47 12 13
Example 39 8.1 380 47 13 14 Example 40 8.1 250 46 12 13 Comparative
2.0 2.0 7 530 1030 example 14 Comparative 8.6 0.5 32 430 670
example 15 Comparative 2.1 620 23 380 720 example 16 Comparative
2.1 530 18 370 750 example 17
(2) Manufacture of Condenser
[0362] An etched aluminum foil (an anode foil) was connected to an
anode lead terminal, and was then subjected to a chemical
conversion treatment (an oxidation treatment) by applying a voltage
of 100 V within a 10% by mass aqueous solution of ammonium adipate,
thereby forming a dielectric layer on the surface of the aluminum
foil and completing preparation of a condenser intermediate.
[0363] Next, an opposing aluminum cathode foil with a cathode lead
terminal welded thereto was laminated to the anode foil of the
condenser intermediate, with a cellulose separator disposed
therebetween, and the resulting laminate was then wound to form a
condenser element.
[0364] A process in which this condenser element was dipped, under
reduced pressure conditions, in the conductive polymer solution
prepared in (1) above, and subsequently dried for 10 minutes at
120.degree. C. in a hot air dryer, was repeated three times,
thereby forming a solid electrolyte layer on the surface of the
dielectric layer of the condenser element.
[0365] Subsequently, the condenser element with the solid
electrolyte layer formed thereon was packed in an aluminum case and
sealed with a sealing rubber to complete preparation of a
condenser.
[0366] The electrostatic capacitance at 120 Hz, the initial value
of the equivalent series resistance (ESR) at 100 kHz, and the ESR
value after standing for 1,000 hours at 105.degree. C. were
measured for the prepared condenser using a LCZ meter 2345
(manufactured by NF Corporation). The results of these measurements
are shown in Table 6.
Example 30
[0367] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 0.36 g of 25% by
mass ammonia water as an alkaline compound, followed by 4.5 g of
thiodiethanol as a conductivity improver, a conductive polymer
solution with a pH of 8.4 was prepared in the same manner as
Example 29. Using the same method as Example 29, a conductive
coating was then formed, and the electrical conductivity of the
conductive coating was measured. Further, a condenser was also
prepared in the same manner as Example 29, and the electrostatic
capacitance at 120 Hz, the initial ESR value at 100 kHz, and the
ESR value after standing for 1,000 hours at 105.degree. C. were
measured for the condenser. The results of these measurements are
shown in Table 6.
Example 31
[0368] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 0.36 g of 25% by
mass ammonia water, followed by 2.5 g of methyl gallate, a
conductive polymer solution with a pH of 8.2 was prepared in the
same manner as Example 29. Using the same method as Example 29, a
conductive coating was then formed, and the electrical conductivity
of the conductive coating was measured. Further, a condenser was
also prepared in the same manner as Example 29, and the
electrostatic capacitance at 120 Hz, the initial ESR value at 100
kHz, and the ESR value after standing for 1,000 hours at
105.degree. C. were measured for the condenser. The results of
these measurements are shown in Table 6.
Example 32
[0369] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 4.5 g of tartaric
acid, and then diethylamine as an alkaline compound, a conductive
polymer solution with a pH of 7.5 was prepared in the same manner
as Example 29. Using the same method as Example 29, a conductive
coating was then formed, and the electrical conductivity of the
conductive coating was measured. Further, a condenser was also
prepared in the same manner as Example 29, and the electrostatic
capacitance at 120 Hz, the initial ESR value at 100 kHz, and the
ESR value after standing for 1,000 hours at 105.degree. C. were
measured for the condenser. The results of these measurements are
shown in Table 6.
Example 33
[0370] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 2.0 g of imidazole
and 3.0 g of diethylene glycol dimethyl ether, a conductive polymer
solution with a pH of 8.1 was prepared in the same manner as
Example 29. Using the same method as Example 29, a conductive
coating was then formed, and the electrical conductivity of the
conductive coating was measured. Further, a condenser was also
prepared in the same manner as Example 29, and the electrostatic
capacitance at 120 Hz, the initial ESR value at 100 kHz, and the
ESR value after standing for 1,000 hours at 105.degree. C. were
measured for the condenser. The results of these measurements are
shown in Table 6.
Example 34
[0371] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 0.36 g of 25% by
mass ammonia water and 3.0 g of tetraethylene glycol dimethyl
ether, a conductive polymer solution with a pH of 8.6 was prepared
in the same manner as Example 29. Using the same method as Example
29, a conductive coating was then formed, and the electrical
conductivity of the conductive coating was measured. Further, a
condenser was also prepared in the same manner as Example 29, and
the electrostatic capacitance at 120 Hz, the initial ESR value at
100 kHz, and the ESR value after standing for 1,000 hours at
105.degree. C. were measured for the condenser. The results of
these measurements are shown in Table 6.
Example 35
[0372] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 2.5 g of
1-(2-hydroxyethylimidazole) and 3.0 g of ethylene glycol diglycidyl
ether, a conductive polymer solution with a pH of 8.3 was prepared
in the same manner as Example 29. Using the same method as Example
29, a conductive coating was then formed, and the electrical
conductivity of the conductive coating was measured. Further, a
condenser was also prepared in the same manner as Example 29, and
the electrostatic capacitance at 120 Hz, the initial ESR value at
100 kHz, and the ESR value after standing for 1,000 hours at
105.degree. C. were measured for the condenser. The results of
these measurements are shown in Table 6.
Example 36
[0373] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 0.36 g of 25% by
mass ammonia water and 6.0 g of acryl glycidyl ether, a conductive
polymer solution with a pH of 8.5 was prepared in the same manner
as Example 29. Using the same method as Example 29, a conductive
coating was then formed, and the electrical conductivity of the
conductive coating was measured. Further, a condenser was also
prepared in the same manner as Example 29, and the electrostatic
capacitance at 120 Hz, the initial ESR value at 100 kHz, and the
ESR value after standing for 1,000 hours at 105.degree. C. were
measured for the condenser. The results of these measurements are
shown in Table 6.
Example 37
[0374] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 2.5 g of
1-(2-hydroxyethylimidazole) and 4.5 g of N,N-dimethylacrylamide, a
conductive polymer solution with a pH of 8.3 was prepared in the
same manner as Example 29. Using the same method as Example 29, a
conductive coating was then formed, and the electrical conductivity
of the conductive coating was measured. Further, a condenser was
also prepared in the same manner as Example 29, and the
electrostatic capacitance at 120 Hz, the initial ESR value at 100
kHz, and the ESR value after standing for 1,000 hours at
105.degree. C. were measured for the condenser. The results of
these measurements are shown in Table 6.
Example 38
[0375] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 0.30 g of 25% by
mass ammonia water and 5 g of maleimide, a conductive polymer
solution with a pH of 8.1 was prepared in the same manner as
Example 29. Using the same method as Example 29, a conductive
coating was then formed, and the electrical conductivity of the
conductive coating was measured. Further, a condenser was also
prepared in the same manner as Example 29, and the electrostatic
capacitance at 120 Hz, the initial ESR value at 100 kHz, and the
ESR value after standing for 1,000 hours at 105.degree. C. were
measured for the condenser. The results of these measurements are
shown in Table 6.
Example 39
[0376] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 0.30 g of 25% by
mass ammonia water, 3.0 g of tetraethylene glycol dimethyl ether
and 5 g of N,N-dimethylacetamide, a conductive polymer solution
with a pH of 8.1 was prepared in the same manner as Example 29.
Using the same method as Example 29, a conductive coating was then
formed, and the electrical conductivity of the conductive coating
was measured. Further, a condenser was also prepared in the same
manner as Example 29, and the electrostatic capacitance at 120 Hz,
the initial ESR value at 100 kHz, and the ESR value after standing
for 1,000 hours at 105.degree. C. were measured for the condenser.
The results of these measurements are shown in Table 6.
Example 40
[0377] With the exception of adding, to 100 g of the complex
solution obtained in section (1) of Example 29, 2.5 g of
vinylimidazole, 5.0 g of N-vinylpyrrolidone and 4.0 g of acryl
glycidyl ether, a conductive polymer solution with a pH of 8.1 was
prepared in the same manner as Example 29. Using the same method as
Example 29, a conductive coating was then formed, and the
electrical conductivity of the conductive coating was measured.
Further, a condenser was also prepared in the same manner as
Example 29, and the electrostatic capacitance at 120 Hz, the
initial ESR value at 100 kHz, and the ESR value after standing for
1,000 hours at 105.degree. C. were measured for the condenser. The
results of these measurements are shown in Table 6.
Comparative Example 14
[0378] With the exception of not adding the diethylene glycol to
the complex solution obtained in section (1) of Example 29, a
conductive polymer solution with a pH of 2.0 was prepared in the
same manner as Example 29. Using the same method as Example 29, a
conductive coating was then formed, and the electrical conductivity
of the conductive coating was measured. Further, a condenser was
also prepared in the same manner as Example 29, and the
electrostatic capacitance at 120 Hz, the initial ESR value at 100
kHz, and the ESR value after standing for 1,000 hours at
105.degree. C. were measured for the condenser. The results of
these measurements are shown in Table 6.
Comparative Example 15
[0379] To 100 g of the complex solution obtained in section (1) of
Example 29 was added 0.36 g of 25% by mass ammonia water, yielding
a conductive polymer solution with a pH of 8.6. Using the same
method as Example 29, a conductive coating was then formed, and the
electrical conductivity of the conductive coating was measured.
Further, a condenser was also prepared in the same manner as
Example 29, and the electrostatic capacitance at 120 Hz, the
initial ESR value at 100 kHz, and the ESR value after standing for
1,000 hours at 105.degree. C. were measured for the condenser. The
results of these measurements are shown in Table 6.
Comparative Example 16
[0380] To 100 g of the complex solution obtained in section (1) of
Example 29 was added 6.0 g of ethylene glycol, yielding a
conductive polymer solution with a pH of 2.1. Using the same method
as Example 29, a conductive coating was then formed, and the
electrical conductivity of the conductive coating was measured.
Further, a condenser was also prepared in the same manner as
Example 29, and the electrostatic capacitance at 120 Hz, the
initial ESR value at 100 kHz, and the ESR value after standing for
1,000 hours at 105.degree. C. were measured for the condenser. The
results of these measurements are shown in Table 6.
Comparative Example 17
[0381] To 100 g of the complex solution obtained in section (1) of
Example 29 was added 7.5 g of N-methylpyrrolidone, yielding a
conductive polymer solution with a pH of 2.1. Using the same method
as Example 29, a conductive coating was then formed, and the
electrical conductivity of the conductive coating was measured.
Further, a condenser was also prepared in the same manner as
Example 29, and the electrostatic capacitance at 120 Hz, the
initial ESR value at 100 kHz, and the ESR value after standing for
1,000 hours at 105.degree. C. were measured for the condenser. The
results of these measurements are shown in Table 6.
[0382] All the conductive coatings of Examples 29 to 40, which were
formed by applying a conductive polymer solution containing a
.pi.-conjugated conductive polymer, a polyanion, a conductivity
improver, an alkaline compound and a solvent, exhibited high
electrical conductivity values. Further, each the condenser
prepared by using the conductive coatings of Examples 29 to 40 as
solid electrolyte layers exhibited a high electrostatic capacitance
and a low ESR value.
[0383] The conductive coating of Comparative Example 15 that
contained no conductivity improver had a low electrical
conductivity. Further, the condenser prepared using the conductive
coating of Comparative Example 15 as the solid electrolyte layer
had a high ESR value.
[0384] Furthermore, in the case of the conductive coatings of
Comparative Examples 16 and 17, which contained no alkaline
compound, although the electrical conductivity was high, the
electrostatic capacitance was low and the ESR was high.
* * * * *