U.S. patent application number 14/081558 was filed with the patent office on 2014-06-26 for modified perovskite type composite oxide, method for preparing the same, and composite dielectric material.
This patent application is currently assigned to Nippon Chemical Industrial Co., Ltd.. The applicant listed for this patent is Nippon Chemical Industrial Co., Ltd.. Invention is credited to Shinji Tanabe.
Application Number | 20140179826 14/081558 |
Document ID | / |
Family ID | 41550440 |
Filed Date | 2014-06-26 |
United States Patent
Application |
20140179826 |
Kind Code |
A1 |
Tanabe; Shinji |
June 26, 2014 |
MODIFIED PEROVSKITE TYPE COMPOSITE OXIDE, METHOD FOR PREPARING THE
SAME, AND COMPOSITE DIELECTRIC MATERIAL
Abstract
The invention provides a modified perovskite type composite
oxide in which the particle surface of a perovskite type composite
oxide is coated with a first component of at least one selected
from TiO.sub.2 and SiO.sub.2 and a second component of at least one
selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm,
wherein the coating is formed by hydrolyzing at least one selected
from a hydrolyzable TiO.sub.2 precursor and a hydrolyzable
SiO.sub.2 precursor as a source of the first component and a salt
of at least one selected from a group consisting of Al, Zr, Nd, La,
Ce, Pr, and Sm as a source of the second component, and then
calcining them.
Inventors: |
Tanabe; Shinji; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Nippon Chemical Industrial Co., Ltd. |
Tokyo |
|
JP |
|
|
Assignee: |
Nippon Chemical Industrial Co.,
Ltd.
Tokyo
JP
|
Family ID: |
41550440 |
Appl. No.: |
14/081558 |
Filed: |
November 15, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12737473 |
Apr 19, 2011 |
8609748 |
|
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PCT/JP2009/062860 |
Jul 16, 2009 |
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14081558 |
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Current U.S.
Class: |
523/216 ;
428/219; 501/134; 501/139; 501/152; 501/153; 523/200 |
Current CPC
Class: |
C04B 35/62813 20130101;
C01B 33/126 20130101; C04B 2235/3236 20130101; C04B 2235/768
20130101; H01B 3/12 20130101; Y10T 428/2991 20150115; C01B 33/12
20130101; C04B 35/62821 20130101; C04B 35/10 20130101; C01G 23/053
20130101; C08K 3/10 20130101; C04B 2235/449 20130101; C08K 3/34
20130101; C04B 2235/5409 20130101; C04B 35/62815 20130101; C04B
35/62807 20130101; C04B 35/50 20130101; C04B 35/4682 20130101; C01P
2004/84 20130101; C04B 2235/3248 20130101; C04B 35/62655 20130101;
Y10T 428/2993 20150115; C08K 3/22 20130101 |
Class at
Publication: |
523/216 ;
501/134; 501/139; 501/152; 501/153; 523/200; 428/219 |
International
Class: |
C04B 35/50 20060101
C04B035/50; C08K 3/10 20060101 C08K003/10; C08K 3/22 20060101
C08K003/22; C08K 3/34 20060101 C08K003/34; C04B 35/468 20060101
C04B035/468; C04B 35/10 20060101 C04B035/10 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 18, 2008 |
JP |
2008-187270 |
Jul 18, 2008 |
JP |
2008-187646 |
Claims
1. A modified perovskite type composite oxide in which a particle
surface of a perovskite type composite oxide is coated with a first
component of at least one selected from TiO.sub.2 and SiO.sub.2,
and a second component of at least one selected from a group
consisting of Al, Zr, Nd, La, Ce, Pr, and Sm, wherein a coating is
formed by hydrolyzing at least one selected from a hydrolyzable
TiO.sub.2 precursor and a hydrolyzable SiO.sub.2 precursor as a
source of the first component and a salt of at least one selected
from a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm as a
source of the second component, and then calcining them.
2. The modified perovskite type composite oxide as set forth in
claim 1, wherein the first component is TiO.sub.2 and the second
component is at least one selected from a group consisting of Nd,
La, Ce, Pr, and Sm.
3. The modified perovskite type composite oxide as set forth in
claim 1, wherein the first component is SiO.sub.2 and the second
component is at least one selected from a group consisting of Al,
Zr, Nd, La, Ce, Pr, and Sm.
4. The modified perovskite type composite oxide as set forth in
claim 1, wherein the coating is at a ratio of 0.05% by mass to 20%
by mass in terms of oxides with respect to the perovskite type
composite oxide.
5. The modified perovskite type composite oxide as set forth in
claim 1, wherein the perovskite type composite oxide is of an
ABO.sub.3 type, an A-site element is at least one selected from a
group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at
least one selected from Ti and Zr.
6. The modified perovskite type composite oxide as set forth in
claim 1, wherein a BET specific surface area of the perovskite type
composite oxide is 0.5 m.sup.2/g to 12 m.sup.2/g.
7. A method for preparing the modified perovskite type composite
oxide, comprising: (A1) a step of dispersing perovskite type
composite oxide particles in a solvent to prepare a slurry; (A2) a
step of adding a source of a first component of at least one
selected from a hydrolyzable TiO.sub.2 precursor and a hydrolyzable
SiO.sub.2 precursor and a salt of a source of a second component of
at least one selected from a group consisting of Al, Zr, Nd, La,
Ce, Pr, and Sm to the slurry obtained in (A1), carrying out a
hydrolysis reaction of the precursor(s) and the salt in the
presence of a catalyst, and then drying the slurry; and (A3) a step
of calcining the dried product obtained in (A2).
8. The method for preparing the modified perovskite type composite
oxide as set forth in claim 7, wherein the solvent is a hydrophilic
organic solvent and the catalyst is an organic alkali.
9. A composite dielectric material comprising the modified
perovskite type composite oxide as set forth in claim 1 and a
polymer material.
10. The modified perovskite type composite oxide as set forth in
claim 2, wherein the coating is at a ratio of 0.05% by mass to 20%
by mass in terms of oxides with respect to the perovskite type
composite oxide.
11. The modified perovskite type composite oxide as set forth in
claim 3, wherein the coating is at a ratio of 0.05% by mass to 20%
by mass in terms of oxides with respect to the perovskite type
composite oxide.
12. The modified perovskite type composite oxide as set forth in
claim 2, wherein the perovskite type composite oxide is of an
ABO.sub.3 type, an A-site element is at least one selected from a
group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at
least one selected from Ti and Zr.
13. The modified perovskite type composite oxide as set forth in
claim 3, wherein the perovskite type composite oxide is of an
ABO.sub.3 type, an A-site element is at least one selected from a
group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at
least one selected from Ti and Zr.
14. The modified perovskite type composite oxide as set forth in
claim 4, wherein the perovskite type composite oxide is of an
ABO.sub.3 type, an A-site element is at least one selected from a
group consisting of Ba, Ca, Sr, and Mg, and a B-site element is at
least one selected from Ti and Zr.
15. The modified perovskite type composite oxide as set forth in
claim 2, wherein a BET specific surface area of the perovskite type
composite oxide is 0.5 m.sup.2/g to 12 m.sup.2/g.
16. The modified perovskite type composite oxide as set forth in
claim 3, wherein a BET specific surface area of the perovskite type
composite oxide is 0.5 m.sup.2/g to 12 m.sup.2/g.
17. The modified perovskite type composite oxide as set forth in
claim 4, wherein a BET specific surface area of the perovskite type
composite oxide is 0.5 m.sup.2/g to 12 m.sup.2/g.
18. A composite dielectric material comprising the modified
perovskite type composite oxide as set forth in claim 2 and a
polymer material.
19. A composite dielectric material comprising the modified
perovskite type composite oxide as set forth in claim 3 and a
polymer material.
20. A composite dielectric material comprising the modified
perovskite type composite oxide as set forth in claim 4 and a
polymer material.
Description
TECHNICAL FIELD
[0001] The present invention relates to a modified perovskite type
composite oxide, a method for preparing the same, and a composite
dielectric material using the modified perovs kite type composite
oxide.
BACKGROUND ART
[0002] In order to produce small-sized, thin, and high-density
electronic instruments, a multilayer printed wiring board has been
frequently used. By providing a layer including high-dielectric
constant materials on the inner layer or surface layer of such a
multilayer printed wiring board to improve the package density, it
becomes possible to cope with demand for production of
smaller-sized, thinner, and higher-density electronic
instruments.
[0003] Conventionally, a ceramic sintered body obtained by molding
ceramic powders and then sintering the resultant has been used as a
high-dielectric constant material. Thus, the size and shape of the
material has been restricted by a molding method. In addition,
since a sintered body is very hard and fragile, it has been
difficult to process the sintered body freely, and thus it has been
extremely difficult to obtain any given shape or a complicated
shape.
[0004] In this regard, a composite dielectric material formed by
dispersing an inorganic filler with a high dielectric constant in a
resin has drawn attention due to its high processability. For
example, a perovskite type composite oxide is known as such an
inorganic filler with a high dielectric constant used herein (see,
for example, Patent Citation 1). However, the perovskite type
composite oxide has a problem in that the specific surface area
changes over time and the dielectric characteristics are
deteriorated. In addition, it has another problem in that when it
is brought into contact with water, A-site metals such as Ba, Ca,
Sr, and Mg in the structure are eluted, and thus, peeling of the
interface between the resin and the inorganic filler or
deterioration in insulation due to ion migration occurs.
[0005] Meanwhile, as described in Patent Citations 2 to 6, it is
known that an inorganic filler with a high dielectric constant,
such as barium titanate, is surface-treated with a coupling agent
for the purpose of improving dispersibility in a resin. [0006]
Patent Citation 1: Pamphlet of International Publication WO
2005/093763 [0007] Patent Citation 2: Japanese Patent Laid-Open No.
2003-49092 [0008] Patent Citation 3: Japanese, Patent Laid-Open No.
2004-253219 [0009] Patent Citation 4: Japanese Patent Laid-Open No.
2005-2281 [0010] Patent Citation 5: Japanese Patent Laid-Open No.
2005-8665 [0011] Patent Citation 6: Japanese Patent Laid-Open No.
2005-15652
DISCLOSURE OF INVENTION
Technical Problem
[0012] However, the present inventors have investigated with regard
to this, and as a result, they have found that even though the
particle surface of a perovskite type composite oxide is simply
treated with a coupling agent, the change in the specific surface
areas over time or the elution of A-site metals such as Ba cannot
be reduced sufficiently, and moreover, even when the perovskite
type composite oxide particle after treatment is subjected to a
general cracking treatment, a significant deviation from the
particle size distribution prior to treatment is caused. If the
particle size distribution changes significantly, a problem occurs
in that a property of being evenly filled with resin and/or an
affinity with resin is lowered. Also, another problem occurs in
that even when it is attempted to keep the particle size
distribution of the treated particle close to the particle size
distribution prior to treatment, a noticeably long time is taken
for cracking or an untreated surface is exposed through the
destruction of the particles. In addition, yet another problem
occurs in that coated components are eluted from the coated
components modifying the perovskite type composite oxide.
[0013] Accordingly, the present invention has been made to solve
the above-described problems, and thus it has the objectives to
provide a modified perovskite type composite oxide in which the
dielectric characteristics are equal to or better than those prior
to modification, there is no substantial elution of coating
components from the coating components modifying the perovskite
type composite oxide, and change in the specific surface areas over
time and elution of the A-site metals of the perovskite type
composite oxide are suppressed effectively, while the cracking
traits are good, a method for preparing the same, and a composite
dielectric material using the modified perovskite type composite
oxide.
Technical Solution
[0014] Therefore, the present inventors have made extensive
investigations in order to solve the above-described problems, and
as a result, they have found that a modified perovskite type
composite oxide in which the particle surface of a perovskite type
composite oxide is coated with a coating layer that is produced by
hydrolyzing a hydrolyzable TiO.sub.2 precursor and/or a
hydrolyzable SiO.sub.2 precursor, and a salt of a specific metal
element, and then calcining them, solves the above-described
problems, thereby completing the present invention.
[0015] That is, the present invention is directed to a modified
perovskite type composite oxide in which the particle surface of a
perovskite type composite oxide is coated with a first component of
at least one selected from TiO.sub.2 and SiO.sub.2 and a second
component of at least one selected from a group consisting of Al,
Zr, Nd, La, Ce, Pr, and Sm, wherein the coating is formed by
hydrolyzing at least one selected from a hydrolyzable TiO.sub.2
precursor and a hydrolyzable SiO.sub.2 precursor as a source of the
first component and a salt of at least one selected from a group
consisting of Al, Zr, Nd, La, Ce, Pr, and Sm as a source of the
second component, and then calcining them.
[0016] It is preferable that the first component be TiO.sub.2 and
the second component be at least one selected from a group
consisting of Nd, La, Ce, Pr, and Sm.
[0017] It is preferable that the first component be SiO.sub.2 and
the second component be at least one selected from a group
consisting of Al, Zr, Nd, La, Ce, Pr, and Sm.
[0018] It is preferable that the coating be in a ratio from 0.05%
by mass to 20% by mass in terms of oxides with respect to the
perovskite type composite oxide.
[0019] It is preferable that the perovskite type composite oxide to
be coated be of an ABO.sub.3 type and the A-site element is at
least one selected from a group consisting of Ba, Ca, Sr and Mg and
the B-site element be at least one selected from a group consisting
of Ti and Zr.
[0020] It is preferable that the BET specific surface area of the
perovskite type composite oxide to be coated be 0.5 m.sup.2/g to 12
m.sup.2/g.
[0021] Furthermore, the present invention is directed to a method
for preparing the modified perovskite type composite oxide,
including (A1) a step of dispersing perovskite type composite oxide
particles in a solvent to prepare a slurry, (A2) a step of adding a
source of a first component of at least one selected from a
hydrolyzable TiO.sub.2 precursor and a hydrolyzable SiO.sub.2
precursor and a salt of a source of a second component of at least
one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and
Sm to the slurry obtained in (A1), carrying out a hydrolysis
reaction of the precursor(s) and the salt in the presence of a
catalyst, and then drying the slurry, and (A3) a step of calcining
the dried product obtained in (A2).
[0022] It is preferable that the solvent be a hydrophilic organic
solvent and the catalyst be an organic alkali.
[0023] Moreover, the present invention is directed to a composite
dielectric material, which includes the above-described modified
perovskite type composite oxide and a polymer material.
BEST MODE FOR CARRYING OUT THE INVENTION
[0024] Hereinbelow, the present invention will be described in
detail with reference to its preferred embodiments.
(Modified Perovskite Type Composite Oxide)
[0025] The modified perovskite type composite oxide of the present
invention is a modified perovskite type composite oxide in which
the particle surface is coated with a first component of at least
one selected from TiO.sub.2 and SiO.sub.2 and a second component of
at least one selected from a group consisting of Al, Zr, Nd, La,
Ce, Pr, and Sm, wherein the coating is formed by hydrolyzing at
least one selected from a hydrolyzable TiO.sub.2 precursor and a
hydrolyzable SiO.sub.2 precursor as a source of the first component
and a salt of at least one selected from a group consisting of Al,
Zr, Nd, La, Ce, Pr, and Sm as a source of the second component, and
then calcining them.
[0026] In the modified perovskite type composite oxide of the
present invention, a modified perovskite type composite oxide in
which the first component is TiO.sub.2 and the second component is
at least one selected from a group consisting of Nd, La, Ce, Pr,
and Sm, or a modified perovskite type composite oxide in which the
first component is SiO.sub.2 and the second component is at least
one selected from a group consisting of Al, Zr, Nd, La, Ce, Pr, and
Sm is preferred, from the viewpoint that there is no substantial
elution of coating components from the modifying coating
components, the effects of suppressing change in specific surface
areas over time and the elution of the A-site metals of the
perovskite type composite oxide effectively are particularly high,
and the cracking traits are good.
[0027] The perovskite type composite oxide to be modified is not
particularly limited, but it is preferably a perovskite type
composite oxide in which at least one metal element selected from
the group consisting of Ca, Ba, Sr, and Mg is disposed in an A-site
and at least one metal element selected from the group consisting
of Ti and Zr is disposed in a B-site in an ABO.sub.3-type
perovskite. Specific examples of the preferable compound include
BaTiO.sub.3, CaTiO.sub.3, SrTiO.sub.3, MgTiO.sub.3,
Ba.sub.xCa.sub.1-xTiO.sub.3 (wherein x satisfies 0<x<1),
BaxSr.sub.1-xZrO.sub.3 (wherein x satisfies 0<x<1),
BaTi.sub.xZr.sub.1-xO.sub.3 (wherein x satisfies 0<x<1), and
Ba, Ca.sub.1-xTi.sub.yZr.sub.1-yO.sub.3 (wherein x satisfies
0<x<1 and y satisfies 0<y<1). These perovskite type
composite oxides may be used singly or in combination of two or
more kinds thereof.
[0028] The preparation history of such a perovskite type composite
oxide is not particularly limited, and for example, the perovskite
type composite oxides obtained by ordinary methods such as a
co-precipitation method, a hydrolysis method, a wet method such as
a hydrothermal synthesis method, a sol-gel method, and a
solid-phase method are used. The physical properties of such
perovskite type composite oxides are not particularly limited, but
the perovskite type composite oxides preferably have a BET specific
surface area of 0.5 m.sup.2/g to 12 m.sup.2/g, and more preferably
1.5 m.sup.2/g to 6 m.sup.2/g in terms of handling ability,
dispersibility, and adhesion with a resin. Further, the perovskite
type composite oxides having an average particle diameter of 0.1
.mu.m to 2 .mu.m, and preferably 0.2 .mu.m to 1 .mu.m are
preferable because they further improve handling ability and
dispersibility. This average particle diameter is determined by a
laser light scattering method. In addition, in order to obtain a
product with a high purity, perovskite type composite oxides with a
low content of impurities content are particularly preferable.
[0029] Furthermore, the perovskite type composite oxide to be
modified may contain accessory component elements. Examples of the
accessory component elements include metal elements, metalloid
elements, transition metal elements, and rare earth elements,
having an atomic number of 3 or more, other than elements in the
A-site and the B-site that constitute a perovskite type composite
oxide. Among these, at least one selected from Sc, Y, La, Ce, Pr,
Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, V, Bi, Al, W, Mo,
Nb, and Si is preferable. Further, the content of such accessory
component elements is 0.05% by mole to 20% by mole, and more
preferably 0.5% by mole to 5% by mole, with respect to the
perovskite type composite oxide.
[0030] Moreover, the particle shape of the perovskite type
composite oxide is not particularly limited, but it may be any one
of a spherical shape, a granular shape, a planar shape, a scale
shape, a whisker shape, a rod shape, a filamentous shape, and the
like.
[0031] In the modified perovskite type composite oxide of the
present invention, the coating including a first component of at
least one selected from TiO.sub.2 and SiO.sub.2 and a second
component of at least one selected from a group consisting of Al,
Zr, Nd, La, Ce, Pr, and Sm is characterized in that it is formed by
hydrolyzing at least one selected from a hydrolyzable TiO.sub.2
precursor and a hydrolyzable SiO.sub.2 precursor as a source of the
first component and a salt of at least one selected from a group
consisting of Al, Zr, Nd, La, Ce, Pr, and Sm as a source of the
second component, and then calcining the hydrolyzed product.
Usually, the untreated perovskite type composite oxide has a basic
pH of the particle surface, but a surface potential that cannot be
obtained originally from barium titanate-based oxides can be formed
since the above-described coating can adjust the pH of the
particles surface to a neutral or around basic pH (pH 7 to 9, and
preferably 7 to 8). Accordingly, its application availability
becomes wide to other applications such as an application
exclusively for ceramic capacitors, as well as inorganic fillers,
external additives for toners, or the like. Further, the pH value
of the particle surface is determined by adding 100 g of pure water
to 4 g of the modified perovskite type composite oxide, stirring
the mixture at 25.degree. C. for 60 hours, and then measuring the
pH of the supernatant by a pH meter.
[0032] Examples of the hydrolyzable TiO.sub.2 precursor include
titanium alkoxides such as tetramethoxytitanium,
tetraethoxytitanium, tetrapropoxytitanium, tetraisopropoxytitanium,
and tetra-n-butoxytitanium, and titanate-based coupling agents such
as isopropyltriisostearoyl titanate,
isopropyltridodecylbenzenesulfonyl titanate,
isopropyltris(dioctylpyrophosphate)titanate,
tetraoctylbis(ditridecylphosphite)titanate,
tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite
titanate, bis(dioctylpyrophosphate)oxyacetate titanate,
bis(dioctylpyrophosphate)ethylene titanate, isopropyltrioctanoyl
titanate, isopropyldimethacrylisostearoyl titanate,
isopropylisostearoyldiacryl titanate,
isopropyltri(dioctylphosphate)titanate, isopropyltricumylphenyl
titanate, isopropyltri(N-aminoethyl-aminoethyl) titanate,
dicumylphenyloxyacetate titanate, diisostearoylethylene titanate,
polydiisopropyl titanate, tetranormalbutyl titanate, and
polydinormalbutyl titanate. These hydrolyzable TiO.sub.2 precursors
may be used singly or in combination of two or more kinds
thereof.
[0033] Examples of the hydrolyzable SiO.sub.2 precursor include
silane alkoxides such as tetramethoxysilane, tetraethoxysilane,
tetra-n-propoxysilane, tetraisopropoxysilane, and
tetra-n-butoxysilane, for example, silane coupling agents such as
.gamma.-(2-aminoethyl)aminopropyltrimethoxysilane,
.gamma.-(2-aminoethyl)aminopropylmethyldimethoxysilane,
aminosilane, .gamma.-aminopropyltriethoxysilane,
N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,
N-.beta.-(N-vinylbenzylaminoethyl)-.gamma.-aminopropyltrimethoxysilane,
hexamethyldisilazane, trimethylsilane, trimethylchlorsilane,
dimethyldichlorsilane, methyltrichlorsilane,
aryldimethylchlorsilane, benzyldimethylchlorsilane,
methyltrimethoxysilane, methyltriethoxysilane,
isobutyltrimethoxysilane, dimethyldimethoxysilane,
dimethyldiethoxysilane, trimethylmethoxysilane,
hydroxypropyltrimethoxysilane, phenyltrimethoxysilane,
n-butyltrimethoxysilane, n-hexadecyltrimethoxysilane,
n-octadecyltrimethoxysilane, vinyltrimethoxysilane,
vinyltriethoxysilane, .gamma.-methacryloxypropyltrimethoxysilane,
vinyltriacetoxysilane, .gamma.-chloropropyltrimethoxysilane,
.beta.-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,
.gamma.-glycidoxypropyltrimethoxysilane,
.gamma.-mercaptopropyltrimethoxysilane,
N-.beta.-(aminoethyl)-.gamma.-aminopropyltrimethoxysilane,
.gamma.-ureidopropyltriethoxysilane, and aminofluorinesilane. These
hydrolyzable SiO.sub.2 precursors may be used singly or in
combination of two or more kinds thereof.
[0034] Examples of the salt of Al include aluminum alkoxides such
as trimethoxyaluminum, triethoxyaluminum, tripropoxyaluminum,
triisopropoxyaluminum, tri-n-butoxyaluminum,
tri-sec-butoxyaluminum, tri-tert-butoxyaluminum, aluminate-based
coupling agents such as ethyl acetoacetate aluminum diisopropylate,
methyl acetoacetate aluminum diisopropylate, ethyl acetate aluminum
dibutylate, alkyl acetoacetate aluminum diisopropylate, and
aluminum monoacetyl acetate bis(ethylacetoacetate), aluminum
acetate, and aluminum nitrate nonahydrate. These salts of Al may be
used singly or in combination of two or more kinds thereof.
[0035] Examples of the salt of Zr include zirconium alkoxides such
as tetraethoxyzirconium, tetramethoxyzirconium,
tetraisopropoxyzirconium, tetra-n-butoxyzirconium, and
tetra-tert-butoxyzirconium, zirconium alkoxides such as
ethoxyzirconum steareate, zirconium chelate compounds such as
zirconiumtetraacetyl acetonate, and zirconium
.alpha.-hydroxycarboxylate, and zirconate-based coupling agents
such as zirconium soaps and zirconium acetate. These salts of Zr
may be used singly or in combination of two or more kinds
thereof.
[0036] Examples of the salt of Nd, La, Ce, Pr, and Sm include
acetates, nitrates, chlorides, and alkoxides, and more
specifically, neodymium acetate monohydrate, neodymium nitrate
hexahydrate, neodymium chloride hexahydrate,
triisopropoxyneodymium, lanthanum acetate 1.5-hydrate, lanthanum
nitrate hexahydrate, triisopropoxylantane, lanthanum chloride
heptahydrate, cerium acetate monohydrate, cerium nitrate
hexahydrate, cerium chloride heptahydrate, praseodymium acetate
dihydrate, praseodymium nitrate hexahydrate, praseodymium chloride
heptahydrate, triisopropoxypraseodymium, samarium acetate
tetrahydrate, samarium nitrate hexahydrate, samarium chloride
hexahydrate, and triisopropoxysamarium. These salts may be used
singly or in combination of two or more kinds thereof.
[0037] The calcining temperature during formation of the coating
layer is preferably 400.degree. C. or higher, and more preferably
600.degree. C. to 1200.degree. C. If the calcining temperature is
too low, organic matter remains in the coating component, and
further, the coating is not sufficiently densified. Thus, the
effect of reduction in elution of the A-site metals is low, and
there may be cases where the A-site metal-eluted amount becomes
larger than that prior to coating, or the relative dielectric
constant is reduced. On the other hand, if the calcining
temperature is too high, fusion between the particles or particle
growth becomes significant, and even though the cracking treatment
is carried out, the shape or the particle size distribution tends
to deviate considerably from that prior to modification, and
therefore, the calcining temperature is preferably 1200.degree. C.
or lower. Further, the calcining time is preferably 2 hours or
longer, and more preferably 3 hours to 10 hours.
[0038] The ratio of the coating is preferably 0.05% by mass to 20%
by mass, and more preferably 0.1% by mass to 5% by mass, in terms
of oxides with respect to the perovskite type composite oxide. If
the ratio of the coating is less than 0.05% by mass, there may be
cases where the effects of suppressing change in the specific
surface areas over time and reducing the elution cannot be obtained
sufficiently, whereas if the ratio of the coating is more than 20%
by mass, there may be cases where the dielectric characteristics of
the modified perovskite type composite oxide are reduced. Further,
from the viewpoint that stoichiometric homogeneity is kept with
respect to the first component, the amount of the second component
element contained in the coating is preferably 0.04% by mass to 95%
by mass, and more preferably 0.03% by mass to 80% by mass, in terms
of oxides. Particularly, when the first component is TiO.sub.2, the
amount of the second component is preferably 0.04% by mass to 15%
by mass, and more preferably 0.08% by mass to 3% by mass, in terms
of oxides, in the coating, and when the first component is
SiO.sub.2, the second component is preferably 5% by mass to 95% by
mass, and more preferably 20% by mass to 80% by mass, in terms of
oxides, in the coating, which is particularly desirable from the
viewpoint that elution of the A-site metals can be suppressed more
efficiently.
<Method for Preparing Modified Perovskite Type Composite
Oxide>
[0039] The modified perovskite type composite oxide of the present
invention can be prepared by a method including the following
steps:
[0040] (A1) a step of dispersing the perovskite type composite
oxide particles in a solvent to prepare a slurry,
[0041] (A2) a step of adding a source of a first component of at
least one selected from a hydrolyzable TiO.sub.2 precursor and a
hydrolyzable SiO.sub.2 precursor and a salt of a source of a second
component of at least one selected from a group consisting of Al,
Zr, Nd, La, Ce, Pr, and Sm to the slurry obtained in (A1), carrying
out a hydrolysis reaction of the precursor(s) and the salt in the
presence of a catalyst, and then drying the slurry, and
[0042] (A3) a step of calcining the dried product obtained in the
(A2).
[0043] In step (A1), preferably 100 parts by mass to 900 parts by
mass, and more preferably 150 parts by mass to 400 parts by mass of
the solvent is added to 100 parts by mass of the perovskite type
composite oxide to be modified, followed by stirring, thereby
preparing a slurry in which each of the particles of the perovskite
type composite oxide are uniformly dispersed.
[0044] As the solvent, water, a hydrophilic organic solvent, or a
mixture thereof can be used, but it is preferable to use a
hydrophilic organic solvent from the viewpoint that an A-site metal
such as Ba, Ca, Sr, and Mg may be eluted from the perovskite type
composite oxide by contact with water, or that the cracking traits
of the obtained modified perovskite type composite oxide is further
improved.
[0045] Examples of the hydrophilic organic solvent include glycols
and alcohols. Specific examples of the glycol include propylene
glycol monoethyl ether, propylene glycol monomethyl ether,
dipropylene glycol monomethyl ether, diethylene
glycolmonobutylether, ethylene glycol, propylene glycol, and
diethylene glycol. Further, specific examples of the alcohol
include methanol, ethanol, isopropyl alcohol, n-butanol, and
pentanol. These solvents may be used singly or in combination of
two or more kinds thereof. Among these solvents, propylene glycol
monoethyl ether, dipropylene glycol monomethyl ether, diethylene
glycolmonobutylether, methanol, ethanol, isopropyl alcohol, and
n-butanol are particularly preferable, from the viewpoint that the
dispersibility of the perovskite type composite oxide is good.
[0046] Moreover, in step (A1), in order to disperse the perovskite
type composite oxide uniformly in the solvent, a dispersing device
such as a high-speed agitator, a colloid mill and a homogenizer may
be used as necessary, and in addition, a commonly used dispersant
may be added as necessary to the slurry.
[0047] In step (A2), the first component source, the second
component source, and a catalyst are added to the slurry prepared
in step (A1), followed by performing a hydrolysis reaction, so that
a hydrolyzed product is precipitated uniformly on the particle
surface of the perovskite type composite oxide.
[0048] Further, the second component source may be used singly or
in combination of two or more kinds thereof.
[0049] The total of the addition amounts of the first component
source and the second component source may be determined
appropriately, taking into consideration the solubility in a
solvent or a dilution medium, a reaction yield, or the like, such
that the above-described preferable coating ratio is given.
[0050] As the catalyst, inorganic alkali such as ammonia, sodium
hydroxide, and potassium hydroxide, inorganic alkaline salts such
as ammonium carbonate, ammonium bicarbonate, sodium carbonate, and
sodium hydrogen carbonate, organic alkalis such as monomethylamine,
dimethylamine, trimethylamine, monoethylamine, diethylamine,
triethylamine, ethylenediamine, pyridine, aniline, choline,
guanidine, tetramethylammonium hydroxide, and tetrapropylammonium
hydroxide, or organic alkaline salts such as ammonium formate,
ammonium acetate, monomethylamine formate, dimethylamine acetate,
pyridine lactate, guanidinoacetic acid, and aniline acetate may be
used. Among these, when a hydrophilic organic solvent is used as
the solvent, organic alkalis such as tetramethylammonium hydroxide,
and tetrapropylammonium hydroxide are preferable.
[0051] The addition amount of the catalyst is preferably 0.2 to 10,
and more preferably 0.5 to 5 as a molar ratio with respect to a
total of the first component source and the second component
source. Further, the catalyst is preferably added to the slurry in
the form of a solution obtained by dissolving it in water.
[0052] As conditions for the hydrolysis reaction, the reaction
temperature is preferably 40.degree. C. to 120.degree. C., and
preferably 50.degree. C. to 90.degree. C., and the reaction time is
preferably 1 hour or more, and more preferably 3 hours to 10 hours.
In addition, the hydrolysis reaction is preferably carried out
under stirring.
[0053] After completion of the hydrolysis reaction, solid-liquid
separation is carried out according to an ordinary method, and the
resultant is washed as necessary to recover a perovskite type
composite oxide coated with the hydrolyzed product, which is then
dried, and subjected to a slight cracking, as necessary. The
recovering method is not particularly limited, and means such as
spray drying may be applied.
[0054] Further, as for the conditions for the drying treatment, the
drying temperature is preferably 40.degree. C. or higher, more
preferably 60.degree. C. to 120.degree. C., and the drying time is
preferably 1 hour or more, and more preferably 3 hours to 10 hours.
In addition, a vacuum pump or the like may be used in combination
and drying can be performed even under reduced pressure.
[0055] Step (A3) is a step of calcining the dried product (the
perovskite type composite oxide coated with the hydrolyzed product)
obtained in step (A2), preferably at 400.degree. C. or higher, and
more preferably at 600.degree. C. to 1200.degree. C., so as to form
a coating.
[0056] In the method for preparing the modified perovskite type
composite oxide of the present invention, the perovskite type
composite oxide coated with the hydrolyzed product is calcined, so
that elution of A-site metal elements can be noticeably reduced
further. If the calcining temperature is too low, organic matter
remains in the coating components and densification of the coating
is insufficient. Thus, the effect of reduction in the elution of
the A-site metals is low, and sometimes, elution of a coating
component from the coating components modifying the perovskite type
composite oxide increases, the A-site metal-eluted amount becomes
larger than that prior to coating, or the relative dielectric
constant is reduced. On the other hand, if the calcining
temperature is too high, fusion between the particles or particle
growth becomes significant, and even though the cracking treatment
is carried out, the shape or the particle size distribution tends
to deviate considerably from that prior to modification, and
therefore, the calcining temperature is preferably 1200.degree. C.
or lower. Further, the calcining time is preferably 2 hours or
longer, and more preferably 3 hours to 10 hours.
[0057] After calcining, by performing cooling properly and carrying
out a cracking treatment, a modified perovskite type composite
oxide having a particle surface coated with a coating layer
including a first component of at least one selected from TiO.sub.2
and SiO.sub.2 and a second component of at least one selected from
a group consisting of Al, Zr, Nd, La, Ce, Pr, and Sm can be
obtained. The modified perovskite type composite oxide of the
present invention has good cracking traits, and thus any cracking
treatment is sufficient as long as it is usually carried out in an
ordinarily used mixer such as a food mixer and a coffee mill as a
small-scale device, and a Henschel mixer or the like as an
industrial device.
[0058] As for the modified perovskite type composite oxide of the
present invention thus obtained, the dielectric characteristics are
equal to or better than those prior to modification, there is no
substantial elution of coating components from the coating
components modifying the perovskite type composite oxide, the
change in the specific surface areas over time is suppressed, and
also, the elution of the A-site metals such as Ba, Ca, Sr, and Mg
that are eluted by the contact with a water content or the like is
noticeably reduced. In addition, it is possible to obtain a
particle size distribution that is close to the particle size
distribution prior to treatment only by performing a slight
cracking treatment, which corresponds to good cracking traits.
Further, when the particle surface of the modified perovskite type
composite oxide of the present invention is further
surface-modified with a silane coupling agent or the like, the
cracking traits are good, and accordingly, it becomes possible to
carry out the modification uniformly while keeping the particle
size distribution close to the particle size distribution of the
perovskite type composite oxide, and the affinity with the polymer
material as described later is improved.
[0059] For this reason, the modified perovskite type composite
oxide of the present invention can be particularly preferably used
as an inorganic filler which is used for a composite dielectric
material including a polymeric material such as a thermosetting
resin, a thermoplastic resin, and a photosensitive resin, and an
inorganic filler. Moreover, the modified perovskite type composite
oxide can also be applied to other applications such as an external
additive agent for a toner.
[0060] Next, the composite dielectric material of the present
invention will be described.
[0061] The composite dielectric material of the present invention
includes a polymeric material and the modified perovskite type
composite oxide as an inorganic filler.
[0062] The composite dielectric material of the present invention
is preferably a material having a relative dielectric constant of
15 or more, and more preferably 20 or more, which can be produced
by incorporating preferably 60% by mass or more, and more
preferably 70% by mass to 90% by mass of the modified perovskite
type composite oxide to the polymeric material as described
later.
[0063] Examples of the polymeric material that can be used in the
present invention include a thermosetting resin, a thermoplastic
resin, and a photosensitive resin.
[0064] Examples of the thermosetting resin include known
thermosetting resins such as an epoxy resin, a phenol resin, a
polyimide resin, a melamine resin, cyanate resins, bismaleimides,
addition polymers of bismaleimides and diamine, a multifunctional
cyanic ester resin, a double-bond-added polyphenylene oxide resin,
an unsaturated polyester resin, a polyvinyl benzyl ether resin, a
polybutadiene resin, and a fumarate resin. These thermosetting
resins may be used singly or in combination of two or more kinds
thereof. Among these thermosetting resins, an epoxy resin or a
polyvinyl benzyl ether resin is preferred, in terms of the balance
of heat resistance, workability, and price.
[0065] Examples of the epoxy resin used in the present invention
include monomers, oligomers, and polymers as a whole, which have at
least two epoxy groups in a single molecule. Examples of the epoxy
resin include: those obtained by epoxidation of novolac resins,
including, as typical examples, a phenol novolac epoxy resin and an
orthocresol novolac epoxy resin, which are obtained by condensing
or co-condensing, in the presence of an acidic catalyst, phenols
such as phenol, cresol, xylenol, resorcin, catechol, bisphenol A,
and bisphenol F and/or naphthols such as .alpha.-naphthol,
.beta.-naphthol, and dihydroxynaphthalene, and aldehydes such as
formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, and
salicylaldehyde, those obtained by epoxidation of additions or
polyadditions of diglycidyl ethers or phenols such as bisphenol A,
bisphenol B, bisphenol F, bisphenol S, and alkyl-substituted or
alkyl-unsubstituted bisphenol, and dicyclopentadienes or terpenes,
glycidyl ester epoxy resins obtained by the reaction of a polybasic
acid such as phthalic acid, and a dimer acid with epichlorohydrin,
glycidyl amine epoxy resins obtained by the reaction of polyamine
such as diaminodiphenylmethane, and isocyanuric acid with
epichlorohydrin, linear aliphatic epoxy resins obtained by
oxidizing an olefin bond with a peracid such as peracetic acid, and
alicyclic epoxy resins. These may be used singly or in combination
of two or more kinds thereof.
[0066] All epoxy resin curing agents that are known to persons
skilled in the art can be used herein, but particular examples
thereof include C.sub.2-C.sub.20 linear aliphatic diamines such as
ethylenediamine, trimethylenediamine, tetramethylenediamine, and
hexamethylenediamine, amines such as metaphenylenediamine,
paraphenylenediamine, paraxylenediamine,
4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylpropane,
4,4'-diaminodiphenylether, 4,4'-diaminodiphenylsulfone,
4,4'-diaminodicyclohexane, bis(4-aminophenyl)phenylmethane,
1,5-diaminonaphthalene, metaxylylenediamine, paraxylylenediamine,
1,1-bis(4-aminophenyl)cyclohexane, and dicyanodiamide, novolac-type
phenol resins such as a phenol novolac resin, a cresol novolac
resin, a tert-butylphenol novolac resin, and a nonylphenol novolac
resin, resol-type phenol resins, polyoxystyrenes such as
polyparaoxystyrene, phenol aralkyl resins, phenol resins obtained
by co-condensation of a phenol compound in which a hydrogen atom
binding to an aromatic ring other than a benzene ring or a
naphthalene ring is substituted with a hydroxyl group, with a
carbonyl compound, such as a naphthol aralkyl resin, and an acid
anhydride. These may be used singly or in combination of two or
more kinds thereof.
[0067] The blending amount of the epoxy resin curing agent is an
equivalent ratio in the range from preferably 0.1 to 10, and more
preferably 0.7 to 1.3, with respect the epoxy resin.
[0068] In addition, for the purpose of promoting the curing
reaction of the epoxy resin in the present invention, a known
curing promoter may be used. Examples of the curing promoter
include tertiary amine compounds such as
1,8-diaza-bicyclo(5,4,0)undecene-7, triethylenediamine, and
benzyldimethylamine, imidazole compounds such as 2-methylimidazole,
2-ethyl-4-methylimidazole, 2-phenylimidazole, and
2-phenyl-4-methylimidazole, organic phosphine compounds such as
triphenylphosphine and tributylphosphine, phosphonium salts, and
ammonium salts. These may be used singly or in combination of two
or more kinds thereof.
[0069] The polyvinyl benzyl ether resin used in the present
invention is obtained from a polyvinyl benzyl ether compound. The
polyvinyl benzyl ether compound is preferably a compound
represented by the following general formula (1):
##STR00001##
[0070] In the general formula (I), R.sub.1 represents a methyl
group or an ethyl group, and R.sub.2 represents a hydrogen atom or
a hydrocarbon group having 1 to 10 carbon atoms. The hydrocarbon
group represented by R.sub.2 is an alkyl group, an aralkyl group,
an aryl group, or the like, which may have a substituent. Examples
of the alkyl group include a methyl group, an ethyl group, a propyl
group, and a butyl group. Examples of the aralkyl group include a
benzyl group. Examples of the aryl group include a phenyl group.
R.sub.3 represents a hydrogen atom or a vinylbenzyl group. Further,
the hydrogen atom of R.sub.3 is derived from a starting compound
used in the synthesis of the compound represented by the general
formula (I). When the molar ratio of the hydrogen atom to the
vinylbenzyl group is 60:40 to 0:100, the curing reaction can be
promoted sufficiently, and further, in the composite dielectric
material of the present invention, sufficient dielectric
characteristics are obtained, which is thus preferable. n
represents an integer of 2 to 4.
[0071] The polyvinyl benzyl ether compound may be singly
polymerized as a resin material and then used, or it may be
copolymerized with other monomers and then used. Examples of the
copolymerizable monomers include styrene, vinyltoluene,
divinylbenzene, divinyl benzyl ether, allylphenol, allyloxybenzene,
diallyl phthalate, acrylic acid ester, methacrylic acid ester,
vinylpyrrolidone, and a denaturated product thereof. The blending
ratio of these monomers is 2% by mass to 50% by mass with respect
to the polyvinyl benzyl ether compound.
[0072] Polymerization and curing of the polyvinyl benzyl ether
compound can be carried out by known methods. The curing can be
carried out either in the presence or absence of a curing agent. As
the curing agent, known radical polymerization initiators such as
benzoyl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide,
and t-butyl perbenzoate can be used. The amount of curing agent to
be used is 0 part by mass to 10 parts by mass of the curing agent
with respect to 100 parts by mass of the polyvinyl benzyl ether
compound. ***The curing temperature varies depending on the
presence or absence of a curing agent and the type of curing agent,
but in order to sufficiently cure the polyvinyl benzyl ether
compound, the curing temperature is preferably 20.degree. C. to
250.degree. C., and more preferably at 50.degree. C. to 250.degree.
C.
[0073] In order to adjust the curing, hydroquinone, benzoquinone,
copper salts, or the like may be blended.
[0074] Examples of the thermoplastic resin include known
thermoplastic resins such as a (meth)acryl resin, a hydroxystyrene
resin, a novolac resin, a polyester resin, a polyimide resin, a
nylon resin, and a polyetherimide resin.
[0075] Examples of the photosensitive resin include known
photosensitive resins such as a photopolymerizable resin and a
photocrosslinking resin.
[0076] Examples of the photopolymerizable resin which is used in
the present invention include those containing an acrylic copolymer
having an ethylene unsaturated group (a photosensitive oligomer), a
photopolymerized compound (a photosensitive monomer), and a
photopolymerization initiator, and those containing an epoxy resin
and a photo-cation polymerization initiator. Examples of the
photosensitive oligomer include a product obtained by adding
acrylic acid to an epoxy resin, a product obtained by further
reacting the product with an acid anhydride, a product obtained by
reacting a copolymer containing a (meth)acryl monomer having a
glycidyl group with (meth)acrylic acid, a product obtained by
further reacting the product with an acid anhydride, a product
obtained by reacting a copolymer containing a (meth)acryl monomer
having a hydroxyl group with glycidyl (meth)acrylate, a product
obtained by further reacting the product with an acid anhydride,
and a product obtained by reacting a copolymer containing a maleic
anhydride with a (meth)acryl monomer having a hydroxyl group or a
(meth)acryl monomer having a glycidyl group. These may be used
singly or in combination of two or more kinds thereof.
[0077] Examples of the photopolymerizable compound (a
photosensitive monomer) include 2-hydroxyethyl (meth)acrylate,
2-hydroxypropyl (meth)acrylate, N-vinylpyrrolidone,
acryloylmorpholine, methoxy polyethylene glycol (meth)acrylate,
polyethylene glycol di(meth)acrylate, polypropylene glycol
di(meth)acrylate, N,N-dimethyl acrylamide, phenoxyethyl
(meth)acrylate, cyclohexyl (meth)acrylate, trimethylolpropane
(meth)acrylate, pentaerythritol tri(meth)acrylate,
dipentaerythritol hexa(meth)acrylate,
tris(hydroxyethyl)isocyanurate di(meth)acrylate, and
tris(hydroxyethyl)isocyanurate tri(meth)acrylate. These may be used
singly or in combination of two or more kinds thereof.
[0078] Examples of the photopolymerization initiator include
benzoin and alkyl ethers thereof, benzophenones, acetophenones,
anthraquinones, xanthones, and thioxanthones. These may be used
singly or in combination of two or more kinds thereof. In addition,
commonly used known photopolymerization promoters such as benzoic
acid-type promoters, and tertiary amine-type promoters may be used
in combination with such photopolymerization initiators. Examples
of a photo-cationic polymerization initiator include
triphenylsulfonium hexafluoroantimonate, diphenylsulfonium
hexafluoroantimonate, triphenylsulfonium hexafluorophosphate,
benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, and
ferrous aromatic compound salts of Bronsted acid (Nihon Ciba-Geigy
K. K., CG24-061). These may be used singly or in combination of two
or more kinds thereof.
[0079] With the use of a photo-cationic polymerization initiator,
an epoxy resin is subjected to ring-opening polymerization. The
reaction rate of photo polymerization is higher when using an
alicyclic epoxy resin than when using a common glycidyl ester epoxy
resin. Thus, the use of such an alicyclic epoxy resin is
preferable. It may also be possible to use an alicyclic epoxy resin
in combination with a glycidyl ester epoxy resin. Examples of the
alicyclic epoxy resin include vinylcyclohexene diepoxide, alicyclic
diepoxyacetal, alicyclic diepoxyadipate, alicyclic
diepoxycarboxylate, and EHPE-3150 manufactured by Daicel Chemical
Industries, Ltd. These may be used singly or in combination of two
or more kinds thereof.
[0080] Examples of the photocrosslinking resin include a
water-soluble polymer dichromate, a vinyl polycinnamate (Kodak
KPR), and a cyclized rubber azide (Kodak KTFR). These may be used
singly or in combination of two or more kinds thereof.
[0081] The dielectric constant of the photosensitive resin is
generally as low as 2.5 to 4.0. Accordingly, in order to increase
the dielectric constant of a binder, a higher-dielectric polymer
(for example, SDP-E of Sumitomo Chemical Co., Ltd. (.di-elect
cons.: 15<), a cyano resin of Shin-Etsu Chemical Co., Ltd.
(.di-elect cons.: 18<)), and a higher-dielectric liquid (for
example, SDP-S of Sumitomo Chemical Co., Ltd. (.di-elect cons.:
40<)) may be added within a range which does not impair the
photosensitive characteristics of the photosensitive resin.
[0082] In the present invention, the polymeric materials may be
used singly or in combination of two or more kinds thereof.
[0083] In the composite dielectric material of the present
invention, the blending amount of the modified perovskite type
composite oxide is preferably 60% by mass or more, and more
preferably 70% by mass to 90% by mass as a blending ratio during
composition with the resin. This is because, if the blending amount
of the modified perovskite type composite oxide is less than 60% by
mass, there is a tendency that a sufficient relative dielectric
constant may not be obtained, whereas if it is more than 90% by
mass, there is a tendency that the viscosity increases and the
dispersibility deteriorates, and also there is concern, for
example, that sufficient strength cannot be obtained or the like
during consolidation of a composite. The composite dielectric
material is preferably a material having a relative dielectric
constant of preferably 15 or more, and more preferably 20 or more
through blending.
[0084] In addition, the composite dielectric material of the
present invention may include other fillers in an addition amount
within the range that does not impair the effect of the present
invention. Examples of other filler include fine carbon powders
such as acetylene black and ketchen black, fine graphite powders,
and silicon carbide.
[0085] Moreover, to the composite dielectric material of the
present invention may be added a curing agent, glass powders, a
coupling agent, a polymer additive, a reaction diluent, a
polymerization inhibitor, a leveling agent, a wetting improver, a
surfactant, a plasticizer, an ultraviolet absorber, an antioxidant,
an antistatic agent, an inorganic filler, a fungicide, a humidity
controller, a dye-dissolving agent, a buffer, a chelating agent, a
fire retardant, and a silane coupling agent (an integral blending
method) within the range that does not impair the effect of the
present invention. These additives may be used singly or in
combination of two or more kinds thereof.
[0086] The composite dielectric material of the present invention
can be prepared by preparing a composite dielectric paste, and then
eliminating an organic solvent or performing a curing reaction or a
polymerization reaction.
[0087] The composite dielectric paste contains resin components,
the modified perovskite type composite oxide, and an additive and
an organic solvent, which may be added as necessary.
[0088] The resin components contained in the composite dielectric
paste are a polymerizable compound of a thermosetting resin, a
polymer of a thermoplastic resin, or a polymerizable compound of a
photosensitive resin. These resin components may be used singly or
in combination of two or more kinds thereof.
[0089] The polymerizable compound as used herein means a compound
having a polymerizable group, and examples thereof include a
precursor polymer prior to complete curing, a polymerizable
oligomer, and a monomer. In addition, the polymer as used herein
means a compound obtained after a polymerization reaction has been
substantially completed.
[0090] The organic solvent added as necessary varies depending on
the resin components used. The organic solvent is not particularly
limited as long as it is able to dissolve the resin components, but
examples thereof include N-methylpyrrolidone, dimethylformamide,
ether, diethyl ether, tetrahydrofuran, dioxane, ethyl glycol ether
of monoalcohol containing 1 to 6 carbon atoms having a linear or
branched alkyl group, propylene glycol ether, butyl glycol ether,
ketone, acetone, methyl ethyl ketone, methyl isopropyl ketone,
methyl isobutyl ketone, cyclohexanone, ester, ethyl acetate, butyl
acetate, ethylene glycol acetate, methoxy propyl acetate, methoxy
propanol, other halogen hydrocarbons, alicyclic hydrocarbons, and
aromatic hydrocarbons. These organic solvent may be used singly or
in combination of two or more kinds thereof. Among these, hexane,
heptane, cyclohexane, toluene, and dixylene are preferred.
[0091] In the present invention, the composite dielectric paste is
prepared to have a desired viscosity, and then used. The viscosity
of the composite dielectric paste is usually 1,000 mPas to
1,000,000 mPas (25.degree. C.), and in consideration of the coating
property of the composite dielectric paste, it is preferably 10,000
mPas to 600,000 mPas (25.degree. C.).
[0092] The composite dielectric material of the present invention
can be processed into a molded body having a film shape, a bulk
shape, or a predetermined shape, and then used. It can be
particularly used as a high-dielectric film having a thin film
shape.
[0093] In order to prepare a composite dielectric film using the
composite dielectric material of the present invention, it may be
prepared according to a conventional known method of using a
composite dielectric paste. An example will be given below.
[0094] The composite dielectric paste can be applied to a
substrate, and then dried to mold it into one having a film shape.
As such a substrate, a plastic film on the surface of which a
delamination treatment has been performed can be used, for example.
When the composite dielectric paste is applied onto the plastic
film on the surface of which a delamination treatment has been
performed when molding into a film form, it is preferable that it
be generally molded into a film state and then the substrate be
peeled from the film before use. Examples of the plastic film used
as a substrate include films such as a polyethylene terephthalate
(PET) film, a polyethylene film, a polypropylene film, a polyester
film, a polyimide film, and films made of aramid, kapton, and
polymethylpentene. Further, the plastic film used as a substrate
has a thickness of preferably 1 .mu.m to 100 .mu.m, and more
preferably 1 .mu.m to 40 .mu.m. In addition, as a mold-releasing
treatment performed on the surface of the substrate, a
mold-releasing treatment in which silicon, wax, a fluorine resin,
or the like is applied onto the surface is preferably used.
[0095] Moreover, a metallic foil may be used as a substrate, and a
dielectric film may be formed on the metallic foil. In such a case,
the metallic foil used as a substrate can be used as an electrode
of a condenser.
[0096] The method of applying the composite dielectric paste onto
the substrate is not particularly limited, and a common application
method can be used. For example, the application can be carried out
using a roller method, a spray method, a silk-screen method, or the
like.
[0097] After the dielectric film has been incorporated into a board
such as a printed board, it can be thermally cured by heating.
Further, when a photosensitive resin is used, it can be subjected
to patterning by selective exposure.
[0098] Moreover, the composite dielectric material of the present
invention may be subjected to extrusion molding according to a
calendar method or the like, so that it may be molded into one
having a film shape.
[0099] The extrusion-molded dielectric film may be molded such that
it may be extruded onto the substrate. Further, when a metallic
foil is used as a substrate, as the metallic foil, a foil made from
copper, aluminum, brass, nickel, iron, or the like as the material,
a foil including the alloy thereof, a composite foil, or the like
can be used. Treatments such as a surface roughening treatment and
application of an adhesive may be carried out on the metallic foil,
as necessary.
[0100] In addition, a dielectric film may be formed between the
metallic foils. In this case, the composite dielectric paste may be
applied to a metallic foil, and another metallic foil may be placed
thereon. Thereafter, the composite dielectric paste may be dried in
a state in which it is sandwiched between the metallic foils, so as
to form a dielectric film that is in a state in which it is
sandwiched between the metallic foils. Moreover, the dielectric
film may also be formed between such metallic foils by subjecting
the film to extrusion molding so that the dielectric film may be
sandwiched between the metallic foils.
[0101] In addition, the composite dielectric material of the
present invention may be processed into a varnish using the organic
solvent as described above, and a cloth or non-woven fabric may be
impregnated with this varnish. It may be then dried to prepare a
prepreg. The type of the cloth or non-woven fabric that can be used
herein is not particularly limited, and known ones may be used.
Examples of the cloth include a glass cloth, an aramid cloth, a
carbon cloth, and stretched porous polytetrafluoroethylene.
Examples of the non-woven fabric include an aramid non-woven fabric
and a glass paper. The prepreg is laminated on an electronic part
such as a circuit board, followed by curing, so that an insulation
layer can be introduced into the electronic parts.
[0102] The composite dielectric material of the present invention
has a high relative dielectric constant. Thus, it can be preferably
used as a dielectric layer for electronic parts, particularly
electronic parts such as a print circuit board, a semiconductor
package, a condenser, a high-frequency antenna, and an inorganic
EL.
[0103] In order to prepare a multilayer print wiring board using
the composite dielectric material of the present invention, it can
be prepared by a method known in the present technical field (see,
for example, Japanese Patent Laid-Open Nos. 2003-192768,
2005-29700, 2002-226816, 2003-327827, and the like). Further, the
following example shows a case in which a thermosetting resin is
used as a polymeric material of the composite dielectric
material.
[0104] The composite dielectric material of the present invention
is processed into the dielectric film. The resin surface of the
dielectric film is laminated on a circuit board by pressurization,
heating, or using a vacuum laminator. After lamination, the
substrate is peeled from the film, a metallic foil is further
laminated on the exposed resin layer, and the resin is then cured
by heating.
[0105] Further, the composite dielectric material of the present
invention is processed into a prepreg, but the lamination onto a
circuit board can be carried out by vacuum pressing. Specifically,
it is preferable that one surface of the prepreg be allowed to come
into contact with a circuit board, and that a metallic foil be
placed on the other surface, followed by pressing.
[0106] In addition, the composite dielectric material of the
present invention can be used as varnish, and the varnish can be
applied onto a circuit board by screen printing, curtain coating,
roll coating, spray coating, or the like, and then dried to form an
intermediate insulation layer of a multilayer printed wiring
board.
[0107] In the present invention, when a printed wiring board
including an insulation layer at the outermost layer is prepared, a
through hole part or a via hole part is made using a drill or a
laser, and the surface of an insulation layer is treated with a
roughening agent to form fine bumps and dips. As a method of
roughening an insulation layer, a method of immersing a board, on
which an insulation resin layer has been formed, in a solution of
an oxidizer and the like, a method of spraying a solution of an
oxidizer and the like, etc. can be applied depending on the
technical specification. Specific examples of the roughening agent
include oxidizers such as dichromate, permanganate, ozone, hydrogen
peroxide/sulfuric acid, and nitric acid, organic solvents such as
N-methyl-2-pyrrolidone, N,N-dimethylformamide, and methoxypropanol,
alkaline aqueous solutions such as caustic soda and caustic potash,
acidic aqueous solutions such as sulfuric acid and hydrochloric
acid, and various types of plasma treatments. These treatments may
be used in combination. As described above, a printed wiring board,
on which an insulation layer has been roughened, is then subjected
to dry plating such as evaporation, sputtering, and ion plating,
and wet plating such as non-electrolytic and electrolytic plating,
so as to form a conductor layer thereon. At this time, it may also
be possible to form a plating resist in a pattern opposite to the
conductor layer, and to form a conductor layer only by
non-electrolytic plating. After a conductor layer has been formed
as described above, it may be subjected to an annealing treatment
to promote the curing of a thermosetting resin, to further improve
the peeling strength of the conductor layer. Thus, a conductor
layer can be formed as an outermost layer.
[0108] Moreover, a metallic foil that forms the intermediate
insulation layer may be multilayered by laminating it by a vacuum
press. Such metallic foil that forms an intermediate insulation
layer is laminated on a printed wiring board, in which an inner
layer circuit has been formed, by a vacuum press, to produce a
printed wiring board including a conductor layer as an outermost
layer thereof. Furthermore, a prepreg using the composite
dielectric material of the present invention, together with a
metallic foil, is laminated on the printed wiring board, in which
an inner layer circuit has been formed, by a vacuum press, to
produce a printed wiring board including a conductor layer as an
outermost layer thereof. A certain through hole or a via hole is
made by a conformal method using a drill or a laser, and desmearing
is then performed on the insides of such through hole and via hole,
to form fine bumps and dips. Thereafter, wetting plating such as
non-electrolytic and electrolytic plating is performed to enable
conduction between layers.
[0109] Further, these steps are repeated several times, as
necessary, and after completion of the circuit formation of the
outermost layer, a solder resist is subjected to pattern printing
and thermosetting according to a screen printing method, or to
whole surface printing/thermosetting according to curtain coating,
roll coating, or spray coating. Thereafter, a pattern is formed
with a laser to obtain a desired multilayer printed wiring
board.
EXAMPLES
[0110] Hereinbelow, the present invention will be described with
reference to Examples. However, the present invention is not
intended to be limited thereto.
<Perovskite Type Composite Oxide Sample>
[0111] As a perovskite type composite oxide sample to be modified,
commercially available one
(Ba.sub.0.92Ca.sub.0.08)(Ti.sub.0.71Zr.sub.0.29)O.sub.3 (average
particle diameter 0.76 .mu.m, and BET specific surface area 2.17
m.sup.2/g) which had been obtained by a solid-phase method was
used. Further, the average particle diameter was determined by a
laser light scattering method. In addition, 4 g of the perovskite
type composite oxide was dispersed in 100 ml of pure water to
prepare a 4%-by-mass slurry. The slurry was stirred at 25.degree.
C. at 100 rpm for 1 hour, and the pH of the supernatant was then
measured with a pH meter. As a result, the pH was 9.22.
Example 1
Perovskite Type Composite Oxide Coated with TiO.sub.2/Nd
(Step A1)
[0112] 100 parts by mass of a perovskite type composite oxide
sample was added to 150 parts by mass of n-butanol, and the mixture
was sufficiently dispersed to prepare a slurry.
(Step A2)
[0113] 1.7 parts by mass of tetra-n-butoxytitanium (hydrolyzable
TiO.sub.2 precursor) and 0.9 parts by mass of neodymium acetate
monohydrate (salt of Nd) were added to the slurry obtained in step
A1 under stirring, and subsequently, 3 parts by mass of a
20%-by-mass aqueous tetramethylammonium hydroxide solution was
added thereto. Then, a hydrolysis reaction was carried out at
90.degree. C. for 3 hours. After completion of the hydrolysis
reaction, solid-liquid separation was carried out according to an
ordinary method, and the separated cake thus obtained was dispersed
in 300 parts by mass of ethanol, and the dispersion was then
stirred for 1 hour. Thereafter, solid-liquid separation was carried
out again, and the resultant was dried at 80.degree. C. for 20
hours, followed by cracking, to obtain a perovskite type composite
oxide having a hydrolyzed product precipitated on the particle
surface.
(Step A3)
[0114] The perovskite type composite oxide obtained in step A2 was
calcined at 1000.degree. C. for 4 hours in air to obtain a modified
perovskite type composite oxide, in which the particle surface was
coated with a coating layer including TiO.sub.2 and Nd. Various
physical properties of the modified perovskite type composite oxide
sample thus obtained are shown in Table 1. Further, 4 g of the
modified perovskite type composite oxide sample was dispersed in
100 ml of pure water to prepare a 4%-by-mass slurry. The slurry was
stirred at 25.degree. C. at 100 rpm for 1 hour, and the pH of the
supernatant was then measured with a pH meter. As a result, the pH
was 7.40.
Example 2
Perovskite Type Composite Oxide Coated with TiO.sub.2/La
[0115] In the same manner as in Example 1 except that lanthanum
acetate 1.5-hydrate (salt of La) was used instead of neodymium
acetate monohydrate (salt of Nd), a modified perovskite type
composite oxide sample coated with a coating layer including
TiO.sub.2 and La was obtained. Various physical properties of the
modified perovskite type composite oxide sample thus obtained are
shown in Table 1. Further, the pH of the modified perovskite type
composite oxide sample was measured in the same manner as in
Example 1, and as a result, the pH was 7.46.
Example 3
Perovskite Type Composite Oxide Coated with TiO.sub.2/Ce
[0116] In the same manner as in Example 1 except that cerium
acetate monohydrate (salt of Ce) was used instead of neodymium
acetate monohydrate (salt of Nd), a modified perovskite type
composite oxide sample coated with a coating layer including
TiO.sub.2 and Ce was obtained. Various physical properties of the
modified perovskite type composite oxide sample thus obtained are
shown in Table 1. Further, the pH of the modified perovskite type
composite oxide sample was measured in the same manner as in
Example 1, and as a result, the pH was 7.23.
Example 4
Perovskite Type Composite Oxide Coated with TiO.sub.2/Pr
[0117] In the same manner as in Example 1 except that praseodymium
acetate dihydrate (salt of Pr) was used instead of neodymium
acetate monohydrate (salt of Nd), a modified perovskite type
composite oxide sample coated with a coating layer including
TiO.sub.2 and Pr was obtained. Various physical properties of the
modified perovskite type composite oxide sample thus obtained are
shown in Table 1. Further, the pH of the modified perovskite type
composite oxide sample was measured in the same manner as in
Example 1, and as a result, the pH was 7.51.
Example 5
Perovskite Type Composite Oxide Coated with TiO.sub.2/Sm
[0118] In the same manner as in Example 1 except that samarium
acetate tetrahydrate (salt of Sm) was used instead of neodymium
acetate monohydrate (salt of Nd), a modified perovskite type
composite oxide sample coated with a coating layer including
TiO.sub.2 and Sm was obtained. Various physical properties of the
modified perovskite type composite oxide sample thus obtained are
shown in Table 1. Further, the pH of the modified perovskite type
composite oxide sample was measured in the same manner as in
Example 1, and as a result, the pH was 7.34.
Example 6
Perovskite Type Composite Oxide Coated with TiO.sub.2/Nd
[0119] In the same manner as in Example 1 except that the calcining
temperature was changed to 650.degree. C., a modified perovskite
type composite oxide sample coated with a coating layer including
TiO.sub.2 and Nd was obtained. Various physical properties of the
modified perovskite type composite oxide sample thus obtained are
shown in Table 1. Further, the pH of the modified perovskite type
composite oxide sample was measured in the same manner as in
Example 1, and as a result, the pH was 7.43.
Example 7
Perovskite Type Composite Oxide Coated with SiO.sub.2/Al
(Step A1)
[0120] 100 parts by mass of a perovskite type composite oxide
sample was added to 150 parts by mass of ethanol, followed by
sufficiently carrying out dispersion, to prepare a slurry.
(Step A2)
[0121] 1 part by mass of tetraethoxysilane (hydrolyzable SiO.sub.2
precursor) and 2 parts by mass (diluted 3-fold with water) of
aluminum acetate (salt of Al) were added to the slurry obtained in
step A1 under stirring, and subsequently, 2 parts by mass of a
20%-by-mass aqueous tetramethylammonium hydroxide solution was
added thereto. Then, a hydrolysis reaction was carried out at
60.degree. C. for 3 hours. After completion of the hydrolysis
reaction, solid-liquid separation was carried out according to an
ordinary method, and the separated cake thus obtained was dispersed
in 300 parts by mass of ethanol, and the dispersion was then
stirred for 1 hour. Thereafter, solid-liquid separation was carried
out again, and the resultant was dried at 80.degree. C. for 20
hours, followed by cracking, to obtain a perovskite type composite
oxide having a hydrolyzed product precipitated on the particle
surface.
(Step A3)
[0122] The perovskite type composite oxide obtained in step A2 was
calcined at 1050.degree. C. for 4 hours in air to obtain a modified
perovskite type composite oxide, in which the particle surface was
coated with a material including SiO.sub.2 and Nd. Various physical
properties of the modified perovskite type composite oxide sample
thus obtained are shown in Table 1. Further, 4 g of the modified
perovskite type composite oxide sample was dispersed in 100 ml of
pure water to prepare a 4%-by-mass slurry. The slurry was stirred
at 25.degree. C. at 100 rpm for 1 hour, and the pH of the
supernatant was then measured with a pH meter. As a result, the pH
was 8.18. The coating amounts of SiO.sub.2 and Al.sub.2O.sub.3 were
0.09% by mass and 0.15% by mass, respectively.
Example 8
Perovskite Type Composite Oxide Coated with SiO.sub.2/Nd
(Step A1)
[0123] 100 parts by mass of a perovskite type composite oxide
sample was added to 150 parts by mass of n-butanol, and the mixture
was sufficiently dispersed to prepare a slurry.
(Step A2)
[0124] 1.46 parts by mass of tetraethoxysilane (hydrolyzable
SiO.sub.2 precursor) and 2.38 parts by mass (diluted 6-fold with
water) of neodymium acetate monohydrate (salt of Nd) were added to
the slurry obtained in step A1 under stirring, and subsequently, 10
parts by mass of a 20%-by-mass aqueous tetramethylammonium
hydroxide solution was added thereto. Then, a hydrolysis reaction
was carried out at 90.degree. C. for 3 hours. After completion of
the hydrolysis reaction, solid-liquid separation was carried out
according to an ordinary method, and the separated cake thus
obtained was dispersed in 300 parts by mass of ethanol, and the
dispersion was then stirred for 1 hour. Thereafter, solid-liquid
separation was carried out again, and the resultant was dried at
80.degree. C. for 20 hours, followed by cracking, to obtain a
perovskite type composite oxide having a hydrolyzed product
precipitated on the particle surface.
(Step A3)
[0125] The perovskite type composite oxide obtained in step A2 was
calcined at 900.degree. C. for 4 hours in air to obtain a modified
perovskite type composite oxide, in which the particle surface was
coated with a material including SiO.sub.2 and Nd. Various physical
properties of the modified perovskite type composite oxide sample
thus obtained are shown in Table 1. Further, 4 g of the modified
perovskite type composite oxide sample was dispersed in 100 ml of
pure water to prepare a 4%-by-mass slurry. The slurry was stirred
at 25.degree. C. at 100 rpm for 1 hour, and the pH of the
supernatant was then measured with a pH meter. As a result, the pH
was 7.73. The coating amounts of SiO.sub.2 and Nd.sub.2O.sub.3 were
0.31% by mass and 1.09% by mass, respectively.
Comparative Example 1
Perovskite Type Composite Oxide Treated with Silane Coupling
Agent
[0126] 100 parts by mass of the perovskite type composite oxide
sample was put into a coffee mill. Under stirring, 1.2 parts by
mass of a silane coupling agent (manufactured by Shin-Etsu Chemical
Co., Ltd.; product name KBM-403) was added thereto over 1 minute,
followed by further stirring for 2 minutes. Thereafter, the treated
powders were taken out and then put into the coffee mill again,
followed by stirring for 2 minutes. Thereafter, the treated powders
were taken out. As a result of such operations, the concentration
of the silane coupling agent immobilized after a drying step was
calculated to be 0.73% by mass. The treated powders were left to
stand still and dried at 80.degree. C. for 20 hours. During the
drying, the silane coupling agent was subjected to a hydrolysis
step and a dehydration condensation process, to obtain a perovskite
type composite oxide sample treated with the silane coupling agent.
Various physical properties of the perovskite type composite oxide
sample treated with the silane coupling agent thus obtained are
shown in Table 1. Further, the pH of the perovskite type composite
oxide sample treated with the silane coupling agent was measured in
the same manner as in Example 1, and as a result, the pH of the
supernatant was 5.73.
Comparative Example 2
Perovskite Type Composite Oxide Coated with Al.sub.2O.sub.3
[0127] In the same manner as in Example 7 except that in step A2,
tetraethoxysilane was not used, 150 parts by mass of ethanol, 4.00
parts by mass (diluted 4-fold with water) of aluminum acetate (salt
of Al), and 4.00 parts by mass of a 20%-by-mass aqueous
tetramethylammonium solution were used, the condition for a
hydrolysis reaction was set at 60.degree. C. for 3 hours, and the
condition for calcining was set at 65.degree. C., a perovskite type
composite oxide sample coated with Al.sub.2O.sub.3 was obtained.
Various physical properties of the perovskite type composite oxide
sample coated with Al.sub.2O.sub.3 thus obtained are shown in Table
1. Further, the pH of the perovskite type composite oxide sample
coated with Al.sub.2O.sub.3 was measured in the same manner as in
Example 1, and as a result, the pH was 10.40.
TABLE-US-00001 TABLE 1 Calcining Total coating temperature Type of
Coating amount of amount (.degree. C.) coating each component (% by
mass) pH Example 1 1000 TiO.sub.2.cndot.Nd.sub.2O.sub.3 TiO.sub.2;
0.43% by mass 0.88 7.40 Nd.sub.2O.sub.3; 0.45% by mass Example 2
1000 TiO.sub.2.cndot.La.sub.2O.sub.3 TiO.sub.2; 0.42% by mass 0.84
7.46 La.sub.2O.sub.3; 0.42% by mass Example 3 1000
TiO.sub.2.cndot.Ce.sub.2O.sub.3 TiO.sub.2; 0.43% by mass 0.87 7.23
Ce.sub.2O.sub.3; 0.44% by mass Example 4 1000
TiO.sub.2.cndot.Pr.sub.2O.sub.3 TiO.sub.2; 0.40% by mass 0.82 7.51
Pr.sub.2O.sub.3; 0.42% by mass Example 5 1000 .sup.
TiO.sub.2.cndot.Sm.sub.2O.sub.3 TiO.sub.2; 0.36% by mass 0.75 7.34
Sm.sub.2O.sub.3; 0.39% by mass Example 6 650
TiO.sub.2.cndot.Nd.sub.2O.sub.3 TiO.sub.2; 0.43% by mass 0.88 7.43
Nd.sub.2O.sub.3; 0.45% by mass Example 7 1050
SiO.sub.2.cndot.Al.sub.2O.sub.3 SiO.sub.2; 0.09% by mass 0.24 8.18
Al.sub.2O.sub.3; 0.15% by mass Example 8 900
SiO.sub.2.cndot.Nd.sub.2O.sub.3 SiO.sub.2; 0.31% by mass 1.40 7.73
Nd.sub.2O.sub.3; 1.09% by mass Comparative -- Silane cou-
SiO.sub.2; 0.73% by mass 0.73 5.73 Example 1 pling agent
Comparative 650 Al.sub.2O.sub.3 Al.sub.2O.sub.3; 0.28% by mass 0.28
10.4 Example 2
[0128] Further, for various lanthanide components, Al, and Si in
Examples 1 to 8 and Comparative Example 2, the "total coating
amounts" in Table 1 were determined by dissolving the powders that
have been subjected to a coating treatment in an aqueous
hydrochloric acid solution, then directly performing a measurement
by means of ICP-AES, and converting the resultants in terms of to
oxides. Further, for TiO.sub.2, the total coating amounts were
determined by measuring Ti that had not been precipitated from the
solvent after the hydrolysis reaction by means of ICP-AES,
subtracting them from the addition amount to be charged, and then
converting the resultants in terms of oxides. These determined
values were added up for calculation. In Comparative Example 1, the
total coating amount was determined by measuring the carbon amount
in the sample thermally decomposed from the total solid carbon
analysis measurement.
<Dielectric Characteristics>
[0129] 9 g each of the modified perovskite type composite oxide
samples of Examples 1 to 8, and untreated perovskite type composite
oxide samples, 3 g of a thermosetting epoxy resin (manufactured by
Japan Epoxy Resins Co., Ltd., product name: EPICOAT 815, molecular
weight of about 330, specific gravity of 1.1, and nominal viscosity
at 25.degree. C. of 9 to 12 P), and 0.24 g of a curing promoter
(1-isobutyl-2-methylimidazole, nominal viscosity at 25.degree. C.
being 4 to 12 P) were kneaded using an agitator with a defoaming
function (manufactured by THINKY, product name: AWATORI RENTARO)
was used to prepare an epoxy resin composition. Further, the
kneading condition was as follows: the stirring operation was
carried out for 5 minutes and the defoaming operation was carried
out for 5 minutes.
[0130] Each of the obtained epoxy resin compositions was cured at
120.degree. C. for 30 minutes to prepare a composite dielectric
sample, and the dielectric characteristics were evaluated by an
ordinary method.
[0131] The dielectric characteristics of the composite dielectric
samples using the modified perovskite type composite oxide samples
of Examples 1 to 8 were compared with those obtained when using the
untreated perovskite type composite oxide samples, and thus, it was
found that they were equal to or better than those obtained when
using the untreated perovskite type composite oxide samples.
<Elution Test>
[0132] 4 g each of the modified perovskite type composite oxide
samples of Examples 1 to 8 and Comparative Examples 1 and 2 was
dispersed in 100 ml of pure water to prepare a 4%-by-mass slurry.
The slurry was stirred at 25.degree. C. at 100 rpm for 1 hour, and
was then separated by filtration. The concentrations of Ba and Ca
in the filtrate and the concentrations of Ti, Al, Nd, La, Ce, Pr,
Sm, and Si derived from the coating components were measured by
means of ICP-AES, and quantified as an eluted portion from the
samples. The results are shown in Table 2. Moreover, the untreated
perovskite type composite oxide samples were also presented as
Comparative Example 3 in Table 2.
<Evaluation of Cracking Traits>
[0133] 250 g each of the modified perovskite type composite oxide
samples of Examples 1 to 8 and Comparative Example's 1 and 2 was
put into a food mixer and subjected to a cracking treatment for 10
minutes. The average particle diameter of the sample after the
cracking treatment was determined by a laser light scattering
method. Taking the average particle diameter of the untreated
perovskite type composite oxide sample as a standard, an increase
rate in the average particle diameter of 50% or less was evaluated
as Cracking Traits .circleincircle., an increase rate of more than
50% and 100% or less was evaluated as Cracking Traits
.largecircle., an increase rate of more than 100% and 200% or less
was evaluated as Cracking Traits .DELTA., and an increase rate of
more than 200% was evaluated as Cracking Traits X. The results are
shown in Table 2.
<Change in Specific Surface Area Over Time>
[0134] Each of the modified perovskite type composite oxide samples
of Examples 1 to 6 and Comparative Examples 1 to 3, and the
untreated perovskite type composite oxide samples was exposed for
24 hours under an environment of a temperature 40.degree. C. and a
humidity of 90%, and the BET specific surface areas of the samples
were then measured. Further, the untreated perovskite type
composite oxide samples were taken as Comparative Example 3. The
BET specific surface area before exposure was taken as S1 and the
BET specific surface area after exposure was taken as S2, in which
the change rate [%] in the specific surface areas was determined by
the formula: (S2-S1)/S1.times.100. A change rate in the specific
surface area of 2% or less was evaluated as .circleincircle., a
change rate of more than 2% and 5% or less was evaluated as
.largecircle., a change rate of more than 5% and 10% or less was
evaluated as .DELTA., and a change rate of more than 10% was
evaluated as X. The results are shown in Table 2. Further, the BET
specific surface area was obtained by measuring the entire surface
areas of the measurement samples using MACSORB HM-1201 manufactured
by Mountech Co., Ltd., and normalized as measured values of the
samples.
TABLE-US-00002 TABLE 2 Coating component Ba-eluted Ca-eluted
Ti-eluted Si-eluted Other element Change in specif- amount amount
amount amount added-eluted Cracking ic surface areas (ppm) (ppm)
(ppm) (ppm) amount (ppm) traits over time Example 1 396 9 0 -- 0
.circleincircle. .circleincircle. Example 2 418 10 0 -- 0
.circleincircle. .circleincircle. Example 3 330 8 0 -- 0
.circleincircle. .circleincircle. Example 4 440 10 0 -- 0
.circleincircle. .circleincircle. Example 5 374 9 0 -- 0
.circleincircle. .circleincircle. Example 6 420 5 0 -- 3
.circleincircle. .circleincircle. Example 7 5 0 -- 10 21
.largecircle. .largecircle. Example 8 528 12 -- 5 0
.circleincircle. .circleincircle. Comparative 714 35 -- 321 -- X
.DELTA. Example 1 Comparative 1 0 -- -- 342 .circleincircle. X
Example 2 Comparative 788 52 -- -- -- -- X Example 3
[0135] The "other element added-eluted amount" in Table 2 is a
value obtained by measurement of each of Nd (Example 1, Example 6,
and Example 8), La (Example 2), Ce (Example 3), Pr (Example 4), Sm
(Example 5), and Al (Example 7 and Comparative Example 2) in the
filtrate.
[0136] As seen from the above-described results, in the modified
perovskite type composite oxides of Examples 1 to 8, the dielectric
characteristics were equal to or better than those prior to
modification, but elution of Ba and Ca was suppressed effectively
and elution of a coating component from the coating components was
also suppressed. Moreover, change in the specific surface areas
over time was small and the cracking traits were good.
INDUSTRIAL APPLICABILITY
[0137] The present invention can have the objectives to provide a
modified perovskite type composite oxide in which the dielectric
characteristics are equal to or better than those prior to
modification, there is no substantial elution of coating components
from the coating components modifying the perovskite type composite
oxide, change in the specific surface areas over time and elution
of the A-site metals of the perovskite type composite oxide are
suppressed effectively, while the cracking traits are good, a
method for preparing the same, and a composite dielectric material
using the modified perovskite type composite oxide.
* * * * *